Double-exciton component of the cyclotron spin-flip mode in a quantum Hall ferromagnet

We report on the calculation of the cyclotron spin-flip excitation (CSFE) in a spin-polarized quantum Hall system at unit filling. This mode has a double-exciton component which contributes to the CSFE correlation energy but can not be found by means of a mean field approach. The result is compared with available experimental data.Comment: 9 pages, 2 figure

Influence of Silicon on Temperature Dependence of Thermal Conductivity of Al–Si–Fe Alloys

Temperature dependence analysis of thermal conductivity was carried out for series of aluminum alloys with 1% Fe (mass%) and different content of silicon starting from 0% to 6% (mass%). It is shown that the best alloy for heat exchange applications is alloy with 4% of silicon (mass%). Temperature dependence of thermal conductivity shows the strong decreasing character for silicon-alloyed samples in comparison to pure aluminum. Keywords: aluminum–silicon alloys, thermal conductivity, heat exchange, iron, cast alloys, structure, temperatur

Influence of Silicon on Thermal Conductivity at Room Temperature of Al–Si–Fe Alloys

The analysis of densities and thermal conductivities has been performed for cast experimentally made aluminum alloys containing different content of silicon starting from 0% to 12% (mass%). All alloys have been additionally supplemented by iron up to 1% mass for better casting properties. Results have shown a strong tendency of decrease in the thermal conductivity with increasing silicon content. The same character is found for densities behavior. Keywords: aluminum-silicon alloys, thermal conductivity, heat exchange, iron, cast alloys, structure, temperatur

Magnetophonon resonance in photoluminescence excitation spectra of magnetoexcitons in GaAs/Al0.3Ga0.7As superlattice

Strong increase in the intensity of the peaks of excited magneto-exciton (ME) states in the photoluminescence excitation (PLE) spectra recorded for the ground heavy-hole magneto-excitons (of the 1sHH type) has been found in a GaAs/AlGaAs superlattice in strong magnetic field B applied normal to the sample layers. While varying B the intensities of the PLE peaks have been measured as functions of energy separation $\Delta E$ between excited ME peaks and the ground state of the system. The resonance profiles have been found to have maxima at $\Delta E_{\rm max}$ close to the energy of the GaAs LO-phonon. However, the value of $\Delta E_{\rm max}$ depends on quantum numbers of the excited ME state. The revealed very low quantum efficiency of the investigated sample allows us to ascribe the observed resonance to the enhancement of the non-radiative magneto-exciton relaxation rate arising due to LO-phonon emission. The presented theoretical model, being in a good agreement with experimental observations, provides a method to extract 1sHH magneto-exciton ``in-plane" dispersion from the dependence of $\Delta E_{\rm max}$ on the excited ME state quantum numbers.Comment: 9 pages, 6 figure

Association of Interleukin-10 Gene Polymorphisms with Ulcerative Colitis

This literature review is devoted to the study of the role of polymorphic variants of the anti-inflammatory interleukin-10 gene (Interleukin-10, IL10) in the etiology and pathogenesis of ulcerative colitis in patients of various ethnic groups.Aim. To generalize the results obtained from electronic databases on the study of the characteristics of the course of ulcerative colitis in patients of different ethnic groups, taking into account the carriage of IL10 gene polymorphisms.Materials and methods. Twenty-five studies were selected, including four meta-analyzes devoted to the  study of associative relationships of single nucleotide polymorphisms (SNPs) of the IL10 gene isolated from  blood samples at positions -592AA/CA, -819CT, -1082АА/GA, and rs3024505 in the development and course of ulcerative colitis.Results. A number of researchers from Europe, Saudi Arabia report an increased incidence of ulcerative colitis among carriers of the IL10-1082AA SNP and a low incidence among carriers of -592AA. Positive associations of IL10-819CT with the prevalence of ulcerative colitis are presented in single reports from Europe, the Middle East and in a number of studies from Asian countries. However, the identified associations, even within the  same population, are often contradictory. Perhaps the discrepancies are due to the ethnic heterogeneity of the groups in the considered cohorts, and therefore it is necessary to continue epidemiological studies with a large sample size in specific geographic areas

