Analysis of functional condition of cardiorespiratory system of qualified and entrant weight lifters

This article provides data of the analysis of functional condition of cardio respiratory system of qualified and entrant weight lifter

The effect of oxide precipitates on minority carrier lifetime in n-type silicon

Supersaturated levels of interstitial oxygen in Czochralski silicon can lead to the formation of oxide precipitates. Although beneficial from an internal gettering perspective, oxygen-related extended defects give rise to recombination which reduces minority carrier lifetime. The highest efficiency silicon solar cells are made from n-type substrates in which oxide precipitates can have a detrimental impact on cell efficiency. In order to quantify and to understand the mechanism of recombination in such materials, we correlate injection level-dependent minority carrier lifetime data measured with silicon nitride surface passivation with interstitial oxygen loss and precipitate concentration measurements in samples processed under substantially different conditions. We account for surface recombination, doping level, and precipitate morphology to present a generalised parameterisation of lifetime. The lifetime data are analysed in terms of recombination activity which is dependent on precipitate density or on the surface area of different morphologies of precipitates. Correlation of the lifetime data with interstitial oxygen loss data shows that the recombination activity is likely to be dependent on the precipitate surface area. We generalise our findings to estimate the impact of oxide precipitates with a given surface area on lifetime in both n-type and p-type silicon

Right Ventricular Tissue Doppler Assessment in Space During Circulating Volume Modification using the Braslet-M Device

This joint U.S. - Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, which effectively reduces the volume returning to the heart in the central circulation. A novel methodology was tested on the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the Braslet-on-occlusion cuffs, as well as to modified Valsalva and Mueller maneuvers. Baseline echocardiographic tissue Doppler imaging (TDI) of the right ventricular free wall with no Braslet applied shows early diastolic E' (16 cm/sec), late diastolic A' (14 cm/sec), and systolic (12 cm/sec) velocities compatible with normal subjects on Earth. TDI of the RV free wall with Braslet applied shows that early diastolic E' decreased by 50% (8 cm/sec), late diastolic A' increased by 45%, and systolic S' remains unchanged. TDI of the RV free wall approximately 8 beats after the Braslet was released shows early diastolic E' (8 cm/sec), late diastolic A' (12 cm/sec), and systolic S' (13 cm/sec) velocities. During this portion of the release, early diastolic E' did not recover to baseline values but late diastolic A' and systolic S' recovered to pre-Braslet values. The pre-systolic cross-sectional area of the internal jugular vein with Braslet off was 1.07 cm(sup 2) and 1.13 cm(sup 2) 10 min after the Braslet was applied. The presystolic cross-sectional area of the common femoral vein with Braslet off was 0.50 cm(sup 2), and was 0.54 cm(sup 2) 10 min after the Braslet was applied. The right ventricular myocardial performance Tei index also was calculated for comparison with typical values found in healthy subjects on Earth. Baseline and Braslet-on values for Tei index were 0.25 and 0.22 respectively. Braslet Tei indices are within normal ranges found in healthy subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of this study. Tissue Doppler imaging of the right ventricle revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower-extremity interstitial and vascular space after only 10 minutes of application. This report demonstrates that Braslet application affects right ventricular physiology in long-duration space flight based on TDI and that this effect is in part due to venous hemodynamics

Molecular line radiative transfer in protoplanetary disks: Monte Carlo simulations versus approximate methods

We analyze the line radiative transfer in protoplanetary disks using several approximate methods and a well-tested Accelerated Monte Carlo code. A low-mass flaring disk model with uniform as well as stratified molecular abundances is adopted. Radiative transfer in low and high rotational lines of CO, C18O, HCO+, DCO+, HCN, CS, and H2CO is simulated. The corresponding excitation temperatures, synthetic spectra, and channel maps are derived and compared to the results of the Monte Carlo calculations. A simple scheme that describes the conditions of the line excitation for a chosen molecular transition is elaborated. We find that the simple LTE approach can safely be applied for the low molecular transitions only, while it significantly overestimates the intensities of the upper lines. In contrast, the Full Escape Probability (FEP) approximation can safely be used for the upper transitions (J_{\rm up} \ga 3) but it is not appropriate for the lowest transitions because of the maser effect. In general, the molecular lines in protoplanetary disks are partly subthermally excited and require more sophisticated approximate line radiative transfer methods. We analyze a number of approximate methods, namely, LVG, VEP (Vertical Escape Probability) and VOR (Vertical One Ray) and discuss their algorithms in detail. In addition, two modifications to the canonical Monte Carlo algorithm that allow a significant speed up of the line radiative transfer modeling in rotating configurations by a factor of 10--50 are described.Comment: 47 pages, 12 figures, accepted for publication in Ap

