Interactions of the magnetospheres of stars and close-in giant planets

Since the first discovery of an extrasolar planetary system more than a decade ago, hundreds more have been discovered. Surprisingly, many of these systems harbor Jupiter-class gas giants located close to the central star, at distances of 0.1 AU or less. Observations of chromospheric 'hot spots' that rotate in phase with the planetary orbit, and elevated stellar X-ray luminosities,suggest that these close-in planets significantly affect the structure of the outer atmosphere of the star through interactions between the stellar magnetic field and the planetary magnetosphere. Here we carry out the first detailed three-dimensional MagnetoHydroHynamics (MHD) simulation containing the two magnetic bodies and explore the consequences of such interactions on the steady-state coronal structure. The simulations reproduce the observable features of 1) increase in the total X-ray luminosity, 2) appearance of coronal hot spots, and 3) phase shift of these spots with respect to the direction of the planet. The proximate cause of these is an increase in the density of coronal plasma in the direction of the planet, which prevents the corona from expanding and leaking away this plasma via a stellar wind. The simulations produce significant low temperature heating. By including dynamical effects, such as the planetary orbital motion, the simulation should better reproduce the observed coronal heating

The Dynamics of Stellar Coronae Harboring Hot-jupiters II. A Space Weather Event on A Hot-jupiter

We carry out a numerical simulation depicting the effects of a Coronal Mass Ejection (CME) event on a close-in giant planet in an extrasolar system. We drive the CME in a similar manner as in simulations of space weather events on Earth. The simulation includes the planetary orbital motion, which leads to the forming of a comet-like planetary magnetotail which is oriented almost perpendicular to the direction of propagation of the CME. The combination of this feature and the fact that the CME does not expand much by the time it reaches the planet leads to a unique CME-magnetosphere interaction, where the CME itself is highly affected by the presence of the planetary magnetosphere. We find that the planet is well-shielded from CME penetration, even for a relatively weak internal magnetic field. The planetary angular momentum loss associated with such an event is negligible compared to the total planetary angular momentum. We also find that the energy which is deposited in the magnetosphere is much higher than in the case of the Earth, and our simulation suggests there is a large-scale change in the orientation of the magnetosphere-ionosphere current system during the CME event.Comment: 16 pages, 10 figures, accepted to Ap

Observation of Spin Relaxation Anisotropy in Semiconductor Quantum Wells

Spin relaxation of two-dimensional electrons in asymmetrical (001) AlGaAs quantum wells are measured by means of Hanle effect. Three different spin relaxation times for spins oriented along [110], [1-10] and [001] crystallographic directions are extracted demonstrating anisotropy of D'yakonov-Perel' spin relaxation mechanism. The relative strengths of Rashba and Dresselhaus terms describing the spin-orbit coupling in semiconductor quantum well structures. It is shown that the Rashba spin-orbit splitting is about four times stronger than the Dresselhaus splitting in the studied structure.Comment: 4 pages, 3 figure

Показатели окислительного метаболизма и антиоксидантной защиты у больных хроническим обструктивным бронхитом, осложненным хроническим легочным сердцем, и их изменения в процессе лечения

