Mixture Of Zinc Research Articles

Asymmetric Synthesis of α-Amino-β-hydroxy Acids Using a Chiral Pyridoxal-Like Pyridinophane–Zinc Complex as an Enzyme Mimic; Scope and Limitation

Abstract A chelate complex (4) with high homogeneity was precipitated upon stirring a mixture of zinc(II) ion and a Schiff base produced from glycine and (R)- or (S)-15-formyl-14-hydroxy-2,8-dithia[9](2,5)pyridinophane, chiral pyridoxal-like pyridinophane. A four-coordinated zinc chelate complex was newly proposed as the structure of 4. Aldol condensations between 4 and several aldehydes were attempted at pH 10.0. Only small linear chain aldehydes, such as acetaldehyde and propionaldehyde, could react with 4 under these conditions to give the corresponding α-amino-β-hydroxy acid in the range of 27–77% enantiomeric excess.

On the thermal degradation of poly(vinyl chloride). Synergistic effect of mixtures of lead and zinc carboxylates

AbstractThe effect of a mixture of lead and zinc carboxylates on the thermal decomposition of poly(vinyl chloride) in air is studied. The results obtained by weight loss determination and IR and UV spectroscopic analysis showed a marked influence of these compounds on the degradation of PVC. The greatest stabilization was achieved with lead dodecanoate. With a mixture of lead octadecanoate and zinc octadecanoate an indication of synergism was observed leading to enhanced stabilization. With the mixture of lead and zinc dodecanoate the level of stabilization was less; this mixture catalysed the degradation of PVC at 473 K. The mechanism of the stabilization of PVC by the studied compounds is discussed.

Thermal dehydrochlorination and stabilization of poly(vinyl chloride) in solution: Part III—Zn-Ca stearates as stabilizers

The thermal degradation of poly(vinyl chloride) (PVC) in trichlorobenzene (TCB) solution at 187°C has been studied in the presence of various mixtures of zinc and calcium stearates, using coulometric titration of chloride ions, HCl evolution measurements and spectroscopic analysis (FTIR and UV) of the degraded polymer at various times. The substitution reaction, initially suggested by Frye and Horst 1,2 is clearly demonstrated, although the very small amount of stearate groups involved with respect to the number of vinyl chloride units makes it difficult and requires the use of high performance equipment and careful recording conditions. Many of the known features of the stabilization of PVC with mixed metal soaps are also observed. In addition, a transient complex between the metal stearates is observed which cannot be separated from the polymer because it shows the same solubility behavior. Evidence for secondary reactions between metal chlorides and stearic acid is given. Finally, the rates of the processes are very dependent on the amounts of structural defects in the initial polymer.

Zinc(II) complexes of 4,7-diazadecane-1,10-diamine, 4,8-diazaundecane-1,11-diamine, and tetraethylenepentamine: a carbon-13 nuclear magnetic resonance study

Carbon- 13 n.m.r. spectra are reported as a function of pH for mixtures of zinc and 4,7-diazadecane-1,10 diamine (dad), 4,8-diazaundecane-1,11-diamine (daud), or tetraethylenepentamine (tetren), of zinc and dadd or daud with 1,2-diaminoethane (en), 1,3-diamionpropane (pn), or glycine (gly), and of zinc and tetren with en or pn; supporting data have also been obtained from potentiometric titrations. The pH profiles have been analysed and chemical shifts determined for the following species: [Zn(dadd)]2+, [Zn(dadd)(en)]2+, [Zn(dadd)(glyO)]+, [Zn(daud)]2+, [Zn(daud)(OH)]+, [Zn(daud)(en)]2+, [Zn(daud)(pn)]2+, [Zn(daud)(glyO)]+, and [Zn(tetren)]2+. Stability constants have been determined for the ternary complexes. The results support the proposals that [Zn(dadd)]2+ and [Zn(daud)]2+ contain ionizable water but [Zn(tetren)]2+ does not.

Petrochemical-related DNA damage in wild rodents detected by flow cytometry.

