Zinc Research Papers - Academia.edu (original) (raw)

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- Dentistry, Treatment Outcome, Dental Materials, Soil Cementation

A new phthalonitrile derivative with two different substituents on 4-and 5-positions has been synthesized and its cyclotetramerization in the presence of anhydrous metal salts without any solvent resulted with phthalocyanines (4e6) containing a hexylthio group and malonylester on each benzo unit. When phthalocyanine formation was carried out in high-boiling alcohols in the presence of a base transesterification of malonyl esters gave products with enhanced solubility in apolar solvents. These new compounds have been characterized by 1 H NMR, FT-IR, UVevis and mass spectroscopies.

- by Ahmet Gül
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- Chemical Engineering, Copper, Zinc, Mass Spectroscopy
- by Ludo Diels
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- Technology, Biotechnology, Biomass, Biological Sciences

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents. The assessment of the metal-binding capacity of some new biosorbents is discussed. Lead and cadmium, for instance, have been effectively removed from very dilute solutions by the dried biomass of some ubiquitous species of brown marine algae such as Ascophyllum and Sargassum, which accumulate more than 30% of biomass dry weight in the metal. Mycelia of the industrial steroidtransforming fungi Rhizopus and Absidia are excellent biosorbents for lead, cadmium, copper, zinc, and uranium and also bind other heavy metals up to 25% of the biomass dry weight. Biosorption isotherm curves, derived from equilibrium batch sorption experiments, are used in the evaluation of metal uptake by different biosorbents. Further studies are focusing on the assessment of biosorbent performance in dynamic continuous-flow sorption systems. In the course of this work, new methodologies are being developed that are aimed a t mathematical modeling of biosorption systems and their effective optimization. Elucidation of mechanisms active in metal biosorption is essential for successful exploitation of the phenomenon and for regeneration of biosorbent materials in multiple reuse cycles. The complex nature of biosorbent materials makes this task particularly challenging. Discussion focuses on the composition of marine algae polysaccharide structures, which seem instrumental in metal uptake and binding. The state of the art in the field of biosorption is reviewed in this article, with many references to recent reviews and key individual contributions. A Bohumil Volesky is a Professor of Chemical Engineering a t McGill University (Montreal, Canada), active in areas of biochemical engineering and industrial water pollution control. He obtained his basic training a t the Czech Technical University in Prague, Czech Republic, receiving the Dipl. Ing. degree in 1962. Following more than 4 years of industrial research and experience, he earned his Ph.D. in biochemical engineering a t the University of Western Ontario (London, Ontario) in 1971. He is the founder and a president of BV Sorbex, Inc., a new technology venture commercializing the biosorption process for removal and recovery of heav metals from industrial solutions that he has been pioneering in his research. He has held appointments as a visiting professor a t the Swiss Federal Institute of Technology (Lausanne, Switzerland) and a t the University of Puerto Rico, and his major collaborative research activities include colleagues in China, Brazil, Korea, and the Czech Republic. His current research interests are reflected in a recently published book Biosorption of Heavy Metals that he edited and in a monograph volume Modeling and Optimization of Fermentation Processes. t 4

- by E Z
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- Engineering, Environmental Science, Technology, Biomass

ZnO nanoparticles have been synthesized by ultrasonic irradiation of an aqueous-alcoholic/aqueous-alcoholic-ethylenediamine (EDA) solutions of zinc nitrate and sodium hydroxide. ZnO nanoparticles possess hexagonal wurtzite structures and they exhibit special photoluminescence properties with a red-shift of 22 nm in UV emission band. It is found that the ultrasonic irradiation time and the solvents both influence the growth mechanism and optical properties of ZnO nanoparticles. The possible growth mechanism of ZnO nanoparticles formation by sonochemical method has been tried to discuss.

- by avinash chandra pandey
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- Nanoparticle, Ultrasound, Sonochemistry, Zinc

To understand the interactions between iron and zinc during absorption in iron- and zinc-deficient rats, and their consequences on intestinal oxidant-antioxidant balance. Twenty-four weanling Wistar-Kyoto rats fed an iron- and zinc-deficient diet (< 6.5 mg Fe and 4.0 mg Zn/kg diet) for 4 wk were randomly divided into three groups (n = 8, each) and orally gavaged with 4 mg iron, 3.3 mg zinc, or 4 mg iron + 3.3 mg zinc for 2 wk. At the last day of repletion, 3 h before the animals were sacrificed, they received either 37 mBq of (55)Fe or (65)Zn, to study their localization in the intestine, using microautoradiography. Hemoglobin, iron and zinc content in plasma and liver were measured as indicators of iron and zinc status. Duodenal sections were used for immunochemical staining of ferritin and metallothionein. Duodenal homogenates (mitochondrial and cytosolic fractions), were used to assess aconitase activity, oxidative stress, functional integrity and the response of antioxidant e...

