New Evidence on a Distinction between Aβ40 and Aβ42 Amyloids: Thioflavin T Binding Modes,Clustering Tendency,Degradation Resistance,and Cross-Seeding

The relative abundance of two main Abeta-peptide types with different lengths, Aβ40 and Aβ42, determines the severity of the Alzheimer’s disease progression. However, the factors responsible for different behavior patterns of these peptides in the amyloidogenesis process remain unknown. In this comprehensive study, new evidence on Aβ40 and Aβ42 amyloid polymorphism was obtained using a wide range of experimental approaches, including custom-designed approaches. We have for the first time determined the number of modes of thioflavin T (ThT) binding to Aβ40 and Aβ42 fibrils and their binding parameters using a specially developed approach based on the use of equilibrium microdialysis, which makes it possible to distinguish between the concentration of the injected dye and the concentration of dye bound to fibrils. The binding sites of one of these modes located at the junction of adjacent fibrillar filaments were predicted by molecular modeling techniques. We assumed that the sites of the additional mode of ThT-Aβ42 amyloid binding observed experimentally (which are not found in the case of Aβ40 fibrils) are localized in amyloid clots, and the number of these sites could be used for estimation of the level of fiber clustering. We have shown the high tendency of Aβ42 fibers to form large clots compared to Aβ40 fibrils. It is probable that this largely determines the high resistance of Aβ42 amyloids to destabilizing effects (denaturants, ionic detergents, ultrasonication) and their explicit cytotoxic effect, which we have shown. Remarkably, cross-seeding of Aβ40 fibrillogenesis using the preformed Aβ42 fibrils changes the morphology and increases the stability and cytotoxicity of Aβ40 fibrils. The differences in the tendency to cluster and resistance to external factors of Aβ40 and Aβ42 fibrils revealed here may be related to the distinct role they play in the deposition of amyloids and, therefore, differences in pathogenicity in Alzheimer’s disease.     

Effect of Dispersity and Porous Structure of TiO2 Nanopowders on Photocatalytic Destruction of Azodyes in Aqueous Solutions

Photocatalytic activity of TiO2 nanopowders of anatase modification with various particle sizes and specific surface areas has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue and direct blue 2C azodyes. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that TiO2 nanopowders have the particles size of 5-120 nm with the specific surface area of 15-120 m2·g^-1. The used TiO2 samples are characterized by mesoporous structures with average pore size of 4.3-14.9 nm. The photocatalytic activity of TiO2 was evaluated via decolorization of azodyes solutions. It was shown that the efficiency of decolorization symbatically changes with the dye adsorption value on TiO2 surface and the degree of decolorization rises when the surface area of TiO2 nanopowders increases. It was found that TiO2 photocatalytic activity essentially depends on adsorption interactions between the dye molecules and catalytic active centers on TiO2 surface, and these interactions, in turn, are greatly affected by pH of the solution.     

Mesoporous Structure and Photocatalytic Activity of Doped Polyanilines

Photocatalytic activity of doped polyaniline nanopowders with different molar ratio of An/O （aniline~oxidizer） has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that doped PANI （polyaniline） nanopowders have the particles size of 30-50 nm with the specific surface area of 20-35 m2.g＂~. It was found that PANI photocatalytic activity essentially depends on molar ratio of An/O and adsorption interactions between the dye molecules and catalytic active centers on PANI surface and these interactions are greatly affected by pH of the solution 9.2. An optimum of the synergetic effect is found for an initial molar ratio of aniline to oxidizer equal to 0.8.     

Noninvasive Surface Coverage Determination of Chemically Modified Conical Nanopores that Rectify Ion Transport

Surface modification will change the surface charge density (SCD) at the signal-limiting region of nanochannel devices. By fitting the measured i-V curves in simulation via solving the Poisson and Nernst-Planck equations, the SCD and therefore the surface coverage can be noninvasively quantified. Amine terminated organosilanes are employed to chemically modify single conical nanopores. Determined by the protonation-deprotonation of the functional groups, the density and polarity of surface charges are adjusted by solution pH. The rectified current at high conductivity states is found to be proportional to the SCD near the nanopore orifice. This correlation allows the noninvasive determination of SCD and surface coverage of individual conical nanopores.     

Scientific basis of effective energy resource use and environmentally safe processing of phosphorus-containing manufacturing waste of ore-dressing barrows and processing enterprises

Waste barrows of ore-dressing and processing enterprises have a special role among anthropogenic deposits where fine finders are stored, intensifying their amenability to wind and water erosion. Rock barrows occupy much larger territories than factory lands, leading to environmental pollution. Herein, we create a fundamental physical and chemical basis for the effective use of energy resources and environmentally safe processing of ore-dressing waste products, which allows for transformation of raw fine finders stored in tailing dumps into competitive products and decreases the amount of resources aimed toward ground disposal. It will also assure the extermination of tailing dumps and grounds. This can also minimize negative environmental impact and stabilize further development. For this purpose, a mathematical model of a complex chemical energy technological system (CETS) aimed at manufacturing phosphorite pellets has been developed. Large-scale models of multistage chemical energy technological processes of baking and coking moving dense multilayer masses of phosphorite pellets, which differ in their raw material physical, chemical, and granulometric characteristics, have also been developed. Additionally, special multilayer algorithms for formulating making decisions concerning optimal energy resource effectiveness management of CETS manufacturing phosphorite pellets have been developed. They differ in the quality ratings of the prepared pellets in the characteristics of raw phosphate materials. These calculations also consider the impact of controlling the actions of temperature and speed of gas supply for the exchange of having a dynamic dense multilayer pellets mass, which allows for using an available potential of increased effectiveness to maximize energy resources of CETS.

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Mixed hierarchical-functional fault models for targeting sequential cores

Current work presents a set of fault models allowing high coverage for sequential cores in systems-on-a-chip. We propose a novel approach combining a hierarchical fault model for functional blocks, a functional fault model for multiplexers and a mixed hierarchical-functional fault model for comparison operators, respectively. The fault models are integrated into a fast high-level decision diagram based test path activation tool. According to the experiments, the proposed method significantly outperforms state-of-the-art test pattern generation tools. The main new contribution of this paper is a formal definition of high-level decision diagram representations and the combination of the three fault models in order to target high gate-level stuck-at fault coverage for sequential cores.     

Determinants of Lipid Domain Size

Lipid domains less than 200 nm in size may form a scaffold, enabling the concerted function of plasma membrane proteins. The size-regulating mechanism is under debate. We tested the hypotheses that large values of spontaneous monolayer curvature are incompatible with micrometer-sized domains. Here, we used the transition of photoswitchable lipids from their cylindrical conformation to a conical conformation to increase the negative curvature of a bilayer-forming lipid mixture. In contrast to the hypothesis, pre-existing micrometer-sized domains did not dissipate in our planar bilayers, as indicated by fluorescence images and domain mobility measurements. Elasticity theory supports the observation by predicting the zero free energy gain for splitting large domains into smaller ones. It also indicates an alternative size-determining mechanism: The cone-shaped photolipids reduce the line tension associated with lipid deformations at the phase boundary and thus slow down the kinetics of domain fusion. The competing influence of two approaching domains on the deformation of the intervening lipids is responsible for the kinetic fusion trap. Our experiments indicate that the resulting local energy barrier may restrict the domain size in a dynamic system.