178 research outputs found

    Application of secondary ion mass spectrometer for measuring the diffusion profiles in alkali-halide crystals

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    Depth profiles of magnesium, fluorine and oxygen impurities was examined in the surface layers of alkali-halide KBr crystals using method of secondary ion mass spectrometry. Samples of potassium bromide, coated with a surface film of magnesium fluoride were subjected to isothermal diffusion annealing in air at various times. It is shown that the diffusion of O ions occurs from the ambient atmosphere besides the diffusion of Mg and F ions during annealing of KBr crystals. Accurate estimation of the diffusion coefficients of cationic impurity Mg requires taking into account the possible interaction of this impurity and oxygen

    Diabetes mellitus and long-time outcomes of autovenous femoro-popliteal bypass

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    BACKGROUND: the effect of diabetes mellitus on the long-term patency of autovenous femoro-popliteal bypass has not been definitively determined AIM: to determine the effect of diabetes mellitus on the long-term outcomes of autovenous femoral-popliteal bypass.MATERIALS AND METHODS: the results of treatment of 648 patients who underwent autovenous femoral-popliteal bypass were analyzed. The patients were divided into 2 clinical groups: the first group included 367 patients with diabetes mellitus, the second — 281 patients without the named disease. The groups did not differ significantly in the incidence of concomitant pathology.RESULTS: occlusion of the autovenous conduit within a 5-year period after surgical treatment was observed in 218 patients of the first group (59.4%) and 72 patients of the second group (25.6%) (p <0.01, χ2 = 39.05, RR = 1.78; CI = 1.53–2.12). The average service life of the autovenous femoral-popliteal bypass was 63.49 months in patients of the first group, and 107.46 months in the second. The decompensated course of diabetes mellitus was observed in 203 patients (55.2%). Among patients with decompensated diabetes mellitus, occlusion of the autovenous femoral-popliteal bypass was observed in 95 patients (46.8%), in 104 patients the autovenous conduit was passable (51.2%; p = 0.449, χ2 = 0.57). Decompensated course of diabetes mellitus may contribute to a decrease in the service life of autovenous femoro-popliteal bypass.CONCLUSION: the presence of diabetes mellitus, and especially its decompensated course, can negatively affect the patency of autovenous femoro-popliteal bypass in the long term

    Thermodynamic models of radiation-induced processes in solids

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    A thermodynamic model is proposed to qualitatively describe the radiation-induced processes in solids: temperature dependence of the X-ray radio luminescence output, dependence of these processes on the excitation density, energy accumulating in a solid under exposure to ionizing radiation and its temperature dependence. The proposed model and the formula derived can be used to develop radiation-resistant and radiation-sensitive materials

    Solar ultraviolet radiation exposure, and incidence of childhood acute lymphocytic leukaemia and non-Hodgkin lymphoma in a US population-based dataset

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    Background: Acute lymphocytic leukaemia (ALL) and non-Hodgkin lymphoma (NHL) are among the commonest types of childhood cancer. Some previous studies suggested that elevated ultraviolet radiation (UVR) exposures increase ALL risk; many more indicate NHL risk is reduced. Methods: We assessed age&lt;20 ALL/NHL incidence in Surveillance, Epidemiology and End Results data using AVGLO-derived UVR irradiance/cumulative radiant exposure measures, using quasi-likelihood models accounting for underdispersion, adjusted for age, sex, racial/ethnic group and other county-level socioeconomic variables. Results: There were 30,349 cases of ALL and 8062 of NHL, with significant increasing trends of ALL with UVR irradiance (relative risk (RR) = 1.200/mW/cm2 (95% CI 1.060, 1.359, p = 0.0040)), but significant decreasing trends for NHL (RR = 0.646/mW/cm2 (95% CI 0.512, 0.816, p = 0.0002)). There was a borderline-significant increasing trend of ALL with UVR cumulative radiant exposure (RR = 1.444/MJ/cm2 (95% CI 0.949, 2.197, p = 0.0865)), and significant decreasing trends for NHL (RR = 0.284/MJ/cm2 (95% CI 0.166, 0.485, p &lt; 0.0001)). ALL and NHL trend RR is substantially increased among those aged 0–3. All-age trend RRs are most extreme (increasing for ALL, decreasing for NHL) for Hispanics for both UVR measures. Conclusions:Our more novel finding, of excess UVR-related ALL risk, is consistent with some previous studies, but is not clear-cut, and in need of replication.</p

