Is CHF triggered by the vapor recoil effect?

This paper deals with the triggering mechanism of the boiling crisis, a transition from nucleate to film boiling. We observe the boiling crisis in pool saturated boiling experimentally at nearly critical pressure to take advantage of the slowness of the bubble growth and of the smallness of the Critical Heat Flux (CHF) that defines the transition point. Such experiments require the reduced gravity conditions. Close to the CHF, the slow growth of the individual dry spots and their subsequent fusion on the transparent heater are observed through the latter. As discussed in the paper, these observations are consistent with numerical results obtained with the vapor recoil model of the boiling crisis

Quench cooling under reduced gravity

We report the quench cooling experiments performed with liquid O2 under different levels of gravity simulated with the magnetic gravity compensation. A copper disk is quenched from 270K to 90K. It is found that the cooling time in microgravity is very long in comparison with any other gravity level. This phenomenon is explained by the isolation effect of the gas surrounding the disk. The liquid subcooling is shown to drastically improuve the heat exchange thus reducing the cooling time (about 20 times). The effect of subcooling on the heat transfer is analyzed at different gravity levels. It is shown that such type of experiments cannot be used for the analysis of the critical heat flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is analyzed instead

Droplet evaporation in one-component fluids: Dynamic van der Waals theory

In a one-component fluid, we investigate evaporation of a small axysymmetric liquid droplet in the partial wetting condition on a heated wall at $T\sim 0.9 T_c$. In the dynamic van der Waals theory (Phys. Rev. E {\bf 75}, 036304 (2007)), we take into account the latent heat transport from liquid to gas upon evaporation. Along the gas-liquid interface, the temperature is nearly equal to the equilibrium coexisting temperature away from the substrate, but it rises sharply to the wall temperature close to the substrate. On an isothermal substrate, evaporation takes place mostly on a narrow interface region near the contact line in a late stage, which is a characteristic feature in one-component fluids.Comment: 6 pages, 6 figure

Сombined treatment of squamous-cell anal cancer

Since 1974 chemoradiation scheme proposed by Nigro remains the standard of care for squamous-cell anal cancer in most countries. Improvement of treatment results can be achieved by developing new treatment schemes including different radio- and chemosensitizers.Methods. Results of treatment of 157 T1–4N0–2M0 squamous-cell anal cancer patients, which underwent treatment during 1990–2012 were analyzed. Patients were divided into 3 groups: group A received hyperfractionated radiotherapy (RT) single dose 1.2 Gy bid, total dose 40–44 Gy with 3–5 sessions of local hyperthermia (HT) during treatment; group B had similar RT + HT scheme with addition of chemotherapy (CT) with cisplatin 20 mg/m2 in days 1, 3 weeks 1–4 and bleomycin 15 mg in days 2, 4 weeks 1–4; group C had RT with single dose 2 Gy, same total dose, HT and CT as in group B and additionally received metronidazole 10 g/m2 per rectum in a polymeric composition. Two weeks after 1st treatment stage a second course of RT was carried out 20–24 Gy in 2 Gy fractions in all patient groups.Results. Sphincter-sparing treatment was carried out in 11 (50 %), 71 (80.68 %) and 44 (93.62 %) in groups A, B and C accordingly. Three year overall survival (OS) was 60.0; 82.4; 96.4 %; 3-year disease-free survival (DFS) 36.6; 69.8 and 76.3 % accordingly.Conclusions. In our study combined treatment using radiosensitization allow to improve sphincter preservation rate to 93 %, improve OS and DFS for squamous-cell anal cancer patients

Molecular Dynamics Simulation of Spinodal Decomposition in Three-Dimensional Binary Fluids

Using large-scale molecular dynamics simulations of a two-component Lennard-Jones model in three dimensions, we show that the late-time dynamics of spinodal decomposition in concentrated binary fluids reaches a viscous scaling regime with a growth exponent $n=1$, in agreement with experiments and a theoretical analysis for viscous growth.Comment: 4 pages, 3 figure

Spinodal Decomposition in Binary Gases

We carried out three-dimensional simulations, with about 1.4 million particles, of phase segregation in a low density binary fluid mixture, described mesoscopically by energy and momentum conserving Boltzmann-Vlasov equations. Using a combination of Direct Simulation Monte Carlo(DSMC) for the short range collisions and a version of Particle-In-Cell(PIC) evolution for the smooth long range interaction, we found dynamical scaling after the ratio of the interface thickness(whose shape is described approximately by a hyperbolic tangent profile) to the domain size is less than ~0.1. The scaling length R(t) grows at late times like t^alpha, with alpha=1 for critical quenches and alpha=1/3 for off-critical ones. We also measured the variation of temperature, total particle density and hydrodynamic velocity during the segregation process.Comment: 11 pages, Revtex, 4 Postscript figures, submitted to PR

