EFFECTS OF DIETARY COPPER, ZINC, LEAD, CADMIUM, AND ARSENIC ON GROWTH AND SURVIVAL OF JUVENILE FISH USING LIVE FOOD ORGANISMS

EPA Science Inventory

Except for certain organometallic compounds, dietary exposures of aquatic organisms to metal/metalloids have received little regulatory attention. However, various studies have suggested that dietary exposure could be important, especially in areas where current water column conc...

Zinc-Catalyzed Synthesis of Conjugated Dienoates through Unusual Cross-Couplings of Zinc Carbenes with Diazo Compounds.

PubMed

Mata, Sergio; González, María J; González, Jesús; López, Luis A; Vicente, Rubén

2017-01-23

Zinc-catalyzed selective cross-coupling of two carbene sources, such as vinyl diazo compounds and enynones, enabled the synthesis of conjugated dienoate derivatives. This reaction involved the unprecedented coupling of a zinc furyl carbene with vinyl diazo compounds through the γ-carbon. Alternatively, dienoates were also prepared by a commutative cross-coupling of zinc vinyl carbenes generated from cyclopropenes and simple diazo compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elementary sulfur in effluent from denitrifying sulfide removal process as adsorbent for zinc(II).

PubMed

Chen, Chuan; Zhou, Xu; Wang, Aijie; Wu, Dong-hai; Liu, Li-hong; Ren, Nanqi; Lee, Duu-Jong

2012-10-01

The denitrifying sulfide removal (DSR) process can simultaneously convert sulfide, nitrate and organic compounds into elementary sulfur (S(0)), di-nitrogen gas and carbon dioxide, respectively. However, the S(0) formed in the DSR process are micro-sized colloids with negatively charged surface, making isolation of S(0) colloids from other biological cells and metabolites difficult. This study proposed the use of S(0) in DSR effluent as a novel adsorbent for zinc removal from wastewaters. Batch and continuous tests were conducted for efficient zinc removal with S(0)-containing DSR effluent. At pH<7.5, removal rates of zinc(II) were increased with increasing pH. The formed S(0) colloids carried negative charge onto which zinc(II) ions could be adsorbed via electrostatic interactions. The zinc(II) adsorbed S(0) colloids further enhanced coagulation-sedimentation efficiency of suspended solids in DSR effluents. The DSR effluent presents a promising coagulant for zinc(II) containing wastewaters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Self-Assembled Pyridine-Dipyrrolate Cages.

PubMed

Zhang, Huacheng; Lee, Juhoon; Lammer, Aaron D; Chi, Xiaodong; Brewster, James T; Lynch, Vincent M; Li, Hao; Zhang, Zhan; Sessler, Jonathan L

2016-04-06

An inherently nonlinear pyridine dipyrrolate ligand, namely 2,6-bis(3,4-diethyl-5-carboxy-1H-pyrrol-2yl)pyridine (compound 1), is able to distinguish between different zinc(II) cation sources, namely Zn(acac)2 and Zn(OAc)2, respectively. This differentiation is manifest both in terms of the observed fluorescent behavior in mixed organic media and the reaction chemistry. Treatment of 1 with Zn(acac)2 gives rise to a cage dimer, cage-1, wherein two molecules of compound 1 act as double bridging units to connect two individual cage subunits. As inferred from X-ray crystallographic studies, this cage system consists of discrete zinc dimers with hydroxide bridges that, with the assistance of bound DMF solvent molecules, serve to fix the geometry and orientation of the pyridine dipyrrolate building blocks. When a different zinc source, Zn(OAc)2, is used to carry out an ostensibly similar complexation reaction with compound 1, an acetate-bridged 1D abacus-like cage polymer is obtained as inferred from X-ray diffraction analysis. This extended solid state structure, cage-2, contains individual zinc dimer cage submits and appears stabilized by solvent molecules (DMF) and the counteranion (acetate). Rod-like assemblies are also observed by DLS and SEM. This construct, in contrast to cage-1, proved fluorescent in mixed organic media. The structure of the ligand itself (i.e., in the absence of Zn(II)) was confirmed by X-ray crystallographic analysis and was found to assemble into a supramolecular polymer. Conversion to a dimer form was seen upon the addition of TBAOAc. On the basis of the metric parameters, the structures seen in the solid state are stabilized via hydrogen bonding interactions involving solvent molecules.

Zinc titanate sorbents

DOEpatents

Gupta, R.P.; Gangwal, S.K.; Jain, S.C.

1998-02-03

The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750 to about 950 C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 microns, and about 1 part titanium dioxide having a median particle size of less than about 1 micron. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

Zinc titanate sorbents

DOEpatents

Gupta, Raghubir P.; Gangwal, Santosh K.; Jain, Suresh C.

1998-01-01

The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750.degree. C. to about 950.degree. C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 .mu., and about 1 part titanium dioxide having a median particle size of less than about 1 .mu.. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

New reactions involving the oxidative O-, N-, and C-phosphorylation of organic compounds by phosphorus and phosphides in the presence of metal complexes

NASA Astrophysics Data System (ADS)

Dorfman, Ya A.; Aleshkova, M. M.; Polimbetova, G. S.; Levina, L. V.; Petrova, T. V.; Abdreimova, R. R.; Doroshkevich, D. M.

1993-09-01

The mechanisms of new catalytic reactions leading to the formation of di-, and tri-alkyl phosphates, di- and tri-alkyl phosphites, phosphoramidites, phosphazenes, phosphines, and phosphine oxides from hydrogen, copper, and zinc phosphides and white and red phosphorus are analysed. The mechanisms of the activation of the reactants by metal complexes and of the reactions involving the oxidative P-O, P-N, and P-C coupling of organic compounds to phosphorus and phosphides are considered. The bibliography includes 124 references.

Hydroxyapatite-based sorbents: elaboration, characterization and application for the removal of catechol from the aqueous phase.

PubMed

Sebei, Haroun; Pham Minh, Doan; Lyczko, Nathalie; Sharrock, Patrick; Nzihou, Ange

2017-10-01

Hydroxyapatite (HAP) is highly considered as good sorbent for the removal of metals from the aqueous phase. However, soluble metals co-exist with organic pollutants in wastewaters. But little work has been devoted to investigate the reactivity of HAP for the removal of organic compounds. The main objective of this work is to study the reactivity of HAP-based sorbents for the removal of catechol as a model organic pollutant from an aqueous solution. Thus, HAP sorbents were firstly synthesized using calcium carbonate and potassium dihydrogen phosphate under moderate conditions (25-80°C, atmospheric pressure). A zinc-doped HAP was also used as sorbent, which was obtained from the contact of HAP with an aqueous solution of zinc nitrate. All the sorbents were characterized by different standard physico-chemical techniques. The sorption of catechol was carried out in a batch reactor under stirring at room temperature and pressure. Zinc-doped HAP sorbent was found to be more reactive than non-doped HAP sorbents for the fixation of catechol. The highest sorption capacity was of 15 mg of C per gram of zinc-doped HAP sorbent. The results obtained suggest the reaction scheme of HAP sorbents with metals and organic pollutants when HAP sorbents were used for the treatment of complex wastewaters.

Comparative Genotoxicity and Cytotoxicity of Four Hexavalent Chromium Compounds in Human Bronchial Cells

PubMed Central

Wise, Sandra S.; Holmes, Amie L.; Qin, Qin; Xie, Hong; Katsifis, Spiros P.; Thompson, W. Douglas; Wise, John Pierce

2010-01-01

Hexavalent chromium (Cr(VI)) compounds are well-established human lung carcinogens. Solubility plays an important role in their carcinogenicity with the particulate Cr(VI) compounds being the most carcinogenic. Epidemiology and animal studies suggest that zinc chromate is the most potent particulate Cr(VI) compound, however, there are few comparative data to support these observations. The purpose of this study was to compare the genotoxicity of zinc chromate with two other particulate Cr(VI) compounds, barium chromate and lead chromate, and one soluble Cr(VI) compound, sodium chromate. The clastogenic effects of barium chromate and zinc chromate were similar but lead chromate induced significantly less damage. The levels of DNA damage measured by gamma-H2A.X foci formation were similar for the three particulate chromium compounds. Corrected for chromium uptake differences, we found that zinc chromate and barium chromate were the most cytotoxic and lead chromate and sodium chromate were less cytotoxic. Zinc chromate was more clastogenic than all other chromium compounds and lead chromate was the least clastogenic. There was no significant difference between any of the compounds for the induction of DNA double strand breaks. All together, these data suggest that the difference in the carcinogenic potency of zinc chromate over the other chromium compounds is not due solely to a difference in chromium ion uptake and the zinc cation may in fact have an important role in its carcinogenicity. PMID:20000473

Zinc Oxide—From Synthesis to Application: A Review

PubMed Central

Kołodziejczak-Radzimska, Agnieszka; Jesionowski, Teofil

2014-01-01

Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide. PMID:28788596

Structure-based screening and molecular dynamics simulations offer novel natural compounds as potential inhibitors of Mycobacterium tuberculosis isocitrate lyase.

PubMed

Shukla, Rohit; Shukla, Harish; Sonkar, Amit; Pandey, Tripti; Tripathi, Timir

2018-06-01

Mycobacterium tuberculosis is the etiological agent of tuberculosis in humans and is responsible for more than two million deaths annually. M. tuberculosis isocitrate lyase (MtbICL) catalyzes the first step in the glyoxylate cycle, plays a pivotal role in the persistence of M. tuberculosis, which acts as a potential target for an anti-tubercular drug. To identify the potential anti-tuberculosis compound, we conducted a structure-based virtual screening of natural compounds from the ZINC database (n = 1,67,748) against the MtbICL structure. The ligands were docked against MtbICL in three sequential docking modes that resulted in 340 ligands having better docking score. These compounds were evaluated for Lipinski and ADMET prediction, and 27 compounds were found to fit well with re-docking studies. After refinement by molecular docking and drug-likeness analyses, three potential inhibitors (ZINC1306071, ZINC2111081, and ZINC2134917) were identified. These three ligands and the reference compounds were further subjected to molecular dynamics simulation and binding energy analyses to compare the dynamic structure of protein after ligand binding and the stability of the MtbICL and bound complexes. The binding free energy analyses were calculated to validate and capture the intermolecular interactions. The results suggested that the three compounds had a negative binding energy with -96.462, -143.549, and -122.526 kJ mol -1 for compounds with IDs ZINC1306071, ZINC2111081, and ZINC2134917, respectively. These lead compounds displayed substantial pharmacological and structural properties to be drug candidates. We concluded that ZINC2111081 has a great potential to inhibit MtbICL and would add to the drug discovery process against tuberculosis.

Pyrotechnic Smoke Compositions Containing Boron Carbide

DTIC Science & Technology

2012-06-10

resulting smoke. The inhalation of zinc fumes is known to cause “metal fume fever” and the smoke also contains various chlorinated organic compounds...matches were used to ignite the slurried items. Bare pellets were ignited with electrically heated nickel- chromium wire (hot wire). Small HC smoke

Phytoremediation: Using green plants to clean up contaminated soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.

1996-05-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds ({open_quotes}organics{close_quotes}), and radioactive compounds in soil or water. Current research at Argonne National Laboratory includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. Amore » greenhouse experiment on zinc uptake in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data from Applied Natural Sciences, Inc. (our CRADA partner), indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known {open_quotes}hyperaccumulator{close_quotes} species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

Organic compounds and trace elements in the Pocomoke River and its tributaries

USGS Publications Warehouse

Miller, Cherie V.; Foster, Gregory D.; Huff, Thomas B.; Garbarino, John R.

1999-01-01

In response to concern about recent blooms of the dinoflagellate, Pfiesteria piscicida, samples of sediment and water were collected from the lower Pocomoke River Basin and were screened for trace elements, pesticides, and other organic compounds. A large group of steroid and fatty acid methyl-ester compounds was detected in streamwater using gas chromatography/mass spectroscopy in scan mode. Some of these steroid compounds have been identified and further quantified in bed-sediment extracts. Spatial patterns of the concentrations of cholesterol suggest that these compounds are linked to the runoff of animal wastes into the river. Many of the organic compounds found in the Pocomoke River sediments have not yet been identified, but at least several are in the class of hormone compounds related to estradiols and have the potential to promote endocrine-disrupting effects in aquatic life. Particulate forms of arsenic and zinc are slightly elevated above normal levels for streams, but the sources for these elements are still undetermined. Several pesticides were found in low, parts-per-trillion concentrations, but were within the ranges commonly found in streams of this region.

Cetyltrimethyl Ammonium Bromide as Corrosion Inhibitor for Zinc Used in Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Sun, C. X.; Du, J. J.; Ma, Z. W.; Huang, C. S.; Wu, J. Y.

2018-05-01

A compound inhibitor composed of cetyltrimethyl ammonium bromide (CTAB) and bromohexadecyl pyridine was tested as corrosion inhibitor for zinc in hydrochloric acid. The results of static coupon test show that the compound inhibitor can effectively protect zinc from corrosion and the best concentration ratio is CTAB 50 mg/L and bromohexadecyl pyridine 200 mg/L. The polarization results show that the compound inhibitor will cause a negative shift of E0 of zinc in hydrochloric acid. The EIS (electrchemical impedance spectra) results show that the inhibitor leads to a bigger radius and has one time constant. SEM results show that the CTAB and bromohexadecyl pyridine form a uniform and compact membrane on the surface of zinc that can protect zinc from corroding effectively.

The vertical distribution of selected trace metals and organic compounds in bottom materials of the proposed lower Columbia River export channel, Oregon, 1984

USGS Publications Warehouse

Fuhrer, Gregory J.; Horowitz, Arthur J.

1989-01-01

A proposal to deepen the lower Columbia River navigation channel in Oregon prompted a study of the vertical distribution of selected trace metals and organic compounds in bottom sediments. These data are needed to evaluate the effects of dredging and disposal operations. Elutriation testing of bottom material indicated chemical concentrations as large as 900 ug/L for barium, 6,500 ug/L for manganese, and 14 ug/L for nickel. The amount of oxygen present during elutriation testing of reduced bottom material was shown to have a negligble effect on manganese elutriate-test concentrations, but it did affect barium and iron concentrations. Sediment-associated organochlorine compounds detected in bottom-sediment core samples were as large as 0.1 ug/kg (micrograms/kilogram) for aldrin, 2.0 ug/kg for chlordane, 27 ug/kg for DDD, 5.0 ug/kg for DDE, 0.2 ug/kg for DDT, 0.2 ug/kg for dieldrin, 37 ug/kg for PCB 's 1.0 ug/kg for PCN 's and 1.0 ug/kg for heptachlor epoxide. Concentrations of cadmium, lead, and zinc in selected cores were found to exceed those of local basalts. Concentrations of cadmium, lead, and zinc were as large as 3.6 ug/g, 26 ug/g, and 210 ug/g respectively. Bottom-sediment concentrations of cadmium , chromium, copper, iron, and zinc associated with the less-than-100-micrometer size fraction are larger than those associated with the greater-than-100-micrometer fraction. (USGS)

Crystalline perfection, optical and piezoelectric properties of a novel semi-organic single crystal: Zinc guanidinium sulphate

NASA Astrophysics Data System (ADS)

Nandhini, S.; Murugakoothan, P.

2018-04-01

Zinc Guanidinium Sulfate (ZGuS), a semi-organic single crystal, was synthesized using slow evaporation solution growth technique. It is a non-centrosymmetric crystal with space group I4 ¯2d . The crystalline nature of the crystal and the strain were determined using powder X-ray diffraction analysis. The crystalline perfection of the grown crystal was revealed using HR-XRD analysis. The UV-vis-NIR transmittance spectrum depicts 60% transparency with lower-cut off wavelength of 210 nm. The emission spectrum of the crystal was determined using photoluminescence study. Piezoelectricity was confirmed by determining the piezoelectric charge coefficient (d33). These findings shows that the title compound can be employed for photonic and transducer applications.

[Health hazards resulting from exposure to zinc and its inorganic compounds in industry].

PubMed

Pakulska, Daria; Czerczak, Sławomir

2017-10-17

This article deals with health risks resulting from exposure to zinc and its inorganic compounds in industry. The main source of zinc exposure are fumes generated during thermal and chemical processes, mainly zinc oxide fume formed by immediate oxidation of metallic zinc vapor formed during high-temperature processes, as well as dust generated during the mechanical processing of zinc-containing materials. It is recognized that zinc ions are responsible for health effects of exposure to dust/fumes of the majority of zinc compounds, and the final effect of exposure depends on the degree of dispersion of dusts/fumes suspended in the air. Since the effects of exposure depends on the particle size, occupational exposure limits have began to be established separately for respirable and inhalable fractions. A critical effect of acute exposure to respirable fraction is a "fume fever" which in chronic exposure occurs as an effect associated with recurrent symptoms of acute poisoning. Impaired lung function and asthma symptoms are considered to be the main effects of exposure to inhalable fraction. Due to the limited number of the available data it is not possible to assess carcinogenicity, reproductive toxicity and teratogenicity of zinc and its compounds. The aim of the study was to analyze the major health hazards resulting from occupational exposure to zinc and its inorganic compounds in the context of their physico-chemical properties, a wide range of applications and occupational exposure data. Med Pr 2017;68(6):779-794. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Synthesis and characterization of an effective organic/inorganic hybrid green corrosion inhibitive complex based on zinc acetate/Urtica Dioica

NASA Astrophysics Data System (ADS)

Salehi, E.; Naderi, Reza; Ramezanzadeh, B.

2017-02-01

This study aims at synthesis and characterization of an effective corrosion inhibitive complex based on zinc acetate/Urtica Dioica (ZnA-U.D) for corrosion protection of mild steel in chloride solution. The chemical structure and morphology of the complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion protection performance of the mild steel samples dipped in 3.5 wt.% NaCl solutions with and without ZnA-U.D extract was investigated by visual observations, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization test. Results revealed that the ZnA successfully chelated with organic inhibitive compounds (i.e Quercetin, Quinic acid, Caffeic acid, Hystamine and Serotonin) present in the U.D extract. The electrochemical measurements revealed the effective inhibition action of ZnA-U.D complex in the sodium chloride solution on the mild steel. The synergistic effect between Zn2+ and organic compounds present in the U.D extract resulted in protective film deposition on the steel surface, which was proved by SEM and XPS analyses.

Chemical quality of the Saw Mill River, Westchester County, New York, 1981-83

USGS Publications Warehouse

Rogers, R.J.

1984-01-01

Surface waters, bottom sediments and coatings formed on artificial substrates (ceramic tiles) were analyzed to evaluate the chemical quality of the Saw Mill River, New York. Heavy metals, nutrients, and organic contaminants were studied. Dissolved orthophosphate concentrations were highest in the lower third of the river. Dissolved manganese was the only metal to exceed U.S. Environmental Protection Agency water-quality criteria. Arsenic, cadmium, copper, lead, and zinc concentrations were highest in waters from the lowest 4 river miles. Concentrations of copper, lead, and zinc in bottom sediments from the lowest 3 river miles were greater than in upstream sediments. Concentrations of nine heavy metals were higher on tiles emplaced below river mile 3 than on tiles upstream. Few organic compounds were detected in the water column; none persisted at all sites. Chlordane, DDD, DDE, DDT, dieldrin, and polychlorinated biphenyls (PCB's) were found in bottom sediments throughout the basin. PCB concentrations were highest in the lowest 6 river miles; the other organic compounds exhibited no spatial patterns. Polynuclear aromatic hydrocarbons were most abundant in bottom sediments from the lowest 2 river miles. Collectively the distribution of contaminants indicates that river quality deteriorates in the lower, more heavily urbanized reach. (USGS)

Molecular Dynamics Simulations of Novel Potential Inhibitors for Penicillin Binding Protein 2B of the Resistant 5204 Strain of Streptococcus Pneumoniae.

PubMed

Suvaithenamudhan, Suvaiyarasan; Parthasarathy, Subbiah

2017-01-01

Top five best hit compounds (ZINC59376795, ZINC60175365, ZINC36922620, ZINC39550705 and ZINC36953975) were obtained through our high throughput virtual screening (HTVS) analysis with resistant 5204-PBP2B (5204 Penicillin Binding Protein 2B) and sensitive R6-PBP2B (R6 Penicillin Binding Protein 2B) proteins of Streptococcus pneumoniae. To gain insight in molecular docking and dynamics simulations of these top five best hit compounds with both resistant 5204-PBP2B and sensitive R6-PBP2B targets. We have employed Glide XP docking and molecular dynamics simulations of these five best hit compounds with 5204-PBP2B and R6-PBP2B targets. The stability analysis has been carried out through DFT, prime-MM/GBSA binding free energy, RMSD, RMSF and Principal Component Analysis. The reference drug, penicillin G forms stable complex with sensitive R6-PBP2B protein. Similar stability is observed for the mutant resistant 5204-PBP2B with the top scoring compound ZINC592376795 which implies that this compound may act as an effective potential inhibitor. The compound ZINC59376795 forms a total of five hydrogen bonds with resistant 5204-PBP2B protein of which three are with mutated residues. Similarly, the other four compounds including penicillin G also form hydrogen bonds with mutated residue. The MD simulations and stability analysis of the complexes of wild and mutant forms are evaluated for a trajectory period of 16ns and further MD simulations of ZINC59376795 with resistant 5204-PBP2B and sensitive R6-PBP2B confirmed the stability for 50 ns. These results suggest that the top five best hit compounds are found to be a promising gateway for the further development of anti-pneumococcal therapeutics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A Grignard-like Organic Reaction in Water

NASA Astrophysics Data System (ADS)

Breton, Gary W.; Hughey, Christine A.

1998-01-01

The addition of a Grignard reagent to a carbonyl-containing compound to form an alcohol is an important reaction to demonstrate in organic chemistry laboratory courses. However, the reaction presents several practical problems for the lab instructor including the need for anhydrous solvents (e.g., ether), dry glassware, and the occasional problem of slow reaction initiation. We have scaled, and tested, a known Grignard-like reaction between allyl bromide and benzaldehyde mediated by zinc metal in aqueous media. The procedure retains the desirable features of the traditional Grignard reaction, while eliminating some of the commonly encountered difficulties. Thus, addition of allyl bromide (1.2 eq) to benzaldehyde and zinc in a two-phase mixture of THF and saturated aqueous NH4Cl afforded addition product 1-phenyl-3-buten-1-ol in 70-85% yields.

Effect of a zinc L-carnosine compound on acid-induced injury in canine gastric mucosa ex vivo.

PubMed

Hill, Tracy L; Blikslager, Anthony T

2012-05-01

To examine whether a zinc L-carnosine compound used for treatment of suspected gastric ulcers in dogs ameliorates acid-induced injury in canine gastric mucosa. Gastric mucosa from 6 healthy dogs. Mucosa from the gastric antrum was harvested from 6 unadoptable shelter dogs immediately after euthanasia and mounted on Ussing chambers. The tissues were equilibrated for 30 minutes in neutral Ringer's solution prior to incubation with acidic Ringer's solution (HCl plus Ringer's solution [final pH, 1.5 to 2.5]), acidic Ringer's solution plus zinc L-carnosine compound, or zinc L-carnosine compound alone. Tissues were maintained for 180 minutes in Ussing chambers, during which permeability was assessed by measurement of transepithelial electrical resistance. After the 180-minute treatment period, tissues were removed from Ussing chambers and labeled with immunofluorescent anti-active caspase-3 antibody as an indicator of apoptosis. Permeability of the gastric mucosa was significantly increased in a time-dependent manner by addition of HCl, whereas control tissues maintained viability for the study period. Change in permeability was detected within the first 15 minutes after acid application and progressed over the subsequent 150 minutes. The zinc L-carnosine compound had no significant effect on this increase in permeability. Apoptosis was evident in acid-treated tissues but not in control tissues. The zinc L-carnosine compound did not protect against development of apoptosis. Addition of HCl caused a dose-dependent increase in gastric permeability over time and apparent induction of apoptosis as determined on the basis of immunofluorescence. However, there was no significant protective effect of a zinc L-carnosine compound. Nonetheless, results suggested the utility of this method for further studies of canine gastric injury.

Effect of organic matter on cyanide removal by illuminated titanium dioxide or zinc oxide nanoparticles

PubMed Central

2013-01-01

Effect of different type of organic compounds (humic acid, oxalate, ethylenediaminetetraacetic acid, nitrilotriacetic acid, phenol) on the photocatalytic removal of cyanide with TiO2 or ZnO was studied in this work with variation of the solution pH, contact time, initial cyanide concentration and type of organic compounds. Photocatalytic oxidation efficiency of cyanide with TiO2 was greatly affected by the solution pH. It increased as the solution pH decreased. Also maximum removal of cyanide by ZnO was observed near at neutral pH because of the reduced photocatalytic activity of ZnO at exceedingly low and high pH values originated from either acidic/photochemical corrosion of the catalyst and/or surface passivation with Zn(OH)2. Removal efficiency of cyanide greatly decreased in the presence of humic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid compared to that without presence of organic compound because of the competitive oxidation as well as surface blocking by relatively large organic compounds. The oxidation pattern of cyanide was better described by first-order kinetic model. Finally photocatalytic reaction with TiO2 or ZnO can be effectively applied to treat synthetic wastewater contaminated with cyanide. PMID:24499704

Selected organic compounds and trace elements in streambed sediments and fish tissues, Cook Inlet Basin, Alaska

USGS Publications Warehouse

Frenzel, Steven A.

2000-01-01

Organochlorines, semivolatile organic compounds (SVOCs), and trace elements were investigated in streambed sediments and fish tissues at selected sites in the Cook Inlet Basin, Alaska, during 1998. At most sites, SVOCs and organochlorine compounds were either not detected or detected at very low concentrations. Chester Creek at Arctic Boulevard at Anchorage, which was the only site sampled with a significant degree of development in the watershed, had elevated levels of many SVOCs in streambed sediment. Coring of sediments from two ponds on Chester Creek confirmed the presence of elevated concentrations of a variety of organic compounds. Moose Creek, a stream with extensive coal deposits in its watershed, had low concentrations of numerous SVOCs in streambed sediment. Three sites located in national parks or in a national wildlife refuge had no detectable concentrations of SVOCs. Trace elements were analyzed in both streambed sediments and tissues of slimy sculpin. The two media provided similar evidence for elevated concentrations of cadmium, lead, and zinc at Chester Creek. In this study, 'probable effect levels '(PELs) were determined from sediments finer than 0.063 millimeters, where concentrations tend to be greatest. Arsenic and chromium concentrations exceeded the PEL at eight and six sites respectively. Zinc exceeded the PEL at one site. Cadmium and copper concentrations were smaller than the PEL at all sites. Mercury concentrations in streambed sediments from the Deshka River were near the PEL, and selenium concentrations at that site also appear to be elevated above background levels. At half the sites where slimy sculpin were sampled, selenium concentrations were at levels that may cause adverse effects in some species.

Phytoremediation: using green plants to clean up contaminate soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.; Gatliff, E.G.

1996-07-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. Our research includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. A greenhouse experiment on zinc uptakemore » in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known ``hyperaccumulator`` species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

A Novel Polyaminocarboxylate Compound To Treat Murine Pulmonary Aspergillosis by Interfering with Zinc Metabolism.

PubMed

Laskaris, Paris; Vicentefranqueira, Rocío; Helynck, Olivier; Jouvion, Grégory; Calera, José Antonio; du Merle, Laurence; Suzenet, Franck; Buron, Frédéric; de Sousa, Rodolphe Alves; Mansuy, Daniel; Cavaillon, Jean-Marc; Latgé, Jean-Paul; Munier-Lehmann, Hélène; Ibrahim-Granet, Oumaima

2018-06-01

Aspergillus fumigatus can cause pulmonary aspergillosis in immunocompromised patients and is associated with a high mortality rate due to a lack of reliable treatment options. This opportunistic pathogen requires zinc in order to grow and cause disease. Novel compounds that interfere with fungal zinc metabolism may therefore be of therapeutic interest. We screened chemical libraries containing 59,223 small molecules using a resazurin assay that compared their effects on an A. fumigatus wild-type strain grown under zinc-limiting conditions and on a zinc transporter knockout strain grown under zinc-replete conditions to identify compounds affecting zinc metabolism. After a first screen, 116 molecules were selected whose inhibitory effects on fungal growth were further tested by using luminescence assays and hyphal length measurements to confirm their activity, as well as by toxicity assays on HeLa cells and mice. Six compounds were selected following a rescreening, of which two were pyrazolones, two were porphyrins, and two were polyaminocarboxylates. All three groups showed good in vitro activity, but only one of the polyaminocarboxylates was able to significantly improve the survival of immunosuppressed mice suffering from pulmonary aspergillosis. This two-tier screening approach led us to the identification of a novel small molecule with in vivo fungicidal effects and low murine toxicity that may lead to the development of new treatment options for fungal infections by administration of this compound either as a monotherapy or as part of a combination therapy. Copyright © 2018 American Society for Microbiology.

New 3 D Tubular Porous Structure of an Organic-Zincophosphite Framework with Interesting Gas Adsorption and Luminescence Properties.

PubMed

Wang, Chih-Min; Lee, Li-Wei; Chang, Tsung-Yuan; Fan, Bing-Lun; Wang, Chih-Ling; Lin, Hsiu-Mei; Lu, Kuang-Lieh

2016-11-02

A new 3D tubular zinc phosphite, Zn 2 (C 22 H 22 N 8 ) 0.5 (HPO 3 ) 2 ⋅H 2 O (1), incorporating a tetradentate organic ligand was synthesized under hydro(solvo)thermal conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 is the first example of inorganic zincophosphite chains being interlinked through 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene to form a tubular porous framework with unusual organic-inorganic hybrid channels. The thermal and chemical stabilities, high capacity for CO 2 adsorption compared to that for N 2 adsorption, and interesting optical properties of LED devices fabricated using this compound were also studied. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trace elements and organic compounds in bed sediment from selected streams in southern Louisiana, 1998

USGS Publications Warehouse

Skrobialowski, Stanley C.

2002-01-01

Bed-sediment samples from 21 selected streams in southern Louisiana were collected and analyzed for the presence of trace elements and organic compounds during 1998 as part of the U.S. Geological Survey National Water-Quality Assessment Program. Concentrations of selected trace elements and organic compounds were compared on the basis of sediment-quality criteria, land use, and grain size; concentrations of selected trace elements also were compared with concentrations from previous studies. Concentrations of seven selected trace elements and 21 organic compounds were evaluated with sediment-quality criteria established by the Canadian Council of Ministers of the Environment. Concentrations of selected trace elements and organic compounds were highest at sites draining urban and agricultural areas and may result from cumulative effects of relatively high percentages of fine-grained material, iron, and organic material. Concentrations exceeding sediment-quality criteria for the protection of aquatic life occurred most frequently at Bayou Grosse Tete at Rosedale and Bayou Lafourche below weir at Thibodaux. Exceedance of Interim Sediment Quality Guidelines occurred most frequently for arsenic and chromium. Trace-element concentrations in fine-grained samples were compared with concentrations in bulk samples and were determined to be significantly different, and concentrations were generally higher in finegrained sediment. Shapiro-Wilk, paired t-test, and Wilcoxon rank sum statistical procedures, with an alpha of 0.05, were used to compare concentrations of 21 trace elements, total organic carbon, and total carbon in finegrained and bulk sediment samples for 19 sites. Significant differences were determined between fine-grained and bulk sediment samples for aluminum, barium, beryllium, chromium, copper, iron, lithium, nickel, phosphorus, selenium, titanium, and zinc concentrations. Of 133 paired concentrations, 69 percent were greater in fine-grained samples, and 23 percent were greater in bulk samples. Comparisons with data from previous studies indicate increases by more than 20 percent in concentrations of antimony at Bayou Lafourche below weir at Thibodaux, arsenic and chromium at Tickfaw River at Liverpool, lead at Bayou Lafourche below weir at Thibodaux, and zinc at Bayou Lafourche below weir at Thibodaux and Vermilion River at Perry. Historic comparisons also indicate decreases by more than 20 percent in concentrations of chromium at Bayou des Cannes near Eunice and mercury at Mermentau River at Mermentau.

Carbon- versus sulphur-based zinc binding groups for carbonic anhydrase inhibitors?

PubMed

Supuran, Claudiu T

2018-12-01

A set of compounds incorporating carbon-based zinc-binding groups (ZBGs), of the type PhX (X = COOH, CONH 2 , CONHNH 2 , CONHOH, CONHOMe), and the corresponding derivatives with sulphur(VI)-based ZBGs (X = SO 3 H, SO 2 NH 2 , SO 2 NHNH 2 , SO 2 NHOH, SO 2 NHOMe) were tested as inhibitors of all mammalian isoforms of carbonic anhydrase (CA, EC 4.2.1.1), CA I-XV. Three factors connected with the ZBG influenced the efficacy as CA inhibitor (CAI) of the investigated compounds: (i) the pKa of the ZBG; (ii) its geometry (tetrahedral, i.e. sulphur-based, versus trigonal, i.e. carbon-based ZBGs), and (iii) orientation of the organic scaffold induced by the nature of the ZBG. Benzenesulphonamide was the best inhibitor of all isoforms, but other ZBGs led to interesting inhibition profiles, although with an efficacy generally reduced when compared to the sulphonamide. The nature of the ZBG also influenced the CA inhibition mechanism. Most of these derivatives were zinc binders, but some of them (sulfonates, carboxylates) may interact with the enzyme by anchoring to the zinc-coordinated water molecule or by other inhibition mechanisms (occlusion of the active site entrance, out of the active site binding, etc.). Exploring structurally diverse ZBGs may lead to interesting new developments in the field of CAIs.

Zinc phosphate conversion coatings

DOEpatents

Sugama, Toshifumi

1997-01-01

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

Zinc phosphate conversion coatings

DOEpatents

Sugama, T.

1997-02-18

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

A large scale virtual screen of DprE1.

PubMed

Wilsey, Claire; Gurka, Jessica; Toth, David; Franco, Jimmy

2013-12-01

Tuberculosis continues to plague the world with the World Health Organization estimating that about one third of the world's population is infected. Due to the emergence of MDR and XDR strains of TB, the need for novel therapeutics has become increasing urgent. Herein we report the results of a virtual screen of 4.1 million compounds against a promising drug target, DrpE1. The virtual compounds were obtained from the Zinc docking site and screened using the molecular docking program, AutoDock Vina. The computational hits have led to the identification of several promising lead compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis and characterization of nanometric zinc oxide for a stationary phase in liquid chromatography

NASA Astrophysics Data System (ADS)

Gordillo-Delgado, F.; Soto-Barrera, C. C.; Plazas-Saldaña, J.

2017-01-01

The increasing demand for equipment to remove organic compounds in industry and research activity has led to evaluate nanometric zinc oxide (ZnO). In this work, we present the ZnO nanoparticles synthesis for reusing of discarded columns, as a low-cost alternative. The compound was obtained by sol-gel technique using zinc chloride and sodium hydroxide as precursors and a drying temperature of 169°C. An X-ray diffractometer was used to estimate the average particle size at 20.3±0.2nm the adsorption capacity was 0.0144L/g and the chemical resistance was tested with HCl and NaOH. The ZnO nanopowder was packed with 100psi pressure in an empty C-18 column cavity. The column packing resolution was evaluated using a high performance liquid chromatographer (HPLC-Thermo Scientific Dionex UltiMate 3000); using a caffeine standard, the following parameters were established: solvent flow: 1.2mL/min, average column temperature: 40°C, running time: 10 minutes, mobile phase acetonitrile-water composition (9:1). These results validate the potential of ZnO nanopowder as a column packing material in HPLC technique.

Effects of Zinc Gluconate and 2 Other Divalent Cationic Compounds on Olfactory Function in Mice

PubMed Central

Duncan-Lewis, Christopher A; Lukman, Roy L; Banks, Robert K

2011-01-01

Intranasal application of zinc gluconate has commonly been used to treat the common cold. The safety of this treatment, however, has come into question recently. In addition to a United States recall of a homeopathic product that contains zinc gluconate, abundant literature reports cytotoxic effects of zinc on the olfactory epithelium. Additional research suggests that divalent cations (such as zinc) can block ion channels that facilitate the transduction of odors into electrical signals on the olfactory epithelium. The purpose of the current study was 2-fold: to confirm whether zinc gluconate causes anosmia and to reveal whether any other divalent cationic compounds produce a similar effect. Groups of mice underwent a buried food-pellet test to gauge olfactory function and then were nasally irrigated with 1 of 3 divalent cationic compounds. When tested after treatment, mice irrigated with zinc gluconate and copper gluconate experienced a marked increase in food-finding time, indicating that they had lost their ability to smell a hidden food source. Control mice irrigated with saline had a significantly lower increase in times. These results confirm that zinc gluconate can cause anosmia and reveal that multiple divalent cations can negatively affect olfaction. PMID:22330252

Process and apparatus for formation of photovoltaic compounds

DOEpatents

Hall, Robert B.; Rocheleau, Richard E.

1985-01-01

The invention relates to a process and apparatus for formation and deposition of thin films on a substrate, in a vacuum, by evaporation of the elements to form a Zn.sub.x Cd.sub.1-x S compound having a preselected fixed ratio of cadmium to zinc, characterized by the evaporation of cadmium and zinc at a rate the ratio of which is proportional to the stoichiometric ratio of those elements in the intended compound and evaporation of sulfur at a rate at least twice the combined rates of cadmium and zinc, and at least twice that required by the stoichiometry of the intended compound.

Synthesis, supramolecular behavior, and in vitro photodynamic activities of novel zinc(II) phthalocyanines "side-strapped" with crown ether bridges.

PubMed

Chen, Xing-Wei; Ke, Mei-Rong; Li, Xing-Shu; Lan, Wen-Liang; Zhang, Miao-Fen; Huang, Jian-Dong

2013-12-01

Two new tetra- or di-α-substituted zinc(II) phthalocyanines 5 and 6 have been prepared through a "side-strapped" method. In the molecules, the adjacent benzene rings of the phthalocyanine core are linked at α-position through a triethylene glycol bridge to form a hybrid aza-/oxa-crown ether. The tetra-α-substituted phthalocyanine 5 shows an eclipsed self-assembly property in CH2Cl2 and the effect on the di-α-substituted analogue 6 is significantly weakened. Furthermore, the crown ethers of these compounds can selectively complex with Fe(3+) or Cu(2+) ion in DMF, leading to formation of J-aggregated nano-assemblies, which can be disaggregated in the presence of some organic or inorganic ligands, such as triethylamine, tetramethylethylenediamine, CH3COO(-), or OH(-). In addition, both compounds are efficient singlet oxygen generators with the singlet oxygen quantum yields (Φ(Δ)) of 0.54-0.74 in DMF relative to unsubstituted zinc(II) phthalocyanine (Φ(Δ)=0.56). They exhibit photodynamic activities toward HepG2 human hepatocarcinoma cells, but the compound 6, which has more than 40-fold lower IC50 value (0.08 μM) compared to the analogue 5 (IC50=3.31 μM), shows remarkablely higher in vitro photocytotoxicity due to its significantly higher cellular uptake and singlet oxygen generation efficiency. The results suggest that these compounds can serve as promising multifunctional materials both in (opto)electronic field and photodynamic therapy. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trichomes of Tobacco Excrete Zinc as Zinc-Substituted Calcium Carbonate and Other Zinc-Containing Compounds1[W

PubMed Central

Sarret, Géraldine; Harada, Emiko; Choi, Yong-Eui; Isaure, Marie-Pierre; Geoffroy, Nicolas; Fakra, Sirine; Marcus, Matthew A.; Birschwilks, Mandy; Clemens, Stephan; Manceau, Alain

2006-01-01

Tobacco (Nicotiana tabacum L. cv Xanthi) plants were exposed to toxic levels of zinc (Zn). Zn exposure resulted in toxicity signs in plants, and these damages were partly reduced by a calcium (Ca) supplement. Confocal imaging of intracellular Zn using Zinquin showed that Zn was preferentially accumulated in trichomes. Exposure to Zn and Zn + Ca increased the trichome density and induced the production of Ca/Zn mineral grains on the head cells of trichomes. These grains were aggregates of submicrometer-sized crystals and poorly crystalline material and contained Ca as major element, along with subordinate amounts of Zn, manganese, potassium, chlorine, phosphorus, silicon, and magnesium. Micro x-ray diffraction revealed that the large majority of the grains were composed essentially of metal-substituted calcite (CaCO3). CaCO3 polymorphs (aragonite and vaterite) and CaC2O4 (Ca oxalate) mono- and dihydrate also were identified, either as an admixture to calcite or in separate grains. Some grains did not diffract, although they contained Ca, suggesting the presence of amorphous form of Ca. The presence of Zn-substituted calcite was confirmed by Zn K-edge micro-extended x-ray absorption fine structure spectroscopy. Zn bound to organic compounds and Zn-containing silica and phosphate were also identified by this technique. The proportion of Zn-substituted calcite relative to the other species increased with Ca exposure. The production of Zn-containing biogenic calcite and other Zn compounds through the trichomes is a novel mechanism involved in Zn detoxification. This study illustrates the potential of laterally resolved x-ray synchrotron radiation techniques to study biomineralization and metal homeostasis processes in plants. PMID:16731580

Structural Studies on Intact Clostridium botulinum Neurotoxins Complexed with Inhibitors Leading to Drug Design

DTIC Science & Technology

2008-02-01

via virtual screening. These compounds include small molecules – transition state analogues and benzimidazoles . We have determined the crystal...project period. It has been established that benzimidazole compounds are good zinc chealators and since botulinum neurotoxin catalytic domains are zinc...endopeptidases we first selected a subset of compounds containing benzimidazole moieties. We pulled out nearly 9000 compound containing both

Zinc and Compounds

Integrated Risk Information System (IRIS)

Zinc and Compounds ; CASRN 7440 - 66 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

Powder X-ray diffraction, infrared and 13C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Taylor, Richard A.

2015-03-01

A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state 13C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc > 8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

Compound heterozygous mutations in SLC30A2/ZnT2 results in low milk zinc concentrations: a novel mechanism for zinc deficiency in a breast-fed infant.

PubMed

Itsumura, Naoya; Inamo, Yasuji; Okazaki, Fumiko; Teranishi, Fumie; Narita, Hiroshi; Kambe, Taiho; Kodama, Hiroko

2013-01-01

Zinc concentrations in breast milk are considerably higher than those of the maternal serum, to meet the infant's requirements for normal growth and development. Thus, effective mechanisms ensuring secretion of large amounts of zinc into the milk operate in mammary epithelial cells during lactation. ZnT2 was recently found to play an essential role in the secretion of zinc into milk. Heterozygous mutations of human ZnT2 (hZnT2), including H54R and G87R, in mothers result in low (>75% reduction) secretion of zinc into the breast milk, and infants fed on the milk develop transient neonatal zinc deficiency. We identified two novel missense mutations in the SLC30A2/ZnT2 gene in a Japanese mother with low milk zinc concentrations (>90% reduction) whose infant developed severe zinc deficiency; a T to C transition (c.454T>C) at exon 4, which substitutes a tryptophan residue with an arginine residue (W152R), and a C to T transition (c.887C>T) at exon 7, which substitutes a serine residue with a leucine residue (S296L). Biochemical characterization using zinc-sensitive DT40 cells indicated that the W152R mutation abolished the abilities to transport zinc and to form a dimer complex, indicating a loss-of-function mutation. The S296L mutation retained both abilities but was extremely destabilized. The two mutations were found on different alleles, indicating that the genotype of the mother with low milk zinc was compound heterozygous. These results show novel compound heterozygous mutations in the SLC30A2/ZnT2 gene causing zinc deficiency in a breast-fed infant.

Compound Heterozygous Mutations in SLC30A2/ZnT2 Results in Low Milk Zinc Concentrations: A Novel Mechanism for Zinc Deficiency in a Breast-Fed Infant

PubMed Central

Itsumura, Naoya; Inamo, Yasuji; Okazaki, Fumiko; Teranishi, Fumie; Narita, Hiroshi; Kambe, Taiho; Kodama, Hiroko

2013-01-01

Zinc concentrations in breast milk are considerably higher than those of the maternal serum, to meet the infant's requirements for normal growth and development. Thus, effective mechanisms ensuring secretion of large amounts of zinc into the milk operate in mammary epithelial cells during lactation. ZnT2 was recently found to play an essential role in the secretion of zinc into milk. Heterozygous mutations of human ZnT2 (hZnT2), including H54R and G87R, in mothers result in low (>75% reduction) secretion of zinc into the breast milk, and infants fed on the milk develop transient neonatal zinc deficiency. We identified two novel missense mutations in the SLC30A2/ZnT2 gene in a Japanese mother with low milk zinc concentrations (>90% reduction) whose infant developed severe zinc deficiency; a T to C transition (c.454T>C) at exon 4, which substitutes a tryptophan residue with an arginine residue (W152R), and a C to T transition (c.887C>T) at exon 7, which substitutes a serine residue with a leucine residue (S296L). Biochemical characterization using zinc-sensitive DT40 cells indicated that the W152R mutation abolished the abilities to transport zinc and to form a dimer complex, indicating a loss-of-function mutation. The S296L mutation retained both abilities but was extremely destabilized. The two mutations were found on different alleles, indicating that the genotype of the mother with low milk zinc was compound heterozygous. These results show novel compound heterozygous mutations in the SLC30A2/ZnT2 gene causing zinc deficiency in a breast-fed infant. PMID:23741301

Bicyclic tetrapeptide histone deacetylase inhibitors with methoxymethyl ketone and boronic acid zinc-binding groups.

PubMed

Islam, Md Nurul; Islam, Md Shahidul; Hoque, Md Ashraful; Kato, Tamaki; Nishino, Norikazu; Ito, Akihiro; Yoshida, Minoru

2014-12-01

Histone deacetylase (HDAC) inhibitors are a class of potential therapeutics for the treatment of cancer. Bicyclic tetrapeptides equipped with methoxymethyl ketone and boronic acid as zinc-binding group were designed and synthesized. The inhibitory activities of these compounds were evaluated against HDAC enzymes. The cell-free and cell-based assay data showed that both potency and selectivity changed with the change in zinc-binding group. Boronic acid-based compound showed poor activity whereas methoxymethyl ketone-based compound displayed impressive activity in both cell-free and cell-based conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Environmental behavior of cement-based stabilized foundry sludge products incorporating additives.

PubMed

Ruiz, M C; Irabien, A

2004-06-18

A series of experiments were conducted to stabilize the inorganic and organic pollutants in a foundry sludge from a cast iron activity using Portland cement as binder and three different types of additives, organophilic bentonite, lime and coal fly ash. Ecotoxicological and chemical behavior of stabilized mixes of foundry sludge were analyzed to assess the feasibility to immobilize both types of contaminants, all determined on the basis of compliance leaching tests. The incorporation of lime reduces the ecotoxicity of stabilized mixes and enhances stabilization of organic pollutants obtaining better results when a 50% of cement is replaced by lime. However, the alkalinity of lime increases slightly the leached zinc up to concentrations above the limit set under neutral conditions by the European regulations. The addition of organophilic bentonite and coal fly ash can immobilize the phenolic compounds but are inefficient to reduce the ecotoxicity and mobility of zinc of final products.

Evaluation of organic compounds and trace elements in Amazon Creek Basin, Oregon, September 1990

USGS Publications Warehouse

Rinella, F.A.

1993-01-01

Water and bottom sediment were collected from Amazon Creek, Oregon during a summer low-flow condition and analyzed for different classes of organic compounds, including many from the U.S. Environmental Protection Agency's priority pollutant list. Bottom sediment also was analyzed for trace elements typically associated with urban runoff. Trace-element concentrations in the less than 63 micrometer fraction of Amazon Creek bottom-sediment samples were compared with baseline concentrations (expected 95 percent confidence range) for soils from the Western United States and with concen- trations found in bottom sediment from the Willamette River Basin. Total-digestion concentrations of antimony, arsenic, cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, silver, titanium, and zinc were enriched at some or all sites sampled. Whole-water samples from some sites contained concentrations of several chlorophenoxy-acid herbicides, the organophosphorus insecticide diazinon, and several semivolatile priority pollutants. Classes of compounds not detected in whole-water samples included carbamate insecticides, triazine and other nitrogen-containing herbicides, and purgeable organic compounds. Bottom-sediment samples contained many organochlorine compounds, including chlordane, DDT plus metabolites, dieldrin, endrin, heptachlor epoxide (a metabolite of heptachlor), and PCBs at some or all sites sampled. Twenty-four of 54 semivolatile compounds were detected in bottom- sediment samples at some or all sites sampled.

Synthesis, crystal structures and luminescent properties of zinc(II) metal–organic frameworks constructed from terpyridyl derivative ligand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN

2014-08-15

Five zinc(II) metal–organic frameworks, [Zn{sub 3}(344-pytpy){sub 2}Cl{sub 6}]{sub n}·n(H{sub 2}O) (1), [Zn(344-pytpy)(ox)]{sub n} (2), [Zn{sub 2}(344-pytpy)(bdc){sub 2}]{sub n}·1.5n(H{sub 2}O) (3), [Zn{sub 2}(344-pytpy){sub 2} (sfdb){sub 2}]{sub n}·1.5n(H{sub 2}O) (4) and [Zn{sub 3}(344-pytpy){sub 2}(btc){sub 2}]{sub n}·2n(H{sub 2}O) (5), (344-pytpy=4′-(3-pyridyl)-4,2′:6′,4″-terpyridine, H{sub 2}ox=oxalic acid, H{sub 2}bdc=1,4-benzenedi-carboxylic acid, H{sub 2}sfdb=4,4′-sulfonyldibenzoic acid and H{sub 3}btc=1,3,5-benzene-tricarboxylic acid) have been prepared by hydrothermal reactions. Compound 1 is a 1D chain structure, in which 344-pytpy ligand links three Zn{sup II} centers through three of terminal N-donors. Compound 2 is a 4-connected 3D framework with the dia topological net and the Schläfli symbol of 6{sup 6}. Compound 3 displays amore » unusual 3-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,3,4)-connected topological net with the Schläfli symbol of (4.8{sup 2})(4.8{sup 5})(8{sup 3}). Compound 4 features a two-fold interpenetrating 4-connected 2D framework with the sql topological net and the Schläfli symbol of (4{sup 4}.6{sup 2}). Compound 5 is a new self-interpenetrating (3,3,4,4)-connected topological net with the Schläfli symbol of (6.8{sup 2}){sub 2}(6{sup 2}.8{sup 2}.10.12)(6{sup 2}.8{sup 3}.10){sub 2}(6{sup 2}.8){sub 2}. The luminescence properties of 1–5 have been investigated by emission spectra and they possess great thermal stabilities which can be stable up to around 400 °C. - Graphical abstract: Five new Zn(II) metal–organic frameworks based on dicarboxylate and terpyridyl derivative ligands have been synthesized by hydrothermal reactions, giving networks from 1D to 3D structures. The thermal stability and luminescent property have been investigated. - Highlights: • Five zinc(II) metal–organic frameworks have been prepared under hydrothermal conditions. • Their crystal and topological structures have been investigated. • The luminescent properties have been investigated. • They possess great thermal stabilities which can be stable up to around 400 °C.« less

Effects of leachate from crumb rubber and zinc in green roofs on the survival, growth, and resistance characteristics of Salmonella enterica subsp. enterica serovar Typhimurium.

PubMed

Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H; Herson, Diane S

2014-05-01

The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain.

Dimensionality Alteration and Intra- versus Inter-SBU Void Encapsulation in Zinc Phosphate Frameworks.

PubMed

Dar, Aijaz A; Bhat, Gulzar A; Murugavel, Ramaswamy

2016-06-06

4,4'-Bipyridine-N-oxide (BIPYMO, 1), a less commonly employed coordination polymer linker, has been used as a ditopic spacer to bridge double-four-ring (D4R) zinc phosphate clusters to form novel framework coordination polymers. Zinc phosphate framework compounds [Zn4(X-dipp)4(BIPYMO)2]n·2MeOH [X = H (2), Cl (3), Br (4), I (5); dipp = 2,6-diisopropylphenyl phosphate] have been obtained by treating a methanol solution of zinc acetate with X-dippH2 and BIPYMO (in a 1:1:1 molar ratio) at ambient conditions. Framework phosphates 2-5 can also be obtained by treating the preformed D4R cubanes [Zn(X-dipp)(DMSO)]4 with required quantities of BIPYMO in methanol. Single-crystal X-ray diffraction studies reveal that these framework solids are two-dimensional (2D) networks as opposed to the diamondoid networks obtained when the parent unoxidized 4,4'-bipyridine is used as the linker (Inorg. Chem. 2014, 53, 8959). The two types of voids (viz., smaller intra-D4R and larger inter-D4R) present in these framework solids can be utilized for different types of encapsulation processes. For example, the in situ generated 2D framework 2 encapsulates fluoride ions accompanied by a change in the dimensionality of the framework to yield {[(nC4H9)4N][F@(Zn4(dipp)4(BIPYMO)2)]}n (6). The three-dimensional framework 6 represents the first structurally characterized example of a fluoride-ion-encapsulated polymeric coordination compound or a metal-organic framework. The possibility of utilizing inter-D4R voids as hosts for small organic molecules has been explored by treating in situ generated 2 with a series of organic molecules of appropriate size. Framework 2 has been found to be a selective host for benzil and not for other structurally similar molecules such as benzoquinone, benzidine, anthracene, naphthalene, α-pyridoin, etc. The benzil-occluded isolated framework [benzil@{Zn4(dipp)4(BIPYMO)2}]n (7) has been isolated as single crystals, and its crystal structure determination revealed the binding of benzil molecules to the framework through strong π-π interactions.

Synthesis of (cinnamate-zinc layered hydroxide) intercalation compound for sunscreen application

PubMed Central

2013-01-01

Background Zinc layered hydroxide (ZLH) intercalated with cinnamate, an anionic form of cinnamic acid (CA), an efficient UVA and UVB absorber, have been synthesized by direct method using zinc oxide (ZnO) and cinnamic acid as the precursor. Results The resulting obtained intercalation compound, ZCA, showed a basal spacing of 23.9 Å as a result of cinnamate intercalated in a bilayer arrangement between the interlayer spaces of ZLH with estimated percentage loading of cinnamate of about 40.4 % w/w. The UV–vis absorption spectrum of the intercalation compound showed excellent UVA and UVB absorption ability. Retention of cinnamate in ZLH interlayers was tested against media usually came across with sunscreen usage to show low release over an extended period of time. MTT assay of the intercalation compound on human dermal fibroblast (HDF) cells showed cytotoxicity of ZCA to be concentration dependent and is overall less toxic than its precursor, ZnO. Conclusions (Cinnamate-zinc layered hydroxide) intercalation compound is suitable to be used as a safe and effective sunscreen with long UV protection effect. PMID:23383738

Habit modification of bis-thiourea zinc chloride (ZTC) semi organic crystals by impurities

NASA Astrophysics Data System (ADS)

Ruby Nirmala, L.; Thomas Joseph Prakash, J.

2013-06-01

Single crystals of bis-thiourea zinc chloride (ZTC) doped with metal ion (Li+) possess excellent nonlinear optical properties. These crystals were grown by slow evaporation solution growth technique. The effect of Li+ dopant on the growth and properties of ZTC single crystal were investigated and reported. The grown crystals were crystallized in orthorhombic structure with non-centro symmetric space group Pn21a through the parent compound. The amount of dopant incorporated in the parent crystal was revealed by the inductively coupled plasma (ICP-OES) studies. The FT-IR spectroscopy study was done for finding and confirming the functional groups present in the compound. The UV-Visible spectral study was carried out to find the optical behavior and transparency nature of the grown crystal. TG/DTA measurements and Vickers microhardness measurements were traced to find out the thermal and mechanical stability of the grown crystals respectively. Using Nd:YAG laser, the Second harmonic generation (SHG) for the grown crystals were confirmed.

Habit modification of bis-thiourea zinc chloride (ZTC) semi organic crystals by impurities.

PubMed

Ruby Nirmala, L; Thomas Joseph Prakash, J

2013-06-01

Single crystals of bis-thiourea zinc chloride (ZTC) doped with metal ion (Li(+)) possess excellent nonlinear optical properties. These crystals were grown by slow evaporation solution growth technique. The effect of Li(+) dopant on the growth and properties of ZTC single crystal were investigated and reported. The grown crystals were crystallized in orthorhombic structure with non-centro symmetric space group Pn21a through the parent compound. The amount of dopant incorporated in the parent crystal was revealed by the inductively coupled plasma (ICP-OES) studies. The FT-IR spectroscopy study was done for finding and confirming the functional groups present in the compound. The UV-Visible spectral study was carried out to find the optical behavior and transparency nature of the grown crystal. TG/DTA measurements and Vickers microhardness measurements were traced to find out the thermal and mechanical stability of the grown crystals respectively. Using Nd:YAG laser, the Second harmonic generation (SHG) for the grown crystals were confirmed. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecular Speciation of Trace Metal Organic Complexes in the Pacific Ocean

NASA Astrophysics Data System (ADS)

Repeta, D.; Boiteau, R. M.; Bundy, R. M.; Babcock-Adams, L.

2017-12-01

Microbial production across approximately one third of the surface ocean is limited by extraordinarily low (picomolar) concentrations of dissolved iron, essentially all of which is complexed to strong organic ligands of unknown composition. Other biologically important trace metals (cobalt, copper, zinc, nickel) are also complexed to strong organic ligands, which again have not been extensively characterized. Nevertheless, organic ligands exert a strong influence on metal bioavailability and toxicity. For example, amendment experiments using commercially available siderophores, organic compounds synthesized by microbes to facilitate iron uptake, show these ligands can both facilitate or impede iron uptake depending on the siderophore composition and available uptake pathways. Over the past few years we have developed analytical techniques using high pressure liquid chromatography interfaced with inductively coupled plasma and electrospray ionization mass spectrometry to identify and quantify trace metal organic complexes in laboratory cultures of marine microbes and in seawater. We found siderophores to be widely distributed in the ocean, particularly in regions characterized by low iron concentrations. We also find chemically distinct complexes of copper, zinc, colbalt and nickel that we have yet to fully characterize. We will discuss some of our recent work on trace metal organic speciation in seawater and laboratory cultures, and outline future efforts to better understand the microbial cycling of trace metal organic complexes in the sea.

Electrocatalytic Zinc Composites as the Efficient Counter Electrodes of Dye-Sensitized Solar Cells: Study on the Electrochemical Performances and Density Functional Theory Calculations.

PubMed

Li, Chun-Ting; Chang, Hung-Yu; Li, Yu-Yan; Huang, Yi-June; Tsai, Yu-Lin; Vittal, R; Sheng, Yu-Jane; Ho, Kuo-Chuan

2015-12-30

Highly efficient zinc compounds (Zn3N2, ZnO, ZnS, and ZnSe) have been investigated as low-cost electrocatalysts for the counter electrodes (CE) of dye-sensitized solar cells (DSSCs). Among them, Zn3N2 and ZnSe are introduced for the first time in DSSCs. The zinc compounds were separately mixed with a conducting binder, poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) ( PSS), and thereby four composite films of Zn3N2/PEDOT:PSS, ZnO/PEDOT:PSS, ZnS/PEDOT:PSS, and ZnSe/ PSS were coated on the tin-doped indium oxide (ITO) substrates through a simple drop-coating process. In the composite film, nanoparticles of the zinc compound form active sites for the electrocatalytic reduction of triiodide ions, and PSS provides a continuous conductive matrix for fast electron transfer. By varying the weight percentage (5-20 wt %) of a zinc compound with respect to the weight of the PSS, the optimized concentration of a zinc compound was found to be 10 wt % in all four cases, based on the photovoltaic performances of the corresponding DSSCs. At this concentration (10 wt %), the composites films with Zn3N2 (Zn3N2-10), ZnO (ZnO-10), ZnS (ZnS-10), and ZnSe (ZnSe-10) rendered, for their DSSCs, power conversion efficiencies (η) of 8.73%, 7.54%, 7.40%, and 8.13%, respectively. The difference in the power conversion efficiency is explained based on the electrocatalytic abilities of those composite films as determined by cyclic voltammetry (CV), Tafel polarization plots, and electrochemical impedance spectroscopy (EIS) techniques. The energy band gaps of the zinc compounds, obtained by density functional theory (DFT) calculations, were used to explain the electrocatalytic behaviors of the compounds. Among all the zinc-based composites, the one with Zn3N2-10 showed the best electrocatalytic ability and thereby rendered for its DSSC the highest η of 8.73%, which is even higher than that of the cell with the traditional Pt CE (8.50%). Therefore, Zn3N2 can be considered as a promising inexpensive electrocatalyst to replace the rare and expensive Pt.

Ultrasound-assisted synthesis of nano-structured Zinc(II)-based metal-organic frameworks as precursors for the synthesis of ZnO nano-structures.

PubMed

Bigdeli, Fahime; Ghasempour, Hosein; Azhdari Tehrani, Alireza; Morsali, Ali; Hosseini-Monfared, Hassan

2017-07-01

A 3D, porous Zn(II)-based metal-organic framework {[Zn 2 (oba) 2 (4-bpmn)]·(DMF) 1.5 } n (TMU-21), (4-bpmn=N,N'-Bis-pyridin-4-ylmethylene-naphtalene-1,5-diamine, H 2 oba=4,4'-oxybis(benzoic acid)) with nano-rods morphology under ultrasonic irradiation at ambient temperature and atmospheric pressure was prepared and characterized by scanning electron microscopy. Sonication time and concentration of initial reagents effects on the size and morphology of nano-structured MOFs were studied. Also {[Zn 2 (oba) 2 (4-bpmn)] (TMU-21) and {[Zn 2 (oba) 2 (4-bpmb)] (TMU-6), 4-bpmb=N,N'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) were easily prepared by mechanochemical synthesis. Nanostructures of Zinc(II) oxide were obtained by calcination of these compounds and their de-solvated analogue as activated MOFs, at 550°C under air atmosphere. As a result of that, different Nanostructures of Zinc(II) oxide were obtained. The ZnO nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrothermal synthesis of zinc(II)-phosphonate coordination polymers with different dimensionality (0D, 2D, 3D) and dimensionality change in the solid phase (0D→3D) induced by temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernández-Zapico, Eva; Montejo-Bernardo, Jose; Fernández-González, Alfonso

2015-05-15

Three new zinc(II) coordination polymers, [Zn(HO{sub 3}PCH{sub 2}CH{sub 2}COO)(C{sub 12}H{sub 8}N{sub 2})(H{sub 2}O)] (1), [Zn{sub 3}(O{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(C{sub 12}H{sub 8}N{sub 2})](H{sub 2}O){sub 3.40} (2) and [Zn{sub 5}(HO{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(O{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(C{sub 12}H{sub 8}N{sub 2}){sub 4}](H{sub 2}O){sub 0.32} (3), with different structural dimensionality (0D, 2D and 3D, respectively) have been prepared by hydrothermal synthesis, and their structures were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system (P2{sub 1}/c) forming discrete dimeric units bonded through H-bonds, while compounds 2 and 3 crystallize in the triclinic (P−1) and the monoclinic (C2/c) systems, respectively.more » Compound 3, showing three different coordination numbers (4, 5 and 6) for the zinc atoms, has also been obtained by thermal treatment of 1 (probed by high-temperature XRPD experiments). The crystalline features of these compounds, related to the coordination environments for the zinc atoms in each structure, provoke the increase of the relative fluorescence for 2 and 3, compared to the free phenanthroline. Thermal analysis (TG and DSC) and XPS studies have been also carried out for all compounds. - Graphical abstract: Three new coordination compounds of zinc with 2-carboxyethylphosphonic acid (H{sub 2}PPA) and phenanthroline have been obtained by hydrothermal synthesis. The crystalline structure depends on the different coordination environments of the zinc atoms (see two comparative Zn{sub 6}-moieties). The influence of the different coordination modes of H{sub 2}PPA with the central atom in all structures have been studied, being found new coordination modes for this ligand. Several compounds show a significant increase in relative fluorescence with respect to the free phenanthroline. - Highlights: • Compounds have been obtained modifying the reaction time and the rate of reagents. • Dimensionality and crystalline structure is a function of the zinc environments. • New coordination modes for 2-carboxyethylphosphonic acid are reported. • 3D-compound presents three different coordination environments for the zinc atoms. • Fluorescence properties are related to the structural dimensionality.« less

Speciation analysis and bioaccessibility evaluation of trace elements in goji berries (Lycium Barbarum, L.).

PubMed

Wojcieszek, Justyna; Kwiatkowski, Piotr; Ruzik, Lena

2017-04-07

Goji berries (Lycium Barbarum, L.) are known for their nutritional potential as a great source of trace metals (e.g., copper, zinc and manganese) which are present in the form of highly bioaccessible compounds. In order to assess the bioaccessibility of trace elements and to identify compounds responsible for better bioaccessibility of copper and zinc, an in vitro simulation of gastrointestinal digestion was used in this study. The total content of trace metals was evaluated using sample digestion followed by inductively coupled plasma mass spectrometry. Bioaccessibility of trace elements was estimated by size exclusion chromatography coupled to inductively coupled plasma mass spectrometry. These analytical methods were used to analyse samples of goji berries to determine the highest amount of elements. For total trace metal content in goji berries, Zn had the highest level of the three studied (10.6μgg -1 ), while the total content of manganese and copper was 9.9μgg -1 and 6.1μgg -1 , respectively. Additionally, the analysed metals were found to be highly bioaccessible to the human body (about 56% for Mn, 72% for Cu and 64% for Zn in the gastric extract and approximately 35% for Mn, 23% for Cu and 31% for Zn in the case of gastrointestinal extract). To obtain information about metal complexes present in goji berries, extraction treatment using different solutions (ionic liquid, HEPES, SDS, Tris-HCl, ammonium acetate, water) was performed. Enzymatic treatment using pectinase and hemicellulase was also checked. Extracts of berries were analysed by SEC-ICP-MS and μHPLC-ESI-MS/MS techniques. The ionic liquid and pectinase extraction helped efficiently extract copper (seven compounds) and zinc (four compounds) complexes. Compounds identified in goji berries are most likely to be responsible for better bioaccessibility of those elements to the human organism. Copyright © 2017 Elsevier B.V. All rights reserved.

Photoswitching in azobenzene self-assembled monolayers capped on zinc oxide: nanodots vs nanorods.

PubMed

Shah, Syed Mujtaba; Martini, Cyril; Ackermann, Jörg; Fages, Frédéric

2012-02-01

We report the synthesis and spectroscopic characterization of nanohybrid structures consisting of an azobenzene compound grafted on the surface of zinc oxide nanoparticles. Characteristic bathochromic shifts indicate that the azobenzene photochromic molecules self-assemble onto the surface of the nanocrystals. The extent of packing is dependent on the shape of the nanoparticle. ZnO nanorods, with flat facets, enable a tighter organization of the molecules in the self-assembled monolayer than in the case of nanodots that display a more curvated shape. Consistently, the efficiency of photochromic switching of the self-assembled monolayer on ZnO nanoparticles is also shown to be strongly affected by nanoparticle shape. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of Leachate from Crumb Rubber and Zinc in Green Roofs on the Survival, Growth, and Resistance Characteristics of Salmonella enterica subsp. enterica Serovar Typhimurium

PubMed Central

Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H.

2014-01-01

The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain. PMID:24584242

Reconnaissance of chemical and physical characteristics of selected bottom sediments of the Caloosahatchee River and estuary, tributaries, and contiguous bays, Lee County, Florida, July 20-30, 1998

USGS Publications Warehouse

Fernandez, Mario; Marot, M.E.; Holmes, C.W.

1999-01-01

This report summarizes a reconnaissance study, conducted July 20-30, 1998, of chemical and physical characteristics of recently deposited bottom sediments in the Caloosahatchee River and Estuary. Recently deposited sediments were identified using an isotopic chronometer, Beryllium-7 (7Be), a short-lived radioisotope. Fifty-nine sites were sampled in an area that encompasses the Caloosahatchee River (River) about three miles upstream from the Franklin Lock (S-79), the entire tidally affected length of the river (estuary), and the contiguous water bodies of Matlacha Pass, San Carlos Bay, Estero Bay, Tarpon Bay, and Pine Island Sound in Lee County, Florida. Bottom sediments were sampled for 7Be at 59 sites. From the results of the 7Be analysis, 30 sites were selected for physical and chemical analysis. Sediments were analyzed for particle size, total organic carbon (TOC), trace elements, and toxic organic compounds, using semiquantitative methods for trace elements and organic compounds. The semiquantitative scans of trace elements indicated that cadmium, copper, lead, and zinc concentrations, when normalized to aluminum, were above the natural background range at 24 of 30 sites. Particle size and TOC were used to characterize sediment deposition patterns and organic content. Pesticides, polychlorinated biphenyls (PCBs), and carcinogenic polycyclic aromatic hydrocarbons (CaPAHs) were determined at 30 sites using immunoassay analysis. The semiquantitative immunoassay analyses of toxic organic compounds indicated that all of the samples contained DDT, cyclodienes as chlordane (pesticides), and CaPAHs. PCBs were not detected. Based on analyses of the 30 sites, sediments at 10 of these sites were analyzed for selected trace elements and toxic organic compounds, including pesticides, PCBs, and PAHs, using quantitative laboratory procedures. No arsenic or cadmium was detected. Zinc was detected at two sites with concentrations greater than the lower limit of the range of sediment contaminant concentrations that are usually or always associated with adverse effects (Florida Department of Environmental Protection's Sediment Quality Assessment Guidelines). Organochlorine pesticides were detected at four sites at concentrations below the reporting limits; there were no organophosphorus pesticides or PCBs detected. PAHs were detected at eight sites; however, only four sites had concentrations above the reporting limit.

Multi-modular, tris(triphenylamine) zinc porphyrin-zinc phthalocyanine-fullerene conjugate as a broadband capturing, charge stabilizing, photosynthetic 'antenna-reaction center' mimic.

PubMed

Kc, Chandra B; Lim, Gary N; D'Souza, Francis

2015-04-21

A broadband capturing, charge stabilizing, photosynthetic antenna-reaction center model compound has been newly synthesized and characterized. The model compound is comprised of a zinc porphyrin covalently linked to three units of triphenylamine entities and a zinc phthalocyanine entity. The absorption and fluorescence spectra of zinc porphyrin complemented that of zinc phthalocyanine offering broadband coverage. Stepwise energy transfer from singlet excited triphenylamine to zinc porphyrin, and singlet excited zinc porphyrin to zinc phthalocyanine (kENT ∼ 10(11) s(-1)) was established from spectroscopic and time-resolved transient absorption techniques. Next, an electron acceptor, fullerene was introduced via metal-ligand axial coordination to both zinc porphyrin and zinc phthalocyanine centers, and they were characterized by spectroscopic and electrochemical techniques. An association constant of 4.9 × 10(4) M(-1) for phenylimidazole functionalized fullerene binding to zinc porphyrin, and 5.1 × 10(4) M(-1) for it binding to zinc phthalocyanine was obtained. An energy level diagram for the occurrence of different photochemical events within the multi-modular donor-acceptor conjugate was established from spectral and electrochemical data. Unlike the previous zinc porphyrin-zinc phthalocyanine-fullerene conjugates, the newly assembled donor-acceptor conjugate has been shown to undergo the much anticipated initial charge separation from singlet excited zinc porphyrin to the coordinated fullerene followed by a hole shift process to zinc phthalocyanine resulting in a long-lived charge separated state as revealed by femto- and nanosecond transient absorption spectroscopic techniques. The lifetime of the final charge separated state was about 100 ns.

Oriented nanometric aggregates of partially inverted zinc ferrite: One-step processing and tunable high-frequency magnetic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sai, Ranajit, E-mail: ranajit@ecei.tohoku.ac.jp; Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore; Endo, Yasushi

2015-05-07

In this work, it is demonstrated that the in situ growth of oriented nanometric aggregates of partially inverted zinc ferrite can potentially pave a way to alter and tune magnetocrystalline anisotropy that, in turn, dictates ferromagnetic resonance frequency (f{sub FMR}) by inducing strain due to aggregation. Furthermore, the influence of interparticle interaction on magnetic properties of the aggregates is investigated. Mono-dispersed zinc ferrite nanoparticles (<5 nm) with various degrees of aggregation were prepared through decomposition of metal-organic compounds of zinc (II) and iron (III) in an alcoholic solution under controlled microwave irradiation, below 200 °C. The nanocrystallites were found to possess highmore » degree of inversion (>0.5). With increasing order of aggregation in the samples, saturation magnetization (at 5 K) is found to decrease from 38 emu/g to 24 emu/g, while coercivity is found to increase gradually by up to 100% (525 Oe to 1040 Oe). Anisotropy-mediated shift of f{sub FMR} has also been measured and discussed. In essence, the result exhibits an easy way to control the magnetic characteristics of nanocrystalline zinc ferrite, boosted with significant degree of inversion, at GHz frequencies.« less

Chronic Exposure to Zinc Chromate Induces Centrosome Amplification and Spindle Assembly Checkpoint Bypass in Human Lung Fibroblasts

PubMed Central

Holmes, Amie L.; Wise, Sandra S.; Pelsue, Stephen C.; Aboueissa, AbouEl-Makarim; Lingle, Wilma; Salisbury, Jeffery; Gallagher, Jamie; Wise, John Pierce

2010-01-01

Hexavalent chromium (Cr(VI)) compounds are known human lung carcinogens. Solubility plays an important role in its carcinogenicity with the particulate or insoluble form being the most potent. Of the particulate Cr(VI) compounds, zinc chromate appears to be the most potent carcinogen, however, very few studies have investigated its carcinogenic mechanism. In this study, we investigated the ability of chronic exposure to zinc chromate to induce numerical chromosome instability. We found no increase in aneuploidy after a 24 hour exposure to zinc chromate, but with more chronic exposures, zinc chromate induced concentration- and time-dependent increases in aneuploidy in the form of hypodiploidy, hyperdiploidy and tetraploidy. Zinc chromate also induced centrosome amplification in a concentration- and time-dependent manner in both interphase and mitotic cells after chronic exposure, producing cells with centriolar defects. Further, chronic exposure to zinc chromate induced concentration- and time-dependent increases in spindle assembly checkpoint bypass with increases in centromere spreading, premature centromere division and premature anaphase. Lastly, we found that chronic exposure to zinc chromate induced a G2 arrest. All together, these data indicate that zinc chromate can induce chromosome instability after prolonged exposures. PMID:20030412

Guest-induced emergent properties in Metal–Organic Frameworks

DOE PAGES

Allendorf, Mark D.; Foster, Michael E.; Léonard, François; ...

