Generation of small-scale structures in the developed turbulence

The Navier-Stokes equation for incompressible liquid is considered in the limit of infinitely large Reynolds number. It is assumed that the flow instability leads to generation of steady-state large-scale pulsations. The excitation and evolution of the small-scale turbulence is investigated. It is shown that the developed small-scale pulsations are intermittent. The maximal amplitude of the vorticity fluctuations is reached along the vortex filaments. Basing on the obtained solution, the pair correlation function in the limit $r\to 0$ is calculated. It is shown that the function obeys the Kolmogorov law $r^{2/3}$.Comment: 18 page

Определение полисорбата 80 в биофармацевтических препаратах с помощью оптимизированной колориметрической методики

Objectives. We hereby describe an improvement of a previously developed quantification technique for polysorbate 80 in biopharmaceutical formulations (darbepoetin alfa and eculizumab) and report the validation of the new approach.Methods. Polysorbate was isolated from analyte samples by protein precipitation using an organic solvent, followed by supernatant evaporation in vacuum. Polysorbate was derivatized using a ferric thiocyanate reagent and extracted into an organic phase; the relevant optical density measurements were performed.Results. We established the optimal conditions for each step of the analysis procedure. The accuracy was 97–102% in the tested analytical range, the relative standard deviation did not exceed 5%, and the limit of quantification was 0.01 mg/mL.Conclusions. The reported approach is highly sensitive; polysorbate isolation and quantification do not depend on the matrix or, most importantly, the protein.Цели. В данной работе была усовершенствована ранее разработанная методика определения полисорбата 80 в биотехнологических препаратах (дарбэпоэтин альфа, экулизумаб), а также проведена ее валидация.Методы. Полисорбат извлекали из пробы осаждением белка органическим растворителем, затем выпаривали супернатант в вакууме. Полисорбат дериватизировали оптимизированным железо–тиоцианатным реагентом; дериват экстрагировали в слой органического растворителя и измеряли оптическую плотность.Результаты. Были установлены оптимальные условия для каждой стадии методики. Правильность находится в диапазоне степени извлечения 97–102%, относительное стандартное отклонение составляет не более 5%, предел количественного определения методики 0.01 мг/мл.Выводы. Представленная методика имеет высокую чувствительность. Извлечение и определение полисорбата не зависят от матрикса пробы – прежде всего, от присутствующего белка

Transplantation of solid organs during the pandemic of a new coronavirus infection

The end-stage stage of chronic diseases of solid organs is rather significant in the structure of morbidity and mortality among patients worldwide. To date, there are more than six million patients in this status worldwide. Heart, liver and kidney transplantation is the gold standard of treatment for these patients. The number of transplants is growing every year.At the end of 2019, the world faced a new type of viral infection – SARS-CoV-2 – a highly contagious systemic respiratory disease transmitted by airborne droplets, which in three months led to a pandemic and killed hundreds of thousands of people. The pandemic has made adjustments to the structure of planned medical care. The number of planned operations has decreased significantly, and the number of the infection-associated complications has increased.Patients with end-stage chronic diseases initially have weakened immunity and represent the category most susceptible to the infection. At the moment, the question of patient management tactics remains open. There is no consensus on the patient management tactics before surgery and in the posttransplantation period for patients at the end-stage chronic disease of different organs. This topic requires further study and the development of treatment algorithms for such patients

Comparison of REMS, NEWS, qSOFA and SIRS criteria scales for sepsis prediction in patients with diagnosis “SARS-CoV-2, virus unidentified”: a retrospective observational study

