Collision of viscoelastic bodies: Rigorous derivation of dissipative force

We report a new theory of dissipative forces acting between colliding viscoelastic bodies. The impact velocity is assumed not to be large, to avoid plastic deformations and fragmentation at the impact. The bodies may be of an arbitrary convex shape and of different materials. We develop a mathematically rigorous perturbation scheme to solve the continuum mechanics equation that deals with both displacement and displacement rate fields and accounts for the dissipation in the bulk of the material. The perturbative solution of this equation allows to go beyond the previously used quasi-static approximation and obtain the dissipative force. This force does not suffer from the physical inconsistencies of the latter approximation and depends on particle deformation and deformation rate.Comment: 9 pages, 1 figure. arXiv admin note: text overlap with arXiv:1410.328

Deep Photometry of GRB 041006 Afterglow: Hypernova Bump at Redshift z=0.716

We present deep optical photometry of the afterglow of gamma-ray burst (GRB) 041006 and its associated hypernova obtained over 65 days after detection (55 R-band epochs on 10 different nights). Our early data (t<4 days) joined with published GCN data indicates a steepening decay, approaching F_nu ~t^{-0.6} at early times (<<1 day) and F_nu ~t^{-1.3} at late times. The break at t_b=0.16+-0.04 days is the earliest reported jet break among all GRB afterglows. During our first night, we obtained 39 exposures spanning 2.15 hours from 0.62 to 0.71 days after the burst that reveal a smooth afterglow, with an rms deviation of 0.024 mag from the local power-law fit, consistent with photometric errors. After t~4 days, the decay slows considerably, and the light curve remains approximately flat at R~24 mag for a month before decaying by another magnitude to reach R~25 mag two months after the burst. This ``bump'' is well-fitted by a k-corrected light curve of SN1998bw, but only if stretched by a factor of 1.38 in time. In comparison with the other GRB-related SNe bumps, GRB 041006 stakes out new parameter space for GRB/SNe, with a very bright and significantly stretched late-time SN light curve. Within a small sample of fairly well observed GRB/SN bumps, we see a hint of a possible correlation between their peak luminosity and their ``stretch factor'', broadly similar to the well-studied Phillips relation for the type Ia supernovae.Comment: ApJ Letters, accepted. Additional material available at ftp://cfa-ftp.harvard.edu/pub/kstanek/GRB041006

Utilization of Immunoblotting in Studies of Epitope Targeting in Monoclonal Antibodies to Melioidosis Agent Antigen 200 kDa

Objective of the research was to use immunoblotting for studies of epitope targeting in monoclonal antibodies to 200 kDa Burkholderia pseudomallei antigen, which are synthesized by hybridomas-producers from the two collections in the laboratory of immunodiagnostics and biotechnology at the premises of Volgograd Research Anti-Plague Institute. Employed were 8 typical strains of melioidosis agent with the complete antigenic structure. Antigen preparations were separated by means of denaturating vertical electrophoresis in 12 % polyacrylamide gel with 0.1 % sodium dodecylsulfate. During the process of cell-replication, 12 hybridomas-producers were given preparative amounts of monoclonal antibodies to 200 kDa Burkholderia pseudomallei glycoprotein. Following that, immunoperoxidase conjugates were manufactured. Epitope targeting of monoclonal antibodies was evaluated using immunoblotting. With the help of vertical electrophoresis identified was the presence of several mandatory major components contained in the antigen complexes of the salt-water and formamid B. pseudomallei extracts . Differential staining substantiated glycoprotein origin of certain antigen components. Immunoblotting with the stated above antigen preparations revealed epitope targeting of a number of monoclonal antibodies to 200 kDa antigen of melioidosis agent; demonstrated were the differences in their specific interaction with biopolymers which form part of the antigen specter. Those differences were characteristic of hybridomas-producers belonging to different collections, as well as of particular strains of B. pseudomallei

The Image of Artificial Intelligence in Cinema: Transformations in the 1980s‑2010s

