STUDY OF THE SOLUBILIZING CAPACITY OF POLYMER-COLLOID COMPLEXES FORMED WITH SODIUM ALGINATE AND CHLORIDE HEXADECYLPYRIDINIUM

It was examined the behavior of systems which contain surfactants and biopolymers is considered by the example of cationic surfactants and sodium alginate. The rheological and surface-active properties of the systems have been experimentally investigated. It was found that the presence of oppositely charged surfactants in the solution significantly affects the properties of sodium alginate, due to the fact that associates or polymer-colloidal complexes are formed in the solution. Their formation significantly affects the solubilizing ability in relation to non-polar liquids. Hydrodynamic parameters of macromolecules of sodium alginate in comparison with macromolecules of chitosan correspond to the conformation of the loose ball. The state of the SN is determined by the pH of the medium and temperature. The increase in temperature leads to a violation of the structure of the chain, its destruction and a subsequent decrease in viscosity. At a temperature of 293K, the macromolecule is in a more ordered state. In the alkaline environment there is a change in the conformation of the macromolecule. As a result of this change, the viscosity naturally increases. This is explained by the fact that in an alkaline environment, the macromolecule acquires an excess negative charge, there is a repulsion of the carboxyl groups of the same name in the chain links. The macromolecule acquires an expanded configuration. The viscosity increases. In acidic environment, sodium alginate has almost zero charge as a result of protonation of carboxyl groups. The molecule acquires the conformation of a loose ball with the lowest value of viscosity. The isoelectric state of the alginate macromolecule is observed in the pH range of 5.5 to 6.0. The described state of the macromolecule in solution is confirmed by our calculations. The interaction of surface-active cations with carboxyl groups of SN leads first to the formation of associates, then to polymer-colloidal complexes. The association as a result of electrostatic interaction of active groups is enhanced by the hydrophobic interaction of hydrocarbon fragments of surfactant molecules with each other and with the alginate matrix. The association ends with the formation of a polymer-colloidal complex.

Comparative Analysis of Molecular Properties and Reactions With Oxidants for Quercetin, Catechin and Naringenin

Flavonoids, a large group of secondary plant phenolic metabolites, are important natural antioxidants and regulators of cellular redox balance. The present study addressed the evaluation of the electronic properties of some flavonoids belonging to different classes: quercetin (flavonols), catechin (flavanols), and naringenin (flavanones) and their interactions with oxidants in the model systems of DPPH reduction, flavonoid autoxidation and chlorination. According to our ab initio calculations, the high net negative excess charges of the C rings and the small positive excess charges of the B rings of quercetin, catechin, and naringenin make these parts of flavonoid molecules attractive for electrophilic attack. The 3’-OH group of the B-ring of quercetin has the highest excess negative charge and the lowest energy of hydrogen atom abstraction for the flavonoids studied. The apparent reaction rates (M-1s-1, 20 ºC) and the activation energies (kJ/mol) of DPPH reduction are 4000±1000 and 23.0±2.5 in the case of quercetin, 1100±200 and 32.5±2.5 in the case of catechin, respectively. The stoichiometry of the DPPH – flavonoid reaction was 1:1. The activation energies (kJ/mol) of quercetin and catechin autoxidations were 50.8±6.1 and 58.1±7.2, respectively. Naringenin was not oxidized by the DPPH radical and air oxygen (autoxidation) and the flavonoids studied effectively prevented HOCl-induced hemolysis due to direct scavenging of hypochlorous acid (flavonoid chlorination). The best antioxidant quercetin has the highest value of HOMO energy, the planar structure and the optimal electron orbital delocalization on all phenolic rings due to C2=C3 double bond in the C ring (absent in catechin and naringenin).

Performance assessment of the atmospheric electric dowsing mechanism

The movement of the frame in the operator’s hand is provoked by the repulsion of the excess negative charge of air and the negative charge of the frame, equal in density to the charge of the Earth. A powerful increase in the repulsive forces is achieved due to the lever effect and is estimated by the ratio of the distance of the point on the horizontal knee to the radius of the vertical knee. Further strengthening is achieved by increasing the radius of the horizontal knee of the frame.

Physicochemical Properties and Surface Charge Characteristics of Arid Soils in Southeastern Iran

The majority of previous studies on surface charge characteristics were done on tropical and subtropical soils. Information of such studies in the arid regions is limited. A study was conducted to investigate the relation between soil chemical and mineralogical properties and surface charge characteristics of an arid region in Southeastern Iran. Eight soil pedons, representing the alluvial and the colluvial deposits, were described, and their mineralogical and physicochemical properties were examined. The common clay minerals in the studied area are smectite, palygorskite, kaolinite, chlorite, and illite. The point of zero charge (pH0) values are low (2.85–3.35) in all soils mostly affected by organic carbon (OC) and free iron oxide (Fed).pH0has a significant negative correlation with pH under field conditions (r=−0.45∗,P<0.05). The point of zero net charge (PZNC) levels for all the soils were <2, due to the excess negative charge in these soils. The estimated PZNC values were less thanpH0in all soils because of the high permanent negative charge in these soils. The permanent negative charge (σp) of the soils studied is high and it has a significant positive correlation with pH, CEC, Na, Mg, SAR, clay content, palygorskite, OC, andFed.