2015-03-19

Metal–Organic frameworks (MOFs) are crystalline nanoporous materials comprised of organic electron donors linked to metal ions by strong coordination bonds. Applications such as gas storage and separations are currently receiving considerable attention, but if the unique properties of MOFs could be extended to electronics, magnetics, and photonics, the impact on material science would greatly increase. Recently, we obtained “emergent properties,” such as electronic conductivity and energy transfer, by infiltrating MOF pores with “guest” molecules that interact with the framework electronic structure. In this Perspective, we define a path to emergent properties based on the Guest@MOF concept, using zinc-carboxylate and copper-paddlewheelmore » MOFs for illustration. Energy transfer and light harvesting are discussed for zinc carboxylate frameworks infiltrated with triplet-scavenging organometallic compounds and thiophene- and fullerene-infiltrated MOF-177. In addition, we discuss the mechanism of charge transport in TCNQ-infiltrated HKUST-1, the first MOF with electrical conductivity approaching conducting organic polymers. Lastly, these examples show that guest molecules in MOF pores should be considered not merely as impurities or analytes to be sensed but also as an important aspect of rational design.« less

Bulk functionalization of graphene using diazonium compounds and amide reaction

NASA Astrophysics Data System (ADS)

Peng, Chang; Xiong, Yuzi; Liu, Zhibo; Zhang, Fan; Ou, Encai; Qian, Jiangtao; Xiong, Yuanqin; Xu, Weijian

2013-09-01

An efficient and convenient method is applied to introduce varieties of simple functionalities onto the graphene surface for the bulk preparation, which begins with pristine graphite that does not require initial oxidative damage of the graphene basal planes. Diazonium compounds functionalized reaction is demonstrated and it successfully prevented the aggregation of graphene for which providing solubility in high polar organic media or even in volatile solvents such as ethanol and acetone. This approach is complemented by the phenyl carboxylic diazonium salt functionalized graphene (PCFG) attachment of a symmetrically substituted zinc phthalocyanine (PCFG-Pc) using the amide reaction, which is used for the covalent introduction of a complex phthalocyanine molecule.

Selection of organic acid leaching reagent for recovery of zinc and manganese from zinc-carbon and alkaline spent batteries

NASA Astrophysics Data System (ADS)

Yuliusman; Amiliana, R. A.; Wulandari, P. T.; Ramadhan, I. T.; Kusumadewi, F. A.

2018-03-01

Zinc-carbon and alkaline batteries are often used in electronic equipment that requires small quantities of power. The waste from these batteries contains valuable metals, such as zinc and manganese, that are needed in many industries and can pollute the environment if not treated properly. This paper concerns the recovery of zinc and manganese metals from zinc-carbon and alkaline spent batteries with leaching method and using organic acid as the environmental friendly leaching reagent. Three different organic acids, namely citric acid, malic acid and aspartic acid, were used as leaching reagents and compared with sulfuric acid as non-organic acid reagents that often used for leaching. The presence of hydrogen peroxide as manganese reducers was investigated for both organic and non-organic leaching reagents. The result showed that citric acid can recover 64.37% Zinc and 51.32% Manganese, while malic acid and aspartic acid could recover less than these. Hydrogen peroxide gave the significant effect for leaching manganese with non-organic acid, but not with organic acid.

Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

PubMed

Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

2013-01-01

The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

Development of acute and chronic sediment bioassays with the harpacticoid copepod Quinquelaophonte sp.

PubMed

Stringer, Tristan J; Glover, Chris N; Keesing, Vaughan; Northcott, Grant L; Gaw, Sally; Tremblay, Louis A

2014-01-01

Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints. Spiked sediments were used to expose Quinquelaophonte sp. to three reference compounds representing important categories of estuarine chemical stressors: zinc (a metal), atrazine (a pesticide), and phenanthrene (a polycyclic aromatic hydrocarbon). Acute-to-chronic ratios (ACR) were used to further characterise species responses. Acute sediment (sandy and low total organic content) 96 h EC50 values for the sublethal inhibition of mobility for zinc, atrazine and phenanthrene were 137, 5.4, and 2.6 µg/g, respectively. The chronic EC50 values for inhibition of reproduction (total offspring) were 54.5, 0.0083, and 0.067 µg/g for zinc, atrazine, and phenanthrene, respectively. For phenanthrene, a potentially novel mode of action was identified on reproduction. Quinquelaophonte sp. was found to be more sensitive than several other estuarine species indicating choice of test organism is important to characterising the effects of environmentally relevant levels of contamination. The bioassay sediment results demonstrate the sensitivity and suitability of Quinquelaophonte sp. as a tool for the assessment use of estuarine health. © 2013 Published by Elsevier Inc.

Low-Resistivity Zinc Selenide for Heterojunctions

NASA Technical Reports Server (NTRS)

Stirn, R. J.

1986-01-01

Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

Hydrologic and water-quality data from Mountain Island Lake, North Carolina, 1994-97

USGS Publications Warehouse

Sarver, K.M.; Steiner, B.C.

1998-01-01

Continuous-record water-level gages were established at three sites on Mountain Island Lake and one site downstream from Mountain Island Dam. The water level of Mountain Island Lake is controlled by Duke Power Company releases at Cowans Ford Dam (upstream) and Mountain Island Dam (downstream). Water levels on Mountain Island Lake measured just downstream from Cowans Ford Dam fluctuated 11.15 feet during the study. Water levels just upstream from the Mountain Island Lake forebay fluctuated 6.72 feet during the study. About 3 miles downstream from Mountain Island Dam, water levels fluctuated 5.31 feet. Sampling locations included 14 sites in Mountain Island Lake, plus one downstream river site. At three sites, automated instruments recorded water temperature, dissolved-oxygen concentration, and specific conductance at 15-minute intervals throughout the study. Water temperatures recorded continuously during the study ranged from 4.2 to 35.2 degrees Celsius, and dissolved-oxygen concentrations ranged from 2.1 to 11.8 milligrams per liter. Dissolved-oxygen concentrations generally were inversely related to water temperature, with lowest dissolved-oxygen concentrations typically recorded in the summer. Specific conductance values recorded continuously during the study ranged from 33 to 89 microsiemens per centimeter; however, mean monthly values were fairly consistent throughout the study at all sites (50 to 61 microsiemens per centimeter). In addition, vertical profiles of water temperature, dissolved-oxygen concentration, specific conductance, and pH were measured at all sampling locations during 24 site visits. Water-quality constituent concentrations were determined for seven reservoir sites and the downstream river site during 17 sampling trips. Water-quality samples were routinely analyzed for biochemical oxygen demand, fecal coliform bacteria, hardness, alkalinity, total and volatile suspended solids, nutrients, total organic carbon, chlorophyll, iron, calcium, and magnesium; the samples were analyzed less frequently for trace metals, volatile organic compounds, semivolatile organic compounds, and pesticides. Maximum dissolved nitrite plus nitrate concentrations determined during the study were 0.348 milligram per liter in the mainstem sites and 2.77 milligrams per liter in the coves. Maximum total phosphorus concentrations were 0.143 milligram per liter in the mainstem sites and 0.600 milligram per liter in the coves. Fecal coliform and chlorophyll a concentrations were less than or equal to 160 colonies per 100 milliliters and 13 micrograms per liter, respectively, in all samples. Trace metals detected in at least one sample included arsenic, chromium, copper, lead, nickel, zinc, and antimony. Concentrations of all trace metals (except zinc) were 5.0 micrograms per liter or less; the maximum zinc concentration was 80 micrograms per liter. One set of bottom material samples was collected from Gar Creek and McDowell Creek for chemical analysis and analyzed for nutrients, trace metals, organochlorine pesticides, and semivolatile organic compounds. The only organochlorine pesticide identified in either sample was p,p'-DDE at an estimated concentration of 0.8 microgram per kilogram. Twenty semivolatile organic compounds, mainly polyaromatic hydrocarbons and plasticizers, were identified.

Virtual screening using the ligand ZINC database for novel lipoxygenase-3 inhibitors.

PubMed

Monika; Kour, Janmeet; Singh, Kulwinder

2013-01-01

The leukotrienes constitute a group of arachidonic acid-derived compounds with biologic activities suggesting important roles in inflammation and immediate hypersensitivity. Epidermis-type lipoxygenase-3 (ALOXE3), a distinct subclass within the multigene family of mammalian lipoxygenases, is a novel isoenzyme involved in the metabolism of leukotrienes and plays a very important role in skin barrier functions. Lipoxygenase selective inhibitors such as azelastine and zileuton are currently used to reduce inflammatory response. Nausea, pharyngolaryngeal pain, headache, nasal burning and somnolence are the most frequently reported adverse effects of these drugs. Therefore, there is still a need to develop more potent lipoxygenase inhibitors. In this paper, we report the screening of various compounds from the ZINC database (contains over 21 million compounds) using the Molegro Virtual Docker software against the ALOXE3 protein. Screening was performed using molecular constraints tool to filter compounds with physico-chemical properties similar to the 1N8Q bound ligand protocatechuic acid. The analysis resulted in 4319 Lipinski compliant hits which are docked and scored to identify structurally novel ligands that make similar interactions to those of known ligands or may have different interactions with other parts of the binding site. Our screening approach identified four molecules ZINC84299674; ZINC76643455; ZINC84299122 & ZINC75626957 with MolDock score of -128.901, -120.22, -116.873 & - 102.116 kcal/mol, respectively. Their energy scores were better than the 1N8Q bound co-crystallized ligand protocatechuic acid (with MolDock score of -77.225 kcal/mol). All the ligands were docked within the binding pocket forming interactions with amino acid residues.

Leaching of zinc compound from rubber stoppers into the contents of automatic atropine injectors.

PubMed

Ellin, R I; Kaminskis, A; Zvirblis, P; Sultan, W E; Shutz, M B; Matthews, R

1985-07-01

This report describes how a material within the cartridge of an automatic injector contaminated its contents. On prolonged storage, a formulation that contained atropine produced lethality in mice. The toxic material originated from zinc compounds that were present in the rubber stopper and plunger of the container and that subsequently leached into the formulation. The contents of cartridges that contained greater than or equal to 0.75 mg/mL of solubilized zinc were lethal to at least 20% of the mice tested; those that contained 0.42 mg/mL showed no lethality. The problem resulted from the physicochemical properties of the rubber, not the concentration of zinc used in the vulcanization process.

Virtual screening using MTiOpenScreen and PyRx 0,8 revealed ZINC95486216 as a human acetylcholinesterase inhibitor candidate

NASA Astrophysics Data System (ADS)

Sulistyo Dwi K., P.; Arindra Trisna, W.; Vindri Catur P., W.; Wijayanti, Erna; Ichsan, Mochammad

2016-03-01

One of the efforts to prevent Alzheimer's disease becomes more severe is by inhibiting the activity of Human acetylcholinesterase enzyme (PDB ID: 4BDT). In this study, virtual screening againts 885 natural compounds from AfroDB has been done using MTIOpenScreen and this step has been successful in identifying ZINC15121024 (-12,9) and ZINC95486216 (-12,7) as the top rank compounds. This data then strengthened by the results of second docking step using Autodock software that has been integrated in PyRx 0.8 software. From this stage, ZINC95486216 (-11,3 kcal/mol) is a compound with the most negative binding affinity compared with four Alzheimer's drugs that have been officially used to date including Rivastigmine (-6,3 Kcal/mol), Donepenzil (-7.9 kcal/mol), Galantamine (-8.4 kcal/mol), and Huprine W (-7.3 kcal/mol). In addition, based on the results of the 2D and 3D visualization using LigPlus and PyMol softwares, respectively, known that the five compounds above are equally capable of binding to several amino acids (Trp 286, Phe295, and Tyr341) located in the active site of Human Acetylcholinesterase enzyme.

Two new three-dimensional zinc phosphites templated by piperazine: [H2pip][Zn3(HPO3)4(H2O)2] and K[H2pip]0.5[Zn3(HPO3)4

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Wang, Guo-Ming; Wang, Zong-Hua; Wang, Ying-Xia; Lin, Jian-Hua

2014-01-01

Two three-dimensional open-framework zinc phosphites with the same organically templated, [H2pip][Zn3(HPO3)4(H2O)2] (1) and K[H2pip]0.5[Zn3(HPO3)4] (2) (pip = piperazine), have been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Compound 1 consists of ZnO4 tetrahedra, [HPO3] pseudopyramids and [ZnO4(H2O)2] octahedra, which are linked through their vertexes to generate three-dimensional architecture with intersecting 8-membered channels along the [1 0 0], [0 0 1] and [1 0 1] directions. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and [HPO3] pseudopyramids, and exhibits (3,4)-connected inorganic framework with 8-, and 12-membered channels, in which the K+ and diprotonated H2pip2+ extra-framework cations reside, respectively. The coexistence of inorganic K+ and organic piperazine mixed templates in the structure is unique and, to the best of our knowledge, firstly observed in metal-phosphite materials. In addition, the participation of left-handed and right-handed helical chains in construction of the puckered 4.82 sheet structure in 2 is also noteworthy.

Effect of acetate and nitrate anions on the molecular structure of 3-(hydroxyimino)-2-butanone-2-(1H-benzimidazol-2-yl)hydrazone

NASA Astrophysics Data System (ADS)

Kamat, Vinayak; Naik, Krishna; Revankar, Vidyanand K.

2017-04-01

A novel Schiff base ligand 3-(hydroxyimino)-2-butanone-2-(1H-benzimidazol-2-yl)hydrazone has been synthesized by the condensation reaction of 2-Hydrazinobenzimidazole with diacetyl monoxime in presence of acetic acid catalyst. The ligand has crystallized as its acetate salt, due to the charge-assisted hydrogen bonding between protonated benzimidazole ring and acetate anion. Efforts to synthesize the zinc(II) complex of the title compound, has resulted in the formation of a nitrate salt of the ligand, instead of coordination complex of zinc(II). Acetate salt has crystallized in monoclinic P 21/n, while the nitrate salt has crystallized in a triclinic crystal system with P -1 space group. Hirshfeld surface analysis is presented for both of the crystal structures. Structures of synthesized molecules are even computationally optimized using DFT. A comparative structural approach between the synthesized molecules and DFT optimized structure of bare ligand without any counterions is analyzed in terms of bond parameters. Hydrogen bonding is explained keeping the anions as the central dogma. Mass fragmentation pattern of the organic molecule and comparative account of IR, 1H and 13C NMR chemical shifts are also presented. Compounds are screened for their antibacterial and antifungal potencies against few pathogenic microorganisms. The organic motif is found be an excellent antifungal agent.

Stable dimeric magnesium(I) compounds: from chemical landmarks to versatile reagents.

PubMed

Stasch, Andreas; Jones, Cameron

2011-06-07

The chemistry of the s-block metals is dominated by the +1 oxidation state for the Alkali metals (group 1) and the +2 oxidation state for the Alkaline Earth metals (group 2). In recent years, a series of stable dimeric magnesium(I) compounds has been prepared and their chemistry has started to develop. These complexes feature "deformable" Mg-Mg single bonds and are stabilised by sterically demanding and chelating anionic N-ligands that prevent their disproportionation. They have rapidly proven useful in organic and organometallic/inorganic reduction reactions as hydrocarbon soluble, stoichiometric, selective and safe reducing agents. The scope of this perspective focuses on stable molecular compounds of the general type LMgMgL and describes their synthesis, structures, theoretical and spectroscopic studies as well as their further chemistry. Also, comparisons are drawn with related complexes including magnesium(II) hydrides and dimeric zinc(I) compounds.

Extreme electronic modulation of the cofacial porphyrin structural motif.

PubMed

Fletcher, James T; Therien, Michael J

2002-04-24

The synthesis, electrochemistry, and optical spectroscopy of an extensive series of cofacial bis[(porphinato)zinc(II)] compounds are reported. These species were synthesized using sequential palladium-catalyzed cross-coupling and cobalt-mediated [2+2+2] cycloaddition reactions. This modular methodology enables facile control of the nature of macrocycle-to-macrocycle connectivity and allows unprecedented modulation of the redox properties of face-to-face porphyrin species. We report the synthesis of 5,6-bis[(5',5''-10',20'-bis[4-(3-methoxy-3-methylbutoxy)phenyl]porphinato)zinc(II)]indane (1), 5,6-bis[(2'-5',10',15',20'-tetraphenylporphinato)zinc(II)]indane (2), 5-([2'-5',10',15',20'-tetraphenylporphinato]zinc(II))-6-[(5"-10'',20''-bis[4-(3-methoxy-3-methylbutoxy)phenyl]porphinato)zinc(II)]indane (3), 5-([2'-5',10',15',20'-tetrakis(trifluoromethyl)porphinato]zinc(II))-6-[(5' '-10' ',20' '-bis[4-(3-methoxy-3-methylbutoxy)phenyl]porphinato)zinc(II)]indane (4), 5-(2'-5',10',15',20'-[tetrakis(trifluoromethyl)porphinato]zinc(II))-6-[(2''-5'',10'',15'',20''-tetraphenylporphinato)zinc(II)]indane (5), 5,6-bis([2'-5',15'-diphenyl-10',20'-(trifluoromethyl)porphinato]zinc(II))indane (6), and 5,6-bis([2'-5',10',15',20'-tetrakis(trifluoromethyl)porphinato]zinc(II))indane (7); 4-7 define the first examples of cofacial bis[(porphinato)metal] compounds in which sigma-electron-withdrawing perfluoroalkyl groups serve as macrocycle substituents, while 2, 6, and 7 constitute the first such structures that possess a beta-to-beta linkage topology. Cyclic voltammetric studies show that the electrochemically determined HOMO and LUMO energy levels of these cofacial bis(porphinato) complexes can be lowered by 780 and 945 mV, respectively, relative to the archetypal members of this class of compounds; importantly, these orbital energy levels can be modulated over well-defined increments throughout these wide potentiometric domains. Analyses of these cofacial bis[(porphinato)metal] potentiometric data, in terms of the absolute and relative frontier orbital energies of their constituent [porphinato]zinc(II) building blocks, as well as the nature of macrocycle-to-macrocycle connectivity, provide predictive electronic structural models that rationalize the redox behavior of these species.

The Decomposition of Zinc Carbonate: Using Stoichiometry to Choose between Chemical Formulas

ERIC Educational Resources Information Center

DeMeo, Stephen

2004-01-01

The existence of different stoichiometries in two basic zinc carbonates helps to explain their decomposition potential, and to select between the two compound formulas, which better describes zinc carbonate. The accuracy of the experiment makes it a viable means for students to perform various quantitative measurements.

Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico and Texas; organic compounds and trace elements in bed sediment and fish tissue, 1992-93

USGS Publications Warehouse

Carter, L.F.; Anderholm, S.K.

1997-01-01

The occurrence and distribution of contaminants in aquatic systems are major components of the National Water-Quality Assessment (NAWQA) Program. Bed-sediment samples were collected at 18 sites in the Rio Grande Valley study unit between September 1992 and March 1993 to characterize the geographic distribution of organic compounds, including chlorinated insecticides, polychlorinated biphenyls (PCB's), and other chlorinated hydrocarbons, and also trace elements. Two-millimeter-size- fraction sediment was analyzed for organic compounds and less than 63-micron-size-fraction sediment was analyzed for trace elements. Concentrations of p,p'-DDE were detected in 33 percent of the bed-sediment samples. With the exception of DDT-related compounds, no other organochlorine insecticides or polychlorinated biphenyls were detected in samples of bed sediment. Whole-body fish samples were collected at 11 of the bed- sediment sites and analyzed for organic compounds. Organic compounds were reported more frequently in samples of fish, and more types of organic compounds were found in whole-body fish samples than in bed-sediment samples. Concentrations of p,p'-DDE were detected in 91 percent of whole-body fish samples. Polychlorinated biphenyls, cis-chlordane, trans-chlordane, trans- nonachlor, and hexachlorobenzene were other organic compounds detected in whole-body samples of fish from at least one site. Because of the extent of mineralized areas in the Rio Grande Basin arsenic, cadmium, copper, lead, mercury, selenium, and zinc concentrations in bed-sediment samples could represent natural conditions at most sites. However, a combination of natural conditions and human activities appears to be associated with elevated trace-element concentrations in the bed-sediment sample from the site Rio Grande near Creede, Colorado, because this sample exceeded the background trace-element concentrations calculated for this study. Fish-liver samples were collected at 12 of the bed-sediment sites and analyzed for trace elements. Certain trace elements were detected at higher concentrations in fish-liver samples than in bed-sediment samples from the same site. Both bed-sediment and fish-tissue samples are necessary for a complete environmental assessment of the occurrence and distribution of trace elements.

Role of nutritional zinc in the prevention of osteoporosis.

PubMed

Yamaguchi, Masayoshi

2010-05-01

Zinc is known as an essential nutritional factor in the growth of the human and animals. Bone growth retardation is a common finding in various conditions associated with dietary zinc deficiency. Bone zinc content has been shown to decrease in aging, skeletal unloading, and postmenopausal conditions, suggesting its role in bone disorder. Zinc has been demonstrated to have a stimulatory effect on osteoblastic bone formation and mineralization; the metal directly activates aminoacyl-tRNA synthetase, a rate-limiting enzyme at translational process of protein synthesis, in the cells, and it stimulates cellular protein synthesis. Zinc has been shown to stimulate gene expression of the transcription factors runt-related transcription factor 2 (Runx2) that is related to differentiation into osteoblastic cells. Moreover, zinc has been shown to inhibit osteoclastic bone resorption due to inhibiting osteoclast-like cell formation from bone marrow cells and stimulating apoptotic cell death of mature osteoclasts. Zinc has a suppressive effect on the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-induced osteoclastogenesis. Zinc transporter has been shown to express in osteoblastic and osteoclastic cells. Zinc protein is involved in transcription. The intake of dietary zinc causes an increase in bone mass. beta-Alanyl-L: -histidinato zinc (AHZ) is a zinc compound, in which zinc is chelated to beta-alanyl-L: -histidine. The stimulatory effect of AHZ on bone formation is more intensive than that of zinc sulfate. Zinc acexamate has also been shown to have a potent-anabolic effect on bone. The oral administration of AHZ or zinc acexamate has the restorative effect on bone loss under various pathophysiologic conditions including aging, skeletal unloading, aluminum bone toxicity, calcium- and vitamin D-deficiency, adjuvant arthritis, estrogen deficiency, diabetes, and fracture healing. Zinc compounds may be designed as new supplementation factor in the prevention and therapy of osteoporosis.

Method of solubilizing phthalocyanines and metallophthalocyanines

DOEpatents

Rathke, Jerome W.; Chen, Michael J.; Fendrick, Carol M.

1997-11-04

A one-step method of manufacturing soluble phthalocyanines and metallophthalocyanines, like zinc phthalocyanine, by converting a phthalocyanine or a metallophthalocyanine to a trialkylsilyl-substituted derivative is disclosed. The phthalocyanine or metallophthalocyanine is converted to a soluble trialkylsilyl-substituted derivative by interacting the phthalocyanine or metallophthalocyanine with an active metal amide, like lithium 2,2,6,6-tetramethylpiperidide, and a halotrialkylsilane, like chlorotrimethylsilane, to provide a phthalocyanine compound, like phthalocyanine monomers, dimers or polymers, metalated or unmetalated, that are soluble in organic media.

Method of solubilizing phthalocyanines and metallophthalocyanines

DOEpatents

Rathke, Jerome W.; Chen, Michael J.; Fendrick, Carol M.

1997-01-01

A one-step method of manufacturing soluble phthalocyanines and metallophthalocyanines, like zinc phthalocyanine, by converting a phthalocyanine or a metallophthalocyanine to a trialkylsilyl-substituted derivative is disclosed. The phthalocyanine or metallophthalocyanine is converted to a soluble trialkylsilyl-substituted derivative by interacting the phthalocyanine or metallophthalocyanine with an active metal amide, like lithium 2,2,6,6-tetramethylpiperidide, and a halotrialkylsilane, like chlorotrimethylsilane, to provide a phthalocyanine compound, like phthalocyanine monomers, dimers or polymers, metalated or unmetalated, that are soluble in organic media.

Computational Study on New Natural Compound Inhibitors of Pyruvate Dehydrogenase Kinases

PubMed Central

Zhou, Xiaoli; Yu, Shanshan; Su, Jing; Sun, Liankun

2016-01-01

Pyruvate dehydrogenase kinases (PDKs) are key enzymes in glucose metabolism, negatively regulating pyruvate dehyrogenase complex (PDC) activity through phosphorylation. Inhibiting PDKs could upregulate PDC activity and drive cells into more aerobic metabolism. Therefore, PDKs are potential targets for metabolism related diseases, such as cancers and diabetes. In this study, a series of computer-aided virtual screening techniques were utilized to discover potential inhibitors of PDKs. Structure-based screening using Libdock was carried out following by ADME (adsorption, distribution, metabolism, excretion) and toxicity prediction. Molecular docking was used to analyze the binding mechanism between these compounds and PDKs. Molecular dynamic simulation was utilized to confirm the stability of potential compound binding. From the computational results, two novel natural coumarins compounds (ZINC12296427 and ZINC12389251) from the ZINC database were found binding to PDKs with favorable interaction energy and predicted to be non-toxic. Our study provide valuable information of PDK-coumarins binding mechanisms in PDK inhibitor-based drug discovery. PMID:26959013

Computational Study on New Natural Compound Inhibitors of Pyruvate Dehydrogenase Kinases.

PubMed

Zhou, Xiaoli; Yu, Shanshan; Su, Jing; Sun, Liankun

2016-03-04

Pyruvate dehydrogenase kinases (PDKs) are key enzymes in glucose metabolism, negatively regulating pyruvate dehyrogenase complex (PDC) activity through phosphorylation. Inhibiting PDKs could upregulate PDC activity and drive cells into more aerobic metabolism. Therefore, PDKs are potential targets for metabolism related diseases, such as cancers and diabetes. In this study, a series of computer-aided virtual screening techniques were utilized to discover potential inhibitors of PDKs. Structure-based screening using Libdock was carried out following by ADME (adsorption, distribution, metabolism, excretion) and toxicity prediction. Molecular docking was used to analyze the binding mechanism between these compounds and PDKs. Molecular dynamic simulation was utilized to confirm the stability of potential compound binding. From the computational results, two novel natural coumarins compounds (ZINC12296427 and ZINC12389251) from the ZINC database were found binding to PDKs with favorable interaction energy and predicted to be non-toxic. Our study provide valuable information of PDK-coumarins binding mechanisms in PDK inhibitor-based drug discovery.

Zinc oxyfluoride transparent conductor

DOEpatents

Gordon, Roy G.

1991-02-05

Transparent, electrically conductive and infrared-reflective films of zinc oxyfluoride are produced by chemical vapor deposition from vapor mixtures of zinc, oxygen and fluorine-containing compounds. The substitution of fluorine for some of the oxygen in zinc oxide results in dramatic increases in the electrical conductivity. For example, diethyl zinc, ethyl alcohol and hexafluoropropene vapors are reacted over a glass surface at 400.degree. C. to form a visibly transparent, electrically conductive, infrared reflective and ultraviolet absorptive film of zinc oxyfluoride. Such films are useful in liquid crystal display devices, solar cells, electrochromic absorbers and reflectors, energy-conserving heat mirrors, and antistatic coatings.

Metals, pesticides, and semivolatile organic compounds in sediment in Valley Forge National Historical Park, Montgomery County, Pennsylvania

USGS Publications Warehouse

Reif, Andrew G.; Sloto, Ronald A.

1997-01-01

The Schuylkill River flows through Valley Forge National Historical Park in Lower Providence and West Norriton Townships in Montgomery County, Pa. The concentration of selected metals, pesticides, semivolatile organic compounds, and total carbon in stream-bottom sediments from Valley Forge National Historical Park were determined for samples collected once at 12 sites in and around the Schuylkill River.Relatively low concentrations of arsenic, chromium, copper, and lead were detected in all samples. The concentrations of these metals are similar to concentrations in other stream-bottom sediment samples collected in the region. The concentrations of iron, manganese, and zinc were elevated in samples from four sites in the Schuylkill River, and the concentration of mercury was elevated in a sample from an impoundment along the river.The organophosphorus insecticide diazinon was detected in relatively low concentrations in half of the 12 samples analyzed. The organo-chlorine insecticide DDE was detected in all 12 samples analyzed; dieldrin was detected in 10 samples, chlordane, DDD, and DDT were detected in 9 samples, and heptachlor epoxide was detected in one sample. The concentrations of organo-chlorine and organophosphorus insecticides were relatively low and similar to concentrations in samples collected in the region.Detectable concentrations of 17 semivolatile organic compounds were measured in the 12 samples analyzed. The most commonly detected compounds were fluoranthene, phenanthrene, and pyrene. The maximum concentration detected was 4,800 micrograms per kilogram of phenanthrene. The highest concentrations of compounds were detected in Lamb Run, a small tributary to the Schuylkill River with headwaters in an industrial corporate center. The concentration of compounds in the Schuylkill River below Lamb Run is higher than the Schuylkill River above Lamb Run, indicating that sediment from Lamb Run is increasing the concentration of semivolatile organic compounds in sediment from the Schuylkill River. Concentrations of semivolatile organic compounds are lower in sediment from the Schuylkill River below Myer's Run than above Myer's Run because of the addition of relatively clean sediment from Myer's Run. Samples collected from the floodplain, impounding basin, and wetland along the Schuylkill River contained the lowest concen-trations of semivolatile organic compounds.Detectable concentrations of polychlorinated biphenyls (PCB's) were measured in 11 of the 12 samples analyzed. The maximum PCB concentration was 37 micrograms per kilogram. Sediment samples from Lamb Run contained the highest concentrations of semivolatile organic compounds and PCB's.

Copper(II) and zinc(II) dinuclear enzymes model compounds: The nature of the metal ion in the biological function

NASA Astrophysics Data System (ADS)

Ferraresso, L. G.; de Arruda, E. G. R.; de Moraes, T. P. L.; Fazzi, R. B.; Da Costa Ferreira, A. M.; Abbehausen, C.

2017-12-01

First series transition metals are used abundantly by nature to perform catalytic transformations of several substrates. Furthermore, the cooperative activity of two proximal metal ions is common and represents a highly efficient catalytic system in living organisms. In this work three dinuclear μ-phenolate bridged metal complexes were prepared with copper(II) and zinc(II), resulting in a ZnZn, CuCu and CuZn with the ligand 2-ethylaminodimethylamino phenol (saldman) as model compounds of superoxide dismutase (CuCu and CuZn) and metallo-β-lactamases (ZnZn). Metals are coordinated in a μ-phenolate bridged symmetric system. Cu(II) presents a more distorted structure, while zinc is very symmetric. For this reason, [CuCu(saldman)] shows higher water solubility and also higher lability of the bridge. The antioxidant and hydrolytic beta-lactamase-like activity of the complexes were evaluated. The lability of the bridge seems to be important for the antioxidant activity and is suggested to because of [CuCu(saldman)] presents a lower antioxidant capacity than [CuZn(saldman)], which showed to present a more stable bridge in solution. The hydrolytic activity of the bimetallic complexes was assayed using nitrocefin as substrate and showed [ZnZn(saldman)] as a better catalyst than the Cu(II) analog. The series demonstrates the importance of the nature of the metal center for the biological function and how the reactivity of the model complex can be modulated by coordination chemistry.

Effects of surface applications of biosolids on groundwater quality and trace-element concentrations in crops near Deer Trail, Colorado, 2004-2010

USGS Publications Warehouse

Yager, Tracy J.B.; Crock, James G.; Smith, David B.; Furlong, Edward T.; Hageman, Philip L.; Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.

2013-01-01

The U.S. Geological Survey (USGS), in cooperation with Metro Wastewater Reclamation District (Metro District), studied biosolids composition and the effects of biosolids applications on groundwater quality and trace-element concentrations in crops of the Metro District properties near Deer Trail, Colorado, during 2004 through 2010. Priority parameters for each monitoring component included the nine trace elements regulated by Colorado for biosolids (arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc); other constituents also were analyzed. All concentrations for the priority parameters in monthly biosolids samples were less than Colorado regulatory limits, and the concentrations were relatively consistent. Biosolids likely were the largest source of nitrogen and phosphorus on the Metro District properties. Plutonium isotopes were not detected in the biosolids, but many organic wastewater compounds (organic wastewater compounds: wastewater indicators, pharmaceuticals, and hormones) were detected in substantial concentrations relative to minimum reporting levels and various surface-water concentrations. Bismuth, copper, mercury, nitrogen, phosphorus, silver, biogenic sterols, detergent degradates, disinfectants, fire retardants, fragrances, pharmaceuticals, and plasticizers would be the most likely biosolids signature to indicate the presence of Metro District biosolids in soil or streambed sediment from the study area. Antimony, cadmium, cobalt, copper, molybdenum, nickel, nitrogen, phosphorus, selenium, tungsten, vanadium, zinc, detergent degradates, disinfectants, fire retardants, fragrances, pharmaceuticals or their degradates, and plasticizers would be the most likely biosolids signature for groundwater and surface water in the study area. More biosolids-signature components detected and larger concentration differences from untreated materials, baseline, and blank samples indicate more evidence of biosolids presence or effects. Although the inorganic constituent concentrations were relatively large in samples from one monitoring well, the concentrations of organic wastewater compounds in groundwater samples were not correspondingly large. Concentrations of organic wastewater compounds in the groundwater samples from all five monitoring wells were less than the minimum reporting levels with only a few detections. Some of the organic wastewater compounds detected could have anthropogenic sources that are not biosolids. Concentrations of priority parameters in groundwater varied spatially and temporally but generally were less than Colorado regulatory limits. Concentrations of dissolved nitrate, arsenic, and selenium, in addition to chloride, sulfate, total dissolved solids, boron, iron, manganese, and uranium, in samples from some wells exceeded the Colorado standards. Concentrations of dissolved nitrate (three wells), molybdenum (one well), selenium (two wells), and uranium (one well) in shallow groundwater had significant (alpha = 0.05) upward trends in some parts of the study area. The biosolids-signature results indicate that the aquifers intercepted by the five routinely sampled wells likely have received some recharge through treated (biosolids-applied) fields or biosolids-affected ponds. Adverse effects from this biosolids-related recharge range from few (if any) at one well to large and significantly (alpha = 0.05) increasing nitrate concentrations at another well. A statistical evaluation of five paired wheat-grain samples from treated (biosolids-applied) fields and untreated (control) fields did not indicate any evidence that biosolids applications significantly (alpha = 0.05 or 0.10) increased concentration of any of these constituents in wheat grain. The wheat-grain concentrations from this study were similar to those from other studies for fields in North America where no biosolids were applied. The data for the limited crop samples indicate that biosolids applications are not increasing the concentrations of arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, sulfur, and zinc in mature wheat grain from the study area.

Low-Temperature Photochemically Activated Amorphous Indium-Gallium-Zinc Oxide for Highly Stable Room-Temperature Gas Sensors.

PubMed

Jaisutti, Rawat; Kim, Jaeyoung; Park, Sung Kyu; Kim, Yong-Hoon

2016-08-10

We report on highly stable amorphous indium-gallium-zinc oxide (IGZO) gas sensors for ultraviolet (UV)-activated room-temperature detection of volatile organic compounds (VOCs). The IGZO sensors fabricated by a low-temperature photochemical activation process and exhibiting two orders higher photocurrent compared to conventional zinc oxide sensors, allowed high gas sensitivity against various VOCs even at room temperature. From a systematic analysis, it was found that by increasing the UV intensity, the gas sensitivity, response time, and recovery behavior of an IGZO sensor were strongly enhanced. In particular, under an UV intensity of 30 mW cm(-2), the IGZO sensor exhibited gas sensitivity, response time and recovery time of 37%, 37 and 53 s, respectively, against 750 ppm concentration of acetone gas. Moreover, the IGZO gas sensor had an excellent long-term stability showing around 6% variation in gas sensitivity over 70 days. These results strongly support a conclusion that a low-temperature solution-processed amorphous IGZO film can serve as a good candidate for room-temperature VOCs sensors for emerging wearable electronics.

Unprecedented chemosensing behavior of novel tetra-substituted benzimidazole zinc(II) phthalocynine for selective detection of Bi3 + ion: Synthesis, characterization and ROS generation

NASA Astrophysics Data System (ADS)

Ullah, Azeem; Shah, Faheem; Khan, Imran; Anwar, Muhammad; Shah, Kiramat; Muhammad, Munira Taj; Ahmad, Farid

2018-03-01

In this work, synthesis of novel symmetrical 4-(2-bromo-4-(5-bromo-1H-benzo[d] imidazol-2-yl) phenoxy) tetra substituted zinc phthalocyanine has been reported. The novel benzimidazole zinc phthlocynine compound (3) has been characterized by MALDI-TOF MS, FT-IR, UV-vis, and 1H NMR spectroscopy. This new compound 3 displayed excellent selectivity towards Bi3 + ion in the presence of other competitive ions including Ca2 +, Cd2 +, Co2 + Cu2 +, Fe3 +, Hg2 +, Sn2 +, Mg2 +, Na+, Ni2 + and Pb2 + respectively. Upon addition of Bi3 + into the solution of compound 3 in DMSO, dramatic change was observed in the Q- and the B-bands in UV-visible spectra as a result of donor acceptor interactions. Reactive oxygen species (ROS) were also studied using 2,7-dichlorofluorescin diacetate (DCFH-DA) a fluorescent probe which is converted to highly fluorescent dichlorofluorescein (DCF) in the presence of ROS. This property of non-aggregating zinc phthalocyanine is promising as a photosensitizer in photodynamic therapy of cancer.

Virtual Screening Approach of Bacterial Peptide Deformylase Inhibitors Results in New Antibiotics.

PubMed

Merzoug, Amina; Chikhi, Abdelouahab; Bensegueni, Abderrahmane; Boucherit, Hanane; Okay, Sezer

2018-03-01

The increasing resistance of bacteria to antibacterial therapy poses an enormous health problem, it renders the development of new antibacterial agents with novel mechanism of action an urgent need. Peptide deformylase, a metalloenzyme which catalytically removes N-formyl group from N-terminal methionine of newly synthesized polypeptides, is an important target in antibacterial drug discovery. In this study, we report the structure-based virtual screening of ZINC database in order to discover potential hits as bacterial peptide deformylase enzyme inhibitors with more affinity as compared to GSK1322322, previously known inhibitor. After virtual screening, fifteen compounds of the top hits predicted were purchased and evaluated in vitro for their antibacterial activities against one Gram positive (Staphylococcus aureus) and three Gram negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella. pneumoniae) bacteria in different concentrations by disc diffusion method. Out of these, three compounds, ZINC00039650, ZINC03872971 and ZINC00126407, exhibited significant zone of inhibition. The results obtained were confirmed using the dilution method. Thus, these proposed compounds may aid the development of more efficient antibacterial agents. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

2,6-diacetylpyridine bis(thiosemicarbazones) zinc complexes: synthesis, structure, and biological activity.

PubMed

Rodriguez-Argüelles, M C; Belicchi Ferrari, M; Gasparri Fava, G; Pelizzi, C; Tarasconi, P; Albertini, R; Dall'Aglio, P P; Lunghi, P; Pinelli, S

1995-05-15

The reaction of zinc chloride, acetate, or perchlorate with two bis(thiosemicarbazones) of 2,6-diacetylpyridine [H2daptsc = 2,6-diacetylpyridine bis(thiosemicarbazone) and H2dapipt = 2,6-diacetylpyridine bis(hydrazinopyruvoylthiosemicarbazone)] leads to the formation of four novel complexes that have been characterized by spectroscopic studies (NMR, IR) and biological properties. The crystal structures of the two compounds--[Zn(daptsc)]2.2DMF (1) and [Zn(H2dapipt)(OH2)2](CIO4)2.3H2O (2)--also have been determined by x-ray methods from diffractometer data. Compound (1) is dimeric and the two zinc atoms have a distorted octahedral coordination. The ligand is deprotonated. In compound (2), the coordination geometry about zinc is pentagonal--bipyramidal and the ligand is in the neutral form. The molecular structure of (2) consists of cations [Zn(H2dapipt)(OH2)]2+, CIO4- disordered anions, and three water molecules of solvation. Biological studies have shown that the ligands and the complexes Zn(daptsc).1/2EtOH and Zn(H2daptsc)Cl2 have an effect in vitro on cell proliferation and differentiation (inhibition); both are concentration dependent. [Zn(daptsc)]2.2DMF (1) shows the effects at lower concentration values with respect to other compounds.

Water quality in Reedy Fork and Buffalo Creek basins in the Greensboro area, North Carolina, 1986-87

USGS Publications Warehouse

Davenport, M.S.

1989-01-01

Water and bottom-sediment samples were collected from April 1986 through September 1987 at 19 sites in Guilford County and the City of Greensboro, North Carolina. Sampling locations included 13 stream sites, two lakes that supply the City of Greensboro with drinking water, two City of Greensboro finished drinking-water filtration plants, and effluent from the two municipal wastewater plants prior to outfall into receiving streams. Water sampling consisted of six surveys during various stages of steady ground-water flow at all sites and high-flow-event sampling during two storms at six sites. Bottom-sediment samples were collected at three sites during two routine sampling surveys. A summary of nearly 22, 000 separate chemical or physical analyses of water samples or bottom sediment is presented and discussed as individual values, ranges of values, or median values with respect to the locations of sampling sites, streamflow conditions, or other information bearing on water-quality conditions under discussion. The results include discussions of general water-quality indicators; major ion, nutrient, and trace-element concentrations; acid and base/neutral extractable organic compounds; volatile organic compounds; and organochlorine and organophosphorus pesticides detected at each sampling site. Loadings of selected constituents are also estimated on a yearly and daily basis. The quality of the raw and finished water, municipal effluents, and streams in the Greensboro area are characterized by using State and Federal water-quality standards. Inorganic constituents most commonly found in excess of standards were iron, copper, zinc, arsenic, phosphorus, manganese, cyanide, and mercury. Relatively few organic compounds were detected; however, those consistently reported were phthalate, thihalomethane, organophosphorus pesticide, benzol, and phenolic compounds. Selected inorganic, physical, and total organic carbon data are used in a Wilcoxon test for two independent variables to statistically compare water-quality characteristics in selected rural, semideveloped and urban basins. During low-flow sampling, the constituents that differed significantly among all sites were calcium, magnesium, and chloride. During low flows, concentrations of orthophosphate, fluoride, sulfate, and TOC differed at the urban site from the rural and semideveloped and urban sites. There were no significant differences among sites in concentrations of sodium, suspended sediment, nickel, zinc, copper, and mercury during low flows. The Wilcoxon test performed on high-flow data indicated that concentrations of TOC, chloride, sulfate, suspended sediment, and nickel were not significantly different among the sites.

Synthesis and Crystal Structure of Dibromido{2-[(4-tert-butylmethylphenyl) iminomethyl]pyridine-κ2 N, N'}Zinc

NASA Astrophysics Data System (ADS)

Khalaj, M.; Ghazanfarpour-Darjani, M.; Seftejani, F. B.; Lalegani, A.

2017-12-01

The title compound [Zn( dip)Br2] was synthesized using the Schiff base bidentate ligand (E)-4- tert-butyl- N-(pyridine-2-ylmethylene)benzeneamine ( dip) and zinc(II) bromide salts. It has been characterized by elemental analysis, X-ray diffraction, and optical spectroscopy. The X-ray diffraction analysis demonstrates that in this structure, the zinc(II) ion is located on an inversion center and exhibits a ZnN2Br2 tetrahedral geometry. In this structure the dip ligand is coordinated with zinc(II) ion in a cyclic-bidentate fashion forming a five-membered metallocyclic ring. The compound crystallizes in the monoclinic sp. gr. P21/ m with a = 9.2700(13) Å, b = 7.6128(11) Å, c = 12.3880(17) Å, and β = 97.021(3)°.

Two Polymorphs of an Organic-Zincophosphate Incorporating a Terephthalate Bridging Ligand in an Unusual Bonding Mode.

PubMed

Wang, Chih-Min; Pan, Ming-Feng; Chen, Yen-Chieh; Lin, Hsiu-Mei; Chung, Mei-Ying; Wen, Yuh-Sheng; Lii, Kwang-Hwa

2017-07-17

Two new polymorphs of a zinc phosphate incorporating the terephthalate organic ligand 1,4-benzenedicarboxylate (BDC), (H 2 DA)Zn 2 (cis-BDC)(HPO 4 ) 2 (1) and (H 2 DA)Zn 2 (trans-BDC)(HPO 4 ) 2 (2), where DA = 1,7-diaminoheptane, were synthesized via a hydro(solvo)thermal method at different reaction temperatures and structurally characterized by single-crystal X-ray diffraction. Interestingly, the BDC ligands, which adopt the bis-monodentate coordination model with a unusual cis type for compound 1 and with a trans linkage for compound 2, bridge the Zn atoms of the inorganic layers in the generation of two polymorphs with structural diversities (one kind of arrangement of the layered zincophosphate layer in 1; the flat and zigzag sheets of inorganic networks in 2). A simple method for tuning the optical luminescence of the title compound from blue, red, green, yellow, and pink to white emission by stirring powdered samples in lanthanide-cation-containing aqueous ethanol solutions at room temperature for 1-2 h is also presented.

Nanoscale lamellar photoconductor hybrids and methods of making same

DOEpatents

Stupp, Samuel I; Goldberger, Josh; Sofos, Marina

2013-02-05

An article of manufacture and methods of making same. In one embodiment, the article of manufacture has a plurality of zinc oxide layers substantially in parallel, wherein each zinc oxide layer has a thickness d.sub.1, and a plurality of organic molecule layers substantially in parallel, wherein each organic molecule layer has a thickness d.sub.2 and a plurality of molecules with a functional group that is bindable to zinc ions, wherein for every pair of neighboring zinc oxide layers, one of the plurality of organic molecule layers is positioned in between the pair of neighboring zinc oxide layers to allow the functional groups of the plurality of organic molecules to bind to zinc ions in the neighboring zinc oxide layers to form a lamellar hybrid structure with a geometric periodicity d.sub.1+d.sub.2, and wherein d.sub.1 and d.sub.2 satisfy the relationship of d.sub.1.ltoreq.d.sub.2.ltoreq.3d.sub.1.

Blue fluorescence of three metal-organic zinc polymers containing tetrazinc units and asymmetric ligand of btc{sup 3-}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu Ling; Graduate School of Chinese Academy of Sciences, Beijing 100039; Liu Bing

2005-11-15

Three new zinc coordination polymers [Zn{sub 2}(btc){sub 2}(H{sub 2}O){sub 2}] {sub n} .n[Zn(H{sub 2}O){sub 6}] (1), [Zn{sub 3}(btc){sub 2}(2,2'-bipy){sub 2}(H{sub 2}O){sub 3}] {sub n} .2nH{sub 2}O (2) and [Zn{sub 3}(btc){sub 2}(H{sub 2}O){sub 6}] {sub n} .nH{sub 2}O (3) (H{sub 3}btc=1,2,4-benzenetricarboxylic acid, 2,2'-bipy=2,2'-bipyridine) were obtained by the diffusion method and their crystal structures were determined by single-crystal X-ray diffraction. Compounds 1-3 have the similar tetrametallic unit [Zn{sub 4}(btc){sub 2}] SBUs and these SBUs are further connected into stair-like structure, 2-D layer and 3-D framework for 1, 2 and 3, in which the btc{sup 3-} ligands adopt {mu} {sub 3}, {mu} {submore » 4} and {mu} {sub 5} coordination modes, respectively. The title compounds show strong blue fluorescence, which may be assigned as {pi}*{sup {yields}}n transition of the ligand mixed with the ligand-to-metal change transfer (LMCT), indicating the fluorescence, indicates the title compounds may be good candidates for blue-light photoactive materials.« less

Ligand-based virtual screening and inductive learning for identification of SIRT1 inhibitors in natural products.

PubMed

Sun, Yunan; Zhou, Hui; Zhu, Hongmei; Leung, Siu-wai

2016-01-25

Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase, and its dysregulation can lead to ageing, diabetes, and cancer. From 346 experimentally confirmed SIRT1 inhibitors, an inhibitor structure pattern was generated by inductive logic programming (ILP) with DMax Chemistry Assistant software. The pattern contained amide, amine, and hetero-aromatic five-membered rings, each of which had a hetero-atom and an unsubstituted atom at a distance of 2. According to this pattern, a ligand-based virtual screening of 1 444 880 active compounds from Chinese herbs identified 12 compounds as inhibitors of SIRT1. Three compounds (ZINC08790006, ZINC08792229, and ZINC08792355) had high affinity (-7.3, -7.8, and -8.6 kcal/mol, respectively) for SIRT1 as estimated by molecular docking software AutoDock Vina. This study demonstrated a use of ILP and background knowledge in machine learning to facilitate virtual screening.

DESCRIPTIVE ANALYSIS OF DIVALENT SALTS

PubMed Central

YANG, HEIDI HAI-LING; LAWLESS, HARRY T.

2005-01-01

Many divalent salts (e.g., calcium, iron, zinc), have important nutritional value and are used to fortify food or as dietary supplements. Sensory characterization of some divalent salts in aqueous solutions by untrained judges has been reported in the psychophysical literature, but formal sensory evaluation by trained panels is lacking. To provide this information, a trained descriptive panel evaluated the sensory characteristics of 10 divalent salts including ferrous sulfate, chloride and gluconate; calcium chloride, lactate and glycerophosphate; zinc sulfate and chloride; and magnesium sulfate and chloride. Among the compounds tested, iron compounds were highest in metallic taste; zinc compounds had higher astringency and a glutamate-like sensation; and bitterness was pronounced for magnesium and calcium salts. Bitterness was affected by the anion in ferrous and calcium salts. Results from the trained panelists were largely consistent with the psychophysical literature using untrained judges, but provided a more comprehensive set of oral sensory attributes. PMID:16614749

Ligand-based virtual screening and inductive learning for identification of SIRT1 inhibitors in natural products

NASA Astrophysics Data System (ADS)

Sun, Yunan; Zhou, Hui; Zhu, Hongmei; Leung, Siu-Wai

2016-01-01

Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase, and its dysregulation can lead to ageing, diabetes, and cancer. From 346 experimentally confirmed SIRT1 inhibitors, an inhibitor structure pattern was generated by inductive logic programming (ILP) with DMax Chemistry Assistant software. The pattern contained amide, amine, and hetero-aromatic five-membered rings, each of which had a hetero-atom and an unsubstituted atom at a distance of 2. According to this pattern, a ligand-based virtual screening of 1 444 880 active compounds from Chinese herbs identified 12 compounds as inhibitors of SIRT1. Three compounds (ZINC08790006, ZINC08792229, and ZINC08792355) had high affinity (-7.3, -7.8, and -8.6 kcal/mol, respectively) for SIRT1 as estimated by molecular docking software AutoDock Vina. This study demonstrated a use of ILP and background knowledge in machine learning to facilitate virtual screening.

Zinc oxide crystal whiskers as a novel sorbent for solid-phase extraction of flavonoids.

PubMed

Wang, Licheng; Shangguan, Yangnan; Hou, Xiudan; Jia, Yong; Liu, Shujuan; Sun, Yingxin; Guo, Yong

2017-08-15

As a novel solid-phase extraction material, zinc oxide crystal whiskers were used to extract flavonoid compounds and showed good extraction abilities. X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy and surface area/pore volume characterized the sorbent. The zinc oxide was packed into a solid-phase extraction micro-column and its extraction ability was evaluated by four model flavonoid compounds. The sample loading and elution parameters were optimized and the zinc oxide based analytical method for flavonoids was established. It showed that the method has wide linearities from 1 to 150μg/L and low limits of detection at 0.25μg/L. The relative standard deviations of a single column repeatability and column to column reproducibility were less than 6.8% and 10.6%. Several real samples were analyzed by the established method and satisfactory results were obtained. The interactions between flavonoids and zinc oxide were calculated and proved to be from the Van der Waals' forces between the 4p and 5d orbitals from zinc atom and the neighboring π orbitals from flavonoid phenyl groups. Moreover, the zinc oxide crystal whiskers showed good stability and could be reused more than 50 times under the operation conditions. This work proves that the zinc oxide crystal whiskers are a good candidate for flavonoids enrichment. Copyright © 2017. Published by Elsevier B.V.

Synthesis, structure and reactivity of [Tm(Bu(t))]ZnH, a monomeric terminal zinc hydride compound in a sulfur-rich coordination environment: access to a heterobimetallic compound.

PubMed

Kreider-Mueller, Ava; Quinlivan, Patrick J; Rauch, Michael; Owen, Jonathan S; Parkin, Gerard

2016-02-07

The first terminal zinc hydride complex that features a sulfur-rich coordination environment, namely the tris(2-mercapto-1-tert-butylimidazolyl)hydroborato compound, [Tm(Bu(t))]ZnH, has been synthesized via the reaction of [Tm(Bu(t))]ZnOPh with PhSiH3. The Zn-H bond of [Tm(Bu(t))]ZnH is subject to insertion of CO2 and facile protolytic cleavage, of which the latter provides access to heterobimetallic [Tm(Bu(t))]ZnMo(CO)3Cp.

Virtual Screening of compounds to 1-deoxy-Dxylulose 5-phosphate reductoisomerase (DXR) from Plasmodium falciparum.

PubMed

Chaudhary, Kamal Kumar; Prasad, C V S Siva

2014-01-01

The 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) protein (Gen Bank ID AAN37254.1) from Plasmodium falciparum is a potential drug target. Therefore, it is of interest to screen DXR against a virtual library of compounds (at the ZINC database) for potential binders as possible inhibitors. This exercise helped to choose 10 top ranking molecules with ZINC00200163 [N-(2,2di methoxy ethyl)-6-methyl-2, 3, 4, 9-tetrahydro-1H-carbazol-1-amine] a having good fit (-6.43 KJ/mol binding energy) with the target protein. Thus, ZINC00200163 is identified as a potential molecule for further comprehensive characterization and in-depth analysis.

Byproduct-free mass production of compound semiconductor nanowires: zinc phosphide

NASA Astrophysics Data System (ADS)

Chen, Yixi; Polinnaya, Rakesh; Vaddiraju, Sreeram

2018-05-01

A method for the mass production of compound semiconductor nanowires that involves the direct reaction of component elements in a chemical vapor deposition chamber (CVD) is presented. This method results in nanowires, without the associated production of any other byproducts such as nanoparticles or three-dimensional (3D) bulk crystals. Furthermore, no unreacted reactants remain mixed with the nanowire product in this method. This byproduct-free nanowire production thus circumvents the need to tediously purify and collect nanowires from a mixture of products/reactants after their synthesis. Demonstration made using zinc phosphide (Zn3P2) material system as an example indicated that the direct reaction of zinc microparticles with phosphorus supplied via the vapor phase results in the production of gram quantities of nanowires. To enhance thermal transport and achieve the complete reaction of zinc microparticles, while simultaneously ensuring that the microparticles do not agglomerate into macroscale zinc particles and partly remain unreacted (owing to diffusion limitations), pellets composed of mixtures of zinc and a sacrificial salt, NH4Cl, were employed as the starting material. The sublimation by decomposition of NH4Cl in the early stages of the reaction leaves a highly porous pellet of zinc composed of only zinc microparticles, which allows for inward diffusion of phosphorus/outward diffusion of zinc and the complete conversion of zinc into Zn3P2 nanowires. NH4Cl also aids in removal of any native oxide layer present on the zinc microparticles that may prevent their reaction with phosphorus. This method may be used to mass produce many other nanowires in a byproduct-free manner, besides Zn3P2.

Corrosion-Resistant Alkyd Coatings

DTIC Science & Technology

1992-02-18

molecule. Examples of such acid compounds include the aliphatic saturated dibasic acids such as succinic acid , adipic acid , azelaic acid , sebacic...of a benzoic acid . 15. SUBJECT TERMS corrosion control, single topcoat, one coat 16. SECURITY CLASSIFICATION OF: unclassified a. REPORT...consisting essentially of critical amounts of at least one zinc phos- phate, zinc molybdate and at least one zinc salt of a benzoic acid . 15

[FEATURES OF THE CONTENT OF MOVABLE FORMS OF HEAVY METALS AND SELENIUM IN SOILS OF THE YAROSLAVL REGION].

PubMed

Bakaeva, E A; Eremeyshvili, A V

2016-01-01

With the use of the method of inversion voltammetry there was analyzed the content of movableforms of trace elements: (selenium, zinc, copper lead, cadmium) in soils in the Yaroslavl district of the Yaroslavl region, and also content of zinc, copper lead, cadmium in soils and snow cover in the city of Yaroslavl. According to values of concentrations of movable compounds in soils determined trace elements can be ranked into the following row: zinc > lead > copper > selenium > cadmium. There was revealed insufficient if compared with literature data concentrations, content of movable compounds of selenium, copper and zinc in examined explored soils. The maximal concentrations of lead are revealed in the close proximity to both the city of Yaroslavl and large highways of the city. It indicates to the anthropogenic pollution of soils by this element.

Anaerobic Digestion Alters Copper and Zinc Speciation.

PubMed

Legros, Samuel; Levard, Clément; Marcato-Romain, Claire-Emmanuelle; Guiresse, Maritxu; Doelsch, Emmanuel

2017-09-19

Anaerobic digestion is a widely used organic waste treatment process. However, little is known on how it could alter the speciation of contaminants in organic waste. This study was focused on determining the influence of anaerobic digestion on the speciation of copper and zinc, two metals that generally occur at high concentration in organic waste. Copper and zinc speciation was investigated by X-ray absorption spectroscopy in four different raw organic wastes (predigestion) and their digested counterparts (postdigestion, i.e., digestates). The results highlighted an increase in the digestates of the proportion of amorphous or nanostructured copper sulfides as well as amorphous or nanostructured zinc sulfides and zinc phosphate as compared to raw waste. We therefore suggest that the environmental fate of these elements would be different when spreading either digestates or raw waste on cropland.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-interactive Chemicals Contained in Boundary Layer-targeted Emulsions

NASA Technical Reports Server (NTRS)

Richmond, Robert Chafee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor)

2013-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor)

2017-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, water, or a water-based lubricant. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Harry F., Jr. (Inventor)

2016-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Two Zn coordination polymers with meso-helical chains based on mononuclear or dinuclear cluster units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Ling, E-mail: qinling@hfut.edu.cn; Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials; State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093

2016-07-15

Two zinc coordination polymers {[Zn_2(TPPBDA)(oba)_2]·DMF·1.5H_2O}{sub n} (1), {[Zn(TPPBDA)_1_/_2(tpdc)]·DMF}{sub n} (2) have been synthesized by zinc metal salt, nanosized tetradentate pyridine ligand with flexible or rigid V-shaped carboxylate co-ligands. These complexes were characterized by elemental analyses and X-ray single-crystal diffraction analyses. Compound 1 is a 2-fold interpenetrated 3D framework with [Zn{sub 2}(CO{sub 2}){sub 4}] clusters. Compound 2 can be defined as a five folded interpenetrating bbf topology with mononuclear Zn{sup 2+}. These mononuclear or dinuclear cluster units are linked by mix-ligands, resulting in various degrees of interpenetration. In addition, the photoluminescent properties for TPPBDA ligand under different state and coordination polymersmore » have been investigated in detail. - Graphical abstract: Two zinc coordination polymers have been synthesized by zinc metal salt, nanosized tetradentate pyridine ligand with flexible or rigid V-shaped carboxylate co-ligands. Compound 1 is a 2-fold interpenetrated 3D framework with [Zn{sub 2}(CO{sub 2}){sub 4}] clusters. Compound 2 can be defined as a five folded interpenetrating bbf topology with mononuclear Zn{sup 2+}. In addition, the photoluminescent properties for TPPBDA ligand under different status and coordination polymers have been investigated in detail. Display Omitted - Highlights: • Two Zn coordination polymers based on mononuclear or dinuclear cluster units have been synthesized. • Compound 1 is a 2-fold interpenetrated 3D framework with [Zn{sub 2}(CO{sub 2}){sub 4}] clusters. • Compound 2 is a five folded interpenetrating bbf topology with mononuclear Zn{sup 2+}. • The photoluminescent properties for TPPBDA with different state and two coordination polymers have been investigated.« less

Risks of Using Antifouling Biocides in Aquaculture

PubMed Central

Guardiola, Francisco Antonio; Cuesta, Alberto; Meseguer, José; Esteban, Maria Angeles

2012-01-01

Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211®), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms. PMID:22408407

Risks of using antifouling biocides in aquaculture.

PubMed

Guardiola, Francisco Antonio; Cuesta, Alberto; Meseguer, José; Esteban, Maria Angeles

2012-01-01

Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211(®)), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms.

Characterization and Influence of Green Synthesis of Nano-Sized Zinc Complex with 5-Aminolevulinic Acid on Bioactive Compounds of Aniseed.

PubMed

Tavallali, Vahid; Rahmati, Sadegh; Rowshan, Vahid

2017-11-01

A new water soluble zinc-aminolevulinic acid nano complex (n[Zn(ALA) 2 ]), which was characterized by TEM, IR, and EDX spectra, has been prepared via sonochemical method under green conditions in water. In the current study, the effectiveness of foliar Zn amendment using synthetic Zn-ALA nano complex, as a new introduced Zn-fertilizer here, was evaluated. As the model plant, Pimpinella anisum, the most valuable spice and medicinal plant grown in warm regions, was used. By using zinc nano complex, further twenty compounds were obtained in the essential oil of anise plants. Application of 0.2% (w/v) Zn-ALA nano complex increased the levels of (E)-anethole, β-bisabolene, germacrene D, methyl chavicol, and α-zingiberene in the essential oil. Nano Zn complex at the rate of 0.2% induced considerable high phenolic compounds and zinc content of shoots and seeds. Chlorogenic acid had the highest level between four detected phenolic compounds. The maximum antioxidant activity was monitored through the application of Zn nano complex. According to the results, nanoscale nutrients can be provided with further decreased doses for medicinal plants. Using Zn-ALA nano complex is a new and efficient method to improve the pharmaceutical and food properties of anise plants. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Efficacy of zinc compounds in controlling Fusarium head blight and deoxynivalenol formation in wheat (Triticum aestivum L.).

PubMed

Savi, Geovana D; Piacentini, Karim C; de Souza, Stephany Ramos; Costa, Maíra E B; Santos, Cristina M R; Scussel, Vildes M

2015-07-16

The efficiency of zinc compounds (zinc sulfate, ZnSO4 and zinc oxide, ZnO in regular and nanosize, respectively) on wheat plants was evaluated against growth of Fusarium graminearum and DON formation. In addition, any possible effects on the grain microstructures were observed by scanning electron microscopy (SEM), and the remaining residue of Zn on wheat plants was analyzed. The plants were inoculated with F. graminearum and treated with Zn compounds (100mM) onto spikelets at the anthesis stage. When wheat plants reached maturation, grains were harvested and evaluated for Fusarium (number of colonies, CFU/g), DON formation, and SEM observation, followed by determination of possible remaining Zn residue. The groups treated with ZnSO4 and ZnO-NP showed a reduction in number of CFU of F. graminearum when compared to the control. Similarly for DON formation, i.e. the toxin was reduced to non-detected levels in the treated group. ZnO-NP efficiently reduced F. graminearum and DON formation in the grains at low concentration. Zn remained within the international recommended level for consumption and the treatment did not cause any damage to wheat grains. New strategies of control using Zn compounds in addition to conventional treatments could increase the efficiency against FBH and DON formation. Copyright © 2015 Elsevier B.V. All rights reserved.

Interaction of zinc with dental mineral.

PubMed

Ingram, G S; Horay, C P; Stead, W J

1992-01-01

As some currently available toothpastes contain zinc compounds, the reaction of zinc with dental mineral and its effect on crystal growth rates were studied using three synthetic calcium-deficient hydroxyapatites (HAP) as being representative of dental mineral. Zinc was readily acquired by all HAP samples in the absence of added calcium, the amount adsorbed being proportional to the HAP surface area; about 9 mumol Zn/m2 was adsorbed at high zinc concentrations. As zinc was acquired, calcium was released, consistent with 1:1 Ca:Zn exchange. Soluble calcium reduced zinc uptake and similarly, calcium post-treatment released zinc. Pretreatment of HAP with 0.5 mM zinc reduced its subsequent ability to undergo seeded crystal growth, as did extracts of a toothpaste containing 0.5% zinc citrate, even in the presence of saliva. The reverse reaction, i.e. displacement of adsorbed zinc by salivary levels of calcium, however, indicates the mechanism by which zinc can reduce calculus formation in vivo by inhibiting plaque mineralisation without adversely affecting the anti-caries effects of fluoride.

Effects of land use on ground-water quality in central Florida; preliminary results, US Geological Survey Toxic Waste-Ground Water Contamination Program

USGS Publications Warehouse

Rutledge, A.T.

1987-01-01

Groundwater is the principal source of drinking water in central Florida. The most important hydrogeologic unit is the Floridan aquifer system, consisting of fractured limestone and dolomite limestone. Activities of man in areas of recharge to the Floridian aquifer system that may be affecting groundwater quality include: (1) the use of drainage wells for stormwater disposal in urban areas, (2) the use of pesticides and fertilizers in citrus groves, and (3) the mining and processing of phosphate ore in mining areas. Preliminary findings about the impacts of these land uses on ground-water quality by comparison with a fourth land use representing the absence of human activity in another area of recharge are presented. Drainage wells convey excess urban stormwater directly to the Upper Floridian aquifer. The volatile organic compounds are the most common contaminants in ground water. Trace elements such as chromium and lead are entering the aquifer but their movement is apparently attenuated by precipitation reactions associated with high pH or by cation-exchange reactions. Among the trace elements and organic chemicals, most ground-water contamination in citrus production areas is caused by pesticides, which include the organic compounds simazine, ametryne, chlordane, DDE , bromacil, aldicarb, EDB, trifluralin, and diazinon, and the trace elements zinc and copper; other contaminants include benzene, toluene, napthalene, and indene compounds. In the phosphate mining area, constituents of concern are arsenic, selenium, and mercury, and secondarily lead, chromium, cadmium, and others. Organic compounds such as fluorene, naphthalene, di-n-butyl phthalate, alkylated benzenes and naphthalenes, and indene compounds also are entering groundwater. (Author 's abstract)

Functional studies of Drosophila zinc transporters reveal the mechanism for dietary zinc absorption and regulation

PubMed Central

2013-01-01

Background Zinc is key to the function of many proteins, but the process of dietary zinc absorption is not well clarified. Current knowledge about dietary zinc absorption is fragmented, and mostly derives from incomplete mammalian studies. To gain a comprehensive picture of this process, we systematically characterized all zinc transporters (that is, the Zip and ZnT family members) for their possible roles in dietary zinc absorption in a genetically amenable model organism, Drosophila melanogaster. Results A set of plasma membrane-resident zinc transporters was identified to be responsible for absorbing zinc from the lumen into the enterocyte and the subsequent exit of zinc to the circulation. dZip1 and dZip2, two functionally overlapping zinc importers, are responsible for absorbing zinc from the lumen into the enterocyte. Exit of zinc to the circulation is mediated through another two functionally overlapping zinc exporters, dZnT1, and its homolog CG5130 (dZnT77C). Somewhat surprisingly, it appears that the array of intracellular ZnT proteins, including the Golgi-resident dZnT7, is not directly involved in dietary zinc absorption. By modulating zinc status in different parts of the body, we found that regulation of dietary zinc absorption, in contrast to that of iron, is unresponsive to bodily needs or zinc status outside the gut. The zinc transporters that are involved in dietary zinc absorption, including the importers dZip1 and dZip2, and the exporter dZnT1, are respectively regulated at the RNA and protein levels by zinc in the enterocyte. Conclusions Our study using the model organism Drosophila thus starts to reveal a comprehensive sketch of dietary zinc absorption and its regulatory control, a process that is still incompletely understood in mammalian organisms. The knowledge gained will act as a reference for future mammalian studies, and also enable an appreciation of this important process from an evolutionary perspective. PMID:24063361

Relative contribution of phytates, fibers, and tannins to low iron and zinc in vitro solubility in pearl millet (Pennisetum glaucum) flour and grain fractions.

PubMed

Lestienne, Isabelle; Caporiccio, Bertrand; Besançon, Pierre; Rochette, Isabelle; Trèche, Serge

2005-10-19

In vitro digestions were performed on pearl millet flours with decreased phytate contents and on two dephytinized or nondephytinized pearl millet grain fractions, a decorticated fraction, and a bran fraction with low and high fiber and tannin contents, respectively. Insoluble residues of these digestions were then incubated with buffer or enzymatic solutions (xylanases and/or phytases), and the quantities of indigestible iron and zinc released by these different treatments were determined. In decorticated pearl millet grain, iron was chelated by phytates and by insoluble fibers, whereas zinc was almost exclusively chelated by phytates. In the bran of pearl millet grain, a high proportion of iron was chelated by iron-binding phenolic compounds, while the rest of iron as well as the majority of zinc were chelated in complexes between phytates and fibers. The low effect of phytase action on iron and zinc solubility of bran of pearl millet grain shows that, in the case of high fiber and tannin contents, the chelating effect of these compounds was higher than that of phytates.

Preparation of Zinc Oxide (ZnO) Thin Film as Transparent Conductive Oxide (TCO) from Zinc Complex Compound on Thin Film Solar Cells: A Study of O2 Effect on Annealing Process

NASA Astrophysics Data System (ADS)

Muslih, E. Y.; Kim, K. H.

2017-07-01

Zinc oxide (ZnO) thin film as a transparent conductive oxide (TCO) for thin film solar cell application was successfully prepared through two step preparations which consisted of deposition by spin coating at 2000 rpm for 10 second and followed by annealing at 500 °C for 2 hours under O2 and ambient atmosphere. Zinc acetate dehydrate was used as a precursor which dissolved in ethanol and acetone (1:1 mol) mixture in order to make a zinc complex compound. In this work, we reported the O2 effect, reaction mechanism, structure, morphology, optical and electrical properties. ZnO thin film in this work shows a single phase of wurtzite, with n-type semiconductor and has band gap, carrier concentration, mobility, and resistivity as 3.18 eV, 1.21 × 10-19cm3, 11 cm2/Vs, 2.35 × 10-3 Ωcm respectively which is suitable for TCO at thin film solar cell.

Assessing the anti-fungal efficiency of filters coated with zinc oxide nanoparticles

NASA Astrophysics Data System (ADS)

Decelis, Stephen; Sardella, Davide; Triganza, Thomas; Brincat, Jean-Pierre; Gatt, Ruben; Valdramidis, Vasilis P.

2017-05-01

Air filters support fungal growth, leading to generation of conidia and volatile organic compounds, causing allergies, infections and food spoilage. Filters that inhibit fungi are therefore necessary. Zinc oxide (ZnO) nanoparticles have anti-fungal properties and therefore are good candidates for inhibiting growth. Two concentrations (0.012 M and 0.12 M) were used to coat two types of filters (melt-blown and needle-punched) for three different periods (0.5, 5 and 50 min). Rhizopus stolonifer and Penicillium expansum isolated from spoiled pears were used as test organisms. Conidial suspensions of 105 to 103 spores ml-1 were prepared in Sabouraud dextrose agar at 50°C, and a modified slide-culture technique was used to test the anti-fungal properties of the filters. Penicillium expansum was the more sensitive organism, with inhibition at 0.012 M at only 0.5 min coating time on the needle-punched filter. The longer the coating time, the more effective inhibition was for both organisms. Furthermore, it was also determined that the coating process had only a slight effect on the Young's Moduli of the needle-punched filters, while the Young's Moduli of the melt-blown filters is more susceptible to the coating method. This work contributes to the assessment of the efficacy of filter coating with ZnO nanopaticles aimed at inhibiting fungal growth.

Assessing the anti-fungal efficiency of filters coated with zinc oxide nanoparticles

PubMed Central

Decelis, Stephen; Sardella, Davide; Triganza, Thomas; Brincat, Jean-Pierre; Gatt, Ruben

2017-01-01

Air filters support fungal growth, leading to generation of conidia and volatile organic compounds, causing allergies, infections and food spoilage. Filters that inhibit fungi are therefore necessary. Zinc oxide (ZnO) nanoparticles have anti-fungal properties and therefore are good candidates for inhibiting growth. Two concentrations (0.012 M and 0.12 M) were used to coat two types of filters (melt-blown and needle-punched) for three different periods (0.5, 5 and 50 min). Rhizopus stolonifer and Penicillium expansum isolated from spoiled pears were used as test organisms. Conidial suspensions of 105 to 103 spores ml−1 were prepared in Sabouraud dextrose agar at 50°C, and a modified slide-culture technique was used to test the anti-fungal properties of the filters. Penicillium expansum was the more sensitive organism, with inhibition at 0.012 M at only 0.5 min coating time on the needle-punched filter. The longer the coating time, the more effective inhibition was for both organisms. Furthermore, it was also determined that the coating process had only a slight effect on the Young's Moduli of the needle-punched filters, while the Young's Moduli of the melt-blown filters is more susceptible to the coating method. This work contributes to the assessment of the efficacy of filter coating with ZnO nanopaticles aimed at inhibiting fungal growth. PMID:28572995

Assessing the anti-fungal efficiency of filters coated with zinc oxide nanoparticles.

PubMed

Decelis, Stephen; Sardella, Davide; Triganza, Thomas; Brincat, Jean-Pierre; Gatt, Ruben; Valdramidis, Vasilis P

2017-05-01

Air filters support fungal growth, leading to generation of conidia and volatile organic compounds, causing allergies, infections and food spoilage. Filters that inhibit fungi are therefore necessary. Zinc oxide (ZnO) nanoparticles have anti-fungal properties and therefore are good candidates for inhibiting growth. Two concentrations (0.012 M and 0.12 M) were used to coat two types of filters (melt-blown and needle-punched) for three different periods (0.5, 5 and 50 min). Rhizopus stolonifer and Penicillium expansum isolated from spoiled pears were used as test organisms. Conidial suspensions of 10 5 to 10 3 spores ml -1 were prepared in Sabouraud dextrose agar at 50°C, and a modified slide-culture technique was used to test the anti-fungal properties of the filters. Penicillium expansum was the more sensitive organism, with inhibition at 0.012 M at only 0.5 min coating time on the needle-punched filter. The longer the coating time, the more effective inhibition was for both organisms. Furthermore, it was also determined that the coating process had only a slight effect on the Young's Moduli of the needle-punched filters, while the Young's Moduli of the melt-blown filters is more susceptible to the coating method. This work contributes to the assessment of the efficacy of filter coating with ZnO nanopaticles aimed at inhibiting fungal growth.

Contamination of ground water, surface water, and soil, and evaluation of selected ground-water pumping alternatives in the Canal Creek area of Aberdeen Proving Ground, Maryland

USGS Publications Warehouse

Lorah, Michelle M.; Clark, Jeffrey S.

1996-01-01

Chemical manufacturing, munitions filling, and other military-support activities have resulted in the contamination of ground water, surface water, and soil in the Canal Creek area of Aberdeen Proving Ground, Maryland. Chlorinated volatile organic compounds, including 1,1,2,2-tetrachloroethane and trichloroethylene, are widespread ground-water contaminants in two aquifers that are composed of unconsolidated sand and gravel. Distribution and fate of chlorinated organic compounds in the ground water has been affected by the movement and dissolution of solvents in their dense immiscible phase and by microbial degradation under anaerobic conditions. Detection of volatile organic contaminants in adjacent surface water indicates that shallow contaminated ground water discharges to surface water. Semivolatile organic compounds, especially polycyclic aromatic hydrocarbons, are the most prevalent organic contaminants in soils. Various trace elements, such as arsenic, cadmium, lead, and zinc, were found in elevated concentrations in ground water, surface water, and soil. Simulations with a ground-water-flow model and particle tracker postprocessor show that, without remedial pumpage, the contaminants will eventually migrate to Canal Creek and Gunpowder River. Simulations indicate that remedial pumpage of 2.0 million gallons per day from existing wells is needed to capture all particles originating in the contaminant plumes. Simulated pumpage from offsite wells screened in a lower confined aquifer does not affect the flow of contaminated ground water in the Canal Creek area.

