Effects of antioxidant state on individual susceptibility to silicosis (an experimental study)

The authors proved that animals having higher natural antioxidant activity and lower intensity of lipid peroxidation are more resistant to fibrogenic effects of quartz. The peritoneal macrophages obtained from those animals show higher resistance to quartz exposure "in vitro". Parameters characterizing antioxidant system should be included into a group of indexes describing propensity to silicosis.     

Are protein folds atypical?

Protein structures are a very special class among all possible structures. It has been suggested that a "designability principle" plays a crucial role in nature's selection of protein sequences and structures. Here, we provide a theoretical base for such a selection principle, using a simple model of protein folding based on hydrophobic interactions. A structure is reduced to a string of 0s and 1s, which represent the surface and core sites, respectively, as the backbone is traced. Each structure is therefore associated with one point in a high dimensional space. Sequences are represented by strings of their hydrophobicities and thus can be mapped into the same space. A sequence that lies closer to a particular structure in this space than to any other structures will have that structure as its ground state. Atypical structures, namely those far away from other structures in the high dimensional space, have more sequences that fold into them and are thermodynamically more stable. We argue that the most common folds of proteins are the most atypical in the space of possible structures.     

Percutaneous effects of iodine inhibit the development of experimental silicosis

Experiments on white rats proved that the silicotic pulmonary changes slowed with the tails periodically immersed into iodine solution. Those pulmonary changes were due to inhalation of quartzite dust and especially due to intratracheal administration of standardized quartz dust DQ12. Influenced by inhalation of dust containing quartz, the rats demonstrated characteristic alterations in cytologic features of bronchial and alveolar lavage water. The "iodine baths" also declined those alterations, that may prove higher resistance of pulmonary macrophages to cytotoxic effects of quartz. This hypothesis finds a support in experiments with culture of rat peritoneal macrophages. If incubated in a medium with low iodine concentrations and subsequently washed off, the macrophages demonstrate lower incidence of cytotoxic effects due to the next incubation with particles of DQ12. The macrophage's higher resistance against cytotoxic agents is believed to result directly in antisilicotic effect of iodine, so "iodine baths" could be recommended for pathogenetic therapy and medical prophylaxis of silicosis.     

Combined hyperlipidemia in transgenic mice overexpressing human apolipoprotein Cl

We have generated transgenic mice over-expressing human apolipoprotein CI (apo CI) using the native gene joined to the downstream 154-bp liver-specific enhancer that we defined for apo E. Human apo CI (HuCI)-transgenic mice showed elevation of plasma triglycerides (mg/dl) compared to controls in both the fasted (211 +/- 81 vs 123 +/- 52, P = 0.0001) and fed (265 +/- 105 vs 146 +/- 68, P < 0.0001) states. Unlike the human apo CII (HuCII)- and apo CIII (HuCIII)-transgenic mouse models of hypertriglyceridemia, plasma cholesterol was disproportionately elevated (95 +/- 23 vs 73 +/- 23, P = 0.002, fasted and 90 +/- 24 vs 61 +/- 14, P < 0.0001, fed). Lipoprotein fractionation showed increased VLDL and IDL + LDL with an increased cholesterol/triglyceride ratio (0.114 vs 0.065, P = 0.02, in VLDL). The VLDL apo E/apo B ratio was decreased 3.4-fold (P = 0.05) and apo CII and apo CIII decreased in proportion to apo E. Triglyceride and apo B production rates were normal, but clearance rates of VLDL triglycerides and postlipolysis lipoprotein "remnants" were significantly slowed. Plasma apo B was significantly elevated. Unlike HuCII- and HuCIII-transgenic mice, VLDL from HuCI transgenic mice bound heparin-Sepharose, a model for cell-surface glycosaminoglycans, normally. In summary, apo CI overexpression is associated with decreased particulate uptake of apo B-containing lipoproteins, leading to increased levels of several potentially atherogenic species, including cholesterol-enriched VLDL, IDL, and LDL.     

Lanthanides in phosphates with the structure of whitlockite mineral [analog of β-Ca3(PO4)2]

Data on phosphates with the structure of biogenic whitlockite mineral [analog of low-temperature modification of β-Ca₃(PO₄)₂] were analyzed. The possibility of isomorphic substitution of cations in phosphates with whitlockite structure was evaluated and formation of solid solutions of various compositions involving elements in oxidations states 1+, 2+, 3+, and 4+, including lanthanides and other elements and isotopes occurring in wastes from radiochemical plants, was studied. Phosphates of Ca, Mg, and lanthanides (Sm, Eu, Gd) were prepared by the sol-gel procedure, and their thermal, thermomechanical (thermal expansion), and hydrolytic properties were determined. The results of hydrothermal and thermal experiments were compared with published data for calcium phosphate and other matrices for immobilization of radioactive wastes (RAW).     

Influence of Heat Treatment on the Mechanical Characteristics of Diamond Powders

Powder Metallurgy and Metal Ceramics - Improvement in the efficiency of diamond tools is inextricably linked with the use of high-strength heat-resistant diamond grains for tooling. Hence, study of...     

