Ultimate photo-induced Kerr rotation achieved in semiconductor microcavities

Photoinduced Kerr rotation by more than $\pi /2$ radians is demonstrated in planar quantum well microcavity in the strong coupling regime. This result is close to the predicted theoretical maximum of $\pi$. It is achieved by engineering microcavity parameters such that the optical impedance matching condition is reached at the smallest negative detuning between exciton resonance and the cavity mode. This ensures the optimum combination of the exciton induced optical non-linearity and the enhancement of the Kerr angle by the cavity. Comprehensive analysis of the polarization state of the light in this regime shows that both renormalization of the exciton energy and the saturation of the excitonic resonance contribute to the observed optical nonlinearities.Comment: Shortened version prepared to submit in Phys. Rev. Letter

Synthesis and magnetic properties of BiFe1-xCoxO3 (x = 0-0.07)

This research was carried out under the financial support of the Russian Foundation for Basic Research №17-08-00893

Self-assembly of hollow bismuth ferrite spheres

This research was carried out under the financial support of the Russian Foundation for Basic Research №17-08-00893

Spin-glass transition in porous spheres BiFeO3

Magnetic properties of porous spheres BiFeO3 have been studied at temperatures ranging from 2 to 300 K. A transition to cluster spin glass state has been detected in the region of about 100 K. The presence of the transition is confirmed by nonlinear variation of coercive force and the appearance of exchange displacement of magnetic hysteresis loops at temperature below 100 K. Temperature dependence of magnetization for zero-field cooled regime exhibit a maximum at some temperature Tm. The function Tm(H) (H is magneic field) changes in accordance with Almeida-Thouless line. The performed measurements of the frequency dependence of AC susceptibility confirm the behavior of spin glass with spin freezing temperature Tf = 116 K. The critical index zν = 2.5 agrees well with the mean-field theory zν = 2.0. © 2020, ITMO University. All rights reserved.This work was supported by a research program at the Institute of Solid State Chemistry. The authors are grateful to Dr. Maria V. Lukashova (OOO “Tescan”, Saint Petersburg, Russia) for scanning microscopy and 3D FIB-SEM tomography

Spin Texture in a Cold Exciton Gas

We report on the observation of a spin texture in a cold exciton gas in a GaAs/AlGaAs coupled quantum well structure. The spin texture is observed around the exciton rings. The observed phenomena include: a ring of linear polarization, a vortex of linear polarization with polarization perpendicular to the radial direction, an anisotropy in the exciton flux, a skew of the exciton fluxes in orthogonal circular polarizations and a corresponding four-leaf pattern of circular polarization, a periodic spin texture, and extended exciton coherence in the region of the polarization vortex. The data indicate a transport regime where the spin polarization is locked to the direction of particle propagation and scattering is suppressed.Comment: version 2 contains updated supplementary materia

On selection of foxes for enhanced aggressiveness and its correlated implications

The results of a 35-year selection of foxes for aggressive response to humans are reported. Averaged estimates of the phenotypic manifestation of aggressiveness in all selection generations are presented. The dynamics of these estimates shows that the phenotypic response to the selection was obvious only in the first 12 generations. Subsequent selection did not alter the mean aggressiveness score. Analysis of variance was performed for the intergroup variability (among descendants of different mothers) and intragroup variability (among the offspring within a family). The intragroup variability was constantly low. Most likely, the trait is stabilized by maternal prenatal and early neonatal factors. The general tendency in the dynamics of intergroup variability is that it does not decrease over time during selection, no matter how long the population has been under it. It follows from the statistical indices of the phenotypic similarity between parents and offspring that additive interactions are insufficient for the explanation of the persisting variability. The contribution of epistatic interactions is not ruled out, though. Emphasis is laid on the correlated consequences of the selection for aggressiveness and their coordination with the consequences of the selection in the opposite direction, for elimination of aggressive response to humans, or for tameness. The parallelism of correlated changes in the selection in contrasting directions is illustrated by the examples of some physiological and morphological traits. The phenomenon is discussed in the light of classical notions of the resource of cryptic genetic variation and the role of selection in its phenotypic manifestation. Its interpretation also invokes molecular data pointing that some genetic pathways may regulate parameters of both aggression and tameness and that the selection processes in both directions may have some genetic targets in common

TTX-sensitive Na+ and nifedipine-sensitive Ca2+ channels in rat vas deferens smooth muscle cells

