On the Couette-Taylor instability in ferrohydrodynamics

A theory for the stabilizing influence of an axial external magnetic field on a magnetic colloid engaged in cylindrical Couette flow is presented. For the case of a narrow gap, analytical expressions which predict the magnetic field dependences of the critical wavelength and the critical Taylor number at the onset of cellular Taylor flow are obtained.     

Advances in electrochemical detection for study of neurodegenerative disorders

Several severe neurodegenerative disorders, including Alzheimer’s disease, Parkinson’s disease, and prion-associated transmissible spongiform encephalopathies, have been linked to dysregulation of specific proteins capable of self-assembly into deleterious fibrillar aggregates termed amyloids. A wide range of analytical techniques has been used to clarify the mechanisms of these protein-misfolding processes, in the hope of developing effective therapeutic treatment. Most of these studies have relied heavily on conventional methods of protein characterization, notably circular dichroism spectroscopy, thioflavin T fluorescence, transmission electron microscopy, and atomic force microscopy, which are particularly suitable for monitoring later-stage aggregate formation. Although electrochemical methods of protein detection have existed for some time, they have only recently gained prominence as a powerful tool for studying the early stages of protein aggregation during which the more toxic soluble amyloid species form. Electrochemical detection methods include direct detection of intrinsic redox-active amino acid residues, protein-catalyzed hydrogen evolution, use of extrinsic β-sheet binding mediators, and impedance spectroscopy. In this review, we evaluate the use of electrochemistry for study of protein aggregation related to neurodegenerative disorders.

Mitochondrial targeting of selective electron scavengers: synthesis and biological analysis of hemigramicidin-TEMPO conjugates

Synthetic hemigramicidin S-peptidyl TEMPO conjugates are effectively delivered into cells and mitochondria, where they act as electron scavengers and exert protection against apoptosis. Our delivery approach is based on the use of specific structural signaling features recognizable by cells as mitochondria targeting sequences and offers considerable therapeutic anti-apoptotic potential.     

Electrochemical oxidation of 1-chloro(bromo)-2,2,6,6-tetramethylpiperidines

Electrochemical oxidation of 1-haloamines of the 2,2,6,6-tetramethylpiperidine series results in the formation of relatively stable radical-cations, detected by the methods of cyclic voltammetry and ESR spectroscopy. The final products of electrochemical oxidation of these haloamines are stable nitroxyl radicals.     

Observation of B-->K(0)(S)pi(+)pi(-) and Evidence for B-->K(*+/-)pi(-/+)

We report on a search for charmless hadronic B decays to the three-body final states K(0)(S)h(+)pi(-), K(+)h(-)pi(0), K(0)(S)h(+)pi(0) (h(+/-) denotes a charged pion or kaon), and their charge conjugates, using 13.5 fb(-1) of integrated luminosity produced near sqrt[s]=10.6 GeV, and collected with the CLEO detector. We observe the decay B-->K0pi(+)pi(-) with a branching fraction (50(+10)(-9)(stat.)+/-7(syst.))x10(-6) and the decay B-->K(*+)(892)pi(-) with a branching fraction (16(+6)(-5)(stat.)+/-2(syst.))x10(-6).     

Results of Experiments on Modification of the Sporadic E-Layer by Powerful HF Radio Waves

We present the results of experiments on modification of the sporadic E-layer of the Earth's ionosphere by a powerful vertical beam of HF radio waves. The experiments were performed at the Sura heating facility (Radiophysical Research Institute, Nizhny Novgorod) from May 31 to June 4, 2001. The main results were obtained in May 31 from 17:30 to 20:00 MSK, when the E_s layer was fairly stable and the pump frequency was in the range where this layer was transparent. The diagnostics of the ionosphere was performed using X-mode probe waves in the frequency range f_pr=4.3-7.8 MHz. The ionosphere plasma heating was accompanied by an increase in the intensity of probe waves, reflected from the E_s layer, with frequencies close to or slightly higher than the critical frequency of the layer. Artificial fluctuations of the reflected signal appeared in the entire frequency range of sounding. We consider the dynamical characteristics of the observed phenomena and their dependence on the frequency f_pr and the parameters of the E_s layer.     

Menisci in a Diamond-Shaped Capillary

This paper presents a closed form analytical solution to the augmented Young-Laplace equation for the meniscus profile in a capillary formed between four equal-sized tangent cylinders centered on the vertices of a square. The solution is valid for a large class of disjoining pressure isotherms and contact angles.     

Spontaneous and stimulated emission of radiation from hot holes from uniaxially stressed germanium

Far-infrared radiation from hot holes in Ge under streaming conditions is investigated. Stimulated emission is observed from uniaxially compressed samples without magnetic field. The existence of inversion is due to a strain splitting of the light and heavy hole bands.