- by Krishnapillai Nair
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- Oxidative Stress, Intestinal Mucosa, Glutathione Peroxidase, Zinc

Approximately 3% of infants born have at least one serious congenital malformation. In the U.S., an average of 10 infants per thousand die before 1 y of life; about half of these deaths can be attributed to birth defects, low birth weight or prematurity. Although the causes of developmental abnormalities are clearly multifactorial in nature, we suggest that a common factor contributing to the occurrence of developmental abnormalities is suboptimal mineral nutrition during embryonic and fetal development. Using zinc and copper as examples, evidence is presented that nutritional deficiencies can rapidly affect the developing conceptus and result in gross structural abnormalities. Deficits of zinc or copper can result in rapid changes in cellular redox balance, tissue oxidative stress, inappropriate patterns of cell death, alterations in the migration of neural crest cells and changes in the expression of key patterning genes. In addition to well-recognized malformations, mineral deficiencies during perinatal development can result in behavioral, immunological and biochemical abnormalities that persist into adulthood. Although these persistent defects can in part be attributed to subtle morphological abnormalities, in other cases they may be secondary to epigenetic or developmental changes in DNA methylation patterns. Epigenetic defects combined with subtle morphological abnormalities can influence an individual's risk for certain chronic diseases and thus influence his or her risk for morbidity and mortality later in life.

- by Robert Rucker
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- Nutrition and Dietetics, Nutrition, Reproduction, Aging

Human insulin exists in different association states, from monomer to hexamer, depending on the conditions. In the presence of zinc the ''normal'' state is a hexamer. The structural properties of 20 variants of human insulin were studied by near-UV circular dichroism, fluorescence spectroscopy, and small-angle X-ray scattering (SAXS). The mutants showed different degrees of association (monomer, dimers, tetramers, and hexamers) at neutral pH. A correlation was shown between the accessibility of tyrosines to acrylamide quenching and the degree of association of the insulin mutants. The near-UV CD spectra of the insulins were affected by protein association and by mutation-induced structural perturbations. However, the shape and intensity of difference CD spectra, obtained by subtraction of the spectra measured in 20% acetic acid (where all insulin species were monomeric) from the corresponding spectra measured at neutral pH, correlate well with the degree of insulin association. In fact, the near-UV CD difference spectra for monomeric, dimeric, tetrameric, and hexameric insulin are very distinctive, both in terms of intensity and shape. The results show that the spectral properties of the insulins reflect their state of association, and can be used to predict their oligomeric state.

- by Sven Frokjaer
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- Fluorescence Spectroscopy, Fluorescence, Prediction, Small Angle X Ray Scattering

Objectives: Diarrhoeal diseases (DDs) constitute public health problem. Reduction in related mortality and morbidity hinges on active participation of home caregivers. It is pertinent to determine the degree of their empowerment. Design: Cross-sectional study. Setting: Randomly selected community primary health centres in northwestern Nigerian. Subjects: Home caregivers presenting with children aged 1-59 months having DD. Outcome measures: Knowledge, attitude and practice regards home management of DD. Results: Less than 1% of caregivers was knowledgeable about home management of DD. Antibiotics and anti-diarrhoeal agents use was common at 36%. ORS use was abysmally low at 8.6%. Only 32% of caregivers were aware of the use of zinc in the management of DD. Adherence to 10-day zinc supplementation was encouraging at 75.5%. Conclusion: There is an urgent need to scale up educational and promotional activities with regards to the home management of DD if the millennium development goals are to be met.

- by Olumuyiwa Owolabi
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- Nigeria, Diarrhea, Infant, Zinc

Sea-water samples collected by a variety of clean sampling techniques yielded consistent results for copper, cadmium, zinc, and nickel, which implies that representative, uncontaminated samples were obtained. A dithiocarbamate extraction method coupled with atomic absorption spectrometry and electro,thermal atomization is described which is essentially 100% quantitative for each of the four metals studied, has lower blanks and detection limits, and yields better precision than previously published techniques. A more precise and accurate determination of these metals in sea water at their natural ng 1-l concentration levels is therefore possible. Samples analyzed by this procedure and by concentration on Chelex-100 showed similar results for cadmium and zinc. Both copper and nickel appeared to be inefficiently removed from sea water by Chelex-100. Comparison of the organic extraction results with other pertinent investigations showed excellent agreement.

- by Kenneth Bruland
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- Analytical Chemistry, Copper, Zinc, Nickel

Gold nanoparticles protected by a binary mixture of thiolate molecules have a ligand shell that can spontaneously separate into nanoscale domains. Complex morphologies arise in such ligand shells, including striped, patchy, and Janus domains. Characterization of these morphologies remains a challenge. Scanning tunneling microscopy (STM) imaging has been one of the key approaches to determine these structures, yet the imaging of nanoparticles' surfaces faces difficulty stemming from steep surface curvature, complex molecular structures, and the possibility of imaging artifacts in the same size range. Images obtained to date have lacked molecular resolution, and only domains have been resolved. There is a clear need for images that resolve the molecular arrangement that leads to domain formation on the ligand shell of these particles. Herein we report an advance in the STM imaging of gold nanoparticles, revealing some of the molecules that constitute the domains in striped and Janus gold nanoparticles. We analyze the images to determine molecular arrangements on parts of the particles, highlight molecular "defects" present in the ligand shell, show persistence of the features across subsequent images, and observe the transition from quasimolecular to domain resolution. The ability to resolve single molecules in the ligand shell of nanoparticles could lead to a more comprehensive understanding of the role of the ligand structure in determining the properties of mixed-monolayer-protected gold nanoparticles.