Background. Despite ample research on the coronavirus infection sequence and therapy, the incidence of adverse outcomes remains very high. Sepsis stands among the major factors greatly complicating treatment and increasing the risk of death. A timely identification of highrisk sepsis patients is a cornerstone of effective sepsis prevention.Objectives. A comparative prognostic power assessment between the quick Sequential Organ Failure Assessment (qSOFA) scale, National Early Warning Score (NEWS), Initial Prehospital Rapid Emergency Medicine Score (REMS) and the Systemic Inflammatory Response Syndrome (SIRS) criteria for sepsis detection in anaesthetic intensive care patients with a diagnosis: SARS-CoV-2, virus unidentified.Methods. A retrospective observational study included 166 patients over 18-year age with unconfirmed infection (ICD-10 code U07.2). The qSOFA, NEWS, REMS and SIRS point estimates were obtained from each patient. The patients were retrospectively divided in two cohorts by sepsis presence (Sepsis-3 criteria) to determine the express scales power in evaluating the risk of sepsis (estimated as area under ROC curve, AUROC).Results. Data on 102 patients were included in the final analysis. Fifty-eight (57%) patients were terminal, and 55 (54%) developed sepsis. The estimates are as follows: NEWS — AUROC 0.848 [95% confidence interval (CI) 0.764–0.912], sensitivity 76.36% [95% CI 63.0–86.8], specificity 82.98% [95% CI 69.2–92.4], optimal cut-off threshold >5 points; qSOFA — AUROC 0.700 [95% CI 0.602–0.787], sensitivity 76.36% [95% CI 63.0–86.8], specificity 61.70% [95% CI 46.4–75.5], optimal cut-off threshold >0 points; REMS — AUROC 0.739 [95% CI 0.643–0.821], sensitivity 69.09% [95% CI 55.2–80.9], specificity 65.96% [95% CI 50.7–79.1], optimal cut-off threshold >5 points; SIRS criteria — AUROC 0.723 [95% CI 0.626–0.807], sensitivity 98.18% [95% CI 90.3–100.0], specificity 31.91% [95% CI 19.1–47.1], optimal cut-off threshold >0 points.Conclusion. The NEWS scale revealed a good prognostic power to estimate the risk of sepsis in patients with suspected COVID-19 disease. The qSOFA, REMS scales and SIRS criteria possess a good calibration capacity, albeit insufficient resolution, which limits their prognostic value

Методика ВЭЖХ для определения полисорбата 80 в препаратах рекомбинантных терапевтических белков

Objectives. Polysorbate 80 (PS80) quantification in biopharmaceutical products has always been challenging owing to its minute content, absorption to the protein backbone, lack of specific chromophoric PS80 groups, and heterogenic nature. This work is aimed at developing an express method for PS80 analysis in biopharmaceutical products using hydrolysis and subsequent highperformance liquid chromatography analysis with ultraviolet detection that does not consume substantial amounts of sample (≥35 μL).Methods. Five therapeutic protein formulations were chosen as model proteins. Alkaline hydrolysis formulation was applied, without protein precipitation and with a range of precipitation techniques to remove protein from the test solution and hydrolyze PS80, to free fatty acids. The obtained hydrolysate was analyzed using reverse-phase high-performance liquid chromatography.Results. As a result of the high protein content of monoclonal antibody formulations, preliminary protein removal was required, which was achieved by precipitation with organic solvents. A specific precipitant ethanol–isopropanol mixture (1:1 volumetric ratio) was developed to efficiently remove antibodies while keeping PS80 in the solution. The PS80 quantification method was developed for monoclonal antibody drugs. For three monoclonal antibody drug products (adalimumab, infliximab, and eculizumab), method validation was performed according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use, the United States Pharmacopeia, and the State Pharmacopeia of the Russian Federation guidelines.Conclusions. The optimal assay conditions for each group of recombinant monoclonal antibody substances were chosen. Protein precipitation with ethanol or ethanol–isopropanol mixtures before hydrolysis was introduced, allowing for a substantial reduction of sample to 35 μL or even less if PS80 content is higher than 0.05 mg/mL. Accelerated hydrolysis (90 min) is preferable to slow hydrolysis (4–18 h). Method validation for protein products such as adalimumab, infliximab, and eculizumab was demonstrated for the first time. Both methods were validated for each drug product. The coefficients of variation for method specificity and high precision were ≤6.0% for 3 analyses. The accuracy of the methods ranged from 96% to 109% for all of the tested drug products.Цели. Определение полисорбата 80 в препаратах терапевтических рекомбинантных белков всегда являлось трудной задачей, ввиду низкого содержания, гетерогенной природы, присутствия белка в препарате, а также отсутствия хромофорных групп у данного аналита. Целью данной работы являлась разработка экспрессной и экономичной методики определения полисорбата 80 в препаратах рекомбинантных моноклональных антител с использованием гидролиза с последующим определением высвобожденной олеиновой кислоты методом высокоэффективной жидкостной хроматографии (ВЭЖХ) с УФ детектированием.Методы. В качестве модельных образцов выбраны пять терапевтических рекомбинантных белков. Использован щелочной гидролиз без удаления белка и с его удалением различными способами осаждения для выделения свободных жирных кислот. Полученный гидролизат проанализирован методом ВЭЖХ.Результаты. Для субстанций моноклональных антител, ввиду высокого содержания белка, требовалось его удаление. В качестве наиболее простого способа удаления выбрана денатурация и последующая преципитация белка, что достигалось путем осаждения антитела органическим растворителем. Был выбран универсальный осадитель (смесь этанола и изопропанола в объемном соотношении 1:1), использование которого позволяло эффективно удалять моноклональное антитело, но в то же время не допускать потерь полисорбата 80. Была разработана экспрессная методика определения полисорбата 80 для субстанций моноклональных антител. Методика определения полисорбата 80 валидирована согласно требованиям International Council for Harmonisation, United States Pharmacopeia и Государственной фармакопеи Российской Федерации.Выводы. Были проведены испытания условий пробоподготовки для моноклональных антител. Впервые было внедрено осаждение белка этанолом или смесью этанол-изопропанол перед проведением гидролиза и анализом полисорбата 80. Это позволило значительно уменьшить требуемое количество образца для анализа – до 35 мкл, при концентрации полисорбата 80 – 0.05 мг/мл или еще меньше при его большем содержании. Ускоренный гидролиз полисорбата 80 в течение 90 мин является более предпочтительным при проведении анализа в сравнении с продолжительным гидролизом в течение 4–18 ч, описанным в литературе. Впервые была проведена валидация методики пробоподготовки и анализа для моноклональных антител адалимумаб, экулизумаб и инфликсимаб. Высокая прецизионность методики (среднеквадратичное отклонение ≤6.0%), специфичность и удовлетворительные значения правильности (фактор отклика от 96 до 109%), говорят о пригодности методики для определения полисорбата 80 в лекарственных средствах на основе рекомбинантных моноклональных антител

