Geological and Geomechanical Model of the Verkhnekamsk Potash Deposit Site

Major accidents at OJSC Uralkali raised the question of the need for a detailed study of the geological structure of the Verkhnekamskoye potassium salt deposit, the identification of anomalous complex zones in the oversalt rocks and, above all, in the water-blocking layer (WBL). The article proposes a method for isolating weakened zones in the WBL and potash reservoirs, based on the combined use of geomechanical (laboratory core tests) and geophysical (acoustic broadband logging in wells and surface seismic exploration) studies. It also describes the method of zoning of WBLand potash reservoirs on the physical and mechanical properties to obtain their specific values. This technique will help solve the most urgent problem of ensuring industrial safety in the development of the Verkhnekamskoye potassium salt deposit (the safety of the WBL). The implementation of the proposed method is considered for the Romanovsky site of the Verkhnekamskoye deposits of potassium and magnesium salts. The research included 2D seismic explorations, physical and mechanical properties testing, and finding statistical dependencies between static and dynamic geomechanical parameters. Based on the processing of seismic materials and the obtained dependencies, a geological and geomechanical model of this area was created, and zones with different physicomechanical properties were identified

On the nature of picobirnaviruses

The picobirnaviruses (Picobirnaviridae, Picobirnavirus, PBVs) are currently thought to be animal viruses, as they are usually found in animal stool samples. However, no animal model or cell culture for their propagation has yet been found. In 2018, a hypothetical assumption about PBVs belonging to prokaryotic viruses was put forward and experimentally substantiated. This hypothesis is based on the presence of Shine–Dalgarno sequences in the genome of all PBVs before three reading frames (ORF) at the ribosomal binding site, with which the prokaryotic genome is saturated, while in the eukaryotic genome such regions occur with low frequency. The genome saturation with the Shine–Dalgarno sequences, as well as the preservation of this saturation in the progeny, according to scientists, allows us to attribute PBVs to prokaryotic viruses. On the other hand, there is a possibility that PBVs belong to viruses of eukaryotic hosts – fungi or invertebrates, since PBV­like sequences similar to the genome of fungal viruses from the families of mitoviruses and partitiviruses have been identified. In this regard, the idea arose that, in terms of reproduction mode, PBVs resemble fungal viruses. The divergence of views on the true PBV host(s) has sparked discussions among scientists and required further research to elucidate their nature. The review highlights the results of the search for a PBV host. The reasons for the occurrence of atypical sequences among the PBV genome sequences that use an alter­ native mitochondrial code of lower eukaryotes (fungi and invertebrates) for the translation of viral RNA­dependent RNA polymerase (RdRp) instead of the standard genetic code are analyzed. The purpose of the review was to collect arguments in support of the hypothesis about the phage nature of PBVs and to find the most realistic explanation of the reasons for identifying non­standard genomic sequences for PBVs. Based on the hypothesis about the genealogical relationship of PBVs with RNA viruses from other families with similar segmented genomes, such as Reoviridae, Cystoviridae, Totiviridae and Partitiviridae, virologists support the assumption of a decisive role in the origin of atypical PBV­like reassortment strains between PBVs and viruses of the listed families. The collected arguments given in this review indicate a high probability of a phage nature of PBVs. The data presented in the review show that the belonging of PBV­like progeny to prokaryotic or eukaryotic viruses is determined not only by its genome saturation level with a prokaryotic motif, standard or mitochondrial genetic code. The primary structure of the gene encoding the viral capsid protein responsible for the presence or absence of specific proteolytic properties of the virus that determine its ability for independent horizontal transmission into new cells may also be a decisive factor

Picobirnaviruses: prevalence, genetic diversity, detection methods

This article presents a general overview of the prevalence, genetic diversity and detection methods of picobirnaviruses (PBVs), which are small, non-enveloped icosahedral viruses with a segmented double-stranded RNA genome consisting of two segments taxonomically related to the genus Picobirnavirus of the family Picobirnaviridae. This review of scientific papers published in 1988–2019 provides data on the PBV distribution in the nature and a broad host range. PBV infection is characterized as opportunistic, the lack of understanding of the etiological role of PBVs in diarrhea is emphasized, since these viruses are detected both in symptomatic and asymptomatic cases. The concept of PBV infection as a chronic disease caused by a long-lasting persistence of the virus in the host is considered. Such factors as stress syndrome, physiological conditions, immune status and host age at the time of primary PBV infection influence the virus detection rate in humans and animals. The possible zoonotic nature of human PBV infection is noted due to the capacity for interspecies PBV transmission acquired during evolution as a result of the reassortment of the genome segments of different viruses infecting the same host. Data providing evidence that PBVs belong to eukaryotes and a challenging hypothesis stating that PBVs are bacterial viruses are presented. The need to intensify work on PBV detection because of their wide distribution, despite the complexity due to the lack of the cultivation system, is emphasized. Two strategies of RT-PCR as main PBV detection methods are considered. The genomes of individual representatives of the genus isolated from different hosts are characterized. Emphasis is placed on the feasibility of developing primers with broader specificity for expanding the range of identifiable representatives of the genus PBV due to a huge variety of their genotypes. The importance of effective monitoring of PBV prevalence for studying the zoonotic and anthroponotic potential using metagenomics analysis is highlighted, and so is the possibility of using PBV as a marker for environmental monitoring