    Prospects for the measurement of muon-neutrino disappearance at the FNAL-Booster

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    Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle θ13\theta_{13} in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small L/EL/E, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. This proposal refers to the use of magnetic spectrometers at two different sites, Near and Far. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the CERN project for a new more performant neutrino beam, which will nicely extend the physics results achievable at the Booster. The possible FNAL experiment will allow to clarify the current νμ\nu_{\mu} disappearance tension with νe\nu_e appearance and disappearance at the eV mass scale. Instead, a new CERN neutrino beam would allow a further span in the parameter space together with a refined control of systematics and, more relevant, the measurement of the antineutrino sector, by upgrading the spectrometer with detectors currently under R&D study.Comment: 76 pages, 52 figure

    Recovery surgery for extracapsular extension of squamous cell cancer metastasizing to the lymph nodes in the neck

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    Metastatic neck lymph nodes in massive lesion of their tissue with tumor cells are accompanied by extracapsular extension to the adjacent structures in a number of cases. The greatest problem in clinical oncology is when even extended radical neck dissection fails to completely remove tumor tissue that is macroscopically detectable after surgical resection. In this situation, there is a continued growth of tissue mass that is left on the neck. Thus, the unresectable extracapsular spread of neck lymph node metastases to the adjacent tissues reduces the duration of life in the patients and worsens its quality.The basis for this investigation is clinical observations of patients who have been operated on at the Nizhny Novgorod Regional Clinical Oncology Dispensary (Hospital Two) in the period 2005 to 2016. Histologically, the tumors were squamous cell carcinomas. In this period, there have been 24 Crile operations (radical neck dissection) that are cytoreductive. A primary tumor has been (n = 15) or has not been (n = 9) previously excised. The extracapsular spread of metastatic lymph nodes corresponded to levels IIa, IIb, and III. Cytoreductive cervical lymphadenectomy with the pectoralis musculocutaneous flap covering an unresectable tumor for extracapsular unresectable squamous cell carcinoma metastasizing to the neck lymph nodes should be considered the operation of recovery. This type of surgery is warranted, as tumor mass reduction by eliminating the source of intoxication allows further antitumor treatment (radiotherapy or chemotherapy or their combination) that is contraindicated in patients with tumor lysis in the neck. When the cause of death is the exceedingly continued growth of an unresectable component of radio- and chemoresistant variants of tumor tissue on the neck, the covering of the component with a pectoralis major flap delays a fatal outcome in incurable patients to improve a number of quality-of-life indicators

    Функциональное состояние кардиореспираторной системы после ортотопической трансплантации сердца с длительной холодовой ишемией трансплантата

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    Objective: to assess the functional state of the cardiorespiratory system in the long term after orthotopic heart transplantation (HT) with prolonged cold ischemia time. Materials and methods. The results of 60 orthotopic HTs performed at Meshalkin National Medical Research Center were analyzed. A comparison was made of the immediate and long-term outcomes of HTs in the group with cold ischemia time lasting for less than 240 minutes and in those with farther distance between donor and recipient sites with cold ischemia time of 240 minutes or more. In the long-term follow-up after HT, all patients underwent cardiopulmonary exercise testing, body plethysmography, assessment of the diffusing capacity of the lungs, and quality of life assessment. Results. Prolonged cold ischemia showed a negative effect on the early postoperative period – decreased myocardial contractility on postoperative day 1 and longer duration of inotropic support. At the same time, the survival rate and incidence of graft rejection reactions in the early and late post-HT periods in the studied groups did not differ significantly. Peak oxygen consumption in the general group in the long term after HT was 17 (14.7–21.0) mL/kg/min, VE/ VCO2 slope was 30 (29–36) at 100 (90–120) W threshold load power. All the parameters of pulmonary function tests did not differ significantly depending on cold ischemia duration. Quality of life also did not show significant differences depending on the duration of graft ischemia in terms of both physical and psycho-emotional health components of the SF-36 questionnaire. Conclusion. Long-term cold ischemia of the graft did not show any negative impact on the functional state of the cardiorespiratory system and quality of life in the long term after HT. The studied group of recipients was characterized by high efficiency of pulmonary ventilation and gas exchange, as well as high tolerance to physical activity in the long-term post-HT period.Цель. Оценка функционального состояния кардиореспираторной системы в отдаленные сроки после ортотопической трансплантации сердца (ТС) с длительной холодовой ишемией трансплантата. Материалы и методы. Проанализированы результаты 60 ортотопических ТС, выполненных в ФГБУ «НМИЦ им. акад. Е.Н. Мешалкина» Минздрава России. Проведено сравнение непосредственных и отдаленных результатов ТС в группах с холодовой ишемией трансплантата менее 240 минут и при дистанционном изъятии с холодовой ишемией 240 минут и более. В отдаленные сроки после ТС всем пациентам проведено кардиопульмональное нагрузочное тестирование, бодиплетизмография, оценка диффузионной способности легких, оценка качества жизни. Результаты. Длительная холодовая ишемия донорского сердца показала негативное влияние на ранний послеоперационный период ТС в виде снижения сократительной способности миокарда в первые сутки после операции и увеличения длительности инотропной поддержки. При этом выживаемость и частота развития реакций отторжения трансплантата в ранние и отдаленные сроки после ТС в изучаемых группах значимо не различалась. Пиковое потребление кислорода в отдаленные сроки после ТС в общей группе составило 17 (14,7–21,0) мл/мин/кг, VE/VCO2 slope – 30 (29–36) при пороговой мощности нагрузки 100 (90–120) Вт. Все параметры легочных функциональных тестов не имели значимых отличий в зависимости от длительности холодовой ишемии. Качество жизни также не показало значимых различий в зависимости от длительности ишемии трансплантата как по физическому, так и психоэмоциональному компонентам здоровья опросника SF-36. Заключение. Длительная холодовая ишемия трансплантата не показала отрицательного влияния на функциональное состояние кардиореспираторной системы и качество жизни в отдаленные сроки после ТС. Изучаемая группа реципиентов характеризовалась высокой эффективностью легочной вентиляции и газообмена, а также высокой толерантностью к физическим нагрузкам в отдаленные сроки после ТС

