607 research outputs found
A comparative study of overlap and staggered fermions in QCD
We perform a comparative study of the infrared properties of overlap and
staggered fermions in QCD. We observe that the infrared spectrum of the APE/HYP
improved staggered Dirac operator develops a four-fold near-degeneracy and is
in quantitative agreement with the infrared spectrum of the overlap operator.
The near-degeneracy allows us to identify the zero modes of the staggered
operator and we find that the number of zero modes is in line with the
topological index of the overlap operator.Comment: Talk presented at Lattice2004(chiral), Fermilab, June 21-26, 2004, 3
pages, 2 figure
Optimal Band Selection for the Calculation of Planck Mean Absorption Coefficients
Radiative heat transfer is a major heat loss mechanism in thermal plasmas generated during arc flashes/faults in switchgear applications or during high current interruption in low voltage circuit breakers. A common way to calculate the radiation balance is by means of approximate non-gray radiation models like P1 or discrete ordinates (DOM), where the frequency dependent absorption and emission are described in a number of frequency intervals (bands) using a constant absorption coefficient in each band. Current work is focused on finding the optimal number of bands as well as band interval boundaries that provide a reasonable level of accuracy in comparison to a full spectral solution. An optimization procedure has been applied to different SF6 and copper vapor gas mixtures for an assumed temperature profile. Radiation model results using optimized band averaged absorption coefficients as well as spectral values are provided and discussed for the exemplary temperature profile
Radiative Properties and Numerical Modeling of C4F7N-CO2-O2 Thermal Plasma
C4F7N and C4F7N-CO2 mixtures are considered as alternatives to SF6 for use in medium voltage gas insulated switchgear applications (GIS), due to the low global warming potential and good dielectric properties of C4F7N. Current work is focused on the calculation of radiative properties (absorption coefficients) of C4F7N-CO2 thermal plasma and computational fluid dynamics (CFD) simulations of free burning C4F7N-CO2 arcs that are stabilized by natural convection. Absorption coefficients of C4F7N-CO2 plasma used in the CFD model are derived from spectral absorption coefficients by Planck averaging. An optimization procedure has been applied to find the optimal number of spectral bands as well as spectral band interval boundaries. Radiation and flow model results for C4F7N-CO2 in comparison to SF6 and air are provided and discussed
Transport Properties of Thermal Plasma Containing Fluoro-Nitrile (C4F7N)-Based Gas Mixtures
Gas mixtures containing fluoro-nitriles C<sub>4</sub>F<sub>7</sub>N or fluoro-ketones C<sub>5</sub>F<sub>10</sub>O as minority components (<20%) have been identified as promising alternatives to SF<sub>6</sub> in medium voltage gas-insulated switchgear (GIS) applications, because of their low Global Warming Potential together with their dielectric strength values being comparable to SF<sub>6</sub>. The buffer gases in such fluoro-nitrile or fluoro-ketone based gas mixtures are usually N<sub>2</sub>, O<sub>2</sub>, CO<sub>2</sub>, or air. In this contribution, we provide calculation results of transport properties, assuming local thermodynamic equilibrium (LTE), of thermal plasma containing following gas mixtures: C<sub>4</sub>F<sub>7</sub>N-CO<sub>2</sub> and C<sub>4</sub>F<sub>7</sub>N-CO<sub>2</sub>-O<sub>2</sub>. The modifications in the thermodynamic and transport properties upon the addition of oxygen to the C<sub>4</sub>F<sub>7</sub>N-CO<sub>2</sub> mixtures in the temperature range 300&thinsp;K-30&thinsp;kK at 1&thinsp;bar are provided and discussed. These properties have been utilized to calculate the plasma temperature profile for a free-burning arc in a companion paper
Colorimetric method of Ziprasidone In bulk and in pharmaceutical dosage forms
ABSTRACT A new simple, sensitive and precise visible spectrophotometric method has been developed for the determination of Ziprasidone in bulk and in pharmaceutical formulations. This method is based on the hydrolysis of Ziprasidone, followed by diazotization and coupling with N-(1-naphthyl) ethylene diamine dihydrochloride to form an azo dye which was estimated at an absorption maximum of 540nm (pink color). This method has the linearity in the concentration range of 2-10µg/ml. This method is statistically evaluated for efficacy
Matrix Metalloproteinase-8 Mediates the Unfavorable Systemic Impact of Local Irradiation on Pharmacokinetics of Anti-Cancer Drug 5-Fluorouracil