Small-scale clumps in the galactic halo and dark matter annihilation

Production of small-scale DM clumps is studied in the standard cosmological scenario with an inflation-produced primeval fluctuation spectrum. Special attention is given to three following problems: (i) The mass spectrum of small-scale clumps with $M \lesssim 10^3 M_{\odot}$ is calculated with tidal destruction of the clumps taken into account within the hierarchical model of clump structure. Only 0.1 - 0.5% of small clumps survive the stage of tidal destruction in each logarithmic mass interval $\Delta\ln M\sim1$. (ii) The mass distribution of clumps has a cutoff at $M_{\rm min}$ due to diffusion of DM particles out of a fluctuation and free streaming at later stage. $M_{\rm min}$ is a model dependent quantity. In the case the neutralino, considered as a pure bino, is a DM particle, $M_{\rm min} \sim 10^{-8} M_{\odot}$. (iii) The evolution of density profile in a DM clump does not result in the singularity because of formation of the core under influence of tidal interaction. The radius of the core is $R_c \sim 0.1 R$, where $R$ is radius of the clump. The applications for annihilation of DM particles in the Galactic halo are studied. The number density of clumps as a function of their mass, radius and distance to the Galactic center is presented. The enhancement of annihilation signal due to clumpiness, valid for arbitrary DM particles, is calculated. In spite of small survival probability, the annihilation signal in most cases is dominated by clumps. For observationally preferable value of index or primeval fluctuation spectrum $n_p \approx 1$, the enhancement of annihilation signal is described by factor 2 - 5 for different density profiles in a clump.Comment: inor changes in text and 2 references adde

Гендерное сравнение непосредственных и среднесрочных результатов операции Озаки: анализ Propensity Score Matching

