Characterization of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][Tf2N])∕TX-100∕cyclohexane ternary microemulsion: investigation of photoinduced electron transfer in this RTIL containing microemulsion

In this study we have characterized a ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl- sulfonyl)imide containing ternary nonaqueous microemulsion ([Emim][Tf(2)N]∕∕TX-100∕cyclo- hexane). The phase behavior and dynamic light scattering study show that the [Emim][Tf(2)N]∕TX-100∕cyclohexane three component system can form microemulsion with [Emim][Tf(2)N] as polar core at suitable condition. We have investigated photoinduced electron transfer (PET) using dimethyl aniline as electron donor and several Coumarin dyes as electron acceptor molecules at two different R values (R = [ionic liquid]∕[surfactant]) to observe how the dynamics of the PET rate is affected in this type of confined microenvironment compared to that of the PET dynamics in neat ionic liquid and other pure solvent media. The plot of observed k(q) values with the free energy change (ΔG(0)) for electron transfer reaction shows an apparent inversion in the observed rate as predicted by the Marcus theory.     

Analytic structure of ρ meson propagator at finite temperature

We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the π ω loop, that was ignored so far in the literature.     

Carbon Nanotubes-Based Label-Free Affinity Sensors for Environmental Monitoring

Nanostructures, such as nanowires, nanobelts, nanosprings, and nanotubes, are receiving growing interest as transducer elements of bio/chemical sensors as they provide high sensitivity, multiplexing, small size, and portability. Single-walled carbon nanotubes (SWNTs) are one such class of nanostructure materials that exhibit superior sensing behavior due to its large-surface carbon atoms that are highly responsive to surface adsorption events. Further, their compatibility with modern microfabrication technologies and facile functionalization with molecular recognition elements make them promising candidates for bio/chemical sensors applications. Here, we review recent results on nanosensors based on SWNTs modified with biological receptors such as aptamers, antibodies, and binding proteins, to develop highly sensitive, selective, rapid, and cost-effective label-free chemiresistor/field-effect transistor nanobiosensors for applications in environmental monitoring.     

Metal-based anticancer agents: targeting androgen-dependent and androgen-independent prostate and COX-positive pancreatic cancer cells by phenanthrenequinone semicarbazone and its metal complexes

A planar, polycyclic and aromatic hydrocarbon ligand, namely 9,10-phenanthrenequinone semicarbazone, and its transition metal complexes have been synthesized and structurally characterized. The in vitro antiproliferative activity of these compounds against five human cancer cell lines revealed that they were effective against androgen receptor-positive/negative prostate cancer cells as well as COX-positive pancreatic BxPC-3 cancer cell line. The driving force behind such antiproliferative activity seems to be the up-regulated COX expression in these cells, which was amenable for targeting through metal complexation. These structural motifs can, therefore, serve as a starting point for developing novel cytotoxic agents against the growing number of prostate and pancreatic cancers.     

Amino-acid-dependent shift in tRNA synthetase editing mechanisms

Many aminoacyl-tRNA synthetases prevent mistranslation by relying upon proofreading activities at multiple stages of the aminoacylation reaction. In leucyl-tRNA synthetase (LeuRS), editing activities that precede or are subsequent to tRNA charging have been identified. Although both are operational, either the pre- or post-transfer editing activity can predominate. Yeast cytoplasmic LeuRS (ycLeuRS) misactivates structurally similar noncognate amino acids including isoleucine and methionine. We show that ycLeuRS has a robust post-transfer editing activity that efficiently clears tRNA(Leu) mischarged with isoleucine. In comparison, the enzyme's post-transfer hydrolytic activity against tRNA(Leu) mischarged with methionine is weak. Rather, methionyl-adenylate is cleared robustly via an enzyme-mediated pre-transfer editing activity. We hypothesize that, similar to E. coli LeuRS, ycLeuRS has coexisting functional pre- and post-transfer editing activities. In the case of ycLeuRS, a shift between the two editing pathways is triggered by the identity of the noncognate amino acid.     

Oleic acid-assisted phase transfer of nanosized silver colloids

In this study, it is demonstrated that silver nanoparticles can be transferred from formamide to chloroform using oleic acid as a phase transfer agent with a transfer efficiency of 90–95%. The silver nanoparticles are initially formed as an organosol by the reduction of silver ions with formamide. On aging the complex, the particles self-assemble to form an ordered close-packed two-dimensional array of silver nanocrystals when dissolved in CHCl₃. The size distribution of the colloidal silver particles after transfer in different solvents remains almost the same. On the basis of IR spectroscopy, we discuss the adsorption of oleic acid over the silver particles.     

Quantitative Characterization of Bovine Serum Albumin, α-Lactalbumin and β-Lactoglobulin in Commercial Whey Sample by RP-LC

A simple, sensitive and precise reverse phase liquid chromatographic method has been developed and validated for quantification of bovine serum albumin (BSA), α-lactalbumin (α-La) and β–lactoglobulin (β-Lg) that are removed from whey waste by foam fractionation method. The data is reproducible over a wide concentration range. This optimized method allowed analysis of BSA, α-La, β-Lg in a mixture within 5 min and could be applied to the analysis of a variety of commercial and laboratory whey products within a short time.     

X-ray structure of physiological copper(II)-bis(L-histidinato) complex

The isolation and the X-ray crystal structure of physiological copper(II)-L-histidine complex are reported. The neutral five-coordinate complex shows distorted square pyramidal geometry with bidentate and tridentate L-histidine ligands. The basic character of the pendent imidazole group and H-bonding interactions of bidentate L-histidine ligand are important for copper transport. The unique structural features help explain the origin of its thermodynamic stability and kinetic reactivity in human blood along with the ternary copper(II)-amino acid complexes. The role of L-histidine in interaction with copper(II)-albumin, in cellular uptake of copper, and in treatment of Menkes disease can be studied using these results.