15 research outputs found

    Anisotropic Magnetoconductance in Quench-Condensed Ultrathin Beryllium Films

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    Near the superconductor-insulator (S-I) transition, quench-condensed ultrathin Be films show a large magnetoconductance which is highly anisotropic in the direction of the applied field. Film conductance can drop as much as seven orders of magnitude in a weak perpendicular field (< 1 T), but is insensitive to a parallel field in the same field range. We believe that this negative magnetoconductance is due to the field de-phasing of the superconducting pair wavefunction. This idea enables us to extract the finite superconducting phase coherence length in nearly superconducting films. Our data indicate that this local phase coherence persists even in highly insulating films in the vicinity of the S-I transition.Comment: 4 pages, 4 figure RevTex, Typos Correcte

    Влияние отмены ИАПФ/БРА на риск развития послеоперационных осложнений в абдоминальной хирургии

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    A significant proportion of patients undergoing non-cardiac surgery receive therapy with angiotensin converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs), which are usually prescribed for treatment of arterial hypertension and CHF. Current guidelines fail to provide clear consensus on whether it is worth discontinuing ACEi/ARBs before non-cardiac surgery. The aim of this research was to assess the contribution of pre-op ACEi/ARBs withdrawal to the development of postoperative complications in patients after abdominal surgery using data from STOPRISK database.Materials and methods. Data of 1945 patients from of the STOPRISK database was used for the analysis. Patients were retrospectively divided into two groups: first group (N=471, 24.2%) included patients subjected to ACEi/ARBs withdrawal 24 hours before surgery, second group (N=1474, 75.8%) included patients continuing on ACEi/ARBs therapy. The 30-day outcomes were analyzed — postoperative complications (acute kidney injury, acute respiratory distress syndrome, anastomosis failure, arrhythmias, circulatory arrest, cardiogenic pulmonary edema, postoperative delirium, myocardial infarction, pneumonia, ileus, postoperative bleeding, pulmonary embolism, acute cerebrovascular accident, wound infection) and mortality. We were not evaluating intraoperative and postoperative arterial hypotension and hypertension, we analyzed the use of vasopressors as a surrogate marker. ACEi/ARBs re-initiation after surgery was not evaluated.Results. One or more post-operative complications were documented in 113 patients (5.8%). Only postoperative delirium was more common in patients (1.06% vs. 0.27%, P=0.027) after ACEi/ARBs withdrawal 24 hours before surgery, the difference reached statistical significance. Sub-analysis in the group of patients with arterial hypertension as the only comorbidity showed no statistically significant differences in the outcomes. Sub-analysis in the group of patients with CFH showed higher incidence of postoperative delirium after ACEi/ARBs withdrawal (2.68% vs. 0.6%, P=0.023). The logistic regression analysis showed that the risk of developing postoperative delirium is influenced by age, vasopressor support, and ACEi/ARBs withdrawal (the area under the curve for the model was 0.92 (0.90–0.93).Conclusion. Rates of pre-op ACEi/ARBs withdrawal (24.2%) are consistent with published data. In the entire cohort, ACEi/ARBs withdrawal resulted in higher incidence of postoperative delirium, as well as in the subgroup of patients with CHF, while ACEi/ARBs withdrawal in the subgroup of patients with arterial hypertension had no influence on postop complications.ACEi/ARBs withdrawal, along with hemodynamic instability and older age, contributes to the development of postoperative delirium, which is the subject of future research. Значительное число пациентов, подвергающихся внесердечным операциям, получает терапию ингибиторами ангиотензинпревращающего фермента (ИАПФ)/блокаторами рецепторов ангиотензина II (БРА), которые обычно назначают в качестве антигипертензивных препаратов и для лечения ХСН. В современных руководствах нет единого мнения о том, стоит ли отменять ИПФ/БРА перед внесердечными операциями.Цель работы — изучение вклада отмены ИАПФ/БРА в развитие послеоперационных осложнений у пациентов в абдоминальной хирургии по данным базы STOPRISK.Методы исследования. В анализ включили данные 1945 пациентов базы данных STOPRISK, которых ретроспективно разделили на пациентов, у которых ИАПФ/БРА отменяли за 24 ч до операции (n=471, 24,2%) и остальных пациентов (n=1474, 75,8%), у которых прием продолжался вплоть до оперативного вмешательства. Изучали 30-дневный исход — послеоперационные осложнения (острое повреждение почек, острый респираторный дистресс-синдром, несостоятельность анастомоза, аритмии, остановка кровообращения, кардиогенный отек легких, послеоперационный делирий, инфаркт миокарда, пневмония, парез кишечника, послеоперационное кровотечение, тромбоэмболия легочной артерии, острое нарушение мозгового кровообращения, раневая инфекция) и летальность. В исследовании не оценивали частоту интраоперационной и послеоперационной гипотензии и гипертензии, применяли суррогатный показатель — частоту применения вазопрессоров. Не оценивали возобновление терапии ИАПФ/БРА в послеоперационный период Результаты. Наличие одного и более осложнения регистрировали у 113 пациентов (5,8%). Статистически значимыми были различия только в частоте послеоперационного делирия — он чаще встречался в группе пациентов, у которых ИАПФ/БРА отменяли за 24 часа до операции (1,06% против 0,27%, р=0,027). При проведении субанализа в подгруппе пациентов, где сопутствующие заболевания были представлены изолированной гипертонической болезнью, статистически значимых различий в исходах не отметили.Субанализ у пациентов, в структуре сопутствующих заболеваний которых присутствовала хроническая сердечная недостаточность, показал большую частоту послеоперационного делирия в группе пациентов, у которых ИАПФ/БРА отменяли (2,68% против 0,6%, р=0,023).Проведенный логистический регрессионный анализ показал, что на риск развития послеоперационного делирия влияют возраст, вазопрессорная поддержка, отмена ИАПФ/БРА (площадь под кривой для модели составила 0,92 (0,90–0,93).Заключение. Частота отмены ИАПФ/БРА (24,2%) соотносится с мировыми данными. В общей когорте отмена ИАПФ/БРА приводила к большей частоте развития послеоперационного делирия, субанализ в группе пациентов с хронической сердечной недостаточностью подтвердил эту закономерность, в группе же пациентов с гипертонической болезнью, отмена ИАПФ/БРА, не влияла на исход. Наряду с гемодинамической нестабильностью и пожилым возрастом, отмена ИАПФ/БРА, вносит вклад в развитие послеоперационного делирия, что требует дальнейшего изучения.

