588 research outputs found

    First principles study of structural, electronic and optical properties of half-heusler alloys LIMGN, NaMGN and KMGN

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    In this study, we performed our calculations using the full-potential linearized-augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code based on DFT. The generalized gradient functional with the Wu-Cohen (WC) parameterization was used to evaluate the structural, electronic, optical and thermoelectric properties of the materials under this study. We have calculated the structural parameters and our obtained results are in good agreement with available experimental and previous theory calculations. The density of states and band structure figures have been calculated and analyzed. The optical properties that covered by dielectric function, absorption coefficient, refractive index, extinction coefficient, reflectivity and energy-loss function have been calculated and analyzed in a range energy from 0eV to 30eV

    Gender differences in the association between adiposity and probable major depression: a cross-sectional study of 140,564 UK Biobank participants

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    <b>Background</b><p></p> Previous studies on the association between adiposity and mood disorder have produced contradictory results, and few have used measurements other than body mass index (BMI). We examined the association between probable major depression and several measurements of adiposity: BMI, waist circumference (WC), waist-hip-ratio (WHR), and body fat percentage (BF%).<p></p> <b>Methods</b><p></p> We conducted a cross-sectional study using baseline data on the sub-group of UK Biobank participants who were assessed for mood disorder. Multivariate logistic regression models were used, adjusting for potential confounders including: demographic and life-style factors, comorbidity and psychotropic medication.<p></p> <b>Results</b><p></p> Of the 140,564 eligible participants, evidence of probable major depression was reported by 30,145 (21.5%). The fully adjusted odds ratios (OR) for obese participants were 1.16 (95% confidence interval (CI) 1.12, 1.20) using BMI, 1.15 (95% CI 1.11, 1.19) using WC, 1.09 (95% CI 1.05, 1.13) using WHR and 1.18 (95% CI 1.12, 1.25) using BF% (all p <0.001). There was a significant interaction between adiposity and gender (p = 0.001). Overweight women were at increased risk of depression with a dose response relationship across the overweight (25.0-29.9 kg/m2), obese I (30.0-34.9 kg/m2), II (35.0-39.9 kg/m2) and III (≥40.0 kg/m2) categories; fully adjusted ORs 1.14, 1.20, 1.29 and 1.48, respectively (all p < 0.001). In contrast, only obese III men had significantly increased risk of depression (OR 1.29, 95% CI 1.08, 1.54, p = 0.006).<p></p> <b>Conclusion</b><p></p> Adiposity was associated with probable major depression, irrespective of the measurement used. The association was stronger in women than men. Physicians managing overweight and obese women should be alert to this increased risk

    Global Health Education: a cross-sectional study among German medical students to identify needs, deficits and potential benefits (Part 1 of 2: Mobility patterns & educational needs and demands)

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    <p>Abstract</p> <p>Background</p> <p>In recent years, education and training in global health has been the subject of recurring debate in many countries. However, in Germany, there has been no analysis of the educational needs or demands of medical students, or the educational deficits or potential benefits involved in global health education. Our purpose is to analyse international health elective patterns of medical students enrolled at German universities and assess whether or how they prepare for their electives abroad. We examine the exposure of medical students enrolled at German universities to training courses in tropical medicine or global health and assess students' perceived needs and demands for education in global health.</p> <p>Methods</p> <p>Cross-sectional study among medical students in Germany including all 36 medical schools during the second half of the year 2007. All registered medical students were eligible to participate in the study. Recruitment occurred via electronic mailing-lists of students' unions. We developed a web-based, semi-structured questionnaire to capture students' international mobility patterns, preparation before electives, destination countries, exposure to and demand for global health learning opportunities.</p> <p>Results</p> <p>1126 online-replies were received and analysed from all registered medical students in Germany (N = 78.067). 33.0% of all respondents (370/1126) declared at least one international health elective and of these, 36.0% (133/370) completed their electives in developing countries. 36.0% (131/363) did not prepare specifically at all, 59.0% (214/363) prepared either by self-study or declared a participation in specific preparation programmes. 87.8% of 5<sup>th </sup>and 6<sup>th </sup>year students had never participated in a global health course and 72.6% (209/288) had not completed a course in tropical medicine. 94.0% (861/916) endorsed the idea of introducing global health into medical education.</p> <p>Conclusion</p> <p>Students in our sample are highly mobile during their studies. International health electives are common, also in developing countries. Formal preparation beyond self-study is virtually non-existent amongst our sample and the participation rate in courses of tropical medicine or global health is appallingly low. We have identified unmet perceived needs and the demand for more learning opportunities in global health in our sample, urging for reforms to adjust curricula to a globalising world.</p

