[en] Dielectric loss studies have been made in rubidium chloride crystals doped with Co²⁺ impurities. In this case the impurity ion consists of d-electrons in its outermost shell and is much smaller than the host cation. The peaks in the frequency isotherms follow an Arrhenius type relation. The values of activation energy for the I-V dipole and the pre-exponential factor have been determined and compared with the corresponding values in other related systems. The Co²⁺ impurities are envisaged to have occupied interstitial sites in the lattice and a new vacancy relaxation model is proposed

[en] EPR of Mn²⁺ has been studied in cadmium ammonium selenate hexahydrate host and the spin-Hamiltonian parameters determined. These results have been compared with those obtained earlier for Mn²⁺ in isomorphous paramagnetic cobalt ammonium selenate hexahydrate host. (author)

[en] Electrical conductivity has been studied in the KCl:CdCl₂ system in different heating-cooling cycles and with two different electrode materials. After the first and second heating a decrease in conductivity was found which was attributed to the effect of the silver paint used as electrodes

[en] Environmental xenobiotics are usually classified into persistent and biodegradable ones. However, this may not be universally true, since biochemical capacity of ecosystems species may vary with species diversity and versatility. This may differ in different locations decided by geoclimatic factors. Prolonged exposure of organisms causing primary degradation to the toxic xenobiotics may lead to metabolic adaptation to survive the chemical stress. Also under multiple toxicant stress, the normal biodegrading capacity may be impaired by the effect of one toxicant on the organisms per se or on the enzymes causing degradation. If such inhibition of biodegradation occurs in ecosystems, even normally biodegradable chemicals may tend to accumulate. To test this view, model experiments were conducted with LAS (Linear alkyl benzene sulphonate) a biodegradable surfactant and mercuric chloride. Since the purpose of the study was to test the degradation under natural conditions, no attempt was made to identify the micro-organisms involved

No abstract available

[en] Ecological changes caused by the continued pollution of the aquatic environment by chemicals through industrial effluents and domestic sewage and emanations settling into water pose grave concern. Synthetic detergents are one of the most important in this respect since they find their way into aquatic ecosystems thereby affecting the food chain. Earlier studies with diverse aquatic fauna and flora suggested the potential ecotoxicological impact of synthetic detergents. A large number of reports are available on the pollutants toxic to fish. Fish are known to accumulate mercury by virtue of efficient uptake and slow rate of elimination. Mercury also causes morphological and physiological defects with consequent behavioral abnormalities in fish. Even though in actual situations the stress to the ecosystem is caused by a mixture of pollutants, the interactive effect of two or more pollutants present together is poorly understood. Also, in the presence of one toxicant, the capacity of the ecosystem to deal with others can be impaired so that even biodegradable water pollutants may tend to accumulate. Therefore, an attempt has been made to study the uptake and distribution of mercury in presence and absence of detergent to test for any combined effects

[en] An attempt has been made to study the biochemical properties of lung alkaline phosphatase so that it may serve as a model for measuring the toxicity of air pollutants, especially metals. Lung was shown to be a better source of this enzyme in comparison to other organs in rats. The optimum pH, metal requirements, substrate specificity, and affinity constants were characterized with different substrates, and the effect of different metals was studied. The involvement of zinc in the lung enzyme was not indicated as shown by Sephadex G-200 elution profile of postmitochondrial supernatant of ⁶⁵Zn-treated animals

[en] Indium phosphide (InP) samples were irradiated with swift (100 MeV) ⁵⁶Fe⁷⁺ ions with different fluences varying from 5 x 10¹² to 2 x 10¹⁴ cm^-2 at room temperature. Atomic force microscopy (AFM) and high resolution X-ray diffraction (HRXRD) have been used to investigate the irradiation effects. AFM observations revealed the presence of nanosized defect clusters in all irradiated InP samples. Size (diameter) and density of defect clusters was found as a function of ion fluence. Root mean square (r.m.s) surface roughnesses measured using the Nanoscope software supplied with the AFM instrument were found to change from 0.33 nm to 7.49 nm. HRXRD studies revealed the presence of radiation-damaged layer (strained peak) in high fluence (2 x 10¹⁴ cm^-2) Fe ion irradiated InP. The screw dislocations, out of plane strain and lattice mismatch of irradiated samples have been studied