50 research outputs found

    ACCOUNTING OF DAMPING IN THE EVALUATION AND SEISMIC STABILITY TASKS OF BUILDINGS AND STRUCTURES

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    It is proved that for the majority of building structures characterized by different damping elements. The goal of constructing matrix hysteretic damping that takes into account the internal friction in the material. The study is based on generalized hypothesis of E. S. Sorokin on the proportionality of the matrices of damping and stiffness elements of the structure. The methods of accounting for damping in the evaluation of the earthquake resistance of structures. The exact and approximate methods of decomposition of the motion equations for the mode shapes are considered. It is established that the empirical criterion of the approximate method applicability of accounting for damping and its refinement on the basis of the initial approximation can serve as the correlation coefficients of waveforms. It is shown that for non-proportional damping it is possible to approximate the decomposition of movements according to oscillations forms of non-damped system, if the forms are weakly correlated

    Multifrequency EPR spectroscopy of Ho3+ ions in synthetic forsterite

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    Electron paramagnetic resonance (EPR) of Ho3+ single ions and Ho3+-Mg2+-vacancy-Ho3+ associates in holmium-doped forsterite single crystals are studied at 9.4, 37.3 and 65-250 GHz. Crystals were grown from melt by the Czochralski technique in slightly oxidizing atmosphere. For both centers, directions of the principal magnetic axes and parameters of the effective spin Hamiltonians describing dependences of electron-nuclear levels on applied magnetic field are obtained. For Ho 3+ substituting Mg2+ in the M2 site as the single ion and for Ho3+ ions in dimer centers, values of crystal field parameters related to a real crystal lattice structure are estimated in the framework of the exchange charge model. The calculated crystal field energies, values of the g-factors of the ground Ho3+ quasi-doublet and the directions of the corresponding magnetic moments agree satisfactorily with the data obtained from measurements of EPR and optical absorption and site-selective luminescence spectra. © Springer-Verlag 2005

    Анализ многолетнего опыта изучения инактивированных культуральных вакцин для профилактики f клещевого энцефалита отечественного и зарубежного производства по показателю качества -специфическая активность (иммуногенность)

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    The analysis of the use of the method for the evaluation of specific (immunogenic) activity of vaccines for preventing tick-borne encephalitis (TBE vaccines) against protective dilution (PD50) and the minimum immunizing dose (MID50) has been performed. The method was standardized and submitted to the regulatory documents for TBE vaccines authorized in the Russian Federation. When analyzing the results of the study of specific (immunogenic) activity of TBE vaccines (107 TBE vaccine batches by different manufacturers have been studied) it was confirmed that the choice of real lethal dose (RLD50) indicator of TBE virus (test strain «Absettarov») in the range of 100-3000 LD50, the reasonability of using BALB /c cell-line mice, the effectiveness of the national method of determining immunogenicity in terms of MlD50 for TBE vaccines authorized in the Russian Federation. The reasonability of using immunogenicity reference standard for TBE-OSO 42-28-48 to assess the reproducibility of the experiments, and the homogeneity of laboratory animals in terms of quality. Methods for determining TBE vaccine immunogenicity («specific activity (immunogenicity)» in terms of PD50 and MID50 is applicable both for Russian commercial TBE vaccines and for FSME-Immun vaccine, manufactured by «Baxter Vaccine AG», Austria.Проведен анализ применения метода оценки специфической (иммуногенной) активности современных вакцин клещевого энцефалита (вакцины КЭ) по протективному разведению (ПР50) и минимальной иммунизирующей дозе (МИД50). Метод стандартизован и внесен в нормативные документы на зарегистрированные в Российской Федерации вакцины КЭ. При анализе результатов изучения специфической (иммуногенной) активности вакцин КЭ (исследовано 107 серий вакцин КЭ различных производителей) подтверждены: выбор показателя реальной летальной дозы (РЛД50) вируса КЭ (тест-штамм «Абсеттаров») в пределах 100-3000 ЛД50, целесообразность применения линейных мышей BALB/с, эффективность применения отечественного метода определения иммуногенности по показателю МИД50 для вакцин КЭ, зарегистрированных в Российской Федерации. Подтверждена целесообразность применения стандартного образца иммуногенности вакцины КЭ - ОСО 42-28-48 для оценки сходимости результатов постановки экспериментов и однородности лабораторных животных по качеству. Метод определения иммуногенности вакцин КЭ (показатель качества «Специфическая активность (иммуногенность)» по показателям ПР50 и МИД50 применим как для российских коммерческих вакцин КЭ, так и для вакцины ФСМЕ-Иммун, производства компании «Бакстер вакцины АГ», Австрия

