Diffusion coefficient when fine aerosol media propagate in a confined volume

An experimental estimation is reported of the value of the effective diffusion coefficient during aerosol deposition in a confined volume. Aerosol propagation regularities have experimentally been studied in a chamber of a complex configuration with different placement of aerosol generators

The Structure of Cationic Polyisoprene: Branching versus Cyclization

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimThe structure, molecular weight, and molecular weight distribution (MWD) of polyisoprene fractions, which were obtained during the fraction of polyisoprene with broad MWD (M w/M n = 25.6) synthesized with tBuCl/TiCl4 initiating system have been investigated. It is established that chain transfer to polymer leading to branched macromolecules is responsible for the formation of polyisoprene with broad MWD and reduced unsaturation. It is shown for the first time that unsaturation decreased while the content of head and end groups in a single macromolecule increased with increasing molecular weight of polyisoprene fraction. The unsaturated part of the polymer chain consists of presumably trans-1,4-units independently of the molecular weight of polyisoprene fraction. (Figure presented.)

The role of herpes virus infection in development of arrhythmias in children

ECG' peculiarities and titers of anticardial antibodies (ACAB) were studied in 44 children with herpes virus infection: 63% of patients were infected by herpes virus type IV, V, VI; the rest ones - herpes virus type I,II in addition. ECG has revealed dysfunction of sinus node, conductive disturbances and changes of repolarization in 1/3 of children, 20% of patients has signs of myocardial electric instability. Part of children has increased titers of ACAB to conductive system and cardiomyocytes

Echocardiographic characteristics of COVID-19 pneumonia survivors three months after hospital discharge

Coronavirus disease 2019 (COVID-19) is an infectious disease that affects almost all organs and systems. The main target is the respiratory system, but cardiovascular involvement is also common. Today, it is relevant to study the effect of complicated COVID-19 course on the patient’s cardiovascular system after hospital discharge — in particular, echocardiographic parameters.Aim. To study the echocardiographic parameters of patients with COVID-19 pneumonia 3 months after discharge from the hospital.Material and methods. The study included 106 patients with documented COVID-19 pneumonia. Patients underwent a comprehensive examination during hospitalization and 3 months ± 2 weeks after hospital discharge. The mean age of participants was 47±16 years (from 19 to 84 years), while 49% were women.Results. Three months after discharge, the average body mass index of the subjects was 28,2±5,7 kg/m2. Obesity was noted in 37,1%, cardiovascular diseases — in 52%. According to echocardiography, the prevalence of right ventricular (RV) dilatation was 2,9%, a decrease in tricuspid annular plane systolic excursion (TAPSE) — 9,5%, grade ≥2 tricuspid regurgitation — 1,9%, pulmonary hypertension (pulmonary artery systolic pressure >36 mm Hg) — 3,8%. The mean value of RV global longitudinal myocardial strain (GLMS RV) and global longitudinal myocardial strain (GLES RV) was 19,6±4,5 and 20,6±4,6, respectively. We found moderate correlations between GLMS RV and blood flow time through the left ventricular outflow tract (OT) (r=-0,436), through the mitral valve (r=-0,390; both p<0,0001) and through the RVOT (r=-0,348; р=0,004), with cardiac index (CI) (r=0,316; p=0,009), as well as between GLES RV and blood flow time through the LVOT (r=-0,411; p<0,0001) and RVOT (r=-0,300; p=0,005), and with CI (r=0,302; p=0,004). At the same time, the correlation of GLES RV with RV fractional area change (FAC) was weak (r=-0,283; p=0,007), while there was no correlation with the TAPSE. In addition, correlation of GLMS RV with these parameters were not defined.Conclusion. Three months after COVID-19 pneumonia, RV strain parameters were shown to have stronger relationships with time characteristics of flows in LVOT and RVOT, as well as with CI, than with such generally accepted characteristics of RV function as FAC and TAPSE

Cardiovascular status and echocardiographic changes in survivors of COVID-19 pneumonia three months after hospital discharge

Coronavirus disease 2019 (COVID-19) affects the function of all organs and systems. Today, studying the effect of COVID-19 on cardiovascular system, including on echocardiographic characteristics, is relevant.Aim. To study the prevalence of symptoms, cardiovascular disease and changes in echocardiographic data in persons after documented COVID-19 pneumonia 3 months after discharge from the hospital.Material and methods. The study included 106 patients after documented COVID-19 pneumonia. The patients underwent a comprehensive examination during hospitalization and 3 months±2 weeks after discharge from the hospital. The mean age of participants was 47±16 years (19-84 years); 49% of subjects were women.Results. Three months after hospital discharge, the symptoms persisted in 86% of examined patients. There were significant echocardiographic changes as follows: a decrease in LV end-diastolic, end-systolic and stroke volume (113,8±26,8 ml vs 93,5±29,4 ml; 37,7±13,0 ml vs 31,3±14,2 ml; 77,2±17,8 ml vs 62,2±18,7 ml, respectively, p<0,001 for all). The right ventricular anteroposterior dimension and the pulmonary trunk diameter decreased over time (26,0 [24,0-29,3] mm vs 25,0 [23,0-27,0] mm, p=0,004; 21,7±3,6 mm vs 18,7±2,5 mm, p<0,001), the same as the pulmonary artery systolic pressure, estimated by tricuspid regurgitation gradient (28,0 [25,0-32,25] mm Hg vs 21,5 [17,0-25,0] mm Hg). The right atrial volume (42,0 [37,0-50,0] m><0,001), the same as the pulmonary artery systolic pressure, estimated by tricuspid regurgitation gradient (28,0 [25,0-32,25] mm Hg vs 21,5 [17,0-25,0] mm Hg). The right atrial volume (42,0 [37,0-50,0] ml vs 31,0 [22,0-36,5] ml, p<0,001) a><0,001) and maximum width (36,1±4,6 mm vs 34,5±6,5 mm, p=0,023) decreased, while the right atrial maximum length increased (46,7±6,8 mm vs 48,6±7,1 mm, p=0,021).Conclusion. In survivors of COVID-19 pneumonia three months after hospital discharge, complaints persisted in 86% of cases. Cardiovascular diseases were detected in 52% of participants, including hypertension in 48,1% and coronary artery disease in 15,1%. Compared with in-hospital data, the echocardiographic characteristics improved, which was expressed mainly in a decrease in right heart load

