8 research outputs found
Analysis of Fiber-Enhanced Raman Gas Sensing Based on Raman Chemical Imaging
Fiber enhanced Raman spectroscopy
(FERS) is an arising new technique
for versatile highly sensitive and selective multigas analysis in
various applications, such as environmental monitoring and medical
breath diagnosis. In this study, the performance of FERS was thoroughly
studied with the help of a specially designed multichannel Raman chemical
imaging. Several types of hollow core photonic crystal fibers were
thoroughly analyzed in terms of their performance in light confinement
and sensitive gas sensing. The optimal fiber length for Raman gas
sensing was found to be 15 cm in our spectroscopic system. To separate
the Raman scattering of the target gas molecules from the background
generated by the silica microstructure of the fiber, the optimal diameter
of a spatial filter was analyzed and quantified as Ø3.9 μm,
which balances the suppression of the silica background and the attenuation
of the gas signal, originating from different regions in the plane
of the fiber end-face. To achieve an easy-to-use gas monitoring system
with stable performance, an automated coupling-method was developed,
to simplify the alignment of the FERS setup. The optimized design
of the FERS setup has remarkable potential for highly sensitive, miniaturized,
easy-to-use, and versatile gas sensing
Ultrasensitive Fiber Enhanced UV Resonance Raman Sensing of Drugs
Fiber
enhanced UV resonance Raman spectroscopy is introduced for
chemical selective and ultrasensitive analysis of drugs in aqueous
media. The application of hollow-core optical fibers provides a miniaturized
sample container for analyte flow and efficient light-guiding, thus
leading to strong light–analyte interactions and highly improved
analytical sensitivity with the lowest sample demand. The Raman signals
of the important antimalaria drugs chloroquine and mefloquine were
strongly enhanced utilizing deep UV and electronic resonant excitation
augmented by fiber enhancement. An experimental design was developed
and realized for reproducible and quantitative Raman fiber sensing,
thus the enhanced Raman signals of the pharmaceuticals show excellent
linear relationship with sample concentration. A thorough model accounts
for the different effects on signal performance in resonance Raman
fiber sensing, and conclusions are drawn how to improve fiber enhanced
Raman spectroscopy (FERS) for chemical selective analysis with picomolar
sensitivity
Fiber-Enhanced Raman Multigas Spectroscopy: A Versatile Tool for Environmental Gas Sensing and Breath Analysis
Versatile
multigas analysis bears high potential for environmental
sensing of climate relevant gases and noninvasive early stage diagnosis
of disease states in human breath. In this contribution, a fiber-enhanced
Raman spectroscopic (FERS) analysis of a suite of climate relevant
atmospheric gases is presented, which allowed for reliable quantification
of CH<sub>4</sub>, CO<sub>2</sub>, and N<sub>2</sub>O alongside N<sub>2</sub> and O<sub>2</sub> with just one single measurement. A highly
improved analytical sensitivity was achieved, down to a sub-parts
per million limit of detection with a high dynamic range of 6 orders
of magnitude and within a second measurement time. The high potential
of FERS for the detection of disease markers was demonstrated with
the analysis of 27 nL of exhaled human breath. The natural isotopes <sup>13</sup>CO<sub>2</sub> and <sup>14</sup>N<sup>15</sup>N were quantified
at low levels, simultaneously with the major breath components N<sub>2</sub>, O<sub>2</sub>, and <sup>12</sup>CO<sub>2</sub>. The natural
abundances of <sup>13</sup>CO<sub>2</sub> and <sup>14</sup>N<sup>15</sup>N were experimentally quantified in very good agreement to theoretical
values. A fiber adapter assembly and gas filling setup was designed
for rapid and automated analysis of multigas compositions and their
fluctuations within seconds and without the need for optical readjustment
of the sensor arrangement. On the basis of the abilities of such miniaturized
FERS system, we expect high potential for the diagnosis of clinically
administered <sup>13</sup>C-labeled CO<sub>2</sub> in human breath
and also foresee high impact for disease detection via biologically
vital nitrogen compounds
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Frequency and Management of Sleep Disturbance in Adults with Atopic Dermatitis: A Systematic Review
<p><b>Article full text</b></p>
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<p>The full text of this article can
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Have we reached proton beam therapy dosimetric limitations? – A novel robust, delivery-efficient and continuous spot-scanning proton arc (SPArc) therapy is to improve the dosimetric outcome in treating prostate cancer
Have we reached proton beam therapy dosimetric limitations? – A novel robust, delivery-efficient and continuous spot-scanning proton arc (SPArc) therapy is to improve the dosimetric outcome in treating prostate cance
Guselkumab for the Treatment of Psoriasis: A Review of Phase III Trials
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features will be thoroughly peer reviewed to ensure the content is of the
highest scientific standard and all features are marked as ‘peer reviewed’ to
ensure readers are aware that the content has been reviewed to the same level
as the articles they are being presented alongside. Moreover, all sponsorship
and disclosure information is included to provide complete transparency and
adherence to good publication practices. This ensures that however the content
is reached the reader has a full understanding of its origin. No fees are
charged for hosting additional open access content.</p>
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Magnesium Fluoride Electron-Selective Contacts for Crystalline Silicon Solar Cells
In this study, we present a novel
application of thin magnesium fluoride films to form electron–selective
contacts to <i>n</i>-type crystalline silicon (c-Si). This
allows the demonstration of a 20.1%-efficient c-Si solar cell. The
electron-selective contact is composed of deposited layers of amorphous
silicon (∼6.5 nm), magnesium fluoride (∼1 nm), and aluminum
(∼300 nm). X-ray photoelectron spectroscopy reveals a work
function of 3.5 eV at the MgF<sub>2</sub>/Al interface, significantly
lower than that of aluminum itself (∼4.2 eV), enabling an Ohmic
contact between the aluminum electrode and <i>n</i>-type
c-Si. The optimized contact structure exhibits a contact resistivity
of ∼76 mΩ·cm<sup>2</sup>, sufficiently low for a
full-area contact to solar cells, together with a very low contact
recombination current density of ∼10 fA/cm<sup>2</sup>. We
demonstrate that electrodes functionalized with thin magnesium fluoride
films significantly improve the performance of silicon solar cells.
The novel contacts can potentially be implemented also in organic
optoelectronic devices, including photovoltaics, thin film transistors,
or light emitting diodes
The percentage changes of size versus SUV with the axes cross the metabolic response line of -25% and anatomical response line of -30%
<p><b>Copyright information:</b></p><p>Taken from "Correlating metabolic and anatomic responses of primary lung cancers to radiotherapy by combined F-18 FDG PET-CT imaging"</p><p>http://www.ro-journal.com/content/2/1/18</p><p>Radiation Oncology (London, England) 2007;2():18-18.</p><p>Published online 23 May 2007</p><p>PMCID:PMC1892564.</p><p></p> Legends, SUV = standard uptake value, Plus sign = local control, cross = deceased, circle = local failure on follow up