The relationship of fracture toughness coefficients and geophysical characteristics of rocks of hydrocarbon deposits

This paper contains the results of laboratory tests to determine the fracture toughness coefficient KIC of rocks for terrigenous and carbonate objects by three methods. The tests were carried out by different methods due to the lack of a standard method for determining the fracture toughness characteristics of rocks in Russia. We used the following methods for determining the KIC coefficient: the extension of core specimens with an annular fracture, the action of a concentrated load on a beam specimen with a fracture and the method of bending semi-circular samples with a fracture according to ISRM recommendations. The paper presents the relationship of the fracture toughness coefficients with the P-wave velocity and porosity. The obtained dependencies characterize the general trend of changing for the studied parameter and can be used in the design of hydraulic fracturing in the fields for which tests were conducted

Новые возможности дренажной хирургии рефрактерной глаукомы

Glaucoma is a socially significant disease, which is consistently ranked first or second among causes of visual impairment and blindness. Difficulties with diagnosis verification, treatment algorithms, monitoring, patient compliance to treatment regimens that occur at a certain stage of therapy, as well as medication prescriptions inefficiency lead to progressive vision loss. Numerous surgical techniques often have limited effectiveness. Drainage use is aimed at reducing excessive scarring in filtration area and creating one or more paths of intraocular fluid resorption. The review presents currently existing approaches to refractory glaucoma drainage surgery. Different implant groups are described in details, including those reducing excessive scarring, intracameral drainages and Schlemm's canal implants. Current perceptions of viscocanalostomy and canaloplasty effectiveness in glaucoma surgery are recounted. The advantages of implants, designed to maintain the Schlemm's canal volume, are specified. NiTi is a promising new material for use in glaucoma drainage surgery. Technical characteristics of biocompatibility, possibilities of modern engineering and technical lasers for processing NiTi allow to use this material on microstructural level.Глаукома относится к социально значимым заболеваниям, стабильно находясь на первом или втором местах среди причин ухудшения зрения и слепоты. Трудности с верификацией диагноза, алгоритмами лечения, наблюдения, приверженностью пациента схемам лечения, возникающая на определенном этапе терапии неэффективность медикаментозных назначений приводят к прогрессирующей потере зрения. Многочисленные методики хирургического воздействия зачастую имеют ограниченную эффективность. Использование эксплантодренажей направлено как на снижение избыточного рубцевания в фильтрационной зоне, так и создание одного или нескольких путей резорбции внутриглазной жидкости. В обзоре представлены существующие на сегодняшний день подходы к дренажной хирургии рефрактерной глаукомы. Отдельно рассмотрены группы имплантатов, снижающих избыточное рубцевание, интракамеральные дренажи и имплантаты шлеммова канала. Описаны существующие представления об эффективности вискоканалостомии и каналопластики при хирургии глаукомы. Приведены преимущества имплантатов, направленных на поддержание объема шлеммова канала. Никелид титана - новый перспективный материал для использования в дренажной хирургии глаукомы. Технические характеристики, биологическая совместимость, возможности современного машиностроения и технических лазеров для обработки никелида титана позволяют использовать этот сплав на микроструктурном уровне

Влияние несостоятельности анастомоза на онкологические результаты лечения больных раком прямой кишки