Комбинированное лечение больных раком прямой кишки с использованием программы полирадиомодификации в сочетании с короткими курсами неоадъювантной лучевой терапии

Objective: to improve the outcomes of combination treatment of patients with rectal cancer using polyradiomodification and short courses of neoadjuvant radiotheragy.Materials and methods. A total of 905patients were included into this retrospective study based on the data retrieved from a prospective database. Of them, 241 patients underwent combination treatment with polyradiomodification (CT + PRM); 271 patients underwent combination treatment with preoperative radiotherapy alone (CT); 393patients underwent surgical treatment only (ST). Combination treatment with polyradiomodification included a course of radiotherapy with a total dose of 25 Gy delivered in 5 fractions (5 Gy each), rectal administration of biopolymer composition containing metronidazole at a dose of 10 g/m2 (5-h exposure in the rectum on days 3 and 5), and chemotherapy with capecitabine at a dose of 2 g/m2 on days 1—14 followed by surgery within the next 4—6 weeks. We analyzed the incidence of postoperative complications, 5-year relapse-free survival, and frequency of relapses.Results. The incidence of grade IIIB postoperative complications was significantly lower in patients who underwent combination treatment with polyradiomodification than in those who had surgery only (p = 0.0023) and those who had combination therapy without polyradiomodification (p = 0.0003). The 5-year relapse-free survival rate was 80.5 % in the group of CT + PRM compared to 64.9 % in the group of CT (p = 0.00315) and 60.1 % in the group of ST (p = 0.000001). The frequency of relapses was 0.4 %, 8.5 % (p = 0.00001), and 13.7 % (p = 0.00001) in the groups CT + PRM, CT, and ST respectively. There were no significant differences in the incidence of distant metastasis between the groups.Conclusions. The developed variant of combination treatment with polyradiomodification did not increase the number of complications and ensured better relapse-free survival due to improved locoregional control.Цель исследования — улучшить результаты комбинированного метода лечения больных раком прямой кишки с использованием программы полирадиомодификации в сочетании с короткими курсами неоадъювантной лучевой терапии.Материалы и методы. В ретроспективное исследование, основанное на данных проспективно заполняемой базы данных, включено 905 больных, из которых у 241 проведено комбинированное лечение с применением программы полирадиомодификации, у 271 пациента ранее проведено комбинированное лечение с использованием только предоперационной лучевой терапии в монорежиме, и у 393 — только хирургическое лечение. Комбинированное лечение с применением программы полирадиомодификации включало проведение курса лучевой терапии в разовой очаговой дозе 5 Гр в течение 5 дней до суммарной очаговой дозы 25 Гр, внутриректальной сверхвысокочастотной гипертермии в дни 3 и 5, введение биополимерной композиции, содержащей метронидазол в дозе 10 г/м2, с экспозицией ее в прямой кишке в течение 5 ч в дни 3 и 5, а также проведение химиотерапии капецитабином в дозе 2 г/м2 в дни 1—14 с последующим оперативным вмешательством в сроки от 4 до 6 нед. Анализировали частоту послеоперационных осложнений, 5-летнюю безрецидивную выживаемость, частоту рецидивов.Результаты. Частота послеоперационных осложнений IIIB степени тяжести в группе комбинированного лечения с применением программы полирадиомодификации была ниже по сравнению с группой хирургического лечения (р = 0,0023) и группой комбинированного лечения без применения программы полирадиомодификации (р = 0,0003). Пятилетняя безрецидивная выживаемость в группе комбинированного лечения с применением программы полирадиомодификации составила 80,5 % по сравнению с 64,9 % в группе комбинированного лечения без использования полирадиомодификации (р = 0,00315) и 60,1 % в группе хирургического лечения (р = 0,000001). Частота рецидивов составила 0,4 %, 8,5 % (р = 0,00001) и 13,7 % (р = 0,00001) соответственно. Частота отдаленного метастазирования достоверно не различалась между группами.Выводы. Созданный вариант комбинированного лечения с применением программы полирадиомодификации не приводит к увеличению общего количества осложнений и в рамках проведенного ретроспективного исследования обеспечивает более высокие показатели безрецидивной выживаемости за счет усиления локорегионарного контроля