FIELDS EXCITED AND PROVIDING A UNIFORM FOCUSING OF SHORT RELATIVISTIC ELECTRON BUNCHES IN PLASMA

Plasma wake lens in which all short relativistic electron bunches of sequence are focused identically and uniformly is studied analytically and by numerical simulation. For two types of lenses necessary for these parameters of focused sequence of relativistic electron bunches are formulated. Verification of these parameters is performed by numerical simulation

TRANSFORMATION RATIO AT PLASMA WAKEFIELD EXCITATION BY LONG ELECTRON BUNCH WITH SHAPING OF ITS CHARGE ACCORDING COSINE

Possibility of increase of the transformation ratio at plasma wakefield excitation by long relativistic electron bunch, which charge is shaped according to cosine, with purpose to provide the absence of oscillating (on length of bunch) decelerating wakefield, usually attainable, using bunch - precursor, is considered. Length of bunch is selected more larger than wavelength. It is shown analytically that at the choice of charge shaping of long bunch according to cosine distribution one can do without a bunch – precursor to eliminate oscillating decelerating wakefield. Thus the transformation ratio is just in one and a half times less than in the case with a precursor

Uveal melanoma dissemination within the scleral tract in fine needle aspiration biopsy

Introduction. Fine needle aspiration biopsy (FNAB) of uveal melanoma (UM) is an invasive procedure. Many authors consider UM FNAB to be safe procedure, however extraocular extension of the tumor through the scleral tracts may occur. Current studies of scleral tracts after FNAB do not compare different biopsy techniques (cannula-assisted and without cannula) in terms of UM cells.Purpose. To assess morphology of scleral tracts for the presence of malignant cells when different biopsy techniques are approached.Material and methods. Forty-four scleral samples were analyzed after transvitreal FNAB performed in 22 enucleated eyes with UM. Cannula-assisted FNAB was performed in 22 cases. In the same eyes FNAB (n=22) was performed without cannula.Results. FNAB material was adequate for cytological examination in all cases. UM was confirmed in 22 eyes pathologically. UM cell implantation was detected in 5 scleral samples after FNAB without cannula. No signs of cell implantation were seen after cannula-assisted FNAB. The risk of scleral tract UM cell implantation was statistically lower in cannula-assisted FNAB technique (p=0.018, Pearson Chi-square test).Conclusions. UM FNAB performed directly through the sclera without cannula is associated with tumor cells implantation in scleral tract. Cannula-assisted FNAB significantly reduces the incidence of UM implantation in scleral tract

The Hitting Times with Taboo for a Random Walk on an Integer Lattice

For a symmetric, homogeneous and irreducible random walk on d-dimensional integer lattice Z^d, having zero mean and a finite variance of jumps, we study the passage times (with possible infinite values) determined by the starting point x, the hitting state y and the taboo state z. We find the probability that these passages times are finite and analyze the tails of their cumulative distribution functions. In particular, it turns out that for the random walk on Z^d, except for a simple (nearest neighbor) random walk on Z, the order of the tail decrease is specified by dimension d only. In contrast, for a simple random walk on Z, the asymptotic properties of hitting times with taboo essentially depend on the mutual location of the points x, y and z. These problems originated in our recent study of branching random walk on Z^d with a single source of branching

Coronacrisis: threats and opportunities for the financial market

The results of a scientific study of various areas of the financial market (such as credit market, insurance market, investment market, currency market, stocks and bonds market), aimed at studying the potential opportunities and threats from a pandemic COVID-19 are presented. In the work qualitative analysis of financial events in 2020 were used, the opinions of experts were analyzed, and statistical data was interpreted. Main conclusion: there is a reduction in production activity around the world which caused a decline in oil prices, led to a sharp decline in stock prices in major markets and the fact that bond yields began to decrease

Ovarian reserve and autoimmune thyroid diseases

Present literature review provides information about clinical trials that evaluated the association of the carriage of antithyroid antibodies (ATA) and the reduction of the ovarian reserve, as well as the effectiveness of assisted reproductive technologies. The ambiguity and sometimes the opposite of the conclusions of different authors, makes it possible to recommend a balanced attitude to the advisability of screening for ATA in women with a reproductive dysfunction as well as the therapeutic measures proposed in some guidelines based on the results of such examination

