Розкриття сутності поняття виродженості задач лінійного програмування за допомогою системи комп’ютерної алгебри Maple

Розроблено методику викладання симплекс-методу розв’язання виродженої задачі лінійного програмування з використанням системи Maple, що сприяє перенесенню акцентів від формування у студентів навичок рутинних обчислень за формальними правилами до набуття навичок свідомого відтворення ключових етапів симплекс-методу

Outbreak of West Nile virus infection, Volgograd Region, Russia, 1999.

From July 25 to October 1, 1999, 826 patients were admitted to Volgograd Region, Russia, hospitals with acute aseptic meningoencephalitis, meningitis, or fever consistent with arboviral infection. Of 84 cases of meningoencephalitis, 40 were fatal. Fourteen brain specimens were positive in reverse transcriptase-polymerase chain reaction assays, confirming the presence of West Nile/Kunjin virus

Surface topology, electrophysical properties and formation mechanism of tin(ii) sulfide thin films

Photosensitive nanocrystalline SnS films with a size of coherent X-ray scattering regions of about 30 nm were obtained by chemical bath deposition. It has been demonstrated that the deposition time affects significantly both microstructure and thickness of the film as well as the size of the particles’ agglomerates forming the film. The current sensitivity of the obtained films was studied. All synthesized films, regardless of the duration of synthesis, reveal p-type conductivity due to Sn vacancies. Atomic force microscopy measurements and fractal approach provide a detailed description of the processes occurring during film formation. The characteristics of the fabricated SnS films are potentially useful for design of advanced absorbing layers within thin film solar cells. © Kozhevnikova N.S., Maskaeva L.N., Enyashin A.N., Tyutyunnik A.P., Lipina O.A., Selyanin I.O., Markov V.F., 2023.Ministry of Education and Science of the Russian Federation, Minobrnauka; Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, ISSC UB RASPACS 81.10.Dn, 82.60.Lf, 82.70.Dd, 81.05.Hd ABSTRACT Photosensitive nanocrystalline SnS films with a size of coherent X-ray scattering regions of about 30 nm were obtained by chemical bath deposition. It has been demonstrated that the deposition time affects significantly both microstructure and thickness of the film as well as the size of the particles’ agglomerates forming the film. The current sensitivity of the obtained films was studied. All synthesized films, regardless of the duration of synthesis, reveal p-type conductivity due to Sn vacancies. Atomic force microscopy measurements and fractal approach provide a detailed description of the processes occurring during film formation. The characteristics of the fabricated SnS films are potentially useful for design of advanced absorbing layers within thin film solar cells. KEYWORDS tin(II) sulfide, thin films, chemical bath deposition, p-type conductivity, quantum-chemical calculations, formation mechanism ACKNOWLEDGEMENTS This work was carried out in accordance with the scientific and research plans and state assignment of the ISSC UB RAS and Ural Federal University Program of Development within the Priority-2030 Program (Ministry of Science and Higher Education of the Russian Federation). FOR CITATION Kozhevnikova N.S., Maskaeva L.N., Enyashin A.N., Tyutyunnik A.P., Lipina O.A., Selyanin I.O., Markov V.F. Surface topology, electrophysical properties and formation mechanism of tin(ii) sulfide thin films. Nanosystems: Phys. Chem. Math., 2023, 14 (6), 699–704

Landscape science: a Russian geographical tradition

The Russian geographical tradition of landscape science (landshaftovedenie) is analyzed with particular reference to its initiator, Lev Semenovich Berg (1876-1950). The differences between prevailing Russian and Western concepts of landscape in geography are discussed, and their common origins in German geographical thought in the late nineteenth and early twentieth centuries are delineated. It is argued that the principal differences are accounted for by a number of factors, of which Russia's own distinctive tradition in environmental science deriving from the work of V. V. Dokuchaev (1846-1903), the activities of certain key individuals (such as Berg and C. O. Sauer), and the very different social and political circumstances in different parts of the world appear to be the most significant. At the same time it is noted that neither in Russia nor in the West have geographers succeeded in specifying an agreed and unproblematic understanding of landscape, or more broadly in promoting a common geographical conception of human-environment relationships. In light of such uncertainties, the latter part of the article argues for closer international links between the variant landscape traditions in geography as an important contribution to the quest for sustainability

