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Sample records for depleted zinc properties

  1. Depleted zinc: Properties, application, production.

    PubMed

    Borisevich, V D; Pavlov, A V; Okhotina, I A

    2009-01-01

    The addition of ZnO, depleted in the Zn-64 isotope, to the water of boiling water nuclear reactors lessens the accumulation of Co-60 on the reactor interior surfaces, reduces radioactive wastes and increases the reactor service-life because of the inhibitory action of zinc on inter-granular stress corrosion cracking. To the same effect depleted zinc in the form of acetate dihydrate is used in pressurized water reactors. Gas centrifuge isotope separation method is applied for production of depleted zinc on the industrial scale. More than 20 years of depleted zinc application history demonstrates its benefits for reduction of NPP personnel radiation exposure and combating construction materials corrosion.

  2. Genomic analysis, cytokine expression, and microRNA profiling reveal biomarkers of human dietary zinc depletion and homeostasis

    PubMed Central

    Ryu, Moon-Suhn; Langkamp-Henken, Bobbi; Chang, Shou-Mei; Shankar, Meena N.; Cousins, Robert J.

    2011-01-01

    Implementation of zinc interventions for subjects suspected of being zinc-deficient is a global need, but is limited due to the absence of reliable biomarkers. To discover molecular signatures of human zinc deficiency, a combination of transcriptome, cytokine, and microRNA analyses was applied to a dietary zinc depletion/repletion protocol with young male human subjects. Concomitant with a decrease in serum zinc concentration, changes in buccal and blood gene transcripts related to zinc homeostasis occurred with zinc depletion. Microarray analyses of whole blood RNA revealed zinc-responsive genes, particularly, those associated with cell cycle regulation and immunity. Responses of potential signature genes of dietary zinc depletion were further assessed by quantitative real-time PCR. The diagnostic properties of specific serum microRNAs for dietary zinc deficiency were identified by acute responses to zinc depletion, which were reversible by subsequent zinc repletion. Depression of immune-stimulated TNFα secretion by blood cells was observed after low zinc consumption and may serve as a functional biomarker. Our findings introduce numerous novel candidate biomarkers for dietary zinc status assessment using a variety of contemporary technologies and which identify changes that occur prior to or with greater sensitivity than the serum zinc concentration which represents the current zinc status assessment marker. In addition, the results of gene network analysis reveal potential clinical outcomes attributable to suboptimal zinc intake including immune function defects and predisposition to cancer. These demonstrate through a controlled depletion/repletion dietary protocol that the illusive zinc biomarker(s) can be identified and applied to assessment and intervention strategies. PMID:22171008

  3. Genomic analysis, cytokine expression, and microRNA profiling reveal biomarkers of human dietary zinc depletion and homeostasis.

    PubMed

    Ryu, Moon-Suhn; Langkamp-Henken, Bobbi; Chang, Shou-Mei; Shankar, Meena N; Cousins, Robert J

    2011-12-27

    Implementation of zinc interventions for subjects suspected of being zinc-deficient is a global need, but is limited due to the absence of reliable biomarkers. To discover molecular signatures of human zinc deficiency, a combination of transcriptome, cytokine, and microRNA analyses was applied to a dietary zinc depletion/repletion protocol with young male human subjects. Concomitant with a decrease in serum zinc concentration, changes in buccal and blood gene transcripts related to zinc homeostasis occurred with zinc depletion. Microarray analyses of whole blood RNA revealed zinc-responsive genes, particularly, those associated with cell cycle regulation and immunity. Responses of potential signature genes of dietary zinc depletion were further assessed by quantitative real-time PCR. The diagnostic properties of specific serum microRNAs for dietary zinc deficiency were identified by acute responses to zinc depletion, which were reversible by subsequent zinc repletion. Depression of immune-stimulated TNFα secretion by blood cells was observed after low zinc consumption and may serve as a functional biomarker. Our findings introduce numerous novel candidate biomarkers for dietary zinc status assessment using a variety of contemporary technologies and which identify changes that occur prior to or with greater sensitivity than the serum zinc concentration which represents the current zinc status assessment marker. In addition, the results of gene network analysis reveal potential clinical outcomes attributable to suboptimal zinc intake including immune function defects and predisposition to cancer. These demonstrate through a controlled depletion/repletion dietary protocol that the illusive zinc biomarker(s) can be identified and applied to assessment and intervention strategies.

  4. The protective role of zinc against acute toxicity of depleted uranium in rats.

    PubMed

    Hao, Yuhui; Ren, Jiong; Liu, Jing; Luo, Shenglin; Ma, Ting; Li, Rong; Su, Yongping

    2012-12-01

    Depleted uranium (DU) has been widely used in both civilian and military activities and contributes to health problems. This study was undertaken to evaluate the protective role of zinc against acute toxicity of DU. Sprague Dawley rats were injected with DU (10 mg/kg, i.p.) to create a toxicity model (DU group). Before and after the injection of DU, zinc sulphate (10 mg/kg, i.p.) was administered once a day for 2 days. The survival rates at 30 days post DU administration and the effects of zinc at 4 days post DU administration were evaluated. Our data indicate that zinc has obvious protective effects, especially pre-treatment with zinc. Rats pre-treated with zinc had significantly higher survival rates than rats in the DU group, with 60.03% more surviving. In addition, at 4 days post DU administration, the former had lower kidney uranium content, insignificant renal tubular epithelial cell necrosis and less transparent tubes. Meanwhile, blood urea nitrogen, creatinine and urine N-acethyl-β-d-glucosaminidase concentrations were significantly decreased; the gene expression levels of metallothionein (MT) in kidney tissues were significantly increased; and catalase levels were increased and malondialdehyde levels were decreased. In conclusion, pre-treatment with zinc significantly alleviated acute toxicity of DU, and the mechanism appeared to be related to the induction of MT synthesis and enhancement of the antioxidant function.

  5. Dietary zinc depletion and repletion affects plasma proteins: an analysis of the plasma proteome

    PubMed Central

    Wickwire, Kathie; Ho, Emily; Chung, Carolyn S.; King, Janet

    2014-01-01

    Zinc (Zn) deficiency is a problem worldwide. Current methods for assessing Zn status are limited to measuring plasma or serum Zn within populations suspected of deficiency. Despite the high prevalence of Zn deficiency in the human population there are no methods currently available for sensitively assessing Zn status among individuals. The purpose of this research was to utilize a proteomic approach using two-dimensional gel electrophoresis (2DE) and mass spectrometry to identify protein biomarkers that were sensitive to changes in dietary Zn levels in humans. Proteomic analysis was performed in human plasma samples (n = 6) obtained from healthy adult male subjects that completed a dietary Zn depletion/repletion protocol, current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men. Chung et al. (Am J Clin Nutr 87 (5):1224–1229, 2008). After a 13 day Zn acclimatization period where subjects consumed a Zn-adequate diet, the male subjects consumed a marginal Zn-depleted diet for 42 days followed by consumption of a Zn-repleted diet for 28 days. The samples at baseline, end of depletion and end of repletion were pre-fractionated through immuno-affinity columns to remove 14 highly abundant proteins, and each fraction separated by 2DE. Following staining by colloidal Coomassie blue and densitometric analysis, three proteins were identified by mass spectrometry as affected by changes in dietary Zn. Fibrin β and chain E, fragment double D were observed in the plasma protein fraction that remained bound to the immuno-affinity column. An unnamed protein that was related to immunoglobulins was observed in the immunode-pleted plasma fraction. Fibrin β increased two-fold following the Zn depletion period and decreased to baseline values following the Zn repletion period; this protein may serve as a viable biomarker for Zn status in the future. PMID:23255060

  6. Dietary zinc depletion and repletion affects plasma proteins: an analysis of the plasma proteome.

    PubMed

    Grider, Arthur; Wickwire, Kathie; Ho, Emily; Chung, Carolyn S; King, Janet

    2013-02-01

    Zinc (Zn) deficiency is a problem world-wide. Current methods for assessing Zn status are limited to measuring plasma or serum Zn within populations suspected of deficiency. Despite the high prevalence of Zn deficiency in the human population there are no methods currently available for sensitively assessing Zn status among individuals. The purpose of this research was to utilize a proteomic approach using two-dimensional gel electrophoresis (2DE) and mass spectrometry to identify protein biomarkers that were sensitive to changes in dietary Zn levels in humans. Proteomic analysis was performed in human plasma samples (n = 6) obtained from healthy adult male subjects that completed a dietary Zn depletion/repletion protocol, current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men. Chung et al. (Am J Clin Nutr 87 (5):1224-1229, 2008). After a 13 day Zn acclimatization period where subjects consumed a Zn-adequate diet, the male subjects consumed a marginal Zn-depleted diet for 42 days followed by consumption of a Zn-repleted diet for 28 days. The samples at baseline, end of depletion and end of repletion were pre-fractionated through immuno-affinity columns to remove 14 highly abundant proteins, and each fraction separated by 2DE. Following staining by colloidal Coomassie blue and densitometric analysis, three proteins were identified by mass spectrometry as affected by changes in dietary Zn. Fibrin β and chain E, fragment double D were observed in the plasma protein fraction that remained bound to the immunoaffinity column. An unnamed protein that was related to immunoglobulins was observed in the immunodepleted plasma fraction. Fibrin β increased two-fold following the Zn depletion period and decreased to baseline values following the Zn repletion period; this protein may serve as a viable biomarker for Zn status in the future.