    Myocardial revascularization in patients with acute coronary syndrome in the context of COVID-19 pandemic: a single-center prospective cohort study

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    Aim. To assess the outcomes of myocardial revascularization (MR) and identify risk factors for early postoperative complications in patients with coronary artery disease (CAD) with acute coronary syndrome (ACS) in the context of coronavirus disease 2019 (COVID-19) pandemic.Material and methods. The study included 769 patients aged 67,0±4,4 years with CAD with ACS in the period from April to October 2020. In an expedited manner, percutaneous transluminal coronary angioplasty (n=699) and on pump coronary artery bypass grafting (CABG) (n=70) were performed. All patients underwent a COVID-19 rapid tests. After MR, the following outcomes were recorded: adverse cardiovascular events and other complications; various surgical interventions; bilateral COVID-19 pneumonia; death. The follow-up period lasted 30 days.Results. During the hospitalization, COVID-19 was detected in 5,3% of patients (n=41). Among them, bilateral multisegmental pneumonia developed in 48,8%. Among infected patients, COVID-19-related mortality in the early postoperative period was 9,8%. The all-cause mortality rate was 0,7%. On pump CABG significantly increases the risk of developing COVID-19 pneumonia (odds ratio (OR), 23,2; 95% confidence interval (CI) 14,2-35,4; p&lt;0,001). After MR, COVID-19 pneumonia was associated with respiratory (OR, 7,6; 95% CI, 4,3-11,5; p=0,001) and heart failure (OR, 4,2; 95% CI, 2,9-8,6; p=0,001), atrial fibrillation (OR, 8,3; 95% CI, 4,1-13,9; p=0,001), as well as with all-cause mortality (OR, 10,3; 95% CI, 5,2-16,7; p=0,005). Recurrent transmural myocardial infarction in patients with CAD was associated with heart failure after MR (OR, 7,1; 95% CI, 2,4-12,6; p=0,012).Conclusion. Conducting on pump CABG in patients with CAD with ACS is the leading trigger for developing COVID-19 pneumonia, which, during hospitalization after MR, was associated not only with respiratory complications, but also with impaired heart function, which significantly increases the death risk in this category of patients

    Modelling the bimodal distribution of indoor gamma-ray dose-rates in Great Britain

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    Gamma radiation from naturally occurring sources (including directly ionizing cosmic-rays) is a major component of background radiation. An understanding of the magnitude and variation of doses from these sources is important, and the ability to predict them is required for epidemiological studies. In the present paper, indoor measurements of naturally occurring gamma-rays at representative locations in Great Britain are summarized. It is shown that, although the individual measurement data appear unimodal, the distribution of gamma-ray dose-rates when averaged over relatively small areas, which probably better represents the underlying distribution with inter-house variation reduced, appears bimodal. The dose-rate distributions predicted by three empirical and geostatistical models are also bimodal and compatible with the distributions of the areally averaged dose-rates. The distribution of indoor gamma-ray dose-rates in the UK is compared with those in other countries, which also tend to appear bimodal (or possibly multimodal). The variation of indoor gamma-ray dose-rates with geology, socio-economic status of the area, building type, and period of construction are explored. The factors affecting indoor dose-rates from background gamma radiation are complex and frequently intertwined, but geology, period of construction, and socio-economic status are influential; the first is potentially most influential, perhaps, because it can be used as a general proxy for local building materials. Various statistical models are tested for predicting indoor gamma-ray dose-rates at unmeasured locations. Significant improvements over previous modelling are reported. The dose-rate estimates generated by these models reflect the imputed underlying distribution of dose-rates and provide acceptable predictions at geographical locations without measurements
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