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Harding Flying Bison
Harding University- Edmond Wilson, Ethan Lilly,
Eric, Locke, and David Stair
The goal of this mission is to measure
the absorption spectrum of Earth's atmosphere as
a function of altitude using a mini-spectrometer
as a science payload onboard a NASA
Terrier-Orion rocket that will reach an altitude
of 72 miles, the edge of the atmosphere.
Recent technology has produced
mini-spectrometers that operate in the
UV-VIS-NIR regions of the spectrum that
are compact, robust, lightweight, have no moving
parts, and have low power requirements.
Here we propose to study the earths atmosphere
in order to investigate if these
mini-spectrometers would be useful for solar
system exploration missions to learn about
atmospheric compositions of other worlds.
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The spectrometer measures atmospheric spectra
through an optical port in the rocket airframe
using Sunlight as the source. Science questions
to be answered are (1) what is the variation of
water vapor in Earth's atmosphere as a function
of altitude? (2) What is the concentration of
ozone as a function of altitude? (3) Can the
presence of NO2, N2), CO, I2, OH in the Earth's
atmosphere be detected with this instrument?
Spectrum obtained from our spectrometer
at 297 feet elevation. "Solar" refers to
pointing the spectrometer at the Sun while the
"N.E. Blue Sky has the instrument pointing away
from the Sun. Water and oxygen spectral
peaks are readily visible.
More updates on this
project to come...
Quick link Recent Articles
by Titles
Raman (and
LIBS) Spectroscopy of Pillow Lavas from
the Anaga zone–Tenerife Canary Island
-September
2011
Dimerization and blue light
regulation of PIF1 interacting bHLH proteins in
Arabidopsis-September
2011
Hydrothermal fabrication of well-ordered ZnO
nanowire arrays on Zn foil: room temperature
ultraviolet nanolasers
–September 2011
Battery-operated, argon–hydrogen microplasma on hybrid,
postage stamp-sized plastic–quartz chips for elemental
analysis of liquid microsamples using a portable optical
emission spectrometer-September
2011
Photoluminescence waveguiding in CdSe and CdTe
QDs–PMMA nanocomposite films-
September 2011
NON-DESTRUCTIVE VIS-NIR REFLECTANCE SPECTROMETRY FOR RED
WINE GRAPE ANALYSIS-July
2011
Deposition of ZnO multilayer on LiNbO3 single crystals
by DC-magnetron sputtering-July
2011
Visible Attenuated Total
Reflection (ATR): A New Technique for
High-Strength Pigment Analyses
-
March 2011
Tar analysis from biomass
gasification by means of online fluorescence
spectroscopy-
March 2011
Comparison of
diode-side-pumped Nd:YAG and Nd:YAP laser--March
2011
Identification and Discrimination of Bacterial
Strains by Laser Induced Breakdown Spectroscopy
and Neural Networks-
March 2011
A
novel high-throughput in vivo molecular screen
for shade avoidance mutants identifies a novel
phyA mutation -
March 2011
Comparison of visible and infrared spectrum of
light sources-March 2011
Deactivation of A549 cancer cells in vitro by a
dielectric barrier discharge plasma needle-
March 2011
Fluorescent Illumination with High
Red-to-far-red Ratio Improves Resistance of
Cucumber Seedlings to Powdery Mildew
-
March 2011
Electrochemical texturing of Al-doped ZnO thin films for
photovoltaic applications-February
2011
Accurate color predictability based on a
spectral retardance model of a twisted-nematic
liquid-crystal display -February
2011
Femtosecond OPO for CARS spectroscopy-February
2011
Interferon-[ggr]
links ultraviolet radiation to melanomagenesis
in mice-
January 2011
Kinetic and thermodynamic study of the reaction
catalyzed by glucose-6-phosphate dehydrogenase
with nicotinamide adenine dinucleotide-January
2011
Microbial UV Fluence-Response
Assessment using a Novel UV-LED Collimated Beam
System- December 2010
The potential of alternative
lighting-systems to suppress pre-harvest sexual
maturation of 1+ Atlantic salmon (Salmo salar)
post-smolts reared in commercial sea cages
- December
2010
Aposematic Signal Variation Predicts Male-Male
Interaction in Polymorphic Poison Frog -
Nov 2010
Provitamin D Doped Silica and Polymeric Films:
New Materials for UV Biosensor-
Oct
2010
Nano-Biomimetic
Materials for the Detection of Chemical Agents
in Gases, Aerosols, and Solutions-
Oct 2010
Specific Light-Emitting
Diodes Can Suppress Sporulation of Podosphaera
pannosa on Greenhouse Roses- September
2010
The emerging roles of melanopsin in behavioral
adaptation to light -
August 30, 2010
Skin Lesions Classification with Optical Spectroscopy
SPECTRALLY RESOLVED
SOLAR IRRADIANCE DERIVED FROM METEOSAT CLOUD
INFORMATION -METHODS AND VALIDATION
Extinction
Cross-Section Measurements of Bacillus globigii
Aerosols
Investigation of the Effects of Soil Compaction
in Cotton
Non-destructive measurement of moisture and
soluble solids content of Mazafati date fruit by
NIR spectroscopy
Detection of Fecal/Ingesta Contaminants on
Poultry Processing Equipment Surfaces by Visible
and NIR Reflectance
The
MPSS is a multi-channel process control monitor
used in semi-conductor fabrication and other
real-time process applications.
A field-study of inducible molecular defenses,
ultraviolet radiation, and melanomagenesis in
natural Xiphophorus hybrids
SPECTRAL DIFFERENTIATION BETWEEN COPPER AND IRON
COLORANTS IN GEM TOURMALINES
OH Emission
Spectra of Hybrid Rocket Motors Using PMMA and
HTPB
Synthesis of (SrLaF) FeAs superconducting films
by pulsed laser deposition~ Relationship between
photo excited lights and crystalline of the
films
Agriculture, Food, and Forestry
NON-DESTRUCTIVE VIS-NIR REFLECTANCE SPECTROMETRY
FOR RED WINE GRAPE ANALYSIS
–July 2011
Michael Fadock
–Thesis, University of Guelph
A
novel non-destructive method of grape berry
analysis is presented that uses reflected light
to predict berry composition. The reflectance
spectrum was collected using a diode array
spectrometer (350 to 850 nm) over the 2009 and
2010 growing seasons. Partial least squares
regression (PLSR) and support vector machine
regression (SVMR) generated calibrations between
reflected light and composition for five berry
components, total soluble solids (°Brix),
titratable acidity (TA), pH, total phenols, and
anthocyanins. The reflectance data was
decomposed using principal component analysis (PCA)
and independent component analysis (ICA).
Regression models were constructed using 10x10
fold cross validation subject to smoothing,
differentiation, and normalization
pretreatments. All generated models were
validated on the alternate season using two
model selection strategies: minimum root mean
squared error of prediction (RMSEP), and the
„oneSE
heuristic…Diffuse reflectance spectra for the
composite berry samples were measured with a
portable array spectrometer (Model EPP2000C-100,
StellarNet Inc., Tampa, FL, USA) using the
SpectraWiz® software supplied by the
manufacturer.
Figure
14: 2009-10 study instrumentation. From left to right: A
– Spectrometer, B – Light Source, C – Sample Holder.
Figure
18 Average spectral reflection for 2009, 2010, and
relative difference (left to right). Selected difference
features highlighted at 750, 772, 820, and 850nm.
Photosynthetic Consequences of Late Leaf Spot
Differ between Two Peanut Cultivars with
Variable Levels of ResistanceAugust
2011
MP
Singh, JE Erickson, KJ Boote, BL Tillman,
AHC van
Bruggen, and JW Jones - CROP SCIENCE
(51), 2011
Late leaf spot (LLS), caused by
Cercosporidium personatum (Berk.& Curt.)
Deighton, (telemorph = Mycosphaerella berkeleyi
Jenk.) is among the most widespread and
damaging foliar diseases (Nutter and Shokes,
1995) of peanut (Arachis hypogaea L.) in
the southeastern United States. Pod yield losses
of up to 50% have been reported when fungicides
are not applied (Shokes and Culbreath, 1997).
Consequently, regular and costly fungicide
applications are currently used to minimize
yield losses from LLS (Monfort et al., 2004;
Woodward et al., 2008). In addition, breeding
and selection for improved cultivars with
moderate resistance to leaf spot have recently
been used with integrated disease management
practices to reduce inputs and production costs
(Monfort et al., 2004; Woodward et al., 2008).
However, LLS effects on peanut yield are often
variable and do not always correlate with
cultivar LLS resistance ratings (Singh et al.,
2011). An improved understanding of the effects
of LLS on leaf-level physiological responses
could help to explain these variable yield
responses and result in better identification of
improved cultivars in breeding programs... leaf
chlorophyll. Following extraction, 1 mL of
solution was placed in a quartz cuvette and
absorbance was measured at 647 and 664.5 nm with
a spectropho-tometer(Model BW-VIS, StellarNet
Inc., Tampa, FL).
View PDF.
IMPROVEMENT OF NEW OIL CROPS FOR KENTUCKY-2010
Jamboonsri Watchareewan-Doctoral
Dissertations. Paper 120. University of Kentucky.
Three oil crops, chia (Salvia hispanica
L.), flax (Linum usitatissimum L.), and castor (Ricinus
communis L.), were studied because of their nutritional
and industrial values. Chia and flax are rich in an ω3
fatty acid, α-linolenic acid, and castor is a very high
oil producer and high in a hydroxy fatty acid. Ethyl
methanesulfonate (EMS) and gamma rays were employed to
mutagenize chia seeds to produce early
flowering mutants. The M1 population was grown
and induced to flower by short-day photoperiods. The M2
population was planted in the field in Lexington, KY in
2008. Early flowering plants were found 55 days after
planting while non-mutagenized plants did not produce
any flower buds until the 7th of October, 82
days after planting, at a daylength of 11 hours and 32
minutes. 0.012% of the EMS-treated M2 population and
0.024% of the gamma radiation-treated population
flowered much earlier than the controls. M3 early
flowering mutant lines were able to flower at
photoperiods of 12-15 hours in a greenhouse. Selected
lines produced flower buds on the 7th of July, 47 days
after planting, at a daylength of 14 hours and 41
minutes in the field in Lexington, Kentucky…Light
irradiance was measured by using the F400-VisNIR fiber
optic cable (designed for a sensor) with the instrument
(EPP2000 fiber optic spectrometer from StellarNet Inc.).
View PDF.
The
potential of alternative lighting-systems to suppress
pre-harvest sexual maturation of 1+ Atlantic salmon
(Salmo salar) post-smolts reared in commercial sea cages
–December
2010
E Leclercq, JF Taylor, M
Sprague and H.Migaud – Institute of Aquacultural
Engineering.
The aim of
this study was to compare the efficiency of new
candidate lighting-technologies (50W ‘blue’
light-emitting-diode (B, λmax = 465 nm);
232 W ‘green’ hot cathode, (G, λmax = 546 nm);
400 W ‘red’ tungsten-halogen, (R, λmax = 667
to 740 nm)) against a standard 400 W ‘white’
metal-halide used as control technology (C, broad
spectrum) at suppressing sexual maturation of 1+
Atlantic salmon (Salmo salar) in sea-cages. A
total of seven experimental set-ups were tested on a
commercial-scale in three trials using a standardised
photoperiod regime in the form of continuous
artificial-light (LL) applied from winter to summer
solstice during the second year at sea. The experimental
stocks were raised under an ambient thermal regime that
was similar across all trials.
Fluorescent Illumination with High Red-to-far-red Ratio
Improves Resistance of Cucumber Seedlings to Powdery
Mildew -March
T Shibuya, K Itagaki, M
Tojo, R Endo… - HORTSCIENCE, 2011
We
investigated the effects of fluorescent illumination
with a high red-to-far-red ratio (R:FR) on the
resistance of cucumber (Cucumis sativus) seedlings to
powderymildew fungus (Sphaerotheca cucurbitae; PM).
Seedlings were grown at a photosynthetic photon flux (PPF)
of300mmol_m–2_s–1 provided by fluorescent lampswith
highR:FR light (R:FR =7.0; FLH) or low R:FR light (R:FR
= 1.1; FLL) until cotyledons or the first foliage leaf
were fully expanded. Spores of PM were then inoculated
onto the leaves, and the seedlings were grown for 7 days
(fromcotyledon stage) or 9 days (fromfoliage–leaf stage)
under FLH. The number of PM colonies on FLH seedlings
was 0.80· (cotyledons) and 0.62· (foliage leaves) the
number on FLL seedlings. The reduction on the FLH
seedlings was probably the result of changes in leaf
morphological characteristics such as a thicker
epidermal tissue as a result of the higher R:FR
illumination. The number of PM colonies on cotyledons of
the FLH seedlings was also smaller than that on
seedlings grown under metal-halide lamps providing a
spectrum similar to that of natural light (R:FR = 1.2).
The ratio of red (600 to 700 nm) to far-red (700 to 800
nm) light of FLH was 7.0 and that of FLL was 1.1. The
spectrum of FLH was similar to that of FLL, except in FR
(Fig. 1). The spectra were measured with a spectrometer
(BLK-CXR-SR; StellarNet, Tampa, FL).
View PDF.
Fig. -Light spectra of lamps.
FLH
=
fluorescent lamp with high red-to-far-red ratio (R:FR);
FLL
=
fluorescent lamp with low R:FR; ML = metalhalide lamp
that provides a spectrum similar to that of natural
light. Relative photon fluxes per unit wavelength are
expressed relative to the maximum. The R:FR was
estimated by dividing the total photon flux from red
light (600 to 700 nm) by that from far-red light (700 to
800 nm).
Specific Light-Emitting Diodes Can Suppress Sporulation
of Podosphaera pannosa on Greenhouse Roses-September
2010
A. Suthaparan,
S.
Torre, A. Stensvand,
M. L. Herrero, R. I.
Pettersen, D. M. Gadoury,
. R. Gislerød-
Department of Plant and Environmental Sciences,
Norwegian University of Life Sciences-Norwegian
Institute for Agricultural and Environmental Research-Department
of Plant Pathology and Plant-Microbe Biology, Cornell
University
When rose plants
bearing colonies of Podosphaera pannosa were
placed in a wind tunnel, the number of conidia trapped
was directly proportional to intensity of
daylight-balanced (white) light from 5 to 150 μmol m–2
s–1. Illumination of samples using blue (420
to 520 nm) light-emitting diodes (LEDs) increased the
number of conidia trapped by a factor of approximately
2.7 over white light but germination of conidia under
blue light was reduced by approximately 16.5% compared
with conidia germination under white light. The number
of conidia trapped under far-red (>685 nm) LEDs was
approximately 4.7 times higher than in white light, and
13.3 times higher than under red (575 to 675 nm) LEDs,
and germination was not induced compared with white
light. When mildewed plants were exposed to cycles of 18
h of white light followed by 6 h of blue, red, far-red
light, or darkness, light from the red LEDs reduced the
number of conidia trapped by approximately 88% compared
with darkness or far-red light. Interrupting the above
dark period with 1 h of light from red LEDs also reduced
the number of conidia trapped, while a 1-h period of
light from far-red following the 1 h of light from red
LEDs nullified the suppressive effect of red light. Our
results indicate that brief exposure to red light during
the dark interval may be as effective as continuous
illumination in suppressing powdery mildew in greenhouse
rose plant (Rosa × hybrida).
Read More
Investigation of the Effects of Soil Compaction in
Cotton
S. S. Kulkarni, S. G.
Bajwa, G. Huitink
Soil compaction can cause
yield reductions in cotton (Gossypium hirsutum). This
study investigated the effect of soil compaction on
canopy spectral reflectance, soil electrical
conductivity (EC), and cotton yield. Field experiments
were conducted during 2003-2005 using a completely
randomized block design with four soil compaction
treatments. The treatments were no subsoiling (control);
subsoiled, disked, and bedded (conventional); subsoiled
and compacted (compaction I); and compacted with no
subsoiling (compaction II). Field data were collected on
soil resistance, canopy reflectance, soil EC, and cotton
yield. Comparison of means showed differences between
treatments in reflectance in 2003 and 2004, soil
compaction parameters in 2004 and 2005, and soil EC and
yield in 2005. The depth and thickness of the hardpan
were significantly correlated to green NDVI on 16
September (R2 = 0.53) in 2003. Depth, average resistance
of hard pan, and EC all showed relationships with yield
in 2005. Their combination as independent variables
could explain 65% of the variability in cotton yield in
2005. These results verified that compaction affected
canopy reflectance and reduced cotton yield in Arkansas.
The practical implications of the outcome of this study
are the potential use of EC and canopy reflectance to
infer crop yield and extent of soil compaction. However,
a multi-site and multi-year study is necessary to
confirm this possibility....
same locations. Cotton canopy reflectance was
recorded using a spectroradiometer (BLACK-Comet,
StellarNet, Inc).
View PDF...
Plant Reflectance
Spectral reflectance from plants
can
indicates
plant stress
and predict growth rate
Non-destructive measurement of moisture and soluble
solids content of Mazafati date
fruit by NIR spectroscopy
Seyed Ahmad Mireei, Seyed Saeid Mohtasebi, Reza Massudi,
Shahin Rafiee, Atoosa Sadat
Arabanian, Annachiara Berardinelli-
Department of Agricultural Machinery Engineering,
Faculty of Agricultural Engineering and Technology,
University of Tehran- Laser and Plasma Research
Institute, Shahid Beheshti University,
The potential of
Near-Infrared (NIR) spectroscopy technique was assessed
to predict moisture and soluble solids content of
Mazafati date fruit. Spectral acquisitions were carried
out during four main ripening stages (Kimri, Khalal,
Rutab and Tamr)
using a fast, non-scanning spectrometer in the
interactance mode. Two different preprocessing methods;
vector normalization
and multiplicative scatter correction, and wavelength
regions (900- 1700 nm and 1332- 1641 nm) were used to
build partial
least squares (PLS) regression models. The best
predictive models showed coefficient of determination
(R2) values of 0.980
and 0.966 for the moisture and the soluble solids
content respectively; the relative residual predictive
deviation (RPD) values
were 7.1 and 4.8. NIR spectroscopy appeared to be a good
method for the assessment of maturity of the analyzed
date
variety.
View PDF
A schematic of the SNIR
instrument set up and Raw absorption
spectra (mean value) of Mazafati dates in Kimri, Khalal,
Rutab and Tamr ripening stages
USE OF GROUND-BASED CANOPY REFLECTANCE TO DETERMINE
RADIATION CAPTURE, NITROGEN AND WATER STATUS,
AND FINAL YIELD IN WHEAT
Glen L. Ritchie
We quantified the spectral
reflectance characteristics of hard red spring wheat (Triticum
aestivum cv. Westbred 936) in research plots subjected
to either nitrogen or water stress in a two year study.
Both types of stress reduced ground cover, which was
evaluated by digital photography and compared with ten
spectral reflectance indices. On plots with a similar
soil background, simple indices such as the normalized
difference vegetation index, ratio vegetation index, and
difference vegetation index were equal to or superior to
more complex vegetation indices for predicting ground
cover. Yield was estimated by
ivintegrating the normalized difference vegetation index
over the growing season. The coefficient of
determination (r2) between integrated normalized
difference vegetation index and final yield was 0.86.
Read more...
Typical visible and NIR
plant reflectance. Spectral features at 500 nm, 550 nm,
675 nm, and the red edge (about 690 to 750 nm) are
controlled by chlorophyll concentration, while
reflectance at 970 nm is related to water concentration.
And Using the linear nature of soil reflectance to
eliminate soil background signal using derivatives of
reflectance spectra (right).
Spectrometer mounting design for
summer 2002 tests. A rigid swing arm positioned the
spectrometer over the canopy away from the wheelbarrow.
