• S N Singh

      Articles written in Journal of Biosciences

    • Reduction in population growth under different contraceptive policies

      S N Singh K N S Yadava

      More Details Abstract Fulltext PDF

      A number of equations for the various population control policies are worked out for a desired reduction in the rate of growth. At the ages of 25 and 30 respectively, 61 and 97% of contraceptive users are necessary to reduce the present rate of growth of 0.026 to 0.010. While at the age of 25 about 69 and 76% contraceptive users are required for the same reduction in the rate of growth, assuming that 25 and 50% would discontinue the use of contraceptives at the age of 35. The birth and death rates in the study area (Varanasi Rural) have remained almost constant for several years, justifying the assumption of a stable population. This study emphasises the need for the use of contraceptive devices at two or more age levels.

    • Regulation of rat liver NADP+-isocitrate dehydrogenase during aging

      R N Singh Yadav S N Singh

      More Details Abstract Fulltext PDF

      In an attempt to understand the mechanism of aging in relation to the differences in enzyme regulation, the induction and kinetic properties of NADP+ -isocitrate dehydrogenase of the liver of immature (6 weeks), mature (13 weeks), adult (33 weeks) and old (85 weeks) female rats were studied. The specific activity of the cytoplasmic and mitochondrial NADP+ -isocitrate dehydrogenase increased up to the adult age (33 weeks) and decreased in the old rats (85 weeks). Overiectomy decreased and estradiol administration induced activity of both the mitochondrial and eytoplasmic enzyme in the liver ol immature, mature and adult rats but had no significant effect in old rats. However, the activity of mitochondrial NADP+ -isocitrate dehydrogenase decreased and eytoplasmic NADP+ -isocitrate dehydrogenase increased following ovariectomy in old rats (85 weeks). Hormone-mediated induction of enzyme activity was actinomycin D sensitive. The Km for isocitrate and NADP, Ki value for oxalomalate, heat stability and electrophoretic mobility of the purified enzyme from the cytosol fraction of the liver of immature and old rats were similar. It can he concluded that the enzyme does not change structurally with age.

    • A probability model for the number of births in an equilibrium birth process

      S N Singh V K Singh

      More Details Abstract Fulltext PDF

      A probability model for the number of complete conceptions (that is, live births) taking into account foetal wastages, occurring in a couple during a specified period of time (T0, T0+T) is developed assuming that the data was collected starting a long time after marriage. A method of estimating some of the underlying parameters is given. The model is applied to data obtained in a Varanasi Survey in 1969–70.

  • Journal of Biosciences | News

      Forthcoming Special issue.

    • To trigger further research on plant mitochondria, the Journal of Biosciences is bringing out a special issue titled "Plant Mitochondria: Properties and Interactions with Other Organelles".

      Plant mitochondria are quite distinct and have unique features, such as a cyanide-insensitive alternate pathway. They also interact with chloroplasts to optimize photosynthetic carbon assimilation.

      Submissions are welcome until 30 July 2023. The contributions can be original articles, short communications, reviews, or mini-reviews on any topic related to plant mitochondria.

      Authors can submit their articles online at https://www.editorialmanager.com/jbsc/default2.aspx

      Posted on April 12, 2023
    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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