    Large family with both parents affected by distinct BRCA1 mutations: implications for genetic testing

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    Although the probability of both parents being affected by BRCA1 mutations is not negligible, such families have not been systematically described in the literature. Here we present a large breast-ovarian cancer family, where 3 sisters and 1 half-sister inherited maternal BRCA1 5382insC mutation while the remaining 2 sisters carried paternal BRCA1 1629delC allele. No BRCA1 homozygous mutations has been detected, that is consistent with the data on lethality of BRCA1 knockout mice. This report exemplifies that the identification of a single cancer-predisposing mutation within the index patient may not be sufficient in some circumstances. Ideally, all family members affected by breast or ovarian tumor disease have to be subjected to the DNA testing, and failure to detect the mutation in any of them calls for the search of the second cancer-associated allele

    High frequency of BRCA1, but not CHEK2 or NBS1 (NBN), founder mutations in Russian ovarian cancer patients

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    <p>Abstract</p> <p>Background</p> <p>A significant portion of ovarian cancer (OC) cases is caused by germ-line mutations in BRCA1 or BRCA2 genes. BRCA testing is cheap in populations with founder effect and therefore recommended for all patients with OC diagnosis. Recurrent mutations constitute the vast majority of BRCA defects in Russia, however their impact in OC morbidity has not been yet systematically studied. Furthermore, Russian population is characterized by a relatively high frequency of CHEK2 and NBS1 (NBN) heterozygotes, but it remains unclear whether these two genes contribute to the OC risk.</p> <p>Methods</p> <p>The study included 354 OC patients from 2 distinct, geographically remote regions (290 from North-Western Russia (St.-Petersburg) and 64 from the south of the country (Krasnodar)). DNA samples were tested by allele-specific PCR for the presence of 8 founder mutations (BRCA1 5382insC, BRCA1 4153delA, BRCA1 185delAG, BRCA1 300T>G, BRCA2 6174delT, CHEK2 1100delC, CHEK2 IVS2+1G>A, NBS1 657del5). In addition, literature data on the occurrence of BRCA1, BRCA2, CHEK2 and NBS1 mutations in non-selected ovarian cancer patients were reviewed.</p> <p>Results</p> <p>BRCA1 5382insC allele was detected in 28/290 (9.7%) OC cases from the North-West and 11/64 (17.2%) OC patients from the South of Russia. In addition, 4 BRCA1 185delAG, 2 BRCA1 4153delA, 1 BRCA2 6174delT, 2 CHEK2 1100delC and 1 NBS1 657del5 mutation were detected. 1 patient from Krasnodar was heterozygous for both BRCA1 5382insC and NBS1 657del5 variants.</p> <p>Conclusion</p> <p>Founder BRCA1 mutations, especially BRCA1 5382insC variant, are responsible for substantial share of OC morbidity in Russia, therefore DNA testing has to be considered for every OC patient of Russian origin. Taken together with literature data, this study does not support the contribution of CHEK2 in OC risk, while the role of NBS1 heterozygosity may require further clarification.</p

    RESEARCH OF THE ENTRANCE ANGLE EFFECT ON THE REFLECTANCE SPECTRA OF THE STAINLESS STEEL SURFACE OXIDIZED BY PULSED LASER RADIATION

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    Subject of Research.Oxide films on the metal surfaces can be obtained both by surface-uniform infrared heating and local laser treatment e.g. by sequence of nanosecond laser pulses. Due to interference in created films the coloration of treated area is observed. The present work shows the results of spectrophotometric measurements for various light entrance angles in the range of 10-60°. Method. AISI 304 stainless steel plates were oxidized by two methods: in muffle furnace FM - 10 (Т= 500-600° С, t = 5-7 min.) and at line-by-line scanning by sequence of nanosecond laser pulses (λ = 1.06 μm, τ =100 ns, r = 25 μm,q=2.91∙107 W/cm2, Nx = 30, Ny = 1). Surface research in optical resolution was realized by Carl Zeiss Axio Imager A1M. Reflectance spectra were obtained with spectrophotometer Lambda Perkin 1050 with integrating sphere at different fixed light incidence angles. Topographic features were detected by scanning probe microscopy investigation with NanoEducator equipment. Main Results. The quantitative surface geometry characteristics of AISI 304 stainless steel patterns treated by different methods are obtained. It was found that the increase of light entrance angle has no influence on the form of reflection coefficient dependence from a wavelength, but a blue-shift occurs especially for the case of laser treatment. This difference can be caused by surface topology formed by laser heating and variety of oxide film thickness. This effect results in more significant change in observed sample color for laser treatment then for infrared heating. Practical Relevance. The results obtained in the present work can be used to implement a new element of product protection against forgery with the product marking
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