25 research outputs found

    Properties of Calcium Phosphate/Hydrogel Bone Grafting Composite on the Model of Diaphyseal Rat Femur’s Defect: Experimental Study

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    Background. The problem of bone defects replacement is relevant nowadays, that is why many scientists create new synthetic bone substitutes, but the ideal material has not been found so far. The aims of the study: 1) to determine the suitability of the monocortical defect model in the rat femur diaphysis with additional prophylactic reinforcement with a bone plate for assessing the biological properties of implanted materials using the commercially available ChronOS material as an example; 2) to assess of the osteoconductive properties of composite materials based on poly(ethylene glycol)diacrylate and octacalcium phosphate with architecture Kelvin and gyroid types on the developed model. Methods. A prospective study, level of evidence II. A monocortical defect of the rat femoral diaphysis (length 7 mm) was produced under anaesthesia in aseptic conditions and fixed with a polyetheretherketone plate and six titanium screws. In the control group, the defect was left empty. In other groups, blocks of one of three materials were implanted сhronOS and composites of poly(ethylene glycol)diacrylate and octacalcium phosphate with 3D-printed Kelvin and gyroid architectures. After 3 and 6 weeks, the rats were sacrificed, and histological examination of the defect zone was performed. The amount of newly formed bone tissue was histometricly assessed, followed by statistical processing of the results. Results. All rats have reached the planned endpoint, and there were no infectious complications or loss of fixation. Histological examination of the defect zone revealed minimal bone growth in the Control group, rather slow bone formation in the Gyroid group, and statistically significantly more pronounced bone formation in the pores of the materials in the Kelvin and Chronos groups. Conclusions. Bone defect in this model was not spontaneously filled with bone tissue and allowed us to study the biological properties of bone substitutes (the ability to biodegrade and osteoconductive properties). The osteoconductive properties of a composite material based on poly(ethylene glycol)diacrylate and octacalcium phosphate with a Kelvin architecture are higher than with a gyroid architecture and are comparable to that of the сhronOS

    Phenological shifts of abiotic events, producers and consumers across a continent

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    Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

    Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

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    We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

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    Development of a power supply for multi-angle electric impedance tomography complex

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    In the present work, the development of a multi-channel power supply for the hardware part of the hardware-software complex of multiangle electric impedance tomography is considered. The requirements for the developed module are considered based on the selected hardware components, as well as the patient and medical personnel safety requirements, taking into account the standards developed by the International Electrotechnical Commission. Taking into account the formulated requirements, a structural, electrical schematic diagram of the power supply was developed, as well as a printed circuit board and an assembly drawing, and a prototype model was built. The issues of patient and medical personnel safety during the research using the multi-angle electric impedance tomography method with the use of the developed module are considered, including in the case of joint use with electrosurgical devices or defibrillators

    Nanoparticles of Cerium Dioxide – an Effective Antiviral Agent and Adjuvant of Biologically Active Molecules

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    There was studied the influence of cerium dioxide nanoparticles on the cytokines production in the conditions of their application in the composition with interferon and as an independent drug. Applying the CDN in combination with IFN showed an increased interferon response of experimental mice compared with unmodified IFN. IFN-CDN nanobiocomplex does not increase the level of TNF production, which indirectly indicates the safety of the applying of such complex. There was studied the effect of CDN as a therapeutic agent on the cytokines production in the treatment of modeled herpes simplex virus-1 infection. It was found that CDN is able to increase IFN and TNF levels and prolong their effects. It was found that NDC is able to increase the level of IFN and FNP and prolong their effects. The application of CDN caused increasing of TNF levels and their prolonging action. There was shown the significant increasing (to three weeks) in IFN titers on the step of decreasing in TNF titers in the group, that was infected and then treated with NCD. In the non-treated group and in the aciclovir-treated animal group, IFN titers were significantly lower.The obtained results testify to the effectiveness of NDC as a modifying agent for interferon and as a promising agent for the treatment of systemic herpetic infectio
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