Composition of Initiated Cracking Products of High-sulfur Natural Bitumen

The analysis of the cracking products of bitumen Karmalskoye deposits (the content of fractions boiling up to 200 °C 6,7% wt.) has been performed. The influence of power plant coal ash microspheres on orientation of cracking bitumen components is stated. Bitumen cracking leads to significant yields of gas and coke for more than 20% wt. and destructions of all components. The initiated bitumen cracking in the presence of 10% microspheres at cracking temperature 450 °C leads to reduction of gas and coke yields and increase in fractions of ibp (initial boiling point) –360 °C at 10% wt. in comparison with products of the thermal bitumen cracking. The analysis of composition and amount of sulfur compounds in initial bitumen and the cracking products in the various conditions has shown that the thermal cracking leads to increased homologues benzothiophene contents due to partial destruction of resins, and to decrease in the content of homologues dibenzothiophene

Composition of Pre-ozonated High-Sulfur Natural Bitumen Cracking Products

The results analysis of fractional and material composition of the cracking products of Ashalchinskoye and Karmalskoye bitumen deposits was presented in this work. The effect of bitumen ozone-oxygen mixture pretreatment followed by cracking on thermolysis processes was investigated. It was shown that molecules of resins and asphaltenes containing large amounts of aliphatic fragments in its structure readily undergo thermal decomposition to form additional distillate fractions. Low content of aliphatic fragments leads to aromatization of the naphthenic cycles in the molecule of resins and asphaltenes, the thermal degradation reactions proceed in high yields of gas and coke

Fibrin Glue Implants Seeded with Dental Pulp and Periodontal Ligament Stem Cells for the Repair of Periodontal Bone Defects: A Preclinical Study

A technology to create a cell-seeded fibrin-based implant matching the size and shape of bone defect is required to create an anatomical implant. The aim of the study was to develop a technology of cell-seeded fibrin gel implant creation that has the same shape and size as the bone defect at the site of implantation. Using computed tomography (CT) images, molds representing bone defects were created by 3D printing. The form was filled with fibrin glue and human dental pulp stem cells (DPSC). The viability, set of surface markers and osteogenic differentiation of DPSC grown in fibrin gel along with the clot retraction time were evaluated. In mice, an alveolar bone defect was created. The defect was filled with fibrin gel seeded with mouse DPSC. After 28 days, the bone repair was analyzed with cone beam CT and by histological examination. The proliferation rate, set of surface antigens and osteogenic potential of cells grown inside the scaffold and in 2D conditions did not differ. In mice, both cell-free and mouse DPSC-seeded implants increased the bone tissue volume and vascularization. In mice with cell-seeded gel implants, the bone remodeling process was more prominent than in animals with a cell-free implant. The technology of 3D-printed forms for molding implants can be used to prepare implants using components that are not suitable for 3D printing