Yangi tahrirdagi konstitutsiyaning fuqorolarimiz hayotida tutgan o’rni (Konstitutsiya meniki, seniki, bizniki, konstitutsiya - barchamizniki)

Ushbu maqolada joriy yilning 30-aprel sanasida referendum orqali amaliyotga joriy etilishi kutilayotgan yangi konstitutsiya, konstitutsiyaga kiritilayotgan oʻzgartishlarning xalqimiz hayotidagi oʻrni, eski konstitutsiya va tahliliy konstitutsiya oʻrtasidagi asosiy farqlar, yangi konstitutsiyaning fuqorolarimiz hayotidagi ahamiyati haqida toʻxtalib oʻtamiz

HYDRODYNAMIC CALCULATION OF JOINT WORK AND BARREL GAS WELLS BOTTOMHOLE FORMATION ZONE IN THE PRESENCE OF A LIQUID PHASE

Gas industry of Uzbekistan is planned to increase gas production to 60 billion. m3. To perform this task, along with the development of major new fields of research are related to the ability to maximize the performance of each individual well, which would reduce the cost of production of gas. A necessary condition for the increase of gas production from the well is to obtain reliable information about the possibilities of gas recovery beds.Gas industry of Uzbekistan is planned to increase gas production to 60 billion. m3. To perform this task, along with the development of major new fields of research are related to the ability to maximize the performance of each individual well, which would reduce the cost of production of gas. A necessary condition for the increase of gas production from the well is to obtain reliable information about the possibilities of gas recovery beds

MORPHOFUNCTIONAL CHARACTERISTICS OF CELLULAR ELEMENTS OF RAT TESTES UNDER THE INFLUENCE OF INSECTICIDE ROVIKURT

The purpose of the study was to study the characteristics of the response of germ and somatic cells to the action of rovicurt, as well as to study some aspects of the mechanism of this action. The research materials were the new insecticide Rovicurt, produced by the company “Hinoin” (Hungary) in the form of a 20% emulsion solution, proposed as a systemic acaricide. It mixes well with most organic solvents and consists of 23% Ambush (permethrin) and 2% tetramethrin (C21H20Cl2O3+C17H25O4). The experiment used white male and female rats weighing 150-200 g. To study this process, male rats (132 pcs.) were taken, subjected to a single action of rovicurt in doses of 380, 150, 75 mg/kg, as well as control animals. The studies were carried out on days 1, 3, 7, 14, 21 and 70 after exposure. And with repeated administration - doses of 38, 19 mg/kg for 2.5 months, as well as control animals. Research methods. Samples of testicular tissue were fixed in Carnoy's fluid and 2.5% glutaraldehyde solution, followed by additional fixation with 1% osmium tetroxide solution, dehydrated in alcohols of increasing strength, embedded in paraffin and in a mixture of epons. Paraffin sections were stained with hematoxylin-eosin, semi-thin sections prepared on an LKB-4800 ultratome were stained with methylene blue. Results. When exposed to rovicurt at a dose of 380 mg/kg, the proliferation of testicular stem cells (spermatogonia) is disrupted. This process is based on degenerative changes. Different populations of germ cells react differently to a single action of rovicurt (at doses of 75 and 159 mg/kg): differentiation of early and middle spermatids is suppressed, while late spermatids are activated. When exposed to pesticides in doses of 75, 150 and 380 mg/kg, damage to the genome of spermatogenic epithelial cells is observed. Conclusion. With acute and chronic action of pyrethroids, a change in the fine structure of the synaptonemal complex occurs, a delay in the differentiation of spermatocytes and spermatids, the appearance of multinucleated cells, as well as structural changes in sustentocytes and specialized connections between neighboring sustentocytes and germ cells

Yangi tahrirdagi konstitutsiyaning fuqorolarimiz hayotida tutgan o’rni (Konstitutsiya meniki, seniki, bizniki, konstitutsiya - barchamizniki)

Ushbu maqolada joriy yilning 30-aprel sanasida referendum orqali amaliyotga joriy etilishi kutilayotgan yangi konstitutsiya, konstitutsiyaga kiritilayotgan oʻzgartishlarning xalqimiz hayotidagi oʻrni, eski konstitutsiya va tahliliy konstitutsiya oʻrtasidagi asosiy farqlar, yangi konstitutsiyaning fuqorolarimiz hayotidagi ahamiyati haqida toʻxtalib oʻtamiz

Glasses and glass-ceramics of the system CaO-MgO-Al2O3-SiO2 obtained from natural sedimentary raw materials

Common and low-cost natural sedimentary raw materials such as ball clay, dolomite, quartz sand and diatomite were used as the main constituents for the production of glasses and glass-ceramics of the system CaO-MgO-Al2O3-SiO2. The crystallization of the glassy batch was promoted by the addition of a nucleation agent (TiO2). The crystallization sequence was examined by DTA, XRD, SEM, and thermal expansion analyses. Wollastonite and diopside are the main phases detected and the amount and grain size/shape of crystals were found to be strongly dependent on titania additions and on the annealing conditions. The characterization of relevant functional parameters of glass and glass-ceramic samples revealed interesting results

Glasses and glass-ceramics in the CaO–MgO–SiO2 system: diopside containing compositions - a brief review

