The evolution of pre-operative spine tumour embolization

Pre-operative spine tumour embolization is a useful adjunct to minimize operative complications and blood loss during complex resections. While the efficacy of this procedure has been well studied, relatively little is documented regarding how to optimize technical parameters for tumour characteristics. This pictorial case series seeks to review our centre’s experience over the last decade in using a range of embolization techniques. As experience with this procedure has matured, we propose an approach based on the patient’s vascular anatomy and tumour angioarchitecture. This includes the use of coils as protective barriers rather than primary embolics; particle embolization to permeate fine capillary networks; consideration for liquid embolic agents in the presence of large caliber tumour vessels with associated arteriovenous shunting; and percutaneous intralesional embolization when endovascular access is insufficient to achieve the desired outcome. In many cases, a combination of these methods is needed, and close communication with the surgeon ensures the best outcome. Despite these advances, continued work is needed to determine how to optimize complete devascularization, and thus surgical benefit, while safely sparing critical neuroanatomical structures.

EVALUATION OF SORPTION MOISTENING IN RESEARCH OF MOISTURE-CAUSED DEFORMATIONS OF BUILDING MATERIALS

Investigation methods described in literature and standards do not evaluate the influence of sorption moisture upon moisture-caused deformations of building materials. Therefore, the usual deformations measuring methods had to be amended by measuring moisture deformations in various models and by setting sorption moisture. The improved methods was applied for solving the tasks of durability of articles. The basic point of the developed methods intended for investigating the moisture-caused deformations is investigation of the groups of specimens by measuring deformations in the environment of fixed sorption moisture using four models. According to the methods described in this article, the dependence of deformations (eu) of various construction materials (concrete, porous concrete, sand-lime and ceramic bricks, cement-lime plasters) upon moisture and changes therein was investigated: eu = f(u). Analysing the materials with different capillary structures enables us to provide—in a very concise form—some References concerning value and nature of deformations. Linear moisture-caused deformations of basic construction materials (concrete, sand-lime and ceramic bricks, cement-lime plasters, porous concrete) vary within the limits of 0,33—0,77 mm/m. In case of articles containing organic fillings they can reach up to 6 mm/m. When the material is of a fine capillary structure the highest relative moisture elongation K of a material is observed in the environment of vapour area. Relative moisture elongation of the tested materials with the outset of intense capillary condensation varies from 0,05 mm/(mx%) to 0,51 mm/(mx%).

Efficiency of Pumping and Power Generation in Ultrafine Electrokinetic Systems

In this paper, some of the practical implications of the theory of electrokinetic flow in ultrafine capillaries are examined. It is found that electroosmotic pumping efficiency can exceed mechanical pumping efficiency when the width of capillary elements become small. Computations show that electric power generation with an efficiency of approximately 17 percent may be obtained by pumping water through fine capillary media.