495 research outputs found
Temperature Dependence of the Cyclotron Mass in n-Type CdS
Recent cyclotron resonance experiments in n-type CdS at ultra-high magnetic
fields have revealed a pronounced maximum of the electron cyclotron mass as a
function of temperature. In order to interpret these data, we calculate the
magneto-absorption spectra of polarons in n-CdS using the arbitrary-coupling
approach. We show that in high magnetic fields the polaron effects beyond the
weak-coupling approximation clearly reveal themselves in the magneto-optical
absorption even at relatively small values of the Froehlich coupling constant.
In particular, those effects result in a non-monotonous behaviour of the
cyclotron mass as a function of temperature. We extend the theory to take into
account a combined effect of several scattering mechanisms on the
magneto-absorption spectra. The extended theory allows us to interpret
quantitatively the experimentally observed behaviour of the cyclotron mass in
CdS.Comment: 4 pages, 3 figures, E-mail addresses: [email protected],
[email protected]
A catalytic combustion-type CO gas sensor incorporating aluminum nitride as an intermediate heat transfer layer for accelerated response time
A catalytic combustion-type carbon monoxide gas sensor exhibiting good
sensing performance even at moderate temperatures was previously developed
by employing a Pt loaded CeO2–ZrO2–SnO2 solid solution as
the CO oxidizing catalyst. The addition of aluminum nitride as an
intermediate heat transfer layer between the Pt coil and the CO oxidizing
catalyst drastically accelerated the response of this device to CO at
temperatures as low as 70 °C
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Code-sharing in Cost-of-illness Calculations: An Application to Antibiotic-Resistant Bloodstream Infections
Background: More data-driven evidence is needed on the cost of antibiotic resistance. Both Japan and England have large surveillance and administrative datasets. Code sharing of costing models enables reduced duplication of effort in research.
Objective: To estimate the burden of antibiotic-resistant Staphylococcus aureus bloodstream infections (BSIs) in Japan, utilizing code that was written to estimate the hospital burden of antibiotic-resistant Escherichia coli BSIs in England. Additionally, the process in which the code-sharing and application was performed is detailed, to aid future such use of code-sharing in health economics.
Methods: National administrative data sources were linked with voluntary surveillance data within the Japan case study. R software code, which created multistate models to estimate the excess length of stay associated with different exposures of interest, was adapted from previous use and run on this dataset. Unit costs were applied to estimate healthcare system burden in 2017 international dollars (I6,392 per S. aureus BSI, whilst oxacillin resistance was associated with an additional I$8,155.
Conclusions: S. aureus resistance profiles other than methicillin may substantially impact hospital costs. The sharing of costing models within the field of antibiotic resistance is a feasible way to increase burden evidence efficiently, allowing for decision makers (with appropriate data available) to gain rapid cost-of-illness estimates
DNA Nucleobase Synthesis at Titan Atmosphere Analog by Soft X-rays
Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of
N2 and CH4 and includes traces of many simple organic compounds. This
atmosphere also partly consists of haze and aerosol particles which during the
last 4.5 gigayears have been processed by electric discharges, ions, and
ionizing photons, being slowly deposited over the Titan surface. In this work,
we investigate the possible effects produced by soft X-rays (and secondary
electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic
photochemistry. The experiments have been performed inside a high vacuum
chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian
Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were
performed by a Fourier transform infrared spectrometer. The infrared spectra
have presented several organic molecules, including nitriles and aromatic CN
compounds. After the irradiation, the brownish-orange organic residue (tholin)
was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic
resonance (1H NMR) techniques, revealing the presence of adenine (C5H5N5), one
of the constituents of the DNA molecule. This confirms previous results which
showed that the organic chemistry on the Titan surface can be very complex and
extremely rich in prebiotic compounds. Molecules like these on the early Earth
have found a place to allow life (as we know) to flourish.Comment: To appear in Journal of Physical Chemistry A.; Number of pages: 6;
Number of Figures: 5; Number of Tables: 1; Number of references:49; Full
paper at http://pubs.acs.org/doi/abs/10.1021/jp902824
Thermal stability of amorphous sugar matrix, dried from methanol, as an amorphous solid dispersion carrier
[EN] Developing a technique to disperse hydrophobic ingredients homogeneously in a water-soluble solid matrix (solid dispersion) is one of the topics that have been extensively investigated in the pharmaceutical and food industries. Recently, we have devised a novel solid dispersion technique (surfactant-free solid dispersion), in which a preliminarily amorphized sugar was dissolved in an organic media containing hydrophobic component, without using any surface active substances, and then vacuum dried into the amorphous solid mixture [Food Chem., 197 (2016) 1136; Mol. Pharm., 14 (2017) 791]. In this study, the physicochemical properties, especially thermal stability of the surfactant-free amorphous solid dispersion, were investigated.Imamura, K.; Takeda, K.; Yamamoto, K.; Imanaka, H.; Ishida, N. (2018). Thermal stability of amorphous sugar matrix, dried from methanol, as an amorphous solid dispersion carrier. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 997-1004. https://doi.org/10.4995/IDS2018.2018.7716OCS997100