  7. Dietary zinc depletion and repletion affects plasma proteins: an analysis of the plasma proteome.

    PubMed

    Grider, Arthur; Wickwire, Kathie; Ho, Emily; Chung, Carolyn S; King, Janet

    2013-02-01

    Zinc (Zn) deficiency is a problem world-wide. Current methods for assessing Zn status are limited to measuring plasma or serum Zn within populations suspected of deficiency. Despite the high prevalence of Zn deficiency in the human population there are no methods currently available for sensitively assessing Zn status among individuals. The purpose of this research was to utilize a proteomic approach using two-dimensional gel electrophoresis (2DE) and mass spectrometry to identify protein biomarkers that were sensitive to changes in dietary Zn levels in humans. Proteomic analysis was performed in human plasma samples (n = 6) obtained from healthy adult male subjects that completed a dietary Zn depletion/repletion protocol, current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men. Chung et al. (Am J Clin Nutr 87 (5):1224-1229, 2008). After a 13 day Zn acclimatization period where subjects consumed a Zn-adequate diet, the male subjects consumed a marginal Zn-depleted diet for 42 days followed by consumption of a Zn-repleted diet for 28 days. The samples at baseline, end of depletion and end of repletion were pre-fractionated through immuno-affinity columns to remove 14 highly abundant proteins, and each fraction separated by 2DE. Following staining by colloidal Coomassie blue and densitometric analysis, three proteins were identified by mass spectrometry as affected by changes in dietary Zn. Fibrin β and chain E, fragment double D were observed in the plasma protein fraction that remained bound to the immunoaffinity column. An unnamed protein that was related to immunoglobulins was observed in the immunodepleted plasma fraction. Fibrin β increased two-fold following the Zn depletion period and decreased to baseline values following the Zn repletion period; this protein may serve as a viable biomarker for Zn status in the future. PMID:23255060

  8. Fluorescence depletion properties of insulin–gold nanoclusters

    PubMed Central

    Chen, Po-Fu; Liu, Chien-Liang; Lin, Wei-Kuan; Chen, Kuan-Chieh; Chou, Pi-Tai; Chu, Shi-Wei

    2015-01-01

    Insulin–gold nanoclusters exhibit outstanding biocompatibility, photostability, and fluorescence quantum efficiency. However, they have never been used in superresolution microscopy, which requires nonlinear switching or saturation of fluorescence. Here we examine the fluorescence and stimulated emission depletion properties of gold nanoclusters. Their bleaching rate is very slow, demonstrating superior photostability. Surprisingly, however, the best depletion efficiency is less than 70%, whereas the depletion intensity requirement is much higher than the expectation from a simple two-level model. Fluorescence lifetime measurement revealed two distinct lifetime components, which indicate intersystem and reverse intersystem crossing during excitation. Based on population dynamic calculation, excellent agreement of the maximal depletion efficiency is found. Our work not only features the first examination of STED with metallic clusters, but also reveals the significance of molecular transition dynamics when considering a STED labeling. PMID:26309767

  9. Accumulation of manganese superoxide dismutase under metal-depleted conditions: proposed role for zinc ions in cellular redox balance.

    PubMed Central

    Otsu, Kaoru; Ikeda, Yoshitaka; Fujii, Junichi

    2004-01-01

    A diet low in copper results in increased levels of MnSOD (manganese superoxide dismutase), a critical antioxidative enzyme conferring protection against oxidative stress, in rat liver mitochondria. The mechanism for this was investigated using cultured HepG2 cells, a human hepatocellular carcinoma-derived line. MnSOD activity increased 5-7-fold during incubation in a medium supplemented with metal-depleted fetal bovine serum, with a corresponding elevation of its mRNA levels. Metal depletion also decreased CuZnSOD and glutathione peroxidase levels to approx. 70-80% of baseline. When zinc ions were added to the medium at micromolar levels, MnSOD accumulation was suppressed; however, copper ions had essentially no effect on MnSOD expression. Since the intracellular redox status was shifted to a more oxidized state by metal depletion, we examined the DNA-binding activity of NF-kappaB (nuclear factor-kappaB), an oxidative stress-sensitive transactivating factor that plays a primary role in MnSOD induction. A gel shift assay indicated that the DNA-binding activity of NF-kappaB was increased in cells maintained in metal-depleted culture, suggesting the involvement of the transactivating function of NF-kappaB in this induction. This was further supported by the observation that curcumin suppressed both the DNA-binding activity of NF-kappaB and the induction of MnSOD mRNA in cells cultivated under metal-depleted conditions. These results suggest that the level of zinc, rather than copper, is a critical regulatory factor in MnSOD expression. It is possible that a deficiency of zinc in the low-copper diet may be primarily involved in MnSOD induction. PMID:14531733

  10. Antifouling properties of zinc oxide nanorod coatings.

    PubMed

    Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

    2014-01-01

    In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions.

  11. Antifouling properties of zinc oxide nanorod coatings.

    PubMed

    Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

    2014-01-01

    In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions. PMID:25115521

  12. Effects of zinc depletion and repletion during lactation on rat dams and their offspring

    SciTech Connect

    Dibi, K.

    1985-01-01

    The effects of feeding 5 mg Zn/kg, 12 mg Zn/kg, 50 mg Zn/kg in egg white diets and 50 mg Zn/kg in defatted glandless cottonseed diet on postnatal growth and tissue zinc concentrations of dams and neonates were investigated. One or more of the following tissues were obtained on days 7, 14, 21, and 56 for analyses: femur, liver, brain, testes, spleen, and/or blood. Dams fed the cottonseed diet weighted more than dams fed the egg white diets. Dams fed zinc in cottonseed diet had higher blood zinc concentrations than dams fed zinc in the egg white diets. Dams and the offspring fed 50 mg zn/kg egg white diet had higher femur zinc levels than dams and the offspring fed 50 mg Zn/kg in the cottonseed diet. There was no difference in the weight gain/loss of dams fed 50 mg Zn/kg or 12 mg Zn/kg egg white diets. Femur zinc concentrations of pups suckling dams fed 50 mg Zn/kg egg white were higher than femur zinc concentrations of pups suckling dams fed 12 mg Zn/kg egg white diet. Body weights and tissue zinc concentrations of the neonates suckling dams fed 5 mg Zn/kg egg white diet and then repleted with zinc in either egg white or cottonseed diet were similar. There was complete recovery when rats were fed 5 mg Zn/kg and then repleted with zinc at 50 mg Zn/kg level. Therefore, the protein source did not have statistically significantly different effects on zinc availability to the rats.

  13. Thermodynamic properties of lanthanum in gallium-zinc alloys

    NASA Astrophysics Data System (ADS)

    Dedyukhin, A. S.; Shepin, I. E.; Kharina, E. A.; Shchetinskiy, A. V.; Volkovich, V. A.; Yamshchikov, L. F.

    2016-09-01

    Thermodynamic properties of lanthanum were determined in gallium-zinc alloys of the eutectic and over-eutectic compositions. The electromotive force measurements were used to determine thermodynamic activity and sedimentation technique to measure solubility of lanthanum in liquid metal alloys. Temperature dependencies of lanthanum activity, solubility and activity coefficients in alloys with Ga-Zn mixtures containing 3.64, 15 and 50 wt. % zinc were obtained.

  14. Restoring wtp53 activity in HIPK2 depleted MCF7 cells by modulating metallothionein and zinc.

    PubMed

    Puca, Rosa; Nardinocchi, Lavinia; Bossi, Gianluca; Sacchi, Ada; Rechavi, Gideon; Givol, David; D'Orazi, Gabriella

    2009-01-01

    The maintenance of p53 transactivation activity is important for p53 apoptotic function. We have shown that stable knockdown of HIPK2 induces p53 misfolding with inhibition of p53 target gene transcription. In this study we established a lentiviral-based system for doxycyclin (Dox)-induced conditional interference of HIPK2 expression to evaluate the molecular mechanisms involved in p53 deregulation. We found that HIPK2 knockdown induced metallothionein 2A (MT2A) upregulation as assessed by RT-PCR analysis, increased promoter acetylation, and increased promoter luciferase activity. The MT2A upregulation correlated with resistance to Adriamycin (ADR)-driven apoptosis and with p53 inhibition. Thus, acute knockdown of HIPK2 (HIPK2i) induced misfolded p53 protein in MCF7 breast cancer cells and inhibited p53 DNA-binding and transcription activities in response to ADR treatment. Previous works show that MT may modulate p53 activity through zinc exchange. Here, we found that inhibition of MT2A expression by siRNA in the HIPK2i cells restored p53 transcription activity. Similarly zinc supplementation to HIPK2i cells restored p53 transcription activity and drug-induced apoptosis. These data support the notion that MT2A is involved in p53 deregulation and strengthen the possibility that combination of chemotherapy and zinc might be useful to treat tumors with inactive wtp53. PMID:18996371

  15. Zinc

    MedlinePlus

    ... ulcers and promoting weight gain in people with eating disorders such as anorexia nervosa. Some people use zinc ... is abnormal): 25-100 mg zinc. For the eating disorder anorexia nervosa: 100 mg of zinc gluconate daily. ...

  16. Candida albicans Induces Metabolic Reprogramming in Human NK Cells and Responds to Perforin with a Zinc Depletion Response

    PubMed Central

    Hellwig, Daniela; Voigt, Jessica; Bouzani, Maria; Löffler, Jürgen; Albrecht-Eckardt, Daniela; Weber, Michael; Brunke, Sascha; Martin, Ronny; Kurzai, Oliver; Hünniger, Kerstin

    2016-01-01

    As part of the innate immune system, natural killer (NK) cells are directly involved in the response to fungal infections. Perforin has been identified as the major effector molecule acting against many fungal pathogens. While several studies have shown that perforin mediated fungicidal effects can contribute to fungal clearance, neither the activation of NK cells by fungal pathogens nor the effects of perforin on fungal cells are well-understood. In a dual approach, we have studied the global gene expression pattern of primary and cytokine activated NK cells after co-incubation with Candida albicans and the transcriptomic adaptation of C. albicans to perforin exposure. NK cells responded to the fungal pathogen with an up-regulation of genes involved in immune signaling and release of cytokines. Furthermore, we observed a pronounced increase of genes involved in glycolysis and glycolysis inhibitor 2-deoxy-D-glucose impaired C. albicans induced NK cell activation. This strongly indicates that metabolic adaptation is a major part of the NK cell response to C. albicans infections. In the fungal pathogen, perforin induced a strong up-regulation of several fungal genes involved in the zinc depletion response, such as PRA1 and ZRT1. These data suggest that fungal zinc homeostasis is linked to the reaction to perforin secreted by NK cells. However, deletion mutants in PRA1 and ZRT1 did not show altered susceptibility to perforin. PMID:27242763

