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Journal articles on the topic 'Polyvalent metals'

Author: Grafiati

Published: 30 May 2022

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1

Grosdidier, B., A. Ben Abdellah, and J. G. Gasser. "Experimental ordering potential of manganese-polyvalent metals." Journal of Non-Crystalline Solids 353, no. 32-40 (October 2007): 3069–73. http://dx.doi.org/10.1016/j.jnoncrysol.2007.05.068.

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2

Kiselev, A. I. "Dynamic characteristics of the melts of polyvalent metals." High Temperature 49, no. 3 (June 2011): 363–68. http://dx.doi.org/10.1134/s0018151x11030084.

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3

Kiselev, A. I., and V. I. Kononenko. "Correlation energy and the superconductivity of polyvalent metals." Russian Metallurgy (Metally) 2006, no. 4 (August 2006): 358–62. http://dx.doi.org/10.1134/s0036029506040148.

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4

Lai, S. K., P. J. Hsu, K. L. Wu, W. K. Liu, and M. Iwamatsu. "Structures of metallic clusters: Mono- and polyvalent metals." Journal of Chemical Physics 117, no. 23 (December 15, 2002): 10715–25. http://dx.doi.org/10.1063/1.1521128.

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5

Colinet, C., A. Bessoud, A. Pasturel, and P. Hicter. "On the partial excess entropies of transition metals in liquid polyvalent metals." Physica B+C 133, no. 2-3 (December 1985): 103–8. http://dx.doi.org/10.1016/0378-4363(85)90404-8.

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6

Gohil, D. R., P. N. Vyas, N. K. Bhatt, and P. R. Vyas. "Electrical Transport in Polyvalent Liquid Bismuth and Antimony Metals." Journal of Nano- and Electronic Physics 12, no. 2 (2020): 02032–1. http://dx.doi.org/10.21272/jnep.12(2).02032.

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7

Turaev, Abbaskhan Sabirkhanovich, and Al'bina Vasil'yevna Filatova. "INVESTIGATION OF THE PROCESS OF CHEMICAL CROSSLINKING OF NA-CMC POLYVALENT METAL IONS." chemistry of plant raw material, no. 4 (December 21, 2020): 93–100. http://dx.doi.org/10.14258/jcprm.2020046952.

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This article is devoted to the study of the Na-CMC structuring process under various conditions: structuring with polyvalent metal ions, structuring with polyvalent metal ions in the presence of polybasic acids. Structuring in a Na-CMC solution was investigated by adding polyvalent metal ions to it at various ratios Me+p / COO-, pH, which allowed us to characterize the structuring process as a reaction of macromolecules with low molecular weight compounds.It was found that the probability of intermacromolecular crosslinking, responsible for gelation, increases with an increase in the initial concentration of Na-CMC solution and with the additional presence of polybasic acids. When salts of polyvalent metals interact with solutions of polybasic acids in the presence of a 2N NaOH solution, their complex salts are formed.Titration calculations and IR spectra of dried salts confirmed the conclusion made about the formation of salts of structure I, II, III, IV. Crosslinking of Na-CMC has been shown to occur via compounds of the M2+ (3+) - OOS-R-type. It has been established that strong, transparent jellies are formed by trivalent metal ions, divalent metal ions also form brittle, cloudy jellies that stratify during a day.A suggestion has been made that the main reaction during gelation of the Na-CMC solution is the interaction of -COOH groups along the chain of the Na-CMC macromolecule with the Al+3 salt and citric acid of structure III. The role of citric acid is that it is a transverse bridge in the binding of Na-CMC macromolecules. During the process of chemical crosslinking, the system turns from a fluid state into a non-fluid one, and the dynamic viscosity of the system increases from 3.548 Pa·s to 1585 Pa·s.

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8

Jank, W., and J. Hafner. "Trends in the electronic structure of the polyvalent liquid metals." Journal of Non-Crystalline Solids 117-118 (February 1990): 304–7. http://dx.doi.org/10.1016/0022-3093(90)90938-i.

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9

Bhuiyan, G. M., and Fysol Ibna Abbas. "Local minimum in pair potentials of polyvalent metals: A limitation of pseudopotential theory." International Journal of Modern Physics B 33, no. 07 (March 20, 2019): 1950049. http://dx.doi.org/10.1142/s0217979219500498.

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Local minimum appearing in the interionic pair potentials, when derived from local model pseudopotential, for Al (and some other polyvalent metals) remains as a long standing problem of clear understanding of its origin, although some attempts have been made by a few authors. The origin of this feature of local minimum is systematically investigated for the first time in this paper considering both the core size and the conduction electron density as variables. Interionic pair potential is derived from Ashcroft’s empty core model because it depends on these two variables only. Results of this investigation show monovalent metals do not exhibit a local minimum at all but trivalent Al and some other polyvalent metals do exhibit at their normal densities. Here, the combined effect of the core size and the conduction electron density results whether the local minimum will appear or not. More interestingly, for smaller core size, conduction electron density plays major role and for larger core size the core radius plays the major role in determining the depth of the local minimum.

