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6-Phenylazo-3-( p -tolyl)-2 H -chromen-2-one 4 was prepared and characterized by IR, 1 H, and 13 C NMR spectral studies. The optimized structure of the chromen-2-one 4 was investigated by the Gaussian 03 B3LYP density functional method calculations at 6-31G(d,p) basis set. The gauge-independent atomic orbital (GIAO) 13 C and 1 H chemical shift calculations for the synthesized chromen-2-one in CDCl 3 were also made by the same method. The computed IR frequencies of the chromen-2-one and the corresponding vibrational assignments were analyzed by means of potential energy distribution (PED%) calculation using vibrational energy distribution analysis (VEDA) program. The first order hyperpolarizability ( β tot ), polarizability ( α ) and dipole moment ( μ ) were calculated using 6-311G(d,p) basis set and the nonlinear optical (NLO) properties are also addressed theoretically. Stability of the chromen-2-one 4 molecule has been analyzed by calculating the intramolecular charge transfer using natural bond order (NBO) analysis. The molecular electrostatic potentials, HOMO–LUMO energy gap and geometrical parameters were also computed. Topological properties of the electronic charge density in chromen-2-one 4 were analyzed employing the Bader’s Atoms in Molecule (AIM) theory which indicated the presence of intramolecular hydrogen bond in the molecule. [ABSTRACT FROM AUTHOR]

Abstract: Effects of UV-A, UV-B and their combination on spore viability and larvicidal activity of an indigenous isolate of Bacillus sphaericus Neide, ISPC-8 were studied under laboratory conditions. The UV sensitivity of ISPC-8 was compared with standard strain 1593 and larvicidal activity was tested against third instar larvae of mosquito, Culex quinquefasciatus Say. No significant adverse effects on viability as well as larvicidal activity of both strains were observed when spores were exposed to UV-A for 6h. However, exposure to UV-B for a few minutes adversely affected the spore viability as well as larvicidal activity and this adverse effect was more pronounced on spore viability. In both strains about 50% larvicidal activity was retained after exposure of the spores to UV-B for 8h. However, spore viability at this exposure of time was drastically reduced to 2.5% in ISPC-8 and 0.3% in 1593. The spore viability and larvicidal activity patterns were found to be similar to UV-B treatment when spores were exposed to a combination of UV-A and UV-B. Our study hence, shows the adverse effect of UV radiation on ISPC-8 and 1593 indicating the need to incorporate eco-friendly UV protectants in formulations so that the efficacy of biopesticides based on these entomopathogens can be prolonged under field conditions, especially in tropical countries. [Copyright &y& Elsevier]

Nitrogen dioxide (NO2) is an environmental oxidant, known to be associated with lung epithelial injury. In the present study, cellular pro-inflammatory responses following exposure to a brief high concentration of NO2 (45 ppm) were assessed, using normal human bronchial epithelial (NHBE) cells as an in vitro model of inhalation injury. Generation and release of pro-inflammatory mediators such as nitric oxide (NO), IL-8, TNF-α, IFN-γ and IL-1β were assessed at different time intervals following NO2 exposure. Effects of a pre-existing inflammatory condition was tested by treating the NHBE cells with different inflammatory cytokines such as IFN-γ, IL-8, TNF-α, IL-1β, either alone or in combination, before exposing them to NO2. Immunofluorescence studies confirmed oxidant-induced formation of 3-nitrotyrosine in the NO2-exposed cells. A marked increase in the levels of nitrite (as an index of NO) and IL-8 were observed in the NO2-exposed cells, which were further enhanced in the presence of the cytokines. Effects of various NO inhibitors combined, with immunofluorescence and Western blotting data, indicated partial contribution of the nitric oxide synthases (NOSs) toward the observed increase in nitrite levels. Furthermore, a significant increase in IL-1β and TNF-α generation was observed in the NO2-exposed cells. Although NO2 exposure alone did induce slight cytotoxicity (<12%), but presence of inflammatory cytokines such as TNF-α and IFN-γ resulted in an increased cell death (28–36%). These results suggest a synergistic role of inflammatory mediators, particularly of NO and IL-8, in NO2-mediated early cellular changes. Our results also demonstrate an increased sensitivity of the cytokine-treated NHBE cells toward NO2, which may have significant functional implications in vivo. [Copyright &y& Elsevier]