Nowadays there is no a unique approach for evaluation of a role of lipid peroxidation (LP) and its regulation in chronic obstructive bronchitis (COB) complicated by the chronic cor pulmonale (CCP).The aim of our trial was to investigate the LP, the antioxidant defence system (AODS) and the proteases — antiproteases system in patients with COB complicated by the CCP and also to determine opportunities for a pharmacological correction of their disorders.Forty-eight patients aged 28 to 52 years (the average age was 43±1.7 years) suffering from COB complicated by the CCP were examined. Among them 36 persons received the antioxidant drug cytochrome С and 12 ones formed the comparative group. The controls were 14 healthy persons with the average age of 44±1.0 years. We studied initial parameters of LP-AODS in erythrocytes and blood plasma, hemodymanics parameters and their changes under the treatment.The patients with COB complicated by the CCP were found to increase LP products level and lysosomal and proteolytic enzymes activity. The activity of antioxidant enzymes and proteases’ inhibitors were noted to reduce simultaneously. The vigour of these shifts depended on a respiratory failure severity and respiratory system's structural disorders. A combination of cytochrome С and enalapril in patients with COB complicated by the CCP decreased pulmonary hypertension, improved the central and peripheral haemodynamics, blood gas content and acid-and-alkaline blood condition more effective than a traditional therapy. Such the dynamics facilitates shortening the inpatient period and improves the course of the disease.До настоящего времени отсутствует единая концепция в оценке значимости реакция перекисного окисления липидов (ПОЛ) и систем их регуляции при хроническом обструктивном бронхите (ХОБ), осложненном хроническим легочным сердцем (ХЛС).Цель нашего исследования — изучить показатели ПОЛ, антиоксидантной защиты (АОС), систему протеаз — ингибиторы протеаз у больных ХОБ, осложненным ХЛС, и определить возможность фармакологической регуляции этих нарушений.Обследовано 48 пациентов в возрасте от 28 до 52 лет (в среднем 43±1,7 года) с ХОБ, осложненным ХЛС, из них 36 человек получали антиоксидант цитохром С, 12 человек составили группу сравнения. Группу контроля составили 14 практически здоровых лиц, средний возраст 44±1 года. Изучали исходные показатели ПОЛ-АОС в эритроцитах и плазме крови и показатели гемодинамики, а также их динамику на фоне лечения.Установлено, что у больных ХОБ, осложненным ХЛС, повышены содержание продуктов ПОЛ, активность лизосомальных и протеолитических ферментов. Параллельно отмечалось снижение активности антиоксидантных ферментов и ингибиторов протеаз. Выраженность этих изменений зависела от степени дыхательной недостаточности и структурных изменений бронхолегочной системы. Использование цитохрома С в сочетании с эналаприлом в комплексном лечении больных ХОБ, осложненном ХЛС, позволяет достичь большего, чем при традиционном лечении, снижения легочной гипертензии, улучшить показатели центральной и периферической гемодинамики, газового и кислотнощелочного состояния крови, что способствует сокращению сроков стационарного лечения и улучшает течение заболевания

Searching for star-planet magnetic interaction in CoRoT observations

Close-in massive planets interact with their host stars through tidal and magnetic mechanisms. In this paper, we review circumstantial evidence for star-planet interaction as revealed by the photospheric magnetic activity in some of the CoRoT planet-hosting stars, notably CoRoT-2, CoRoT-4, and CoRoT-6. The phenomena are discussed in the general framework of activity-induced features in stars accompanied by hot Jupiters. The theoretical mechanisms proposed to explain the activity enhancements possibly related with hot Jupiter are also briefly reviewed with an emphasis on the possible effects at photospheric level. The unique advantages of CoRoT and Kepler observations to test these models are pointed out.Comment: Invited review paper accepted by Astrophysics and Space Science, 13 pages, 5 figure

The current state of imaging techniques in the detection of prostate cancer

In the review we have described imaging techniques used in the detection of prostate cancer. The role of ultrasound techniques, magnetic resonance imaging, positron emission tomography, computed tomography are reviewed. We have compared the operating characteristics of imaging techniques. The advantages and disadvantages of the methods are pointed.В обзоре рассмотрены методы визуализации используемые в выявлении рака предстатель-ной железы. Рассмотрена роль ультразвуковых методов, магнитной резонансной томографии, позитронно эмиссионной томографии, компьютерной томографии. На основании данных литературы проведено сопоставление операционных характиристик различных методик. Рассмотрены преимущества и недостатки методов

Future exoplanet research: XUV (EUV and X-ray) detection and characterization

This chapter gives an overview of the current status of XUV research in exoplanets and highlights the prospects of future observations. Fundamental questions about the formation and the physical and chemical evolution of exoplanets, particularly hot Jupiters, are addressed through the different lines of XUV research: these comprise XUV irradiation of planetary atmospheres by the host stars, and consequent mass loss and atmospheric evaporation; X-ray and UV transits in exoplanet systems; and Star-Planet Interactions, most often determined by magnetic and tidal forces. While no other UV instrumentation as powerful as that carried by the Hubble Space Telescope will be available for detailed studies in the foreseeable future, the discovery potential of future revolutionary X-ray observatories, such as ATHENA and Lynx, will provide accurate atmosphere characterization and will make strides towards establishing the physics of the interactions between exoplanets and their host stars