PHYTOPHARMACOTHERAPY OF THE DiSEASES ON THE BASE OF SYSTEM APPROACH

Institute of General and Experimental Biology SB RAS, Ulan-Ude Baikal Institute for Nature Management SB RAS, Ulan-Ude Buryat State University, Ulan-Ude Irkutsk State Medical Academy of Continuing Education, Irkutsk Traditional Medical Science Technology and Production Corporation of Mongolia, Ulaanbaatar The effect of multicimponent medicinal preparations of plant origin is considered, with the use of system approach and the influence of their biologically active substances on the regulatory centers of living processes control is discussed

Оценка клинической эффективности кардиопротекторной терапии у пациентов с острым инфарктом миокарда

Aim. To evaluate the efficiency of cardioprotective therapy using intravenous metoprolol in combination with a high dose of atorvastatin in the prevention of myocardial remodeling (MR) and heart failure (HF) in patients with acute ST-segment elevation myocardial infarction (STEMI).Material AND methods. A prospective study included 100 STEMI patients who underwent primary percutaneous intervention (PCI). Depending on the regimens of drug cardioprotection, three groups of patients were formed: the first (2014–2015) — 34 patients who received 80 mg atorvastatin as a part of the basic therapy on the first day of STEMI, then 20–40 mg/day for 30 days. The second group (2017–2018) — 34 patients who received atorvastatin 80 mg/day for a month from the onset of STEMI. The third group (2018–2019) — 32 patients who received intravenous metoprolol tartrate (5–15 mg) and atorvastatin 80 mg/day before PCI for a month from the onset of STEMI. On days 1 and 2 of STEMI and one month later, patients were assessed for serum levels of cardiac biomarkers; on the 1st, 7th days and one month later, echocardiographic studies (EchoCG) were performed. At the end of the observation, clinical and imaging outcomes (MR and HF) were assessed, which were compared with the dynamics of biomarkers between the groups of patients.Results. The combined use of atorvastatin 80 mg/day for a month from the onset of STEMI and a single intravenous injection of metoprolol tartrate (5–15 mg) in the acute phase of STEMI before PCI showed the most significant effects in the prevention of the development of structural and functional myocardial disorders and clinically severe heart failure, and also caused the minimal serum activity of cardiomarkers in the third group of patients in comparison with the first and second groups of patients without this drug combination. Also, correlations between biomarkers and echocardiography indicators were established in the third group of patients who received cardioprotective therapy.Conclusion. The combined use of high-dose atorvastatin for a month with a single intravenous injection of metoprolol tartrate in acute STEMI before PCI prevents the formation of MR and clinically significant HF in the post-infarction period. Comprehensive dynamic assessment of cardiac biomarkers and echocardiography parameters within a month after post-STEMI is a highly informative tools for monitoring the efficiency of cardioprotective therapy.Цель. Оценить эффективность кардиопротекторной терапии с использованием внутривенного введения метопролола в сочетании с высокой дозой аторвастатина в профилактике развития ремоделирования миокарда (РМ) и сердечной недостаточности (СН) у больных острым инфарктом миокарда с подъемом сегмента ST (ИМпST).Материал и методы. В проспективное исследование включены 100 пациентов с ИМпST, перенесших первичное чрескожное коронарное вмешательство (ЧКВ). В зависимости от режимов медикаментозной кардиопротекции сформированы три группы больных: первая группа (2014–2015) — 34 пациента, получавших в рамках базисной терапии аторвастатин 80 мг в первые сутки ИМпST, затем 20–40 мг на протяжении 1-го месяца; вторая группа (2017–2018) — 34 пациента, получавших аторвастатин 80 мг/сут на протяжении месяца от начала ИмпST; третья группа (2018–2019) — 32 больных, получавших перед ЧКВ внутривенно тартрат метопролола (5–15 мг) и аторвастатин 80 мг/сут на протяжении месяца от начала ИМпST. На 1-е и 2-е сутки ИМпST и через месяц у больных оценивали сывороточные уровни кардиальных биомаркеров; на 1-е, 7-е сутки и через один месяц выполняли эхокардиографическое исследование (ЭхоКГ). По завершении наблюдения оценивали клинико-инструментальные исходы (РМ и СН), которые сопоставляли с динамикой биомаркеров между группами исследуемых лиц.Результаты. Сочетанное применение аторвастатина 80 мг/сут на протяжении одного месяца от начала ИМпST и однократной внутривенной инъекции тартрата метопролола (5–15 мг) в острой фазе ИМпST перед ЧКВ показало наиболее выраженные эффекты в отношении профилактики развития структурно-функциональных нарушений миокарда и клинически выраженной СН, а также обусловило минимальную сывороточную активность кардиомаркеров в третьей группе лиц в сравнении с первой и второй группами пациентов без этой медикаментозной комбинации. Также установлены корреляции между биомаркерами и показателями ЭхоКГ в третьей группе лиц, получавших кардиопротекторную терапию.Выводы. Сочетанное применение аторвастатина в высокой дозе на протяжении одного месяца с однократной внутривенной инъекцией тартрата метопролола при остром инфаркте миокарда с подъемом сегмента ST перед чрескожным вмешательством предотвращает формирование ремоделирования миокарда и клинически выраженной сердечной недостаточности в постинфарктном периоде. Комплексная динамическая оценка кардиальных биомаркеров и показателей ЭхоКГ в течение месяца после перенесенного ИМпST является высокоинформативным средством контроля за эффективностью кардиопротекторной терапии