- by Sofia Deloudi
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- Engineering, Materials Engineering, Condensed Matter Physics, Quantum Physics

Surface oxide films were grown on 99.99% copper and brass (copper-zinc alloy, Cu77Zn21Al2) in 0.1 mol L −1 borax solution at open circuit potential and were characterized using various experimental techniques. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. The thickness of the oxide layers on copper and brass was compared by chronopotentiometric curves and potentiodynamic reductions. The electrical properties of each oxide were analyzed by means of electrochemical impedance spectroscopy. Their influence on the oxygen reduction reaction was also investigated using voltammetry hydrodynamic tools such as the rotating disk electrode. The results show that the incorporation of Zn to Cu in brass changes the composition and the thickness of the surface film. The films grown on brass tend to be thicker but less resistive and Zn compounds incorporate to the film. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction is strongly inhibited on oxidized electrodes, particularly in the case of brass. The global number of exchanged electrons remains close to four and seems to be independent of the presence of surface oxides. .ar (S. Ceré). circuit potential and the relationship between the oxidized surface and the oxygen reduction reaction.

- by Silvia cere
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- Engineering, Kinetics, Impedance Spectroscopy, Electrochemical Impedance Spectroscopy

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full... more

- by marioara nechifor
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- Zinc, Condensation Reactions

Dimensional reduction of ZnO semiconductors is expected to create wide-ranging application possibilities from roomtemperature ultraviolet (UV) lasers, sensors, photocatalysts, solar cells, [4] to field-emission (FE) devices. In general, ZnO nanowires as one-dimensional (1D) materials with diameters of less than 10 nm are expected to display novel and unique physical and chemical properties due to quantum confinement. Furthermore, it is very important to fabricate a dense array of ZnO nanowires on an appropriate substrate so that the nanowires can be directly addressed, surface area can be optimized, and/or collective properties may be induced. A host of techniques have been developed for the synthesis of aligned 1D ZnO nanostructures with sizes in the range of 10-100 nm on a variety of substrates for nanodevice applications. [6] For example, well-aligned ZnO nanowires that are 10-15 nm across have been grown from patterned, thin gold dots on sapphire substrates by a vapor-liquid-solid (VLS) process. To our knowledge, however, little has been reported on the synthesis of well-aligned ZnO nanowires with diameters of less than 10 nm. Although 6nm ZnO nanobelts have been obtained by solid-vapor deposition, [9] they are randomly oriented. Therefore, one of the synthetic challenges of nanowire materials is to reduce the nanowire diameter and, at the same time, align the nanowires in a controlled fashion. Here, we demonstrate the first synthesis of aligned ZnO nanofibers, which are no thicker than 10 nm and % 500 nm in length, by hydrothermal treatment of a Zn foil in an ammonia/alcohol aqueous solution. It should be emphasized that the reaction was carried out at a relatively low temperature without any catalyst. We have established that the use of ammonia/alcohol is crucial to the growth of the aligned ultrathin ZnO nanofibers. Photoluminescence (PL) measurement at room temperature shows a prominent peak at 373 nm (3.32 eV), which is about 100 meV blue-shifted from the bulk ZnO emission (3.24 eV, 383 nm) due to the ultrafine dimension along the radial direction of the ZnO nanofibers.

- by Jiannong Wang
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- Nanofibers, Crystallization, Nanotechnology, Multidisciplinary

Aluminum, a known neurotoxic substance, has been suggested as a contributing factor in the pathogenesis of Alzheimer's disease. Therapeutic efficacy of combined administration of citric acid (CA) and N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA) was evaluated in decreasing blood and brain aluminum concentration and parameters indicative of hematological disorders and brain oxidative stress. Adult male wistar rats were exposed to drinking water containing 0.2% aluminum nitrate for 8 months and treated once daily for 5 consecutive days with CA (50 mgykg, orally) or HEDTA (50 mgykg, intraperitoneally) either individually or in combination. Aluminum exposure significantly inhibited blood d-aminolevulinic acid dehydratase while increased zinc protoporphyrin confirming changed heme biosynthesis. Significant decrease in the level of glutathione S-transferase in various brain regions and an increase in whole brain thiobarbituric acid reactive substance, and oxidized glutathione (GSSG) levels were also observed. Glutathione peroxidase activity showed a significant increase in cerebellum of aluminum exposed rats. Most of the above parameters responded moderately to the individual treatment with CA and HEDTA, but significantly reduced blood and brain aluminum burden. However, more pronounced beneficial effects on some of the above described parameters were observed when CA and HEDTA were administered concomitantly. Blood and brain aluminum concentration however, showed no further decline on combined treatment over the individual effect with HEDTA or CA. We conclude that in order to achieve an optimum effect of chelation, combined administration of CA and HEDTA might be preferred. However, further work is needed before a final recommendation could be made. ᮊ

- by Ashish Mehta
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- Oxidative Stress, Biological Sciences, Aluminum, Environmental Sciences
- by Romolo Dorizzi
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- Biomedical Engineering, Inflammation, Osteoporosis, Zinc

In order to assess the condition of heavy metal pollution in the Yellow River, Lanzhou section, China, and to quantify heavy metal (copper, lead, zinc, and cadmium) contents in tissues (liver, kidney, gills, and muscles) of two fish species (Triplophysa pappenheimi and Gobio hwanghensis), levels of these four metals in the water body, sediment, and tissues of the two fish were measured using inductively coupled plasmaatomic emission spectrometry. The metal levels from this study were compared with the threshold values in the guidelines of water, sediment, and food given by the National Environmental Protection Agency of China, the National Oceanic and Atmospheric Administration of America, and the National Standards Management Department of China. We found the mean concentrations of Cu, Pb, Zn, and Cd in THE water body, sediment, and muscles of two fish species were far below the values in guidelines. We also found that the type of metals present and their concentrations varied in different tissues and species. The results suggested that (1) Cu, Pb, Zn, and Cd did not contaminate the aquatic ecosystem severely and did not threaten the safety of human consumption in the Yellow River, Lanzhou section, and (2) organs that are sensitive to accumulating heavy metals may be useful to develop bioindicators for monitoring metal contamination. Considering environmental variables, further study is necessary before deciding which fish species or tissue could be the ideal bioindicators for aquatic pollution.

