The in vitro generation of a bioartificial cardiac construct (CC) represents a promising tool for the repair of ischemic heart tissue. Several approaches to engineer cardiac tissue in vitro have been conducted. The main drawback of these studies is the insufficient size of the resulting construct for clinical applications. The focus of this study was the generation of an artificial three-dimensional (3D), contractile, and suturable myocardial patch by combining a gel-based CC with decellularized porcine small intestinal submucosa (SIS), thereby engineering an artificial tissue of 11 cm2 in size. The alignment and morphology of rat neonatal cardiomyocytes (rCMs) in SIS-CC complexes were investigated as well as the re-organization of primary endothelial cells which were co-isolated in the rCM preparation. The ability of a rat heart endothelial cell line (RHE-A) to re-cellularize pre-existing vessel structures within the SIS or a biological vascularized matrix (BioVaM) was determined. SIS-CC contracted spontaneously, uniformly, and rhythmically with an average rate of 200 beats/min in contrast to undirected contractions observed in CC without SIS support. rCM exhibited an elongated morphology with well-defined sarcomeric structures oriented along the longitudinal axis in the SIS-CC, whereas round-shaped and random-arranged rCM were observed in CC. Electric coupling of rCM was demonstrated by microelectrode array measurements. A dense network of CD31+/eNOS+ cells was detected as permeating the whole construct. Superficial supplementation of RHE-A cells to SIS-CC led to the migration of these cells through the CC, resulting in the re-population of pre-existing vessel structures within the decelluarized SIS. By infusion of RHE-A cells into the BioVaM venous and arterial pedicles, a re-population of the BioVaM vessel bed as well as distribution of RHE-A cells throughout the CC was achieved. Rat endothelial cells within the CC were in contact with RHE-A cells. Ingrowth and formation of a network by endothelial cells infused through the BioVaM represent a promising step toward engineering a functional perfusion system, enabling the engineering of vascularized and well-nourished 3D CC of dimensions relevant for therapeutic heart repair.
Abstract Poly-L-lactic acid (PLLA) has been produced by ring-opening polymerization method. During the polymerization processes different temperatures and process times have been applied to reach an optimum setup that was used to produce sample. The sample was measured by Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) methods to identify the structure, molar mass and define the glass transition temperatures of product and obtain general information about the physical and chemical properties of material. Based on the results of measures, the material’s crystallinity was also investigated. The plasticization of PLLA has been also investigated. During the experiments, previously produced material (PLLA synthesized by polycondensation) was plasticised by adding of glycerol-dioleate. The plasticized material was also measured by FTIR, GPC and DSC methods to check the basic physical and chemical parameters of the material. According to the results of the measurements that were found, by this approach, the glass transition temperature of PLLA was reduced by 7 °C that indicated the glycerol-dioleate might act as a plasticizer for PLLA material without any deviation in the chemical structure of material.
A building with a double inclined roof is a more complicated structure than a blockhouse. The air termination system consists of several types of conductors. The ridge conductor is a constant element of air termination systems. The collection space consists of two parts. That of the plane of the roof is separated from the collection space of the ridge conductor by a bent surface, whose directrix is an ellipse or a hyperbola, depending on the polarity. Then the border follows the bisector until it intersects with the perpendicular plane coming from the eaves. Under the effect of the metal flange plate along the eaves, the collection space of the roof decreases. On the outside of these planes, additional parts of collecting space are associated with the unprotected edges. The average stroke-free period between shielding failures is plotted against the height h of the eaves of a double inclined roof.
Abstract Objective Rituximab is a therapeutic anti‐CD20 antibody used for in vivo depletion of B cells in proliferative and autoimmune diseases. However, the mechanisms of action are not fully understood, since not all of the therapy‐mediated effects can be explained by the depletion of antibody‐secreting cells. In addition to B cells, there is also a small population of T cells coexpressing CD20 in all individuals. This study was conducted to examine the phenotype and function of CD3+CD20+ T cells in patients with rheumatoid arthritis (RA) and healthy controls. Methods The phenotype and apoptosis of peripheral blood mononuclear cells from healthy donors and RA patients were examined by 4‐color fluorescence‐activated cell sorting analyses. Cytokine production was determined by intracellular staining and measurement of cytokines in the supernatants. Proliferation of sorted T cell populations was analyzed using 3 H‐thymidine uptake assays. Results In healthy individuals, 0.1–6.8% of peripheral blood T cells (mean 1.6%; n = 142) coexpressed CD20, which was not significantly different from that in the peripheral blood of RA patients, in whom 0.4–2.6% of T cells (mean 1.2%; n = 27) were CD20+. During rituximab therapy, the CD20+ T cells along with the B cells were eliminated from the RA peripheral blood. Among the CD20+ T cells, 45% coexpressed CD8 and 55% coexpressed CD4. Polyclonal CD3+CD20+ cells were functionally characterized by constitutive cytokine production (i.e., interleukin‐1β and tumor necrosis factor α), a low proliferative capacity, a high activation state, and enhanced susceptibility to apoptosis. Conclusion These findings suggest that CD20+ T cells represent a terminally differentiated cell type with immune‐regulatory and proinflammatory capacities. Depletion of CD20+ T cells may be an additional mechanism by which anti‐CD20 therapy functions in patients with RA.
The point of strike is determined when the first connecting leader starts upward from the earth or from any earth structure against the approaching leader. In the case of several connecting leaders, different striking points can occur but the orientation point should not change. The intertwining of lightning paths verifies that the downward leader and the connecting leader join at the place marked by the red arrow. The orientation distance is the gap between the orientation point and the expected point of strike. In the case of orientation distance, the probability of occurrence can be expressed by logarithmic normal distribution. Between the orientation point and the point of strike, the downward leader and the connecting leader propagate against each other. The same process occurs in a discharge between electrodes energised with an impulse voltage in the laboratory.
Current produces a magnetic field around the conductor in which it is flowing. The intensity of the field is expressed by the magnetic flux density B (Vs/m2), which is a vector directed tangential on a circle around the conductor. On performing the integration, the mutual inductance M is also obtained between the rectangular loop and the infinite long conductor. The fluxes are positive with the indicated directions of the current. A polygonal loop can always be divided into triangles that represent basic elements for general use in the calculation of induced voltages. In the case of a direct stroke, the path of the lightning current is taken as being along an infinite vertical line.
The protection angle proved to be suitable for high voltage lines up to now. The standardized method involves much problems and contradictions applying to three-dimensional structures. Therefore, it should be restrictively used as an additional method for design air-termination systems.
