Showing papers on "Zinc published in 2011"
TL;DR: In this paper, the synthesis of nanostructured zinc oxide nanoparticles by both chemical and biological method was reported, and the results showed that the particles obtained were poly dispersed and the average size ranged from 25 to 40nm.
758 citations
TL;DR: Water chemistry can be a major factor regulating the toxicity mechanism of ZnO nanoparticles (nano-ZnO) in water and the effect of water chemistry on the physicochemical properties of nanoparticles should be paid more attention in future nanotoxicity evaluations.
Abstract: Water chemistry can be a major factor regulating the toxicity mechanism of ZnO nanoparticles (nano-ZnO) in water. The effect of five commonly used aqueous media with various chemical properties on ...
677 citations
TL;DR: The corrosion rates of the Zn-Mg alloys were determined to be significantly lower than those of Mg and AZ91HP alloys and possible zinc doses and toxicity were estimated from the corrosion behavior of the zinc alloys.
503 citations
TL;DR: This review addresses recent findings regarding Zn signaling and its role in physiological processes and pathogenesis and proposes that intracellular ZN signaling falls into two classes, early and late Zn signaled.
Abstract: The essential trace element zinc (Zn) is widely required in cellular functions, and abnormal Zn homeostasis causes a variety of health problems that include growth retardation, immunodeficiency, hypogonadism, and neuronal and sensory dysfunctions. Zn homeostasis is regulated through Zn transporters, permeable channels, and metallothioneins. Recent studies highlight Zn’s dynamic activity and its role as a signaling mediator. Zn acts as an intracellular signaling molecule, capable of communicating between cells, converting extracellular stimuli to intracellular signals, and controlling intracellular events. We have proposed that intracellular Zn signaling falls into two classes, early and late Zn signaling. This review addresses recent findings regarding Zn signaling and its role in physiological processes and pathogenesis.
486 citations
TL;DR: The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.
Abstract: Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.
447 citations
TL;DR: In this article, plate-shaped zinc oxide nanoparticles (ZnO-NPs) were successfully synthesized by a modified sol-gel combustion method, where zinc acetate, pure water and isopropanol were used as the starting materials.
390 citations
TL;DR: The results confirm that TEA is a suitable polymer agent to prepare homogenous ZnO-NPs.
Abstract: Zinc oxide nanoparticles (ZnO-NPs) were synthesized via a solvothermal method in triethanolamine (TEA) media. TEA was utilized as a polymer agent to terminate the growth of ZnO-NPs. The ZnO-NPs were characterized by a number of techniques, including X-ray diffraction analysis, transition electron microscopy, and field emission electron microscopy. The ZnO-NPs prepared by the solvothermal process at 150°C for 18 hours exhibited a hexagonal (wurtzite) structure, with a crystalline size of 33 ± 2 nm, and particle size of 48 ± 7 nm. The results confirm that TEA is a suitable polymer agent to prepare homogenous ZnO-NPs.
370 citations
TL;DR: The human body has an elaborate system for managing and regulating the amount of key trace metals circulating in blood and stored in cells, but when this system fails to function properly, abnormal levels and ratios of trace metals can develop.
Abstract: The human body has an elaborate system for managing and regulating the amount of key trace metals circulating in blood and stored in cells. Nutrient metals from our diet are incorporated into blood if blood levels are depleted, transported into cells if cellular levels are inadequate, or excreted if blood and cell levels are sufficient or overloaded. When this system fails to function properly, abnormal levels and ratios of trace metals can develop. One of the most common trace-metal imbalances is elevated copper and depressed zinc. The ratio of copper to zinc is clinically more important than the concentration of either of these trace metals [1]. There are 2-4 grams of Zn distributed throughout the human body [2]. Most zinc is in the brain, muscle, bones, kidney and liver, with the highest concentrations in the prostate and parts of the eye [3]. It is the second most abundant transition metal in organisms after iron and it is the only metal which appears in all enzyme classes [2,4]. Copper is also a vital dietary nutrient, although only small amounts of the metal are needed for well-being [5]. Although copper is the third most abundant trace metal in the body [behind iron and zinc], the total amount of copper in the body is only 75-100 milligrams [6]. Copper is present in every tissue of the body, but is stored primarily in the liver, with fewer amounts found in the brain, heart, kidney, and muscles.