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10

Yokoyama, I., and S. Ono. "Effective interatomic pair potentials in liquid polyvalent metals from observed structure data." Journal of Physics F: Metal Physics 15, no. 6 (June 1985): 1215–28. http://dx.doi.org/10.1088/0305-4608/15/6/008.

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11

Huttner, B. "Optical properties of polyvalent metals in the solid and liquid state: lead." Journal of Physics: Condensed Matter 7, no. 5 (January 30, 1995): 907–18. http://dx.doi.org/10.1088/0953-8984/7/5/013.

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12

Huttner, B. "Optical properties of polyvalent metals in the solid and liquid state: aluminium." Journal of Physics: Condensed Matter 6, no. 13 (March 28, 1994): 2459–74. http://dx.doi.org/10.1088/0953-8984/6/13/008.

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13

Knupfer, M., K. Widder, M. Sing, O. Knauff, and J. Fink. "Influence of the core polarization on the dielectric properties of polyvalent metals." European Physical Journal B 6, no. 3 (November 1998): 323–28. http://dx.doi.org/10.1007/s100510050556.

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14

Indlekofer, G., A. Pflugi, P. Oelhafen, D. Chauveau, C. Guillot, and J. Lecante. "Electronic structure of liquid polyvalent metals studied by synchrotron radiation photoelectron spectroscopy." Journal of Non-Crystalline Solids 117-118 (February 1990): 351–54. http://dx.doi.org/10.1016/0022-3093(90)90950-q.

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15

Sorkina, N. S., L. P. Kuzmina, L. A. Dueva, T. B. Burmistrova, T. Yu Stasenkova, V. A. Stesikova, O. I. Rumyantseva, S. G. Komarova, L. V. Khabusova, and L. M. Bezrukavnikova. "Pathomorphology of bronchopulmonary diseases in workers exposed to colored metal aerosols." PULMONOLOGIYA, no. 4 (August 28, 2008): 81–85. http://dx.doi.org/10.18093/0869-0189-2008-0-4-81-85.

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Etiopathogenic features and diagnostic criteria of occupational diseases studying in workers engaged in colored metallurgy have been given in the paper. Polyvalent sensitization to metal allergens (nickel, chrome, beryllium, manganese) was found. A toxic effect of nickel on DNA was shown that could be used as a biomarker of exposure for biological monitoring in colored metallurgy workers. Biochemical investigations determined the main pathogenic mechanisms underlying pathomorphology of bronchopulmonary diseases caused by the exposure of colored metals, such as activation of lipid peroxidation, "proteolysis – antiproteolysis" imbalance, growing significance of infection. This is the first study demonstrating clinical and biochemical parallels between characteristics of development and course of respiratory pathology caused by the exposure of colored metals. Infectious, inflammatory, toxico-allergic, and destructive processes predominated in this pathology. Preventive and rehabilitation strategies have been developed.

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16

Alieva, Dj E., A. Y. Kiiikbaeva, and D. A. Moldokanova. "PECTIN SUBSTANCES." Herald of KSUCTA, №2, Part 1, 2022, no. 2-1-2022 (April 30, 2022): 517–22. http://dx.doi.org/10.35803/1694-5298.2022.2.517-522.

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This article provides information about pectin substances. Information is given on the chemical structure of pectin macromolecules, their physiological activity and physicochemical properties. Clause contains the data, concerning applications of pectin in medicine and pharmacology. Pectin is effective detoksicant, possesses selective properties in relation to cations polyvalent, heavy and radioactive metals. It is used as plasmasubstitude of gemostatika.

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17

Oelhafen, P., G. Indlekofer, and H. J. Güntherodt. "Valence Electron Structure of the Heavy Polyvalent Liquid Metals from Mercury to Bismuth*." Zeitschrift für Physikalische Chemie 157, Part_2 (January 1988): 483–88. http://dx.doi.org/10.1524/zpch.1988.157.part_2.483.

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18

Shanker, G., and K. N. Khanna. "Thermal Pressure Coefficients, of Liquid Polyvalent Metals Based on One-Component Plasma Model." Physics and Chemistry of Liquids 16, no. 4 (May 1987): 307–11. http://dx.doi.org/10.1080/00319108708078532.

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19

Avte, R. S., P. N. Gajjar, and A. R. Jani. "Contribution of a Point Defect to the Electrical Resistivity of Some Polyvalent Metals." physica status solidi (b) 176, no. 2 (April 1, 1993): K59—K61. http://dx.doi.org/10.1002/pssb.2221760232.

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20

Lai, S. K., W. D. Lin, K. L. Wu, W. H. Li, and K. C. Lee. "Specific heat and Lindemann-like parameter of metallic clusters: Mono- and polyvalent metals." Journal of Chemical Physics 121, no. 3 (July 15, 2004): 1487–98. http://dx.doi.org/10.1063/1.1763144.