    Перспективы применения NGAL и KIM-1 для диагностики острого почечного повреждения у пациентов, получающих антибактериальную терапию

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    The developers of Clinical Practice Guidelines for Acute Kidney Injury titled The Initiative to Improve Global Kidney Disease Outcomes (KDIGO) point at the need of new biomarkers for diagnosis acute kidney injury (AKI).The objective: to study and evaluate the diagnostic significance of the levels of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in patients with AKI in the early postoperative period when antibiotic therapy is used.Subjects and Methods. AKI frequency was assessed in 276 patients during the early postoperative period after the antibacterial drugs had been prescribed. Serum levels of KIM-1 and NGAL, glomerular filtration rate (GFR), creatinine, protein in urine were tested before the start of antibiotic therapy, in 24–48 hours, and in patients with AKI – additionally in 72–96 hours. The normal initial renal excretory function was registered only in 36 patients (13.04%). The majority of patients (242 patients, 86.96%) were diagnosed with chronic kidney disease of various stages.Results. NGAL and KIM-1 levels were higher in the group of patients with AKI before start of antibiotic therapy versus the group of patients with preserved renal function. However, a statistically significant increase in the level of KIM-1 and NGAL was found only in the group of patients with stages 3A and 3B of CKD versus the groups of patients with stages 1 and 2 of CKD. The second important observation is that a comorbid pathology in patients led to a high AKI incidence when antibiotic therapy was used – 35.86% (30–42%; 95%CI).Conclusion. The relationship of NGAL and KIM-1 levels with glomerular filtration rate (GFR) and KIM-1 level with the presence of proteinuria as indicators of impaired renal filtration function suggests that NGAL and KIM-1 levels reflect the state of renal filtration function. Based on this observation, it should be accepted that NGAL and KIM-1 levels can be used as markers for the diagnosis of AKI in patients receiving antibiotic therapy. The prescription of antibiotic therapy in the postoperative period in patients with surgical pathology and renal dysfunction leads to a high AKI incidence. Elevated KIM-1 and NGAL levels in AKI during the antibiotic therapy suggests their involvement in the reparation process.  Разработчики клинических практических рекомендаций по острому почечному повреждению «Инициативы по улучшению глобальных исходов заболеваний почек» (KDIGO) указывают на необходимость введения новых биомаркеров для диагностики острого повреждения почек (ОПП).Цель: изучение и оценка диагностической значимости уровней липокалина, ассоциированного с нейтрофильной желатиназой (NGAL), и молекулы повреждения почек-1 (KIM-1) у пациентов с ОПП в раннем послеоперационном периоде на фоне антибиотикотерапии.Материал и методы. У 276 пациентов проведена оценка частоты ОПП в раннем послеоперационном периоде после назначения антибактериальных препаратов. Исследование сывороточных уровней KIM-1 и NGAL, скорости клубочковой фильтрации (СКФ), креатинина, белка в моче проводили перед началом антибиотикотерапии, через 24‒48 ч, у пациентов с ОПП – дополнительно еще через 72‒96 ч. Нормальная изначальная экскреторная функция почек была зарегистрирована лишь у 36 (13,04%) больных. У большинства пациентов (242 пациента, 86,96%) диагностирована хроническая болезнь почек (ХБП) различных стадий.Результаты. Уровни NGAL и KIM-1 в группе пациентов с ОПП до начала антибиотикотерапии были выше, чем в группе с сохранной функцией почек. Однако статистически значимое повышение уровня KIM-1 и NGAL выявлено лишь в группе пациентов с 3A, 3B стадиями ХБП по сравнению с группами пациентов с 1-й и 2-й стадиями ХБП. Второе важное наблюдение состоит в том, что наличие у больных коморбидной патологии привело к высокой частоте развития ОПП при назначении антибиотикотерапии – 35,86% (30‒42%; 95%ДИ).Заключение. Взаимосвязь уровней NGAL и KIM-1 с уровнем клубочковой фильтрации (СКФ), а уровня KIM-1 – c наличием протеинурии как показателей нарушения фильтрационной функции почек позволяет считать, что уровни NGAL и KIM-1 отражают состояние фильтрационной функции почек. Отталкиваясь от данного наблюдения, следует принять, что уровни NGAL и KIM-1 могут быть использованы в качестве маркеров диагностики ОПП у пациентов, получающих антибактериальную терапию. Назначение антибиотикотерапии в послеоперационном периоде у больных с хирургической патологией и нарушенной функцией почек приводит к высокой частоте развития ОПП. Повышение на фоне антибиотикотерапии уровней KIM-1 и NGAL при ОПП предполагает их участие в репаративном процессе