Background. The effect of anastomotic leakage (AL) on oncological outcomes after total mesorectumectomy is controversial.Objective: to investigate the influence of AL and other factors on oncological outcome.Materials and methods. Data of 67 patients underwent total mesorectumectomy with normal healing were compared with those for 16 patients who experienced AL. Long-term oncological outcomes were analysed.Results. Median follow-up was 43 months. AL rate was 19.4 % (16 cases out of 83). Following factors had negative influence on lower 4-year disease-free survival rate and reached statistical significance in univariant analysis: tumor invasion (hazard ratio (HR) 8.8; 95 % сonfidence interval (CI) 1.4–13.7; р = 0.01), metastases in regional lymph nodes (HR 3.5; 95 % CI 1.2–12.3; р = 0.03), tumor stage (р = 0.048), level of tumor differentiation (HR 0.1; 95 % CI 0–0.6; р <0.0001), tumor stenosis (HR 8.8; 95 % CI 1.4–13.7; р = 0.002), AL (HR 3.9; 95 % CI 1.6–37.1; р = 0.01). In the logistic regression analysis independent risk factors for the development of recurrence were not revealed.Conclusion. AL was not proved to be a risk factor of worse oncological outcome. Hence, additional adjuvant treatment or extended follow-up on the basis of the occurrence of AL after low anterior resection of rectal cancer might not be justified.Цель исследования – оценить влияние НА и других факторов риска на онкологический результат лечения.Материалы и методы. Данные 67 пациентов, перенесших тотальную мезоректумэктомию, с целостным анастомозом сравнивали с данными 16 пациентов с диагностированной НА. Проанализированы долгосрочные онкологические результаты.Результаты. Медиана наблюдения составила 43 мес. Частота НА составила 19,3 % (16 случаев из 83). В однофакторном анализе статистически значимыми факторами, снижающими уровень 4-летней выживаемости, стали степень инвазии опухоли (отношение рисков (OР) 8,8; 95 % доверительный интервал (ДИ) 1,4–13,7; р = 0,01), наличие метастазов в регионарных лимфатических узлах (OР 3,5; 95 % ДИ 1,2–12,3; р = 0,03), стадия болезни (р = 0,048), уровень дифференцировки опухоли (ОР 0,1; 95 % ДИ 0–0,6; р <0,0001), стенозирующий характер опухоли (OР 8,8; 95 % ДИ 1,4–13,7; р = 0,002), НА (OР 3,9; 95 % ДИ 1,6–37,1; р = 0,01). В логистическом регрессионном анализе независимых факторов риска развития рецидива не выявлено.Заключение. НА не является фактором риска плохого онкологического исхода. Таким образом, дополнительное лечение адъювантом или сокращение интервала динамического наблюдения за пациентами, имевшими в анамнезе НА после низких передних резекций прямой кишки, не оправдано

Экспериментальное обоснование возможности применения нового имплантата для поддержания объема шлеммова канала при глаукоме

PURPOSE: To develop an optimal device of our own design to expand and maintain Schlemm's canal volume and experimentally assess its application in practice. METHODS: To conduct the study we selected an equiatomic alloy composition of nickel and titanium - Nitinol. The implant is a hollow tube with multiple perforations of different sizes. Its outer diameter is 245 mkm, internal -150 mkm. Implant is shaped like an open ring with a diameter of 11 mm. We used Glaucolight for Schlemm's canal probing. The study of technical possibilities presented by the stent implantation was performed on two enucleated eyes with terminal glaucoma without previous surgery. NDPS was performed followed by probing and drainage implantation. RESULTS: During an attempt to implant the drainage as a whole ring we encountered difficulties that could be attributed to nitinol rigidity, residual septs inside Schlemm's canal, and the drainage insertion into collecting channel opening. In this case the ring was divided into two segments, which were implanted into the nasal and temporal side of the sinus venosus, starting from sclerectomy zone. In the experiment, there were no false passage formation, trabecular meshwork rupture and Descemet's membrane detachment. Macropreparations study revealed no damage through the trabecular meshwork and Descemet's membrane defects. In all cases, the whole implant was located in the Schlemm's canal lumen. Ultrasound biomicroscopy in both eyes revealed a correct placement of the implant throughout the channel. CONCLUSION: The experiment confirmed a possibility of NiTi drainage implantation into eyes with terminal glaucoma, with no previous surgical or conservative treatment. Stent implantation is possible after preliminary viscocanalostomy and Schlemm's canal probing. The findings may serve as a basis for further clinical trials to optimize glaucoma surgical treatment.ЦЕЛЬ. Разработка оптимального устройства собственной конструкции для расширения и поддержания объема шлеммова канала и оценка возможности его применения в эксперименте. МЕТОДЫ. Для проведения исследования выбран сплав эквиатомного состава никеля и титана - нитинол. Имплантат представляет собой полую трубку с многочисленными перфорациями различной площади. Его внешний диаметр составляет 245 мкм, внутренний -150 мкм. Имплантату придана форма разомкнутого кольца диаметром 11 мм. В качестве инструмента для бужирования шлеммова канала использовали изделие Glaucolight. Изучение технической возможности имплантации представленного стента выполнено на двух энуклеированных глазах с терминальной глаукомой без предшествующих хирургических вмешательств. Выполняли непроникающую глубокую склерэктомию (НГСЭ) с дальнейшим бужированием и имплантацией дренажа. РЕЗУЛЬТАТЫ. В ходе имплантации стента выявлены трудности при его введении в виде целого кольца, что, возможно, связано с ригидностью нитинола, наличием остаточных септ внутри шлеммова канала, попаданием изделия в устье коллекторного канальца. В этом случае кольцо делилось на два сегмента, которые последовательно имплантировали в носовую и височную части венозного синуса, начиная от зоны склерэктомии. В ходе эксперимента не было формирования ложного хода, разрыва трабекулярной сети, отслойки десцеметовой оболочки. Изучение макропрепарата выявило отсутствие сквозных повреждений трабекулярной сети и дефектов в десцеметовой мембране. Во всех случаях имплантат полностью находился в просвете шлеммова канала. Ультразвуковая биомикроскопия на двух глазах выявила правильное положение имплантата на всем протяжении канала. ЗАКЛЮЧЕНИЕ. В эксперименте доказана возможность имплантации дренажа из никелида титана предложенной нами конструкции при терминальной глаукоме на глазах, в которых ранее не выполнялось хирургическое вмешательство и не проводилось медикаментозное лечение. Имплантация стента возможна после предварительной вискоканалостомии и бужирования шлеммова канала. Полученные данные являются основой для проведения дальнейших клинических исследований по оптимизации методов хирургического лечения глаукомы