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21

Fabian, J., and S. Das Sarma. "Spin Relaxation of Conduction Electrons in Polyvalent Metals: Theory and a Realistic Calculation." Physical Review Letters 81, no. 25 (December 21, 1998): 5624–27. http://dx.doi.org/10.1103/physrevlett.81.5624.

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22

Mazidji, C. N., B. Koopman, and G. Bitton. "Chelating Resin versus Ion-Exchange Resin for Heavy Metal Removal in Toxicity Fractionation." Water Science and Technology 26, no. 1-2 (July 1, 1992): 189–96. http://dx.doi.org/10.2166/wst.1992.0399.

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A chelating resin (Chelex 50-100) and ion-exchange resin (Dowex 50W-X8) were evaluated for removal of heavy metals in toxicity fractionation. Microtox and β-galactosidase activity were employed as toxicity endpoints. The resins were packed into 4 raL glass Pasteur pipettes for use. Chelating resin provided complete removal of toxicity due to polyvalent heavy metal cations (Cd, Cu, Hg, Pb, Zn). Ion-exchange resin was ineffective in removing mercury toxicity. Neither resin provided complete removal of Ag+ toxicity. Toxicity of organic compounds was, at most, partially removed. Performance of the ion-exchange and chelating resins was insensitive to hardness and pH. Based on these results, chelating resin is recommended for heavy metal removal as part of a toxicity fractionation procedure.

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23

Sun, Mingjing, Zhongqi He, and Deb P. Jaisi. "Role of metal complexation on the solubility and enzymatic hydrolysis of phytate." PLOS ONE 16, no. 8 (August 13, 2021): e0255787. http://dx.doi.org/10.1371/journal.pone.0255787.

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Phytate is a dominant form of organic phosphorus (P) in the environment. Complexation and precipitation with polyvalent metal ions can stabilize phytate, thereby significantly hinder the hydrolysis by enzymes. Here, we studied the stability and hydrolyzability of environmentally relevant metal phytate complexes (Na, Ca, Mg, Cu, Zn, Al, Fe, Al/Fe, Mn, and Cd) under different pHs, presence of metal chelators, and thermal conditions. Our results show that the order of solubility of metal phytate complexes is as follows: i) for metal species: Na, Ca, Mg > Cu, Zn, Mn, Cd > Al, Fe, ii) under different pHs: pH 5.0 > pH 7.5), and iii) in the presence of chelators: EDTA> citric acid. Phytate-metal complexes are mostly resistant towards acid hydrolysis (except Al-phytate), and dry complexes are generally stable at high pressure and temperature under autoclave conditions (except Ca phytate). Inhibition of metal complex towards enzymatic hydrolysis by Aspergillus niger phytase was variable but found to be highest in Fe phytate complex. Strong chelating agents such as EDTA are insufficient for releasing metals from the complexes unless the reduction of metals (such as Fe) occurs first. The insights gained from this research are expected to contribute to the current understanding of the fate of phytate in the presence of various metals that are commonly present in agricultural soils.

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24

Badirkhan, Z., G. Pastoreb, and O. Akinlade. "Thermodynamics and Structure of Liquid Metals from a New Consistent Optimized Random Phase Approximation." Zeitschrift für Naturforschung A 56, no. 9-10 (October 1, 2001): 605–12. http://dx.doi.org/10.1515/zna-2001-0901.

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Abstract We study thermodynamics and structural properties of several liquid metals to assess the validity of the generalized non-local model potential (GNMP) of Li et al. [J. Phys. F16, 309 (1986)]. By using a new thermodynamically consistent version of the optimized random phase approx imation (ORPA), especially adapted to continuous reference potentials, we improve our previous results obtained within the variational approach based on the Gibbs -Bogoliubov inequality. Hinging on the unified and very accurate evaluation of structure factors and thermodynamic quantities provided by the ORPA, we find that the GNMP yields satisfactory results for the alkali metals. Those for the polyvalent metals, however, point to a substantial inadequacy of the GNMP for high valence systems.

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25

Page, Michael J., and Enrico Di Cera. "Role of Na+and K+in Enzyme Function." Physiological Reviews 86, no. 4 (October 2006): 1049–92. http://dx.doi.org/10.1152/physrev.00008.2006.

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Metal complexation is a key mediator or modifier of enzyme structure and function. In addition to divalent and polyvalent metals, group IA metals Na+and K+play important and specific roles that assist function of biological macromolecules. We examine the diversity of monovalent cation (M+)-activated enzymes by first comparing coordination in small molecules followed by a discussion of theoretical and practical aspects. Select examples of enzymes that utilize M+as a cofactor (type I) or allosteric effector (type II) illustrate the structural basis of activation by Na+and K+, along with unexpected connections with ion transporters. Kinetic expressions are derived for the analysis of type I and type II activation. In conclusion, we address evolutionary implications of Na+binding in the trypsin-like proteases of vertebrate blood coagulation. From this analysis, M+complexation has the potential to be an efficient regulator of enzyme catalysis and stability and offers novel strategies for protein engineering to improve enzyme function.