Black-hole concept of a point-like nucleus with supercritical charge

The Dirac equation for an electron in the central Coulomb field of a point-like nucleus with the charge greater than 137 is considered. This singular problem, to which the fall-down onto the centre is inherent, is addressed using a new approach, based on a black-hole concept of the singular centre and capable of producing cut-off-free results. To this end the Dirac equation is presented as a generalized eigenvalue boundary problem of a self-adjoint operator. The eigenfunctions make complete sets, orthogonal with a singular measure, and describe particles, asymptotically free and delta-function-normalizable both at infinity and near the singular centre $r=0$. The barrier transmission coefficient for these particles responsible for the effects of electron absorption and spontaneous electron-positron pair production is found analytically as a function of electron energy and charge of the nucleus. The singular threshold behaviour of the corresponding amplitudes substitutes for the resonance behaviour, typical of the conventional theory, which appeals to a finite-size nucleus.Comment: 22 pages, 5 figures, LATEX requires IOPAR

Чрескожный обход левого желудочка как метод краткосрочной механической поддержки кровообращения перед трансплантацией сердца у пациентов с высокой предтрансплантационной легочной гипертензией (серия клинических наблюдений)

Federation In certain categories of patients with end-stage heart failure (HF), short-term mechanical circulatory support (MSC) is successfully used as a mechanical «bridge» to heart transplantation (HTx). In predominantly left-ventricular (LV) dysfunction, the use of isolated coronary artery bypass, especially amidst high pulmonary hypertension (PH), seems to be a more physiological method of short-term MSC.Objective: to present the results of a series of clinical cases of the use of percutaneous left ventricular assist device (pLVAD) before HTx in potential recipients with predominantly LV dysfunction and concomitant high PH.Materials and methods. Three potential heart recipients with predominantly left-sided HF and high pre-transplant PH (pulmonary vascular resistance, PVR, 4.7–6.6 Wood units) who required MSC due to progression of hemodynamic disorders were included in the study. A standard venous extracorporeal membrane oxygenation (ECMO) cannula (26 F) was used for percutaneous left atrial-femoral artery (LA–FA) bypass. The cannula was passed from the transfemoral route through the interatrial septum into the left atrial cavity. A paracorporeal centrifugal pump provided blood injection through a standard arterial ECMO cannula (15 F).Results. pLVAD unloaded the left ventricle effectively (PCWP reduced from 27–32 to 15–20 mmHg), reduced pre-transplant PH (mean pulmonary artery pressure (mPAP) reduced from 45–53 to 28–33 mmHg) and improved systemic hemodynamics (cardiac index (CI) increased from 1.8–1.9 to 2.1–2.6 l/min/m2 and mean arterial pressure (mAP) from 56–59 to 70–75 mmHg). All these created the prerequisites for subsequent successful HTx. Against the background of pLVAD, transpulmonary pressure gradient (TPG) decreased from 15–25 to 13–15 mmHg, and PVR decreased from 4.7–6.6 to 2.7–3.4 Wood units. pLVAD flow rate was 2.9–3.8 L/min or 1.38–1.83 L/min/m2 at 4700–7100 rpm. pLVAD duration ranged from 4 (n = 1) to 7 (n = 2) days. All patients underwent successful HTx.Conclusion. pLVAD is a highly effective method of short-term MSC in potential recipients with predominantly LV dysfunction and concomitant high PH, leading to rapid regression of the dysfunction against the background of left ventricular unloading. This short-term MSC technique can be successfully realized using standard ECMO cannulas and centrifugal pumps of any modification, without requiring additional special equipment.У определенных категорий пациентов с терминальной сердечной недостаточностью (СН) краткосрочная механическая поддержка кровообращения (МПК) успешно применяется в качестве механического «моста» перед трансплантацией сердца (ТС). При преимущественно левожелудочковом варианте нарушения насосной функции сердца применение изолированного левожелудочкового обхода (ЛЖО), особенно при наличии высокой легочной гипертензии (ЛГ), представляется более физиологическим методом краткосрочной МПК.Цель исследования: представление результатов серии клинических наблюдений применения чрескожного левожелудочкового обхода (чЛЖО) перед ТС у потенциальных реципиентов с преимущественно левожелудочковой дисфункцией и сопутствующей высокой ЛГ.Материалы и методы. В исследование включили трех потенциальных реципиентов сердца с преимущественно левожелудочковым вариантом СН и высокой предтрансплантационной ЛГ (ЛСС 4,7–6,6 ед. Вуда), нуждавшихся в МПК в связи с прогрессированием гемодинамических нарушений. Для чЛЖО по схеме «левое предсердие – бедренная артерия» использовали стандартную венозную ЭКМО-канюлю (26 F), проведенную из трансфеморального доступа через межпредсердную перегородку в полость левого предсердия. Паракорпоральный центрифужный насос обеспечивал нагнетание крови через стандартную артериальную ЭКМО-канюлю (15 F).Результаты исследования. чЛЖО обеспечил эффективную разгрузку левых отделов сердца (снижение ЗДЛА с 27–32 до 15–20 мм рт. ст.), снижение предтрансплантационной ЛГ (снижение ДЛАср. с 45–53 до 28–33 мм рт. ст.) и улучшение системной гемодинамики (увеличение СИ с 1,8–1,9 до 2,1–2,6 л/мин/м2 и АДср. с 56–59 до 70–75 мм рт. ст.), что создало предпосылки для последующего успешного выполнения ТС. На фоне чЛЖО ТПГ снизился с 15–25 до 13–15 мм рт. ст., ЛСС – с 4,7–6,6 до 2,7–3,4 ед. Вуда. Объемная скорость чЛЖО составила 2,9–3,8 л/мин, или 1,38–1,83 л/мин/м2 при частоте оборотов насоса 4700–7100 в мин. Продолжительность чЛЖО составила от 4 (n = 1) до 7 (n = 2) суток. Всем пациентам была выполнена успешная ТС.Заключение. чЛЖО является высокоэффективным методом краткосрочной МПК у потенциальных реципиентов с преимущественным нарушением насосной функции левого желудочка и сопутствующей ЛГ, приводя к ее быстрому регрессу на фоне объемной разгрузки левых отделов сердца. Данный метод краткосрочной МПК может быть успешно реализован с использованием стандартных ЭКМО-канюль и центрифужного насоса любой модификации, не требуя дополнительного специального оборудования

