261 research outputs found

    Solving the difference initial-boundary value problems by the operator exponential method

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    We suggest a modification of the operator exponential method for the numerical solving the difference linear initial boundary value problems. The scheme is based on the representation of the difference operator for given boundary conditions as the perturbation of the same operator for periodic ones. We analyze the error, stability and efficiency of the scheme for a model example of the one-dimensional operator of second difference

    Tah1 helix-swap dimerization prevents mixed Hsp90 co-chaperone complexes

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    Specific co-chaperone adaptors facilitate the recruitment of client proteins to the Hsp90 system. Tah1 binds the C-terminal conserved MEEVD motif of Hsp90, thus linking an eclectic set of client proteins to the R2TP complex for their assembly and regulation by Hsp90. Rather than the normal complement of seven α-helices seen in other tetratricopeptide repeat (TPR) domains, Tah1 unusually consists of the first five only. Consequently, the methionine of the MEEVD peptide remains exposed to solvent when bound by Tah1. In solution Tah1 appears to be predominantly monomeric, and recent structures have failed to explain how Tah1 appears to prevent the formation of mixed TPR domain-containing complexes such as Cpr6-(Hsp90)2-Tah1. To understand this further, the crystal structure of Tah1 in complex with the MEEVD peptide of Hsp90 was determined, which shows a helix swap involving the fifth α-helix between two adjacently bound Tah1 molecules. Dimerization of Tah1 restores the normal binding environment of the bound Hsp90 methionine residue by reconstituting a TPR binding site similar to that in seven-helix-containing TPR domain proteins. Dimerization also explains how other monomeric TPR-domain proteins are excluded from forming inappropriate mixed co-chaperone complexes

    The use of platelet-rich plasma in complex treatment of patients with gunshot wounds

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    На базі ВМКЦ ПР за період з жовтня 2014 р. по грудень 2015 р. у 60 хворих була застосована методика комплексного лікування вогнепальних ран з використанням збагаченої тромбоцитами пазми (ЗТП). Двічі на тиждень виконувалася перев’язка із ЗТП, отриманої із крові пацієнта. Застосування ЗТП привело до зменшення больового синдрому, появи ділянок активної грануляції, збільшення швидкості крайової епітелізації. Рани загоїлись у 100 % пацієнтів. У 5 % хворих застосування ЗТП не вплинуло на перебіг ранового процесу.Sixty wounded casualties have been treated using platelet-rich plasma (PRP) since October 2014 in Military Clinical Medical Center of the South region. Autologous PRP was applied twice a week. The results showed wound pain resolution, activation of wound bed granulation and marginal epithelization. 100% of wounds healed within 45 days on average. In 5% of cases the use of PRP did not influence wound process significantly. No complications were observed

    АВАРИЙНОЕ РЕАГИРОВАНИЕ УПРАВЛЕНИЯ РОСПОТРЕБНАДЗОРА ПО САХАЛИНСКОЙ ОБЛАСТИ В СВЯЗИ С АВАРИЕЙ НА АЭС «ФУКУСИМА-1»

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    The article describes the experience of the Administration of the Federal Service for Surveillance on Consumer Rights Protection and Human Well-being in Sakhalin Region in organizing prevention of conditions that endanger the public radiation safety related to the nuclear accident at the Fukushima nuclear power plant. The authors present results of the measurements of the radiation situation in the Sakhalin region and propose ways to improve organizational and sanitary-hygienic measures aimed on ensuring public protectiony in events of radiation accidents.В статье описан опыт организации деятельности Управления Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека по Сахалинской области по предупреждению условий, создающих угрозу радиационной безопасности населения, в связи с аварией на АЭС «Фукусима-1». Приведены результаты измерений параметров радиационной обстановки на территории Сахалинской области. Предложены пути совершенствования организационных и санитарно-гигиенических мероприятий, направленных на обеспечение безопасности населения, в случае возникновения радиационных аварий

    The Lsm2-8 complex determines nuclear localization of the spliceosomal U6 snRNA

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    Lsm proteins are ubiquitous, multifunctional proteins that are involved in the processing and/or turnover of many, if not all, RNAs in eukaryotes. They generally interact only transiently with their substrate RNAs, in keeping with their likely roles as RNA chaperones. The spliceosomal U6 snRNA is an exception, being stably associated with the Lsm2-8 complex. The U6 snRNA is generally considered to be intrinsically nuclear but the mechanism of its nuclear retention has not been demonstrated, although La protein has been implicated. We show here that the complete Lsm2-8 complex is required for nuclear accumulation of U6 snRNA in yeast. Therefore, just as Sm proteins effect nuclear localization of the other spliceosomal snRNPs, the Lsm proteins mediate U6 snRNP localization except that nuclear retention is the likely mechanism for the U6 snRNP. La protein, which binds only transiently to the nascent U6 transcript, has a smaller, apparently indirect, effect on U6 localization that is compatible with its proposed role as a chaperone in facilitating U6 snRNP assembly

