Total synthesis of 8-methoxygoniodiol related compounds via chiron approach

The stereoselective synthesis of 8-methoxygoniodiol related compounds was accomplished by using readily available δ-gluconolactone as a chiral source. The stereoselective addition of an aryl Grignard reagent on an aldehyde, stereoselective reduction of a keto group and regioselective opening of a chiral epoxide by ethyl propiolate are the key steps involved in this synthesis.     

Debye-Waller factor of lead nitrate

The X-ray Debye-Waller factors and Debye temperatures of lead nitrate single crystals taken in the powder form have been determined by measuring integrated intensities of selected Bragg reflections at different temperatures. The characteristic specific Debye temperature has been compared with the value obtained from elastic constant data.     

Elastic constants of single crystals of the three phases of In---Pb alloys

In a study of the elastic behaviour of the InPb alloys, the elastic stiffness tensor components of crystals of each of the three phases (fct, $\text{c}\text{a}\text{> 1}$; fct, $\text{c}\text{a}\text{> 1}$; fcc) have been obtained as a function of temperature from pulse superposition measurements of ultrasonic wave velocities. Comparison of the elastic stiffness constants obtained for a fct ($\text{c}\text{a}\text{> 1}$) 5 atm.% Pb alloy with those of In itself and those of InTl and InCd alloys, establishes for this phase that alloying with Pb, as with TI and Cd, enhances the softening of the acoustic [110] phonon mode, polarization [1$\text{1}$0] near the Brillouin zone centre. The elastic properties of a 17 atm.% Pb crystal, which is in the fct ($\text{c}\text{a}\text{> 1}$) phase, are quite different from those shown by In alloys in the fct ($\text{c}\text{a}\text{> 1}$ phase; in particular the response to a shear stress is remarkably isotropie: there is no phonon mode softening in this alloy. Neither is there softening of this mode (which corresponds at the zone centre to the shear stiffness $\text{1}\text{2}$(C₁₁;C₁₂)) in crystals of the fee phase — in complete contrast to the dominating influence of the softening of $\text{1}\text{2}$(C₁₁;C₁₂) in the InTl and InCd fee alloys. In fact for a fcc In-75 atm.% Pb alloy the anistropy ratio for shear $\text{2C}{}_{44}\text{(C}{}_{11}\text{C}{}_{12}\text{)}$ is close to unity. The transitions between the three phases of the InPb alloys are markedly first order and acoustic mode softening has a much smaller influence on the elastic behaviour of the fct ($\text{c}\text{a}\text{< 1}$) and fcc InPb alloys than it has on the fct ($\text{c}\text{a}\text{< 1}$) InPb, InCd and InTl alloys.     

Phase stabilization in cinnarizine complexes using X-ray profile analysis

Characterization of cobalt(II), cadmium(II), copper(II) and tin(II) cinnarizine complexes have been carried out using conductivity, electronic spectra, infrared, nmr, thermogravimetric and X-ray analyses to establish the nature of phase stabilization in these materials. Also, the intrinsic strain components present in these materials during the formation have been computed using wide-angle X-ray scattering analysis. The variation of the crystallite shape ellipsoid in these materials has been discussed on the basis of Hosemann’s paracrystalline model.     

Characterization,Analysis, and Application of Fabricated Fe3O4-Chitosan-Pectinase Nanobiocatalyst

The investigation on fabrication of Fe₃O₄-chitosan-pectinase nanobiocatalyst was performed by covalently binding the pectinase onto carboxyl group activated chitosan-coated magnetic nanoparticles (CMNPs). The morphological and size distribution analysis of the different magnetic nanoparticles (MNPs) was done using transmission electron microscopy (TEM), and the average diameter was 11.07?±?3.04, 11.55?±?3.16, and 11.59?±?3.16 nm for MNPs, CMNPs, and fabricated nanobiocatalyst, respectively, suggesting that there was no significant change in the size of MNPs after coating and binding. The characteristic peaks occurred at 2θ of 30.39, 35.43, 43.37, 57.22, and 62.9, and their corresponding indices 220, 311, 400, 520, and 441 for different MNPs from the X-ray diffraction (XRD) studies confirmed the presence of Fe₃O₄ with the spinel structure, and there was no phase change even after coating and binding. The various required characteristic absorption peaks (575, 585, 1,563, 1,614, 1,651, and 1,653 cm^?1) from Fourier transform infrared (FT-IR) spectroscopy confirmed the surface modifications and binding of pectinase onto the MNPs. At the weight ratio of about 19.8?×?10^?3 mg bound pectinase/mg activated CMNPs, the activity of fabricated nanobiocatalyst was found to be maximum. In order to monitor their improved activity, the pH, temperature, reusability, storage ability, and kinetic studies were established.     

Comparative Quantification of the Phenolic Compounds,Piperine Content,and Total Polyphenols along with the Antioxidant Activities in the Piper trichostachyon and P. nigrum

India is the largest producer in the world of black pepper and it is the center of origin for Piper. The present study gives a comparative account of the chemical composition of the Piper nigrum and its wild putative parent the P. trichostachyon. Microextractions were performed and the quantification of six phenolic compounds (namely epicatechin, gallic acid, catechol, chlorogenic acid, caffeic acid, and catechin), piperine from leaves, petioles, and the fruits of both the species, were accomplished using the RP-UFLC system. The polyphenols (phenolic, flavonoid) and their antioxidant activities were also estimated. Among the six phenolic compounds studied, only three were detected and quantified. The polyphenol content correlating to the antioxidant activities was higher in the P. trichostachyon, whereas the piperine content was 108 times greater in the P. nigrum fruits. The Piper trichostachyon comparatively showed a higher content of polyphenols. The microextractions reduced the solvent consumption, the quantity of the plant material, and the amount of time used for the extraction. The first report on the TPC, TF, and the antioxidant activity of the P. trichostachyon has been described, and it also forms a scientific basis for its use in traditional medicine. The petioles of both species are good sources of phenolic compounds. A quantitative chemical analysis is a useful index in the identification and comparison of the species.     

Polarized Raman scattering in single crystals of Nd0.7Sr0.3MnO3

We report polarized Raman scattering in single crystals of Nd_0.7Sr_0.3MnO₃. The temperature dependence of the MnO₆ octahedral bending and stretching modes observed in the XX spectra points to the existence of local lattice distortions, possibly polarons. The XY spectra have been analyzed using a collision-dominated model, which allows the extraction of the carrier scattering rate.