An innovative technique for electronic transport model of group-III nitrides.

An optimized empirical pseudopotential method (EPM) in conjunction with virtual crystal approximation (VCA) and the compositional disorder effect is used for simulation to extract the electronic material parameters of wurtzite nitride alloys to ensure excellent agreement with the experiments. The proposed direct bandgap results of group-III nitride alloys are also compared with the different density functional theories (DFT) based theoretical results. The model developed in current work, significantly improves the accuracy of calculated band gaps as compared to the ab-initio method based results. The physics of carrier transport in binary and ternary nitride materials is investigated with the help of in-house developed Monte Carlo algorithms for solution of Boltzmann transport equation (BTE) including nonlinear scattering mechanisms. Carrier-carrier scattering mechanisms defined through Coulomb-, piezoelectric-, ionized impurity-, surface roughness-scattering with acoustic and intervalley scatterings, all have been given due consideration in present model. The direct and indirect energy bandgap results have been calibrated with the experimental data and use of symmetric and asymmetric form factors associated with respective materials. The electron mobility results of each binary nitride material have been compared and contrasted with experimental results under appropriate conditions and good agreement has been found between simulated and experimental results.

Ondansetron and Granisetron for prevention of postoperative nausea and vomiting following laparoscopic cholecystectomy.

INTRODUCTION: Laparoscopic surgeries are known to be associated with a higher incidence of postoperative nausea and vomiting (PONV). Prophylaxis of PONV is usually achieved with a single-dose antiemetic drug administered during the surgical procedure. The aim of this study was to compare the antiemetic efficacy of two different 5-hydroxytryptamine-3 (5HT3) receptor antagonists, ondansetron and granisetron when given prophylactically to patients undergoing laparoscopic cholecystectomy. METHODS: It was a randomized, double blind study, conducted in 90 patients. Patients were divided into two groups: Group A and Group B with 45 patients in each group. Patients in groupA were given 100 microgram/kg ondansetron intravenously (IV), and patients in Group B were given 40 microgram/kg granisetron. Both the drugs were diluted in 10 ml of 0.9% NaCl and were given at the end of surgery. The standard general anesthetic technique was administered to all the patients. Episodes of nausea, retching and vomiting were assessed during the first 24 hours after anesthesia. RESULTS: There was no statistically significant difference for demographic data and duration of surgery among the two groups (P>0.05). Evaluated nausea and vomiting scores in the first 3 hours period revealed that each of the drugs had a similar antiemetic effect (P>0.05). Between 4-12 hours also the episodes of nausea, retching as well as vomiting were statistically insignificant in both the groups. In the last 12 hours, episodes of nausea, retching and vomiting were significantly higher in ondansetron group. CONCLUSIONS: Granisetron, when given prophylactically, resulted in a significantly lower incidence of PONV than ondansetron in the first 24 hours.