Approximate ab initio calculation of vibrational properties of hydrogenated amorphous silicon with inner voids

We have performed an approximate ab initio calculation of vibrational properties of hydrogenated amorphous silicon (a-Si:H) using a molecular dynamics method. A 216 atom model for pure amorphous silicon (a-Si) has been employed as a starting point for our a-Si:H models with voids that were made by removing a cluster of silicon atoms out of the bulk and terminating the resulting dangling bonds with hydrogens. Our calculation shows that the presence of voids leads to localized low energy (30-50 cm^{-1}) states in the vibrational spectrum of the system. The nature and localization properties of these states are analyzed by various visualization techniques.Comment: 15 pages with 6 PS figures, to appear in PRB in December 199

Antibodies directed to antigens secreted by murine epithelioid macrophages modulate BCG-induced granulomata

The authors have previously shown that epithelioid cells isolated from mice secrete a factor, called macrophage deactivating factor (MDF), that promptly deactivates superoxide release by activated macrophages and neutrophils. In this paper some biological properties of a polyclonal rat antiserum directed to MDF and other substances secreted by these cells are described. The immunoglobulin fraction of this antiserum reacted, by immunocytochemical methods, with epitopes in the cell membrane of macrophages adherent to coverslips subcutaneously implanted for 14 days; but not for 5 days. It also reacted with antigens within and outside cells in BCG-induced granulomas. This antiserum blocked completely the macrophage deactivating activity of epithelioid cell culture supernatants. Anti-IL-10 monoclonal antibody, did not block MDF activity. The administration of the immunoglobulin fraction from immunized rats to C5 deficient mice bearing BCG-induced granulomatas in the footpad, significantly reduced the size of the lesions. A marked necrosis of inflammatory cells and mononuclear cells phagocyting debris of necrotic cells were observed in these lesions

Atrial remodelling comparison after maze-3 and cryo-maze procedures in combined cardiac interventions: a retrospective study

Background. The maze procedure aims to eliminate atrial fibrillation (AF), restore sinus rhythm (SR) and atrial contractility. However, conflicting evidence exists regarding the extent of atrial remodelling in various techniques, which directed the focus of our study.Objectives. An atrial remodelling comparison after a cut-and-sew maze-3 surgery and its biatrial cryo-maze modification using 2D echocardiography.Methods. The study is a retrospective uncontrolled interrupted two-cohort time-series trial, with patients selected by pseudorandomisation according to a normal sinus rhythm-maintaining AF surgery method. A total of 217 maze-3 and 113 cryo-maze combined cardiac interventions have been performed within 2012–2021. The interventions included valve repair, coronary artery bypass grafting and their combination. Due to differences in long-term follow-up, the cohorts were pseudorandomised to select by 50 restored vs. maintained sinus rhythm patients using a nearest-neighbour classifier coupled with logistic regression. Mean follow-up period was 6 (1–17) months. The patients had paroxysmal, persistent and longstanding persistent AF. Echocardiography values prior to and long-term post-surgery were further analysed to determine the atrial remodelling dynamics. Results. A statistically significant atrial volume reduction is evident in a long-term within-cohort comparison. Meanwhile, a statistically more pronounced remodelling is observed between cohorts after maze-3 procedure. The cohort 1 vs. 2 estimates are: mean left atrial volume 120/125 mL3 (p = 0.011), left atrial size in apical view 52/53 mm (p = 0.023), right atrial size in apical view 58/62 mm (p = 0.004), right atrial size in parasternal short axis view 43/45 mm (p = 0.004), right atrial area in apical 4-chamber view 25/28 cm2 (p = 0.007). Maintained atrial pacing patients had positive systolic atrial function recovery rates (E/A ratio increased to average 1.5) in the long-term in both comparison cohorts.Conclusion. Remodelling is biatrial after all the maze procedures compared. A more pronounced atrial volume reduction occurs after maze-3 surgery. The presence of sinus rhythm is facilitated by cardiac conduction leading to mechanical and electrical remodelling of the atria

СЕРДЕЧНАЯ РЕСИНХРОНИЗИРУЮЩАЯ ТЕРАПИЯ. ФОРМИРОВАНИЕ ПОКАЗАНИЙ И СОВРЕМЕННЫЕ ПОДХОДЫ К ПОВЫШЕНИЮ ЭФФЕКТИВНОСТИ МЕТОДА

The article provides new insights to cardiac resynchronization therapy (CRT), a method of treating chronic heart failure with cardiac biventricular pacing. The article covers the history of its development starting with the first attempts to eliminate heart dyssynchrony up to the present advances. Over the last decades, CRT has significantly improved, including both implantable devices and electrodes, and current CRT guidelines and indications. The article discusses serial changes in indications and selection criteria for patients based on the results of the recent clinical trials assessing its effectiveness. Evidence-based knowledge is presented for the CRT application in the routine clinical practice. Novel approaches and technologies aimed at improving the effectiveness of CRT are presented.Статья посвящена сердечной ресинхронизирующей терапии (СРТ) – методу лечения хронической сердечной недостаточности посредством бивентрикулярной кардиостимуляции. В статье рассматривается история развития метода от первых попыток устранения диссинхронии сердца до настоящего времени. За последние 20 лет метод претерпел существенное изменение как в плане технического совершенствования имплантируемых устройств и электродов, так и в плане формирования современных показаний к его применению. В статье изучается динамика изменений показаний и критериев отбора пациентов на основе результатов клинических исследований по изучению эффективности метода. Приводятся современные показания для применения СРТ и существующая доказательная база, лежащая в их основе. Описываются современные подходы и технологии, направленные на повышение эффективности метода СРТ