ИСПОЛЬЗОВАНИЕ 320-СРЕЗОВОЙ ПЕРФУЗИОННОЙ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ В ВИЗУАЛИЗАЦИИ РАКА ПРЕДСТАТЕЛЬНОЙ ЖЕЛЕЗЫ

Visualization of prostate cancer remains an actual problem in urology and oncology. Purpose of the study – evaluation of prostate cancer visualization using 320-slice perfusion computed tomography (PCT). PCT results of 15 patients with suspected prostate cancer were evaluated. Studies were performed with the 320-slice spiral computed tomography Aquilion One (Toshiba, Japan). Perfusion of the prostate was calculated by the maximum gradient. Next, the areas of interest were placed on each perfusion map. For each of the areas of interest, the following indicators were calculated: the average blood flow velocity, normalized blood flow velocity, the difference of blood flow velocity in the contralateral areas of interest, the difference of the normalized blood flow velocity in the contralateral areas of interest. Differences between indexes depending on the results of histological examination for each area of interest were evaluated by the variance analysis and by pairwise comparison with the Tukey’s criterion. Statistical significance of differences was assessed by the specialized computer language R v 3.2, using pROC packets. Totally, 180 biopsies were obtained. 19 – prostate cancer Σ Gleason 6, 17 – prostate cancer Σ Gleason 7, 5 – prostate cancer Gleason Σ 8, 7 – inflammation, 121 – not pathological, 11 – prostatic intraepithelial neoplasia (PIN). The areas under the ROC curves for the studied parameters were: average blood flow velocity 0.6343, normalized blood flow velocity 0.5300, difference of blood flow velocity in contralateral areas of interest 0.5875, difference of normalized blood flow velocity in the contralateral areas of interest 0.6263. The results of our study shows low sensitivity of the method in detection of lowgrade prostate cancer.Визуализация рака предстательной железы (РПЖ) остается актуальной проблемой в урологии и онкологии. Цель исследования – оценка возможности визуализации РПЖ с помощью 320срезовой перфузионной компьютерной томографии (ПКТ). Были оценены результаты обследования 15 пациентов с подозрением на РПЖ. Исследования были выполнены на 320срезовом спиральном компьютерном томографе Aquilion One (Toshiba, Япония). Перфузию предстательной железы вычисляли методом максимального градиента. Далее на каждой перфузионной карте размещали зоны интереса. Для каждой из зон интереса рассчитывали следующие показатели: средняя скорость кровотока, нормализованная скорость кровотока, разница скорости кровотока в контрлатеральных зонах интереса, разница нормализованной скорости кровотока в контрлатеральных зонах интереса. Различия между показателями в зависимости от результатов гистологического исследования каждой из зон интереса оценивали дисперсионным анализом с последующим попарным сравнением с критерием Тьюки. Статистическую значимость различий оценивали в специализированном языке программирования R v3.2, с применением пакетов «pROC». Всего было получено 180 биоптатов. Из них 19 – РПЖ Σ Глисона 6, 17 – РПЖ Σ Глисона 7, 5 – РПЖ Σ Глисона 8, 7 – воспаление, 121 – отсутствие патологических изменений, 11– простатическая интраэпителиальная неоплезия. Площади под ROC-кривыми изучаемых показателей: средняя скорость кровотока – 0,6343, нормализованная скорость кровотока – 0,5300, разница скорости кровотока в контрлатеральных зонах интереса – 0,5875, разница нормализованной скорости кровотока в контрлатеральных зонах интереса – 0,6263. Результаты нашего исследования демонстрируют малую чувствительность метода в выявлении РПЖ низкой степени злокачественности