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26

Niciu, H., Dorel Radu, C. Onose, A. Ioncea, Daniela Niciu, H. Stroescu, and C. S. Onose. "The Permanently Bonded Glass Decor from Chemical Precursors." Advanced Materials Research 39-40 (April 2008): 579–82. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.579.

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Alkaline earth metal silicates as well as many polyvalent metals silicates can be obtained through aqueous solutions reactions between an alkaline silicate solution and the solutions of metal salts. The vitrifiation of the oxide compositions, established by the necessary molar ratios for the projected glass, is realised by calculating the concentration of chemical precursors, through their reaction directly on the substrate. The sodium silicate viscosity in aqueous solution and the viscosity of nitrogenated compounds or oxalates necessary in the silicates synthesis is compatible with the necessary viscosity for ink-jet cartridges. The necessary silicates forming reactions were studied directly on the deposition support, so that the functional characteristics of the multicompartment ink-jet cartridges were used. Compositions were realised, in which the colouring effect was obtained with ionic colorants. The vitrifiation and the quality of the obtained thin films were studied through Optical Microscopy and Scanning Electron Microscopy.

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27

El Mendoub, E. B., R. Albaki, I. Charpentier, J. L. Bretonnet, J. F. Wax, and N. Jakse. "Molecular dynamics and integral equation study of the structure and thermodynamics of polyvalent liquid metals." Journal of Non-Crystalline Solids 353, no. 32-40 (October 2007): 3475–79. http://dx.doi.org/10.1016/j.jnoncrysol.2007.05.099.

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28

Olakanmi, Oyebode, John B. Stokes, Shadab Pathan, and Bradley E. Britigan. "Polyvalent Cationic Metals Induce the Rate of Transferrin-independent Iron Acquisition by HL-60 Cells." Journal of Biological Chemistry 272, no. 5 (January 31, 1997): 2599–606. http://dx.doi.org/10.1074/jbc.272.5.2599.

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29

Beuneu, François, and J. S. Helman. "Spin-orbit relaxation and the Knight shift in small superconducting particles of simple polyvalent metals." Physical Review B 31, no. 5 (March 1, 1985): 2776–78. http://dx.doi.org/10.1103/physrevb.31.2776.

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30

Kajsheva, Nelli Shalikovna, Alexander Shalikovich Kajshev, Anna Borisovna Samoryadova, Sergey Vasilyevich Volokitin, Christina Nicolaevna Gulbjakova, and Ekaterina Alexandrovna Maslovskaya. "The Structure of Insoluble Pectinates and Alginates of Polyvalent Metals Based on IR Spectra Data." American Journal of Analytical Chemistry 08, no. 05 (2017): 334–44. http://dx.doi.org/10.4236/ajac.2017.85025.

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31

Comesse, Sébastien, Ismail Alahyen, Laure Benhamou, Vincent Dalla, and Catherine Taillier. "20 Years of Forging N-Heterocycles from Acrylamides through Domino/Cascade Reactions." Synthesis 53, no. 19 (May 10, 2021): 3409–39. http://dx.doi.org/10.1055/a-1503-7932.

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AbstractAcrylamides are versatile building blocks that are easily obtained from readily available starting materials. During the last 20 years, these valuable substrates bearing a nucleophilic nitrogen atom and an electrophilic double bond have proven to be efficient domino partners, leading to a wide variety of complex aza-heterocycles of synthetic relevance. In this non-exhaustive review, metal-free and metal-triggered reactions followed by an annulation will be presented; these two approaches allow good modulation of the reactivity of the polyvalent acrylamides.1 Introduction2 Metal-Free Annulations2.1 Domino Reactions Triggered by a Michael Addition2.2 Domino Reactions Triggered by an Aza-Michael Addition2.3 Domino Processes Triggered by an Acylation Reaction2.4 Domino Reactions Triggered by a Baylis–Hillman Reaction2.5 Cycloadditions and Domino Reactions2.6 Miscellaneous Domino Reactions3 Metal-Triggered/Mediated Annulations3.1 Zinc-Promoted Transformations3.2 Rhodium-Catalyzed Functionalization/Annulation Cascades3.3 Cobalt-Catalyzed Functionalization/Annulation Cascades3.4 Ruthenium-Catalyzed Functionalization/Annulation Cascades3.5 Iron-Catalyzed Functionalization/Annulation Cascades3.6 Palladium-Catalyzed Functionalization/Annulation Cascades3.7 Copper-Catalyzed Transformations3.8 Transition Metals Acting in Tandem in Domino Processes4 Radical Cascade Reactions5 Conclusion

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32

Bal, Naresh C., Nivedita Jena, Danesh Sopariwala, Tuniki Balaraju, Sana Shaikh, Chandralata Bal, Ashoke Sharon, Sandor Gyorke, and Muthu Periasamy. "Probing cationic selectivity of cardiac calsequestrin and its CPVT mutants." Biochemical Journal 435, no. 2 (March 29, 2011): 391–99. http://dx.doi.org/10.1042/bj20101771.

