345 research outputs found

    Flexural properties of the epoxy resin filled with single and hybrid carbon nanofillers

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    The aim of this paper was to estimate the effect of moisture and temperature on the flexural properties of the epoxy filled with single and hybrid carbon nanofillers (CNTs and CNFs) and to reveal the most environmentally stable NC. Water absorption at 70 °C until equilibrium moisture content and heating at 70 °C for 4 weeks were followed by freezing at - 20 °C for 8 weeks. Microstructural characterization of optical images revealed homogeneous dispersion of all carbon nanofillers in the epoxy resin at microscale. Positive nanofiller effects were found for sorption, flexural and thermophysical characteristics of the epoxy resin. The most environmentally stable NC was epoxy filled with 0.1 wt. % of CNTs/CNFs hybrid, which had the lowest effect of temperature and moisture on mechanical characteristics, along with the lowest equilibrium water content and diffusivity

    Microparticles prepared from biodegradable polyhydroxyalkanoates as matrix for encapsulation of cytostatic drug

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    Microparticles made from degradable polyhydroxyalkanoates of different chemical compositions a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids (P3HB/4HB), 3-hydroxybutyric and 3-hydroxyvaleric acids (P3HB/3HV), 3-hydroxybutyric and 3-hydroxyhexanoic acids (P3HB/3HHx) were prepared using the solvent evaporation technique, from double emulsions. The study addresses the influence of the chemical compositions on the size and ξ-potential of microparticles. P3HB microparticles loaded with doxorubicin have been prepared and investigated. Their average diameter and ξ-potential have been found to be dependent upon the level of loading (1, 5, and 10 % of the polymer mass). Investigation of the in vitro drug release behavior showed that the total drug released from the microparticle into the medium increased with mass concentration of the drug. In this study mouse fibroblast NIH 3T3 cells were cultivated on PHA microparticles, and results of using fluorescent DAPI DNA stain, and MTT assay showed that microparticles prepared from PHAs of different chemical compositions did not exhibit cytotoxicity to cells cultured on them and proved to be highly biocompatible. Cell attachment and proliferation on PHA microparticles were similar to those on polystyrene. The cytostatic drug encapsulated in P3HB/3HV microparticles has been proven to be effective against HeLa tumor cells.Russia (Federation) (Agreement 11.G34.31.0013)Program of the President of Russia for Young Doctors of Sciences (Grant MD-3112.2012.4

    EXPRESSION OF рSTAT3 TRANSCRIPTION FACTOR IN PERIPHERAL BLOOD MONONUCLEAR CELLS AND ITS LEPTIN-INDUCED MODULATION IN BRONCHIAL ASTHMA

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    The aim of this study was to evaluate expression rates of phosphorylated STAT3 (рSTAT3) transcription factor in peripheral blood mononuclear cells (PBMC) and some features of its modulation by leptin in various clinical forma of bronchial asthma (BA). Materials and methods. We evaluated 25 healthy persons and 62 BA patients. pSTAT3 expression in PBMC was measured by means of flow cytometry.Results. A phenomenon of increased pSTAT3 expression was registered in PBMC from BA patients. A most sufficient elevation of pSTAT3 levels was revealed in allergic clinical variant of the disorder. Leptin was shown to increase pSTAT3 expression in PBMCs from healthy persons only. In allergic BA, such effect of leptin was not observed, whereas a trend for pSTAT increase was shown in non-allergic BA. In allergic BA, we have revealed a direct correlation between the STAT3-mediated leptin signaling index and bronchial patency parameters. Appropriate inverse correlation was registered in non-allergic BA.Conclusion. We have revealed some characteristics of рSTAT3 expression in PBMCs and its modulation by leptin in various clinical forms of BA, thus providing a potential basis for development of targeted therapy aimed for transduction of different cytokine signals mediated by STAT3 transcription factor

    Drought resistance of introgressive spring common wheat lines with genetic material of tall wheatgrass