The significance of the source of zinc and its anti-VSC effect.

PubMed

Rölla, G; Jonski, G; Young, A

2002-06-01

The anti-VSC (volatile sulphur compounds) effect of zinc is known to be associated with free zinc ions. To examine whether zinc salts with low stability constants were more suitable as sources of zinc in zinc lozenges than zinc salts with high stability constants. The former provide free zinc ions upon dissolution in water, whereas the latter provide few such ions. Identical lozenges were produced which contained either zinc acetate, zinc gluconate (low stability constants), zinc citrate or amino-acid chelated zinc (extremely high stability constants). All the lozenges contained 0.1 per cent of zinc. A test panel of 10 volunteers used the different lozenges randomly. VSC were measured by GC. The lozenge with the highest stability constant was as effective as those with very low stability constants. The anti-VSC effect was thus not related to this constant. These findings may be explained by the possibility that alternative ligands with stronger affinity for zinc than the original ligands in the lozenges may be present in the oral cavity. An in vitro experiment indicated that the sulphide ion (S2-) may be such a ligand.

Dynamic changes in the distribution of minerals in relation to phytic acid accumulation during rice seed development.

PubMed

Iwai, Toru; Takahashi, Michiko; Oda, Koshiro; Terada, Yasuko; Yoshida, Kaoru T

2012-12-01

Phytic acid (inositol hexakisphosphate [InsP(6)]) is the storage compound of phosphorus in seeds. As phytic acid binds strongly to metallic cations, it also acts as a storage compound of metals. To understand the mechanisms underlying metal accumulation and localization in relation to phytic acid storage, we applied synchrotron-based x-ray microfluorescence imaging analysis to characterize the simultaneous subcellular distribution of some mineral elements (phosphorus, calcium, potassium, iron, zinc, and copper) in immature and mature rice (Oryza sativa) seeds. This fine-imaging method can reveal whether these elements colocalize. We also determined their accumulation patterns and the changes in phosphate and InsP(6) contents during seed development. While the InsP(6) content in the outer parts of seeds rapidly increased during seed development, the phosphate contents of both the outer and inner parts of seeds remained low. Phosphorus, calcium, potassium, and iron were most abundant in the aleurone layer, and they colocalized throughout seed development. Zinc was broadly distributed from the aleurone layer to the inner endosperm. Copper localized outside the aleurone layer and did not colocalize with phosphorus. From these results, we suggest that phosphorus translocated from source organs was immediately converted to InsP(6) and accumulated in aleurone layer cells and that calcium, potassium, and iron accumulated as phytic acid salt (phytate) in the aleurone layer, whereas zinc bound loosely to InsP(6) and accumulated not only in phytate but also in another storage form. Copper accumulated in the endosperm and may exhibit a storage form other than phytate.

Speciation And Bioavailability Of Zinc In Amended Sediments

EPA Science Inventory

The speciation and bioavailability of zinc (Zn) in smelter-contaminated sediments was investigated as a function of phosphate (apatite) and organic amendment loading rate. Zinc species identified in preamendment sediment were zinc hydroxide-like phases, sphalerite, and zinc sorbe...

40 CFR 437.46 - Pretreatment standards for existing sources (PSES)

Code of Federal Regulations, 2011 CFR

2011-07-01

....218 0.0662 Zinc 2.87 0.641 Organic Parameters Bis(2-ethylhexyl) phthalate 0.267 0.158 Carbazole 0.392... Titanium 0.0947 0.0618 Vanadium 0.218 0.0662 Zinc 2.87 0.641 Organic Parameters Bis(2-ethylhexyl) phthalate... Tin 0.249 0.146 Zinc 6.95 4.46 Organic Parameters Bis (2-ethylhexyl) phthalate 0.267 0.158 Carbazole 0...

[Development of an inactivated vaccine for the protection of cattle against Aujeszky's disease].

PubMed

Straub, O C

1990-07-01

The effects of an inactivated strain of Aujeszky's disease vaccine in cattle were investigated. It has not been possible to use vaccines licensed for use in pigs successfully in cattle even though cattle develop neutralizing antibodies to these vaccines. The addition of zinc compounds to the vaccines resulted in protection in cattle. The basis for the use of zinc is discussed. A mutant based vaccine was effective following local administration, but was not when administered parenterally. Anti-prostaglandin was not effective either, despite its successful use in sheep when administered with BHV1. The vaccine presents a prospect for immunising dogs and cats, and the addition of zinc compounds to other drugs and inducers is discussed.

PRODUCTION OF PURIFIED URANIUM

DOEpatents

Burris, L. Jr.; Knighton, J.B.; Feder, H.M.

1960-01-26

A pyrometallurgical method for processing nuclear reactor fuel elements containing uranium and fission products and for reducing uranium compound; to metallic uranium is reported. If the material proccssed is essentially metallic uranium, it is dissolved in zinc, the sulution is cooled to crystallize UZn/sub 9/ , and the UZn/sub 9/ is distilled to obtain uranium free of fission products. If the material processed is a uranium compound, the sollvent is an alloy of zinc and magnesium and the remaining steps are the same.

A Five-year Performance Study of Low VOC Coatings over Zinc Thermal Spray for the Protection of Carbon Steel at the Kennedy Space Center

NASA Technical Reports Server (NTRS)

Kolody, Mark R.; Curran, Jerome P.; Calle, Luz Marina

2014-01-01

The launch facilities at the Kennedy Space Center (KSC) are located approximately 1000 feet from the Atlantic Ocean where they are exposed to salt deposits, high humidity, high UV degradation, and acidic exhaust from solid rocket boosters. These assets are constructed from carbon steel, which requires a suitable coating to provide long-term protection to reduce corrosion and its associated costs. While currently used coating systems provide excellent corrosion control performance, they are subject to occupational, safety, and environmental regulations at the Federal and State levels that limit their use. Many contain high volatile organic compounds (VOCs), hazardous air pollutants, and other hazardous materials. Hazardous waste from coating operations include vacuum filters, zinc dust, hazardous paint related material, and solid paint. There are also worker safety issues such as exposure to solvents and isocyanates. To address these issues, top-coated thermal spray zinc coating systems were investigated as a promising environmentally friendly corrosion protection for carbon steel in an acidic launch environment. Additional benefits of the combined coating system include a long service life, cathodic protection to the substrate, no volatile contaminants, and high service temperatures. This paper reports the results of a performance based study to evaluate low VOC topcoats (for thermal spray zinc coatings) on carbon steel for use in a space launch environment.

Mechanisms of inhibition of zinc-finger transcription factors by selenium compounds ebselen and selenite.

PubMed

Larabee, Jason L; Hocker, James R; Hanas, Jay S

2009-03-01

The anti-inflammatory selenium compounds, ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) and selenite, were found to alter the DNA binding mechanisms and structures of cysteine-rich zinc-finger transcription factors. As assayed by DNase I protection, DNA binding by TFIIIA (transcription factor IIIA, prototypical Cys(2)His(2) zinc finger protein), was inhibited by micromolar amounts of ebselen. In a gel shift assay, ebselen inhibited the Cys(2)His(2) zinc finger-containing DNA binding domain (DBD) of the NF-kappaB mediated transcription factor Sp1. Ebselen also inhibited DNA binding by the p50 subunit of the pro-inflammatory Cys-containing NF-kappaB transcription factor. Electrospray ionization mass spectrometry (ESI-MS) was utilized to elucidate mechanisms of chemical interaction between ebselen and a zinc-bound Cys(2)His(2) zinc finger polypeptide modeled after the third finger of Sp1 (Sp1-3). Exposing Sp1-3 to micromolar amounts of ebselen resulted in Zn(2+) release from this peptide and the formation of a disulfide bond by oxidation of zinc finger SH groups, the likely mechanism for DNA binding inhibition. Selenite was shown by ESI-MS to also eject zinc from Sp1-3 as well as induce disulfide bond formation through SH oxidation. The selenite-dependent inhibition/oxidation mechanism differed from that of ebselen by inducing the formation of a stable selenotrisulfide bond. Selenite-induced selenotrisulfide formation was dependent upon the structure of the Cys(2)His(2) zinc finger as alteration in the finger structure enhanced this reaction as well as selenite-dependent zinc release. Ebselen and selenite-dependent inhibition/oxidation of Cys-rich zinc finger proteins, with concomitant release of zinc and finger structural changes, points to mechanisms at the atomic and protein level for selenium-induced alterations in Cys-rich proteins, and possible amelioration of certain inflammatory, neurodegenerative, and oncogenic responses.

Synthesis and photocatalytic property of Zinc Oxide (ZnO) fine particle using flame spray pyrolysis method

NASA Astrophysics Data System (ADS)

Widiyandari, Hendri; Ayu Ketut Umiati, Ngurah; Dwi Herdianti, Rizki

2018-05-01

Advance oxidation process (AOP) using photocatalysis constitute a promising technology for the treatment of wastewaters containing non-easily removable organic compound. Zinc oxide (ZnO) is one of efficient photocatalyst materials. This research reported synthesis of ZnO fine particle from zinc nitrate hexahydrate using Flame Spray Pyrolysis (FSP) method. In this method, oxygen (O2) gas were used as oxidizer and LPG (liquid petroleum gas) were used as fuel. The effect of O2 gas flow rate during ZnO particle fabrication to the microstructure, optical and photocatalytic properties were systematically discussed. The photocatalytic activity of ZnO was tested for the degradation of amaranth dye with initial concentration of 10 ppm under irradiation of solar simulator. The rate of decrease in amaranth concentration was measured using UV-Visible spectrophotometer. The ZnO synthesized using FSP has a hexagonal crystalline structure. Scanning electron microscope images showed that ZnO has a spherical formed which was the mixture of solid and hollow particles. The optimum condition for amaranth degradation was shown by ZnO produced at a flow rate of 1.5 L/min which able to degrade amaranth dye up to 95,3 % at 75 minutes irradiation.

Factors influence flexibility resistivity and zinc dendrite penetration rate of inorganic separators for alkaline batteries

NASA Technical Reports Server (NTRS)

Sheibley, D. W.

1975-01-01

Developmental work resulted in a formulation which can improve the flexibility of the inorganic-organic-type separator for silver-zinc and nickel-zinc alkaline batteries. The effects of various fillers and reactive organic additives on separator volume resistivity are described. The effects of various inert fillers on the zinc dendrite penetration rate of the separator are shown. Conclusions regarding the operating mechanism of the separator are presented.

In vitro assessment of the antimicrobial activity of silver and zinc oxide nanoparticles against fish pathogens.

PubMed

Shaalan, Mohamed Ibrahim; El-Mahdy, Magdy Mohamed; Theiner, Sarah; El-Matbouli, Mansour; Saleh, Mona

2017-07-21

Antibiotic resistance is a global issue that threatens public health. The excessive use of antibiotics contributes to this problem as the genes of antibiotic resistance can be transferred between the bacteria in humans, animals and aquatic organisms. Metallic nanoparticles could serve as future substitutes for some conventional antibiotics because of their antimicrobial activity. The aim of this study was to evaluate the antimicrobial effects of silver and zinc oxide nanoparticles against major fish pathogens and assess their safety in vitro. Silver nanoparticles were synthesized by chemical reduction and characterized with UV-Vis spectroscopy, transmission electron microscopy and zeta sizer. The concentrations of silver and zinc oxide nanoparticles were measured using inductively coupled plasma-mass spectrometry. Subsequently, silver and zinc oxide nanoparticles were tested for their antimicrobial activity against Aeromonas hydrophila, Aeromonas salmonicida subsp. salmonicida, Edwardsiella ictaluri, Edwardsiella tarda, Francisella noatunensis subsp. orientalis, Yersinia ruckeri and Aphanomyces invadans and the minimum inhibitory concentrations were determined. MTT assay was performed on eel kidney cell line (EK-1) to determine the cell viability after incubation with nanoparticles. The interaction between silver nanoparticles and A. salmonicida was investigated by transmission electron microscopy. The tested nanoparticles exhibited marked antimicrobial activity. Silver nanoparticles inhibited the growth of both A. salmonicida and A. invadans at a concentration of 17 µg/mL. Zinc oxide nanoparticles inhibited the growth of A. salmonicida, Y. ruckeri and A. invadans at concentrations of 15.75, 31.5 and 3.15 µg/mL respectively. Silver nanoparticles showed higher cell viability when compared to zinc oxide nanoparticles in the MTT assay. Transmission electron microscopy showed the attachment of silver nanoparticles to the bacterial membrane and disruption of its integrity. This is the first study on inhibitory effects of silver and zinc oxide nanoparticles towards A. salmonicida and A. invadans. Moreover, zinc oxide nanoparticles inhibited the growth of Y. ruckeri. In low concentrations, silver nanoparticles were less cytotoxic than zinc oxide nanoparticles and represent an alternative antimicrobial compound against A. hydrophila, A. salmonicida and A. invadans.

Homology modeling, molecular dynamics, and virtual screening of NorA efflux pump inhibitors of Staphylococcus aureus

PubMed Central

Bhaskar, Baki Vijaya; Babu, Tirumalasetty Muni Chandra; Reddy, Netala Vasudeva; Rajendra, Wudayagiri

2016-01-01

Emerging drug resistance in clinical isolates of Staphylococcus aureus might be implicated to the overexpression of NorA efflux pump which is capable of extruding numerous structurally diverse compounds. However, NorA efflux pump is considered as a potential drug target for the development of efflux pump inhibitors. In the present study, NorA model was constructed based on the crystal structure of glycerol-3-phosphate transporter (PDBID: 1PW4). Molecular dynamics (MD) simulation was performed using NAMD2.7 for NorA which is embedded in the hydrated lipid bilayer. Structural design of NorA unveils amino (N)- and carboxyl (C)-terminal domains which are connected by long cytoplasmic loop. N and C domains are composed of six transmembrane α-helices (TM) which exhibits pseudo-twofold symmetry and possess voluminous substrate binding cavity between TM helices. Molecular docking of reserpine, totarol, ferruginol, salvin, thioxanthene, phenothiazine, omeprazole, verapamil, nalidixic acid, ciprofloxacin, levofloxacin, and acridine to NorA found that all the molecules were bound at the large hydrophobic cleft and indicated significant interactions with the key residues. In addition, structure-based virtual screening was employed which indicates that 14 potent novel lead molecules such as CID58685302, CID58685367, CID5799283, CID5578487, CID60028372, ZINC12196383, ZINC72140751, ZINC72137843, ZINC39227983, ZINC43742707, ZINC12196375, ZINC66166948, ZINC39228014, and ZINC14616160 have highest binding affinity for NorA. These lead molecules displayed considerable pharmacological properties as evidenced by Lipinski rule of five and prophecy of toxicity risk assessment. Thus, the present study will be helpful in designing and synthesis of a novel class of NorA efflux pump inhibitors that restore the susceptibilities of drug compounds. PMID:27757014

Homology modeling, molecular dynamics, and virtual screening of NorA efflux pump inhibitors of Staphylococcus aureus.

PubMed

Bhaskar, Baki Vijaya; Babu, Tirumalasetty Muni Chandra; Reddy, Netala Vasudeva; Rajendra, Wudayagiri

2016-01-01

Emerging drug resistance in clinical isolates of Staphylococcus aureus might be implicated to the overexpression of NorA efflux pump which is capable of extruding numerous structurally diverse compounds. However, NorA efflux pump is considered as a potential drug target for the development of efflux pump inhibitors. In the present study, NorA model was constructed based on the crystal structure of glycerol-3-phosphate transporter (PDBID: 1PW4). Molecular dynamics (MD) simulation was performed using NAMD2.7 for NorA which is embedded in the hydrated lipid bilayer. Structural design of NorA unveils amino (N)- and carboxyl (C)-terminal domains which are connected by long cytoplasmic loop. N and C domains are composed of six transmembrane α-helices (TM) which exhibits pseudo-twofold symmetry and possess voluminous substrate binding cavity between TM helices. Molecular docking of reserpine, totarol, ferruginol, salvin, thioxanthene, phenothiazine, omeprazole, verapamil, nalidixic acid, ciprofloxacin, levofloxacin, and acridine to NorA found that all the molecules were bound at the large hydrophobic cleft and indicated significant interactions with the key residues. In addition, structure-based virtual screening was employed which indicates that 14 potent novel lead molecules such as CID58685302, CID58685367, CID5799283, CID5578487, CID60028372, ZINC12196383, ZINC72140751, ZINC72137843, ZINC39227983, ZINC43742707, ZINC12196375, ZINC66166948, ZINC39228014, and ZINC14616160 have highest binding affinity for NorA. These lead molecules displayed considerable pharmacological properties as evidenced by Lipinski rule of five and prophecy of toxicity risk assessment. Thus, the present study will be helpful in designing and synthesis of a novel class of NorA efflux pump inhibitors that restore the susceptibilities of drug compounds.

SIMS depth profiling of rubber-tyre cord bonding layers prepared using 64Zn depleted ZnO

NASA Astrophysics Data System (ADS)

Fulton, W. S.; Sykes, D. E.; Smith, G. C.

2006-07-01

Zinc oxide and copper/zinc sulphide layers are formed during vulcanisation and moulding of rubber to brass-coated steel tyre reinforcing cords. Previous studies have described how zinc diffuses through the rubber-brass interface to form zinc sulphide, and combines with oxygen to create zinc oxide during dezincification. The zinc is usually assumed to originate in the brass of the tyre cord, however, zinc oxide is also present in the rubber formulation. We reveal how zinc from these sources is distributed within the interfacial bonding layers, before and after heat and humidity ageing. Zinc oxide produced using 64Zn-isotope depleted zinc was mixed in the rubber formulation in place of the natural ZnO and the zinc isotope ratios within the interfacial layers were followed by secondary ion mass spectroscopy (SIMS) depth profiling. Variations in the relative ratios of the zinc isotopes during depth profiling were measured for unaged, heat-aged and humidity-aged wire samples and in each case a relatively large proportion of the zinc incorporated into the interfacial layer as zinc sulphide was shown to have originated from ZnO in the rubber compound.

Ca2+-exchange in layered zirconium orthophosphate, α-ZrP: Chemical study and potential application for zinc corrosion inhibition

NASA Astrophysics Data System (ADS)

Bouali, Imane; Rocca, Emmanuel; Veys-Renaux, Delphine; Rhouta, Benaissa; Khalil, Aziza; Aït Aghzzaf, Ahmed

2017-11-01

The control of the corrosion phenomenon occurring at the metal interface requires the development of new non-toxic anticorrosion additives. For this purpose, zirconium orthophosphate compounds (Zr(HPO4)2,H2O noted α-ZrP) were synthesized by both hydrothermal and refluxing methods The Ca2+-cationic exchange in the layered structure is kinetically favoured by low crystallinity of α-ZrP synthesized by refluxing process, and leads to the formation of CaZr(PO4)2,4H2O, noted Ca2+-ZrP. The H+/Ca2+ exchange mechanism is mainly triggered by acid-base considerations, and especially the pKa of α-ZrP/Ca2+-ZrP acid-base couple (evaluated to 2.5). Both compounds are acidic compounds by internal exchangeable H+ for α-ZrP and surface protons for Ca2+-ZrP, and can be used as potential inhibitors of zinc corrosion. Electrochemical measurements show that Ca2+-ZrP compounds dispersed in the NaCl electrolyte buffer the pH value over a long time and therefore allow controlling the corrosion rate of zinc.

Directed spatial organization of zinc oxide nanostructures

DOEpatents

Hsu, Julia [Albuquerque, NM; Liu, Jun [Richland, WA

2009-02-17

A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

The Corrosion Protection of 2219-T87 Aluminum by Organic and Inorganic Zinc-Rich Primers

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

1995-01-01

The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 pA/CM2 and 23.7 pA/CM2 for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

The corrosion protection of 2219-T87 aluminum by organic and inorganic zinc-rich primers

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

1995-01-01

The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electro-chemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. the galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 micro A/cm(exp 2) and 23.7 micro A/cm(exp 2) for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.

1995-01-01

The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

X-ray Absorption Spectroscopy Combined with Time-Dependent Density Functional Theory Elucidates Differential Substitution Pathways of Au(I) and Au(III) with Zinc Fingers.

PubMed

Abbehausen, Camilla; de Paiva, Raphael Enoque Ferraz; Bjornsson, Ragnar; Gomes, Saulo Quintana; Du, Zhifeng; Corbi, Pedro Paulo; Lima, Frederico Alves; Farrell, Nicholas

2018-01-02

A combination of two elements' (Au, Zn) X-ray absorption spectroscopy (XAS) and time-dependent density functional theory (TD-DFT) allowed the elucidation of differential substitution pathways of Au(I) and Au(III) compounds reacting with biologically relevant zinc fingers (ZnFs). Gold L 3 -edge XAS probed the interaction of gold and the C-terminal Cys 2 HisCys finger of the HIV-1 nucleocapsid protein NCp7, and the Cys 2 His 2 human transcription factor Sp1. The use of model compounds helped assign oxidation states and the identity of the gold-bound ligands. The computational studies accurately reproduced the experimental XAS spectra and allowed the proposition of structural models for the interaction products at early time points. The direct electrophilic attack on the ZnF by the highly thiophilic Au(I) resulted in a linear P-Au-Cys coordination sphere after zinc ejection whereas for the Sp1, loss of PEt 3 results in linear Cys-Au-Cys or Cys-Au-His arrangements. Reactions with Au(III) compounds, on the other hand, showed multiple binding modes. Prompt reaction between [AuCl(dien)] 2+ and [Au(dien)(DMAP)] 3+ with Sp1 showed a partially reduced Au center and a final linear His-Au-His coordination. Differently, in the presence of NCp7, [AuCl(dien)] 2+ readily reduces to Au(I) and changes from square-planar to linear geometry with Cys-Au-His coordination, while [Au(dien)(DMAP)] 3+ initially maintains its Au(III) oxidation state and square-planar geometry and the same first coordination sphere. The latter is the first observation of a "noncovalent" interaction of a Au(III) complex with a zinc finger and confirms early hypotheses that stabilization of Au(III) occurs with N-donor ligands. Modification of the zinc coordination sphere, suggesting full or partial zinc ejection, is observed in all cases, and for [Au(dien)(DMAP)] 3+ this represents a novel mechanism for nucleocapsid inactivation. The combination of XAS and TD-DFT presents the first direct experimental observation that not only compound reactivity, but also ZnF core specificity, can be modulated on the basis of the coordination sphere of Au(III) compounds.

Structural and thermomechanical properties of the zinc-blende AlX (X = P, As, Sb) compounds

NASA Astrophysics Data System (ADS)

Ha, Vu Thi Thanh; Hung, Vu Van; Hanh, Pham Thi Minh; Nguyen, Viet Tuyen; Hieu, Ho Khac

2017-08-01

The structural and thermomechanical properties of zinc-blende aluminum class of III-V compounds have been studied based on the statistical moment method (SMM) in quantum statistical mechanics. Within the SMM scheme, we derived the analytical expressions of the nearest-neighbor distance, thermal expansion coefficient, atomic mean-square displacement and elastic moduli (Young’s modulus, bulk modulus and shear modulus). Numerical calculations have been performed for zinc-blende AlX (X = As, P, Sb) at ambient conditions up to the temperature of 1000 K. Our results are in good and reasonable agreements with earlier measurements and can provide useful references for future experimental and theoretical works. This research presents a systematic approach to investigate the thermodynamic and mechanical properties of materials.

Morphological Control of Metal Oxide-Doped Zinc Oxide and Application to Cosmetics

NASA Astrophysics Data System (ADS)

Goto, Takehiro; Yin, Shu; Sato, Tsugio; Tanaka, Takumi

2012-06-01

Zinc oxide shows excellent transparency and ultraviolet radiation shielding ability, and is used for various cosmetics.1-3 However, it possesses high catalytic activity and lower dispersibility. Therefore, spherical particles of zinc oxide have been synthesized by soft solution reaction using zinc nitrate, ethylene glycol, sodium hydroxide and triethanolamine as starting materials. After dissolving these compounds in water, the solution was heated at 90°C for 1 h to form almost mono-dispersed spherical zinc oxide particles. The particle size changed depending on zinc ion concentration, ethylene glycol concentration and so on. Furthermore, with doping some metal ions, the phtocatalytic activity could be decreased. The obtained monodispersed metal ion-doped spherical zinc oxides showed excellent UV shielding ability and low photocatalytic activity. Therefore, they are expected to be used as cosmetics ingredients.

Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

PubMed

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2016-04-25

Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

Investigation into the role of primer, pre-treatments and coating microstructure in preventing cut edge corrosion of organically coated steels

NASA Astrophysics Data System (ADS)

Khan, Khalil

Investigations were carried out to assess the role of primer, pretreatments and coating microstructure in preventing cutedge corrosion of chrome free organically coated steels. Zinc runoff was monitored from a range of organically coated steels with a large cutedge length exposed over 18 months at Swansea University roof top site. The zinc in the runoff leaches from the zinc-aluminium alloy coating of the substrate. The paint systems' corrosion performance was assessed by monitoring the levels of zinc in the runoff. Consequently the levels of zinc reflected the effectiveness of the applied paint system against corrosion. Runoff was high in initial months with zinc levels reducing with time due to the build up of corrosion products that hindered the progress of corrosion. An accelerated laboratory test using a distilled water electrolyte was developed that predict long-term external weathering runoff from panels of a range of organically coated steels. The corrosion mechanisms of a variety of organically coated Galvalloy steel have been examined using the scanning vibrating electrode technique (SVET) in 0.1%NaCI. The corrosion behaviour of a coating is related to the zinc-aluminium alloy coating structure and combination of pretreatment and primer. The SVET has been used to assess total zinc loss and the corrosion rate for a comparative measure of organically coating system performance. A correlation has been developed from SVET 24hour experiment data to accelerated weathering data and external weather data that can aid more accurately predicting the in service life of the product. Also considered were the effects of electrolyte conductivity on the morphology of corrosion on pure zinc. A mathematical model has been developed to predict corrosion pit population. Altered microstructure of solidifying zinc aluminium alloy melt via ultrasonication was investigated. Ultrasound irradiation significantly altered the final microstructure. The influence of morphed microstructure upon the corrosion behaviour was explored using the SVET in 0.1%NaCI. The ultrasound manipulated microstructure had generally a positive effect on the corrosion behaviour.

Sonocatalytic degradation of malachite green oxalate by a semiconductor metal oxide nanocatalyst.

PubMed

Bhavani, R; Sivasamy, A

2016-12-01

Advanced Oxidation Process (AOP) technologies are considered to be better technique for the degradation or mineralization of many recalcitrant compounds and pollutants. In the present study heterogeneous sonocatalytic degradation of a model organic compound such as Malachite green oxalate (MGO) was carried out in the aqueous phase. Zinc oxide nanorods were prepared by precipitation method employing zinc acetates as precursors and were characterized by FT-IR, XRD, FE-SEM and EDAX analysis. Degradation of MGO in the aqueous phase was studied in detail under the sonocatalytic process. Effects of pH, dye concentration, oxidant concentration, kinetics and effect of electrolytes on dye degradation were carried out to check the efficiency of the sonocatalyst. Effect of energy input on the degradation processes was also investigated. The degradation of dye molecules were monitored by UV-visible spectrophotometer and Chemical Oxygen demand (COD). The dye molecules were readily degraded at above 90% in the pH range 5.0-7.0 under ultrasound with zinc oxide nanorods. The interference of electrolytes like NaCl, KCl, Na 2 CO 3 , NaHCO 3 and MgSO 4 on the degradation of dye molecules were also studied on the sonocatalytic degradation of MGO. From the kinetic studies it was observed that at lower initial concentration of dye molecules the degradation efficiency was above 90%. The rate of the reaction decreased on increasing the initial dye concentrations of the dye molecules. It was observed that the complete mineralization of dye molecules was achieved without the formation of toxic by-products. The reusability of the catalyst also showed the effective degradation of the dye molecules up to five cycles without loss of the catalytic activities. Copyright © 2015 Elsevier Inc. All rights reserved.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

NASA Astrophysics Data System (ADS)

Matinise, N.; Fuku, X. G.; Kaviyarasu, K.; Mayedwa, N.; Maaza, M.

2017-06-01

The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV-vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Final expanded site inspection, ammunition storage area, Anniston Army Depot, Anniston, Alabama. Final report, September 1992-November 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suomela, K.D.; Highsmith, R.L.; Rapuano, K.F.

1994-11-15

An Expanded Site Inspection (ESI) was conducted at the Anniston Army Depot (ANAD) Ammunition Storage Area (ASA). The objective of this ESI was to gather the information and data necessary to determine whether there is sufficient evidence of any release of contamination that would require additional investigation. The ASA contains 1,300 ammunition storage magazines and an ammunition maintenance workshop complex which includes buildings for maintenance, demilitarization, and inspection of all types of ammunition and their components. Fifteen Solid Waste Management Units (SWMUs) were the focus of the ESI, of which 11 were recommend for further investigation. The work included amore » review of historical records, field investigations, laboratory analyses, data interpretation, and report preparation. Contamination from volatile organic compounds and semi volatile organic compounds is not a major problem at the ASA. Arsenic, beryllium, cadmium, chromium, lead, mercury, nickel, silver, vanadium, zinc, explosives, and total petroleum hydrocarbons were detected above control screening values levels in one or more of the media sampled. Nitrate/nitrite and total organic carbon were also detected above control screening values in samples of groundwater, soil, and sediment from a number of SWMUs.« less

31P-edited diffusion-ordered 1H NMR spectroscopy for the spectral isolation and identification of organophosphorus compounds related to chemical weapons agents and their degradation products.

PubMed

Mayer, Brian P; Valdez, Carlos A; Hok, Saphon; Chinn, Sarah C; Hart, Bradley R

2012-12-04

Organophosphorus compounds represent a large class of molecules that include pesticides, flame-retardants, biologically relevant molecules, and chemical weapons agents (CWAs). The detection and identification of organophosphorus molecules, particularly in the cases of pesticides and CWAs, are paramount to the verification of international treaties by various organizations. To that end, novel analytical methodologies that can provide additional support to traditional analyses are important for unambiguous identification of these compounds. We have developed an NMR method that selectively edits for organophosphorus compounds via (31)P-(1)H heteronuclear single quantum correlation (HSQC) and provides an additional chromatographic-like separation based on self-diffusivities of the individual species via (1)H diffusion-ordered spectroscopy (DOSY): (1)H-(31)P HSQC-DOSY. The technique is first validated using the CWA VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate) by traditional two-dimensional DOSY spectra. We then extend this technique to a complex mixture of VX degradation products and identify all the main phosphorus-containing byproducts generated after exposure to a zinc-cyclen organometallic homogeneous catalyst.

Phenolics and essential mineral profile of organic acid pretreated unripe banana flour.

PubMed

Anyasi, Tonna A; Jideani, Afam I O; Mchau, Godwin R A

2018-02-01

Banana fruit (Musa spp) though rich in essential minerals, has also been implicated for the presence of phytochemicals which nonetheless beneficial, can also act as mineral inhibitors when in forms such as phenolic compounds, phytates and tannins. This study assayed the essential macro and trace minerals as well as phenolic compounds present in unripe banana flour (UBF) obtained from the pulp of four different cultivars. Unripe banana flour was processed by oven drying in a forced air oven dryer at 70°C upon pretreatment with ascorbic, citric and lactic acid. Organic acid pretreatment was done separately on each unripe banana cultivar at concentrations of 10, 15 and 20g/L. Phenolic compounds were profiled using liquid chromatography mass spectrometry electrospray ion (LC-MS-ESI) while essential minerals were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectroscopy (ICP-MS) respectively. Results of LC-MS-ESI assay of phenolics revealed the presence of flavonoids: epicatechin and myricetin 3-O-rhamnosyl-glucoside in varying concentrations in UBF. Essential mineral profile indicated that Zinc had the least occurrence of 3.55mg/kg (p<0.05), while potassium was the most abundant mineral at 14746.73mg/kg in UBF of all four banana cultivars. Correlation between phenolic compounds and essential minerals using Pearson's Correlation Coefficient test revealed weak and inverse association between flavonoids and most macro and trace minerals present in UBF samples. Organic acid pretreatment thus exhibited little effect on phenolics and essential minerals of UBF samples, though, inhibitory influence of phenolic compounds was recorded on essential minerals. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Utilization of household organic compost in zinc adsorption system

NASA Astrophysics Data System (ADS)

Cundari, Lia; Isvaringga, Nyiayu Dita; Arinda, Yesica Maharani

2017-11-01

Zinc (Zn) is one of the heavy metals which is polluted to the environment in an amount greater than 15 mg/L [1]. Zinc contamination caused by the disposal of industrial waste such as batteries, electroplating, paint and other industries. One of the Zinc recovery technique that is relatively inexpensive, simple, high effectiveness and efficiency, and can be regenerated is adsorption using compost. This study has been carried out the preparation of compost from organic household waste and cow manure and its application to Zinc recovery. In this research, the raw material of compost is varied. There is an organic household waste (A1) and a mixture of organic household waste and cow manure with ratio 7:6 (A2). Decomposition of A1 and A2 with addition Effective Microorganism (EM4) requires 21 days, with 3 times inversion. Zinc adsorption is done by using a compost variation of 0.5 g, 1 g, and 2 g in every 100 and 200 mg/L Zn concentration solution. The batch process is applied to analyze the capacity of adsorption. Determination of capacity of adsorption based on the Langmuir, Freundlich, and Temkin isotherm model. Direct observation and spectrophotometry are applied in research methodology. The results show that compost A1 and A2 have fulfilled Indonesian Standart of compost and have the ability to reduce Zinc concentration to 94-96%. It indicates highly recommended biosorbent that can be applied to Zinc adsorption.

Cytidine derivatives as IspF inhibitors of Burkolderia pseudomallei

PubMed Central

Zhang, Zheng; Jakkaraju, Sriram; Blain, Joy; Gogol, Kenneth; Zhao, Lei; Hartley, Robert C.; Karlsson, Courtney A.; Staker, Bart L.; Stewart, Lance J.; Myler, Peter J.; Clare, Michael; Begley, Darren W.; Horn, James R.; Hagen, Timothy J

2013-01-01

Published biological data suggest that the methyl erythritol phosphate (MEP) pathway, a non-mevalonate isoprenoid biosynthetic pathway, is essential for certain bacteria and other infectious disease organisms. One highly conserved enzyme in the MEP pathway is 2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (IspF). Fragment-bound complexes of IspF from Burkholderia pseudomallei were used to design and synthesize a series of molecules linking the cytidine moiety to different zinc pocket fragment binders. Testing by surface plasmon resonance (SPR) found one molecule in the series to possess binding affinity equal to that of cytidine diphosphate, despite lacking any metal-coordinating phosphate groups. Close inspection of the SPR data suggest different binding stoichiometries between IspF and test compounds. Crystallographic analysis shows important variations between the binding mode of one synthesized compound and the pose of the bound fragment from which it was designed. The binding modes of these molecules add to our structural knowledge base for IspF and suggest future refinements in this compound series. PMID:24157367

Synthesis and self-organization of zinc β-(dialkoxyphosphoryl)porphyrins in the solid state and in solution.

PubMed

Vinogradova, Ekaterina V; Enakieva, Yulia Y; Nefedov, Sergey E; Birin, Kirill P; Tsivadze, Aslan Y; Gorbunova, Yulia G; Bessmertnykh Lemeune, Alla G; Stern, Christine; Guilard, Roger

2012-11-19

The first synthesis and self-organization of zinc β-phosphorylporphyrins in the solid state and in solution are reported. β-Dialkoxyphosphoryl-5,10,15,20-tetraphenylporphyrins and their Zn(II) complexes have been synthesized in good yields by using Pd- and Cu-mediated carbon-phosphorous bond-forming reactions. The Cu-mediated reaction allowed to prepare the mono-β-(dialkoxyphosphoryl)porphyrins 1 Zn-3 Zn starting from the β-bromo-substituted zinc porphyrinate ZnTPPBr (TPP = tetraphenylporphyrin) and dialkyl phosphites HP(O)(OR)(2) (R = Et, iPr, nBu). The derivatives 1 Zn-3 Zn were obtained in good yields by using one to three equivalents of CuI. When the reaction was carried out in the presence of catalytic amounts of palladium complexes in toluene, the desired zinc derivative 1 Zn was obtained in up to 72% yield. The use of a Pd-catalyzed C-P bond-forming reaction was further extended to the synthesis of β-poly(dialkoxyphosphoryl)porphyrins. An unprecedented one-pot sequence involving consecutive reduction and phosphorylation of H(2)TPPBr(4) led to the formation of a mixture of the 2,12- and 2,13-bis(dialkoxy)phosphorylporphyrins 5 H(2) and 6 H(2) in 81% total yield. According to the X-ray diffraction studies, 1 Zn and 3 Zn are partially overlapped cofacial dimers formed through the coordination of two Zn centers by two phosphoryl groups belonging to the adjacent molecules. The equilibrium between the monomeric and the dimeric species exists in solutions of 1 Zn and 3 Zn in weakly polar solvents according to spectroscopic data (UV/Vis absorption and NMR spectroscopy). The ratio of each form is dependent on the concentration, temperature, and traces of water or methanol. These features demonstrated that zinc β-phosphorylporphyrins can be regarded as new model compounds for the weakly coupled chlorophyll pair in the photosynthesis process. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Occurrence and distribution of contaminants in bottom sediment and water of the Barron River Canal, Big Cypress National Preserve, Florida

USGS Publications Warehouse

Miller, Ronald L.; McPherson, Benjamin F.

2001-01-01

Trace elements and organic contaminants in bottom-sediment samples collected from 10 sites on the Barron River Canal and from one site on the Turner River in October 1998 had patterns of distribution that indicated different sources. At some sites on the Barron River Canal, lead, copper, and zinc, normalized to aluminum, exceeded limits normally considered as background and may be enriched by human activities. Polynuclear aromatic hydrocarbons and p-cresol, normalized against organic carbon, had patterns of distribution that indicated local sources of input from a road or vehicular traffic or from an old creosote wood treatment facility. Phthalate esters and the traces elements arsenic, cadmium, and zinc were more widely distributed with the highest normalized concentrations occurring at the Turner River background site, probably due to the high percentage of fine sediment (74% less than 63 micrometers) and high organic carbon concentration (42%) at that site and the binding effect of organic carbon on trace elements and trace organic compounds. Low concentrations of pesticides or pesticide degradation products were detected in bottom sediment (DDD and DDE, each less than 3.5 µg/kg) and water (9 pesticides, each less than 0.06 µ/L), primarily in the northern reach of the Barron River Canal where agriculture is a likely source. Although a few contaminants approached criteria that would indicate adverse effects on aquatic life, none exceeded the criteria, but the potential synergistic effects of mixtures of contaminants found at most sites are not included in the criteria.

Steric Effects on the Binding of Phosphate and Polyphosphate Anions by Zinc(II) and Copper(II) Dinuclear Complexes of m-Xylyl-bis-cyclen.

PubMed

Esteves, Catarina V; Esteban-Gómez, David; Platas-Iglesias, Carlos; Tripier, Raphaël; Delgado, Rita

2018-05-11

The triethylbenzene-bis-cyclen (cyclen = 1,4,7,10-tetraazacyclododecane) compound (tbmce) was designed with an imposed structural rigidity at the m-xylyl spacer to be compared to a less restrained and known parent compound (bmce). The framework of both compounds differs only in the substituents of the m-xylyl spacer. The study was centered in the differences observed in the acid-base reactions of both compounds, their copper(II) and zinc(II) complexation behaviors, as well as in the uptake of phosphate and polyphosphate anions (HPPi 3- , ATP 4- , ADP 3- , AMP 2- , PhPO 4 2- , and HPO 4 2- ). On the one hand, the acid-base reactions showed lower values for the third and fourth protonation constants of tbmce than for bmce, suggesting that the ethyl groups of the spacer in tbmce force the two cyclen units to more conformational restricted positions. On the other hand, the stability constant values for copper(II) and zinc(II) complexes revealed that bmce is a better chelator than tbmce pointing out to additional conformational restraints imposed by the triethylbenzene spacer. The binding studies of phosphates by the dinuclear copper(II) and zinc(II) complexes showed much smaller effective association constants for the dicopper complexes. Single-crystal X-ray and computational (density functional theory) studies suggest that anion binding promotes the formation of tetranuclear entities in which anions are bridging the metal centers. Our studies also revealed the dinuclear zinc(II) complex of bmce as a promising receptor for phosphate anions, with the largest effective association constant of 5.94 log units being observed for the formation of [Zn 2 bmce(HPPi)] + . Accordingly, a colorimetric study via an indicator displacement assay to detect phosphates in aqueous solution found that the [Zn 2 bmce] 4+ complex acts as the best receptor for pyrophosphate displaying a detection limit of 2.5 nM by changes visible to naked eye.

Evaluation of the Multi-Chambered Treatment Train, a retrofit water-quality management device

USGS Publications Warehouse

Corsi, Steven R.; Greb, Steven R.; Bannerman, Roger T.; Pitt, Robert E.

1999-01-01

This paper presents the results of an evaluation of the benefits and efficiencies of a device called the Multi-Chambered Treatment Train (MCTT), which was installed below the pavement surface at a municipal maintenance garage and parking facility in Milwaukee, Wisconsin. Flow-weighted water samples were collected at the inlet and outlet of the device during 15 storms, and the efficiency of the device was based on reductions in the loads of 68 chemical constituents and organic compounds. High reduction efficiencies were achieved for all particulate-associated constituents, including total suspended solids (98 percent), total phosphorus (88 percent), and total recoverable zinc (91 percent). Reduction rates for dissolved fractions of the constituents were substantial, but somewhat lower (dissolved solids, 13 percent; dissolved phosphorus, 78 percent; dissolved zinc, 68 percent). The total dissolved solids load, which originated from road salt storage, was more than four times the total suspended solids load. No appreciable difference was detected between particle-size distributions in inflow and outflow samples.

A novel bioassay for evaluating the efficacy of biocides to inhibit settling and early establishment of marine biofilms.

PubMed

Arrhenius, Åsa; Backhaus, Thomas; Hilvarsson, Annelie; Wendt, Ida; Zgrundo, Aleksandra; Blanck, Hans

2014-10-15

This paper presents a novel assay that allows a quick and robust assessment of the effects of biocides on the initial settling and establishment of marine photoautotrophic biofilms including the multitude of indigenous fouling organisms. Briefly, biofilms are established in the field, sampled, comminuted and re-settled on clean surfaces, after 72h chlorophyll a is measured as an integrating endpoint to reflect both settling and growth. Eight antifoulants were used to evaluate the assay. Efficacy ranking, based on EC98 values from most to least efficacious compound is: copper pyrithione>TPBP>DCOIT>tolylfluanid>zinc pyrithione>medetomidine>copper (Cu(2+)), while ecotoxicological ranking (based on EC10 values) is irgarol, copper pyrithione>zinc pyrithione>TPBP>tolylfluanid>DCOIT>copper (Cu(2+))>medetomidine. The algaecide irgarol did not cause full inhibition. Instead the inhibition leveled out at 95% effect at 30 nmoll(-)(1), a concentration that was clearly lower than for any other of the tested biocides. Copyright © 2014. Published by Elsevier Ltd.

Procaspase-activating compound 1 induces a caspase-3-dependent cell death in cerebellar granule neurons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aziz, Gulzeb; Akselsen, Oyvind W.; Hansen, Trond V.

2010-09-15

Procaspase-activating compound 1, PAC-1, has been introduced as a direct activator of procaspase-3 and has been suggested as a therapeutic agent against cancer. Its activation of procaspase-3 is dependent on the chelation of zinc. We have tested PAC-1 and an analogue of PAC-1 as zinc chelators in vitro as well as their ability to activate caspase-3 and induce cell death in chicken cerebellar granule neuron cultures. These neurons are non-dividing, primary cells with normal caspase-3. The results reported herein show that PAC-1 chelates zinc, activates procaspase-3, and leads to caspase-3-dependent cell death in neurons, as the specific caspase-3-inhibitor Ac-DEVD-cmk inhibitedmore » both the caspase-3 activity and cell death. Thus, chicken cerebellar granule neurons is a suitable model to study mechanisms of interference with apoptosis of PAC-1 and similar compounds. Furthermore, the present study also raises concern about potential neurotoxicity of PAC-1 if used in cancer therapy.« less

Zinc Absorption by Young Adults from Supplemental Zinc Citrate Is Comparable with That from Zinc Gluconate and Higher than from Zinc Oxide123

PubMed Central

Wegmüller, Rita; Tay, Fabian; Zeder, Christophe; Brnić, Marica; Hurrell, Richard F.

2014-01-01

The water-soluble zinc salts gluconate, sulfate, and acetate are commonly used as supplements in tablet or syrup form to prevent zinc deficiency and to treat diarrhea in children in combination with oral rehydration. Zinc citrate is an alternative compound with high zinc content, slightly soluble in water, which has better sensory properties in syrups but no absorption data in humans. We used the double-isotope tracer method with 67Zn and 70Zn to measure zinc absorption from zinc citrate given as supplements containing 10 mg of zinc to 15 healthy adults without food and compared absorption with that from zinc gluconate and zinc oxide (insoluble in water) using a randomized, double-masked, 3-way crossover design. Median (IQR) fractional absorption of zinc from zinc citrate was 61.3% (56.6–71.0) and was not different from that from zinc gluconate with 60.9% (50.6–71.7). Absorption from zinc oxide at 49.9% (40.9–57.7) was significantly lower than from both other supplements (P < 0.01). Three participants had little or no absorption from zinc oxide. We conclude that zinc citrate, given as a supplement without food, is as well absorbed by healthy adults as zinc gluconate and may thus be a useful alternative for preventing zinc deficiency and treating diarrhea. The more insoluble zinc oxide is less well absorbed when given as a supplement without food and may be minimally absorbed by some individuals. This trial was registered at clinicaltrials.gov as NCT01576627. PMID:24259556

The Potential for Zinc Stable Isotope Techniques and Modelling to Determine Optimal Zinc Supplementation

PubMed Central

Tran, Cuong D.; Gopalsamy, Geetha L.; Mortimer, Elissa K.; Young, Graeme P.

2015-01-01

It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease. PMID:26035248

Chemical vapor deposition of fluorine-doped zinc oxide

DOEpatents

Gordon, Roy G.; Kramer, Keith; Liang, Haifan

2000-06-06

Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

The application of bioactive compounds from the food industry to control mold growth in indoor waterborne coatings.

PubMed

Bellotti, N; Salvatore, L; Deyá, C; Del Panno, M T; del Amo, B; Romagnoli, R

2013-04-01

Microbial growth in indoor environments creates health problems, especially in people with asthma; approximately 80% of these patients are allergic to mold. Antimicrobial coatings are formulated to generate surfaces that are easy to clean and may also incorporate active agents, commonly called biocides, which inhibit microbial colonization, subsequent growth and bio-deterioration of the substrates. Some research lines seek to replace traditional organometallic and organochlorines biocides with environmentally acceptable ones. The aim of this research was, primarily, to explore the possible application of different compounds used in food industry like preservatives to be used as antimicrobial additives for antimicrobial coatings. Four biocides were tested against two different ambient molds isolated from an interior painted wall (Chaetomium globosum and Alternaria alternate). The selected biocides were zinc salicylate, zinc benzoate, calcium benzoate and potassium sorbate. The resulting paints were subjected to biological and physical tests (viscosity, hiding power, humidity absorption and biocides leaching rate). Bioassays revealed that zinc benzoate and zinc salicylate resulted active against both fungi. Copyright © 2012 Elsevier B.V. All rights reserved.

The effect of various zinc binding groups on inhibition of histone deacetylases 1-11.

PubMed

Madsen, Andreas S; Kristensen, Helle M E; Lanz, Gyrithe; Olsen, Christian A

2014-03-01

Histone deacetylases (HDACs) have the ability to cleave the acetyl groups of ε-N-acetylated lysine residues in a variety of proteins. Given that human cells contain thousands of different acetylated lysine residues, HDACS may regulate a wide variety of processes including some implicated in conditions such as cancer and neurodegenerative disorders. Herein we report the synthesis and in vitro biochemical profiling of a series of compounds, including known inhibitors as well as novel chemotypes, that incorporate putative new zinc binding domains. By evaluating the compound collection against all 11 recombinant human HDACs, we found that the trifluoromethyl ketone functionality provides potent inhibition of all four subclasses of the Zn(2+) -dependent HDACs. Potent inhibition was observed with two different scaffolds, demonstrating the efficiency of the trifluoromethyl ketone moiety as a zinc binding motif. Interestingly, we also identified silanediol as a zinc binding group with potential for future development of non-hydroxamate class I and class IIb HDAC inhibitors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acute oral toxicity and biodistribution study of zinc-aluminium-levodopa nanocomposite

NASA Astrophysics Data System (ADS)

Kura, Aminu Umar; Saifullah, Bullo; Cheah, Pike-See; Hussein, Mohd Zobir; Azmi, Norazrina; Fakurazi, Sharida

2015-03-01

Layered double hydroxide (LDH) is an inorganic-organic nano-layered material that harbours drug between its two-layered sheets, forming a sandwich-like structure. It is attracting a great deal of attention as an alternative drug delivery (nanodelivery) system in the field of pharmacology due to their relative low toxic potential. The production of these nanodelivery systems, aimed at improving human health through decrease toxicity, targeted delivery of the active compound to areas of interest with sustained release ability. In this study, we administered zinc-aluminium-LDH-levodopa nanocomposite (ZAL) and zinc-aluminium nanocomposite (ZA) to Sprague Dawley rats to evaluate for acute oral toxicity following OECD guidelines. The oral administration of ZAL and ZA at a limit dose of 2,000 mg/kg produced neither mortality nor acute toxic signs throughout 14 days of the observation. The percentage of body weight gain of the animals showed no significant difference between control and treatment groups. Animal from the two treated groups gained weight continuously over the study period, which was shown to be significantly higher than the weight at the beginning of the study ( P < 0.05). Biochemical analysis of animal serum showed no significant difference between rats treated with ZAL, ZA and controls. There was no gross lesion or histopathological changes observed in vital organs of the rats. The results suggested that ZAL and ZA at 2,000 mg/kg body weight in rats do not induce acute toxicity in the animals. Elemental analysis of tissues of treated animals demonstrated the wider distribution of the nanocomposite including the brain. In summary, findings of acute toxicity tests in this study suggest that zinc-aluminium nanocomposite intercalated with and the un-intercalated were safe when administered orally in animal models for short periods of time. It also highlighted the potential distribution ability of Tween-80 coated nanocomposite after oral administration.

Evaluation of solubility in simulated lung fluid of metals present in the slag from a metallurgical industry to produce metallic zinc.

PubMed

Lima, Rosilda M G; Carneiro, Luana G; Afonso, Júlio C; Cunha, Kenya M D

2013-01-01

The objective of this study was to determine the solubility parameters (rapid and slow dissolution rates, rapid and slow dissolution fractions) for nickel, cadmium, zinc and manganese compounds present in a pile of slag accumulated under exposure to weathering. This slag was generated by a metallurgical industry that produced zinc and zinc alloys from hemimorphite (Zn(4)(OH)(2)Si(2)O(7).H(2)O) and willemite (Zn(2)SiO(4)) minerals. A static dissolution test in vitro was used to determine the solubility parameters and Gamble's solution was used as the simulated lung fluid (SLF), on a time basis ranging from 10 min to 1 year. The metal concentrations in the slag samples and in the SLF were determined using Particle Induced X-rays Emission (PIXE). There are significant differences in terms of solubility parameters among the metals. The results indicated that the zinc, nickel, cadmium and manganese compounds present in the slag were moderately soluble in the SLF. The rapid dissolution fractions of these metals are associated with their sulfates. In conclusion, this study confirms the harmful effects on the neighboring population of the airborne particles containing these metals that came from the slag.

Synthesis and biological evaluation of Santacruzamate-A based analogues.

PubMed

Randino, Rosario; Gazzerro, Patrizia; Mazitschek, Ralph; Rodriquez, Manuela

2017-12-15

Several derivatives of Santacruzamate-A, a natural product that is structurally related to SAHA, were synthesized to explore the potential of carbamates and oxalylamides as novel biasing element for targeting the catalytic site of zinc-dependent histone deacetylases (HDACs). An additional class of Santacruzamate-A derivatives was synthesized to investigate the influence of the cap group and the linker element on HDAC inhibitory activity. All compounds were evaluated in dose response for their in vitro cytotoxic activity in MTT assay in HCT116 cells. HDAC inhibitory activity was evaluated in vitro by western blot analysis for histone hyperacetylation assay and biochemically for representative human HDACs isoforms. Two novel compounds were identified to exhibit potent time dependent anti proliferative activity. However, unlike hydroxamic acid analogues, the tested Santacruzamate-A derivatives showed no noticeable HDAC inhibitory activity. The ethylcarbamate moiety as unusual zinc-binding group displayed no ability to coordinate the zinc ion and thus, presumably, was not able to reproduce known inhibitor-substrate zinc-binding group interactions with the HDAC catalytic site. This study confirmed that the accommodation of the zinc-binding group is deeply critical of the positioning of the linker and the projection of the cap group toward the different surface pockets of the enzyme. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Effect of cultivation in zinc media on the growth of and the degree of zinc in organic form in transgenic metallothionein mushroom].

PubMed

Sheng, Ji-Ping; Shen, Lin; Ru, Bing-Gen

2009-03-01

Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich and metal-binding functional proteins. Transgenic MT mushroom can be used as functional food additives, but its zinc-enriching ability has not been studied systemically until now. The zinc contents in mycelia of transgenic MT mushroom (Pleurotus ostreatus) and wild type mushroom mycelia cultivated in different zinc concentration media were analyzed by ICP-OES. The growth status, zinc-enriching ability and degree of zinc in organic form (DZOF) were also analyzed. Results showed that MT mushroom mycelia grew rapidly, but the growth was inhibited when the zinc content in solid media was higher than 1.6 mmol x L(-1). MT mushroom mycelia could enrich more zinc than that of wild type, and the zinc content in MT mushroom mycelia could be 2.56-27.49 mg x kg(-1) when it was cultivated in a liquid media with 0.6-1.2 mmol x L(-1) zinc. DZOF of MT mushroom mycelia in a liquid media with 0.6 mmol x L(-1) zinc at 7 d was significantly higher (88.7%) than that in the wild type (82.1%, alpha = 0.05), but there was no significant difference in DZOF when the MT mushroom mycelia was cultivated in a liquid media with different zinc content at 7 d.

Thermal treatment of solid residues from WtE units: a review.

PubMed

Lindberg, Daniel; Molin, Camilla; Hupa, Mikko

2015-03-01

Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxic organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field. Copyright © 2015 Elsevier Ltd. All rights reserved.

Water-Quality Conditions of Chester Creek, Anchorage, Alaska, 1998-2001

USGS Publications Warehouse

Glass, Roy L.; Ourso, Robert T.

2006-01-01

Between October 1998 and September 2001, the U.S. Geological Survey's National Water-Quality Assessment Program evaluated the water-quality conditions of Chester Creek, a stream draining forest and urban settings in Anchorage, Alaska. Data collection included water, streambed sediments, lakebed sediments, and aquatic organisms samples from urban sites along the stream. Urban land use ranged from less than 1 percent of the basin above the furthest upstream site to 46 percent above the most downstream site. Findings suggest that water quality of Chester Creek declines in the downstream direction and as urbanization in the watershed increases. Water samples were collected monthly and during storms at a site near the stream's mouth (Chester Creek at Arctic Boulevard) and analyzed for major ions and nutrients. Water samples collected during water year 1999 were analyzed for selected pesticides and volatile organic compounds. Concentrations of fecal-indicator bacteria were determined monthly during calendar year 2000. During winter, spring, and summer, four water samples were collected at a site upstream of urban development (South Branch of South Fork Chester Creek at Tank Trail) and five from an intermediate site (South Branch of South Fork Chester Creek at Boniface Parkway). Concentrations of calcium, magnesium, sodium, chloride, and sulfate in water increased in the downstream direction. Nitrate concentrations were similar at the three sites and all were less than the drinking-water standard. About one-quarter of the samples from the Arctic Boulevard site had concentrations of phosphorus that exceeded the U.S. Environmental Protection Agency (USEPA) guideline for preventing nuisance plant growth. Water samples collected at the Arctic Boulevard site contained concentrations of the insecticide carbaryl that exceeded the guideline for protecting aquatic life. Every water sample revealed a low concentration of volatile organic compounds, including benzene, toluene, tetrachloroethylene, methyl tert-butyl ether, and chloroform. No water samples contained volatile organic compounds concentrations that exceeded any USEPA drinking-water standard or guideline. Fecal-indicator bacteria concentrations in water from the Arctic Boulevard site commonly exceeded Federal and State guidelines for water-contact recreation. Concentrations of cadmium, copper, lead, and zinc in streambed sediments increased in the downstream direction. Some concentrations of arsenic, chromium, lead, and zinc in sediments were at levels that can adversely affect aquatic organisms. Analysis of sediment chemistry in successive lakebed-sediment layers from Westchester Lagoon near the stream's mouth provided a record of water-quality trends since about 1970. Concentrations of lead have decreased from peak levels in the mid-1970s, most likely because of removing lead from gasoline and lower lead content in other products. However, concen-trations in recently-deposited lakebed sediments are still about 10 times greater than measured in streambed sediments at the upstream Tank Trail site. Zinc concentrations in lakebed sediments also increased in the early 1970s to levels that exceeded guidelines to protect aquatic life and have remained at elevated but variable levels. Pyrene, benz[a]anthracene, and phenanthrene in lakebed sediments also have varied in concentrations and have exceeded protection guidelines for aquatic life since the 1970s. Concentrations of dichloro-diphenyl-trichloroethane, polychlorinated biphenyls (PCBs), or their by-products generally were highest in lakebed sediments deposited in the 1970s. More recent sediments have concentrations that vary widely and do not show distinct temporal trends. Tissue samples of whole slimy sculpin (Cottus cognatus), a non-migratory species of fish, showed con-centrations of trace elements and organic contaminants. Of the constituents analyzed, only selenium concentra-tions showed levels of potential concern for

Occurrence of Selected Nutrients, Trace Elements, and Organic Compounds in Streambed Sediment in the Lower Chena River Watershed near Fairbanks, Alaska, 2002-03

USGS Publications Warehouse

Kennedy, Ben W.; Hall, Cassidee C.

2009-01-01

In 2002-03, the U.S. Geological Survey collected samples of streambed sediment at 18 sites in the lower Chena River watershed for analysis of selected nutrients, traces elements, and organic compounds. The purpose of the project was to provide Federal, State, and local agencies as well as neighborhood committees, with information for consideration in plans to improve environmental conditions in the watershed. The exploratory sampling program included analysis of streambed sediment from the Chena River and Chena Slough, a tributary to the Chena River. Results were compared to streambed-sediment guidelines for the protection of aquatic life and to 2001-02 sediment data from Noyes Slough, a side channel of the lower Chena River. The median total phosphorus concentration in Chena Slough sediment samples, 680 milligrams per kilogram (mg/kg), was two orders of magnitude greater than median total phosphorus concentration in Chena River sediment samples of 5.2 mg/kg. Median concentrations of chloride and sulfate also were greater in Chena Slough samples. Low concentrations of nitrate were detected in most of the Chena Slough samples; nitrate concentrations were below method reporting limits or not detected in Chena River sediment samples. Streambed-sediment samples were analyzed for 24 trace elements. Arsenic, nickel, and zinc were the only trace elements detected in concentrations that exceeded probable-effect levels for the protection of aquatic life. Concentrations of arsenic in Chena Slough samples ranged from 11 to 70 mg/kg and concentrations in most of the samples exceeded the probable-effect guideline for arsenic of 17 mg/kg. Arsenic concentrations in samples from the Chena River ranged from 9 to 12 mg/kg. The background level for arsenic in the lower Chena River watershed is naturally elevated because of significant concentrations of arsenic in local bedrock and ground water. Sources of elevated concentrations of zinc in one sample, and of nickel in two samples, are unknown. With the exception of elevated arsenic levels in samples from Chena Slough, the occurrence and concentration of trace elements in the streambed sediments of Chena Slough and Chena River were similar to those in Noyes Slough sediment. Sediment samples were analyzed for 78 semivolatile organic compounds and 32 organochlorine pesticides and polychlorinated biphenyls (PCBs). Low concentrations of dimethylnaphthalene and p-Cresol were detected in most Chena Slough and Chena River sediment samples. The number of semivolatile organic compounds detected ranged from 5 to 21 in most Chena Slough sediment samples. In contrast, three or fewer semivolatile organic compounds were detected in Chena River sediment samples, most likely because chemical-matrix interference resulted in elevated reporting limits for organochlorine compounds in the Chena River samples. Low concentrations of fluoranthene, pyrene, and phenanthrene were detected in Chena Slough sediment. Relatively low concentrations of DDT or its degradation products, DDD and DDE, were detected in all Chena Slough samples. Concentrations of total DDT (DDT+DDD+DDE) in two Chena Slough sediment samples exceeded the effectsrange median aquatic-life criteria of 46.1 micrograms per kilogram (ug/kg). DDT concentrations in Chena River streambed-sediment samples were less than 20 ug/kg. Low concentrations of PCB were detected in two Chena Slough streambed-sediment samples. None of the concentrations of the polychlorinated biphenyls or semivolatile organic compounds for which the samples were analyzed exceeded available guidelines for the protection of aquatic life. With the exception of elevated total DDT in two Chena Slough samples, the occurrence and concentration of organochlorine compounds in Chena Slough and Chena River sediment were similar to those in samples collected from Noyes Slough in 2001-02.

Potential ecological risk assessment and predicting zinc accumulation in soils.

PubMed

Baran, Agnieszka; Wieczorek, Jerzy; Mazurek, Ryszard; Urbański, Krzysztof; Klimkowicz-Pawlas, Agnieszka

2018-02-01

The aims of this study were to investigate zinc content in the studied soils; evaluate the efficiency of geostatistics in presenting spatial variability of zinc in the soils; assess bioavailable forms of zinc in the soils and to assess soil-zinc binding ability; and to estimate the potential ecological risk of zinc in soils. The study was conducted in southern Poland, in the Malopolska Province. This area is characterized by a great diversity of geological structures and types of land use and intensity of industrial development. The zinc content was affected by soil factors, and the type of land use (arable lands, grasslands, forests, wastelands). A total of 320 soil samples were characterized in terms of physicochemical properties (texture, pH, organic C content, total and available Zn content). Based on the obtained data, assessment of the ecological risk of zinc was conducted using two methods: potential ecological risk index and hazard quotient. Total Zn content in the soils ranged from 8.27 to 7221 mg kg -1 d.m. Based on the surface semivariograms, the highest variability of zinc in the soils was observed from northwest to southeast. The point sources of Zn contamination were located in the northwestern part of the area, near the mining-metallurgical activity involving processing of zinc and lead ores. These findings were confirmed by the arrangement of semivariogram surfaces and bivariate Moran's correlation coefficients. The content of bioavailable forms of zinc was between 0.05 and 46.19 mg kg -1 d.m. (0.01 mol dm -3 CaCl 2 ), and between 0.03 and 71.54 mg kg -1 d.m. (1 mol dm -3 NH 4 NO 3 ). Forest soils had the highest zinc solubility, followed by arable land, grassland and wasteland. PCA showed that organic C was the key factor to control bioavailability of zinc in the soils. The extreme, very high and medium zinc accumulation was found in 69% of studied soils. There is no ecological risk of zinc to living organisms in the study area, and in 90% of the soils there were no potentially negative effects of zinc to ecological receptors.

Zinc(II) complexes with heterocyclic ether, acid and amide. Crystal structure, spectral, thermal and antibacterial activity studies

NASA Astrophysics Data System (ADS)

Jabłońska-Wawrzycka, Agnieszka; Rogala, Patrycja; Czerwonka, Grzegorz; Hodorowicz, Maciej; Stadnicka, Katarzyna

2016-02-01

The reaction of zinc salts with heterocyclic ether (1-ethoxymethyl-2-methylimidazole (1-ExMe-2-MeIm)), acid (pyridine-2,3-dicarboxylic acid (2,3-pydcH2)) and amide (3,5-dimethylpyrazole-1-carboxamide (3,5-DMePzCONH2)) yielded three new zinc complexes formulated as [Zn(1-ExMe-2-MeIm)2Cl2] 1, fac-[Zn(H2O)6][Zn(2,3-pydcH)3]22 and [Zn(3,5-DMePz)2(NCO)2] 3. Complexes of 1 and 3 are four-coordinated with a tetrahedron as coordination polyhedron. However, compound 2 forms an octahedral cation-anion complex. The complex 3 was prepared by eliminating of the carboxamide group from the ligand and then the 3,5-dimethylpyrazole (3,5-DMePz) and isocyanates formed were employed as new ligands. The IR and X-ray studies have confirmed a bidentate fashion of coordination of the 2,3-pydcH and monodentate fashion of coordination of the 1-ExMe-2-MeIm and 3,5-DMePz to the Zn(II) ions. The crystal packing of Zn(II) complexes are stabilized by intermolecular classical hydrogen bonds of O-H⋯O and N-H⋯O types. The most interesting feature of the supramolecular architecture of complexes is the existence of C-H⋯O, C-H⋯Cl and C-H⋯π interactions and π⋯π stacking, which also contributes to structural stabilisation. The correlation between crystal structure and thermal stability of zinc complexes is observed. In all compounds the fragments of ligands donor-atom containing go in the last steps. Additionally, antimicrobial activities of compounds were carried out against certain Gram-positive and Gram-negative bacteria and counts of CFU (colony forming units) were also determined. The achieved results confirmed a significant antibacterial activity of some tested zinc complexes. On the basis of the Δ log CFU values the antibacterial activity of zinc complexes follows the order: 3 > 2 > 1. Influence a number of N-donor atoms in zinc environment on antibacterial activity is also observed.

Controlled release formulation of an anti-depression drug based on a L-phenylalanate-zinc layered hydroxide intercalation compound

NASA Astrophysics Data System (ADS)

Hashim, Norhayati; Sharif, Sharifah Norain Mohd; Isa, Illyas Md; Hamid, Shahidah Abdul; Hussein, Mohd Zobir; Bakar, Suriani Abu; Mamat, Mazidah

2017-06-01

The intercalation of L-phenylalanate (LP) into the interlayer gallery of zinc layered hydroxide (ZLH) has been successfully executed using a simple direct reaction method. The synthesised intercalation compound, zinc layered hydroxide-L-phenylalanate (ZLH-LP), was characterised using PXRD, FTIR, CHNS, ICP-OES, TGA/DTG, FESEM and TEM. The PXRD patterns of the intercalation compound demonstrate an intense and symmetrical peak, indicating a well-ordered crystalline layered structure. The appearance of an intercalation peak at a low angle of 2θ with a basal spacing of 16.3 Å, signifies the successful intercalation of the L-phenylalanate anion into the interlayer gallery of the host. The intercalation is also validated by FTIR spectroscopy and CHNS elemental analysis. Thermogravimetric analysis confirms that the ZLH-LP intercalation compound has higher thermal stability than the pristine L-phenylalanine. The observed percentage of L-phenylalanate accumulated release varies in each release media, with 84.5%, 79.8%, 63.8% and 61.8% release in phosphate buffer saline (PBS) solution at pH 4.8, deionised water, PBS solution at pH 7.4 and NaCl solution, respectively. The release behaviour of LP from its intercalation compounds in deionised water and PBS solution at pH 4.8 follows pseudo second order, whereas in NaCl solution and PBS solution at pH 7.4, it follows the parabolic diffusion model. This study shows that the synthesised ZLH-LP intercalation compound can be used for the formation of a new generation of materials for targeted drug release with controlled release properties.

Environmental assessment of cement/foundry sludge products.

PubMed

Ruiz, M C; Andrés, A; Irabien, A

2003-05-01

This work deals with the environmental assessment of products based on cement and a waste from a cast iron activity. The waste is a foundry sludge from wastewater treatment previously characterized. This industrial waste shows a high water content (62.4%) and a hazardous behavior due to its metallic content mainly Zn (16.5%), together with a low fraction of organic pollutants, mainly phenolic compounds. The feasibility of immobilizing both typs of contaminants was studied using Portland cement as binder at different cement/waste ratios. The parameters of environmental control were the ecotoxicity and mobilization of zinc and phenolic compounds, all determined on the basis of compliance leaching tests. The acid neutralization capacity of the cement/waste products was measured in order to obtain information on their buffering capacity. Experimental results from chemical analysis of leachates led to a non ecotoxic character of cement/waste products Although the metallic ions were mobilized within the cement mattices, the organic matter did not allow the formation of monolithic forms and an efficient immobilization of phenolic compounds. Concerning the acid neutralization capacity, this parameter was shown to depend mainly on the quantity of cement, although a decrease in alkalinity was observed when the amount of water in the cement/waste products increased.

In silico study toward the identification of new and safe potential inhibitors of photosynthetic electron transport.

PubMed

Ribeiro, Taisa Pereira Piacentini; Manarin, Flávia Giovana; Borges de Melo, Eduardo

2018-05-30

To address the rising global demand for food, it is necessary to search for new herbicides that can control resistant weeds. We performed a 2D-quantitative structure-activity relationship (QSAR) study to predict compounds with photosynthesis-inhibitory activity. A data set of 44 compounds (quinolines and naphthalenes), which are described as photosynthetic electron transport (PET) inhibitors, was used. The obtained model was approved in internal and external validation tests. 2D Similarity-based virtual screening was performed and 64 compounds were selected from the ZINC database. By using the VEGA QSAR software, 48 compounds were shown to have potential toxic effects (mutagenicity and carcinogenicity). Therefore, the model was also tested using a set of 16 molecules obtained by a similarity search of the ZINC database. Six compounds showed good predicted inhibition of PET. The obtained model shows potential utility in the design of new PET inhibitors, and the hit compounds found by virtual screening are novel bicyclic scaffolds of this class. Copyright © 2018 Elsevier Inc. All rights reserved.

Rational Design Synthesis and Evaluation of New Selective Inhibitors of Microbial Class II (Zinc Dependent) Fructose Bis-phosphate Aldolases

DOE Office of Scientific and Technical Information (OSTI.GOV)

R Daher; M Coincon; M Fonvielle

2011-12-31

We report the synthesis and biochemical evaluation of several selective inhibitors of class II (zinc dependent) fructose bis-phosphate aldolases (Fba). The products were designed as transition-state analogues of the catalyzed reaction, structurally related to the substrate fructose bis-phosphate (or sedoheptulose bis-phosphate) and based on an N-substituted hydroxamic acid, as a chelator of the zinc ion present in active site. The compounds synthesized were tested on class II Fbas from various pathogenic microorganisms and, by comparison, on a mammalian class I Fba. The best inhibitor shows Ki against class II Fbas from various pathogens in the nM range, with very highmore » selectivity (up to 105). Structural analyses of inhibitors in complex with aldolases rationalize and corroborate the enzymatic kinetics results. These inhibitors represent lead compounds for the preparation of new synthetic antibiotics, notably for tuberculosis prophylaxis.« less

Effect of short-term zinc supplementation on zinc and selenium tissue distribution and serum antioxidant enzymes.

PubMed

Skalny, Andrey A; Tinkov, Alexey A; Medvedeva, Yulia S; Alchinova, Irina B; Karganov, Mikhail Y; Skalny, Anatoly V; Nikonorov, Alexandr A

2015-01-01

A significant association between Zn and Se homeostasis exists. At the same time, data on the influence of zinc supplementation on selenium distribution in organs and tissues seem to be absent. Therefore, the primary objective of the current study is to investigate the influence of zinc asparaginate supplementation on zinc and selenium distribution and serum superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity in Wistar rats. 36 rats were used in the experiment. The duration of the experiment was 7 and 14 days in the first and second series, respectively. The rats in Group I were used as the control ones. Animals in Groups II and III daily obtained zinc asparaginate (ZnA) in the doses of 5 and 15 mg/kg weight, respectively. Zinc and selenium content in liver, kidneys, heart, muscle, serum and hair was assessed using inductively coupled plasma mass spectrometry. Serum SOD and GPx activity was analysed spectrophotometrically using Randox kits. Intragastric administration of zinc asparaginate significantly increased liver, kidney, and serum zinc content without affecting skeletal and cardiac muscle levels. Zinc supplementation also stimulated selenium retention in the rats' organs. Moreover, a significant positive correlation between zinc and selenium content was observed. Finally, zinc asparaginate treatment has been shown to modulate serum GPx but not SOD activity. The obtained data indicate that zinc-induced increase in GPx activity may be mediated through modulation of selenium status. However, future studies are required to estimate the exact mechanisms of zinc and selenium interplay.

Investigation of the surface composition of electrodeposited black chromium by X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Survilienė, S.; Češūnienė, A.; Jasulaitienė, V.; Jurevičiūtė, I.

2015-01-01

The paper reviews black chromium electrodeposited from a trivalent chromium bath containing ZnO as a second main component. The chemical compositions of the top layers of the black chromium coatings were studied by the X-ray photoelectron spectroscopy method. The surface of black chromium was found to be almost entirely covered with organic substances. To gain information on the state of each element in the deposit bulk, the layer-by-layer etching of the black chromium surface with argon gas was used. Analysis of XPS spectra has shown that the top layers of black chromium without zinc are composed of various Cr(III) components, organic substances and metallic Cr, whereas metallic Cr is almost absent in black chromium containing some amount of Zn(II) compounds. The ratios of metal/oxide phases were found to be 10/27 and 2/28 for black chromium without and with zinc, respectively. It has been determined that owing to the presence of ZnO in the Cr(III) bath, the percentage of metallic chromium is substantially reduced in black chromium which is quite important for good solar selective characteristics of the coating. The results confirm some of earlier observations and provide new information on the composition of the near-surface layers.

Strategies to prepare and use functionalized organometallic reagents.

PubMed

Klatt, Thomas; Markiewicz, John T; Sämann, Christoph; Knochel, Paul

2014-05-16

Polyfunctional zinc and magnesium organometallic reagents occupy a central position in organic synthesis. Most organic functional groups are tolerated by zinc organometallic reagents, and Csp(2)-centered magnesium organometallic reagents are compatible with important functional groups, such as the ester, aryl ketone, nitro, cyano, and amide functions. This excellent chemoselectivity gives zinc- and magnesium-organometallic reagents a central position in modern organic synthesis. Efficient and general preparations of these organometallic reagents, as well as their most practical and useful reactions, are presented in this Perspective. As starting materials, a broad range of organic halides (iodides, bromides, and also to some extent chlorides) can be used for the direct insertion of magnesium or zinc powder; the presence of LiCl very efficiently promotes such insertions. Alternatively, aromatic or heterocyclic bromides also undergo a smooth bromine-magnesium exchange when treated with i-PrMgCl·LiCl. Alternative precursors of zinc and magnesium reagents are polyfunctionalized aryl and heteroaryl molecules, which undergo directed metalations with sterically hindered TMP bases (TMP = 2,2,6,6-tetramethylpiperide) of magnesium and zinc. This powerful C-H functionalization method gives access to polyfunctional heterocyclic zinc and magnesium reagents, which undergo efficient reactions with numerous electrophiles. The compatibility of the strong TMP-bases with BF3·OEt2 (formation of frustrated Lewis pairs) dramatically increases the scope of these metalations, giving for example, a practical access to magnesiated pyridines and pyrazines, which can be used as convenient building blocks for the preparation of biologically active molecules.

