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

Optics of spin-noise-induced gyrotropy of asymmetric microcavity

The optical gyrotropy noise of a high-finesse semiconductor Bragg microcavity with an embedded quantum well (QW) is studied at different detunings of the photon mode and the QW exciton resonances. A strong suppression of the noise magnitude for the photon mode frequencies lying above exciton resonances is found. We show that such a critical behavior of the observed optical noise power is specific of asymmetric Fabry-Perot resonators. As follows from our analysis, at a certain level of intracavity loss, the reflectivity of the asymmetric resonator vanishes, while the polarimetric sensitivity to the gyrotropy changes dramatically when moving across the critical point. The results of model calculations are in a good agreement with our experimental data on the spin noise in a single-quantum-well microcavity and are confirmed also by the spectra of the photo-induced Kerr rotation in the pump-probe experiments.Comment: 6 pages, 5 figure

Calculation of Oil-saturated Sand Soils’ Heat Conductivity

Nowadays, there are significant heavy high-viscosity oil reserves in the Russian Federation with oil recovery coefficient not higher than 0.25-0.29 even with applying modern and efficient methods of oil fields development. Thermal methods are the most promising out of the existing ways of development, main disadvantage of which is large material costs, leading to the significant rise in the cost of extracted oil. Thus, creating more efficient thermal methods and improving the existing ones, is the task of great importance in oil production. One of the promising trends in enhancing thermal methods of oil recovery is the development of bottomhole electric steam generators. Compared to the traditional methods of thermal-steam formation treatment, which involve steam injection from surface, well electrothermal devices can reduce energy losses and improve the quality of steam injected into the formation. For successful and efficient organization of oil production and rational development of high-viscosity oil fields using well electrothermal equipment, it is necessary to take into account the pattern of heat propagation, both in the reservoir and in the surrounding space, including the top and bottom. One of the main values characterizing this process is the heat conductivity λ of oil-bearing rocks.  The article describes composition of typical oil-saturated sand soils, presents studies of heat and mass transfer in oil-saturated soils, reveals the effect of various parameters on the heat conductivity of a heterogeneous system, proposes a method for calculating the heat conductivity of oil-bearing soils by sequential reduction of a multicomponent system to a two-component system and proves the validity of the proposed approach by comparing acquired calculated dependencies and experimental data

КОАГУЛЯЦІЙНИЙ ПОТЕНЦІАЛ КРОВІ У ХВОРИХ НА ХРОНІЧНЕ ОБСТРУКТИВНЕ ЗАХВОРЮВАННЯ ЛЕГЕНЬ ПРОФЕСІЙНОЇ ЕТІОЛОГІЇ РІЗНОГО СТУПЕНЯ ТЯЖКОСТІ