Detection of Fecal/Ingesta
Contaminants on Poultry Processing Equipment Surfaces by
Visible and NIR Reflectance
Spectroscopy
K. Chao, X. Nou, Y. Liu, M. S. Kim, D. E. Chan, C.-C.
Yang, J. Patel, M. Sharma
Visible and near infrared (NIR) spectra and samples for
laboratory microbial analysis were acquired of fecal
contaminants, ingesta contaminants, and bare processing
equipment surfaces (rubber and stainless steel) in a
commercial
poultry processing plant. Spectra were analyzed in the
visible region of 450 to 748 nm and the NIR region of
920 to 1680 nm and microbial sampling for
Enterobacteriaceae counts (EBC) was conducted for 82
fecal contaminant samples, 59 ingesta contaminant
samples, 40 bare rubber belt areas, and 40 bare
stainless steel areas. Two wavelength band ratios in the
visible and NIR regions were selected for separating
contaminants from equipment areas. Principal component
analysis (PCA) was performed to analyze the spectral
data set and 2 class soft independent modeling of class
analogy (SIMCA) models were developed for comparison
with band ratio classification. Fecal and ingesta
contaminants were difficult to separate from each other
but both were easily differentiated from the equipment
areas. The visible ratio using 518 and 576 nm correctly
classified 100% of contaminant samples and 92.5% of
equipment area samples. The NIR ratio using 1565 and
1645 nm correctly classified 100% of the contaminant
samples and 95% of the equipment area samples.
Microbiological analysis found the highest EBC levels
for fecal contaminants; mean EBC for ingesta
contaminants was significantly lower than that for fecal
contaminants. The high EBC levels for fecal contaminants
indicate that these contaminants should be targeted for
spectral based detection methods for sanitation
monitoring and verification purposes; although their EBC
levels are significantly lower, ingesta contaminants
should also be included due to difficulty of separation
from fecal contaminants.
Download pdf
Two portable battery powered spectrometer systems were
used to collect the reflectance spectra in the visible
(400-900 nm) and NIR (900-1700 nm) regions (fig. 1). For
measuring visible spectra, a EPP2000-CXR (now
BLACK-Comet CXR) spectrometer was used
with an SL1
tungsten-krypton fiber-optic light source. For
measuring NIR spectra, a EPP2000-InGaAs spectrometer (now
RED-Wave Spectrometers) was used
with a duplicate SL1
light source unit and a bifurcated fiber-optic probe
Comparison of visible and near infrared reflectance
spectroscopy for the detection of faeces/ingesta
contaminants for sanitation verification at slaughter
plants
Surface Characterization of Weathered Wood-Plastic
Composites Produced from Modified Wood Flour
James S.
Fabiyi, Armando G. McDonald, and Nicole M. Stark
The effects of weathering on the
surface properties of wood-plastic composites (WPC) were
examined. High-density polyethylene (HDPE) based WPCs
made from modified wood flour (untreated, extractives
free, and holocellulose (delignified) fibers) were
subjected to accelerated (xenon-arc) weathering.
Colorimetery and Fourier-transform infrared spectroscopy
were employed to monitor the color change and surface
chemistries of the weathered WPC surface. The
compositional change that occurred on the WPC surface
was determined using pyrolysis GC-MS analysis. The study
showed that longer exposure time caused higher
oxidation, lower wood lignin and higher plastic content
of the weathered WPC surface. From this study, the use
of holocellulose fibers improved the weathering
performance (color) of WPCs.
Download pdf
Initial high-temperature schedule to reduce drying time
and control kiln brown stain in ponderosa pine shop
lumber
The surface color and lightness of rough
green and dry fleshly planed boards were determined
using a StellarNet
Spectrometers.
Read more...
A
fiber optic sensor measures
percent soluble solids in onions for a big pay
off at market time
Interesting and valuable information is
available in the NIR spectral region for many
agricultural products. This application uses a NIR
spectrometer to measure the percent of soluble solids in
an onion by simply shining a light thru it! This
allows non-destructive determination of a harvest.
Environmental and Ecology
Raman Spectroscopy of Pillow Lavas from the Anaga
zone–Tenerife Canary Island-September
2011
E Lalla, As
Caramazana, As Arrana, et al. -Journal
of the
Spanish Society of
Mineralogy
Some
lava deposits have been reported on Mars by
Martinez-Alonso et al (2008), showing similar
characteristics to those of terrestrial pillow lavas.
Pillow Lavas are an unequivocal sign of volcanism in an
aqueous environment. Pillows are found in a wide variety
of shapes including near-spherical bulbous pillows,
flattened pillows, elongate and tubular pillows, and
trapdoor pillows. They are probably the most abundant
lava structural type on Earth. However, this kind of
structure shares a concentric geometry and large central
cavities, butthey have differences in mineralogy, on the
degree of crystallization, and the jointing. The main
reason is that the interiors cool more slowly than the
quenched glass rind, being more crystalline. Progressive
crystallization at slower cooling rates toward the
interior produces a variety of rock textures, and the
interiors of large pillows may be almost entirely
crystalline (Kenish et al.,1998). Studying and
understanding the pillows lavas could help us to
understand the past of Mars... The detection was
performed with a CCD Andor DV420A- OE-130. Furthermore
XRD (with XRD diffractometer Philips PW1710), IR-
Spectroscopy (PerkinElmer Spectrum 100 FT-IR
spectrometer) and LIBS (Porta-Libs from Stellar Net)
were used.
View PDF.
fig 5. Laser Induced
Breakdown Spectrometry of Pillow Lava Sample. On the
Spectra is only shown the most intense peaks. (1) Brown
External Face (2) White External Face (3) Red-Brown
Internal Face
Responses of the blister beetle Hycleus apicicornis to
visual stimuli-April
2011
LN LEBESA,
ZR KHAN, A HASSANALI… - Physiological Entomology
Insect
attraction to host plants may be partly mediated by
visual stimuli. In the present study, the responses of
adult Hycleus
apicicornis(Guér.)
(Coleoptera: Meloidae) to plant models of different
colours, different combinations of two colours, or three
hues of blue of different shapes are compared. Single-colour
models comprised the colours sky blue, bright green,
yellow, red, white and black. Sky blue (reflecting light
in the 440–500 nm region) is the most attractive,
followed by white, which reflects light over a broader
range (400–700 nm). On landing on sky blue targets,
beetles exhibit feeding behaviour immediately. When
different hues of blue (of different shapes) are
compared, sky blue is preferred over turquoise, followed
by dark blue, indicating that H.
apicicornis is
more attracted to lighter hues of blue than to darker
ones. No significant differences are found between the
three shapes (circle, square and triangle) tested,
suggesting that reflectance associated with colour could
be a more important visual cue than shape for host
location by H.
apicicornis.
The preference ofH.
apicicornis for
sky blue can be exploited in designing an attractive
trap for its management.The
reflectance spectra of the coloured inks on white paper
and of the white paper on which they had been printed,
were measured using a Stellarnet EPP2000C
spectroradiometer (Stellarnet Inc., Oldsmar, Florida;
calibrated to an operating range of 300–850 nm).
View PDF.
Aposematic Signal Variation Predicts Male-Male
Interaction in Polymorphic Poison Frog-
Nov 2010
Laura Crothers,
Eben Gering, Molly
Cummings- International Journal of
Organic Evolution
Many species use conspicuous “aposematic” signals to
communicate unpalatability/unprofitability to potential
predators. Although aposematic traits are generally
considered to be classic examples of evolution by
natural selection, they can also function in the context
of sexual selection, and therefore comprise exceptional
systems for understanding how conspicuous signals evolve
under multifarious selection. We used males from a
highly territorial poison frog species in a dichotomous
choice behavioral test to conduct the first examination
of how aposematic signal variation influences male–male
interactions. Our results reveal two behavioral
patterns: (1) male dorsal brightness influences the
behaviors of male conspecifics such that males approach
and call to brighter males more frequently and (2) a
male's dorsal brightness predicts his own behavior such
that bright males approach stimulus frogs faster, direct
more calls to bright stimulus frogs, and exhibit lower
advertising call pulse rates (a fitness-related trait).
These findings indicate the potential for sexual
selection by male–male competition to impact aposematic
signal evolution.
In Vitro Model of Vitamin D Synthesis by UV
Radiation in an Australian Urban Environment
-Nov
2010
Alex Mc Kinley, Monika
Janda, Josephine Auster, Michael Kimlin
Vitamin D, an important constituent of
human health, is produced through exposure of human skin
to short wave (280–315 nm) ultraviolet radiation (UV).
We aimed to establish whether an urbanized environment
with tall buildings in close proximity (an ‘urban
canyon’) significantly reduced the capacity of sunlight
to synthesize vitamin D, when compared to a typical
suburban area (∼2.5 km away); and to investigate the
association of UV and vitamin D production with
pollution, temperature, and humidity. Measurements of
ambient UV (295–400 nm) (using a portable
photometer/radiometer and detector) and synthesized
vitamin D (from an in vitro model) were taken
regularly at urban and control sites over three months
in Brisbane, Australia. During a typical 20-minute
measurement, urban and control sites received 0.26 and
1.03 W/m2 mean total UV respectively
(p<0.001), and produced 0.12 and 0.53 μg/mL mean vitamin
D (p<0.001). Pollution, temperature and humidity were
not associated with UV or vitamin D production. This
demonstrates a large difference in vitamin D synthesis
between an urban canyon and a nearby control site.
Although the results cannot be directly applied to
humans, they emphasize the need for further study of
human vitamin D production in urban environments.
SPECTRALLY RESOLVED SOLAR IRRADIANCE DERIVED FROM
METEOSAT CLOUD INFORMATION -METHODS AND VALIDATION
Jethro Betcke, Tanja Behrendt, Jan Kühnert, Annette
Hammer, Elke Lorenz, Detlev Heinemann
Carl von Ossietzky University Oldenburg, Energy and
Semiconductor Laboratory, Energy Meteorology Group
The varying spectral distribution of the
terrestrial irradiance can cause significant differences
between the actual and the rated efficiency of solar
cells. To account for this effect it is necessary to
calculate the weighted irradiance which depends on the
solar cell spectral response and on the spectral
distribution of the irradiance. Because ground based
spectral measurements are sparse, satellite based
spectral data can provide a good alternative. In this
work we have compared two approaches. The SOLIS method
can calculate both broadband and spectrally resolved
terrestrial solar irradiance from satellite data. The
clear sky module of SOLIS is based on a partial
parametriation of radiative transfer calculations, and
uses atmospheric data from climatologies or satellite
based methods. The cloud module is based on empirical
relationships between the cloud albedo values determined
from Meteosat visual channels and the cloud
transmittance. In parallel we developed a simpler
empirical method, that can be more easily implemented in
photovoltaic modeling software. It is based on principal
component analysis of measured spectrally resolved
irradiance and empirical relationships between the
principal components and satellite derived clear sky
index and sun elevation. Both methods have been
validated using the same ground measured data from
Stuttgart Germany. The
weighted irradiance has been used as metrics to compare
the results of the models. It was found that the use of
both models gave a significant improvement compared to
the use of a constant AM1.5 spectrum. The use of the
empirical model resulted in lower bias values, the use
of SOLIS resulted in lower
RMSE values. Apparatus used StellarNet
BLACK-Comet,
RED-Wave InGaS.
View PDF…
The effect of metal halide and novel green cathode
lights on the stress response, innate immunity, eye
structure and feeding activity of Atlantic cod, Gadus
morhua L.
-2011
M Cowan, A Davie… -
Aquaculture Research, 2011
High-intensity constant lighting is routinely used for
photoperiod manipulation in the aquaculture industry in
order to prevent early maturation. The potential welfare
impacts of this technology, however, have not been
extensively studied to date, and with the implementation
of more efficient narrow bandwidth lighting technologies
(cathode, light-emitting diodes), definitions of
species-specific sensitivities are becoming essential.
The objective of this study was to investigate the
impact of traditional metal halide (MH) and novel green
cathode lighting on the welfare (stress response, innate
immunity, retina structure, feeding activity) and light
perception of Atlantic cod. The results indicated that
although acute responses to light were observed, there
were no clear signicant long-term effects of any of the
lighting treatments on the stress levels (plasma
cortisol, glucose), innate immune function (lysozyme
activity), retina structure and population feeding
activity (acute decline under all light treatments, most
pronounced in
￠sh
exposed to higher illumination, but normal feeding
activity was resumed within 8 days following light
onset). Regarding light perception, interestingly, even
when subjected to high intensity constant lighting (MH
mean tank intensity: 16.6Wm_2), cod still demonstrated a
day-night rhythm in melatonin release, which suggests
perception of the overlying ambient photoperiod....
Spectral content was recorded using a portable
spectroradiometer (Model BLACK-Comet,
Stellarnet, Tampa, FL, USA). Following acclimation, fish
were randomly assigned to one of five light treatments
(duplicated) for 4 weeks.
View PDF.
Figure:
Normalized spectral profiles for (a) control fluorescent
light, (b) cathode light and (c) metal halide light
units.
A field-study of inducible molecular defenses,
ultraviolet radiation, and melanomagenesis in natural
Xiphophorus hybrids
Seth W.
Coleman & Zachary W. Culumber & Ashley Meaders &
Jennifer Henson & Gil G. Rosenthal
Ultraviolet radiation—the primary natural pollutant
affecting melanomagenesis—may represent a widespread
ecological stressor for many fishes, and yet the
relationship between UV-exposure and stress has not been
investigated in natural fish populations. Recent
lab-based studies have sought to characterize the
relationship between tumorigenesis and the induction of
molecular defenses, such as heat shock proteins. Here we
show that ultraviolet radiation and heat shock protein
gene expression explain a significant amount of the
variation in hyper-melanization—the phenotypic precursor
to melanoma—in wild hybrids of Xiphophorus, laboratory
models in cancer research.Our results suggest exposure
to UV radiation causes stress which induces molecular
defense mechanisms, which in turn may facilitate
tumorigenesis in natural fish populations. Studies of
laboratory-based model organisms in natural settings,
like this one, may provide important insights into
ecological and evolutionary relationships obscured in
controlled laboratory environments. We hope that ours is
only the first of many studies to investigate the such
relationships between environmental stress,
stress-induced molecular defenses, and cancer in fishes.View
PDF...
The relationship between incident
solar irradiance across the UV range (units are divided
by the interval—101 nm) and melanization among
populations
Female
Preferences for Aposematic Signal Components in
a Polymorphic Poison Frog
Martine E. Maan and Molly
E. Cummings, University of Texas at
Austin, Integrative Biology
Aposematic signals may be
subject to conflicting selective pressures from
predators and conspecifics. We studied
female preferences for
different components of aposematic coloration in
the polymorphic poison frog Oophaga pumilio
across several phenotypically
distinct populations.
Male reflectance spectra. Curves
represent average reflectances
of all males used in the experiments. Gray areas
indicate
between-individual variation (standard errors). Left
panels
are dorsal reflectance spectra; right panels are ventral
reflectance
spectra.
A private ultraviolet channel in visual communication
Molly E. Cummings, Gil G.
Rosenthal and Michael J. Ryan- Section of Integrative
Biology, University of Texas, Austin- Boston University
Marine Program
Although private
communication is considered an important diversifying
force in evolution, there is little direct behavioural
evidence to support this notion. Here, we show that
ultraviolet (UV) signalling in northern swordtails (Xiphophorus)
affords a channel for communication that is not
accessible to their major predator, Astyanax mexicanus,
the Mexican tetra. Laboratory and field behavioural
experiments with swordtails (X. nigrensis) and predators
(A. mexicanus) demonstrate that male UV ornamentation
significantly increases their attractiveness to females
but not to this predator, which is less sensitive to UV.
UV reflectance among swordtail species correlates
positively with tetra densities across habitats, and
visual contrast estimates suggest that UV signals are
highly conspicuous to swordtails in their natural
environment. Cross-species comparisons also support the
hypothesis that natural selection drives the use of UV
communication. We compared two species, one with high
(X. nigrensis) and one with low (X. malinche) Mexican
tetra densities. Xiphophorus nigrensis males reflect
significantly more UV than X. malinche, exhibit
significant UV sexual dimorphism, and UV is a salient
component of the sexual communication system. In X.
malinche, however, males reflect minimally in the UV,
there is no UV sexual dimorphism, and UV does not play a
part in its communication system.
Mean spectral reflectance
of Xiphophorus nigrensis
(a), and X. malinche (b), males (black lines) and
females
(grey lines) for caudal (circles), ventral (diamonds),
and
horizontal stripe (squares) body areas and male sword
(solid
line). The dashed line at 400 nm represents the upper
boundary for UV wavelengths.
Remote Sensing
Monitoring- Tallapoosa Watershed
John Glasier,
Luoheng Han
Hyperspectral Reflectance Measurements of
Chlorophyll Concentration and
Related Water Quality Predictors
Download pdf
StellarNet extreme
Portability-EPP2000C is now called the
BLACK-Comet and
does not require external power (only your computers
USB)!
Influence of plumage colour on prey response:
does habitat alter heron crypsis to prey?
M. CLAY GREEN & PAUL L. LEBERG
The foraging strategies of wading birds may be
influenced by their degree of crypsis to aquatic
prey. White
plumage has been hypothesized to be adaptive for
herons hunting in open water habitats.
We tested this hypothesis with laboratory and field experiments
with multiple prey species.
The foraging strategies of wading birds
may be influenced by their degree of crypsis to
aquatic prey. White
plumage has been hypothesized to
be adaptive for herons hunting in open
water habitats. We
tested this hypothesis
with laboratory and field experiments with
multiple prey species.Download
pdf
SPECTRAL DIFFERENTIATION BETWEEN COPPER AND IRON
COLORANTS IN GEM TOURMALINES
Paul B. Merkel and
Christopher M. Breeding
The authors used Vis-NIR spectral
measurements combined with LA-ICP-MS data to
investigate the usefulness of absorption spectra
for differentiating between copper and iron as
sources of greenish blue coloration in gem
tourmaline. While both Cu2+ and Fe2+ produce
absorption bands with maxima near 700 nm, Cu2+
also has a strong band with a maximum near
900–925 nm, where absorption due to Fe2+ is
typically at a minimum. In addition, Vis-NIR
spectroscopy successfully identified Cu in
pink/purple and violet stones that could be
candidates for heat treatment. For the blue,
green, and violet Cu-bearing tourmalines of
pale-to-moderate color intensity in this study,
weight percent of CuO could be estimated from
the absorbance at 900 nm. This relatively
inexpensive identification method may prove to
be a valuable screening tool for Cubearing
tourmaline.
View PDF...
These Vis-NIR absorption
spectra (collected with the EPP2000
spectrometer- now called the
BLACK-Comet) are from green tourmalines
colored primarily by Cu2+ (G3), Fe2+ (G2, G3),
or V3+ (G8).
Benchtop vs. StellarNet miniature spectrometers-
For each sample, we determined specific gravity
hydrostatically and measured refractive indices
using a standard gemological refractometer.
Vis-NIR spectra were collected with two
different spectrometers. We analyzed most of the
larger samples using a Perkin-Elmer Lambda 950
spectrometer equipped with a 150 mm integrating
reflectance sphere, in the range 350–1150 nm.
The gem was held (~5° from normal) in the jaws
of center-mount sampling module PELA-9038, and
the beam was directed through the table and
reflected back off the pavilion facets. Smaller
samples (<1 cm) could not be reliably measured
with this configuration, because they did not
completely intercept the beam. They were instead
measured using a StellarNet EPP2000-CXR CCD
array spectrometer with an SL1 tungsten-krypton
light source and a R400-7-VisNIR bifurcated
fiberoptic reflectance probe, in the range
400–900 nm. These smaller gems were usually
placed table-down on a white reflective
standard. The small tip of the fiber-optic
probe, providing both the analyzing beam and the
collection of transmitted light, was placed near
the culet and aimed toward the table. The beam
reflected off the white standard back through
the table to the probe. Intensity measurements
with and without the gem in place allowed
absorbance to be determined. For both
techniques, the approximate path of the
analyzing beam consisted essentially of a dual
traverse between the table and the culet. Both
spectrometers provided absorbance vs. wavelength
directly (uncorrected for path length). Spectral
maxima of gems measured on both spectrometers
were identical, and absorbance values were
within ~10%.