  17. Magnetic properties of bio-synthesized zinc ferrite nanoparticles

    SciTech Connect

    Yeary, Lucas W; Moon, Ji Won; Rawn, Claudia J; Love, Lonnie J; Rondinone, Adam Justin; Thompson, James R; Chakoumakos, Bryan C; Phelps, Tommy Joe

    2011-01-01

    The magnetic properties of zinc ferrite (Zn-substituted magnetite, Zn{sub y}Fe{sub 1-y}Fe{sub 2}O{sub 4}) formed by a microbial process compared favorably with chemically synthesized materials. A metal reducing bacterium, Thermoanaerobacter, strain TOR-39 was incubated with Zn{sub x}Fe{sub 1-x}OOH (x=0.01, 0.1, and 0.15) precursors and produced nanoparticulate zinc ferrites. Composition and crystalline structure of the resulting zinc ferrites were verified using X-ray fluorescence, X-ray diffraction, transmission electron microscopy, and neutron diffraction. The average composition from triplicates gave a value for y of 0.02, 0.23, and 0.30 with the greatest standard deviation of 0.02. Average crystallite sizes were determined to be 67, 49, and 25 nm, respectively. While crystallite size decreased with more Zn substitution, the lattice parameter and the unit cell volume showed a gradual increase in agreement with previous literature values. The magnetic properties were characterized using a superconducting quantum interference device magnetometer and were compared with values for the saturation magnetization (M{sub s}) reported in the literature. The averaged M{sub s} values for the triplicates with the largest amount of zinc (y=0.30) gave values of 100.1, 96.5, and 69.7 emu/g at temperatures of 5, 80, and 300 K, respectively indicating increased magnetic properties of the bacterially synthesized zinc ferrites.

  18. Antimicrobial property of zinc based nanoparticles

    NASA Astrophysics Data System (ADS)

    Chiriac, V.; Stratulat, D. N.; Calin, G.; Nichitus, S.; Burlui, V.; Stadoleanu, C.; Popa, M.; Popa, I. M.

    2016-06-01

    Pathogen bacteria strains with wide spectrum can cause serious infections with drastic damages on humans. There are studies reflecting antibacterial effect of nanoparticles type metal or metal oxides as an alternative or concurrent treatment to the diseases caused by infectious agents. Synthesised nanoparticles using different methods like sol-gel, hydrothermal or plant extraction were tested following well-established protocols with the regard to their antimicrobial activity. It was found that zinc based nanoparticles possess strong synergistic effect with commonly used antibiotics on infection tratment.

  19. Properties of Zip4 accumulation during zinc deficiency and its usefulness to evaluate zinc status: a study of the effects of zinc deficiency during lactation.

    PubMed

    Hashimoto, Ayako; Nakagawa, Miki; Tsujimura, Natsuki; Miyazaki, Shiho; Kizu, Kumiko; Goto, Tomoko; Komatsu, Yusuke; Matsunaga, Ayu; Shirakawa, Hitoshi; Narita, Hiroshi; Kambe, Taiho; Komai, Michio

    2016-03-01

    Systemic and cellular zinc homeostasis is elaborately controlled by ZIP and ZnT zinc transporters. Therefore, detailed characterization of their expression properties is of importance. Of these transporter proteins, Zip4 functions as the primarily important transporter to control systemic zinc homeostasis because of its indispensable function of zinc absorption in the small intestine. In this study, we closely investigated Zip4 protein accumulation in the rat small intestine in response to zinc status using an anti-Zip4 monoclonal antibody that we generated and contrasted this with the zinc-responsive activity of the membrane-bound alkaline phosphatase (ALP). We found that Zip4 accumulation is more rapid in response to zinc deficiency than previously thought. Accumulation increased in the jejunum as early as 1 day following a zinc-deficient diet. In the small intestine, Zip4 protein expression was higher in the jejunum than in the duodenum and was accompanied by reduction of ALP activity, suggesting that the jejunum can become zinc deficient more easily. Furthermore, by monitoring Zip4 accumulation levels and ALP activity in the duodenum and jejunum, we reasserted that zinc deficiency during lactation may transiently alter plasma glucose levels in the offspring in a sex-specific manner, without affecting homeostatic control of zinc metabolism. This confirms that zinc nutrition during lactation is extremely important for the health of the offspring. These results reveal that rapid Zip4 accumulation provides a significant conceptual advance in understanding the molecular basis of systemic zinc homeostatic control, and that properties of Zip4 protein accumulation are useful to evaluate zinc status closely. PMID:26702153

  20. Properties of Zip4 accumulation during zinc deficiency and its usefulness to evaluate zinc status: a study of the effects of zinc deficiency during lactation.

    PubMed

    Hashimoto, Ayako; Nakagawa, Miki; Tsujimura, Natsuki; Miyazaki, Shiho; Kizu, Kumiko; Goto, Tomoko; Komatsu, Yusuke; Matsunaga, Ayu; Shirakawa, Hitoshi; Narita, Hiroshi; Kambe, Taiho; Komai, Michio

    2016-03-01

    Systemic and cellular zinc homeostasis is elaborately controlled by ZIP and ZnT zinc transporters. Therefore, detailed characterization of their expression properties is of importance. Of these transporter proteins, Zip4 functions as the primarily important transporter to control systemic zinc homeostasis because of its indispensable function of zinc absorption in the small intestine. In this study, we closely investigated Zip4 protein accumulation in the rat small intestine in response to zinc status using an anti-Zip4 monoclonal antibody that we generated and contrasted this with the zinc-responsive activity of the membrane-bound alkaline phosphatase (ALP). We found that Zip4 accumulation is more rapid in response to zinc deficiency than previously thought. Accumulation increased in the jejunum as early as 1 day following a zinc-deficient diet. In the small intestine, Zip4 protein expression was higher in the jejunum than in the duodenum and was accompanied by reduction of ALP activity, suggesting that the jejunum can become zinc deficient more easily. Furthermore, by monitoring Zip4 accumulation levels and ALP activity in the duodenum and jejunum, we reasserted that zinc deficiency during lactation may transiently alter plasma glucose levels in the offspring in a sex-specific manner, without affecting homeostatic control of zinc metabolism. This confirms that zinc nutrition during lactation is extremely important for the health of the offspring. These results reveal that rapid Zip4 accumulation provides a significant conceptual advance in understanding the molecular basis of systemic zinc homeostatic control, and that properties of Zip4 protein accumulation are useful to evaluate zinc status closely.

  1. Trace elements in chondritic stratospheric particles - Zinc depletion as a possible indicator of atmospheric entry heating

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Sutton, S. R.

    1992-01-01

    Major-element abundances in 11 C, C?, and TCA cosmic dust particles have been measured using SEM and TEM energy dispersive X-ray (EDX) systems. The Fe/Ni ratio, when coupled with major element abundances, appears to be a useful discriminator of cosmic particles. Three particles classified as C?, but having Fe/Ni peak height ratios similar to those measured on the powdered Allende meteorite sample in their HSC EDX spectra, exhibit chondritic minor-/trace-element abundance patterns, suggesting they are extraterrestrial. The one particle classified as C-type, but without detectable Ni in its JSC EDX spectrum, exhibits an apparently nonchondritic minor-/trace-element abundance pattern. A class of particles that are chondritic except for large depletions in the volatile elements Zn and S has been identified. It is likely that these particles condensed with a C1 abundance pattern and that Zn and S were removed by some subsequent process.

  2. The Antimicrobial Properties of Zinc-Releasing Bioceramics

    NASA Astrophysics Data System (ADS)

    He, Xin

    Up to 80% of nosocomial infections are caused by biofilm-producing bacteria such as Staphylococci and Pseudomonas aeruginosa. These types of microorganisms can become resistant to antibiotics and are difficult to eliminate. As such, there is tremendous interest in developing bioactive implant materials that can help to minimize these post- operative infections. Using water-based chemistry, we developed an economical, biodegradable and biocompatible orthopedic implant material consisting of zinc- doped hydroxyapatite (HA), which mimics the main inorganic component of the bone. Because the crystallinity of HA is typically too compact for efficient drug release, we substituted calcium ions in HA with zinc during the synthesis step to perturb the crystal structure. An added benefit is that zinc itself is a microelement of the human body with anti-inflammatory property, and we hypothesized that Zn-doped HA is an inherently antibacterial material. All HA samples were synthesized by a co-precipitation method using aqueous solutions of Zinc nitrate, Calcium Nitrate, and Ammonium Phosphate. XRD data showed that Zn was successfully incorporated into the HA. The effectiveness of Zn-doped HA against a model biofilm-forming bacterium is currently being evaluated using a wild-type strain and a streptomycin- resistant strain of Pseudomonas syringae pv. papulans (Psp) which is a plant pathogen isolated from diseased apples. Key words: Hydroxyapatite, Zinc, Citrate, Pseudomonas, Antibacterial.

  3. Alterations in ethanol-induced accumbal transmission after acute and long-term zinc depletion.

    PubMed

    Morud, Julia; Adermark, Louise; Ericson, Mia; Söderpalm, Bo

    2015-01-01

    Alcoholism is subject to extensive research, but the role of changes in metabolism caused by alcohol consumption has been poorly investigated. Zinc (Zn(2+) ) deficiency is a common metabolic aberration among alcoholics and Zn(2+) influences the function of ligand-gated ion channels, known pharmacological targets of ethanol (EtOH). Here, we investigate whether manipulation of extracellular levels of Zn(2+) modulates EtOH-induced increases of dopamine (DA) output, as measured by in vivo microdialysis in the rat, and whether voluntary EtOH consumption is altered by Zn(2+) deficiency. Our findings show that the Zn(2+) -chelating agent tricine slowly raises DA levels when perfused in the nucleus accumbens (nAc), whereas the more potent Zn(2+) chelator TPEN reduces DA levels. We also show that pre-treatment with either tricine or TPEN blocks the EtOH-induced DA elevation. Chronic Zn(2+) deficiency induced by a Zn(2+) -free diet did not affect EtOH consumption, but excitatory transmission, assessed by striatal field-potential recordings in the nAc shell, was significantly modulated both by Zn(2+) -free diet and by EtOH consumption, as compared with the EtOH naïve controls. The present study indicates that Zn(2+) influences EtOH's interaction with the brain reward system, possibly by interfering with glycine receptor and GABAA receptor function. This also implies that Zn(2+) deficiency among alcoholics may be important to correct in order to normalize important aspects of brain function.