Organic electrolyte-based rechargeable zinc-ion batteries using potassium nickel hexacyanoferrate as a cathode material

NASA Astrophysics Data System (ADS)

Chae, Munseok S.; Heo, Jongwook W.; Kwak, Hunho H.; Lee, Hochun; Hong, Seung-Tae

2017-01-01

This study demonstrates an organic electrolyte-based rechargeable zinc-ion battery (ZIB) using Prussian blue (PB) analogue potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086) as the cathode material. KNF-086 is prepared via electrochemical extraction of potassium ions from K1.51Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-151). The cell is composed of a KNF-086 cathode, a zinc metal anode, and a 0.5 M Zn(ClO4)2 acetonitrile electrolyte. This cell shows a reversible discharge capacity of 55.6 mAh g-1 at 0.2 C rate with the discharge voltage at 1.19 V (vs. Zn2+/Zn). As evidenced by Fourier electron density analysis with powder XRD data, the zinc-inserted phase is confirmed as Zn0.32K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (ZKNF-086), and the position of the zinc ion in ZKNF-086 is revealed as the center of the large interstitial cavities of the cubic PB. Compared to KNF-086, ZKNF-086 exhibits a decreased unit cell parameter (0.9%) and volume (2.8%) while the interatomic distance of d(Fe-C) increased (from 1.84 to 1.98 Å), and the oxidation state of iron decreases from 3 to 2.23. The organic electrolyte system provides higher zinc cycling efficiency (>99.9%) than the aqueous system (ca. 80%). This result demonstrates an organic electrolyte-based ZIB, and offers a crucial basis for understanding the electrochemical intercalation chemistry of zinc ions in organic electrolytes.

Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action

USGS Publications Warehouse

Wang, Ning; Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Alvarez, David; Hammer, Edward J.; Bauer, Candice R.; Augspurger, Tom; Raimondo, Sandy; Barnhart, M.Christopher

2017-01-01

Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r2 = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In contrast, the EC50s of fatmucket tested in the single-species study were in the high percentiles (>75th) of species sensitivity distributions for 6 of 7 organic chemicals, indicating mussels might be relatively insensitive to organic chemicals in acute exposures.

Two zinc-binding domains in the transporter AdcA from Streptococcus pyogenes facilitate high-affinity binding and fast transport of zinc.

PubMed

Cao, Kun; Li, Nan; Wang, Hongcui; Cao, Xin; He, Jiaojiao; Zhang, Bing; He, Qing-Yu; Zhang, Gong; Sun, Xuesong

2018-04-20

Zinc is an essential metal in bacteria. One important bacterial zinc transporter is AdcA, and most bacteria possess AdcA homologs that are single-domain small proteins due to better efficiency of protein biogenesis. However, a double-domain AdcA with two zinc-binding sites is significantly overrepresented in Streptococcus species, many of which are major human pathogens. Using molecular simulation and experimental validations of AdcA from Streptococcus pyogenes , we found here that the two AdcA domains sequentially stabilize the structure upon zinc binding, indicating an organization required for both increased zinc affinity and transfer speed. This structural organization appears to endow Streptococcus species with distinct advantages in zinc-depleted environments, which would not be achieved by each single AdcA domain alone. This enhanced zinc transport mechanism sheds light on the significance of the evolution of the AdcA domain fusion, provides new insights into double-domain transporter proteins with two binding sites for the same ion, and indicates a potential target of antimicrobial drugs against pathogenic Streptococcus species. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Different zinc sensitivity of Brassica organs is accompanied by distinct responses in protein nitration level and pattern.

PubMed

Feigl, Gábor; Kolbert, Zsuzsanna; Lehotai, Nóra; Molnár, Árpád; Ördög, Attila; Bordé, Ádám; Laskay, Gábor; Erdei, László

2016-03-01

Zinc is an essential microelement, but its excess exerts toxic effects in plants. Heavy metal stress can alter the metabolism of reactive oxygen (ROS) and nitrogen species (RNS) leading to oxidative and nitrosative damages; although the participation of these processes in Zn toxicity and tolerance is not yet known. Therefore this study aimed to evaluate the zinc tolerance of Brassica organs and the putative correspondence of it with protein nitration as a relevant marker for nitrosative stress. Both examined Brassica species (B. juncea and B. napus) proved to be moderate Zn accumulators; however B. napus accumulated more from this metal in its organs. The zinc-induced damages (growth diminution, altered morphology, necrosis, chlorosis, and the decrease of photosynthetic activity) were slighter in the shoot system of B. napus than in B. juncea. The relative zinc tolerance of B. napus shoot was accompanied by moderate changes of the nitration pattern. In contrast, the root system of B. napus suffered more severe damages (growth reduction, altered morphology, viability loss) and slighter increase in nitration level compared to B. juncea. Based on these, the organs of Brassica species reacted differentially to excess zinc, since in the shoot system modification of the nitration pattern occurred (with newly appeared nitrated protein bands), while in the roots, a general increment in the nitroproteome could be observed (the intensification of the same protein bands being present in the control samples). It can be assumed that the significant alteration of nitration pattern is coupled with enhanced zinc sensitivity of the Brassica shoot system and the general intensification of protein nitration in the roots is attached to relative zinc endurance. Copyright © 2015 Elsevier Inc. All rights reserved.

Optimization of salt fog conditions for organic zinc paints : final report.

DOT National Transportation Integrated Search

1981-10-01

Although Louisiana has been testing and using organic zinc coatings since 1963, premature failures have occurred on bridges within the state recently. These failures were not predicted by accelerated testing which included salt fog exposure. the resu...

Effect of boron and phosphate compounds on physical, mechanical, and fire properties of wood-polypropylene composites

Treesearch

Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Umit Buyuksari; Zeki Candan; Erkan Avci

2012-01-01

Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites incorporated with different contents of boron compounds; borax/boric acid and zinc borate, and phosphate compounds; mono and diammonium phosphates were investigated. The effect of the coupling agent content, maleic anhydride-grafted polypropylene, on the properties of...

Highly soluble 3,4-(dimethoxyphenylthio) substituted phthalocyanines: Synthesis, photophysical and photochemical studies

NASA Astrophysics Data System (ADS)

Öztürk, Cansu; Erdoğmuş, Ali; Durmuş, Mahmut; Uğur, Ahmet Lütfi; Kılıçarslan, Fatma Aytan; Erden, İbrahim

2012-02-01

The synthesis of a new 3,4-(dimethoxyphenylthio) substituted phthalonitrile ( 1) and its soluble metal free ( 2), zinc (II) ( 3), oxo-titanium (IV) ( 4) and nickel (II) ( 5) phthalocyanine derivatives are reported for the first time. The new compounds have been characterized by elemental analysis, FT-IR, 1H NMR, UV-Vis, fluorescence spectroscopies and mass spectra. General trends are described for fluorescence, photodegradation and singlet oxygen quantum yields and fluorescence lifetimes of oxo-titanium (IV) and zinc (II) phthalocyanine compounds in dimethylsulfoxide (DMSO). The effects of the metal ion on the photophysical and photochemical parameters for these phthalocyanines ( 3 and 4) are also reported.

Process for the manufacture of an attrition resistant sorbent used for gas desulfurization

DOEpatents

Venkataramani, Venkat S.; Ayala, Raul E.

2003-09-16

This process produces a sorbent for use in desulfurization of coal gas. A zinc titanate compound and a metal oxide are mixed by milling the compounds in an aqueous medium, the resulting mixture is dried and then calcined, crushed, sleved and formed into pellets for use in a moving-bed reactor. Metal oxides suitable for use as an additive in this process include: magnesium oxide, magnesium oxide plus molybdenum oxide, calcium oxide, yttrium oxide, hafnium oxide, zirconium oxide, cupric oxide, and tin oxide. The resulting sorbent has a percentage of the original zinc or titanium ions substituted for the oxide metal of the chosen additive.

Discovery of a new class of histone deacetylase inhibitors with a novel zinc binding group.

PubMed

Li, Youxuan; Woster, Patrick M

2015-04-01

Small molecules featuring a hydroxamic acid or a benzamide zinc binding group (ZBG) are the most thoroughly studied histone deacetylase (HDAC) inhibitors. However, concerns about the pharmacokinetic liabilities of the hydroxamic acid moiety and potential metabolic toxicity of the aniline portion of benzamide HDAC inhibitors have stimulated research efforts aimed at discovering alternative ZBGs. Here we report the 2-(oxazol-2-yl)phenol moiety as a novel ZBG that can be used to produce compounds that are potent HDAC inhibitors. A series of analogues with this novel ZBG have been synthesized, and these analogues exhibit selective inhibition against HDAC1 as well as the class IIb HDACs (HDAC6 and HDAC10). Compound 10 possesses an IC 50 value of 7.5 μM in the MV-4-11 leukemia cell line, and induces a comparable amount of acetylated histone 3 lysine 9 (H3K9) and p21Waf1/CIP1 as 0.5 μM of SAHA. Modeling of compound 10 in the active site of HDAC2 demonstrates that the 2-(oxazol-2-yl)phenol moiety has a zinc-binding pattern similar to benzamide HDAC inhibitors.

Skin bioavailability of dietary vitamin E, carotenoids, polyphenols, vitamin C, zinc and selenium.

PubMed

Richelle, Myriam; Sabatier, Magalie; Steiling, Heike; Williamson, Gary

2006-08-01

Dietary bioactive compounds (vitamin E, carotenoids, polyphenols, vitamin C, Se and Zn) have beneficial effects on skin health. The classical route of administration of active compounds is by topical application direct to the skin, and manufacturers have substantial experience of formulating ingredients in this field. However, the use of functional foods and oral supplements for improving skin condition is increasing. For oral consumption, some dietary components could have an indirect effect on the skin via, for example, secondary messengers. However, in the case of the dietary bioactive compounds considered here, we assume that they must pass down the gastrointestinal tract, cross the intestinal barrier, reach the blood circulation, and then be distributed to the different tissues of the body including the skin. The advantages of this route of administration are that the dietary bioactive compounds are metabolized and then presented to the entire tissue, potentially in an active form. Also, the blood continuously replenishes the skin with these bioactive compounds, which can then be distributed to all skin compartments (i.e. epidermis, dermis, subcutaneous fat and also to sebum). Where known, the distribution and mechanisms of transport of dietary bioactive compounds in skin are presented. Even for compounds that have been studied well in other organs, information on skin is relatively sparse. Gaps in knowledge are identified and suggestions made for future research.

Fatal cases of acute suicidal sodium and accidental zinc fluorosilicate poisoning. Review of acute intoxications due to fluoride compounds.

PubMed

Lech, Teresa

2011-03-20

Fluoride, of all inorganic substances, is among the least likely to be identified by a routine toxicological analysis. Acute poisonings with salts of hydrofluoric or fluorosilicic acid, however, although relatively uncommon, may occur. Some fluorosilicates, salts of fluorosilicic acid (e.g. Al, Zn, Pb, Mg) are used as stone consolidants, others (e.g. sodium fluorosilicate)--in the production of enamel and milk glass, or as insecticide. In this paper, two fatal cases of poisonings are presented: a suicide involving sodium fluorosilicate of a 39-year-old male who died in his flat, without hospitalization, and an accidental ingestion of zinc fluorosilicate solution (probably due to mistaking it for mineral water) by a 38-year-old male at his workplace (building), who died about 3h after ingestion of the liquid, in spite of intensive care at hospitals. Post-mortem samples were examined by the use of the spectrophotometric method with lanthanum nitrate and alizarin complexone for fluorine (after isolation of fluoride compounds by the microdiffusion method) and using a flame atomic absorption spectrometry method for zinc (after mineralization of biological material by sulfuric and nitric acids). In the first case, the results were: blood--130 μg F/ml, stomach--1150 μg F/g, small intestine content --19.6 μg F/g, kidney--56.0 μg F/g, and urine--1940 μg F/ml. In the second case, the contents of fluorine and zinc in blood and internal organs were the following: blood--6.03 μg F/ml, 23.8 μg Zn/ml; brain--1.39 μg F/g, 7.54 μg Zn/g; stomach--152 μg Zn/g; stomach content--293 μg F/g, 84.4 μg Zn/g; small intestine--37.5 μg Zn/g; small intestine content--63.4 μg F/g, 19.6 μg Zn/g; liver--9.49 μg F/g, 81.0 μg Zn/g; kidney--29.6 μg F/g, 39.2 μg Zn/g; and exceeded the normal levels of these elements in biological material many times. In addition, in stomach and liver large amounts of silica were detected. In the paper, a review of acute intoxications with various fluoride compounds (17 cases) is also presented. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Validation of artificial neural network models for predicting biochemical markers associated with male infertility.

PubMed

Vickram, A S; Kamini, A Rao; Das, Raja; Pathy, M Ramesh; Parameswari, R; Archana, K; Sridharan, T B

2016-08-01

Seminal fluid is the secretion from many glands comprised of several organic and inorganic compounds including free amino acids, proteins, fructose, glucosidase, zinc, and other scavenging elements like Mg(2+), Ca(2+), K(+), and Na(+). Therefore, in the view of development of novel approaches and proper diagnosis to male infertility, overall understanding of the biochemical and molecular composition and its role in regulation of sperm quality is highly desirable. Perhaps this can be achieved through artificial intelligence. This study was aimed to elucidate and predict various biochemical markers present in human seminal plasma with three different neural network models. A total of 177 semen samples were collected for this research (both fertile and infertile samples) and immediately processed to prepare a semen analysis report, based on the protocol of the World Health Organization (WHO [2010]). The semen samples were then categorized into oligoasthenospermia (n=35), asthenospermia (n=35), azoospermia (n=22), normospermia (n=34), oligospermia (n=34), and control (n=17). The major biochemical parameters like total protein content, fructose, glucosidase, and zinc content were elucidated by standard protocols. All the biochemical markers were predicted by using three different artificial neural network (ANN) models with semen parameters as inputs. Of the three models, the back propagation neural network model (BPNN) yielded the best results with mean absolute error 0.025, -0.080, 0.166, and -0.057 for protein, fructose, glucosidase, and zinc, respectively. This suggests that BPNN can be used to predict biochemical parameters for the proper diagnosis of male infertility in assisted reproductive technology (ART) centres. AAS: absorption spectroscopy; AI: artificial intelligence; ANN: artificial neural networks; ART: assisted reproductive technology; BPNN: back propagation neural network model; DT: decision tress; MLP: multilayer perceptron; PESA: percutaneous epididymal sperm spiration; RBFN: radical basis function network; SRNN: simple recurrent neural network; SVM: support vector machines; TSE: testicular sperm extraction; WHO: World Health Organization.

Cryomilled zinc sulfide: A prophylactic for Staphylococcus aureus-infected wounds

DOE PAGES

Tran, Phat L.; Li, Jianqiang; Lungaro, Lisa; ...

2018-04-23

Bacterial pathogens that colonize wounds form biofilms, which protect the bacteria from the effect of host immune response and antibiotics. This paper examined the effectiveness of newly synthesized zinc sulfide in inhibiting biofilm development by Staphylococcus aureus (S. aureus) strains. Zinc sulfide (ZnS) was anaerobically biosynthesized to produce CompA, which was further processed by cryomilling to maximize the antibacterial properties to produce CompB. The effect of the two compounds on the S. aureus strain AH133 was compared using zone of inhibition assay. The compounds were formulated in a polyethylene glycol cream. We compared the effect of the two compounds onmore » biofilm development by AH133 and two methicillin-resistant S. aureus clinical isolates using the in vitro model of wound infection. Zone of inhibition assay revealed that CompB is more effective than CompA. At 15 mg/application, the formulated cream of either compound inhibited biofilm development by AH133, which was confirmed using confocal laser scanning microscopy. At 20 mg/application, CompB inhibited biofilm development by the two methicillin-resistant S. aureus clinical isolates. To further validate the effectiveness of CompB, mice were treated using the murine model of wound infection. Finally, colony forming cell assay and in vivo live imaging results strongly suggested the inhibition of S. aureus growth.« less

Cryomilled zinc sulfide: A prophylactic for Staphylococcus aureus-infected wounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tran, Phat L.; Li, Jianqiang; Lungaro, Lisa

Bacterial pathogens that colonize wounds form biofilms, which protect the bacteria from the effect of host immune response and antibiotics. This paper examined the effectiveness of newly synthesized zinc sulfide in inhibiting biofilm development by Staphylococcus aureus (S. aureus) strains. Zinc sulfide (ZnS) was anaerobically biosynthesized to produce CompA, which was further processed by cryomilling to maximize the antibacterial properties to produce CompB. The effect of the two compounds on the S. aureus strain AH133 was compared using zone of inhibition assay. The compounds were formulated in a polyethylene glycol cream. We compared the effect of the two compounds onmore » biofilm development by AH133 and two methicillin-resistant S. aureus clinical isolates using the in vitro model of wound infection. Zone of inhibition assay revealed that CompB is more effective than CompA. At 15 mg/application, the formulated cream of either compound inhibited biofilm development by AH133, which was confirmed using confocal laser scanning microscopy. At 20 mg/application, CompB inhibited biofilm development by the two methicillin-resistant S. aureus clinical isolates. To further validate the effectiveness of CompB, mice were treated using the murine model of wound infection. Finally, colony forming cell assay and in vivo live imaging results strongly suggested the inhibition of S. aureus growth.« less

Targeting histone deacetylase inhibitors for anti-malarial therapy.

PubMed

Andrews, Katherine T; Tran, Thanh N; Wheatley, Nicole C; Fairlie, David P

2009-01-01

It is now clear that histone acetylation plays key roles in regulating gene transcription in both eukaryotes and prokaryotes, the acetylated form inducing gene expression while deacetylation silences genes. Recent studies have identified roles for histone acetyltransferases (HATs) and/or histone deacetylases (HDACs) in a number of parasites including Entamoeba histolytica, Toxoplasma gondii, Schistosoma mansoni, Cryptosporidium sp., Leishmania donovani, Neospora caninum, and Plasmodium falciparum. Here we survey fairly limited efforts to date in profiling antimalarial activities of HDAC inhibitors, showing that such compounds are potent inhibitors of the growth of P. falciparum in vitro and in vivo. Most of the compounds evaluated so far have borne a zinc-binding hydroxamate group that tends to be metabolized in vivo, and thus new zinc-binding groups need to be incorporated into second generation inhibitors in order to mask the catalytic zinc in the active site of HDACs. Also the development of compounds that are selective for parasitic HDACs over mammalian HDACs is still in relative infancy and it will take some time to derive antiparasitic HDAC inhibitor compounds with minimal toxicity for the host and acceptable pharmacokinetic and pharmacodynamic profiles for human treatment. Nevertheless, results to date suggest that HDAC inhibitor development represents a promising new approach to the potential treatment of parasitic infections, including those induced by malaria protozoa, and may offer new therapeutic targets within increasingly drug-resistant malarial parasites.

Effects of organic selenium and zinc on the aging process of laying hens

USDA-ARS?s Scientific Manuscript database

The objective of the study was to determine whether supplementing the diets of post-molted hens with organic selenium (Se) (Sel-Plex®) and/or organic Zinc (Zn) (Bio-Plex®) could improve laying hen performance. Prior to molting, 120-78 wk old laying hens were separated into four treatment groups of ...

On the origin of life in the zinc world: 1. Photosynthesizing, porous edifices built of hydrothermally precipitated zinc sulfide as cradles of life on Earth.

PubMed

Mulkidjanian, Armen Y

2009-08-24

The complexity of the problem of the origin of life has spawned a large number of possible evolutionary scenarios. Their number, however, can be dramatically reduced by the simultaneous consideration of various bioenergetic, physical, and geological constraints. This work puts forward an evolutionary scenario that satisfies the known constraints by proposing that life on Earth emerged, powered by UV-rich solar radiation, at photosynthetically active porous edifices made of precipitated zinc sulfide (ZnS) similar to those found around modern deep-sea hydrothermal vents. Under the high pressure of the primeval, carbon dioxide-dominated atmosphere ZnS could precipitate at the surface of the first continents, within reach of solar light. It is suggested that the ZnS surfaces (1) used the solar radiation to drive carbon dioxide reduction, yielding the building blocks for the first biopolymers, (2) served as templates for the synthesis of longer biopolymers from simpler building blocks, and (3) prevented the first biopolymers from photo-dissociation, by absorbing from them the excess radiation. In addition, the UV light may have favoured the selective enrichment of photostable, RNA-like polymers. Falsification tests of this hypothesis are described in the accompanying article (A.Y. Mulkidjanian, M.Y. Galperin, Biology Direct 2009, 4:27). The suggested "Zn world" scenario identifies the geological conditions under which photosynthesizing ZnS edifices of hydrothermal origin could emerge and persist on primordial Earth, includes a mechanism of the transient storage and utilization of solar light for the production of diverse organic compounds, and identifies the driving forces and selective factors that could have promoted the transition from the first simple, photostable polymers to more complex living organisms.

Evaluation of organic zinc coatings : final report.

DOT National Transportation Integrated Search

1969-08-01

The purpose was to find a more economical and time saving method for coating a steel bridge. This was accomplished by evaluating the cost and accelerated life of an organic zinc primer together with its appropriate topcoat versus the cost and life of...

Zinc and lead detoxifying abilities of humic substances relevant to environmental bacterial species.

PubMed

Perelomov, L V; Sarkar, Binoy; Sizova, O I; Chilachava, K B; Shvikin, A Y; Perelomova, I V; Atroshchenko, Y M

2018-04-30

The effect of humic substances (HS) and their different fractions (humic acids (HA) and hymatomelanic acids (HMA)) on the toxicity of zinc and lead to different strains of bacteria was studied. All tested bacteria demonstrated a lower resistance to zinc than lead showing minimum inhibitory concentrations of 0.1 - 0.3mM and 0.3-0.5mM, respectively. The highest resistance to lead was characteristic of Pseudomonas chlororaphis PCL1391 and Rhodococcus RS67, while Pseudomonas chlororaphis PCL1391 showed the greatest resistance to zinc. The combined fractions of HS and HA alone reduced zinc toxicity at all added concentrations of the organic substances (50 - 200mgL -1 ) to all microorganisms, while hymatomelanic acids reduced zinc toxicity to Pseudomonas chlororaphis PCL1391 at 200mgL -1 organic concentration only. The HS fractions imparted similar effects on lead toxicity also. This study demonstrated that heavy metal toxicity to bacteria could be reduced through complexation with HS and their fractions. This was particularly true when the metal-organic complexes held a high stability, and low solubility and bioavailability. Copyright © 2018 Elsevier Inc. All rights reserved.

A zinc, copper and citric acid biocomplex shows promise for control of Xylella fastidiosa subsp. pauca in olive trees in Apulia region (southern Italy)

USDA-ARS?s Scientific Manuscript database

The bacterium Xylella fastidiosa subsp. pauca is associated with the “olive quick decline syndrome” in the Apulia region of southern Italy. To investigate control of this phytopathogen, a compound containing zinc and copper complexed with citric-acid hydracids (Dentamet®) was evaluated for in vitro ...

Virtual Lead Identification of Farnesyltransferase Inhibitors Based on Ligand and Structure-Based Pharmacophore Techniques

PubMed Central

Al-Balas, Qosay A.; Amawi, Haneen A.; Hassan, Mohammad A.; Qandil, Amjad M.; Almaaytah, Ammar M.; Mhaidat, Nizar M.

2013-01-01

Farnesyltransferase enzyme (FTase) is considered an essential enzyme in the Ras signaling pathway associated with cancer. Thus, designing inhibitors for this enzyme might lead to the discovery of compounds with effective anticancer activity. In an attempt to obtain effective FTase inhibitors, pharmacophore hypotheses were generated using structure-based and ligand-based approaches built in Discovery Studio v3.1. Knowing the presence of the zinc feature is essential for inhibitor’s binding to the active site of FTase enzyme; further customization was applied to include this feature in the generated pharmacophore hypotheses. These pharmacophore hypotheses were thoroughly validated using various procedures such as ROC analysis and ligand pharmacophore mapping. The validated pharmacophore hypotheses were used to screen 3D databases to identify possible hits. Those which were both high ranked and showed sufficient ability to bind the zinc feature in active site, were further refined by applying drug-like criteria such as Lipiniski’s “rule of five” and ADMET filters. Finally, the two candidate compounds (ZINC39323901 and ZINC01034774) were allowed to dock using CDOCKER and GOLD in the active site of FTase enzyme to optimize hit selection. PMID:24276257

Virtual lead identification of farnesyltransferase inhibitors based on ligand and structure-based pharmacophore techniques.

PubMed

Al-Balas, Qosay A; Amawi, Haneen A; Hassan, Mohammad A; Qandil, Amjad M; Almaaytah, Ammar M; Mhaidat, Nizar M

2013-05-27

Farnesyltransferase enzyme (FTase) is considered an essential enzyme in the Ras signaling pathway associated with cancer. Thus, designing inhibitors for this enzyme might lead to the discovery of compounds with effective anticancer activity. In an attempt to obtain effective FTase inhibitors, pharmacophore hypotheses were generated using structure-based and ligand-based approaches built in Discovery Studio v3.1. Knowing the presence of the zinc feature is essential for inhibitor's binding to the active site of FTase enzyme; further customization was applied to include this feature in the generated pharmacophore hypotheses. These pharmacophore hypotheses were thoroughly validated using various procedures such as ROC analysis and ligand pharmacophore mapping. The validated pharmacophore hypotheses were used to screen 3D databases to identify possible hits. Those which were both high ranked and showed sufficient ability to bind the zinc feature in active site, were further refined by applying drug-like criteria such as Lipiniski's "rule of five" and ADMET filters. Finally, the two candidate compounds (ZINC39323901 and ZINC01034774) were allowed to dock using CDOCKER and GOLD in the active site of FTase enzyme to optimize hit selection.

Rainfall, streamflow, and water-quality data for five small watersheds, Nashville, Tennessee, 1990-92

USGS Publications Warehouse

Outlaw, George S.; Hoos, Anne B.; Pankey, John T.

1994-01-01

Rainfall, streamflow, and water-quality data were collected furing storm conditions at five urban watersheds in Nashville, Tennessee. These data can be used to build a database for developing predictive models of the relations between storm- water quality and land use, storm characteristics, and seasonal variations. The primary land and mix of land uses was different for each watershed. Stormwater samples were collected during three storms at each watershed and analyzed for selected volatile, acidic and base/neutral organic compounds; organic pesticides; trace metals; conventional pollutants; and several physical properties. Storm loads were computed for all constituents and properties with event mean concentration above the minimum reporting level. None of the samples con- tained acidic organic compounds at concentrations above the minimum reporting levels. Several constituents in each of the other categories, however, were present at concentrations above the minimum reporting level. For 21 of these constituents, water-quality criteria have been pro- mulgated by the State of Tennessee. For only 8 of the 21 did the value exceed the most restrictive of the criteria: pyrene, dieldrin, and mercury concen- trations and counts of fecal coliform exceeded the criteria for recreational use, copper and zinc concentrations and pH value exceeded the criteria for fish and aquatic life, and lead concentrations exceeded the criteria for domestic supply.

The water soluble peripherally tetra-substituted zinc(ii), manganese(iii) and copper(ii) phthalocyanines as new potential anticancer agents.

PubMed

Barut, Burak; Sofuoğlu, Ayşenur; Biyiklioglu, Zekeriya; Özel, Arzu

2016-09-28

In this study, [2-(2-morpholin-4-ylethoxy)ethoxy] group substituted zinc(ii), manganese(iii) and copper(ii) phthalocyanines 2-4 and their water soluble derivatives 2a, 3a and 4a were synthesized and the interactions of compounds 2a, 3a and 4a with CT-DNA and supercoiled pBR322 plasmid DNA were investigated. The results of binding experiments showed that these compounds were able to interact with CT-DNA via intercalative mode with a strong binding affinity in the order 3a > 2a > 4a. DNA-photocleavage activities of compounds 2a, 3a and 4a were determined. These compounds cleaved supercoiled pBR322 plasmid DNA efficiently under irradiation at 650 nm for 2a and 4a, and at 750 nm for 3a. These compounds displayed remarkable inhibitory activities against topoisomerase I enzyme in a dose-dependent manner. All of these results suggest that these phthalocyanines might be suitable anticancer agents due to their strong binding affinities, significant cleavage activities and effective topoisomerase I inhibition.

Gas-phase study of new organozinc reagents by IRMPD-spectroscopy, computational modelling and tandem-MS.

PubMed

Massah, Ahmad R; Dreiocker, Frank; Jackson, Richard F W; Pickup, Barry T; Oomens, Jos; Meijer, Anthony J H M; Schäfer, Mathias

2011-08-07

An extensive set of organozinc iodides, useful for Negishi-type cross-coupling reactions, are investigated as respective cations after formal loss of iodide in the gas phase. Firstly, two new alkylzinc compounds derived from Tyrosine (Tyr) and Tryptophan (Trp) are closely examined. Secondly, the influence of specific protecting groups on the subtle balance between intra- and intermolecular coordination of zinc in these reagents is probed through trifluoroacetyl (TFA)-derivatized alkylzinc compounds. Finally, the influence of the strongly coordinating bidentate ligand N,N,N',N'-tetramethylethylenediamine (TMEDA) on the structure of alkylzinc cations is further explored in order to better understand the stability of the respective complexes towards water. A combination of electrospray (ESI)-MS/MS, accurate ion mass measurements, infrared multiple-photon dissociation (IRMPD) spectroscopy and computational modelling allowed the full characterisation of all dimethylformamide (DMF)-solvated and TMEDA-coordinated alkylzinc cations in the gas phase. The calculations indicate that the zinc cation in gas-phase alkylzinc-DMF or TMEDA-complex ions preferentially adopts a tetrahedral coordination sphere with four ligands. Additionally, conformers with only three binding partners bound to zinc but with effectively combined hydrogen-bond interactions are also found. Collision induced dissociation (CID) patterns demonstrate that the zinc-DMF interaction in tetrahedral four-coordinate mono-DMF-zinc complex ions as well as the interaction between TMEDA and zinc in the corresponding complex ions is even stronger than typical covalent bonds. In most cases, all major features of the IRMPD spectra are consistent with only a single major isomer, allowing secured identification and assignment. This journal is © the Owner Societies 2011

Volatile organometallic complexes suitable for use in chemical vapor depositions on metal oxide films

DOEpatents

Giolando, Dean M.

2003-09-30

Novel ligated compounds of tin, titanium, and zinc are useful as metal oxide CVD precursor compounds without the detriments of extreme reactivity yet maintaining the ability to produce high quality metal oxide coating by contact with heated substrates.

Catalysts for coal liquefaction processes

DOEpatents

Garg, Diwakar

1986-01-01

Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

Catalysts for coal liquefaction processes

DOEpatents

Garg, D.

1986-10-14

Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

Synthesis and crystal structures of coordination compounds of pyridoxine with zinc and cadmium sulfates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furmanova, N. G., E-mail: furm@ns.crys.ras.ru; Berdalieva, Zh. I., E-mail: kakin@inbox.ru; Chernaya, T. S.

2009-03-15

The pyridoxine complexes with zinc and cadmium sulfates are synthesized. The IR absorption spectra and thermal behavior of the synthesized compounds are described. Crystals of the [M(C{sub 8}H{sub 11}O{sub 3}N){sub 2}(H{sub 2}O){sub 2}]SO{sub 4} . 3H{sub 2}O (M = Zn, Cd) compounds are investigated using X-ray diffraction. In the structures of both compounds, the M atoms are coordinated by the oxygen atoms of the deprotonated OH group and the CH{sub 2}OH group retaining its own hydrogen atom, as well as by two H{sub 2}O molecules, and have an octahedral coordination. The nitrogen atom of the heterocycle is protonated, so thatmore » the heterocycle acquires a pyridinium character. The cationic complexes form layers separated by the anions and crystallization water molecules located in between. The structural units of the crystals are joined together by a complex system of hydrogen bonds.« less

Identification of novel peroxisome proliferator-activated receptor-gamma (PPARγ) agonists using molecular modeling method

NASA Astrophysics Data System (ADS)

Gee, Veronica M. W.; Wong, Fiona S. L.; Ramachandran, Lalitha; Sethi, Gautam; Kumar, Alan Prem; Yap, Chun Wei

2014-11-01

Peroxisome proliferator-activated receptor-gamma (PPARγ) plays a critical role in lipid and glucose homeostasis. It is the target of many drug discovery studies, because of its role in various disease states including diabetes and cancer. Thiazolidinediones, a synthetic class of agents that work by activation of PPARγ, have been used extensively as insulin-sensitizers for the management of type 2 diabetes. In this study, a combination of QSAR and docking methods were utilised to perform virtual screening of more than 25 million compounds in the ZINC library. The QSAR model was developed using 1,517 compounds and it identified 42,378 potential PPARγ agonists from the ZINC library, and 10,000 of these were selected for docking with PPARγ based on their diversity. Several steps were used to refine the docking results, and finally 30 potentially highly active ligands were identified. Four compounds were subsequently tested for their in vitro activity, and one compound was found to have a K i values of <5 μM.

New Approach for Fractioning Metal Compounds Studies in Soils

NASA Astrophysics Data System (ADS)

Minkina, Tatiana; Motuzova, Galina; Mandzhieva, Saglara; Bauer, Tatiana; Burachevskaya, Marina; Sushkova, Svetlana; Nevidomskaya, Dina; Kalinitchenko, Valeriy

2016-04-01

A combined approach for fractioning metal compounds in soils on the basis of sequential (Tessier, 1979) and parallel extractions (1 N NH4Ac, pH 8; 1% EDTA in NH4Ac; and 1N HCl) is proposed. Metal compounds in sequential and parallel extracts are grouped according to the strength of their bonds with soil components. A given group includes metal compounds with similar strengths of bonds and, hence, with similar migration capacities. The groups of firmly and loosely bound metal compounds can be distinguished. This approach has been used to assess the group composition of Zn, Cu, and Pb compounds in an ordinary chernozem and its changes upon the soil contamination with metals. Contamination of an ordinary chernozem from Rostov oblast with heavy metals caused a disturbance of the natural ratios between the metal compounds. In the natural soil, firmly bound metals predominate (88-95%of the total content), which is mainly caused by the fixation of metals in lattices of silicate minerals (56-83%of the total content). The mobility of the metals in the natural soil is low (5-12%) and is mainly related to metal compounds loosely bound with the soil carbonates. Upon the soil contamination with metals (application rates of 100-300 mg/kg), the content of all the metal compounds increases, but the ratio between them shifts towards a higher portion of the potentially mobile metal compounds (up to 30-40% of the bulk contents of the metals). Organic substances and non-silicate Fe, Al, and Mn minerals become the main carriers of the firmly and loosely bound metals. The strengths of their bonds with Cu, Pb, and Zn differ. Lead in the studied chernozems is mainly fixed in a loosely bound form with organic matter, whereas copper and zinc are fixed both by the organic matter and by the non-silicate Fe, Al, and Mn compounds. Firm fixation of the applied Cu and Pb is mainly ensured by the soil organic matter and non-silicate minerals, whereas firm fixation of Zn is mainly due to non-silicate minerals. The amount of the applied metals fixed in the lattices of the silicate minerals is insignificant. Hence, all the soil components participate in the loose and firm fixation of the metals. The leading role in mobilization-immobilization of natural metal compounds in the ordinary chernozem belongs to carbonates and silicate minerals. For exogenic metal compounds, this role belongs to the soil organic matter and Fe-Mn oxides and hydroxides. The obtained data are important for ecology because they enable us to predict the transformation of soil components responsible for metal fixation and the possibility of their secondary mobilization. The danger of metal mobilization is more probable for metal compounds with organic substances that are particularly active in the loose binding of the introduced metals. This work was supported by the Ministry of Science of the Russian Federation, project no. 5.885.2014/K, the Russian Foundation for Basic Research, projects no. № 14-05-00586_a.

Effect of Boron and Phosphate compounds on Thermal and Fire Properties of wood/HDPE composites

Treesearch

Turgay Akbulut; Nadir Ayrilmis; Turker Dundar; Ali Durmus; Robert H. White; Murat Teker

2011-01-01

Melting and non-isothermal crystallization behaviors, oxidative induction time, and fire performance of the injection-molded wood flour-high density polyethylene (HDPE) composites (WPCs) incorporated with different levels (4, 8, or 12 wt %) of boron compounds [borax/boric acid (BX/BA) (0.5:0.5 wt %), zinc borate (ZB)] and phosphorus compounds [mono- and di-ammonium...

Polyorganometallosiloxane-2- or -4-pyridine coatings

DOEpatents

Sugama, Toshifumi

1997-01-01

A new family of polyorganometallosiloxane-2- or -4-pyridine compounds are provided for corrosion resistant coatings on light metals such as aluminum, magnesium, zinc, steel and their allows. The novel compounds contain backbones modified by metal alkoxides, metallocenes and metallophthalocyanates where the metal is Zr, Ti, Mo, V, Hf, Nb, Si, B and combinations thereof. Methods of making the new compounds are also provided.

Zinc-rich coatings: A market survey

NASA Technical Reports Server (NTRS)

Lizak, R.

1975-01-01

Zinc-rich coatings with both organic and inorganic binders were considered for coastal bridges which require more corrosion protection than inland bridges because of exposure to salt spray and fog. Inorganics give longer protection and may be applied without a finish coat; those currently available are harder to apply than organics. The NASA potassium silicate/zinc - dust coating appears to provide longer protection, resist thermal shock, and overcome the application problem. Panels coated with the formulation withstood 5308 hours in a salt spray chamber with no rusting or blistering.

Secondary battery containing zinc electrode with modified separator and method

DOEpatents

Poa, David S.; Yao, Neng-Ping

1985-01-01

A battery containing a zinc electrode with a porous separator between the anode and cathode. The separator is a microporous substrate carrying therewith an organic solvent of benzene, toluene or xylene with a tertiary organic amine therein, wherein the tertiary amine has three carbon chains each containing from six to eight carbon atoms. The separator reduces the rate of zinc dentrite growth in the separator during battery operation prolonging battery life by preventing short circuits. A method of making the separator is also disclosed.

Secondary battery containing zinc electrode with modified separator and method

DOEpatents

Poa, D.S.

1984-02-16

A battery containing a zinc electrode with a porous separator between the anode and cathode. The separator is a microporous substrate carrying therewith an organic solvent of benzene, toluene or xylene with a tertiary organic amine therein, wherein the tertiary amine has three carbon chains each containing from six to eight carbon atoms. The separator reduces the rate of zinc dentrite growth in the separator during battery operation prolonging battery life by preventing short circuits. A method of making the separator is also disclosed.

Organic acid compounds in root exudation of Moso Bamboo (Phyllostachys pubescens) and its bioactivity as affected by heavy metals.

PubMed

Chen, Junren; Shafi, Mohammad; Wang, Ying; Wu, Jiasen; Ye, Zhengqian; Liu, Chen; Zhong, Bin; Guo, Hua; He, Lizhi; Liu, Dan

2016-10-01

Moso bamboo (Phyllostachys pubescens) has great potential as phytoremediation material in soil contaminated by heavy metals. A hydroponics experiment was conducted to determine organic acid compounds of root exudates of lead- (Pb), zinc- (Zn), copper- (Cu), and cadmium (Cd)-tolerant of Moso bamboo. Plants were grown in nutrients solution which included Pb, Zn, Cu, and Cd applied as Pb(NO 3 ) 2 (200 μM), ZnSO 4 ·7H 2 O (100 μM), CuSO 4 ·5H 2 O (25 μM), and CdCl 2 (10 μM), respectively. Oxalic acid and malic acid were detected in all treatments. Lactic acid was observed in Cu, Cd, and control treatments. The oxalic was the main organic acid exudated by Moso bamboo. In the sand culture experiment, the Moso bamboo significantly activated carbonate heavy metals under activation of roots. The concentration of water-soluble metals (except Pb) in sand were significantly increased as compared with control. Organic acids (1 mM mixed) were used due to its effect on the soil adsorption of heavy metals. After adding mixed organic acids, the Cu and Zn sorption capacity in soils was decreased markedly compared with enhanced Pb and Cd sorption capacity in soils. The sorption was analyzed using Langmuir and Freundlich equations with R 2 values that ranged from 0.956 to 0.999 and 0.919 to 0.997, respectively.

A new zinc coordination polymer in (10, 3)-d framework with unusual redox property

NASA Astrophysics Data System (ADS)

Huo, Jianqiang; Yan, Shuai; Arulsamy, Navamoney

2017-11-01

A new coordination polymer, [Zn(H1dimb)(Cl)]n (1) (H1dimb = 2,5-di (1H-imidazol-1-yl)benzoate), is obtained by hydrothermal synthesis and characterized by single crystal X-ray diffraction data and elemental analysis. Compound 1 crystallizes in the orthorhombic space group Pccn, and its structure exhibits a rarely observed ultimate racemic 3D network with 2-fold interpenetrating (10, 3)-d (or utp) topology due to the presence of alternating arrays of left- and right-handed helices. Thermo-gravimetric analysis (TGA) data for 1 reveals that the metal-organic framework (MOF) is thermally stable up to 350 °C under a N2 atmosphere. Compound 1 also possesses interesting photoluminescent properties as expected for Zn2+ complexes of aromatic ligands. Photoemission spectra measured in the solid state reveal a very strong emission band centered at 417 nm. Cyclic voltammetric data reveal that the compound exhibits quasi reversible two-electron redox process in acidic aqueous solution and the surprising electrochemical behavior is attributed to the Zn/Zn2+ process.

Trace elements and organic compounds in sediment and fish tissue from the Great Salt Lake basins, Utah, Idaho, and Wyoming, 1998-99

USGS Publications Warehouse

Waddell, Kidd M.; Giddings, Elise M.

2004-01-01

A study to determine the occurrence and distribution of trace elements, organochlorine pesticides, polychlorinated biphenyls (PCBs), and semivolatile organic compounds in sediment and in fish tissue was conducted in the Great Salt Lake Basins study unit of the National Water-Quality Assessment (NAWQA) program during 1998-99. Streambed-sediment and fish-tissue samples were collected concurrently at 11 sites and analyzed for trace-element concentration. An additional four sites were sampled for streambed sediment only and one site for fish tissue only. Organic compounds were analyzed from streambed-sediment and fish-tissue samples at 15 sites concurrently.Bed-sediment cores from lakes, reservoirs, and Farmington Bay collected by the NAWQA program in 1998 and by other researchers in 1982 were used to examine historical trends in trace-element concentration and to determine anthropogenic sources of contaminants. Cores collected in 1982 from Mirror Lake, a high-mountain reference location, showed an enrichment of arsenic, cadmium, copper, lead, tin, and zinc in the surface sediments relative to the deeper sediments, indicating that enrichment likely began after about 1900. This enrichment was attributed to atmospheric deposition during the period of metal-ore mining and smelting. A core from Echo Reservoir, in the Weber River Basin, however, showed a different pattern of trace-element concentration that was attributed to a local source. This site is located downstream from the Park City mining district, which is the most likely historical source of trace elements. Cores collected in 1998 from Farmington Bay show that the concentration of lead began to increase after 1842 and peaked during the mid-1980s and has been in decline since. Recent sediments deposited during 1996-98 indicate a 41- to 62-percent reduction since the peak in the mid-1980s.The concentration of trace elements in streambed sediment was greatest at sites that have been affected by historic mining, including sites on Little Cottonwood Creek in the Jordan River basin, Silver Creek in the Weber River basin, and the Weber River below the confluence with Silver Creek. There was significant correlation of lead concentrations in streambed sediment and fish tissue, but other trace elements did not correlate well. Streambed sediment and fish tissue collected from sites in the Bear River basin, which is predominantly rangeland and agriculture, generally had low concentrations of most elements.Sediment-quality guidelines were used to assess the relative toxicity of streambed-sediment sites to aquatic communities. Sites affected by mining exceeded the Probable Effect Concentration (PEC), the concentration at which it is likely there will be a negative effect on the aquatic community, for arsenic, cadmium, copper, lead, silver, mercury, and zinc. Sites that were not affected by mining did not exceed these criteria. Concentrations of trace elements in samples collected from the Great Salt Lake Basins study unit (GRSL) are high compared to those of samples collected nationally with the NAWQA program. Nine of 15 streambed-sediment samples and 11 of 14 fish-tissue samples had concentrations of at least one trace element greater than the concentration of 90 percent of the samples collected nationally during 1993-2000.Organic compounds that were examined in streambed sediment and fish-tissue samples also were examined in bed-sediment cores. A bed-sediment core from Farmington Bay of Great Salt Lake showed an increase in total polycyclic aromatic hydrocarbon (PAH) concentrations coincident with the increase in population in Salt Lake Valley, which drains into this bay. Analysis of streambed-sediment samples showed that the highest concentrations of PAHs were detected at urban sites, including two sites in the lower Jordan River (the Jordan River flows into Farmington Bay), the Weber River at Ogden Bay, and the Provo River near Provo. Other organic compounds detected in streambed sediment in the lower Jordan River were PCBs, DDT compounds, and chlordane compounds.Organic compounds were detected more frequently in fish tissue than in streambed sediment. Chlordane compounds and PCBs were detected more frequently at urban sites. DDT compounds were detected at 13 of 15 sites including urban and agricultural sites. Concentrations of total DDT in fish tissue exceeded the guideline for protection of fish-eating wildlife at two urban sites. The concentration of organic compounds in the GRSL study unit is low compared with that of samples collected nationally.

Hydrothermal syntheses, crystal structures and luminescence properties of zinc(II) and cadmium(II) coordination polymers based on bifunctional 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Na; Guo, Hui-Lin; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN

2013-02-15

Five new coordination polymers, [Zn{sub 2}(ctpy){sub 2}Cl{sub 2}]{sub n} (1), [Zn{sub 2}(ctpy){sub 2}(ox)(H{sub 2}O){sub 2}]{sub n} (2), [Zn{sub 2}(ctpy)(3-btc)(H{sub 2}O)]{sub n}{center_dot}0.5nH{sub 2}O (3), [Cd(ctpy){sub 2}(H{sub 2}O)]{sub n} (4), [Cd{sub 4}(ctpy){sub 2}(2-btc){sub 2}(H{sub 2}O){sub 2}]{sub n}{center_dot}2nH{sub 2}O (5), (Hctpy=3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid, H{sub 2}ox=oxalic acid, H{sub 3}(3-btc)=1,3,5-benzenetricarboxylic acid, H{sub 3}(2-btc)=1,2,4-benzenetricarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Compounds 1-2 are a one-dimensional chain with weak interactions to form 3D supramolecular structures. Compound 3 is a 4-nodal 3D topology framework comprised of binuclear zincmore » units and (ctpy){sup -} anions. Compound 4 shows two dimensional net. Compound 5 is a (4,5,6)-connected framework with {l_brace}4{sup 4}{center_dot}6{sup 2}{r_brace}{l_brace}4{sup 6}{center_dot}6{sup 4}{r_brace}{sub 2}{l_brace}4{sup 9}{center_dot}6{sup 6}{r_brace} topology. In addition, the thermal stabilities and photoluminescence properties of 1-5 were also studied in the solid state. - Graphical abstract: Five new Zn/Cd compounds with 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid were prepared. The photoluminescence and thermal stabilities properties of 1-5 were investigated in the solid state. Highlights: Black-Right-Pointing-Pointer Five new zinc/cadmium metal-organic frameworks have been hydrothermal synthesized. Black-Right-Pointing-Pointer The structural variation is attributed to the diverse metal ions and auxiliary ligand. Black-Right-Pointing-Pointer Compounds 1-5 exhibit 1D ring chain, 2D layer and 3D open-framework, respectively. Black-Right-Pointing-Pointer These compounds exhibit strong solid state luminescence emission at room temperature.« less

Zinc Chromate Induces Chromosome Instability and DNA Double Strand Breaks in Human Lung Cells

PubMed Central

Xie, Hong; Holmes, Amie L.; Young, Jamie L.; Qin, Qin; Joyce, Kellie; Pelsue, Stephen C.; Peng, Cheng; Wise, Sandra S.; Jeevarajan, Antony S.; Wallace, William T.; Hammond, Dianne; Wise, John Pierce

2014-01-01

Hexavalent chromium Cr(VI) is a respiratory toxicant and carcinogen, with solubility playing an important role in its carcinogenic potential. Zinc chromate, a water insoluble or ‘particulate’ Cr(VI) compound, has been shown to be carcinogenic in epidemiology studies and to induce tumors in experimental animals, but its genotoxicity is poorly understood. Our study shows that zinc chromate induced concentration-dependent increases in cytotoxicity, chromosome damage and DNA double strand breaks in human lung cells. In response to zinc chromate-induced breaks, MRE11 expression was increased and ATM and ATR were phosphorylated, indicating that the DNA double strand break repair system was initiated in the cells. In addition, our data show that zinc chromate-induced double strand breaks were only observed in the G2/M phase population, with no significant amount of double strand breaks observed in G1 and S phase cells. These data will aid in understanding the mechanisms of zinc chromate toxicity and carcinogenesis. PMID:19027772

Synthesis of hydrophobic zinc borate nanoflakes and its effect on flame retardant properties of polyethylene

NASA Astrophysics Data System (ADS)

Li, Shengli; Long, Beihong; Wang, Zichen; Tian, Yumei; Zheng, Yunhui; Zhang, Qian

2010-04-01

Zinc borate (2ZnO·3B 2O 3·3.5H 2O) has relatively high dehydration on-set temperature which property permits processing in a wide range of polymer system. But zinc borate particles are hardly dispersed in a polymer matrix so that they prevent their using in industry. To address this problem, we synthesized hydrophobic zinc borate (2ZnO·3B 2O 3·3.5H 2O) nanoflakes by employing solid-liquid reaction of zinc oxide (ZnO) and boric acid (H 3BO 3) in the presence of oleic acid. This method does not bring pollution. By conducting morphological and microscopic analyses, we found that this compound displayed nanoflake morphology with particle size of around 100-200 nm, thickness less than 100 nm and there were uniform mesopores with the diameter about 10 nm within the particles. Furthermore, our products had an effect on flame retardant of polyethylene, especially when the zinc borate was modified by oleic acid.

Iron and zinc bioaccessibility of fermented maize, sorghum and millets from five locations in Zimbabwe.

PubMed

Gabaza, Molly; Shumoy, Habtu; Muchuweti, Maud; Vandamme, Peter; Raes, Katleen

2018-01-01

The present study is an evaluation of iron and zinc bioaccessibility of fermented maize, sorghum, pearl millet and finger millet from five different locations in Zimbabwe. Iron and zinc contents ranged between 3.22 and 49.7 and 1.25-4.39mg/100gdm, respectively. Fermentation caused a reduction of between 20 and 88% of phytic acid (PA) while a general increase in soluble phenolic compounds (PC) and a decrease of the bound (PC) was observed. Bioaccessibility of iron and zinc ranged between 2.77 and 26.1% and 0.45-12.8%, respectively. The contribution of the fermented cereals towards iron and zinc absolute requirements ranged between 25 and 411% and 0.5-23% with higher contribution of iron coming from cereals that were contaminated with extrinsic iron. Populations subsisting on cereals could be more at risk of zinc rather than iron deficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

The membrane-stabilizing action of zinc carnosine (Z-103) in stress-induced gastric ulceration in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, C.H.; Luk, C.T.; Ogle, C.W.

1991-01-01

Zinc compounds have been shown to antagonize various types of gastric ulceration in rats. Zinc carnosine (Z-103), a newly developed agent was, therefore, examined for its antiulcer effect in stress-induced ulceration and also its membrane stabilizing action in rat stomachs. Cold-restraint stress induced severe hemorrhagic lesions together with increased mast cell degranulation and {beta}-glucuronidase release in the gastric glandular mucosa. A-103 pretreatment with a single oral dose reversed these actions in a dose-dependent manner. When the compound was incubated in concentrations of 10{sup {minus}7}, 10{sup {minus}6}, 10{sup {minus}5} or 10{sup {minus}4} M, with isolated hepatic lysosomes, it significantly reduced themore » spontaneous release of {beta}-glucuronidase in the medium. The present study not only demonstrates the antiulcer effect of Z-103 but also indicates that the protective action is likely to be mediated by its membrane-stabilizing action on mast cells and lysosomes in the gastric glandular mucosa.« less

Novel hits for acetylcholinesterase inhibition derived by docking-based screening on ZINC database.

PubMed

Doytchinova, Irini; Atanasova, Mariyana; Valkova, Iva; Stavrakov, Georgi; Philipova, Irena; Zhivkova, Zvetanka; Zheleva-Dimitrova, Dimitrina; Konstantinov, Spiro; Dimitrov, Ivan

2018-12-01

The inhibition of the enzyme acetylcholinesterase (AChE) increases the levels of the neurotransmitter acetylcholine and symptomatically improves the affected cognitive function. In the present study, we searched for novel AChE inhibitors by docking-based virtual screening of the standard lead-like set of ZINC database containing more than 6 million small molecules using GOLD software. The top 10 best-scored hits were tested in vitro for AChE affinity, neurotoxicity, GIT and BBB permeability. The main pharmacokinetic parameters like volume of distribution, free fraction in plasma, total clearance, and half-life were predicted by previously derived models. Nine of the compounds bind to the enzyme with affinities from 0.517 to 0.735 µM, eight of them are non-toxic. All hits permeate GIT and BBB and bind extensively to plasma proteins. Most of them are low-clearance compounds. In total, seven of the 10 hits are promising for further lead optimisation. These are structures with ZINC IDs: 00220177, 44455618, 66142300, 71804814, 72065926, 96007907, and 97159977.

In Silico Design of Human IMPDH Inhibitors Using Pharmacophore Mapping and Molecular Docking Approaches

PubMed Central

Li, Rui-Juan; Wang, Ya-Li; Wang, Qing-He; Wang, Jian; Cheng, Mao-Sheng

2015-01-01

Inosine 5′-monophosphate dehydrogenase (IMPDH) is one of the crucial enzymes in the de novo biosynthesis of guanosine nucleotides. It has served as an attractive target in immunosuppressive, anticancer, antiviral, and antiparasitic therapeutic strategies. In this study, pharmacophore mapping and molecular docking approaches were employed to discover novel Homo sapiens IMPDH (hIMPDH) inhibitors. The Güner-Henry (GH) scoring method was used to evaluate the quality of generated pharmacophore hypotheses. One of the generated pharmacophore hypotheses was found to possess a GH score of 0.67. Ten potential compounds were selected from the ZINC database using a pharmacophore mapping approach and docked into the IMPDH active site. We find two hits (i.e., ZINC02090792 and ZINC00048033) that match well the optimal pharmacophore features used in this investigation, and it is found that they form interactions with key residues of IMPDH. We propose that these two hits are lead compounds for the development of novel hIMPDH inhibitors. PMID:25784957

The effect of dietary zinc - and polyphenols intake on DMBA-induced mammary tumorigenesis in rats

PubMed Central

2012-01-01

Background The aim of the study was to investigate the effect of dietary supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein, on the effectiveness of chemically induced mammary cancer and the changes in the content of selected elements (Zn, Cu, Mg, Fe, Ca) in tumors as compared with normal tissue of the mammary gland. Methods Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet and DMBA (7,12-dimethyl-1,2- benz[a]anthracene), were treated with zinc ions (Zn) or zinc ions + resveratrol (Zn + resveratrol) or zinc ions + genistein (Zn + genistein) via gavage for a period from 40 days until 20 weeks of age. The ICP-OES (inductively coupled plasma optical emission spectrometry) technique was used to analyze the following elements: magnesium, iron, zinc and calcium. Copper content in samples was estimated in an atomic absorption spectrophotometer. Results Regardless of the diet (standard; Zn; Zn + resveratrol; Zn + genistein), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn + resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. On the basis of quantitative analysis of selected elements we found - irrespectively of the diet applied - great accumulation of copper and iron, which are strongly prooxidative, with a simultaneous considerable decrease of the magnesium content in DMBA-induced mammary tumors. The combination of zinc supplementation with resveratrol resulted in particularly large differences in the amount of the investigated elements in tumors as compared with their content in normal tissue. Conclusions Diet supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein had no effect on the decreased copper level in tumor tissue and inhibited mammary carcinogenesis in the rat. Irrespectively of the applied diet, the development of the neoplastic process in rats resulted in changes of the iron and magnesium content in the cancerous tissue in comparison with the healthy mammary tissue. The application of combined diet supplementation with zinc ions and resveratrol considerably promoted the rate of carcinogenesis and increased the number of DMBA-induced mammary tumors. PMID:22507225

Palmate-like pentafoliata1 encodes a novel Cys(2)His(2) zinc finger transcription factor essential for compound leaf morphogenesis in Medicago truncatula

PubMed Central

2010-01-01

As the primary site for photosynthetic carbon fixation and the interface between plants and the environment, plant leaves play a key role in plant growth, biomass production and survival, and global carbon and oxygen cycles. Leaves can be simple with a single blade or compound with multiple units of blades known as leaflets. In a palmate-type compound leaf, leaflets are clustered at the tip of the leaf. In a pinnate-type compound leaf, on the other hand, leaflets are placed on a rachis in distance from each other. Higher orders of complexities such as bipinnate compound leaves of the “sensitive” plant, Mimosa pudica, also occur in nature. However, how different leaf morphologies are determined is still poorly understood. Medicago truncatula is a model legume closely related to alfalfa and soybean with trifoliate compound leaves. Recently, we have shown that Palmate-like Pentafoliata1 (PALM1) encodes a putative Cys(2) His(2) zinc finger transcription factor essential for compound leaf morphogenesis in M. truncatula. Here, we present our phylogenetic relationship analysis of PALM1 homologs from different species and demonstrate that PALM1 has transcriptional activity in the transactivation assay in yeast. PMID:20724826

The biological inorganic chemistry of zinc ions.

PubMed

Krężel, Artur; Maret, Wolfgang

2016-12-01

The solution and complexation chemistry of zinc ions is the basis for zinc biology. In living organisms, zinc is redox-inert and has only one valence state: Zn(II). Its coordination environment in proteins is limited by oxygen, nitrogen, and sulfur donors from the side chains of a few amino acids. In an estimated 10% of all human proteins, zinc has a catalytic or structural function and remains bound during the lifetime of the protein. However, in other proteins zinc ions bind reversibly with dissociation and association rates commensurate with the requirements in regulation, transport, transfer, sensing, signalling, and storage. In contrast to the extensive knowledge about zinc proteins, the coordination chemistry of the "mobile" zinc ions in these processes, i.e. when not bound to proteins, is virtually unexplored and the mechanisms of ligand exchange are poorly understood. Knowledge of the biological inorganic chemistry of zinc ions is essential for understanding its cellular biology and for designing complexes that deliver zinc to proteins and chelating agents that remove zinc from proteins, for detecting zinc ion species by qualitative and quantitative analysis, and for proper planning and execution of experiments involving zinc ions and nanoparticles such as zinc oxide (ZnO). In most investigations, reference is made to zinc or Zn 2+ without full appreciation of how biological zinc ions are buffered and how the d-block cation Zn 2+ differs from s-block cations such as Ca 2+ with regard to significantly higher affinity for ligands, preference for the donor atoms of ligands, and coordination dynamics. Zinc needs to be tightly controlled. The interaction with low molecular weight ligands such as water and inorganic and organic anions is highly relevant to its biology but in contrast to its coordination in proteins has not been discussed in the biochemical literature. From the discussion in this article, it is becoming evident that zinc ion speciation is important in zinc biochemistry and for biological recognition as a variety of low molecular weight zinc complexes have already been implicated in biological processes, e.g. with ATP, glutathione, citrate, ethylenediaminedisuccinic acid, nicotianamine, or bacillithiol. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Analysis of the effects of natural organic matter in zinc beneficiation

USDA-ARS?s Scientific Manuscript database

In this study, we present the analysis of the effects of Natural Organic Matter (NOM) in zinc beneficiation from abandoned mine tailings using bioleaching technologies. We used standardized Suwannee River Humic Acid (SRHA) as the NOM source to analyze the importance of the quality of the process wat...

Application of pyroelectric crystal and ionic liquid to the production of metal compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imashuku, Susumu; Imanishi, Akira; Kawai, Jun

2013-04-19

Zinc fluoride (ZnF{sub 2}) was deposited on a silicon substrate by changing temperature of a pyroelectric crystal of LiTaO{sub 3} on which ionic liquid (EMI-Tf{sub 2}N) containing zinc ions was dripped at 1 Pa. ZnF{sub 2} was also obtained by bombarding argon ions on EMI-Tf{sub 2}N containing zinc ions. From these results, it is concluded that EMI-Tf{sub 2}N containing zinc ions on the LiTaO{sub 3} crystal was evaporated on the silicon substrate by changing temperature of the LiTaO{sub 3} crystal in vacuum and that the evaporated EMI-Tf{sub 2}N containing metal zinc ions was decomposed to ZnF{sub 2} by the bombardmentmore » of electrons accelerated by the electric field between the LiTaO{sub 3} crystal and the silicon substrate.« less

Zinc in Entamoeba invadens.

NASA Technical Reports Server (NTRS)

Morgan, R. S.; Sattilaro, R. F.

1972-01-01

Atomic absorption spectroscopy, electron microprobe analysis, and dithizone staining of trophozoites and cysts of Entamoeba invadens demonstrate that these cells have a high concentration of zinc (approximately one picogram per cell or 1% of their dry weight). In the cysts of this organism, the zinc is confined to the chromatoid bodies, which previous work has shown to contain crystals of ribosomes. The chemical state and function of this zinc are unknown.

Reinvestigation of growth of 'L-valine zinc sulphate' crystal.

PubMed

Srinivasan, Bikshandarkoil R; Jyai, Rita N

2014-01-01

A reinvestigation of the growth of l-valine zinc sulphate crystal is reported. The slow evaporation of an aqueous solution containing l-valine and zinc sulphate heptahydrate results in the fractional crystallization of l-valine and not the organic inorganic hybrid nonlinear optical l-valine zinc sulphate crystal, as reported by Puhal Raj and Ramachandra Raja (2012). Copyright © 2013 Elsevier B.V. All rights reserved.

Implications of effluent organic matter and its hydrophilic fraction on zinc(II) complexation in rivers under strong urban pressure: aromaticity as an inaccurate indicator of DOM-metal binding.

PubMed

Louis, Yoann; Pernet-Coudrier, Benoît; Varrault, Gilles

2014-08-15

The zinc binding characteristics of dissolved organic matter (DOM) fractions from the Seine River Basin were studied after being separated and extracted according to their polarity: hydrophobic, transphilic, and hydrophilic. The applied experimental methodology was based on a determination of labile zinc species by means of differential pulse anodic stripping voltammetry (DPASV) at increasing concentrations of total zinc on a logarithmic scale and at fixed levels of: pH, ionic strength, and temperature. Fitting the DOM fractions with two discrete classes of ligands successfully allowed determining the conditional zinc binding constants (Ki) as well as total ligand density (LiT). The binding constants obtained for each DOM fraction were then compared and discussed with respect to the hydrophobic/hydrophilic nature and sample origin. Results highlighted a strong complexation of zinc to the effluent organic matter and especially the most hydrophilic fraction, which also displayed a very low specific UV absorbance. Although the biotic ligand model takes into account the quality of DOM through UV absorbance in the predictions of metal bioavailability and toxicity, this correction is not efficient for urban waters. Copyright © 2014 Elsevier B.V. All rights reserved.

In vitro effects of simultaneous exposure to platinum and cadmium on the activity of antioxidant enzymes and DNA damage and potential protective effects of selenium and zinc.

PubMed

Tariba, Blanka; Živković, Tanja; Gajski, Goran; Gerić, Marko; Gluščić, Valentina; Garaj-Vrhovac, Vera; Peraica, Maja; Pizent, Alica

2017-04-01

Circulating platinum (Pt) is detectable in the blood of Pt-treated cancer patients for over a decade after the treatment. Prolonged exposure to Pt, in combination with adverse compounds from nutrition and lifestyle, such as cadmium (Cd), could increase the risk from second cancers. The aim of this study was to investigate the effects of simultaneous exposure to Cd- and Pt-compounds on oxidative and DNA damage and the possible protective effects of zinc (Zn) and selenium (Se). The aqueous solutions of PtCl 4 , CdCl 2  ×   H 2 O, ZnCl 2 and Na 2 SeO 3 were added, alone or in combination, to whole blood and isolated erythrocytes to produce the final concentrations of 2000 μg/L of Pt, 8 μg/L of Cd, 100 μg/L of Se, and 1000 μg/L of Zn. The activity of copper, zinc-superoxide dismutase, glutathione peroxidase and glutathione in whole blood was determined after 1 h exposure in in vitro conditions. The induction of DNA strand-breaks in human peripheral blood leukocytes was determined with the alkaline comet assay after 24 h exposure. Exposure to Pt and/or Cd decreased the activities of antioxidant enzymes and elevated DNA damage compared to control. A statistically significant change in the activity of both enzymes and in the induction of DNA strand-breaks was observed in the cells treated with Pt + Cd combination, while the addition of Se and/or Zn resulted in partial recovery of these effects. The results indicate that combined exposure to Pt and Cd could disrupt antioxidant protection of the organism and increase DNA damage, whereas Se and Zn could partially ameliorate these harmful effects.

Swallowing sunscreen

MedlinePlus

... any of these ingredients: Cinnamates Padimate-O Salicylates (aspirin-like compounds) Zinc oxide Sunscreen may also contain ... from salicylates could cause a condition similar to aspirin overdose .

Enzymatic transformation of hydrocarbons by methanotrophic organisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, R.N.; Hou, C.T.

Soluble methane monooxygenase from a facultative methane-utilizing organism, Methylobacterium sp. CRL-26 or R6, catalyzed the NAD(P)H-dependent epoxidation/hydroxylation of a variety of hydrocarbons, including terminal alkenes, internal alkenes, substituted alkenes, branch-chain alkenes, alkanes (C1-C8), substituted alkanes, branch-chain alkanes, carbon monoxide, ether, cyclic and aromatic compounds. The NAD -linked dehydrogenases such as formate dehydrogenase or secondary alcohol dehydrogenase in the presence of formate or secondary alcohol, respectively, regenerated NAD/NADH required for the methane monooxygenase in a coupled enzymes reactions. Oxidation of secondary alcohols to the corresponding methylketones in methanotrophs is catalyzed by an NAD -dependent, zinc-containing, secondary alcohol hydrogenase. Primary alcohols weremore » oxidized to the corresponding aldehydes by a phenazine methosulfate-dependent, pyrollo quinoline quinone (methoxatin or PQQ) containing, methanol dehydrogenase. Oxidation of aldehydes (C1 to C10) to the corresponding carboxylic acids is catalyzed by a heme-containing aldehyde dehydrogenase. Methanotrophs have been considered potentially useful for single cell protein (SCP), amino acids, and biopolymer production at the expense of growth on cheap and readily available C1 compounds. 80 references, 1 figure, 6 tables.« less

Polyorganometallosiloxane-2- or -4-pyridine coatings

DOEpatents

Sugama, T.

1997-12-30

A new family of polyorganometallosiloxane-2- or -4-pyridine compounds are provided for corrosion resistant coatings on light metals such as aluminum, magnesium, zinc, steel and their alloys. The novel compounds contain backbones modified by metal alkoxides, metallocenes and metallophthalocyanates where the metal is Zr, Ti, Mo, V, Hf, Nb, Si, B and combinations thereof. Methods of making the new compounds are also provided. 13 figs.

1,2-Dibenzyltetradimethylamido-Dimolybdenum and -Ditungsten (M=M) Compounds and Their Reactions with Carbon Dioxide and 1,3-Diaryltriazines. A Radical Difference.

DTIC Science & Technology

1982-07-07

solution of a mixture of these Mo2- and MoW-containing compounds selectively precipitated the heterobimetallic single elec- tron oxidation product MoW...3.5 and reduction, using 0$ powdered zinc in acetonitrile at 25°C, yielded the heterobimetallic quadruply bonded compound MoW(O2CBu t )4. Katovic, V

Biological activities of phthalocyanines--XVI. Tetrahydroxy- and tetraalkylhydroxy zinc phthalocyanines. Effect of alkyl chain length on in vitro and in vivo photodynamic activities.

PubMed Central

Boyle, R. W.; Leznoff, C. C.; van Lier, J. E.

1993-01-01

Zinc phthalocyanine substituted with four hydroxyl groups attached to the macrocycle, either directly or via spacer chains of three or six carbon atoms, were tested for their photodynamic ability to inactivate Chinese hamster lung fibroblasts (line V-79) in vitro, and to induce regression of EMT-6 tumours grown subcutaneously in Balb/c mice. Their potential to inflict direct cell killing during photodynamic therapy was investigated by examining vascular stasis immediately following photoirradiation using fluorescein as a marker, and also by an in vivo/in vitro EMT-6 cell survival assay. Both of the tetraalkylhydroxy substituted zinc phthalocyanines are effective photodynamic sensitisers in vivo with the tetrapropylhydroxy compound exhibiting about twice the activity of the tetrahexylhydroxy analogue. The differences in activities were accentuated in vitro, the tetrapropylhydroxy compound was two orders of magnitude more potent than the tetrahexylhydroxy analogue in photoinactivating V-79 cells. The tetrahydroxy compound lacking spacer chains failed to exhibit photodynamic activity in either system. Tumour response with the active compounds was preceded by vascular stasis immediate following irradiation which suggests, together with the absence of activity in the in vivo/in vitro assay, that tumour regression involves an indirect response to the photodynamic action rather than direct cell killing. These data demonstrate the importance of the spatial orientation of functional groups around the macrocycle of photosensitisers for their efficacy in the photodynamic therapy of cancer. PMID:8512803

A computationally identified compound antagonizes excess FGF-23 signaling in renal tubules and a mouse model of hypophosphatemia

DOE PAGES

Xiao, Zhousheng; Riccardi, Demian; Velazquez, Hector A.; ...

2016-11-22

Fibroblast growth factor–23 (FGF-23) interacts with a binary receptor complex composed of α-Klotho (α-KL) and FGF receptors (FGFRs) to regulate phosphate and vitamin D metabolism in the kidney. Excess FGF-23 production, which causes hypophosphatemia, is genetically inherited or occurs with chronic kidney disease. Among other symptoms, hypophosphatemia causes vitamin D deficiency and the bone-softening disorder rickets. Current therapeutics that target the receptor complex have limited utility clinically. In this paper, using a computationally driven, structure-based, ensemble docking and virtual high-throughput screening approach, we identified four novel compounds predicted to selectively inhibit FGF-23–induced activation of the FGFR/α-KL complex. Additional modeling andmore » functional analysis found that Zinc13407541 bound to FGF-23 and disrupted its interaction with the FGFR1/α-KL complex; experiments in a heterologous cell expression system showed that Zinc13407541 selectivity inhibited α-KL–dependent FGF-23 signaling. Zinc13407541 also inhibited FGF-23 signaling in isolated renal tubules ex vivo and partially reversed the hypophosphatemic effects of excess FGF-23 in a mouse model. Finally, these chemical probes provide a platform to develop lead compounds to treat disorders caused by excess FGF-23.« less

A computationally identified compound antagonizes excess FGF-23 signaling in renal tubules and a mouse model of hypophosphatemia.

PubMed

Xiao, Zhousheng; Riccardi, Demian; Velazquez, Hector A; Chin, Ai L; Yates, Charles R; Carrick, Jesse D; Smith, Jeremy C; Baudry, Jerome; Quarles, L Darryl

2016-11-22

Fibroblast growth factor-23 (FGF-23) interacts with a binary receptor complex composed of α-Klotho (α-KL) and FGF receptors (FGFRs) to regulate phosphate and vitamin D metabolism in the kidney. Excess FGF-23 production, which causes hypophosphatemia, is genetically inherited or occurs with chronic kidney disease. Among other symptoms, hypophosphatemia causes vitamin D deficiency and the bone-softening disorder rickets. Current therapeutics that target the receptor complex have limited utility clinically. Using a computationally driven, structure-based, ensemble docking and virtual high-throughput screening approach, we identified four novel compounds predicted to selectively inhibit FGF-23-induced activation of the FGFR/α-KL complex. Additional modeling and functional analysis found that Zinc13407541 bound to FGF-23 and disrupted its interaction with the FGFR1/α-KL complex; experiments in a heterologous cell expression system showed that Zinc13407541 selectivity inhibited α-KL-dependent FGF-23 signaling. Zinc13407541 also inhibited FGF-23 signaling in isolated renal tubules ex vivo and partially reversed the hypophosphatemic effects of excess FGF-23 in a mouse model. These chemical probes provide a platform to develop lead compounds to treat disorders caused by excess FGF-23. Copyright © 2016, American Association for the Advancement of Science.

A computationally identified compound antagonizes excess FGF-23 signaling in renal tubules and a mouse model of hypophosphatemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Zhousheng; Riccardi, Demian; Velazquez, Hector A.

Fibroblast growth factor–23 (FGF-23) interacts with a binary receptor complex composed of α-Klotho (α-KL) and FGF receptors (FGFRs) to regulate phosphate and vitamin D metabolism in the kidney. Excess FGF-23 production, which causes hypophosphatemia, is genetically inherited or occurs with chronic kidney disease. Among other symptoms, hypophosphatemia causes vitamin D deficiency and the bone-softening disorder rickets. Current therapeutics that target the receptor complex have limited utility clinically. In this paper, using a computationally driven, structure-based, ensemble docking and virtual high-throughput screening approach, we identified four novel compounds predicted to selectively inhibit FGF-23–induced activation of the FGFR/α-KL complex. Additional modeling andmore » functional analysis found that Zinc13407541 bound to FGF-23 and disrupted its interaction with the FGFR1/α-KL complex; experiments in a heterologous cell expression system showed that Zinc13407541 selectivity inhibited α-KL–dependent FGF-23 signaling. Zinc13407541 also inhibited FGF-23 signaling in isolated renal tubules ex vivo and partially reversed the hypophosphatemic effects of excess FGF-23 in a mouse model. Finally, these chemical probes provide a platform to develop lead compounds to treat disorders caused by excess FGF-23.« less

Inhibition of orally produced volatile sulfur compounds by zinc, chlorhexidine or cetylpyridinium chloride--effect of concentration.

PubMed

Young, Alix; Jonski, Grazyna; Rölla, Gunnar

2003-10-01

Zinc ions, chlorhexidine (CHX) and cetylpyridinium chloride (CPC) are all known to inhibit production of volatile sulfur compounds (VSCs). The objective was to examine the anti-VSC dose-response effects of each of the above agents. Oral malodor was induced in 13 test subjects using the cysteine challenge method. The oral VSC response to rinses with 6 mm l-cysteine (pH 7.2) before and 1, 2 and 3 h after rinsing with zinc ions (Zn2+: 0.1, 0.3 and 1.0%), CHX and CPC (0.025 and 0.2%) was measured. Mouth air was analysed for VSC by gas chromatography (GC) according to current methodology. Zinc had a marked dose- and time-dependent anti-VSC effect. Zinc at 1% concentration had a somewhat unpleasant taste, whereas the lowest concentration was found acceptable. Chlorhexidine maintained a moderate anti-VSC effect over time. At 3 h, 0.2% CHX was the most effective agent but tasted relatively unpleasant. Cetylpyridinium at a concentration of 0.2% was only marginally more effective than 0.025% CHX over the 3 h, while 0.025% CPC had no better anti-VSC effect than water at both 2 h and 3 h. It was concluded that the three test agents demonstrated different anti-VSC kinetics. Although Zn had the best anti-VSC effect at 1 h, 0.2% CHX was at least as effective as 1% Zn at 3 h, most likely as a result of its unique substantivity.