Response to Uzi Rubin’s “Comments on the UCS Report on Countermeasures”

We recently received—via a third party—a critique of our report, Countermeasures. The critique, written by Uzi Rubin and titled “Comments on the UCS Report on Countermeasures,” is dated 18 July 2000. Rubin states that his study was “considerably less exhaustive” than the countermeasures report and was done by “a small team of experienced missile engineers.” Rubin’s critique has not been published, but instead has been distributed informally in the United States. Here we respond to Rubin’s points in the order that he makes them. As we will make clear, Rubin’s criticisms are either technically invalid or based on incorrect characterizations of the assumptions that underlay our work

Оценка сократимости и ремоделирования предсердий после процедуры «Лабиринт-3» при сочетанных вмешательствах на сердце

Highlights. The most important goal of atrial fibrillation surgical treatment is to eliminate the arrhythmia in order to restore atrial contractility and improve their transport function. Our study showed positive dynamics of atrial contractility and remodeling after the maze-3 procedure against the background of a regular heart rhythm restoration. The study of sinus rhythm predictors maintenance and recovery of atrial transport function will help to make patient selection more personified.Aim. Evaluation of atrial contractility and remodeling after the maze-3 procedure with combined interventions on the heart.Methods. The analysis of 217 combined surgical interventions was carried out, where a maze-3 was used to treat atrial fibrillation (AF). The operations were performed in our center from 2012 to 2016. Key points of the study: rhythm after surgery and echocardiographic control in the long-term follow-up in order to determine the dynamics of atrial contractility and volumes. The average follow-up period was 47 (1–100) months. 40 (18.4%) patients had paroxysmal, 38 (17.5%) persistent, 139 (64.1%) long-term persistent AF. The mean AF duration before surgery was 27.4 months (1–200 months). The indications for the maze-3 procedure were: ineffectiveness of antiarrhythmic therapy, the need to perform combined cardiac procedures. We used standard statistical research methods with one – and multivariate logistic regression.Results. In the long-term follow-up, sinus rhythm (SR) persists in 79% of patients. In the long-term follow-up, in this group of patients, the left atrial contractility was  restored  from  76%  to  91%,  while  the  biatrial  contractility  increased from 82 to 96%. Shorter AF duration before surgery was a positive predictor of SR recovery and atrial contractility (p = 0.005), while pulmonary artery pressure and patient age negatively affected these indicators (p = 0.041 and p = 0.038, respectively). The presence of SR early after surgery was not a significant predictor of AF freedom. At the same time, according to the long-term observations, patients maintaining a regular atrial heart rate had positive indicators of atrial systolic function restoration and a positive dynamics of a decrease in atrial volumes.Conclusion. SR and restoration of left atrial contractility are two interrelated goals of the maze procedure. The negative factors associated with the failure of surgical treatment of AF are increased pressure in the pulmonary artery, long-term AF before surgery, and the age of patients.Основные положения. Наиболее важная цель хирургического лечения фибрилляции предсердий – устранение аритмии для восстановления сократимости предсердий и улучшения их транспортной функции. В исследовании показана положительная динамика сократимости и ремоделирования предсердий после процедуры «Лабиринт-3» на фоне восстановления регулярного ритма сердца. Изучение предикторов удерживания синусового ритма и восстановления транспортной функции предсердий способствует более персонифицированному отбору пациентов.Цель. Оценка сократимости и ремоделирования предсердий после процедуры «Лабиринт-3» при сочетанных вмешательствах на сердце.Материалы и методы. Проведен ретроспективный анализ 217 сочетанных хирургических операций, при которых для лечения фибрилляции предсердий (ФП) применена техника «Лабиринт-3». Процедуры выполнены в ФГБУ «ФЦВМТ» Минздрава России (г. Калининград) с 2012 по 2016 г. Ключевые точки исследования: ритм сердца после операции и эхокардиографический контроль в отдаленные сроки наблюдения с целью определения динамики сократимости и объемов предсердий по ЭхоКГ-показателям. Средний период наблюдения составил 47 (1–100) мес. Мужчин – 145 (63%), средний возраст – 65 (45–82) лет. 40 (18,4%) пациентов имели пароксизмальную, 38 (17,5%) – персистирующую, 139 (64,1%) – длительно персистирующую форму ФП. Средняя продолжительность ФП до операции составила 27,4 (1–200) мес. Показаниями для выполнения процедуры «Лабиринт-3» являлись неэффективность антиаритмической терапии, необходимость сочетанных процедур на сердце. Применяли стандартные статистические методы исследования с проведением одно- и многофакторной логистической регрессии.Результаты. В отдаленные сроки наблюдения синусовый ритм сохранялся у 79% пациентов. Также у этой группы больных зарегистрировано восстановление сократимости левого предсердия с 76 до 91%, в то время как биатриальная сократимость увеличилась с 82 до 96%. Меньшая длительность ФП до операции являлась положительным предиктором восстановления СР и сократимости предсердий (р = 0,005), в то время как давление в легочной артерии и возраст пациентов отрицательно влияли на данные показатели (р = 0,041 и р = 0,038, соответственно). Наличие СР в ранние сроки после операции не являлось значимым предиктором свободы от ФП. При этом больные с удерживанием регулярного предсердного ритма сердца, по данным долговременных наблюдений, имели положительные показатели восстановления систолической функции предсердий и динамику уменьшения их объемов.Заключение. Синусовый ритм и восстановление сократимости предсердий – две взаимосвязанные цели процедуры «Лабиринт». Негативными факторами, ведущими к неуспеху хирургического лечения ФП, являются повышенное давление в легочной артерии, длительно существующая ФП до операции и старший возраст пациентов