Shock-Induced Damage Mechanism of Perineuronal Nets

The perineuronal net (PNN) region of the brain’s extracellular matrix (ECM) surrounds the neural networks within the brain tissue. The PNN is a protective net-like structure regulating neuronal activity such as neurotransmission, charge balance, and action potential generation. Shock-induced damage of this essential component may lead to neuronal cell death and neurodegenerations. The shock generated during a vehicle accident, fall, or improvised device explosion may produce sufficient energy to damage the structure of the PNN. The goal is to investigate the mechanics of the PNN in reaction to shock loading and to understand the mechanical properties of different PNN components such as glycan, GAG, and protein. In this study, we evaluated the mechanical strength of PNN molecules and the interfacial strength between the PNN components. Afterward, we assessed the PNN molecules’ damage efficiency under various conditions such as shock speed, preexisting bubble, and boundary conditions. The secondary structure altercation of the protein molecules of the PNN was analyzed to evaluate damage intensity under varying shock speeds. At a higher shock speed, damage intensity is more elevated, and hyaluronan (glycan molecule) is most likely to break at the rigid junction. The primary structure of the protein molecules is least likely to fail. Instead, the molecules’ secondary bonds will be altered. Our study suggests that the number of hydrogen bonds during the shock wave propagation is reduced, which leads to the change in protein conformations and damage within the PNN structure. As such, we found a direct connection between shock wave intensity and PNN damage.

Structure and germicidal property of a novel guanidine organomercury complex

A novel guanidine organomercury complex 1, [HgCl(DNP)]·CH5N3·CH3CN 1 (DNP = 2,4- dinitrophenol), has been synthesized. Each mercury(II) atom is tricoordinated to one chlorine atom, one carbon atom of the benzene ring, and one oxygen atom from 2, 4-dinitrophenol. The coordination arrangement around the mercury atom is Y-shaped. This is the first structural report on an organomercury derivative of 2, 4-dinitrophenol and guanidine. The distance of Hg-Cl between the two Hg ions groups is 3.272 Å, which indicates the presence of weak Hg···Cl interactions. Secondary bonds make complex 1 form 3D interspersed network structure, which is 2D [HgCl(DNP)CH5N3]n plane and 1D solvent [(CH3CN)2]∞ broadband. The antibacterial activity of 1 were studied. It shows complex 1 has very good bactericidal activity, and is also a potential antimicrobial agents.

COMPOSITION AND STRUCTURE OF THE DISPERSE ZONE OF WEATHERING CRUST OF GRANITOIDS OF THE TERRITORY OF THE CITY OF CHELYABINSK

Residual clay soils are the bases of industrial and civil buildings and structures in the Urals region. Therefore, the study of the composition, structure and properties of residual soils, serving as the bases for projected and under construction objects, is a primary task that contributes to a more rational conduct of all types of engineering surveys. The paper examines the results of investigation of structural strength, chemical and mineral compositions of residual clayey soils of the dispersed zone of the granitoids weathering crust of the Chelyabinsk pluton, their macro- and microstructure. According to the data of the investigations carried out, the dispersed zone of the weathering crust was subdivided into smaller subdivisions. Varieties in the thickness of residual clay soils are distinguished on the basis of qualitative (color, structural and texture features) and quantitative (physical and mechanical properties, structural strength) characteristics. Moreover, an attempt has been made to scientifically substantiate the isolation of varieties in the thickness of residual clay soils from the results of studying structural strength. Based on the analysis of the obtained results of studies, taking into account the classifications of different regulatory sources, the author shares in the general case the dispersed zone of the weathering crust according to the degree of structural strength into three varieties: structureless (residual clayey soil with secondary structural bonds acquired as a result of hypergenesis), weakly structural (weaklyclayey soil, which has strongly attenuated primary and also partially secondary bonds) and a structurally stable (residual clayey soil with strongly attenuated primary bonds). However, the conclusions drawn need to be confirmed through more studies, since the geotechnical information obtained as a result of the present study of the composition and structure of the dispersed zone of the weathering crust of granitoids of the Chelyabinsk batholith at three points is not enough.

Development and Characterization of Teflon-Copper Composite Material

Composites are the combination of materials that are mixed together to achieve specific structural properties. Teflon (Polytetrafluoroethylene PTFE) consists of long-chain molecular structure. Its monomer consists of two carbon atoms each of them having flourine atoms attached. Bonds within each chain are strong covalent bonds where as the secondary bonds between two chains are weaker. By raising temperature, the distance between the chains increases providing good adjustment of the atoms of other materials due to anisotropy of its mechanical properties. Powder metallurgy technique using hot isostatic pressing, a hybrid densification process in which pressure and temperature are applied at the same time, has been used to develop a teflon-copper composite material. Three samples were prepared by changing the teflon-copper composition as 60:40%, 65:35% and 70:30% by weight. Commercially available powders of teflon and copper of grain size ~ 40 μm was used. The aim to develop this type of material was to increase its density (~ 4 g/cm3), and hardness. The commercial applications of such type of composite material are solid lubricants, sleeves, bearings etc. In this paper the effect of composition on hardness, tensile strength and surface roughness is studied.

Synthesis and X-ray Characterization of Organotelluroxane

The reactions of diethyl tellurium (IV) diiodide [(C2H5)2TeI2 ] with conc. HNO3 afford diorganotelluroxane. The X-ray crystal structures of organotelluroxane reveal the immediate co-ordination geometry about the central tellurium atom to be pseudotrigonal bipyramidal ( TBP) with one stereochemically active electron lone pair. The supramolecular associations of the diorganotelluroxanes (IV) generated through Te---O secondary bonds.

Bond-length distributions for ions bonded to oxygen: results for the non-metals and discussion of lone-pair stereoactivity and the polymerization of PO4

Bond-length distributions are examined for three configurations of the H+ ion, 16 configurations of the group 14–16 non-metal ions and seven configurations of the group 17 ions bonded to oxygen, for 223 coordination polyhedra and 452 bond distances for the H+ ion, 5957 coordination polyhedra and 22 784 bond distances for the group 14–16 non-metal ions, and 248 coordination polyhedra and 1394 bond distances for the group 17 non-metal ions. H...O and O—H + H...O distances correlate with O...O distance (R 2 = 0.94 and 0.96): H...O = 1.273 × O...O – 1.717 Å; O—H + H...O = 1.068 × O...O – 0.170 Å. These equations may be used to locate the hydrogen atom more accurately in a structure refined by X-ray diffraction. For non-metal elements that occur with lone-pair electrons, the most observed state between the n versus n+2 oxidation state is that of highest oxidation state for period 3 cations, and lowest oxidation state for period 4 and 5 cations when bonded to O2−. Observed O—X—O bond angles indicate that the period 3 non-metal ions P3+, S4+, Cl3+ and Cl5+ are lone-pair seteroactive when bonded to O2−, even though they do not form secondary bonds. There is no strong correlation between the degree of lone-pair stereoactivity and coordination number when including secondary bonds. There is no correlation between lone-pair stereoactivity and bond-valence sum at the central cation. In synthetic compounds, PO4 polymerizes via one or two bridging oxygen atoms, but not by three. Partitioning our PO4 dataset shows that multi-modality in the distribution of bond lengths is caused by the different bond-valence constraints that arise for Obr = 0, 1 and 2. For strongly bonded cations, i.e. oxyanions, the most probable cause of mean bond length variation is the effect of structure type, i.e. stress induced by the inability of a structure to follow its a priori bond lengths. For ions with stereoactive lone-pair electrons, the most probable cause of variation is bond-length distortion.