Expedition diary — insights into the history of organizing and conducting Russian Arctic expeditions in the early XXth century

The collections belonging to the Museum-Archive of the history of study and development of the European North of the Barents Center of the Humanities — Branch of the Federal Research Center «Kola Science Centre of the Russian Academy of Sciences» (BCH KSC RAS), contain several handwritten diaries by members of Arctic expeditions organized in the first half of the XXth century. The article discusses the value of the expedition diary of a member of a Russian Arctic expedition to Dikson Island (1916), the hydrometeorologist Innokenty Tikhomirov (1890–1955), as a possible source of data on the history of organizing and conducting scientific research in the Arctic. Based on the data presented in the diary, the paper reconstructs the progress of work on the organization of the northernmost meteorological station on Dikson Island in 1916.В фондах, принадлежащих Музею-архиву истории изучения и освоения Европейского Севера Центра гуманитарных проблем Баренц региона — филиала ФИЦ КНЦ РАН, хранятся несколько рукописных дневников, авторы которых в первой половине ХХ в. были участниками арктических экспедиций. В статье рассмотрен потенциал экспедиционного дневника участника российской экспедиции на о. Диксон (1916) гидрометеоролога и климатолога Иннокентия Константиновича Тихомирова (1890–1955) как возможного исторического источника по истории организации и проведения научных исследований в Арктике. Благодаря дневнику И. К. Тихомирова реконструирован ход работ по организации в 1916 г. самой северной на тот момент метеорологической станции на о. Диксон

A putative RNA-interference-based immune system in prokaryotes: computational analysis of the predicted enzymatic machinery, functional analogies with eukaryotic RNAi, and hypothetical mechanisms of action

BACKGROUND: All archaeal and many bacterial genomes contain Clustered Regularly Interspaced Short Palindrome Repeats (CRISPR) and variable arrays of the CRISPR-associated (cas) genes that have been previously implicated in a novel form of DNA repair on the basis of comparative analysis of their protein product sequences. However, the proximity of CRISPR and cas genes strongly suggests that they have related functions which is hard to reconcile with the repair hypothesis. RESULTS: The protein sequences of the numerous cas gene products were classified into ~25 distinct protein families; several new functional and structural predictions are described. Comparative-genomic analysis of CRISPR and cas genes leads to the hypothesis that the CRISPR-Cas system (CASS) is a mechanism of defense against invading phages and plasmids that functions analogously to the eukaryotic RNA interference (RNAi) systems. Specific functional analogies are drawn between several components of CASS and proteins involved in eukaryotic RNAi, including the double-stranded RNA-specific helicase-nuclease (dicer), the endonuclease cleaving target mRNAs (slicer), and the RNA-dependent RNA polymerase. However, none of the CASS components is orthologous to its apparent eukaryotic functional counterpart. It is proposed that unique inserts of CRISPR, some of which are homologous to fragments of bacteriophage and plasmid genes, function as prokaryotic siRNAs (psiRNA), by base-pairing with the target mRNAs and promoting their degradation or translation shutdown. Specific hypothetical schemes are developed for the functioning of the predicted prokaryotic siRNA system and for the formation of new CRISPR units with unique inserts encoding psiRNA conferring immunity to the respective newly encountered phages or plasmids. The unique inserts in CRISPR show virtually no similarity even between closely related bacterial strains which suggests their rapid turnover, on evolutionary scale. Corollaries of this finding are that, even among closely related prokaryotes, the most commonly encountered phages and plasmids are different and/or that the dominant phages and plasmids turn over rapidly. CONCLUSION: We proposed previously that Cas proteins comprise a novel DNA repair system. The association of the cas genes with CRISPR and, especially, the presence, in CRISPR units, of unique inserts homologous to phage and plasmid genes make us abandon this hypothesis. It appears most likely that CASS is a prokaryotic system of defense against phages and plasmids that functions via the RNAi mechanism. The functioning of this system seems to involve integration of fragments of foreign genes into archaeal and bacterial chromosomes yielding heritable immunity to the respective agents. However, it appears that this inheritance is extremely unstable on the evolutionary scale such that the repertoires of unique psiRNAs are completely replaced even in closely related prokaryotes, presumably, in response to rapidly changing repertoires of dominant phages and plasmids. This article was reviewed by: Eric Bapteste, Patrick Forterre, and Martijn Huynen. OPEN PEER REVIEW: Reviewed by Eric Bapteste, Patrick Forterre, and Martijn Huynen. For the full reviews, please go to the Reviewers' comments section

Development of electrochemical sensor based on aptamer specific to lung cancer tumor marker

Electrochemical aptasensor is a sensor based on an indicator electrode covered with a layer of an aptamer that is able to bind target molecules with high specificity. In this work, DNA-aptamer LC-2108 specific to lung cancer tumor marker was immobilized onto the surface of golden screen-printed and disc electrodes. The electrodes were studied by conventional electrochemical methods–cyclic voltammetry and electrochemical impedance spectroscopy. The current increase and electron transfer resistance decrease were registered. It seems as if the aptamer presence facilitated the electron transfer through the electrode-solution boundary. As the possible reasons of such an unusual electrochemical behavior we proposed the unordinary or irregular structure of the aptamer layer on the Au surface or the specific electrochemical properties of the aptamer itself

Сегментация временных рядов для выделения шаблонов в больших массивах данных

В работе представлен обзор методов обнаружения разладки для стационарных и нестационарных временных рядов. Целью работы является поиск разладки временного ряда в режиме реального времени. В качестве метода обнаружения разладки была выбрана модификация Воробейчикова на метода кумулятивных сумм. Также реализована сегментация на основе обнаруженных разладок.The work presents an overview of the methods for detecting disorder for stationary and non-stationary time series. The purpose of the work is to find the time series disorders in real time. The modification of Vorobeychikov, which based on method of cumulative sums was chosen as a method for detecting the disorder. Also implemented segmentation based on detected disorders