  4. Zinc.

    PubMed

    Barceloux, D G

    1999-01-01

    The use of zinc in metal alloys and medicinal lotions dates back before the time of Christ. Currently, most of the commercial production of zinc involves the galvanizing of iron and the manufacture of brass. Some studies support the use of zinc gluconate lozenges to treat the common cold, but there are insufficient data at this time to recommend the routine use of these lozenges. Zinc is an essential co-factor in a variety of cellular processes including DNA synthesis, behavioral responses, reproduction, bone formation, growth, and wound healing. Zinc is a relatively common metal with an average concentration of 50 mg/kg soil and a range of 10-300 mg/kg soil. Meat, seafood, dairy products, nuts, legumes, and whole grains contain relatively high concentrations of zinc. The mobility of zinc in anaerobic environments is poor and therefore severe zinc contamination occurs primarily near points sources of zinc release. The recommended daily allowance for adults is 15 mg zinc. The ingestion of 1-2 g zinc sulfate produces emesis. Zinc compounds can produce irritation and corrosion of the gastrointestinal tract, along with acute renal tubular necrosis and interstitial nephritis. Inhalation of high concentrations of zinc chloride from smoke bombs detonated in closed spaces may cause chemical pneumonitis and adult respiratory distress syndrome. In the occupational setting inhalation of fumes from zinc oxide is the most common cause of metal fume fever (fatigue, chills, fever, myalgias, cough, dyspnea, leukocytosis, thirst, metallic taste, salivation). Zinc compounds are not suspected carcinogens. Treatment of zinc toxicity is supportive. Calcium disodium ethylenediaminetetraacetate (CaNa2EDTA) is the chelator of choice based on case reports that demonstrate normalization of zinc concentrations, but there are few clinical data to confirm the efficacy of this agent. PMID:10382562

  5. Depleted uranium: properties, military use and health risks.

    PubMed

    Fairlie, Ian

    2009-01-01

    This article describes uranium and depleted uranium (DU), their similar isotopic compositions, how DU arises, its use in munitions and armour-proofing, and its pathways for human exposures. Particular attention is paid to the evidence of DU's health effects from cell and animal experiments and from epidemiology studies. It is concluded that a precautionary approach should be adopted to DU and that there should be a moratorium on its use by military forces. International efforts to this end are described.

  6. Investigation of Optical Properties of Zinc Oxide Photodetector

    NASA Astrophysics Data System (ADS)

    Chism, Tyler

    UV photodetection devices have many important applications for uses in biological detection, gas sensing, weaponry detection, fire detection, chemical analysis, and many others. Today's photodetectors often utilize semiconductors such as GaAs to achieve high responsivity and sensitivity. Zinc oxide, unlike many other semiconductors, is cheap, abundant, non-toxic, and easy to grow different morphologies at the micro and nano scale. With the proliferation of these devices also comes the impending need to further study optics and photonics in relation to phononics and plasmonics, and the general principles underlying the interaction of photons with solid state matter and, specifically, semiconductors. For this research a metal-semiconductor-metal UV photodetector has been fabricated by using a quartz substrate on top of which was deposited micropatterned gold in an interdigitated electrode design. On this, sparsely coated zinc oxide nano trees were hydrothermally grown. The UV photodetection device showed promise for detection applications, especially because zinc oxide is also very thermally stable, a quality which is highly sought after in today's UV photodetectors. Furthermore, the newly synthesized photodetector was used to investigate optical properties and how they respond to different stimuli. It was discovered that the photons transmitted through the sparsely coated zinc oxide nano trees decreased as the voltage across the device increased. This research is aimed at better understanding photons interaction with matter and also to open the door for new devices with tunable optical properties such as transmission.

  7. Optical and field emission properties of Zinc Oxide nanostructures.

    PubMed

    Pan, Hui; Zhu, Yanwu; Ni, Zhenhua; Sun, Han; Poh, Cheekok; Lim, Sanhua; Sow, Chornghaur; Shen, Zexiang; Feng, Yuanping; Lin, Jianyi

    2005-10-01

    Zinc Oxide (ZnO) nano-pikes were produced by oxidative evaporation and condensation of Zn powders. The crystalline structure and optical properties of the ZnO nanostructures (ZnONs) greatly depend on the deposition position of the ZnONs. TEM and XRD indicated that the ZnONs close to the reactor center, ZnON-A, has better crystalline structure than the ZnONs away from the center, ZnON-B. ZnON-A showed the PL and Raman spectra characteristic of perfect ZnO crystals, whereas ZnON-B produced very strong green emission band at 500 nm in the photoluminescence (PL) spectrum and very strong Raman scattering peak at 560 cm(-1), both related to the oxygen deficiency due to insufficient oxidation of zinc vapor. ZnON-B exhibited better field emission properties with higher emission current density and lower turn-on field than ZnON-A.

  8. New evidence on iron, copper accumulation and zinc depletion and its correlation with DNA integrity in aging human brain regions

    PubMed Central

    Vasudevaraju, P.; Bharathi; T, Jyothsna; Shamasundar, N. M.; Subba Rao, K.; Balaraj, B. M.; KSJ, Rao; T.S, Sathyanarayana Rao

    2010-01-01

    Deoxyribonucleic acid (DNA) conformation and stability play an important role in brain function. Earlier studies reported alterations in DNA integrity in the brain regions of neurological disorders like Parkinson’s and Alzheimer’s diseases. However, there are only limited studies on DNA stability in an aging brain and the factors responsible for genomic instability are still not clear. In this study, we assess the levels of Copper (Cu), Iron (Fe) and Zinc (Zn) in three age groups (Group I: below 40 years), Group II: between 41-60 years) and Group III: above 61 years) in hippocampus and frontal cortex regions of normal brains. The number of samples in each group was eight. Genomic DNA was isolated and DNA integrity was studied by nick translation studies and presented as single and double strand breaks. The number of single strand breaks correspondingly increased with aging compared to double strand breaks. The strand breaks were more in frontal cortex compared to hippocampus. We observed that the levels of Cu and Fe are significantly elevated while Zn is significantly depleted as one progresses from Group I to Group III, indicating changes with aging in frontal cortex and hippocampus. But the elevation of metals was more in frontal cortical region compared to hippocampal region. There was a clear correlation between Cu and Fe levels versus strand breaks in aging brain regions. This indicates that genomic instability is progressive with aging and this will alter the gene expressions. To our knowledge, this is a new comprehensive database to date, looking at the levels of redox metals and corresponding strand breaks in DNA in two brain regions of the aging brain. The biological significance of these findings with relevance to mental health will be discussed. PMID:20838501

  9. Zinc

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc was recognized as an essential trace metal for humans during the studies of Iranian adolescent dwarfs in the early 1960s. Zinc metal existing as Zn2+ is a strong electron acceptor in biological systems without risks of oxidant damage to cells. Zn2+ functions in the structure of proteins and is ...

  10. 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.

  11. Zinc

    MedlinePlus

    ... deficiency also causes hair loss, diarrhea, eye and skin sores and loss of appetite. Weight loss, problems ... pneumonia and other infections. Zinc also helps the skin stay healthy. Some people who have skin ulcers ...

  12. Structural and magnetic properties of chromium doped zinc ferrite

    SciTech Connect

    Sebastian, Rintu Mary; Thankachan, Smitha; Xavier, Sheena; Mohammed, E. M.; Joseph, Shaji

    2014-01-28

    Zinc chromium ferrites with chemical formula ZnCr{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by Sol - Gel technique. The structural as well as magnetic properties of the synthesized samples have been studied and reported here. The structural characterizations of the samples were analyzed by using X – Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The single phase spinel cubic structure of all the prepared samples was tested by XRD and FTIR. The particle size was observed to decrease from 18.636 nm to 6.125 nm by chromium doping and induced a tensile strain in all the zinc chromium mixed ferrites. The magnetic properties of few samples (x = 0.0, 0.4, 1.0) were investigated using Vibrating Sample Magnetometer (VSM)

  13. Microstructure and microwave dielectric properties of modified zinc titanates (II)

    SciTech Connect

    Kim, H.T. |; Byun, J.D.; Kim, Y.

    1998-06-01

    Zinc titanates ZnO-TiO{sub 2} (Zn/Ti = 0.67--2.0) and Zn{sub 1{minus}x}Mg{sub x}TiO{sub 3} (x = 0--0.4) were prepared by a conventional mixed-oxide method, and the microstructure and dielectric properties in the microwave range were investigated. In the ZnO-TiO{sub 2} system, zinc orthotitanate, Zn{sub 2}TiO{sub 4}, had rutile solubility up to 0.33 mol followed by a decrease in the cubic lattice parameters as the amount of rutile increased. The zero {tau}{sub f} was obtained near Zn/Ti = 1.15 composition. The {epsilon}{sub r} and Q*f of the composition were 25 and 23,000, respectively. In the Zn{sub 1{minus}x}Mg{sub x}TiO{sub 3} system, the composite structure with zinc orthotitanate and rutile of 1ZnO{center_dot}1TiO{sub 2} transformed into the (Zn, Mg)TiO{sub 3} hexagonal solid solution at x = 0.3--0.4. However, phase decomposition occurred in this range at a temperature above 1160 C, which induced microcracks and resulted in a decrease in Q factors. A range of dielectric resonators with {epsilon}{sub r} = 20--30, Q = 2,500--13,000 at GHz, and {tau}{sub f} = {minus}70 to +50 ppm/C can be obtained in this system at a sintering temperature as low as 1,100 C.

  14. Microstructure and microwave dielectric properties of modified zinc titanates (I)

    SciTech Connect

    Kim, H.T. |; Byun, J.D.; Kim, Y.