Spectral
Signatures of surface materials in pig buildings
Guoqiang Zhang and
Jan S. Strom- Danish Institute of Agricultural Sciences
Spectral Signatures of the
reflectance of visual and near infrared
radiation are used to make statistically
significant discrimination between clean and
dirty pig building areas
Monitoring Birds- Black Phoebes
Dr. Esteban Fernández-Juricic,
Assistant Professor, Department of Biological Sciences,
Cal State Long Beach
For a bird to
survive, it must be able to successfully find and eat
food items. Many factors can affect the ability of the
bird to find food such as the habitat it lives in, the
abundance of food, or how its visual system interprets
images. Birds are generally considered to have very
good color vision. In this study we explored how the
Black Phoebe’s (a small bird that is a sit-and-wait
predator) vision, the reflectance of prey items and the
background, and irradiance interacted to change how the
bird looked for food items.
Read More...
Physics
Hydrothermal fabrication of well-ordered ZnO nanowire
arrays on Zn foil: room temperature ultraviolet
nanolasers–September
2011
JY Kim, H Jeong, and DJ Jang… - Journal
of Nanoparticle Research
Well-ordered nanowires of the hexagonal
wurtzite ZnO having an average diameter of 80 nm, a
typical length of 12 μm, and a mean packing density of
7.5 nanowires μm−2 have
been directly grown on Zn foil in a preferred [0001]
direction by a hydrothermal process and employed for
room temperature ultraviolet nanolasers. The lasing
action of arrayed ZnO nanowires has been observed from
370 to 400 nm with threshold irradiance of 25 kW cm−2.
Photoluminescence decays biexponentially: the fast
component is attributed to free-exciton decay, and the
slow one is to bound-exciton decay. The amplitude of the
fast component increases whereas its lifetime decreases
with the increment of threshold irradiance, suggesting
that ZnO nanowire arrays undergo a change in the lasing
mechanism from exciton–exciton scattering to
electron–hole plasma recombination.
... Absorption spectra were measured using a StellarNet
EPP2000C UV–VIS reflectance
spectrometer, and Raman spectra were measured
using an OLYMPUS BX41 confocal microscope Raman system
equipped with a Dynamic
Laser LS300 Ar laser as the excitation source.
View PDF.
Design Principles of FRET-Based
Dye-Sensitized Solar Cells
with Buried Quantum Dot Donors-June-
2011
S
Itzhakov, S Buhbut, E Tauber, T Geiger, A Zaban, and D
Oron - Advanced Energy Materials
In this
article, the physics of FRET is demonstrated for an
architecture of dye-sensitized solar cells, in which the
quantum dot “antennas” that serve as donors are
incorporated into the solid titania electrode, providing
isolation from electrolyte quenching, and potentially
increased photostability. The energy transferred to the
dye acceptor from the quantum dot donor, in addition to
the direct light absorption by the dye, finally induce
dye excitation and electron injection to the metal oxide
semiconductor electrode. We use time-resolved
photoluminescence measurements to directly show
achievement of FRET efficiencies of up to 70%,
corresponding to over 80% internal quantum efficiency
when considering radiative energy transfer as well. The
various parameters governing the FRET efficiency and the
requirements for high efficiency FRET-based cells are
discussed. Since both buried donors inside the electrode
and donors solubilized in the electrolyte have both been
shown to achieve high energy transfer efficiencies, and
as the two methods take advantage of different available
volumes of the electrode to introduce donors providing
the excess absorption, synergy of the two methods is
highly promising for achieving panchromatic absorption
within a thin electrode...The
absorption and emission spectra of both the QDs and the
SQ02 dye molecules were recorded using a JASCO V-630 and
a StellarNet UV-VIS-NIR fiber optic spectrometers and
are shown in Figure 6. SQ02 solution shows an absorption
max at 655 nm.
View PDF.
Effect of fabrication parameters on
morphological and optical properties of highly doped
p-porous silicon-June
2011
M Zare, A Shokrollahi and
F Seraji- Applied Surface Science, 2011
Porous
silicon (PS) layers were fabricated by anodization of
low resistive (highly doped) p-type silicon in HF/ethanol
solution, by varying current density, etching time and
HF concentration. Atomic force microscopy (AFM) and
field emission scanning electron microscope (FESEM)
analyses were used to investigate the physical
properties and reflection spectrum was used to
investigate the optical behavior of PS layers in
different fabrication conditions. Vertically aligned
mesoporous morphology is observed in fabricated films
and with HF concentration higher than 20%. The
dependence of porosity, layer thickness and rms
roughness of the PS layer on current density, etching
time and composition of electrolyte is also observed in
obtained results. Correlation between reflectivity and
fabrication parameters was also explored. Thermal
oxidation was performed on some mesoporous layers that
resulted in changes of surface roughness, mean height
and reflectivity of the layers...
The reflection spectrum was evaluated by Stellar Net
EPP2000-HR High Resolution Miniature Spectrometer... For
this purpose, we take a halogen – tungsten lamp as a
light source and a Stellar Net EPP2000-HR Miniature
Spectrometer with 5 Å resolution. View
PDF.-
Photoluminescence waveguiding in CdSe and CdTe QDs–PMMA
nanocomposite films-September
2011
I Suárez, H Gordillo, R
Abargues, S Albert, and J M Pastor - Nanotechnology,
2011
In this paper, active planar waveguides based on the
incorporation of CdSe and CdTe nanocrystal quantum dots
in a polymer matrix are demonstrated. In the case of
doping the polymer with both types of quantum dots, the
nanocomposite film guides both emitted colors, green
(550 nm, CdTe) and orange (600 nm, CdSe). The optical
pumping laser can be coupled not only with a standard
end-fire coupling system, but also directing the beam to
the surface of the sample, indicating a good absorption
cross-section and waveguide properties. To achieve these
results, a study of the nanocomposite optical properties
as a function of the nanocrystal concentration is
presented and the optimum conditions are found for
waveguiding.
... When PL experiments (section 3.3) have been carried
out a cylindrical lens has been used to focus this line
into a point to fiber optics connected to a spectrograph
(StellarNet EPP2000). Propagation properties depend
strongly on the filling factor of the active layer.
View PDF.
Surface modification of polytetrafluoroethylene film
using single liquid electrode atmospheric-pressure glow
discharge-June
2011
L
Zhou, GH Lü, W Chen, H Pang, GL Zhang, and SZ Yang-
Chinese Physics B, 2011
Polytetrafluoroethylene films are treated
by room temperature helium atmospheric pressure plasma
plumes, which are generated with a home-made single
liquid electrode plasma device. After plasma treatment,
the water contact angle of polytetrafluoroethylene film
drops from 114° to 46° and the surface free energy
increases from 22.0 mJ/m2 to
59.1 mJ/m2. The optical emission spectrum
indicates that there are reactive species such as O+2,
O and He in the plasma plume. After plasma treatment, a
highly crosslinking structure is formed on the film
surface and the oxygen element is incorporated into the
film surface in the forms of —C—O—C—, —C=O, and —O—C=O
groups. Over a period of 10 days, the contact angle of
the treated film is recovered by only about 10°, which
indicates that the plasma surface modification is stable
with time ... free
energy of PTFE samples and its polar and dispersive
components were calculated with the measured contact
angles of the two liquids using the Owens- Wendt
method.[31−33] The
optical emission
spectrum of APGD plume was investigated by Stellarnet
EPP- 2000C.
View PDF.
TiO2 absorption and scattering
coefficients using Monte Carlo method and macroscopic
balances in a photo-CREC unit-August
2011
J Moreira, B Serrano, A
Ortz, and H de Lasa - Chemical Engineering Science, 2011
The radiation field inside photocatalytic reactors can
be predicted by solving the Radiative Transfer Equation
(RTE). From the solution of the RTE, the local
volumetric rate of energy absorption (LVREA) can
also be obtained. This LVREA is
an important parameter in photocatalytic reactor design,
energy efficiency assessments and kinetic studies of
photocatalytic reactions. However, when solving the RTE,
two optical parameters are needed: (1) the absorption
and scattering coefficients and (2) the phase function.
In the present study, the Monte Carlo (MC) method along
with an optimization technique is shown to be effective
in predicting the wavelength-averaged absorption and
scattering coefficients for three different TiO2 powders.
To accomplish this, the LVREA and
the transmitted radiation (Pt) in a
Photo-CREC annular photoreactor have to be determined by
using a macroscopic balance. The optimized coefficients
are calculated ensuring that they comply with a number
of physical constrains, falling in between bounds
established via independent criteria. The optimization
technique is demonstrated by finding the absorption and
scattering coefficients for three different
semiconductors that best fit the experimental values
from the macroscopic balance minimizing the
least-squared error of objective functions for the LVREA and Pt.
The proposed approach is a general and promising one,
not being restricted to reactors of concentric geometry,
specific semiconductors and/or particular photocatalytic
reactor unit scale
... tubing (refer to Figure
4). The Photo-CREC Water II photocatalytic reactor has
seven 1.1-cm in diameter circular windows equally spaced
made of fused silica (number 4 in Figure 3). Radiation
measurements were made at each window position using a
StellarNet EPP2000C-25.
View PDF.
Optically thin composite resonant
absorber at the near-infrared band: a polarization
independent and spectrally broadband configuration
–July
2011
KB Alici,
AB Turhan, CM Soukoulis, and E Oz- Optics Express, 2011
We
designed, fabricated, and experimentally characterized
thin absorbers utilizing both electrical and magnetic
impedance matching at the near-infrared regime. The
absorbers consist of four main layers: a metal back
plate, dielectric spacer, and two artificial layers. One
of the artificial layers provides electrical resonance
and the other one provides magnetic resonance yielding a
polarization independent broadband perfect absorption.
The structure response remains similar for the wide
angle of incidence due to the sub-wavelength unit cell
size of the constituting artificial layers. The design
is useful for applications such as thermal photovoltaics,
sensors, and camouflage. ...The signal was measured by
using a StellarNet Red Wave NIR spectrometer at the
infrared regime (900 nm–1700 nm).
View PDF.
Fig. 5. Simulated absorption response of the SRR based
metamaterial absorber for several incidence angles.
J Li, Q Chen, G Feng, W Wu, D Xiao, and J
Zhu- Ceramics International, 2011
Nd-doped YAG ceramics were
fabricated by the solid-state reaction and two-step
vacuum sintering method. It is found that the samples
exhibit pore-free and homogeneous microstructures and
their transparency is up to 84.98% at the visible and
near-infrared band and 87% in the mid-infrared wave
range. The absorption cross section of 0.3% Nd:YAG at
808 nm is 5.47 × 10−20 cm2, while
the emission cross section at 1064 nm is 4.66 × 10−19 cm2.
The different transmittances of the samples depending on
the sintering conditions were also discussed...
The fluorescence spectra of the specimens excited by an
808 nm laser diode (LD) were measured by a spectrograph
(EPP2000/EPP2000C, StellarNet, USA). All the optical
spectrums were measured at room temperature. 3. Results
and discussion.
View PDF.
Deposition of ZnO multilayer on LiNbO3 single crystals
by DC-magnetron sputtering-July
2011
M Shirazi, MT
Hosseinnejad, A Zendehnam, Z Ghorannevis, and M
Ghoranneviss- Applied Surface Science, 2011
Zinc oxide (ZnO) thin films
were deposited on LiNbO3 (LN)
single crystals with 200 nm thicknesses by three
different ways, where coating of zinc (Zn) film was
followed by thermal oxidation for four, two, and one
steps with 50, 100, and 200 nm thicknesses repeatedly.
Sample, which was produced at 4-step of deposition and
oxidation of Zn layer, showed high transmittance and low
structural defect due to a lower photoluminescence
intensity and Urbach energy. Average grain size in X-ray
diffraction (XRD), scanning electron microscopy (SEM)
micrograph, and atomic force microscopy (AFM) images for
multilayer of ZnO was lower than monolayer of ZnO thin
films. Applying multilayer coating technique leads to
decrease of surface roughness and scattering on light on
surface and fabrication of LiNbO3waveguides
with lower optical loss
... Photoluminescence (PL) spectra, (Stellar Net
EPP-200) were taken at room temperature under 340 nm
xenon lamps as the excitation source. The ZnO film
structure was studied by X-ray diffraction (XRD), (X'pert
PW 3373) using Cu Kα (λ = 1.54 Å) radiation.
View PDF.
Runaway electron preionized diffuse discharges in
atmospheric pressure with a point-to-plane gap in
repetitive pulsed mode-April
2011
T Shao, C
Zhang, Z Niu, P Yan, VF Tarasenko… - Journal of Applied
Physics, 2011
This paper
presents the results of the experimental studies of a
pulsed discharge in atmospheric pressure air in an
inhomogeneous electric field for various parameters of
voltage pulses. It is shown that in a wide range of
experimental conditions, including those with a positive
electrode of small curvature radius, a diffuse discharge
is ignited in the gap. In particular, a diffuse
discharge is ignited at a pulse repetition frequency of
1 kHz and a voltage pulse
amplitude of 25 and 40 kV across a high-resistance load.
With voltage pulses of ∼ 220 kV in amplitude and low
repetition frequencies, an extended (70 cm) diffuse
discharge is observed in gaps of 13–40 mm. It is
confirmed that the diffuse form of discharges in an
inhomogeneous electric field at increased pressures is
attributed to the generation of runaway electrons and
x-rays...
The radiation spectrum of the discharge was recorded
using a spectrometer (StellarNet, EPP2000-C25). ...
Figure shows the radiation spectrum of the diffuse
discharge plasma in air obtained by a StellarNet
EPP2000-C25 spectrometer with a 2-mm gap.
View PDF.
Pulsed cathodoluminescence of diamond, calcite,
spodumene, and fluorite under the action of
subnanosecond e beam-
Nov
2010
E. Kh. Baksht, A. G.
Burachenko and V. F. Tarasenko-
Technical Physics Letters
Amplitude and temporal characteristics of pulsed
cathodoluminescence (PCL) of diamond (natural and
synthetic), calcite, spodumene, and fluorite have been
studied at a temporal resolution of
0.3 ns. The PCL was generated by electron beam
pulses with a full width at half maximum (FWHM) of 0.1,
0.25, and 0.65 ns. The PCL spectra have been measured
for the emission induced by 0.1- and 0.25-ns pulses at a
beam current density of 90
A/cm2
... It was
demonstrated that the PCL can be generated by supershort
avalanche electron beams (SAEBs)
generated in gas diodes filled with air at atmospheric
pressure. Previously, we have
used a commercial small size
BLACK-Comet spectrograph (StellarNet Inc.)
...
Provitamin D Doped Silica and Polymeric Films: New
Materials for UV Biosensor
–Oct
2010
TN Orlova, IP
Terenetskaya, AM Eremenko,
N. I. Surovtseva2
Institute of Physics and Chuiko Institute of Surface
Chemistry, National Academy of Sciences of Ukraine
The
original technologies of growing silica films,
impregnated with 7-dehydrocholesterol (provitamin D3) on
quartz substrates and free transparent films on the
basis of polyvinyl alcohol and polyvinyl butyral have
been developed. Provitamin D photoisomerization in the
films under UVB irradiation was investigated by UV
absorption spectroscopy. Remarkable changes in the
absorption spectrum of 7-DHC were observed in silica and
polyvinyl alcohol films as compared with ethanol
solution, only in polyvinyl butyral film the spectrum
was very nearly, while the spectral kinetics of 7-DHC
photoisomerization in all the films was different from
ethanol. We suggest that several films have potential as
UV dosimeters to measure accumulated ‘antirachitic’ UV
dose in the same manner as erythemic UV dose is
measuredby commonly used polysulphone film.
Spectral irradiance of the
UV lamp at the sample distance 8 cm was determined using
calibrated spectrometer BLACK-Comet
(StellarNet, Inc).
View PDF…
Figure-
Transformation of the 7-DHC absorption spectrum
in ethanol (a), PVB film (b), silica film (c) and PVA
film (d) upon irradiation with
the EL-30 UV lamp.
Synthesis of (SrLaF) FeAs superconducting
films by pulsed laser deposition~ Relationship between
photo excited lights and crystalline of the films~
Satoshi
Kurumi, Yoshiki Takano, and Kaoru Suzuki-Department of
Electrical Engineering and Department of Physics
We have tried to prepare superconducting
(SrLaF)FeAs thin films by the photo excited pulsed laser
deposition (PE-PLD). Theexcitation of As Sr and La atoms
are observed in the luminescence spectra of the ablation
plum during the deposition. The peakintensities due to
above excitations become large when the ultra violet
rays are irradiated to the plums. The X-ray
diffractionmeasurements show that some oriented peaks of
(SrLaF)FeAs are observed in the films produced by the
PLD with ultra violet rays.These results indicate that
the excitation by the ultra violet rays has an effective
role in the growth of the superconducting thin films....
The luminescence of the ablation plums are measured by
using a StellarNet BLUE-Wave
spectrometer. As the optical fiber for the spectroscopic
measurement is not used at hightemperature, the
luminescence spectrum of the plum excited by infrared
ray cannot be measured. ...
Femtosecond OPO based on LBO pumped by a
frequency-doubled Yb-fiber laser-amplifier system for
CARS spectroscopy
–February 2011
C Cleff, J Epping, P
Gross and C. Fallnich - Applied Physics B: Lasers and
Optics
We present detailed investigations of a femtosecond
green-pumped optical parametric oscillator (OPO) based
on lithium triborate. As pump source, a
frequency-doubled Yb-fiber laser-amplifier system is
used. The OPO generates signal pulses tunable over a
spectral range from 780 to 940 nm and idler pulses
tunable from 1630 to 1190 nm. More than 250 mW are
generated in the signal beam and more than 300 mW in the
idler beam. Without dispersion compensation chirped
signal pulses with a pulse duration between 100 and 250 fs
are measured. Using this system for coherent anti-Stokes
Raman scattering spectroscopy, vibrational resonances
between 1110 and 6760 cm−1 can
be excited. Due to the chirped pulses, a spectral
resolution of 100 cm−1 is
achieved, which is 2.5 times higher compared to an
excitation with time-bandwidth limited pulses.
... The emission wavelengths were measured with a
grating-based spectrometer (Stellarnet BLUE-Wave,0.5-nm
resolution), and for each data point of the temperature
tuning curve, the signal output power was optimized over
the res- onator length for each crystal temperature.
JL
Martinez, P Garcia-Martinez, MM Sanchez-Lopez and
Ignacio Moreno - Optics Communications, 2011
In this work
we present the application of a simple physical model to
accurately predict the broadband spectral transmittance
and colorimetric properties of a twisted-nematic liquid
crystal display (TNLCD). We spectroscopically calibrate
the retardance parameters to evaluate the spectrum of
the light transmitted by a TNLCD sandwiched between two
linear polarizers. When the TNLCD is illuminated with a
broadband light source, the full spectrum can be
predicted as a function of the addressed gray level for
any arbitrary orientation of the polarizers. Thus, the
color of the transmitted light can be also be estimated
with very good accuracy. As an example, a polarizers'
configuration is shown that yields, without using color
filters, a relatively large color gamut compared to the
standard configuration. Experimental results confirming
the validity of such predictions are presented, both on
the measured spectral responses as well as on the
trajectories at different chromatic diagrams
... Fig. 2(a) shows a
picture of the setup. The light transmitted by the
system is focused on the back focal plane of a
converging lens, where it is captured by a fiber to be
analyzed with a calibrated UV-visible spectro-radiometer
(Stellar-Net, model EPP-2000).