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CASQ (calsequestrin) is a Ca2+-buffering protein localized in the muscle SR (sarcoplasmic reticulum); however, it is unknown whether Ca2+ binding to CASQ2 is due to its location inside the SR rich in Ca2+ or due to its preference for Ca2+ over other ions. Therefore a major aim of the present study was to determine how CASQ2 selects Ca2+ over other metal ions by studying monomer folding and subsequent aggregation upon exposure to alkali (monovalent), alkaline earth (divalent) and transition (polyvalent) metals. We additionally investigated how CPVT (catecholaminergic polymorphic ventricular tachycardia) mutations affect CASQ2 structure and its molecular behaviour when exposed to different metal ions. Our results show that alkali and alkaline earth metals can initiate similar molecular compaction (folding), but only Ca2+ can promote CASQ2 to aggregate, suggesting that CASQ2 has a preferential binding to Ca2+ over all other metals. We additionally found that transition metals (having higher co-ordinated bonding ability than Ca2+) can also initiate folding and promote aggregation of CASQ2. These studies led us to suggest that folding and formation of higher-order structures depends on cationic properties such as co-ordinate bonding ability and ionic radius. Among the CPVT mutants studied, the L167H mutation disrupts the Ca2+-dependent folding and, when folding is achieved by Mn2+, L167H can undergo aggregation in a Ca2+-dependent manner. Interestingly, domain III mutants (D307H and P308L) lost their selectivity to Ca2+ and could be aggregated in the presence of Mg2+. In conclusion, these studies suggest that CPVT mutations modify CASQ2 behaviour, including folding, aggregation/polymerization and selectivity towards Ca2+.

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33

Zverev, A. V., S. S. Khvoshchev, and V. Ya Mironovich. "Heats of adsorption of CO2 and NH3 on L-type zeolites with cations of polyvalent metals." Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 37, no. 3 (March 1988): 417–19. http://dx.doi.org/10.1007/bf00965344.

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34

Belenkii, A. Ya. "On the atomic size effects in alloys of noble and transition metals with polyvalent metals and metalloids and their glass forming ability." Scripta Metallurgica et Materialia 25, no. 8 (August 1991): 1939–43. http://dx.doi.org/10.1016/0956-716x(91)90332-u.

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35

Li, Lingli, Ming Yu, Chao Yang, Chunping Deng, Lili Ma, and Yucheng Liu. "Effects of abiotic factors on the stability and infectivity of polyvalent coliphage." Water Science and Technology 85, no. 1 (November 24, 2021): 141–51. http://dx.doi.org/10.2166/wst.2021.505.

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Abstract Bacteriophage has attracted growing interest as a promising therapeutic agent for pathogenic bacteria, especially for antibiotic-resistant bacteria. However, the various abiotic conditions could impact the stability of phages and further threat host–virus interactions. Here, we investigated the stability and lytic activity of virulent polyvalent coliphage (named PE1) by double-layer plaque assay. PE1 can efficiently infect both the drug-sensitive Escherichia coli K12 and multidrug-resistant E. coli NDM-1 even after prolonged storage at 4 °C for up to two months. Results showed that PE1 exhibits an outstanding stability to infect E. coli strains under a wide range of thermal (4 °C–60 °C) and pH (4–11) conditions, which covers the thermal and pH variations of most wastewater treatment plants. Moreover, PE1 exhibited high resistibility to heavy metals exposure including Cu2+, Cd2+, Co2+, and Cr3+ at the concentrations below 0.5 mM, and an excellent resistant ability to the variation of ionic strength, which still retained strong infectious ability even treated with saturated sodium chloride solution (350 g/L). This work shows that polyvalent phage PE1 has a strong adaptive capacity to various abiotic factors and should be a good candidate of being an antibacterial agent, especially for antibiotic-resistant bacteria control in sewage.

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36

Igwe, Charles A., and Karl Stahr. "Water-stable aggregates of flooded Inceptisols from south-eastern Nigeria in relation to mineralogy and chemical properties." Soil Research 42, no. 2 (2004): 171. http://dx.doi.org/10.1071/sr03041.

