387 research outputs found
Обилие, видовое разнообразие и структура сообщества метазойного микрозоопланктона в градиенте бухта — взморье (на примере Севастопольской бухты, Чёрное море)
Цель исследования — выявить закономерные изменения в обилии, видовом разнообразии и структуре сообществ метазойного микрозоопланктона (ММ) в градиентных условиях морского прибрежья на относительно небольших пространственных масштабах. Актуальность работы определяется малочисленностью подобных исследований, позволяющих опосредованно оценить степень антропогенного воздействия на морскую биоту и установить трофический статус локальных акваторий с помощью индексов видового разнообразия. Проанализированы три акватории прибрежья города Севастополя: открытое взморье, устье Севастопольской бухты и внутренняя её часть. Локализация станций отбора проб отражает градиент условий среды, характеризующийся разной степенью воздействия на биоту природных и антропогенных факторов. Исследования проведены в летний и осенний периоды года. Пробы ММ отбирали из трёх горизонтов водного столба — поверхностного, 0–5-метрового и 0–10-метрового слоёв. В открытом взморье и устье бухты численность ММ по вертикали была более выравненной, тогда как в глубине бухты различия между слоями могли достигать 5–700 раз. Максимальная численность ММ (1837,1 тыс. экз.·м−3) отмечена в начале августа в поверхностном слое во внутренней части бухты. С конца лета происходило снижение обилия во всех исследованных акваториях. Видовое разнообразие сообщества ММ, оценённое с помощью индексов Шеннона, Симпсона, Пиелу и др., уменьшалось в направлении от открытого взморья вглубь бухты. Эта закономерность сохранялась в оба сезона. Наиболее информативными оказались индекс Шеннона, индекс полидоминантности Симпсона и индекс выравненности Пиелу. Они хорошо отражали как сезонные изменения видового разнообразия, так и направленность изменений в градиенте трофности локальных акваторий бухты. С помощью многомерного анализа выявлены случаи существенной трансформации в структуре сообщества ММ придонного слоя вод в глубине бухты. Основной вероятной причиной этих локальных изменений является возникновение в загрязнённых участках бухты гипоксийных условий в нижних горизонтах вод, приводящее к деградации численности и видового состава исследуемого зоопланктонного сообщества
Interior regularity criteria for suitable weak solutions of the Navier-Stokes equations
We present new interior regularity criteria for suitable weak solutions of
the 3-D Navier-Stokes equations: a suitable weak solution is regular near an
interior point if either the scaled -norm of the velocity
with , , or the -norm of the
vorticity with , , or the
-norm of the gradient of the vorticity with , , , is sufficiently small near
Ultra-Mini Percutaneous Nephrolithotripsy and Retrograde Intrarenal Surgery in Treatment of Less than 2 cm Kidney Stones: Comparative Efficacy and Safety
Background. Renal stones of ≤ 2cm size occur most commonly, with several treatment options currently available that include remote shockwave lithotripsy, percutaneous nephrolithotripsy (PCNL) and retrograde intrarenal surgery (RIRS). The choice of treatment for ≤ 2 cm kidney stones remains a relevant and hotly debated issue.Aim. A study of the efficacy, safety, advantages and disadvantages of ultra-mini percutaneous nephrolithotripsy (ultra-mini PCNL) and retrograde intrarenal surgery (RIRS) in treatment of ≤ 2 cm kidney stones.Materials and methods. Treatment outcomes in urology patients of the Botkin Hospital were analysed retrospectively for years 2017–2022. The patients were divided between cohorts: cohort 1 consisted of patients who underwent ultra-mini PCNL; cohort 2 included 41 patients with RIRS.Results and discussion. The incidence of complete stone absence on the day after surgery was significantly higher in cohort 1 (39; 92.8 %) vs. 2 (33; 80.4 %). Mean operation time was significantly less in cohort 1 (55 [30–80] min) vs. 2 (78 [30–125] min). Mean hospital stay did not differ significantly between the cohorts: 3 (1–5) vs. 2.8 (2–4) days in cohorts 1 and 2, respectively. Haematuria was statistically more severe in cohort 1 (7 cases; 16.6 %) vs. 2 (4 cases; 9.7 %); mean postoperative haemoglobin decrease was also significantly higher in cohort 1 (11.6) vs. 2 (6.4 g/L).Conclusion. Both ultra-mini PCNL and RIRS are effective, safe and complementary procedures in treatment for ≤2 cm renal stones. Ultra-mini PCNL is more effective over RIRS in terms of single-intervention complete stone removal and shorter operation time, whereas the overall complications rate did not significantly differ between cohorts
"Flora of Russia" on iNaturalist: a dataset
The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people were involved in the data collection. Within 20 months, the participants accumulated 750,143 photo observations of 6,857 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flor
Absence of an N-Linked Glycosylation Motif in the Glycoprotein of the Live-Attenuated Argentine Hemorrhagic Fever Vaccine, Candid #1, Results in Its Improper Processing, and Reduced Surface Expression
Adaptive X-ray Optical Elements Based on Longitudinal and Transverse Acoustic Waves in the KHz and MHz Frequency Ranges
Glycosylation Affects JUNV GPC Trafficking