Assessment of the clinical status and behavioral risk factors in patients with cardiovascular and other noncommunicable diseases in Russia and neighboring countries during quarantine and self-isolation

Aim. To carry out a comparative assessment of the clinical status and behavioral risk factors in patients with cardiovascular (CVD) and other noncommunicable diseases (NCDs) in Russia and neighboring countries during quarantine and selfisolation in the context of coronavirus disease 2019 (COVID-19) pandemic.Material and methods. The study involved patients from Russia, Azerbaijan, Kazakhstan, Lithuania, Kyrgyzstan. A total of 351 men and women aged 30- 69 years with one or more NCDs were included, including hypertension (HTN), coronary artery disease with or without myocardial infarction, type 2 diabetes, chronic obstructive pulmonary disease/ asthma, and cancer that were in quarantine self-isolation. To assess the clinical status and risk factors, patients underwent a questionnaire and examination. The changes in health status was assessed using the EQ-5D questionnaire.Results. During self-isolation and quarantine, 40% of patients noted a decrease and limitation of physical activity. An increase in food frequency and amount was registered in 35% of individuals. During quarantine, every third patient with HTN had hypertensive crises, and every fifth increased the doses of the drugs taken. In the examined cohort, exertional angina (30%) took second place among NCDs. In the group of Azerbaijan patients, every second had exertional angina, while in the Russian cohort — 33%, and in the Lithuanian group — every fourth patient. In general, health status deterioration among people with angina was noted in 6% of cases. In the examined group, type 2 diabetes was detected in 25% of cases. During quarantine, changes in hypoglycemic therapy were carried out in an average of 34% of patients. COVID-19 was registered in 22% of patients in the examined cohort. The largest number was found in the group from Kazakhstan — 57%, while the second place was taken by the Azerbaijan group — 40%. General condition deterioration was detected in 55% of cases in groups from Azerbaijan and Kazakhstan. In Russia, this was reported by 28,8% of patients, while in the group from Lithuania, every fourth patient noted a worsening of the health status. The lowest deterioration was registered in the Kyrgyzstan group (14%).Conclusion. During quarantine and self-isolation among patients with NCDs, a decrease in physical activity, an increase in food consumption and smoking was noted. There was health status deterioration in patients with various NCDs, primarily with CVDs, which required therapy changes. Taken together, this was reflected in general condition worsening in patients with chronic NCDs. It is obvious that the development of comprehensive preventive measures in conditions of selfisolation and quarantine is required

Оценка риска метастазирования при проведении «прогностической» тонкоигольной аспирационной биопсии увеальной меланомы

Despite the widespread u se of fine-needle aspiration biopsy (FNAB) of uveal melanoma (UM) for prognostic purposes, there are still doubts about the safety of this procedure. No analysis of such data can be found in domestic literature, and foreign authors have published only a few papers on this issue.The purpose of this study is to analyze the risk of metastasis in patients with UM during FNAB.Two groups of patients were formed: the main group, where FNAB was performed during brachytherapy (BT) (BT + FNAB) (n = 70), and the control group, where only BT was performed (n = 144).According to the obtained data, the probability of metastases during a 3‑year follow-up period did not significantly differ between the two groups (p = 0.22 by Fisher's exact test and p = 0.11 by log-rank test when assessing survival using the Kaplan – Meier method), the relative risk (RR) was 1.43 [95 % CI 0.79 to 2.24]. In addition, there was no significant difference in the main clinical outcomes of local treatment associated with worse prognosis: the degree of tumor regression (p = 0.46), extrascleral growth, the need for additional brachytherapy (p = 0.32) or secondary enucleation (p = 0.99).The absence of a significant difference in patient survival between the BT and BT + FNAB groups opens up prospects for a more extensive use of FNAB in patients with UM for prognostic purposes.Аннотация: Несмотря на широкое использование тонкоигольной аспирационной биопсии (ТИАБ) увеальной меланомы (УМ) с прогностической целью, до сих пор высказываются сомнения в безопасности этой процедуры. При этом в отечественной литературе анализ таких данных не проводился, а среди зарубежных авторов по этой теме встречаются лишь единичные работы.Цель: проведение анализа риска метастазирования у пациентов с УМ при проведении ТИАБ.Были сформированы 2 группы пациентов: основная, где при проведении брахитерапии (БТ) одномоментно выполняли ТИАБ (БТ + ТИАБ) (n = 70), и контрольная, где проводилась только БТ (n = 144).Согласно полученным данным, вероятность возникновения метастазов в период 3‑летнего наблюдения в обеих группах не имеет статистически значимой разницы (p = 0,22 по точному критерию Фишера и p = 0,11 по логарифмическому ранговому критерию при оценке выживаемости методом Каплана – Майера), относительный риск (RR) составил 1,43 (95 % доверительный интервал от 0,79 до 2,24). Кроме того, не отмечалось статистически значимой разницы при оценке основных клинических исходов локального лечения, ассоциированных с ухудшением прогноза: степень регрессии опухоли (p = 0,46), экстрасклеральный рост, необходимость проведения дополнительной брахитерапии (p = 0,32) или вторичной энуклеации (p = 0,99).Отсутствие статистически значимой разницы в выживаемости пациентов в группах БТ и БТ + ТИАБ открывает перспективы для более масштабного применения ТИАБ у пациентов с УМ с прогностической целью