Статья посвящена актуальной теме образа искусственного интеллекта в кинематографе как осмысления отношения к внедрению высоких технологий в жизнь человека и как средства осмысления человеком не только искусственного интеллекта, но и самого себя. В качестве репрезентативных этапов авторами выбраны исторические периоды 1980–1990-х, 2000-х и 2010-х гг. Методологической основой исследования выступил и философско-искусствоведческий и сравнительный анализ кинофильмов. В качестве материала для исследования выбраны популярные в свое время и ставшие классикой киноленты: «Бегущий по лезвию» (Р. Скотт, 1981 г.), «Призрак в доспехах» (М. Осии, 1995 г.), «Искусственный разум» (С. Спилберг, 2001), «Прометей» (Р. Скотт, 2012), «Чужой: Завет» (Р. Скотт, 2017). Исследование показывает, что основными вопросами, которые поднимает кинематограф 1980–2010-х гг. в связи с образом искусственного интеллекта, можно назвать вопросы взаимодействия человека и созданного им андроида, характера их отношений, возможного равенства. Кинорепрезентанты демонстрируют актуальность тем степени признания человечности антропоморфного робота, его самосознания, статуса в человеческом обществе, этики отношений людей и машин. Образ искусственного интеллекта развивается от представлений о нем как о во многом равном человеку к репрезентации его как угрозы для положения человека в миреThe article is devoted to the actual topic of the image of artificial intelligence in cinematography as an understanding of the attitude to the introduction of high technologies in human life and as a means of understanding not only artificial intelligence, but also oneself. The historical periods of the 1980s – 1990s, 2000s and 2010s are chosen as representative stages. The methodological basis of the study was also a philosophical, art history and comparative analysis of films. As a material for the study, films that were popular in their time and became classics were chosen: «Blade Runner» (R. Scott, 1981), «Ghost in the Shell» (M. Oshii, 1995), «Artificial Intelligence» (S. Spielberg, 2001), «Prometheus» (R. Scott, 2012), «Alien: Covenant» (R. Scott, 2017). The study shows that the main questions that the cinema of the 1980s‑2010s raises in connection with the image of artificial intelligence can be called the issues of interaction between a person and the android he created, the nature of their relationship, and possible equality. Film representatives demonstrate the relevance of the degree of recognition of the humanity of an anthropomorphic robot, its self-awareness, status in human society, and the ethics of relations between people and machines. The image of artificial intelligence is developing from ideas about it as in many respects equal to a person to its representation as a threat to the position of a person in the worl

СОВЕРШЕНСТВОВАНИЕ ГЕНОТИПИРОВАНИЯ ШТАММОВ B. PERTUSSIS

The new rapid molecular genotyping method was developed for studying the structure of ptxP promoter of pertussis toxin. Method is based on PCR-RFLP analysis, which allows studying the specific restriction profiles of the B. pertussis strains and allows differentiation of the strains with the ptxP structural particularities. The developed method for genotyping of strains of B. pertussis can be hhelpful when monitoring strains of the causative agent of whooping cough in system of an epidemiological surveillance over pertussis infections, allowing observation over circulating population of B.pertussis, revealing strains of the causative agent of whooping cough with high production of pertussis toxin and to watch their distribution.Разработан новый ускоренный молекулярно-генетический способ типирования штаммов B. pertussis по структуре ptxP промотора коклюшного токсина. Метод основан на ПЦР-ПДРФ анализе, который позволяет получить характерный рестрикционный профиль и дает возможность дифференцировать штаммы с особенностями структуры промотора ptxP. Разработанный метод типирования штаммов B. pertussis может являться инструментом при мониторинге штаммов возбудителя коклюша в системе эпидемиологического надзора за коклюшной инфекций, позволяющим проводить наблюдение за циркулирующей популяцией B. pertussis, выявлять высоковирулентные штаммы возбудителя коклюша и следить за их распространением

Characterization of toxigenic Corynebacterium diphtheriae strains isolated in Russia