Shape and Refractive Index Recovery from Single-View
Polarisation Images-
June 13, 2010
Cong Phuoc Huynh,
Antonio Robles-Kelly, Edwin
Hancock- School of
Engineering, Australian National University-National
ICT Australia- Department of Computer Science,
University of York
In this paper, we propose an approach to the problem of
simultaneous shape and refractive index recovery from
multispectral polarisation imagery captured from a
single viewpoint. The focus of this paper is on
dielectric surfaces which diffusely polarise light
transmitted from the dielectric body into the air. The
diffuse polarisation of the reflection process is
modelled using a Transmitted Radiance Sinusoid curve
and the Fresnel transmission theory. We provide a method
of estimating the azimuth angle of surface normals from
the spectral variation of the phase of polarisation.
Moreover, to render the problem of simultaneous
estimation of surface orientation and index of
refraction well-posed, we enforce a generative model on
the material dispersion equations for the index of
refraction. This generative model, together with the
Fresnel transmission ratio, permit the recovery of the
index of refraction and the zenith angle simultaneously.
We show results on shape recovery and rendering for real
world and synthetic imagery.
View
Pdf
In addition, each light assumes the
power spectrum of either the natural sunlight or
an incandescent light. These
power spectra have been acquired from
sample light sources using a StellarNet
spectrometer.
StellarNet Releases New Solar Measurement System
Comparison of visible and infrared spectrum of light
sources-March
2011
M Rakic
and Goran Pichler – Institute of Physics, Croatia.
Optics Communications, 2011
We compared the visible and
the infrared spectrum of cesium and the sodium high
pressure discharge light sources of 70 W power, run at
different voltages from 180 to 240 V. Although the
cesium discharge lamp exhibits remarkable white light in
the visible spectrum, it suffers from the large infrared
radiation intensity. The study of the causes of large
infrared losses and their possible reduction was the
main motivation for the present investigation. Sodium
discharge plasma appears to be more efficient light
source than the cesium discharge plasma due to the
smaller infrared emission, although the latter has much
better colour rendering index. ... 5 mm.
For the infrared spectral
region the StellarNet RED-Wave
spectrometer (512 pixels, resolution 3.1 nm).
Photoelectrochemical Performance of Anatase TiO2
Thin Films Deposited by Self-Limiting Growth Techniques-
May 27, 2010
Fengli Wang,
Nicholas G. Kubala, and Colin A. Wolden
Department of Chemical
Engineering, Colorado School of Mines
Anatase TiO2 photoanodes were
deposited by self-limiting growth techniques at low
temperature. The optical bandgap and flatband
voltage of the as-deposited films agree with
the values obtained from single crystal anatase.
The donor density could be increased by both UV
illumination and cathodic polarization in
acidic solutions. Improvements in photocurrent scaled
closely with changes in carrier concentration,
with over 20-fold enhancements observed over
the as-deposited films. The threshold potential for
hydrogen intercalation was −0.6 V vs Ag/AgCl.
At this level the carrier concentration could
be manipulated with no change in optical
transmission. At lower potentials irreversible changes
are observed which are attributed to the
reduction of the underlying indium tin oxide
contact. In contrast, no changes were observed when
fluorinated tin oxide was used as the contact
layer.
...
All films were polycrystalline in nature, displaying the
anatase signatures in both X-ray diffraction
patterns and Fourier transform IR spectra.
Transmission measurements on deposited films
were performed using a UV/visible
spectrophotometer (Stellarnet). ...
View PDF...
Spectral analysis of femtosecond pulse diffraction
through binary diffractive optical elements: theory and
experiment
O
Mendoza-Yero, G Mínguez-Vega, J Lancis, E Tajahuerce,
and V Climent-OPTICS EXPRESS, Vol 16, No.4.
We report
on the changes in the spectrum of a femtosecond pulse
originated by diffraction of the ultrashort waveform
through a circularly symmetric binary diffractive
optical element. The analysis is performed in the
framework of the Rayleigh-Sommerfeld formulation of the
diffraction, where an analytical expression for the
monochromatic amplitude distribution close to the
optical axis is obtained. To corroborate our results, we
experimentally measure the variations of the pulse
spectrum within the collecting area of a spectrometer
located at the output plane. Multiple splitting of the
pulse spectrum in the vicinity of a focal position and a
phase singularity are shown... The output integrated
power spectrum was measured with a StellarNet EPP2000
fiber optics spectrometer (wavelength range from 135 nm
to 1100 nm), whose input collecting area was limited by
a pinhole…View
PDF.
Fig. Integrated output spectrum for pinholes of a) r0
=
75ìm
, b) r0
=
200ìm
and c) for the incoming ultrashort pulse (without
pinhole).
Electrical and gas sensing properties of
polyaniline-chloroaluminium phthalocyanine composite
thin films
M. E. Azim-Araghi and M. J.
Jafari-
Applied Physics Division, Physics Department,
Tarbiat Moallem University, Tehran, Iran
Electrical and gas sensing properties
polyaniline-chloroaluminium phthalocyanine (PAni-ClAlPc)
composite thin films were investigated to study the
gas sensing behavior of composites. Devices (chemiresistor
gas sensors) were prepared by spin coating method
from PAni as the base of composites and ClAlPc (with
different concentrations) as the second component
onto interdigitated electrodes. The sensitivity,
reversibility, response and recovery time of these
thin films on exposure to different concentrations
(0–2000 ppm) of CO2 gas
and the suitability of different composites as
materials to be used in practical gas sensors at
different temperatures were investigated. The
sensitivity factor of composites was obtained in a
range between 0.05–7.20. PAni + 10% ClAlPc was the
perfect candidate composite to fabricate gas sensor
at 300 K and PAni + 15% ClAlPc at 350 K. Thus, (PAni-ClAlPc)
composites have better response than pure PAni.
After that, devices were exposed to humidity, an
unexpected behavior was absorbed. Conductivity of
thin films were increased on exposure lower RH% and
decreased on higher RH%. Finally, 1000 ppm CO2 was
mixed to humidity and introduced to chamber,
obtained results showed the CO2 mixtures
decreased the sensitivity of thin films in compare
with pure CO2.
... This was spun at a
speed of 500 rpm for 5 s and at a speed of 2.500 rpm
for 15 s after coating,
devices were dried at room temperature for 24 h. The
thicknesses of thin films were measured
in the range 400–500 nm by optical
spectrometer (StellarNet.
TF-C-UVIS). ...
Comparison of diode-side-pumped Nd:YAG and Nd:YAP laser-
Jan Sulca, Helena Jelínková, Jan
K. Jabczy nski Waldemar Z_ endzianb, Jacek Kwiatkowskb,
Karel Nejezchleb, Václav skoda- Czech Technical
University, Faculty of Nuclear Sciences and Physical
Engineering- Military University of Technology,
Institute of Optoelectronics
Nd:YAG and Nd:YAP slab crystal in the form of
triangle with the Brewster-angle-cut polished input
faces was used as an active medium for diode-side-pumped
laser. A horizontal projection of the active medium form
is a triangle with 19.22mm long base, 5mm height, and
thickness of 4 mm. This active crystal shape is one from
the simplest form which makes possible to realise a slab
side-pumped con guration with a total internal re ection.
Optical pumping was accomplished by a quasi-cw diode
ARR18P400 with peak power 400W closely attached to the
active crystal without any coupling optics. Both
material were operated for most known Nd3+ ion
transition 4F3=2 ! 4I11=2 (1 ¹m) as well as for
transition 4F3=2 ! 4I13=2 which leads to the emission at
1.3 ¹m. The systems were tested in free running and Q
switch regime. This system is enough compact to be
useful tools for direct medical application.
View PDF...
Spectrum of free-running Nd:YAG laser
emission corresponding to operation at Nd3+
transition 4F3=2 ! 4I13=2
and Spectrum of free-running Nd:YAP laser emission
corresponding to operation at Nd3+ transition 4F3=2 !
4I13=2.
Spectroscopic
Diagnostics of an Atmospheric Microwave
Plasma for
Monitoring Metals Pollution
P. P. Woskov, K. Hadidi,
M. C. Borrás, P. Thomas, K. Green, G. J. Flores
Plasma Science and Fusion Center, Massachusetts
Institute of Technology
A 1.5 kW, 2.45 GHz microwave
sustained plasma in a flowing sample of stack exhaust
gas has been shown in recent DOE/EPA testing to
be an accurate monitor of trace
hazardous metals (in the part per billion range)
such as lead, chromium, and beryllium.
Optical-UV spectroscopic studies are being
carried out to better understand this particular
atmospheric pressure plasma torch.
OH Emission
Spectra of Hybrid Rocket Motors
Using PMMA and HTPB
Edmond W. Wilson,
Jr., James E. Mackey, Brett D.
Keller, Elaine J. Goertzen, Sheryl A. Clements,
and Charles D.
Rivenbark-
Harding University
and Calvin Cox- University of Arkansas
The development of
sensors for hybrid
rocket motors has lead to the
use of near-infrared
diode lasers
for characterizing hybrid rocket plumes.
Emission Spectra
obtained can be used to calculate species
concentrations and temperatures, both
spatially and temporally, in rocket
exhaust plumes. In this paper we
report our findings from a study of the
emission spectra of
hybrid rocket exhaust plumes in the ultraviolet,
UV, visible, VIS, and near-infrared, NIR,
regions of the
electromagnetic spectrum.
View PDF
StellarNet
BLACK-Comet Spectrometer series
are the new analogue of old
EPP2000C models
Ultraviolet-Visible Spectrometry
Characterization of Combustion in Hybrid Rocket Motors
Edmond W. Wilson, Jr.,
Brett D. Keller, Kellen M. Harkness,Christopher S.
Smeal, Megan S. Easterly and James E. Mackey,
Department of Physical Science, Harding
University
Small, portable ultraviolet and
visible spectrometers can be used to characterize the
combustion and regression
rates of hybrid rocket and other combustion emission
plumes. In this study, two spectrometers,
operating in the ultraviolet and visible ranges,
were used to measure the hydroxyl radical emission
spectrum and the broadband
visible emission spectrum of hybrid rocket motors under
a variety of oxidizer to fuel
ratios. Time and spatial profiles were measured along
with regression rates. Correlations were drawn
between broadband emission
spectra and regression rates.View
PDF
Organic semiconductor devices for micro-optical
applications
Martin Punke, Steffen
Mozer, Marc Stroisch, Martina
Gerken, Georg Bastian, Uli
Lemmer, Dominik G. Rabus, and Patric
Henzi
Universität Karlsruhe (TH), Light Technology Institute (LTI),
Institute for Microstructure Technology, Baskin School
of Engineering, University of California, Santa Cruz
The use of organic optoelectronic devices
such as organic light-emitting diodes and organic
photodiodes in micro-optical
systems is discussed. Potential applications like
optical interconnects and optical sensor systems are
examined. Device
characteristics including emission spectra, I-V-curves
and the dynamic behaviour are analyzed.
In the combination with a
polymeric optical fibre (POF) a transmission line
comprising a organic light emitting diode and
organic photodiodes is demonstrated. An important
step towards integration is realized by coupling the
amplified spontaneous emission
of an organic semiconductor material into a single
mode polymethylmethacrylate (PMMA)
waveguide.
View PDF
Colour-tunable spiral photonic actuators
Kwang-Un Jeong, Ji-Hyun
Jang, Cheong Yang Koh, Matthew J. Graham, Kwang-Yong
Jin, Soo-Jin Park, Changwoon Nah, Myong-Hoon Lee,
Stephen Z. D. Cheng and Edwin L. Thomas
Department of Polymer-Nano Science
and Technology, and Polymer Materials Fusion Research
Centre, Chonbuk National University, Korea
Combining the multi-faceted environmental
responsiveness of polymers with photonically
active structures, we developed spiral
photonic actuators which can reversibly
change both shape and colour in response to
the chemical environment.
Read more...
Experimental reflectivity spectra of the
fabricated photonic crystals: (a) silica, (b) PDMS/silica,
(c) PDMS/silica in hexane, and (d) PDMS/silica in acetic
acid.
Wavelength-scalable hollow optical
fibres with large photonic bandgaps
for CO2 laser transmission
Burak Temelkuran, Shandon
D. Hart, Gilles Benoit, John
D. Joannopoulos & Yoel Fink- Research
Laboratory of Electronics and Department of Materials
Science and Engineering, Massachusetts Institute of
Technology
Here we report on the design and
drawing of a hollow
optical fibre lined with an interior
omnidirectional dielectric
mirror.
Confinement of light in the hollow core is
provided by the large
photonic bandgaps
established by the multiple alter-nating
submicrometre-thick layers of a
high-refractive-index
glass and a low-refractive-index polymer. The
fundamental and
high-order transmission windows are determined
by the layer
dimensions and can be scaled from 0.75 to 10.6mm
in wavelength.The transmission losses are found
to be less than 1.0 dB
m 21,
orders of magnitude lower than those of
the intrinsic fibre
material, thus demonstrating that low
attenuation can be achieved
through structural design rather than
high-transparency
material selection.
Physical properties of CdS/ITO thin films growth
by CBD technique with substrate oscillating
agitation
Y.
A. Salazar; R. Patiño; J. L. Peña; W. Cauich; A.I. Oliva
Centro de Investigación y de Estudios Avanzados
del IPN Unidad Mérida, Departamento de Física Aplicada
Cadmium sulphide (CdS) thin films
deposited on indium tin oxide (ITO) substrates were
prepared by chemical bath deposition technique by using
different conditions to agitate the bath and the
substrate. The deposited films were characterized on
their morphology, on the band gap energy, and on
thickness. The implemented novel technique for substrate
oscillation has shown to improve the films quality, by
the chemical bath without colloidal precipitates and by
the clean film surfaces obtained. CdS films with
variable deposition time can be achieved depending on
the agitating technique.
In addition, by oscillating only the
substrate during deposition is possible to obtain clean
films and avoid the formation of colloidal precipitates
on the chemical bath, normally presented when it is
magnetically or ultrasonically agitated.
Read more...
High Power UV and
VUV Pulsed Excilamps
V. TARASENKO, M. EROFEEV,
M. LOMAEV, D. RYBKA Institute
of High Current Electronics
Academichesky
Emission characteristics of a
nanosecond discharge in inert gases and its
halo-genides without preionization of the gap
from an auxiliary source have been investigated.
A volume discharge, initiated by an
avalanche electron beam (VDIAEB) was realized at
pressures up to 12 atm. In xenon at
pressure of 1.2 atm, the energy of spontaneous
radiation in the full
solid angle was 45 mJ/cm
3 , and the FWHM of a radiation pulse was
110ns. The spontaneous radiation power
rise in xenon was observed at pressures up to 12
atm.
Read more...
Chemistry
Luminescence Properties and Quenching Mechanisms of Ln
(Tf2N) 3 Complexes in the Ionic Liquid bmpyr Tf2N-June
2011
A Brandner,
T Kitahara, N Beare, C Lin, MT Berry, and P. Stanley May
- Inorganic Chemistry, ACS publications.
The emission properties, including
luminescence lifetimes, of the lanthanide complexes
Ln(Tf2N)3 (Tf2N
= bis(trifluoromethanesulfonyl)amide); Ln3+ =
Eu3+, Tm3+, Dy3+, Sm3+,
Pr3+, Nd3+, Er3+) in
the ionic liquid bmpyr Tf2N (bmpyr = 1-n-butyl-1-methylpyrrolidinium)
are presented. The luminescence quantum efficiencies, η,
and radiative lifetimes, τR, are
determined for Eu3+(5D0),
Tm3+(1D2), Dy3+(4F9/2),
Sm3+(4G5/2), and Pr3+(3P0)
emission. The luminescence lifetimes in these systems
are remarkably long compared to values typically
reported for Ln3+ complexes
in solution, reflecting weak vibrational quenching. The
1.5 μm emission corresponding to the Er3+ (4I13/2→4I15/2)
transition, for example, exhibits a lifetime of 77 μs.
The multiphonon relaxation rate constants are determined
for 10 different Ln3+emitting states, and the
trend in multiphonon relaxation is analyzed in terms of
the energy gap law. The energy gap law does describe the
general trend in multiphonon relaxation, but deviations
from the trend are much larger than those normally
observed for crystal systems. The parameters determined
from the energy gap law analysis are consistent with
those reported for crystalline hosts. Because Ln3+ emission
is known to be particularly sensitive to quenching by
water in bmpyr Tf2N, the binding properties
of water to Eu3+ in
solutions of Eu(Tf2N)3 in
bmpyr Tf2N have been quantified. It is
observed that water introduced into these systems binds
quantitatively to Ln3+. It is demonstrated
that Eu(Tf2N)3 can
be used as a reasonable internal standard, both for
monitoring the dryness of the solutions and for
estimating the quantum efficiencies and radiative
lifetimes for visible-emitting [Ln(Tf2N)x]3–xcomplexes
in bmpyr Tf2N...
resolved photon counting. The detection system was
calibrated for relative wavelength response using a
standard Tungsten lamp with extended calibration out to
1700 nm. (Stellar Net, SL1-CAL). Luminescence lifetimes
visible.
View PDF.
%203%20Complexes%20in%20the%20Ionic%20Liquid%20bmpyr%20Tf2N.jpg)
Battery-operated, argon–hydrogen microplasma on hybrid,
postage stamp-sized plastic–quartz chips for elemental
analysis of liquid microsamples using a portable …-September
2011
S Weagant, V Chen, and V
Karanassios - Analytical and Bioanalytical Chemistry
A battery-operated, atmospheric pressure,
self-igniting, planar geometry Ar–H2 microplasma
for elemental analysis of liquid microsamples is
described. The inexpensive microplasma device (MPD)
fabricated for this work was a hybrid plastic–quartz
structure that was formed on chips with an area
(roughly) equal to that of a small-sized postage stamp (MPD
footprint, 12.5-mm width by 38-mm length). Plastic
substrates were chosen due to their low cost, for rapid
prototyping purposes, and for a speedy microplasma
device evaluation. To enhance portability, the
microplasma was operated from an 18-V rechargeable
battery. To facilitate portability even further, it was
demonstrated that the battery can be recharged by a
portable solar panel. The battery-supplied dc voltage
was converted to a high-voltage ac. The ∼750-μm
(diameter) and 12-mm (long) Ar–H2 (3%
H2)
microplasma was formed by applying the high-voltage ac
between two needle electrodes. Spectral interference
from the electrode materials or from the plastic
substrate was not observed. Operating conditions were
found to be key to igniting and sustaining a microplasma
that was simply “warm” to the touch (thus alleviating
the need for cooling or other thermal management) and
that had a stable background emission. A small-sized
(900 μL internal volume) electrothermal vaporization
system (40-W max power) was used for microsample
introduction. Microplasma background emission in the
spectral region between 200 and 850 nm obtained using a
portable fiber-optic spectrometer is reported and the
effect of the operating conditions is described. Analyte
emission from microliter volumes of dilute
single-element standard solutions of Cd, Cu, K, Li, Mg,
Mn, Na, Pb, and Zn is documented. The majority of
spectral lines observed for the elements tested were
from neutral atoms. The relative lack of emission from
ion lines simplified the spectra, thus facilitating the
use of a portable spectrometer. Despite the relative
spectral simplicity, some spectral interference effects
were noted when running a multi-element solution. An
example of how interference in the spectral domain can
be resolved in the time domain using selective thermal
vaporization is provided. Analytical utility and
performance characteristics are reported; for example, K
concentrations in diluted (∼30 times) bottled water were
determined to be 4.1 ± 1.0 μg/mL (4 μg/mL was the stated
concentration), precision was about 25%, and the
estimated detection limits were in the picogram range
(or in nanograms per milliliter in relative units).
... Analyte emission was monitored using a portable
fiber- optic spectrometer with an integrating,
2,048-pixel charge- coupled device (CCD) detector (Fig.
2). The portable spectrometer was an enhanced parallel
port system (EPP 2000C) commercially available from
StellarNet Inc.