Анализ потребности пациентов с увеальной меланомой в индивидуальном прогнозировании риска метастазирования

Molecular-genetic study of uveal melanoma (UM) is crucial in predicting the risk of metastasis of this tumor. Such analysis is also possible during organ-sparing treatment based on fine-needle aspiration biopsy (FNAB), however, not all patients may consider this study appropriate and/or accessible.The goal of this study was to analyze the needs of patients with UM for individual metastasis risk prognosis.This retrospective cohort study was conducted using a questionnaire in 94 patients with UM (mean age 60 ± 13 years; 69 % women and 31 % men). Despite the rather high proportion of interested patients (77 %), only half (51 %) of them ultimately agreed to undergo a ”prognostic” FNAB, which was primarily due to the high cost of this study (it was the main reason for refusal in 76 % of cases). Patients were mainly motivated to know their risk by: a sense of control of the situation and the possibility of taking preventive measures (78 %), future planning for themselves and/or their loved ones (47 %), the possibility of participating in metastatic UM treatment programs (35 %), receiving the maximum amount of information about the disease (28 %). Patients without such intention cited a fear of revealing a high risk of metastases and an impossibility of psychological stabilization based on results of this test.Predicting the risk of metastasis is an important component of an integrated approach to the management of patients with uveal melanoma, including organ-sparing treatment. State funding of this study will increase the satisfaction of psychological needs in this category of cancer patients and improve understanding of the metastasis of uveal melanoma.Молекулярно-генетическое исследование увеальной меланомы (УМ) имеет решающее значение в прогнозировании риска метастазирования этой опухоли. Такой анализ возможен в том числе при проведении органосохраняющего лечения на материале тонкоигольной аспирационной биопсии (ТИАБ), однако не все пациенты могут считать данное исследование целесообразным и/или доступным.Цель: проведение анализа потребности пациентов с УМ в индивидуальном прогнозировании риска развития метастазов.Данное ретроспективное когортное исследование проводилось методом анкетирования 94 пациентов с УМ (средний возраст 60 ± 13 лет; 69 % женщин и 31 % мужчин).Несмотря на достаточно высокое число желающих (77 %), только половина (51 %) пациентов в конечном счете были согласны на проведение «прогностической» ТИАБ, что в первую очередь обусловлено высокой стоимостью данного исследования (в 76 % являлось основной причиной отказа). Среди основных мотивов желания знать риск отмечались следующие: ощущение контроля ситуации и возможность проведения профилактических мер (78 %), планирование дальнейшей жизни для себя и/или близких (47 %), возможность участия в программах лечения метастатической формы УМ (35 %), получение максимального количества информации о заболевании (28 %). Мотивы для отсутствия такого намерения связаны со страхом перед выявлением высокого риска развития метастазов и невозможностью стабилизации психологического состояния по результатам тестирования.Прогнозирование риска метастазирования опухоли является важной составляющей комплексного подхода в ведении пациентов с увеальной меланомой, в том числе при проведении органосохраняющего лечения. Возможность проведения данного исследования на бюджетной основе позволит повысить уровень удовлетворенности психологических потребностей у данной категории онкологических пациентов и улучшить понимание метастатических процессов увеальной меланомы