    1998-06-01

    Zinc metatitanate, ZnTiO{sub 3}, decomposes into zinc orthotitanate and rutile on heating above 945 C. It was found that this material could be a useful candidate for microwave resonator materials. The substitution of Zn by less than 10 mol% of Ba, Ca, or Sr achieves near zero {tau}{sub f} in spite of the fact that BaTiO{sub 3}, CaTiO{sub 3}, and SrTiO{sub 3} themselves have positive {tau}{sub f}. The origin of the temperature-compensating characteristics of the modified system was found to be in the reduction or elimination of rutile by the formation of new phases such as Ba{sub 3}Zn{sub 7}Ti{sub 12}O{sub 34}, Ca{sub 2}Zn{sub 4}Ti{sub 15}O{sub 36}, and Sr{sub 2}Zn{sub 4}Ti{sub 15}O{sub 36} polytitanates, which have much lower positive {tau}{sub f} than the rutile. It was revealed that zinc orthotitanate grains containing around 0.33 mol excess rutile have Zn{sub 2}Ti{sub 3}O{sub 8} nanosize precipitates in the grain. The precipitates had a structural coherency with the Zn{sub 2}TiO{sub 4} cubic matrix phase. The modified system has microwave dielectric properties of {epsilon}{sub r} = 25--32, Q factor at 10 GHz = 2,300--5,400, and {tau}{sub f} = +56 to {minus}22 ppm/C.

  15. Zinc Enzymes.

    ERIC Educational Resources Information Center

    Bertini, I.; And Others

    1985-01-01

    Discusses the role of zinc in various enzymes concerned with hydration, hydrolysis, and redox reactions. The binding of zinc to protein residues, properties of noncatalytic zinc(II) and catalytic zinc, and the reactions catalyzed by zinc are among the topics considered. (JN)

  16. Properties of zinc oxide at low and moderate temperatures

    NASA Astrophysics Data System (ADS)

    Lashkarev, G. V.; Karpyna, V. A.; Lazorenko, V. I.; Ievtushenko, A. I.; Shtepliuk, I. I.; Khranovskyy, V. D.

    2011-03-01

    The properties of zinc oxide are examined as an analog of gallium nitride over a wide range of temperatures and possible applications. Its economic and environmental advantages are noted, as well as its radiation hardness, compared to group III nitrides. Methods for growing films and nanostructures with high crystal perfection are proposed. In particular, a magnetron technique for layer-by-layer growth of films is implemented which makes it possible to obtain high structural perfection and substantial thicknesses unattainable by several other methods. The feasibility of producing monochromatic UV radiation from films excited by short-wavelength radiation and electrons is demonstrated; this means that they may be useable as short-wavelength radiation sources. Efficient field emission by ZnO nanostructures and films is demonstrated and opens up the prospect of their use in vacuum microelectronics equipment. Nitrogen-doped ZnO films, in particular, have been used to fabricate a phototransistor with a sensitivity two orders of magnitude higher than conventional detectors. The physical basis for creating LEDs for different colors based on ZnO films and solid solutions with CdO is discussed. The importance of studying the physics and technology of zinc oxide-based devices is emphasized.

  17. Structure-dependent mechanical properties of ultrathin zinc oxide nanowires

    PubMed Central

    2011-01-01

    Mechanical properties of ultrathin zinc oxide (ZnO) nanowires of about 0.7-1.1 nm width and in the unbuckled wurtzite (WZ) phase have been carried out by molecular dynamics simulation. As the width of the nanowire decreases, Young's modulus, stress-strain behavior, and yielding stress all increase. In addition, the yielding strength and Young's modulus of Type III are much lower than the other two types, because Type I and II have prominent edges on the cross-section of the nanowire. Due to the flexibility of the Zn-O bond, the phase transformation from an unbuckled WZ phase to a buckled WZ is observed under the tensile process, and this behavior is reversible. Moreover, one- and two-atom-wide chains can be observed before the ZnO nanowires rupture. These results indicate that the ultrathin nanowire possesses very high malleability. PMID:21711876

  18. Electromagnetic properties of manganese-zinc ferrite with lithium substitution

    NASA Astrophysics Data System (ADS)

    De Fazio, E.; Bercoff, P. G.; Jacobo, S. E.

    2011-11-01

    Polycrystalline manganese-zinc ferrite with lithium substitution of composition Li 0.5 xMn 0.4Zn 0.6- xFe 2+0.5 xO 4 (0.0≤ x≤0.4) was prepared by the usual ceramic method. X-ray diffraction analysis confirmed that the samples have a spinel structure and are of single phase for some values of Li content. Lithium doping considerably modifies saturation magnetization since its value increases from 57.5 emu/g for x=0.0 to 82.9 emu/g for x=0.4. Lithium inclusion increases the real permeability (over 1 MHz) while the natural resonance frequency shifts to lower values as the fraction of Li increases. These ferrites show good electromagnetic properties as absorbers in the microwave range of 1 MHz - 1 GHz.

  19. Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone

    NASA Astrophysics Data System (ADS)

    Evstrop'ev, S. K.; Gatchin, Yu. A.; Evstrop'ev, K. S.; Dukel'skii, K. V.; Kislyakov, I. M.

    2015-12-01

    Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of colloidal solutions in the UV spectral range are determined by the quantum-confinement effect, exhibiting a dependence of the absorption edge on the size of zinc sulfide nanocrystals.

  20. Scaling characteristics of depletion type, fully transparent amorphous indium-gallium-zinc-oxide thin-film transistors and inverters following Ar plasma treatment

    NASA Astrophysics Data System (ADS)

    Kim, Joonwoo; Jeong, Soon Moon; Jeong, Jaewook

    2015-11-01

    We fabricated depletion type, transparent amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) and inverters with an Ar plasma treatment and analyzed their scaling characteristics with channel lengths ranging from 2 to 100 µm. The improvement of the field-effect mobility of a-IGZO TFTs is apparent only for short channel lengths. There is also an unexpected side effect of the Ar plasma treatment, which introduces back-channel interfacial states and induces a positive shift in the threshold voltage of a-IGZO TFTs. The resulting increase in the field-effect mobility and the positive shift in the threshold voltage of each TFT increase the differential gain up to 3 times and the positive shift in the transient point of the transparent inverters.

  1. Synthesis and anticancer properties of water-soluble zinc ionophores.

    PubMed

    Magda, Darren; Lecane, Philip; Wang, Zhong; Hu, Weilin; Thiemann, Patricia; Ma, Xuan; Dranchak, Patricia K; Wang, Xiaoming; Lynch, Vincent; Wei, Wenhao; Csokai, Viktor; Hacia, Joseph G; Sessler, Jonathan L

    2008-07-01

    Several water-solubilized versions of the zinc ionophore 1-hydroxypyridine-2-thione (ZnHPT), synthesized as part of the present study, have been found both to increase the intracellular concentrations of free zinc and to produce an antiproliferative activity in exponential phase A549 human lung cancer cultures. Gene expression profiles of A549 cultures treated with one of these water-soluble zinc ionophores, PCI-5002, reveal the activation of stress response pathways under the control of metal-responsive transcription factor 1 (MTF-1), hypoxia-inducible transcription factor 1 (HIF-1), and heat shock transcription factors. Additional oxidative stress response and apoptotic pathways were activated in cultures grown in zinc-supplemented media. We also show that these water-soluble zinc ionophores can be given to mice at 100 micromol/kg (300 micromol/m(2)) with no observable toxicity and inhibit the growth of A549 lung and PC3 prostate cancer cells grown in xenograft models. Gene expression profiles of tumor specimens harvested from mice 4 h after treatment confirmed the in vivo activation of MTF-1-responsive genes. Overall, we propose that water-solubilized zinc ionophores represent a potential new class of anticancer agents.

  2. Depletions of sulfur and/or zinc in IDPs: Are they reliable indicators of atmospheric entry heating?

    NASA Astrophysics Data System (ADS)

    Flynn, G. J.; Sutton, S. R.; Bajt, S.; Kloeck, W.; Thomas, K. L.; Keller, L. P.

    1993-03-01

    The degree of heating of interplanetary dust particles (IDP's) on Earth atmospheric entry is important in distinguishing cometary particles from main-belt asteroidal particles. Depletions in the volatile elements S and Zn were proposed as chemical indicators of significant entry heating. The S and Zn contents of cosmic dust particles were correlated with physical indicators of atmospheric entry heating, such as the production of magnetite and the loss of solar wind implanted He. The results indicate that the Zn content of IDP's is a useful indicator of entry heating, but the S content seems to be less useful.

  3. Depletions of sulfur and/or zinc in IDPs: Are they reliable indicators of atmospheric entry heating?

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Sutton, S. R.; Bajt, S.; Kloeck, W.; Thomas, K. L.; Keller, L. P.

    1993-01-01

    The degree of heating of interplanetary dust particles (IDP's) on Earth atmospheric entry is important in distinguishing cometary particles from main-belt asteroidal particles. Depletions in the volatile elements S and Zn were proposed as chemical indicators of significant entry heating. The S and Zn contents of cosmic dust particles were correlated with physical indicators of atmospheric entry heating, such as the production of magnetite and the loss of solar wind implanted He. The results indicate that the Zn content of IDP's is a useful indicator of entry heating, but the S content seems to be less useful.

  4. Specific effects of maternal zinc depletion or repletion on the deposition of zinc and metallothionein in newborn rat livers: a longitudinal study

    SciTech Connect

    Gallant, K.R.; Cherian, M.G.

    1986-03-05

    High levels of metallothionein (MT) have been reported in association with elevated zinc (Zn) in the livers of newborn rats. Previous studies in this laboratory have demonstrated that maternal Zn-deficiency (Zn-D) specifically reduces the storage of Zn as MT in one day old pup liver. To further investigate how dietary Zn levels influence the storage of Zn as MT, newborn Zn-D pups were allowed to suckle from Zn-sufficient (Zn-S) dams and vice versa. Pups were injected with 2.5 ..mu..Ci of Zn/sup 65/ and whole body retention monitored. Pups were sacrificed at varying time periods up to weaning and hepatic levels of Zn and MT were measured. A gradual increase in the abnormally low hepatic levels of Zn and MT was observed in Zn-D pups suckling from Zn-S dams up to about day 10. Zn-S pups suckling from Zn-D dams showed a much faster rate of decline of MT and Zn than in age-matched controls, suggesting a rapid turnover of Zn-MT. Whole body retention of Zn/sup 65/ was lower in the Zn-repleted pups than in the pups which were subjected to Zn-D postnatally. These results demonstrate that the Zn-MT levels fluctuate directly in response to the Zn status of the pups, supporting the role of MT as a Zn storage protein in newborn rats.

