Reflection and transmission of plane waves at the interface of an elastic half-space and a fractional order thermoelastic half-space

The problem of reflection and transmission due to longitudinal and transverse waves incident obliquely at a plane interface between uniform elastic solid half-space and fractional order thermoelastic solid half-space has been studied. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence and frequency of incident wave and are influenced by the fractional order thermoelastic properties of media. The expressions of amplitude ratios and energy ratios have been computed numerically for a particular model. The variation of amplitude and energy ratios with angle of incidence is shown graphically. The conservation of energy at the interface is verified.     

Intruder configurations in the A=33 isobars: 33Mg and 33Al

The beta decay of 33Mg (N=21) presented in this Letter reveals intruder configurations in both the parent and the daughter nucleus. The lowest excited states in the N=20 daughter nucleus, 33Al, are found to have nearly 2p-2h intruder configuration, thus extending the "island of inversion" beyond Mg. The allowed direct beta-decay branch to the 5/2{+} ground state of the daughter nucleus 33Al implies positive parity for the ground state of the parent 33Mg, contrary to an earlier suggestion of negative parity from a g-factor measurement. An admixture of 1p-1h and 3p-3h configurations is proposed for the ground state of 33Mg to explain all of the experimental observables.     

Structures of the BrF(4)(+) and IF(4)(+) cations

The large discrepancies between the calculated and observed structures for BrF(4)(+) and IF(4)(+) (Christe, K. O.; Zhang, X.; Sheehy, J. A.; Bau, R. J. Am. Chem. Soc. 2001, 123, 6338) prompted a redetermination of the crystal structures of BrF(4)(+)Sb(2)F(11)(-) (monoclinic, P2(1)/c, a = 5.2289(6) A, b = 14.510(2) A, c = 14.194(2) A, beta = 90.280(1) degrees, Z = 4) and IF(4)(+)SbF(6)(-) (orthorhombic, Ibca, a = 8.2702(9) A, b = 8.3115(9) A, c = 20.607(2) A, Z = 8). It is shown that for BrF(4)(+), the large differences were mainly due to large errors in the original experimental data. For IF(4)(+)SbF(6)(-), the geometry previously reported for IF(4)(+) was reasonably close to that found in this study despite a very large R-factor of 0.15 and a refinement in an incorrect space group. The general agreement between the calculated and the redetermined geometries of BrF(4)(+) and IF(4)(+) is excellent, except for the preferential compression of one bond angle in each ion due to the influence of interionic fluorine bridges. In BrF(4)(+), the fluorine bridges are equatorial and compress this angle. In IF(4)(+), the nature of the fluorine bridges depends on the counterion, and either the axial (in IF(4)(+)SbF(6)(-)) or the equatorial (in IF(4)(+)Sb(2)F(11)(-)) bond angle is preferentially compressed. Therefore, the geometries of the free ions are best described by the theoretical calculations.     

Purification and Characterization of the Enzyme Cholesterol Oxidase from a New Isolate of Streptomyces sp.

An extracellular cholesterol oxidase (cho) enzyme was isolated from the Streptomyces parvus, a new source and purified 18-fold by ion exchange and gel filtration chromatography. Specific activity of the purified enzyme was found to be 20 U/mg with a 55 kDa molecular mass. The enzyme was stable at pH 7.2 and 50 °C. The enzyme activity was inhibited in the presence of Pb(2+), Ag(2+), Hg(2+), and Zn(2+) and enhanced in the presence of Mn(2+). The enzyme activity was inhibited by the thiol-reducing reagents (DTT, β-mercaptoethanol), suggesting that disulfide linkage is essential for the enzyme activity. The enzyme activity was found to be maximum in the presence of Triton X-100 and X-114 detergents whereas sodium dodecyl sulfate fully inactivated the enzyme. The enzyme showed moderate stability towards all organic solvents except acetone, benzene, chloroform and the activity increased in the presence of isopropanol and ethanol. The K(m) value for the oxidation of cholesterol by this enzyme was 0.02 mM.     

Ratiometric sensing of Hg2+ based on the calix[4]arene of partial cone conformation possessing a dansyl moiety

A new fluorescent chemosensor based on the calix[4]arene of partial cone conformation possessing a dansyl moiety has been synthesized. The chemosensor demonstrates selective optical recognition of Hg(2+) and Cu(2+) in two contrasting modes. The receptor exhibited ratiometric sensing of Hg(2+) and "ON-OFF" type of fluorescence behavior in the presence of Cu(2+). The compound behaves as a fluorescent molecular switch upon chemical inputs of Hg(2+) and Cu(2+) ions.     

Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-beta-lactam

We report herein the synthesis and biological evaluation of bile acid dimers linked through 1,2,3-triazole and bis-beta-lactam. The dimers were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-beta-lactams , and terminal alkynes derived from cholic acid/deoxycholic acid in the presence of Cu(i) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7 cells were also established.     

Pyrazine Based Type-I Sensitizing Assemblies for Photoreduction of Cu(II) in ‘One-Pot Three-Component’ CuAAC Reaction Under Aerial Conditions

Photosensitizing assemblies of pyrazine derivative PDA have been developed which exhibit a high photostability, ‘lighted’ excited state, balanced redox potential, high transportation potential and activate oxygen via type-I pathway only. These PDA assemblies in combination with Cu(II) ions catalyze the CuAAC reaction via in situ reduction of Cu(II) ions without any reducing or stabilizing agent. The present protocol has wide substrate scope with recyclability of the catalytic system up to six catalytic cycles and is applicable to gram-scale synthesis.     

Ratiometric nanomolar detection of Cu(2+) ions in mixed aqueous media: a Cu(2+)/Li(+) ions switchable allosteric system based on thiacalix[4]crown

A novel ditopic fluorescent chemosensor 2, based on the 1,3-alternate conformation of thiacalix[4]crown possessing two complexation sites, was synthesized and shows ratiometric nanomolar detection of Cu(2+) ions and exhibits negative allosteric behaviour between Cu(2+)/Li(+) ions in mixed aqueous media.     

A pentaquinone-based 4-2 bit photonic encoder

A new pentaquinone-based chemosensor armed with phenolic moieties has been synthesized. The fluorescence behaviour of the chemosensor in the presence of different chemical inputs mimics the functions of a digital encoder.