- by Ji, Weihong
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- Analytical Chemistry, Turkey, China, Risk assessment

The metallothioneins (MT) are small, cysteine-rich heavy metal-binding proteins which participate in an array of protective stress responses. Although a single essential function of MT has not been demonstrated, MT of higher eukaryotes evolved as a mechanism to regulate zinc levels and distribution within cells and organisms. These proteins can also protect against some toxic metals and oxidative stress-inducing agents. In mice, among the four known MT genes, the MT-I and -II genes are most widely expressed. Transcription of these genes is rapidly and dramatically up-regulated in response to zinc and cadmium, as well as in response to agents which cause oxidative stress and/or inflammation. The six zinc-finger metal-responsive transcription factor MTF-1 plays a central role in transcriptional activation of the MT-I gene in response to metals and oxidative stress. Mutation of the MTF-1 gene abolishes these responses, and MTF-1 is induced to bind to the metal response elements in proximal MT promoter in cells treated with zinc or during oxidative stress. The exact molecular mechanisms of action of MTF-1 are not fully understood. Our studies suggest that the DNA-binding activity of MTF-1 in vivo and in vitro is reversibly activated by zinc interactions with the zinc-finger domain. This reflects heterogeneity in the structure and function of the six zinc fingers. We hypothesize that MTF-1 functions as a sensor of free zinc pools in the cell. Changes in free zinc may occur in response to chemically diverse inducers. MTF-1 also exerts effects on MT-I gene transcription which are independent of a large increase in MTF-1 DNA-binding activity. For example, cadmium, which has little effect on the DNA-binding activity of MTF-1 in vivo or in vitro, is a more potent inducer of MT gene expression than is zinc. The basic helix-loop-helix-leucine zipper protein, USF (upstream stimulatory factor family), also plays a role in regulating transcription of the mouse MT-I gene in response to cadmium or H 2 O 2 . Expression of dominant negative USF-1 or deletion of its binding site from the proximal promoter attenuates induction of the mouse MT-I gene. USF apparently functions in this context by interacting with as yet unidentified proteins which bind to an antioxidant response element which overlaps the USF-binding site (USF/ARE). Interestingly, this composite element does not participate in the induction of MT-I gene transcription by zinc or redox-cycling quinones. Thus, regulation of the mouse MT-I gene by metals and oxidative stress involves multiple signaling pathways which depend on the species of metal ion and the nature of the oxidative stress. BIOCHEM PHARMACOL 59;1:95-104, 2000.

Cadmium sulfide thin films were prepared by chemical bath on glass substrates at 80°C. CdS was Er-doped during the growth process by adding water-diluted Er͑NO 3 ͒ 3 3·H 2 O to the CdS aqueous growing solution. The relative volume of the doping solution was varied in order to obtain different doping levels. The crystalline structure of CdS:Er films was cubic zinc blende for all the doped layers prepared. The ͑111͒ interplanar distance has an irregular variation with the Er doping level. Consequently, the band gap energy ͑E g ͒ firstly increases and afterward diminishes becoming, at last, approximately constant at around E g = 2.37 eV. For higher doping levels, in the as-grown films, dark electrical conductivity ͑͒ values reach 1.8ϫ 10 −2 ⍀ −1 cm −1 at room temperature. The logarithm of vs 1 / kT plot, where k is Boltzmann's constant and T the absolute temperature, indicates an effective doping of CdS as a result of the Er introduction into the lattice of the material. Hall effect measurements reveal a n-type doping with 2.8ϫ 10 19 cm −3 as maximum carrier density.

- by Oscar Moreno
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- Engineering, Applied Physics, Crystal structure, Mathematical Sciences

We have employed differential scanning calorimetry (DSC) to investigate the thermally induced unfolding of native Cu,Zn-superoxide dismutase (SOD), the apoprotein derived from native SOD, and the zinc-substituted derivatives of the apoprotein. W e observe two overlapping melting transitions for native bovine SOD with heat capacity maxima at temperatures (T,) of 89 and 96 O C when a scanning rate of 0.82 deg/min is employed. By contrast, the dithionite-reduced native SOD (which contains Cu+ rather than Cu2+) exhibits only a single transition at 96 O C . Significantly, we find that the concentration of O2 present in native S O D samples influences the relative magnitudes of the 89 and 96 OC peaks. Specifically, the lower temperature transition becomes less pronounced as the concentration of O2 in the sample decreases.