Implementation and outcome of minimally invasive pancreatoduodenectomy in Europe:a registry-based retrospective study A critical appraisal of the first 3 years of the E-MIPS registry

BACKGROUND: International multicenter audit-based studies focusing on the outcome of minimally invasive pancreatoduodenectomy (MIPD) are lacking. The European Registry for Minimally Invasive Pancreatic Surgery (E-MIPS) is the E-AHPBA endorsed registry aimed to monitor and safeguard the introduction of MIPD in Europe. MATERIALS AND METHODS: A planned analysis of outcomes among consecutive patients after MIPD from 45 centers in 14 European countries in the E-MIPS registry (2019-2021). The main outcomes of interest were major morbidity (Clavien-Dindo grade ≥3) and 30-day/in-hospital mortality. RESULTS: Overall, 1336 patients after MIPD were included [835 robot-assisted (R-MIPD) and 501 laparoscopic MIPD (L-MIPD)]. Overall, 20 centers performed R-MIPD, 15 centers L-MIPD, and 10 centers both. Between 2019 and 2021, the rate of centers performing L-MIPD decreased from 46.9 to 25%, whereas for R-MIPD this increased from 46.9 to 65.6%. Overall, the rate of major morbidity was 41.2%, 30-day/in-hospital mortality 4.5%, conversion rate 9.7%, postoperative pancreatic fistula grade B/C 22.7%, and postpancreatectomy hemorrhage grade B/C 10.8%. Median length of hospital stay was 12 days (IQR 8-21). A lower rate of major morbidity, postoperative pancreatic fistula grade B/C, postpancreatectomy hemorrhage grade B/C, delayed gastric emptying grade B/C, percutaneous drainage, and readmission was found after L-MIPD. The number of centers meeting the Miami Guidelines volume cut-off of ≥20 MIPDs annually increased from 9 (28.1%) in 2019 to 12 (37.5%) in 2021 ( P =0.424). Rates of conversion (7.4 vs. 14.8% P &lt;0.001) and reoperation (8.9 vs. 15.1% P &lt;0.001) were lower in centers, which fulfilled the Miami volume cut-off. CONCLUSION: During the first 3 years of the pan-European E-MIPS registry, morbidity and mortality rates after MIPD were acceptable. A shift is ongoing from L-MIPD to R-MIPD. Variations in outcomes between the two minimally invasive approaches and the impact of the volume cut-off should be further evaluated over a longer time period.</p

Implementation and outcome of minimally invasive pancreatoduodenectomy in Europe:a registry-based retrospective study A critical appraisal of the first 3 years of the E-MIPS registry

BACKGROUND: International multicenter audit-based studies focusing on the outcome of minimally invasive pancreatoduodenectomy (MIPD) are lacking. The European Registry for Minimally Invasive Pancreatic Surgery (E-MIPS) is the E-AHPBA endorsed registry aimed to monitor and safeguard the introduction of MIPD in Europe. MATERIALS AND METHODS: A planned analysis of outcomes among consecutive patients after MIPD from 45 centers in 14 European countries in the E-MIPS registry (2019-2021). The main outcomes of interest were major morbidity (Clavien-Dindo grade ≥3) and 30-day/in-hospital mortality. RESULTS: Overall, 1336 patients after MIPD were included [835 robot-assisted (R-MIPD) and 501 laparoscopic MIPD (L-MIPD)]. Overall, 20 centers performed R-MIPD, 15 centers L-MIPD, and 10 centers both. Between 2019 and 2021, the rate of centers performing L-MIPD decreased from 46.9 to 25%, whereas for R-MIPD this increased from 46.9 to 65.6%. Overall, the rate of major morbidity was 41.2%, 30-day/in-hospital mortality 4.5%, conversion rate 9.7%, postoperative pancreatic fistula grade B/C 22.7%, and postpancreatectomy hemorrhage grade B/C 10.8%. Median length of hospital stay was 12 days (IQR 8-21). A lower rate of major morbidity, postoperative pancreatic fistula grade B/C, postpancreatectomy hemorrhage grade B/C, delayed gastric emptying grade B/C, percutaneous drainage, and readmission was found after L-MIPD. The number of centers meeting the Miami Guidelines volume cut-off of ≥20 MIPDs annually increased from 9 (28.1%) in 2019 to 12 (37.5%) in 2021 ( P =0.424). Rates of conversion (7.4 vs. 14.8% P &lt;0.001) and reoperation (8.9 vs. 15.1% P &lt;0.001) were lower in centers, which fulfilled the Miami volume cut-off. CONCLUSION: During the first 3 years of the pan-European E-MIPS registry, morbidity and mortality rates after MIPD were acceptable. A shift is ongoing from L-MIPD to R-MIPD. Variations in outcomes between the two minimally invasive approaches and the impact of the volume cut-off should be further evaluated over a longer time period.</p