View PDF.
 |
Figure Battery-operated,
atmospheric-pressure microplasma on a chip
Atmospheric Microplasma Jet:
Spectroscopic Database Development and Analytical
Results-September
2011
RVL
Wal, JH Fujiyama-Novak, CK Gaddam, D Das, A Hariharan, B
Ward - Applied Spectroscopy V65, Issue 9, 2011
This paper presents a developed
dielectric-barrier-discharge-based “sniffer“ that offers
unique characteristics not available from other
techniques. It is a portable, highly specific, and
sensitive detector that operates at atmospheric
pressure. It provides both molecular and elemental
information on organic and inorganic gases and
particulate aerosols. Measurements were made to
electrically characterize the plasma and calculate the
energy coupled into the plasma. We created a signature
database for diverse chemicals based on the atomic and
diatomic emission spectrum that serves to classify the
compound and ideally recognize it by composition with
the optical emission intensity corresponding to
concentration. For some operational regimes and species,
emission from OH (A2Σ+-X2Π),
CH (A2Δ-X2Π), and often C2 (d3Πg-a3Πu;
Swan band system) diatomic radicals is produced. Limits
of detection extend to parts per billion (ppb) levels
for some species such as decane, 2-decanol, and
nitrobenzene. Results are presented for differentiation
of classes of organic compounds such as alkanes,
aromatics, oxygenates, chlorinated, and
nitrogen-containing organic compounds. ... The light
emitted from the plasma jet was collected by an optical
fiber bundle (F1000-UV-VIS-SR) connected to a
collimating lens (74-UV UV/VIS) and guided to the
StellarNet Black Comet C-25 Spectrometer (grating:
holographic 590 grooves/mm; slit width: 25 lm.
View PDF.
Nano-Biomimetic
Materials for the Detection of Chemical Agents in Gases,
Aerosols, and Solutions- Oct
2010
AL Jenkins,
LC Buettner and Michael
W. Ellzy -US Army Edgewood Chemical and Biological
Center
Recent advances in molecularly imprinted polymers (MIPs) have created a
new class of synthetic materials that can mimic the
function and selectivity of the bioreceptors with
significantly improved stability and real-time sensing
capability.1,
2 As a
result; molecularly imprinted polymers can provide high
sensitivity and selectivity for molecular recognition
while maintaining excellent thermal and mechanical
stability. MIPs have been demonstrated to be extremely
selective for the agents and related pesticides in water
and organic matrices, with detection limits in the low
parts per trillion3,
4 however the application of these materials for
air/vapor detection has never been demonstrated. This
work combines the sensitivity and selectivity of
previously demonstrated MIP sensors with the capture
efficiency of denuder technology to create a sensor
platform capable of detecting phosphorus based chemical
agents, hydrolysis products and pesticides in all
weaponized forms. Spectra were also collected with a
StellarNet Blue Wave miniature fiber optic UV-vis
Spectrometer (StellarNet Inc, Tampa, FL). The
MIP-Denuder system combined the MIP setup (both the
large benchtop version and the miniature StellarNet
setup) with the denuder.
View PDF…
 
Luminol-Based Enhanced Chemiluminescence Assay for
Quantification of Peroxidase and Hydrogen Peroxide in
Aqueous Solutions: Effect of Reagent pH and Ionic
Strength-
Oct
2010
Alok Bhandari,
Wongee Kim, and Keith Hohn-
Iowa State University, Kansas State University
The effect of reagent
pH and ionic strength was evaluated on the
horseradish peroxidase (HRP)-luminol-p-iodophenol
enhanced
chemiluminescence assay. This assay was
optimized for HRP and H2O2
quantification during enzyme-mediated remediation of
groundwater
or wastewater contaminated with phenolic chemicals. The
maximum chemiluminescence intensity (ICLmax)
and total area under the chemiluminescence intensity
profiles were measured as a function of p-iodophenol
concentration, reagent solution pH, and
reagent ionic strength. ICLmax values
were optimum at pH 8.5 and increased linearly
with reagent ionic strength. Optimum
chemiluminescence enhancement was produced at a p-iodophenol
concentration of 0.3 mM under the reaction
conditions. ICLmax values were
linearly correlated with HRP and H2O2
concentrations within the ranges of 0.1–1
activity units/mL and 0.1–1 mM, respectively. Results
indicate that the HRP-luminol-p-iodohenol
enhanced chemiluminescence assay has a potential to be
used for quantification of HRP activity and H2O2
concentration in aqueous solutions
encountered in groundwater remediation or wastewater
treatment scenarios.
... Experiments
were first conducted for baseline reaction conditions
defined by pH 8.5, 0.5-mM
luminol, 0.1-mM -iodophenol, 2 AU/mL HRP, 5-mM , and
50-mM ionic strength.
Chemiluminescence was
measured using an EPP Miniature Fiber Optic Spectrometer
from StellarNet...Read
More
A microelectrochemical scanning flow cell
with downstream analytics-January
2011
SO Klemm,
JC Schauer, B Schuhmacher and Achim Walter Hassel -
Electrochimica Acta.
The combination of a capillary based
microelectrochemical flow cell system and downstream UV–vis
analytics allows obtaining synchronized electrochemical
and spectroscopic data in a fully automated mode. This
method combination can be generally applied to
microelectrochemical studies in which an electrochemical
species is released or consumed during the
electrochemical reaction. For the example of pure zinc
surfaces, the characterization of the integrated
spectroscopic system is presented with a Zn2+ detection
limit below 0.1 μmol l−1 using
Zincon as complexing agent. A parameter screening of the
effect of pH in the range of 6.6–9.0 in borate buffer
reveals a linear increase in zinc dissolution with
proton concentration but a distinct step in the open
circuit potential from the active state (around −700 mV
SHE, pH 6.6–7.1) to the passive state (around −300 mV
SHE, pH 7.4–9.0) indicating the formation of a closed
passive layer. This mechanism is strongly influenced by
sulfate anions which increase the dissolution rate of
the passive film and promote the active state as
monitored by the dissolution profile and OCP (open
circuit potential) values. Within the scope of this
parameter variation, the congruency between OCP
transients, potentiodynamic sweeps and time resolved
dissolution profiles is discussed...
2.4. UV–vis spectroscopy. A StellarNet EPP 2000
(StellarNet Inc., Tampa, USA) spectrometer using a 2048
pixel OMA (optical multichannel array) with 300 μm fiber
optics was equipped with a
SL-1 Tungsten Halogen lamp with a wavelength range from
350 to 2300 nm.
Kinetic and thermodynamic study of the reaction
catalyzed by glucose-6-phosphate dehydrogenase with
nicotinamide adenine dinucleotide-January
2011
JS Martín
del Campo and Rodrigo Patiño - Thermochimica Acta.
The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC
1.1.1.49) from Leuconostoc
mesenteroides has
a dual coenzyme specificity with oxidized nicotinamide
adenine dinucleotide (NADox) and oxidized
nicotinamide adenine dinucleotide phosphate as electron
acceptors. The G6PD coenzyme selection is determined by
the metabolic cellular prevailing conditions. In this
study a kinetic and thermodynamic analysis is presented
for the reaction catalyzed by G6PD from L.
mesenteroides with
NADox as
coenzyme in phosphate buffer. For this work, an in
situ spectrophotometric
technique was employed based on the detection of one
product of the reaction. Substrate and coenzyme
concentrations as well as temperature and pH effects
were evaluated. The apparent equilibrium constant, the
Michaelis constant, and the turnover number were
determined as a function of each experimental condition.
The standard transformed Gibbs energy of reaction was
determined from equilibrium constants at different
initial conditions. For the product 6-phospho-d-glucono-1,5-lactone,
a value of the standard Gibbs energy of formation is
proposed, ΔfG
= −1784 ± 5 kJ mol−1.
The evolution of the reaction was followed in real time,
monitoring the NAD red product formation with a maximum
of absorption at 340 nm of wavelength, through an
optical probe connected to a spectrophotometer
(BLUE-Wave, StellarNet) with 0.20 or 2.0 cm of cell
length.
Visible Attenuated Total Reflection (ATR): A New
Technique for High-Strength Pigment Analyses
–March
2011
KA Lee,
Rich Danny C. - Applied Spectroscopy, 2011
A
visible-attenuated total reflection (visible-ATR) device
was designed to provide a method for directly
determining the relative tint strength in high-strength
inks. This device showed good reproducibility and the
spectra could be correlated to known values of relative
tint strength in viscous, highly pigmented inks well
within the industry-acceptable error (±5% tint
strength). The results of the visible-ATR measurements
were compared to those from mid-infrared (mid-IR) and
near-infrared (NIR) spectroscopy and the capabilities of
those techniques for determining ink strength. Mid-IR
analysis was able to directly quantify relative tint
strengths, as well as correlating to known values, and
to qualify ink products by spectral matching. NIR
analysis was able to quantify the tint strength based on
the vehicle concentrations in the NIR region. The
visible region of the NIR spectrometer was not able to
be used for quantification. The vis-ATR and mid-IR
spectra showed changes over the time scale of minutes,
indicating self-stratification of the pigment and
varnish. ...
optics. The reflected light was collected and channeled
to a detector system, the BLUE-Wave
(StellarNet, Inc., Tampa, FL) diode array. ... naphtha.
Spectra Wiz software (StellarNet,
Inc., Tampa, FL) version 4.2 with SWUpdate 4.2b
was used.
A survey of phosphors novel for thermography-
Oct
2010
J
Brubach, T Kissel, M Frotscher, M Euler, B Albert-
Journal of Luminescence, 2010
With regard to phosphor thermometry, seven
luminescent ceramic materials were synthesised and
characterised, namely CaMoO4:Eu3+,
CaTiO3:Pr3+, LaPO4:Eu3+,
LaVO4:Eu3+, LiAl5O8:Fe3+,
TiMg2O4:Mn4+ and ZnGa2O4:Mn2+.
In this context, emission spectra and temperature
lifetime characteristics are presented. Thus, a survey
of phosphors novel for thermography is given in order to
encourage further studies and more detailed
characterisations of the respective materials.
The luminescence
spectra were monitored by a fiber-coupled
StellarNet BLACK-Comet spectrometer
within a spectral range between 200 nm and 850nm
(grating: 600 lines / mm, slit width: 50 m, max.
resolution ...
Experimentally and theoretically observed native pH
shifts in a nanochannel array
–January
2009
Danny Bottenus,
Youn-Jin Oh, Sang M. Han, and Cornelius F.
Ivory,-Department of Chemical Engineering, Washington
State University and Department of Chemical and Nuclear
Engineering, Center for High Technology Materials,
University of New Mexico.
Lab-on-a-chip (LOC) technology
provides a powerful platform for simultaneous
separation, purification, and identification of low
concentration multicomponent mixtures. As the
characteristic dimension of LOC devices decreases down
to the nanoscale, the possibility of containing an
entire lab on a single chip is becoming a reality. This
research examines one of the unique physical
characteristics of nanochannels, in which native pH
shifts occur. As a result of the electrical double layer
taking up a significant portion of a 100 nm wide
nanochannel, electroneutrality no longer exists in the
channel causing a radial pH gradient. This work
describes experimentally observed pH shifts as a
function of ionic strength using the fluorescent pH
indicator 5-(and-6)-carboxy SNARF®-1 and compares it to
a model developed using Comsol Multiphysics. At low
ionic strengths (~ 3 mM) the mean pH shift is
approximately 1 pH unit whereas at high ionic strengths
(~ 150 mM) the mean pH shift is reduced to 0.1 pH units.
An independent analysis using fluorescein pH indicator
is also presented supporting these findings.Two
independent non-linear simulations coupling the Nernst-Planck
equation describing transport in ionic solutions
subjected to an electric field and Poisson's equation to
describe the electric field as it relates to the charge
distribution are solved using a finite element solver.
In addition, the effects of chemical activities are
considered in the simulations. The first numerical
simulation is based on a surface ζ-potential which
significantly underestimates the experimental results
for most ionic strengths. A modified model assuming that
SNARF and fluorescein molecules are able to diffuse into
the hydrolyzed SiO2
phase, and in the case of the
SNARF molecule, able to bind to neutral regions of the
SiO2
phase agrees quantitatively
with experimental results. The filtered emission
spectrum was then detected with an EPP2000-CXRs UV-VIS
spectrophotometer (StellarNet Inc, Tampa Bay, FL, USA).
Spectra Wiz software (StellarNet Inc, Tampa Bay, FL,
USA) measured the ratio of emission intensity at 580 nm
and 640 nm, respectively.
View PDF…
Engineering Photocatalytic Cements: Understanding TiO2
Surface Chemistry to Control and Modulate Photocatalytic
Performances-
June 7, 2010
Andrea Folli,
Isabelle Pochard, André
Nonat, Ulla H. Jakobsen,
Ashley M. Shepherd,
Donald E. Macphee
The present
work addresses the aggregation/dispersion properties of
two commercial titanias for application as
photocatalysts in concrete technology. A microsized
m-TiO2 (average particle size 153.7 ±
48.1 nm) and a nanosized n-TiO2
(average particle size 18.4 ± 5.0 nm) have been tested
in different ionic media (Na+, K+,
Ca2+, Cl−, SO42−,
synthetic cement pore solution) at different pHs and in
real cement paste specimens. Results highlighted that
ion–ion correlations play a fundamental role in TiO2
particles aggregation in the cement environment. A
particle aggregation model derived from TiO2
surface chemistry is proposed here and used to justify
such aggregation phenomena in real cement paste.
Scanning electron microscopy–energy-dispersive X-ray
spectroscopic investigations on hardened cement
specimens completely confirmed the qualitative model
based on titania surface chemistry. Experimental results
also show how size and nature of TiO2
aggregates dramatically influence the overall
photocatalytic activity of cementitious materials
containing TiO2....
Light absorption measurements were undertaken to derive
the band- gap between valence
band and conductance band and have been carried out on
TiO2 powder using UV diffuse
reflectance spectroscopy (StellarNet BLUE-Wave
Spectrometer, Tampa, FL). ...
View PDF...
A
study on methane coupling to acetylene under the
microwave plasma
SHEN ChangSheng,
SUN YongZhi, SUN DeKun & YANG HongSheng-State Key
Laboratory of Millimeter Waves; School of Electronic
Science and Engineering, Southeast University, Nanjing-School
of Chemistry and Chemical Engineering, Nanjing
University
By optimizing the microwave
chemistry reactor made of the rectangular waveguide
resonator, the methane conversion (the
maximum 93.7%) , the C2 hydrocarbon yield (the maximum
91.0%) and the acetylene yield (the maximum 88.6%) were
all
greatly increased under the microwave plasma.
Furthermore, for the optimal reactor, the change of the
methane conversion and
the C2 hydrocarbon yield is little within the range of
the pressures in the experiments. The C2 hydrocarbon is
mainly made up
of acetylene, and the selectivity for acetylene is above
90%. Energy yield and space time yield of acetylene are
also high. Optical
emission spectroscopy (OES) was adopted for the
diagnosis of methane coupling to acetylene under
microwave plasma.
The excited species (CH, C2, H2, Hα) were detected in
the spectra range of 300–750 nm. Based on the products
and the excited
species, the reaction mechanism of methane coupling
under microwave plasma was investigated, using the
thermodynamics
and kinetics of the chemical reaction.
View
PDF
Optical emission spectrum of
methane microwave plasma at 2020 Pa; (b) optical
emission spectrum of methane microwave plasma at 10100
Pa.
Living
anionic polymerization of methyl methacrylate
controlled by metal-free phosphazene
catalyst as observed
by small-angle neutron scattering, gel
permeation chromatography and UV-visible
spectroscopy
Nobuyoshi
Miyamoto,Yoshihisa Inoue, Satoshi Koizumia and Takeji
Hashimotoa-
Advanced Science Research Center, Japan Atomic Energy
Agency
Phosphazene (PZN) catalyst, PZN catalyst
coexisting with a co-catalyst 1-hydroxycyclohexyl phenyl
ketone and polymethylmethacrylate (PMMA)
have been observed for the first time by
small-angle neutron scattering (SANS) and UV-visible
spectroscopy to elucidate the aggregation behavior of
the PZN molecules themselves and the state of living
chain ends in a living polymer solution.
Read more...
Nano@micro: General Method for Entrapment of
Nanocrystals in Sol−Gel-Derived Composite
Hydrophobic Silica Spheres
Taleb Mokari, Hanan
Sertchook,Assaf Aharoni,Yuval Ebenstein,David Avnir,and
Uri Banin-
Institute of Chemistry, The Farkas Center
for Light Induced Processes, and The Center for
Nanoscience and
Nanotechnology, The Hebrew University of
Jerusalem, Israel
A general method for
entrapment of hydrophobically coated nanocrystals in
micrometer and submicrometer composite silica spheres,
nano@micro, was developed. The method employs two
starting solutions hydrophobic
solvent containing the sol−gel precursor, a polymer, and
the nanocrystals, and an emulsifying hydrophilic phase
which catalyzes the sol−gel process. The use of a
hydrophobic polymer, polystyrene, serves to encapsulate
the nanocrystals inside the spheres while maintaining
many of their original properties. The obtained nano@micro
spheres were characterized structurally by transmission
electron microscopy and scanning electron microscopy,
chemically by energy dispersive X-ray spectroscopy, and
optically by ensemble and single-particle fluorescence
spectroscopy. It is possible to control the size of the
microspheres from the 100 nm scale to the micrometer
scale, with good monodispersivity and with good
separation between the microspheres. The method is
demonstrated for encapsulating a wide variety of
nanocrystals, primarily semiconductors covering
different spectral bands, and of different shapes
including spheres and rods. The semiconductor
nanocrystals impart widely tunable emission to the
microspheres. A similar encapsulation technique was also
applied to thiol-coated Au particles. The technique is
generally applicable to other hydrophobic nanocrystal
systems of magnetic, oxide, and other materials.
Read more...
Fluorescence spectra were recorded using a
spectrometer/CCD setup (StellarNet
BLACK-Comet model).
Go to StellarNet
Fluorimetry page.
Multiple-Color
Electrochromism from Layer-by-Layer-Assembled
Polyaniline/Prussian Blue
Nanocomposite Thin
Films
Dean M. DeLongchamp
and Paula T. Hammond-
Department of Chemical Engineering,
Massachusetts Institute of Technology
The creation of new materials
systems for lightweight and flexible displays is an
extremely active research field. Electrochromic
displays possess a keen advantage over other
technologies because it is possible for a single
electrochromic pixel to produce multiple colors in
addition to white, depending on applied potential.
This possibility has proven quite challenging to
achieve in practice. Here we present the successful
fabrication of a multiply colored electrochromic
electrode using layer-by-layer (LBL) assembly. The
electrode films are created by exploiting intrinsic
electrostatic attraction between the polycation
poly(aniline) (PANI) and a negatively ionized
Prussian Blue (PB) nanoparticle dispersion. The
resultant organic/inorganic nanocomposites exhibit
excellent smoothness and a classical linear increase
in film thickness with assembly exposure steps.
Electrochemical and spectrophotometric
characterization confirms the distinct and
noninteracting contributions from PANI and PB and
reveals that both are fully electrochemically
accessible even in thick, high contrast films.
Switching speed is accelerated due to the
incorporation of electronically conducting PANI. The
PANI/PB nanocomposite undergoes an uncolored to
green to blue transition over the potential range
from −0.2 to 0.6 V vs K-SCE. These results validate
an LBL-assembly-based intermixing strategy for the
design of multiple-hue electrochromic electrode
films. Future horizons include extension to other
materials, with the eventual goal of creating a
single electrode film or electrochemical cell
capable of displaying any visible color on demand
Spectral characterization was performed with
a StellarNet
BLACK-Comet
concave grating UV−vis−NIR spectrophotometer
with combined incandescent and deuterium lamp
sources....Read
more...
Chemical Synthesis
of a Polyaniline/Gold Composite Using
Tetrachloroaurate
John M.