- by Luis A Marky and +1
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- Biochemistry, Differential scanning calorimetry, Copper, Zinc

Objective: Biodegradable polycaprolactone/starch composites can be used for bone tissue engineering applications. The effect of the ratio of components on composite properties is of tremendous importance. Methods: Polycaprolactone/starch composite of 80/20 and 70/30 ratios were fabricated by dissolving them in chloroform followed by evaporation of the solvent. Results: The composites were characterized by fourier transform infrared spectroscopy. Their bioactivity was evaluated by studying the apatite formation ability after immersing the specimens in simulated body fluid. The results of compressive test on samples showed that the composite's modulus and strength approximated that of human trabecular bone. Mass loss in distilled water and starch degradation rate in PBS was evaluated, which showed that the starch ratio was effective in composite degradation. MTT analysis and alkaline phosphatase levels showed that this composite had no toxicity and could increase G-299 cell line osteoblastic activities. Conclusion: The increase in cellular osteoblastic activities and the ability for apatite formation on the composite surface, in addition to the polycaprolactone/starch samples' mechanical properties shows their capability to be used as substitutes for bone. Because this composite degradation rate is controlled by changing the starch ratio, it has the potential for use in bone tissue engineering applications. Samples that have a 70/30 ratio are considered optimal due to their enhanced cellular response and better mechanical properties.

- by Mehran Solati-Hashjin
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- Engineering, Materials Engineering, Chemical Engineering, Thermodynamics

Abstract: Regional modeling of subsurface cadmium and zinc transport in a diffusely polluted area in the south of the Netherlands is the subject of this study. The atmospheric deposition of cadmium and zinc was caused by three zinc-ore... more

The spinel ferrite system Ni 1−x Zn x La y Fe 2−y O 4 ; 0.0 ≤ x ≤ 1.0 and y = 0.0, 0.05 is prepared by standard ceramic method. X-ray diffraction is used to obtain the structural characterization of Ni, Zn, Ni-Zn and Ni-Zn-La ferrite. The influence of zinc ion substitution on the electrical properties of samples is investigated indicating, that the ac conductivity (ln σ) as well as dielectric constant (ε) are nearly constant for small Zn ion concentration, while they increase at high Zn content (x = 0.6). The calculated values of the activation energy confirm the obtained results and indicate the semiconductor properties of the investigated samples. The dielectric constant data shows more than one peak which is discussed in view of the ionization potential of each element and hopping mechanism.

- by ebtesam el farhatey
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- Materials Engineering, Materials Science, Materials Chemistry, X Rays

OBJECTIVE To assess the effect of smoking on sperm vitality, sperm DNA integrity, semen reactive oxygen species, and zinc levels in fertile men. METHODS One-hundred sixty men were investigated. They were divided into 2 equal groups: healthy fertile nonsmokers and healthy fertile smokers. They were subjected to history taking, clinical examination, and semen analysis. In their semen, sperm hypo-osmotic swelling test, sperm DNA fragmentation test, seminal reactive oxygen species, and zinc were assessed. RESULTS Compared with fertile nonsmokers, fertile smokers were significantly associated with lower hypo-osmotic swelling test and seminal zinc levels and significantly associated with higher sperm DNA fragmentation percent and seminal reactive oxygen species levels. CONCLUSION Smoking (cigarettes/day and duration) has detrimental effects on sperm motility, viability, DNA fragmentation, seminal zinc levels, and semen reactive oxygen species levels, even in fertile men, and it is directly correlated with cigarette quantity and smoking duration. UROLOGY 80: 822-825, 2012.

- by Taymour Mostafa
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- Urology, Medicine, Smoking, Reactive Oxygen Species

Bisthiourea Zinc Acetate (BTZA) a semi organic material has been synthesized by slow evaporation method using water as a solvent. The solubility studies have been carried out in aqueous solution in the temperature range 25 ˚C – 45 ˚C. Crystals have been grown from low temperature solution method by slow evaporation of saturated aqueous solution at room temperature. Single Crystal X-ray diffraction study has been carried out to determine the lattice parameter of the grown crystal. The spectral bands have been compared with similar thiourea complexes using FTIR spectrum in the range 400 – 4000 cm-1. Optical transmittance and absorption percentage of the grown crystal have been measured from UV-Vis studies. The thermal behavior has been investigated by thermogravimetric (TGA) and Differential Thermogram analyses (DTA). The mechanical strength and work hardening coefficient of the grown crystal have been analyzed by Vicker’s microhardness method. Keywords: Growth from solutions; X-ray d...

- by Ruby Nirmala
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- Computer Science, Chemistry, Nonlinear Optics, Zinc

Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

- by Pushparajah Thavarajah
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- Chemistry, Food Chemistry, Multidisciplinary, Concentration

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- by FERHAN CECEN
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- Kinetics, Activated Sludge, Environmental Pollution, Multidisciplinary

A total of 320 finishing pigs (PIC 327 × 1050; initially 98 kg) were used to determine the effects of adding Zn to diets containing ractopamine HCl (RAC) on muscle fiber type distribution, fresh chop color, and cooked meat characteristics. Dietary treatments were fed for approximately 35 d and consisted of a corn-soybean meal-based negative control (CON), a positive control diet with 10 mg/kg of RAC (RAC+), and the RAC+ diet plus 75, 150, or 225 mg/kg added Zn from either ZnO or Availa-Zn. Loins randomly selected from each treatment (n = 20) were evaluated using contrasts: CON vs. RAC+, interaction of Zn level × source, Zn level linear and quadratic polynomials, and Zn source. There were no Zn source effects or Zn source × level interactions throughout the study (P > 0.10). Pigs fed RAC+ had increased (P < 0.02) percentage type IIX and a tendency for increased (P = 0.10) percent type IIB muscle fibers. Increasing added Zn decreased (linear, P = 0.01) percentage type IIA and te...