Неогегельянство Александра Кожева и его влияние на постмодернизм

The article discusses the main aspects of Alexandre Kojève's philosophy as well as the reception of his ideas in the philosophy of "Low materialism" (G. Bataille) and Postmodernism (M. Foucault, R. Barthes, B. Groys).The most important moments of Kojève's biography are noted and analyzed, especially his reinterpretation of Hegel’s dialectics, which had become one of the leading concepts of French philosophy of XX century. Moreover, there is a classification of the concepts of Hegelian dialectics, which Kojève uses as his Neohegelian language: Negative dialectics, Lord–bondsman dialectics, The End of History. Apart from this, there are some themes of Postmodern philosophy (The death of the subject) that are analyzed in comparative way with Kojève's ideas. The authors come to the conclusion that Kojève's innovative interpretation of "Phänomenologie des Geistes" had become one of the most important bases of Postmodernism.В статье рассматриваются основные аспекты философии А. Кожева, и рецепция его идей в философии «низкого материализма» (Ж. Батай) и постмодернизма (М. Фуко, Р. Барт, Б. Гройс). Отмечаются и анализируются некоторые моменты в биографии Кожева, в особенности, его увлечение Гегелем, трактовка которого впоследствии стала одной из ведущих концепций французской философской мысли. Анализируется классификация понятий гегелевской диалектики, являющейся инструментом и языком неогегельянства А. Кожева (негативная диалектика, диалектика раба и господина, конец истории), а также основные темы философии постмодернизма (смерть субъекта). Авторы приходят к выводу, что оригинальная трактовка А. Кожевом «Феноменологии духа» Гегеля стала одним из важнейших базисов философии постмодерна

Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid

The basic mechanisms of pulsed laser ablation in liquids (PLAL) as a method for the synthesis of nanoparticles (NPs) were considered. Physical and chemical processes occurring during the PLAL that determine the formation, composition and structure of the nanoparticles obtained are described. The influence of the composition and properties of the target material, the solvent and the characteristics of the laser irradiation on the efficiency of the synthesis of nanoparticles is discussed. Separately, an influence of the absorption and scattering (including nonlinear) of laser radiation in the dispersion of nanoparticles on the primary synthetic processes and secondary transformations inside the colloidal solution is examined. The specificity of the characterization of the colloidal solutions of oxide particles produced by PLAL is highlighted. The most promising practical applications of nanomaterials obtained are identified and the examples of their successful use in catalytic research and biomedicine are provided

Visualization of nanoconstructions with DNA-Aptamers for targeted molecules binding on the surface of screen-printed electrodes

Nanoconstructions of gold nanoparticles (NPs) obtained via pulsed laser ablation in liquid with DNA-aptamer specific to protein tumor marker were visualized on the surface of screen-printed electrode using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). AuNPs/aptamer nanoconstuctions distribution on the solid surface was studied. More uniform coverage of the carbon electrode surface with the nanoconstuctions was showed in comparison with DNA-aptamer alone on the golden electrode surface. Targeted binding of the tumor marker molecules with the AuNPs/DNA-aptamer nanoconstuctions was approved

Investigation of the effect of copper addition on physical and mechanical properties of TiNi-Cu porous alloy

This work is devoted to the physical and mechanical properties of porous alloys based on TiNi alloyed with different amounts of Cu additive. We show that by doping a porous TiNi alloy with copper instead of nickel, it is possible to obtain characteristics acceptable for use in implantology and superior to those of known porous TiNi alloys. Cu addition in the range from 1 to 10 at.% is shown to optimize the properties of tested alloys. There is a decrease in the minimal martensitic transformation stress τminMs from 37 to 17 MPa when compared to initial unalloyed TiNi. Alloys with 3 and 6 at.% of Cu are found to be optimal for use in medical practice. Along with a wide temperature range of reversible deformations that cover the range of operating temperatures (273–313 K), such alloys demonstrate their martensitic transformation stress values below 28 MPs. This permits to model implantable structures of complex configuration from such materials under a certain temperature regime

Preparation of porous TiNi-Ti alloy by diffusion sintering method and study of its composition, structure and martensitic transformations

The study demonstrates a method for controlling not only the phase composition but also the atomic composition of TiNi matrix in porous TiNi-Ti alloys developed for biomedical uses as implants. The alloys were obtained from TiNi powder which was sintered with Ti powder added at as much as 0–10 at%. The structure, phase and chemical composition of the produced TiNi-Ti alloys was investigated with respect to the amount of Ti added into the material. It is shown that in the sintered product containing 5 at% and more of Ti additive, the composition of its TiNi matrix becomes close to equiatomic (with Ti:Ni atomic ratio ~1), and the excessive Ti precipitates as secondary phases Ti2Ni and Ti3Ni4. In parallel, with increase in Ti ad- ditive from 0–10 at%, the structure of the precipitating Ti2Ni type phases changes its morphology from separate spherical or pyramidal precipitates to large dendritic formations. The direct martensitic trans- formation from austenite to martensite in all the samples was found to proceed in two stages and through the R-phase (B2→R→B19′). Thermoresistive analysis demonstrated that TiNi-Ti samples with 5 and more at% of Ti had their characteristic starting temperature of martensite transition stabilizing at ~57 °C (330 K). This implies that the sample with 5 at% of Ti additive exhibited desired martensite transition temperatures, while containing a minimum concentration of secondary-phase precipitates in its matrix which deteriorate its properties. Thus, for the 곙rst time, we show that a very simple preparation approach based on sintering powders of TiNi and Ti is capable of producing porous TiNi-Ti alloys with properties optimized for fabricating bone implants