Kinyanjui and David W. Hatchett-
Department of Chemistry, University of Nevada
and J. Anthony Smith and Mira Josowicz-
Department of Chemistry and Biochemistry,
Georgia Institute of Technology
The chemical
synthesis of polyaniline (PANI)
is explored using
tetrachloroaurate,
AuCl4-.
These studies
provide a simple
method for the
oxidation of aniline
by AuCl4-
and simultaneous
formation of bulk
quantities of a PANI/Au
composite. In situ
UV/vis spectroscopy
indicates that the
rate of formation of
gold colloids and
intermediate
(short-chain) PANI
species is rapid in
comparison to that
of the long-chain
PANI. Longer PANI
chains are produced
at a slower rate, at
the expense of
short-chain
intermediate
species. The gold
particles act as
nucleation sites for
the oxidative
formation of PANI,
encapsulating the
metal in the form of
a polymer/metal
composite. Results
from the elemental
analysis and the
FTIR spectra of the
composite material
are consistent with
PANI produced using
only ammonium
persulfate as the
oxidant. In
addition, XPS,
optical microscopy,
and TEM diffraction
show that the gold
particles are
polycrystalline with
relatively constant
diameter (0.8−1 μm).
Finally, the PANI/Au/HBF4
conductance does not
change significantly
with the
introduction of Au
particles, relative
to that of PANI/HBF4
without Au
particles. These
studies provide a
new method for
growth of PANI/metal
composites where the
presence of the
metal in the polymer
does not adversely
affect the
electronic
structure.
All spectra were obtained using a
StellarNet
BLUE-Wave fiber
optic spectrophotometer equipped with a D2
lamp (SL3
Lamp) and tungsten filament
(SL1
Lamp) source that were
coupled into a single fiber. ...
Titania−Acrylic Coil Reactor for Photocatalytic
Water Purification and Sterilization
Luke H.
Loetscher, Jonathan M. Carey, Stephanie L. Skiles,
Vanessa M. Carey and Joel E. Boyd-
Department of Chemistry, Wayland Baptist
University
A titania−acrylic
composite reactor
was constructed with
a coil geometry. The
presence of multiple
titania layers
within the reactor
increases the
titania surface area
while making maximum
use of the
illumination
provided. Both
compact fluorescent
blacklight (CFL) and
ultraviolet light
emitting diodes
(LEDs) were used as
illumination
sources. An external
pump was used to
recirculate 650−800
mL of water
containing organic,
metallic, or
bacterial
contamination
through the coil
reactor. Complete
purification of the
water was achieved
within 300 min with
10 ppm methylene
blue, 10 ppm methyl
orange, 20 ppm Pb2+,
and 2200 colony
forming units per
milliliter (CFU/mL)
of E. coli
respectively using
the CFL source. The
effectiveness, low
cost, durability,
ruggedness, and
energy efficiency of
this reactor are
advantageous for
both portable and
fixed-base
applications.
Read more...
Spectra from both light sources and UV−vis
spectra for MB and MO were collected on a StellarNet
BLACK-Comet ... Irradiance
spectra were collected with a fiber-mounted
cosine receptor (StellarNet
model
CR2). ...
Electron Exchange
between α-Keggin Tungstoaluminates and a
Well-Defined Cluster-Anion Probe for Studies in
Electron Transfer
Yurii V. Geletii,
Craig L. Hill, Alan
J. Bailey, Kenneth I.
Hardcastle, Rajai H.
Atalla, and Ira A.
Weinstock
Fully oxidized α-AlIIIW12O405-
(1ox),
and
one-electron-reduced
α-AlIIIW12O406-
(1red),
are well-behaved
(stable and free of
ion pairing) over a
wide range of pH and
ionic-strength
values at room
temperature in
water. Having
established this,
27Al NMR
spectroscopy is used
to measure rates of
electron exchange
between 1ox
(27Al NMR:
72.2 ppm relative to
Al(H2O)63+;
ν1/2 =
0.77 Hz) and 1red
(74.1 ppm; ν1/2
= 0.76 Hz).
Bimolecular rate
constants, k,
are obtained from
line broadening in
27Al NMR
signals as ionic
strength, μ, is
increased by
addition of NaCl at
the slow-exchange
limit of the NMR
time scale. The
dependence of k
on μ is plotted
using the extended
Debye−Hückel
equation:
log k = log
k0
+ 2αz1z2μ1/2/(1
+ βrμ1/2),
where z1
and z2
are the charges of
1ox
and 1red,
α and β are
constants, and r,
the distance of
closest contact, is
fixed at 1.12 nm,
the crystallographic
diameter of a Keggin
anion. Although not
derived for highly
charged ions, this
equation gives a
straight line (R2
= 0.996), whose
slope gives a charge
product, z1z2,
of 29 ± 2,
statistically
identical to the
theoretical value of
30. Extrapolation to
μ = 0 gives a rate
constant k11
of (6.5 ± 1.5) × 10-3
M-1 s-1,
more than 7 orders
of magnitude smaller
than the rate
constant [(1.1 ±
0.2) × 105
M-1 s-1]
determined by
31P NMR for
self-exchange
between PVW12O403-
and its
one-electron-reduced
form, PVW12O404-.
Sutin's
semiclassical model
reveals that this
dramatic difference
arises from the
large negative
charges of 1ox
and 1red.
These results,
including
independent
verification of k11,
recommend 1red
as a well-behaved
electron donor for
investigating
outer-sphere
electron transfer to
molecules or
nanostructures in
water, while
addressing a larger
issue, the
prediction of
collision rates
between uniformly
charged nanospheres,
for which 1ox
and 1red
provide a working
model.
Instrumentation. UV−vis
spectra were acquired using
StellarNet Inc. EPP2000
spectrophotometers equipped with diode-array
detectors and immersible fiber-optic probes. ...
StellarNet Dip Probes
Evaluation of Photon Absorption in an Aqueous
TiO2 Slurry Reactor Using Monte Carlo
Simulations and Macroscopic Balance
Jesus Moreira, Benito
Serran, Aaron Ortiz and Hugo de Lasa-
Faculty of Engineering Science, Chemical
Reactor Engineering Centre, The University of
Western Ontario
The radiation field
in an annular photocatalytic
reactor is simulated
using a Monte Carlo
method (MC) for two
TiO2
suspensions in
water. Simulations
are performed by
using both the
spectral
distribution and the
wavelength-averaged
scattering and
absorption
coefficients. The
Henyey−Greenstein
phase function is
adopted to represent
forward, isotropic,
and backward
scattering modes. It
is assumed that the
UV lamp reflects the
backscattered
photons by the
slurred medium.
Photoabsorption
rates using MC
simulations and
spectral
distribution of the
optical coefficients
agree closely with
experimental
observations from a
macroscopic balance.
It is found that the
scattering mode of
the probability
density function is
not a critical
factor for a
consistent
representation of
the radiation field.
MC simulation for
the optimal catalyst
concentration
reveals that the
maximum LVREA is
reached at a
concentration of
0.14 g L−1
for TiO2
Degussa P25. From
this concentration,
the apparent optical
thickness is
determined to be
2.8476 which is in
agreement with the
optimal one
previously reported.
This concentration
is comparable to
that determined
experimentally for
phenol
photocatalytic
degradation.Read
more...
Soluble Narrow Band Gap and Blue
Propylenedioxythiophene- Cyanovinylene Polymers as
Multifunctional Materials for Photovoltaic and
Electrochromic Applications
(Dry-Box Studies using spectrometer)
Barry C. Thompson,Young-Gi Kim, Tracy D.
McCarley,and John R. Reynolds The George and
Josephine Butler Polymer Research Laboratory and the
Center for Macromolecular Science and Engineering,
Department of Chemistry, University of Florida
View PDF...
Removing Organic
Compounds from Aqueous Medium via Wet
Peroxidation by Gold Catalyst
Yi-Fan Han, Nopphawan
Phonthammachai, Kanaparthi Ramesh, Ziyi Zhong
and Tim White,
Institute of Chemical and Engineering Sciences,
1, Pesek Road, Jurong Island, Singapore
A new heterogeneous
Fenton-like system,
consisting of
supported Au
catalysts and
hydrogen peroxide,
was proved to be
effective in
removing low level
organic compounds
(ca. 100 ppm) such
as phenol, ethanol,
formaldehyde, and
acetone in aqueous
solution. Among all
gold catalysts the
Au/hydroxyapatite
(Au/HAp) exhibits
the highest
activity, and even
better than the
conventional iron
ions exchanged
zeolite (Fe/ZSM-5)
catalyst. In
particular, unlike
the limited
operational pH range
(pH: 2 5)
for the other
heterogeneous Fenton
catalysts such as
Fe/ZSM-5, Au/HAp
shows higher
stability even in
strong acid solution
(pH
2), due to almost no
leaching of active
metal from supports
into solution. It
can be potentially
applied in treating
the industrial
wastewaters with
strong acidity and
purifying drinking
water. In addition,
in the case of
complete oxidation
of phenol, a
plausible route was
suggested for deep
understanding of
this process.
StellarNet Color Analysis System-
The variation of H2O2
concentration during reaction was analyzed
colorimetrically using a UV–vis spectrophotometer
(Epp2000, StellarNet Inc.) after complexation with a
TiOSO4/H2SO4
reagent (16). ...Pictured
above
BLACK-Comet-CXR color
spectrophotometer,
SL1
Halogen Krypton Light Source, R400-7-VIS
Reflectance Probe, RPH1 Reflectance Probe Holder, and RS50 Reflection
Standard
Bio-Science
Effects of trehalose and sorbitol on the activity and
structure of Pseudomonas cepacia lipase: spectroscopic
insight-July
2011
A Azizi, B
Ranjbar, K Khajeh, T Ghodselahi, S Hoornam, H Mobasheri
- International Journal of Biological
Macromolecules, 2011
The
stability of enzymes with no reduction in their
catalytic activity still remains a critical issue in
industrial applications. Naturally occurring osmolytes
are commonly used as protein stabilizers. In this study
we have investigated the effects of sorbitol and
trehalose on the structural stability and activity of Pseudomonas
cepacia lipase
(PCL), using UV–visible, circular dichroism (CD) and
fluorescence spectroscopy. Surface plasmon resonance (SPR)
technique was used to trace changes in the refractive
index and dielectric constant of the environment. The
results revealed that catalytic activity and intrinsic
fluorescence intensity of PCL increased in the presence
of both osmolytes. Far-UV CD spectra indicated that the
protein has undergone some conformational changes upon
interacting with these osmolytes. Increasing the
concentration of sorbitol led to changes in the
refractive index and consequently the dielectric
constant of environment; whereas in the case of
trehalose, such changes were not significant.
Unfavorable interactions of trehalose with protein
surface induced higher preferential exclusion from the
enzyme–water interface than that of sorbitol. Results of
this report could give further insights about the
stabilization mechanism of osmolytes...
Then SPR absorption spectra of UV- Visible spectrometer,
Stellar.net (Florida, USA) from 2 mm diameter optical
fiber that transfers a non-polarized light beam (400 nm
-850 nm) through samples to a CCD detector was measured.
View PDF.
BBX32, An Arabidopsis B-box Protein,
Functions in Light Signaling by Suppressing
HY5-Regulated Gene Expression And Interacting with STH2
–June
2011
HE Holtan, S Bandong, CM Marion, L Adam, et al. Plant
Physiology, 2011.
A B-box
zinc finger protein, B-BOX32 (BBX32), was identified as
playing a role in determining hypocotyl length during a
large-scale functional genomics study. Further analysis
revealed that seedlings overexpressing BBX32 display
elongated hypocotyls in red, far-red and blue light,
along with reduced cotyledon expansion in red light.
Through comparative analysis of mutant and
overexpression line phenotypes, including global
expression profiling and growth curve studies, we
demonstrate that BBX32 acts antagonistically to HY5. We
further show that BBX32 interacts with STH2, another
Bbox protein previously shown to interact with HY5.
Based on these data, we propose that BBX32 functions
downstream of multiple photoreceptors as a modulator of
light responses. As such, BBX32 potentially has a native
role in mediating gene repression to maintain dark
adaptation... AR75L chamber (Percival) was used for
white light. Fluence rates were measured using a
spectroradiometer (EPP2000-VIS-50, StellarNet Inc).
Hypocotyl and cotyledon area measurements were performed
using digital images (Canon G9) analyzed with Image J.
View PDF.
Fig. 1.
Simplified model depicting a functional role of BBX32 in
photomorphogenesis. The hypothetical model indicates
that BBX32 interacts with STH2 and suppresses the
activities of positive factors, STH2 and HY5, involved
in photomorphogenesis that control multiple aspects of
seedling de-etiolation, including light-regulated gene
expression and cell expansion.
Dimerization and blue light regulation of PIF1
interacting bHLH proteins in Arabidopsis
-September
2011
Q Bu, A Castillon,
F Chen, L Zhu, et al. –Plant Molecular Biology
Phytochrome Interacting Factor 1
(PIF1), a basic helix-loop-helix (bHLH) protein,
functions as a negative regulator of various
facets of photomorphogenesis. To indentify
PIF1-interacting proteins, we performed yeast
two-hybrid screening using PIF1 as a bait and
identified a group of proteins including PIF1
itself, PIF3 and long hypocotyl
in far-red
1 (HFR1), an atypical HLH protein. Directed
yeast two-hybrid interaction assays showed that
PIF1 can form heterodimers with all other PIFs
as well as with HFR1. PIF1 and PIF3 interacted
with each other in both in vitro and in vivo co-immunoprecipitation
assays. PIF1-PIF3 heterodimer also bound to a
G-box DNA sequence element in vitro. To
understand the biological significance of these
interactions, a pif1pif3 double
mutant was obtained and characterized. Analyses
of the single and double mutants showed that
PIF3 plays a prominent role in repressing
photomorphogenesis under continuous blue light
conditions. pif1 and pif3 showed
additive phenotypes more prominently under
discontinuous blue light conditions. Similar to
PIF1, PIF3 was also rapidly phosphorylated,
poly-ubiquitylated and degraded in response to
blue light. PIF3 also interacted with
phytochromes in response to blue light. A PIF3
mutant defective in interaction with both phyA
and phyB displayed reduced degradation under
blue light, suggesting that phy-interaction was
necessary for the blue light-induced degradation
of PIF3. Taken together, these data suggest a
combinatorial control of photomorphogenesis by
bHLH proteins in response to light in
Arabidopsis.
... 2009; Shen et al. 2005). Light fluence rates
were measured using a spectroradiometer (Model
EPP2000, StellarNet Inc., Tampa, FL) as
described (Cast- illon et al. 2009; Shen et al.
2005). Adult plants were Plant Mol Biol 123 Page
3.
View PDF.
Collective Character of Previtamin D cis-trans
Isomerization in Liquid-Crystalline Matrices-June
2011
Irina Terenetskaya
& Tetiana Orlova - Molecular Crystals and Liquid
Crystals, Vol. 541, Iss. 1, 2011
Significant increase of the previtamin D cis-trans isomerization
efficiency with increased concentration of initial
provitamin D was observed in both nematic and
cholesteric LCs at room temperature, but the effect
revealed reduced progressively with heating, and in
isotropic phase it disappeared. The results obtained
indicate on the collective character of cis-trans isomerization
in liquid crystals due to the ordering of LCs. Here we
present our results on the dynamics of the cholesteric
phase induction and its propagation in response to the
UV-induced geometry change of the provitamin D dopant
molecule...
The power of the incident radiation was measured with
the calibrated spectrometer EPP2000C-UV+VIS (StellarNet
Inc.), and in the sample plane it amounted to 0.3 mW/cm
2…
View PDF.
Skin Lesions Classification with Optical Spectroscopy
- September 2010
A. Safi, V.
Castaneda, T. Lasser, N. Navab-
Technische Universität München, Germany
Diagnosis of benign and malign
skin lesions is currently mostly relying on visual
assessment and frequent biopsies performed by
dermatologists. As the timely and correct diagnosis of
these skin lesions is one of the most important factors
in the therapeutic outcome, leveraging new technologies
to assist the dermatologist seems natural. Complicating
matters is a blood cancer called Cutaneous T-Cell
Lymphoma, which also exhibits symptoms as skin lesions.
We propose a framework using optical spectroscopy and a
multi-spectral classification scheme using support
vector machines to assist dermatologists in diagnosis of
normal, benign and malign skin lesions. As a first step
we show successful classification (94.9%) of skin
lesions from regular skin in 48 patients based on 436
measurements. This forms the basis for future automated
classification of different skin lesions in diseased
patients.
View PDF...
(a) Schematic of the fiber arrangement in
the spectroscopy probe: 6×200μm illumination fibers
arrayed around one 600μm acquisition fiber. (b) System
setup: (1) tracking cameras, (2) regular camera (for
augmented reality visualization), (3) tracked probe, (4)
spectrometer, (5) light source, and (6) data–processing
unit. The right Graph of all normalized spectra from the
training data set T, color-coded as blue for skin moles,
red mole cancer and green for normal skin.
The emerging roles of melanopsin in behavioral
adaptation to light-
August 30, 2010
Megumi Hatori and
Satchidananda Panda-
The Salk Institute for Biological Studies
The adaptation of behavior and physiology to changes in
the ambient light level is of crucial importance to
life. These adaptations include the light modulation of
neuroendocrine function and temporal alignment of
physiology and behavior to the day:night cycle by the
circadian clock. These non-image-forming (NIF) responses
can function independent of rod and cone photoreceptors
but depend on ocular light reception, suggesting the
participation of novel photoreceptors in the eye. The
discovery of melanopsin in intrinsically photosensitive
retinal ganglion cells (ipRGCs) and genetic proof for
its important role in major NIF responses have offered
an exciting entry point to comprehend how mammals adapt
to the light environment. Here, we review the recent
advances in our understanding of the emerging roles of
melanopsin and ipRGCs. These findings now offer new
avenues to understand the role of ambient light in
sleep, alertness, dependent physiologies and potential
pharmacological intervention as well as lifestyle
modifications to improve the quality of life....
The emission spectra for popular fluorescent lamps
(black line) used for indoor lighting and
sunlight (gray line; two hours after sunrise in
San Diego, April 2010) were
measured and analyzed using a
BLUE-Wave UV–VIS spectrometer and SpectraWiz software (StellarNet
Inc.). ...
Read more...
Microbial UV Fluence-Response Assessment using a Novel
UV-LED Collimated Beam System
- December 2010
C Bowker, J Ducoste, A
Sain, and Max Shatalov Hazen
and Sawyer, Department of Civil, Construction, and
Environmental Engineering, North Carolina State
University, Sensor Electronic Technology, Inc. SC.
A research study has been
performed to determine the ultraviolet (UV) fluence-response
of several target non-pathogenic microorganisms to UV
light emitting diodes (UV-LEDs) by performing collimated
beam tests. UV-LEDs do not contain toxic mercury, offer
design flexibility due to their small size, and have a
longer operational life than mercury lamps. Comsol
Multiphysics was utilized to create an optimal UV-LED
collimated beam design based on number and spacing of
UV-LEDs and distance of the sample from the light source
while minimizing the overall cost. The optimized UV-LED
collimated beam apparatus and a low-pressure mercury
lamp collimated beam apparatus were used to determine
the UV fluence-response of three surrogate
microorganisms (E. coli, MS-2, T7)
to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm
low-pressure mercury lamps. Irradiation by low-pressure
mercury lamps produced greater E.
coli and
MS-2 inactivation than 255 nm and 275 nm UV-LEDs and
similar T7 inactivation to irradiation by 275 nm
UV-LEDs. The 275 nm UV-LEDs produced more efficient T7
and E.
coli inactivation
than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs
produced comparable microbial inactivation for MS-2.
Differences may have been caused by a departure from the
time-dose reciprocity law due to microbial repair
mechanisms.