Скрининг нутриционного статуса в кардиохирургии

Objective: to compare the informative value of four nutritional screening scales in patients operated on the heart under extracorporeal circulation (EC). Subjects and methods. A prospective cohort study was conducted to examine the results of treatment in 894 adult patients operated on under EC. Nutritional screening was carried out using four scales: Nutritional Risk Screening 2002 (NRS-2002), Malnutrition Universal Screening Tool (MUST), Mini Nutritional Assessment (MNA), and Short Nutritional Assessment Questionnaire (SNAQ). Their nutritional status was assessed by the Subjective Global Assessment (SGA) scale. Mortality and postoperative complications were analyzed. Results. The MUST scale had the highest sensitivity (97.9%) in identifying malnutrition (MN). Univariate analysis of postoperative complications indicated that all the scales had a similar prognostic value: MUST [OR 2 (95% CI, 1.4—2.8); р = 0.0001], SNAQ [OR 1.8 (1.2—2.5); р=0.002], NRS-2002 [OR 1.8 (1.1—3.1); р=0.03], MNA [OR 1.8 (1.3—2.4); р=0.0007] and lower sensitivity (21.2, 23.3, 8.5, and 25.7% for SNAQ, MUST, NRS-2002, and MNA, respectively). However, multivariate analysis along with the commonly known risk factors (age, gender, EC duration) confirmed the prognostic value of the MUST [OR 1.6 (1.1—2.4); р=0.01] and MNA [OR 1.5 (1.1—2.1); р=0.02] scales. Conclusion. The MUST scale is of the most informative value in terms of its sensitivity in detecting MN and of independent prognostic value as to postoperative complications. All the scales have a poor prognostic value regarding the postoperative complications, which determines the urgency of developing a special cardiac screening scale for the nutritional status. Key words: cardiac surgery, nutritional screening, nutritional assessment, malnutrition.Цель исследования — сравнение информативности 4-х шкал скрининга нутриционного статуса (НС) у пациентов, оперированных на сердце в условиях искусственного кровообращения (ИК). Материал и методы. Проспективное когортное исследование результатов лечения 894 взрослых пациентов, оперированных в условиях ИК. Скрининг НС проводился с использованием 4-х шкал: Nutritional Risk Screening 2002 (NRS-2002), Malnutrition Universal Screening Tool (MUST), Mini Nutritional Assessment (MNA), and Short Nutritional Assessment Questionnaire (SNAQ). Оценка НС проводилась с использованием шкалы Subjective Global Assessment (SGA). Проанализированы летальность и послеоперационные осложнения. Результаты. Шкала MUST имела наибольшую чувствительность (97.9%) к выявлению нутриционной недостаточности (НН). При однофакторном анализе послеоперационных осложнений все шкалы обладали схожей прогностической ценностью; MUST [ОШ 2 (1,4—2,8 95%ДИ); р=0,0001], SNAQ [ОШ 1,8 (1,2—2,5); р=0,002], NRS-2002 [ОШ 1,8 (1,1—3,1); р=0,03], MNA [ОШ 1,8 (1,3—2,4); р=0,0007] и низкой чувствительностью (21,2, 23,3, 8,5, 25,7% для SNAQ, MUST, NRS-2002 и MNA соответственно). Однако при проведении многофакторного анализа, наряду с общеизвестными факторами риска (возраст, пол, продолжительность ИК) прогностическая ценность подтверждена только для шкал MUST [ОШ 1,6 (1,1—2,4), р=0,01] и MNA [ОШ 1,5 (1,1—2,1), р=0,02]. Заключение. Шкала MUST является наиболее информативной с позиции чувствительности к выявлению НН и независимой прогностической ценности в отношении послеоперационных осложнений. Все шкалы обладают недостаточной прогностической ценностью по отношению к послеоперационным осложнениям, что определяет актуальность разработки особой, кардио-специфичной шкалы скрининга НС. Ключевые слова. Кардиохирургия, скрининг нутриционного статуса, оценка нутриционного статуса, нутриционная недостаточность

Biology of moderately halophilic aerobic bacteria

The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms