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Y Srivastava

Publications and source records attributed to Y Srivastava.

8 recordsLinked to original sources
PubMed2005

Quantum drag forces on a sphere moving through a rarefied gas.

As an application of quantum fluid mechanics, we consider the drag force exerted on a sphere by an ultradilute gas. Quantum mechanical diffraction scattering theory enters in that regime wherein the mean free path of a molecule in the gas is large compared with the sphere radius. The drag force is computed in a model specified by the "sticking fraction" of events in which a gaseous molecule is adsorbed by the spherical surface. Classical inelastic scattering theory is shown to be inadequate for physically reasonable sticking fraction values. The quantum mechanical scattering drag force is exhibited theoretically and compared with experimental data.

Journal Article↗
PubMed2004

Adult 175 kDa collagenase antigen of Setaria cervi in immunoprophylaxis against Brugia malayi in jirds.

A 175 kDa antigen fraction with collagenase activity was isolated and purified from somatic extracts of adult Setaria cervi females using column chromatography involving consecutive steps of DEAE-Sepharose CL6B and Sephadex G-100. The optimum pH for 175 kDa collagenase was found to be pH 7.0. Sensitivities to a variety of inhibitors and activators indicated that the 175 kDa coIlagenolytic enzyme was metalloserine in nature. The enzyme hydrolysed a variety of protein substrates such as haemoglobin, casein, azocasein (general substrates) and collagen, FALGPA (furanoyl-acryloyl-leu-gly-pro-ala), the specific substrate of collagenase. The enzyme showed 57% inhibition by jird anti-somatic collagenase antibodies and reacted insignificantly with normal jird sera. Further analysis was undertaken on the immunoprophylactic potential of 175 kDa collagenase in inducing immunity against Brugia malayi (a human filarial parasite) in jirds (Meriones unguiculatus) in vitro and in situ. Immune sera of jirds raised against this antigen promoted partial adherence of peritoneal exudate cells to B. malayi microfilariae (mf) and infective larvae (L3) in vitro and induced partial cytotoxicity to the parasites within 48 h. The anti-S. cervi 175 kDa antigen serum was more effective in inducing cytotoxicity to B. malayi L3, than mf. In the microchambers implanted inside immune jirds, host cells could migrate and adhere to the mf and infective larvae thereby killing them partially within 48 h.

Animals↗
PubMed1988

Effect of Momordica charantia Linn. pomous aqueous extract on cataractogenesis in murrin alloxan diabetics.

The fruit extract of Momordica charantia Linn. was studied in Charles Foster rats of both sexes in respect of its dose-response hypoglycemia and at maximal effective dose, its influence on the development of diabetic cataract. Alloxan (120 mg/kg s.c./rat, single dose) diabetic rats with greater than 150 mg% of blood sugar were classified into four groups (n = 10) wherein two were control and the rest were test groups). In the test group, the oral dose response hypoglycemic herbal effect was found to be maximum at 4 g/kg/Day/rat when administered for 20 days. This dose was continued in the 2nd test group for a period of 2 months. Blood sugar in all the rats was estimated by microdetermination method using a dextrometer before and after therapy. The control group of rats received 2 ml of 0.9% NaCl and they developed cataract in 90 to 100 days. The herbal treated diabetics showed cataract in 140 to 180 days. Cataract formation was found to be dependant on blood sugar levels since the control group with blood sugar 307 +/- 81 (mg%) was blind 2 months earlier than herbal treated group which showed blood sugar 149 +/- 66.37 (mg%).

Animals↗
PubMed1983

Glucose tolerance in patients with cerebrovascular accidents and their blood relatives.

The present study was undertaken to examine whether there is any hereditary correlation, with reference to the abnormal glucose metabolism, between patients with cerebrovascular accidents and their healthy blood relatives in respect to the occurrence of cerebrovascular disease. The investigation was carried out by intravenous glucose tolerance test (IV-GTT) and prednisolone-primed glucose tolerance test (PP-GTT) in 83 subjects. Of these, 20 were healthy (control) persons (group A), matched in age and sex with 50 patients with cerebrovascular accidents (group B) and 13 family relatives of group B (group C) showing unequivocal GTT or PP-GTT. In controls, the IV-GTT criterion, i.e. k value, was found generally to be 2.82 +/- 0.43 and in persons less than 50 and over 50 years old, it was found to be related with age, i.e. 3.1 +/- 0.73 and 2.53 +/- 0.43, respectively. The 21 patients of group B with normal GTT response had a k value of 2.53 +/- 1.88 and the 29 patients with abnormal GTT response had a k value of 1.2 +/- 0.33. Among the 21 patients of group B, 11 had normal IV-GTT and their PP-GTT was found to be 125 +/- 12.5 mg%. The other 10 patients with abnormal IV-GTT exhibited a PP-GTT of 173.4 +/- 26.43 mg%. In 14 and 15 patients, the time-lapse difference of 7 and 8-21 days after stroke showed an abnormal GTT response and in 6 and 15 patients it showed a normal response. Among 13 healthy relatives of group B (group C), only 1 subject was found to have abnormal IV-GTT (k value of 1.386) and 2 were found to have abnormal PP-GTT (182.8 and 388.0 mg%), thus indicating pre-symptomatic diabetics.

Cerebrovascular Disorders↗