368 citations
TL;DR: An automated biogeochemical microcosm system allowing the control of redox potential (E H ) in soil suspensions was used to assess the effect of E H on the mobility of cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn), iron (Fe), and manganese (Mn) as well as on the methylation of arsenic (As) and antimony (Sb) in a contaminated and slightly acidic floodplain soil as discussed by the authors.
345 citations
TL;DR: In this article, a green method is reported to effectively and rapidly reduce graphene oxide to graphene with zinc powder at room temperature, which is carried out by mixing graphene oxide and zinc powder in solution under ultrasonication.
343 citations
TL;DR: In this paper, zinc oxide was combined with iron oxide to produce magnetic composite nanoparticles with improved colloidal aqueous stability, together with adequate antibacterial activity, which were synthesized by basic hydrolysis of Feµµ and Znµ ions in aquequeous continuous phase containing gelatin.
Centre national de la recherche scientifique1, Paul Sabatier University2, Aix-Marseille University3, French Institute of Health and Medical Research4, Fudan University5, Pasteur Institute6, Brighton and Sussex Medical School7, University of Milano-Bicocca8, St George's, University of London9, Singapore Immunology Network10
TL;DR: The use of P1-type ATPases represents a M. tuberculosis strategy to neutralize the toxic effects of zinc in macrophages, suggesting that heavy metal toxicity and its counteraction might represent yet another chapter in the host-microbe arms race.
TL;DR: Biomarkers of metabolic zinc redistribution are needed to determine whether this redistribution of zinc from the plasma to the tissues is the cause of a low plasma zinc rather than poor nutrition.
TL;DR: In this paper, ordered layered double hydroxides (LDHs) consisting of zinc and/or copper hydroxide were synthesized and combined with aluminum or gallium to convert gaseous CO2 to methanol or CO under UV-visible light using hydrogen.
TL;DR: In this article, the photoluminescence spectra have identified several kinds of defects in as-synthesized ZnO materials, such as oxygen vacancy (Vo), zinc vacancy (VZn) and interstitial zinc (Zni), and the activity evaluation and kinetic calculation show that the samples with higher relative content of oxygen vacancy possess larger reaction rate constant and higher catalytic activity for Rhodamine B photodegradation.
Abstract: The flower-like ZnO materials were hydrothermally synthesized with or without ultrasonic assistance. When low dosage of citric acid is used, ultrasonic treatment can enhance the distribution and complexation of Zn ions; the formed complicated citrates can serve as soft template directing the formation of seaweed-like ZnO/Zn(OH)2 precursor; this precursor with citrates attaching on it serves as hard template for the formation of regular flower-like ZnO in the hydrothermal condition. The photoluminescence spectra have identified several kinds of defects in as-synthesized ZnO materials, such as oxygen vacancy (Vo), zinc vacancy (VZn) and interstitial zinc (Zni). The activity evaluation and kinetic calculation show that the samples with higher relative content of oxygen vacancy possess larger reaction rate constant and higher catalytic activity for Rhodamine B photodegradation. The employment of ultrasonic treatment during preparation decreases the relative content of oxygen vacancy, thus suppressing green emission and reducing the photocatalytic activity of such flower-like ZnO.
TL;DR: In this paper, the authors studied the photocatalytic activity of ZnO tetrapods and different types of nanoparticles, and found that nanoparticles with small particle size exhibited higher Brunauer-Emmett-Teller (BET) coefficients.
Abstract: We have studied the photocatalytic activity of ZnO tetrapods, ZnO powder, and different ZnO nanoparticles. While nanoparticles with small particle size exhibited higher Brunauer–Emmett–Teller (BET)...
TL;DR: This review highlights studies on both combustion-derived NP- and manufactured or engineered NP-induced neuroinflammation, oxidative stress, and gene expression, as well as the possible mechanism of these effects in animal models and in humans.
Abstract: Humans are exposed to nanoparticles (NPs; diameter < 100 nm) from ambient air and certain workplaces. There are two main types of NPs; combustion-derived NPs (e.g., particulate matters, diesel exhaust particles, welding fumes) and manufactured or engineered NPs (e.g., titanium dioxide, carbon black, carbon nanotubes, silver, zinc oxide, copper oxide). Recently, there have been increasing reports indicating that inhaled NPs can reach the brain and may be associated with neurodegeneration. It is necessary to evaluate the potential toxic effects of NPs on brain because most of the neurobehavioral disorders may be of environmental origin. This review highlights studies on both combustion-derived NP- and manufactured or engineered NP-induced neuroinflammation, oxidative stress, and gene expression, as well as the possible mechanism of these effects in animal models and in humans.
