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Showing papers by "University of Madras published in 1995"


Journal ArticleDOI
TL;DR: In this paper, the photocatalysed oxidation of phenol, 2-chlorophenol and pentachlorophenol was re-examined under conditions in which TiO2 anatase was sensitized by CdS in air-equilibrated aqueous media; this was to assess whether or not the interparticle electron transfer pathway, first discovered a decade ago, could also be applied to photo-oxidative processes.
Abstract: The photocatalysed oxidation of phenol, 2-chlorophenol and pentachlorophenol was re-examined under conditions in which TiO2 anatase was sensitized by CdS in air-equilibrated aqueous media; this was to assess whether or not the interparticle electron transfer pathway, first discovered a decade ago (N. Serpone, E. Borgarello and M. Gratzel, J. Chem. Soc., Chem. Commun., (1984) 342) and subsequently applied to enhance reductive processes on titania, could also be applied to photo-oxidative processes. The results indicate that combinations such as CdS/TiO2 lead to an enhanced rate of disappearance of the initial substrate by a factor greater than two, consistent with the notion that (irradiated) CdS electrons are vectorially displaced onto the non-illuminated TiO2 particulates. Cadmium sulphide is a poorer photo-oxidation catalyst than titania. Other semiconductor materials have also been examined under a variety of conditions of pH and irradiation wavelength. The data also show that when both semiconductors in a coupled system are illuminated simultaneously and their valence and conduction bands are suitably disposed, both electron and hole transfer occur (as in the CdS/TiO2, ZnO/TiO2, TiO2/Fe2O3 and ZnO/Fe2O3 couples), which will influence the efficiency of photo-oxidation. N2O-saturated aqueous dispersions of TiO2 have no effect on the photo-oxidation of phenol, although it was expected that nitrous oxide would scavenge the photogenerated electrons in a manner similar to chemisorbed molecular oxygen, and enhance the efficiency. It is suggested that the role of oxygen in photo- oxidations may be more than just a simple electron scavenger.

641 citations


Journal ArticleDOI
TL;DR: Ca(2+)-ATPase of rat brain homogenate was protected to nearly 50% of the initial activity from the lipid peroxidant induced inactivation by this protein, which was found to be associated with the prevention of loss of -SH groups.

174 citations


Journal ArticleDOI
TL;DR: These extracts were found to be non-cytotoxic and effective antibacterial agents and studied against dysentery causing Shigella spp.

124 citations


Journal ArticleDOI
R. N. Viswanath1, S. Ramasamy1, R. Ramamoorthy1, P. Jayavel1, T. Nagarajan1 
TL;DR: In this article, the average crystallite size was estimated from the M?D profile width, using Schemer equation, and the crystallite sizes remained in nm scale on heat treatment upto 750°C.

87 citations


Journal ArticleDOI
TL;DR: Eugenol appears to act as an in vivo antioxidant and as a better inducer of phase II enzymes than phase I enzymes thanphase I enzymes, and it is suggested that eugenol could be an interesting basic structure for drug design.

83 citations


Journal ArticleDOI
TL;DR: In this article, a new quaternary superionic conducting glass with different compositions of the dopant salt AgI was prepared by rapid melt quenching, and the frequency dependence of electrical conductivity, σ, complex permittivity and electrical modulus, M ∗, were studied.

78 citations


Journal ArticleDOI
TL;DR: The finding that glutathione ester co-administration along with cisplatin is more effective and advantageous in protecting against the nephrotoxicity of cis platin when it was given alone is found.
Abstract: The objective of this study was to assess the therapeutic advantage of glutathione ester along with cisplatin. Comparisons were made with renal reduced glutathione, enzymatic antioxidants, and lipid peroxidation levels. Cisplatin caused differential toxic effects on renal antioxidants and lipid peroxidation. However administration of glutathione ester modulates the toxic effects of cisplatin observed in renal antioxidants and lipid peroxidation. The finding that glutathione ester co-administration along with cisplatin is more effective and advantageous in protecting against the nephrotoxicity of cisplatin when it was given alone.

