Coulomb blockade and quantum tunnelling in the low-conductivity phase of granular metals

We study the effects of Coulomb interaction and inter-grain quantum tunnelling in an array of metallic grains using the phase-functional approach for temperatures $T$ well below the charging energy $E_{c}$ of individual grains yet large compared to the level spacing in the grains. When the inter-grain tunnelling conductance $g\gg1$, the conductivity $\sigma$ in $d$ dimensions decreases logarithmically with temperature ($\sigma/\sigma_{0}\sim1-\frac{1}{2\pi gd}\ln(gE_{c}/T)$), while for $g\to0$, the conductivity shows simple activated behaviour ($\sigma \sim \exp(-E_c/T)$). We show, for bare tunnelling conductance $g \gtrsim 1$, that the parameter $\gamma \equiv g(1-2/(g\pi)\ln(gE_{c}/T))$ determines the competition between charging and tunnelling effects. At low enough temperatures in the regime $1\gtrsim \gamma \gg 1/\sqrt{\beta E_{c}}$, a charge is shared among a finite number $N=\sqrt{(E_{c}/T)/\ln(\pi/2\gamma z)}$ of grains, and we find a soft activation behaviour of the conductivity, $\sigma\sim z^{-1}\exp(-2\sqrt{(E_{c}/T)\ln(\pi/2\gamma z)})$, where $z$ is the effective coordination number of a grain.Comment: 11 pages REVTeX, 3 Figures. Appendix added, replaced with published versio

Medium/high field magnetoconductance in chaotic quantum dots

The magnetoconductance G in chaotic quantum dots at medium/high magnetic fluxes Phi is calculated by means of a tight binding Hamiltonian on a square lattice. Chaotic dots are simulated by introducing diagonal disorder on surface sites of L x L clusters. It is shown that when the ratio W/L is sufficiently large, W being the leads width, G increases steadily showing a maximum at a flux Phi_max ~ W. Bulk disordered ballistic cavities (with an amount of impurities proportional to L) does not show this effect. On the other hand, for magnetic fluxes larger than that for which the cyclotron radius is of the order of L/2, the average magnetoconductance inceases almost linearly with the flux with a slope proportional to W^2, shows a maximum and then decreases stepwise. These results closely follow a theory proposed by Beenakker and van Houten to explain the magnetoconductance of two point contacts in series.Comment: RevTeX including six postscript figure

Development of Readout Interconnections for the Si-W Calorimeter of SiD

The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.Comment: 8 pages + title, 6 figure

Analysis of spontaneously reported adverse drug reactions to pharmacovigilance cell of a tertiary care hospital

Background: The objective of the study was to study the clinical patterns, causality and severity of adverse drug reactions in a tertiary care hospital.Methods: Total 131 ADR forms were collected from January 2012 to December 2012 and evaluated. Patient’s characteristics, ADR and drug characteristics, causality, severity and preventability of collected ADR were analyzed.Results: Total 131 ADR forms were evaluated. Male patient experiencing ADR were more (73, 55.7%) than female (58, 44.2%). Adult patients (12-60 years) experienced 110 (84%) ADR followed by pediatric patients (60 years) 10 (7.63%). Antimicrobial were the most common group of drugs responsible for ADR followed by NSAIDs and antipsychotic group.Conclusions: Present study shows lack of awareness among health care professionals for reporting of an ADR. Training and collaboration of health care professionals are needed for improvement in ADR reporting. Appropriate feedback from ADR reporting will help in selection of drug and promotes safer use of drugs

ESTIMATION OF TOTAL PHENOLIC AND FLAVONOID CONTENT OF POLYHERBAL FORMULATION DASHANG LEPA

Background: Indian system of medicine mainly based on polyherbal compound to treat various types of diseases. Dashang lepa is one of the prestigious formulation of ten indigenous drugs which are having predominantly anti-inflammatory properties and clinically used in inflammatory swelling like boil, furunculosis, cellulitis, erysipelas etc. As several reports are on various individual phytochemical, phenolic and flavonoid content but none is having study of polyherbal compound Dashang lepa. Objectives: Total phenolic and total flavonoid content were studied of alcoholic extract of Dashang lepa. Method: Methanolic extraction was done by hot percolation method through soxhlet apparatus. Phenolic content was estimated using Follin ciocalteau reagent, flavonoid using aluminum chloride (2%) reagent as quercetin equivalent. Results: Estimation of total phenolic and total flavonoid content showed that Dashang lepa extract was having phenolic content (15.8±1.14) ug Gallic acid equivalents (GAE) and flavonoid content (22.4±2.54) in ug of quercetin equivalents (QE)

Preparation of Electronics grade Bismuth, Antimony, Tellurium, Cadmium and Zinc by Vaccum distillation and Zone refining

APART from the usual importance of bismuth, antimony, tellurium, cadmium & zinc in thechemical, metallurgical, cosmetic, pharmaceutical and paint industries , these materials in their high purity forms (9999 to 99999 %) have recently acquired special significance in the electronics industry for semiconductor and various other applications. The major applications of these electronics grade materials in the electronic industry are : Bismuth : solders and thermo-electric devices, Antimony : semi-conductor devices + for crystal doping), photocell cathodes, Tellurium Compound semi-conductors Cadmium Solders mostly for semi-conductor processing and for compound semi-conductors, such as CdS. Zinc : dopant and diffusant in semi-conductors

Knowledge and attitude towards emergency contraception among undergraduate medical students

Background: Studying the knowledge and attitude of medical students towards emergency contraception, as they are the future medical professionals and they will serve as the main channel for providing proper knowledge and making positive impression of it in general population. The objective of the study was to assess the knowledge and attitude of undergraduate medical students towards emergency contraception.Methods: Medical students were given pre-validated questionnaire and divided in two groups. Group A students did not learn about emergency contraception, whereas group B students learnt about it. Interview of both groups were conducted separately. For group A, 1 hour seminar was conducted and after 7 days, same questionnaire was provided again for data collection.Results: 154 students were included in group A whereas 162 students in group B. Average knowledge and attitude was significantly increased after seminar in group A [knowledge 41±16.88% vs. 59.32±14.46%; P<0.05; attitude 36.24±10.93 vs. 41.5±10.87; P<0.05]. Average knowledge of group B students was 64.73±12.15% whereas average attitude score was 42.9±9.79. Amongst all, 86.4%, 87% and 89.3% students were not able to describe about emergency contraception, different methods and advantages of intra-uterine device as emergency contraception, respectively. There are 82.1% students showed positive interest in learning more about emergency contraception and 70.1% agreed to recommend its use in future. Students having good knowledge showed more positive attitude towards emergency contraception [r= 0.41, P<0.05].Conclusions: Students have poor knowledge of special issues arises with emergency contraception. Proper attention should be given to these aspects during their teaching. Students have shown their positive interest to learn more about emergency contraception. Objective based seminar will be more helpful in improving knowledge and attitude