Efficient visible light photocatalysis of benzene, toluene, ethylbenzene and xylene (BTEX) in aqueous solutions using supported zinc oxide nanorods.

PubMed

Al-Sabahi, Jamal; Bora, Tanujjal; Al-Abri, Mohammed; Dutta, Joydeep

2017-01-01

Benzene, toluene, ethylbenzene and xylenes (BTEX) are some of the common environmental pollutants originating mainly from oil and gas industries, which are toxic to human as well as other living organisms in the ecosystem. Here we investigate photocatalytic degradation of BTEX under visible light irradiation using supported zinc oxide (ZnO) nanorods grown on glass substrates using a microwave assisted hydrothermal method. ZnO nanorods were characterized by electron microscopy, X-ray diffraction (XRD), specific surface area, UV/visible absorption and photoluminescence spectroscopy. Visible light photocatalytic degradation products of BTEX are studied for individual components using gas chromatograph/mass spectrometer (GC/MS). ZnO nanorods with significant amount of electronic defect states, due to the fast crystallization of the nanorods under microwave irradiation, exhibited efficient degradation of BTEX under visible light, degrading more than 80% of the individual BTEX components in 180 minutes. Effect of initial concentration of BTEX as individual components is also probed and the photocatalytic activity of the ZnO nanorods in different conditions is explored. Formation of intermediate byproducts such as phenol, benzyl alcohol, benzaldehyde and benzoic acid were confirmed by our HPLC analysis which could be due to the photocatalytic degradation of BTEX. Carbon dioxide was evaluated and showed an increasing pattern over time indicating the mineralization process confirming the conversion of toxic organic compounds into benign products.

Low-temperature processed Ga-doped ZnO coatings from colloidal inks.

PubMed

Della Gaspera, Enrico; Bersani, Marco; Cittadini, Michela; Guglielmi, Massimo; Pagani, Diego; Noriega, Rodrigo; Mehra, Saahil; Salleo, Alberto; Martucci, Alessandro

2013-03-06

We present a new colloidal synthesis of gallium-doped zinc oxide nanocrystals that are transparent in the visible and absorb in the near-infrared. Thermal decomposition of zinc stearate and gallium nitrate after hot injection of the precursors in a mixture of organic amines leads to nanocrystals with tunable properties according to gallium amount. Substitutional Ga(3+) ions trigger a plasmonic resonance in the infrared region resulting from an increase in the free electrons concentration. These nanocrystals can be deposited by spin coating, drop casting, and spray coating resulting in homogeneous and high-quality thin films. The optical transmission of the Ga-ZnO nanoparticle assemblies in the visible is greater than 90%, and at the same time, the near-infrared absorption of the nanocrystals is maintained in the films as well. Several strategies to improve the films electrical and optical properties have been presented, such as UV treatments to remove the organic compounds responsible for the observed interparticle resistance and reducing atmosphere treatments on both colloidal solutions and thin films to increase the free carriers concentration, enhancing electrical conductivity and infrared absorption. The electrical resistance of the nanoparticle assemblies is about 30 kΩ/sq for the as-deposited, UV-exposed films, and it drops down to 300 Ω/sq after annealing in forming gas at 450 °C, comparable with state of the art tin-doped indium oxide coatings deposited from nanocrystal inks.

Synthesis and binding properties of arylethyne-linked porphyrin-zinc complexes for organic electronics applications.

PubMed

Reainthippayasakul, W; Paosawatyanyong, B; Bhanthumnavin, W

2013-05-01

Conjugated meso-alkynyl 5,15-dimesitylporphyrin metal complexes have been synthesized by Sonogashira coupling reaction in good yields. Alkynyl groups were chosen as a link at the meso positions in order to extend the pi-conjugated length of porphyrin rings. These synthesized porphyrin derivatives were characterized by 1H NMR spectroscopy and MALDI-TOF mass spectrometry. Moreover, UV-visible spectroscopy and fluorescence spectroscopy were also used to investigate their photophysical properties. It has been demonstrated that central metal ions as well as meso substituents on porphyrin rings affected the electronic absorption and emission spectra of the compounds. Spectroscopic results revealed that alkyne-linked porphyrin metal complexes showed higher pi-conjugation compared with porphyrin building blocks resulting in red shifts in both absorption and emission spectra. Coordination properties of synthesized porphyrins were preliminarily investigated by UV-visible absorption and fluorescence emission spectroscopic titration with pyridine as axial ligand. The formation of porphyrin-pyridine complexes resulted in significant red shifts in absorption spectra and decrease of fluorescence intensity in emission spectra. Moreover, the 1H NMR titration experiments suggested that central metal ions play an important role to coordinate with pyridine and the coordination of porphyrin zinc(II) complex with pyridine occur in a 1:1 ratio. From these spectroscopic results, alkyne-linked porphyrin metal complexes offer potential applications as materials for optical organic nanosensors.

Efficient visible light photocatalysis of benzene, toluene, ethylbenzene and xylene (BTEX) in aqueous solutions using supported zinc oxide nanorods

PubMed Central

Bora, Tanujjal; Al-Abri, Mohammed; Dutta, Joydeep

2017-01-01

Benzene, toluene, ethylbenzene and xylenes (BTEX) are some of the common environmental pollutants originating mainly from oil and gas industries, which are toxic to human as well as other living organisms in the ecosystem. Here we investigate photocatalytic degradation of BTEX under visible light irradiation using supported zinc oxide (ZnO) nanorods grown on glass substrates using a microwave assisted hydrothermal method. ZnO nanorods were characterized by electron microscopy, X-ray diffraction (XRD), specific surface area, UV/visible absorption and photoluminescence spectroscopy. Visible light photocatalytic degradation products of BTEX are studied for individual components using gas chromatograph/mass spectrometer (GC/MS). ZnO nanorods with significant amount of electronic defect states, due to the fast crystallization of the nanorods under microwave irradiation, exhibited efficient degradation of BTEX under visible light, degrading more than 80% of the individual BTEX components in 180 minutes. Effect of initial concentration of BTEX as individual components is also probed and the photocatalytic activity of the ZnO nanorods in different conditions is explored. Formation of intermediate byproducts such as phenol, benzyl alcohol, benzaldehyde and benzoic acid were confirmed by our HPLC analysis which could be due to the photocatalytic degradation of BTEX. Carbon dioxide was evaluated and showed an increasing pattern over time indicating the mineralization process confirming the conversion of toxic organic compounds into benign products. PMID:29261711

Synthesis and characterization of sulfate and dodecylbenzenesulfonate intercalated zinc iron layered double hydroxides by one-step coprecipitation route

NASA Astrophysics Data System (ADS)

Zhang, Hui; Wen, Xing; Wang, Yingxia

2007-05-01

Inorganic sulfate- and organic dodecylbenzenesulfonate (DBS)-intercalated zinc-iron layered double hydroxides (LDHs) materials were prepared by one-step coprecipitation method from a mixed salt solutions containing Zn(II), Fe(II) and Fe(III) salts. The as-prepared samples have been characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature nitrogen adsorption, scanning electron microscopy (SEM), inductively coupled plasma emission spectroscopy (ICP), and Mössbauer spectroscopy (MS). The XRD analyses demonstrate the typical LDH-like layered structural characteristics of both products. The room temperature MS results reveal the characteristics of both the Fe(II) and Fe(III) species for SO 42--containing product, while only the Fe(III) characteristic for DBS-containing one. The combination characterization results and Rietveld analysis illustrate that the SO 42--containing product possesses the Green Rust two (GR2)-like crystal structure with an approximate chemical composition of [Zn 0.435·Fe II0.094·Fe III0.470·(OH) 2]·(SO 42-) 0.235·1.0H 2O, while the DBS-containing one exhibits the common LDH compound-like structure. The contact angle measurement indicates the evident hydrophobic properties of DBS-containing nanocomposite, compared with SO 42--containing product, due to the modification of the internal and external surface of LDHs by the organic hydrophobic chain of DBS.

The effects of chronological age and size on toxicity of zinc to juvenile brown trout

EPA Science Inventory

A series of toxicity tests were conducted to investigate the role of chronological age and organism weight on zinc tolerance in juvenile brown trout (Salmo trutta). Four different incubation temperatures were used to control the maturation of the juveniles prior to zinc exposure...

Performance characteristics of zinc-rich coatings applied to carbon steel

NASA Technical Reports Server (NTRS)

Paton, W. J.

1973-01-01

A program was conducted to evaluate the performance of topcoated and untopcoated zinc-rich coatings. Sacrificial coatings of this type are required for protecting carbon steel structures from the aggressive KSC sea coast environment. A total of 59 commercially available zinc-rich coatings and 47 topcoated materials were exposed for an 18-month period. Test panels were placed in special racks placed approximately 30.5 m (100 feet) above the high tide line at the KSC Corrosion Test Site. Laboratory tests to determine the temperature resistance, abrasion resistance, and adhesion of the untopcoated zinc-rich coatings were also performed. It has been concluded that: (1) The inorganic types of zinc-rich coatings are far superior to the organic types in the KSC environment. (2) Organic zinc-rich coatings applied at 0.1 - 0.15 mm (4-6 mils) film thickness provide better corrosion protection than when applied at the manufacturers' recommended nominal film thickness of .08 mm (3 mils). (3) Topcoats are not necessary, or even desirable, when used in conjunction with zinc-rich coatings in the KSC environment. (4) Some types of inorganic zinc-rich coatings require an extended outdoor weathering period in order to obtain adequate mechanical properties. and (5) A properly formulated inorganic zinc-rich coating is not affected by a 24-hour thermal exposure to 400 C (752 F).

Synergistic Effects Between Phosphonium-Alkylphosphate Ionic Liquids and Zinc Dialkyldithiophosphate (ZDDP) as Lubricant Additives

DOE PAGES

Qu, Jun; Barnhill, William C.; Luo, Huimin; ...

2015-07-14

Unique synergistic effects between phosphonium-alkylphosphate ionic liquids and zinc dialkyldithiophosphate (ZDDP) are discovered when used together as lubricant additives, resulting in significant friction and wear reduction along with distinct tribofilm composition and mechanical properties. The synergism is attributed to the 30-70× higher-than-nominal concentrations of hypothetical new compounds (via anion exchange between IL and ZDDP) on the fluid surface/interface.

Modulation of ruminal and intestinal fermentation by medicinal plants and zinc from different sources.

PubMed

Váradyová, Zora; Mravčáková, Dominika; Holodová, Monika; Grešáková, Ľubomira; Pisarčíková, Jana; Barszcz, Marcin; Taciak, Marcin; Tuśnio, Anna; Kišidayová, Svetlana; Čobanová, Klaudia

2018-06-14

Two experiments were conducted on sheep to determine the effect of dietary supplementation with zinc and a medicinal plant mixture on haematological parameters and microbial activity in the rumen and large intestine. In Experiment 1, 24 male lambs were randomly divided into four groups: One group was fed an unsupplemented basal diet (control), and three groups were fed a diet supplemented with 70 mg Zn/kg diet in the form of Zn sulphate (ZnSO 4 ), a Zn-chelate of glycine hydrate (Zn-Gly) or a Zn-proteinate (Zn-Pro), for five months. The ruminal content was collected separately from each lamb, and batch cultures of ruminal fluid were incubated in vitro with mixture of medicinal plants (Mix) with different roughage:concentrate ratios (800:200 and 400:600, w/w). Bioactive compounds in Mix were quantified by UPLC/MS/MS. In Experiment 2, four sheep were fed a diet consisting of meadow hay and barley grain (400:600, w/w), with Zn-Gly (70 mg Zn/kg diet), Mix (10% replacement of meadow hay) or Zn-Gly and Mix (Zn-Gly-Mix) as supplements in a Latin square design. Mix decreased total gas (p < 0.001) and methane (p < 0.01) production in vitro. In Experiment 1, caecal isobutyrate and isovalerate concentrations varied among the dietary treatments (p < 0.01). The isovalerate concentration of the zinc-supplemented groups in the distal colon was higher (p < 0.001) compared with the control. In Experiment 2, the molar proportion of isobutyrate was the highest in the faeces of the sheep fed the diet with Zn-Gly-Mix (p < 0.01). The plasma zinc concentration was higher in the groups fed a diet supplemented with zinc (p < 0.001). The haematological profile and antioxidant status did not differ between the dietary groups (p > 0.05). The diets containing medicinal plants and organic zinc thus helped to modulate the characteristics of fermentation in ruminants. © 2018 Blackwell Verlag GmbH.

Synthesis of asymmetric zinc(II) phthalocyanines with two different functional groups & spectroscopic properties and photodynamic activity for photodynamic therapy.

PubMed

Göksel, Meltem

2016-09-15

Zinc(II) phthalocyanine containing [2-(tert-butoxycarbonyl)amino]ethoxy and iodine groups (A and B), as well as their deprotected mono-amino and tri-iodine zinc(II) phthalocyanine (2) were obtained. This structure surrounds by substituents with functional groups. From this perspective it can be used a starting material for many reactions and applications, such as sonogashira coupling, carbodiimide coupling. An example of a first diversification reaction of this compound was obtained with conjugation of a biotin. Asymmetrically biotin conjugated and heavy atom bearing zinc(II) phthalocyanine (3) were synthesized characterized for the first time and photophysical, photochemical and photobiological properties of these phthalocyanines were compared in this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metallohydrolase biomimetics with catalytic and structural flexibility.

PubMed

Mendes, Luisa L; Englert, Daniel; Fernandes, Christiane; Gahan, Lawrence R; Schenk, Gerhard; Horn, Adolfo

2016-11-22

The structural and functional properties of zinc(ii) complexes of two nitrogen rich polydentate ligands, HTPDP = 1,3-bis(bis-pyridin-2-ylmethylamino)propan-2-ol and HTPPNOL = N,N,N'-tris-(2-pyridylmethyl)-1,3-diaminopropan-2-ol, are compared. HTPDP is a hepta-dentate ligand with four pyridyl groups attached to a 1,3-diaminopropan-2-ol backbone while HTPPNOL contains only three pyridyl groups. In reactions with Zn(ClO 4 ) 2 , HTPDP forms a dinuclear zinc compound [Zn 2 (TPDP)(OAc)](ClO 4 ) 2 , 1. On the other hand, mononuclear [Zn(HTPPNOL)](ClO 4 ) 2 , 2, and tetranuclear [Zn 4 (TPPNOL) 2 (OAc) 3 ](ClO 4 ) 3 , 3, complexes were isolated with the ligand HTPPNOL. Kinetic measurements with the substrate bis(2,4-dinitrophenyl)phosphate (BDNPP) revealed that compound 1 (k cat = 31.4 × 10 -3 min -1 ) is more reactive than 3 (k cat = 7.7 × 10 -3 min -1 ) at pH = 8.5, whilst the mononuclear compound 2 is inactive. Compound 1 displays a typical steady-state kinetic behaviour, while compound 3 exhibits steady-state behaviour only ∼120 s after starting the reaction, preceded by a burst-phase. 31 P NMR studies confirm that 1 can promote the hydrolysis of both ester bonds in BDNPP, generating the monoester DNPP and inorganic phosphate in the process. In contrast, DNPP is not a substrate for 3. The crystal structure of the complex formed by 3 and DNPP reveals the formation of a tetranuclear zinc complex [Zn 4 (TPPNOL) 2 (DNPP) 2 ](ClO 4 ) 2 , 4, in which the phosphate moiety of DNPP adopts an unusual tridentate μ-η 1 :η 1 :η 1 coordination mode.

Zinc complexes supported by methyl salicylato ligands: synthesis, structure, and application in ring-opening polymerization of L-lactide.

PubMed

Petrus, Rafał; Sobota, Piotr

2013-10-14

Two novel zinc alkoxides supported by chelating methyl salicylato (MesalO; MesalOH = methyl salicylate) ligands were successfully synthesized and characterized. Reaction of MesalOH with ZnEt2 (2:1) gives a tetranuclear cluster [Zn(MesalO)2]4 (1), which by addition of pyridine is transformed to the mononuclear compound [Zn(MesalO)2(py)2] (2). Compounds 1 and 2 were characterized by elemental analysis, NMR, IR, and single crystal X-ray diffraction. The catalytic activity of both compounds was tested for the ring-opening polymerization (ROP) of L-lactide (L-LA). It was found that compounds 1 and 2 are efficient initiators of the ROP of L-LA, yielding cyclic PLLA with weight average molecular weights up to 100 kDa for 2. The treatment of 2 with 1 equiv. of BnOH in toluene afforded a dimeric compound [Zn(OBn)(MesalO)(py)]2 (3). The addition of L-LA to a combination of 1 and 4 equiv. of BnOH in THF or 2 and 1 equiv. of BnOH in toluene led to the rapid and efficient generation of PLLA with end-capped BnO groups.

[Exposure to metal compounds in occupational galvanic processes].

PubMed

Surgiewicz, Jolanta; Domański, Wojciech

2006-01-01

Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.

5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones: Zinc triflate-catalyzed one-pot multi-component synthesis, X-ray crystal structure and anti-inflammatory activity

NASA Astrophysics Data System (ADS)

Essid, Idris; Lahbib, Karima; Kaminsky, Werner; Ben Nasr, Cherif; Touil, Soufiane

2017-08-01

Herein we report a simple and efficient one-pot three-component synthesis of 5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones, through the zinc triflate-catalyzed Biginelli-type reaction of β-ketophosphonates, aldehydes and urea. The compounds obtained were characterized by various spectroscopic tools including IR, NMR (1H, 31P, 13C) spectroscopy, mass spectrometry and single crystal X-ray diffraction. All the synthesized compounds were screened, for the first time, for anti-inflammatory activity by carrageenan-induced hind paw edema method, using female Wister rats and they showed significant anti-inflammatory activity in some cases higher than the standard indomethacin.

Development of Thioaryl-Based Matrix Metalloproteinase-12 Inhibitors with Alternative Zinc-Binding Groups: Synthesis, Potentiometric, NMR, and Crystallographic Studies.

PubMed

Nuti, Elisa; Cuffaro, Doretta; Bernardini, Elisa; Camodeca, Caterina; Panelli, Laura; Chaves, Sílvia; Ciccone, Lidia; Tepshi, Livia; Vera, Laura; Orlandini, Elisabetta; Nencetti, Susanna; Stura, Enrico A; Santos, M Amélia; Dive, Vincent; Rossello, Armando

2018-05-24

Matrix metalloproteinase-12 (MMP-12) selective inhibitors could play a role in the treatment of lung inflammatory and cardiovascular diseases. In the present study, the previously reported 4-methoxybiphenylsulfonyl hydroxamate and carboxylate based inhibitors (1b and 2b) were modified to enhance their selectivity for MMP-12. In the newly synthesized thioaryl derivatives, the nature of the zinc binding group (ZBG) and the sulfur oxidation state were changed. Biological assays carried out in vitro on human MMPs with the resulting compounds led to identification of a sulfide, 4a, bearing an N-1-hydroxypiperidine-2,6-dione (HPD) group as new ZBG. Compound 4a is a promising hit compound since it displayed a nanomolar affinity for MMP-12 with a marked selectivity over MMP-9, MMP-1, and MMP-14. Solution complexation studies with Zn 2+ were performed to characterize the chelating abilities of the new compounds and confirmed the bidentate binding mode of HPD derivatives. X-ray crystallography studies using MMP-12 and MMP-9 catalytic domains were carried out to rationalize the biological results.

Generation of the first structure-based pharmacophore model containing a selective "zinc binding group" feature to identify potential glyoxalase-1 inhibitors.

PubMed

Al-Balas, Qosay; Hassan, Mohammad; Al-Oudat, Buthina; Alzoubi, Hassan; Mhaidat, Nizar; Almaaytah, Ammar

2012-11-22

Within this study, a unique 3D structure-based pharmacophore model of the enzyme glyoxalase-1 (Glo-1) has been revealed. Glo-1 is considered a zinc metalloenzyme in which the inhibitor binding with zinc atom at the active site is crucial. To our knowledge, this is the first pharmacophore model that has a selective feature for a "zinc binding group" which has been customized within the structure-based pharmacophore model of Glo-1 to extract ligands that possess functional groups able to bind zinc atom solely from database screening. In addition, an extensive 2D similarity search using three diverse similarity techniques (Tanimoto, Dice, Cosine) has been performed over the commercially available "Zinc Clean Drug-Like Database" that contains around 10 million compounds to help find suitable inhibitors for this enzyme based on known inhibitors from the literature. The resultant hits were mapped over the structure based pharmacophore and the successful hits were further docked using three docking programs with different pose fitting and scoring techniques (GOLD, LibDock, CDOCKER). Nine candidates were suggested to be novel Glo-1 inhibitors containing the "zinc binding group" with the highest consensus scoring from docking.

Differential Regulation by Organic Compounds and Heavy Metals of Multiple Laccase Genes in the Aquatic Hyphomycete Clavariopsis aquatica

PubMed Central

Solé, Magali; Müller, Ines; Pecyna, Marek J.; Fetzer, Ingo; Harms, Hauke

2012-01-01

To advance the understanding of the molecular mechanisms controlling microbial activities involved in carbon cycling and mitigation of environmental pollution in freshwaters, the influence of heavy metals and natural as well as xenobiotic organic compounds on laccase gene expression was quantified using quantitative real-time PCR (qRT-PCR) in an exclusively aquatic fungus (the aquatic hyphomycete Clavariopsis aquatica) for the first time. Five putative laccase genes (lcc1 to lcc5) identified in C. aquatica were differentially expressed in response to the fungal growth stage and potential laccase inducers, with certain genes being upregulated by, e.g., the lignocellulose breakdown product vanillic acid, the endocrine disruptor technical nonylphenol, manganese, and zinc. lcc4 is inducible by vanillic acid and most likely encodes an extracellular laccase already excreted during the trophophase of the organism, suggesting a function during fungal substrate colonization. Surprisingly, unlike many laccases of terrestrial fungi, none of the C. aquatica laccase genes was found to be upregulated by copper. However, copper strongly increases extracellular laccase activity in C. aquatica, possibly due to stabilization of the copper-containing catalytic center of the enzyme. Copper was found to half-saturate laccase activity already at about 1.8 μM, in favor of a fungal adaptation to low copper concentrations of aquatic habitats. PMID:22544244

The Components of the Unique Zur Regulon of Cupriavidus metallidurans Mediate Cytoplasmic Zinc Handling

PubMed Central

Bütof, Lucy; Schmidt-Vogler, Christopher; Herzberg, Martin; Große, Cornelia

2017-01-01

ABSTRACT Zinc is an essential trace element, yet it is toxic at high concentrations. In the betaproteobacterium Cupriavidus metallidurans, the highly efficient removal of surplus zinc from the periplasm is responsible for the outstanding metal resistance of the organism. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans has the secondary zinc importer ZupT of the zinc-regulated transporter, iron-regulated transporter (ZRT/IRT)-like protein (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes with exposure to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δzur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region by use of a truncation assay. The motif was used to predict possible Zur boxes upstream of Zur regulon members. The binding of Zur to these boxes was confirmed. Two Zur boxes upstream of the cobW1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW2, cobW3, and zupT permitted both low expression levels of these genes and their upregulation under conditions of zinc starvation. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans, where the periplasm is responsible for the removal of surplus zinc, cytoplasmic components are responsible for the management of zinc as an essential cofactor, and the two compartments are connected by ZupT. IMPORTANCE Elucidating zinc homeostasis is necessary for understanding both host-pathogen interactions and the performance of free-living bacteria in their natural environments. Escherichia coli acquires zinc under conditions of low zinc concentrations via the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other bacteria. In contrast, the heavy-metal-resistant bacterium C. metallidurans achieves high tolerance to zinc through sophisticated zinc handling and efflux systems operating on periplasmic zinc ions, so that removal of surplus zinc is a periplasmic feature in this bacterium. It is shown here that this process is augmented by the management of zinc by cytoplasmic zinc chaperones, whose synthesis is controlled by the Zur regulator. This demonstrates a new mechanism, involving compartmentalization, for organizing zinc homeostasis. PMID:28808127

Hair Zinc: an Index for Zinc Status in Under-Five Children from Low-Income Communities in Kanam Area of North-Central Nigeria.

PubMed

Jaryum, Kiri H; Okoye, Zebulon Sunday C; Stoecker, Barbara

2018-06-01

Nutritional deficiencies of trace elements are among the top ten causes of death in Sub Saharan Africa. In Kanam Local Government Area of Nigeria, the problem is compounded by high levels of poverty and illiteracy. Abnormally low hair zinc levels are important, sensitive diagnostic biochemical indices of Zinc deficiency. The purpose of this study is to assess the zinc status of children less than 5 years in Kanam local government area, north-central Nigeria, by measuring the zinc level in hair samples collected from 44 under-5 children across the area. A household survey was made to assess the pattern and frequency of consumption of zinc-rich foods which was done by means of questionnaire. Hair samples were analysed for zinc content by the inductively coupled plasma-mass spectrophotometry (ICP-MS). The data were analysed statistically using the Student's t test, z test, and Pearson correlation, while questionnaire-captured data were analysed by simple arithmetic. The results of the analyses showed that the average hair zinc level was 74.35 ± 48.05 μg/g. This was below the normal range of 130-140 μg/g, for children less than 5 years. Based on the results, 86.36% have hair zinc level below the lower limit of the normal range of 130 μg/g. Between the gender, boys have higher hair zinc content than girls. Data from the questionnaire showed that 53.45% of the population studied have poor/inadequate intake of zinc-rich foods of animal origin, a dietary behaviour reported to predispose to micronutrient deficiency, including zinc.

Swimming speed alteration of Artemia sp. and Brachionus plicatilis as a sub-lethal behavioural end-point for ecotoxicological surveys.

PubMed

Garaventa, Francesca; Gambardella, Chiara; Di Fino, Alessio; Pittore, Massimiliano; Faimali, Marco

2010-03-01

In this study, we investigated the possibility to improve a new behavioural bioassay (Swimming Speed Alteration test-SSA test) using larvae of marine cyst-forming organisms: e.g. the brine shrimp Artemia sp. and the rotifer Brachionus plicatilis. Swimming speed was investigated as a behavioural end-point for application in ecotoxicology studies. A first experiment to analyse the linear swimming speed of the two organisms was performed to verify the applicability of the video-camera tracking system, here referred to as Swimming Behavioural Recorder (SBR). A second experiment was performed, exposing organisms to different toxic compounds (zinc pyrithione, Macrotrol MT-200, and Eserine). Swimming speed alteration was analyzed together with mortality. The results of the first experiment indicate that SBR is a suitable tool to detect linear swimming speed of the two organisms, since the values have been obtained in accordance with other studies using the same organisms (3.05 mm s(-1) for Artemia sp. and 0.62 mm s(-1) for B. plicatilis). Toxicity test results clearly indicate that swimming speed of Artemia sp. and B. plicatilis is a valid behavioural end-point to detect stress at sub-lethal toxic substance concentrations. Indeed, alterations in swimming speed have been detected at toxic compound concentrations as low as less then 0.1-5% of their LC(50) values. In conclusion, the SSA test with B. plicatilis and Artemia sp. can be a good behavioural integrated output for application in marine ecotoxicology and environmental monitoring programs.

[Analysis and separation of organic and inorganic speciations of soluble zinc in edible flowers].

PubMed

Peng, Shan-shan; Huang, Guo-qing

2005-02-01

Considering the medicinal effects of the edible flowers, the authors studied the separation of trace element zinc's soluble organic and inorganic speciations in water decoction of three edible flowers: Chrysanthemum, Cottonrose hibiscus and Honeysucker by using the 0.45 microm membrane filter and amberlite XAD-2 macroreticular resins. And trace element zinc contents were determined by atomic absorption spectrometry. The optimal conditions for separation had been established. This study verifies the economic value of developing edible flowers, and provides theoretical basis for developing edible flowers as the third functional food materials.

New separators for nickel-zinc batteries

NASA Technical Reports Server (NTRS)

Sheibley, D. W.

1976-01-01

Flexible separators consisting of a substrate coated with a mixture of a polymer and organic and inorganic additives were cycle tested in nickel-zinc cells. By substituting a rubber-based resin for polyphenylene oxide in the standard inorganic-organic separator, major improvements in both cell life and flexibility were made. Substituting newsprint for asbestos as the substrate shows promise for use on the zinc electrode and reduces separator cost. The importance of ample electrolyte in the cells was noted. Cycle lives and the characteristics of these flexible, low-cost separators were compared with those of a standard microporous polypropylene separator.

Trace element, semivolatile organic, and chlorinated organic compound concentrations in bed sediments of selected streams at Fort Gordon, Georgia, February-April 2010

USGS Publications Warehouse

Thomas, Lashun K.; Journey, Celeste A.; Stringfield, Whitney J.; Clark, Jimmy M.; Bradley, Paul M.; Wellborn, John B.; Ratliff, Hagan; Abrahamsen, Thomas A.

2011-01-01

A spatial survey of streams was conducted from February to April 2010 to assess the concentrations of major ions, selected trace elements, semivolatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls associated with the bed sediments of surface waters at Fort Gordon military installation near Augusta, Georgia. This investigation expanded a previous study conducted in May 1998 by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, that evaluated the streambed sediment quality of selected surface waters at Fort Gordon. The data presented in this report are intended to help evaluate bed sediment quality in relation to guidelines for the protection of aquatic life, and identify temporal trends in trace elements and semivolatile organic compound concentrations at streambed sites previously sampled. Concentrations of 34 major ions and trace elements and 102 semivolatile organic, organochlorine pesticide, and polychlorinated biphenyl compounds were determined in the fine-grained fraction of bed sediment samples collected from 13 of the original 29 sites in the previous study, and 22 additional sites at Fort Gordon. Three of the sites were considered reference sites as they were presumed to be located away from potential sources of contaminants and were selected to represent surface waters flowing onto the fort, and the remaining 32 nonreference sites were presumed to be located within the contamination area at the fort. Temporal trends in trace elements and semivolatile organic compound concentrations also were evaluated at 13 of the 32 nonreference sites to provide an assessment of the variability in the number of detections and concentrations of constituents in bed sediment associated with potential sources, accumulation, and attenuation processes. Major ion and trace element concentrations in fine-grained bed sediment samples from most nonreference sites exceeded concentrations in samples from reference sites at Fort Gordon. Bed sediments from one of the nonreference sites sampled contained the highest concentrations of copper and lead with elevated levels of zinc and chromium relative to reference sites. The percentage change of major ions, trace elements, and total organic carbon that had been detected at sites previously sampled in May 1998 and current bed sediment sites ranged from -4 to 8 percent with an average percentage change of less than 1 percent. Concentrations of major ions and trace elements in bed sediments exceeded probable effect levels for aquatic life (based on the amphipod Hyalella azteca) established by the U.S. Environmental Protection Agency at 46 and 69 percent of the current and previously sampled locations, respectively. The greatest frequency of exceedances for major ions and trace elements in bed sediments was observed for lead. Concentrations of semivolatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls were detected in bed sediment samples at 94 percent of the sites currently sampled. Detections of these organic compounds were reported with greater frequency in bed sediments at upstream sampling locations, when compared to downstream locations. The greatest number of detections of these compounds was reported for bed sediment samples collected from two creeks above a lake. The percentage change of semivolatile organic compounds detected at previously sampled and current bed sediment sites ranged from -68 to 100 percent with the greatest percentage increase reported for one of the creeks above the lake. Concentrations of semivolatile organic compounds and polychlorinated biphenyls in bed sediments exceeded aquatic life criteria established by the U.S. Environmental Protection Agency at three sites. Contaminant compounds exceeding aquatic life criteria included fluoranthene, phenanthrene, anthracene, benzo(a)anthracene

Phenoxo bridged dinuclear Zn(II) Schiff base complex as new precursor for preparation zinc oxide nanoparticles: Synthesis, characterization, crystal structures and photoluminescence studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saeednia, S., E-mail: sami_saeednia@yahoo.com; Iranmanesh, P.; Ardakani, M. Hatefi

Highlights: • A novel nano-scale Zn(II) complex was synthesized by solvothermal method. • Chemical structure of the nanostructures was characterized as well as bulk complex. • The photoluminescence property of the complex was investigated at room temperature. • The thermogravimetry and differential thermal analysis were carried out. • Thermal decomposition of the nanostructures was prepared zinc oxide nanoparticles. - Abstract: Nanoparticles of a novel Zn(II) Schiff base complex, [Zn(HL)NO{sub 3}]{sub 2} (1), (H{sub 2}L = 2-[(2-hydroxy-propylimino) methyl] phenol), was synthesized by using solvothermal method. Shape, morphology and chemical structure of the synthesized nanoparticles were characterized by scanning electron microscopy (SEM),more » X-ray powder diffraction (XRD), Fourier Transform Infrared Spectoscopy (FT-IR) and UV–vis spectroscopy. Structural determination of compound 1 was determined by single-crystal X-ray diffraction. The results were revealed that the zinc complex is a centrosymmetric dimer in which deprotonated phenolates bridge the two five-coordinate metal atoms and link the two halves of the dimer. The thermal stability of compound 1 was analyzed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of the initial substrates concentration and reaction time on size and morphology of compound 1 nanostructure was investigated as well. Furthermore, the luminescent properties of the complex 1 were examined. ZnO nanoparticles with diameter between 15 and 20 nm were simply synthesized by solid-state transformation of compound 1 at 700 °C.« less

Stereoselective HDAC inhibition from cysteine-derived zinc-binding groups.

PubMed

Butler, Kyle V; He, Rong; McLaughlin, Kathryn; Vistoli, Giulio; Langley, Brett; Kozikowski, Alan P

2009-08-01

A series of small-molecule histone deacetylase (HDAC) inhibitors, which feature zinc binding groups derived from cysteine, were synthesized. These inhibitors were tested against multiple HDAC isoforms, and the most potent, compound 10, was determined to have IC(50) values below 1 microM. The compounds were also tested in a cellular assay of oxidative stress-induced neurodegeneration. Many of the inhibitors gave near-complete protection against cell death at 10 microM without the neurotoxicity seen with hydroxamic acid-based inhibitors, and were far more neuroprotective than HDAC inhibitors currently in clinical trials. Both enantiomers of cysteine were used in the synthesis of a variety of novel zinc-binding groups (ZBGs). Derivatives of L-cysteine were active in the HDAC inhibition assays, while the derivatives of D-cysteine were inactive. Notably, the finding that both the D- and L-cysteine derivatives were active in the neuroprotection assays suggests that multiple mechanisms are working to protect the neurons from cell death. Molecular modeling was employed to investigate the differences in inhibitory activity between the HDAC inhibitors generated from the two enantiomeric forms of cysteine.

Single and combined effects of organic selenium and zinc on egg fertility, hatchability, and embryonic mortality of exotic cochin hens

USDA-ARS?s Scientific Manuscript database

A study was conducted to examine the effects of three diets supplemented with organic selenium (Se) and zinc (Zn) on the performance of Cochin exotic breeder hens. Cochin hens (n=120) and males (n=12) at 42 wks of age were separated into four treatment groups with three replications per treatment. ...

Enhanced antibacterial activity and biocompatibility of zinc-incorporated organic-inorganic nanocomposite coatings via electrophoretic deposition.

PubMed

Huang, Pin; Ma, Kena; Cai, Xinjie; Huang, Dan; Yang, Xu; Ran, Jiabing; Wang, Fushi; Jiang, Tao

2017-12-01

Increased use of reconstruction procedures in orthopedics has improved the life of patients undergoing surgery. However, surgical site infection remains a major challenge. Efforts were made to fabricate antibacterial surfaces with good biocompatibility. This present study aimed to fabricate zinc-incorporated chitosan/gelatin (CS/G) nanocomposite coatings on the titanium substrates via electrophoretic deposition (EPD). Physicochemical characterization confirmed that zinc was successfully deposited in a metallic oxide/salt complex status. Transmission electron microscopic (TEM) results observed formation of core-shell nanosized particles released from the coatings. The selected-area electron diffraction (SAED) pattern of the particles presented faces of ZnO with organic background. Mechanical tests showed improved tensile and shear bond strength between substrates and zinc-incorporated coating surfaces. Zinc-incorporated CS/G coatings presented antibacterial abilities against both Gram-negative E. coli and Gram-positive S. aureus in a concentration-dependent manner. The generation of ZnO/Zn 2+ complex in the coatings may contribute to bacteria inhibition. In vitro study demonstrated that appropriate concentration of zinc could promote proliferative and osteogenic activities of rat bone marrow stromal cells. The present study suggested that zinc-incorporated CS/G coating was a promising candidate for surface modification of biomedical materials. Copyright © 2017 Elsevier B.V. All rights reserved.

An EXAFS study of zinc coordination in microbial cells.

PubMed

Webb, S M; Gaillard, J F; Jackson, B E; Stahl, D A

2001-03-01

Five microbes were isolated from metal amended enrichment cultures derived from the sediments of a lake contaminated by a zinc smelter. Each of these organisms was grown in pure culture in the presence of zinc. Quick Extended X-ray Absorption Fine Structure (QEXAFS) spectroscopy was used to investigate the average coordination environment of the zinc associated with the microbial biomass. Fitting of the first coordination shell of zinc shows that significant differences exist for each microbial species examined. The coordination environment of zinc varies between sulfurs to six-fold nitrogen/oxygen. with two microbial strains showing mixed coordination shells. Further study is required in order to characterize these sites and their locations within the cell.

[Zinc and chronic enteropathies].

PubMed

Giorgi, P L; Catassi, C; Guerrieri, A

1984-01-01

In recent years the nutritional importance of zinc has been well established; its deficiency and its symptoms have also been recognized in humans. Furthermore, Acrodermatitis Enteropathica has been isolated, a rare but severe disease, of which skin lesions, chronic diarrhoea and recurring infections are the main symptoms. The disease is related to the malfunctioning of intestinal absorption of zinc and can be treated by administering pharmacological doses of zinc orally. Good dietary sources of zinc are meat, fish and, to a less extent, human milk. The amount of zinc absorbed in the small intestine is influenced by other nutrients: some compounds inhibit this process (dietary fiber, phytate) while others (picolinic acid, citric acid), referred to as Zn-binding ligands (ZnBL) facilitate it. Citric acid is thought to be the ligand which accounts for the high level of bioavailability of zinc in human milk. zinc absorption occurs throughout the small intestine, not only in the prossimal tract (duodenum and jejunum) but also in the distal tract (ileum). Diarrhoea is one of the clinical manifestations of zinc deficiency, thus many illnesses distinguished by chronic diarrhoea entail a bad absorption of zinc. In fact, in some cases of chronic enteropathies in infants, like coeliac disease and seldom cystic fibrosis, a deficiency of zinc has been isolated. Some of the symptoms of Crohn's disease, like retarded growth and hypogonadism, have been related to hypozinchemia which is present in this illness. Finally, it is possible that some of the dietary treatments frequently used for persistent post-enteritis diarrhoea (i.e. cow's milk exclusion, abuse and misuse of dietary fiber like carrot and carub powder, use of soy formula) can constitute a scarce supply of zinc and therefore could promote the persistency of diarrhoea itself.

Comparisons of the spectroscopic and microbiological activities among coumarin-3-carboxylate, o-phenanthroline and zinc(II) complexes

NASA Astrophysics Data System (ADS)

Islas, María S.; Martínez Medina, Juan J.; Piro, Oscar E.; Echeverría, Gustavo A.; Ferrer, Evelina G.; Williams, Patricia A. M.

2018-06-01

Coumarins (2H-chromen-2-one) are oxygen-containing heterocyclic compounds that belong to the benzopyranones family. In this work we have synthesized different coordination complexes with coumarin-3-carboxylic acid (HCCA), o-phenanthroline (phen) and zinc(II). In the reported [Zn(CCA)2(H2O)2] complex, coumarin-3-carboxylate (CCA) is acting as a bidentate ligand while in the two prepared complexes, [Zn(phen)3]CCA(NO3) (obtained as a single crystal) and [Zn(CCA)2phen].4H2O, CCA is acting as a counterion of the complex cation [Zn(phen)3]+2 or coordinated to the metal center along with phen, respectively. These compounds were characterized on the basis of elemental analysis and thermogravimetry. NMR, FTIR and Raman spectroscopies of the compounds and the CCA potassium salt (KCCA) allow to determine several similarities and differences among them. Finally, their behavior against alkaline phosphatase enzyme and their antimicrobial activities were also measured.

Design, synthesis and anti-tumor activity study of novel histone deacetylase inhibitors containing isatin-based caps and o-phenylenediamine-based zinc binding groups.

PubMed

Gao, Shuai; Zang, Jie; Gao, Qianwen; Liang, Xuewu; Ding, Qinge; Li, Xiaoyang; Xu, Wenfang; Chou, C James; Zhang, Yingjie

2017-06-15

As a hot topic of epigenetic studies, histone deacetylases (HDACs) are related to lots of diseases, especially cancer. Further researches indicated that different HDAC isoforms played various roles in a wide range of tumor types. Herein a novel series of HDAC inhibitors with isatin-based caps and o-phenylenediamine-based zinc binding groups have been designed and synthesized through scaffold hopping strategy. Among these compounds, the most potent compound 9n exhibited similar if not better HDAC inhibition and antiproliferative activities against multiple tumor cell lines compared with the positive control entinostat (MS-275). Additionally, compared with MS-275 (IC 50 values for HDAC1, 2 and 3 were 0.163, 0.396 and 0.605µM, respectively), compound 9n with IC 50 values of 0.032, 0.256 and 0.311µM for HDAC1, 2 and 3 respectively, showed a moderate HDAC1 selectivity. Copyright © 2017. Published by Elsevier Ltd.

Relation of Land Use to Streamflow and Water Quality at Selected Sites in the City of Charlotte and Mecklenburg County, North Carolina, 1993-98

USGS Publications Warehouse

Bales, Jerad D.; Weaver, J. Curtis; Robinson, Jerald B.

1999-01-01

Streamflow and water-quality data were collected at nine sites in the city of Charlotte and Mecklenburg County, North Carolina, during 1993–97. Six of the basins drained areas having relatively homogeneous land use and were less than 0.3 square mile in size; the other three basins had mixed land use. Atmospheric wet-deposition data were collected in three of the basins during 1997–98.Streamflow yield varied by a factor of six among the sites, despite the fact that sites were in close proximity to one another. The lowest yield occurred in a residential basin having no curbs and gutters. The variability in mean flow from these small, relatively homogeneous basins is much greater than is found in streams draining basins that are 10 square miles in size or larger. The ratio of runoff to rainfall in the developing basin appears to have increased during the study period.Low-flow suspended-sediment concentrations in the study basins were about the same magnitude as median stormflow concentrations in Piedmont agricultural basins. Sediment concentrations were higher in the mixed land-use basins and in the developing basin. Median suspended-sediment concentrations in these basins generally were an order of magnitude greater than median concentrations in the other five basins, which had stable land use.Some of the highest total nitrogen concentrations occurred in residential basins. Total nitrogen concentrations detected in this study were about twice as high as concentrations in small Piedmont streams affected by agriculture and urbanization. Most of the total nitrogen consisted of organic nitrogen at all of the sites except in two residential land- use basins. The high ammonia content of lawn fertilizer may explain the higher ammonia concentration in stormflow from residential basins.The two basins with the highest median suspended-sediment concentrations also had the highest total phosphorus concentrations. Median total phosphorus concentrations measured in this study were several times greater than median concentrations in small Piedmont streams but almost an order of magnitude less than total phosphorus concentrations in Charlotte streams during the late 1970's.Bacteria concentrations are not correlated to streamflow. The highest bacteria levels were found in 'first-flush' samples. Higher fecal coliform concentrations were associated with residential land use.Chromium, copper, lead, and zinc occurred at all sites in concentrations that exceeded the North Carolina ambient water-quality standards. The median chromium concentration in the developing basin was more than double the median concentration at any other site. As with chromium, the maximum copper concentration in the developing basin was almost an order of magnitude greater than maximum concentrations at other sites. The highest zinc concentration also occurred in the developing basin. Samples were analyzed for 121 organic compounds and 57 volatile organic compounds. Forty-five organic compounds and seven volatile organic compounds were detected. At least five compounds were detected at all sites, and 15 or more compounds were detected at all sites except two mixed land-use basins. Atrazine, carbaryl, and metolachlor were detected at eight sites, and 90 percent of all samples had measurable amounts of atrazine. About 60 percent of the samples had detectable levels of carbaryl and metolachlor. Diazinon and malathion were measured in samples from seven sites, and methyl parathion, chlorpyrifos, alachlor, and 2,4-D were detected at four or more sites. The fewest compounds were detected in the larger, mixed land-use basins. Residential basins and the developing basin had the greatest number of detections of organic compounds.The pH of wet atmospheric deposition in three Charlotte basins was more variable than the pH measured at a National Atmospheric Deposition Program (NADP)site in Rowan County. Summer pH values were significantly lower than pH measured during the remainder of the year, probably as a result of poorer air quality and different weather patterns during the summer.Concentrations of ammonia and nitrate at the Charlotte sites generally were lower than those measured at the NADP site. Summer concentrations of ammonia and nitrate at both the Charlotte and the NADP sites were significantly greater than concentrations measured during the remainder of the year, again probably reflecting poorer summertime air-quality conditions.Sediment yields at the nine sites ranged from 77 tons per square mile per year in a residential basin to 4,700 tons per square mile per year at the developing basin. Residential areas that have been built-out for several years and industrial areas appear, in general, to have the lowest sediment yields for the Charlotte study sites.Average annual yields of total nitrogen loads ranged from about 1.7 tons per square mile to 6.6 tons per square mile. Average annual total phosphorus yields for all sites except the developing basin were less than 1.4 tons per square mile. Phosphorus yield at the developing basin was 13 .4 tons per square mile per year.Biochemical oxygen demand loading in 1993 from all of the permitted wastewater-treatment facilities in Charlotte and Mecklenburg County was about 1.5 tons per day or 548 tons per year. Converting this point-source loading to an annual yield for the 528 square-mile area of Mecklenburg County is equivalent to 1.03 tons per square mile per year, or a yield much lower than any of the yields measured at the nine study sites. In other words, biochemical oxygen demand loading from nonpoint sources in Mecklenburg County probably exceeds loading from all point sources by a large amount.Loads and average annual yields were computed for five metals-chromium, copper, lead, nickel, and zinc. The highest annual average yields for all five of these metals were in the developing basin, which also had the highest annual average suspended-sediment yield of all the sites. Estimated wet-deposition watershed loadings suggest that atmospheric deposition may be an important source of some metals, including chromium, copper, lead, and zinc, in Charlotte storm water.Storm water from residential land-use basins has higher concentrations of total nitrogen, fecal coliform bacteria, and organic compounds than do other land-use types. Reductions in suspended-sediment concentrations should generally result in reduced export of phosphorus and metals. Stable land uses, such as industrial areas and built-out residential basins, have lower sediment concentrations in stormwater than do mixed land use and developing basins. Finally, atmospheric deposition may be an important source of nitrogen and some metals in Charlotte stormwater.

Zinc poisoning

MedlinePlus

... including: Compounds used to make paint, rubber, dyes, wood preservatives, and ointments Rust prevention coatings Vitamin and ... a full recovery. If the poisoning is severe, death may occur up to a week after swallowing ...

Auger spectroscopy analysis of lubrication with zinc dialkyldithiophosphate of several metal combinations in sliding contact

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1979-01-01

Sliding friction experiments were conducted with aluminum and other riders rubbing on disks of various elemental metals in the presence of a thin film of zinc dialkyldithiophosphate (ZDP). Auger emission spectroscopy was used to in situ monitor the changes in surface chemistry with rubbing under various loads. The metal disks examined included iron, titanium, rhodium, tungsten, molybdenum, and copper. For equivalent films of ZDP the film is a more effective lubricant for some metals than it is for others. The important active element in the compound varies with the metal lubricated and is a function of metal chemistry. The zinc in the ZDP is susceptible to electron beam induced desorption.

Encapsulation of Antifouling Organic Biocides in Poly(lactic acid) Nanoparticles

PubMed Central

Kamtsikakis, Aristotelis; Kavetsou, Eleni; Chronaki, Konstantina; Kiosidou, Evangelia; Pavlatou, Evangelia; Karana, Alexandra; Papaspyrides, Constantine; Detsi, Anastasia; Karantonis, Antonis; Vouyiouka, Stamatina

2017-01-01

The scope of the current research was to assess the feasibility of encapsulating three commercial antifouling compounds, Irgarol 1051, Econea and Zinc pyrithione, in biodegradable poly(lactic acid) (PLA) nanoparticles. The emulsification–solvent evaporation technique was herein utilized to manufacture nanoparticles with a biocide:polymer ratio of 40%. The loaded nanoparticles were analyzed for their size and size distribution, zeta potential, encapsulation efficiency and thermal properties, while the relevant physicochemical characteristics were correlated to biocide–polymer system. In addition, the encapsulation process was scaled up and the prepared nanoparticles were dispersed in a water-based antifouling paint in order to examine the viability of incorporating nanoparticles in such coatings. Metallic specimens were coated with the nanoparticles-containing paint and examined regarding surface morphology. PMID:28952560

Encapsulation of Antifouling Organic Biocides in Poly(lactic acid) Nanoparticles.

PubMed

Kamtsikakis, Aristotelis; Kavetsou, Eleni; Chronaki, Konstantina; Kiosidou, Evangelia; Pavlatou, Evangelia; Karana, Alexandra; Papaspyrides, Constantine; Detsi, Anastasia; Karantonis, Antonis; Vouyiouka, Stamatina

2017-09-26

The scope of the current research was to assess the feasibility of encapsulating three commercial antifouling compounds, Irgarol 1051, Econea and Zinc pyrithione, in biodegradable poly(lactic acid) (PLA) nanoparticles. The emulsification-solvent evaporation technique was herein utilized to manufacture nanoparticles with a biocide:polymer ratio of 40%. The loaded nanoparticles were analyzed for their size and size distribution, zeta potential, encapsulation efficiency and thermal properties, while the relevant physicochemical characteristics were correlated to biocide-polymer system. In addition, the encapsulation process was scaled up and the prepared nanoparticles were dispersed in a water-based antifouling paint in order to examine the viability of incorporating nanoparticles in such coatings. Metallic specimens were coated with the nanoparticles-containing paint and examined regarding surface morphology.

Control of indium tin oxide anode work function modified using Langmuir-Blodgett monolayer for high-efficiency organic photovoltaics

NASA Astrophysics Data System (ADS)

Yokokura, Yuya; Dogase, Tomomichi; Shinbo, Tatsuki; Nakayashiki, Yuya; Takagi, Yusuke; Ueda, Kazuyoshi; Sarangerel, Khayankhyarvaa; Delgertsetseg, Byambasuren; Ganzorig, Chimed; Sakomura, Masaru

2017-08-01

The use of Langmuir-Blodgett (LB) monolayers to modify the indium tin oxide (ITO) work function and thus improve the performance of zinc phthalocyanine (ZnPc)/fullerene (C60)-based and boron subphthalocyanine chloride (SubPc)/C60-based small molecule organic photovoltaic devices (OPVs) was examined. In general, LB precursor compounds contain one or more long alkyl chain substituents that can act as spacers to prevent electrical contact with adjoining electrode surfaces. As one example of such a compound, arachidic acid (CH3(CH2)18COOH) was inserted in the forms of one-layer, three-layer or five-layer LB films between the anode ITO layer and the p-type layer in ZnPc-C60-based OPVs to investigate the effects of the long alkyl chain group when it acts as an electrically insulating spacer. The short-circuit current density (Jsc) values of the OPVs with the three- and five-layer inserts (1.78 mA.cm-2 and 0.61 mA.cm-2, respectively) were reduced dramatically, whereas the Jsc value for the OPV with the single-layer insertion (2.88 mA.cm-2) was comparable to that of the OPV without any insert (3.14 mA.cm-2). The ITO work function was shifted positively by LB deposition of a surfactant compound, C9F19C2H4-O-C2H4-COOH (PFECA), which contained a fluorinated head group. This positive effect was maintained even after formation of an upper p-type organic layer. The Jsc and open-circuit voltage (Voc) of the SubPc-C60-based OPV with the LB-modified ITO layers were effectively enhanced. As a result, a 42% increase in device efficiency was achieved.

Preliminary study on zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction

NASA Astrophysics Data System (ADS)

Wen, Yue-Hua; Cheng, Jie; Ning, Shang-Qi; Yang, Yu-Sheng

A zinc-air battery using zinc regeneration electrolysis with propanol oxidation as a counter electrode reaction is reported in this paper. It possesses functions of both zincate reduction and electrochemical preparation, showing the potential for increasing the electronic energy utilization. Charge/discharge tests and scanning electron microscopy (SEM) micrographs reveal that when a nickel sheet plated with the high-H 2-overpotential metal, cadmium, was used as the negative substrate electrode, the dendritic formation and hydrogen evolution are suppressed effectively, and granular zinc deposits become larger but relatively dense with the increase of charge time. The performance of batteries is favorable even if the charge time is as long as 5 h at the current density of 20 mA cm -2. Better discharge performance is achieved using a 'cavity-opening' configuration for the discharge cell rather than a 'gas-introducing' configuration. The highest energy efficiency is up to 59.2%. That is, the energy consumed by organic electro-synthesis can be recovered by 59.2%. Cyclic voltammograms show that the sintered nickel electrode exhibits a good electro-catalysis activity for the propanol oxidation. The increase of propanol concentration conduces to an enhancement in the organic electro-synthesis efficiency. The organic electro-synthesis current efficiency of 82% can be obtained.

Heat-transport mechanisms in molecular building blocks of inorganic/organic hybrid superlattices

NASA Astrophysics Data System (ADS)

Giri, Ashutosh; Niemelä, Janne-Petteri; Tynell, Tommi; Gaskins, John T.; Donovan, Brian F.; Karppinen, Maarit; Hopkins, Patrick E.

2016-03-01

Nanomaterial interfaces and concomitant thermal resistances are generally considered as atomic-scale planes that scatter the fundamental energy carriers. Given that the nanoscale structural and chemical properties of solid interfaces can strongly influence this thermal boundary conductance, the ballistic and diffusive nature of phonon transport along with the corresponding phonon wavelengths can affect how energy is scattered and transmitted across an interfacial region between two materials. In hybrid composites composed of atomic layer building blocks of inorganic and organic constituents, the varying interaction between the phononic spectrum in the inorganic crystals and vibronic modes in the molecular films can provide a new avenue to manipulate the energy exchange between the fundamental vibrational energy carriers across interfaces. Here, we systematically study the heat transfer mechanisms in hybrid superlattices of atomic- and molecular-layer-grown zinc oxide and hydroquinone with varying thicknesses of the inorganic and organic layers in the superlattices. We demonstrate ballistic energy transfer of phonons in the zinc oxide that is limited by scattering at the zinc oxide/hydroquinone interface for superlattices with a single monolayer of hydroquinone separating the thicker inorganic layers. The concomitant thermal boundary conductance across the zinc oxide interfacial region approaches the maximal thermal boundary conductance of a zinc oxide phonon flux, indicative of the contribution of long wavelength vibrations across the aromatic molecular monolayers in transmitting energy across the interface. This transmission of energy across the molecular interface decreases considerably as the thickness of the organic layers are increased.

The role of arbuscular mycorrhiza on change of heavy metal speciation in rhizosphere of maize in wastewater irrigated agriculture soil.

PubMed

Huang, Yi; Tao, Shu; Chen, You-jian

2005-01-01

To understand the roles of mycorrhiza in metal speciation in the rhizosphere and the impact on increasing host plant tolerance against excessive heavy metals in soil, maize (Zea mays L.) inoculated with arbuscular mycorrhizal fungus (Glomus mosseae) was cultivated in heavy metal contaminated soil. Speciations of copper, zinc and lead in the soil were analyzed with the technique of sequential extraction. The results showed that, in comparison to the bolked soil, the exchangeable copper increased from 26% to 43% in non-infected and AM-infected rhizoshpere respectively; while other speciation (organic, carbonate and Fe-Mn oxide copper) remained constant and the organic bound zinc and lead also increased but the exchangeable zinc and lead were undetectable. The organic bound copper, zinc and lead were higher by 15%, 40% and 20%, respectively, in the rhizosphere of arbuscular mycorrhiza infected maize in comparison to the non-infected maize. The results might indicate that mycorrhiza could protect its host plants from the phytotoxicity of excessive copper, zinc and lead by changing the speciation from bio-available to the non-bio-available form. The fact that copper and zinc accumulation in the roots and shoots of mycorrhia infected plants were significantly lower than those in the non-infected plants might also suggest that mycorrhiza efficiently restricted excessive copper and zinc absorptions into the host plants. Compared to the non-infected seedlings, the lead content of infected seedlings was 60% higher in shoots. This might illustrate that mycorrhiza have a different mechanism for protecting its host from excessive lead phytotoxicity by chelating lead in the shoots.

Structural stability and electronic structure of transition metal compound: HfN

NASA Astrophysics Data System (ADS)

Sarwan, Madhu; Shukoor, V. Abdul; Singh, Sadhna

2018-05-01

The structural stability of transition metal nitride (HfN) has been investigated using density functional theory (DFT) with the help of Quantum-espresso codes. Our calculations confirm that the hafnium nitride (HfN) is stable in zinc-blende (B3) and rock-salt (B1) type structure. We have also reported the structural and electronic properties of HfN compound. These structural properties have been compared with experimental and theoretical data available on this compound.

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound.

PubMed

Abdul Latip, Ahmad Faiz; Hussein, Mohd Zobir; Stanslas, Johnson; Wong, Charng Choon; Adnan, Rohana

2013-01-01

Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems.

Zinc: health effects and research priorities for the 1990s.

PubMed Central

Walsh, C T; Sandstead, H H; Prasad, A S; Newberne, P M; Fraker, P J

1994-01-01

This review critically summarizes the literature on the spectrum of health effects of zinc status, ranging from symptoms of zinc deficiency to excess exposure. Studies on zinc intake are reviewed in relation to optimum requirements as a function of age and sex. Current knowledge on the biochemical properties of zinc which are critical to the essential role of this metal in biological systems is summarized. Dietary and physiological factors influencing the bioavailability and utilization of zinc are considered with special attention to interactions with iron and copper status. The effects of zinc deficiency and toxicity are reviewed with respect to specific organs, immunological and reproductive function, and genotoxicity and carcinogenicity. Finally, key questions are identified where research is needed, such as the risks to human health of altered environmental distribution of zinc, assessment of zinc status in humans, effects of zinc status in relation to other essential metals on immune function, reproduction, neurological function, and the cardiovascular system, and mechanistic studies to further elucidate the biological effects of zinc at the molecular level. PMID:7925188

On the origin of life in the Zinc world: 1. Photosynthesizing, porous edifices built of hydrothermally precipitated zinc sulfide as cradles of life on Earth

PubMed Central

2009-01-01

Background The complexity of the problem of the origin of life has spawned a large number of possible evolutionary scenarios. Their number, however, can be dramatically reduced by the simultaneous consideration of various bioenergetic, physical, and geological constraints. Results This work puts forward an evolutionary scenario that satisfies the known constraints by proposing that life on Earth emerged, powered by UV-rich solar radiation, at photosynthetically active porous edifices made of precipitated zinc sulfide (ZnS) similar to those found around modern deep-sea hydrothermal vents. Under the high pressure of the primeval, carbon dioxide-dominated atmosphere ZnS could precipitate at the surface of the first continents, within reach of solar light. It is suggested that the ZnS surfaces (1) used the solar radiation to drive carbon dioxide reduction, yielding the building blocks for the first biopolymers, (2) served as templates for the synthesis of longer biopolymers from simpler building blocks, and (3) prevented the first biopolymers from photo-dissociation, by absorbing from them the excess radiation. In addition, the UV light may have favoured the selective enrichment of photostable, RNA-like polymers. Falsification tests of this hypothesis are described in the accompanying article (A.Y. Mulkidjanian, M.Y. Galperin, Biology Direct 2009, 4:27). Conclusion The suggested "Zn world" scenario identifies the geological conditions under which photosynthesizing ZnS edifices of hydrothermal origin could emerge and persist on primordial Earth, includes a mechanism of the transient storage and utilization of solar light for the production of diverse organic compounds, and identifies the driving forces and selective factors that could have promoted the transition from the first simple, photostable polymers to more complex living organisms. Reviewers This paper was reviewed by Arcady Mushegian, Simon Silver (nominated by Arcady Mushegian), Antoine Danchin (nominated by Eugene Koonin) and Dieter Braun (nominated by Sergey Maslov). PMID:19703272

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindberg, Daniel, E-mail: daniel.lindberg@abo.fi; Molin, Camilla, E-mail: camilla.molin@abo.fi; Hupa, Mikko, E-mail: mikko.hupa@abo.fi

Highlights: • We review the thermal treatment methods for ashes and residues from WtE plants. • We review the results from extensive laboratory work on vitrification, melting and vaporization of ash. • We analyze the results from the extensive patent literature on thermal treatment. • We review industrial concepts for thermal treatment of ash. - Abstract: Thermal treatment methods of bottom ash, fly ash and various types of APC (air pollution control) residues from waste-to-energy plants can be used to obtain environmentally stable material. The thermal treatment processes are meant to reduce the leachability of harmful residue constituents, destroy toxicmore » organic compounds, reduce residue volume, and produce material suitable for utilization. Fly ash and APC residues often have high levels of soluble salts, particularly chlorides, metals such as cadmium, lead, copper and zinc, and trace levels of organic pollutants such as dioxins and furans. Different thermal treatment methods can be used to either decompose or stabilize harmful elements and compounds in the ash, or separate them from the ash to get a material that can be safely stored or used as products or raw materials. In the present paper, thermal treatment methods, such as sintering, vitrification, and melting have been reviewed. In addition to a review of the scientific literature, a survey has been made of the extensive patent literature in the field.« less

Characterization of the quality of water, bed sediment, and fish in Mittry Lake, Arizona, 2014–15

USGS Publications Warehouse

Hermosillo, Edyth; Coes, Alissa L.

2017-03-01

Water, bed-sediment, and fish sampling was conducted in Mittry Lake, Arizona, in 2014–15 to establish current water-quality conditions of the lake. The parameters of temperature, dissolved-oxygen concentration, specific conductance, and alkalinity were measured in the field. Water samples were collected and analyzed for dissolved major ions, dissolved trace elements, dissolved nutrients, dissolved organic carbon, dissolved pesticides, bacteria, and suspended-sediment concentrations. Bed-sediment and fish samples were analyzed for trace elements, halogenated compounds, total mercury, and methylmercury.U.S. Environmental Protection Agency secondary maximum contaminant levels in drinking water were exceeded for sulfate, chloride, and manganese in the water samples. Trace-element concentrations were relatively similar between the inlet, middle, and outlet locations. Concentrations for nutrients in all water samples were below the Arizona Department of Environmental Quality’s water-quality standards for aquatic and wildlife uses, and all bacteria levels were below the Arizona Department of Environmental Quality’s recommended recreational water-quality criteria. Three out of 81 pesticides were detected in the water samples.Trace-element concentrations in bed sediment were relatively consistent between the inlet, middle, and outlet locations. Lead, manganese, nickel, and zinc concentrations, however, decreased from the inlet to outlet locations. Concentrations for lead, nickel, and zinc in some bed-sediment samples exceeded consensus-based sediment-quality guidelines probable effect concentrations. Eleven out of 61 halogenated compounds were detected in bed sediment at the inlet location, whereas three were detected at the middle location, and five were detected at the outlet location. No methylmercury was detected in bed sediment. Total mercury was detected in bed sediment at concentrations below the consensus-based sediment-quality guidelines probable effect concentration.Sixteen trace elements were detected in at least one of the fish-tissue samples, and trace-element concentrations were relatively consistent between the three fish-tissue samples. Seven halogenated compounds were detected in at least one of the whole-body fish samples; four to five compounds were detected in each fish. One fish-tissue sample exceeded the U.S. Environmental Protection Agency human health consumption criteria for methylmercury.

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeGrado, Timothy R.; Kemp, Bradley J.; Pandey, Mukesh K.

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). 63Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. A dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of 63Zn-zinc citrate (~330 MBq). Subsequently, body PET images were acquired. Urine and venous blood were analyzed to give information on urinary excretion and pharmacokinetics. Regional cerebral 63Zn clearances were compared with 11C-Pittsburgh Compound B ( 11C-PiB) andmore » 18F-fluorodeoxyglucose ( 18F-FDG) imaging data. 63Zn-zinc citrate was well tolerated in human participants with no adverse events monitored. Tissues of highest uptake were liver, pancreas, and kidney, with moderate uptake being seen in intestines, prostate (in males), thyroid, spleen, stomach, pituitary, and salivary glands. Moderate brain uptake was observed, and regional dependencies were observed in 63Zn clearance kinetics in relationship with regions of high amyloid-β plaque burden ( 11C-PiB) and 18F-FDG hypometabolism. In conclusion, zinc transport was successfully imaged in human participants using the PET probe 63Zn-zinc citrate. Primary sites of uptake in the digestive system accent the role of zinc in gastrointestinal function. Preliminary information on zinc kinetics in patients with AD evidenced regional differences in clearance rates in correspondence with regional amyloid-β pathology, warranting further imaging studies of zinc homeostasis in patients with AD.« less

Thermodynamics Calculation and Experimental Study on Separation of Bismuth from a Bismuth Glance Concentrate Through a Low-Temperature Molten Salt Smelting Process

NASA Astrophysics Data System (ADS)

Yang, Jian-Guang; He, De-Wen; Tang, Chao-Bo; Chen, Yong-Ming; Sun, Ya-Hui; Tang, Mo-Tang

2011-08-01

The main purpose of this study is to characterize and separate bismuth from a bismuth glance concentrate through a low-temperature, sulfur-fixing smelting process. This article reports on a study conducted on the optimization of process parameters, such as Na2CO3 and zinc oxide wt pct in charging, smelting temperature, smelting duration on the bismuth yield, resultant crude bismuth grade, and sulfur-fixing rate. A maximum bismuth recovery of 97.31 pct, crude bismuth grade of 96.93 pct, and 98.23 pct sulfur-fixing rate are obtained when a charge (containing 63.50 wt pct of Na2CO3 and 22.50 wt pct of bismuth glance, as well as 5 pct in excess of the stoichiometric requirement of zinc oxide dosage) is smelted at 1000 K (727 °C) for 150 minutes. This smelting operation is free from atmospheric pollution because zinc oxide is used as the sulfur-fixing agent, which can capture sulfur from bismuth sulfide and form the more thermodynamic-stable compound, zinc sulfide. The solid residue is subjected to a mineral dressing operation to obtain suspension, which is filtered to produce a cake, representing the solid particles of zinc sulfide. Based on the results of the chemical content analysis of the as-resultant zinc sulfide, more than 93 pct zinc sulfide can be recovered, and the recovered zinc sulfide grade can reach 60.20 pct. This material can be sold as zinc sulfide concentrate or roasted to be regenerated as zinc oxide.

BIOCHEMISTRY OF MOBILE ZINC AND NITRIC OXIDE REVEALED BY FLUORESCENT SENSORS

PubMed Central

Pluth, Michael D.; Tomat, Elisa; Lippard, Stephen J.

2010-01-01

Biologically mobile zinc and nitric oxide (NO) are two prominent examples of inorganic compounds involved in numerous signaling pathways in living systems. In the past decade, a synergy of regulation, signaling, and translocation of these two species has emerged in several areas of human physiology, providing additional incentive for developing adequate detection systems for Zn(II) ions and NO in biological specimens. Fluorescent probes for both of these bioinorganic analytes provide excellent tools for their detection, with high spatial and temporal resolution. We review the most widely used fluorescent sensors for biological zinc and nitric oxide, together with promising new developments and unmet needs of contemporary Zn(II) and NO biological imaging. The interplay between zinc and nitric oxide in the nervous, cardiovascular, and immune systems is highlighted to illustrate the contributions of selective fluorescent probes to the study of these two important bioinorganic analytes. PMID:21675918

Calcium and zinc DTPA administration for internal contamination with plutonium-238 and americium-241.

PubMed

Kazzi, Ziad N; Heyl, Alexander; Ruprecht, Johann

2012-08-01

The accidental or intentional release of plutonium or americium can cause acute and long term adverse health effects if they enter the human body by ingestion, inhalation, or injection. These effects can be prevented by rapid removal of these radionuclides by chelators such as calcium or zinc diethylenetriaminepentaacetate (calcium or zinc DTPA). These compounds have been shown to be efficacious in enhancing the elimination of members of the actinide family particularly plutonium and americium when administered intravenously or by nebulizer. The efficacy and adverse effects profile depend on several factors that include the route of internalization of the actinide, the type, and route time of administration of the chelator, and whether the calcium or zinc salt of DTPA is used. Current and future research efforts should be directed at overcoming limitations associated with the use of these complex drugs by using innovative methods that can enhance their structural and therapeutic properties.

First PET Imaging Studies With 63Zn-Zinc Citrate in Healthy Human Participants and Patients With Alzheimer Disease.

PubMed

DeGrado, Timothy R; Kemp, Bradley J; Pandey, Mukesh K; Jiang, Huailei; Gunderson, Tina M; Linscheid, Logan R; Woodwick, Allison R; McConnell, Daniel M; Fletcher, Joel G; Johnson, Geoffrey B; Petersen, Ronald C; Knopman, David S; Lowe, Val J

2016-01-01

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). 63 Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. Dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of 63 Zn-zinc citrate (∼330 MBq). Subsequently, body PET images were acquired. Urine and venous blood were analyzed to give information on urinary excretion and pharmacokinetics. Regional cerebral 63 Zn clearances were compared with 11 C-Pittsburgh Compound B ( 11 C-PiB) and 18 F-fluorodeoxyglucose ( 18 F-FDG) imaging data. 63 Zn-zinc citrate was well tolerated in human participants with no adverse events monitored. Tissues of highest uptake were liver, pancreas, and kidney, with moderate uptake being seen in intestines, prostate (in males), thyroid, spleen, stomach, pituitary, and salivary glands. Moderate brain uptake was observed, and regional dependencies were observed in 63 Zn clearance kinetics in relationship with regions of high amyloid-β plaque burden ( 11 C-PiB) and 18 F-FDG hypometabolism. In conclusion, zinc transport was successfully imaged in human participants using the PET probe 63 Zn-zinc citrate. Primary sites of uptake in the digestive system accent the role of zinc in gastrointestinal function. Preliminary information on zinc kinetics in patients with AD evidenced regional differences in clearance rates in correspondence with regional amyloid-β pathology, warranting further imaging studies of zinc homeostasis in patients with AD. © The Author(s) 2016.

First PET Imaging Studies With 63 Zn-Zinc Citrate in Healthy Human Participants and Patients With Alzheimer Disease

DOE PAGES

DeGrado, Timothy R.; Kemp, Bradley J.; Pandey, Mukesh K.; ...

2016-01-01

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). 63Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. A dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of 63Zn-zinc citrate (~330 MBq). Subsequently, body PET images were acquired. Urine and venous blood were analyzed to give information on urinary excretion and pharmacokinetics. Regional cerebral 63Zn clearances were compared with 11C-Pittsburgh Compound B ( 11C-PiB) andmore » 18F-fluorodeoxyglucose ( 18F-FDG) imaging data. 63Zn-zinc citrate was well tolerated in human participants with no adverse events monitored. Tissues of highest uptake were liver, pancreas, and kidney, with moderate uptake being seen in intestines, prostate (in males), thyroid, spleen, stomach, pituitary, and salivary glands. Moderate brain uptake was observed, and regional dependencies were observed in 63Zn clearance kinetics in relationship with regions of high amyloid-β plaque burden ( 11C-PiB) and 18F-FDG hypometabolism. In conclusion, zinc transport was successfully imaged in human participants using the PET probe 63Zn-zinc citrate. Primary sites of uptake in the digestive system accent the role of zinc in gastrointestinal function. Preliminary information on zinc kinetics in patients with AD evidenced regional differences in clearance rates in correspondence with regional amyloid-β pathology, warranting further imaging studies of zinc homeostasis in patients with AD.« less

Undergraduates in the lab: Analyzing metal and organic contaminants in oysters and sediments from southeastern North Carolina

NASA Astrophysics Data System (ADS)

Mead, R. N.; Kipp, L. E.; Liberatore, H.; Sherard, S.; Steagall, M.; Skrabal, S. A.

2016-02-01

A state-funded project to analyze a suite of metal and organic contaminants in oyster tissues and ambient sediments was carried out nearly exclusively by over 10 undergraduates at the University of North Carolina Wilmington. This study will present Concentrations of various trace metals (most notably arsenic, copper, mercury, and zinc) and organic contaminants (polycyclic aromatic hydrocarbons and the antibacterial, triclosan) have been determined in oyster tissues and adjacent sediments in New Hanover and Brunswick counties, southeastern North Carolina. Trace metals that exceeded national median levels at multiple sites in this study included arsenic, copper, and zinc. Elevated levels of arsenic (exceeding the national median and, often, the national 85th percentiles) in oyster tissues are characteristic of much of the southeastern United States; these elevations are attributed to high natural background levels in the underlying bedrock and sediments as well as historical contamination by arsenic-containing agricultural pesticides. Another metal of national concern is mercury; however, concentrations of this metal were mostly at the national median for oyster tissue. Polycyclic aromatic hydrocarbons (PAHs) barely exceeded or were near the national median at only 3 sites, 2 in Lockwood Folly estuary, Brunswick County and 1 at Bradley Creek, New Hanover County. Concentrations at the remaining sites were 4 to >10 times less than the national median. Triclosan, an antibacterial compound used in many consumer products, was found in oyster tissues and sediments at the 4 sites at which it was examined. Oyster tissues contained triclosan at levels 2 to 43 times as high as adjacent sediments, indicating its bioaccumulation potential. Levels of metals and PAHs in oyster tissues are consistently elevated near more urbanized areas but are unlikely to be at levels harmful for human consumption.

Inhibitors of the serotonin transporter protein (SERT): the design and synthesis of biotinylated derivatives of 3-(1,2,3,6-tetrahydro-pyridin-4-yl)-1H-indoles. High-affinity serotonergic ligands for conjugation with quantum dots.

PubMed

Tomlinson, Ian D; Mason, John N; Blakely, Randy D; Rosenthal, Sandra J

2005-12-01

There is a growing demand for compounds with specificity for the serotonin transporter protein (SERT) that can be conjugated to cadmium selenide/zinc sulfide core shell nanocrystals. This letter describes the design and synthesis of two different biotinylated SERT antagonists that can be attached to streptavidin-coated cadmium selenide/zinc sulfide core shell nanocrystals.

Effect of doping with nickel ions on the structural state of a zinc oxide crystal

NASA Astrophysics Data System (ADS)

Dubinin, S. F.; Sokolov, V. I.; Parkhomenko, V. D.; Maksimov, V. I.; Gruzdev, N. B.

