Long-lived free induction decay signal in CsMnF<inf>3</inf> single crystal

Elementary excitations in antiferromagnets are magnons, and these quasiparticles with integer spin are governed by Bose statistics. In certain conditions their density can be controlled by applied radiofrequency pulse leading to the formation of Bose-Einstein condensation (BEC). We report the investigations of free induction decay signal duration in CsMnF3 under different conditions and discuss it in the framework of the magnon BEC. The observed results in CsMnF3 and previous investigations in superfluid 3He-A are compared. © Kazan Federal University (KFU)

ЦИТОГЕНЕТИЧЕСКИЙ СТАТУС БОЛЬНЫХ РАКОМ ЖЕЛУДКА

The aim was to identify cytogenetic disorders, proliferative activity and apoptosis in cells exfoliated buccal and nasal epithelium in patients with gastric cancer. The study involved 10 patients with an established diagnosis. The control group included 30 healthy people. It has been revealed that all this parameters were increased in buccal and nasal epithelium in patients with gastric cancer than in healthy people. The detected changes are systemic in nature and reflect the overall condition of the body. Moreover, we show reduction of karyological parameters after radical treatment, which indicates their prognostic significance.Целью было выявление цитогенетических нарушений, нарушений пролиферативной активности клеток и апоптоза в эксфолиативных клетках буккального и назального эпителия у больных с впервые диагностированным раком желудка. Обследовано 10 пациентов с установленными диагнозами. В группу контроля вошли 30 условно здоровых людей. Показано увеличение доли клеток с цитогенетическими нарушениями в буккальном и назальном эпителии у больных раком желудка по сравнению со здоровыми. Выявленные изменения носят системный характер и отражают общее состояние организма. Кроме того, показано снижение уровня кариологических показателей после радикального лечения, что свидетельствует об их прогностическом значении.

Nano-motion Dynamics are Determined by Surface-Tethered Selectin Mechanokinetics and Bond Formation

The interaction of proteins at cellular interfaces is critical for many biological processes, from intercellular signaling to cell adhesion. For example, the selectin family of adhesion receptors plays a critical role in trafficking during inflammation and immunosurveillance. Quantitative measurements of binding rates between surface-constrained proteins elicit insight into how molecular structural details and post-translational modifications contribute to function. However, nano-scale transport effects can obfuscate measurements in experimental assays. We constructed a biophysical simulation of the motion of a rigid microsphere coated with biomolecular adhesion receptors in shearing flow undergoing thermal motion. The simulation enabled in silico investigation of the effects of kinetic force dependence, molecular deformation, grouping adhesion receptors into clusters, surface-constrained bond formation, and nano-scale vertical transport on outputs that directly map to observable motions. Simulations recreated the jerky, discrete stop-and-go motions observed in P-selectin/PSGL-1 microbead assays with physiologic ligand densities. Motion statistics tied detailed simulated motion data to experimentally reported quantities. New deductions about biomolecular function for P-selectin/PSGL-1 interactions were made. Distributing adhesive forces among P-selectin/PSGL-1 molecules closely grouped in clusters was necessary to achieve bond lifetimes observed in microbead assays. Initial, capturing bond formation effectively occurred across the entire molecular contour length. However, subsequent rebinding events were enhanced by the reduced separation distance following the initial capture. The result demonstrates that vertical transport can contribute to an enhancement in the apparent bond formation rate. A detailed analysis of in silico motions prompted the proposition of wobble autocorrelation as an indicator of two-dimensional function. Insight into two-dimensional bond formation gained from flow cell assays might therefore be important to understand processes involving extended cellular interactions, such as immunological synapse formation. A biologically informative in silico system was created with minimal, high-confidence inputs. Incorporating random effects in surface separation through thermal motion enabled new deductions of the effects of surface-constrained biomolecular function. Important molecular information is embedded in the patterns and statistics of motion

Time-temperature dependent fracture toughness of PMMA

A toughness-biased Ree-Eyring relationship gives a good description of fracture toughness data of PMMA over a range of temperatures (283 to 353 K) and crack velocities (10 −5 to 1 m sec −1 ). Fracture toughness was measured by Gurney's sector method. The activation energy associated with the equation supports earlier work which suggests that, in the same temperature and velocity range, cracking in PMMA is controlled by craze growth, which is governed by secondary ( β ) molecular processes. Unstable cracking at moderate velocities (10 −2 to 1 m sec −1 ) seems to be produced by an isothermal/adiabatic transformation; an analysis for the onset of instability is given. At temperatures below 283 K, changes in toughness behaviour are seen, and below 243 K no stable cracking at all was obtained. A discussion is given of various methods of characterizing resistance to cracking, and methods of transforming R (à, T ) and K (à, T ) data are compared.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44668/1/10853_2004_Article_BF00540829.pd