... 167 The incident irradiance at the surface of the
liquid sample was found for the UV-168 LED
experiments using a Stellarnet
BLACK-Comet-100 Spectroradiometer with an
attached 169 fiber optic probe
to capture fine planar variations in light
intensity calibrated at both 255 170
Kinetic and thermodynamic study of the
reaction catalyzed by glucose-6-phosphate dehydrogenase
with nicotinamide adenine dinucleotide-January
2011
JS Martín
del Campo and Rodrigo Patiño - Thermochimica Acta.
The enzyme glucose-6-phosphate dehydrogenase (G6PD, EC
1.1.1.49) from Leuconostoc
mesenteroides has
a dual coenzyme specificity with oxidized nicotinamide
adenine dinucleotide (NADox) and oxidized
nicotinamide adenine dinucleotide phosphate as electron
acceptors. The G6PD coenzyme selection is determined by
the metabolic cellular prevailing conditions. In this
study a kinetic and thermodynamic analysis is presented
for the reaction catalyzed by G6PD from L.
mesenteroides with
NADox as
coenzyme in phosphate buffer. For this work, an in
situ spectrophotometric
technique was employed based on the detection of one
product of the reaction. Substrate and coenzyme
concentrations as well as temperature and pH effects
were evaluated. The apparent equilibrium constant, the
Michaelis constant, and the turnover number were
determined as a function of each experimental condition.
The standard transformed Gibbs energy of reaction was
determined from equilibrium constants at different
initial conditions. For the product 6-phospho-d-glucono-1,5-lactone,
a value of the standard Gibbs energy of formation is
proposed, ΔfG
= −1784 ± 5 kJ mol−1.
The evolution of the reaction was followed in real time,
monitoring the NAD red product formation with a maximum
of absorption at 340 nm of wavelength, through an
optical probe connected to a spectrophotometer
(BLUE-Wave, StellarNet) with 0.20 or 2.0 cm of cell
length.
Phosphorylation by CK2 enhances the rapid light-induced
degradation of PHYTOCHROME INTERACTING FACTOR 1 in
Arabidopsis
–February 2011
Q Bu, L
Zhu, MD Dennis, L Yu, SX Lu… - Journal of Biological,
2011
The phytochrome family of sensory photoreceptors
interacts with Phytochrome Interacting Factors (PIFs),
repressors of photomorphogenesis, in response to
environmental light signals and induces rapid
phosphorylation and degradation of PIFs to promote
photomorphogenesis. However, the kinase that
phosphorylates PIFs is still unknown. Here we show that
CK2 directly phosphorylates PIF1 at multiple sites. α1
and α2 subunits individually phosphorylated PIF1 weakly
in vitro. However, each of four β subunits
strongly stimulated phosphorylation of PIF1 by α1 or α2.
Mapping of the phosphorylation sites identified 7 Ser/Thr
residues scattered throughout PIF1. Ser/Thr to Ala
scanning mutations at all 7 sites eliminated
CK2-mediated phosphorylation of PIF1 in vitro.
Moreover, the rate of degradation of the Ser/Thr to Ala
mutant PIF1 was significantly reduced compared to wild
type PIF1 in transgenic plants. In addition, hypocotyls
lengths of the mutant PIF1 transgenic plants were much
longer than the wild type PIF1 transgenic plants under
light, suggesting that the mutant PIF1 is suppressing
photomorphogenesis. Taken together, these data suggest
that CK2-mediated phosphorylation enhances the
light-induced degradation of PIF1 to promote
photomorphogenesis. Plant Growth Conditions and
Phenotypic Analyses- Plants were grown in Metro-Mix 200
soil (Sun Gro Horticulture, Bellevue, WA) under constant
light at 24 °C ± 0.5°C. Monochromatic R
and FR light sources and the spectroradiometer
(Model BLUE-Wave, StellarNet Inc., Tampa ).
View PDF.
Supplementary Figure: LUC-PIF1(S464-466A) mutant
promotes hypocotyl elongation under red
light. Photographs showing hypocotyl lengths of various
genotypes including two
independent alleles of LUC-PIF1(S464-466A) transgenic
plants. Seedlings were grown for four
days in the dark or one day in the dark followed
by three days under red light (7
ìmolm-2s-1).
Bar= 5 mm.
Deactivation of A549 cancer cells in vitro by a
dielectric barrier discharge plasma needle-March
2011
J Huang, W
Chen, H Li, XQ Wang, GH Lv… - Journal of Applied
Physics, 2011
An
inactivation mechanism study on A549 cancer cells by
means of a dielectric barrier discharge plasma needle is
presented. The neutral red uptake assay provides a
quantitative estimation of cell viability after plasma
treatment. Experimental results show that the efficiency
of argon plasma for the inactivation process is very
dependent on power and treatment time. A 27 W power and
120 s treatment time along with 900 standard cubic
centimeter per minute Ar flow and a nozzle-to-sample
separation of 3 mm are the best parameters of the
process. According to the argon emission spectra of the
plasma jet and the optical microscope images of the A549
cells after plasma treatment, it is concluded that the
reactive species (for example, OH and O) in the argon
plasma play a major role in the cell deactivation.
... They were quite useful for diagnostic purposes.
Figure is a typical UV-visible emission spectrum (Stellarnet,
BLACK-Comet in the 200–850 nm
regions from sine wave ac driven (11.55 kHz) DBD plasma
at atmospheric pressure.
A novel high-throughput in vivo molecular screen for
shade avoidance mutants identifies a novel phyA mutation
-March
2011
X Wang, I Roig-Villanova,
S Khan, H Shanahan… - Journal of Experimental Botany …,
2011
The shade avoidance
syndrome (SAS) allows plants to anticipate and avoid
shading by neighbouring plants by initiating an
elongation growth response. The phytochrome
photoreceptors are able to detect a reduction in the
red: far red ratio in incident light, the result of
selective absorption of red and blue wavelengths by
proximal vegetation. A shade-responsive luciferase
reporter line (PHYB::LUC) was used to carry out a
high-throughput screen to identify novel SAS mutants.
The dracula 1 (dra1) mutant, that showed no avoidance of
shade for the PHYB::LUC response, was the result of a
mutation in the PHYA gene. Like previously characterized
phyA mutants, dra1 showed a long hypocotyls in far red
light and an enhanced hypocotyl elongation response to
shade. However, dra1 additionally showed a long
hypocotyl in red light. Since phyB levels are relatively
unaffected in dra1, this gain-of-function red light
phenotype strongly suggests a disruption of phyB
signalling. The dra1 mutation, G773E within the phyA
PAS2 domain, occurs at a residue absolutely conserved
among phyA sequences. The equivalent residue in phyB is
absolutely conserved as a threonine. PAS domains are
structurally conserved domains involved in molecular
interaction. Structural modelling of the dra1 mutation
within the phyA PAS2 domain shows some similarity with
the structure of the phyB PAS2 domain, suggesting that
the interference with phyB signalling may be the result
of non-functional mimicry. Hence, it was hypothesized
that this PAS2 residue forms a key distinction between
the phyA and phyB phytochrome species.... All light
measurements were made using a StellarNet EPP2000-HR
spectroradiometer. Luciferase imaging. Following 6 d
growth in constant white light, seedlings were sprayed
with 1 mM d-luciferin dissolved in 0.01% Triton
(1 ml per plate).
Tar analysis from biomass gasification by means of
online fluorescence spectroscopy-
March 2011
C Baumhakla and Sotirios
Karellasb - Optics and Lasers in Engineering, 2011
Optical
methods in gas analysis are very valuable mainly due to
their non-intrusive character. That gives the
possibility to use them for in-situ or online
measurements with only optical intervention in the
measurement volume. In processes like the gasification
of biomass, it is of high importance to monitor the gas
quality in order to use the product gas in proper
machines for energy production following the
restrictions in the gas composition but also improving
its quality, which leads to high efficient systems. One
of the main problems in the biomass gasification process
is the formation of tars. These higher hydrocarbons can
lead to problems in the operation of the energy system.
Up to date, the state of the art method used widely for
the determination of tars is a standardized offline
measurement system, the so-called “Tar Protocol”. The
aim of this work is to describe an innovative, online,
optical method for determining the tar content of the
product gas by means of fluorescence spectroscopy. This
method uses optical sources and detectors that can be
found in the market at low cost and therefore it is very
attractive, especially for industrial applications where
cost efficiency followed by medium to high precision are
of high importance…
On the opposite window a laser beam dump was mounted. To
detect the fluorescence signal a compact UV/vis
concave grating spectrometer
"BLACK-Comet" of the company
StellarNet Inc. [23] is used.
Identification and Discrimination of Bacterial Strains
by Laser Induced Breakdown Spectroscopy and Neural
Networks-March
D
Marcos-Martinez, JA Ayala, RC Izquierdo-Hornillosa, F.J.
Manuel de Villenaa and J.O. Caceresa - Talanta,
Departamento de Química Analítica. Facultad de Ciencias
Químicas Universidad Complutense, Centro de Biología
Molecular ”Severo Ochoa”, Madrid Spain.
A method
based on Laser Induced Breakdown Spectroscopy (LIBS) and
neural networks (NNs) has been developed and applied to
the identification and discrimination of specific
bacteria strains. (Pseudomonas aeroginosa, Escherichia
coli and Salmonella
typhimurium).
Instant identification of the samples is achieved using
a spectral library, which was obtained by analysis using
a single laser pulse of representative samples and
treatment by neural networks. The samples used in this
study were divided into three groups, which were
prepared on three different days. The results obtained
allow the identification of the bacteria tested with a
certainty of over 95%, and show that only a difference
between the bacteria can cause identification.
Single-shot measurements were sufficient for clear
identification of the bacterial strains studied. The
method can be developed for automatic real time, fast,
reliable and robust measurements and can be packaged in
portable systems for non-specialist users.
... The spectrometer 9 system was a user-configured
miniature single-fiber system (BLUE-Wave, StellarNet,
Tampa, FL, 10 USA) with a gated CCD detector. A grating
of 300 l/mm was selected; a spectral resolution of 0.5
11 nm was achieved with a 7 m entrance slit.
Physical and Microbiological Characterisation of
Staphylococcus epidermidis Inactivation by Dielectric
Barrier Discharge Plasma-March
2011
A Helmke,
D Hoffmeister, F Berge, S Emmert, P Laspe, N Mertens, W
Vioel, and Klaus-Dieter Weltmann - Plasma Processes and
Polymers.
The inactivation of the Gram-positive
bacteria Staphylococcus
epidermidis (ATCC
12228) in its vegetative state was studied in
vitro after
exposure to cold atmospheric pressure plasma generated
by direct dielectric barrier discharge (DBD). Compared
to UV radiation at 254 nm,
plasma UV emission yielded no significant contribution
to bacterial inactivation. Analysis of bacterial growth
inhibition revealed a pH dependency on growth media.
Yet, measurements combined with numerical simulations
excluded the pH shift induced by plasma generated
reactive species as the main cause of bacterial
inactivation. Scanning electron microscopy (SEM) images
showed no alteration of cell walls, while fluorescence
microscopy revealed lethal damage to cell membranes even
after 1 s
treatment. When the cell membrane was already severely
damaged, also degradation of the bacterial DNA by plasma
treatment was found. We conclude that membrane damage
due to reactive oxygen species (ROS) and DNA degradation
are the main mechanisms of plasma-induced bacterial
death that is aggregated by milieu acidification. ...
Spectroscopy and Fluorescence Microscopy Optical
emission spectroscopy (OES) measurements of the plasma
and the UV source were carried out using a
concave grating miniature
spectrometer BLACK-Comet
(StellarNet Inc., Tampa, Florida) operating in the
wavelength region 190–850 nm.
Interferon-[ggr] links ultraviolet radiation to
melanomagenesis in mice
MR Zaidi, S Davis, FP
Noonan, C Graff-Cherry… - Nature 469, 548–553 (27
January 2011)
Cutaneous malignant melanoma is a highly
aggressive and frequently chemoresistant cancer, the
incidence of which continues to rise. Epidemiological
studies show that the major aetiological melanoma risk
factor is ultraviolet (UV) solar radiation, with the
highest risk associated with intermittent burning doses,
especially during childhood1, 2.
We have experimentally validated these epidemiological
findings using the hepatocyte growth factor/scatter
factor transgenic mouse model, which develops lesions in
stages highly reminiscent of human melanoma with respect
to biological, genetic and aetiological criteria, but
only when irradiated as neonatal pups with UVB, not UVA3, 4.
However, the mechanisms underlying UVB-initiated,
neonatal-specific melanomagenesis remain largely
unknown. Here we introduce a mouse model permitting
fluorescence-aided melanocyte imaging and isolation
following in
vivo UV
irradiation. We use expression profiling to show that
activated neonatal skin melanocytes isolated following a
melanomagenic UVB dose bear a distinct, persistent
interferon response signature, including genes
associated with immunoevasion. UVB-induced melanocyte
activation, characterized by aberrant growth and
migration, was abolished by antibody-mediated systemic
blockade of interferon-γ (IFN-γ),
but not type-I interferons. IFN-γ was
produced by macrophages recruited to neonatal skin by
UVB-induced ligands to the chemokine receptor Ccr2.
Admixed recruited skin macrophages enhanced transplanted
melanoma growth by inhibiting apoptosis; notably, IFN-γ blockade
abolished macrophage-enhanced melanoma growth and
survival. IFN-γ-producing
macrophages were also identified in 70% of human
melanomas examined. Our data reveal an unanticipated
role for IFN-γ in
promoting melanocytic cell survival/immunoevasion,
identifying a novel candidate therapeutic target for a
subset of melanoma patients.
... uniformity. The irradiance is measured with a
spectroradiometer (StellarNet) and
under standard conditions regularly produces an
irradiance of approximately 0.30 CIE-effective W m −2 .
Chitosan Films Doped with Gold Nanorods as
Laser-Activatable Hybrid Bioadhesives-
August 23, 2010
P Matteini, F Ratto, F Rossi, S Centi, L Dei, R Pini -
Advanced Materials
Biocompatible chitosan/gold
nanorods films are fabricated and tested as laser-activatable
adhesives. When exposed to near-infrared laser light the
nanoparticles carry out efficient photothermal
conversion, which activates the polar groups of chitosan
strands and mediates functional adhesion with a
biological tissue. This technology may enable a number
of key applications in medicine including tissue repair,
wound dressing and drug delivery. Read
more...
Modification of light sources for appropriate biological
action-
June 16 2010
R Kozakov,
H Schöpp, St Franke, C Stoll and D Kunz-
Leibniz Institute of Plasma Science and
Technology-
Charité–Universitymedicine
Berlin
The
impact of the non-visual action of light on the design
of novel light sources is discussed. Therefore possible
modifications of lamps dealing with spectral tailoring
and their action on melatonin suppression in usual life
situations are investigated. The results of melatonin
suppression by plasma lamps are presented. It is shown
that even short-time exposure to usual light levels in
working areas has an influence on the melatonin onset.
...
The luminance in their field of view was measured with a
calibrated luminance measurement
camera. The spectrum of light was recorded with
the help of a compact spectroradiometer
(EPP-2000, StellarNet- now
BLACK-Comet)
in the range between 300 and 800nm. ...Read
more...
In vivo
carotid artery closure by laser activation of
hyaluronan-embedded gold nanorods-
July 6, 2010
Paolo
Matteini, Fulvio Ratto, Francesca Rossi,
Giacomo Rossi,
Giuseppe Esposito, Alfredo Puca, Alessio Albanese, and
Giulio Maira-
Institute of Applied Physics “Nello
Carrara”, Italian National Research Council-
University of Camerino, Faculty of Veterinary
Medicine- Catholic University
School of Medicine, Institute of Neurosurgery
We prove the
first application of near-infrared-absorbing gold
nanorods (GNRs) for in vivo laser
closure of a rabbit carotid artery. GNRs are
first functionalized with a biopolymeric shell and then
embedded in hyaluronan, which gives a
stabilized and handy laser-activable formulation.
Four rabbits undergo closure of a 3-mm
longitudinal incision performed on the
carotid artery by means of a 810-nm diode
laser in conjunction with the topical application of the
GNRs composite. An effective surgery is
obtained by using a 40-W/cm2 laser power
density. The histological and electron microscopy
evaluation after a 30-day follow-up
demonstrates complete healing of the treated arteries
with full re-endothelization at the site of GNRs
application. The absence of microgranuloma
formation and/or dystrophic calcification is evidence
that no host reaction to nanoparticles
interspersed through the vascular tissue
occurred. The observation of a reshaping and associated
blue shift of the NIR absorption band of GNRs
after laser treatment supports the occurrence
of a self-terminating process, and thus of additional
safety of the minimally invasive laser procedure. This
study underlines the feasibility of using
GNRs for in vivo laser soldering
applications, which represents a step forward toward the
introduction of nanotechnology-based
therapies in minimally invasive clinical practices.
...
After irradiation, the samples were subject to
spectromicroscopy by a homemade setup composed
of a transmission microscope (model DM 2500 by
Leica Microsystems GmbH, Germany), a
visible-NIR spectrometer (model EPP200 by
Stellarnet Incorporated, Tampa, Florida ...
Read More...
A Synthetic Genetic Edge Detection Program- June
2009
Jeffrey J.
Tabor, Howard Salis, Zachary B. Simpson, Aaron A.
Chevalier, Anselm
Levskaya, Edward M. Marcotte,
Christopher A. Voigt, and Andrew D. Ellington-Department
of Pharmaceutical Chemistry, University of California
San Francisco, San Francisco,Center for Systems and
Synthetic Biology and Institute for Cell and Molecular
Biology, Department of Chemistry and Biochemistry,
University of Texas, Austin, TX.
Edge detection is a
signal processing algorithm common in artificial
intelligence and image recognition programs. We have
constructed a genetically encoded edge detection
algorithm that programs an isogenic community of E.coli
to sense an image of light, communicate to identify the
light-dark edges, and visually present the result of the
computation. The algorithm is implemented using multiple
genetic circuits. An engineered light sensor enables
cells to distinguish between light and dark regions. In
the dark, cells produce a diffusible chemical signal
that diffuses into light regions. Genetic logic gates
are used so that only cells that sense light and the
diffusible signal produce a positive output. A
mathematical model constructed from first principles and
parameterized with experimental measurements of the
component circuits predicts the performance of the
complete program. Quantitatively accurate models will
facilitate the engineering of more complex biological
behaviors and inform bottom-up studies of natural
genetic regulatory networks. The images projected onto
the slabs have power characteristics of 0.08 to 0.15W/m2
in the 620-680nm band as determined by a EPP2000C
Concave Grating spectrometer (StellarNet, Oldsmar, FL).
View PDF…
Cryptochrome 2 and phototropin 2 regulate resistance
protein-mediated viral defense by negatively regulating
an E3 ubiquitin ligase-
June 11, 2010
Rae-Dong Jeong, A. C. Chandra-Shekara,
Subhankar Roy Barman,
Duroy Navarre, Daniel F.
Klessig, Aardra Kachroo,
Pradeep Kachroo
Light harvested by plants
is essential for the survival of most life forms. This
light perception ability requires the activities of
proteins termed photoreceptors. We report a function for
photoreceptors in mediating resistance (R)
protein-derived plant defense. The blue-light
photoreceptors, cryptochrome (CRY) 2 and phototropin (PHOT)
2, are required for the stability of the R protein HRT,
and thereby resistance to Turnip Crinkle virus (TCV).
Exposure to darkness or blue-light induces degradation
of CRY2, and in turn HRT, resulting in susceptibility.
Overexpression of HRT can compensate for the absence of
PHOT2 but not CRY2. HRT does not directly associate with
either CRY2 or PHOT2 but does bind the
CRY2-/PHOT2-interacting E3 ubiquitin ligase, COP1.
Application of the proteasome inhibitor, MG132, prevents
blue-light-dependent degradation of HRT, consequently
these plants show resistance to TCV under blue-light. We
propose that CRY2/PHOT2 negatively regulate the
proteasome-mediated degradation of HRT, likely via COP1,
and blue-light relieves this repression resulting in HRT
degradation.