TL;DR: Electrochemical techniques, quantum chemical calculations, and steady-state and femtosecond spectroscopy were employed to establish a photophysical mechanism for this phosphorescence response and revealed that zinc coordination perturbs nonemissive processes of photoinduced electron transfer and intraligand charge-transfer transition occurring between DPA and phen.
Abstract: A new phosphorescent zinc sensor (ZIrF) was constructed, based on an Ir(III) complex bearing two 2-(2,4-difluorophenyl)pyridine (dfppy) cyclometalating ligands and a neutral 1,10-phenanthroline (phen) ligand. A zinc-specific di(2-picolyl)amine (DPA) receptor was introduced at the 4-position of the phen ligand via a methylene linker. The cationic Ir(III) complex exhibited dual phosphorescence bands in CH(3)CN solutions originating from blue and yellow emission of the dfppy and phen ligands, respectively. Zinc coordination selectively enhanced the latter, affording a phosphorescence ratiometric response. Electrochemical techniques, quantum chemical calculations, and steady-state and femtosecond spectroscopy were employed to establish a photophysical mechanism for this phosphorescence response. The studies revealed that zinc coordination perturbs nonemissive processes of photoinduced electron transfer and intraligand charge-transfer transition occurring between DPA and phen. ZIrF can detect zinc ions in a reversible and selective manner in buffered solution (pH 7.0, 25 mM PIPES) with K(d) = 11 nM and pK(a) = 4.16. Enhanced signal-to-noise ratios were achieved by time-gated acquisition of long-lived phosphorescence signals. The sensor was applied to image biological free zinc ions in live A549 cells by confocal laser scanning microscopy. A fluorescence lifetime imaging microscope detected an increase in photoluminescence lifetime for zinc-treated A549 cells as compared to controls. ZIrF is the first successful phosphorescent sensor that detects zinc ions in biological samples.
TL;DR: The overall results suggest that toxicity studies assessing the effects of nanoparticles on aquatic organisms need to consider both the dissolution of these particles and the cellular interaction of nanoparticle aggregates.
TL;DR: The performance of a divided, parallel-plate zinc-cerium redox flow battery using methaneulfonic acid electrolytes was studied in this article, where eight two and three-dimensional electrodes were tested under both constant current density and constant cell voltage discharge.
TL;DR: This review focuses on the biological roles of iron, copper, zinc, manganese, nickel and cobalt, the homeostatic mechanisms that function in S. cerevisiae and the human diseases in which these metals have been implicated.
Abstract: Transition metal ions are essential nutrients to all forms of life. Iron, copper, zinc, manganese, cobalt and nickel all have unique chemical and physical properties that make them attractive molecules for use in biological systems. Many of these same properties that allow these metals to provide essential biochemical activities and structural motifs to a multitude of proteins including enzymes and other cellular constituents also lead to a potential for cytotoxicity. Organisms have been required to evolve a number of systems for the efficient uptake, intracellular transport, protein loading and storage of metal ions to ensure that the needs of the cells can be met while minimizing the associated toxic effects. Disruptions in the cellular systems for handling transition metals are observed as a number of diseases ranging from hemochromatosis and anemias to neurodegenerative disorders including Alzheimer’s and Parkinson’s disease. The yeast Saccharomyces cerevisiae has proved useful as a model organism for the investigation of these processes and many of the genes and biological systems that function in yeast metal homeostasis are conserved throughout eukaryotes to humans. This review focuses on the biological roles of iron, copper, zinc, manganese, nickel and cobalt, the homeostatic mechanisms that function in S. cerevisiae and the human diseases in which these metals have been implicated.
TL;DR: The presence of Zn in the vascular system of roots and leaves in ZnO NP treated plants was confirmed by the μXRF analysis.
TL;DR: It is demonstrated previously that an axial LF, whereby donor atoms with higher negative charges are located along the principal axis, induces a strong Ising-type anisotropy of Tb and Dy ions, which has a wide scope in the synthetic design of anisotropic magnets.