  5. Zinc isotopic composition of iron meteorites: Absence of isotopic anomalies and origin of the volatile element depletion

    NASA Astrophysics Data System (ADS)

    Chen, Heng; Nguyen, Bach Mai; Moynier, Frédéric

    2013-12-01

    High-precision Zn isotopic compositions measured by MC-ICP-MS are documented for 32 iron meteorites from various fractionally crystallized and silicate-bearing groups. The δ66Zn values range from -0.59‰ up to +5.61‰ with most samples being slightly enriched in the heavier isotopes compared with carbonaceous chondrites (0 < δ66Zn < 0.5). The δ66Zn versus δ68Zn plot of all samples defines a common linear fractionation line, which supports the hypothesis that Zn was derived from a single reservoir or from multiple reservoirs linked by mass-dependent fractionation processes. Our data for Redfields fall on a mass fractionation line and therefore refute a previous claim of it having an anomalous isotopic composition due to nonmixing of nucleosynthetic products. The negative correlation between δ66Zn and the Zn concentration of IAB and IIE is consistent with mass-dependent isotopic fractionation due to evaporation with preferential loss of lighter isotopes in the vapor phase. Data for the Zn concentrations and isotopic compositions of two IVA samples demonstrate that volatile depletion in the IVA parent body is not likely the result of evaporation. This is important evidence that favors the incomplete condensation origin for the volatile depletion of the IVA parent body.

  6. Synthesis, characterization, and optical properties of zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Andelman, Tamar

    Chapter 1. A general introduction is presented that describes the new interdisciplinary field of nanoscience. The various unique properties of nanocrystals are highlighted, and different nanocrystal synthetic techniques are discussed. The importance of a technique that achieves control over nanocrystal size and morphology is stressed. Morphological control over zinc oxide nanocrystals using the "thermal decomposition of metal acetates" method is discussed. The numerous possible morphologies of nanocrystals of zinc oxide are described to illustrate the suitability of ZnO for a study of the relationship between nanocrystal morphology and properties. Chapter 2. A study of the growth, structure, self organization properties, and photoluminescence, of ZnO nanorods with 2 nm diameter is presented. The disparity in relative intensity of X-ray diffraction peaks between the ZnO nanorods and bulk ZnO is modeled using XRD refinement software, and shown to arise from preferred orientation, which occurs due to the nanorod shape. The effect of various synthesis parameters---reaction time, and capping agent to precursor molar ratio---on the nanorod growth and structure is probed using synchrotron X-ray diffraction by monitoring the width and position of the (002) diffraction peak. The stacking properties of the nanorods are studied using small angle X-ray diffraction, which can probe larger scale ordering due to the small angles used. The photoluminescence properties are studied using solution photoluminescence measurements, and strong quantum confinement effects are observed, due to the small diameter of the nanorods. Chapter 3. Morphological control of ZnO nanocrystals based on the coordinating power of the solvent used is presented. The various nano-shapes (nanotriangles, spherical nanoparticles, and nanorods) are studied by TEM and XRD. Using tilting TEM experiments and CrystalMaker models, the three dimensional nature of the nanotriangles is determined. Solution

  7. Properties of Transparent Zinc-Tin Oxide Conducting Films Prepared by Chemical Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Martinez, Arturo I.; Garcia, Benjamin A.; Acosta, Dwight R.

    2005-06-01

    In this work we have prepared thin films of zinc-tin oxide by the chemical spray pyrolysis method. The structural, electrical and optical properties were studied for all films as a function of the zinc content in the starting solution, yielding values of electrical resistivity (ρ), Hall mobility (μ), carrier concentration (n), and optical transmission (T) suitable for optoelectronic applications, e.g. our optimal values were ρ = 3.56×10-2 Ω cm and T = 0.77.

  8. Effect of high dietary zinc on plasma ceruloplasmin and erythrocyte superoxide dismutase activities in copper-depleted and repleted rats.

    PubMed

    Panemangalore, M; Bebe, F N

    1996-01-01

    The effect of moderately high dietary zinc (Zn) on the activities of plasma (PL) ceruloplasmin (CP), and PL and erythrocyte (RBC) copper (Cu), Zn superoxide dismutase (SOD) was determined in weanling rats fed Cu-deficient (DEF; < 1 mg Cu/kg), marginal (MAR; 2 mg Cu/kg), or control (CON; 5 mg Cu/kg) copper diets containing normal or high Zn (HZn; 60 mg/kg) for 4 wk and supplemented with oral Cu (CuS; 5 mg/L) in drinking water for 0, 1, 3, or 7 d. PL Cu decreased (67% compared to CON; p < or = 0.05) in the DEF and increased to control level after 3 d of CuS; increased in the MAR group after 1 d of CuS. HZn reduced overall PL Cu by 27% in all groups, but did not alter the linear increase in PL Cu between 0 and 3 d of Cu S. PL CP activity altered concomitantly with PL Cu levels: The time course of increase in CP activity after 0-3 d of CuS was not influenced by HZn in the diet and CP declined in the DEF group by 92%. There was no correlation between dietary Cu level and PL CP. PL SOD activity decreased by 46% (p < or = .05) in the DEF group, increased to control activity after 1 d of CuS and declined slightly after 7 d; MAR diet did not alter PL SOD. HZn diet increased PL SOD activity in all groups by 150%, reduced activity in the DEF and MAR groups by 65 and 37% and delayed the recovery of PL SOD after CuS. RBC SOD declined in the DEF and MAR groups by 56 and 33% (p < or = 0.05) and did not respond to CuS; HZn diet did not influence RBC SOD activity. These data indicate that moderately high Zn in the diet reduces PL Cu, but not PL CP activity or the recovery of PL Cu or CP activity after oral CuS of Cu-deficient rats, modifies the response of PL SOD to dietary Cu, but does not influence RBC SOD activity.

  9. Optoelectronic Properties of Color-Tunable Mixed Ligand-Based Light-Emitting Zinc Complexes

    NASA Astrophysics Data System (ADS)

    Singh, Devender; Bhagwan, Shri; Saini, Raman Kumar; Tanwar, Vijeta; Nishal, Vandna

    2016-10-01

    A series of mixed ligand-based zinc complexes (Zn1-Zn5); [(8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn1), [(5-chloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn2), [(5,7-dichloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn3), [(2-methyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn4) and [(5,7-dimethyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn5) were synthesized and characterized. The photophysical properties of zinc complexes were examined by ultraviolet-visible absorption and photoluminescence emission spectroscopy. All prepared metal complexes produced intense luminescence on excitation with a UV light source. In this study, the color-tunable characteristics of metal complexes were investigated by introducing the electron-donating and electron-withdrawing groups on the 8-hydroxyquinoline ligand. The emission spectra of metal complexes showed emission wavelength at 500 nm for [ZnHBI(q)], 509 nm for [ZnHBI(Clq)], 504 nm for [Zn(HBI)(Cl2q)], 496 nm for [ZnHBI (Meq)] and 573 nm for [ZnHBI(Me2Q)] materials. A temperature-dependent PL spectrum was used to study the emission profile of zinc complex and observed that variation in the temperature altered the position and the intensity of emission peak. The synthesized metal complex also exhibited good thermal stability (>300°C). Photophysical characteristics of color-tunable light-emitting zinc complexes suggested that these materials could be efficiently used for emissive display device applications.

  10. Antibacterial properties of composite resins incorporating silver and zinc oxide nanoparticles on Streptococcus mutans and Lactobacillus

    PubMed Central

    Kasraei, Shahin; Sami, Lida; Hendi, Sareh; AliKhani, Mohammad-Yousef; Rezaei-Soufi, Loghman

    2014-01-01

    Objectives Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans and Lactobacillus. Materials and Methods Ninety discoid tablets containing 0%, 1% nano-silver and 1% nano zinc-oxide particles were prepared from flowable composite resin (n = 30). The antibacterial properties of composite resin discs were evaluated by direct contact test. Diluted solutions of Streptococcus mutans (PTCC 1683) and Lactobacillus (PTCC 1643) were prepared. 0.01 mL of each bacterial species was separately placed on the discs. The discs were transferred to liquid culture media and were incubated at 37℃ for 8 hr. 0.01 mL of each solution was cultured on blood agar and the colonies were counted. Data was analyzed with Kruskall-Wallis and Mann-Whitney U tests. Results Composites containing nano zinc-oxide particles or silver nanoparticles exhibited higher antibacterial activity against Streptococcus mutans and Lactobacillus compared to the control group (p < 0.05). The effect of zinc-oxide on Streptococcus mutans was significantly higher than that of silver (p < 0.05). There were no significant differences in the antibacterial activity against Lactobacillus between composites containing silver nanoparticles and those containing zinc-oxide nanoparticles. Conclusions Composite resins containing silver or zinc-oxide nanoparticles exhibited antibacterial activity against Streptococcus mutans and Lactobacillus. PMID:24790923

  11. Development of zinc oxide nanoparticle by sonochemical method and study of their physical and optical properties

    NASA Astrophysics Data System (ADS)

    Khan, Samreen Heena; Suriyaprabha, R.; Pathak, Bhawana; Fulekar, M. H.