2009-10-01

The fine structure of a hexagonal zinc oxide crystal doped with nickel ions of the composition Zn1 - x Ni x O has been studied using neutron diffraction and magnetic measurements. It is established that even at very low doping levels ( x = 0.0004), the crystal undergoes local distortions in basal planes of the initial hexagonal lattice. The local distortions are assumed to be sources of the formation of ferromagnetism in compounds of this class.

Synthesis, biological evaluation, and molecular docking of Ugi products containing a zinc-chelating moiety as novel inhibitors of histone deacetylases.

PubMed

Grolla, Ambra A; Podestà, Valeria; Chini, Maria Giovanna; Di Micco, Simone; Vallario, Antonella; Genazzani, Armando A; Canonico, Pier Luigi; Bifulco, Giuseppe; Tron, Gian Cesare; Sorba, Giovanni; Pirali, Tracey

2009-05-14

HDAC inhibitors show great promise for the treatment of cancer. As part of a broader effort to explore the SAR of HDAC inhibitors, synthesis, biological evaluation, and molecular docking of novel Ugi products containing a zinc-chelating moiety are presented. One compound shows improved inhibitory potencies compared to SAHA, demonstrating that hindered lipophilic residues grafted on the peptide scaffold of the alpha-aminoacylamides can be favorable in the interaction with the enzyme.

Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

PubMed

Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

2014-09-01

Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular structure, vibrational spectra, NLO and MEP analysis of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II)

NASA Astrophysics Data System (ADS)

Tanak, Hasan; Toy, Mehmet

2013-11-01

The molecular geometry and vibrational frequencies of bis[2-hydroxy-кO-N-(2-pyridyl)-1-naphthaldiminato-кN]zinc(II) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-311G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The energetic and atomic charge behavior of the title compound in solvent media has been examined by applying the Onsager and the polarizable continuum model. To investigate second order nonlinear optical properties of the title compound, the electric dipole (μ), linear polarizability (α) and first-order hyperpolarizability (β) were computed using the density functional B3LYP and CAM-B3LYP methods with the 6-31+G(d) basis set. According to our calculations, the title compound exhibits nonzero (β) value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), frontier molecular orbitals, and thermodynamic properties were performed at B3LYP/6-311G(d,p) level of theory.

Two dimensional self-assembly zinc porphyrin and zinc phthalocyanine heterojunctions with record high power conversion efficiencies

NASA Astrophysics Data System (ADS)

Yu, Junting; Jiang, Zhou; Hao, Yifan; Zhu, Qianhong; Zhao, Mingliang; Jiang, Xue; Zhao, Jijun

2018-06-01

Compared to inorganic solar cells, the power conversion efficiencies (PCEs) of organic solar cells are much lower, but they are compensated by many merits such as lower cost, less weight, and tunable structures, making them prospective for further applications. Porphyrin and phthalocyanine are the two most significant materials for organic solar cells due to their strong light-absorbing properties and semiconductor characteristics. However, there is little research on the 2D heterojunction solar cells based on these two materials, meanwhile the PCEs of them are still low. Here we have self-assembled several 2D zinc porphyrins (ZnPors) and performed first-principles simulation to demonstrate their good stability, suitable light harvesting, and high charge carrier mobility. By perfectly matching lattice constants and molecular energy levels between those 2D ZnPors and our previous proposed zinc phthalocyanines (ZnPcs), 11 type-II organic heterojunctions are constructed to further improve their charge separation capability. Those advantages endow 2D ZnPors and ZnPcs appreciable PCEs for solar cells. Among them, the theoretical PCE of 2D ZnPors/ZnPcs heterojunctions achieves as high as 19.84%, which exceeds all reported organic solar cells, and even approaches the PCEs of inorganic solar cells. These results indicate that our 2D ZnPors and 2D ZnPcs are good candidate materials for future organic solar cells.

Recent advances in knowledge of zinc nutrition and human health.

PubMed

Hess, Sonja Y; Lönnerdal, Bo; Hotz, Christine; Rivera, Juan A; Brown, Kenneth H

2009-03-01

Zinc deficiency increases the risk and severity of a variety of infections, restricts physical growth, and affects specific outcomes of pregnancy. Global recognition of the importance of zinc nutrition in public health has expanded dramatically in recent years, and more experience has accumulated on the design and implementation of zinc intervention programs. Therefore, the Steering Committee of the International Zinc Nutrition Consultative Group (IZiNCG) completed a second IZiNCG technical document that reexamines the latest information on the intervention strategies that have been developed to enhance zinc nutrition and control zinc deficiency. In particular, the document reviews the current evidence regarding preventive zinc supplementation and the role of zinc as adjunctive therapy for selected infections, zinc fortification, and dietary diversification or modification strategies, including the promotion and protection of breastfeeding and biofortification. The purposes of this introductory paper are to summarize new guidelines on the assessment of population zinc status, as recommended by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), the International Atomic Energy Agency (IAEA), and IZiNCG, and to provide an overview on several new advances in zinc metabolism. The following papers will then review the intervention strategies individually.

Zinc and its importance for human health: An integrative review

PubMed Central

Roohani, Nazanin; Hurrell, Richard; Kelishadi, Roya; Schulin, Rainer

2013-01-01

Since its first discovery in an Iranian male in 1961, zinc deficiency in humans is now known to be an important malnutrition problem world-wide. It is more prevalent in areas of high cereal and low animal food consumption. The diet may not necessarily be low in zinc, but its bio-availability plays a major role in its absorption. Phytic acid is the main known inhibitor of zinc. Compared to adults, infants, children, adolescents, pregnant, and lactating women have increased requirements for zinc and thus, are at increased risk of zinc depletion. Zinc deficiency during growth periods results in growth failure. Epidermal, gastrointestinal, central nervous, immune, skeletal, and reproductive systems are the organs most affected clinically by zinc deficiency. Clinical diagnosis of marginal Zn deficiency in humans remains problematic. So far, blood plasma/serum zinc concentration, dietary intake, and stunting prevalence are the best known indicators of zinc deficiency. Four main intervention strategies for combating zinc deficiency include dietary modification/diversification, supplementation, fortification, and bio-fortification. The choice of each method depends on the availability of resources, technical feasibility, target group, and social acceptance. In this paper, we provide a review on zinc biochemical and physiological functions, metabolism including, absorption, excretion, and homeostasis, zinc bio-availability (inhibitors and enhancers), human requirement, groups at high-risk, consequences and causes of zinc deficiency, evaluation of zinc status, and prevention strategies of zinc deficiency. PMID:23914218

Zinc hazards to plants and animals with emphasis on fishery and wildlife resources

USGS Publications Warehouse

Eisler, R.; Cheremisinoff, Paul N.

1997-01-01

Ecological and toxicological aspects of zinc in the environment are reviewed with emphasis on natural resources. Subtopics include sources and uses; chemical and biochemical properties; carcinogenicity, mutagenicity, teratogenicity; background concentrations in biological and nonbiological compartments; effects of zinc deficiency; toxic and sublethal effects on terrestrial plants and invertebrates, aquatic organisms, birds, and mammals; and recommendations for the protection of sensitive resources.

Supplemental levels of iron and calcium interfere with repletion of zinc status in zinc-deficient animals.

PubMed

Jayalakshmi, S; Platel, Kalpana

2016-05-18

Negative interactions between minerals interfering with each other's absorption are of concern when iron and calcium supplements are given to pregnant women and children. We have previously reported that supplemental levels of iron and calcium inhibit the bioaccessibility of zinc, and compromise zinc status in rats fed diets with high levels of these two minerals. The present study examined the effect of supplemental levels of iron and calcium on the recovery of zinc status during a zinc repletion period in rats rendered zinc-deficient. Iron and calcium, both individually and in combination, significantly interfered with the recovery of zinc status in zinc deficient rats during repletion with normal levels of zinc in the diet. Rats maintained on diets containing supplemental levels of these two minerals had significantly lower body weight, and the concentration of zinc in serum and organs was significantly lower than in zinc-deficient rats not receiving the supplements. Iron and calcium supplementation also significantly inhibited the activity of zinc-containing enzymes in the serum as well as liver. Both iron and calcium independently exerted this negative effect on zinc status, while their combination seemed to have a more prominent effect, especially on the activities of zinc containing enzymes. This investigation is probably the first systematic study on the effect of these two minerals on the zinc status of zinc deficient animals and their recovery during repletion with normal amounts of zinc.

Zinc Biochemistry: From a Single Zinc Enzyme to a Key Element of Life12

PubMed Central

Maret, Wolfgang

2013-01-01

The nutritional essentiality of zinc for the growth of living organisms had been recognized long before zinc biochemistry began with the discovery of zinc in carbonic anhydrase in 1939. Painstaking analytical work then demonstrated the presence of zinc as a catalytic and structural cofactor in a few hundred enzymes. In the 1980s, the field again gained momentum with the new principle of “zinc finger” proteins, in which zinc has structural functions in domains that interact with other biomolecules. Advances in structural biology and a rapid increase in the availability of gene/protein databases now made it possible to predict zinc-binding sites from metal-binding motifs detected in sequences. This procedure resulted in the definition of zinc proteomes and the remarkable estimate that the human genome encodes ∼3000 zinc proteins. More recent developments focus on the regulatory functions of zinc(II) ions in intra- and intercellular information transfer and have tantalizing implications for yet additional functions of zinc in signal transduction and cellular control. At least three dozen proteins homeostatically control the vesicular storage and subcellular distribution of zinc and the concentrations of zinc(II) ions. Novel principles emerge from quantitative investigations on how strongly zinc interacts with proteins and how it is buffered to control the remarkably low cellular and subcellular concentrations of free zinc(II) ions. It is fair to conclude that the impact of zinc for health and disease will be at least as far-reaching as that of iron. PMID:23319127

Assessment of Fish Habitat, Water Quality, and Selected Contaminants in Streambed Sediments in Noyes Slough, Fairbanks, Alaska, 2001-2002

USGS Publications Warehouse

Kennedy, Ben W.; Whitman, Matthew S.; Burrows, Robert L.; Richmond, Sharon A.

2004-01-01

During 2001-2002, the U.S. Geological Survey sampled streambed sediment at 23 sites, measured water quality at 26 sites, and assessed fish habitat for the entire length of Noyes Slough, a 5.5-mile slough of the Chena River in Fairbanks, Alaska. These studies were undertaken to document the environmental condition of the slough and to provide information to the public for consideration in plans to improve environmental conditions of the waterway. The availability of physical habitat for fish in the slough does not appear to be limited, although some beaver dams and shallow water may restrict movement, particularly during low flow. Elevated water temperatures in summer and low dissolved-oxygen concentrations are the principle factors adversely affecting water quality in Noyes Slough. Increased flow mitigated poor water-quality conditions and reduced the number of possible fish barriers. Flow appears to be the most prominent mechanism shaping water quality and fish habitat in Noyes Slough. Streambed sediment samples collected at 23 sites in 2001 were analyzed for 24 trace elements. Arsenic, lead, and zinc were the only trace elements detected in concentrations that exceed probable effect levels for the protection of aquatic life. The background concentration for arsenic in Noyes Slough is naturally elevated because of significant concentrations of arsenic in local bedrock and ground water. Sources of the zinc and lead contamination are uncertain, however both lead and zinc are common urban contaminants. Streambed-sediment samples from 12 sites in 2002 were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), and semivolatile organic compounds (SVOCs). The concentration of bis(2-ethylhexyl)phthalate of 2,600 micrograms per kilogram (?g/kg) for one sample from the site above Aurora Drive approached the aquatic-life criterion of 2,650 ?g/kg. Low concentrations of p-cresol, chrysene, and fluoranthene were detected in most of the sediment samples. The presence of these compounds in Noyes Slough sediment was expected because cresols are emitted to the atmosphere in the exhaust from motor vehicles and chrysene and fluoranthene are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances. Low-level concentrations of DDT or its degradation products DDD and DDE were detected in all samples collected during 2002. However, total DDT (DDT+DDD+DDE) concentrations are less than the effects range median aquatic-life criterion of 46.1 ?g/kg. In general, total DDT concentrations were less than 10 ?g/kg, except for samples from two sites that have estimated concentrations of about 14 and 20 ?g/kg.

Water-quality characteristics of selected public recreational lakes and ponds in Connecticut

USGS Publications Warehouse

Healy, D.F.; Kulp, K.P.

1995-01-01

Reconnaissance limnological and lakebed-sediment surveys were conducted in Connecticut during 1989-91 by the U.S. Geological Survey, in cooperation with the Connecticut Department of Environmental Protec- tion, to evaluate water-quality characteristics of selected public recreational lakes and ponds in the State. Limnological surveys were conducted on 49 lakes and ponds selected from a list of 105 publicly owned waterbodies that qualified for water- quality assessments under Section 314 of the Federal Clean Water Act. Lakebed-sediment surveys were conducted in 9 river impoundments and 1 riverine lake below industrial areas and 2 headwater lakes in relatively pristine areas. The limnological surveys consisted of two sampling events--during spring turnover and during the summer stratifi- cation. Each sampling event included depth profiles of water temperature, specific conductance, hydrogen-ion activity, and dissolved oxygen concen- trations; measurements of Secchi disc transparency; and the collection of samples for the analyses of alkalinity, chlorophyll, phosphorus, and nitrogen concentrations. Areal extent and population density of the dominant aquatic macrophytes were qualita- tively noted during the summer sampling event. These water-quality data were used to determine the trophic classification and acidification status of the 49 lakes. The trophic classification yielded the following results: 2 oligotrophic, 8 early mesotrophic, 13 mesotrophic, 5 late mesotrophic, 10 eutrophic, and 11 highly eutrophic lakes. In terms of acidification status, 7 lakes were classified as acid threatened and 42 as not threatened. A Wilcoxon two-tailed signed rank test was used to compare data for 13 lakes and ponds from the present survey with data from the 1973-75 or 1978-79 surveys conducted by the Connecticut Agricultural Experiment Station and Connecticut Department of Environmental Protection. The test showed no significant difference at the 90 percent confidence level for spring nitrogen and summer chlorophyll-a concen- trations, a significant increase at the 90 percent confidence level in summer phosphorus concentra- tions, and a significant decrease at the 95 percent confidence level in summer transparency. For the lakebed-sediment surveys, composite-grab samples were collected from the deepest part of each lake. Samples were analyzed for arsenic, cyanide, organic and inorganic carbon, selected metals, and methylene-extractable, synthetic organic compounds classified by the U.S. Environmental Protection Agency as semi-volatile priority pollutants. Hanover Pond, Eagleville Lake, and West Thompson Lake had three of the four highest concentrations of cadmium, chromium, copper, lead, nickel, zinc, and cyanide. The four lakes with the highest concentrations of arsenic (Aspinook Pond, Fitchville Pond, Mashapaug Pond, and West Thompson Lake) are located in the eastern part of Connecticut. The three samples with the highest mercury concentrations were from Lake Lillinonah and Lake Zoar. There appears to be a positive correlation between the concentrations of cadmium, chromium, copper, lead, nickel, zinc, and cyanide. Only 15 of the 54 synthetic organic compounds analyzed for were detected in 9 of the 12 lakes sampled. Of these 15 compounds, 14 are polycyclic aromatic hydrocarbons and the 15th is a phthalate ester. Hanover Pond had the most compounds detected (9), and phenanthrene was the compound detected in the most lakes (8).

Redox-Mediated Stabilization in Zinc Molybdenum Nitrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arca, Elisabetta; Lany, Stephan; Perkins, John D.

We report on the theoretical prediction and experimental realization of new ternary zinc molybdenum nitride compounds. We used theory to identify previously unknown ternary compounds in the Zn-Mo-N systems, Zn 3MoN 4 and ZnMoN 2, and to analyze their bonding environment. Experiments show that Zn-Mo-N alloys can form in broad composition range from Zn 3MoN 4 to ZnMoN 2 in the wurtzite-derived structure, accommodating very large off-stoichiometry. Interestingly, the measured wurtzite-derived structure of the alloys is metastable for the ZnMoN 2 stoichiometry, in contrast to the Zn 3MoN 4 stoichiometry, where ordered wurtzite is predicted to be the ground state.more » The formation of Zn 3MoN 4-ZnMoN 2 alloy with wurtzite-derived crystal structure is enabled by the concomitant ability of Mo to change oxidation state from +VI in Zn 3MoN 4 to +IV in ZnMoN 2, and the capability of Zn to contribute to the bonding states of both compounds, an effect that we define as 'redox-mediated stabilization.' The stabilization of Mo in both the +VI and +IV oxidation states is due to the intermediate electronegativity of Zn, which enables significant polar covalent bonding in both Zn 3MoN 4 and ZnMoN 2 compounds. The smooth change in the Mo oxidation state between Zn 3MoN 4 and ZnMoN 2 stoichiometries leads to a continuous change in optoelectronic properties - from resistive and semitransparent Zn 3MoN 4 to conductive and absorptive ZnMoN 2. The reported redox-mediated stabilization in zinc molybdenum nitrides suggests there might be many undiscovered ternary compounds with one metal having an intermediate electronegativity, enabling significant covalent bonding, and another metal capable of accommodating multiple oxidation states, enabling stoichiometric flexibility.« less

Redox-Mediated Stabilization in Zinc Molybdenum Nitrides

DOE PAGES

Arca, Elisabetta; Lany, Stephan; Perkins, John D.; ...

2018-03-01

We report on the theoretical prediction and experimental realization of new ternary zinc molybdenum nitride compounds. We used theory to identify previously unknown ternary compounds in the Zn-Mo-N systems, Zn 3MoN 4 and ZnMoN 2, and to analyze their bonding environment. Experiments show that Zn-Mo-N alloys can form in broad composition range from Zn 3MoN 4 to ZnMoN 2 in the wurtzite-derived structure, accommodating very large off-stoichiometry. Interestingly, the measured wurtzite-derived structure of the alloys is metastable for the ZnMoN 2 stoichiometry, in contrast to the Zn 3MoN 4 stoichiometry, where ordered wurtzite is predicted to be the ground state.more » The formation of Zn 3MoN 4-ZnMoN 2 alloy with wurtzite-derived crystal structure is enabled by the concomitant ability of Mo to change oxidation state from +VI in Zn 3MoN 4 to +IV in ZnMoN 2, and the capability of Zn to contribute to the bonding states of both compounds, an effect that we define as 'redox-mediated stabilization.' The stabilization of Mo in both the +VI and +IV oxidation states is due to the intermediate electronegativity of Zn, which enables significant polar covalent bonding in both Zn 3MoN 4 and ZnMoN 2 compounds. The smooth change in the Mo oxidation state between Zn 3MoN 4 and ZnMoN 2 stoichiometries leads to a continuous change in optoelectronic properties - from resistive and semitransparent Zn 3MoN 4 to conductive and absorptive ZnMoN 2. The reported redox-mediated stabilization in zinc molybdenum nitrides suggests there might be many undiscovered ternary compounds with one metal having an intermediate electronegativity, enabling significant covalent bonding, and another metal capable of accommodating multiple oxidation states, enabling stoichiometric flexibility.« less

Bioavailability of Lead in Small Arms Range Soils

DTIC Science & Technology

2009-08-01

titanium TOC total organic carbon USEPA U.S. Environmental Protection Agency XRF X-ray fluorescence Zn zinc Zr zirconium 1 1.0 EXECUTIVE...particles of inert matrix such as rock or slag of variable size, shape, and association; these chemical and physical properties may influence the absorption...zirconium, Pb=lead, Cu=copper, Mn=manganese, Si=silicon, Zn= zinc , As=arsenic, Cd=cadmium, CEC= cation exchange capacity, TOC = total organic carbon, Sb

Temperature effect on the structure and conformational fluctuations in two zinc knuckles from the mouse mammary tumor virus.

PubMed

Nedjoua, Drici; Krallafa, Abdelghani Mohamed

2018-06-01

Zinc fingers are small protein domains in which zinc plays a structural role, contributing to the stability of the zinc-peptide complex. Zinc fingers are structurally diverse and are present in proteins that perform a broad range of functions in various cellular processes, such as replication and repair, transcription and translation, metabolism and signaling, cell proliferation, and apoptosis. Zinc fingers typically function as interaction modules and bind to a wide variety of compounds, such as nucleic acids, proteins, and small molecules. In this study, we investigated the structural properties, in solution, of the proximal and distal zinc knuckles of the nucleocapsid (NC) protein from the mouse mammary tumor virus (MMTV) (MMTV NC). For this purpose, we performed a series of molecular dynamics simulations in aqueous solution at 300 K, 333 K, and 348 K. The temperature effect was evaluated in terms of root mean square deviation of the backbone atoms and root mean square fluctuation of the coordinating residue atoms. The stability of the zinc coordination sphere was analyzed based upon the time profile of the interatomic distances between the zinc ions and the chelator atoms. The results indicate that the hydrophobic character of the proximal zinc finger is dominant at 333 K. The low mobility of the coordinating residues suggests that the strong electrostatic effect exerted by the zinc ion on its coordinating residues is not influenced by the increase in temperature. The evolution of the structural parameters of the coordination sphere of the distal zinc finger at 300 K gives us a reasonable picture of the unfolding pathway, as proposed by Bombarda and coworkers (Bombarda et al., 2005), which can predict the binding order of the four conserved ligand-binding residues. Our results support the conclusion that the structural features can vary significantly between the two zinc knuckles of MMTV NC. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fabrication of an Organic Light-Emitting Diode from New Host π Electron Rich Zinc Complex

NASA Astrophysics Data System (ADS)

Jafari, Mohammad Reza; Janghouri, Mohammad; Shahedi, Zahra

2017-01-01

A new π electron rich zinc complex was used as a fluorescent material in organic light-emitting diodes (OLEDs). Devices with a structure of indium tin oxide/poly (3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT: PSS) (50 nm)/polyvinylcarbazole (60 nm)/Zn: %2 porphyrin derivatives (45 nm)/Al (150 nm) were fabricated. Porphyrin derivatives accounting for 2 wt.% in the π electron rich zinc complex were used as a host. The electroluminescence (EL) spectra of porphyrin derivatives indicated a red shift, as π electron rich zinc complex EL spectra. The device (4) has also a luminance of 3420 cd/m2 and maximum efficiency of 1.58 cd/A at 15 V, which are the highest values among four devices. The result of Commission International del'Eclairage (CIE) (X, Y) coordinate and EL spectrum of device (3) indicated that it is more red shifted compared to other devices. Results of this work indicate that π electron rich zinc complex is a promising host material for high efficiency red OLEDs and has a simple structure compared to Alq3-based devices.

Crosstalk between Zinc Status and Giardia Infection: A New Approach

PubMed Central

Astiazarán-García, Humberto; Iñigo-Figueroa, Gemma; Quihui-Cota, Luis; Anduro-Corona, Iván

2015-01-01

Zinc supplementation has been shown to reduce the incidence and prevalence of diarrhea; however, its anti-diarrheal effect remains only partially understood. There is now growing evidence that zinc can have pathogen-specific protective effects. Giardiasis is a common yet neglected cause of acute-chronic diarrheal illness worldwide which causes disturbances in zinc metabolism of infected children, representing a risk factor for zinc deficiency. How zinc metabolism is compromised by Giardia is not well understood; zinc status could be altered by intestinal malabsorption, organ redistribution or host-pathogen competition. The potential metal-binding properties of Giardia suggest unusual ways that the parasite may interact with its host. Zinc supplementation was recently found to reduce the rate of diarrhea caused by Giardia in children and to upregulate humoral immune response in Giardia-infected mice; in vitro and in vivo, zinc-salts enhanced the activity of bacitracin in a zinc-dose-dependent way, and this was not due to zinc toxicity. These findings reflect biological effect of zinc that may impact significantly public health in endemic areas of infection. In this paper, we shall explore one direction of this complex interaction, discussing recent information regarding zinc status and its possible contribution to the outcome of the encounter between the host and Giardia. PMID:26046395

[Lung disorders due to metals].

PubMed

Rüegger, M

1995-03-11

Though metals represent the largest group of elements they rather rarely cause respiratory diseases. This article will therefore review the most important ones caused by inhaled dusts of metals and some of their inorganic compounds, but leaving aside silicosis and silicatosis as well as iatrogenically induced metal pneumopathies. Among toxic inflammatory diseases metal fume fever, an influenza-like condition caused by zinc oxide, ranks as the commonest. Activities such as oxi-acetylene cutting and welding of zinc covered metal pieces account for about 90% of all cases compensated in Switzerland. Due to the non-recurrent character of this type of work, the typical waning of symptoms while exposure is going on has become seldom. Toxic pneumonia caused by inhaled metal fumes occurs rather seldom. However, serious cases have been reported where soldiers were exposed to zinc chloride from smoke bombs. The existence and extent of chronic airflow limitation due to occupational exposure to metallic dusts have not been widely examined but are to be assumed when there is poor occupational hygiene. Concerning asthma, there are at least four metals and several of their compounds which have been proven to cause variable airway narrowing, namely chromium, nickel, platinum and cobalt (the latter as hardmetal). Platinum complex salts (chloro-compounds) are very potent sensitizers leading to a notable prevalence of asthma among exposed workforces. Nevertheless, there have been no such cases in Switzerland for more than ten years. Hard-metal not only causes asthma but also an alveolitis-like interstitial lung disease progressing to fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Double Reformatsky reaction: divergent synthesis of δ-hydroxy-β-ketoesters.

PubMed

Mineno, Masahiro; Sawai, Yasuhiro; Kanno, Kazuaki; Sawada, Naotaka; Mizufune, Hideya

2013-06-21

The double Reformatsky reaction, tandem addition of two molecules of zinc alkanoate to a carbonyl compound, and its synthetic application to a series of δ-hydroxy-β-ketoesters has been developed. The key to accelerate the double Reformatsky reaction is considered to be a complex-induced proximity effect of the in situ generated zinc alkoxide coordinated with the pyridyl group of the substrate or bidentate amines. A noteworthy feature of the reaction system is its high tolerance of functional groups due to the moderate nucleophilicity of organozinc reagents and the mild reaction conditions. Moreover, spectroscopic and crystallographic analyses of the zinc complex of the double Reformatsky product support the proposed mechanism of reaction site discrimination for ketones, aldehydes, nitriles, carboxylic acid anhydrides, and esters.

Water- and Bed-Sediment Quality of Seguchie Creek and Selected Wetlands Tributary to Mille Lacs Lake in Crow Wing County, Minnesota, October 2003 to October 2006

USGS Publications Warehouse

Fallon, James D.; Yaeger, Christine S.

2009-01-01

Mille Lacs Lake and its tributaries, located in east-central Minnesota, are important resources to the public. In addition, many wetlands and lakes that feed Mille Lacs Lake are of high resource quality and vulnerable to degradation. Construction of a new four-lane expansion of U.S. Highway 169 has been planned along the western part of the drainage area of Mille Lacs Lake in Crow Wing County. Concerns exist that the proposed highway could affect the resource quality of surface waters tributary to Mille Lacs Lake. Baseline water- and bed-sediment quality characteristics of surface waters tributary to Mille Lacs Lake were needed prior to the proposed highway construction. The U.S. Geological Survey, in cooperation with the Minnesota Department of Transportation, characterized the water- and bed-sediment quality at selected locations that the proposed route intersects from October 2003 to October 2006. Locations included Seguchie Creek upstream and downstream from the proposed route and three wetlands draining to Mille Lacs Lake. The mean streamflow of Seguchie Creek increased between the two sites: flow at the downstream streamflow-gaging station of 0.22 cubic meter per second was 5.6 percent greater than the mean streamflow at the upstream streamflow-gaging station of 0.21 cubic meter per second. Because of the large amount of storage immediately upstream from both gaging stations, increases in flow were gradual even during intense precipitation. The ranges of most constituent concentrations in water were nearly identical between the two sampling sites on Seguchie Creek. No concentrations exceeded applicable water-quality standards set by the State of Minnesota. Dissolved-oxygen concentrations at the downstream gaging station were less than the daily minimum standard of 4.0 milligrams per liter for 6 of 26 measurements. Constituent loads in Seguchie Creek were greater at the downstream site than the upstream site for all measured, including dissolved chloride (1.7 percent), ammonia plus organic nitrogen (13 percent), total phosphorus (62 percent), and suspended sediment (11 percent) during the study. All constituents had seasonal peaks in spring and fall. The large loads during the fall resulted from unusually large precipitation and streamflow patterns. This caused the two greatest streamflow peaks at both sites to occur during October (2004 and 2005). In Seguchie Creek, bed-sediment concentrations of five metals and trace elements (arsenic, cadmium, chromium, lead, and zinc) exceeded the Interim Sediment Quality Guidelines (ISQG) set by the Canadian Council of Ministers of the Environment. Bed-sediment samples from the upstream site had more exceedances of ISQGs for metals and trace elements than did samples from the downstream site (seven and two exceedances, respectively). Bed-sediment samples from the downstream site had more exceedances of ISQGs (20 exceedances) for semivolatile organic compounds than did samples from the upstream site (8 exceedances), indicating different sources for organic compounds than for metals and trace elements. Concentrations of 11 semivolatile organic compounds exceeded ISQGs: ancenaphthene, acenaphthylene, anthracene, benzo[a]anthracene, benzo[a]pyrene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene. In bed-sediment samples collected from three wetlands, concentrations of all six metals exceeded ISQGs: arsenic, cadmium, chromium, copper, lead, and zinc. Concentrations of three semivolatile organic compounds exceeded ISQGs: flouranthene, phenanthrene, and pyrene. Results indicate that areas appearing relatively undisturbed and of high resource value can have degraded quality from previous unknown land use.

Synthesis aspects, structural, spectroscopic, antimicrobial and room temperature ferromagnetism of zinc iodide complex with Schiff based ligand

NASA Astrophysics Data System (ADS)

Shakila, K.; Kalainathan, S.

2015-01-01

In this paper, we report the successful growth of complex compound of zinc iodide with thiocarbamide by slow evaporation method. The single crystal XRD study reveals that the crystal belongs to monoclinic system with centrosymmetric space group and powder XRD analysis shows that the perfect crystalline nature of the crystal. The presence of functional group and element were confirmed from FT-IR and EDAX analysis. Optical absorbance of the grown crystal was studied by UV-Vis spectrophotometer. The optical constants were calculated from the optical absorbance data such as refractive index (n), extinction coefficient (K) and reflectance (R). The optical band gap (Eg) of thiocarbamide zinc iodide crystal is 4.22 eV. The magnetic properties of grown crystal have been determined by Vibrating Sample Magnetometry (VSM). Room temperature magnetization revealed a ferromagnetic behaviour for the grown crystal. The antibacterial and antifungal activities of the title compound were performed by well diffusion method and MIC method against the standard bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and against fungus like Aspergillus niger, Rhizopus sps and Penicillium sps. Thermal behaviour of the crystal has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA).

A compound crystal with film scintillator for electron detection

NASA Astrophysics Data System (ADS)

McKinney, George; McDonnald, Warren; Tzolov, Marian

2015-03-01

Yttrium Aluminum Garnets (YAG) and Yttrium Aluminum Perovskite (YAP) are widely used as electron detectors. This application requires a top conducting layer which hinders their application at low electron energies. We have developed a layer of zinc tungstate which delivers conductivity large enough to prevent charging while still being an efficient scintillator. For better coupling between the two systems we have studied their optical properties. Ce doping is an essential element in YAP and YAG in order for them to be efficient scintillators. We have studied the Ce content and we show that higher Ce content leads to reabsorption in the YAP scintillators. These details were revealed by using photoluminescence emission and excitation spectroscopy. The absorption spectrum for the YAG scintillators coincides with the excitation for the main emission lines. The optical studies of the zinc tungstate films and a single crystal have shown that the films are more efficient light emitters. We have integrated the zinc tungstate films with YAG scintillators and we will report on the performance of this compound scintillator. It is expected that it will perform well at low and high electron energies, which makes it a very cost effective platform for electron detectors.

Soil pH effects on the interactions between dissolved zinc, non-nano- and nano-ZnO with soil bacterial communities.

PubMed

Read, Daniel S; Matzke, Marianne; Gweon, Hyun S; Newbold, Lindsay K; Heggelund, Laura; Ortiz, Maria Diez; Lahive, Elma; Spurgeon, David; Svendsen, Claus

2016-03-01

Zinc oxide nanoparticles (ZnO NPs) are used in an array of products and processes, ranging from personal care products to antifouling paints, textiles, food additives, antibacterial agents and environmental remediation processes. Soils are an environment likely to be exposed to manmade nanoparticles due to the practice of applying sewage sludge as a fertiliser or as an organic soil improver. However, understanding on the interactions between soil properties, nanoparticles and the organisms that live within soil is lacking, especially with regards to soil bacterial communities. We studied the effects of nanoparticulate, non-nanoparticulate and ionic zinc (in the form of zinc chloride) on the composition of bacterial communities in soil with a modified pH range (from pH 4.5 to pH 7.2). We observed strong pH-dependent effects on the interaction between bacterial communities and all forms of zinc, with the largest changes in bacterial community composition occurring in soils with low and medium pH levels (pH 4.8 and 5.9). The high pH soil (pH 7.2) was less susceptible to the effects of zinc exposure. At the highest doses of zinc (2500 mg/kg dw soil), both nano and non-nano particulate zinc applications elicited a similar response in the soil bacterial community, and this differed significantly to the ionic zinc salt treatment. The results highlight the importance of considering soil pH in nanotoxicology studies, although further work is needed to determine the exact mechanisms controlling the toxicity and fate and interactions of nanoparticles with soil microbial communities.

Chemistry of Marine Ligands and Siderophores

PubMed Central

Vraspir, Julia M.; Butler, Alison

2011-01-01

Marine microorganisms are presented with unique challenges to obtain essential metal ions required to survive and thrive in the ocean. The production of organic ligands to complex transition metal ions is one strategy to both facilitate uptake of specific metals, such as iron, and to mitigate the potential toxic effects of other metal ions, such as copper. A number of important trace metal ions are complexed by organic ligands in seawater, including iron, cobalt, nickel, copper, zinc, and cadmium, thus defining the speciation of these metal ions in the ocean. In the case of iron, siderophores have been identified and structurally characterized. Siderophores are low molecular weight iron-binding ligands produced by marine bacteria. Although progress has been made toward the identity of in situ iron-binding ligands, few compounds have been identified that coordinate the other trace metals. Deciphering the chemical structures and production stimuli of naturally produced organic ligands and the organisms they come from is fundamental to understanding metal speciation and bioavailability. The current evidence for marine ligands, with an emphasis on siderophores, and discussion of the importance and implications of metal-binding ligands in controlling metal speciation and cycling within the world’s oceans are presented. PMID:21141029

Long life, rechargeable nickel-zinc battery

NASA Technical Reports Server (NTRS)

Luksha, E.

1974-01-01

A production version of the inorganic separator was evaluated for improving the life of the nickel-zinc system. Nickel-zinc cells (7-10 Ah capacities) of different electrode separator configurations were constructed and tested. The nickel-zinc cells using the inorganic separator encasing the zinc electrode, the nickel electrode, or both electrodes had shorter lives than cells using Visking and cellophane separation. Cells with the inorganic separation all fell below 70% of their theoretical capacity within 30 cycles, but the cells constructed with organic separation required 80 cycles. Failure of the cells using the ceramic separator was irreversible capacity degradation due to zinc loss through cracks developed in the inorganic separator. Zinc loss through the separator was minimized with the use of combinations of the inorganic separator with Visking and cellophane. Cells using the combined separation operated 130 duty cycles before degrading to 70% of their theoretical capacity.

The Nuclear Receptor HIZR-1 Uses Zinc as a Ligand to Mediate Homeostasis in Response to High Zinc

PubMed Central

Warnhoff, Kurt; Roh, Hyun C.; Kocsisova, Zuzana; Tan, Chieh-Hsiang; Morrison, Andrew; Croswell, Damari; Schneider, Daniel L.; Kornfeld, Kerry

2017-01-01

Nuclear receptors were originally defined as endocrine sensors in humans, leading to the identification of the nuclear receptor superfamily. Despite intensive efforts, most nuclear receptors have no known ligand, suggesting new ligand classes remain to be discovered. Furthermore, nuclear receptors are encoded in the genomes of primitive organisms that lack endocrine signaling, suggesting the primordial function may have been environmental sensing. Here we describe a novel Caenorhabditis elegans nuclear receptor, HIZR-1, that is a high zinc sensor in an animal and the master regulator of high zinc homeostasis. The essential micronutrient zinc acts as a HIZR-1 ligand, and activated HIZR-1 increases transcription of genes that promote zinc efflux and storage. The results identify zinc as the first inorganic molecule to function as a physiological ligand for a nuclear receptor and direct environmental sensing as a novel function of nuclear receptors. PMID:28095401

Structure Guided Chemical Modifications of Propylthiouracil Reveal Novel Small Molecule Inhibitors of Cytochrome b5 Reductase 3 That Increase Nitric Oxide Bioavailability*

PubMed Central

Rahaman, Md. Mizanur; Reinders, Fabio G.; Koes, David; Nguyen, Anh T.; Mutchler, Stephanie M.; Sparacino-Watkins, Courtney; Alvarez, Roger A.; Miller, Megan P.; Cheng, Dongmei; Chen, Bill B.; Jackson, Edwin K.; Camacho, Carlos J.; Straub, Adam C.

2015-01-01

NADH cytochrome b5 reductase 3 (CYB5R3) is critical for reductive reactions such as fatty acid elongation, cholesterol biosynthesis, drug metabolism, and methemoglobin reduction. Although the physiological and metabolic importance of CYB5R3 has been established in hepatocytes and erythrocytes, emerging investigations suggest that CYB5R3 is critical for nitric oxide signaling and vascular function. However, advancement toward fully understanding CYB5R3 function has been limited due to a lack of potent small molecule inhibitors. Because of this restriction, we modeled the binding mode of propylthiouracil, a weak inhibitor of CYB5R3 (IC50 = ∼275 μm), and used it as a guide to predict thiouracil-biased inhibitors from the set of commercially available compounds in the ZINC database. Using this approach, we validated two new potent derivatives of propylthiouracil, ZINC05626394 (IC50 = 10.81 μm) and ZINC39395747 (IC50 = 9.14 μm), both of which inhibit CYB5R3 activity in cultured cells. Moreover, we found that ZINC39395747 significantly increased NO bioavailability in renal vascular cells, augmented renal blood flow, and decreased systemic blood pressure in response to vasoconstrictors in spontaneously hypertensive rats. These compounds will serve as a new tool to examine the biological functions of CYB5R3 in physiology and disease and also as a platform for new drug development. PMID:26001785

Docking based virtual screening and molecular dynamics study to identify potential monoacylglycerol lipase inhibitors.

PubMed

Afzal, Obaid; Kumar, Suresh; Kumar, Rajiv; Firoz, Ahmad; Jaggi, Manu; Bawa, Sandhya

2014-08-15

Monoacylglycerol lipase (MAGL) is one of the key enzymes of the endocannabinoid system (ECS). It hydrolyzes one of the major endocannabinoid, 2-arachidonoylglycerol (2-AG), an endogenous full agonist at G protein coupled cannabinoid receptors CB1 and CB2. Numerous studies showed that MGL inhibitors are potentially useful for the treatment of pain, inflammation, cancer and CNS disorders. These provocative findings suggested that pharmacological inhibition of MAGL function may confer significant therapeutic benefits. In this study, we presented hybrid ligand and structure-based approaches to obtain a novel set of virtual leads as MAGL inhibitors. The constraints used in this study, were Glide score, binding free energy estimates and ADME properties to screen the ZINC database, containing approximately 21 million compounds. A total of seven virtual hits were obtained, which showed significant binding affinity towards MAGL protein. Ligand, ZINC24092691 was employed in complex form with the protein MAGL, for molecular dynamics simulation study, because of its excellent glide score, binding free energy and ADME properties. The RMSD of ZINC24092691 was observed to stay at 0.1 nm (1 Å) in most of the trajectories, which further confirmed its ability to inhibit the protein MAGL. The hits were then evaluated for their ability to inhibit human MAGL. The compound ZINC24092691 displayed the noteworthy inhibitory activity reducing MAGL activity to 21.15% at 100 nM concentration, with an IC50 value of 10 nM. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ecotoxicological risk assessment of hospital wastewater: a proposed framework for raw effluents discharging into urban sewer network.

PubMed

Emmanuel, E; Perrodin, Y; Keck, G; Blanchard, J-M; Vermande, P

2005-01-14

In hospitals a large variety of substances are in use for medical purposes such as diagnostics and research. After application, diagnostic agents, disinfectants and excreted non-metabolized pharmaceuticals by patients, reach the wastewater. This form of elimination may generate risks for aquatic organisms. The aim of this study was to present: (i) the steps of an ecological risk assessment and management framework related to hospital effluents evacuating into wastewater treatment plant (WWTP) without preliminary treatment; and (ii) the results of its application on wastewater from an infectious and tropical diseases department of a hospital of a large city in southeastern France. The characterization of effects has been made under two assumptions, which were related to: (a) the effects of hospital wastewater on biological treatment process of WWTP, particularly on the community of organisms in charge of the biological decomposition of the organic matter; (b) the effects on aquatic organisms. COD and BOD5 have been measured for studying global organic pollution. Assessment of halogenated organic compounds was made using halogenated organic compounds absorbable on activated carbon (AOX) concentrations. Heavy metals (arsenic, cadmium, chrome, copper, mercury, nickel, lead and zinc) were measured. Low most probable number (MPP) for faecal coliforms has been considered as an indirect detection of antibiotics and disinfectants presence. For toxicity assessment, bioluminescence assay using Vibrio fischeri photobacteria, 72-h EC50 algae growth Pseudokirchneriella subcapitata and 24-h EC50 on Daphnia magna were used. The scenario allows to a semi-quantitative risk characterization. It needs to be improved on some aspects, particularly those linked to: long term toxicity assessment on target organisms (bioaccumulation of pollutants, genotoxicity, etc.); ecotoxicological interactions between pharmaceuticals, disinfectants used both in diagnostics and in cleaning of surfaces, and detergents used in cleaning of surfaces; the interactions into the sewage network, between the hospital effluents and the aquatic ecosystem.

Influence of thickness of zinc coating on CMT welding-brazing with AlSi5 alloy wire

NASA Astrophysics Data System (ADS)

Jin, Pengli; Wang, Zhiping; Yang, Sinan; Jia, Peng

2018-03-01

Effect of thickness of zinc coating on Cold Mattel Transfer (CMT) brazing of aluminum and galvanized steel is investigated. The thickness of zinc coating is 10 μm, 30 μm, and 60 μm, respectively. A high-speed camera was used to capture images of welding process of different specimens; the microstructure and composition analyses of the welding seam were examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS); the mechanical properties were measured in the form of Nano-indentation experiments. The results showed that arc characteristics and metal transfer behavior were unsteady at the beginning of welding process and that became stable after two cycles of CMT. With the thickness of zinc coating thickening, arc characteristics and metal transfer behaviors were more deteriorated. Compared with 10 μm and 30 μm, clad appearance of 60 μm was straight seam edges and a smooth surface which wetting angle was 60°. Zinc-rich zone at the seam edges was formed by zinc dissolution and motel pool oscillating, and zinc content of 10 μm and 30 μm were 5.8% and 7.75%. Zinc content of 60 μm was 14.61%, and it was a belt between galvanized steel and welding seam. The thickness of intermetallic compounds layer was in the range of 1-8 μm, and it changed with the thickness of zinc coating. The average hardness of the reaction layer of 60 μm is 9.197 GPa.

Amphiphilic zinc phthalocyanine photosensitizers: synthesis, photophysicochemical properties and in vitro studies for photodynamic therapy.

PubMed

Çakır, Dilek; Göksel, Meltem; Çakır, Volkan; Durmuş, Mahmut; Biyiklioglu, Zekeriya; Kantekin, Halit

2015-05-28

Peripherally and non-peripherally tetra-substituted zinc(ii) phthalocyanines bearing 2-(2-{2-[3-(dimethylamino)phenoxy]ethoxy}ethoxy)ethoxy and 2-(2-{2-[3-(diethylamino)phenoxy]ethoxy}ethoxy)ethoxy groups (, , and ) were synthesized by cyclotetramerization of the corresponding phthalonitriles (, , and ). Their quaternized ionic derivatives (, , and ) were also synthesized by the reaction of them with methyl iodide. The novel compounds were characterized by using standard spectroscopic techniques such as FT-IR, (1)H NMR, (13)C NMR, UV-vis, mass and elemental analyses. The obtained quaternized phthalocyanines (, , and ) showed amphiphilic behaviour with excellent solubility in both organic and aqueous solutions, which makes them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yields) properties of these novel phthalocyanines were studied in DMSO for both non-ionic and ionic quaternized derivatives. However, these properties were examined in both DMSO and phosphate buffer solution (PBS) for quaternized ionic phthalocyanines. The effects of the positions of substituents (peripheral or non-peripheral) and the quaternization of the nitrogen atoms on the substituents about their photophysical and photochemical properties were also compared in this study. The bovine serum albumin (BSA) binding behaviours of the studied quaternized ionic zinc(ii) phthalocyanines were also described in PBS solutions. The quaternized phthalocyanines (, , and ) successfully displayed light-dependent photodamage in HeLa and HuH-7 cancer cells in photodynamic therapy treatment. The photosensitivity and the intensity of damage were found directly related to the concentration of the photosensitizers.

Respiratory Symptoms and Pulmonary Function Tests among Galvanized Workers Exposed To Zinc Oxide.

PubMed

Aminian, Omid; Zeinodin, Hamidreza; Sadeghniiat-Haghighi, Khosro; Izadi, Nazanin

2015-01-01

Galvanization is the process of coating steel or cast iron pieces with a thin layer of zinc allowing protection against corrosion. One of the important hazards in this industry is exposure to zinc compounds specially zinc oxide fumes and dusts. In this study, we evaluated chronic effects of zinc oxide on the respiratory tract of galvanizers. Overall, 188 workers were selected from Arak galvanization plant in 2012, 71 galvanizers as exposed group and 117 workers from other departments of plants as control group. Information was collected using American Thoracic Society (ATS) standard questionnaire, physical examination and demographic data sheet. Pulmonary function tests were measured for all subjects. Exposure assessment was done with NIOSH 7030 method. The Personal Breathing Zone (PBZ) air sampling results for zinc ranged from 6.61 to 8.25 mg/m³ above the permissible levels (Time weighted average; TWA:2 mg/m³). The prevalence of the respiratory symptoms such as dyspnea, throat and nose irritation in the exposed group was significantly (P<0.01) more than the control group. Decreasing in average percent in all spirometric parameters were seen in the galvanizers who exposed to zinc oxide fumes and dusts. The prevalence of obstructive respiratory disease was significantly (P=0.034) higher in the exposed group. High workplace zinc levels are associated with an increase in respiratory morbidity in galvanizers. Therefore administrators should evaluate these workers with periodic medical examinations and implement respiratory protection program in the working areas.

Marine Ecological Risk Assessment Pilot Study for Allen Harbor, Narragansett Bay, Rhode Island

DTIC Science & Technology

1992-01-01

evidence of major contamination in sediments or tissues except for relatively high levels of polychlorinated biphenols (PBC), butyltins compounds ( TBT ...biphenols (PBC), butyltin compounds ( TBT ), and fecal coliforms observed in Allen Harbor. Effects were detected in mussel physiology, sea urchin fertilization...Dichiorodiphenyl- dichioroethene HBC - Hexachlorobenzene TBT -Thbutyltin METALS Cu - Copper Zn -Zinc Cr - Chromium Pb -Lead Ni - Nickel As - Arsenic

Natural allelic variation of the AZI1 gene controls root growth under zinc-limiting condition

PubMed Central

Bouain, Nadia; Saenchai, Chorpet

2018-01-01

Zinc is an essential micronutrient for all living organisms and is involved in a plethora of processes including growth and development, and immunity. However, it is unknown if there is a common genetic and molecular basis underlying multiple facets of zinc function. Here we used natural variation in Arabidopsis thaliana to study the role of zinc in regulating growth. We identify allelic variation of the systemic immunity gene AZI1 as a key for determining root growth responses to low zinc conditions. We further demonstrate that this gene is important for modulating primary root length depending on the zinc and defence status. Finally, we show that the interaction of the immunity signal azelaic acid and zinc level to regulate root growth is conserved in rice. This work demonstrates that there is a common genetic and molecular basis for multiple zinc dependent processes and that nutrient cues can determine the balance of growth and immune responses in plants. PMID:29608565

Assessment of environmental effects of the coal used in the Seyitomer thermal power plant (Turkey) on white willow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cicek, A.; Koparal, A.S.

2006-07-01

Thermal power plants increase local pollution through SOx, NOx, volatile organic compounds (VOCs), and oils containing primarily particulates (including heavy metals) and increase global pollution through CO{sub 2}, the greenhouse gas that causes global warming. These strong pollutants have harmful effects on living organisms and the entire ecosystem. In this study, we analysed the heavy metals iron (Fe), cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and sulfur (S) induced by sulfur dioxide found in both the washed and unwashed leaves of Salix alba L. tree, grown in six distinct localities in the vicinity of themore » Seyitomer thermal power plant, to assess the environmental impact. All parameters were examined in the surface soils (0-30 cm), and the most intense concentration of the pollutants in both soils and leaves was observed to be in the direction of the prevailing wind.« less

Water quality in the Sugar Creek basin, Bloomington and Normal, Illinois

USGS Publications Warehouse

Prugh, Byron J.

1978-01-01

Urban runoff and overflows from combined sewers affect water quantity and quality in Sugar Creek within the twin cities of Bloomington and Normal, Illinois. Water-quality data from five primary and eight secondary locations showed three basic types of responses to climatic and hydrologic stresses. Stream temperatures and concentrations of dissolved oxygen, ammonia nitrogen, total phosphorus, biochemical oxygen demand, and fecal bacteria showed seasonal variations. Specific conductivity, pH, chloride, and suspended solids concentrations varied more closely with stream discharges. Total organic carbon, total nitrogen, total phosphorus, biochemical oxygen demand, and fecal coliform and fecal streptococcal bacteria concentrations exhibited variations indicative of intial flushing action during storm runoff. Selected analyses for herbicides, insecticides, and other complex organic compounds in solution and in bed material showed that these constituents were coming from sources other than the municipal sanitary treatment plant effluent. Analyses for 10 common metals: arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, and zinc showed changes in concentrations below the municipal sanitary plant outfall. (Woodard-USGS)

Zinc in Early Life: A Key Element in the Fetus and Preterm Neonate

PubMed Central

Terrin, Gianluca; Berni Canani, Roberto; Di Chiara, Maria; Pietravalle, Andrea; Aleandri, Vincenzo; Conte, Francesca; De Curtis, Mario

2015-01-01

Zinc is a key element for growth and development. In this narrative review, we focus on the role of dietary zinc in early life (including embryo, fetus and preterm neonate), analyzing consequences of zinc deficiency and adequacy of current recommendations on dietary zinc. We performed a systematic search of articles on the role of zinc in early life. We selected and analyzed 81 studies. Results of this analysis showed that preservation of zinc balance is of critical importance for the avoidance of possible consequences of low zinc levels on pre- and post-natal life. Insufficient quantities of zinc during embryogenesis may influence the final phenotype of all organs. Maternal zinc restriction during pregnancy influences fetal growth, while adequate zinc supplementation during pregnancy may result in a reduction of the risk of preterm birth. Preterm neonates are at particular risk to develop zinc deficiency due to a combination of different factors: (i) low body stores due to reduced time for placental transfer of zinc; (ii) increased endogenous losses; and (iii) marginal intake. Early diagnosis of zinc deficiency, through the measurement of serum zinc concentrations, may be essential to avoid severe prenatal and postnatal consequences in these patients. Typical clinical manifestations of zinc deficiency are growth impairment and dermatitis. Increasing data suggest that moderate zinc deficiency may have significant subclinical effects, increasing the risk of several complications typical of preterm neonates (i.e., necrotizing enterocolitis, chronic lung disease, and retinopathy), and that current recommended intakes should be revised to meet zinc requirements of extremely preterm neonates. Future studies evaluating the adequacy of current recommendations are advocated. PMID:26690476

Determination of silver, bismuth, cadmium, copper, lead, and zinc in geologic materials by atomic absorption spectrometry with tricaprylylmethylammonium chloride

USGS Publications Warehouse

Viets, J.G.

1978-01-01

Interferences commonly encountered in the determination of silver, bismuth, cadmium, copper, lead, and zinc at crustal abundance levels are effectively eliminated using a rapid, sensitive, organic extraction technique. A potassium chlorate-hydrochloric acid digestion solubilizes the metals not tightly bound in the silicate lattice of rocks, soils, and stream sediments. The six metals are selectively extracted into a 10% Aliquat 336-MIBK organic phase in the presence of ascorbic acid and potassium iodide. Metals in the organic extract are determined by flame atomic absorption spectrometry to the 0.02-ppm level for silver, cadmium, copper, and zinc and to the 0.2-ppm level for bismuth and lead with a maximum relative standard deviation of 18.8% for known reference samples. An additional hydrofluoric acid digestion may be used to determine metals substituted in the silicate lattice.

In-situ evaluation of barrier-cream performance on human skin using laser-induced breakdown spectroscopy.

PubMed

Sun, Q; Tran, M; Smith, B; Winefordner, J D

2000-11-01

Laser-induced breakdown spectroscopy (LIBS) was used to evaluate the effect of barrier creams (skin protective creams) on human skin. A Nd: YAG laser at 1,064 nm was used with a pulse energy of 100 mJ. A method was developed to measure the effectiveness of barrier creams against zinc ion absorption from aqueous zinc chloride solution and oil paste zinc oxide, which represent model hydrophilic and lipophilic metal compounds, respectively. Zinc was chosen since it posed no risk to human skin. 3 representative commercial barrier creams advertised as being effective against lipophilic and hydrophilic substances were evaluated by measuring zinc absorbed through the stratum corneum. 4 consecutive skin surface biopsies (SSB) were taken from biceps of the forearms of 6 volunteers at time periods of 0.5 h and 3 h after application of the protective cream. Results were compared with control skin where no barrier cream was used. The zinc atomic emission line at 213.9 nm was selected. Gate delay and gate width time was optimized to obtain the best signal-to-noise ratio (SNR) and precision. This method provided a facile and rapid screening of the effectiveness of skin barrier creams against zinc ion penetration. The barrier creams were shown to provide appreciable protection against the penetration of both ZnCl2 and ZnO into the skin.

Two mechanisms of oral malodor inhibition by zinc ions.

PubMed

Suzuki, Nao; Nakano, Yoshio; Watanabe, Takeshi; Yoneda, Masahiro; Hirofuji, Takao; Hanioka, Takashi

2018-01-18

The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria.

Two mechanisms of oral malodor inhibition by zinc ions

PubMed Central

Suzuki, Nao; Nakano, Yoshio; Watanabe, Takeshi; Yoneda, Masahiro; Hirofuji, Takao; Hanioka, Takashi

2018-01-01

Abstract Objectives The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. Material and Methods The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Results Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Conclusions Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria. PMID:29364345

Synthesis and characterization of two new zinc(II) coordination polymers with bidentate flexible ligands: Formation of a 2D structure with (44.62)-sql topology

NASA Astrophysics Data System (ADS)

Lalegani, Arash; Khaledi Sardashti, Mohammad; Gajda, Roman; Woźniak, Krzysztof

2017-12-01

Zinc(II) coordination polymers [Zn(bip)2(NCS)2]n (1) and [Zn(μ-bbd)(N3)2]n (2) were synthesized by using the neutral flexible bidentate N-donor ligands 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd) and 1,3-bis(imidazolyl)propane (bip), mono-anionic NCS- or N3-ligand and zinc(II) chloride salts. The results of the X-ray analyses demonstrate that in the structure of 1, the zinc(II) ion is located on an inversion center and exhibits an ZnN6 octahedral arrangement while, in the structure of 2, the zinc(II) ion adopts an ZnN4 tetrahedral geometry. In the polymer 1, the NCS groups are terminally N-bonded to the metal center and the each bip with anti-gauche conformation acts as bridging connecting four zinc(II) ions to form a two-dimensional network with a sql [point symbol (44.62)] topology while, in the polymer 1, the N3 groups are terminally bonded to the metal center and each bbd with anti-anti-anti conformation acts as bridging ligand connecting two zinc(II) ions to form a one-dimensional zig-zag chain. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. Thermal analyses of polymers were also presented.

Comparative study of the marginal microleakage of six cements in fixed provisional crowns.

PubMed

Baldissara, P; Comin, G; Martone, F; Scotti, R

1998-10-01

In many situations, provisional restorations require a long-term permanence in the oral cavity. During this period, the abutments need the best possible biologic and mechanical protection. In this way, the vitality of the pulp and the integrity of mineralized tissues can be preserved. The luting cement used to fix interim restorations should have good mechanical properties, low solubility, and good adhesion to resist bacterial and molecular penetration. However, because of its provisional nature, the prosthesis should be easy to remove from the abutments. These contrasting requirements may lead to a compromise in cement behavior, particularly in its mechanical properties. This in vitro study evaluated the marginal microleakage of 4 provisional cements, a cavity base compound and a zinc-phosphate luting cement in provisional acrylic resin crowns fixed on extracted human teeth. Thirty acrylic resin crowns were made and fitted on intact human premolars with the 6 cements. All restorations were applied in a standardized manner by means of an axial load of 10 kg. Specimens were thermocycled then submerged in a 5% basic fuchsin solution, then sectioned and observed under a light stereomicroscope. A 5-level scale was used to score dye penetration in the tooth/cement interface. A high dye penetration in the tooth/cement interface was present in all 4 provisional cements. Microleakage existed in specimens where zinc-phosphate and cavity base compounds were used; however, it was lower than the other materials. A significant difference (P < .05) was found between zinc-phosphate and one eugenol-free cement and between cavity base and the same eugenol-free cement. All materials tested demonstrated different degrees of microleakage. Zinc-phosphate and cavity base compound cements had the best sealing properties. This latter, even if conceived as a cavity base, may be considered a good provisional cement as far as microleakage is concerned.

Accelerated bridge paint test program.

DOT National Transportation Integrated Search

2011-07-06

The accelerated bridge paint (AB-Paint) program evaluated a new Sherwin-Williams two-coat, : fast-curing paint system. The system is comprised of an organic zinc-rich primer (SW Corothane I : Galvapac One-Pack Zinc-Rich Primer B65 G11) and a polyurea...

Indium: bringing liquid-crystal displays into focus

USGS Publications Warehouse

Mercer, Celestine N.

2015-07-30

Compared to more abundant industrial metals such as lead and zinc, information about the behavior and toxicity of indium in the environment is limited. However, many indium compounds have been proven to be toxic to animals.

Impact of glutathione metabolism on zinc homeostasis in Saccharomyces cerevisiae.

PubMed

Steiger, Matthias G; Patzschke, Anett; Holz, Caterina; Lang, Christine; Causon, Tim; Hann, Stephan; Mattanovich, Diethard; Sauer, Michael

2017-06-01

Zinc is a crucial mineral for all organisms as it is an essential cofactor for the proper function of a plethora of proteins and depletion of zinc causes oxidative stress. Glutathione is the major redox buffering agent in the cell and therefore important for mitigation of the adverse effects of oxidative stress. In mammalian cells, zinc deficiency is accompanied by a glutathione depletion. In the yeast Saccharomyces cerevisiae, the opposite effect is observed: under low zinc conditions, an elevated glutathione concentration is found. The main regulator to overcome zinc deficiency is Zap1p. However, we show that Zap1p is not involved in this glutathione accumulation phenotype. Furthermore, we found that in glutathione-accumulating strains also the metal ion-binding phytochelatin-2, which is an oligomer of glutathione, is accumulated. This increased phytochelatin concentration correlates with a lower free zinc level in the vacuole. These results suggest that phytochelatin is important for zinc buffering in S. cerevisiae and thus explains how zinc homeostasis is connected with glutathione metabolism. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Biocatalytic trifluoromethylation of unprotected phenols

NASA Astrophysics Data System (ADS)

Simon, Robert C.; Busto, Eduardo; Richter, Nina; Resch, Verena; Houk, Kendall N.; Kroutil, Wolfgang

2016-11-01

Organofluorine compounds have become important building blocks for a broad range of advanced materials, polymers, agrochemicals, and increasingly for pharmaceuticals. Despite tremendous progress within the area of fluorination chemistry, methods for the direct introduction of fluoroalkyl-groups into organic molecules without prefunctionalization are still highly desired. Here we present a concept for the introduction of the trifluoromethyl group into unprotected phenols by employing a biocatalyst (laccase), tBuOOH, and either the Langlois' reagent or Baran's zinc sulfinate. The method relies on the recombination of two radical species, namely, the phenol radical cation generated directly by the laccase and the CF3-radical. Various functional groups such as ketone, ester, aldehyde, ether and nitrile are tolerated. This laccase-catalysed trifluoromethylation proceeds under mild conditions and allows accessing trifluoromethyl-substituted phenols that were not available by classical methods.

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

PubMed Central

2013-01-01

Background Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Results Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Conclusions Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems. PMID:23849189

Chemical characteristics of urban stormwater sediments and implications for environmental management, Maricopa County, Arizona

USGS Publications Warehouse

Parker, J.T.C.; Fossum, K.D.; Ingersoll, T.L.

2000-01-01

Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.

Proceedings of the symposium on Nuclear Radiation Detection Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perry, D.L.; Burger, A.; Franks, L.

2008-07-01

This symposium provides a venue for the presentation of the latest results and discussion of radiation detection materials from both experimental and theoretical standpoints. As advances are made in this area of materials, additional experimental and theoretical approaches are used to both guide the growth of materials and to characterize the materials that have a wide array of applications for detecting different types of radiation. The types of detector materials for semiconductors and scintillators include a variety of molecular compounds such as lanthanum halides (LaX{sub 3}), zinc oxide (ZnO), lead iodide (PbI{sub 2}), cadmium telluride (CdTe), mercuric iodide (HgI{sub 2}),more » thallium bromide (TlBr), as well as others, such as cadmium zinc telluride (CZT). An additional class of scintillators includes those based on organic compounds and glasses. Ideally, desired materials used for radiation detection have attributes such as appropriate-range band-gaps, high atomic numbers of the central element, high densities, performance at room temperature, and strong mechanical properties, and are low cost in terms of their production. There are significant gaps in the knowledge related to these materials that are very important in making radiation detector materials that are higher quality in terms of their reproducible purity, homogeneity, and mechanical integrity. The topics that are the focal point of this symposium address these issues so that much better detectors may be made in the future. Topics cover the following areas: - Material growth: on-going developments regarding cadmium telluride (CdTe), cadmium zinc telluride (CZT), mercuric iodide (HgI{sub 2}), cadmium manganese telluride (CMT), LaX{sub 3}, and all other detector materials; new materials with potential for radiation detection (II-VI, III-VI, III-VII compounds, neutron detectors, nano-materials, and ceramic scintillators); purification techniques; and growth methods; - Characterization: experimental results; methodologies; defect structure; surface and bulk effects; and interfacial phenomena (contacting, contact adhesion, crystallographic polarity, Schottky barrier, and surface passivation); - Physical and mechanical properties: electric charge compensation mechanisms, charge collection, and thermal transport; hardness; and plasticity; - New and innovative characterization techniques: optical spectroscopy; microscopy (SEM, TEM, STM, AFM, etc.); synchrotron mapping and X-ray diffraction; rocking curves; and spectroscopy (IR, Raman, NMR, XPS, Auger, and other applicable approaches); - Theoretical studies: bandgap calculations; mobility calculations; scintillator material physics; thermal modeling; crystal growth; processes in material matrices; and processes in amorphous and crystalline matrices.« less

Ground-water quality in the Lake Champlain basin, New York, 2004

USGS Publications Warehouse

Nystrom, Elizabeth A.

2006-01-01

Water samples were collected from 11 public-supply wells and 11 private domestic wells in the Lake Champlain basin in New York during the fall of 2004 to characterize the chemical quality of ground water. Wells were selected for sampling based on location and focused on areas of greatest ground-water use. Samples were analyzed for 219 physical properties and constituents, including inorganic compounds, nutrients, metals, radionuclides, pesticides and pesticide degradates, volatile organic compounds, and bacteria. Sixty-eight constituents were detected at concentrations above laboratory reporting levels. The cation and anion with the highest median concentration were calcium (34.8 mg/L) bicarbonate (134 mg/L), respectively. The predominant nutrient was nitrate, which was detected in 14 (64 percent) of the 22 samples. The two metals with the highest median concentrations were iron (175 ?g/L) and strontium (124 ?g/L); concentrations of iron, manganese, aluminum, and zinc exceeded U.S. Environmental Protection Agency secondary drinking-water standards in one or more samples. Radon concentrations were less than 1,000 picocuries per liter (pCi/L) in most samples, but concentrations as high as 6,900 pCi/L were detected and, in eight samples, exceeded the U.S. Environmental Protection Agency proposed maximum contaminant level (300 pCi/L) for radon. The most frequently detected pesticides were degradates of the broadleaf herbicides metolachlor, alachlor, and atrazine. Volatile organic compounds were detected in only three samples; those that were detected typically were fuel oxygenates, such as methyl tert-butyl ether. Coliform bacteria were detected in four samples, two of which also tested positive for E. coli.

Development of metal-chelating inhibitors for the Class II fructose 1,6-bisphosphate (FBP) aldolase.

PubMed

Labbé, Geneviève; Krismanich, Anthony P; de Groot, Sarah; Rasmusson, Timothy; Shang, Muhong; Brown, Matthew D R; Dmitrienko, Gary I; Guillemette, J Guy

2012-07-01

It has long been suggested that the essential and ubiquitous enzyme fructose 1,6-bisphosphate (FBP) aldolase could be a good drug target against bacteria and fungi, since lower organisms possess a metal-dependant (Class II) FBP aldolase, as opposed to higher organisms which possess a Schiff-base forming (Class I) FBP aldolase. We have tested the capacity of derivatives of the metal-chelating compound dipicolinic acid (DPA), as well a thiol-containing compound, to inhibit purified recombinant Class II FBP aldolases from Mycobacterium tuberculosis, Pseudomonas aeruginosa, Bacillus cereus, Bacillus anthracis, and from the Rice Blast causative agent Magnaporthe grisea. The aldolase from M. tuberculosis was the most sensitive to the metal-chelating inhibitors, with an IC(50) of 5.2 μM with 2,3-dimercaptopropanesulfonate (DMPS) and 28 μM with DPA. DMPS and the synthesized inhibitor 6-(phosphonomethyl)picolinic acid inhibited the enzyme in a time-dependent, competitive fashion, with second order rate constants of 273 and 270 M(-1) s(-1) respectively for the binding of these compounds to the M. tuberculosis aldolase's active site in the presence of the substrate FBP (K(M) 27.9 μM). The most potent first generation inhibitors were modeled into the active site of the M. tuberculosis aldolase structure, with results indicating that the metal chelators tested cannot bind the catalytic zinc in a bidentate fashion while it remains in its catalytic location, and that most enzyme-ligand interactions involve the phosphate binding pocket residues. Copyright © 2012 Elsevier Inc. All rights reserved.

Germanium and indium

USGS Publications Warehouse

Shanks, W.C. Pat; Kimball, Bryn E.; Tolcin, Amy C.; Guberman, David E.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Germanium and indium are two important elements used in electronics devices, flat-panel display screens, light-emitting diodes, night vision devices, optical fiber, optical lens systems, and solar power arrays. Germanium and indium are treated together in this chapter because they have similar technological uses and because both are recovered as byproducts, mainly from copper and zinc sulfides.The world’s total production of germanium in 2011 was estimated to be 118 metric tons. This total comprised germanium recovered from zinc concentrates, from fly ash residues from coal burning, and from recycled material. Worldwide, primary germanium was recovered in Canada from zinc concentrates shipped from the United States; in China from zinc residues and coal from multiple sources in China and elsewhere; in Finland from zinc concentrates from the Democratic Republic of the Congo; and in Russia from coal.World production of indium metal was estimated to be about 723 metric tons in 2011; more than one-half of the total was produced in China. Other leading producers included Belgium, Canada, Japan, and the Republic of Korea. These five countries accounted for nearly 95 percent of primary indium production.Deposit types that contain significant amounts of germanium include volcanogenic massive sulfide (VMS) deposits, sedimentary exhalative (SEDEX) deposits, Mississippi Valley-type (MVT) lead-zinc deposits (including Irish-type zinc-lead deposits), Kipushi-type zinc-lead-copper replacement bodies in carbonate rocks, and coal deposits.More than one-half of the byproduct indium in the world is produced in southern China from VMS and SEDEX deposits, and much of the remainder is produced from zinc concentrates from MVT deposits. The Laochang deposit in Yunnan Province, China, and the VMS deposits of the Murchison greenstone belt in Limpopo Province, South Africa, provide excellent examples of indium-enriched deposits. The SEDEX deposits at Bainiuchang, China (located in southeastern Yunnan Province), and the Dabaoshan SEDEX deposit (located in the Nanling region of China) contain indium-enriched sphalerite. Another major potential source of indium occurs in the polymetallic tin-tungsten belt in the Eastern Cordillera of the Andes Mountains of Bolivia. Deposits there occur as dense arrays of narrow, elongate, indium-enriched tin oxide-polymetallic sulfide veins in volcanic rocks and porphyry stocks.Information about the behavior of germanium and indium in the environment is limited. In surface weathering environments, germanium and indium may dissolve from host minerals and form complexes with chloride, fluoride, hydroxide, organic matter, phosphate, or sulfate compounds. The tendency for germanium and indium to be dissolved and transported largely depends upon the pH and temperature of the weathering solutions. Because both elements are commonly concentrated in sulfide minerals, they can be expected to be relatively mobile in acid mine drainage where oxidative dissolution of sulfide minerals releases metals and sulfuric acid, resulting in acidic pH values that allow higher concentrations of metals to be dissolved into solution.

Ground-water quality beneath an urban residential and commercial area, Montgomery, Alabama, 1999-2000

USGS Publications Warehouse

Robinson, James L.

2002-01-01

The Black Warrior River aquifer, which is composed of the Coker, Gordo, and Eutaw Formations, supplies more than 50 percent of the ground water used for public water supply in the Mobile River Basin. The city of Montgomery, Alabama, is partially built upon a recharge area for the Black Warrior River aquifer, and is one of many major population centers that depend on the Black Warrior River aquifer for public water supply. To represent the baseline ground-water quality in the Black Warrior River aquifer, water samples were collected from 30 wells located in a low-density residential or rural setting; 9 wells were completed in the Coker Formation, 9 wells in the Gordo Formation, and 12 wells in the Eutaw Formation. To describe the ground-water quality beneath Montgomery, Alabama, water samples also were collected from 30 wells located in residential and commercial areas of Montgomery, Alabama; 16 wells were completed in the Eutaw Formation, 8 wells in alluvial deposits, and 6 wells in terrace deposits. The alluvial and terrace deposits directly overlie the Eutaw Formation with little or no hydraulic separation. Ground-water samples collected from both the rural and urban wells were analyzed for physical properties, major ions, nutrients, metals, volatile organic compounds, and pesticides. Samples from the urban wells also were analyzed for bacteria, chlorofluorocarbons, dissolved gases, and sulfur hexafluoride. Ground-water quality beneath the urban area was compared to baseline water quality in the Black Warrior River aquifer.Compared to the rural wells, ground-water samples from urban wells contained greater concentrations or more frequent detections of chloride and nitrate, and the trace metals aluminium, chromium, cobalt, copper, nickel, and zinc. Pesticides and volatile organic compounds were detected more frequently and in greater concentrations in ground-water samples collected from urban wells than in ground-water samples from rural wells.The Spearman rho test was used to check for statistically significant covariance among urban ground-water quality and land-use type. The number of pesticides and volatile organic compounds detected and concentrations of nickel increased as the percentage of residential land use increased. Greater nickel concentrations also were associated with a greater number of volatile organic compounds detected. As the percentage of commercial land use increased, the numbers of pesticides and volatile organic compounds detected decreased. The number of pesticides detected in the urban ground-water samples increased as concentrations of nitrite plus nitrate increased; the number of pesticides detected and the concentrations of nitrite plus nitrate decreased as the age of the ground water increased. These correlations may indicate that, with time, pesticides and nitrate are removed from the ground-water system by physical, chemical, or biological processes.The effects of surficial geology on the occurrence of pesticides and volatile organic compounds was investigated by calculating frequencies of detection. The detection frequency for pesticides was greater for urban samples collected from wells where the surficial geology is sand than for urban samples collected from wells where the surficial geology is clay. The frequency of detection of volatile organic compounds did not show this relation.

Zinc stress induces copper depletion in Acinetobacter baumannii.

PubMed

Hassan, Karl A; Pederick, Victoria G; Elbourne, Liam D H; Paulsen, Ian T; Paton, James C; McDevitt, Christopher A; Eijkelkamp, Bart A

2017-03-11

The first row transition metal ions zinc and copper are essential to the survival of many organisms, although in excess these ions are associated with significant toxicity. Here, we examined the impact of zinc and copper stress on Acinetobacter baumannii, a common opportunistic pathogen. We show that extracellular zinc stress induces a copper-specific depletion phenotype in A. baumannii ATCC 17978. Supplementation with copper not only fails to rescue this phenotype, but further exacerbates the copper depletion. Extensive analysis of the A. baumannii ATCC 17978 genome identified 13 putative zinc/copper resistance efflux pumps. Transcriptional analyses show that four of these transporters are responsive to zinc stress, five to copper stress and seven to the combination of zinc and copper stress, thereby revealing a likely foundation for the zinc-induced copper starvation in A. baumannii. In addition, we show that zinc and copper play crucial roles in management of oxidative stress and the membrane composition of A. baumannii. Further, we reveal that zinc and copper play distinct roles in macrophage-mediated killing of this pathogen. Collectively, this study supports the targeting of metal ion homeostatic mechanisms as an effective antimicrobial strategy against multi-drug resistant bacterial pathogens.

Suppressive effect of zinc ion on iNOS expression induced by interferon-gamma or tumor necrosis factor-alpha in murine keratinocytes.

PubMed

Yamaoka, J; Kume, T; Akaike, A; Miyachi, Y

2000-05-01

Zinc, an essential metal, is a critical component of zinc binding proteins such as zinc fingers, zinc enzymes and metallothioneins. Recently, evidence for its anti-inflammatory property in skin has been accumulating, as shown in the treatment of acne, alopecia and zinc deficiency. In cutaneous inflammations, a large amount of nitric oxide (NO) is produced through induction of inducible nitric oxide synthase (iNOS) under the influence of proinflammatory cytokines, resulting in tissue damages in skin, as clarified in other organs. Therefore, we asked if the effect of zinc on NO production and/or on iNOS expression in keratinocytes may explain the anti-inflammatory property of zinc in skin. Accordingly, we sought to determine in this study whether zinc ion may have effect on IFN-gamma or TNF-alpha induced NO production and iNOS expression in cultured murine keratinocytes. Ten microM of zinc ion remarkably suppressed cytokine-induced NO production in keratinocytes. Furthermore, zinc ion also suppressed cytokine-induced iNOS expression in the protein level as well as in the messenger RNA level. These results suggest the possibility that the suppressive effect of zinc ion on cytokine-induced NO production in keratinocytes may be in part implicated in the anti-inflammatory property of zinc in some of skin disorders.