- by Mathew Vaughn
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- Animal Science, Diet, Biological Sciences, Animal Feed

Mine associated wastewater is characteristically elevated in metals and other contaminants and has been conventionally treated with costly chemical applications. The development of passive treatment systems such as wetlands, which employ both biotic and abiotic processes, has been recognized as an economically feasible, ecologically acceptable treatment technology in the last decade. Not only can constructed wetlands provide an efficient facility

- by Aisling Osullivan
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- Passive Treatment, Mine Water, Ecological Niche Modeling, Food web
- by Marvin Salin
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- Kinetics, Escherichia coli, Zinc, Iron

Nitric oxide (NO) and reactive oxygen species (ROS) are emerging as important regulators of angiogenesis. NO enhances VEGF synthesis in several cell types and is required for execution of VEGF angiogenic effect in endothelial cells. Similarly, hydrogen peroxide induces VEGF synthesis and recent studies indicate the involvement of ROS in signaling downstream of VEGF stimulation. VEGF synthesis can not only be enhanced by gene transfer of VEGF but also by overexpression of NO synthase genes. Here, we examined the possibility of augmentation of VEGF production by gene transfer of copper/zinc superoxide dismutase (CuZnSOD, SOD1). Overexpression of human SOD1 in mouse NIH 3T3 fibroblasts increased SOD activity, enhanced intracellular generation of H 2 O 2 and significantly stimulated VEGF production as determined by increase in VEGF promoter activity, VEGF mRNA expression and VEGF protein synthesis. The stimulatory effect on VEGF synthesis induced by SOD1 gene transfer was reverted by overexpression of human catalase. The effect of H 2 O 2 produced by engineered cells is mediated by activation of hypoxia-inducible factor response element (HRE) as well as Sp1 recognition site of VEGF promoter. This data suggest the feasibility of stimulation of angiogenesis by overexpression of SOD1. (Mol Cell Biochem 264: [169][170][171][172][173][174][175][176][177][178][179][180][181] 2004)

In order to evaluate the metal contamination from kaolin industry discharges into rivers in the State of Minas Gerais, Brazil, samples of river water and fluvial sediment were collected up- and down-river from the industries and analysed todetect metal inputs. The metal examined included zinc, iron, andaluminium among others, being selected due to their toxicity andoccurence in waste waters. Metal inputs in the samples analysed appeared to be related to effluent discharges into the rivers. The river water showed high concentrations (in μg mL-1) of Zn (355), Fe (354) and Al (303). Sediment investigations indicated heavy enrichment (SEF = 9.4) for Zn. The Geoaccumulation Index for this element accounted for 3 (moderately to heavy polluted). River water pH of the sample collected near the effluent discharge site reached 3.7, suggesting inadequate treatment.

- by Joana Pereira
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- Multidisciplinary, River water, Minas Gerais, Zinc

Intrahippocampal injections of zinc chloride (5-10 nmol) caused a discrete lesion in the rat hippocampus, involving all neuronal perikarya. In addition to the necrosis, the lesion was also characterized by a decrease in staining of the neuropil, the presence of pyknotic neurons, and occasionally infarction. Pathological changes occurred within 8 h of an injection, and neuronal loss, as judged by the loss of Nissl staining, was complete within 24 h. On the other hand, the loss of acidophilic staining of the neurons was more gradual, as acid fuchsin staining was still present in neurons in the periphery of the damaged area 4 days later. In comparison with an excitotoxic lesion, glial infiltration into the damaged area was minimal, even up to 3 weeks later, suggesting that some glial cell toxicity also occurred.

- by Anders Lehmann
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- Psychology, Cognitive Science, Histology, Hippocampus

Background: Zinc deficiency is prevalent in children in developing countries. Supplemental zinc provides therapeutic benefits in diarrhea. Objective: We sought to measure the effect of supplemental zinc given with oral rehydration therapy during recovery from acute or persistent diarrhea. Design: We conducted pooled analyses including all available published and unpublished randomized controlled trials of the effects of supplementary oral zinc in children aged < 5 y with acute or persistent diarrhea. We used Cox survival regression analysis to evaluate the overall effect of zinc on continuation of diarrhea and possible differential effects in subgroups divided by sex, age, weight-for-height, and initial plasma zinc concentration. Dichotomous outcomes were analyzed by logistic regression. To assess the effects of excluding studies without original data from the pooled analyses, effect-size was estimated for all studies by using random-effects models. Results: Zinc-supplemented children had a 15% lower probability of continuing diarrhea on a given day (95% CI: 5%, 24%) in the acute-diarrhea trials and a 24% lower probability of continuing diarrhea (95% CI: 9%, 37%) and a 42% lower rate of treatment failure or death (95% CI: 10%, 63%) in the persistentdiarrhea trials. In none of the subgroup analyses were the 2 subgroups of each pair significantly different from each other; however, in persistent diarrhea there tended to be a greater effect in subjects aged < 12 mo, who were male, or who had wasting or lower baseline plasma zinc concentrations. Conclusion: Zinc supplementation reduces the duration and severity of acute and persistent diarrhea.

