Differential Effects of Cold Exposure on Gene Expression Profiles in White Versus Brown Adipose Tissue

The thermogenic function of brown adipose tissue (BAT) is known to be markedly elevated when animals are exposed to the cold, and intensive studies have been carried out to understand the molecular basis enabling effective thermogenesis in cold-exposed animals. In this study, we used microarray analysis to examine the effects of cold exposure of animals on their gene expression profiles in white adipose tissue (WAT), which seems to function as a counterpart tissue of BAT. The results indicate that the effects of cold exposure on the gene expression profiles of WAT were much more moderate than the effects on those of BAT. Possible reasons for the different responses of BAT and WAT to cold exposure are discussed.     

A new leishmanicidal saponin from Brunfelsia grandiflora

A new furostan-type saponin (1) was isolated from the methanolic extract of Brunfelsia grandiflora leaves, together with four known compounds. The chemical structure of 1 was determined by spectroscopic analysis and chemical reaction to be 26-O-beta-D-glucopyranosyl 22alpha-methoxyfurost-3beta,26-diol 3-O-beta-D-xylopyranosyl(1-->3)-{beta-D-glucopyranosyl(1-->2)}-beta-D-glucopyranosyl(1-->4)-beta-D-glucopyranoside. Compound 1 showed potent leishmanicidal activity in vitro against Leishmania major.     

Sequential protocol for C(sp3)-H carboxylation with CO2: transition-metal-catalyzed benzylic C-H silylation and fluoride-mediated carboxylation

One of the most challenging transformations in current organic chemistry is the catalytic carboxylation of a C(sp(3))-H bond using CO(2) gas, an inexpensive and ubiquitous C1 source. A sequential protocol for C(sp(3))-H carboxylation by employing a nitrogen-directed, metal-assisted, C-H activation/catalytic silylation reaction in conjunction with fluoride-mediated carboxylation with CO(2) was established. The carboxylation proceeded only at the benzylic C(sp(3))-Si bond, not at the aromatic C(sp(2))-Si, which is advantageous for further manipulations of the products.     

Optimization of Parameters for Cr(VI) Adsorption on Used Black Tea Leaves

Dynamic characteristics of Cr(VI) sorption on used black tea leaves (UBTLs) as a low-cost adsorbent are studied. Batch experiments were conducted to evaluate the effects of Cr(VI) concentration, solution pH and temperature on the removal process. Both of adsorption and reduction, involved in the process, are affected by the processing parameters. The adsorption kinetics is described successfully using pseudo-second order rate equation and the rate constant decreases with increasing the initial concentration of Cr(VI) up to 150 mg/L (for 0.1 g/L UBTLs) then becomes slow. Experimental and calculated kinetic data for equilibrium are well expressed by Langmuir isotherm. The solution pH has a profound effect on the adsorption rate. The rate constant increases linearly with an increase in temperature, and the low value of activation energy of adsorption, 16.3 kJ/mol, indicates that Cr(VI) is easily adsorbed on UBTLs. The maximum Cr(VI) adsorptive conditions, with a minimum reduction, were achieved from the dynamics of operational parameters: the initial Cr(VI) concentration < 150 mg/L (for 0.1 g/L UBTLs); the initial solution pH = 1.54–2.00 and the processing temperature < 50 ^∘C, for the possibility of its practical application.     

Efficient Simmons–Smith cyclopropanation with Zn/Cu and CH2I2

An appropriate solvent to perform the original Simmons–Smith reaction was reinvestigated. Among available solvents, cyclopentyl methyl ether (CPME), a recently commercialized ethereal solvent, was found to be the best so far. Compared with Et₂O under reflux – the commonest conditions – reaction completion in CPME at 50 °C was about 10 times faster. The product yields and selectivities were mostly identical to those with Et₂O, but were better in some cases; e.g. 13–56% with 2‐cyclohexenol. The good performance of CPME should be mainly due to its moderate polarity and high boiling point. Copyright © 2012 John Wiley & Sons, Ltd.     

O- and N-Glycosidation of d-glycals using Ferrier rearrangement under Mitsunobu reaction conditions. Application to N-nucleoside synthesis

We have disclosed the reaction of 3-hydroxy free glycals with O- or N-nucleophiles under Mitsunobu reaction conditions proceeded to produce 2,3-unsaturated glycosides in good to high yield and moderate stereoselectivity. The reaction would take place via allyloxycarbenium ion.     

Effect of electromagnetic environment effect on coherent and incoherent Cooper pair tunneling in superconducting C-SET

Cooper pair tunneling in voltage-biased superconducting C-SET structure is discussed with emphasis on the electromagnetic environment effect based on the self-consistent microscopic theory of Coulomb blockade in C-SET. It is shown that coherent Cooper pair tunneling survives only in the low impedance limit where charge fluctuation is large, while incoherent Cooper pair tunneling survives in both low- and high-impedance limits.     

Rapid speciation analysis of Cr(VI) and Cr(III) by reversed-phase high-performance liquid chromatography with UV detection

A simple and rapid method is developed for the simultaneous determination of Cr(VI) and Cr(III) based on the formation of their different complexes with ammonium pyrrolidine-dithiocarbamate (APDC). Separation is performed using reversed-phase high-performance liquid chromatography coupled with UV detection. The conditions for complex formation and speciation are determined, such as solution pH, amount of APDC, temperature, and type of mobile phase. In order to substantially reduce the analysis time, the separation is carried out without extraction of chromium-APDC complexes from the mother liquor. Under the optimum analysis conditions, the chromatograms obtained show good peak separation, and the absolute detection limits (3s) are 2.2 microg/L for Cr(VI) and 4.5 microg/L for Cr(III). The calibration curves are linear from 3 to 5000 microg/L for Cr(VI) and 5 to 3000 microg/L for Cr(III). The relative standard deviations of peak areas in five measurements using a sample solution of 200 microg/L are less than 2% for Cr(VI) and 4% for Cr(III), indicating good reproducibility for this analytical method. Furthermore, simultaneous determination of Cr(VI) and Cr(III) is successful with the application of the proposed procedure in the synthetic wastewaters containing common heavy metal ions: Fe(III), Pb(II), Cd(II), Cu(II), and Zn(II).