Organic chemistry of NH<sub>3</sub> and HCN induced by an atmospheric abnormal glow discharge in N<sub>2</sub>-CH<sub>4</sub> mixtures
The formation of the chemical products produced in an atmospheric glow discharge fed by a N2-CH4 gas mixture has been studied using Fourier Transform InfraRed (FTIR) and Optical Emission Spectrometry (OES). The measurements were carried out in a flowing regime at ambient temperature and pressure with CH4 concentrations ranging from 0.5% to 2%. In the recorded emission spectra the lines of the second positive system CN system and the first negative system of N2 were found to be the most intensive but atomic Hα, Hβ, and C (247 nm) lines were also observed. FTIR-measurements revealed HCN
and NH3 to be the major products of the plasma with traces of C2H2. These same molecules have been detected in Titan's atmosphere and the present experiments may provide some novel insights into the
chemical and physical mechanisms prevalent in Titan's atmosphere with these smaller species believed to be the precursors of heavier organic species in Titan's atmosphere and on its surface
Pathological Investigation of Congenital Bicuspid Aortic Valve Stenosis, Compared with Atherosclerotic Tricuspid Aortic Valve Stenosis and Congenital Bicuspid Aortic Valve Regurgitation
Congenital bicuspid aortic valve (CBAV) is the main cause of aortic stenosis (AS) in young adults. However, the histopathological features of AS in patients with CBAV have not been fully investigated.We examined specimens of aortic valve leaflets obtained from patients who had undergone aortic valve re/placement at our institution for severe AS with CBAV (n = 24, CBAV-AS group), severe AS with tricuspid aortic valve (n = 24, TAV-AS group), and severe aortic regurgitation (AR) with CBAV (n = 24, CBAV-AR group). We compared the histopathological features among the three groups. Pathological features were classified using semi-quantitative methods (graded on a scale 0 to 3) by experienced pathologists without knowledge of the patients' backgrounds. The severity of inflammation, neovascularization, and calcium and cholesterol deposition did not differ between the CBAV-AS and TAV-AS groups, and these four parameters were less marked in the CBAV-AR group than in the CBAV-AS (all p<0.01). Meanwhile, the grade of valvular fibrosis was greater in the CBAV-AS group, compared with the TAV-AS and CBAV-AR groups (both p<0.01). In AS patients, thickness of fibrotic lesions was greater on the aortic side than on the ventricular side (both p<0.01). Meanwhile, thickness of fibrotic lesions was comparable between the aortic and ventricular sides in CBAV-AR patients (p = 0.35).Valvular fibrosis, especially on the aortic side, was greater in patients with CBAV-AS than in those without, suggesting a difference in the pathogenesis of AS between CBAV and TAV
Effective weakly supervised semantic frame induction using expression sharing in hierarchical hidden Markov models
We present a framework for the induction of semantic frames from utterances
in the context of an adaptive command-and-control interface. The system is
trained on an individual user's utterances and the corresponding semantic
frames representing controls. During training, no prior information on the
alignment between utterance segments and frame slots and values is available.
In addition, semantic frames in the training data can contain information that
is not expressed in the utterances. To tackle this weakly supervised
classification task, we propose a framework based on Hidden Markov Models
(HMMs). Structural modifications, resulting in a hierarchical HMM, and an
extension called expression sharing are introduced to minimize the amount of
training time and effort required for the user.
The dataset used for the present study is PATCOR, which contains commands
uttered in the context of a vocally guided card game, Patience. Experiments
were carried out on orthographic and phonetic transcriptions of commands,
segmented on different levels of n-gram granularity. The experimental results
show positive effects of all the studied system extensions, with some effect
differences between the different input representations. Moreover, evaluation
experiments on held-out data with the optimal system configuration show that
the extended system is able to achieve high accuracies with relatively small
amounts of training data
Biogenesis of mitochondrial porin
We review here the present knowledge about the pathway of import and assembly of porin into mitochondria and compare it to those of other mitochondrial proteins. Porin, like all outer mitochondrial membrane proteins studied so far is made as a precursor without a cleavble lsquosignalrsquo sequence; thus targeting information must reside in the mature sequence. At least part of this information appears to be located at the amino-terminal end of the molecule. Transport into mitochondria can occur post-translationally. In a first step, the porin precursor is specifically recognized on the mitochondrial surface by a protease sensitive receptor. In a second step, porin precursor inserts partially into the outer membrane. This step is mediated by a component of the import machinery common to the import pathways of precursor proteins destined for other mitochondrial subcompartments. Finally, porin is assembled to produce the functional oligomeric form of an integral membrane protein wich is characterized by its extreme protease resistance
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