    In silico modeling of the specific inhibitory potential of thiophene-2,3-dihydro-1,5-benzothiazepine against BChE in the formation of β-amyloid plaques associated with Alzheimer's disease

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    <p>Abstract</p> <p>Background</p> <p>Alzheimer's disease, known to be associated with the gradual loss of memory, is characterized by low concentration of acetylcholine in the hippocampus and cortex part of the brain. Inhibition of acetylcholinesterase has successfully been used as a drug target to treat Alzheimer's disease but drug resistance shown by butyrylcholinesterase remains a matter of concern in treating Alzheimer's disease. Apart from the many other reasons for Alzheimer's disease, its association with the genesis of fibrils by β-amyloid plaques is closely related to the increased activity of butyrylcholinesterase. Although few data are available on the inhibition of butyrylcholinesterase, studies have shown that that butyrylcholinesterase is a genetically validated drug target and its selective inhibition reduces the formation of β-amyloid plaques.</p> <p>Rationale</p> <p>We previously reported the inhibition of cholinesterases by 2,3-dihydro-1, 5-benzothiazepines, and considered this class of compounds as promising inhibitors for the cure of Alzheimer's disease. One compound from the same series, when substituted with a hydroxy group at C-3 in ring A and 2-thienyl moiety as ring B, showed greater activity against butyrylcholinesterase than to acetylcholinesterase. To provide insight into the binding mode of this compound (Compound A), molecular docking in combination with molecular dynamics simulation of 5000 ps in an explicit solvent system was carried out for both cholinesterases.</p> <p>Conclusion</p> <p>Molecular docking studies revealed that the potential of Compound A to inhibit cholinesterases was attributable to the cumulative effects of strong hydrogen bonds, cationic-π, π-π interactions and hydrophobic interactions. A comparison of the docking results of Compound A against both cholinesterases showed that amino acid residues in different sub-sites were engaged to stabilize the docked complex. The relatively high affinity of Compound A for butyrylcholinesterase was due to the additional hydrophobic interaction between the 2-thiophene moiety of Compound A and Ile69. The involvement of one catalytic triad residue (His438) of butyrylcholinesterase with the 3'-hydroxy group on ring A increases the selectivity of Compound A. C-C bond rotation around ring A also stabilizes and enhances the interaction of Compound A with butyrylcholinesterase. Furthermore, the classical network of hydrogen bonding interactions as formed by the catalytic triad of butyrylcholinesterase is disturbed by Compound A. This study may open a new avenue for structure-based drug design for Alzheimer's disease by considering the 3D-pharmacophoric features of the complex responsible for discriminating these two closely-related cholinesterases.</p

    Combinatorial nuclear level density by a Monte Carlo method

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    We present a new combinatorial method for the calculation of the nuclear level density. It is based on a Monte Carlo technique, in order to avoid a direct counting procedure which is generally impracticable for high-A nuclei. The Monte Carlo simulation, making use of the Metropolis sampling scheme, allows a computationally fast estimate of the level density for many fermion systems in large shell model spaces. We emphasize the advantages of this Monte Carlo approach, particularly concerning the prediction of the spin and parity distributions of the excited states, and compare our results with those derived from a traditional combinatorial or a statistical method. Such a Monte Carlo technique seems very promising to determine accurate level densities in a large energy range for nuclear reaction calculations.Comment: 30 pages, LaTex, 7 figures (6 Postscript figures included). Fig. 6 upon request to the autho

    Increased prevalence of methicillin-resistant Staphylococcus aureus nasal colonization in household contacts of children with community acquired disease