Introduction. Chronic obstructive pulmonary disease (COPD) of professional etiology, which is accompanied not only by changes in the respiratory tract, but also by changes in the hemostatic system takes an important place among diseases of the respiratory system. The aim of the study – to evaluate the system of blood coagulation in COPD of a professional etiology of various severity. Research Methods. The results of studies of capillary and venous blood of 112 workers of the mining industry with COPD with various severity were analyzed. Among the patients, 34 people had stage I disease, 40 people – stage II, 38 people – stage III, 29 practically healthy persons made up a control group. The state of the hemostatic system was assessed by the following parameters: platelet count, fibrinogen concentration, activated partial thromboplastin time, thrombin time, international normalized ratio, prothrombin index, prothrombin ratio. Results and Discussion. An analysis of the prothrombin profile indicates that the levels of coagulation cascade factors change in stage II-III COPD patients, which indicates a disruption in the external link of the blood coagulation system. With increasing severity of COPD of professional etiology, changes in the levels of coagulation cascade factors indicated abnormalities of the hemostatic system in the direction of hypercoagulation and depression of the fibrinolytic potential of the blood. Conclusions. During the course of COPD of professional etiology, there are violations in the coagulation unit of hemostasis towards hypercoagulability together with an increase in the severity of the disease. Disturbance of the coagulation unit of hemostasis in patients with COPD of professional etiology occurs mainly along the external path of blood clotting.  Вступление. Важное место среди заболеваний дыхательной системы занимает хроническая обструктивная болезнь легких (ХОБЛ) профессиональной этиологии, которая сопровождается изменениями не только в респираторном тракте, но и в системе гемостаза. Цель исследования – оценить систему свертывания крови при течении ХОБЛ профессиональной этиологии различной степени тяжести. Методы исследования. Проанализированы результаты исследований капиллярной и венозной крови 112 работников горнодобывающей промышленности, больных ХОБЛ различной степени тяжести. Среди пациентов 34 человека имели І стадию заболевания, 40 человек – II стадию, 38 человек – III стадию, 29 практически здоровых лиц составили контрольную группу. Состояние системы гемостаза оценивали по таким параметрам, как: количество тромбоцитов, концентрация фибриногена, уровни активированного частичного тромбопластинового времени, тромбинового времени, международного нормализованного отношения, протромбинового индекса, протромбинового отношения. Результаты и обсуждение. Анализ показателей протромбинового профиля показал, что у больных ХОБЛ II–III стадий преимущественно менялись уровни факторов коагуляционного каскада, что свидетельствовало о нарушении во внешнем звене системы свертывания крови. По мере увеличения тяжести течения ХОБЛ профессиональной этиологии изменения уровней факторов коагуляционного каскада указывали на нарушения системы гемостаза в сторону гиперкоагуляции и депрессии фибринолитического потенциала крови. Выводы. При течении ХОБЛ профессиональной этиологии происходят нарушения в коагуляционном звене гемостаза в сторону гиперкоагуляции вместе с увеличением тяжести заболевания. Нарушения в свертывающем звене гемостаза у больных ХОБЛ профессиональной этиологии отмечают в основном по внешнему пути свертывания крови.Вступ. Важливе місце серед захворювань дихальної системи займає хронічне обструктивне захворювання легень (ХОЗЛ) професійної етіології, яке супроводжується змінами не лише в респіраторному тракті, але і в системі гемостазу. Мета дослідження – оцінити систему згортання крові за перебігу ХОЗЛ професійної етіології різного ступеня тяжкості. Методи дослідження. Проаналізовано результати досліджень капілярної та венозної крові 112 працівників гірничодобувної промисловості, хворих на ХОЗЛ різного ступеня тяжкості. Серед пацієнтів 34 особи мали І стадію захворювання, 40 осіб – ІІ стадію, 38 осіб – ІІІ стадію, 29 практично здорових осіб становили контрольну групу. Стан системи гемостазу оцінювали за такими параметрами, як: кількість тромбоцитів, концентрація фібриногену, рівні активованого часткового тромбопластинового часу, тромбінового часу, міжнародного нормалізованого відношення, протромбінового індексу, протромбінового відношення. Результати й обговорення. Аналіз показників протромбінового профілю показав, що у хворих на ХОЗЛ ІІ–ІІІ стадій переважно змінювались рівні факторів коагуляційного каскаду, що свідчило про порушення у зовнішній ланці системи згортання крові. У міру збільшення тяжкості перебігу ХОЗЛ професійної етіології зміни рівнів факторів коагуляційного каскаду вказували на порушення системи гемостазу в бік гіперкоагуляції та депресії фібринолітичного потенціалу крові. Висновки. За перебігу ХОЗЛ професійної етіології відбуваються порушення в коагуляційній ланці гемостазу в бік гіперкоагуляції разом зі збільшенням тяжкості захворювання. Порушення в згортувальній ланці гемостазу у хворих на ХОЗЛ професійної етіології відзначають в основному по зовнішньому шляху згортання крові. &nbsp

Characteristics of sputum cellular composition in patients with chronic obstructive pulmonary disease of professional etiology.

Inhalation of high concentrations of various types of dust, in particular of inorganic origin, leads to disruption of the normal mechanism of lung cleaning. A consequence of this is the development of inflammation of the airways with the formation of COPD. The inflammatory response of the airways with exacerbation of COPD is accompanied by the increase in the total number of neutrophils and lymphocytes. This heterogeneous cellular infiltrate is the source of specific biologically active substances that play a significant role in the structural and functional changes in the mucous membrane of the bronchopulmonary system. Sputum formation is one of the main clinical symptoms of respiratory diseases. By the parameters of the cellular composition of sputum, it is possible to determine the pathogenetic variant and the severity of the inflammatory response of the respiratory mucosa. The aim of the work was to study the cellular composition in the spontaneous sputum of COPD patients of mining industry. Cytological and statistical methods of investigation were used to achieve this goal. The study of the characteristics of the cell composition of sputum, depending on the degree of severity of COPD of professional etiology, is relevant and informative and allows to evaluate the activity and role of local inflammation in the development and course of the disease. With an increase in the severity of bronchial obstruction in sputum, the total number of cellular elements, neutrophils and lymphocytes increases. The feature of local inflammation developing in the initial stages of COPD of professional etiology is the predominance of macrophages in sputum. With worsening of the severity of the disease course, when the inflammation acquires a persistent character, the number of neutrophils and lymphocytes increases in sputum