    Genotyping of Capreolus pygargus Fossil DNA from Denisova Cave Reveals Phylogenetic Relationships between Ancient and Modern Populations

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    BACKGROUND: The extant roe deer (Capreolus Gray, 1821) includes two species: the European roe deer (C. capreolus) and the Siberian roe deer (C. pygargus) that are distinguished by morphological and karyotypical differences. The Siberian roe deer occupies a vast area of Asia and is considerably less studied than the European roe deer. Modern systematics of the Siberian roe deer remain controversial with 4 morphological subspecies. Roe deer fossilized bones are quite abundant in Denisova cave (Altai Mountains, South Siberia), where dozens of both extant and extinct mammalian species from modern Holocene to Middle Pleistocene have been retrieved. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed a 629 bp fragment of the mitochondrial control region from ancient bones of 10 Holocene and four Pleistocene Siberian roe deer from Denisova cave as well as 37 modern specimen belonging to populations from Altai, Tian Shan (Kyrgyzstan), Yakutia, Novosibirsk region and the Russian Far East. Genealogical reconstructions indicated that most Holocene haplotypes were probably ancestral for modern roe deer populations of Western Siberia and Tian Shan. One of the Pleistocene haplotypes was possibly ancestral for modern Yakutian populations, and two extinct Pleistocene haplotypes were close to modern roe deer from Tian Shan and Yakutia. Most modern geographical populations (except for West Siberian Plains) are heterogeneous and there is some tentative evidence for structure. However, we did not find any distinct phylogenetic signal characterizing particular subspecies in either modern or ancient samples. CONCLUSION/SIGNIFICANCE: Analysis of mitochondrial DNA from both ancient and modern samples of Siberian roe deer shed new light on understanding the evolutionary history of roe deer. Our data indicate that during the last 50,000 years multiple replacements of populations of the Siberian roe deer took place in the Altai Mountains correlating with climatic changes. The Siberian roe deer represent a complex and heterogeneous species with high migration rates and without evident subspecies structure. Low genetic diversity of the West Siberian Plain population indicates a recent bottleneck or founder effect

    Characterisation of Australian MRSA Strains ST75- and ST883-MRSA-IV and Analysis of Their Accessory Gene Regulator Locus

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    Background: Community-acquired methicillin-resistant Staphylococcus aureus have become a major problem in Australia. These strains have now been isolated throughout Australia including remote Indigenous communities that have had minimal exposure to healthcare facilities. Some of these strains, belonging to sequence types ST75 and ST883, have previously been reported to harbour highly divergent alleles of the housekeeping genes used in multilocus sequence typing. Methodology/Principal Findings: ST75-MRSA-IV and ST883-MRSA-IV isolates were characterised in detail. Morphological features as well as 16S sequences were identical to other S. aureus strains. Although a partial rnpB gene sequence was not identical to previously known S. aureus sequences, it was found to be more closely related to S. aureus than to other staphylococci. Isolates also were screened using diagnostic DNA microarrays. These isolates yielded hybridisation results atypical for S. aureus. Primer directed amplification assays failed to detect species markers (femA, katA, sbi, spa). However, arbitrarily primed amplification indicated the presence of unknown alleles of these genes. Isolates could not be assigned to capsule types 1, 5 or 8. The allelic group of the accessory gene regulator (agr) locus was not determinable. Sequencing of a region of agrB, agrC and agrD (approximately 2,100 bp) revealed a divergent sequence. However, this sequence is more related to S. aureus agr alleles I and IV than to agr sequences from other Staphylococcus species. The predicted autoinducing peptide (AIP) sequence of ST75 was identical to that of agr group I, while the predicted AIP sequence of ST883 was identical to agr group IV. Conclusions/Significance: The genetic properties of ST75/ST883-MRSA may be due to a series of evolutionary events in ancient insulated S. aureus strains including a convergent evolution leading to agr group I- or IV-like AIP sequences and a recent acquisition of SCCmec IV elements

    A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

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    In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements

    A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

    Get PDF
    In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements
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