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    <p>Abstract</p> <p>Background</p> <p>To measure Methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) nasal colonization prevalence in household contacts of children with current community associated (CA)-MRSA infections (study group) in comparison with a group of household contacts of children without suspected <it>Staphylococcus aureus </it>infection (a control group).</p> <p>Methods</p> <p>This is a cross sectional study. Cultures of the anterior nares were taken. Relatedness of isolated strains was tested using pulse field gel electrophoresis (PFGE).</p> <p>Results</p> <p>The prevalence of MRSA colonization in the study group was significantly higher than in the control group (18/77 (23%) vs 3/77 (3.9%); p ≤ 0.001). The prevalence of SA colonization was 28/77 (36%) in the study group and 16/77 (21%) in the control group (p = 0.032). The prevalence of SA nasal colonization among patients was 6/24 (25%); one with methicillin-susceptible <it>S. aureus </it>(MSSA) and 5 with MRSA. In the study (patient) group, 14/24 (58%) families had at least one household member who was colonized with MRSA compared to 2/29 (6.9%) in the control group (p = 0.001). Of 69 total isolates tested by PFGE, 40 (58%) were related to USA300. Panton-Valetine leukocidin (PVL) genes were detected in 30/52 (58%) tested isolates. Among the families with ≥1 contact colonized with MRSA, similar PFGE profiles were found between the index patient and a contact in 10/14 families.</p> <p>Conclusions</p> <p>Prevalence of asymptomatic nasal carriage of MRSA is higher among household contacts of patients with CA-MRSA disease than control group. Decolonizing such carriers may help prevent recurrent CA-MRSA infections.</p

    Association of adiposity and mental health functioning across the lifespan:Findings from understanding society (The UK household longitudinal study)

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    Background: Evidence on the adiposity-mental health associations is mixed, with studies finding positive, negative or no associations, and less is known about how these associations may vary by age. Objective: To examine the association of adiposity -body mass index (BMI), waist circumference (WC) and percentage body fat (BF%)- with mental health functioning across the adult lifespan. Methods: Data from 11,257 participants (aged 18+) of Understanding Society: the UK Household Longitudinal Study (waves 2 and 3, 5/2010-7/2013) were employed. Regressions of mental health functioning, assessed by the Mental Component Summary (MCS-12) and the General Health Questionnaire (GHQ-12), on adiposity measures (continuous or dichotomous indicators) were estimated adjusted for covariates. Polynomial age-adiposity interactions were estimated. Results: Higher adiposity was associated with poorer mental health functioning. This emerged in the 30s, increased up to mid-40s (all central adiposity and obesity-BF% measures) or early 50s (all BMI measures) and then decreased with age. Underlying physical health generally accounted for these associations except for central adiposity, where associations remained statistically significant from the mid-30s to50s. Cardiovascular, followed by arthritis and endocrine, conditions played the greatest role in attenuating the associations under investigation. Conclusions: We found strong age-specific patterns in the adiposity-mental health functioning association that varied across adiposity measures. Underlying physical health had the dominant role in attenuating these associations. Policy makers and health professionals should target increased adiposity, mainly central adiposity, as it is a risk factor for poor mental health functioning in those aged between mid-30s to 50 years

    Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory

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    Solar neutrinos from the decay of 8^8B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons. The CC reaction is sensitive exclusively to nu_e's, while the ES reaction also has a small sensitivity to nu_mu's and nu_tau's. The flux of nu_e's from ^8B decay measured by the CC reaction rate is \phi^CC(nu_e) = 1.75 +/- 0.07 (stat)+0.12/-0.11 (sys.) +/- 0.05(theor) x 10^6 /cm^2 s. Assuming no flavor transformation, the flux inferred from the ES reaction rate is \phi^ES(nu_x) = 2.39+/-0.34 (stat.)+0.16}/-0.14 (sys) x 10^6 /cm^2 s. Comparison of \phi^CC(nu_e) to the Super-Kamiokande Collaboration's precision value of \phi^ES(\nu_x) yields a 3.3 sigma difference, providing evidence that there is a non-electron flavor active neutrino component in the solar flux. The total flux of active ^8B neutrinos is thus determined to be 5.44 +/-0.99 x 10^6/cm^2 s, in close agreement with the predictions of solar models.Comment: 6 pages (LaTex), 3 figures, submitted to Phys. Rev. Letter

    Spectral Distribution Studies of fp shell nuclei with modified Kuo--Brown Interaction

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    The structure of nuclei in the lower half of fp shell is investigated by the spectral distribution method using the modified Kuo-Brown interaction. This interaction recently showed success in reproducing observed properties through detailed shell model studies. Spectral distribution studies avoid explicit diagonalization and hold promise for applications to astrophysics.Comment: Latex, 19 pages, 1 figure, to be published in Physical Review
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