Thermal conductivity vs depth profiling using the hot disk technique-Analysis of anisotropic, inhomogeneous structures

A recently developed method for analyzing the thermal conductivity vs depth variation near a sample surface has been extended to include inhomogeneous samples with anisotropy. If not considered, the anisotropy ratio in the sample structure can distort the depth-position data of the original test method. The anisotropy ratio is introduced in the original computational scheme in order to improve the depth-position estimations for inhomogeneous structures with anisotropy. The proposed approach has been tested in experiments and shown to improve depth position mapping.

Oligodendrocyte death and myelin loss in the cuprizone model: an updated overview of the intrinsic and extrinsic causes of cuprizone demyelination

The dietary consumption of cuprizone – a copper chelator – has long been known to induce demyelination of specific brain structures and is widely used as model of multiple sclerosis. Despite the extensive use of cuprizone, the mechanism by which it induces demyelination are still unknown. With this review we provide an updated understanding of this model, by showcasing two distinct yet overlapping modes of action for cuprizone-induced demyelination; 1) damage originating from within the oligodendrocyte, caused by mitochondrial dysfunction or reduced myelin protein synthesis. We term this mode of action ‘intrinsic cell damage’. And 2) damage to the oligodendrocyte exerted by inflammatory molecules, brain resident cells, such as oligodendrocytes, astrocytes, and microglia or peripheral immune cells – neutrophils or T-cells. We term this mode of action ‘extrinsic cellular damage’. Lastly, we summarize recent developments in research on different forms of cell death induced by cuprizone, which could add valuable insights into the mechanisms of cuprizone toxicity. With this review we hope to provide a modern understanding of cuprizone-induced demyelination to understand the causes behind the demyelination in MS.

ATPASE ERYTHROCYTE TRANSPORT SYSTEMS IN HUMAN BLOOD

Aim. The article deals with establishing the features of ATPase erythrocytes in the athletes of the first and second categories and non-athletes from different age groups. Material and methods. We studied the capillary blood of track-and-field athletes and healthy non-athletes of the same age and anthropometric characteristics (n = 60). Blood analysis was performed with the help of the Dixion hematological analyzer (Russia). The activity of erythrocyte membrane ATPases was studied according to K.S. Keeton. Results. The study revealed significant (p < 0.05) differences in certain (HGB and RBC) hematological blood indicators in participants from different age groups depending on their physical fitness. Age differences between groups are not significant (p > 0.05). The results obtained demonstrate the significantly (p < 0.001) higher values of ATPase activity in the athletes of the first and second categories from various age groups. The increase in Mg2+, Na+, K+-, Mg2+- and Na+, K+-ATPases activity in athletes is connected with more intensive metabolism in this group because transport ATPases participate in the energy supply of training and competition loads. Age-related differences (p < 0.05) in the activity of erythrocyte membrane ATPases in both groups can be possibly connected with the conformation features of erythrocyte membrane protein. The two-factor dispersion analysis revealed that age significantly (Р < 0.001) determined Mg2+, Na+, K+-, Mg2+- and Na+, K+-ATPases erythrocyte membrane activity at 89.15, 87.46, and 81.40 % respectively; physical activity at 96.19, 95.45 and 93.80 % respectively. Conclusion. General physical fitness and age can be considered as the factors determining the activity of erythrocyte membrane ATPases.

Practical Approach for Assessment of End-State Radiological Criteria for Remediation of Radioactively Contaminated Sites

An approach is described for assessment of the end state radiological criteria for remediation of radioactively contaminated sites. The target criteria are set in a form of prospective effective doses for members of the population who are subject to the higher exposures (representative persons). Brief review of international best practice in setting risk based remedial criteria is presented. The site-specific release criteria for activity concentrations in released material (e.g., Bq/g of soil) are derived using tabulated values of radionuclide activity from IAEA Safety Guide RS-G-1.7 (corresponding to the effective dose of 10 μSv/a). These tabulated values are scaled with the relevant target dose criteria for remediation of the specific site. Applicability and limitations (e.g., with regard to volume of released material) of proposed approach are discussed. The procedure for incorporating complimentary site-specific scenarios is described. The article further illustrates the approach by application of the methodology to the specific radioactively contaminated site (i.e., radioactive waste storage site with clean-up wastes of Chernobyl origin situated in Kiev Region). The proposed approach is generally applicable to a wide range of similar problems.

Thermal conductivity versus depth profiling of inhomogeneous materials using the hot disc technique

Transient measurements of thermal conductivity are performed with hot disc sensors on samples having a thermal conductivity variation adjacent to the sample surface. A modified computational approach is introduced, which provides a method of connecting the time-variable to a corresponding depth-position. This allows highly approximate-yet reproducible-estimations of the thermal conductivity vs. depth. Tests are made on samples incorporating different degrees of sharp structural defects at a certain depth position inside a sample. The proposed methodology opens up new possibilities to perform non-destructive testing; for instance, verifying thermal conductivity homogeneity in a sample, or estimating the thickness of a deviating zone near the sample surface (such as a skin tumor), or testing for presence of other defects.

Multi-electrode microbial fuel cell with horizontal liquid flow

A plug flow multi-electrode bioelectrochemical reactor for wastewater treatment and simultaneous generation of electricity has been developed and its efficiency investigated. It employs a horizontally located anodic zone in which the anodic electrodes comprise porous graphite plates coated with palladium. The aerated immersed cathodic electrodes contain iron(II) phthalocyanine as a catalyst. The parameters of the device were obtained using glycerol and acetate as fuels and anaerobic sludge as an inoculum. The maximal volumetric power and current densities obtained, relative to the total volume of the anodic zone, were: glycerol: 73+/-1 mA/L; 43+/-1 mW/L; acetate: 75+/-1 mA/L; 40+/-1 mW/L. It was shown that biotransformation of glycerol into volatile fatty acids does not depend on the presence of anodic electrodes in the reaction zone, while acetate degradation takes place only if the reaction zone contains anodic electrodes as a final electron acceptor.