1,028 research outputs found

    First-principle density-functional calculation of the Raman spectra of BEDT-TTF

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    We present a first-principles density-functional calculation for the Raman spectra of a neutral BEDT-TTF molecule. Our results are in excellent agreement with experimental results. We show that a planar structure is not a stable state of a neutral BEDT-TTF molecule. We consider three possible conformations and discuss their relation to disorder in these systems.Comment: 3 pages, 2 figures, submitted to the proceedings of ISCOM 200

    Theoretical infra-red, Raman, and Optical spectra of the B36N36 cage

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    The B36N36 fullerene-like cage structure was proposed as candidate structure for the single-shell boron-nitride cages observed in electron-beam irradiation experiment. We have performed all electron density functional calculations, with large polarized Gaussian basis sets, on the B36N36 cage. We show that the cage is energetically and vibrationally stable. The infra-red, Raman and optical spectra are calculated. The predicted spectra, in combination with experimentally measured spectra, will be useful in conclusive assignment of the proposed B36N36 cage. The vertical and adiabatic ionization potentials as well as static dipole polarizability are also reported.Comment: RevTex, 4 pages, 4 figures (TO appear in Physical Review A (Breif Report)

    Photo-excitation of a light-harvesting supra-molecular triad: a Time-Dependent DFT study

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    We present the first time-dependent density-functional theory (TDDFT) calculation on a light harvesting triad carotenoid-diaryl-porphyrin-C60. Besides the numerical challenge that the ab initio study of the electronic structure of such a large system presents, we show that TDDFT is able to provide an accurate description of the excited state properties of the system. In particular we calculate the photo-absorption spectrum of the supra-molecular assembly, and we provide an interpretation of the photo-excitation mechanism in terms of the properties of the component moieties. The spectrum is in good agreement with experimental data, and provides useful insight on the photo-induced charge transfer mechanism which characterizes the system.Comment: Accepted for publication on JPC, March 09th 200

    Participatory cotton breeding for organic and low input farming in Central India

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    Up to 80% of world’s organic cotton is produced in India. However, involved producers are facing increased difficulties to find suitable cultivars. Few hybrids selected for high input farming and genetically-modified (GM) cotton, which is explicitly excluded in organic farming, are presently dominating the Indian seed market. In addition farmers have lost their traditional knowledge on seed production and hybrid seed needs to be purchased each season

    Role of biochemical markers in the prediction of osteopenia and osteoporosis in men and women of Sikkim, India

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    Background: Osteoporosis being a silently progressing disease, the real challenge is to identify the individual at high risk of osteoporosis. Many bone turnover marker have been associated with bone loss even before occurrence of any changes in bone structure. Therefore, this study was aim to evaluate the predictive value of bone turnover marker by correlating with low bone density.Methods: This was a case control study conducted in Sikkim Manipal Institute of Medical Sciences, India. A total of 300 subjects (150 case and 150 control) both male and female between the age group of 35- 65 were enrolled. We measure one bone formation marker serum osteocalcin and two resorption marker urine hydroxyproline (OHP) and urine N- terminal telopeptides of type I collagen (NTX). Calcaneal QUS device (GE Lunar Achilles Express heel- densitometer) was used to determine the bone density.Results: A significant difference of the bone markers i.e. hydroxyproline, NTx and osteocalcin were observed between cases and control of men and women with P<0.001. These variables statistically significantly predicts bone density with F (3, 71) = 5,671, P= 0.002, R2= 0.193 and F (3, 71) = 5.292, P= 0.002, R2= 0.183 in women and men respectively.Conclusions: Study showed that bone turnover markers are able to predict low bone mass. Resorption markers NTx and OHP were the main predictor in men whereas OHP and formation marker Osteocalcin in women. Therefore, BTM measurement along with BMD can provide useful information about the changes in the bone mass which will help to predict the risk of osteoporosis

    PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 2: User's manual (version 3.0)

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    A comprehensive description of user problem definition for the PAN AIR (Panel Aerodynamics) system is given. PAN AIR solves the 3-D linear integral equations of subsonic and supersonic flow. Influence coefficient methods are used which employ source and doublet panels as boundary surfaces. Both analysis and design boundary conditions can be used. This User's Manual describes the information needed to use the PAN AIR system. The structure and organization of PAN AIR are described, including the job control and module execution control languages for execution of the program system. The engineering input data are described, including the mathematical and physical modeling requirements. Version 3.0 strictly applies only to PAN AIR version 3.0. The major revisions include: (1) inputs and guidelines for the new FDP module (which calculates streamlines and offbody points); (2) nine new class 1 and class 2 boundary conditions to cover commonly used modeling practices, in particular the vorticity matching Kutta condition; (3) use of the CRAY solid state Storage Device (SSD); and (4) incorporation of errata and typo's together with additional explanation and guidelines

