Search Results - (Author, Cooperation:M. Dubey)

2015-11-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-06-12

American Physical Society (APS)

0556-2813

1089-490X

Physics

Nuclear Reactions

1089-7550

AIP Digital Archive

Physics

Germanium films were deposited on GaAs (100) substrates with or without an epiready surface oxide at temperatures between room temperature (RT) and 500 °C using an ultrahigh-vacuum e-beam deposition system. The film at 100 °C on a substrate with a surface oxide had a flat absorption curve over the wave-number range investigated, 500–4000 cm−1, with an absorption of less than 10/cm at 1000 cm−1 (10 μm wavelength). Films deposited at RT and 50 °C on substrates with a surface oxide had comparable low absorption, but they contained an absorption peak at 830 cm−1 associated with the Ge—O bonds. Although all three films were amorphous, the films deposited at the lower temperatures were more porous. This enabled oxygen to percolate in from the atmosphere to form the Ge—O bonds. The films deposited at 150 °C and above on substrates with a surface oxide and at 100 °C with the surface oxide removed thermally in situ prior to deposition the Ge films, and the single crystal films deposited at 400 and 500 °C on oxide-free substrates, had strong absorption in the vicinity of the Ge/GaAs interface with the characteristic of two-dimensional free-carrier absorption. © 1996 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Single crystal germanium films were deposited on (100) GaAs and InGaP substrates, and highly oriented gold films were deposited on the germanium films by ultrahigh vacuum E-beam evaporation. They were characterized by double crystal x-ray diffraction (DXRD), transmission electron microscopy (TEM), Rutherford backscattering spectroscopy (RBS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). The germanium film grew epitaxially with a smooth, abrupt interface, and the highly oriented gold film formed a smooth interface with the germanium and had a (100)Au(parallel)(100)Ge and (001)Au(parallel)[011]Ge or [001]Au(parallel)[0-1 1]Ge orientation relationship. Large grains with one or the other orientation relationship could be distinguished in the SEM. TEM micrographs show that the grains have a periodic dislocation pattern indicative of heteroepitaxy, and the grain boundaries appear to have a low energy. No contamination was detected in the gold film away from the interface with the germanium, and there was significant channeling of the RBS beam when it was normal to the gold film.

Electronic Resource

0020-1693

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

1432-0703

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Medicine

Abstract Manganese chloride was administered daily intraperitoneally to growing and adult rats for a period of 30 days to compare certain biochemical parameters in both groups of animals. Marked alterations in the levels of dopamine and norepinephrine in the brain was observed in manganese-treated growing rats. Furthermore, the contents of tyrosine, tryptophan in blood, liver, and brain have been significantly altered in these animals. Identical manganese administration to adult rats had no effect on the contents of tyrosine in liver and brain, nor tryptophan, and dopamine in the brain. Some of the parameters which were altered in the adult rats were less in magnitude compared to the growing animals. The experiments indicated higher susceptibility of the growing rats to the toxic effects of this metal.

Electronic Resource

1432-0584

Transfusion malaria ; Thalassaemia ; Antigen detection

Springer Online Journal Archives 1860-2000

Medicine

Summary A total of 125 β-thalassaemia patients receiving repeated blood transfusions were screened by Giemsa stain, Acridine-orange stain and antigen detection for evidence of malaria infection on each visit. A total of 8 (6.4%) of the patients developed post-transfusion malaria (PMT) as confirmed by tracing the infected blood donors. A high incidence of PTM in thalassaemia patients appears to be due to the use of fresh blood and the high frequency of blood transfusions required by these patients. Antigen detection using monoclonal antibody was found to be more sensitive for diagnosis of PTM and for screening suspected donors than the conventional blood smear examination methods and is therefore recommended for routine blood donor screening to rule out malaria infection.

Electronic Resource

1432-0584

Malaria ; Plasmodium falciparum ; Erythrocyte ; Lipid peroxidation

Springer Online Journal Archives 1860-2000

Medicine

Summary The extent of reduced glutathione, activity of glutathione peroxidase, amount of membrane lipid peroxidation products, and the extent of hemoglobin release from host erythrocytes during in vitroPlasmodium falciparum growth was studied. Highly synchronized parasite cultures were studied to examine the alterations caused by different growth stages of the parasite. There was a moderate increase in the reduced glutathione content as the parasite matured, which was significant only in schizontrich erythrocyte lysates (p〈0.05) whereas the activity of glutathione peroxidase was significantly low in all the parasitized red blood cells (ring-infected RBC,p〈0.005; trophozoite- and schizont-infected RBC,p〈0.001). The lipid peroxidation product, malonyldialdehyde, of the host red cells increased gradually to more than fourfold in schizont-rich cells as compared with normal erythrocytes (p〈0.001). The hemoglobin release from cultured cells was significantly higher in all parasitized red cell cultures as well as in uninfected cells kept in in vitro, as compared with normal erythrocytes. The consequence of such changes induced by the malarial parasites in the host red cells in the pathogenesis of erythrocyte destruction and anemia ofP. falciparum malaria is discussed.

Electronic Resource

1432-1912

Heart ; Noradrenaline release ; Potassium ; Calcium ; Methacholine

Springer Online Journal Archives 1860-2000

Medicine

Summary 1. Noradrenaline release from the isolated rabbit heart was evoked by perfusion with a medium containing 135 mM potassium and 17 mM sodium ions (high K+-low Na+). 2. The noradrenaline output in response to high K+-low Na+ was dose-dependently decreased by methacholine (0.625–320 μM) and this effect was reserved by atropine 1.44 μM. 3. Lowering the calcium concentration of high K+-low Na+ from 1.8–0.1125 mM decreased the noradrenaline output by 85%. The effect of methacholine, expressed as % inhibition of noradrenaline release, was potentiated by lowering of the calcium concentration. 4. Both at normal and lowered calcium concentrations the inhibitory action of methacholine was larger from 0–5 than from 5–10 min after perfusion with high K+-low Na+. 5. Perfusion of hearts with media containing high K+-high Na+ or normal K+-low Na+ caused noradrenaline outputs somewhat smaller than those after high K+-low Na+. The release from 0–5 min was both calcium-dependent and inhibited by methacholine. 6. High K+ and/or low Na+ solutions caused an increase in coronary perfusion pressure which was little affected by the noradrenaline released simultaneously. 7. It is concluded that activation of muscarine receptors at the terminal adrenergic fibre decreases the availability of calcium for transmitter release.

Electronic Resource