Robot-assisted versus laparoscopic pancreatoduodenectomy: a pan-European multicenter propensity-matched study

Background: The use of robot -assisted and laparoscopic pancreatoduodenectomy is increasing, yet large adjusted analyses that can be generalized internationally are lacking. This study aimed to compare outcomes after robot -assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy in a pan-European cohort. Methods: An international multicenter retrospective study including patients after robot -assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy from 50 centers in 12 European countries (2009-2020). Propensity score matching was performed in a 1:1 ratio. The primary outcome was major morbidity (Clavien-Dindo >= III). Results: Among 2,082 patients undergoing minimally invasive pancreatoduodenectomy, 1,006 underwent robot -assisted pancreatoduodenectomy and 1,076 laparoscopic pancreatoduodenectomy. After matching 812 versus 812 patients, the rates of major morbidity (31.9% vs 29.6%; P = .347) and 30-day/inhospital mortality (4.3% vs 4.6%; P = .904) did not differ significantly between robot -assisted pancreatoduodenectomy and laparoscopic pancreatoduodenectomy, respectively. Robot -assisted pancreatoduodenectomy was associated with a lower conversion rate (6.7% vs 18.0%; P < .001) and higher lymph node retrieval (16 vs 14; P = .003). Laparoscopic pancreatoduodenectomy was associated with shorter operation time (446 minutes versus 400 minutes; P < .001), and lower rates of postoperative pancreatic fistula grade B/C (19.0% vs 11.7%; P < .001), delayed gastric emptying grade B/C (21.4% vs 7.4%; P < .001), and a higher R0 -resection rate (73.2% vs 84.4%; P < .001). Conclusion: This European multicenter study found no differences in overall major morbidity and 30day/in-hospital mortality after robot -assisted pancreatoduodenectomy compared with laparoscopic pancreatoduodenectomy. Further, laparoscopic pancreatoduodenectomy was associated with a lower rate of postoperative pancreatic fistula, delayed gastric emptying, wound infection, shorter length of stay, and a higher R0 resection rate than robot -assisted pancreatoduodenectomy. In contrast, robot -assisted pancreatoduodenectomy was associated with a lower conversion rate and a higher number of retrieved lymph nodes as compared with laparoscopic pancreatoduodenectomy. (c) 2024 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Прогнозирование панкреатической фистулы после панкреатодуоденальной резекции с помощью компьютерной томографии