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    Background. To breed drought-resistant cultivars of common wheat1 (Triticum aestivum L.), it is important to use the gene pools of its relatives, including tall wheatgrass Thinopyrum ponticum (Podpěra) Z.-W. Liu & R.- C. Wang (= Agropyron elongatum (Host) Beauv.).   Materials and methods. The introgressive lines of spring common wheat with T. ponticum genetic material and standard cultivars were studied in the field in the southern forest-steppe of Western Siberia using generally recognized methods. The ecological plasticity of cultivars and introgressive lines by grain yield and yield components was calculated according to the method of S. A. Eberhart and W. A. Russell. During the research period, there was a prolonged drought in 2012, and irregular short severe droughts occurred in 2013, 2014, and 2017.   Results. An analysis of the ecological plasticity of standard cultivars adapted to the regional conditions showed that cv. ‘Pamyati Azieva’ corresponded to the extensive type, and cvs. ‘Duet’, and ‘Erythrospermum 59’ corresponded to the intensive type. Under drought conditions, the grain yield of cv. ‘Pamyati Azieva’ was determined by the stable development of productive tiller number, seed number and grain yield per main ear, but plasticity in 1000 grain weight was observed. Cvs. ‘Duet’ and ‘Erythrospermum 59’ showed ecological plasticity due to the adaptive development of two or three yield components. Introgressive lines exceeded the standard cultivars in grain yield (1.1–2.2 times) in dry seasons. Five lines were similar to cv. ‘Pamyati Azieva’ in plasticity and stability, and under drought conditions they demonstrated high and stable development of three or four yield components. The intensive lines formed their yield due to the compensatory development of three yield components in different combinations.   Conclusion. Introgressive lines with T. ponticum genetic material are valuable for breeding spring common wheat cultivars with various drought-adaptation mechanisms

    The Cestode Community in Northern Fur Seals (\u3cem\u3eCallorhinus ursinus\u3c/em\u3e) on St. Paul Island, Alaska

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    The diversity and ecology of cestodes from the northern fur seals, Callorhinus ursinus (NFS), were examined using newly collected material from 756 humanely harvested subadult males between 2011 and 2014. NFSs were collected from five different haul-outs on St. Paul Island, Alaska. A total of 14,660 tapeworms were collected with a prevalence of 98.5% and intensity up to 107 cestodes per host (mean intensity 19.7 ± 16.5 SD). Three species of tapeworms were found: Adenocephalus pacificus (Diphyllobothriidea) was the most prevalent (prevalence 97.4%), followed by Diplogonoporus tetrapterus (49.7%), and 5 immature specimens of Anophryocephalus cf. ochotensis (Tetrabothriidea) (0.5%). Most of the cestodes found in the NFS were immature (69.7%). However, only 0.9% of cestodes were in larval (plerocercoid) stages. The species composition, prevalence and intensity of cestodes from these NFSs were not statistically different between the five separate haul-outs. Significant increases in the intensity of NFS infections were observed during the study period

    Superbase ionic liquids for effective cellulose processing from dissolution to carbonisation