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Information on the influence of chemical and mineralogical properties on soil aggregate stability of field soils subjected to waterlogging at some time of the year is essential for better management of these soils. We studied water-stable aggregates (WSA) of various sizes for clay flocculation index, soil organic carbon, total elements, and mineralogy of the soil, and related these properties to aggregate stability. Five soil profiles sited on the floodplain of the River Niger were studied. The topsoils were dominated in all profiles except near the river by WSA�>�2.00�mm. Also the mean-weight diameter (MWD) of the topsoil followed the trend in WSA > 2.00 mm. Thixotropic age hardening appeared to be responsible for the rather high values of WSA > 2.00 and MWD in the topsoil. Soil organic carbon content associated significantly better with macroaggregates than microaggregates. The aggregating effects of the polyvalent cations manifested more on the microaggregates. The stabilising role of various forms of Fe, Al, and Mn oxides is believed to be as result of their large surface area, abundance, and the favourable environment for their formation. These polyvalent metals may have formed bridges between clay and organic matter in the formation of aggregates.

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37

Manh, D. Nguyen, D. Mayou, A. Pasturel, and F. Cyrot-Lackmann. "Electronic structure and hybridisation effects in transition-metal-polyvalent-metal alloys." Journal of Physics F: Metal Physics 15, no. 9 (September 1985): 1911–27. http://dx.doi.org/10.1088/0305-4608/15/9/010.

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38

Petrenko, Olga, Ruslan Lavrik, Kateryna Terebilenko, Volodymir Trachevsky, and Valentyna Galimova. "Influence of fluorides on phase relations in the molten systems MI2O-Р2О5 Mn2O3/MIIO, МI – Li, Na, K; MII – Ni, Co." French-Ukrainian Journal of Chemistry 7, no. 2 (2019): 104–10. http://dx.doi.org/10.17721/fujcv7i2p104-110.

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Addition of alkaline fluorides to molten phosphates with a composition MI2O-Р2О5-Mn2O3 and MI2O-Р2О5-MIIO (МI – Li, Na, K) gradually changes the solubility of polyvalent metals oxides and shifts the crystallization areas in the corresponding melts. The results obtained are based on solubility curves found for Mn2O3, СоО and NiO in the fluxes of MI2O-Р2О5 -MF and MI2O-Р2О5 -MF (where МI – Li, Na, K) and X-Ray diffraction, IR spectroscopy and thermal analysis. The presence of 10 and 20 % mass of fluorides provides molten polyphosphates depolymerization and yields pyro- Li2MnP2O7, K2CoP2O7, Na2CoP2O7and orthophosphates Na2Mn3(P2O7)2, NaMnPO4, NaNiPO4 single crystals growth.

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39

Juárez-Rebollar, Daniel, Camilo Rios, Concepción Nava-Ruíz, and Marisela Méndez-Armenta. "Metallothionein in Brain Disorders." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/5828056.

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Metallothioneins are a family of proteins which are able to bind metals intracellularly, so their main function is to regulate the cellular metabolism of essential metals. There are 4 major isoforms of MTs (I–IV), three of which have been localized in the central nervous system. MT-I and MT-II have been localized in the spinal cord and brain, mainly in astrocytes, whereas MT-III has been found mainly in neurons. MT-I and MT-II have been considered polyvalent proteins whose main function is to maintain cellular homeostasis of essential metals such as zinc and copper, but other functions have also been considered: detoxification of heavy metals, regulation of gene expression, processes of inflammation, and protection against free radicals generated by oxidative stress. On the other hand, the MT-III has been related in events of pathogenesis of neurodegenerative diseases such as Parkinson and Alzheimer. Likewise, the participation of MTs in other neurological disorders has also been reported. This review shows recent evidence about the role of MT in the central nervous system and its possible role in neurodegenerative diseases as well as in brain disorders.

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Moss, Darren M., Marco Siccardi, Matthew Murphy, Michael M. Piperakis, Saye H. Khoo, David J. Back, and Andrew Owen. "Divalent Metals and pH Alter Raltegravir DispositionIn Vitro." Antimicrobial Agents and Chemotherapy 56, no. 6 (March 26, 2012): 3020–26. http://dx.doi.org/10.1128/aac.06407-11.

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ABSTRACTRaltegravir shows marked pharmacokinetic variability in patients, with gastrointestinal pH and divalent-metal binding being potential factors. We investigated raltegravir solubility, lipophilicity, pKa, and permeativityin vitroto elucidate known interactions with omeprazole, antacids, and food, all of which increase gastric pH. Solubility of raltegravir was determined at pH 1 to 8. Lipophilicity of raltegravir was determined using octanol-water partition. Raltegravir pKawas determined using UV spectroscopy. The effects of pH, metal salts, and omeprazole on the cellular permeativity of raltegravir were determined using Caco-2 monolayers. Cellular accumulation studies were used to determine the effect of interplay between pH and ABCB1 transport on raltegravir accumulation. Samples were analyzed using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) or scintillation counting. Raltegravir at 10 mM was partly insoluble at pH 6.6 and below. Raltegravir lipophilicity was pH dependent and was reduced as pH was increased from 5 to 9. The pKaof raltegravir was 6.7. Raltegravir cellular permeativity was heavily influenced by changes in extracellular pH, where apical-to-basolateral permeativity was reduced 9-fold (P< 0.05) when apical pH was increased from 5 to 8.5. Raltegravir cellular permeativity was also reduced in the presence of magnesium and calcium. Omeprazole did not alter raltegravir cellular permeativity. Cellular accumulation of raltegravir was increased independently by inhibiting ABCB1 and by lowering extracellular pH from pH 8 to 5. Gastrointestinal pH and polyvalent metals can potentially alter the pharmacokinetic properties of raltegravir, and these data provide an explanation for the variability in raltegravir exposure in patients. The evaluation of how divalent-metal-containing products, such as multivitamins, that do not affect gastric pH alter raltegravir pharmacokinetics in patients is now justified.