Diagnosis and Treatment of Irritable Bowel Syndrome: Clinical Recommendations of the Russian Gastroenterological Association and Association of Coloproctologists of Russia

Aim. Current clinical recommendations accentuate current methods for the diagnosis and treatment of irritable bowel syndrome (IBS).Key points. IBS is a functional bowel disorder manifested with recurrent, at least weekly, abdominal pain with the following attributes (any two leastwise): link to defecation, its frequency or stool shape. The symptoms are expected to persist for at minimum three months in a total six-month follow-up. Similar to other functional gastrointestinal (GI) disorders, IBS can be diagnosed basing on the patient symptoms compliance with Rome IV criteria, provided the absence of potentially symptom-causative organic GI diseases. Due to challenging differential diagnosis, IBS can be appropriately established per exclusionem, with pre-examination as follows: general and biochemical blood tests; tissue transglutaminase IgA/IgG antibody tests; thyroid hormones test; faecal occult blood test; hydrogen glucose/ lactulose breath test for bacterial overgrowth; stool test for enteric bacterial pathogens and Clostridium difficile A/B toxins; stool calprotectin test; abdominal ultrasound; OGDS, with biopsy as appropriate; colonoscopy with biopsy. The IBS sequence is typically wavelike, with alternating remissions and exacerbations often triggered by psychoemotional stress. Treatment of IBS patients includes dietary and lifestyle adjustments, various-class drug agents prescription and psychotherapeutic measures.Conclusion. Adherence to clinical recommendations can facilitate timely diagnosis and improve medical aid quality in patients with different clinical IBS variants

Diagnosis and Treatment of Irritable Bowel Syndrome: Clinical Recommendations of the Russian Gastroenterological Association and Association of Coloproctologists of Russia

Aim. Current clinical recommendations accentuate current methods for the diagnosis and treatment of irritable bowel syndrome (IBS).Key points. IBS is a functional bowel disorder manifested with recurrent, at least weekly, abdominal pain with the following attributes (any two leastwise): link to defecation, its frequency or stool shape. The symptoms are expected to persist for at minimum three months in a total six-month follow-up. Similar to other functional gastrointestinal (GI) disorders, IBS can be diagnosed basing on the patient symptoms compliance with Rome IV criteria, provided the absence of potentially symptom-causative organic GI diseases. Due to challenging differential diagnosis, IBS can be appropriately established per exclusionem, with pre-examination as follows: general and biochemical blood tests; tissue transglutaminase IgA/IgG antibody tests; thyroid hormones test; faecal occult blood test; hydrogen glucose/ lactulose breath test for bacterial overgrowth; stool test for enteric bacterial pathogens and Clostridium difficile A/B toxins; stool calprotectin test; abdominal ultrasound; OGDS, with biopsy as appropriate; colonoscopy with biopsy. The IBS sequence is typically wavelike, with alternating remissions and exacerbations often triggered by psychoemotional stress. Treatment of IBS patients includes dietary and lifestyle adjustments, various-class drug agents prescription and psychotherapeutic measures.Conclusion. Adherence to clinical recommendations can facilitate timely diagnosis and improve medical aid quality in patients with different clinical IBS variants