Optimization of the chiral resolution of baclofen by capillary electrophoresis using beta-cyclodextrin as the chiral selector

The chiral resolution of baclofen was achieved by capillary electrophoresis using a fused-silica capillary (60 cm x 75 microm ID). The background electrolyte (BGE) was phosphate buffer (pH 7.0, 50 mM)-acetonitrile (95:5 v/v) containing 10 mM beta-cyclodextrin. The applied voltage was 15 kV. The values of alpha and R(s) were 1.06 and 1.00, respectively. The electrophoretic conditions were optimized varying the pH and the ionic strength of the BGE, concentrations of beta-cyclodextrin and acetonitrile and the applied voltage.     

An efficient method for synthesis of phenacyl derivatives under homogeneous phase transfer catalyst condition in aqueous media

In this letter,a mild and efficient procedure for synthesis of phenacyl derivatives under homogenous catalysis in the presence of tetrabutylammonium bromide in aqueous media is described.The nucleophilic substitution reactions were performed under ecofriendly conditions and gave the corresponding products in high yields and short reaction times.     

Phytoconstituents from the rhizomes of Curcuma aromatica Salisb.

Phytochemical investigation of the chloroform extract of the rhizomes of Curcuma aromatica Salisb. (Zingiberaceae) yielded three new phytoconstituents characterized as n-heneitriacontan-14-one; n-pentatriacontan-5-one; 11α-cyclopentyl-n-decan-1-ol (curcumapentadecanol) along with the known compounds stigmasterol and n-nonacosan-1-ol. The structures of these phytoconstituents have been elucidated on the basis of structural data analysis and chemical reactions.     

A Convenient Synthesis of 6,8-Dimethoxy-3-[（2-（4-methoxyphenyl）ethyl）isocoumarin

6,8-Dimethoxy-3-[2-（4-methoxyphenyl）ethyl]isocoumarin was synthesized by condensation of 5,7-dimethoxyhompophthalic acid with 3-（4-methoxyphenyl）propanoyl chloride. The structure of the synthesized compound was confirmed by its mass spectrometric studies. The synthesized compound serves as a model for synthesis of DL-agrimonolide.     

Electron microscopic studies of the antiferroelectric phase in Sr0.60Ca0.40TiO3 ceramic

The structural variants and their coexistence across the antiferroelectric phase transition in Sr_0.60Ca_0.40TiO₃ ceramic has been studied through transmission electron microscopy (TEM) at room temperature and ∼100 °C. A clear evidence of the presence of superlattice reflections, corresponding to the cell doubling along the c-axis of Pbnm (or b-axis along Pnma), occurring during paraelectric to antiferroelectric transition, has been obtained through selected area electron diffraction, convergent beam electron diffraction and lattice-resolution imaging. Coexistence of the Pbnm and Pbcm phases at room temperature has been observed and attributed to the strain/disorder-induced broadening of the first-order antiferroelectric phase transition. Drastic changes in the domain structure during Pbnm to Pbcm transformation have been observed. This clearly indicates that the antiferrodistortive transition responsible for the occurrence of the antiferroelectric phase is of completely different origin and it is not just an additional follow-up of the already-existing ordering due to a⁻a⁻c⁺ tilt schemes in the Pbnm domain. Thermal cycling studies on microstructural changes indicate some kind of memory mechanism, which retains the memory of the original a⁻a⁻c⁺ tilt schemes in the Pbnm phase. This has been attributed to the symmetry conforming short-range order (SC-SRO) of the point defects.     

Two-point method for T1 estimation with optimized gradient-echo sequence

Relaxation times estimation methods play a central role in various problems, such as magnetic resonance (MR) hardware calibration, tissue characterization, or temperature measurement. Previous studies have proposed optimization criteria to estimate the relaxation time T1 faster than with a multipoint method leading to two-point methods. In this paper, the class of optimized two-point methods is extended to gradient-echo (GE) sequence offering new advantages over spin-echo (SE) or inversion recovery (IR) sequences. Two GE acquisitions, with optimal flip angles theta1 and theta2 minimizing both the total scan time and the variance in the computed T1 image were applied to estimate T1, and the results were compared with those of SE sequence with optimized paired repetition times T(R1) and T(R2). First, phantom studies were carried out with five tissue-like samples on a 0.5T scanner. Then in vivo, human brain T1 image were calculated using both optimized GE and SE two-point methods. More precise T1 GE estimates than those for SE were found thanks to high signal-to-noise ratio (SNR) per unit of time, but with a small bias. These results also concern the temperature variation measurement methods, based on T1 estimation. Preliminary experimental data for temperature measurement are given.     

Excitation functions of 93Nb(p,x) reactions from threshold to 42.5 MeV

Journal of Radioanalytical and Nuclear Chemistry - The excitation functions of 93Nb(p,x) reactions from their respective thresholds to 42.5 MeV were measured at the MC-50 cyclotron of...     

Minireview: Silver-Doped Titanium Dioxide and Silver-Doped Zinc Oxide Photocatalysts

The catalytic oxidation of organic dyes using various systems has been widely reported during the past decade. Photocatalytic methods, heterogeneous processes for the degradation of dyes, are one of the best and efficient oxidation processes to treat industrial wastewater with minimal residual waste. This review describes the improvement in catalytic activity of silver-doped titanium dioxide and silver-doped zinc oxide. The degradation of dyes provides information about the catalytic performance of silver-doped metal oxide. The effects of pH, catalyst concentration, dye concentration, hydrogen peroxide, dissolved oxygen, temperature, irradiation time, and light source have been reviewed along with the degradation mechanism and reaction methodology of organic dyes.