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    This is the author accepted manuscript. The final version is available from Royal Society of Chemistry via the DOI in this recordA range of superbase derived ionic liquids (SILs) was synthesised and characterised. Their ability to dissolve cellulose and the characteristics of the produced fibres were correlated to their specific structural and solvent properties. 17 ionic liquids (ILs) (including 9 novel) were analysed and six ILs were selected to produce fibres: 1-ethyl-3-methylimidazolium acetate [C2C1im][OAc], 1-ethyl-3-methylimidazolium diethyl phosphate [C2C1im][DEP] and the SILs 1-ethyl-1,8-diazabicyclo[5.4.0]undec-7-enium diethylphosphate [DBUEt][DEP], 1,8-diazabicyclo[5.4.0]undec-7-enium acetate [DBUH][OAc], 1,5-diazabicyclo[4.3.0]non-5-enium acetate [DBNH][OAc] and 1-ethyl-1,5-diazabicyclo[4.3.0]non-5-enium diethylphsophate [DBNEt][DEP]. The mechanical properties of these fibres were investigated. The obtained fibres were then carbonised to explore possible application as carbon fibre precursors. The fibres obtained using a mixture of 1,5-diazabicyclo[4.3.0]non-5-enium based SILs with acetate and hexanoate anions (9 : 1), [DBNH][OAc][Hex], showed a promising combination of strength, stiffness and strain at failure values for applications in textiles and fibre reinforcement in renewable composites. Using Raman spectroscopy it is demonstrated that these fibres exhibit a relatively high degree of structural order, with fewer defects than the other materials. On the other hand, analogous fibres based on imidazolium cation with acetate and hexanoate anions (9 : 1), [C2C1im][OAc][Hex] showed a decline in the quality of the produced fibres compared to the fibres produced from [C2C1im][OAc], [C2C1im][DEP] or [DBNH][OAc][Hex].We would like to thank the EPSRC grant number EP/L017679/01 for financial support (AERO RB1717)

    Опыт консервативной реабилитации пациентов с ювенильным хроническим артритом

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    Objective: to estimate a need for conservative rehabilitation treatment in patients with juvenile chronic arthritis (JCA).Material and methods. Data on the principles and procedures of rehabilitation treatment were analyzed in patients with JCA on the basis of 25- year experience. The need for these packages of measures in 1999, 2008, and 2014 was compared. Standard procedures for joints at different sites were described. According to the degree of joint functions, there were rehabilitation treatment packages: corrective, mobilization, and general health-improving.Results and discussion. All patients with juvenile arthritis need rehabilitation (physical, psychological, and social). Comparison of the total number of patients who had received rehabilitation treatment in 1999, 2008, and 2014 showed a small trend towards its reduction. This is due to the smaller number of patients with dysfunctions and to the larger number of those without movement disorders who had received adequate treatment in early periods of the disease. The high percentage of patients having limited joint functions needs a mobilization package. Analysis of the data available in the literature and the authors' experience may lead to the conclusion that all patients with JCA need exercise therapy. The latter is a major procedure for physical rehabilitation and should be included in the standards for adjuvant treatment during basic medical therapy. Emphasis is laid on the importance of the early initiation of treatment to prevent incapacitating deformity at early stages of the disease.Цель исследования – оценить потребность в консервативном реабилитационном лечении у пациентов с ювенильным хроническим артритом (ЮХА).Пациенты и методы. На основании 25-летнего опыта работы проанализированы данные о принципах и методиках реабилитационного лечения больных ЮХА. Сопоставлена потребность в проведении данных комплексов в 1999, 2008 и 2014 гг. Описаны стандартные методики для суставов различной локализации. Представлены комплексы реабилитационного лечения в зависимости от степени выраженности функциональных нарушений суставов: корригирующий, мобилизационный и общеукрепляющий.Результаты и обсуждение. Все пациенты с ювенильным артритом нуждаются в реабилитации (физической, психологической, со- циальной). При сравнении общего числа больных, получивших реабилитационное лечение в 1999, 2008 и 2014 гг., отмечена небольшая тенденция к его снижению. Это объясняется уменьшением числа пациентов с функциональными нарушениями и увеличением числа пациентов без двигательных нарушений, получавших адекватное лечение в ранние сроки заболевания. Высокий процент пациентов, имеющих ограничение функции суставов, нуждается в проведении мобилизационного комплекса. Анализ данных литературы и собственного опыта позволяет сделать вывод о необходимости лечебной физкультуры (ЛФК) у всех больных ЮХА. ЛФК является основной методикой физической реабилитации и должна входить в стандарты дополнительного лечения на фоне основной медикаментозной терапии. Подчеркнута важность раннего начала лечения для предотвращения развития инвалидизирующей деформации в начальных стадиях заболевания

    The role of highly dispersed silica nanoparticles in the realization of the effects of granulosa on the maturation and fertilization competence of <i>Sus scrofa domesticus</i> oocytes

