Geometrically Thin Disk Accreting Into a Black Hole

A numerical model of a steady state, thin accretion disk with a constant effective speed of sound is presented. We demonstrate that `zero torque' inner boundary condition is a reasonable approximation provided that the disk thickness, including the thickness of the torquing magnetic fields, is small everywhere. It is likely that this conclusion is correct also for non-steady disks, as long as the total thickness at the sonic point, H_c, is much smaller than the radius there, r_c ~ r_{ms}. The very existence of thin disks is not proved or disproved in this work, but such disks are believed to exist for moderate accretion rates. Within our model there is a small torque at r_{ms}, which may increase disk luminosity by several percent. An important result of our analysis is that the physically acceptable steady state solutions in our toy model exist only for \alpha < 0.14 (100 v_s/c)^{1/3}. A significant torque may be applied to a thin disk if there is a large scale magnetic field, like in a modified Blandford-Znajek mechanism.Comment: 37 pages (ApJ preprint format), 14 figures, Additional discussions and figures, Replaced to match the accepted pape

Положительное давление в конце выдоха как фактор, влияющий на церебральное перфузионное давление (экспериментальное исследование)

Objective: to evaluate the effect of positive end-expiratory pressure (PEEP) on cerebral perfusion pressure (CPP) in intracranial hypertension in an experiment using a biological model. Materials and methods. The experiment was carried out on 10 pigs aged 2 months and weighing 17—20 kg. The experimental animals were anesthetized. The authors monitored the following parameters: invasive arterial and central venous pressures, intracranial pressure (ICP), and peak inspiratory pressure. ICP was simulated with a subdurally placed balloon. During mechanical ventilation (MV), PEEP was gradually increased up to 5, 10, 15, and 20 cm H2O. Results. PEEP elevation during MV was accompanied by a progressive rise in intrathoracic pressure and a reduction in mean blood pressure. When PEEP was increased, there was a significant rise in ICP in the intact brain and basic subcompensated intracranial hypertension; no statistically significant change in ICP was observed in decompensated intracranial hypertension. The safe PEEP with regard to CPP was determined by the severity of basic intracranial distention (it was 15 cm H2O in the intact brain and 10 cm H2O in subcompensated hypertension); PEEP exerted no significant effect on CPP in decompensated intracranial hypertension. Conclusion. The effect of PEEP on CPP is determined by not only the value of PEEP, but also by the severity of brain damage. Key words: positive end-expiratory pressure, intracranial pressure, cerebral perfusion pressure.Цель исследования — оценка эффекта положительного давления в конце выдоха (ПДКВ) на церебральное перфузи-онное давление (ЦПД) при внутричерепной гипертензии в эксперименте на биологической модели. Материал и методы. Эксперимент проведен на 10-и свиньях в возрасте 2-х месяцев, массой 17—20 кг. Экспериментальным животным проводили анестезию. Мониторировали следующие параметры: инвазивное артериальное и центральное венозное давление, внутричерепное давление (ВЧД), пиковое инспираторное давление. Моделирование внутричерепной гипертензии проводили с помощью установленного субдурально баллона. При проведении ИВЛ градуировано повышали ПДКВ до 5, 10, 15 и 20 см вод. ст. Результаты. Повышение ПДКВ при проведении ИВЛ сопровождалось прогрессивным ростом внутригрудного давления и снижением среднего артериального давления. При повышении ПДКВ отмечался достоверный рост ВЧД при «интактном» головном мозге и при «базовой» субкомпенсированной внутричерепной гипертен-зии, при декомпенсированной внутричерепной гипертензии статистически значимого изменения ВЧД не наблюдалось. «Безопасный» уровень ПДКВ в отношении ЦПД определялся тяжестью «базовой» внутричерепной дистензии — при интактном мозге он составил 15 см вод. ст., при субкомпенсированной гипертензии — 10 см вод. ст., при декомпенсиро-ванной внутричерепной гипертензии ПДКВ не оказывало значимого влияния на ЦПД. Заключение. Влияние ПДКВ на ЦПД определяется не только величиной ПДКВ, но и тяжестью поражения головного мозга. Ключевые слова: положительное давление в конце выдоха, внутричерепное давление, церебральное перфузионное давление

New technologies and possibilities of breast cancer staging by the criterion N ex vivo

The study was undertaken to improve breast cancer (BC) staging by the criterion N ex vivo, by applying the up-to-date ultrasound and microsurgical technologies. A LySonix 3000® with PulseSelectTM system was used to expose lymph nodes and vessels. Axillary adipose tissue classically exposed was examined in 70 patients with Stages II-III BC. Lymph vessels and nodes were separated by the sonolipodestruction technique. The findings permit sonolipodestruction to be used for ex vivo total lymph dissection for BC as a method that improves its N-staging. Sonolymphodissection opens up fresh opportunities for studying the anatomic structure of the lymphatic apparatus

Dependency of recrystallization mechanism to the initial grain size

The effect of initial grain size on the recrystallization behavior of a type 304 austenitic stainless steel during and following hot deformation was investigated using hot torsion. The refinement of the initial grain size to 8 μm, compared with an initial grain size of 35 μm, had considerable effects on the dynamic recrystallization (DRX) and post-DRX phenomena. For both DRX and post-DRX, microstructural investigations using electron backscattered diffraction confirmed an interesting transition from conventional (discontinuous) to continuous DRX with a decrease in the initial grain size. Also, there were unexpected effects of initial grain size on DRX and post-DRX grain sizes

NEOLYMPHOGENESIS AND CHEMOKINES’EXPRESSION PROFILE DURING BREAST CANCER

The research of surgical material including a primary breast tumor, lymphatic basins with lymph nodes revealed the fact of neo-lymphatic genesis of breast cancer patients. Evidentiary basis  of the genetic  lymphoid  re-forming  is  made   with  the use  of modern biological technologies. Inflammatory chemokines’ expression profile and  their receptors in newly formed lymph nodes  during breast cancer  were analyzed. The analysis revealed an increase in CCL16, XCR1, CYFIP2, TNFSF14 genes  and  a decrease in CXCL5 and  CXCL12 chemokines’ ligands in newly formed lymph nodes .The data got are of a great scientific importance