- by Adi Hidayat
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- Engineering, Developing Countries, Diarrhea, Developing Country

Abstract: As a group, heavy metals include both those essential for normal biological functioning (e.g., Cu and Zn), and nonessential metals (e.g., Cd, Hg, and Pb). Both essential and nonessential metals can be present at concentrations that disturb normal biological functions, and which evoke cellular stress responses. The cellular targets for metal toxicity include tissues of the kidney, liver, heart, and the immune response and nervous systems. Intriguingly, manipulations of specific metals, their reservoirs, and the cellular stress response can have therapeutic effects on certain diseases. In this minireview, we will consider both the biological responses to stressful levels of heavy metal cations, and experimental and clinical manipulations of these cations as a means to improve human health parameters.

- by Lawrence Hightower
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- Immune response, Vascular Surgery, Multidisciplinary, Heavy metals

The effects of cadmium and of combined treatments of cadmium, copper and zinc on growth, tolerance indices, mineral composition (N, P, K, Fe, Zn and Mn) and metal uptake of reed (Phragmites australis [(Cav.) Trin. ex Steudel]) were investigated in hydroponic experiments, with Cd concentrations ranging from 4.4 to 17.6 mM, either alone or combined with different treatments of Cu and Zn. Neither root nor shoot growth were affected by the treatments with 4.4 and 8.8 mM Cd alone. However, root and shoot length were significantly reduced by 17.6 mM Cd. Combined metal treatments significantly decreased shoot length, root number and plant fresh weight further than Cd alone, but not plant dry weight. Cd alone had no effect on tissue concentrations of N, P or K, while Mn concentration decreased in both shoot and root, and Zn concentration increased. As a result of the Cd, Cu and Zn (combined treatment) toxicity, the concentrations of N and K decreased in shoot and root tissues, respectively, and Mn concentration decreased in both shoot and root. Fe concentration increased in roots, leading to a significant relationship between root tissue Fe and Cd concentrations with increasing individual concentration of Cd (log 10 basis, P < 0.01) and in all the combined

- by Nadia Ali
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- Plant Biology, Aquatic botany, Wastewater Treatment, Copper

Silica gel was chemically modified with an N-acyl-N~-benzoylthiourea group. This material behaved as a selective means of preconcentrating Cu(II), Zn(II) and Cd(lI) from ethanol by the column technique. Ethanolic solutions having 6 gmol of the metal ions were percolated through the column and retentions of 100% were achieved for all metals. Zinc and copper were eluted quantitatively from the column bed with 5mL of ethanolic 0.1 molL -1 (for Zn) and 0.9 mol L -1 (for Cu) citric acid. Cadmium was recovered totally with 60 mL of ethanolic 2.0 tool L -1 citric acid. The modified silica was shown to be chemically stable after various adsorption-elution cycles (at least twenty).

- by Elvio Antonio Campos and +1
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- Analytical Chemistry, Transition-Metal Oxides, Copper, Silica

Tissue heavy metal concentrations are valuable in population and environmental monitoring.

- by Todd Schmitt and +1
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- Arsenic, Aging, Environmental Monitoring, Environmental Pollution

This paper presents the possibility of removing metal ions by applying the hybrid complexationultrafiltration process. The research was conducted on model solutions containing Zn(II) and Ni(II) ions. The complexing agent applied in the... more

- by Irena Korus
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- Chemical Engineering, Analytical Chemistry, Ultrafiltration, Metal Complexes

OBJECTIVE The role of leptin in the acute stress response to extracorporeal circulation has been well documented, however, the relationship between leptin and zinc has not been investigated previously. We aimed to research the circulating leptin, zinc, and copper levels before, during, and after the extracorporeal circulation, and effect of preoperative zinc administration to these. METHODS Twenty patients who were taken to elective coronary artery bypass grafting operations using extracorporeal circulation were taken to this research and divided into two equal groups (n1, n2). In both groups blood samples were taken just before the operation (T0), at the end of operation (T1), and at the first postoperative day (T2). In the second group (n2) oral zinc (50 mg, once a day) was administered to patients for 5 days, preoperatively. The serum leptin, zinc, and copper levels were studied. RESULTS In group n1 circulating leptin levels were significantly increased at T2 when compared to T0 ...

- by ISIK GORMUS
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- Inflammation, Medicine, Antioxidants, Copper

In this study, a simple method was developed to use water soluble polymer, polyacrylic acid, for the separation and pre-concentration of trace Cd, Cu and Zn prior to their analysis by flame atomic absorption spectrometry. For this purpose, the sample and poly-acrylic acid were mixed and the metal-bound polymer was precipitated by the addition of acetone. The precipitate was separated and dissolved in a minimum amount of water and aspirated into a flame AAS. The method was compared with traditional water insoluble sorbents in all aspects. The technique described is fast, simple, precise and inexpensive. Blank values were low and recoveries were 96.5% for Cd, 99.7% for Cu and Ž. y1 y1 y1 98.0% for Zn. Detection limits 3 were 1.8 g l for Cd, 2.5 g l for Cu, and 2.2 g l for Zn.