    Mice lacking C1q or C3 show accelerated rejection of minor H disparate skin grafts and resistance to induction of tolerance

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    Complement activation is known to have deleterious effects on organ transplantation. On the other hand, the complement system is also known to have an important role in regulating immune responses. The balance between these two opposing effects is critical in the context of transplantation. Here, we report that female mice deficient in C1q (C1qa(−/−)) or C3 (C3(−/−)) reject male syngeneic grafts (HY incompatible) at an accelerated rate compared with WT mice. Intranasal HY peptide administration, which induces tolerance to syngeneic male grafts in WT mice, fails to induce tolerance in C1qa(−/−) or C3(−/−) mice. The rejection of the male grafts correlated with the presence of HY D(b)Uty-specific CD8(+) T cells. Consistent with this, peptide-treated C1qa(−/−) and C3(−/−) female mice rejecting male grafts exhibited more antigen-specific CD8(+)IFN-γ(+) and CD8(+)IL-10(+) cells compared with WT females. This suggests that accumulation of IFN-γ- and IL-10-producing T cells may play a key role in mediating the ongoing inflammatory process and graft rejection. Interestingly, within the tolerized male skin grafts of peptide-treated WT mice, IFN-γ, C1q and C3 mRNA levels were higher compared to control female grafts. These results suggest that C1q and C3 facilitate the induction of intranasal tolerance

    Kondo resonances and anomalous gate dependence of electronic conduction in single-molecule transistors

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    We report Kondo resonances in the conduction of single-molecule transistors based on transition metal coordination complexes. We find Kondo temperatures in excess of 50 K, comparable to those in purely metallic systems. The observed gate dependence of the Kondo temperature is inconsistent with observations in semiconductor quantum dots and a simple single-dot-level model. We discuss possible explanations of this effect, in light of electronic structure calculations.Comment: 5 pages, four figures. Supplementary material at http://www.ruf.rice.edu/~natelson/publications.htm

    Magnetic moment and anisotropy in FenCom clusters

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    Electronic structure calculations of FenCom (n+m=5 and 13) are used to examine the effects of alloying on the magnetic moment and magnetic anisotropies. Our density-functional studies show that many mixed clusters have moments comparable to or higher than the pure clusters. The mixed clusters, however, have very low anisotropies and could be ideal as soft magnetic materials. It is shown that shape, composition, and compositional ordering must be considered for optimization of anisotropy energies

    Evaluation of the efficacy of tamsulosin with or without deflazacort for stone clearance after extracorporeal shockwave lithotripsy for upper ureteral and renal calculi

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    Background: Medical expulsive therapy in the form of alpha blockers, corticosteroids, calcium channel blockers is being used with success for medical treatment of lower ureteric calculus. Adjunctive use of these therapeutic agents in post extracorporeal shockwave lithotripsy period is also being tried.With this background, we evaluated the efficacy of tamsulosin with or without deflazacort for various outcome factors after ESWL of upper ureteral and renal calculi.Methods: A Prospecive study during period from February 2014 to April 2015 including a total of 90 patients with solitary upper ureteral or renal calculus who underwent ESWL was conducted. Patients were divided into three groups. Group A(30 patients) were given standard therapy (analgesics and antibiotics for 5 days), Group B (30 patients) were given standard plus tamsulosin (0.4 mg once daily) for 4 weeks and Group C (30 patients) were given standard therapy plus tamsulosin (0.4 mg once daily) and deflazacort (6 mg twice daily) for 4 weeks . Patients were evaluated at 2 and 4 weeks post ESWL with X ray KUB and USG.Results: At the end of 4 weeks, 10, 17, and 26 patients in group A, B and C respectively cleared their stones. Out of these 2, 6 and 19 patients in group A, B and C respectively cleared their stones in first 2 weeks. Clearance in group C was significantly higher as compared to group A and B.Conclusions: Addition of alpha-blocker tamsulosin along with deflazacort post ESWL for renal and upper ureteric calculi increases the stone expulsion rate and reduces the expulsion duration as shown by highly statistically significant results in group C.
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