Inhibition of Carcinogen-induced Activity of γ-Glutamyl Transpeptidase by Certain Dietary Constituents in Mouse Skin

Cancer chemoprevention, a desirable and important facet of biomedical research, Provides a practical approach to identify potentially useful inhibitors of cancer development, and offers an opportunity to study the mechanism of carcinogenesis. During the recent past a nuInber of compounds have been tested for their anticarcinogenic potential specially constituents of human diet. The enzyme y-glutamyl transpeptidase (CGT), which catalyses the transfer of glutamyl gnups of peptides to other peptides and amino acids, has been proposed as a marker of cell proliferation and neoplasia. It also serves as a tool to evaluate the carcinogenic and cocareinogenic poential of environmental toxicants. In the present investigations, GGT activity induced by carcinogenic polycyclic aromatic hydrocarbons, viz. 7, 12-dimethyl-benz(a) anthracene (DMBA) and benzo(a)Pyrene (BaP was significantly inhibited by diallylsulfide (DAS) and indole-3-carbinol (13C) in mouse skin. DAS and 13C are Constituents of garlic. A significant inhibition in GGT levels was also observed in a strong mitogen (12-o-tetradecanoyl phorbol-13-acelate) induced activity by pretreatment of DAS/13C in mouse skin. Therefore these dielary constituents seem to be strong modifiers of chemically induced carcinogenesis.

Grid Tied Solar PV System with Power Quality Enhancement Using Adaptive Generalized Maximum Versoria Criterion

A three phase grid tied solar photovoltaic(PV)system with power quality compensation features is presented in this paper.This system is used to transfer power generated from a solar PV array to feed linear and nonlinear loads along with compensation for several power quality(PQ)issues,such as harmonics,redundant reactive power and load unbalancing.The generated DC power from the PV array is converted into AC by implementing a three-phase voltage source converter(VSC).In order to transfer active power and mitigate PQ problems,an efficient control technique is required for the grid tied solar PV system.This study presents the use of an adaptive generalized maximum Versoria criterion(AGMVC)controller for VSC used in a solar PV energy conversion system.Efficient utilization of the solar PV array is accomplished by using the Perturb and Observe based maximum power point tracking(MPPT)algorithm.The experimental setup of the grid integrated PV system is implemented in the laboratory using an IGBT based VSC and DSP(dSPACE DS-1202).The performance of the AGMVC control technique is verified experimentally using laboratory prototype.This control technique is compared with different conventional controllers,such as synchronous reference frame theory(SRFT)and instantaneous reactive power theory(IRPT)along with recently developed weight-based controllers viz.,least mean square(LMS),least mean mixed norm(LMMN)and normalized kernel least mean fourth-neural network(NKLMFNN).Numerous terms,such as fundamental weight convergence,steady state error,computational complexity,phase lock loop(PLL)requirement and harmonic compensation capability,are considered for comparison purposes of AGMVC with the above listed control techniques.The system performance is verified according to the IEEE-519 standard.

Microbial Biomass Dynamics in a Tropical Agroecosystem： Influence of Herbicide and Soil Amendments

The influences of herbicide alone and in combination with the soil amendments with contrasting resource qualities on dynamics of soil microbial biomass C （MBC）, N （MBN）, and P （MBP） were studied through two annual cycles in rice-wheat-summer fallow crop sequence in a tropical dryland agroecosystem. The experiment included application of herbicide （butachlor） alone or in combination with various soil amendments having equivalent amount of N in the forms of chemical fertilizer, wheat straw, Sesbania aculeata, and farm yard manure （FYM）. Soil microbial biomass showed distinct temporal variations in both crop cycles, decreased from vegetative to grain-forming stage, and then increased to maximum at crop maturity stage. Soil MBC was the highest in herbicide ＋ Sesbania aculeata treatment followed by herbicide ＋ FYM, herbicide ＋ wheat straw, herbicide ＋ chemical fertilizer, and herbicide alone treatments in decreasing order during the rice-growing period. During wheat-growing period and summer fallow, soil MBC attained maximum for herbicide ＋ wheat straw treatment whereas herbicide ＋ FYM, herbicide ＋ Sesbania, and herbicide ＋ chemical fertilizer treatments showed similar levels. The overall trend of soil MBN was similar to those of soil MBC and MBP except that soil MBN was higher in herbicide ＋ chemical fertilizer treatment over the herbicide ＋ wheat straw treatment during rice-growing period. In spite of the addition of equivalent amount of N through exogenous soil amendments in combination with the herbicide, soil microbial biomass responded differentially to the treatments. The resource quality of the amendments had more pronounced impact on the dynamics of soil microbial biomass, which may have implications for long-term sustainability of rainfed agroecosystems in dry tropics.