The politics of in/visibility: carving out queer space in Ul'yanovsk

<p>In spite of a growing interest within sexualities studies in the concept of queer space (Oswin 2008), existing literature focuses almost exclusively on its most visible and territorialised forms, such as the gay scene, thus privileging Western metropolitan areas as hubs of queer consumer culture (Binnie 2004). While the literature has emphasised the political significance of queer space as a site of resistance to hegemonic gender and sexual norms, it has again predominantly focused on overt claims to public space embodied in Pride events, neglecting other less open forms of resistance.</p><p> This article contributes new insights to current debates about the construction and meaning of queer space by considering how city space is appropriated by an informal queer network in Ul’ianovsk. The group routinely occupied very public locations meeting and socialising on the street or in mainstream cafés in central Ul’ianovsk, although claims to these spaces as queer were mostly contingent, precarious or invisible to outsiders. The article considers how provincial location affects tactics used to carve out communal space, foregrounding the importance of local context and collective agency in shaping specific forms of resistance, and questioning ethnocentric assumptions about the empowering potential of visibility.</p&gt

Space-VLBI observations of OH maser OH34.26+0.15: low interstellar scattering

We report on the first space-VLBI observations of the OH34.26+0.15 maser in two main line OH transitions at 1665 and 1667 MHz. The observations involved the space radiotelescope on board the Japanese satellite HALCA and an array of ground radio telescopes. The map of the maser region and images of individual maser spots were produced with an angular resolution of 1 milliarcsec which is several times higher than the angular resolution available on the ground. The maser spots were only partly resolved and a lower limit to the brightness temperature 6x10^{12} K was obtained. The maser seems to be located in the direction of low interstellar scattering, an order of magnitude lower than the scattering of a nearby extragalactic source and pulsar.Comment: 8 pages, 2 tables, 9 figures, accepted for publication in MNRA