74 citations


Journal ArticleDOI
TL;DR: Antioxidant defences are lowered in NIDDM, followed by significant rise in lipid peroxidation products, but in the erythrocyte membrane, the total polyunsaturated peroxidisable lipids are lower than in normal ERYthrocytes which may be a causative factor affecting the survival of the cells.

65 citations


Journal ArticleDOI
TL;DR: In this article, the authors extended the Painleve singularity structure analysis of two coupled systems to three coupled systems and identified four integrable sets of parameters, bilinearizing these cases to obtain soliton solutions.
Abstract: Multimode propagation of electromagnetic waves in optical fibre is often described by coupled nonlinear Schrodinger (NLS) equations. To understand the integrability properties of such coupled NLS systems, we extend the Painleve singularity structure analysis of two coupled systems to three coupled systems and identify four integrable sets of parameters. We bilinearize these cases to obtain soliton solutions. The results are extended to N-coupled systems, completing the earlier analysis of Sahadevan, Tamizhmani and Lakshmanan.

60 citations


Journal ArticleDOI
TL;DR: The present results suggest that prepubertal hypothyroidism suppresses both basal and stimulated Leydig cell activity in adult rats.
Abstract: Leydig cell steroidogenic activity under basal and stimulated conditions was studied in hypothyroid rats. Hypothyroidism was induced at a prepubertal age (30 days postpartum) by surgical thyroidectomy, and L-thyroxine (T4) supplementation (6 micrograms/100 g body weight/day for 30 days) to hypothyroid rats was begun after 30 days. Hypothyroidism for 60 days reduced serum LH and FSH without affecting prolactin. Serum and intratesticular testosterone and the specific activity of Leydig cell 3 beta- and 17 beta-hydroxysteroid dehydrogenases diminished in hypothyroid rats. The stimulatory effect of LH on Leydig cell steroidogenic activity and cAMP was also adversely affected in hypothyroid rats. All these changes were reversed by T4 supplementation. The present results suggest that prepubertal hypothyroidism suppresses both basal and stimulated Leydig cell activity in adult rats.

59 citations



Journal ArticleDOI
TL;DR: This report demonstrates the power of homozygosity mapping to identify disease loci in small nuclear families by identifying a locus for recessive NSHL on 14q (DFNB4).
Abstract: Hearing impairment is inherited most frequently as an autosomal recessive isolated clinical finding (non-syndromic hearing loss, NSHL). Extreme heterogeneity and phenotypic variability in the audiometric profile preclude pooling of affected families and severely hamper gene mapping by conventional linkage analysis. However, in instances of consanguinity, homozygosity mapping can be used to identify disease loci in small nuclear families. This report demonstrates the power of this technique by identifying a locus for recessive NSHL on 14q (DFNB4).

Journal ArticleDOI
TL;DR: Lupeol administration (25 mg/kg body weight/day) reduced significantly the renal excretion of oxalate and reduced the extent of renal tubular damage as evidenced from the decreased levels of the above enzymes in urine.
Abstract: Investigations were undertaken to study the role of lupeol, a pentacyclic triterpene from Crataeva nurvala stem bark, in calcium oxalate experimental rat urolithiasis. A 2% solution of ammonium oxalate was administered by gastric intubation for inducing hyperoxaluric condition in adult male rats of Wistar strain. The duration of treatment was for 15 days. This resulted in increased urinary excretion of oxalate associated with reduction in citrate and glycosaminoglycans. The urinary marker enzymes which indicate renal tissue damage namely--lactate dehydrogenase, inorganic pyrophosphatase, alkaline phosphatase, gamma glutamyl transferase, beta-glucuronidase and N-acetyl beta-D glucosaminidase were found to be elevated. Lupeol administration (25 mg/kg body weight/day) reduced significantly the renal excretion of oxalate. It also reduced the extent of renal tubular damage as evidenced from the decreased levels of the above enzymes in urine. Such a reduction is likely to be beneficial in minimizing the deposition of stone-forming constituents in the kidney which provides antilithic effect.

