Analysis of Electrical Discharge Machining

Technical Physics - Breakdown in liquid dielectric medium, plasma channel, and heat transfer in the course of electrical discharge machining are studied. Specific features and most important...     

Assessment by the Fluorescence Imaging Methods of the Antitumor Efficacy and Apoptotic Activity of Biologically Active Additives Containing Resveratrol,Indole-3-Carbinol,and Cordycepin in Human Renal Carcinoma Cells

Optics and Spectroscopy - The efficacy of antitumor efficacy and apoptosis induction in A498 human renal cell carcinoma observed when applying extracts of cruciferous herbal material...     

Enantioselective Ir(I)-catalyzed carbocyclization of 1,6-enynes by the chiral counterion strategy

Enantioenriched bicyclo[4.1.0]hept-2-enes were synthesized by Ir(I)-catalyzed carbocyclization of 1,6-enynes. No chiral ligands were used, CO and PPh(3) were the only ligands bound to iridium. Instead, the stereochemical information was localized on the counterion of the catalyst, generated in situ by reaction of Vaska's complex (trans-[IrCl(CO)(PPh(3))(2)]) with a chiral silver phosphate. Enantiomeric excesses up to 93% were obtained when this catalytic mixture was used. (31)P NMR and IR spectroscopy suggest that formation of the trans- [Ir(CO)(PPh(3))(2)](+) moiety occurs by chlorine abstraction. Moreover, density functional theory calculations support a 6-endo-dig cyclization promoted by this cationic moiety. The chiral phosphate anion (O-P*) controls the enantioselectivity through formation of a loose ion pair with the metal center and establishes a C-H···O-P* hydrogen bond with the substrate. This is a rare example of asymmetric counterion-directed transition-metal catalysis and represents the first application of such a strategy to a C-C bond-forming reaction.     

Generation of Droplet Quasi-Bessel Beams Using a Semiconductor Laser

Optics and Spectroscopy - A method for generation of droplet quasi-Bessel beams using a conical lens with a rounded tip is demonstrated. The study of the longitudinal distribution of the intensity...     

An EPR study of the radical addition to 3‐nitropentan‐2‐one as an archetype of α‐carbonylnitroalkanes

Carbon, silicon, germanium, tin and lead‐centered radicals were reacted with 3‐nitropentan‐2‐one and 3‐nitropentan‐2‐ol inside the cavity of an electron paramagnetic resonance spectrometer. In all cases, selective addition to the nitrogroup was observed with detection of the corresponding oxynitroxide radicals. In the case of the carbonyl substrate, alkyl acyl nitroxides were also detected because of α‐photocleavage. The oxynitroxides decayed with a first order kinetics via fragmentation of the carbon–nitrogen bond (denitration). Unexpectedly, the activation parameters were fairly similar to those previously reported for the corresponding tert‐butyl oxynitroxides and almost independent from the presence of a carbonyl or a hydroxyl group on the carbon adjacent to the one bearing the nitrogroup. Copyright © 2014 John Wiley & Sons, Ltd.     

Targeted molecular dynamics of an open-state KcsA channel

Pore opening of KcsA channel is studied using targeted molecular dynamics simulations. Conformational changes of the protein are determined, starting from the crystallized refined 2.0 A structure (pdb 1K4C) determined in x-ray experiments and arriving to the open-state structure constructed on the basis of electron paramagnetic resonance spectroscopic data (pdb 1JQ1). Our results corroborate the essential role played by the terminal residues located on the transmembrane helices M2 which were not taken into account at that time. The aperture mechanism of the channel appears to be ziplike. A small constraint (approximately equal to 5 x 10(-2) kcal mol(-1) A(-2) per C(alpha)) applied to the terminal residues located on the intracellular side is sufficient to initialize the pore opening at the innermost part of the gate, but additional constraint must be applied to definitely complete the pore aperture. The open structure is proved to be a metastable state since releasing the constraint leads to another relaxed open conformation which seems to reach stability.     

Minimal involution-free nongroup reduced twisted subsets

A subset K of a group G is said to be twisted if 1 ∈ K and the element xy ^?1 x lies in K for any x, y ∈ K. We study finite involution-free twisted subsets that are not subgroups but all of whose proper twisted subsets are subgroups. We also study the groups generated by such twisted subsets.     

Advantages and Possibilities of Fluorescence-Based Methods for the Visualization of Apoptosis and Autophagy in Human Tumor Cells in vitro

Optics and Spectroscopy - The possibilities of using fluorescence-based analytical methods and their advantages for visualization and identification of the type of programmed cell death in human...     

Free transport-entropy inequalities for non-convex potentials and application to concentration for random matrices

Talagrand’s inequalities provide a link between two fundamentals concepts of probability: transportation and entropy. The study of the counterpart of these inequalities in the context of free probability has been initiated by Biane and Voiculescu and later extended by Hiai, Petz and Ueda for convex potentials. In this work, we prove a free analogue of a result of Bobkov and Götze in the classical setting, thus providing free transport-entropy inequalities for a very natural class of measures appearing in random matrix theory. These inequalities are weaker than the ones of Hiai, Petz and Ueda but still hold beyond the convex case. We then use this result to get a concentration estimate for $\beta $ -ensembles under mild assumptions on the potential.     

Experimental investigation of the electrocaloric response in ferroelectric materials

We have analyzed the electrocaloric response in ferroelectric materials in nonequilibrium thermal conditions. The temperature dependences of the electrocaloric response during polarization and depolarization of ferroelectric samples based on solid solutions of barium–strontium titanate and lead magnoniobate–titanate are considered. The difference in the electrocaloric responses for polarization and depolarization, which can be as large as 5 mK, has been demonstrated experimentally.