The aim of the study was to characterize toxigenic strains of Corynebacterium diphtheriae by examining 12 toxigenic strains of C. diphtheriae isolated in Russia between January, 2017 to June, 2019. The morphological, toxigenic and biochemical properties of C. diphtheriae was studied. Genotyping of C. diphtheriae strains was performed using MLST and dtxR gene sequencing with subsequent phylogenetic analysis. Results. Toxigenic strains of C. diphtheriae were isolated in the Novosibirsk, Samara and Chelyabinsk Regions, the Khanty-Mansi Autonomous Okrug — Yugra as well as the Republic of Northern Ossetia — Alania. Among these strains, 5 were isolated from diphtheria patients (moderate disease found in one case, mild course — remaining patients) and 7 strains were isolated from bacterial carriers. In two cases C. diphtheriae from diphtheria patients were identified as ST25 sequence type, gravis variant; in one case — ST8 type, gravis variant; two cases — ST67 sequence type, mitis variant. In asymptomatic carriers of tox-positive C. diphtheriae strains they belonged to ST25 sequence type, gravis variant — in two cases, ST67 type, mitis variant — in four cases. A sequencing type was not identified in one case. All sequence types were widespread globally being presented by a large number of isolates in the PubMLST and characterized by a substantial amount of derivative sequence types. At the same time, they belonged to different clonal complexes and differed markedly from each other contributing to their reliable difference as assessed by MLST. Study of gene dtxR sequence diversity showed that all allelic variants were typical for the representatives of these sequence types. New alleles of gene dtxR were not revealed in strains examined. It was shown that non-synonymous substitution C440T leading to A147V amino acid substitution was found solely in one allele distributed in ST8, ST185, ST195 and ST451 types suggesting at late mutation. In contrast, the polymorphism C640A resulting in the amino acid substitution L214I was found not only in the same allele, but also in the basal tree branches indicating that isoleucine was in the ancestral sequence of the protein

Obtainment of Monoclonal Antibodies and Prospects of Their Application as Basis for Immunodiagnostic Aids for Crimean-Congo Hemorrhagic Fever Virus Detection

) as framework for the production of tools for CCHF virus detection and identification in artificially contaminated samples and clinical specimens containing CCHF antigens was proven efficient

Роль исследования уровня тиреоглобулина в смыве из пункционной иглы в диагностике метастазов в лимфатических узлах шеи при высокодифференцированном раке щитовидной железы