The inward currents in single smooth muscle cells (SMC) isolated from epididymal part of rat vas deferens have been studied using whole-cell patch-clamp method. Depolarising steps from holding potential -90 mV evoked inward current with fast and slow components. the component with slow activation possessed voltage-dependent and pharmacological properties characteristic for Ca2+ current carried through L-type calcium channels (I-Ca). the fast component of inward current was activated at around -40 mV, reached its peak at 0 mV, and disappeared upon removal of Na ions from bath solution. This current was blocked in dose-dependent manner by tetrodotoxin (TTX) with an apparent dissociation constant of 6.7 nM. On the basis of voltage-dependent characteristics, TTX sensitivity of fast component of inward current and its disappearance in Na-free solution it is suggested that this current is TTX-sensitive depolarisation activated sodium current (I-Na) Cell dialysis with a pipette solution containing no macroergic compounds resulted in significant inhibition of I-Ca (depression of peak I-Ca by about 81% was observed by 13 min of dialysis), while I-Na remained unaffected during 50 min of dialysis. These data draw first evidence for the existence of TTX-sensitive Na+ current in single SMC isolated from rat vas deferens. These Na+ channels do not appear to be regulated by a phosphorylation process under resting conditions. (C) 1999 Elsevier Science B.V. All rights reserved.Natl Acad Sci Ukraine, Bogomoletz Inst Physiol, Nerve Muscle Physiol Dept, UA-24 Kiev, UkraineUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilWeb of Scienc

Solution combustion synthesis of α-Al2O3 using urea

The processes involved in the solution combustion synthesis of α-Al2O3 using urea as an organic fuel were investigated. The data describing the influence of the relative urea content on the characteristic features of the combustion process, the crystalline structure and the morphology of the aluminium oxide are presented herein. Our data demonstrate that the combustion of stable aluminium nitrate and urea complexes leads to the formation of α-alumina at temperatures of approximately 600-800 °C. Our results, obtained using differential thermal analysis and IR spectroscopy methods, reveal that the low-temperature formation of α-alumina is associated with the thermal decomposition of an α-AlO(OH) intermediate, which was crystallised in the crystal structure of the diaspore. © 2012 Elsevier Ltd and Techna Group S.r.l

Методический подход к оценке уровня адаптивности организационных структур управления компаниями

Purpose: to present and justify a methodical approach to assessing the level of adaptability of organizational management structures to the conditions of a dynamically changing external environment.Methods: a wide range of general scientific methods is used – system analysis, synthesis, graphical interpretation of data. During the study, the method of expert assessments was used to assess the level of adaptability. In order to classify the types of management structures depending on their adaptability, a cluster analysis was carried out.Results: the article presents an approach to the definition of the concepts of "adaptation" and "adaptability" in relation to management structures. In order to develop a methodical approach to assessing the level of adaptability of organizational structures, the types of their adaptation were systematized, the main characteristics of the structures were identified and the scale was developed to assess the level of their adaptability. The use of the expert method made it possible to assess the level of adaptability of the main types of organizational structures to the conditions of a changing business space and rank them depending on this level. As a result of the cluster analysis, all the studied types of management structures were classified depending on their adaptability.Conclusions and Relevance: the developed methodical approach to assessing the level of adaptability of management structures made it possible to determine the adaptive properties of both hierarchical and organic management structures, assess their level of adaptability and identify the most adaptive among them. It has been established that the basis for the successful development of companies in the conditions of turbulent business space is the use of organic structures or changing individual parameters of hierarchical structures in order to increase their adaptability. Adaptation can be carried out using any structure, both traditional hierarchical and organic, by forming new management structures or increasing the adaptability of existing ones. Further research in this area should be devoted to the development of an effective mechanism for adapting management structures to the conditions of a changing business space.Цель статьи – представить и обосновать методический подход по оценке уровня адаптивности организационных структур управления компаниями к условиям динамично меняющейся внешней среды.Методы. Использован широкий спектр общенаучных методов – системного анализа, синтеза, графической интерпретации данных. При проведении исследования для оценки уровня адаптивности использовался метод экспертных оценок. С целью классификации видов структур управления в зависимости от их адаптируемости был проведен кластерный анализ.Результаты работы. В статье представлен подход к определению понятий «адаптация» и «адаптивность» применительно к структурам управления. С целью разработки методического подхода к оценке уровня адаптивности организационных структур проведена систематизация видов их адаптации, выявлены основные характеристики структур и разработана шкала оценки уровня их адаптивности. Использование экспертного метода позволило оценить уровень адаптивности основных видов организационных структур к условиям изменяющегося бизнес-пространства, и проранжировать их в зависимости от этого уровня. В результате проведения кластерного анализа все исследуемые виды структур управления были классифицированы в зависимости от их адаптируемости.Выводы. Разработанный методический подход к оценке уровня адаптивности структур управления позволил определить адаптивные свойства как иерархических, так и органических структур управления, оценить уровень их адаптивности и выявить среди них самые адаптивные. Установлено, что основой успешного развития компаний в условиях турбулентности бизнес-пространства является использование органических структур или изменение отдельных параметров иерархических структур с целью повышения их адаптивности. Адаптация может осуществляться при использовании любой структуры, как традиционной иерархической, так и органической, путем формирования новых структур управления или повышения адаптивности уже существующих. Дальнейшие исследования в этой сфере должны быть посвящены разработке действенного механизма адаптации структур управления к условиям изменяющегося бизнес-пространства

Влияние ранней диагностики травматических повреждений на развитие легочных осложнений у пострадавших с сочетанной травмой