    The mathematical simulation of the temperature fields of building envelopes under permanent frozen soil conditions

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    The physical-mathematical model of the thermal state of the aired technical underground taking into account the air exchange and design features of construction under permanent frozen soil conditions has been suggested. The computational scheme of the temperature fields prediction of building envelopes of projected buildings and soil under and nearby buildings has been developed. The numerical simulation of the temperature fields of building envelopes changes was conducted during a year. The results of the numerical simulation showed that the heat coming from the technical undergrounds and through the walls does not influence the temperature field of the soil neither under a building nor at a distance from it

    Experimental identification and analysis of macronuclear non-coding RNAs from the ciliate Tetrahymena thermophila

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    The ciliate Tetrahymena thermophila is an important eukaryotic model organism that has been used in pioneering studies of general phenomena, such as ribozymes, telomeres, chromatin structure and genome reorganization. Recent work has shown that Tetrahymena has many classes of small RNA molecules expressed during vegetative growth or sexual reorganization. In order to get an overview of medium-sized (40–500 nt) RNAs expressed from the Tetrahymena genome, we created a size-fractionated cDNA library from macronuclear RNA and analyzed 80 RNAs, most of which were previously unknown. The most abundant class was small nucleolar RNAs (snoRNAs), many of which are formed by an unusual maturation pathway. The modifications guided by the snoRNAs were analyzed bioinformatically and experimentally and many Tetrahymena-specific modifications were found, including several in an essential, but not conserved domain of ribosomal RNA. Of particular interest, we detected two methylations in the 5′-end of U6 small nuclear RNA (snRNA) that has an unusual structure in Tetrahymena. Further, we found a candidate for the first U8 outside metazoans, and an unusual U14 candidate. In addition, a number of candidates for new non-coding RNAs were characterized by expression analysis at different growth conditions

    The initial U3 snoRNA:pre-rRNA base pairing interaction required for pre-18S rRNA folding revealed by in vivo chemical probing

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    The synthesis of ribosomal subunits in the nucleolus is a conserved, essential process that results in cytoplasmic ribosomes with precisely processed and folded rRNAs assembled with ribosomal proteins. It has been proposed, but never directly demonstrated, that the U3 small nucleolar RNA (snoRNA), a nucleolar component required for ribosome biogenesis, is a chaperone for pre-18S rRNA folding. To test this, we used in vivo chemical probing with dimethyl sulfate to detect changes in pre-rRNA structure upon genetic manipulation of the yeast, Saccharomyces cerevisiae. Based on changes in nucleotide reactivity, we found that the U3 snoRNA is indeed required for folding of the pre-18S rRNA. Furthermore, we detected a new essential base pairing interaction that is likely the initial anchor that recruits the U3 snoRNA to the pre-rRNA, is a prerequisite for the subsequent interactions, and is required for the small subunit processome formation. Substitution of the 5′-ETS nucleotides of the pre-rRNA involved in this initial base pairing interaction is lethal, but growth is restored when a complementary U3 snoRNA is expressed. The U3 snoRNP, via base pairing, and its associated proteins, are part of the required machinery that orchestrates the folding of pre-rRNA that results in the assembly of the small ribosomal subunit

    Combined experimental and computational approach to identify non-protein-coding RNAs in the deep-branching eukaryote Giardia intestinalis

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    Non-protein-coding RNAs represent a large proportion of transcribed sequences in eukaryotes. These RNAs often function in large RNA–protein complexes, which are catalysts in various RNA-processing pathways. As RNA processing has become an increasingly important area of research, numerous non-messenger RNAs have been uncovered in all the model eukaryotic organisms. However, knowledge on RNA processing in deep-branching eukaryotes is still limited. This study focuses on the identification of non-protein-coding RNAs from the diplomonad parasite Giardia intestinalis, showing that a combined experimental and computational search strategy is a fast method of screening reduced or compact genomes. The analysis of our Giardia cDNA library has uncovered 31 novel candidates, including C/D-box and H/ACA box snoRNAs, as well as an unusual transcript of RNase P, and double-stranded RNAs. Subsequent computational analysis has revealed additional putative C/D-box snoRNAs. Our results will lead towards a future understanding of RNA metabolism in the deep-branching eukaryote Giardia, as more ncRNAs are characterized
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