Journal ArticleDOI
TL;DR: In this article, the visible light-induced hydrogen production by water splitting reactions was studied by using undoped or Rh(III) Cu(II) -doped, with or without RuO2 loaded α-Fe2O3 at different pH values in the presence of methyl viologen (MV2+) as an electron relay.

Journal ArticleDOI
TL;DR: In this paper, buthionine sulfoximine (BSO), an irreversible inhibitor of gamma-glutamylcysteine synthetase, produces glutathione (GSH) depletion in tumors, making them sensitive to drugs and radiation.

Journal ArticleDOI
TL;DR: Cysteine administration to glycollate-fed rats brought about a significant decrease in the peroxidative level, with an increase in the antioxidant status, and an increased xanthine oxidase and decreased glucose-6-phosphate dehydrogenase activity.

Journal ArticleDOI
TL;DR: Monodon baculovirus exists in populations of the Indian tiger prawn, Penaeus monodon, obtained from a commercial hatchery in Madras, India and the mortality rate in infected populations of P. monodon was 90%.

Journal ArticleDOI
TL;DR: It is suggested that a sex-related difference seems to occur in the stimulation of spontaneous motor activity, liver injury and mortality that result from repeated exposure to sublethal doses of endosulfan in rats.

Journal ArticleDOI
TL;DR: Thirty days after induction of experimental diabetes the brain catecholamines namely, norepinephrine (NE) and epinephrine (E) were studied in discrete brain regions in control, alloxan-diabetic untreated and insulin-treated diabetic rats.

Journal ArticleDOI
TL;DR: The crystal structures of the first two non-self-complementary hexadeoxyribonucleotide duplexes with Watson-Crick base pairs are solved and the differences in the structure under similar environmental conditions point to a sequence-dependent plasticity in the DNA molecule which is visible even under close-packed conditions.

Journal ArticleDOI
TL;DR: All size groups showed progressive reduction in physiological activities such as filtration rate, foot activity and byssus thread production when chlorine residuals were increased from 0 to 1.5 ppm.
Abstract: Results of a study on lethal and sublethal responses of green mussel, Perna viridis exposed to different levels of chlorine, are presented. At 1 ppm chlorine residuals, 12 mm size group mussels showed 100% mortality in 504 hours (21 days) and 95 mm size group mussels in 816 hours (33 days). At relatively high levels of chlorine residuals (10 ppm), 100% mortality in 12 mm and 95 mm size groups took 30 and 48 hours, respectively. All size groups showed progressive reduction in physiological activities such as filtration rate, foot activity and byssus thread production when chlorine residuals were increased from 0 to 1.5 ppm. Reduction in physiological activities of mussels was strongly correlated with the concentration of chlorine.

Book ChapterDOI
TL;DR: The temporal distribution patterns of the predominantly occurring postlarvae and juvenile shrimps in the mangrove and associated habitats of Muthupet, India were investigated for two years and P. monodon clearly showed the preference to the detritus rich muddy substrate, whereas P. dobsoni did not show any preference and was equally abundant over different substrate types.
Abstract: The temporal distribution patterns of the predominantly occurring postlarvae and juvenile shrimps in the mangrove and associated habitats of Muthupet, India were investigated for two years from February 1984 to January 1986 Among the eight commercially important species recorded, Penaeus indicus H Milne Edwards, P merguiensis De Man, P monodon Fabricus and Metapenaeus dobsoni (Miers) were predominant The postlarval recruitment size varied with species: P indicus and P merguiensis recruited at the size of 9–11 mm total length (TL), P monodon at 12–14 mm TL and M dobsoni at 4–6 mm TL The species P indicus, P merguiensis and M dobsoni were observed continuously throughout the study period with maximum abundance occurring from July to September in 1984–85 and from August through October in 1985–86 P monodon occurred seasonally from November to January in both years Postlarvae and juvenile catches were low during low salinity and high salinity periods and a higher density was observed in the months of moderate water salinity Large numbers of P indicus, P merguiensis and M dobsoni clearly showed the preference to the detritus rich muddy substrate, whereas P monodon did not show any preference and was equally abundant over different substrate types