Highlights. A retrospective analysis of the patients’ data after Ozaki operation in four Russian Medical Centers was carried out. A comparative gender assessment of the immediate and medium-term results of Ozaki operation was performed.Aim. Gender assessment of Ozaki operation immediate and mid-term results in patients with aortic valve (AV) pathology.Methods. A retrospective multicenter study enrolled 251 patients (135 women, median age 66 (60–70) years old) who underwent Ozaki operation (2017–2020) was carried out in four centers in Russia. After propensity score matching, 92 patients were selected (mean age 65.8±10.8 years old). Two groups were formed in the gender structure: 46 females (average age 67.8±6.3 years old), 46 males (average age 63.8±15.4 years old). The main cause of AV dysfunction was severe aortic stenosis – in 86 (93.5%) cases. Chronic heart failure of III–IV functional class according to NYHA was observed in 26 (28.3%) patients. A bicuspid AV was in 24 cases (26.1%). The primary endpoint was hospital mortality. Postoperative complications and mid-term results (three-year overall survival and freedom from reoperation on AV) were assessed as secondary endpoints; the median follow-up period was 23 (18–33) months.Results. There was no statistically significant difference between the groups in the duration of surgery (275 minutes for females and 285 minutes for males, p = 0.4), cardiopulmonary bypass (98 minutes for females and 115 minutes for males, p = 0.3), aortic clamping (80 minutes for females and 93 minutes for males, p = 0.7). Hospital mortality among the studied patients did not differ: in the female group – 2.2% (1 case) and 0 in the male one, p = 0.9. There were no significant differences in postoperative complications: sepsis (2.2% in women and 0 in men, p = 0.9), superficial wound infection (8.7% in women and 6.5% in men, p = 0.9). Acute kidney injury, stroke, pacemaker implantation, resternotomy for bleeding were not observed in any patient. Three-year overall survival was 91.8% in females and 91.6% in males, p = 0.8; three-year freedom from reoperation – 94.4% for females and 100% for males, p = 0.1.Conclusion. Ozaki operation is equally reproducible with the same hospital mortality, postoperative complications, and medium-term outcomes in both females and males.Основные положения. Проведен ретроспективный анализ данных больных, перенесших операцию Озаки в четырех медицинских центрах России. • Выполнена сравнительная гендерная оценка непосредственных и среднесрочных результатов операции Озаки.Цель. Гендерная оценка непосредственных и среднесрочных результатов операции Озаки у пациентов с патологией аортального клапана (АК).Материалы и методы. Проведено ретроспективное многоцентровое исследование 251 больного (135 женщин, медиана возраста 66 (60–70) лет), которым выполнена операция Озаки (2017–2020 гг.) в четырех медицинских центрах России. После псевдорандомизации (propensity score matching) отобраны 92 пациента (средний возраст 65,8±10,8 года). В зависимости от гендерной принадлежности сформированы две группы: 46 женщин (средний возраст 67,8±6,3 года), 46 мужчин (средний возраст 63,8±15,4 года). Основной причиной дисфункции АК был тяжелый аортальный стеноз – 86 (93,5%) случаев. Хроническая сердечная недостаточность III–IV функционального класса по NYHA отмечена у 26 (28,3%) больных. В 24 случаях (26,1%) АК был двустворчатый. Первичной конечной точкой являлась госпитальная летальность. В качестве вторичных конечных точек оценивали послеоперационные осложнения и среднесрочные результаты (трехлетняя общая выживаемость и свобода от реоперации на АК), медиана периода наблюдения составила 23 (18–33) мес.Результаты. Не получено статистически значимой разницы между группами по длительности операции (275 мин у женщин и 285 мин у мужчин, p = 0,4), искусственного кровообращения (98 и 115 мин, p = 0,3), пережатия аорты (80 и 93 мин соответственно, p = 0,7). Госпитальная летальность среди исследуемых больных не различалась: в женской группе – 1 случай (2,2%), в мужской – 0, p = 0,9. По послеоперационным осложнениям значимых различий не зарегистрировано: сепсис (2,2% у женщин и 0 у мужчин, p = 0,9), раневая поверхностная инфекция (8,7 и 6,5% соответственно, p = 0,9). Острого повреждения почек, инсульта, имплантации постоянного электрокардиостимулятора, рестернотомии по поводу кровотечения не выявлено ни у одного пациента. Трехлетняя общая выживаемость составила 91,8% у женщин и 91,6% у мужчин, p = 0,8; трехлетняя свобода от реоперации – 94,4 и 100% соответственно, p = 0,1.Заключение Операция Озаки воспроизводима у мужчин и женщин с одинаковыми госпитальной летальностью, послеоперационными осложнениями и среднесрочными результатами.