The need for quick, reliable, in situ tests of environmental mutagenicity is evidenced by increasing public concern about potential health effects of pollutants. Conventional tests of clastogenicity usually involve treatment of laboratory test systems with pure samples of suspect compounds followed by scoring numerous metaphase cells for chromosome aberrations. There are at least two shortcomings of these test protocols. They are very time consumptive and are generally restricted to controlled laboratory situations which may not realistically indicate the effects of environmental pollution. The use of flow cytometry to study resident rodent species as bioindicators provides a system by which cytogenetic effects of environmental pollutants upon exposed organisms rapidly and accurately can be ascertained. The authors found that two species of wild rodents (Peromyscus leucopus and Sigmodon hispidus) living at a dump site polluted with a complex mixture of oil, grease, polychlorinated biphenols, hexachlorobenzene, zinc, manganese, cadmium, chromium, copper, and lead had significantly higher frequencies of chromosomal aberrations than did animals from two unpolluted control sites. These data suggest that resident small mammals may be useful as in situ monitors of the presence and action of mutagenic pollutants in the environment. This study was conducted to determine if changes in patternsmore » of DNA content indicative of the action of mutagens could be detected by flow cytometric analysis of tissues from these same animals.« less

Formation and Structure of Spinel Solid Solution in Li<sub>2</sub>O-MO-GeO<sub>2</sub> (M=Zn, Co, Ni) System

The formation and structure of spinel solid solutions were studied in the system Li2O-MO-GeO2 (M=Zn, Go, Ni). Specimens were prepared by calcining mixtures of zinc, cobalt and germanium oxides, lithium and nickel carbonates at 950°C for 16h, and were analyzed by X-ray powder diffraction diagrams and visible reflectance spectra. The crystal structure of Li2O⋅MO⋅3GeO2 (M=Zn, Go, Ni) was refined by the pattern fitting method for X-ray powder diffraction.(1) Spinel solid solutions with superstructure are obtained over the whole region of Li2O-(1-x-y)ZnO-xCoO-yNiO-3GeO2 system.(2) The structure of Li2O⋅MO⋅3GeO2 (M=Zn, Co, Ni) is cubic, with the space group P4332 and Z=4. These compounds have the cell dimensions: a=8.193A (M=Zn), 8.204A (M=Co), 8.181A (M=Ni). The cation distribution of Li2O⋅MO⋅3GeO2 (M=Zn, Co) is nearly Li0.5M0.5 [Li0.5Ge1.5] O4, while that of Li2O⋅NiO⋅3GeO2 is nearly Li [Ni0.5Ge1.5] O4. The octahedral site cations have 1:3 order. As Ni2+ content increases, Ni2+ ions occupy octahedral sites and Li+ ions migrate from octahedral to tetrahedral sites. The intensities of superlattice lines decrease because of decrease in the difference of atomic scattering factor between octahedral site cation. The sizes of two kinds of octahedra depend on the ionic radii of central cation.(3) Reflectance spectra show the typical absorption of 4-coordinated Co2+ ion and 6-coordinated Ni2+ ion.

Selective and precise photometric titration of metal ions with EDTA using masking agents. Part III. Determination of calcium, lead and zinc in mixtures using simple inorganic ions as masks

Individual photometric titrations of calcium, lead and zinc (0.01 M solutions) were carried out in the presence of copper, nickel, cobalt, zinc, cadmium, mercury, silver aluminium and tin using a variety of simple inorganic anions as masking agents. Good photometric and linear extrapolation end-points yielding relative standard deviations of 0.06% were achieved in many instances.

Simultaneous determination of metals in two-component mixtures with 5-sulfo-8-quinolinol by using phase-resolved fluorimetry

Determinations of metals in two-component mixtures are described in which 5-sulfo-8-quinolinol is used to produce fluorescent chelates of the metals. The metal chelates have broad, overlapping fluorescence spectra but the fluorescence lifetimes (τ) of the chelates are sufficiently different to permit phase-resolved fluorimetric determinations in which the fluorescence contributions of the two chelates can be resolved. Average determination errors ranged from −4.1% to 2.1% for each metal chelate in mixtures of zinc and cadmium (Δτ = 1.0 ns), gallium and indium (Δτ = 1.7 ns) and aluminum and gallium (Δτ = 5.3 ns). Limits of detection and determination for each individual metal chelate were found to be three times and five times greater, respectively, for the phase-resolved measurements relative to steady-state measurements under the same experimental conditions. Effects of pH on the fluorescence lifetimes and intesities of the metal chelates were studied.