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yu; Mei, Xueting; Yuan, Jingquan

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions inmore » serum Zn{sup 2+} and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase{sup +} was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights: • Dissolution of taurine zinc complex can be increased by solid dispersions (SDs). • Taurine zinc SDs blocked doxorubicin-induced hepatotoxicity and cardiotoxicity. • Taurine zinc SDs can alleviate oxidative stress and dampen JNK phosphorylation. • Taurine zinc SDs increased the expression of UGT, HO-1 at mRNA and protein level. • Taurine zinc SDs revealed greater hepatoprotective effects than silymarin.« less

Impact of tire debris on in vitro and in vivo systems

PubMed Central

Gualtieri, Maurizio; Andrioletti, Manuela; Mantecca, Paride; Vismara, Claudio; Camatini, Marina

2005-01-01

Background It is estimated that over 80% of respirable particulate matter (PM10) in cities comes from road transport and that tire and brake wear are responsible for the 3–7% emission of it. Data on the indicators of environmental impact of tire debris (TD), originated from the tire abrasion on roads, are extremely scarce, even though TD contains chemicals (zinc and organic compounds) which can be released in the environment. Methods TD particle morphology was analysed with SEM, TEM and FIB instruments. TD eluates and TD organic extracts were tested at dilution series on human cell lines and Xenopus laevis embryos. 50 and 100 g/L TD were used for the eluates obtained after 24 h at pH 3 and the quantity of zinc present was measured with a ICP-AES. Eluates diluted to 1%, 10%, 50% in culture media and undiluted were used on X. laevis embryos in the FETAX test. HepG2 cells were exposed for 24 h to 0.05 – 50 μg/ml of zinc salt while A549 cells were exposed for 24, 48 and 72 h to 10, 50, 60, or 75 μg/ml of TD extract. X. laevis embryos were exposed to 50, 80, 100, or 120 μg/ml TD extract. Results The solution of undiluted 50 g/L TD produced 80.2% mortality (p < 0.01) in X. laevis embryos and this toxic effect was three times greater than that produced by 100 g/L TD. Zn accumulation in HepG2 cells was evident after 4 h exposure. A549 cells exposed to TD organic extract for 72 h presented a modified morphology, a decrease in cell proliferation and an increase in DNA damage as shown by comet assay. The dose 80 μg/ml of TD extract produced 14.6% mortality in X. laevis embryos and 15.9% mortality at 120 μg/ml. Treatment with 80, 100, or 120 μg/ml TD organic extract increased from 14.8% to 37.8% malformed larvae percentages compared to 5.6% in the control. Conclusion Since the amount of Zn leached from TD is related to pH, aggregation of particles and elution process, the quantity of TD present in the environment has to be taken into account. Moreover the atmospheric conditions, which may deeply influence the particle properties, have to be considered. The TD organic fraction was toxic for cells and organisms. Thus, because of its chemical components, TD may have a potential environmental impact and has to be further investigated. PMID:15813962

Recent advances in zinc-air batteries.

PubMed

Li, Yanguang; Dai, Hongjie

2014-08-07

Zinc-air is a century-old battery technology but has attracted revived interest recently. With larger storage capacity at a fraction of the cost compared to lithium-ion, zinc-air batteries clearly represent one of the most viable future options to powering electric vehicles. However, some technical problems associated with them have yet to be resolved. In this review, we present the fundamentals, challenges and latest exciting advances related to zinc-air research. Detailed discussion will be organized around the individual components of the system - from zinc electrodes, electrolytes, and separators to air electrodes and oxygen electrocatalysts in sequential order for both primary and electrically/mechanically rechargeable types. The detrimental effect of CO2 on battery performance is also emphasized, and possible solutions summarized. Finally, other metal-air batteries are briefly overviewed and compared in favor of zinc-air.

Thermal neutron scintillators using unenriched boron nitride and zinc sulfide

NASA Astrophysics Data System (ADS)

McMillan, J. E.; Cole, A. J.; Kirby, A.; Marsden, E.

2015-06-01

Thermal neutron detectors based on powdered zinc sulfide intimately mixed with a neutron capture compound have a history as long as scintillation technique itself. We show that using unenriched boron nitride powder, rather than the more commonly used enriched lithium fluoride, results in detection screens which produce less light but which are very considerably cheaper. Methods of fabricating large areas of this material are presented. The screens are intended for the production of large area low cost neutron detectors as a replacement for helium-3 proportional tubes.

Chemical analyses of stream sediment in the Tar Creek basin of the Picher mining area, northeast Oklahoma

USGS Publications Warehouse

Parkhurst, David L.; Doughten, Michael; Hearn,, Paul P.

1988-01-01

Chemical analyses are presented for 47 sediment samples from the Tar Creek drainage in the Picher mining area of northeast Oklahoma. The samples were taken in December 1983, June 1984, and June 1985. All of the samples were taken downstream from mine-water discharge points of abandoned lead and zinc mines. The 34 samples taken in December 1983 and June 1984 were analyzed semiquantitatively by emission spectrography for 64 elements and quantitatively for cadmium, copper, iron, manganese, nickel, lead, sulfur, zinc, and organic carbon. The 13 samples taken in June 1985 were analyzed quantitatively for aluminum, cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, phosphorus, lead, sulfur, silicon, titanium, vanadium, zinc, and organic carbon.

Microbial Fuels Cell-Based Biosensor for Toxicity Detection: A Review

PubMed Central

Zhou, Tuoyu; Han, Huawen; Liu, Pu; Xiong, Jian; Tian, Fake; Li, Xiangkai

2017-01-01

With the unprecedented deterioration of environmental quality, rapid recognition of toxic compounds is paramount for performing in situ real-time monitoring. Although several analytical techniques based on electrochemistry or biosensors have been developed for the detection of toxic compounds, most of them are time-consuming, inaccurate, or cumbersome for practical applications. More recently, microbial fuel cell (MFC)-based biosensors have drawn increasing interest due to their sustainability and cost-effectiveness, with applications ranging from the monitoring of anaerobic digestion process parameters (VFA) to water quality detection (e.g., COD, BOD). When a MFC runs under correct conditions, the voltage generated is correlated with the amount of a given substrate. Based on this linear relationship, several studies have demonstrated that MFC-based biosensors could detect heavy metals such as copper, chromium, or zinc, as well as organic compounds, including p-nitrophenol (PNP), formaldehyde and levofloxacin. Both bacterial consortia and single strains can be used to develop MFC-based biosensors. Biosensors with single strains show several advantages over systems integrating bacterial consortia, such as selectivity and stability. One of the limitations of such sensors is that the detection range usually exceeds the actual pollution level. Therefore, improving their sensitivity is the most important for widespread application. Nonetheless, MFC-based biosensors represent a promising approach towards single pollutant detection. PMID:28956857

Microbial Fuels Cell-Based Biosensor for Toxicity Detection: A Review.

PubMed

Zhou, Tuoyu; Han, Huawen; Liu, Pu; Xiong, Jian; Tian, Fake; Li, Xiangkai

2017-09-28

With the unprecedented deterioration of environmental quality, rapid recognition of toxic compounds is paramount for performing in situ real-time monitoring. Although several analytical techniques based on electrochemistry or biosensors have been developed for the detection of toxic compounds, most of them are time-consuming, inaccurate, or cumbersome for practical applications. More recently, microbial fuel cell (MFC)-based biosensors have drawn increasing interest due to their sustainability and cost-effectiveness, with applications ranging from the monitoring of anaerobic digestion process parameters (VFA) to water quality detection (e.g., COD, BOD). When a MFC runs under correct conditions, the voltage generated is correlated with the amount of a given substrate. Based on this linear relationship, several studies have demonstrated that MFC-based biosensors could detect heavy metals such as copper, chromium, or zinc, as well as organic compounds, including p -nitrophenol (PNP), formaldehyde and levofloxacin. Both bacterial consortia and single strains can be used to develop MFC-based biosensors. Biosensors with single strains show several advantages over systems integrating bacterial consortia, such as selectivity and stability. One of the limitations of such sensors is that the detection range usually exceeds the actual pollution level. Therefore, improving their sensitivity is the most important for widespread application. Nonetheless, MFC-based biosensors represent a promising approach towards single pollutant detection.

Synthesis, structure and properties of zinc(II) coordination polymers with 9H-carbazole-2,7-dicarboxylic acid

NASA Astrophysics Data System (ADS)

Yi, Xiu-Chun; Xi, Fu-Gui; Wang, Kun; Su, Zhao; Gao, En-Qing

2013-10-01

From a new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid (2,7-H2CDC), three Zn(II) metal-organic frameworks were synthesized in the absence or presence of ditopic N-donor ligands. They are formulated as [Zn5(μ3-OH)2(2,7-CDC)4(DEF)2] (1) (DEF=N,N-diethylformamide), [Zn2(2,7-CDC)2(DABCO)(H2O)]·5DMF·H2O (2) (DABCO=1-diaza-bicyclo[2.2.2]octane, DMF=N,N-dimethylformamide), and [Zn2(2,7-CDC)2(bpea)]·3DMA·2 H2O (3) (bpea=1,2-bis(4-pyridyl)ethylane, DMA=N,N-dimethylacetamide). Compounds 1 and 3 display the 3D pcu frameworks. In 1 the unusual pentanuclear [Zn5(μ3-OH)2(COO)8] secondary building units (SBUs) are linked by dicarboxylate ligands. Differently, in 3 the well-known paddle-wheel [Zn2(COO)4] SBUs are linked by dicarboxylate and dipyridyl ligands. Compound 2 shows the rare self-catenated 3D alb-3,6-C2/c net topology based on the dinuclear paddle-wheel SBU and a mononuclear unit. The stability and fluorescent properties of the compounds have been studied.

Oral zinc for treating diarrhoea in children

PubMed Central

Lazzerini, Marzia; Wanzira, Humphrey

2016-01-01

Background In developing countries, diarrhoea causes around 500,000 child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF). Objectives To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library 2016, Issue 5), MEDLINE, Embase, LILACS, CINAHL, mRCT, and reference lists up to 30 September 2016. We also contacted researchers. Selection criteria Randomized controlled trials (RCTs) that compared oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery. Data collection and analysis Both review authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. The primary outcomes were diarrhoea duration and severity. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using either a fixed-effect or random-effects model) and assessed heterogeneity. We assessed the certainty of the evidence using the GRADE approach. Main results Thirty-three trials that included 10,841 children met our inclusion criteria. Most included trials were conducted in Asian countries that were at high risk of zinc deficiency. Acute diarrhoea There is currently not enough evidence from well-conducted RCTs to be able to say whether zinc supplementation during acute diarrhoea reduces death or number of children hospitalized (very low certainty evidence). In children older than six months of age, zinc supplementation may shorten the average duration of diarrhoea by around half a day (MD −11.46 hours, 95% CI −19.72 to −3.19; 2581 children, 9 trials, low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, 6 trials, moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (MD −26.39 hours, 95% CI −36.54 to −16.23; 419 children, 5 trials, high certainty evidence). Conversely, in children younger than six months of age, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (MD 5.23 hours, 95% CI −4.00 to 14.45; 1334 children, 2 trials, moderate certainty evidence), or the number of children who still have diarrhoea on day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, 1 trial, moderate certainty evidence). None of the included trials reported serious adverse events. However, zinc supplementation increased the risk of vomiting in both age groups (children greater than six months of age: RR 1.57, 95% CI 1.32 to 1.86; 2605 children, 6 trials, moderate certainty evidence; children less than six months of age: RR 1.54, 95% CI 1.05 to 2.24; 1334 children, 2 trials, moderate certainty evidence). Persistent diarrhoea In children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (MD −15.84 hours, 95% CI −25.43 to −6.24; 529 children, 5 trials, moderate certainty evidence). Authors' conclusions In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency. Oral zinc supplementation for treating diarrhoea in children In low- and middle-income countries, millions of children suffer from severe diarrhoea every year and many die from dehydration. Giving fluids by mouth (using an oral rehydration solution (ORS)) has been shown to save children's lives, but it has no effect on the length of time the children suffer with diarrhoea. Zinc supplementation could help reduce the duration and the severity of diarrhoea, and therefore have an additional benefit over ORS in reducing children mortality. What is oral zinc and how may it shorten the duration and severity of diarrhoea Zinc is usually given as zinc sulphate, zinc acetate, or zinc gluconate, which are all water-soluble compounds. The World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) recommend 10 mg to 20 mg of zinc per day for children with diarrhoea. There are several mechanism of action of zinc on acute diarrhoea, some of which are specific to the gastrointestinal system: zinc restores mucosal barrier integrity and enterocyte brush-border enzyme activity, it promotes the production of antibodies and circulating lymphocytes against intestinal pathogens, and has a direct effect on ion channels, acting as a potassium channel blocker of adenosine 3-5-cyclic monophosphate-mediated chlorine secretion. Cochrane researchers examined the evidence available up to 30 September 2016. What the evidence in the review suggests Thirty-three trials that included 10,841 children met the inclusion criteria of this review. Among children with acute diarrhoea, we don't know if treating children with zinc has an effect on death or number of children hospitalized (very low certainty evidence). In children older than six months, zinc supplementation may shorten the average duration of diarrhoea by around half a day (low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (high certainty evidence). Conversely, in children younger than six months, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (moderate certainty evidence), or the number of children who still have diarrhoea on day seven (moderate certainty evidence). Zinc supplementation increased the risk of vomiting in both age groups (moderate certainty evidence). No other adverse effects were reported. Among children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (moderate certainty) but it probably increases the risk of vomiting (moderate certainty evidence). In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency. PMID:27996088

Chiral mercaptoacetamides display enantioselective inhibition of histone deacetylase 6 and exhibit neuroprotection in cortical neuron models of oxidative stress.

PubMed

Kalin, Jay H; Zhang, Hankun; Gaudrel-Grosay, Sophie; Vistoli, Giulio; Kozikowski, Alan P

2012-03-05

Mercaptoacetamide-based ligands have been designed as a new class of histone deacetylase (HDAC) inhibitors for possible use in the treatment of neurodegenerative diseases. The thiol group of these compounds provides a key binding element for interaction with the catalytic zinc ion, and thus differs from the more typically employed hydroxamic acid based zinc binding groups. Herein we disclose the chemistry and biology of some substituted mercaptoacetamides with the intention of increasing HDAC6 isoform selectivity while maintaining potency similar to their hydroxamic acid analogues. The introduction of a stereocenter α to the thiol group was found to have a considerable impact on HDAC inhibitor potency. These new compounds were also profiled for their therapeutic potential in an in vitro model of stress-induced neuronal injury and were found to act as nontoxic neuroprotective agents. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cancer mortality among workers exposed to zinc chromate paints.

PubMed

Dalager, N A; Mason, T J; Fraumeni, J F; Hoover, R; Payne, W W

1980-01-01

To evaluate the carcinogenicity of chromium compounds among user industries, the proportionate mortality experience of spray painters exposed to zinc chromate primer paints and electroplaters exposed to chromic acid in the aircraft maintenance industry was examined. Compared to the mortality patterns of U.S. white males, no excess of cancer was found in the 48 deaths among electroplaters. Analysis of the 202 deaths among spray painters revealed a significant excess of cancer, primarily of the respiratory tract. The relative increase of respiratory cancer showed a positive gradient with the length of estimated exposure time, and was confined to painters whose interval from first employment to death was at least 20 years. The findings consistent with occupational exposure to chromium compounds, previously shown to be carcinogenic in manufacturing processes, but the effect of other paint constituents, tobacco smoking, or methodologic limitations could not be discounted.

A Stillinger-Weber Potential for InGaN

DOE PAGES

Zhou, X. W.; Jones, R. E.

2017-09-27

Reducing defects in InGaN films deposited on GaN substrates has been critical to fill the “green” gap for solid-state lighting applications. To enable researchers to use molecular dynamics vapor deposition simulations to explores ways to reduce defects in InGaN films, we have developed and characterized a Stillinger-Weber potential for InGaN. We show that this potential reproduces the experimental atomic volume, cohesive energy, and bulk modulus of the equilibrium wurtzite / zinc-blende phases of both InN and GaN. Most importantly, the potential captures the stability of the correct phase of InGaN compounds against a variety of other elemental, alloy, and compoundmore » configurations. Lastly, this is validated by the potential’s ability to predict crystalline growth of stoichiometric wurtzite and zinc-blende In xGa 1-xN compounds during vapor deposition simulations where adatoms are randomly injected to the growth surface.« less

Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action.

PubMed

Wang, Ning; Ivey, Christopher D; Ingersoll, Christopher G; Brumbaugh, William G; Alvarez, David; Hammer, Edward J; Bauer, Candice R; Augspurger, Tom; Raimondo, Sandy; Barnhart, M Christopher

2017-03-01

Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r 2  = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In contrast, the EC50s of fatmucket tested in the single-species study were in the high percentiles (>75th) of species sensitivity distributions for 6 of 7 organic chemicals, indicating mussels might be relatively insensitive to organic chemicals in acute exposures. Environ Toxicol Chem 2017;36:786-796. Published 2016 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

HYPOTHESIS: ZINC CAN BE EFFECTIVE IN TREATMENT OF VITILIGO

PubMed Central

Bagherani, Nooshin; Yaghoobi, Reza; Omidian, Mohammad

2011-01-01

Vitiligo is a common depigmenting skin disorder (prevalence 0.1-2%), still represents a cause of stigmatization and quality of life impairment in a large population. Several theories on vitiligo etiopathogenesis have been suggested including in trauma, stress, and autoimmune and genetic predisposition, accumulation of toxic compounds, altered cellular environment, imbalance in the oxidant-antioxidant system, impaired melanocyte migration and/or proliferation, infection, and psychological factors. Zinc, as a trace element, has many vital functions in human. It is antiapoptotic factor and needed as a cofactor for antioxidant defense system. It plays an important role in the process of melanogenesis. It may be effective in prevention and treatment of vitiligo via some mechanism. Herein, we suggested some probable protective mechanism for zinc in association with vitiligo. PMID:22121258

Tracing of Zinc Nanocrystals in the Anterior Pituitary of Zinc-Deficient Wistar Rats.

PubMed

Kuldeep, Anjana; Nair, Neena; Bedwal, Ranveer Singh

2017-06-01

The aim of this study was to trace zinc nanocrystals in the anterior pituitary of zinc-deficient Wistar rats by using autometallographic technique. Male Wistar rats (30-40 days of age, pre-pubertal period) of 40-50 g body weight were divided into the following: the ZC (zinc control) group-fed with 100 ppm zinc in diet, the ZD (zinc-deficient) group-fed with zinc-deficient (1.00 ppm) diet and the PF (pair-fed) group-received 100 ppm zinc in diet. The experiments were set for 2 and 4 weeks. Pituitary was removed and processed for the autometallographic technique. The control and pair-fed groups retained their normal morphological features. However, male Wistar rats fed on zinc-deficient diet for 2 and 4 weeks displayed a wide range of symptoms such as significant (P < 0.05) decrease in diet consumption, body weight and pituitary weight and decrease in gradation of intensity of zinc nanocrystals in the nuclei. The present findings suggest that the dietary zinc deficiency causes decreased intensity of zinc nanocrystals localization and their distribution in the pituitary thereby contributing to the dysfunction of the pituitary of the male Wistar rats. The severity of zinc deficiency symptoms progressed after the second week of the experiment. Decreased intensity of zinc nanocrystals attenuates the pituitary function which would exert its affect on other endocrine organs impairing their functions indicating that the metabolic regulation of pituitary is mediated to a certain extent by zinc and/or hypothalamus-hypophysial system which also reflects its essentiality during the period of growth.

Fabrication of superhydrophobic surface on zinc substrate by 3-trifluoromethylbenzene diazonium tetrafluoroborate salts

NASA Astrophysics Data System (ADS)

Li, Hong; Huang, Chengya; Zhang, Long; Lou, Wanqiu

2014-09-01

In this study we report a new and efficient method of fabricating superhydrophobic surface on zinc plate modified with 3-trifluoromethylbenzene diazonium tetrafluoroborate salts (CF3BD), which shows a water contact angle of 160° for a 4 μl water droplet and a low sliding angle of about 1°. The morphology and chemical composition of as-prepared superhydrophobic zinc surfaces are investigated by means of scanning electron microscopy (SEM), electron probe microanalyzer (EPMA) and FT-IR spectrum. The results show that the organic layers formed on zinc plate surface are provided with the special hierarchical porous microstructure and the low surface energy, which lead to the superhydrophobicity surface on the modified zinc.

Structure of the Zinc-Bound Amino-Terminal Domain of the NMDA Receptor NR2B Subunit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karakas, E.; Simorowski, N; Furukawa, H

2009-01-01

N-methyl-D-aspartate (NMDA) receptors belong to the family of ionotropic glutamate receptors (iGluRs) that mediate the majority of fast excitatory synaptic transmission in the mammalian brain. One of the hallmarks for the function of NMDA receptors is that their ion channel activity is allosterically regulated by binding of modulator compounds to the extracellular amino-terminal domain (ATD) distinct from the L-glutamate-binding domain. The molecular basis for the ATD-mediated allosteric regulation has been enigmatic because of a complete lack of structural information on NMDA receptor ATDs. Here, we report the crystal structures of ATD from the NR2B NMDA receptor subunit in the zinc-freemore » and zinc-bound states. The structures reveal the overall clamshell-like architecture distinct from the non-NMDA receptor ATDs and molecular determinants for the zinc-binding site, ion-binding sites, and the architecture of the putative phenylethanolamine-binding site.« less

Investigation of the photophysical and photochemical properties of peripherally tetra-substituted water-soluble zwitterionic and cationic zinc(ii) phthalocyanines.

PubMed

Çolak, Senem; Durmuş, Mahmut; Yıldız, Salih Zeki

2016-06-21

In this study, 4-{4-[N-((3-dimethylamino)propyl)amide]phenoxy}phthalonitrile () and its zinc(ii) phthalocyanine derivative () were synthesized for the first time. 4-(N-((3-Dimethylamino)propyl)amide)phenoxy substituted zinc(ii) phthalocyanine () was converted to its water-soluble sulfobetaine (), betaine () and N-oxide () containing zwitterionic and quaternized cationic () derivatives. All newly synthesized compounds () were characterized by the combination of UV-vis, FT-IR, (1)H NMR, mass spectroscopy techniques and elemental analysis. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen quantum yields) properties were investigated in DMSO for all the synthesized zinc(ii) phthalocyanines () and in both DMSO and aqueous solutions for zwitterionic and cationic phthalocyanines () for the specification of their capability as photosensitizers in photodynamic therapy (PDT). The binding behavior of water soluble phthalocyanines () to the bovine serum albumin protein was also examined for the determination of their transportation ability in the blood stream.

Effect of boron compounds on physical, mechanical, and fire properties of injection molded wood plastic composites

Treesearch

Nadir Ayrilmis; Turgay Akbulut; Turker Dundar; Robert H. White; Fatih Mengeloglu; Zeki Candan; Umit Buyuksari; Erkan Avci

2011-01-01

Physical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites (WPCs) incorporated with different levels of boron compounds, borax/boric acid (BX/BA) (0.5:0.5 wt %) and zinc borate (ZB) (4, 8, or 12 wt %) were investigated. The effect of the coupling agent loading (2, 4, or 6 wt %), maleic anhydride-grafted PP (MAPP), on the...

Development and optimization of iron- and zinc-containing nanostructured powders for nutritional applications.

PubMed

Hilty, F M; Teleki, A; Krumeich, F; Büchel, R; Hurrell, R F; Pratsinis, S E; Zimmermann, M B

2009-11-25

Reducing the size of low-solubility iron (Fe)-containing compounds to nanoscale has the potential to improve their bioavailability. Because Fe and zinc (Zn) deficiencies often coexist in populations, combined Fe/Zn-containing nanostructured compounds may be useful for nutritional applications. Such compounds are developed here and their solubility in dilute acid, a reliable indicator of iron bioavailability in humans, and sensory qualities in sensitive food matrices are investigated. Phosphates and oxides of Fe and atomically mixed Fe/Zn-containing (primarily ZnFe2O4) nanostructured powders were produced by flame spray pyrolysis (FSP). Chemical composition and surface area were systematically controlled by varying precursor concentration and feed rate during powder synthesis to increase solubility to the level of ferrous sulfate at maximum Fe and Zn content. Solubility of the nanostructured compounds was dependent on their particle size and crystallinity. The new nanostructured powders produced minimal color changes when added to dairy products containing chocolate or fruit compared to the changes produced when ferrous sulfate or ferrous fumarate were added to these foods. Flame-made Fe- and Fe/Zn-containing nanostructured powders have solubilities comparable to ferrous and Zn sulfate but may produce fewer color changes when added to difficult-to-fortify foods. Thus, these powders are promising for food fortification and other nutritional applications.

Predicted Biological Activity of Purchasable Chemical Space

PubMed Central

2017-01-01

Whereas 400 million distinct compounds are now purchasable within the span of a few weeks, the biological activities of most are unknown. To facilitate access to new chemistry for biology, we have combined the Similarity Ensemble Approach (SEA) with the maximum Tanimoto similarity to the nearest bioactive to predict activity for every commercially available molecule in ZINC. This method, which we label SEA+TC, outperforms both SEA and a naïve-Bayesian classifier via predictive performance on a 5-fold cross-validation of ChEMBL’s bioactivity data set (version 21). Using this method, predictions for over 40% of compounds (>160 million) have either high significance (pSEA ≥ 40), high similarity (ECFP4MaxTc ≥ 0.4), or both, for one or more of 1382 targets well described by ligands in the literature. Using a further 1347 less-well-described targets, we predict activities for an additional 11 million compounds. To gauge whether these predictions are sensible, we investigate 75 predictions for 50 drugs lacking a binding affinity annotation in ChEMBL. The 535 million predictions for over 171 million compounds at 2629 targets are linked to purchasing information and evidence to support each prediction and are freely available via https://zinc15.docking.org and https://files.docking.org. PMID:29193970

Copper(II) and zinc(II) as metal-carboxylate coordination complexes based on (1-methyl-1H-benzo[d]imidazol-2-yl) methanol derivative: Synthesis, crystal structure, spectroscopy, DFT calculations and antioxidant activity

NASA Astrophysics Data System (ADS)

Benhassine, Anfel; Boulebd, Houssem; Anak, Barkahem; Bouraiou, Abdelmalek; Bouacida, Sofiane; Bencharif, Mustapha; Belfaitah, Ali

2018-05-01

This work presents a combined experimental and theoretical study of two new metal-carboxylate coordination compounds. These complexes were prepared from (1-methyl-1H-benzimidazol-2-yl)methanol under mild conditions. The structures of the prepared compounds were characterized by single-crystal X-ray analysis, FTIR and UV-Vis spectroscopy. In the Cupper complex, the Cu(II) ion is coordinated by two ligands, which act as bidentate chelator through the non-substituted N and O atoms, and two carboxylicg oxygen atoms, displaying a hexa-coordinated compound in a distorted octahedral geometry, while in the Zinc complex the ligand is ligated to the Zn(II) ion in monodentate fashion through the N atom, and the metal ion is also bonded to carboxylic oxygen atoms. The tetra-coordinated compound displays a distorted tetrahedral shape. The density functional theory calculations are carried out for the determination of the optimized structures. The electronic transitions and fundamental vibrational wave numbers are calculated and are in good agreement with experimental. In addition, the ligand and its Cu(II) and Zn(II) complexes were screened and evaluated for their potential as DPPH radical scavenger.

Mining Genomes of Marine Cyanobacteria for Elements of Zinc Homeostasis

PubMed Central

Barnett, James P.; Millard, Andrew; Ksibe, Amira Z.; Scanlan, David J.; Schmid, Ralf; Blindauer, Claudia Andrea

2012-01-01

Zinc is a recognized essential element for the majority of organisms, and is indispensable for the correct function of hundreds of enzymes and thousands of regulatory proteins. In aquatic photoautotrophs including cyanobacteria, zinc is thought to be required for carbonic anhydrase and alkaline phosphatase, although there is evidence that at least some carbonic anhydrases can be cambialistic, i.e., are able to acquire in vivo and function with different metal cofactors such as Co2+ and Cd2+. Given the global importance of marine phytoplankton, zinc availability in the oceans is likely to have an impact on both carbon and phosphorus cycles. Zinc concentrations in seawater vary over several orders of magnitude, and in the open oceans adopt a nutrient-like profile. Most studies on zinc handling by cyanobacteria have focused on freshwater strains and zinc toxicity; much less information is available on marine strains and zinc limitation. Several systems for zinc homeostasis have been characterized in the freshwater species Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803, but little is known about zinc requirements or zinc handling by marine species. Comparative metallo-genomics has begun to explore not only the putative zinc proteome, but also specific protein families predicted to have an involvement in zinc homeostasis, including sensors for excess and limitation (SmtB and its homologs as well as Zur), uptake systems (ZnuABC), putative intracellular zinc chaperones (COG0523) and metallothioneins (BmtA), and efflux pumps (ZiaA and its homologs). PMID:22514551

An alternative approach to risk rank chemicals on the threat they pose to the aquatic environment.

PubMed

Johnson, Andrew C; Donnachie, Rachel L; Sumpter, John P; Jürgens, Monika D; Moeckel, Claudia; Pereira, M Gloria

2017-12-01

This work presents a new and unbiased method of risk ranking chemicals based on the threat they pose to the aquatic environment. The study ranked 12 metals, 23 pesticides, 11 other persistent organic pollutants (POPs), 13 pharmaceuticals, 10 surfactants and similar compounds and 2 nanoparticles (total of 71) of concern against one another by comparing their median UK river water and median ecotoxicity effect concentrations. To complement this, by giving an assessment on potential wildlife impacts, risk ranking was also carried out by comparing the lowest 10th percentile of the effects data with the highest 90th percentile of the exposure data. In other words, risk was pared down to just toxicity versus exposure. Further modifications included incorporating bioconcentration factors, using only recent water measurements and excluding either lethal or sub-lethal effects. The top ten chemicals, based on the medians, which emerged as having the highest risk to organisms in UK surface waters using all the ecotoxicity data were copper, aluminium, zinc, ethinylestradiol (EE2), linear alkylbenzene sulfonate (LAS), triclosan, manganese, iron, methomyl and chlorpyrifos. By way of contrast, using current UK environmental quality standards as the comparator to median UK river water concentrations would have selected 6 different chemicals in the top ten. This approach revealed big differences in relative risk; for example, zinc presented a million times greater risk then metoprolol and LAS 550 times greater risk than nanosilver. With the exception of EE2, most pharmaceuticals were ranked as having a relatively low risk. Copyright © 2017 Elsevier B.V. All rights reserved.

Azetidinones as zinc-binding groups to design selective HDAC8 inhibitors.

PubMed

Galletti, Paola; Quintavalla, Arianna; Ventrici, Caterina; Giannini, Giuseppe; Cabri, Walter; Penco, Sergio; Gallo, Grazia; Vincenti, Silvia; Giacomini, Daria

2009-12-01

2-Azetidinones, commonly known as beta-lactams, are well-known heterocyclic compounds. Herein we described the synthesis and biological evaluation of a series of novel beta-lactams. In vitro inhibition assays against HDAC isoforms showed an interesting isoform-selectivity of these compounds towards HDAC6 and HDAC8. The isoform selectivity changed in response to modification of the azetidinone-ring nitrogen atom substituent. The presence of an N-thiomethyl group is a prerequisite for the activity of these compounds in the micromolar range towards HDAC8.

Altered Levels of Zinc and N-methyl-D-aspartic Acid Receptor Underlying Multiple Organ Dysfunctions After Severe Trauma

PubMed Central

Wang, Guanghuan; Yu, Xiaojun; Wang, Dian; Xu, Xiaohu; Chen, Guang; Jiang, Xuewu

2015-01-01

Background Severe trauma can cause secondary multiple organ dysfunction syndrome (MODS) and death. Oxidative stress and/or excitatory neurotoxicity are considered as the final common pathway in nerve cell injuries. Zinc is the cofactor of the redox enzyme, and the effect of the excitatory neurotoxicity is related to N-methyl-D-aspartic acid receptor (NMDAR). Material/Methods We investigated the levels of zinc and brainstem NMDAR in a rabbit model of severe trauma. Zinc and serum biochemical profiles were determined. Immunohistochemistry was used to detect brainstem N-methyl-D-aspartic acid receptor 1 (NR1), N-methyl-D-aspartic acid receptor 2A (NR2A), and N-methyl-D-aspartic acid receptor 2B (NR2B) expression. Results Brain and brainstem Zn levels increased at 12 h, but serum Zn decreased dramatically after the trauma. NR1 in the brainstem dorsal regions increased at 6 h after injury and then decreased. NR2A in the dorsal regions decreased to a plateau at 12 h after trauma. The levels of NR2B were lowest in the death group in the brainstem. Serum zinc was positively correlated with NR2A and 2B and negatively correlated with zinc in the brain. Correlations were also found between the brainstem NR2A and that of the dorsal brainstem, as well as between brainstem NR2A and changes in NR2B. There was a negative correlation between zinc and NR2A. Conclusions Severe trauma led to an acute reduction of zinc enhancing oxidative stress and the changes of NMDAR causing the neurotoxicity of the nerve cells. This may be a mechanism for the occurrence of MODS or death after trauma. PMID:26335029

Stormwater run-off and pollutant transport related to the activities carried out in a modern waste management park.

PubMed

Marques, M; Hogland, W

2001-02-01

Stormwater run-off from twelve different areas and roads has been characterized in a modern waste disposal site, where several waste management activities are carried out. Using nonparametric statistics, medians and confidence intervals of the medians, 22 stormwater quality parameters were calculated. Suspended solids, chemical oxygen demand, biochemical oxygen demand, total nitrogen and total phosphorus, as well as run-off from several areas, showed measured values above standard limits for discharge into recipient waters--even higher than those of leachate from covered landfill cells. Of the heavy metals analyzed, copper, zinc and nickel were the most prevalent, being detected in every sample. Higher concentrations of metals such as zinc, nickel, cobalt, iron and cadmium were found in run-off from composting areas, compared to areas containing stored and exposed scrap metal. This suggests that factors other than the total amount of exposed material affect the concentration of metals in run-off, such as binding to organic compounds and hydrological transport efficiency. The pollutants transported by stormwater represent a significant environmental threat, comparable to leachate. Careful design, monitoring and maintenance of stormwater run-off drainage systems and infiltration elements are needed if infiltration is to be used as an on-site treatment strategy.

Targeting histone deacetylases: perspectives for epigenetic-based therapy in cardio-cerebrovascular disease

PubMed Central

Wang, Zi-Ying; Qin, Wen; Yi, Fan

2015-01-01

Although the pathogenesis of cardio-cerebrovascular disease (CCVD) is multifactorial, an increasing number of experimental and clinical studies have highlighted the importance of histone deacetylase (HDAC)-mediated epigenetic processes in the development of cardio-cerebrovascular injury. HDACs are a family of enzymes to balance the acetylation activities of histone acetyltransferases on chromatin remodeling and play essential roles in regulating gene transcription. To date, 18 mammalian HDACs are identified and grouped into four classes based on similarity to yeast orthologs. The zinc-dependent HDAC family currently consists of 11 members divided into three classes (class I, II, and IV) on the basis of structure, sequence homology, and domain organization. In comparison, class III HDACs (also known as the sirtuins) are composed of a family of NAD+-dependent protein-modifying enzymes related to the Sir2 gene. HDAC inhibitors are a group of compounds that block HDAC activities typically by binding to the zinc-containing catalytic domain of HDACs and have displayed anti-inflammatory and antifibrotic effects in the cardio-cerebrovascular system. In this review, we summarize the current knowledge about classifications, functions of HDACs and their roles and regulatory mechanisms in the cardio-cerebrovascular system. Pharmacological targeting of HDAC-mediated epigenetic processes may open new therapeutic avenues for the treatment of CCVD. PMID:25870619

Facile fabrication and characterization of chitosan-based zinc oxide nanoparticles and evaluation of their antimicrobial and antibiofilm activity

NASA Astrophysics Data System (ADS)

Dhillon, Gurpreet Singh; Kaur, Surinder; Brar, Satinder Kaur

2014-06-01

The present investigation deals with the facile synthesis and characterization of chitosan (CTS)-based zinc oxide (ZnO) nanoparticles (NPs) and their antimicrobial activities against pathogenic microorganisms. ZnO-CTS NPs were synthesized through two different methods: nano spray drying and precipitation, using various organic compounds (citric acid, glycerol, starch and whey powder) as stabilizers. Both the synthesis methods were simple and were devoid of any chemical usage. The detailed characterization of the NPs was carried out using UV-Vis spectroscopy, dynamic light scattering particle size analysis, zeta potential measurements and scanning electron microscopy, which confirmed the fabrication of NPs with different shapes and sizes. Antimicrobial assay of synthesized ZnO-CTS NPs was carried out against different pathogenic microbial strains ( Candida albicans, Micrococcus luteus and Staphylococcus aureus). The significant ( p < 0.05) inhibition of growth was observed for both M. luteus and S. aureus with ZnO-CTS NPs (with a concentration ranging from 0.625 to 0.156 mg/ml) as compared to control treatment. ZnO-CTS NPs also showed significant biofilm inhibition activity ( p < 0.05) against M. luteus and S. aureus. The study demonstrated the potential of ZnO-CTS NPs as antimicrobial and antibiofilm agents.

Comparison of proteome response to saline and zinc stress in lettuce

PubMed Central

Lucini, Luigi; Bernardo, Letizia

2015-01-01

Zinc salts occurring in soils can exert an osmotic stress toward plants. However, being zinc a heavy metal, some more specific effects on plant metabolisms can be forecast. In this work, lettuce has been used as a model to investigate salt and zinc stresses at proteome level through a shotgun tandem MS proteomic approach. The effect of zinc stress in lettuce, in comparison with NaCl stress, was evaluated to dissect between osmotic/oxidative stress related effects, from those changes specifically related to zinc. The analysis of proteins exhibiting a fold change of 3 as minimum (on log 2 normalized abundances), revealed the involvement of photosynthesis (via stimulation of chlorophyll synthesis and enhanced role of photosystem I) as well as stimulation of photophosphorylation. Increased glycolytic supply of energy substrates and ammonium assimilation [through formation of glutamine synthetase (GS)] were also induced by zinc in soil. Similarly, protein metabolism (at both transcriptional and ribosomal level), heat shock proteins, and proteolysis were affected. According to their biosynthetic enzymes, hormones appear to be altered by both the treatment and the time point considered: ethylene biosynthesis was enhanced, while production of abscisic acid was up-regulated at the earlier time point to decrease markedly and gibberellins were decreased at the later one. Besides aquaporin PIP2 synthesis, other osmotic/oxidative stress related compounds were enhanced under zinc stress, i.e., proline, hydroxycinnamic acids, ascorbate, sesquiterpene lactones, and terpenoids biosynthesis. Although the proteins involved in the response to zinc stress and to salinity were substantially the same, their abundance changed between the two treatments. Lettuce response to zinc was more prominent at the first sampling point, yet showing a faster adaptation than under NaCl stress. Indeed, lettuce plants showed an adaptation after 30 days of stress, in a more pronounced way in the case of zinc. PMID:25932029

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats.

PubMed

Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague-Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn(2+) and albumin levels (P<0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P<0.01). qBase(+) was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P<0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of Different Zinc Species on Cellar Zinc Distribution, Cell Cycle, Apoptosis and Viability in MDAMB231 Cells.

PubMed

Wang, Yan-hong; Zhao, Wen-jie; Zheng, Wei-juan; Mao, Li; Lian, Hong-zhen; Hu, Xin; Hua, Zi-chun

2016-03-01

Intracellular metal elements exist in mammalian cells with the concentration range from picomoles per litre to micromoles per litre and play a considerable role in various biological procedures. Element provided by different species can influence the availability and distribution of the element in a cell and could lead to different biological effects on the cell's growth and function. Zinc as an abundant and widely distributed essential trace element, is involved in numerous and relevant physiological functions. Zinc homeostasis in cells, which is regulated by metallothioneins, zinc transporter/SLC30A, Zrt-/Irt-like proteins/SLC39A and metal-response element-binding transcription factor-1 (MTF-1), is crucial for normal cellular functioning. In this study, we investigated the influences of different zinc species, zinc sulphate, zinc gluconate and bacitracin zinc, which represented inorganic, organic and biological zinc species, respectively, on cell cycle, viability and apoptosis in MDAMB231 cells. It was found that the responses of cell cycle, apoptosis and death to different zinc species in MDAMB231 cells are different. Western blot analysis of the expression of several key proteins in regulating zinc-related transcription, cell cycle, apoptosis, including MTF-1, cyclin B1, cyclin D1, caspase-8 and caspase-9 in treated cells further confirmed the observed results on cell level.

Fabrication and test of inorganic/organic separators. [for silver zinc batteries

NASA Technical Reports Server (NTRS)

Smatko, J. S.

1974-01-01

Completion of testing and failure analysis of MDC 40 Ahr silver zinc cells containing largely inorganic separators was accomplished. The results showed that the wet stand and cycle life objectives of the silver zinc cell development program were accomplished. Building, testing and failure analysis of two plate cells employing three optimum separators selected on the basis of extensive screening tests, was performed. The best separator material as a result of these tests was doped calcium zirconate.

Organic Compounds and Trace Elements in Fish Tissue and Bed Sediment in the Delaware River Basin, New Jersey, Pennsylvania, New York, and Delaware, 1998-2000

USGS Publications Warehouse

Romanok, Kristin M.; Fischer, Jeffrey M.; Riva-Murray, Karen; Brightbill, Robin; Bilger, Michael

2006-01-01

As part of the National Water-Quality Assessment (NAWQA) program activities in the Delaware River Basin (DELR), samples of fish tissue from 21 sites and samples of bed sediment from 35 sites were analyzed for a suite of organic compounds and trace elements. The sampling sites, within subbasins ranging in size from 11 to 600 square miles, were selected to represent 5 main land-use categories in the DELR -forest, low-agricultural, agricultural, urban, and mixed use. Samples of both fish tissue and bed sediment were also collected from 4 'large-river' sites that represented drainage areas ranging from 1,300 to 6,800 square miles, areas in which the land is used for a variety of purposes. One or more of the organochlorine compounds-DDT and chlordane metabolites, polychlorinated biphenyls (total PCBs), and dieldrin- were detected frequently in samples collected over a wide geographic area. One or more of these compounds were detected in fish-tissue samples from 92 percent of the sites and in bed-sediment samples from 82 percent of the sites. Concentrations of total DDT, total chlordanes, total PCBs, and dieldrin in whole white suckers and in bed sediment were significantly related to urban/industrial basin characteristics, such as percentage of urban land use and population density. Semi-volatile organic compounds (SVOCs)-total polycyclic aromatic hydrocarbons (PAHs), total phthalates, and phenols- were detected frequently in bed-sediment samples. All three types of SVOCs were detected in samples from at least one site in each land-use category. The highest detection rates and concentrations typically were in samples from sites in the urban and mixed land-use categories, as well as from the large-river sites. Concentrations of total PAHs and total phthalates in bed-sediment samples were found to be statistically related to percentages of urban land use and to population density in the drainage areas represented by the sampling sites. The samples of fish tissue and bed sediment collected throughout the DELR were analyzed for a large suite of trace elements, but results of the analyses for eight elements-arsenic, cadmium, chromium, copper, lead, nickel, mercury, and zinc- that are considered contaminants of concern are described in this report. One or more of the eight trace elements were detected in samples from every fish tissue and bed-sediment sampling site, and all of the trace elements were detected in samples from 97 percent of the bed-sediment sites. The concentrations of organic compounds and trace elements in the DELR samples were compared to applicable guidelines for the protection of wildlife and other biological organisms. Concentrations of total DDT, total chlordanes, total PCBs, and dieldrin in fish-tissue samples from 14 sites exceeded one or more of the Wildlife Protective Guidelines established by the New York State Department of Environmental Conservation. Concentrations of one or more organic compounds in samples from 16 bed-sediment sites exceeded the Threshold Effects Concentrations (TEC) of the Canadian Sediment Quality Guidelines, and concentrations of one or more of the eight trace elements in samples from 38 bed-sediment sites exceeded the TEC. (The TEC is the concentration below which adverse biological effects in freshwater ecosystems are expected to be rare.) Concentrations of organic compounds in samples from some bed-sediment sites exceeded the Canadian Probable Effects Concentrations (PEC), and concentrations of trace elements in samples from 18 sites exceeded the PEC. (The PEC is the concentration above which adverse effects to biological organisms are expected to occur frequently). Concentrations of organic compounds and trace elements in samples from the DELR were compared to similar data from other NAWQA study units in the northeastern United States and also data from the Mobile River (Alabama) Basin and the Northern Rockies Intermontane Basin study units. Median concentrations of to

Short-term effect of strontium- and zinc-containing toothpastes and mouthrinses on volatile sulphur compounds in morning breath: a randomized, double-blind, cross-over clinical study.

PubMed

Soares, Léo G; Jonski, Grazyna; Tinoco, Eduardo M B; Young, Alix

2015-04-01

Zinc (Zn) reduces the formation of volatile sulphur compounds (VSCs) associated with oral malodour. Although strontium (Sr) is included in some products for reducing dental hypersensitivity, it may also have anti-halitosis properties. This randomized, double-blind, cross-over clinical study compared the anti-VSC effect of brushing with commercial toothpastes and rinses containing Zn and Sr. The volunteers (n = 30) either brushed/rinsed with/without tongue brushing using Zn-containing toothpaste/rinse, Sr-containing toothpaste/rinse, or placebo (control). Volatile sulphur compounds [hydrogen sulphide (H2 S) and methyl mercaptan (CH3 SH)] were measured, in morning breath, using gas chromatography. The anti-VSC effects of the test toothpastes and test rinses were significantly better than the anti-VSC effects of the respective controls. Toothbrushing with test toothpastes gave median reductions, compared with the control, of 70% for H2 S and 55-57% for CH3 SH. Rinsing with the Sr- and Zn-containing solutions had the same anti-VSC effect as toothbrushing and tooth- and tongue brushing with the Sr- and Zn-containing toothpastes. Zinc-containing rinse resulted in a significantly higher median salivary level of Zn compared with brushing with Zn-containing toothpaste, although this effect did not correlate with the anti-VSC effect. It can be concluded that the Sr- and Zn-containing toothpastes and the Zn- and Sr-containing rinses, when used in the evening, are equally effective in reducing morning-breath VSCs the following day. © 2015 Eur J Oral Sci.

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles.

PubMed

Vollenweider, Pierre; Bernasconi, Petra; Gautschi, Hans-Peter; Menard, Terry; Frey, Beat; Günthardt-Goerg, Madeleine S

2011-01-01

The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing β-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. Copyright © 2010 Elsevier Ltd. All rights reserved.

AUTOMATED RESPIROMETER METHOD FOR MICROBIAL TOXICITY ASSESSMENT OF LOW-LEVEL ZINC CONTAMINATION IN SOIL

EPA Science Inventory

Zinc is an essential trace element for all living organisms including humans. ecause microbial-based toxicity approaches to assess the changes in ecosystem processes are not well defined for soil application, this laboratory has developed an automated respirometer capable of meas...

DOSE-DEPENDENT TRANSITIONS IN MECHANISMS OF TOXICITY: ZINC CASE EXAMPLE

EPA Science Inventory

Zinc (Zn) is an essential trace element. Maternal Zn deficiency can result in complications of pregnancy and inadequate supply of Zn to the conceptus can interfere with the development of numerous organ systems. Maternal dietary Zn deficiency has been shown to be teratogenic in a...

Chronic zinc deficiency alters chick gut microbiota composition and function

USDA-ARS?s Scientific Manuscript database

Zinc (Zn) deficiency is a prevalent micronutrient insufficiency. Although the gut is a vital organ for Zn utilization, and Zn deficiency is associated with impaired intestinal permeability and a global decrease in gastrointestinal health, alterations in the gut microbial ecology of the host under co...

Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators.

PubMed

Fukuzumi, Shunichi; Ohkubo, Kei; Zheng, Xiang; Chen, Yihui; Pandey, Ravindra K; Zhan, Riqiang; Kadish, Karl M

2008-03-06

A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile).

Synthesis aspects, structural, spectroscopic, antimicrobial and room temperature ferromagnetism of zinc iodide complex with Schiff based ligand.

PubMed

Shakila, K; Kalainathan, S

2015-01-25

In this paper, we report the successful growth of complex compound of zinc iodide with thiocarbamide by slow evaporation method. The single crystal XRD study reveals that the crystal belongs to monoclinic system with centrosymmetric space group and powder XRD analysis shows that the perfect crystalline nature of the crystal. The presence of functional group and element were confirmed from FT-IR and EDAX analysis. Optical absorbance of the grown crystal was studied by UV-Vis spectrophotometer. The optical constants were calculated from the optical absorbance data such as refractive index (n), extinction coefficient (K) and reflectance (R). The optical band gap (Eg) of thiocarbamide zinc iodide crystal is 4.22 eV. The magnetic properties of grown crystal have been determined by Vibrating Sample Magnetometry (VSM). Room temperature magnetization revealed a ferromagnetic behaviour for the grown crystal. The antibacterial and antifungal activities of the title compound were performed by well diffusion method and MIC method against the standard bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and against fungus like Aspergillus niger, Rhizopus sps and Penicillium sps. Thermal behaviour of the crystal has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Copyright © 2014. Published by Elsevier B.V.

Maternal dietary zinc supplementation enhances the epigenetic-activated antioxidant ability of chick embryos from maternal normal and high temperatures.

PubMed

Zhu, Yongwen; Liao, Xiudong; Lu, Lin; Li, Wenxiang; Zhang, Liyang; Ji, Cheng; Lin, Xi; Liu, Hsiao-Ching; Odle, Jack; Luo, Xugang

2017-03-21

The role of maternal dietary zinc supplementation in protecting the embryos from maternal hyperthermia-induced negative effects via epigenetic mechanisms was examined using an avian model (Gallus gallus). Broiler breeder hens were exposed to two maternal temperatures (21°C and 32°C) × three maternal dietary zinc treatments (zinc-unsupplemented control diet, the control diet + 110 mg zinc/kg inorganic or organic zinc) for 8 weeks. Maternal hyperthermia increased the embryonic mortality and induced oxidative damage evidenced by the elevated mRNA expressions of heat shock protein genes. Maternal dietary zinc deficiency damaged the embryonic development associated with the global DNA hypomethylation and histone 3 lysine 9 hyperacetylation in the embryonic liver. Supplementation of zinc in maternal diets effectively eliminated the embryonic mortality induced by maternal hyperthermia and enhanced antioxidant ability with the increased mRNA and protein expressions of metallothionein IV in the embryonic liver. The increased metallothionein IV mRNA expression was due to the reduced DNA methylation and increased histone 3 lysine 9 acetylation of the metallothionein IV promoter regardless of zinc source. These data demonstrate that maternal dietary zinc addition as an epigenetic modifier could protect the offspring embryonic development against maternal heat stress via enhancing the epigenetic-activated antioxidant ability.

Syntheses, structures and luminescence for zinc coordination polymers based on a multifunctional 4‧-(3-carboxyphenyl)- 3,2‧:6‧,3″-terpyridine ligand

NASA Astrophysics Data System (ADS)

Cheng, Yue; Yang, Meng-Lin; Hu, Huai-Ming; Xu, Bing; Wang, Xiaofang; Xue, Ganglin

2016-07-01

Six new coordination polymers, [ZnLCl]n(1), [ZnL2]n·2nH2O (2), [Zn2L(o-bdc)(OH)]n·0.5nH2O (3), [Zn2L(m-bdc)(OH)]n·nH2O (4), [Zn2L2(p-bdc) (H2O)2]n·nH2O (5), [Zn2L(1,2,4-btc)(H2O)]n(6), (HL=4‧-(3-carboxyphenyl)- 3,2‧:6‧,3″-terpyridine, H2(o-bdc)= benzene-1,2-dicarboxylic acid, H2(m-bdc)= benzene-1,3-dicarboxylic acid, H2(p-bdc)= benzene-1,4-dicarboxylic acid, H3(1,2,4-btc)= benzene-1,2,4-tricarboxylic acid) have been synthesized under the hydrothermal conditions. Compound 1 displays a 3-connected 2D network structure with point symbol of {82.10}. Compound 2 exhibits 1D infinite loop chain structure. Compound 3 possesses a (3,8)-connected 3D framework composed of tetranuclear units with point symbol of {43}2{46.618.84}. Compound 4 features a typical 2D hcb network based on tetranuclear zinc(II) units with point symbol of {44.62}. Compound 5 presents a classical two-fold penetration sql network with point symbol of {63}. Compound 6 can be seen as a (3,3,6)-connected 3D net with point symbol of {42.64.89}{42.6}{63}. The thermal stability and luminescent properties of compounds 1-6 in the solid state are discussed in detail.

T-screen and yeast assay for the detection of the thyroid-disrupting activities of cadmium, mercury, and zinc.

PubMed

Li, Jian; Liu, Yun; Kong, Dongdong; Ren, Shujuan; Li, Na

2016-05-01

In the present study, a two-hybrid yeast bioassay and a T-screen were used to screen for the thyroid receptor (TR)-disrupting activity of select metallic compounds (CdCl2, ZnCl2, HgCl2, CuSO4, MnSO4, and MgSO4). The results reveal that none of the tested metallic compounds showed TR-agonistic activity, whereas ZnCl2, HgCl2, and CdCl2 demonstrated TR antagonism. For the yeast assay, the dose-response relationship of these metallic compounds was established, and the concentrations producing 20 % of the maximum effect of ZnCl2, HgCl2, and CdCl2 were 9.1 × 10(-5), 3.2 × 10(-6), and 1.2 × 10(-6) mol/L, respectively. The T-screen also supported the finding that ZnCl2, HgCl2, and CdCl2 decreased the cell proliferation at concentrations ranging from 10(-6) to 10(-4) mol/L. Furthermore, the thyroid-disrupting activity of metallic compounds in environmental water samples collected from the Guanting Reservoir, Beijing, China was evaluated. Solid-phase extraction was used to separate the organic extracts, and a modified two-hybrid yeast bioassay revealed that the metallic compounds in the water samples could affect thyroid hormone-induced signaling by decreasing the binding of the thyroid hormone. The addition of ethylenediaminetetraacetic acid (30 mg/L) could eliminate the effects. Thus, the cause(s) of the thyroid toxicity in the water samples appeared to be partly related to the metallic compounds.

Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

PubMed

Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

2018-01-01

Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

Comprehensive analysis of organic ligands in whole root exudates using nuclear magnetic resonance and gas chromatography-mass spectrometry.

PubMed

Fan, T W; Lane, A N; Pedler, J; Crowley, D; Higashi, R M

1997-08-15

Root exudates in the rhizosphere are vital to the normal life cycle of plants. A key factor is phytometallophores, which function in the nutritional acquisition of iron and zinc and are likely to be important in the uptake of pollutant metals by plants. Unraveling the biochemistry of these compounds is tedious using traditional analyses, which also fall short in providing the overall chemical composition or in detecting unknown or unexpected organic ligands in the exudates. Here, we demonstrate a comprehensive analysis of the exudate composition directly by 1H and 13C multidimensional NMR and silylation GC-MS. The advantages are (a) minimal sample preparation, with no loss of unknown compounds, and reduced net analysis time; (b) structure-based analysis for universal detection and identification; and (c) simultaneous analysis of a large number of constituents in a complex mixture. Using barley root exudates, a large number of common organic and amino acids were identified. Three derivatives of mugineic acid phytosiderophores were also determined, the major one being 3-epihydroxymugineic acid, for which complete 1H and 13C NMR assignments were obtained. Quantification of all major components using these methods revealed a sevenfold increase in total exudation under moderate iron deficiency, with 3-epihydroxymugineic acid comprising approximately 22% of the exudate mixture. As iron deficiency increased, total quantities of exudate per gram of root remained unchanged, but the relative quantity of carbon allocated to phytosiderophore increased to approximately 50% of the total exudate in response to severe iron deficiency.

Effects of natural organic matter properties on the dissolution kinetics of zinc oxide nanoparticles

USGS Publications Warehouse

Jiang, Chuanjia; Aiken, George R.; Hsu-Kim, Heileen

2015-01-01

The dissolution of zinc oxide (ZnO) nanoparticles (NPs) is a key step of controlling their environmental fate, bioavailability, and toxicity. Rates of dissolution often depend upon factors such as interactions of NPs with natural organic matter (NOM). We examined the effects of 16 different NOM isolates on the dissolution kinetics of ZnO NPs in buffered potassium chloride solution using anodic stripping voltammetry to directly measure dissolved zinc concentrations. The observed dissolution rate constants (kobs) and dissolved zinc concentrations at equilibrium increased linearly with NOM concentration (from 0 to 40 mg C L–1) for Suwannee River humic and fulvic acids and Pony Lake fulvic acid. When dissolution rates were compared for the 16 NOM isolates, kobs was positively correlated with certain properties of NOM, including specific ultraviolet absorbance (SUVA), aromatic and carbonyl carbon contents, and molecular weight. Dissolution rate constants were negatively correlated to hydrogen/carbon ratio and aliphatic carbon content. The observed correlations indicate that aromatic carbon content is a key factor in determining the rate of NOM-promoted dissolution of ZnO NPs. The findings of this study facilitate a better understanding of the fate of ZnO NPs in organic-rich aquatic environments and highlight SUVA as a facile and useful indicator of NOM interactions with metal-based nanoparticles.

Preparation of organic and water hydrogen for stable isotope analysis. Effects due to reaction vessels and zinc reagent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schimmelmann, A.; DeNiro, M.J.

1993-03-15

Combustion of organic matter in sealed Pyrex, Vycor, and quartz ampules at temperatures between 520 and 900[degrees]C yields less than stoichiometric amounts of water. The loss of hydrogen to hydration reactions between water vapor and glass/quartz interferes with the determination of C/H and N/H elemental ratios in organic matter. The effect increases from quartz to Vycor to Pyrex, but the incomplete yield does not significantly affect the precision and accuracy of the determination of stable hydrogen isotope ratios. Reactions between water and Pyrex do not affect the conversion of water to hydrogen with zinc in Pyrex ampules at 500[degrees]C, whichmore » is quantitative, but even preoutgassed zinc contains a deuterium-depleted hydrogen blank. D/H ratios in hydrogen from the Zn method require a nonlinear correction to achieve compatibility with [delta]D values from the uranium method. 19 refs., 4 tabs.« less

A multiscale approach to simulating the conformational properties of unbound multi-C₂H₂ zinc finger proteins.

PubMed

Liu, Lei; Wade, Rebecca C; Heermann, Dieter W

2015-09-01

The conformational properties of unbound multi-Cys2 His2 (mC2H2) zinc finger proteins, in which zinc finger domains are connected by flexible linkers, are studied by a multiscale approach. Three methods on different length scales are utilized. First, atomic detail molecular dynamics simulations of one zinc finger and its adjacent flexible linker confirmed that the zinc finger is more rigid than the flexible linker. Second, the end-to-end distance distributions of mC2H2 zinc finger proteins are computed using an efficient atomistic pivoting algorithm, which only takes excluded volume interactions into consideration. The end-to-end distance distribution gradually changes its profile, from left-tailed to right-tailed, as the number of zinc fingers increases. This is explained by using a worm-like chain model. For proteins of a few zinc fingers, an effective bending constraint favors an extended conformation. Only for proteins containing more than nine zinc fingers, is a somewhat compacted conformation preferred. Third, a mesoscale model is modified to study both the local and the global conformational properties of multi-C2H2 zinc finger proteins. Simulations of the CCCTC-binding factor (CTCF), an important mC2H2 zinc finger protein for genome spatial organization, are presented. © 2015 Wiley Periodicals, Inc.

Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

PubMed

Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

2012-01-17

Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions. © 2011 American Chemical Society

Biocatalytic trifluoromethylation of unprotected phenols

PubMed Central

Simon, Robert C.; Busto, Eduardo; Richter, Nina; Resch, Verena; Houk, Kendall N.; Kroutil, Wolfgang

2016-01-01

Organofluorine compounds have become important building blocks for a broad range of advanced materials, polymers, agrochemicals, and increasingly for pharmaceuticals. Despite tremendous progress within the area of fluorination chemistry, methods for the direct introduction of fluoroalkyl-groups into organic molecules without prefunctionalization are still highly desired. Here we present a concept for the introduction of the trifluoromethyl group into unprotected phenols by employing a biocatalyst (laccase), tBuOOH, and either the Langlois' reagent or Baran's zinc sulfinate. The method relies on the recombination of two radical species, namely, the phenol radical cation generated directly by the laccase and the CF3-radical. Various functional groups such as ketone, ester, aldehyde, ether and nitrile are tolerated. This laccase-catalysed trifluoromethylation proceeds under mild conditions and allows accessing trifluoromethyl-substituted phenols that were not available by classical methods. PMID:27834376

Development of a space stable thermal control coatings for use in large space vehicles

NASA Technical Reports Server (NTRS)

Gilligan, J. E.; Ashford, N. A.; Harada, Y.; Leas, R. M.

1971-01-01

The preparation and evaluation of zinc orthotitanate and of several new pigments and the environmental testing and evaluation of these pigments and of coatings made from them constitute the bulk of the work accomplished. New pigments were prepared and EPR spectra of pigments and their precursor compounds studied. Results of extensive testing of commercially-available, strippable, protective coatings are reported; Owens-Illinois 650 glass resin has been stabilized against progressive mechanical failures; and definite improvements have been noted. A zinc oxide pigmented lithium silicate paint has demonstrated very good ultraviolet stability.

Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09

USGS Publications Warehouse

Wilson, Jennifer T.

2011-01-01

Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (TEC) and probable effect concentration (PEC). Trace element concentrations were greater than the TEC in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the TEC in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively large ranges and standard deviations associated with the concentrations measured in all three areas, the trace element concentrations are similar. On the basis of Mann-Whitney U test results, the presence of a military installation in a watershed was associated with statistically significant higher chromium, mercury, and zinc concentrations in streambed sediments compared to concentrations of the same elements in a watershed without a military installation. Halogenated organic compounds analyzed in sediment samples included pesticides (chlordane, dieldrin, DDT, DDD, and DDE), polychlorinated biphenyls (PCBs), and brominated flame retardants. Three or more halogenated organic compounds were detected in each sediment sample, and 66 percent of all concentrations were less than the respective interim reporting levels. Halogenated organic compound concentrations were mostly low compared to consensus-based sediment quality guidelines-;TECs were exceeded in 11 percent of the analyses and PECs were exceeded in 1 percent of the analyses. Chlordane compounds were the most frequently detected halogenated organic compounds with one or more detections of chlordane compounds in every watershed; concentrations were greater than the TEC in 6 percent of the samples. Dieldrin was detected in 50 percent of all samples, however all concentrations were much less than the TEC. The DDT compounds (p,p'-DDT, p,p'-DDD, and p,p'-DDE) were detected less frequently than some other halogenated organic compounds, however most detections exceeded the TECs. p,p'-DDT was detected in 13 percent of the samples (TEC exceeded in 67 percent); p,p'-DDD was detected in 19 percent of the samples (TEC exceeded in 78 percent); and p,p'-DDE was detected in 35 percent of the samples (TEC exceeded in 53 percent). p,p'-DDE concentrations in streambed-sediment samples correlate positively with population density and residential, commercial, and transportation land use. One or more PCB congeners were detected in

Induction of Syndecan-4 by Organic-Inorganic Hybrid Molecules with a 1,10-Phenanthroline Structure in Cultured Vascular Endothelial Cells.

PubMed

Hara, Takato; Kojima, Takayuki; Matsuzaki, Hiroka; Nakamura, Takehiro; Yoshida, Eiko; Fujiwara, Yasuyuki; Yamamoto, Chika; Saito, Shinichi; Kaji, Toshiyuki

2017-02-08

Organic-inorganic hybrid molecules constitute analytical tools used in biological systems. Vascular endothelial cells synthesize and secrete proteoglycans, which are macromolecules consisting of a core protein and glycosaminoglycan side chains. Although the expression of endothelial proteoglycans is regulated by several cytokines/growth factors, there may be alternative pathways for proteoglycan synthesis aside from downstream pathways activated by these cytokines/growth factors. Here, we investigated organic-inorganic hybrid molecules to determine a variant capable of analyzing the expression of syndecan-4, a transmembrane heparan-sulfate proteoglycan, and identified 1,10-phenanthroline ( o -Phen) with or without zinc (Zn-Phen) or rhodium (Rh-Phen). Bovine aortic endothelial cells in culture were treated with these compounds, and the expression of syndecan-4 mRNA and core proteins was determined by real-time reverse transcription polymerase chain reaction and Western blot analysis, respectively. Our findings indicated that o -Phen and Zn-Phen specifically and strongly induced syndecan-4 expression in cultured vascular endothelial cells through activation of the hypoxia-inducible factor-1α/β pathway via inhibition of prolyl hydroxylase-domain-containing protein 2. These results demonstrated an alternative pathway involved in mediating induction of endothelial syndecan-4 expression and revealed organic-inorganic hybrid molecules as effective tools for analyzing biological systems.

Estimating the Global Prevalence of Inadequate Zinc Intake from National Food Balance Sheets: Effects of Methodological Assumptions

PubMed Central

Wessells, K. Ryan; Singh, Gitanjali M.; Brown, Kenneth H.

2012-01-01

Background The prevalence of inadequate zinc intake in a population can be estimated by comparing the zinc content of the food supply with the population’s theoretical requirement for zinc. However, assumptions regarding the nutrient composition of foods, zinc requirements, and zinc absorption may affect prevalence estimates. These analyses were conducted to: (1) evaluate the effect of varying methodological assumptions on country-specific estimates of the prevalence of dietary zinc inadequacy and (2) generate a model considered to provide the best estimates. Methodology and Principal Findings National food balance data were obtained from the Food and Agriculture Organization of the United Nations. Zinc and phytate contents of these foods were estimated from three nutrient composition databases. Zinc absorption was predicted using a mathematical model (Miller equation). Theoretical mean daily per capita physiological and dietary requirements for zinc were calculated using recommendations from the Food and Nutrition Board of the Institute of Medicine and the International Zinc Nutrition Consultative Group. The estimated global prevalence of inadequate zinc intake varied between 12–66%, depending on which methodological assumptions were applied. However, country-specific rank order of the estimated prevalence of inadequate intake was conserved across all models (r = 0.57–0.99, P<0.01). A “best-estimate” model, comprised of zinc and phytate data from a composite nutrient database and IZiNCG physiological requirements for absorbed zinc, estimated the global prevalence of inadequate zinc intake to be 17.3%. Conclusions and Significance Given the multiple sources of uncertainty in this method, caution must be taken in the interpretation of the estimated prevalence figures. However, the results of all models indicate that inadequate zinc intake may be fairly common globally. Inferences regarding the relative likelihood of zinc deficiency as a public health problem in different countries can be drawn based on the country-specific rank order of estimated prevalence of inadequate zinc intake. PMID:23209781

Trace elements and organic compounds in streambed sediment and fish tissue of coastal New England streams, 1998-99

USGS Publications Warehouse

Chalmers, Ann

2002-01-01

Streambed sediment and fish tissue were collected at 14 river sites in eastern New England during low-flow conditions in 1998 and 1999 as part of the New England Coastal Basins (NECB) study of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Sampling sites were selected over a range of urban settings. Population densities at selected sites ranged from 26 to 3,585 people per square mile, and urban land use ranged from 1 to 68 percent. The streambed sediment samples were analyzed for a total of 141 contaminants, including 45 trace elements, 32 organochlorine compounds, and 64 semi-volatile organic compounds. The fish tissue samples were analyzed for 22 trace elements and 28 organochlorine compounds. Concentrations of selected contaminants in both streambed sediment and fish tissue correlated more strongly with population density than with other watershed characteristics. Cadmium, copper, lead, mercury, zinc, total polycyclic aromatic hydrocarbons (PAHs), total polychlorinated biphenyls (PCBs), dichloro diphenyl trichloroethane and metabolites (DDTM), and total chlordane in streambed sediment all showed strong positive correlations with population density (rho = 0.71 to 0.85, p value = 0.005 to <0.001). Correlations between population density and selected contaminants in fish tissue were less significant than with streambed sediment (rho = 0.62 to 0.72, p value = 0.03 to 0.008). Organic carbon concentrations were correlated with concentrations of arsenic, selenium, total PAHs, total PCBs, and DDTM in streambed sediment. The relation between concentrations of contaminants in streambed sediment and fish tissue was stronger for organochlorine compounds (rho = 0.75 to 0.55, p = 0.005 to 0.065) than for trace elements (rho = 0.63 to 0.53, p = 0.029 to 0.069). The NECB study area had the highest median concentrations of lead, mercury, total PAHs, total PCBs, and DDTM in streambed sediment and the highest median concentration of PCBs in fish tissue compared to 45 other NAWQA study units across the Nation. Concentrations of many of these constituents in streambed sediment also were frequently above the consensus-based Sediment-Quality Guidelines for the protection of wildlife, suggesting they are a threat to the health of aquatic biota in New England.

Theoretical and experimental study of polycyclic aromatic compounds as β-tubulin inhibitors.

PubMed

Olazarán, Fabian E; García-Pérez, Carlos A; Bandyopadhyay, Debasish; Balderas-Rentería, Isaias; Reyes-Figueroa, Angel D; Henschke, Lars; Rivera, Gildardo

2017-03-01

In this work, through a docking analysis of compounds from the ZINC chemical library on human β-tubulin using high performance computer cluster, we report new polycyclic aromatic compounds that bind with high energy on the colchicine binding site of β-tubulin, suggesting three new key amino acids. However, molecular dynamic analysis showed low stability in the interaction between ligand and receptor. Results were confirmed experimentally in in vitro and in vivo models that suggest that molecular dynamics simulation is the best option to find new potential β-tubulin inhibitors. Graphical abstract Bennett's acceptance ratio (BAR) method.

Design, synthesis and preliminary biological evaluation of indoline-2,3-dione derivatives as novel HDAC inhibitors.

PubMed

Jin, Kang; Li, Shanshan; Li, Xiaoguang; Zhang, Jian; Xu, Wenfang; Li, Xuechen

2015-08-01

Histone deacetylases (HDACs) are zinc-dependent or NAD(+) dependent enzymes and play a critical role in the process of tumor development. Herein a series of indoline-2,3-dione derivatives have been designed and synthesized as potential HDACs inhibitors. The preliminary biological evaluation showed that most compounds synthesized have exhibited moderate Hela cell nuclear extract inhibitory activities, among which compound 25a (IC50=10.13 nM) has shown the best efficacy. The anti-proliferative activities of some of these compounds were also discussed. Copyright © 2015. Published by Elsevier Ltd.

Characterization of the ZAT1p zinc transporter from Arabidopsis thaliana in microbial model organisms and reconstituted proteoliposomes.

PubMed

Bloss, Tanja; Clemens, Stephan; Nies, Dietrich H

2002-03-01

The ZAT1p zinc transporter from Arabidopsis thaliana (L.) Heynh. is a member of the cation diffusion facilitator (CDF) protein family. When heterologously expressed in Escherichia coli, ZAT1p bound zinc in a metal blot. Binding of zinc occurred mainly to the hydrophilic amino acid region from H182 to H232. A ZAT1p/ZAT1p*Delta(M1-I25) protein mixture was purified and reconstituted into proteoliposomes. Uptake of zinc into the proteoliposomes did not require a proton gradient across the liposomal membrane. ZAT1p did not transport cobalt, and transported cadmium at only 1% of the zinc transport rate. ZAT1p functioned as an uptake system for 65Zn2+ in two strains of the Gram-negative bacterium Ralstonia metallidurans, which were different in their content of zinc-efflux systems. The ZAT1 gene did not rescue increased zinc sensitivity of a Delta ZRC1single-mutant strain or of a Delta ZRC1 Delta COT1 double-mutant strain of Saccharomyces cerevisiae, but ZAT1 complemented this phenotype in a Delta SpZRC1 mutant strain of Schizosaccharomyces pombe.

Metal active site elasticity linked to activation of homocysteine in methionine synthases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koutmos, Markos; Pejchal, Robert; Bomer, Theresa M.

2008-04-02

Enzymes possessing catalytic zinc centers perform a variety of fundamental processes in nature, including methyl transfer to thiols. Cobalamin-independent (MetE) and cobalamin-dependent (MetH) methionine synthases are two such enzyme families. Although they perform the same net reaction, transfer of a methyl group from methyltetrahydrofolate to homocysteine (Hcy) to form methionine, they display markedly different catalytic strategies, modular organization, and active site zinc centers. Here we report crystal structures of zinc-replete MetE and MetH, both in the presence and absence of Hcy. Structural investigation of the catalytic zinc sites of these two methyltransferases reveals an unexpected inversion of zinc geometry uponmore » binding of Hcy and displacement of an endogenous ligand in both enzymes. In both cases a significant movement of the zinc relative to the protein scaffold accompanies inversion. These structures provide new information on the activation of thiols by zinc-containing enzymes and have led us to propose a paradigm for the mechanism of action of the catalytic zinc sites in these and related methyltransferases. Specifically, zinc is mobile in the active sites of MetE and MetH, and its dynamic nature helps facilitate the active site conformational changes necessary for thiol activation and methyl transfer.« less

Bioaccumulation and toxicity of zinc in the green alga, Cladophora glomerata.

PubMed

McHardy, B M; George, J J

1990-01-01

The bioaccumulation and toxicity of zinc in Cladophora glomerata from two populations in the River Roding, Essex, UK, were examined in experimental laboratory flowing-water channels. Plants were subjected to zinc concentrations ranging from 0 to 4.0 mg litre(-1) at current velocities of 20-33 cm s(-1) for up to 3 h. Zinc in algal tissue was then quantified and toxicity was assessed by the ability of the alga to grow in a recovery medium after the experimental treatment. There was little difference in zinc bioaccumulation between Cladophora from the site showing mild organic pollution and that from the site subjected to considerable inputs from urban and motorway runoff. Uptake of zinc increased with increasing concentration in the test solution and was linear and proportional up to 0.4 mg litre(-1). Three stages of uptake were identified with the most dramatic accumulation occurring in the first 10 min. Experimental concentration factors ranged from 1.9-5.2 x 10(3), which were in agreement with those previously obtained in the field. Cellular damage was evident in Cladophora subjected to 0.4 mg litre(-1) zinc, and this increased with increasing zinc concentration, thus leading to the conclusion that, at times, the levels of zinc found in the river could be potentially damaging.

Micronutrients and kelp cultures: Evidence for cobalt and manganese deficiency in Southern California deep seawater

USGS Publications Warehouse

Kuwabara, J.S.

1982-01-01

It has been suggested that naturally occurring copper and zinc concentrations in deep seawater are toxic to marine organisms when the free ion forms are overabundant. The effects of micronutrients on the growth of gametophytes of the ecologically and commercially significant giant kelp (Macrocystis pyrifera) were studied in defined media. The results indicate that toxic copper and zinc ion concentrations as well as cobalt and manganese deficiencies may be among the factors controlling the growth of marine organisms in nature. Copyright ?? 1982 AAAS.

Rational screening of peroxisome proliferator-activated receptor-γ agonists from natural products: potential therapeutics for heart failure.