A Novel Gene Delivery System Targeting Urokinase Receptor

Recombinant proteins that combine different functions required for cell targeting and intracellular delivery of DNA present an attractive approach for the development of nonviral gene delivery vectors. Here, we described a novel protein termed ATF-lys10 which facilitated cell-specific gene transfer via receptor-mediated endocytosis. ATF-lys10 was composed of the amino-terminal fragment of urokinase and ten lysines at the carboxyl terminus. Bacterially expressed ATF-lys10 protein existed in soluble form, and had antigenicity of human urokinase. Purified ATF-lys10 specifically bound to uPAR-expressing cells and formed protein-DNA complexes with plasmid pGL3-control. After neutralization of excess negative charge with poly-L-lysine, these complexes served as a specific gene delivery vector for uPAR-expressing cells. Lysosomotropic compounds, such as chloroquine, drastically increased the ATF-lys10 mediated gene delivery efficiency. Our results suggest that the recombinant protein ATF-lys10 with the properties of DNA binding and tumor cell targeting represents a promising method for gene transfer and expression in tumor cells.

{Co(H2O)2[C6(COO)6]}n4n— — Ein neuartiges kettenförmiges Polyanion in Co3[C6(COO)6]·18H2O (Tricobalt(II)mellitat Octadecahydrat) / {Co(H2O)2[C6(COO)6]}n4n— – A Novel Chain-Like Polyanion in Co3[C6(COO)6]·18 H2O (Tricobalt(II) Mellitate Octadeca Hydrate)

Red orthorhombic single crystals of Co3[C6(COO)6]·18 H2O were grown in aqueous silica gel (space group Pbca, a = 852.7(2), b = 2015.6(3), c = 1712.3(3) pm, 269 parameters, 2675 reflections, Rg = 0.0217). The Co2+ ions are coordinated octahedrally by water molecules and oxygen atoms of carboxylate groups. Co(1) is bound to five water molecules and one carboxylate oxygen atom, Co(2) is situated on a crystallographic center of symmetry and coordinated by four carboxylate oxygen atoms and two water molecules. Folded chains extending parallel to [100] made up by Co(2) and mellitate hexaanions with composition {Co(H2O)2[C6(COO)6]}n4n— are the main feature of the crystal structure. The excess negative charge is compensated for by Co(1) cations bound to these chains via carboxylate groups related by a center of symmetry. Hydrogen bonds connect neighbouring chains primarily with carboxylate oxygen atoms which are not bound to Co2+ as the proton acceptors. Endothermic loss of water was observed to commence at 120 °C, followed (in air) by a further exothermic two step decomposition at 370 and 450 °C to yield Co3O4 as a crystalline residue. With (CH3)2SO a topotactical ligand exchange occurs without destruction of the single crystals causing the colour of the compound to change to deep-blue.

Impedance Spectroscopic Study of Zinc Oxide Varistors

ABSTRACTPolycrystalline zinc oxide containing oxides of bismuth, cobalt, manganese and antimony is found to exhibit highly non-ohmic I–V characteristic arising due to the presence of schottky barriers at the grain boundaries. Defect states present at the grain–grain boundary interfaces store excess negative charge and give rise to such potential barriers. Any improvement in the I–V characteristics therefore demands the understanding of grain boundary properties of the material. Impedance spectroscopy is found to separate grain and grain boundary contributions in a polycrystalline material and is used to determine grain boundary contributions towards the electrical behavior of the zinc oxide varistors. It also helps in identifying stored charges and defect states present and elucidates different trapping phenomena occurring at the interface behavior of zinc oxide varistors.

Further studies of a ferrous iron doped synthetic kaolin: dosimetry of X-ray induced defects

The structure of kaolin has been examined together with aspects of dosimetry and energy loss mechanisms of radiation to explain the formation of g = 2 EPR centres. The analysis points to the formation of a trapped hole on the ‘inner layer’ oxygen atoms of kaolin located at the boundaries between divalent ion and trivalent ion ‘cells’, in particular at the boundaries with excess negative charge. Direct interaction of X-rays with atoms and the possibility of proton recoil are eliminated. The means of production appears to be by transfer of charge following ionization of atoms by secondary electrons, with transfer of vacancies ultimately to the oxygen ions. Mechanisms which result in a decrease in signal strength with increase in concentration are examined. It is concluded that the cell mechanisms discussed are consistent with the rates of production and that at 20 Mrad (air) the number of centres should be reaching saturation.