Browsing by Author "S. Mehta"

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An amperometric enzyme electrode for lactate based on graphite paste modified with tetracyanoquinodimethane
(1994) P.C. Pandey; V. Pandey; S. Mehta
An amperometric enzyme electrode for lactate is described. The construction of an enzyme electrode involves the incorporation of tetracyanoquinodimethane (TCNQ) and lactate dehydrogenase (LDH) into the graphite paste. The response of the electrode to lactate is based on the oxidation of NADH at 220 mV vs SCE based on a LDH catalyzed reaction through the mediated mechanism. Data are also reported on the oxidation of NADH within the TCNQ mediated graphite paste electrode without LDH as a function of binder composition. It has been found that the response of the electrode is decreased on increasing the binder ratio. This is attributed to the limited transport of NADH within the paste. Similarly, the effect of enzyme (LDH) concentration incorporated in the graphite paste vs the enzyme electrode response for NADH is also reported. An increase in enzyme concentration results in the decreased response of the electrode, again related to the limited mass-transport at the oil-solution interface. The response curve for lactate is slightly dependent on the anodic potential. The effects of interferences (pH and temperature) on the response of the enzyme sensor are also reported. It was found that the response is nearly constant within a 6·5-8·5 pH range whereas the variation of the temperature shows a biphasic curve on the response, probably attributed to the heterogeneous reaction at a lower temperature and homogeneous reaction at a higher temperature. The stability of the enzyme sensor is better, with a loss of a 45% response after 30 d on storage at room temperature in phosphate buffer (0.1 M, pH 7·5). © 1994.
Brain free amino acids glutamic acid system in growing rats fed wheat & Bengalgram protein diets
(1979) C. Prasad; S. Mehta; K.N. Agarwal
[No abstract available]
Plant growth-promoting rhizobacteria-elicited alterations in phenolic profile of chickpea (Cicer arietinum) infected by Sclerotium rolfsii
(2002) B.K. Sarma; D.P. Singh; S. Mehta; H.B. Singh; U.P. Singh
Efficacy of seven strains of Pseudomonas fluorescens (Pfs1-7), plant growth-promoting rhizobacteria (PGPR), were tested under field conditions for their ability to protect Cicer arietinum against Sclerotium rolfsii infection. Best protection was observed in strain Pfs3 where 23% seedling mortality was recorded in comparison to 44% in non-treated control. To correlate the induction of phenolic compounds by the PGPRs with disease resistance, qualitative and quantitative alterations of phenolic compounds in different parts of C. arietinum were estimated following PGPR application as seed treatment. High performance liquid chromatographic (HPLC) analysis of the leaves, collars and roots of the PGPR-treated and non-treated (control) plants showed the presence of gallic, ferulic, chlorogenic and cinnamic acids with varied amounts in the PGPR-treated as well as non-treated (control) plants. Maximum accumulation of cinnamic acid was observed in plants treated with Pfs3 strain (1660 ng g-1 fresh wt.) which was almost 19.5 times higher than untreated control plants and also significantly high when compared to other PGPR treatments. Pfs3 also caused maximum accumulation of total phenolics and gallic acid in all chickpea plant parts as compared to other treatments and untreated control. A direct relationship between the level of total phenolics and seedling survivability was observed. PGPR-mediated induction of phenolic compounds as a biochemical barrier in C. arietinum against S. rolfsii infection is envisaged.
'Upper celosomia' - report of two cases with embryological explanation
(1978) T.K. Lahiri; J. Sahni; M.N. Khanna; S. Mehta
[No abstract available]