Among different silicate systems, CaO−MgO−SiO2 is the one of the most promising due to abundance of reagents, easier fabrication, improved performance, and wide range of application. Analysis of the current literature sources denotes that phase diagram of CaO−MgO−SiO2 system is regularly used by researchers worldwide as constitutive model for synthesis glass-ceramic materials (GCs) possessing an adequate combination of high chemical durability, mechanical and electrical properties. In recent years, materials from this system attracted extra interest for applications in bone tissue repair owing to their ability to induce hydroxyapatite formation in contact with body fluids and to be resorbed in controllable degradation rate. In this brief review diopside containing compositions are specifically discussed. The main goal is to provide critical analysis of the experimental trials directed on synthesis of GC materials in the CaO−MgO−SiO2 system. Glass compositions were analysed through the standpoint of their location in the relevant region, or phase field, within a phase diagram to guide GC production and to make educated choices of compositions and processing parameters. Apart from Introduction and Conclusions this review comprises five consecutive parts. In the first part, constitution of phase diagram of CaO−MgO−SiO2 system is comprehensively discussed with connection to melts’ crystallization path and crystalline phase formation. In the second part, special attentiveness is drawn towards diopside- containing GCs produced from wastes and non-expensive natural raw materials. In this regard and taking into consideration presence of Al2O3 in the majority types of wastes, cross sections of CaO−MgO−SiO2−Al2O3 system with 10, 15 and 20% of Al2O3 are suggested to utilize when anticipating ultimate crystalline phase(s) formation. The following parts of this review are mostly addressed to recent advancement in producing optimized diopside-containing glass–ceramic biomaterials for bone repair as well as innovative sealants for solid oxide fuel cells (SOFC). Likewise, some other active areas of research and application for diopside containing GC compositions are briefly discussed.publishe

Dolomite-foamed bioactive silicate scaffolds for bone tissue repair

The use of three-dimensional (3D) scaffolds is recognized worldwide as a valuable biomedical approach for promoting tissue regeneration in critical-size bone defects. Over the last 50 years, bioactive glasses have been intensively investigated in a wide range of different clinical applications, from orthopedics to soft tissue healing. Bioactive glasses exhibit the unique capability to chemically bond to the host tissue and, furthermore, their processing versatility makes them very appealing due to the availability of different manufacturing techniques for the production of porous and interconnected synthetic bone grafts able to support new tissue growth over the whole duration of the treatment. As a novel contribution to the broad field of scaffold manufacturing, we report here an effective and relatively easy method to produce silicate glass-derived scaffolds by using, for the first time in the biomedical field, dolomite powder as a foaming agent for the formation of 3D bone-like porous structures. Morphological/structural features, crystallization behavior, and in vitro bioactivity in a simulated body fluid (SBF) were investigated. All the tested scaffolds were found to fulfil the minimum requirements that a scaffold for osseous repair should exhibit, including porosity (65-83 vol. %) and compressive strength (1.3-3.9 MPa) comparable to those of cancellous bone, as well as hydroxyapatite-forming ability (bioactivity). This study proves the suitability of a dolomite-foaming method for the production of potentially suitable bone grafts based on bioactive glass systems

Biological evaluation of a new sodium-potassium silico-phosphate glass for bone regeneration: In vitro and in vivo studies

In vitro and in vivo studies are fundamental steps in the characterization of new im-plantable materials to preliminarily assess their biological response. The present study reports the in vitro and in vivo characterizations of a novel experimental silicate bioactive glass (BG) (47.5 B, 47.5 SiO2-10 Na2O-10 K2O-10 MgO-20 CaO-2.5 P2O5 mol.%). Cytocompatibility tests were perfor-med using human mature osteoblasts (U2OS), human mesenchymal stem cells (hMSCs) and human endothelial cells (EA.hy926). The release of the early osteogenic alkaline phosphatase (ALP) marker suggested strong pro-osteogenic properties, as the amount was comparable between hMSCs cultivated onto BG surface and cells cultivated onto polystyrene control. Similarly, real-time PCR revealed that the osteogenic collagen I gene was overexpressed in cells cultivated onto BG surface without biochemical induction. Acute toxicity tests for the determination of the median lethal dose (LD50 ) al-lowed classifying the analyzed material as a slightly toxic substance with LD50 = 4522 ± 248 mg/kg. A statistically significant difference in bone formation was observed in vivo through comparing the control (untreated) group and the experimental one, proving a clear osteogenic effect induced by the implantation at the defect site. Complete resorption of 47.5 B powder was observed after only 3 months in favor of newly formed tissue, thus confirming the high osteostimulatory potential of 47.5 B glass

In Vivo Evaluation of 3D-Printed Silica-Based Bioactive Glass Scaffolds for Bone Regeneration

Bioactive glasses are often designed as porous implantable templates in which newly-formed bone can grow in three dimensions (3D). This research work aims to investigate the bone regenerative capability of silicate bioactive glass scaffolds produced by robocasting in comparison with powder and granule-like materials (oxide system: 47.5SiO2-10Na2O-10K2O-10MgO-20CaO-2.5P2O5, mol.%). Morphological and compositional analyses performed by scanning electron microscopy (SEM), combined with energy dispersive spectroscopy (EDS) after the bioactivity studies in a simulated body fluid (SBF) confirmed the apatite-forming ability of the scaffolds, which is key to allowing bone-bonding in vivo. The scaffolds exhibited a clear osteogenic effect upon implantation in rabbit femur and underwent gradual resorption followed by ossification. Full resorption in favor of new bone growth was achieved within 6 months. Osseous defect healing was accompanied by the formation of mature bone with abundant osteocytes and bone marrow cells. These in vivo results support the scaffold’s suitability for application in bone tissue engineering and show promise for potential translation to clinical assessment