Raman spectra observation of silver nanoparticles in porous silicon fabricated by ion implantation

© 2015, Pleiades Publishing, Ltd. Porous silicon layers fabricated by the low-energy high-dose Ag+-ion implantation of crystalline silicon with doses from 7.5 × 1016 to 1.5 × 1017 ion/cm2 are studied by Raman spectroscopy. Pores with sizes from ∼100–180 nm formed on irradiated silicon surface are controlled by scanning electron microcopy. Synthesized silver nanoparticles are observed in the structure of porous silicon. The sizes of pour and nanoparticles are increased with an increase in implantation dose. Acoustic vibrations generated by laser irradiation in silver nanoparticles of various sizes are registered by low-temperature Raman spectra of composite material

Formation of a periodic diffractive structure based on poly(methyl methacrylate) with ion-implanted silver nanoparticles

© 2016, Pleiades Publishing, Ltd.We propose to form optical diffractive elements on the surface of poly(methyl methacrylate) (PMMA) by implanting the polymer with silver ions (E = 30 keV; D = 5.0 × 1014 to 1.5 × 1017 ion/cm2; I = 2 μA/cm2) through a nickel grid (mask). Ion implantation leads to the nucleation and growth of silver nanoparticles in unmasked regions of the polymer. The formation of periodic surface microstructures during local sputtering of the polymer by incident ions was monitored using an optical microscope. The diffraction efficiency of obtained gratings is demonstrated under conditions of their probing with semiconductor laser radiation in the visible spectral range

A diffraction grating created in diamond substrate by boron ion implantation

© 2017, Pleiades Publishing, Ltd.This work is devoted to new method of manufacturing of diffractive optical elements (gratings). A grating was formed in a diamond substrate by implantation with boron ions through a mask. Ion implantation led to the graphitization of diamond in unmasked regions and resulted in swelling of the irradiated layer. The formation of periodic graphitized surface microstructures on the diamond substrate was confirmed by optical, electron, and atomic force microscopy. The efficiency of operation of the obtained diffractive optical element was demonstrated by probing with He–Ne laser radiation

The formation of periodic diffractive plasmonic nanostructures with implanted copper nanoparticles by local ion etching of silica glass

Silica glass was subjected to a low-energy implantation with 40-keV Cu+ ions at a dose of 7.5 × 1016 ions/cm2 and an ion-beam current density of 5 μA/cm2 through a surface metal-wire mask with square holes of ∼40 μm. The formation of copper nanoparticles in the glass was determined from the occurrence of characteristic plasmon optical absorption and through the detection of particles using an atomic force micro- scope. The formation of periodic surface microstructures via the local etching of silica glass during implantation was observed using a scanning electron microscope. The operating efficiency of the diffractive optical plasmonic element based on silica glass microstructures with metallic copper nanoparticles was shown during its sounding by the emission of a helium-neon laser. © 2013 Pleiades Publishing, Ltd

Synthesis of periodic plasmonic microstructures with copper nanoparticles in silica glass by low-energy ion implantation

Ion implantation was used to locally modify the surface of silica glass to create periodic plasmonic microstructures with Cu nanoparticles. Nanoparticles were synthesized by Cu-ion irradiation of the silica glass at the ion energy of 40 keV, dose of 5×1016 ions/cm2 and current density of 5 μA/cm2. This procedure involves low-energy ion implantation into the glass through a mask placed at the surface. Formation of nanoparticles was observed by optical spectroscopy and atomic force microscopy. The presented results clearly demonstrate how the low-energy ions can be used for the fabrication of photonic microstructures on dielectric surfaces in a single-step process. © 2012 Springer-Verlag Berlin Heidelberg

Prediction of clinical course in patients with diffuse coronary artery disease after coronary bypass surgery