The study objective: to assess the diagnostic value of measuring the concentration of thyroglobulin (Tg) in the washout fluid of the fine needle aspiration (FNA) for the detection of well-differentiated thyroid cancer regional metastases.Material and Methods. The study included 64 patients with well-differentiated thyroid cancer. Ultrasound examination revealed 71 enlarged regional lymph nodes. The patients underwent simultaneous FNA cytology examination of lymph nodes and the study of Tg concentration in the washout fluid of the needle aspiration. Regional lymph node metastases were verified in 38 patients. These patients underwent surgery. Histological examination of surgical specimens was performed in 43 out of 71 cases.Results. The sensitivity, specificity, and accuracy of the FNA biopsy and the study of the concentration of thyroglobulin in the in the washout fluid of FNA were 88.5 %, 56.3 %, 76.2 % and 100 %, respectively. The rate of false-positive results of thyroid FNA biopsy was 16 %. The optimal cutoff value for FNA-Tg measurement was 4 g/ml. This made it possible to increase the sensitivity and specificity of the method to 100 %. It was found that the presence of circulating antibodies to Tg in the blood serum had no effect on the diagnostic value of FNA-Tg measurement (p=0.421). There were no statistically significant differences in the levels of thyroglobulin in the in the washout fluid of FNA between patients with Tg concentration above and below the cutoff values (3.9 [0.47; 39.9] ng/ ml vs 12.3 [0.57; 294.8] ng/ml). Цель исследования ‒ оценить информативность метода определения уровня тиреоглобулина в смыве из пункционной иглы в диагностике регионарных метастазов высокодифференцированного рака щитовидной железы.Материалы и методы. В исследование включено 64 больных высокодифференцированным раком щитовидной железы с интактной щитовидной железой и 71 регионарным лимфатическим узлом, визуализируемым по данным ультразвукового исследования. Пациентам одномоментно выполнены тонкоигольная аспирационная биопсия лимфатических узлов с последующим цитологическим исследованием и исследование уровня тиреоглобулина в смыве из пункционной иглы. По результатам верификации метастатического поражения 38 пациентам выполнено хирургическое вмешательство на первичном очаге и путях лимфатического оттока. Послеоперационное гистологическое исследование образцов проведено в 43 случаях из 71.Результаты. С помощью метода определения уровня тиреоглобулина в смыве из пункционной иглы были выявлены или исключены метастазы высокодифференцированного рака щитовидной железы. Чувствительность, специфичность, точность методов тонкоигольной аспирационной биопсии и исследования уровня тиреоглобулина в смыве из пункционной иглы составили 88,5; 56,3; 76,2 и 100 % соответственно. Количество ложноположительных результатов в отношении высокодифференцированного рака щитовидной железы по данным тонкоигольной аспирационной биопсии составило 16 %. Определено пороговое значение тиреоглобулина в смыве из пункционной иглы ‒ 7,4 нг/мл, позволяющее повысить чувствительность и специфичность метода до 100 %. Отмечено, что наличие циркулирующих антител к тиреоглобулину в сыворотке крови не влияет на информативность метода определения уровня тиреоглобулина в смыве из пункционной иглы (р=0,421). Не выявлено статистически значимых различий в значениях тиреоглобулина в смыве пункционной иглы между пациентами групп с АТ-ТГ выше и ниже референсных значений – 3,9 [0,47; 39,9] нг/мл против 12,3 [0,57; 294,8]

West Nile Fever: Results of Monitoring over the Causative Agent in the Russian Federation in 2021, the Incidence Forecast for 2022

The epidemiological situation on West Nile fever (WNF) in Russia in 2021 was characterized by an increase in the incidence relative to 2020 (more than 6-fold increase). The peculiarities of the WNF epidemic process have been determined: the territorial distribution of cases (75 % – in the constituent entities of the Central Federal District), the expansion of the causative agent’s areal with the involvement of new territories (official registration of cases in Moscow and the Tula Region for the first time ever), the early end of the epidemic season. An increase in the proportion of neuroinvasive forms, an increase in the share of male patients and the age group of 30–39 years, a decrease in the proportion of the population in contact with the pathogen in natural places of mass recreation were observed in the incidence structure. According to the results of the monitoring studies carried out by the Reference Center, intensive circulation of the pathogen was established on the territory of the Central Federal District, Southern Federal District, and the North Caucasian Federal District. The low reported incidence was due to insufficient detection of WNF patients. The results of moleculargenetic study showed that in the European part of Russia, WNV lineage 2 circulated in both epizootic and epidemic cycles, lineage 2 in the south of Western Siberia (Omsk Region) and lineage 4 in the Volgograd Region – in the epizootic cycle only. Phylogenetic analysis revealed that strains isolated from the Astrakhan, Volgograd, Rostov, Voronezh Regions and the Republic of Dagestan in 2021 belong to the genovariant of WNV lineage 2 not registered in Russia previously.  The topology of the phylogenetic tree indicates the possible African origin of the isolates, probably imported into Russia by migratory birds across the coast of the Caspian Sea. In the Volgograd Region, WNV of both the entrenched clade of lineage 2 (since 2007) and new genovariant circulated. The specialists of the Reference Center developed a forecast of WNF epidemiological situation development in the Volgograd Region in 2022 on the basis of the neural network modeling technique, according to which an increase in the incidence is expected, comparable to that in 2010 and 2012. Based on the climate projections, an increase in the incidence is possible in all Federal Districts of the European part of Russia, the southern territories of the Urals, Western Siberia, and the Far East