Abstract: Single-molecule magnets (SMMs) are chemically and physically interesting compounds that exhibit hitherto unobserved magnetic properties. To prevent reversal of the molecular magnetic moment, the use of heavy lanthanide ions is becoming popular because of their large spin multiplicity and large magnetic anisotropies in the ground state. Lanthanide ions exhibit flexibility in magnetic anisotropy, which is another advantage of Ln-based SMMs that is attributable to the flexible design and control of the ligandfield (LF) anisotropy. These anisotropies are correlated through Stevens factor qm as B n m 1⁄4 Am r h iqm, where Bm denotes the mth-order magnetic anisotropy parameters (m is 2, 4, or 6 for lanthanide ions; n varies between 0 and m ; second-order terms of B2 and B 2 2 correspond to the axial and rhombic anisotropic parameters D and E), and Am r m h i denotes the LF anisotropy parameters. Therefore, Ln complexes have a wide scope in the synthetic design of anisotropic magnets. Although many complexes including one or more heavy lanthanide ions are reported to be SMMs, most of them were synthesized in a fortuitous manner without design of the magnetic anisotropy. We have demonstrated previously that an axial LF, whereby donor atoms with higher negative charges are located along the principal axis, induces a strong Ising-type anisotropy of Tb and Dy ions. This type of LF anisotropy is easily achieved in an accidental manner, and thus a wide variety of Tb and Dy SMMs have been reported. On the contrary, Er-based SMMs are rare. When the second-order anisotropy terms are dominant, magnetic anisotropy of the Er ion has opposite features to those of Tb and Dy ions, since the q2 parameter of the Er III
TL;DR: In this article, transparent conducting aluminium doped zinc oxide (ZnO:Al ) thin films were deposited on float glass substrates by tailor made spray pyrolysis with adaptation for measuring the actual temperature of the substrate surface during deposition.
TL;DR: These new findings establish critically important functions of zinc ions and zinc metalloproteins in cellular control and their generation, transmission, targets, and termination.
Abstract: Homeostatic control maintains essential transition metal ions at characteristic cellular concentrations to support their physiological functions and to avoid adverse effects. Zinc is especially widely used as a catalytic or structural cofactor in about 3000 human zinc proteins. In addition, the homeostatic control of zinc in eukaryotic cells permits functions of zinc(II) ions in regulation and in paracrine and intracrine signaling. Zinc ions are released from proteins through ligand-centered reactions in zinc/thiolate coordination environments, and from stores in cellular organelles, where zinc transporters participate in zinc loading and release. Muffling reactions allow zinc ions to serve as signaling ions (second messengers) in the cytosol that is buffered to picomolar zinc ion concentrations at steady-state. Muffling includes zinc ion binding to metallothioneins, cellular translocations of metallothioneins, delivery of zinc ions to transporter proteins, and zinc ion fluxes through cellular membranes with the result of removing the additional zinc ions from the cytosol and restoring the steady-state. Targets of regulatory zinc ions are proteins with sites for transient zinc binding, such as membrane receptors, enzymes, protein-protein interactions, and sensor proteins that control gene expression. The generation, transmission, targets, and termination of zinc ion signals involve proteins that use coordination dynamics in the inner and outer ligand spheres to control metal ion association and dissociation. These new findings establish critically important functions of zinc ions and zinc metalloproteins in cellular control.
TL;DR: The data indicates cyto- and genotoxic properties as well as a pro-inflammatory potential of ZnO-NPs in nasal mucosa cells, and caution should be taken concerning their industrial and dermatological application.
TL;DR: In this article, the authors carried out a comparative study on ZnO thin films prepared using both sol-gel and molecular beam epitaxy (MBE) methods, and they found that the solgel derived samples showed much stronger room temperature ferromagnetism with a magnetic signal persisting up to ∼740 K, and this ferromagnetic order coexists with a high density of defects in the form of zinc vacancies.
Abstract: To shed light on the mechanism responsible for the weak ferromagnetism in undoped wide band gap oxides, we carry out a comparative study on ZnO thin films prepared using both sol-gel and molecular beam epitaxy (MBE) methods. Compared with the MBE samples, the sol-gel derived samples show much stronger room temperature ferromagnetism with a magnetic signal persisting up to ∼740 K, and this ferromagnetic order coexists with a high density of defects in the form of zinc vacancies. The donor-acceptor pairs associated with the zinc vacancies also cause a characteristic orange-red photoluminescence in the sol-gel films. Furthermore, the strong correlation between the ferromagnetism and the zinc vacancies is confirmed by our first-principles density functional theory calculations, and electronic band alteration as a result of defect engineering is proposed to play the critical role in stabilizing the long-range ferromagnetism.
TL;DR: In this paper, the physicochemical properties of different corrosion products are compared and a preferential dissolution of Zn and Mg at initial stages of corrosion is confirmed by in situ dissolution measurement.