Aim. To determine the incidence, predictors and develop a model for long-term risk stratification of ischemic events in patients with coronary artery disease after coronary bypass surgery.Material and methods. This retrospective study of the clinical course in patients with diffuse coronary artery disease (CAD) after coronary endarterectomy and bypass grafting surgery. A total of 232 patients were included, while long-term outcomes were assessed in 202 patients. Among them, complete data on clinical status were obtained from survivors (n=191). The median follow-up was 60 (interquartile range, 42; 74) months, while the minimum follow-up — 12 months, the maximum was 96 months. The primary composite endpoint reflecting the unfavorable course of CAD included coronary ischemic events (recurrent angina, myocardial infarction, repeat revascularization), while secondary endpoint — allcause mortality. The factors influencing the development of primary and secondary endpoints were studied.Results. An unfavorable CAD course was diagnosed in 39 patients (20,4%), while 11 deaths were recorded (5,4%). Univariate analysis demonstrated a significant role of prior myocardial infarction in the increase in mortality rate (p=0,029). Among the factors influencing the CAD course, no significant differences were obtained for any of them. A multivariate analysis was performed to identify a high-risk group for an unfavorable course of diffuse CAD. Independent predictors were identified, the most significant contribution of which was made by multifocal atherosclerosis (odds ratio (OR)=1,99, 95% confidence interval (CI), 0,93-4,21, p=0,072), low adherence to secondary prevention measures (OR=2,21, 95% CI, 0,86-6,89, p=0,128) and diabetes (OR=1,73, 95% CI, 0,79-3,72, p=0,162). Using the results obtained, a prognostic model with high specificity (64%) and moderate sensitivity (53%) was created.Conclusion. The highest probability of an unfavorable long-term course of diffuse CAD was noted in patients with diabetes, multifocal atherosclerosis, and low adherence to secondary prevention measures. The obtained results make it possible to identify a high-risk group in this cohort of patients, determine the reserve of secondary prevention measures and a direction of actions to improve outcomes

Отдаленные исходы коронарного шунтирования у больных с распространенным атеросклеротическим поражением коронарного и периферического сосудистых бассейнов (по данным регистра длительной антитромботической терапии РЕГАТА)

