Correlation analysis of reactivity in the reduction of Co(en)2Br2+ by Fe(CN)64– in water–methanol/1,4-dioxane media

The reduction of [Co(en)₂Br₂]⁺ by [Fe(CN)₆]^4– in H₂O–MeOH and H₂O–1,4-dioxane mixtures has been studied over a range of solvent compositions [5–30% (v/v)]. The reduction of [Co(en)₂Br₂]⁺ was monitored under second order conditions and was found to be rapid in the various solvent compositions investigated. The favoured mechanism is an outer-sphere electron-transfer process consisting of elementary steps, ion-pair formation (K _IP), electron-transfer (k _et) and successor dissociation. Therefore, the overall rate constant, k ₂ = K _IP k _et[Co(en)₂- Br₂ ⁺][Fe(CN)₆ ^4–]. The rates increase as the proportion of organic cosolvent increases. The rates correlate with solvent properties, such as relative permittivity (_r) and the Grunwald–Winstein parameter, Y _GW, which are used to explain the non-specific interaction upon solvation of mixture of solvents on the incipient reactants and on the ion-pair. In addition, they are also subjected to multiparametric analysis employing Swain's solvent vectors A and B also with Kamlet–Taft's solvatochromic parameters , and *. The reduction rates show an excellent correlation with multiparametric equations and are susceptible to both specific and non-specific solvation effects. A quantitative estimation of the latter components has been attempted.     

Numerical analysis of characteristic features of shallow and deep cavity in supersonic flow

Flow past open cavities are numerically simulated at a Mach number of 1.5, and Reynolds number, based on initial momentum thickness at the front lip of cavity, of 3333 for variable depths (D) with constant length (L). The dominant frequency of oscillation shows a sudden jump when there is a transition from shallow (L/D > 1) to deep cavity (L/D < 1). The vorticity thickness displays two different growth rates along the length of cavity: (1) initial lower spreading rate, followed by (2) higher spreading rate. The lower spreading rate of shear layer is dictated by the type of cavity (either shallow or deep), while the higher spreading rate is directly related to the amplitude of oscillations. Proper orthogonal decomposition (POD) is implemented to visualise the coherent structures based on their energy content. The first two POD spatial structures in the shallow cavity represent vortex shedding, while in the deep cavity, they comprise vortex pairing interactions as in mixing layer. The higher POD modes contain coherent structures at mixed frequencies. The behaviour of coherent structures associated with a temporal frequency is further investigated using dynamic mode decomposition (DMD). The higher DMD modes confirm the dominance of mixing layer behaviour in the deep cavity.     

Chemical composition of the essential oil from basil (Ocimum basilicum Linn.) and its in vitro cytotoxicity against HeLa and HEp-2 human cancer cell lines and NIH 3T3 mouse embryonic fibroblasts

This study examines the chemical composition and in?vitro anticancer activity of the essential oil from Ocimum basilicum Linn. (Lamiaceae), cultivated in the Western Ghats of South India. The chemical compositions of basil fresh leaves were identified by GC-MS: 11 components were identified. The major constituents were found to be methyl cinnamate (70.1%), linalool (17.5%), β-elemene (2.6%) and camphor (1.52%). The results revealed that this plant may belong to the methyl cinnamate and linalool chemotype. A methyl thiazol tetrazolium assay was used for in?vitro cytotoxicity screening against the human cervical cancer cell line (HeLa), human laryngeal epithelial carcinoma cell line (HEp-2) and NIH 3T3 mouse embryonic fibroblasts. The IC(50) values obtained were 90.5 and 96.3?μg?mL(-1), respectively, and the results revealed that basil oil has potent cytotoxicity.