Effect of low temperatures and ionizing irradiation upon physical-mechanical properties and connective-tissue structures of porcine fibrous pericardium and aortic valve leaflets

Xenogeneic tissue devitalization is one of the creating methods of the tissuereplacing the biocompatible cell-free shells for the regenerative surgery. The work describes the possibility of applying the complex approach based on the continuous usage of cryo and radioactive (electron irradiation exposure) biological tissue damage effects. The pre-implant treatment provides sterilization and a possibility for the low temperature preservation of xenografts. After the transplantation such a cell-free xenoscaffold can be gradually replaced with the autogenic extracellular matrix from the recipient’s cells and forms a stable long-term structure of the biological prosthesis. Fibrous pericardium (FP) and aortic valve leaflets (AVLs) were extracted from the mature pig. The prepared tissues were rinsed with the sterile normal saline solution and frozen down to the liquid-nitrogen temperature. After one time placing on water-bath (37°C) they were exposed to electron irradiation within dosage range of 25-30 kGray and submerged into the liquid nitrogen vapors. After influence of low temperature and ionizing radiation, tissue morphological structure was assessed using the optical microscopy. Deformations, i.e. longitudinal and transverse monoaxial strength were performed to calculate the physical and mechanical properties of FP and AVLs. Such a devitalization method of the FP and AVLs causes significant destructive changes in cell elements, however the spatial arrangement and structural integrity of the connective tissue fiber are preserved. Joint impact of low temperatures and ionizing radiation gives the synergetic effect, increasing the strength and elastic tissue properties. Freezing down to –196 °C and electron irradiation initiate formation of the intra- and intermolecular transverse cross-linking due to the binding activity of fibrous proteins. It leads to a more dense arrangement of the collagen fiber, adds strength to the implant and provides the structural tissue stabilization. The authors believe that during the remodeling in the recipient organism, the biomaterial structure modified in such a manner can successfully prevent physiological tension

Creation of functional solid-state composites based on black peat

The paper presents investigations of composite materials based on black peats of Barabinskoe and Taganskoe deposits of the Tomsk region and carboxymethyl cellulose, both modified with iron (Ш) and copper (II) chloride solutions. In order to improve hydrophobic properties of compositions, optimum salt concentrations are detected. Water sorption and desorption isotherms are obtained for modified specimens. It is suggested to employ synthesized solid-state compositions as insulators in the capacity of both humidity controller and indoor-contaminant absorber

Study of absorption of organic pollutants by modified natural materials

The paper presents the study of the absorption mechanism of organic pollutants such as formaldehyde and oxalic acid by natural zeolite and peat materials modified by iron (III) ions using the limited volume method.The relevance of this paper is a search for the use of inexpensive and available natural sorbents for waste water purification from ecologically hazardous water-soluble organic pollutants. The impact produced by the solution concentration and temperature and the size of natural composite particles on the sorption rate of organic substances is described in this paper. The effective factors for diffusion and energy of the process activation are calculated. It is found that the mixed-diffusion kinetics is the determinant stage of the process. In case of peat and zeolite composites, the internal diffusion prevails in the mixed-diffusion kinetics

Study of absorption of organic pollutants by modified natural materials

The paper presents the study of the absorption mechanism of organic pollutants such as formaldehyde and oxalic acid by natural zeolite and peat materials modified by iron (III) ions using the limited volume method.The relevance of this paper is a search for the use of inexpensive and available natural sorbents for waste water purification from ecologically hazardous water-soluble organic pollutants. The impact produced by the solution concentration and temperature and the size of natural composite particles on the sorption rate of organic substances is described in this paper. The effective factors for diffusion and energy of the process activation are calculated. It is found that the mixed-diffusion kinetics is the determinant stage of the process. In case of peat and zeolite composites, the internal diffusion prevails in the mixed-diffusion kinetics

Creation of functional solid-state composites based on black peat

The paper presents investigations of composite materials based on black peats of Barabinskoe and Taganskoe deposits of the Tomsk region and carboxymethyl cellulose, both modified with iron (Ш) and copper (II) chloride solutions. In order to improve hydrophobic properties of compositions, optimum salt concentrations are detected. Water sorption and desorption isotherms are obtained for modified specimens. It is suggested to employ synthesized solid-state compositions as insulators in the capacity of both humidity controller and indoor-contaminant absorber