196 research outputs found

    A flat compound piezoelectric actuator of a type “a shaking beam”

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    It is investigated piezoelectric actuator, consisting of two flat converters of longitudinal fluctuations which ends are close by the hence – « a shaking beam ». Also is resulted the principle of work actuator in quality stator of the motor, and also as the ultrasonic concentrator of fluctuations. Additionally is made research of it actuator with the help of programs computer modeling. And is carried out optimization of the sizes driver hence actuator. Theoretical researches are confirmed experimentally, with the help of the precision laser equipmen

    Multiscale Biomechanics and Tribology of Inorganic and Organic Systems

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    This open access book gathers authoritative contributions concerning multiscale problems in biomechanics, geomechanics, materials science and tribology. It is written in memory of Sergey Grigorievich Psakhie to feature various aspects of his multifaceted research interests, ranging from theoretical physics, computer modeling of materials and material characterization at the atomic scale, to applications in space industry, medicine and geotectonics, and including organizational, psychological and philosophical aspects of scientific research and teaching as well. This book covers new advances relating to orthopedic implants, concerning the physiological, tribological and materials aspects of their behavior; medical and geological applications of permeable fluid-saturated materials; earthquake dynamics together with aspects relating to their managed and gentle release; lubrication, wear and material transfer in natural and artificial joints; material research in manufacturing processes; hard-soft matter interaction, including adhesive and capillary effects; using nanostructures for influencing living cells and for cancer treatment; manufacturing of surfaces with desired properties; self-organization of hierarchical structures during plastic deformation and thermal treatment; mechanics of composites and coatings; and many more. Covering established knowledge as well as new models and methods, this book provides readers with a comprehensive overview of the field, yet also with extensive details on each single topic

    Reactivity of an organism at hypertrophic skin scars

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    The aim of the research was to assess the reactivity of female organism with hypertrophic scars. 42 women of 16-35years were examined on the 5-7th day of the menstrual cycle, 17 of them had normotrophic and 25 - hypertrophic scars. The quality of scars (according to the clinical and morphological characteristics), white blood cells, blood lipids, hormonal and immune status were assessed. Non-parametric Mann - Whitney U-test and discriminant analysis were used at statistical processing of the results. Average values and standard deviations were also calculated for interpreting the results of quantitative indications. As the result of discriminant analysis the most informative indicators of reactivity of an organism that allow to differentiate patients of the studied groups were defined for patients with normotrophic and hypertrophic scars. It was concluded that the imbalance of steroid hormones (progesterone, cortisol, testosterone, estrogen) was important in the etiopathogenesis of hypertrophic scars

    Correctability of thyroid dysfunction by interm ittent hypobaric hypoxia

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    The work is devoted to studying the effect of intermittent hypobaric hypoxia on thyroid dysfunction. Simulation of thyroid dysfunction by oral introduction of levothyroxine sodium in a dose of 50 mg/kg body weight of the animal is accompanied by an increase in the concentration thyroid hormones and decreased levels of TSH in the blood, decrease blood supply to the thyroid gland and the structural changes, characteristic of reducing its functional activity. The use of intermittent hypobaric hypoxia reduces recovery time of hormonal imbalance in the pituitary gland-thyroid gland, structural, functional and microvascular disturbances in the thyroid gland.Работа посвящена изучению влияния прерывистой гипобарической гипоксии натиреоидную дисфункцию. Моделирование тиреоидной дисфункции путем перорального введения левотироксина натрия в дозе 50 мкг/кг массы тела животного сопровождается увеличением концентрации тиреоидных гормонов и снижением уровня ТТГ в крови, уменьшением кровоснабжения щитовидной железы и структурными изменениями, характерными для понижения её функциональной активности. Применение прерывистой гипобарической гипоксии сокращает сроки восстановления гормонального дисбаланса в системе гипофиз-щитовидная железа, структурно-функциональных и микрососудистых наррений в щитовидной железе

    The possibility to decrease biological activity of chrysotile-asbestos

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    The paper presents a study of natural chrysotile and 15 samples modified using different temperature and pressure. The morphology, dimensions, chemical composition, crystalline structure, and technologic characteristics of the samples studied were similar. The numbers of negatively charged centers on the surface of fibers were about the same in all the samples. In two modified asbestos samples the number of positively charged centers was less than in the native one. In these samples the energy of interaction of charged centers with macromolecules of rodamin and eozin was also less than in the sample of natural chrysotile. It directly correlated with cytotoxicity and mutagenicity of them. The principal possibility to decrease the biological activity of asbestos has been discussed

    Mitochondria of the Yeasts Saccharomyces cerevisiae and Kluyveromyces lactis Contain Nuclear rDNA-Encoded Proteins

