BVRI CCD photometric standards in the field of GRB 990123

The CCD magnitudes in Johnson $BV$ and Cousins $RI$ photometric passbands are determined for 18 stars in the field of GRB 990123. These measurements can be used in carrying out precise CCD photometry of the optical transient of GRB 990123 using differential photometric techniques during non--photometric sky conditions. A comparison with previous photometry indicates that the present photmetry is more precise.Comment: Tex file, 5 pages with 1 figure. Bull. Astron. Society India, Vol. 27 (accepted

Antidiabetic activity of Plumeria rubra L. in normal and alloxan induced diabetic mice

Background: Diabetes mellitus is a major source of morbidity in developed countries. In spite of the introduction of hypoglycemic agents, diabetes and related complications continue to be a major medical problem. Our present study aims to investigate the antidiabetic activity of aqueous extract of plumeria rubra (PR) in experimental animals.Methods: PR extract was subjected to antidiabetic study in alloxan induced diabetic model at three-dose levels 100,200 and 400 mg/kg respectively. It was also tested for hypoglycemic activity at same dose levels. Diabetes was induced by alloxan monohydrate (150 mg/kg, i.p.). PR extracts and standard drug glibenclamide (10 mg/kg, p.o.) was administered to animals for 28 days. The blood glucose, serum cholesterol, serum triglyceride, high density lipoprotein, low density lipoprotein, glycosylated hemoglobin. Body weights were assessed in the experimental animals. Histopathological observations during 28 days treatment were also evaluated.Results: PR extract induced significant reduction (P<0.001) in fasting blood glucose levels in normal and alloxan-induced diabetic mice. Significant differences were observed in serum lipid profiles, glycosylated haemoglobin by extract treated-diabetic animals, when compared with the diabetic control and normal animals. The protective effect of PR was also evident from the histopathological examination on pancreas, liver and kidney. It reduced the injuries induced by alloxan.Conclusions: PR exhibited significant antihyperglycemic activity in normal and alloxan-induced diabetic mice. The results of the present study provide support to the traditional usage of the plant in diabetes

An improved magnetic field simulator - MAGFLD.

An improved two-dimensional simulator MAGFLD has been developed which is useful for the design and simulation of periodic permanent magnet (PPM) focusing system for linear beam tubes. At present, input is possible only through the input file, which is very simple and user friendly. A complete PPM circuit is generated using the coordinates of first pole piece, first magnet, gun adapter (if the structure is a-periodic) and the region of computation. Small mesh units of either square or rectangular shapes can be used with mesh refinement capability in one or more regions in any or both directions for better accuracy of the solution. Materials with different magnetic permeability can be modeled by defining a characteristic value for each mesh point of the geometry. The effective potential value at each point in the region of interest is calculated based on the vector potential model by using the 5-point finite difference method and the solution is achieved by over relaxation technique for faster convergence. This package has an interface with EGUN to model the electron gun and collector under the influence of magnetic field. Versatile color graphics are capable of plotting both axial magnetic field and flux lines along with the magnetic circuit. MAGFLD has been validated against some published data and experimental results

Substrate Current Evaluation for Lightly and Heavily Doped MOSFETs at 45 Nm Process Using Physical Models

Substrate noise is a major integration issue in mixed signal circuits; particularly at radio frequency (RF) it becomes a key issue. In deep sub micron MOSFETs hot carrier effect induces device degradation. The impact ionization phenomenon is one of the main hot carrier effects. The paper covers the process and device level simulation of MOSFETs by TCAD and the substrate current comparison in lightly and heavily doped MOS. PMOS and NMOS devices are virtually fabricated with the help of ATHENA process simulator. The modeled devices include the hot carrier effects. The MOS devices are implemented on lightly and heavily doped substrates and substrate current is evaluated and compared with the help of ATLAS device simulator. Substrate current is better in lightly doped substrate than in heavily doped one. Drain current is also better in lightly doped than heavily doped substrates. Silvaco TCAD Tool is used for Virtual fabrication and simulation. ATHENA process simulator is used for virtual fabrication and ATLAS device simulator is used for device characterization

Potentiality of Acidithiobacillus Thiooxidans in Microbial Solubilization of Phosphate Mine Tailings

This paper deals with the solubilization behavior of the tailings produced by the floatation of a complex low grade phosphate ore. The composition of the tailings was essentially dolomite (52.04%) with minor amounts of phosphate, iron and aluminium oxides (10.4 and 0.5% respectively). The presence of these products created uncontrolled land pollution and severely affected groundwater. An initiative has been taken up for utilization of this waste to generate an eco-friendly product. First step towards this panorama is incorporation of suitable microorganisms for the biodegradation of this effluent. Sulphur oxidizing bacteria Acidithiobacillus thiooxidans produces sulphuric acid which neutralizes the dolomitic tailings and convert it into plant available forms. The solubilization activity was tested in sulphur medium with 5, 10, 15 and 20% concentration of tailings. The solubilization is graded on the basis of pH, Electrical conductivity (EC), soluble calcium and magnesium and soluble phosphate. The results from ex-situ experiments showed that the treatment with 15% tailings ended with highest solubilization. The values of pH, EC, soluble calcium and magnesium and soluble phosphate for this treatment were 4.92, 31.6 dS/m, 10.8 mL EDTA and 17.24 µg/mL respectively. Also, the results proved that sulphur oxidizing bacteria Acidithiobacillus thiooxidans is capable of solubilizing dolomitic tailings from the Jhamarkotra mines. Finally, an important factor taken into account wassolubilization of residual phosphate along with dolomite in the tailings. This combined action affects the solubilization behaviour of the residue, which was also showed successfully with the assayed laboratory studies