Experience with integrated vacuum system obstetrics «KIWI»

The article presents an analysis of delivery and operative delivery by vaginal application of a vacuum system «KIWI» in Federal State Institution «Uraf Research Institute of Maternity and Infancy of the Federal Agency for high-tech medical care». In 28 women, the labor ended in fetal vacuum extraction, accounting for 1.71% of the total number of operational delivery. The main indications for the operation of vacuum extraction were: the weakness of labor, signs of fetal hypoxia, the deliberate shortening labor in connection with a high degree of myopia. Obtain experience with the system at delivery by caesarean section. The majority of children (60.71 %) after delivery were discharged in satisfactory condition, along with mother. Experience of clinical application of modern system of vacuum extraction «KIWI» suggests the effectiveness of the system in case of weakness of labor activity, fetal hypoxia during the second stage of labor, to avoid severe damage to the central nervous system of the child in critical obstetric situations.В статье представлен анализ течения родов и оперативного родоразрешения через естественные родовые пути с применением вакуумной системы «KIWI» в ФГУ «НИИ ОММ Росмедтехнологий». За время применения данной системы операцией вакуум-экстрации родоразрешены 28 пациенток, что составило 1,71 % от общего числа оперативных родов. Основными показаниями к проведению операции вакуум-экстракции явились: слабость потуг, признаки гипоксии плода, намеренное укорочение потужного периода в связи с миопией высокой степени, перенесенным геморрагическим инсультом. Получен опыт применения данной системы при родоразрешении кесаревым сечением. Основная масса детей (60,71 %) после родоразрешения были выписаны в удовлетворительном состоянии вместе с матерью. Опыт клинического применения современной системы вакуум экстракции «KIWI» позволяет сделать вывод об эффективности системы в случае слабости родовой деятельности, гипоксии плода во втором периоде родов, избежать тяжелых повреждений ЦНС плода в критических акушерских ситуациях

Compact 0.7 mJ/11 ns eye-safe erbium laser

We report on the development of a compact diode-end-pumped eye-safe (similar to 1.54 mu m) passively-cooled Er, Yb:glass laser. The design of this laser is facilitated by the use of a double-pass pumping scheme and a special ZrO2 diffuse reflector for a uniform pump distribution. In the free-running mode, this laser generates 8.2 mJ/3 ms pulses with a slope efficiency of 15%. Passive Q-switching is provided by saturable absorbers made of transparent glass-ceramics containing Co2+:gamma-Ga2O3 or Co2+:MgAl2O4 nanocrystals with a spinel structure. In the latter case, 0.7 mJ/10.5 ns pulses are generated corresponding to >60 kW peak power and good beam quality (M-2 = 1.4). The designed laser is suitable for portable range-finders

Diffusion-induced vortex filament instability in 3-dimensional excitable media

We studied the stability of linear vortex filaments in 3-dimensional (3D) excitable media, using both analytical and numerical methods. We found an intrinsic 3D instability of vortex filaments that is diffusion-induced, and is due to the slower diffusion of the inhibitor. This instability can result either in a single helical filament or in chaotic scroll breakup, depending on the specific kinetic model. When the 2-dimensional dynamics were in the chaotic regime, filament instability occurred via on-off intermittency, a failure of chaos synchronization in the third dimension.Comment: 5 pages, 5 figures, to appear in PRL (September, 1999

Thermal properties and structure of cast carbon-containing invar and superinvar alloys after two-stage annealing

The effect of carbon content on thermal properties of cast superinvar alloys subjected to two-stage annealing is studied. It is shown that carbon improves the casting properties of the alloys but raises the temperature coefficient of linear expansion (CTLE). Two-stage high-temperature annealing makes it possible to remove carbon from the solid solution and to transfer it into graphite, which is accompanied by decrease in the CTLE. © 2013 Springer Science+Business Media New York