    2016-04-01

    With the miniaturization of crystal size, the fraction of under-coordinated surface atoms becomes dominant, and hence, materials in the nano-regime behave very differently from the similar material in a bulk. Zinc oxide (ZnO), particularly, exhibits extraordinary properties such as a wide direct band gap (3.37 eV), large excitation binding energy (60 meV), low refractive index (1.9), stability to intense ultraviolet (UV) illumination, resistance to high-energy irradiation, and lower toxicity as compared to other semiconductors. This very property makes Zinc Oxide a potential candidate in many application fields, particularly as a prominent semiconductor. Zinc Oxide plays a significant role in many technological advances with its application in semiconductor mediated photocatalytic processes and sensor, solar cells and others. In present study, Zinc Oxide (ZnO) has been synthesized using three different precursors by sonochemical method. Zinc Acetate Dihydrate, Zinc Nitrate Hexahydrate and Zinc Sulphate Heptahydrate used as a precursor for the synthesis process. The synthesized ZnO nanoparticle has been found under the range of ˜50 nm. Zinc oxide nanoparticles were characterized using different characterizing tools. The as-synthesized ZnO was characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) for the determination of functional group; Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS) for Morphology and elemental detection respectively, Transmission Electron Microscopy for Particle size distribution and morphology and X-Ray Diffraction (XRD) for the confirmation of crystal structure of the nanomaterial. The optical properties of the ZnO were examined by UV-VIS spectroscopy equipped with Diffuse Reflectance spectroscopy (DRS) confirmed the optical band gap of ZnO-3 around 3.23 eV resembles with the band gap of bulk ZnO (3.37eV). The TEM micrograph of the as-synthesized material showed perfectly spherical shaped

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

    SciTech Connect

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

    2010-04-15

    Zinc borate (2ZnO.3B{sub 2}O{sub 3}.3.5H{sub 2}O) 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{sub 2}O{sub 3}.3.5H{sub 2}O) nanoflakes by employing solid-liquid reaction of zinc oxide (ZnO) and boric acid (H{sub 3}BO{sub 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. - Graphical abstract: The contact angle of hydrophobic zinc borate nanoflakes is 129.02 deg. with added 2.0 wt% of oleic acid.

  13. Spectroscopic and catalytic properties of Rhus vernicifera laccase depleted in type 2 copper.

    PubMed

    Reinhammar, B; Oda, Y

    1979-10-01

    1. The type 2 copper in Rhus vernicifera laccase was completely removed without loss of other types of copper. The properties of this protein derivative and the role of type 2 copper in the catalytic action of laccase was investigated. 2. The molar extinction coefficient at 614 nm of the blue chromophore decreases from 5700 to 4700 cm-1 on removal of type 2 copper. There are no apparent absorption changes at other wavelengths in the visible or near ultraviolet region when this copper is taken away. The electron-paramagnetic-resonance (epr) parameter A parallel and the linewidth of type 1 Cu2+ decreases on removal of type 2 copper. 3. The rate of reduction of type 1 Cu2+ is not affected by removal of type 2 copper but the reduction of the two-electron acceptor is greatly impaired. These results strongly support the idea that type 1 Cu2+ is the primary site for electron transfer between substrate and enzyme and that the two-electron acceptor in the native enzyme is reduced by simultaneous electron transfer from reduced types 1 and 2 copper. 4. Reoxidation of types 1 and 3 copper and the formation of the oxygen intermediate are the same processes in native and type-2-depleted enzyme. These observations suggests that type 2 copper is not involved in the formation and rapid decay of the oxygen intermediate and that it is not necessary for the stabilization of this intermediate. 5. Two new epr signals are observed on reoxidation of reduced type-2-depleted laccase. One is temporarily formed on re-reduction of reoxidized enzyme and it is suggested that it might arise from copper, possibly type 3 copper. The other one is stable for hours and it is proposed that it might come from a modified oxygen intermediate. PMID:228004

  14. Third order nonlinear optical properties of bismuth zinc borate glasses

    SciTech Connect

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.

    2013-12-28

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

  15. Spectral and Luminescent Properties of N-(3-Methoxysalicylidene)- o-anisidine and Its Zinc Complex

    NASA Astrophysics Data System (ADS)

    Puzyk, M. V.; Baichurin, R. I.; Borisov, A. N.

    2016-03-01

    The synthesis and the spectral and luminescent properties of N-(3-methoxysalicylidene)- o-anisidine and its Zn(II) complex are presented. It is found that Schiff base in solution has the E( anti)-configuration, and the zinc complex fluoresces in solution and the polycrystalline state at 77 and 293 K.

  16. Fabrication of zinc oxide microstructures and their properties

    NASA Astrophysics Data System (ADS)

    Kumari, Latha; Li, Wenzhi; Vannoy, Charles H.; Leblanc, Roger M.; Wang, Dezhi

    2009-03-01

    The bitter-melon-like and prism-like zinc oxide (ZnO) microstructures have been synthesized by hydrothermal route. Besides these microstructures, the ZnO material also consists of spherical nanoparticles with narrow size distribution. The as-synthesized ZnO material depicts hexagonal crystal structure. An optical band gap of 2.95 eV is determined from the UV-vis absorption band edge. The prism-like ZnO microstructure shows an ultraviolet near-band-edge emission at about 3.27 eV (380 nm) at room temperature which can be assigned to the radiative annihilation of excitons. The wide-band gap oxide materials like ZnO with short-wavelength PL emission can find application in light emitting devices.

  17. 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.

  18. Physicochemical properties of the zinc-containing dusts of electric furnace steelmaking

    NASA Astrophysics Data System (ADS)

    Korneev, V. P.; Sirotinkin, V. P.; Petrakova, N. V.; Dyubanov, V. G.; Leont'ev, L. I.

    2013-07-01

    The properties of the dusts of electric-arc melting in the Severstal' metallurgical works are studied by X-ray diffraction, Mössbauer spectroscopy, and electron microscopy. The elemental compositions of dust particles of various sizes are determined, and the complex structural composition of iron-containing oxide phases is revealed. It is shown that, in these systems, the carbon reduction of zinc from zincite is possible in the solid state in the temperature range 600-1000°C. In this case, zinc passes into a gaseous phase and iron oxides are reduced to form metallic iron.

  19. Different properties of aluminum doped zinc oxide nanostructured thin films prepared by radio frequency magnetron sputtering

    SciTech Connect

    Bidmeshkipour, Samina Shahtahmasebi, Nasser

    2013-06-15

    Aluminium doped zinc oxide (AZO) nanostructured thin films are prepared by radio frequency magnetron sputtering on glass substrate using specifically designed ZnO target containing different amount of Al{sub 2}O{sub 3} powder as the Al doping source. The optical properties of the aluminium doped zinc oxide films are investigated. The topography of the deposited films were investigated by Atomic Force Microscopy. Variation of the refractive index by annealing temperature are considered and it is seen that the refractive index increases by increasing the annealing temperature.

  20. 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.

  1. Effect of solvents on the synthesis of nano-size zinc oxide and its properties

    SciTech Connect

    Kanade, K.G.; Kale, B.B. . E-mail: kbbb1@yahoo.com; Aiyer, R.C.; Das, B.K.

    2006-03-09

    The effect of the solvents on particle size and morphology of ZnO is investigated. The optical properties of nano ZnO were studied extensively. During this study, zinc oxalate was prepared in aqueous and organic solvents using zinc acetate and oxalic acid as precursors. The thermo-gravimetric analysis (TGA/DTA) showed formation of ZnO at 400 deg. C. Nano-size zinc oxide was obtained by thermal decomposition of aqueous and organic mediated zinc oxalate at 450 deg. C. The phase purity was confirmed by XRD and crystal size determined from transmission electron microscopy (TEM) was found to be 22-25 nm for the aqueous and 14 -17 nm in organic mediated ZnO. Scanning electron microscope (SEM) also revealed different nature of surfaces and microstructures for zinc oxide obtained in aqueous and organic solvents. The UV absorption spectra showed sharp absorption peaks with a blue shift for organic mediated ZnO, due to monodispersity and lower particle size. Sharp peaks and absence of any impurity peaks in photoluminescence spectra (PLS) complement the above observations.

  2. Facile fabrication and supercapacitive properties of mesoporous zinc cobaltite microspheres

    NASA Astrophysics Data System (ADS)

    Wang, Qinghong; Du, Jialu; Zhu, Yuxuan; Yang, Jiaqin; Chen, Juan; Wang, Chao; Li, Liang; Jiao, Lifang

    2015-06-01

    Mesoporous zinc cobaltite (ZnCo2O4) microspheres have been successfully prepared by a facile solvothermal method followed by an annealing process. The as-prepared ZnCo2O4 displays uniform sphere-like morphology composed of interconnected ZnCo2O4 nanoparticles. The Brunauer-Emmett-Teller (BET) surface area of mesoporous ZnCo2O4 microspheres is about 51.4 m2 g-1 with dominant pore diameter of 7.5 nm. The novel ZnCo2O4 material exhibits high specific capacitance of 953.2 F g-1 and 768.5 F g-1 at discharge current densities of 4 A g-1 and 30 A g-1, respectively. The energy density can be estimated to be 26.68 Wh kg-1 at a power density of 8 kW kg-1. The specific capacitance retention is 97.8% after 3000 cycles, suggesting its excellent cycling stability. The superior electrochemical performance is mainly attributed to the uniformity of the surface structure and the porosity of the microspheres, which benefit electrons and ions transportation, provide large electrode-electrolyte contact area, and meanwhile reduce volume change during the charge-discharge process. This method of constructing porous microspheres is very effective, yet simple, and it could be applied in other high-performance metal oxide electrode materials for electrochemical capacitors, as well as in Li-ion batteries.

  3. Influence of quencher on microstructure and magnetic properties of manganese-zinc ferrites

    NASA Astrophysics Data System (ADS)

    Lezhong, Li; Zhongwen, Lan; Zhong, Yu; Ke, Sun; Haining, Ji

    2007-11-01

    The effects of quencher after calcination on the microstructure and magnetic properties of manganese-zinc ferrites were investigated by measuring the magnetic properties, electrical resistivity and density. The powder of Mn 0.68Zn 0.25Fe 2.07O 4 composition was prepared by adopting the conventional ceramic technique. Toroidal cores were sintered at 1350 °C for 4 h in atmosphere controlled by using the equation for equilibrium oxygen partial pressure. The fracture surface micrographs of samples were observed by scanning electron microscope. The results show that the inner stress of calcined powder increases, abnormal grains of ferrite grow up, initial permeability goes down and power losses of ferrite rise with the increase in quenching temperature, and the microstructure and magnetic properties of manganese-zinc ferrites can be improved with the gradual cooling of calcined powder to room temperature (25 °C).