Structure and Catalytic Activity of Poly(Titanium Oxide) Doped by Gold Nanoparticles in Organic Polymeric Matrix

The nanocomposite copolymers of poly(titanium oxide) (PTO) in an organic matrix of poly(hydroxyethyl methacrylate) (HEMA) doped by the Au nanoparticles (NPs) were synthesized in one-pot reaction. The composites were characterized as high optical transparence. It was proved by the SIMS, SAXS, and X-ray diffraction that PTO forms the 6 nm clusters uniformly distributed inside the organic polymer and chemically bonded to it. The AuNPs were formed by the UV irradiation of the copolymers containing the HAuCl₄ embedded into the reaction mixture before the synthesis. The primary structure of the PTO clusters is close to the anatase modification of crystalline TiO₂. This conclusion is made on the basis of agreement between the experimental FTIR spectra of the synthesized copolymers and the calculated IR spectra of the PTO/HEMA fragments calculated by the DFT quantum chemical methods and also by XPA-analysis. The synthesized materials have high photocatalytic activity. It has been shown by methylene orange decomposition under UV irradiation.     

Pilot study of countercurrent cold and mild heat extraction of sugar from sugar beets, assisted by pulsed electric fields

This study describes experiments on pulsed electric field (PEF)-assisted water extraction of sugar from sugar beet using a pilot countercurrent extractor with 14 extraction sections. Cossettes were prepared from sugar beet by industrial knives and PEF treatment of the cossettes was done with electric field strength E varied between 100 and 600 V/cm. The total time of PEF treatment was t_PEF = 50 ms. The effects of the main extraction parameters (temperature of extracting water and draft) on the extraction kinetics, as well as on the juice and cossette (pulp) characteristics, were investigated. The temperature of extraction from PEF-treated cossettes was varied from 30 to 70 °C; the draft was varied from 120 to 90%. The principal possibility of cold (at 30 °C) and moderate thermal (50-60 °C) extraction of sucrose from sugar beet cossettes treated by PEF was confirmed on the pilot countercurrent extractor. The purity of the juice obtained by cold and moderate thermal extraction was not lower than the purity of juice obtained by conventional hot water diffusion at 70 °C. The sugar beet pulp can be well exhausted by cold or mild thermal extraction of cossettes treated by PEF. Decrease of draft to 100-90% permitted increasing of the extracted juice concentration, but the cossettes were worse exhausted. The pulp obtained by cold extraction of PEF-treated cossettes had dryness >30%, which was noticeably higher than dryness of the pulp obtained by conventional hot water extraction technique.     

Inhibition of Neuronal Necroptosis Mediated by RIPK1 Provides Neuroprotective Effects on Hypoxia and Ischemia In Vitro and In Vivo

Ischemic brain injury is a widespread pathological condition, the main components of which are a deficiency of oxygen and energy substrates. In recent years, a number of new forms of cell death, including necroptosis, have been described. In necroptosis, a cascade of interactions between the kinases RIPK1 and RIPK3 and the MLKL protein leads to the formation of a specialized death complex called the necrosome, which triggers MLKL-mediated destruction of the cell membrane and necroptotic cell death. Necroptosis probably plays an important role in the development of ischemia/reperfusion injury and can be considered as a potential target for finding methods to correct the disruption of neural networks in ischemic damage. In the present study, we demonstrated that blockade of RIPK1 kinase by Necrostatin-1 preserved the viability of cells in primary hippocampal cultures in an in vitro model of glucose deprivation. The effect of RIPK1 blockade on the bioelectrical and metabolic calcium activity of neuron-glial networks in vitro using calcium imaging and multi-electrode arrays was assessed for the first time. RIPK1 blockade was shown to partially preserve both calcium and bioelectric activity of neuron-glial networks under ischemic factors. However, it should be noted that RIPK1 blockade does not preserve the network parameters of the collective calcium dynamics of neuron-glial networks, despite the maintenance of network bioelectrical activity (the number of bursts and the number of spikes in the bursts). To confirm the data obtained in vitro, we studied the effect of RIPK1 blockade on the resistance of small laboratory animals to in vivo modeling of hypoxia and cerebral ischemia. The use of Necrostatin-1 increases the survival rate of C57BL mice in modeling both acute hypobaric hypoxia and ischemic brain damage.     

Pattern of the atom ordering in a melt and surface properties of systems with intermetallic compounds

A local atomic structure of the Ni-Al, Ni-Ge, and Ni-Sn melts has been analyzed using the models reconstructed from experimental curves of the structure factor employing the reverse Monte Carlo and Voronoy-Delaunay methods. It has been found that a decisive effect on the formation of the short-range structure, type of the atomic interaction, and surface properties of melts of systems with intermetallic compounds is exerted by the retention of the component interaction intensity and the chemical bond type in melting intermetallic phases, which causes the correlation between the structures of the liquid and solid phases. A change in the pattern of the atom ordering in melts (an intensification of the interaction between like atoms, while the interaction between unlike atoms weakens in the Ni-Al → Ni-Ge → Ni-Sn order) results in the change of thermodynamic and surface properties of melts.