Apple, Mite Control, 1985

Abstract Test chemicals were applied to 8- to 20-year-old apple trees at Monmouth, Maine, as dilute sprays using a hand gun and a hydraulic sprayer operating at 250 psi and at 300 (Test 3) to 350 gal/acre. Spray dates were 30 Apr (half-inch green, HIG), 11 May (tight cluster, TC), 16 May (pink, P), 24 May (bloom, B), 28-29 May (petal fall, PF), 7 Jun (first cover, IC), and 17 Jul and 25 Jul. The standard pesticide program consisted of Difolatan 4F (5 qt/100) on 24 Apr, Captan 80W (1 lb) on 5 dates, Cyprex 65W (0.8 lb) on 1 date, Imidan 50W (1.1 lb) on 1 date, Sevin 80W (1.25 lb) on 4 dates, and on 4 Jun there was a mixture of epsom salts (15 lb), Solubor 20W (1 lb), zinc chelate (1 lb) and Manzate 200 80W (1 lb). There were no mixtures of acaricides with other pesticides. There were 4 single-tree replications for each treatment. A randomized complete block design was used, with 3 ‘Red Delicious’ and 1 ‘Cortland’ cultivar in Test 1 and 2 ‘Red Delicious’ and 2 ‘Cortland’ cultivars in Tests 2 and 3. From each tree 25 leaves were collected at chest-height around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20 and alcohol mixture; mites were counted the same day. May and Jun were cool, the first half of Jul was wet (3.9 inches rain), and Aug was wetter (3.4 inches rain) and cooler than normal.

The toxicity to Clarias Lazera of copper and zinc applied jointly

1. The acute toxicity to juvenile Clarias lazera of a mixture of copper and zinc over a 96 hr exposure period was determined. Fish were exposed to the summation of half the 96 hr tlm value of each toxicant. 2. Percentage survival was much reduced indicating that the metals potentiate each others lethal action. 3. Comparison between metal residues in fish exposed to copper and zinc or to their mixture showed that the uptake of one metal was decreased by the presence of the other. 4. Toxic effects of the mixture on the physiological parameters studied were mainly attributable to copper, indicating that the presence of zinc did not influence the mode of action of copper.

Carbon-13 nuclear magnetic resonance study of the zinc(II) complexes of 3,7-diazanonane-1,9-diamine and 1,2-diaminoethane

Carbon-13 n.m.r. spectra are reported as a function of pH for 3,7-diazanonane-1,9-diamine (dadn), for mixtures of dadn or 1,2-diaminoethane (en) and zinc nitrate, and for mixtures of zinc and dadn with en, 1,3-diaminopropane (pn), acetate, glycine (gly), and L-alanine (ala). The pH profiles have been analysed by computer and invidual chemical shifts determined for the following species: dadn, Hdadn+, H2dadn2+, H3dadn3+, H4dadn4+, [Zn(dadn)]2+, [Zn(dadn)(OH)]+, [Zn(dadn)(en)]2+, [Zn(dadn)(pn)]2+, [Zn(dadn)(MeCO2)]+, [Zn(dadn)(glyO)]+, [Zn(dadn)(alaO)]+, [Zn(dadn)(Hpn)]3+, [{Zn(dadn)}2(pn)]4+, [Zn(dadn)(gly)]2+, [zn(dadn)(glyO)2], [Zn(dadn)(ala)]2+, [Zn(en)]2+, [Zn(en)2]2+, and [Zn(en)3]2+. Acid dissociation constants have also been determined for the protonated dadn species and stability constants for the ternary and en complexes. Proposals are made concerning the co-ordination geometries of zinc–dadn complexes and possible generalisations are considered.

Survival and hepatic metallothionein in developing rainbow trout exposed to a mixture of zinc, copper, and cadmium.

Rainbow trout (Salmo gairdneri) in Buttle Lake on Vancouver Island, B.C. are exposed to metal contamination originating from a copper and zinc mining operation at Myra Falls near the head of the lake. In order to properly assess the risk to a population of rainbow trout in Buttle Lake, the authors initiated a long-term exposure of rainbow trout from hatch including the swim-up stage. Copper, zinc or cadmium are known to induce metallothionein in mammals and as a mixture of metals, induce hepatic metallothionein in rainbow trout. Investigation of hepatic metallothionein concentrations in wild rainbow trout from Buttle Lake and in lakes of the Campbell River downstream showed a correlation with metal concentrations in the water. Rainbow trout held in situ for 4 weeks showed the same correlation. In this report they determined whether or not the degree of contamination was correlated with concentrations of metallothionein in the livers of rainbow trout exposed to the mixture of metals during the early life stages.

Determination of no effect levels of heavy metals for rainbow trout using hepatic metallothionein

Rainbow trout ( Salmo gairdneri) were exposed to various sublethal concentrations of a mixture of zinc, copper and cadmium for periods of time ranging from 4 to 16 weeks and the concentration of metallothionein (MT) in the livers was determined. The data were described by linear regressions of hepatic MT (with 95% confidence limits) against concentration of metal. From these data could be determined a “no observable effect” concentration for each metal at which the concentration of hepatic MT in exposed fish was not distinguishable from that in unexposed fish. The value thus determined was in close agreement with estimates of the “no observable effect” concentrations of zinc, copper and cadmium calculated for soft water by other authors. The elevation of hepatic MT in rainbow trout therefore appears to provide a useful biological response for the estimation of “no observable effects” of zinc, copper and cadmium in mixture in the natural environment.

