Transport study of Berry's phase, the resistivity rule, and quantum Hall effect in graphite

Transport measurements indicate strong oscillations in the Hall-,$R_{xy}$, and the diagonal-, $R_{xx}$, resistances and exhibit Hall plateaus at the lowest temperatures, in three-dimensional Highly Oriented Pyrolytic Graphite (HOPG). At the same time, a comparative Shubnikov-de Haas-oscillations-based Berry's phase analysis indicates that graphite is unlike the GaAs/AlGaAs 2D electron system, the 3D n-GaAs epilayer, semiconducting $Hg_{0.8}Cd_{0.2}Te$, and some other systems. Finally, we observe the transport data to follow $B\times dR_{xy}/dB \approx - \Delta R_{xx}$. This feature is consistent with the observed relative phases of the oscillatory $R_{xx}$ and $R_{xy}$.Comment: 5 pages, 4 figure

Is Electroconvulsive Therapy Fading into Oblivion? - A Study of Ten Year Trends

Background: Despite proven efficacy, modified ECT has been variably used in the recent past, with data on the usage trend being scarce, worldwide. Aim: We aimed to do a time – series analysis to examine annual trends in modified ECT use in our tertiary teaching hospital in the last decade. Methods: A chart review was carried out on all patients who received m-ECT in our teaching hospital in the last ten years (2002 to 2011), and percentage of total inpatients receiving M-ECT each year was deduced. Along with number of ECT sessions given per year, details of demographic data, and indications for ECT were recorded. Results: In our study ECT was undersized as a treatment option, with only 1:13% of total inpatients having received ECT. Also it was noted that use began increasing from 2002, reaching a peak in 2006 (84% increase) followed by a downward trend, with a sharp decline since 2008 (61%decrease) and finally reaching a nadir in 2011 (69% decrease). Mean age of patients ranged from 31.28 to 40.1 years with a slightly high female preponderance in most year groups. The most common indication for ECT use was schizophrenia (47.8%) followed by, depression (38.9%). Conclusion: Although, our study finding is in line with the downward trend of ECT utilization rates reported worldwide, the nature and magnitude of decline cannot be explained nor compared globally due to variations, inaccuracies and heterogeneity of ECT data currently available. Further, factors responsible for such trends should become focus of future research

Wear and corrosion resistant properties of electrodeposited Ni composite coating containing Al2O3-TiO2 composite powder

Electrodeposited Ni composite coatings containing ceramic particles have been widely investigated due to their improved mechanical, wear and corrosion resistant properties over plain nickel coatings. The application of one of the most widely studied plasma spray powder, Al2O3–13 wt-%TiO2, has not been explored in electrodeposited nickel composites. In the present study, Ni/Al2O3–13 wt-%TiO2 coatings have been electrodeposited using physically mixed commercial Al2O3 and TiO2 powders. The microhardness, wear and corrosion resistant properties of the coatings have been investigated. It was found that the area fraction of particles incorporated in the nickel matrix was very high at lower current density, and the corresponding composite coating exhibited a maximum microhardness (∼580 HK). Interestingly, corrosion resistance of Ni/Al2O3–13 wt-%TiO2 composite coating was similar to that reported for Ni/TiO2. The wear behaviour of Ni/Al2O3–13 wt-%TiO2 coating was in between Ni/Al2O3 and Ni/TiO2 coatings and thus exhibited a synergistic effect of the properties of Al2O3 and TiO2 powders

EXPERIMENTAL STUDY ON BEHAVIOUR OF COLD FORMED STEEL LIPPED ANGLE COLUMNS

This article reports the experimental work on the behavior of cold formed steel lipped angle columns performed with pinned end conditions under axial compression. In this work three different types of equal and unequal plain and lipped angle sections were chosen with a total of 12 specimens. The column lengths were taken as 1200 mm. The material properties of these sections were found by conducting Tensile Coupon test. The section geometries were selected in order to take account of all types of buckling modes. The column strengths determined from the experiment was examined with the design strength attained from Direct Strength Method in North American Specification and with the Numerical results (ABAQUS) for Cold formed steel structures. Finally, an appropriate design proposal was suggested for DSM to forecast the ultimate strength of cold formed steel columns

DEVELOPMENT AND VALIDATION OF BIOANALYTICAL HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF CILNIDIPINE AND NEBIVOLOL IN HUMAN PLASMA

Objective: To develop and validate a modified isocratic reversed-phase high performance liquid chromatographic (RP-HPLC) method for determination of cilnidipine and nebivolol in human plasma to be used for pharmacokinetic studies.Methods: The drug was extracted from plasma samples by direct protein precipitation technique using acetonitrile. Amlodipine was used as internal standard (IS). Samples were analyzed on BDS C18 column (250 x 4.6 mm, 5 µm), applying ortho phosphoric acid (0.1%): Acetonitrile, at a ratio of 45:55 v/v in isocratic mode as a mobile phase at a flow rate of 1 ml/min to attain adequate resolution. Separations were performed at room temperature and monitored at a wavelength of 260 nm after injection of 50μl samples into the HPLC system. The analytical method was validated according to FDA bioanalytical method validation guidance. The method was applied for pharmacokinetic study of cilnidipine and nebivolol tablets-10 mg and 5 mg were administered as a single dose to 6 healthy male rabbits under fasting condition. Twelve blood samples were withdrawn from each rabbit over 24 h periods. From the plasma concentration-time data of each individual, the pharmacokinetic parameters; Cmax, Tmax, AUC0-t and AUC0-∞ were calculated.Results: A peak area was obtained for cilnidipine and nebivolol at 3.943 and 4.719 min retention time respectively. Linearity was established at a concentration range of 0.20-20 μg/ml (r2=0.999, n=8) for cilnidipine and 0.02-2 μg/ml (r2=0.999, n=8) for nebivolol. The lower limit of quantitation (LLOQ) was identifiable and reproducible at 0.2μg/ml for cilnidipine and 0.02 μg/ml for nebivolol. The coefficients of variation (%cv) of the intra-day and inter-day precision of cilnidipine at 600, 1000 and 1600ng/ml levels were found to be 6.90%, 6.19%, 5.22%; and 7.74%, 6.54%, 5.77%, respectively, which are lower than the accepted criteria limits (15-20 %). The mean recovery (%) cilnidipine at 600, 1000, and 1600ng/ml was found to be 101.03%, 99.27% and 104.87%, and for nebivolol 60, 100, and 160 ng/ml was found to be 106.13%, 107.03% and 98.06% respectively. Stability at different conditions and in autosampler was also established. The mean pharmacokinetic parameters; Cmax, Tmax, AUC0-t and AUC0-∞ were 6 ng/ml, 2 hr, 96.76 mg. hr/ml, 63.45 mg. hr/ml for cilnidipine and 5.8ng/ml, 2hr, 74.78 mg. hr/ml, 100.25 mg. hr/ml for nebivolol respectively.Conclusion: The present analytical method was found to be specific, sensitive, accurate and precise for quantification of cilnidipine and nebivolol in human plasma. It can be successively applied for pharmacokinetics, bioavailability and bioequivalence studies

Contracting for Services in the U.S. Army: An Empirical Study of Current Management Practices

An analysis of the implications of different deficiencies of services acquisitions in the U.S. Army, as well as the effectiveness of current contract management processes and recommendations for improvement.This article presents the results of our empirical study of current management practices in services acquisition in the U.S. Army. In this study, we developed and used a web-based survey to collect primary data on the acquisition strategy, procurement methods, and contract types used at army installations. Specifically, we studied the current management practices in such areas as life cycle approach, project management, organization/management structure, and training provided to services acquisition personnel