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    In eukaryotes, the nuclear ribosomal DNA (rDNA) is the source of the structural 18S, 5.8S and 25S rRNAs. In hemiascomycetous yeasts, the 25S rDNA sequence was described to lodge an antisense open reading frame (ORF) named TAR1 for Transcript Antisense to Ribosomal RNA. Here, we present the first immuno-detection and sub-cellular localization of the authentic product of this atypical yeast gene. Using specific antibodies against the predicted amino-acid sequence of the Saccharomyces cerevisiae TAR1 product, we detected the endogenous Tar1p polypeptides in S. cerevisiae (Sc) and Kluyveromyces lactis (Kl) species and found that both proteins localize to mitochondria. Protease and carbonate treatments of purified mitochondria further revealed that endogenous Sc Tar1p protein sub-localizes in the inner membrane in a Nin-Cout topology. Plasmid-versions of 5′ end or 3′ end truncated TAR1 ORF were used to demonstrate that neither the N-terminus nor the C-terminus of Sc Tar1p were required for its localization. Also, Tar1p is a presequence-less protein. Endogenous Sc Tar1p was found to be a low abundant protein, which is expressed in fermentable and non-fermentable growth conditions. Endogenous Sc TAR1 transcripts were also found low abundant and consistently 5′ flanking regions of TAR1 ORF exhibit modest promoter activity when assayed in a luciferase-reporter system. Using rapid amplification of cDNA ends (RACE) PCR, we also determined that endogenous Sc TAR1 transcripts possess heterogeneous 5′ and 3′ ends probably reflecting the complex expression of a gene embedded in actively transcribed rDNA sequence. Altogether, our results definitively ascertain that the antisense yeast gene TAR1 constitutes a functional transcription unit within the nuclear rDNA repeats

    Spliceosome-mediated decay (SMD) regulates expression of nonintronic genes in budding yeast

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    We uncovered a novel role for the spliceosome in regulating mRNA expression levels that involves splicing coupled to RNA decay, which we refer to as spliceosome-mediated decay (SMD). Our transcriptome-wide studies identified numerous transcripts that are not known to have introns but are spliced by the spliceosome at canonical splice sites in Saccharomyces cerevisiae. Products of SMD are primarily degraded by the nuclear RNA surveillance machinery. We demonstrate that SMD can significantly down-regulate mRNA levels; splicing at canonical splice sites in the bromodomain factor 2 (BDF2) transcript reduced transcript levels roughly threefold by generating unstable products that are rapidly degraded by the nuclear surveillance machinery. Regulation of BDF2 mRNA levels by SMD requires Bdf1, a functionally redundant Bdf2 paralog that plays a role in recruiting the spliceosome to the BDF2 mRNA. Interestingly, mutating BDF2 5' splice site and branch point consensus sequences partially suppresses the bdf1Δ temperature-sensitive phenotype, suggesting that maintaining proper levels of Bdf2 via SMD is biologically important. We propose that the spliceosome can also repress protein-coding gene expression by promoting nuclear turnover of spliced RNA products and provide an insight for coordinated regulation of Bdf1 and Bdf2 levels in the cell

    Dynamic Acetabular Cup Orientation during Gait: A Study of Fast- and Slow-Walking Total Hip Replacement Patients

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    The dynamic orientation of total hip replacement acetabular cups during walking may vary substantially from their assumed position at surgical implantation and may vary between individuals. The scale of this effect is of interest for both pre-clinical device testing and for pre-operative surgical planning. This work aimed to evaluate (1) patient variation in dynamic cup orientation; (2) whether walking speed was a candidate proxy measure for the dynamic cup orientation; and (3) the relationships between dynamic cup orientation angles and planar pelvic angles. Pelvic movement data for patients with fast (20 patients) and slow (19 patients) self-selected walking speeds were used to calculate acetabular cup inclination and version angles through gait. For aim 1, the range and extremes of acetabular cup orientation angles were analysed for all patients. A large patient-to-patient variation was found in the ranges of both inclination angle (1° to 11°) and version angle (4° to 18°). The version angle was typically retroverted in comparison to the implantation position (greatest deviation 27°). This orientation is substantially different to the static, 0° version, simplifying assumptions in pre-clinical ‘edge loading’ testing. For aim 2, the cup orientation angles were compared between the fast- and slow-walking groups using statistical parametric mapping. The only significant differences observed were for cup version angle, during ~12% of the gait cycle before toe-off (p < 0.05). Therefore, self-selected walking speed, in isolation, is not a sufficient proxy measure for dynamic acetabular orientation. For aim 3, correlations were recorded between the acetabular cup orientation angles and the planar pelvic angles. The cup inclination angle during gait was strongly correlated (Spearman’s coefficient −1) with pelvic obliquity alone, indicating that simple planar assessment could be used to anticipate inclination angle range. The cup version angle was correlated with both pelvic rotation and tilt (Spearman’s coefficient 0.8–1), indicating that cup version cannot be predicted directly from any single pelvic movement. This complexity, along with the interaction between inclination angle and range of version angle, supports the use of computational tools to aid clinical understanding
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