Journal ArticleDOI
TL;DR: In this article, a pit-induced fatigue failure of a stainless steel total hip prosthesis was found to be the cause of failure of the implant, and the study contributed to the understanding of the failure mechanisms of metal fixtures under the action of biomechanical forces.
Abstract: Metals are often chosen as implant materials because of their inherent mechanical properties. Currently the surgical implants are usually made of one of the following three materials: austenitic stainless steels, cobalt-chromium alloys, and titanium and its alloys [1]. Among all of these materials austenitic stainless steels, especially type 316L stainless steels, are widely used because of their relatively low costs and reasonable corrosion resistance [2]. All implant devices are exposed to living cells, tissues and biological fluids which are dynamic and also hostile in nature. Moreover, the design of an implant is dictated by the anatomy and physiology of the skeletal structure of the human body. The artificial mechanical devices are considered to have failed when they are prematurely removed from the body as the implant does not accomplish its intended function, and hence has to be removed due to the implant corrosion and/or fracture. In every failure of an orthopaedic implant the patient is made to experience the trauma of repeated surgery besides severe pain experienced during the process of rejection of the device. The removal of the implant may cause great expense and hardship to the patient. Therefore, it is highly desirable to keep the number of failures to a minimum. Hence, the determination of the mechanism that caused failure of an implant is important, but it is also necessary to explore the event or sequence of events which caused that particular mechanism to become operative. Furthermore, failure investigation will help to improve the total performance of implant devices, besides revealing the details of the mode and origin of the failure mechanism. In spite of the recent innovative metallurgical and technological advances and remarkable progress in the design of implants, failures of implants do occur [3]. Although failures of implants have been reported to be due to fatigue [4, 5], corrosion [6, 7] and/or other general failure mechanisms [8, 9], the underlying causes for the initiation of these failure mechanisms are seldom determined. The causes of failures may also be due to biomechanical reasons rather than to faults in the basic design and/or metallurgy of the implant. The diagnostic study described in this letter reveals that the failure of the implant is typically a pit-induced fatigue failure of a stainless steel total hip prosthesis, and the study contributes to the understanding of the failure mechanisms of metal fixtures under the action of biomechanical forces.

Journal ArticleDOI
TL;DR: Data is presented on the lethal and sublethal effects of temperature on the green mussel Perna viridis, a species causing fouling problems for the Madras Atomic Power Station, located on the east coast of India.
Abstract: Biofouling in the cooling water circuits of coastal power stations presents considerable problems for their normal operation. Although chlorination is commonly practised, operational problems, safety concerns and environmental issues have made it necessary to look for alternative methods of control. Heat treatment is considered as a viable alternative and is being practised by a few utilities in the USA and The Netherlands. This paper presents data on the lethal and sublethal effects of temperature on the green mussel Perna viridis, a species causing fouling problems for the Madras Atomic Power Station, located on the east coast of India. The mortality pattern and the physiological behaviour (byssus thread production, filtration rate and foot activity index) of the green mussel were studied at temperatures varying from 10°C to 46°C. Synergistic effects of salinity and temperature on mortality were also studied. Exposure of 2 mm size group mussels to a temperature of 39°C showed 50% mortality in 58 min and...

Journal ArticleDOI
TL;DR: In this article, a three-step synthesis of novel multi-site water soluble phase transfer catalyst, α,α′-bis(triethyl ammonium methylene chloride) β-phenyl ethene, is described.