Despite the existing progress in providing care to patients with severe multisystem chest injury using advanced diagnostic methods, a high mortality rate still reaches 20–30%.Aim of study. To assess the impact of early diagnosis and correction of chest injuries on the development of complications in patients with multisystem trauma.Material and methods. The results of diagnosis and treatment of 89 patients with severe multisystem closed chest injury were studied. According to the time of admission to the Institute, the patients were divided into two groups: Group I, who were admitted to the Institute within the first hours after the injury (51 patients), and Group II, who were transferred from other medical institutions on the 3rd–7th day (38). CT was performed as a standard method of diagnosis and monitoring the dynamics of the process. With the development of purulent-inflammatory pulmonary complications, the bacteriological test of bronchoalveolar lavage was performed. Treatment included complex intensive therapy, drainage of the pleural cavity and emergency surgical interventions, if necessary.Results. In Group I, lung contusion occurred in 43 (84%) patients, and after 7-10 days, the contusion foci partially regressed in 20 (46.5%) patients. In 8 (16%) patients with lung rupture, infiltrative changes in the lung were resolved on the 18th-30th day, while 4 (50%) of them had pneumonia outside the contusion zones. In Group II, patients were put on a ventilator and inflammatory changes in the lungs were revealed in 30 patients (79%). Lung rupture associated with the contusion was revealed in 2 (5.2%). When comparing the groups by the composition of the isolated microflora, it was found that in patients of group II, Acinetobacter spp was more often found (46.7% vs. 17.1% in group I patients, p=0.021) and Enterococcus spp. (30.0% and 8.6%, respectively, p=0.058), as well as Klebsiella pneumoniae (46.7% and 37.1%, p=0.6). At the same time, Staphylococcus aureus was not found in these patients, while it was detected in 14.3% of patients from Group I (p=0.09). Medical care in Group I was carried out according to the principles of the “golden hour”: within the first hour from the moment of admission to the patients with the presence of pneumothorax and hemothorax, the pleural cavity was drained. In Group II, this procedure was performed in other medical institutions and in 5 additional patients at the Institute.Conclusions. Early computed tomography diagnosis of multisystem trauma makes it possible to assess the severity of injuries to the chest organs and other areas of the body and determine the treatment tactics. A comprehensive approach to the management of patients, including early diagnosis of trauma, drainage of the pleural cavity, determination of management tactics, bacterial test of the lower respiratory tract discharge, helps reduce infectious complications by an average of 45.46%. Актуальность. Несмотря на имеющийся прогресс в оказании помощи пострадавшим с тяжелой сочетанной травмой с использованием передовых методов диагностики, сохраняется высокий уровень летальности, достигающий 20–30%.Цель исследования. Оценить влияние ранней диагностики и коррекции повреждений груди на развитие осложнений у пострадавших с сочетанной травмой.Материал и методы. Изучены результаты диагностики и лечения 89 пострадавших с тяжелой сочетанной травмой. В соответствии со временем поступления в институт пациенты разделены на две группы: I группа — поступили в институт в первые 3 часа после травмы (51 больной), II — переведены из других лечебных учреждений на 3-и–7-е сутки (38). Компьютерную томографию выполняли как стандартный метод диагностики и контроля за динамикой процесса. При развитии гнойно-воспалительных легочных осложнений проводили бактериологическое исследование бронхоальвеолярного лаважа. Лечебные мероприятия включали в себя комплексную интенсивную терапию, дренирование плевральной полости и при необходимости проведение неотложных хирургических вмешательств.Результаты. В I группе ушиб легких был у 43 пациентов (84%), через 7–10 дней очаги ушиба частично регрессировали у 20 пострадавших (46,5%). При разрыве легкого у 8 (16%) инфильтративные изменения легкого разрешались на 18–30-е сутки, при этом у 4 (50%) из них было присоединение пневмонии вне зон контузии. Во II группе пострадавшие поступали на искусственной вентиляции легких, и воспалительные изменения в легких были у 30 больных (79%). Разрыв легкого на фоне ушиба был у 2 (5,2%). При сравнении групп по составу выделенной микрофлоры обнаружено, что у пациентов II группы чаще выделяли Acinetobacter spp. (46,7% против 17,1% у пациентов I группы, p=0,021) и Enterococcus spp. (30,0% и 8,6% соответственно, p=0,058), а также Klebsiella pneumoniae (46,7% и 37,1%, p=0,6). При этом Staphylococcus aureus у данных пациентов не встречался, тогда как его обнаруживали у 14,3% больных из I группы (p=0,09). Медицинскую помощь в I группе осуществляли по принципам «золотого часа»: в течение первого часа от момента поступления пострадавшим с наличием пневмо- и гемоторакса выполняли дренирование плевральной полости. Во II группе этот прием проводили в других лечебных учреждениях и у 5 пострадавших дополнительно в институте.Выводы. Ранняя компьютерно-томографическая диагностика сочетанной травмы дает возможность оценить тяжесть повреждений органов груди, других областей тела и определить тактику лечения. Комплексный подход к ведению пострадавших, включающий раннюю диагностику травмы, дренирование плевральной полости, определение тактики ведения, бактериальную оценку отделяемого нижних дыхательных путей, способствует снижению инфекционных осложнений в среднем на 45,46%.