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- Author or Editor: Rajendra Prasad x
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Uranium content of soil samples collected from different states of India, namely Uttar Prades, Rajasthan and Kerala has been estimated. The areas cover the normal background area, high background area and dumpyards of fertilizer factory and thermal power plant. Plastic sheets were used as a detector for the registration of fission tracks resulting from the (n, f) reaction on235U present in the sample due to the thermal neutrons from a nuclear reactor. The uranium concentration has been found to vary from 0.24 to 9.20 μg/g in various soil samples. Higher levels of uranium were found in the vicinity of a coal fired power plant. The present results may be useful for the radiation hygiene.
Water samples collected from various sources along the south-west coastal region of India have been analyzed for trace uranium concentration. Fission track registration technique with the Dry method has been used for the analysis. Uranium concentration was found to vary from 0.28±0.01 g/l to 2.71±0.41 g/l and was higher in sea water than in well, river and tap water, respectively.
Pathogenic yeasts from the genus Candida can cause serious infection in humans particularly, in immunocompromised patients and are now recognized as major agents of hospital acquired (nosocomial) infections. In the recent years, there has been a marked increase in the incidence of treatment failures in candidiasis patients receiving long-term antifungal therapy, which has posed a serious problem in its successful use in chemotherapy. Candida cells acquire drug resistance (MDR) during the course of the treatment. The mechanisms of resistance to azole antifungal agents have been elucidated in Candida species and can be mainly categorized as (i) changes in the cell wall or plasma membrane, which lead to impaired drug (azole) uptake; (ii) alterations in the affinity of the drug target Erg11p (lanosterol 14∝-demethylase) especially to azoles or in the cellular content of Erg11p due to target site mutation or overexpression of the ERG11 gene; and (iii) the efflux of drugs mediated by membrane transport proteins belonging to the ATP-binding cassette (ABC) transporters, namely CDR1 and CDR2 or to the major facilitator superfamily (MFS) transporter, CaMDR1 . Many such manifestations are associated with the formation of Candida biofilms including those occurring on devices like indwelling intravascular catheters. Biofilm-associated Candida show uniform resistance to a wide spectrum of antifungal drugs. A combination of different resistance mechanisms is responsible for drug resistance in clinical isolates of Candida species.
A hot vacuum extraction technique for the determination of hydrogen in metal and alloy samples has been standardised. After measuring the total pressure of the evolved gases, individual hydrogen and deuterium intensities are measured using an on-line quadrupole mass spectrometer. Synthetic mixtures of H2 and D2, in known concentrations, have been analysed by QMS and an analytical expression correlating the measured [D2]/[HD] intensity ratio with the mole fraction of deuterium in the synthetic mixture has been arrived at. The precision and accuracy in the measurement of hydrogen is about 10% at 50 ppmw level.