Read more...
Voltage-dependent Dynamic FRET Signals from the
Transverse Tubules in Mammalian Skeletal Muscle
Fibers-
December 2007
Marino DiFranco,
Joana Capote, Marbella Quiñonez, and Julio L.
Vergara
Two hybrid voltage-sensing
systems based on fluorescence resonance energy
transfer (FRET) were used to record membrane
potential changes in the transverse tubular
system (TTS) and surface membranes of adult mice
skeletal muscle fibers. Farnesylated EGFP or
ECFP (EGFP-F and ECFP-F) were used as immobile
FRET donors, and either non-fluorescent (dipicrylamine
[DPA]) or fluorescent (oxonol dye DiBAC4(5))
lipophilic anions were used as mobile energy
acceptors. Flexor digitorum brevis (FDB) muscles
were transfected by in vivo electroporation with
pEGFP-F and pECFP-F. Farnesylated fluorescent
proteins were efficiently expressed in the TTS
and surface membranes. Voltage-dependent optical
signals resulting from resonance energy transfer
from fluorescent proteins to DPA were named QRET
transients, to distinguish them from FRET
transients recorded using DiBAC4(5). The peak ΔF/F
of QRET transients elicited by action potential
stimulation is twice larger in fibers expressing
ECFP-F as those with EGFP-F (7.1% vs. 3.6%).
These data provide a unique experimental
demonstration of the importance of the spectral
overlap in FRET. The voltage sensitivity of QRET
and FRET signals was demonstrated to correspond
to the voltage-dependent translocation of the
charged acceptors, which manifest as nonlinear
components in current records. For DPA, both
electrical and QRET data were predicted by
radial cable model simulations in which the
maximal time constant of charge translocation
was 0.6 ms. FRET signals recorded in response to
action potentials in fibers stained with
DiBAC4(5) exhibit ΔF/F amplitudes as large as
28%, but their rising phase was slower than
those of QRET signals. Model simulations require
a time constant for charge translocation of 1.6
ms in order to predict current and FRET data.
Our results provide the basis for the potential
use of lipophilic ions as tools to test for fast
voltage-dependent conformational changes of
membrane proteins in the TTS. The fluorescence
spectra of EGFP-F and ECFP-F were measured in
vivo from isolated fibers mounted in the
fluorescence microscope described above but
additionally equipped with a fiber optic–coupled
spectrofluorimeter (EPP2000, StellarNet).
View PDF…
Membrane expression of EGFPF
and ECFP-F in FDB muscle fi bers. (A)
TPLSM image section obtained at the
medial plane of a
muscle fi ber expressing
EGFP-F. n denotes nucleus; arrowheads
point to the cytoplasmic side of a
nucleus; arrows point
toward areas of increased
fl uorescence close to the poles of
nuclei. (B)
Fluorescence intensity profi le obtained
from the area delimited by the white
rectangle in A. (C and
D) TPLSM image sections
of an FDB muscle
transfected with pECFP-F
and stained extracellularly with
di-8-ANEPPS. ECFP-F
and di-8-ANEPPS fl uorescence images
are shown in C and D, respectively.
(E) Superimposition of image sections in
C and D. (F) Normalized
fluorescence intensity
profi les measured from the area
delimited by the rectangles in Fig. 2, C
(cyan trace) and D (red trace). The
vertical calibration
bar is 20μm and applies to
all the images.
Characterization of the Effects of Aryl-azido Compounds
and UVA Irradiation on the Viral Proteins and
Infectivity of Human Immunodeficiency Virus Type 1-
July 12, 2010
Julie M. Belanger,
Yossef Raviv, Mathias
Viard, Michael Jason de la
Cruz, Kunio Nagashima,
Robert Blumenthal
Hydrophobic
UV-activatable compounds have been shown to partition
into the hydrophobic region of biological membranes to
selectively label transmembrane proteins, and to
inactivate enveloped viruses. Here, we analyze various
UV-activatable azido- and iodo-based hydrophobic
compounds for their ability to inactivate a
model-enveloped virus, human immunodeficiency virus
(HIV-1 MN). Treatment of HIV-1 with
1,5-diazidonapthalene (DAN), 1-iodo, 5-azidonaphthalene
(INA), 1-azidonaphthalene (AzNAP) or 4,4′-diazidobiphenyl
(DABIPH) followed by UVA irradiation for 2 min resulted
in complete viral inactivation, whereas treatment using
analogous non–azido-containing controls had no effect.
Incorporation of an azido moiety within these
hydrophobic compounds to promote photoinduced covalent
reactions with proteins was found to be the primary
mechanism
of viral inactivation for this class of compounds.
Prolonged UVA irradiation of the virus in the presence
of these azido compounds resulted in further
modifications of viral proteins, due to the generation
of reactive oxygen species, leading to aggregation as
visualized via Western blot analysis, providing
additional viral modifications that may inhibit viral
infectivity. Furthermore, inactivation using these
compounds resulted in the preservation of surface
antigenic structures (recognized by neutralizing
antibodies b12, 2g12 and 4e10), which is favorable for
the creation of vaccines from these inactivated virus
preparations....
polypropylene microfuge tubes. The UV emission from the
light source was measured
using a Stellarnet Spectroradiometer and was
found to have the mercury emission
lines where k > 335 nm (data not shown).
Read more...
Blue Light Induces Degradation of the Negative Regulator
Phytochrome Interacting Factor 1 to Promote
Photomorphogenic Development of Arabidopsis Seedlings
-Febuary 2009
Alicia
Castillon, Hui Shen1
and Enamul Huq
Phytochrome interacting factors (PIFs) are nuclear basic
helix-loop-helix (bHLH) transcription factors that
negatively regulate photomorphogenesis both in the dark
and in the light in Arabidopsis. The phytochrome (phy)
family of photoreceptors induces the rapid
phosphorylation and degradation of PIFs in response to
both red and far-red light conditions to promote
photomorphogenesis. Although phys have been shown to
function under blue light conditions, the roles of PIFs
under blue light have not been investigated in detail.
Here we show that PIF1 negatively regulates
photomorphogenesis at the seedling stage under blue
light conditions. pif1 seedlings displayed more open
cotyledons and slightly reduced hypocotyl length
compared to wild type under diurnal (12 hr light/12 hr
dark) blue light conditions. Double-mutant analyses
demonstrated that pif1phyA, pif1phyB, pif1cry1, and
pif1cry2 have enhanced cotyledon opening compared to the
single photoreceptor mutants under diurnal blue light
conditions. Blue light induced the rapid phosphorylation,
polyubiquitination, and degradation of PIF1 through the
ubi/26S proteasomal pathway. PIF1 interacted with phyA
and phyB in a blue light-dependent manner, and the
interactions with phys are necessary for the blue
light-induced degradation of PIF1. phyA played a
dominant role under pulses of blue light, while phyA,
phyB, and phyD induced the degradation of PIF1 in an
additive manner under prolonged continuous blue light
conditions. Interestingly, the absence of cry1 and cry2
enhanced the degradation of PIF1 under blue light
conditions. Taken together, these data suggest that PIF1
functions as a negative regulator of photomorphogenesis
under blue light conditions and that blue
light-activated phys induce the degradation of PIF1
through the ubi/26S proteasomal pathway to promote
photomorphogenesis. Light fluence rates were measured
using a spectroradiometer (model EPP2000; StellarNet,
Tampa, FL).
View PDF…
Wavelength specificity of the LED light sources used for
experiments in this study. Measured
by StellarNet
LED
Measurement system.
Interaction of
shade avoidance and auxin responses: a role for two
novel atypical bHLH proteins -
Oct 2007
Irma Roig-Villanova,
Jordi Bou-Torrent,
Anahit Galstyan,
Lorenzo Carretero-Paulet,
Sergi Portoles, Manuel Rodrı´guez-Concepcio, and Jaime F
Martı´nez-Garcı´a
Plants
sense the presence of potentially competing nearby
individuals as a reduction in the red to far-red ratio
of the incoming light. In anticipation of eventual
shading, a set of plant responses known as the shade
avoidance syndrome (SAS) is initiated soon after
detection of this signal by the phytochrome
photoreceptors. Here we analyze the function of
PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2, two
Arabidopsis thaliana genes rapidly upregulated after
simulated shade perception. These genes encode two
closely related atypical basic helix–loop–helix proteins
with no previously assigned function in plant
development. Using reverse genetic approaches, we show
that PAR1 and PAR2 act in the nucleus to broadly control
plant development, acting as negative regulators of a
variety of SAS responses, including seedling elongation
and photosynthetic pigment accumulation. Molecularly,
PAR1 and PAR2 act as direct transcriptional repressors
of two auxin-responsive genes, SMALL AUXIN UPREGULATED15
(SAUR15) and SAUR68. Additional results support that
PAR1 and PAR2 function in integrating shade and hormone
transcriptional networks, rapidly connecting phytochrome-sensed
light changes with auxin responsiveness. Fluence rates
were measured using an EPP2000 spectrometer (StellarNet
Inc.,Tampa, FL, USA).
View PDF…
Human Pigmentation
Variation: Evolution, Genetic
Basis, and
Implications for Public Health
Esteban J. Parra-
Department of Anthropology, University of Toronto at
Mississauga
Pigmentation, which is primarily
determined by the
amount, the type, and the distribution of
melanin, shows a remarkable diversity in
human populations, and
in this sense, it is an atypical trait.
Numerous genetic studies have indicated that the average
proportion of genetic
variation due to differences among
major continental groups is just 10–15%
of the total genetic
variation. In contrast, skin pigmentation shows
large differences among continental
populations. The
reasons for this discrepancy can be traced back
primarily to the
strong influence of
natural selection, which has
shaped the distribution of pigmentation
according to a
latitudinal gradient. Research during the last 5
years has
substantially increased our
understanding of the
genes involved in normal pigmentation
variation in human
populations. At least six genes have been
identified using
genotype/phenotype association studies and/or
direct functional assays, and there is
evidence indicating
that several additional genes may be playing a
role in skin, hair,
and iris pigmentation. The information that is
emerging from recent studies points to a
complex picture where
positive selection has been acting at different
genomic locations, and for some genes
only in certain
population groups. Diffuse reflectance
spectroscopy (DRS) is considered
the most versatile and accurate noninvasive
strategy to measure skin
pigmentation (Stamatas et al., 2004).
Skin reflectance curves
for individuals of European, East Asian, South Asian,
and African ancestry. Skin reflectance was measured on
the inner upper arm at 0.5-nm intervals along the
visible spectrum (400–700 nm) using a Stellarnet EPP2000
(now
BLACK-Comet)
reflectance spectrometer. Note the decrease in skin
reflectance in the green yellow wavelengths (540–580 nm)
due to hemoglobin absorption, which is particularly
evident in the curves of the individuals with the
highest skin reflectance.
Extinction Cross-Section Measurements of
Bacillus globigii Aerosols
Suzanne C. Walts, Craig
A. Mitchell, Michael E. Thomas, and Donald D. Duncan
In a
continuing series of experiments designed to
determine the spectral extinction
cross section of bacterial aerosols,
spectral transmittance was
measured as a function of particle
concentration, and
extinction cross sections were calculated.
Visible band measurements of Bacillus
globigii aerosols indicated a slight increase in
the extinction cross section with increasing
wavelength. The
extinction cross section was
estimated to be 2.58 (±0.25)10 8 cm 2 at
the 543-nm wavelength.
View PDF
Transmittance versus
wavelength for varying concentrations of Bacillus
Globigii. Curves are broadband spectrometer results and
boxes are laser results that calibrate the curves.
Mitochondrial succinic-semialdehyde
dehydrogenase of the γ-aminobutyrate shunt is
required to restrict levels of reactive oxygen
intermediates in plants
Nicolas Bouché,
Aaron Fait,
David Bouchez,
Simon G. Møller,
Hillel Fromm
The γ-aminobutyrate (GABA) shunt
is a metabolic pathway that bypasses two steps
of the tricarboxylic acid cycle, and it is
present in both prokaryotes and eukaryotes. In
plants the pathway is composed of the calcium/calmodulin-regulated
cytosolic enzyme glutamate decarboxylase and the
mitochondrial enzymes GABA transaminase and
succinic-semialdehyde dehydrogenase (SSADH). The
activity of the GABA shunt in plants is rapidly
enhanced in response to various biotic and
abiotic stresses. However the physiological role
of this pathway remains obscure. To elucidate
its role in plants, we analyzed Arabidopsis
T-DNA knockout mutants of SSADH, the ultimate
enzyme of the pathway. Four alleles of the
ssadh mutation were isolated, and these
exhibited a similar phenotype. When exposed to
white light (100 μmol of photons per m2
per s), they appear dwarfed with necrotic
lesions. Detailed spectrum analysis revealed
that UV-B has the most adverse effect on the
mutant phenotype, whereas photosynthetic active
range light has a very little effect. The
ssadh mutants are also sensitive to heat,
as they develop necrosis when submitted to such
stress. Moreover, both UV and heat cause a rapid
increase in the levels of hydrogen peroxide in
the ssadh mutants, which is associated
with enhanced cell death. Surprisingly, our
study also shows that trichomes are
hypersensitive to stresses in ssadh
mutants. Our work establishes a role for the
GABA shunt in preventing the accumulation of
reactive oxygen intermediates and cell death,
which appears to be essential for plant defense
against environmental stress.
Light
Spectrum Analysis. WT and
ssadh mutant seedlings were germinated and
grown under low-fluence white light (WL; 280–700 nm) for
4 weeks (short days) as described above followed by
exposure to different irradiation conditions. Seedlings
were irradiated for 7 days with Farnell 5-mm/T1¾
untainted clear-lens light-emitting diode rigs supplying
either monochromatic blue light (458 nm, 11 μmol·m-2·s-1)
or monochromatic red light (660 nm, 70 μmol·m-2·s-1).
For UV irradiation, seedlings were exposed to low-fluence
(30 μmol·m-2·s-1) or high-fluence
(70 μmol·m-2·s-1)
photosynthetically active radiation (PAR; 400–700 nm,
including UV-Amax 0.45 μmol·m-2·s-1
and UV-Bmax 0.012 μmol·m-2·s-1)
alone as a control, and supplemented with low- or high-fluence
UV-A (320–400 nm; 4.5 μmol·m-2·s-1
or 11.7 μmol·m-2·s-1) or with low-
or high-fluence UV-B (280–320 nm; 0.65 μmol·m-2·s-1
or 3.6 μmol·m-2·s-1) irradiation.
UV-A and UV-B were supplied by Philips TL20W/09N and
TL20W/01RS fluorescent tubes, respectively. All fluences
were measured with a StellarNet EPP2000 fiber optic
spectrometer (Tampa, FL).
Sensitivity
analysis of CDOM spectral slope in artificial
and natural samples: an application in the
central eastern Mediterranean Basin
Luca Bracchini, Antonio
Tognazzi, Arduino Massimo Dattilo, Franco Decembrini,
Claudio Rossi and Steven Arthur Loiselle
In the past two decades, optical properties of chromophoric dissolved organic matter (CDOM) in marine environments have been
extensively studied. Many of these studies report CDOM properties for the offshore environment where this complex mixture
of optically active compounds is strongly diluted. Nevertheless, autochthonous and allochthonous sources have been identified
and sinks related to photodegradation and bacterial activity have been demonstrated. The calculation of the spectral slope
of the CDOM absorption curve has been proven to be useful and is often reported. However, a rigorous uncertainty analysis
of the slope calculation is rarely reported. In this paper, we propose a method to evaluate the uncertainty of CDOM spectral
slope calculated between 270 and 400 nm, using both naturally sampled and artificial solutions. We use these results to study
the ultra-oligotrophic waters of the Mediterranean Sea (central eastern basin), where little is known about CDOM spatial distribution.
We show that dilutions of both artificial and natural samples produce a Gaussian distribution of spectral slopes, indicating
that consistent values may be determined, with a typical uncertainty of ±0.0004 nm−1 when absorption at 300 nm was greater then 0.1 m−1 (0.1 m pathlength). Comparing the distribution of spectral slopes from central eastern basin samples to a Gaussian distribution,
we show differences between measurements that were significantly different. These values allow us to distinguish possible
sources (algal derived CDOM), sinks (e.g. photo-bleaching) at different depths. We propose a subdivision of CDOM compounds
into refractory and semilabile/refractory pools and evaluate the CDOM spectral slope of algal derived CDOM released at or
near deep chlorophyll maximum.
Read more...
Optical Touch Pointer for Fluorescence Guided
Glioblastoma Resection Using
5-Aminolevulinic Acid
Neda Haj-Hosseini, MS,
Johan Richter, MD, Stefan Andersson-Engels, PhD, and
Karin Wardell, PhD- Department of Biomedical
Engineering, Linko¨ping University- Department of
Neurosurgery, Linkoping University Hospital- Department
of Physics, Lund University
Background and Objective: Total
tumor resection in
patients with
glioblastoma multiforme (GBM) is difficult to
achieve due to the tumor’s infiltrative
way of growing and
morphological similarity to the surrounding
functioning brain
tissue. The diagnosis is usually subjectively
performed using a
surgical microscope. The objective of this
study was to develop and evaluate a
hand-held optical
touch pointer using a fluorescence spectroscopy
system to
quantitatively distinguish healthy from
malignant brain tissue
intraoperatively.
Study Design/Materials and Methods: A
fluorescence
spectroscopy system with pulsed modulation was
designed considering
optimum energy
delivery to the tissue, minimal
photobleaching of PpIX and omission of
the ambient light
background in the operating room (OR).
5-Aminolevulinic acid
(5-ALA) of 5 mg/kg body weight was given to
the patients with a presumed
GBM prior to
surgery. During the
surgery a laser pulse at 405nm was delivered to
the tissue. PpIX in
glioblastoma tumor cells assigned with
peaks at 635 and 704nm was detected using
a fiber optical probe.
Results/Conclusion: By using the pulsed
fluorescence
spectroscopy,
PpIXfluorescence isquantitatively detected in
the GBM. An effective suppression of low
power lamp background
from the recorded spectra in addition to a
significant reduction of high power
surgical lights is
achieved.
Ablation of Liver Cancer Cells
in Vitro by a Plasma Needle
Xianhui Zhang, Maojin Li,
Rouli Zhou, Kecheng Feng,
and Size Yang-School of
Science, Changchun University ofScience and Technology-
Beijing National Laboratory for Condensed Matter
Physics, Institute of Physics, Chinese Academy
of Science- Health Science
Center, Department of Cell Biology, Peking University
A plasma needle using a dielectric
barrier discharge reactor at atmospheric pressure with a
funnel-shaped nozzle was developed. The
preliminary characteristics of the plume and
applications to the ablation
of cultured human hepatocellular
carcinoma HCC BEL-7402 cell line were
presented. The effect of oxygen, which was
injected into argon plasma afterglow region through a
steel tube, was studied. The efficiency of
argon-oxygen plasma depends sensitively on the oxygen
concentration in argon plasma. Large differences
between spectra in atmosphere and those in
Dulbecco’s modified eagle medium are found. It is
found that ultraviolet rays, O, OH, and Ar
radicals can reach the bottom of solution and act
on HCC cells and there is an optimum input power
to get the most radicals.
Process Monitoring and Quality
Control
Semi-Conductor
The
MPSS (Multi Probe Spectrophotometer System) is a
multi-channel process control monitor used in
semi-conductor fabrication and other real-time process
applications.
Alcohol
A dual
beam process monitor using "Neural Networks" to
measure the concentration of alcohol in a
process stream.
Film Deposition
A
multi-channel system used to
monitor silver film deposition on a
moving roll of plastic using transmission and
reflectance.
Dilatometer
The "Dilatometer"
analytical instrument designed for specifically
for polymer chemists.
Colorimeter
A
triple-channel SpectroColorimeter
used as a process Quality Control monitor for
plastic injection molding operations.
StellarNet Patents
A list of patents filed using
StellarNet spectrometers
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