Concurrent chemoradiation with 5-fluorouracil (5-FU) is widely accepted for cancer treatment. However, the interactions between radiation and 5-FU remain unclear. Here, we evaluated the influence of local irradiation on the pharmacokinetics of 5-FU in rats. The single-fraction radiation was delivered to the whole pelvic fields of Sprague-Dawley rats after computerized tomography-based planning. 5-FU at 100 mg/kg was prescribed 24 hours after radiation. A high-performance liquid chromatography system was used to measure 5-FU in the blood. Matrix metalloproteinase-8 (MMP-8) inhibitor I was administered to examine whether or not RT modulation of 5-FU pharmacokinetic parameters could be blocked. Compared with sham-irradiated controls, whole pelvic irradiation reduced the area under the concentration versus time curve (AUC) of 5-FU in plasma and, in contrast, increased in bile with a radiation dose-dependent manner. Based on protein array analysis, the amount of plasma MMP-8 was increased by whole pelvic irradiation (2.8-fold by 0.5 Gy and 5.3-fold by 2 Gy) in comparison with controls. Pretreatment with MMP-8 inhibitor reversed the effect of irradiation on AUC of 5-FU in plasma. Our findings first indicate that local irradiation modulate the systemic pharmacokinetics of 5-FU through stimulating the release of MMP-8. The pharmacokinetics of 5-FU during concurrent chemoradiaiton therapy should be rechecked and the optimal 5-FU dose should be reevaluated, and adjusted if necessary, during CCRT
A community based field research project investigating anaemia amongst young children living in rural Karnataka, India: a cross sectional study
<p>Abstract</p> <p>Background</p> <p>Anaemia is an important problem amongst young children living in rural India. However, there has not previously been a detailed study of the biological aetiology of this anaemia, exploring the relative contributions of iron, vitamin B12, folate and Vitamin A deficiency, inflammation, genetic haemoglobinopathy, hookworm and malaria. Nor have studies related these aetiologic biological factors to household food security, standard of living and child feeding practices. Barriers to conducting such work have included perceived reluctance of village communities to permit their children to undergo venipuncture, and logistical issues. We have successfully completed a community based, cross sectional field study exploring in detail the causes of anaemia amongst young children in a rural setting.</p> <p>Methods and design</p> <p>A cross sectional, community based study. We engaged in extensive community consultation and tailored our study design to the outcomes of these discussions. We utilised local women as field workers, harnessing the capacity of local health workers to assist with the study. We adopted a programmatic approach with a census rather than random sampling strategy in the village, incorporating appropriate case management for children identified to have anaemia. We developed a questionnaire based on existing standard measurement tools for standard of living, food security and nutrition. Specimen processing was conducted at the Primary Health Centre laboratory prior to transport to an urban research laboratory.</p> <p>Discussion</p> <p>Adopting this study design, we have recruited 415 of 470 potentially eligible children who were living in the selected villages. We achieved support from the community and cooperation of local health workers. Our results will improve the understanding into anaemia amongst young children in rural India. However, many further studies are required to understand the health problems of the population of rural India, and our study design and technique provide a useful demonstration of a successful strategy.</p
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Effects of DHA- Rich n-3 Fatty Acid Supplementation on Gene Expression in Blood Mononuclear Leukocytes: The OmegAD Study
Background: Dietary fish oil, rich in n-3 fatty acids (n-3 FAs), e. g. docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), regulate inflammatory reactions by various mechanisms, e. g. gene activation. However, the effects of long-term treatment with DHA and EPA in humans, using genome wide techniques, are poorly described. Hence, our aim was to determine the effects of 6 mo of dietary supplementation with an n-3 FA preparation rich in DHA on global gene expression in peripheral blood mononuclear cells. Methods and Findings: In the present study, blood samples were obtained from a subgroup of 16 patients originating from the randomized double-blind, placebo-controlled OmegAD study, where 174 Alzheimer disease (AD) patients received daily either 1.7 g of DHA and 0.6 g EPA or placebo for 6 months. In blood samples obtained from 11 patients receiving n-3 FA and five placebo, expressions of approximately 8000 genes were assessed by gene array. Significant changes were confirmed by real-time PCR. At 6 months, the n-3 FAs group displayed significant rises of DHA and EPA plasma concentrations, as well as up-and down-regulation of nine and ten genes, respectively, was noticed. Many of these genes are involved in inflammation regulation and neurodegeneration, e. g. CD63, MAN2A1, CASP4, LOC399491, NAIP, and SORL1 and in ubiqutination processes, e. g. ANAPC5 and UBE2V1. Down-regulations of ANAPC5 and RHOB correlated to increases of plasma DHA and EPA levels. Conclusions: We suggest that 6 months of dietary n-3 FA supplementatio
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