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Hsu, Liang-Ching, Yu-Ting Liu, Chien-Hui Syu, Mei-Hsia Huang, Yu-Min Tzou, and Heng Yi Teah. "Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu 2+ , Zn 2+ and Al 3+ ) addition in various molar ratios." Royal Society Open Science 5, no. 3 (March 2018): 171941. http://dx.doi.org/10.1098/rsos.171941.

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Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu 2+ , Zn 2+ and Al 3+ . The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu 2+ shifted from phenolic diketone groups at Cu/TC molar ratio < 1 to amide groups at Cu/TC molar ratio ≥ 1. For the addition of Al 3+ , the complexation only took place with phenolic diketone groups, resulting in the enhanced TC adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al 3+ led to the competitive adsorption with Al/TC complexes. For the Zn 2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios.

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42

Liu, Jian Guo, Chang Zhen Chen, and Jing Liu. "A Novel Dialysis Process to Isolate Phosvitin from Hen Egg Yolk." Advanced Materials Research 554-556 (July 2012): 1542–46. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.1542.

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The objective of this work is to develop a novel dialysis process for the isolation of phosvitin from hen egg yolk avoiding the use of organic solvents and polyvalent metals. This bioseparation process consists of NaCl precipitation, heat treatment and dialysis, which was proposed on the basis of the property difference (especially solubility and thermostability) among yolk proteins. The native molecular mass of the purified phosvitin estimated by fast protein liquid chromatography on a Superdex 75 column was about 165 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed two bands around 35 kDa. The nitrogen to phosphorus atomic ratio of the purified phosvitin was 2.8 ± 0.2, with a yield of 87.1%. The phosvitin product had α-helix of 36%, β-sheet of 28% and random coil of 36% at pH 7.0, consistent with the literature values. This shows that the purified phosvitin folded with a reasonable secondary structure.

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Addy, M., and J. Moran. "Mechanisms of Stain Formation on Teeth, in Particular Associated with Metal Ions and Antiseptics." Advances in Dental Research 9, no. 4 (December 1995): 450–56. http://dx.doi.org/10.1177/08959374950090041601.

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Much has been written on the subject of extrinsic tooth discoloration, but, except when the pigment is intentionally applied, the etiologies and mechanisms are poorly understood. Extrinsic stains have been classified as non-metallic or metallic. The pigment usually lies not on or in the dental tissues, but in surface deposits, particularly the acquired pellicle layer and at sites receiving limited cleaning. Whether pigments absorb, adsorb, or chemically interact with dental surfaces is unclear. Some stains merely seem to reflect the color of the apparent source, whereas others have been ascribed to a secondary chemical alteration of a substance at the tooth or pellicle surface. Theories of chromogenic bacteria and formation of metal sulfides are frequently propounded but without clear supportive evidence. Staining by cationic antiseptics and, to a lesser extent, metal salts has attracted research interest. Chlorhexidine and other cationic antiseptics, it is hypothesized, may catalyze browning reactions or facilitate metal sulfide formation in pellicle. Controlled clinical studies have repeatedly shown that dental and mucosal staining associated with the use of chlorhexidine and some metal salts is dependent upon volunteers' imbibing reasonable quantities of chromogenic beverages, such as tea. However, it must be appreciated that cationic antiseptics and polyvalent metals can precipitate chromogenic material from a large range of dietary compounds. The control of dental staining, at least that associated with chlorhexidine, can be achieved both in vitro and in vivo by the use of oxidizing agents which appear to remove the stain physically from the surfaces.

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Kerisit, Sebastien, Eric J. Bylaska, Michael S. Massey, Martin E. McBriarty, and Eugene S. Ilton. "Ab Initio Molecular Dynamics of Uranium Incorporated in Goethite (α-FeOOH): Interpretation of X-ray Absorption Spectroscopy of Trace Polyvalent Metals." Inorganic Chemistry 55, no. 22 (November 3, 2016): 11736–46. http://dx.doi.org/10.1021/acs.inorgchem.6b01773.

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Terzieff, Peter. "The viscosity of liquid alloys of polyvalent metals with Cu, Ag and Au: Theoretical treatments based on the enthalpy of mixing." Physica B: Condensed Matter 404, no. 14-15 (July 2009): 2039–44. http://dx.doi.org/10.1016/j.physb.2009.03.034.