- by Suleyman Akman
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- Concentration, Copper, Physical sciences, Zinc

The main objective of the present study was to examine the dietary intake and physiological status of members of the US National Figure Skating Dance Team. Study participants included seven female and seven male figure skating dance pairs. Three-day food records were collected from each dancer and analyzed using a computerized nutrient database. Height, body weight and skinfold measurements were completed on each dancer. Body fat was estimated using the Jackson et al prediction equations. Fasting blood samples were collected for biochemical analysis. Total energy intake of female dancers (1416 kcal/d, 339 kjoules/day) was considerably lower than the dietary recommendations, while the male dancers appeared to have adequate energy intake (2837 kcal/d, 679 kjoules/day). Carbohydrate intake of both male and female dancers was below the recommendations, 44% and 51%, respectively, whereas total fat and protein intake of both male and female dancers were higher than the dietary recommendations. All dancers met at least 2/3 rd of the dietary recommendations for all micronutrients, except folate and zinc intake of the female dancers, which were 68% and 62% of the recommended values. Although, blood lipid concentrations and other physiological parameters of the overall group were within normal ranges, two of the dancers (14% of the dancers) had elevated blood cholesterol concentrations and low iron status. The results of the present study suggest that these elite figure skating dancers, especially females, may not be consuming adequate amounts of energyyielding nutrients and those that influence bone health. Future studies are needed to examine the effects of nutritional status on performance of these figure skating dancers and to develop strategies to improve the nutritional status of these elite dancers.

- by Satya Jonnalagadda
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- Nutrition and Dietetics, Nutrition, Dance, Sport

The corrosion inhibition of galvanized steel was studied in artificial acid rain solution using extracts of pigments normally used in organic coatings for corrosion control. It was established that a combination of zinc phosphate/molybdate and calcium ion exchange silica has a significant synergetic anticorrosion effect in the acid rain solution compared to the pigments used alone. Further, the charge transfer resistance of galvanized steel in acid rain solution saturated by the above pigment blend approaches that of strontium chromate in artificial acid rain solution. Use of the pigment blend was found to lead to development of a protective film, which is thought to be a complex mixture of calcium phosphates and zinc phosphate.

- by Ivan Zin
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- Materials Engineering, Mechanical Engineering, Civil Engineering, Corrosion Science

Using thermal analysis as well as isothermal gravimetric measurements, the thermal stability of the zinc nitrate(V) hexahydrate has been determined. Some intermediate products are the results of melting, evaporation, hydrolysis, polycondensation and decomposition processes occurring in the saltwater system up to 300°C. Solid phases were characterized by means of chemical analyses and X-ray powder diffraction method.

- by Krystyna Wieczorek-Ciurowa
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- Water, Decomposition, Zinc, Thermal Analysis

As-synthesized ZnS:Cu,Al nanocrystals with average size of 2-3 nm show abroad emission band peaking at 445 nm (blue) and a shoulder at around 540 nm (green). Annealing the nanocrystals in nitrogen gas results in a reduction in the intensity of the blue emission while enhancing the intensity of the green emission band. The maximum of the green emission is first redshifted to around 590 nm when the annealing temperature is increased to 400 • C, and later blueshifted to 564 and 500 nm for the samples annealed at 500 • C and 600 • C for 1 h, respectively. The lower phase-transition temperature (from zinc blende to wurtzite) and the donor-acceptor pair luminescence process in nanocrystals are discussed.

- by Nguyen Le Hung Nguyen
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- Nitrogen, Zinc, Phase transition

A complete set of platinum(II) solketal substituted phthalocyanines has been synthesized and characterized. To evaluate their potential as Type II photosensitizers for photodynamic therapy, comparative studies of their photophysical and photochemical properties with analogous zinc(II) series have been achieved: electronic absorption, fluorescence quantum yields, lifetimes, and fluorescence quenching by benzoquinone, as well as singlet oxygen generation and photodegradation. It appears that platinum(II) phthalocyanines are worth being used as Type II photosensitizers, as they exhibit good singlet oxygen generation and appropriate photodegradation.

- by yunus zorlu
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- Organic Chemistry, Fluorescence, Comparative Study, Photodynamic Therapy

Embedded resistor circuits have been generated with the use of a Micropen system, Ag conductor paste (DuPont 6142D), a new experimental resistor ink from DuPont (E84005-140), and Low Temperature Co-fired Ceramic (LTCC) green tape (DuPont A951). Sample circuits were processed under varying peak temperature ranges (835°C–875°C) and peak soak times (10 min–720 min). Resistors were characterized by SEM, TEM, EDS, and high-temperature XRD. Results indicate that devitrification of resistor glass phase to Celcian, Hexacelcian, and a Zinc-silicate phase occurred in the firing ranges used (835–875°C) but kinetics of divitrification vary substantially over this temperature range. The resistor material appears structurally and chemically compatible with the LTCC. RuO2 grains do not significantly react with the devitrifying matrix material during processing. RuO2 grains coarsen significantly with extended time and temperature and the electrical properties appear to be strongly affected by the change in RuO2 grain size.

- by Mark Rodriguez
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- Materials Engineering, Kinetics, Electroceramics, Zinc

A series of magnesium, aluminum, and zinc complexes of imidazol-2-ylidene-, imidazolin-2-ylidene-, and tetrahydropyrimidin-2-ylidene-derived N-heterocyclic carbenes (NHCs) was prepared. In addition, both symmetrical and unsymmetrical CO 2 -protected imidazol-2-ylidenes and imidazolin-2-ylidenes were prepared. Selected single-crystal Xray structures are reported. All compounds were investigated for their catalytic behavior in (poly)urethane (PUR) synthesis. Out of nine different compounds, the dimeric complex [Zn(CH 3 COO) 2 (1,3-dimesitylimidazol-2-ylidene)] 2 (7) proved to be the most active one, rivaling the industrially most relevant catalyst dibutyltin dilaurate in terms of catalytic ac-

- by Ulrich Decker
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- Inorganic Chemistry, Inorganic, Magnesium, Zinc