No abstract

A polymer polyethyleneimine (PEI) can be used in various cell technologies, including the nonviral transfection of animal and human eukaryotic cells. We used the polymer (in the 1 mg/ml concentration) to produce the ultrathin fi lms at the culture plastic that could enhance the adhesive properties of the human mesenchymal stromal cells (hMSCs) isolated from the heterogeneous cell population of the marrow. Our study demonstrated that the PEI fi lms prevent cell-to-cell cooperation and "glomeration" of hMSCs at the surface of a cultural plate, and enhance hMSCs viability and metabolic activity in vitro. The stimulating effects of PEI on cell proliferation are negligible. Moreover, the immobilization of the human platelet lysate (PL) in 5% or 10% concentrations into the PEI solution increases hMSCs viability and effectiveness of their culturing under the deprivation condition and in the serum-free medium. We suggest to use the PEI fi lms containing the immobilized growth factors in the regenerative medicine-at the stages of hMSCs isolation and growth of their biomass.

This study examines the adhesive properties and cytotoxicity of polyelectrolyte nanofilms from polyethyleneimine (PEI), polyallylamine hydrochloride (PAH) and sodium polystyrene sulfonate (PSS) on human bone marrow mesenchymal stromal cells (h-MSCs) and mouse adipose tissue (m-MSC) in vitro. Films are formed on 24-and 96well culture plates in the combinations: PEI, PAH, PEI-PSS, PEI-PSS-PAH, PEI-PSS-PEI. An analysis of the culture results show that direct contact of h-MSCs with the PEI surface promotes adhesion (93-95% of adhesive cells versus 40% in the control). On the PEI surface, h-MSCs are evenly distributed, form colonies and 80% monolayer after 72 h of culture, as in the control on culture plastic. On nanofilms from PAH and PEI-PSS-PAH, cells grow in the form of rosette-like colonies with long and thin processes similar to neurites. The cytotoxic properties of PSS were revealed in direct contact with h-MSCs (more than 40% of nonviable cells with damaged plasma membranes). On the PSS surface, cells lost their adhesiveness. To culture and stably grow the cell mass of h-MSCs, it is better to use monolayer nanofilms made of highly adhesive and non-toxic PEI polyelectrolyte, which can bind the growth factors of blood serum and platelet lysate, ensuring the growth of h-MSCs under in vitro deprivation conditions.

The effective development of thin oil rims by horizontal wells is an urgent area of technological development of oil and gas companies in the context of an increase in the portfolio of new fields with significant reserves of free gas. A key feature of the development of oil rims is gas coning and therefore it is necessary to limit the productivity of wells, which leads to a high sensitivity of project profitability to reservoir properties, economic conditions and the development system. For successful development it is necessary to optimize all the components of the project – wells count, downhole equipment, transport system. Some works relating to the theory and methodology of developing oil rims describe approaches to calculating the optimal well spacing [Khasanov et.al.], the number of wells per bush [Samolovov, Mozhchil et.al.], and ground facility [Povyshev et.al.]. Special cases of comparing different well placement systems are widely represented in the literature, for example, in [Sugaipov et.al.]. An increase in the share of oil rims production leads to the need to find common solutions to such optimization problems. In this paper, we consider the question of determining the optimal location of wells by systematic selection of an in-line or radial development system. When horizontal wells are placed on oil rims in the form of an in-line development system, optimal conditions are created for the uniform production of oil reserves, since the distance between the horizontal wells is the same for all cross sections of the well and the gas cone is formed uniformly along the direction of the horizontal wells. However, when combining well trajectories into one bush, in this case there is a need for large reach from the wellhead or in a small number of wells in the bush. When horizontal wells are placed on oil rims in radial development system, optimal conditions are created to minimize well reach, however, interference occurs between wells in the reservoir due to the distance between wells changing along the direction of the horizontal wellbore. The purpose of the work is to determine the conditions under which in-line or radial well placement is optimal.

No abstract