PubMed

Chen, Rui; Wan, Jing; Song, Jing; Qian, Yan; Liu, Yong; Gu, Shuiming

2017-12-01

Peroxisome proliferator-activated receptor-γ (PPARγ) is a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors. Activation of PPARγ pathway has been shown to enhance fatty acid oxidation, improve endothelial cell function, and decrease myocardial fibrosis in heart failure. Thus, the protein has been raised as an attractive target for heart failure therapy. This work attempted to discover new and potent PPARγ agonists from natural products using a synthetic strategy of computer virtual screening and transactivation reporter assay. A large library of structurally diverse, drug-like natural products was compiled, from which those with unsatisfactory pharmacokinetic profile and/or structurally redundant compounds were excluded. The binding mode of remaining candidates to PPARγ ligand-binding domain (LBD) was computationally modelled using molecular docking and their relative binding potency was ranked by an empirical scoring scheme. Consequently, eight commercially available hits with top scores were selected and their biological activity was determined using a cell-based reporter-gene assay. Four natural product compounds, namely ZINC13408172, ZINC4292805, ZINC44179 and ZINC901461, were identified to have high or moderate agonistic potency against human PPARγ with EC 50 values of 0.084, 2.1, 0.35 and 5.6 μM, respectively, which are comparable to or even better than that of the approved PPARγ full agonists pioglitazone (EC 50  =   0.16 μM) and rosiglitazone (EC 50  =   0.034 μM). Hydrophobic interactions and van der Waals contacts are the primary chemical forces to stabilize the complex architecture of PPARγ LBD domain with these agonist ligands, while few hydrogen bonds, salt bridges and/or π-π stacking at the complex interfaces confer selectivity and specificity for the domain-agonist recognition. The integrated in vitro-in silico screening strategy can be successfully applied to rational discovery of biologically active compounds. The newly identified natural products with PPARγ agonistic potency are considered as promising lead scaffolds to develop novel chemical therapeutics for heart failure.

Anticorrosion Properties of Pigments based on Ferrite Coated Zinc Particles

NASA Astrophysics Data System (ADS)

Benda, P.; Kalendová, A.

The paper deals with a new anticorrosion pigment, synthesized on a core-shell basis. For its syntheses a starting substance is used that forms the lamellar shaped core; namely lamellar zinc. The cover of the core is represented by zinc oxide, which is in fact partly oxidized lamellar zinc core, and is created during the calcination of the pigment. The compound that forms the top layer of the core, a ferrite, is also formed during calcination. The formula for the prepared pigment is then defined as MexZn1-xFe2O4/Zn and the formula of thin ferrite layer is MexZn1-xFe2O4 (where Me = Ca, Mg). Due to its shape, this anticorrosion pigment includes another anticorrosion effect, the so called "barrier effect". The mechanisms of anticorrosion effect, corrosion efficiency and mechanical properties were investigated for epoxy-ester paint systems with 10%pigment volume concentration (PVC). Mechanical tests were performed to determine the adhesiveness and mechanical resistance of paints and accelerated corrosion tests were carried out to evaluate efficiency against chemical degradation factors.

Zinc incorporation improves biological activity of beta-tricalcium silicate resin-based cement.

PubMed

Osorio, Raquel; Yamauti, Monica; Sauro, Salvatore; Watson, Tim F; Toledano, Manuel

2014-11-01

Matrix metalloproteinase (MMP) inhibition may improve endodontic treatment prognosis. The purpose of this study was to determine if zinc incorporation into experimental resin cements containing bioactive fillers may modulate MMP-mediated collagen degradation of dentin. Human dentin samples untreated and demineralized using 10% phosphoric acid or 0.5 mol/L EDTA were infiltrated with the following experimental resins: (1) unfilled resin, (2) resin with Bioglass 45S5 particles (OSspray, London, UK), (3) resin with beta-tricalcium silicate particles (βTCS), (4) resin with zinc-doped Bioglass 45S5, and (5) resin with zinc-doped βTCS particles. The specimens were stored in artificial saliva (for 24 hours, 1 week, and 4 weeks) and submitted to radioimmunoassay to quantify C-terminal telopeptide. Scanning electron microscopy analysis was also undertaken on dentin samples after 4 weeks of storage. Collagen degradation was prominent both in phosphoric acid and EDTA-treated dentin. Resin infiltration strongly reduced MMP activity in demineralized dentin. Resin containing Bioglass 45S5 particles exerted higher and stable protection of collagen. The presence of zinc in βTCS particles increases MMP inhibition. Different mineral precipitation was attained in dentin infiltrated with the resin cements containing bioactive fillers. MMP degradation of dentin collagen is strongly reduced after resin infiltration of dentin. Zinc incorporation in βTCS particles exerted an additional protection against MMP-mediated collagen degradation. However, it did not occur in resin containing Bioglass 45S5 particles, probably because of the formation of phosphate-zinc compounds. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Selective Inducible Nitric Oxide Synthase Inhibitor Reversed Zinc Chloride-Induced Spatial Memory Impairment via Increasing Cholinergic Marker Expression.

PubMed

Tabrizian, Kaveh; Azami, Kian; Belaran, Maryam; Soodi, Maliheh; Abdi, Khosrou; Fanoudi, Sahar; Sanati, Mehdi; Mottaghi Dastjerdi, Negar; Soltany Rezaee-Rad, Mohammad; Sharifzadeh, Mohammad

2016-10-01

Zinc, an essential micronutrient and biochemical element of the human body, plays structural, catalytic, and regulatory roles in numerous physiological functions. In the current study, the effects of a pretraining oral administration of zinc chloride (10, 25, and 50 mg/kg) for 14 consecutive days and post-training bilateral intra-hippocampal infusion of 1400W as a selective inducible nitric oxide synthase (iNOS) inhibitor (10, 50, and 100 μM/side), alone and in combination, on the spatial memory retention in Morris water maze (MWM) were investigated. Animals were trained for 4 days and tested 48 h after completion of training. Also, the molecular effects of these compounds on the expression of choline acetyltransferase (ChAT), as a cholinergic marker in the CA1 region of the hippocampus and medial septal area (MSA), were evaluated. Behavioral and molecular findings of this study showed that a 2-week oral administration of zinc chloride (50 mg/kg) impaired spatial memory retention in MWM and decreased ChAT expression. Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400W revealed a significant increase in ChAT immunoreactivity. Furthermore, post-training bilateral intra-hippocampal infusion of 1400W into the CA1 region of the hippocampus reversed zinc chloride-induced spatial memory impairment in MWM and significantly increased ChAT expression in comparison with zinc chloride-treated animals. Taken together, these results emphasize the role of selective iNOS inhibitors in reversing zinc chloride-induced spatial memory deficits via modulation of cholinergic marker expression.

Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate.

PubMed

Cursino, Ana Cristina Trindade; Gardolinski, José Eduardo Ferreira da Costa; Wypych, Fernando

2010-07-01

Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products. Copyright 2010 Elsevier Inc. All rights reserved.

Preparation and characterization of an anti-inflammatory agent based on a zinc-layered hydroxide-salicylate nanohybrid and its effect on viability of Vero-3 cells

PubMed Central

Ramli, Munirah; Hussein, Mohd Zobir; Yusoff, Khatijah

2013-01-01

A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells. PMID:23345976

Disruption of redox catalytic functions of peroxiredoxin-thioredoxin complex in Mycobacterium tuberculosis H37Rv using small interface binding molecules.

PubMed

Gurung, Arun Bahadur; Das, Amit Kumar; Bhattacharjee, Atanu

2017-04-01

Mycobacterium tuberculosis has distinctive ability to detoxify various microbicidal superoxides and hydroperoxides via a redox catalytic cycle involving thiol reductants of peroxiredoxin (Prx) and thioredoxin (Trx) systems which has conferred on it resistance against oxidative killing and survivability within host. We have used computational approach to disrupt catalytic functions of Prx-Trx complex which can possibly render the pathogen vulnerable to oxidative killing in the host. Using protein-protein docking method, we have successfully constructed the Prx-Trx complex. Statistics of interface region revealed contact area of each monomer less than 1500Å 2 and enriched in polar amino acids indicating transient interaction between Prx and Trx. We have identified ZINC40139449 as a potent interface binding molecule through virtual screening of drug-like compounds from ZINC database. Molecular dynamics (MD) simulation studies showed differences in structural properties of Prx-Trx complex both in apo and ligand bound states with regard to root mean square deviation (RMSD), radius of gyration (Rg), root mean square fluctuations (RMSF), solvent accessible surface area (SASA) and number of hydrogen bonds (NHBs). Interestingly, we found stability of two conserved catalytic residues Cys61 and Cys174 of Prx and conserved catalytic motif, WCXXC of Trx upon binding of ZINC40139449. The time dependent displacement study reveals that the compound is quite stable in the interface binding region till 30ns of MD simulation. The structural properties were further validated by principal component analysis (PCA). We report ZINC40139449 as promising lead which can be further evaluated by in vitro or in vivo enzyme inhibition assays. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploitation of knowledge databases in the synthesis of zinc(II) malonates with photo-sensitive and photo-insensitive N,N'-containing linkers.

PubMed

Zorina-Tikhonova, Ekaterina N; Chistyakov, Aleksandr S; Kiskin, Mikhail A; Sidorov, Aleksei A; Dorovatovskii, Pavel V; Zubavichus, Yan V; Voronova, Eugenia D; Godovikov, Ivan A; Korlyukov, Alexander A; Eremenko, Igor L; Vologzhanina, Anna V

2018-05-01

Photoinitiated solid-state reactions are known to affect the physical properties of coordination polymers, such as fluorescence and sorption behaviour, and also afford extraordinary architectures ( e.g. three-periodic structures with polyorganic ligands). However, the construction of novel photo-sensitive coordination polymers requires an understanding of the factors which govern the mutual disposition of reactive fragments. A series of zinc(II) malonate complexes with 1,2-bis(pyridin-4-yl)ethylene and its photo-insensitive analogues has been synthesized for the purpose of systematic analysis of their underlying nets and mutual disposition of N -donor ligands. The application of a big data-set analysis for the prediction of a variety of possible complex compositions, coordination environments and networks for a four-component system has been demonstrated for the first time. Seven of the nine compounds possess one of the highly probable topologies for their underlying nets; in addition, two novel closely related four-coordinated networks were obtained. Complexes containing 1,2-bis(pyridin-4-yl)ethylene and 1,2-bis(pyridin-4-yl)ethane form isoreticular compounds more readily than those with 4,4'-bipyridine and 1,2-bis(pyridin-4-yl)ethylene. The effects of the precursor, either zinc(II) nitrate or zinc(II) acetate, on the composition and dimensionality of the resulting architecture are discussed. For three of the four novel complexes containing 1,2-bis(pyridin-4-yl)ethylene, the single-crystal-to-single-crystal [2 + 2] cycloaddition reactions were carried out. UV irradiation of these crystals afforded either the 0D→1D or the 3D→3D transformations, with and without network changes. One of the two 3D→3D transformations was accompanied by solvent (H 2 O) cleavage.

Application of CE-ICP-MS and CE-ESI-MS/MS for identification of Zn-binding ligands in Goji berries extracts.

PubMed

Ruzik, Lena; Kwiatkowski, Piotr

2018-06-01

The identification of groups of ligands binding metals is a crucial issue for the better understanding of their bioaccessibility. In the current study, we have intended an approach for identification of Zn-binding ligands based on using capillary electrophoresis combined with inductively coupled plasma mass spectrometry (CE-ICP-MS) and tandem electrospray ionization mass spectrometry (CE-ESI-MS/MS). The approach, which featured the use of the coupling of capillary electrophoresis with inductively coupled plasma mass spectrometry allows to separate and observe zinc ions present in complexes with respect to their size and charge and to identify nine compounds with zinc isotopic profile. CE-ICP-MS provides us with information about presence of zinc species and elemental information about zinc distribution. CE-ESI-MS/MS provide us with information about the most favorable Zn binding ligands: amino acids, flavonols, stilbenoids, fenolic acids and carotenoids. The presented work is the continuation of previous studies based on using LC-ESI-MS/MS, though, now we presented a new solutions with the possibility of changing detectors without changing the separation techniques, what is important without re-optimizing the method. The new presented method allows to identify the zinc-binding ligands in shorter time. Copyright © 2018 Elsevier B.V. All rights reserved.

A charge-stabilizing, multimodular, ferrocene-bis(triphenylamine)-zinc-porphyrin-fullerene polyad.

PubMed

Wijesinghe, Channa A; El-Khouly, Mohamed E; Zandler, Melvin E; Fukuzumi, Shunichi; D'Souza, Francis

2013-07-15

A novel multimodular donor-acceptor polyad featuring zinc porphyrin, fullerene, ferrocene, and triphenylamine entities was designed, synthesized, and studied as a charge-stabilizing, photosynthetic-antenna/reaction-center mimic. The ferrocene and fullerene entities, covalently linked to the porphyrin ring, were distantly separated to accomplish the charge-separation/hole-migration events leading to the creation of a long-lived charge-separated state. The geometry and electronic structures of the newly synthesized compound was deduced by B3LYP/3-21G(*) optimization, while the energy levels for different photochemical events was established using data from the optical absorption and emission, and electrochemical studies. Excitation of the triphenylamine entities revealed singlet-singlet energy transfer to the appended zinc porphyrin. As predicted from the energy levels, photoinduced electron transfer from both the singlet and triplet excited states of the zinc porphyrin to fullerene followed by subsequent hole migration involving ferrocene was witnessed from the transient absorption studies. The charge-separated state persisted for about 8.5 μs and was governed by the distance between the final charge-transfer product, that is, a species involving a ferrocenium cation and a fullerene radical anion, with additional influence from the charge-stabilizing triphenylamine entities located on the zinc-porphyrin macrocycle. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

Gupta, Raghubir P.; Gangwal, Santosh K.; Jain, Suresh C.

1993-01-01

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub.3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

Gupta, R.P.; Gangwal, S.K.; Jain, S.C.

1993-10-19

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 [mu]m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO[sub 3]; and then indurating it at 800 to 900 C for a time sufficient to produce attrition-resistant granules.

Effects of Lumbriculus variegatus (Annelida, Oligochaete) bioturbation on zinc sediment chemistry and toxicity to the epi-benthic invertebrate Chironomus tepperi (Diptera: Chironomidae).

PubMed

Colombo, Valentina; Pettigrove, Vincent J; Hoffmann, Ary A; Golding, Lisa A

2016-09-01

Classical laboratory-based single-species sediment bioassays do not account for modifications to toxicity from bioturbation by benthic organisms which may impact predictions of contaminated sediment risk to biota in the field. This study aims to determine the effects of bioturbation on the toxicity of zinc measured in a standard laboratory bioassay conducted with chironomid larvae (Chironomus tepperi). The epi-benthic chironomid larvae were exposed to two different levels of sediment contamination (1600 and 1980 mg/kg of dry weight zinc) in the presence or absence of annelid worms (Lumbriculus variegatus) which are known to be tolerant to metal and to have a large impact on sediment properties through bioturbation. Chironomids had 5-6x higher survival in the presence of L. variegatus which shows that bioturbation had a beneficial effect on the chironomid larvae. Chemical analyses showed that bioturbation induced a flux of zinc from the pore water into the water column, thereby reducing the bioavailability of zinc in pore water to the chironomid larvae. This also suggested that pore water was the major exposure path for the chironomids to metals in sediment. During the study, annelid worms (Oligochaetes) produced a thin layer of faecal pellets at the sediment surface, a process known to: (i) create additional adsorption sites for zinc, thus reducing its availability, (ii) increase the microbial abundance that in turn could represent an additional food source for opportunistic C. tepperi larvae, and (iii) modify the microbial community's structure and alter the biogeochemical processes it governs thus indirectly impact zinc toxicity. This study represents a contribution in recognising bioturbating organisms as "ecological engineers" as they directly and indirectly influence metal bioavailability and impact other sediment-inhabiting species. This is significant and should be considered in risk assessment of zinc levels (and other metals) in contaminated sediment when extrapolating from laboratory studies to the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

New cyclometalated Iridium(III) beta-dicetone complex as phosphorescent dopant in Organic light emitting devices

NASA Astrophysics Data System (ADS)

Ivanov, P.; Petrova, P.; Stanimirov, S.; Tomova, R.

2017-01-01

A new Bis[4-(benzothiazolato-N,C2‧-2-yl)-N,N-dimethylaniline]Iridium(III) acetylacetonate (Me2N-bt) 2Ir(acac) was synthesized and identified by 1H NMR and elemental analysis. The application of the new compound as a dopant in the hole transporting layer (HTL) of Organic light emitting diode (OLED) structure: HTL/EL/ETL, where HTL was N,N’-bis(3-methylphenyl)-N,N’-diphenylbenzidine (TPD), incorporated in Poly(N-vinylcarbazole) (PVK) matrix, EL - electroluminescent layer of Bis(8-hydroxy-2-methylquinoline)-(4-phenylpheno-xy)aluminum (BAlq) and ETL - electron-transporting layer of Tris-(8-hydroxyquinoline) aluminum (Alq3) or Bis[2-(2-benzothiazoly) phenolato]zinc (Zn(btz)2). We established that the electroluminescent spectra of OLEDs at different concentrations of the dopant were basically the sum of the greenish-blue emission of BAlq and yellowish-green emission of Ir complex. It was found that with increasing of the dopant concentration the relative electroluminescent intensity of Iridium complex emission increased and this of BAlq decreased and as a result the fine tuning of OLED color was observed.

Toxicity to Eisenia andrei and Folsomia candida of a metal mixture applied to soil directly or via an organic matrix.

PubMed

Natal-da-Luz, T; Ojeda, G; Pratas, J; Van Gestel, C A M; Sousa, J P

2011-09-01

Regulatory limits for chemicals and ecological risk assessment are usually based on the effects of single compounds, not taking into account mixture effects. The ecotoxicity of metal-contaminated sludge may, however, not only be due to its metal content. Both the sludge matrix and the presence of other toxicants may mitigate or promote metal toxicity. To test this assumption, the toxicity of soils recently amended with an industrial sludge predominantly contaminated with chromium, copper, nickel, and zinc and soils freshly spiked with the same mixture of metals was evaluated through earthworm (Eisenia andrei) and collembolan (Folsomia candida) reproduction tests. The sludge was less toxic than the spiked metal mixture for E. andrei but more toxic for F. candida. Results obtained for the earthworms suggest a decrease in metal bioavailability promoted by the high organic matter content of the sludge. The higher toxicity of the sludge for F. candida was probably due to the additive toxic effect of other pollutants. Copyright © 2011 Elsevier Inc. All rights reserved.

Genotoxic effects and serum abnormalities in residents of regions proximal to e-waste disposal facilities in Jinghai, China.

PubMed

Li, KeQiu; Liu, ShaSha; Yang, QiaoYun; Zhao, YuXia; Zuo, JunFang; Li, Ran; Jing, YaQing; He, XiaoBo; Qiu, XingHua; Li, Guang; Zhu, Tong

2014-07-01

Electronic waste (e-waste) disposal is a growing problem in China, and its effects on human health are a concern. To determine the concentrations of pollutants in peripheral blood and genetic aberrations near an e-waste disposal area in Jinghai, China, blood samples were collected from 30 (age: 41±11.01 years) and 28 (age: 33±2.14 years) individuals residing within 5 and 40km of e-waste disposal facilities in Jinghai (China), respectively, during the week of October 21-28, 2011. Levels of inorganic pollutants (calcium, copper, iron, lead, magnesium, selenium, and zinc) and malondialdehyde (MDA), identities of persistent organic pollutants (POPs), micronucleus rates, and lymphocyte subsets were analyzed in individuals. Total RNA expression profiles were analyzed by group and gender. The population group living in proximity to the e-waste site displayed significantly higher mean levels of copper, zinc, lead, MDAs, POPs (B4-6DE, B7-9DE, total polychlorinated biphenyls, and BB-153). In addition, micronucleus rates of close-proximity group were higher compared with the remote group (18.27% vs. 7.32%). RNA expression of genes involved in metal ion binding and transport, oxidation/reduction, immune defense, and tumorigenesis varied between groups, with men most detrimentally affected (p<0.05). CD4(+)/CD8(+)T cell ratios, CD4(+)CD25(nt/hi)CD127(lo)regulatory T cell percentages, and CD95 expression were greater in the e-waste group (p<0.05). Residing in close proximity to e-waste disposal facilities (≤5km) may be associated with the accumulation of potentially harmful inorganic/organic compounds and gender-preferential genetic aberrations. Copyright © 2014 Elsevier Inc. All rights reserved.

Computational investigation of the selectivity of salen and tetrahydrosalen compounds towards the tumor-associated hCA XII isozyme.

PubMed

Akdemir, Atilla; De Monte, Celeste; Carradori, Simone; Supuran, Claudiu T

2015-02-01

In previous work, 14 salen and tetrahydrosalen compounds have been synthesized and tested in enzyme inhibition assays against cytosolic human carbonic anhydrase isozymes I and II (hCA I and II) and tumor-associated isozymes IX and XII (hCA IX and XII). These compounds show selectivity against hCA XII over hCA I, II and IX. In this study, molecular modeling and docking studies were applied to understand this preference of the compounds for hCA XII. Most likely, the compounds can displace the zinc-bound water molecule of hCA XII to form a direct interaction with the Zn(2+) ion. In the other isozymes, the compounds might not be able to displace the water molecule nor are they expected to interact with the Zn(2+) ion.

Polymorphic improvement of Stillinger-Weber potential for InGaN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Xiaowang W.; Jones, Reese E.; Chu, Kevin

A Stillinger-Weber potential is computationally very efficient for molecular dynamics simulations. Despite its simple mathematical form, the Stillinger-Weber potential can be easily parameterized to ensure that crystal structures with tetrahedral bond angles (e.g., diamond-cubic, zinc-blende, and wurtzite) are stable and have the lowest energy. As a result, the Stillinger-Weber potential has been widely used to study a variety of semiconductor elements and alloys. When studying an A-B binary system, however, the Stillinger-Weber potential is associated with two major drawbacks. First, it significantly overestimates the elastic constants of elements A and B, limiting its use for systems involving both compounds andmore » elements (e.g., an A/AB multilayer). Second, it prescribes equal energy for zinc-blende and wurtzite crystals, limiting its use for compounds with large stacking fault energies. Here in this paper, we utilize the polymorphic potential style recently implemented in LAMMPS to develop a modified Stillinger-Weber potential for InGaN that overcomes these two problems.« less

Polymorphic improvement of Stillinger-Weber potential for InGaN

NASA Astrophysics Data System (ADS)

Zhou, X. W.; Jones, R. E.; Chu, K.

2017-12-01

A Stillinger-Weber potential is computationally very efficient for molecular dynamics simulations. Despite its simple mathematical form, the Stillinger-Weber potential can be easily parameterized to ensure that crystal structures with tetrahedral bond angles (e.g., diamond-cubic, zinc-blende, and wurtzite) are stable and have the lowest energy. As a result, the Stillinger-Weber potential has been widely used to study a variety of semiconductor elements and alloys. When studying an A-B binary system, however, the Stillinger-Weber potential is associated with two major drawbacks. First, it significantly overestimates the elastic constants of elements A and B, limiting its use for systems involving both compounds and elements (e.g., an A/AB multilayer). Second, it prescribes equal energy for zinc-blende and wurtzite crystals, limiting its use for compounds with large stacking fault energies. Here, we utilize the polymorphic potential style recently implemented in LAMMPS to develop a modified Stillinger-Weber potential for InGaN that overcomes these two problems.

HDAC inhibitors: a 2013-2017 patent survey.

PubMed

Faria Freitas, Micaela; Cuendet, Muriel; Bertrand, Philippe

2018-04-19

Zinc-dependent histone deacetylases (HDAC) inhibitors represent an important class of biologically active compounds with four of them approved by the FDA. A wide range of molecules has been reported for applications in several human diseases.Area covered: This review covers recent efforts in the synthesis and applications of HDAC inhibitors from 2013-2017.Expert opinion: HDAC inhibitors represent an important class of biologically active compounds for single or combination therapies. The current synthetic methodologies are oriented towards selective HDAC isoforms to achieve better therapeutic effects. Among the recent patents available, most of them focus on HDAC6 selective inhibitors. Beside this search for isoform selectivity, the quest for zinc binding groups with better pharmacokinetic properties and high potency against HDACs only motivates medicinal chemists, as well as the design of inhibitors targeting HDACs and at the same time another biological target. If the major applications are for anticancer activity, one can note the emerging applications in neurological or metabolic disorders or for the stimulation of the immune system.

Polymorphic improvement of Stillinger-Weber potential for InGaN

DOE PAGES

Zhou, Xiaowang W.; Jones, Reese E.; Chu, Kevin

2017-12-21

A Stillinger-Weber potential is computationally very efficient for molecular dynamics simulations. Despite its simple mathematical form, the Stillinger-Weber potential can be easily parameterized to ensure that crystal structures with tetrahedral bond angles (e.g., diamond-cubic, zinc-blende, and wurtzite) are stable and have the lowest energy. As a result, the Stillinger-Weber potential has been widely used to study a variety of semiconductor elements and alloys. When studying an A-B binary system, however, the Stillinger-Weber potential is associated with two major drawbacks. First, it significantly overestimates the elastic constants of elements A and B, limiting its use for systems involving both compounds andmore » elements (e.g., an A/AB multilayer). Second, it prescribes equal energy for zinc-blende and wurtzite crystals, limiting its use for compounds with large stacking fault energies. Here in this paper, we utilize the polymorphic potential style recently implemented in LAMMPS to develop a modified Stillinger-Weber potential for InGaN that overcomes these two problems.« less

Analysis of waterborne paints by gas chromatography-mass spectrometry with a temperature-programmable pyrolyzer.

PubMed

Nakamura, S; Takino, M; Daishima, S

2001-04-06

Gas chromatography-mass spectrometry (GC-MS) with a temperature-programmable pyrolyzer was used for the analysis of waterborne paints. Evolved gas analysis (EGA) profiles of the waterborne paints were obtained by this temperature-programmed pyrolysis directly coupled with MS via a deactivated metal capillary tube. The EGA profile suggested the optimal thermal desorption conditions for solvents and additives and the subsequent optimal pyrolysis temperature for the remaining polymeric material. Polymers were identified from pyrograms with the assistance of a new polymer library. The solvents were identified from the electron ionization mass spectra with the corresponding chemical ionization mass spectra. The additive was identified as zinc pyrithione by comparison with authentic standard. Zinc pyrithione cannot be analyzed by GC-MS as it is. However, the thermal decomposition products of zinc pyrithione could be detected. The information on the decomposition temperature and products was useful for the identification of the original compound.

Electronic properties of III-nitride semiconductors: A first-principles investigation using the Tran-Blaha modified Becke-Johnson potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Araujo, Rafael B., E-mail: rafaelbna@gmail.com; Almeida, J. S. de, E-mail: jailton-almeida@hotmail.com; Ferreira da Silva, A.

In this work, we use density functional theory to investigate the influence of semilocal exchange and correlation effects on the electronic properties of III-nitride semiconductors considering zinc-blende and wurtzite crystal structures. We find that the inclusion of such effects through the use of the Tran-Blaha modified Becke-Johnson potential yields an excellent description of the electronic structures of these materials giving energy band gaps which are systematically larger than the ones obtained with standard functionals such as the generalized gradient approximation. The discrepancy between the experimental and theoretical band gaps is then significantly reduced with semilocal exchange and correlation effects. However,more » the effective masses are overestimated in the zinc-blende nitrides, but no systematic trend is found in the wurtzite compounds. New results for energy band gaps and effective masses of zinc-blende and wurtzite indium nitrides are presented.« less

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions

PubMed Central

Omae, Iwao

2016-01-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO2 and H2, and hydrogen production from the formic acid. This formic acid can be a useful agent for H2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g., dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO2. 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N,N-dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds. PMID:28503084

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions.

PubMed

Omae, Iwao

2016-04-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO 2 and H 2 , and hydrogen production from the formic acid. This formic acid can be a useful agent for H 2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g. , dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO 2 . 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N , N -dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds.

Design, synthesis and anticancer activity of piperazine hydroxamates and their histone deacetylase (HDAC) inhibitory activity.

PubMed

Chetan, Bhadaliya; Bunha, Mahesh; Jagrat, Monika; Sinha, Barij Nayan; Saiko, Philipp; Graser, Geraldine; Szekeres, Thomas; Raman, Ganapathy; Rajendran, Praveen; Moorthy, Dhatchana; Basu, Arijit; Jayaprakash, Venkatesan

2010-07-01

Six compounds were synthesized with piperazine in linker region and hydroxamate as Zinc Binding Group (ZBG). They were screened against three cancer cell-lines (NCIH460; HCT116; U251). Compounds 5c and 5f with GI(50) value of 9.33+/-1.3 microM and 12.03+/-4 microM, respectively, were tested for their inhibitory potential on hHDAC8. Compound 5c had IC(50) of 33.67 microM. Compounds were also screened for their anticancer activity against HL60 human promyelocytic leukemia cell line due to the presence of pharmacophoric features of RR inhibitors in them. Compound 5c had IC(50) of 0.6 microM at 48h. 2010 Elsevier Ltd. All rights reserved.

Antioxidant activity, polyphenolic contents and essential oil composition of Pimpinella anisum L. as affected by zinc fertilizer.

PubMed

Tavallali, Vahid; Rahmati, Sadegh; Bahmanzadegan, Atefeh

2017-11-01

The antioxidant activity and essential oil content of plants may vary considerably with respect to environmental conditions, especially nutrient availability. Among micronutrients, zinc (Zn) is needed by plants in only small amounts but is crucial to plant development. This study aimed to evaluate the effects of Zn fertilization on the antioxidant activity, polyphenolic contents and essential oil composition of Pimpinella anisum fruit. Foliar application of Zn fertilizer considerably increased the number of detected essential oil components from 27 to 45. Zinc application at a rate of 0.2% (w/v) significantly enhanced the levels of β-bisabolene, germacrene D, n-decane and α-zingiberene, whereas the opposite trend was observed for (E)-anethole and geijerene. Application of 0.2% Zn considerably increased the levels of phenolic compounds, with chlorogenic acid showing the highest content among eight phenolic compounds detected in treated plants. The maximum antioxidant activity was achieved through application of 0.2% Zn fertilizer. These findings indicated that the quality and quantity of anise fruit essential oil components were significantly altered by application of low levels of Zn. After foliar application of Zn, polyphenolic contents as well as antioxidant activity of anise fruit increased. Using Zn fertilizer is an efficient method to improve the pharmaceutical and food properties of anise fruit. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Combined effect of zinc ions and cationic antibacterial agents on intraoral volatile sulphur compounds (VSC).

PubMed

Young, A; Jonski, G; Rölla, G

2003-08-01

Volatile sulphur compounds (VSC) are major components of oral malodour. As both zinc ions and cationic antibacterial agents inhibit the formation of oral VSC, this study aimed to determine whether these agents combined have synergistic anti-VSC actions. Baseline oral VSC measurements of mouth air from 10 volunteers following cysteine rinsing (6mM, pH 7.2) were obtained using gas chromatography (GC). Subjects rinsed for 1 min with 10ml of the test solutions, 0.3% zinc acetate (Zn), 0.025% chlorhexidine (CHX), 0.025% cetyl pyridinium (CPC), and the combinations Zn+CHX and Zn+CPC. Cysteine rinses were repeated at 1h, 2h and 3h and VSC measurements recorded. Three subjects rinsed with the Zn+CHX combination and fasted for 9h, undergoing cysteine rinses and VSC measurements at 3h intervals. 10 microl of the test solutions were also added to 1ml aliquots of human whole saliva (n=8). Following incubation at 37 degrees C for 24h VSC levels in the saliva headspace were measured by GC. Inhibition of VSC formation and the fractional inhibitory index indicating synergy were calculated. Zn+CHX mouthrinse had a synergistic anti-VSC effect, and was effective for at least 9h. Zn+CPC mouthrinse was less effective. Both combinations showed a synergistic inhibiting effect in-vitro. Synergy between Zn and the antibacterial agents confirms different mechanisms of operation.

Zinc-65 in marine organisms along the Oregon and Washington coasts.

PubMed

WATSON, D G; DAVIS, J J; HANSON, W C

1961-06-09

The concentration of zinc-65 in marine animals and plants near the mouth of the Columbia River is presented. Amounts of radiozinc found in the biota diminished rapidly with the distance from the river mouth. The highest levels were found in plankton, algae, and mollusks. Of the human foods, oysters exhibited the highest levels.

The Zur regulon of Corynebacterium glutamicum ATCC 13032

PubMed Central

2010-01-01

Background Zinc is considered as an essential element for all living organisms, but it can be toxic at large concentrations. Bacteria therefore tightly regulate zinc metabolism. The Cg2502 protein of Corynebacterium glutamicum was a candidate to control zinc metabolism in this species, since it was classified as metalloregulator of the zinc uptake regulator (Zur) subgroup of the ferric uptake regulator (Fur) family of DNA-binding transcription regulators. Results The cg2502 (zur) gene was deleted in the chromosome of C. glutamicum ATCC 13032 by an allelic exchange procedure to generate the zur-deficient mutant C. glutamicum JS2502. Whole-genome DNA microarray hybridizations and real-time RT-PCR assays comparing the gene expression in C. glutamicum JS2502 with that of the wild-type strain detected 18 genes with enhanced expression in the zur mutant. The expression data were combined with results from cross-genome comparisons of shared regulatory sites, revealing the presence of candidate Zur-binding sites in the mapped promoter regions of five transcription units encoding components of potential zinc ABC-type transporters (cg0041-cg0042/cg0043; cg2911-cg2912-cg2913), a putative secreted protein (cg0040), a putative oxidoreductase (cg0795), and a putative P-loop GTPase of the COG0523 protein family (cg0794). Enhanced transcript levels of the respective genes in C. glutamicum JS2502 were verified by real-time RT-PCR, and complementation of the mutant with a wild-type zur gene reversed the effect of differential gene expression. The zinc-dependent expression of the putative cg0042 and cg2911 operons was detected in vivo with a gfp reporter system. Moreover, the zinc-dependent binding of purified Zur protein to double-stranded 40-mer oligonucleotides containing candidate Zur-binding sites was demonstrated in vitro by DNA band shift assays. Conclusion Whole-genome expression profiling and DNA band shift assays demonstrated that Zur directly represses in a zinc-dependent manner the expression of nine genes organized in five transcription units. Accordingly, the Zur (Cg2502) protein is the key transcription regulator for genes involved in zinc homeostasis in C. glutamicum. PMID:20055984

Evaluation of Substituted 1,2,3-Dithiazoles as Inhibitors of the Feline Immunodeficiency Virus (FIV) Nucleocapsid Protein via a Proposed Zinc Ejection Mechanism.

PubMed

Asquith, Christopher R M; Konstantinova, Lidia S; Laitinen, Tuomo; Meli, Marina L; Poso, Antti; Rakitin, Oleg A; Hofmann-Lehmann, Regina; Hilton, Stephen T

2016-10-06

A diverse library of 5-thieno-, 5-oxo-, and 5-imino-1,2,3-dithiazole derivatives was synthesized and evaluated for efficacy against the feline immunodeficiency virus (FIV) as a model for HIV in cells. Several diverse compounds from this series displayed nanomolar activity and low toxicity, representing a potential new class of compounds for the treatment of FIV and HIV. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fate of zinc in an electroplating sludge during electrokinetic treatments.

PubMed

Liu, Shou-Heng; Wang, H Paul

2008-08-01

Chemical structure of zinc in the electrokinetic treatments of an electroplating sludge has been studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies in the present work. The least-square fitted XANES spectra indicate that the main zinc compounds in the sludge were ZnCO(3) (75%), ZnOSiO(2) (17%) and Zn(OH)(2) (7%). Zinc in the sludge possessed a Zn-O bond distance of 2.07 A with a coordination number (CN) of 5. In the second shells, the bond distance of Zn-(O)-Si was 3.05 A (CN=2). An increase of Zn-(O)-Si (0.05 A) with a decrease of its CN (from 5 to <1) was found in the early stage of the electrokinetic treatment. Prolong the electrokinetic treatment time to 180 min, about 34% of Zn(II) was dissolved into the aqueous phase and about 68% of Zn(II) in the sludge (or 23% of total zinc) was migrated to the cathode under the electric field (5 V cm(-1)). The dissolution and electromigration rates of Zn(II) in the sludge were 1.0 and 0.6 mmol h(-1)g(-1) sludge, respectively during the electrokinetic treatment. This work also exemplifies the utilization of in situ EXAFS and XANES for revealing speciation and possible reaction pathways during the course of zinc recycling from the sludge by electrokinetic treatments.

Selective leaching process for the recovery of copper and zinc oxide from copper-containing dust.

PubMed

Wu, Jun-Yi; Chang, Fang-Chih; Wang, H Paul; Tsai, Ming-Jer; Ko, Chun-Han; Chen, Chih-Cheng

2015-01-01

The purpose of this study was to develop a resource recovery procedure for recovering copper and zinc from dust produced by copper smelting furnaces during the manufacturing of copper-alloy wires. The concentrations of copper in copper-containing dust do not meet the regulation standards defined by the Taiwan Environmental Protection Administration; therefore, such waste is classified as hazardous. In this study, the percentages of zinc and copper in the dust samples were approximately 38.4% and 2.6%, respectively. To reduce environmental damage and recover metal resources for industrial reuse, acid leaching was used to recover metals from these inorganic wastes. In the first stage, 2 N of sulphuric acid was used to leach the dust, with pH values controlled at 2.0-3.0, and a solid-to-liquid ratio of 1:10. The results indicated that zinc extraction efficiency was higher than 95%. A selective acid leaching process was then used to recover the copper content of the residue after filtration. In the second stage, an additional 1 N of sulphuric acid was added to the suspension in the selective leaching process, and the pH value was controlled at 1.5-2.0. The reagent sodium hydroxide (2 N) was used as leachate at a pH greater than 7. A zinc hydroxide compound formed during the process and was recovered after drying. The yields for zinc and copper were 86.9-93.5% and 97.0-98.9%, respectively.

Photodynamic evaluation of tetracarboxy-phthalocyanines in model systems.

PubMed

Alonso, Lais; Sampaio, Renato N; Souza, Thalita F M; Silva, Rodrigo C; Neto, Newton M Barbosa; Ribeiro, Anderson O; Alonso, Antonio; Gonçalves, Pablo J

2016-08-01

The present work reports the synthesis, photophysical and photochemical characterization and photodynamic evaluation of zinc, aluminum and metal free-base tetracarboxy-phthalocyanines (ZnPc, AlPc and FbPc, respectively). To evaluate the possible application of phthalocyanines as a potential photosensitizer the photophysical and photochemical characterization were performed using aqueous (phosphate-buffered solution, PBS) and organic (dimethyl sulfoxide, DMSO) solvents. The relative lipophilicity of the compounds was estimated by the octanol-water partition coefficient and the photodynamic activity evaluated through the photooxidation of a protein and photohemolysis. The photooxidation rate constants (k) were obtained and the hemolytic potential was evaluated by the maximum percentage of hemolysis achieved (Hmax) and the time (t50) to reach 50% of the Hmax. Although these phthalocyanines are all hydrophilic and possess very low affinity for membranes (log PO/W=-2.0), they led to significant photooxidation of bovine serum albumin (BSA) and photohemolysis. Our results show that ZnPc was the most efficient photosensitizer, followed by AlPc and FbPc; this order is the same as the order of the triplet and singlet oxygen quantum yields (ZnPc>AlPc>FbPc). Furthermore, together, the triplet, fluorescence and singlet oxygen quantum yields of zinc tetracarboxy-phthalocyanines suggest their potential for use in theranostic applications, which simultaneously combines photodiagnosis and phototherapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and characterization of [4-(2,4-dichlorophenoxybutyrate)-zinc layered hydroxide] nanohybrid

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir; Hashim, Norhayati; Yahaya, Asmah Hj.; Zainal, Zulkarnain

2010-05-01

A new layered organic-inorganic nanohybrid material in which an agrochemical, 4-(2,4-dichlorophenoxy)butyrate (DPBA) is intercalated into inorganic interlayers of zinc layered hydroxide (ZLH) was synthesized by direct reaction of aqueous DPBA solution with zinc oxide. The resulting nanohybrid is composed of the organic moieties, DPBA sandwiched between ZLH inorganic interlayers. The nanohybrid afforded well ordered crystalline layered structure, a basal spacing of 29.6 Å, 23.5% carbon (w/w) and 47.9% (w/w) loading of DPBA. FTIR study shows that the absorption bands of the resulting nanohybrid composed the FTIR characteristics of both the DPBA and ZLH which further confirmed the intercalation episode. The intercalated organic moiety in the form of nanohybrid is thermally more stable than its sodium salt. Scanning electron micrograph shows the ZnO precursor has very fine granular structure and transformed into a flake-like when the nanohybrid is formed. This work shows that the nanohybrid of DPBA-ZLH can be synthesized using simple, direct reaction of ZnO and DPBA under aqueous environment for the formation of a new generation of agrochemical.

Ultrasound-assisted preparation of a nanostructured zinc(II) amine pillar metal-organic framework as a potential sorbent for 2,4-dichlorophenol adsorption from aqueous solution.

PubMed

Abazari, Reza; Salehi, Ghazal; Mahjoub, Ali Reza

2018-09-01

Using a green and simple route with ultrasound illumination under atmospheric pressure and at room temperature, the nanosized preparation of a Zn(II) metal-organic framework, [Zn(ATA)(BPD)] ∞ (ATA = 2-aminoterephthalic acid), BPD = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), having nano-plate shape and 3D channel framework, was considered and the product was named as compound 1. The X-ray diffraction (XRD), scanning electron microscopy (SEM), IR spectroscopy, Brunauer-Emmett-Teller (BET), and thermogravimetric analysis (TGA) were used for characterization of the synthesized micro/nano-structures. Further, impact of different sonication times and initial reagent contents on the shape and size of the micro/nano-structures was investigated. The results show that under ultrasound irradiation non-aggregated plates with uniform morphology can be obtained with content of [0.0125] M of the initial reagents in the presence of triethylamine (TEA) at 120 min. Moreover, through N 2 adsorption, effect of the preparation route on the porosity was explored. The bulk and nano-plates of compound 1 were also studied for adsorption of 2,4-dichlorophenol as a pollutant sample. Kinetic studies indicated that 2,4-dichlorophenol adsorption via MOF nano-plates are of first-order kinetics. Also, MOF nano-plates have significantly been reutilized for five times while their adsorption properties have remained unchanged. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental confirmation of the predicted shallow donor hydrogen state in zinc oxide.

PubMed

Cox, S F; Davis, E A; Cottrell, S P; King, P J; Lord, J S; Gil, J M; Alberto, H V; Vilão, R C; Piroto Duarte, J; Ayres de Campos, N; Weidinger, A; Lichti, R L; Irvine, S J

2001-03-19

We confirm the recent prediction that interstitial protium may act as a shallow donor in zinc oxide, by direct spectroscopic observation of its muonium counterpart. On implantation into ZnO, positive muons--chemically analogous to protons in this context--form paramagnetic centers below about 40 K. The muon-electron contact hyperfine interaction, as well as the temperature and activation energy for ionization, imply a shallow level. Similar results for the cadmium chalcogenides suggest that such shallow donor states are generic to the II-VI compounds. The donor level depths should serve as a guide for the electrical activity of interstitial hydrogen.

Mechanically controlling the reversible phase transformation from zinc blende to wurtzite in AlN

DOE PAGES

Li, Zhen; Yadav, Satyesh; Chen, Youxing; ...

2017-04-10

III–V and other binary octet semiconductors often take two phase forms—wurtzite (wz) and zinc blende (zb) crystal structures—with distinct functional performance at room temperature. Here, we investigate how to control the synthesized phase structure to either wz or zb phase by tuning the interfacial strain by taking AlN as a representative III–V compound. Furthermore, by applying in situ mechanical tests at atomic scale in a transmission electron microscope, we observed the reversible phase transformation from zb to wz, and characterized the transition path—the collective glide of Shockley partials on every two {111} planes of the zb AlN.

Influence of zinc on the calcium carbonate biomineralization of Halomonas halophila

PubMed Central

2012-01-01

Background The salt tolerance of halophilic bacteria make them promising candidates for technical applications, like isolation of salt tolerant enzymes or remediation of contaminated saline soils and waters. Furthermore, some halophilic bacteria synthesize inorganic solids resulting in organic–inorganic hybrids. This process is known as biomineralization, which is induced and/or controlled by the organism. The adaption of the soft and eco-friendly reaction conditions of this formation process to technical syntheses of inorganic nano materials is desirable. In addition, environmental contaminations can be entrapped in biomineralization products which facilitate the subsequent removal from waste waters. The moderately halophilic bacteria Halomonas halophila mineralize calcium carbonate in the calcite polymorph. The biomineralization process was investigated in the presence of zinc ions as a toxic model contaminant. In particular, the time course of the mineralization process and the influence of zinc on the mineralized inorganic materials have been focused in this study. Results H. halophila can adapt to zinc contaminated medium, maintaining the ability for biomineralization of calcium carbonate. Adapted cultures show only a low influence of zinc on the growth rate. In the time course of cultivation, zinc ions accumulated on the bacterial surface while the medium depleted in the zinc contamination. Intracellular zinc concentrations were below the detection limit, suggesting that zinc was mainly bound extracellular. Zinc ions influence the biomineralization process. In the presence of zinc, the polymorphs monohydrocalcite and vaterite were mineralized, instead of calcite which is synthesized in zinc-free medium. Conclusions We have demonstrated that the bacterial mineralization process can be influenced by zinc ions resulting in the modification of the synthesized calcium carbonate polymorph. In addition, the shape of the mineralized inorganic material is chancing through the presence of zinc ions. Furthermore, the moderately halophilic bacterium H. halophila can be applied for the decontamination of zinc from aqueous solutions. PMID:23198844

The ZntA-like NpunR4017 plays a key role in maintaining homeostatic levels of zinc in Nostoc punctiforme.

PubMed

Hudek, L; Bräu, L; Michalczyk, A A; Neilan, B A; Meeks, J C; Ackland, M L

2015-12-01

Analysis of cellular response to zinc exposure provides insights into how organisms maintain homeostatic levels of zinc that are essential, while avoiding potentially toxic cytosolic levels. Using the cyanobacterium Nostoc punctiforme as a model, qRT-PCR analyses established a profile of the changes in relative mRNA levels of the ZntA-like zinc efflux transporter NpunR4017 in response to extracellular zinc. In cells treated with 18 μM of zinc for 1 h, NpunR4017 mRNA levels increased by up to 1300 % above basal levels. The accumulation and retention of radiolabelled (65)Zn by NpunR4107-deficient and overexpressing strains were compared to wild-type levels. Disruption of NpunR4017 resulted in a significant increase in zinc accumulation up to 24 % greater than the wild type, while cells overexpressing NpunR4107 accumulated 22 % less than the wild type. Accumulation of (65)Zn in ZntA(-) Escherichia coli overexpressing NpunR4017 was reduced by up to 21 %, indicating the capacity for NpunR4017 to compensate for the loss of ZntA. These findings establish the newly identified NpunR4017 as a zinc efflux transporter and a key transporter for maintaining zinc homeostasis in N. punctiforme.

Compromised zinc status of experimental rats as a consequence of prolonged iron & calcium supplementation.

PubMed

Jayalakshmi, S; Platel, Kalpana

2016-02-01

Iron supplementation is usually given to pregnant and lactating women who may also have marginal deficiency of zinc. The negative impact of supplemental iron and calcium on zinc status is a cause of concern. The present investigation was undertaken to examine the effect of inclusion of iron and calcium in the diet at supplementary levels on zinc status of experimental rats. Groups of experimental rats were maintained on diets supplemented with iron (Molar ratio - Zn:Fe 1:30) and calcium (Molar ratio - Zn:Ca 1:667) both individually and in combination for six weeks. Zinc status of these rats was assessed by determining zinc concentration in circulation and in organs, and the activities of zinc containing enzymes in serum and liver. The zinc status of experimental rats receiving supplemental levels of iron and calcium was significantly compromised. Zinc concentration in serum, kidney, spleen and liver was reduced significantly by both these minerals. Six weeks of supplementation of iron and calcium individually, significantly reduced the activity of liver and serum superoxide dismutase and alkaline phosphatase. Activity of liver alcohol dehydrogenase was lowered in calcium supplemented group and in calcium + iron supplemented group, while that of carbonic anhydrase was significantly reduced by iron, calcium and their combination. Supplemental levels of iron and calcium, both individually and in combination, significantly compromised the zinc status of experimental rats. This negative effect of these two minerals was more prominent when these were supplemented for a period of six weeks.

Hydrothermal synthesis and structural characterization of a novel three-dimensional supramolecular framework constructed by zinc salt and pyridine-2,5-dicarboxylate

NASA Astrophysics Data System (ADS)

Wang, Xinlong; Qin, Chao; Wang, Enbo; Hu, Changwen; Xu, Lin

2004-07-01

A novel metal-organic coordination polymer, [Zn(PDB)(H 2O) 2] 4 n (H 2PDB=pyridine-2,5-dicarboxylic acid), has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. Colorless crystals crystallized in the triclinic system, space group P-1, a=7.0562(14) Å, b=7.38526(15) Å, c=18.4611(4) Å, α=90.01(3)°, β=96.98(3)°, γ=115.67(3)°, V=859.1(3) Å 3, Z=1 and R=0.0334. The structure of the compound exhibits a novel three-dimensional supramolecular network, mainly based on multipoint hydrogen bonds originated from within and outside of a large 24-membered ring. Interestingly, the three-dimensional network consists of one-dimensional parallelogrammic channels in which coordinated water molecules point into the channel wall.

The ZIP family zinc transporters support the virulence of Cryptococcus neoformans

PubMed Central

Do, Eunsoo; Hu, Guanggan; Caza, Mélissa; Kronstad, James W.; Jung, Won Hee

2016-01-01

Zinc is an essential element in living organisms and a cofactor for various metalloproteins. To disseminate and survive, a pathogenic microbe must obtain zinc from the host, which is an environment with extremely limited zinc availability. In this study, we investigated the roles of the ZIP family zinc transporters Zip1 and Zip2 in the human pathogenic fungus Cryptococcus neoformans. Zip1 and Zip2 are homologous to Zrt1 and Zrt2 of the model fungus, Saccharomyces cerevisiae, respectively. We found that the expression of ZIP1 was regulated by the zinc concentration in the environment. Furthermore, the mutant lacking ZIP1 displayed a severe growth defect under zinc-limited conditions, while the mutant lacking ZIP2 displayed normal growth. Inductively coupled plasma–atomic emission spectroscopy analysis showed that the absence of Zip1 expression significantly reduced total cellular zinc levels relative to that in the wild type, while overexpression of Zip1 was associated with increased cellular zinc levels. These findings suggested that Zip1 plays roles in zinc uptake in C. neoformans. We also constructed a Zip1-FLAG fusion protein and found, by immunofluorescence, not only that the protein was localized to the periphery implying it is a membrane transporter, but also that the protein was N-glycosylated. Furthermore, the mutant lacking ZIP1 showed attenuated virulence in a murine inhalation model of cryptococcosis and reduced survival within murine macrophages. Overall, our data suggest that Zip1 plays essential roles in zinc transport and the virulence of C. neoformans. PMID:27118799

Characterization of the response to zinc deficiency in the cyanobacterium Anabaena sp. strain PCC 7120.

PubMed

Napolitano, Mauro; Rubio, Miguel Ángel; Santamaría-Gómez, Javier; Olmedo-Verd, Elvira; Robinson, Nigel J; Luque, Ignacio

2012-05-01

Zur regulators control zinc homeostasis by repressing target genes under zinc-sufficient conditions in a wide variety of bacteria. This paper describes how part of a survey of duplicated genes led to the identification of the open reading frame all2473 as the gene encoding the Zur regulator of the cyanobacterium Anabaena sp. strain PCC 7120. All2473 binds to DNA in a zinc-dependent manner, and its DNA-binding sequence was characterized, which allowed us to determine the relative contribution of particular nucleotides to Zur binding. A zur mutant was found to be impaired in the regulation of zinc homeostasis, showing sensitivity to elevated concentrations of zinc but not other metals. In an effort to characterize the Zur regulon in Anabaena, 23 genes containing upstream putative Zur-binding sequences were identified and found to be regulated by Zur. These genes are organized in six single transcriptional units and six operons, some of them containing multiple Zur-regulated promoters. The identities of genes of the Zur regulon indicate that Anabaena adapts to conditions of zinc deficiency by replacing zinc metalloproteins with paralogues that fulfill the same function but presumably with a lower zinc demand, and with inducing putative metallochaperones and membrane transport systems likely being involved in the scavenging of extracellular zinc, including plasma membrane ABC transport systems and outer membrane TonB-dependent receptors. Among the Zur-regulated genes, the ones showing the highest induction level encode proteins of the outer membrane, suggesting a primary role for components of this cell compartment in the capture of zinc cations from the extracellular medium.

Zinc oxide nanoparticles decrease the expression and activity of plasma membrane calcium ATPase, disrupt the intracellular calcium homeostasis in rat retinal ganglion cells.

PubMed

Guo, Dadong; Bi, Hongsheng; Wang, Daoguang; Wu, Qiuxin

2013-08-01

Zinc oxide nanoparticle is one of the most important materials with diverse applications. However, it has been reported that zinc oxide nanoparticles are toxic to organisms, and that oxidative stress is often hypothesized to be an important factor in cytotoxicity mediated by zinc oxide nanoparticles. Nevertheless, the mechanism of toxicity of zinc oxide nanoparticles has not been completely understood. In this study, we investigated the cytotoxic effect of zinc oxide nanoparticles and the possible molecular mechanism involved in calcium homeostasis mediated by plasma membrane calcium ATPase in rat retinal ganglion cells. Real-time cell electronic sensing assay showed that zinc oxide nanoparticles could exert cytotoxic effect on rat retinal ganglion cells in a concentration-dependent manner; flow cytometric analysis indicated that zinc oxide nanoparticles could lead to cell damage by inducing the overproduction of reactive oxygen species. Furthermore, zinc oxide nanoparticles could also apparently decrease the expression level and their activity of plasma membrane calcium ATPase, which finally disrupt the intracellular calcium homeostasis and result in cell death. Taken together, zinc oxide nanoparticles could apparently decrease the plasma membrane calcium ATPase expression, inhibit their activity, cause the elevated intracellular calcium ion level and disrupt the intracellular calcium homeostasis. Further, the disrupted calcium homeostasis will trigger mitochondrial dysfunction, generate excessive reactive oxygen species, and finally initiate cell death. Thus, the disrupted calcium homeostasis is involved in the zinc oxide nanoparticle-induced rat retinal ganglion cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

iTRAQ Analysis Reveals Mechanisms of Growth Defects Due to Excess Zinc in Arabidopsis1[W][OA

PubMed Central

Fukao, Yoichiro; Ferjani, Ali; Tomioka, Rie; Nagasaki, Nahoko; Kurata, Rie; Nishimori, Yuka; Fujiwara, Masayuki; Maeshima, Masayoshi

2011-01-01

The micronutrient zinc is essential for all living organisms, but it is toxic at high concentrations. Here, to understand the effects of excess zinc on plant cells, we performed an iTRAQ (for isobaric tags for relative and absolute quantification)-based quantitative proteomics approach to analyze microsomal proteins from Arabidopsis (Arabidopsis thaliana) roots. Our approach was sensitive enough to identify 521 proteins, including several membrane proteins. Among them, IRT1, an iron and zinc transporter, and FRO2, a ferric-chelate reductase, increased greatly in response to excess zinc. The expression of these two genes has been previously reported to increase under iron-deficient conditions. Indeed, the concentration of iron was significantly decreased in roots and shoots under excess zinc. Also, seven subunits of the vacuolar H+-ATPase (V-ATPase), a proton pump on the tonoplast and endosome, were identified, and three of them decreased significantly in response to excess zinc. In addition, excess zinc in the wild type decreased V-ATPase activity and length of roots and cells to levels comparable to those of the untreated de-etiolated3-1 mutant, which bears a mutation in V-ATPase subunit C. Interestingly, excess zinc led to the formation of branched and abnormally shaped root hairs, a phenotype that correlates with decreased levels of proteins of several root hair-defective mutants. Our results point out mechanisms of growth defects caused by excess zinc in which cross talk between iron and zinc homeostasis and V-ATPase activity might play a central role. PMID:21325567

Quinolone-based HDAC inhibitors.

PubMed

Balasubramanian, Gopalan; Kilambi, Narasimhan; Rathinasamy, Suresh; Rajendran, Praveen; Narayanan, Shridhar; Rajagopal, Sridharan

2014-08-01

HDAC inhibitors emerged as promising drug candidates in combating wide variety of cancers. At present, two of the compounds SAHA and Romidepsin were approved by FDA for cutaneous T-cell lymphoma and many are in various clinical phases. A new quinolone cap structure was explored with hydroxamic acid as zinc-binding group (ZBG). The pan HDAC inhibitory and antiproliferative activities against three human cancer cell lines HCT-116 (colon), NCI-H460 (lung) and U251 (glioblastoma) of the compounds (4a-4w) were evaluated. Introduction of heterocyclic amines in CAP region increased the enzyme inhibitory and antiproliferative activities and few of the compounds tested are metabolically stable in both MLM and HLM.

Thermodynamic properties of semiconductor compounds studied based on Debye-Waller factors

NASA Astrophysics Data System (ADS)

Van Hung, Nguyen; Toan, Nguyen Cong; Ba Duc, Nguyen; Vuong, Dinh Quoc

2015-08-01

Thermodynamic properties of semiconductor compounds have been studied based on Debye-Waller factors (DWFs) described by the mean square displacement (MSD) which has close relation with the mean square relative displacement (MSRD). Their analytical expressions have been derived based on the statistical moment method (SMM) and the empirical many-body Stillinger-Weber potentials. Numerical results for the MSDs of GaAs, GaP, InP, InSb, which have zinc-blende structure, are found to be in reasonable agreement with experiment and other theories. This paper shows that an elements value for MSD is dependent on the binary semiconductor compound within which it resides.

Effects of alkanolamide loading on swelling, rheometric and tensile properties of chloroprene rubber compounds

NASA Astrophysics Data System (ADS)

Surya, I.; Ismail, H.

2018-02-01

The effects of Alkanolamide (ALK) addition on swelling, rheometric and tensile properties of unfilled chloroprene rubber (CR) compounds were investigated. The ALK was prepared from Refined Bleached Deodorized Palm Stearin and diethanolamine and -together with magnesium and zinc oxides- incorporated into the CR compounds. The ALK loadings were 0.5, 1.0, 1.5 and 2.0 phr. It was found that ALK enhanced the cure rate and torque difference of the CR compounds. ALK also enhanced the tensile modulus and tensile strength; especially up to a 1.5 phr loading. The swelling test proved that the 1.5 phr of ALK exhibited the highest degree of crosslink density which caused the highest in tensile modulus and tensile strength.

Effects of soil type, prepercolation, and ageing on bioaccumulation and toxicity of zinc for the springtail Folsomia candida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smit, C.E.; Van Gestel, C.A.M.

1998-06-01

Soil properties are a major influence on the bioavailability and toxicity of metals and represent one of the important factors that complicate the extrapolation of results from laboratory tests to field situations. The influence of soil characteristics and way of contamination on the bioaccumulation and toxicity of zinc was investigated for the springtail Folsomia candida, and the applicability of chemical extraction techniques for the prediction of zinc uptake and toxicity was evaluated. Bioaccumulation of zinc in F. candida was related to water-soluble zinc concentrations, and uptake was dependent on the test soil used. Effects of zinc for F. candida couldmore » not be fully explained by bioaccumulation. This indicates that the existence of a fixed internal threshold concentration of zinc above which physiological functions are impaired is not likely for F. candida. In freshly contaminated soils, zinc toxicity was related to organic matter and clay content of the soil; however, the use of these soils overestimated the effects of zinc for F. candida by a factor of 5 to 8 compared to a test soil that was subjected to ageing under field conditions for 1.5 years. Equilibration of the zinc contamination by percolating the soils with water before use in the toxicity experiment strongly reduced the difference in zinc toxicity between laboratory-treated and aged soils. Water-soluble concentrations are most appropriate to predict effects of zinc on reproduction of F. candida in soils with unknown contamination histories. For laboratory toxicity tests, it is recommended to percolate soils with water after contamination and to include an equilibration period prior to use to achieve a more realistic exposure situation.« less

Assessment of intake inadequacy and food sources of zinc of people in China.

PubMed

Ma, Guansheng; Li, Yanping; Jin, Ying; Du, Songming; Kok, Frans J; Yang, Xiaoguang

2007-08-01

To assess the intake inadequacy and food sources of zinc of people in China. Diets of 68 962 subjects aged 2-101 years (urban 21 103, rural 47,859) in the 2002 China National Nutrition and Health Survey were analysed. Dietary intake was assessed using 24-hour recall for three consecutive days. Zinc intake inadequacy was calculated based on values suggested by the World Health Organization. The median zinc intake ranged from 4.9 mg day- 1 (urban girls, 2-3 years) to 11.9 mg day-1 (rural males, 19+ years). The zinc density of urban residents (2-3 to 19+ years) was 5.0-5.3 mg day-1 (1000 kcal)-1, significantly higher than that of their rural counterparts (4.7-4.8 mg day-1 (1000 kcal)-1). Differences in food sources of zinc from cereal grains (27.4-45.1 vs. 51.6-63.2%) and animal foods (28.4-54.8 vs. 16.8-30.6%) were found between urban and rural residents. Zinc from vegetables and fruits (8.2-13.8 vs. 9.7-12.4%) and legumes (1.3-3.3 vs. 2.5-3.4%) was comparable between urban and rural residents. The proportion of zinc intake inadequacy ranged between 2.8% (urban females, 19+ years) and 29.4% (rural lactating women). Rural residents had higher proportions of zinc intake inadequacy than their urban counterparts. Significantly higher proportions of zinc inadequacy were found in the category of phytate/zinc molar ratio >15 for both rural and urban residents. About 20% of rural children are at risk of inadequate zinc intake, with phytate as a potential important inhibitor. Moreover, lactating women are also considered a vulnerable group.

Survey of coatings for solar collectors. [ceramic enamels and chromium

NASA Technical Reports Server (NTRS)

Mcdonald, G. E.

1974-01-01

Ceramic enamel is found to be more solar selective, (i.e., has high solar absorptance in combination with low infrared emittance) than organic enamel, but neither is as solar selective as black chrome, black copper, black zinc, or black nickel. Ceramic enamel is matched only by black chrome in durability and wide availability. Ceramic enamel and organic enamel have approximately the same cost, and both are currently slightly lower in cost than black chrome, black copper, or black zinc. Black nickel is relatively unavailable and, because of that, realistic cost comparisons are not possible.

Use of zinc dust paints in shipbuilding as a prefabrication primer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakami, S.

1969-12-01

The widespread use of zinc dust paints and their economic advantages compared with the traditional methods of protecting steel from corrosion were described by speakers from the U.S., Japan, the Netherlands, Belgium, Norway, and the UK at a symposium organized by The Zinc Development Association. This, the newest method of applying metallic zinc coatings to steel, has grown enormously in popularity during the last 10 yr and has found many spectacular applications, such as for coating oil tankers of over 300,000 tons dwt, oil and sulfur rigs in the Gulf of Mexico, offshore oil-drilling wells in Alaska, as well asmore » for the more routine protection of bridges, railway rolling stock, and the steelwork of chemical and other industrial plants. A great amount of interest was shown in descriptions of satisfactory methods of welding steel coated with zinc-rich paints, and the simple ways in which health hazards from zinc fumes arising from welding can be avoided. It was stressed that zinc dust paints require good surface preparation, carefully controlled application, and properly engineered overcoating, but the comparatively high initial cost of achieving this is amply repaid in reduced maintenance in subsequent years.« less

Control of oral malodour by dentifrices measured by gas chromatography.

PubMed

Newby, Evelyn E; Hickling, Jenneth M; Hughes, Francis J; Proskin, Howard M; Bosma, Marylynn P

2008-04-01

To evaluate the effect of toothpaste treatments on levels of oral volatile sulphur compounds (VSCs) measured by gas chromatography in two clinical studies. These were blinded, randomised, controlled, crossover studies with 16 (study A) or 20 (study B) healthy volunteers between the ages of 19-54. Study A: breath samples were collected at baseline, immediately and lhr after brushing. Four dentifrices (Zinc A, Zinc B, commercially available triclosan dentifrice and zinc free control) were evaluated. Study B: breath samples were collected at baseline, immediately, 1, 2, 3 and 7 hours after treatment. Subjects consumed a light breakfast then provided an additional breath sample between baseline assessment and treatment. Two dentifrices (gel-to-foam and a commercially available triclosan dentrifrice) were evaluated. Breath samples were collected in syringes and analysed for VSCs (hydrogen sulphide, methyl mercaptan and Total VSCs) utilising gas chromatography (GC) with flame photometric detection. Study A: immediately after treatment, a statistically significant reduction in VSCs from baseline was observed for Zinc A product only. A statistically significant reduction in VSCs from baseline was observed after 1 hour for all products. Both zinc products exhibited a significantly greater reduction from baseline VSCs than Colgate Total and Control at all time points. Study B: a statistically significant reduction in VSCs from baseline was observed at all time points for both products. The gel-to-foam product exhibited significantly greater reduction from baseline Total VSC concentration than Colgate Total at all time points from 1 hour post-treatment. Control of oral malodour by toothpaste treatment, evaluated as VSC levels using GC, has been demonstrated. Zinc is effective at reducing VSCs and the efficacy of zinc is formulation dependent. A gel-to-foam dentifrice was more effective at reducing VSCs than Colgate Total up to 7 hours.

Two dimensional self-assembly zinc porphyrins and zinc phthalocyanines heterojunctions with record high power conversion efficiencies.

PubMed

Yu, Junting; Jiang, Zhou; Hao, Yifan; Zhu, Qianhong; Zhao, Mingliang; Jiang, Xue; Zhao, Jijun

2018-05-15

Compared to inorganic solar cells, the power conversion efficiencies (PCEs) of organic solar cells are much lower, but they are compensated by many merits such as lower cost, less weight, and tunable structures, making them prospective for further applications. Porphyrin and phthalocyanine are the two most significant materials for organic solar cells due to their strong light-absorbing properties and semiconductor characteristics. However, there is little research on the 2D heterojunction solar cells based on these two materials, meanwhile the PCEs of them are still low. Here we have self-assembled several 2D Zinc-porphyrins (ZnPors) and performed first-principles simulation to demonstrate their good stability, suitable light harvesting, and high charge carrier mobility. By perfectly matching lattice constants and band levels between those 2D ZnPors and our previous proposed ZnPcs, eleven type-II organic heterojunctions are constructed to further improve their charge separation capability. Those advantages endow 2D ZnPors and ZnPcs appreciable PCEs for solar cell. Among them, the theoretical PCE of 2D ZnPors/ZnPcs heterojunctions achieves as high as 19.84%, which prevails all reported organic solar cells, and even approaches the PCEs of inorganic solar cells. These results indicate that our 2D ZnPors and 2D ZnPcs are good candidate materials for future organic solar cells. © 2018 IOP Publishing Ltd.

Influence of solvents on the changes in structure, purity, and in vitro characteristics of green-synthesized ZnO nanoparticles from Costus igneus

NASA Astrophysics Data System (ADS)

Nandhini, G.; Suriyaprabha, R.; Maria Sheela Pauline, W.; Rajendran, V.; Aicher, Wilhelm Karl; Awitor, Oscar Komla

2018-05-01

The present study is intended to produce high-purity zinc oxide nanoparticles from the leaves of Costus igneus and zinc acetate precursor via sustainable methods by the tribulation with three different solvents (hot water, methanol, and acetone) for the extraction of plant compounds. While examining the physico-chemical characteristics of ZnO nanoparticles incurred by the catalysis of plant bioactive compounds extracted from different solvents, the hot water extract-based green synthesis process yields higher purity (99.89%) and smaller particle size (94 nm) than other solvents. The optimization of the solvents used for the green synthesis of nanoparticles renders key identification in appropriate extraction of bioactive compounds suitable for the nucleation/production of nanoparticles in addition to annealing temperature. The impregnable usage of ZnO nanoparticles in clinical applications is further confirmed based on the treatment of particles (1-10 mg ml-1) against Gram-positive (S. aureus and S. epidermis) and Gram-negative bacteria (E. coli and K. pneumoniae) with respect to their growth inhibition. An in-force growth inhibition against particular S. aureus and S. epidermis imparted by the low concentration of ZnO nanoparticles signifies the utilization and consumption of green-synthesized high-purity nanoparticles for therapeutic and cosmetic applications.

Surface coverage and corrosion inhibition effect of Rosmarinus officinalis and zinc oxide on the electrochemical performance of low carbon steel in dilute acid solutions

NASA Astrophysics Data System (ADS)

Loto, Roland Tolulope

2018-03-01

Electrochemical analysis of the corrosion inhibition and surface protection properties of the combined admixture of Rosmarinus officinalis and zinc oxide on low carbon steel in 1 M HCl and H2SO4 solution was studied by potentiodynamic polarization, open circuit potential measurement, optical microscopy and ATR-FTIR spectroscopy. Results obtained confirmed the compound to be more effective in HCl solution, with optimal inhibition efficiencies of 93.26% in HCl and 87.7% in H2SO4 acid solutions with mixed type inhibition behavior in both acids. The compound shifts the corrosion potential values of the steel cathodically in HCl and anodically in H2SO4 signifying specific corrosion inhibition behavior without applied potential. Identified functional groups of alcohols, phenols, 1°, 2° amines, amides, carbonyls (general), esters, saturated aliphatic, carboxylic acids, ethers, aliphatic amines, alkenes, aromatics, alkyl halides and alkynes within the compound completely adsorbed onto the steel forming a protective covering. Thermodynamic calculations showed physisorption molecular interaction with the steel's surface according to Langmuir and Frumkin adsorption isotherms. Optical microscopy images of the inhibited and uninhibited steels contrast each other with steel specimens from HCl solution showing a better morphology.

Organic-Free, ZnO-Assisted Synthesis of Zeolite FAU with Tunable SiO2 /Al2 O3 Molar Ratio.

PubMed

Guo, Ya; Sun, Tianjun; Gu, Yiming; Liu, Xiaowei; Ke, Quanli; Wang, Shudong

2018-05-04

Zeolite FAU with tunable SiO 2 /Al 2 O 3 molar ratio has been successfully synthesized in the absence of organic structure-directing agents (OSDA). Specifically, the addition of zinc species contributes to the feasible and effective adjustment of the framework SiO 2 /Al 2 O 3 molar ratio between about 4 and 6 depending on the amount of zinc species added in the batch composition. In contrast, a typical OSDA such as tetramethylammonium hydroxide (TMAOH) has a limited effect on the SiO 2 /Al 2 O 3 molar ratio of the zeolite. The role of zinc species is essential for the crystallization of zeolite FAU with a higher SiO 2 /Al 2 O 3 molar ratio under the particular synthesis conditions. It is speculated that zinc species may suppress the incorporation of aluminum into the aluminosilicate framework, which is due to the Coulombic repulsive interaction. A higher SiO 2 /Al 2 O 3 molar ratio is also found to be accompanied by a lower CO 2 adsorption heat for CO 2 /CH 4 separation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Armeria maritima from a calamine heap--initial studies on physiologic-metabolic adaptations to metal-enriched soil.

PubMed

Olko, A; Abratowska, A; Zyłkowska, J; Wierzbicka, M; Tukiendorf, A

2008-02-01

Plants of Armeria maritima are found both on unpolluted sites and on soils strongly polluted with heavy metals. Seedlings of A. maritima from a zinc-lead calamine heap in ore-mining region (Bolesław population) and from unpolluted area (Manasterz population) were tested to determine the zinc, cadmium and lead tolerance. In hydroponic experiments Bolesław population was more tolerant to zinc, cadmium and lead. Localization of heavy metals in roots was determined using the histochemical method for detecting metal-complexes with dithizone. Their accumulation was found in root hairs, rhizoderma and at the surface of the central cylinder. Glutathione level in plants increased after metal treatment of both populations. However, its high level was not correlated with phytochelatin production. These metal-binding complexes were not detected in plants exposed to zinc, cadmium or lead. Changes of organic acids concentrations in Armeria treated with metals may suggest their role in metal translocation from roots to shoots. The content of organic acids, especially malate, decreased in the roots and increased in the leaves. These changes may be important in Pb-tolerance of Manasterz population and in Zn-, Cd-tolerance of calamine population from Bolesław.

Facile Route to Rare Heterobimetallic Aluminum-Copper and Aluminum-Zinc Selenide Clusters.

PubMed

Li, Bin; Li, Jiancheng; Liu, Rui; Zhu, Hongping; Roesky, Herbert W

2017-03-20

Heterobimetallic aluminum-copper and aluminum-zinc clusters were prepared from the reaction of LAl(SeH) 2 [1; L = HC(CMeNAr) 2 and Ar = 2,6-iPr 2 C 6 H 3 ] with (MesCu) 4 and ZnEt 2 , respectively. The resulting clusters with the core structures of Al 2 Se 4 Cu 4 and Al 2 Se 4 Zn 3 exhibit unique metal-organic frameworks. This is a novel pathway for the synthesis of aluminum-copper and aluminum-zinc selenides. The products have been characterized by spectroscopic methods and single-crystal X-ray structural characterization.

Zinc transport in rabbit tissues. Some hormonal aspects of the turnover of zinc in female reproductive organs, liver and body fluids

PubMed Central

McIntosh, J. E. A.; Lutwak-Mann, C.

1972-01-01

1. To investigate the influence of hormonal conditions upon the kinetics of zinc transport, specific radioactivity of 65Zn was determined in certain tissues and fluids from unmated or pregnant rabbits during the first half of gestation. 2. Compartmental analysis was used to find the simplest mathematical model that simulated satisfactorily tracer behaviour. Models were fitted to experimental results by a numerical procedure using a computer. 3. The kinetics of zinc exchange in most tissues investigated could adequately be described by a three-compartment model, in which total tissue zinc content was divided into a rapidly exchanging pool, with a turnover time of about 1h, and a slowly exchanging pool, the turnover time of which was in liver 15h, in peak-stage corpus luteum 8h, and in the other tissues 30–70h. 4. In rabbit endometrium zinc transport varied with hormonal conditions, the turnover rate being higher in non-pregnant than pregnant endometrium. 5. Uptake of 65Zn by uterine fluid was slow, and in the free-lying embryos (blastocysts) slower still, in keeping with uterine fluid acting as carrier of zinc into the unimplanted embryos. 6. In placental tissue zinc transport varied with gestational stage. Foetal placenta exchanged zinc with blood plasma four times faster than maternal placenta. In foetuses zinc turnover time and flux equalled that of the slow zinc compartment in foetal placenta. 7. Corpus luteum on days 5–6 of gestation showed peak specific radioactivity and zinc flux values, which exceeded those of all other tissues. 8. In liver the slow zinc compartment had a higher rate of turnover than corresponding compartments in tissues other than peak-stage corpus luteum, but no hormone-dependent changes were observed. 9. Zinc uptake by erythrocytes was the slowest of all examined. PMID:5073239