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    Reproductive technologies are some of the key directions in the context of the need to preserve and select highly productive farmed animals in terms of economically useful traits. Improvements of the existing models of the in vitro oocyte maturation system help to solve the problem of low yield of porcine embryos at the final stages of preimplantation development. In the present study, a model of culture medium for gametes (NCSU-23 with 10 % homologous follicular fluid, 10 IU hCG and 10 IU eCG) modernized by the addition of 1·106 granulosa cells (GCs) per ml and 0.001 % of highly dispersed silica nanoparticles (HDSn) is proposed for use in the IVM and IVF technology of donor porcine oocytes. Analysis of the oocyte chromatin status by the Tarkowsky method and assessment of the level of destructive changes in chromatin (apoptosis, pyknosis) revealed a significant percentage increase in matured oocytes and a decrease in the proportion of granulosa cells with degenerated chromatin when using the original culture system. The positive effects of a joint addition of GCs and HDSn to the maturation system have made it possible to increase the indicators of the meiotic maturation and fertilization of oocytes. Optimal results of developmental competence of oocytes were achieved with the joint use of GCs and HDSn in the maturation system (the proportion of matured cells reached 89 %, the level of oocytes with chromosome degeneration was 12 %, 39 % of embryos reached the final stage of preimplantation development). The positive effect of HDSn on oocyte fertilization was accompanied by an abrupt decrease in destructive processes in GCs during culture in the presence of HDSn. The level of somatic cells with pyknotic nuclei was 32 % and the level of apoptosis (TUNEL-test), 21 %, compared with the control (43 and 31 %, p &lt;0.01, respectively). Thus, a high efficiency of the porcine oocyte maturation system in the joint culture of gametes with GCs and HDSn was revealed. It makes it possible to recommend a model of this culture medium at the IVM of female gametes of Sus scrofa domesticus for improving the quality of donor oocytes used in cell and genetic engineering

    In Vivo Efficacy of a Cocktail of Human Monoclonal Antibodies (CL184) Against Diverse North American Bat Rabies Virus Variants

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    Following rabies virus (RABV) exposure, a combination of thorough wound washing, multiple-dose vaccine administration and the local infiltration of rabies immune globulin (RIG) are essential components of modern post-exposure prophylaxis (PEP). Although modern cell-culture-based rabies vaccines are increasingly used in many countries, RIG is much less available. The prohibitive cost of polyclonal serum RIG products has prompted a search for alternatives and design of anti-RABV monoclonal antibodies (MAbs) that can be manufactured on a large scale with a consistent potency and lower production costs. Robust in vitro neutralization activity has been demonstrated for the CL184 MAb cocktail, a 1:1 protein mixture of two human anti-RABV MAbs (CR57/CR4098), against a large panel of RABV isolates. In this study, we used a hamster model to evaluate the efficacy of experimental PEP against a lethal challenge. Various doses of CL184 and commercial rabies vaccine were assessed for the ability to protect against lethal infection with representatives of four distinct bat RABV lineages of public health relevance: silver-haired bat (Ln RABV); western canyon bat (Ph RABV); big brown bat (Ef-w1 RABV) and Mexican free-tailed bat RABV (Tb RABV). 42–100% of animals survived bat RABV infection when CL184 (in combination with the vaccine) was administered. A dose-response relationship was observed with decreasing doses of CL184 resulting in increasing mortality. Importantly, CL184 was highly effective in neutralizing and clearing Ph RABV in vivo, even though CR4098 does not neutralize this virus in vitro. By comparison, 19–95% survivorship was observed if human RIG (20 IU/kg) and vaccine were used following challenge with different bat viruses. Based on our results, CL184 represents an efficacious alternative for RIG. Both large-scale and lower cost production could ensure better availability and affordability of this critical life-saving biologic in rabies enzootic countries and as such, significantly contribute to the reduction of human rabies deaths globally
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