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46

Ershov, Boris G., and Bladimir P. Shilov. "Reactions of ozone and intermediate products of its decomposition with actinides, lanthanides and transition metals in aqueous solutions." Radiochimica Acta 109, no. 8 (June 8, 2021): 583–601. http://dx.doi.org/10.1515/ract-2021-1007.

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Abstract The properties and stability of ozone in aqueous solutions of various compositions in the рН range of 0–14 were considered. The effect of anions and cations, which are involved in the redox reactions of actinides, on the stability of ozone and its reactivity has been studied. The reactions of О3 with ions of d- and f-elements were analyzed. Depending on the solution composition and рН value, the reaction can occur directly with the O3 molecule (direct mechanism) and/or with short-lived ion-radical products (•OH, HO 2 • / O 2 − • ${\text{HO}}_{2}^{{\bullet}}/{\text{O}}_{2}^{-{\bullet}}$ , H2O2/ HO 2 − ${\text{HO}}_{2}^{-}$ , O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ ) formed upon ozone decomposition in water (indirect mechanism). Ions with inert coordination sphere react with О3 in the outer-sphere fashion with electron transfer. Polyvalent ions with labile coordination spheres are oxidized in acidic medium via О atom transfer, possibly, with intermediate peroxy addition (H2O2, HNO4, H2SO5, etc.). In alkaline medium, О3 is converted to the O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ radical ion, which is the key oxidant for actinides. The results of studies and the mechanisms of reactions of ozone and its intermediates decomposition products with U, Np, Pu, and Am in various oxidation states and with some transition metals (Fe, Mn, Ag, Co, etc.) in aqueous solutions are presented and discussed.

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47

Shrestha, Pratiksha, Krishna Prasad Rai, and Anil Kumar Anal. "Interactions of Bio-macromolecules During Processing of Instant Asian Noodles: A Review." Journal of Food Science and Technology Nepal 9 (December 19, 2016): 1–10. http://dx.doi.org/10.3126/jfstn.v9i0.16197.

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The review focuses on how the protein, fats, carbohydrates and water interact and form the complexes during different stages of processing of instant noodles. Moisture is needed for dough formation and chemical interactions therein. Appropriate moisture content is required for proper gelatinization of noodle strand during steaming and eventually moisture is evaporatedoff by drying and frying to increase its shelf life. Frying oil may undergo degradation process invited by high frying time and temperature, high moisture in oil and polyvalent metals. Various intermediate products like dimers and polymers accelerate the oil degradation finally changing the physiochemical properties of oil rendering it unacceptable for processing. Gliadinand glutenin gives noodle its viscoelastic character. The polymeric glutenin network develops throughout the process of mixing, resting and subsequent stages of sheeting. Protein content and amylose content in noodle are inversely proportional to the oil uptake ratio. Another possibility is the non-enzymatic browning reaction during frying of instant noodles.

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Gupta, Himadri S., Peter Fratzl, Michael Kerschnitzki, Gunthard Benecke, Wolfgang Wagermaier, and Helmut O. K. Kirchner. "Evidence for an elementary process in bone plasticity with an activation enthalpy of 1 eV." Journal of The Royal Society Interface 4, no. 13 (November 7, 2006): 277–82. http://dx.doi.org/10.1098/rsif.2006.0172.

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The molecular mechanisms for plastic deformation of bone tissue are not well understood. We analysed temperature and strain-rate dependence of the tensile deformation behaviour in fibrolamellar bone, using a technique originally developed for studying plastic deformation in metals. We show that, beyond the elastic regime, bone is highly strain-rate sensitive, with an activation volume of ca 0.6 nm 3 . We find an activation energy of 1.1 eV associated with the basic step involved in the plastic deformation of bone at the molecular level. This is much higher than the energy of hydrogen bonds, but it is lower than the energy required for breaking covalent bonds inside the collagen fibrils. Based on the magnitude of these quantities, we speculate that disruption of electrostatic bonds between polyelectrolyte molecules in the extrafibrillar matrix of bone, perhaps mediated by polyvalent ions such as calcium, may be the rate-limiting elementary step in bone plasticity.

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Barot, Nishant, Prashant K. Mehta, Ashok Rao, Riya Thomas, and Yung-Kang Kuo. "Effects of iso- and polyvalent substitutions on the short/long-range crystalline order in CuCrO2 compounds." Journal of Alloys and Compounds 791 (June 2019): 134–43. http://dx.doi.org/10.1016/j.jallcom.2019.03.291.

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Strelko, V. V. "New sol–gel processes in the synthesis of inorganic sorbents and ion exchangers based on nanoporous oxides and phosphates of polyvalent metals." Journal of Sol-Gel Science and Technology 68, no. 3 (March 5, 2013): 438–46. http://dx.doi.org/10.1007/s10971-013-2990-0.

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