Biomedical subjects

V S Tripathi

Publications and source records attributed to V S Tripathi.

7 recordsLinked to original sources

PubMed2001

An organically modified silicate-based ethanol biosensor.

A novel electrocatalytic ethanol biosensor using ferrocene-encapsulated palladium (Pd)-linked organically modified sol-gel glass (ormosil) is reported. The alkoxy precursors used to prepare the new ormosil-based electrocatalytic biosensor are Pd-linked glycidoxypropyltrimethoxysilane and trimethoxysilane. Pd-glycidoxypropyltrimethoxysilane (black solution) is made by mixing aqueous solutions of palladium chloride and glycidoxypropyltrimethoxysilane. The new ormosil is made using a Pd-linked silane precursor, trimethoxysilane, an aqueous solution of ferrocene monocarboxylic acid, and HCl. Alcohol dehydrogenase (ADH) is assembled over the ferrocene-ormosil layer using polyvinyl alcohol and then protecting the immobilized enzyme layer using Millipore filter membranes (pore size 1 microm). The electrocatalytic response of immobilized ADH, soluble nicotinamide adenine dinucleotide, and Pd-linked ormosil-encapsulated ferrocene is then observed. The electrocatalytic oxidation of NADH and the subsequent ADH-catalyzed formation of NADH are monitored electrochemically. Typical results recorded after the addition of varying concentrations of ethanol are reported; however, the sensor is sensitive to other alcohol and known ADH-sensitive substrates. The stability and reproducibility of the new ethanol biosensor are reported.

Alcohol Dehydrogenase↗

PubMed1980

Study of the effect of amines on structure of coacervates formed by photochemical effect on metal ions in presence of formaldehyde.

If an aqueous mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals, and formaldehyde is exposed to sunlight, typical "Jeewanu", mixtures are observed. However, if a little solution of p-phenylene diamine, p-nitroaniline, alpha-naphthylamine or beta-naphthyl amine is added to it, a dense white precipitate is obtained. This precipitate, under a microscope at X1200 magnification, appears as large clusters of very tiny cream-coloured spherules. But if the mixture is first exposed to sunlight for four hours, when the formation of typical microstructures appears, and then the amine solution is added, the formation of the precipitate is retarded as the exposure time of amine-free mixture is enhanced, till finally the formation of spherules as precipitate is stopped. Microscopic study in twenty days of exposure of the amine-containing mixture tube shows that the number of typical microstructures decreases; they get larger in size and gradually disintegrate, while the formation of tiny sdpherules is accelerated.

1-Naphthylamine↗

PubMed1980

Detergent effect on metabolic changes in microorganisms. A review.

Detergents contain a hydrophobic hydrocarbon structure and a hydrophilic group which may be anionic, cationic, or neutral. Detergents form stable emulsions and are capable of trapping lipid-soluble materials in the interior of the hydrophobic portion of the miscelles. Application of the knowledge of detergents to the discipline of microbiology would provide interesting and accurate data for further studies.

Bacteria↗

PubMed1980

Organic acids produced by self-sustaining coacervates in presence of p-nitroaniline and p-phenylene-diamine.

Oleic and malonic acids were found in control samples while p-nitroaniline addition induced production of tricarballylic acid in eight and twelve days exposed samples. Fumaric and citric acids were found in sporadic instances. Addition of p-phenylene diamine to the mixture showed a degeneration process in organic acid production. In some cases production of fumaric acid was positive.

Aniline Compounds↗

PubMed1979

Investigation of effect of alpha-naphthylamine and beta-naphthylamine on organic acids formation of self-sustaining coacervates.

Malonic and oleic acids were found in the typical mixtures. Samples containing alpha-naphthylamine gave oleic and malic acids which disintegrated with time of exposure. Tricarballylic acid was confirmed in presence of beta-naphthyl amine, but disappeared with time. Arachidic, tartaric, and adipic acids were found, but they disappeared in eight days' exposed samples. At later stages of exposure, malonic acid was observed along with sporadic appearances of citric , succinic, and oleic acids. Rate of disintegration of these compounds was directly proportional to time of exposure to sunlight.

1-Naphthylamine↗

PubMed1979

Amino acid changes in abiogenic mixtures containing p-nitroaniline and p-phenylene diamine.

Mixtures containing diammonium hydrogen phosphate, ammonium molybdate, and minerals in presence of p-nitroaniline resulted in formation of glycine, methionine, phenylalanine, tryptophan, and tyrosine. Proline and valine were observed in a few tubes. When p-phenylene diamine was present in the mixture, glycine was absent, while isoleucine and leucine were observed in the tubes. Predominance of proline was observed in all the studies executed.

Amino Acids↗

PubMed1978

Investigation of amino acid changes in self-sustaining coacervates in presence of alpha-naphthyl amine and beta-naphthyl amine.

Pronounced variation of amino acids was exhibited. Phenylalanine and tryptophan were invariably present, except at very few exposure periods. Methionine was perceived in many studies in alpha-naphthylamine, while in the study of beta-naphthylamine it was observed at four days' exposure. alpha-Naphthylamine produced cysteine along with tyrosine, leucine, isoleucine, and norleucine, while beta-naphthylamine gave valine along with tyrosine, leucine, isoleucine, and norleucine. Complete variation from blank signifies the effect of alpha- and beta-naphthyl amine on the mixture.

1-Naphthylamine↗