Showing papers by "Jawaharlal Nehru University published in 1974"
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01 Jan 197443 citations
TL;DR: In this paper, the absorption and fluorescence spectra of chlorophyll-a and chlorophyLL-b solutions in a concentration of 6 · 10−6 M were determined in 22 solvents in order to determine the positions and molar extinction coefficients of the red absorption band, the positions of the fluorescence bands, the oscillator strengths of red bands and the Stokes' shifts.
Abstract: The absorption and fluorescence spectra of chlorophyll-a and chlorophyll-b solutions in a concentration of 6 · 10−6 M were determined in 22 solvents. The positions and the molar extinction coefficients of the red absorption band, the positions of the fluorescence bands, the oscillator strengths of the red bands and the Stokes’ shifts are tabulated. The results can be summarized as follows:
The changes in the oscillator strength and the Stokes’ shifts obey roughly the theory of “internal field effect”. An evaluation of this effect yields 0.34 and 0.50 for the ratios of the polarizability of the chlorophylls and the Onsager radius of the solvents, for chlorophyll-a and chlorophyll-b, respectively. The results indicate that chlorophyll-b is more sensitive to environmental effects than chlorophyll-a.
36 citations
TL;DR: Oxygen-free hydration affords maximal protection against the post-irradiation oxygen-dependent (Class III) damage assessed as M 1 seedling injury, chromosomal aberrations and M 2 chlorophyll mutations.
Abstract: Oxygen-free hydration affords maximal protection against the post-irradiation oxygen-dependent (Class III) damage assessed as M 1 seedling injury, chromosomal aberrations and M 2 chlorophyll mutations. Heat shock and caffeine also eliminate part of this damage. When heat shock and caffeine are successively applied, the level of protection afforded by anoxic hydration is significantly reduced. Caffeine applied during anoxic hydratjion reduces the seedling injury to a much great extent than it reduces the frequency of chlorophyll mutations. The role of heat shock, under these conditions, is almost to reverse the ratio of seedling injury to chlorophyll mutations. The probable mechanism of action of caffeine as well as the implications of differential modification of the seedling injury and genetic damage are briefly discussed.
27 citations
TL;DR: Experiments with RNA- and protein-synthesis inhibitors indicate that the appearance of new enzyme activity is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.
Abstract: The presence of N-acetylglucosamine is essential for the induced synthesis of N-acetylglucosamine kinase in Candida albicans. The enzyme synthesis stops and its concentration in the cells declines rapidly as soon as N-acetylglucosamine is removed from the medium. Experiments with RNA- and protein-synthesis inhibitors indicate that the appearance of new enzyme activity is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.
20 citations
TL;DR: Cycloheximide, an inhibitor of protein synthesis completely prevents induction of N-acetylglucosamine kinase, and by blocking the RNA synthesis by actinomycin D or by suppressing the transport of nuclear mRNA to cytoplasm by cordycepin, no further synthesis of the kinase is observed.
18 citations
TL;DR: La cystéine est un radio-protecteur plus efficace que la caféine contre le dommage post-irradiatoire dû à l'oxygène, but c'est seulement the caféine qui détermine l'amplitude and le genre de modification.
Abstract: La cysteine est un radio-protecteur plus efficace que la cafeine contre le dommage post-irradiatoire du a l'oxygene. Mais la cysteine n'exerce aucune influence sur la partie du dommage qui ne depend pas de l'oxygene et la cafeine accentue ce dommage. Dans le traitement simultane de cafeine et de cysteine, c'est seulement la cafeine qui determine l'amplitude et le genre de modification.
12 citations
01 Jan 1974
TL;DR: In this paper, the authors discuss the stability in an economy with production, and present a framework within which the stability of competitive equilibrium is demonstrated in an exchange economy, so that production decisions have no role to play.
Abstract: Publisher Summary This chapter discusses the stability in an economy with production. The usual framework within which the stability of competitive equilibrium is demonstrated is that of an exchange economy, so that production decisions have no role to play. The most important result in stability analysis has been the recognition of the fact that in a gross substitute economy, global stability prevails. The most general form of the adjustment process in such a framework has been the one employed by McKenzie. The difficulty with this condition lies in the regrettable but unavoidable fact that if production conditions are normal, some factor inputs are complementary to one another. The chapter reviews the results that are available for application to a production economy. Any condition for stability that allows for complementarity would be such a result.
6 citations
TL;DR: Un traitement de caféine avant and de cystéine après l'irradiation offre le maximum de protection.
Abstract: Tandis que l'emploi de cafeine avant l'irradiation tend a augmenter le dommage fait aux chromosomes, l'application de cysteine immediatement apres l'irradiation diminue ce dommage. Par consequent, un traitement de cafeine avant et de cysteine apres l'irradiation offre le maximum de protection.
6 citations