ChemInform Abstract: CHEMISTRY OF THE PODOCARPACEAE. LXVI. PREPARATION AND REACTIONS OF DIMETHYL 13,14,15,16-TETRANORLABD-8(17)-ENE-12,19-DIOATE

Im Gegensatz zu früheren Versuchen läßt sich der ungesättigte Ester (Ib) leicht aus dem Keton (Ia) erhalten - Nebenprodukt ist das Lacton (III).

Effect of Several Dermatitis Preventing Agents on Foot Pad Dermatitis in Dwarf and Normal Sized Single Comb White Leghorn Layers

Studies were conducted to determine the effects of increased dietary levels of vitamin and trace mineral mixtures, methionine, meat and bone meal, fish meal, and safflower oil on foot pad dermatitis in dwarf and normal size Single Comb White Leghorn layers. All layers were maintained in individual wire cages throughout a 40-week experiment period. Individual birds were scored for the incidence of foot pad dermatitis and production parameters were recorded. No significant decrease in the incidence of dermatitis was observed from the following dietary supplements: a 50% increase in a vitamin or a complete trace mineral mixture; a 50% increase in an iron, copper, iodine, and cobalt or a manganese and zinc mixture; .05% methionine; 5% meat and bone meal; 3% herring fish meal; or 2% safflower oil. It was concluded that these mixtures or supplements containing such dermatitis preventative agents as pantothenic acid, zinc, and linoleic acid appeared without effect in minimizing expression of the condition in dwarfs.

Chemistry of the Podocarpaceae. LXVI. Preparation and reactions of dimethyl 13,14,15,16-Tetranorlabd-8(17)-ene-12,19-dioate

The unsaturated diester (3) is conveniently prepared from the keto diester (2) by using a mixture of zinc, dibromomethane and titanium tetrachloride. Its synthetic utility and that of derived products has been explored.

Regulation of calcium, cobalt and zinc by Tetrahymena elliotti

1. 1. Various aspects of the uptake of calcium, zinc and cobalt by Tetrahymena were investigated. 45Ca content of cells varied throughout the cultural cycle, being low in log phase and higher, probably due to calcium granule formation, during lag phase and cultural senescence. 2. 2. Internal calcium content rose with increasing external concentration; at Ca 0 = 20 mM, Ca 1 was about 200 mM and remained high throughout the cultural cycle. The presence of zinc reduced calcium uptake. 3. 3. Zinc uptake was similar to calcium uptake and was accelerated by high calcium concentrations. Zinc was incorporated into intracellular granules with calcium and phosphorus. Calcium may aid the uptake of zinc through driving the synthesis of granules. 4. 4. Cobalt uptake was proportional to external concentration but it was not detected in granules. Cobalt levels may be regulated by outward transport. In mixtures of cobalt and zinc, cobalt entered the cell preferentially. 5. 5. Although volutin granules have a detoxification function, other detoxification mechanisms exist.

Hepatic metallothionein production and resistance to heavy metals by rainbow trout ( Salmo gairdneri)—II. Held in a series of contaminated lakes

1. 1. Rainbow trout held in net pens for 4 weeks in three locations contaminated by heavy metals developed elevated levels of hepatic metallothionein but no acclimation to a combination of zinc, copper and cadmium. 2. 2. Toxicity of the mixture of zinc, copper and cadmium in a ratio of 400:20:1 increased with temperature in the range of 6–21°C. 3. 3. Hepatic metallothionein concentrations after 4 weeks of exposure in situ was correlated with the degree of contamination as measured by zinc concentrations ( P < 0.01).

Hepatic metallothionein production and resistance to heavy metals by rainbow trout ( Salmo gairdneri)—I. Exposed to an artificial mixture of zinc, copper and cadmium

1. 1. Rainbow trout developed elevated hepatic metallothionein concentrations after 4 weeks in a solution containing zinc, copper and cadmium in a fixed ratio of 400:20:1. 2. 2. Resistance to a combination of these metals increased in proportion to the concentration to which they were exposed for 4 weeks. 3. 3. The concentration of copper but not zinc or cadmium in the low molecular weight proteins separated by gel filtration was related to the concentrations of metallothionein present. 4. 4. The combined toxicity of the metals in the mixture was additive.

A comparison of the phytotoxic effects of mancozeb (coordination compound) with mixtures of maneb and zinc

A comparison of the phytotoxic effects of mancozeb (coordination compound) with mixtures of maneb and zinc