Introduction. Multifocal atherosclerosis (MFA) in patients with CHD is a key risk factor for thrombotic complications (TC). There are little data on the long-term prognosis in patients with multivessel CHD combined with carotid artery lesions.Objective. To assess prognostic negative outcomes (thrombosis and bleeding) in patients with CHD and MFA undergoing revascularization procedures – coronary artery bypass graft surgery and, in case of high risk of ischemic stroke, carotid endarterectomy.Materials and methods. A total of 189 patients with stable multivessel coronary artery disease who successfully underwent coronary bypass graft surgery and had concomitant atherosclerosis of the carotid arteries ≥50% were included in the study. The exclusion criterion was chronic use of oral anticoagulants. The choice of antithrombotic therapy after the surgical intervention was determined by the attending physicians. The efficacy endpoint was defined as the sum of TC including cardiovascular death, acute coronary syndrome, ischemic stroke, acute lower limb ischemia, and the need for emergency revascularization of the carotid or coronary basins. BARC bleeding types 2-5 were considered as a safety endpoint.Results. The median follow-up period was 37 months. [MR 25.0; 45.0]. The cumulative incidence of TC was 11.1%, BARC 2-5 bleeding was 4.8%. One or two antiplatelet agents were prescribed at discharge in 87.3% of cases, and in 12.7% – a combination of acetylsalicylic acid (ASA) and oral anticoagulant (OAC) for up to 6 months. The incidence of thrombotic complications was not significantly different in the mono- or dual antiplatelet therapy groups. The combination therapy group (OAC + ASA) was characterized by the highest number of comorbidities. When analyzing the TC for the first 6 months. (before anticoagulant withdrawal) there was no significant difference between the groups of antiplatelet therapy and the combination of ASA and OAC (Log-Rank, p = 0.4669). The proportion of patients who survived the entire follow-up period without developing TC was significantly higher in the group compared to the initial combination therapy group: 0.83 versus 0.50 (Log-Rank, p = 0.0101).Conclusion. Despite complete revascularization, the incidence of TC during the two years of follow-up was high. In the combination therapy group, anticoagulant withdrawal led to an increased incidence of TC.Введение. Мультифокальный атеросклероз (МФА) у больных ИБС – ключевой фактор риска тромботических осложнений (ТО). Сведения об отдаленном прогнозе у больных многососудистой ИБС, сочетающейся с поражением сонных артерий, немногочисленны.Цель. Оценить определяющие прогноз негативные исходы (тромбозы и кровотечения) у больных с ИБС и МФА, подвергнутых процедурам реваскуляризации – коронарному шунтированию и, в случае высокого риска ишемического инсульта, каротидной эндартерэктомии.Материалы и методы. Всего в исследование включено 189 пациентов со стабильной многососудистой ИБС, успешно перенесших операцию коронарного шунтирования и имеющих сопутствующий атеросклероз сонных артерий ≥ 50%. Критерий исключения – хронический прием пероральных антикоагулянтов. Выбор антитромботической терапии после оперативного вмешательства определяли лечащие врачи. Конечную точку эффективности определяли как сумму ТО, включавшую сердечно-сосудистую смерть, острый коронарный синдром, ишемический инсульт, острую ишемию нижних конечностей, потребность в неотложной реваскуляризации каротидного или коронарного бассейнов. Конечной точкой безопасности считали кровотечения BARC типов 2–5.Результаты. Медиана периода наблюдения составила 37 мес. [ИКР 25,0; 45,0]. Суммарная частота ТО составила 11,1%, BARC 2–5 кровотечений — 4,8%. В 87,3% случаев при выписке назначали один или два антиагреганта, в 12,7% – комбинацию ацетилсалициловой кислоты (АСК) и орального антикоагулянта (ОАК) на срок до 6 мес. Частота тромботических осложнений в группах моно- или двойной антиагрегантной терапии значимо не отличалась. Группа комбинированной терапии (ОАК + АСК) характеризовалась наибольшим количеством сопутствующих заболеваний. При анализе ТО за первые 6 мес. (до отмены антикоагулянта) достоверной разницы между группами антиагрегантной терапии и комбинации АСК с ОАК не выявлено (Log-Rank, p = 0,4669). Доля пациентов, проживших весь период наблюдения без развития ТО, оказалась достоверно больше в группе антиагрегантной терапии в сравнении с группой начальной комбинированной терапии: 0,83 против 0,50 (Log-Rank, p = 0,0101).Заключение. Несмотря на полную реваскуляризацию, частота ТО на протяжении двух лет наблюдения оказалась высокой. В группе комбинированной терапии отмена антикоагулянта приводила к увеличению частоты ТО

Sanctions as a means of social control in the system of international relations

The work deals with sanctions as a means of social control used by national, sovereign states in the system of international relations, the causes and possibilities of their application, consequences.В работе рассматриваются санкции как средство социального контроля, используемые национальными, суверенными государствами в системе международных отношений, причины и возможности их применения, последствия

Raman spectra observation of silver nanoparticles in porous silicon fabricated by ion implantation

© 2015, Pleiades Publishing, Ltd. Porous silicon layers fabricated by the low-energy high-dose Ag+-ion implantation of crystalline silicon with doses from 7.5 × 1016 to 1.5 × 1017 ion/cm2 are studied by Raman spectroscopy. Pores with sizes from ∼100–180 nm formed on irradiated silicon surface are controlled by scanning electron microcopy. Synthesized silver nanoparticles are observed in the structure of porous silicon. The sizes of pour and nanoparticles are increased with an increase in implantation dose. Acoustic vibrations generated by laser irradiation in silver nanoparticles of various sizes are registered by low-temperature Raman spectra of composite material