Junin virus (JUNV), a highly pathogenic New World arenavirus, is the causative agent of Argentine hemorrhagic fever (AHF). The live-attenuated Candid #1 (Can) strain currently serves as a vaccine for at-risk populations. We have previously shown that the Can glycoprotein (GPC) gene is the primary gene responsible for attenuation in a guinea pig model of AHF. However, the mechanisms through which the GPC contributes to the attenuation of the Can strain remain unknown. A more complete understanding of the mechanisms underlying the attenuation and immunogenicity of the Can strain will potentially allow for the rational design of additional safe and novel vaccines. Here, we provide a detailed comparison of both RNA and protein expression profiles between both inter- and intra-segment chimeric JUNV recombinant clones expressing combinations of genes from the Can strain and the pathogenic Romero (Rom) strain. The recombinant viruses that express Can GPC, which were shown to be attenuated in guinea pigs, displayed different RNA levels and GPC processing patterns as determined by Northern and Western blot analyses, respectively. Analysis of recombinant viruses containing amino acid substitutions selected at different mouse brain passages during the generation of Can revealed that altered Can GPC processing was primarily due to the T168A substitution within G1, which eliminates an N-linked glycosylation motif. Incorporation of the T168A substitution in the Rom GPC resulted in a Can-like processing pattern of Rom GPC. In addition, JUNV GPCs containing T168A substitution were retained within the endoplasmic reticulum (ER) and displayed significantly lower cell surface expression than wild-type Rom GPC. Interestingly, the reversion A168T in Can GPC significantly increased GPC expression at the cell surface. Our results demonstrate that recombinant JUNV (rJUNV) expressing Can GPC display markedly different protein expression and elevated genomic RNA expression when compared to viruses expressing Rom GPC. Additionally, our findings indicate that the N-linked glycosylation motif at amino acid positions 166–168 is important for trafficking of JUNV GPC to the cell surface, and the elimination of this motif interferes with the GPC release from the ER
ROLE OF TUMOR NECROSIS FACTOR ALPHA IN IMMUNE PATHOGENESIS OF DIFFERENT DISEASES AND ITS SIGNIFICANCE FOR EVOLVING ANTICYTOKINE THERAPY WITH MONOCLONAL ANTIBODIES
Tumor necrosis factor alpha (generally known as cachectin) was noted as a hallmark since the time of its discovery and still retains its position as one of the most intensely studied molecules in the field of biomedicine. TNFα is considered a prototype molecule of the family which, on the one hand, plays an important role in regulating normal differentiation, growth and metabolism of various cells, and on the other hand, acts as mediator of inflammatory processes in various human diseases. Intensive interdisciplinary studies of TNFα biological role and therapeutic use have led to understanding of its polyfunctional effects and establishment of its leading role in immune pathogenesis of diseases, which was the basis for the development of “anticytokine” therapy with highly specific monoclonal antibodies. We aimed for a search of literature in the field of studying TNFα structure and properties, its role under normal conditions, in different diseases and therapy. The literature studies were performed using scientific searching systems and databases. The results are as follows: the role of tumor necrosis factor-α (TNFα) in human body in normal and pathological state was considered. Possible TNF-inducible signaling pathways, as well as existing inhibitors based on monoclonal antibodies for the treatment of rheumatoid arthritis and other autoimmune diseases are described. In conclusion, intensive interdisciplinary studies of TNFα biological functions in normal state and diseases are still relevant today, despite huge knowledge gained on this subject.Undisputable progress in understanding the functional multiplicity of TNFα as a participant in regulation of various physiological and pathological processes in the human body has promoted development of biological agents, i.e., the tumor necrosis factor inhibitors based on monoclonal antibodies, which proved to be highly effective drugs for treatment of rheumatoid arthritis and other diseases, thus being effective and safe biopharmaceuticals
Synthesis of technetium hydride TcH at 27 GPa
In this work, we synthesize and investigate lower technetium hydrides at
pressures up to 45 GPa using the synchrotron X-ray diffraction, reflectance
spectroscopy, and ab initio calculations. In the Tc-H system, the hydrogen
content in TcH phases increases when the pressure rises, and at 27 GPa we
found a new hexagonal (hcp) nonstoichiometric hydride TcH. The
formation of technetium hydrides is also confirmed by the emergence of a new
reflective band at 450-600 nm in the reflectance spectra of TcH samples
synthesized at 45 GPa. On the basis of the theoretical analysis, we proposed
crystal structures for the TcH (TcH) and
TcH (TcH) phases previously obtained at 1-2 GPa. The
calculations of the electron-phonon interaction show that technetium hydrides
TcH do not possess superconducting properties due to the low
electron-phonon interaction parameter ()
Модели-полиады и их применение в обучении математике
Considered systems of models, called models-polyads. Components of the model-polyads are various models of a prototype object, describing the same its properties, and the exchange of information between the components of the modelpolyads occurring without distorting the information. The examples of modelspolyads, in particular, shows that in the form of models-polyads are the algebra of geometric vectors, algebra of complex numbers, etc. There are highlights the benefits of studying the objects in the form of models-polyads, and especially in the case of training, when the objects under study are presented in a models-polyads.Рассматриваются системы моделей, называемые моделями-полиадами. Компонентами модели-полиады (в частности, модели-диады, модели-триады) являются различные модели некоторого объекта- прототипа, описывающие одни и те же его особенности, причем обмен информацией между компонентами модели-полиады, происходящий без искажения этой информации. Приведены примеры моделей-полиад, в частности, показано, что в виде моделей-полиад представлены векторная алгебра, алгебра комплексных чисел и др. Выделены преимущества изучения объектов, представленных в виде моделей-полиад, и особенности обучения в случае, когда изучаемые объекты представлены в виде моделей-полиад
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