Characteristics of sputum cellular composition in patients with chronic obstructive pulmonary disease of professional etiology.

Inhalation of high concentrations of various types of dust, in particular of inorganic origin, leads to disruption of the normal mechanism of lung cleaning. A consequence of this is the development of inflammation of the airways with the formation of COPD. The inflammatory response of the airways with exacerbation of COPD is accompanied by the increase in the total number of neutrophils and lymphocytes. This heterogeneous cellular infiltrate is the source of specific biologically active substances that play a significant role in the structural and functional changes in the mucous membrane of the bronchopulmonary system. Sputum formation is one of the main clinical symptoms of respiratory diseases. By the parameters of the cellular composition of sputum, it is possible to determine the pathogenetic variant and the severity of the inflammatory response of the respiratory mucosa. The aim of the work was to study the cellular composition in the spontaneous sputum of COPD patients of mining industry. Cytological and statistical methods of investigation were used to achieve this goal. The study of the characteristics of the cell composition of sputum, depending on the degree of severity of COPD of professional etiology, is relevant and informative and allows to evaluate the activity and role of local inflammation in the development and course of the disease. With an increase in the severity of bronchial obstruction in sputum, the total number of cellular elements, neutrophils and lymphocytes increases. The feature of local inflammation developing in the initial stages of COPD of professional etiology is the predominance of macrophages in sputum. With worsening of the severity of the disease course, when the inflammation acquires a persistent character, the number of neutrophils and lymphocytes increases in sputum

Continuous time crystal in an electron-nuclear spin system: stability and melting of periodic auto-oscillations

Crystals spontaneously break the continuous translation symmetry in space, despite the invariance of the underlying energy function. This has triggered suggestions of time crystals analogously lifting translational invariance in time. Originally suggested for closed thermodynamic systems in equilibrium, no-go theorems prevent the existence of time crystals. Proposals for open systems out of equilibrium led to the observation of discrete time crystals subject to external periodic driving to which they respond with a sub-harmonic response. A continuous time crystal is an autonomous system that develops periodic auto-oscillations when exposed to a continuous, time-independent driving, as recently demonstrated for the density in an atomic Bose-Einstein condensate with a crystal lifetime of a few ms. Here we demonstrate an ultra-robust continuous time crystal in the nonlinear electron-nuclear spin system of a tailored semiconductor with a coherence time exceeding hours. Varying the experimental parameters reveals huge stability ranges of this time crystal, but allows one also to enter chaotic regimes, where aperiodic behavior appears corresponding to melting of the crystal. This novel phase of matter opens the possibility to study systems with nonlinear interactions in an unprecedented way.Comment: 12 figures, 17 page

Mode locking of hole spin coherences in CsPb(Cl, Br)3 perovskite nanocrystals

The spin physics of perovskite nanocrystals with confined electrons or holes is attracting increasing attention, both for fundamental studies and spintronic applications. Here, stable lead halide perovskite nanocrystals embedded in a fluorophosphate glass matrix are studied by time-resolved optical spectroscopy to unravel the coherent spin dynamics of holes and their interaction with nuclear spins of the 207Pb isotope. We demonstrate the spin mode locking effect provided by the synchronization of the Larmor precession of single hole spins in each nanocrystal in the ensemble that are excited periodically by a laser in an external magnetic field. The mode locking is enhanced by nuclei-induced frequency focusing. An ensemble spin dephasing time of a nanosecond and a single hole spin coherence time of T2 = 13 ns are measured. The developed theoretical model accounting for the mode locking and nuclear focusing for randomly oriented nanocrystals with perovskite band structure describes the experimental data very well