Комплексный анализ прогностической значимости аберраций хромосомы 8 у пациентов с увеальной меланомой

Introduction. Uveal melanoma ability to metastasize depends on a few prognostic factors. The genetic ones are considered to be the most significant. The role of disorders of the short arm of chromosome 8 (8p), as well as a combination of changes in 8p and the long arm of this chromosome (8q) in the development of metastatic lesions in this pathology remains insufficiently studied.The study objective – to evaluate the prognostic value of chromosome 8 abnormalities in patients with uveal melanoma.Materials and methods. We analyzed 2 retrospective groups of patients who underwent enucleation for uveal melanoma, statistically homogeneous in the main clinical parameters. Group 1 included patients without signs of metastases (n = 41) with an average follow-up period of 71 months, Group 2 included patients with detected metastases (n = 51) and an average follow-up period of 21 months Chromosome abnormalities were tested by multiplex ligation-dependent probe amplification.Results. Three- and five-year survival in patients with uveal melanoma without 8p deletion were 64 and 54 %, respectively; with 8p deletion significantly lower – 25 and 6 %, respectively. The same survival rates in patients with uveal melanoma with 8q amplification were 43 and 26 %, respectively, whereas in patients without 8q amplification they were significantly higher – 80 and 74 %, respectively. In patients with uveal melanoma harbouring both abnormalities, 3- and 5-year survival rates were 26 and 7 %, whereas isolated 8q amplification was associated with 47 and 35 % survival, respectively. These survival rates differ greatly and significantly: hazard ratio 3,26 (95 % confidence interval 1,86–5,69) and 6,89 (95 % confidence interval 2,67–17,73), respectively (р <0,0001).Conclusion. The findings support comprehensive evaluation of chromosome 8 abnormalities as a substantial part of uveal melanoma prognostication. 8q amplification, 8p deletion, combination of these abnormalities and its role in uveal melanoma malignity should be further discovered. Further research in this direction is needed.Введение. Способность увеальной меланомы к метастазированию зависит от целого спектра прогностических факторов, среди которых генетические имеют основополагающее значение. Роль нарушений короткого плеча хромосомы 8 (8р), а также комбинации изменений 8р и длинного плеча этой хромосомы (8q) в развитии метастатического поражения при данной патологии остается недостаточно изученной.Цель исследования – проведение комплексного анализа прогностической значимости аберраций хромосомы 8 у пациентов с увеальной меланомой.Материалы и методы. Были проанализированы 2 ретроспективные группы пациентов, которым была проведена энуклеация по поводу увеальной меланомы, статистически однородные по основным клиническим параметрам. В 1-ю группу вошли больные без признаков метастазов (n = 41) со средним сроком наблюдения 71 мес, во 2-ю группу – больные с выявленными метастазами (n = 51) и средним сроком наблюдения 21 мес. анализ хромосомных нарушений проводился методом мультиплексной амплификации лигированных зондов.Результаты. Трех- и 5-летняя выживаемость пациентов с увеальной меланомой без делеции 8p составила 64 и 54 %, с делецией 8p – 25 и 6 % соответственно. У больных с амплификацией 8q эти показатели были равны 43 и 26 %, у больных без амплификации 8q – 80 и 74 % соответственно. Для пациентов с одновременной амплификацией региона 8q и делецией региона 8р 3- и 5-летняя выживаемость составила 26 и 7 %, тогда как для пациентов с изолированной амплификацией 8q – 47 и 35 % соответственно. Уровень выживаемости пациентов с изолированной амплификацией 8q и комбинацией нарушений (del8p + amp8q) различается существенно и достоверно: отношение рисков 3,26 (95 % доверительный интервал 1,86–5,69) и 6,89 (95 % доверительный интервал 2,67–17,73) (р <0,0001).Заключение. Оценка амплификации 8q, делеции 8p и комбинации этих нарушений должна стать неотъемлемой частью прогнозирования риска метастазирования увеальной меланомы. Необходимы дальнейшие исследования в этом направлении