Aim. To reveal and evaluate opportunities of preoperative computer tomography (CT) for pancreatic fistula (PF) prediction after pancreatoduodenectomy.Materials and methods. In 2005 International Study Group on Pancreatic Fistula (ISGPF) developed grading criteria for PF, including asymptomatic biochemical (Grade A), that could be treated conservatively, and clinically relevant (Grade B, Grade C), with consecutive active surgical treatment. For now ISGPF definition of PF is widely accepted. We review the literature since 2005 for original articles in English describing quantitive assessment of the pancreatic parenchyma using CT with histological validation. Low sample trials (&lt;10 cases) were excluded.Results. Three original publications met the inclusion criteria. Fatty and fibrosis infiltration of the pancreatic parenchyma assessed by preoperative CT revealed statistically significant correlation with PF rate.Conclusion. Preoperative CT offers accurate prediction opportunities for postoperative pancreatic fistula and may help caregivers to set up protocols for a strict and early detection of warning clinical signs, to tailor the clinical management of different risk classes, or to select high-risk patients who might be excluded from surgical resection. This would also improve patient selection for relevant research protocols and facilitate a more definitive assessment of collected data related to surgical outcomes, across different institutions and surgeons, and even among different surgeries, in either single-institution or multi-center trials that involve pancreatic surgery.Цель исследования: выявить и оценить возможности прогнозирования панкреатической фистулы после панкреатодуоденальной резекции на основании данных предоперационной компьютерной томографии (КТ).Материал и методы. В 2005 г. Международная рабочая группа по изучению панкреатических фистул (International Study Group on Pancreatic Fistula, ISGPF) разработала критерии градации панкреатических фистул на бессимптомные биохимические (Grade A) и клинически значимые (Grade B и С), требующие терапевтической (Grade A) или хирургической коррекции (Grade B и С). Данная классификация стала общепринятой и широко используется. Проведен анализ литературы, при котором учитывались только оригинальные англоязычные публикации после 2005 г, которые описывали возможности предоперационной количественной оценки плотности поджелудочной железы (ПЖ) с помощью КТ, а данные КТ сопоставлялись с результатами гистологического исследования ткани ПЖ. Работы с малыми выборками (&lt;10 пациентов) были исключены из анализа.Результаты. Критериям включения соответствовали 3 статьи, описывающие возможности КТ для оценки степени фиброза и жировой инфильтрации паренхимы ПЖ, в качестве факторов риска панкреатической фистулы. Выявлена статистически достоверная зависимость данных показателей и риска панкреатической фистулы.Заключение. Современные возможности Кт позволяют объективно судить о риске развития панкреатической фистулы и предоставляют хирургам возможность подобрать наиболее подходящую периоперационную тактику ведения пациента. Прогнозирование риска панкреатической фистулы и формирование гомогенных групп для клинических исследований позволят получать более достоверные результаты при анализе данных даже из разных источников, что, несомненно, повысит качество проводимых исследований

Prevention of hypovitaminosis during pregnancy

The role of vitamins and minerals during pregnancy is undoubtedly relevant. Treatment of hypovitaminosis during pregnancy significantly improves women's health, reduces signs of toxicosis and incidence of congenital malformations of the fetus. Administration of multivitamin complexes safeguards against anemia, decreases the risk of pregnancy failure and prevents abortion

Nutritional support in pregnancy: possibilities for the prevention of obstetric complications

This review focuses on the causes and consequences of nutritional deficiencies in the pregnant woman’s diet, as well as on the possibilities of its supplementation. It has been shown that inadequate intake of vitamins and minerals during pregnancy is accompanied by a lack of nutrient supply to the fetus, which can cause growth retardation, low birth weight and other obstetric and perinatal complications.According to the analysed guidelines and recommendations, the body’s need for vitamins and minerals increases at least twice as much during pregnancy. Adverse effects of the environment, a number of gastrointestinal and liver diseases, chronic diseases, antibiotic therapy, etc. increase this need.However, adequate nutritional support of the fetus is the result of several steps. These include the frequency of maternal food intake, the availability of nutrients in the food and the ability of the placenta to transport substrates effectively to the fetus.The most recommended vitamin for consumption in pregnancy is folic acid, alone or in combination with other B vitamins, as its deficiency leads to birth defects in the child.The authors of this review have reviewed a number of large studies conducted over the past decade that recommend iron and folic acid for pregnant women, regardless of dietary intake, as they have proven beneficial effects on the course and outcome of pregnancy. Folic acid, according to current recommendations, must be prescribed to every pregnant woman in the form of 400 mcg tablets daily regardless of her diet. Other most important and necessary vitamins for pregnant women are: vitamins A, C, D, E, K, B1, B2, B6, B12, PP, pantothenic acid, biotin