Journal ArticleDOI
TL;DR: The histomorphology and ultrastructure of the vas deferens is reported on with reference to its functional role in secreting the sperm bearing materials.
Abstract: Unlike the other penaeiodean shrimp, the ridge back shrimp, Sicyoniaingentis does not produce a spermatophore, but transfers sperm suspended in seminal plasm. This paper reports on the histomorphology and ultrastructure of the vas deferens with reference to its functional role in secreting the sperm bearing materials. The vas deferens is divisible into proximal secretory, mid storage and distal ejaculatory regions. The epithelial cells lining the proximal vas deferens are comprised of secretory and absorptive cell types. The loose sperm cells found in the lumen of this region are in an immature condition, and are agglutinated into a compact mass with signs of spermiogenesis in the mid vas deferens. The epithelial cells lining the mid vas deferens are short flattened cells. The distal vas deferens is ensheathed by muscular fibres. The inner epithelial cells are highly secretory and contain numerous microvilli at the luminal end. The sperm cord gets liquefied in this region facilitating the transfer of sperm in liquid form to the female during mating.

Journal ArticleDOI
TL;DR: The combination therapy showed greater efficacy in the treatment of fibrosarcoma than did individual administration, as there was more reduction in the levels of enzymes in Group V than those in to Groups III and IV.
Abstract: Cyclophosphamide, and antineoplastic drug, and vitamin E, the common antioxidant present in the diet, were administered in separate dosages and in combination to animals (rats) with fibrosarcoma, metastatic tumor of the connective tissues, induced. The anticancer drug (20 mg/kg body weight) and the vitamin-E (400 mg/kg body weight) was administered for a period of 28 days from the day of tumor transplantation. The individual and the combined effects of these two substances were investigated by checking the growth of the tumor. Tumor markers like lactate dehydrogenase (LDH), serum glutamate pyruvate transminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), acid phosphatase, and alkaline phosphatase were analyzed for the changes in their concentration in serum, liver, and kidney to assess the success of the therapy. The increased level of the enzymes in the fibrosarcoma-suffering rats (GPII) was reduced by cyclophosphamide treatment (GP III) and vitamin E administration (GP IV). Among the treated groups, the combination therapy (GP V) showed greater efficacy in the treatment of fibrosarcoma than did individual administration, as there was more reduction in the levels of enzymes in Group V than those in to Groups III and IV. The enzyme levels were brought to near the normal level.

Journal ArticleDOI
TL;DR: In this paper, the Ticinella roberti Zone and Whiteinella archaeocretacea Zone were recognized for the first time in the Cauvery Basin and several subzones and assemblage zones were elevated to zonal status.

Journal ArticleDOI
TL;DR: This study suggests that heat treatment is an attractive alternative to chlorination for mussel fouling control in tropical power stations.

Journal ArticleDOI
TL;DR: The reduced level of γ-crystallin transcripts is the first alteration observable during the embryonic development of the Cat2 mutant lenses; it precedes the morphological changes.
Abstract: • Background: From previous experiments it is known that the murine dominant cataract mutants carrying the gene Cat2 have a decreased content of γ-crystallin-specific transcripts in the juvenile lenses, when the cataract is completely expressed. Moreover, the mutant locus has been mapped recently to chromosome 1, closely linked to the γE-crystallin gene (map distance 0.3±0.3 cM). In the present paper we describe the phenotypic changes and the γ-crystallin expression in embryonic lenses of the Cat2 nop mutants as an example for the Cat2 allelic series. •. Methods: The technique of in situ hybridization was applied using a probe from the murine γD-crystallin gene, and, for control, from the murine αA-crystallin gene. Simultaneously, a series of lens sections was examined histologically. • Results: The presence of γ-crystallin mRNA was demonstrated from embryonic day 13.5 (E13.5) onward, but in the mutants to a lower extent than in the wild-type lenses. However, the first morphological abnormality in the mutant lenses was observed as swelling of lens fibers at day E15.5. Progressive degeneration of the lens core followed, leading to a cataracta immatura. • Conclusion: The reduced level of γ-crystallin transcripts is the first alteration observable during the embryonic development of the Cat2 mutant lenses; it precedes the morphological changes. This result represents an additional line of argument that the γ-crystallin genes may be the target of the mutation in the Cat2 mice.