  4. Properties, use and health effects of depleted uranium (DU): a general overview.

    PubMed

    Bleise, A; Danesi, P R; Burkart, W

    2003-01-01

    Depleted uranium (DU), a waste product of uranium enrichment, has several civilian and military applications. It was used as armor-piercing ammunition in international military conflicts and was claimed to contribute to health problems, known as the Gulf War Syndrome and recently as the Balkan Syndrome. This led to renewed efforts to assess the environmental consequences and the health impact of the use of DU. The radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher. Due to the low specific radioactivity and the dominance of alpha-radiation no acute risk is attributed to external exposure to DU. The major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU. Since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons. Urine, feces, hair and nails record recent exposures to DU. With the exception of crews of military vehicles having been hit by DU penetrators, no body burdens above the range of values for natural uranium have been found. Therefore, observable health effects are not expected and residual cancer risk estimates have to be based on theoretical considerations. They appear to be very minor for all post-conflict situations, i.e. a fraction of those expected from natural radiation.

  5. Synthesis and dielectric properties of zinc oxide nanoparticles using a biotemplate

    SciTech Connect

    P, Sharmila P; Tharayil, Nisha J.

    2014-10-15

    Zinc Oxide nanoparticles are synthesized using DNA as capping agent. Zinc oxide nanoparticles are synthesized using DNA as a capping agent. Structural and morphological characterizations are done using SEM, FTIR and XRD. The particle size and lattice parameters are calculated from the diffraction data. The optical properties are studied using UV-Vis absorption spectroscopy and bandgap variation with temperature is determined. The dielectric property of nanoparticles is studied by varying temperature and frequency. The dielectric constant and dispersion parameters are found out. Method of Cole-Cole analysis is used to study the high temperature dispersion of relaxation time. The variation of both AC and DC conductivity are studied and activation energy calculated.

  6. Synthesis and dielectric properties of zinc oxide nanoparticles using a biotemplate

    NASA Astrophysics Data System (ADS)

    P, Sharmila P.; Tharayil, Nisha J.

    2014-10-01

    Zinc Oxide nanoparticles are synthesized using DNA as capping agent. Zinc oxide nanoparticles are synthesized using DNA as a capping agent. Structural and morphological characterizations are done using SEM, FTIR and XRD. The particle size and lattice parameters are calculated from the diffraction data. The optical properties are studied using UV-Vis absorption spectroscopy and bandgap variation with temperature is determined. The dielectric property of nanoparticles is studied by varying temperature and frequency. The dielectric constant and dispersion parameters are found out. Method of Cole-Cole analysis is used to study the high temperature dispersion of relaxation time. The variation of both AC and DC conductivity are studied and activation energy calculated.

  7. Spectral reflectance properties of electroplated and converted zinc for use as a solar selective coating

    NASA Technical Reports Server (NTRS)

    Mcdonald, G. E.; Curtis, H. B.; Gianelos, L.

    1975-01-01

    The spectral reflectance properties of electroplated and chemically converted zinc were measured for both chromate and chloride conversion coatings. The reflectance properties were measured for various times of conversion and for conversion at various chromate concentrations. The values of absorptance, integrated over the solar spectrum, and of infrared emittance, integrated over black body radiation at 250 F were then calculated from the measured reflectance values. The interdependent variations of absorptance and infrared emittance were plotted. The results indicate that the optimum combination of the highest absorptance in the solar spectrum and the lowest emittance in the infrared of the converted electroplated zinc is produced by chromate conversion at 1/2 concentration of the standard NEOSTAR chromate black solution for 0.50 minute or by chloride conversion for 0.50 minute.

  8. Biosynthesis of silver and zinc oxide nanoparticles using Pichia fermentans JA2 and their antimicrobial property

    NASA Astrophysics Data System (ADS)

    Chauhan, Ritika; Reddy, Arpita; Abraham, Jayanthi

    2015-01-01

    The development of eco-friendly alternative to chemical synthesis of metal nanoparticles is of great challenge among researchers. The present study aimed to investigate the biological synthesis, characterization, antimicrobial study and synergistic effect of silver and zinc oxide nanoparticles against clinical pathogens using Pichia fermentans JA2. The extracellular biosynthesis of silver and zinc oxide nanoparticles was investigated using Pichia fermentans JA2 isolated from spoiled fruit pulp bought in Vellore local market. The crystalline and stable metallic nanoparticles were characterized evolving several analytical techniques including UV-visible spectrophotometer, X-ray diffraction pattern analysis and FE-scanning electron microscope with EDX-analysis. The biosynthesized metallic nanoparticles were tested for their antimicrobial property against medically important Gram positive, Gram negative and fungal pathogenic microorganisms. Furthermore, the biosynthesized nanoparticles were also evaluated for their increased antimicrobial activities with various commercially available antibiotics against clinical pathogens. The biosynthesized silver nanoparticles inhibited most of the Gram negative clinical pathogens, whereas zinc oxide nanoparticles were able to inhibit only Pseudomonas aeruginosa. The combined effect of standard antibiotic disc and biosynthesized metallic nanoparticles enhanced the inhibitory effect against clinical pathogens. The biological synthesis of silver and zinc oxide nanoparticles is a novel and cost-effective approach over harmful chemical synthesis techniques. The metallic nanoparticles synthesized using Pichia fermentans JA2 possess potent inhibitory effect that offers valuable contribution to pharmaceutical associations.

  9. Anticancer nanodelivery system with controlled release property based on protocatechuate–zinc layered hydroxide nanohybrid

    PubMed Central

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Abd Gani, Shafinaz; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-01-01

    Background We characterize a novel nanocomposite that acts as an efficient anticancer agent. Methods This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors. Results The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines. Conclusion PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer. PMID:25061291

  10. Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

    NASA Astrophysics Data System (ADS)

    Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

    2016-10-01

    With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

  11. Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

    NASA Astrophysics Data System (ADS)

    Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

    2016-08-01

    With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

  12. Origin of electrochemical, structural and transport properties in non-aqueous zinc electrolytes

    DOE PAGESBeta

    Han, Sang -Don; Rajput, Nav Nidhi; Qu, Xiaohui; Pan, Baofei; He, Meinan; Ferrandon, Magali S.; Liao, Chen; Persson, Kristin A.; Burrell, Anthony K.

    2016-01-14

    Through coupled experimental analysis and computational techniques, we uncover the origin of anodic stability for a range of nonaqueous zinc electrolytes. By examination of electrochemical, structural, and transport properties of nonaqueous zinc electrolytes with varying concentrations, it is demonstrated that the acetonitrile Zn(TFSI)2, acetonitrile Zn(CF3SO3)2, and propylene carbonate Zn(TFSI)2 electrolytes can not only support highly reversible Zn deposition behavior on a Zn metal anode (≥99% of Coulombic efficiency), but also provide high anodic stability (up to ~3.8 V). The predicted anodic stability from DFT calculations is well in accordance with experimental results, and elucidates that the solvents play an importantmore » role in anodic stability of most electrolytes. Molecular dynamics (MD) simulations were used to understand the solvation structure (e.g., ion solvation and ionic association) and its effect on dynamics and transport properties (e.g., diffusion coefficient and ionic conductivity) of the electrolytes. Lastly, the combination of these techniques provides unprecedented insight into the origin of the electrochemical, structural, and transport properties in nonaqueous zinc electrolytes« less

  13. Piezoelectric properties of zinc oxide nanowires: an ab initio study

    NASA Astrophysics Data System (ADS)

    Korir, K. K.; Cicero, G.; Catellani, A.

    2013-11-01

    Nanowires made of materials with non-centrosymmetric crystal structures are expected to be ideal building blocks for self-powered nanodevices due to their piezoelectric properties, yet a controversial explanation of the effective operational mechanisms and size effects still delays their real exploitation. To solve this controversy, we propose a methodology based on DFT calculations of the response of nanostructures to external deformations that allows us to distinguish between the different (bulk and surface) contributions: we apply this scheme to evaluate the piezoelectric properties of ZnO [0001] nanowires, with a diameter up to 2.3 nm. Our results reveal that, while surface and confinement effects are negligible, effective strain energies, and thus the nanowire mechanical response, are dependent on size. Our unified approach allows for a proper definition of piezoelectric coefficients for nanostructures, and explains in a rigorous way the reason why nanowires are found to be more sensitive to mechanical deformation than the corresponding bulk material.

  14. Physical properties of zinc doped tin oxide films prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Vijayalakshmi, S.; Venkataraj, S.; Subramanian, M.; Jayavel, R.

    2008-02-01

    The structural and optical properties of pure and zinc doped tin oxide (SnO2) thin films have been studied in detail. Thin films of pure and zinc doped tin oxide (Zn : SnO2) were prepared on Si(1 0 0) and quartz substrates by the spray pyrolysis technique at a substrate temperature of 400 °C. The zinc dopant concentration was varied from 0 to 25 wt%. The films were systematically characterized by different methods to understand their structural and optical property variations, and the results were correlated. The x-ray diffraction (XRD) method shows that pure SnO2 films possess tetragonal crystalline structure with the preferred (1 1 0) orientation. Upon increasing the zinc concentration the preferred orientation changes from the (1 1 0) plane to the (2 0 0) plane, and at the same time the crystalline quality was found to be deteriorated. The Raman measurements also confirm the tetragonal structure of the films for the entire range of Zn doping. High resolution scanning electron microscopy measurements reveal that upon increasing the Zn concentration, the surface morphology of the films changes continuously and the grains also deteriorate. The elemental analysis of the films measured by energy dispersive XRD spectroscopy shows that the Zn concentration in the solid film is slightly less than that of the starting solution. Optical transmittance measurements of the films reveal that the films are fully transparent in the visible region. Upon increasing the Zn concentration, the band gap of the films decreases from 3.85 to 3.57 eV. Thus, the structural study performed by XRD and Raman spectroscopy clearly indicates the incorporation of Zn ion into SnO2 lattice, and the change in the optical properties of the films was directly attributed to the effect of Zn ion incorporation into SnO2 lattice.

  15. Piezoelectric properties of zinc oxide nanowires: an ab initio study.

    PubMed

    Korir, K K; Cicero, G; Catellani, A

    2013-11-29

    Nanowires made of materials with non-centrosymmetric crystal structures are expected to be ideal building blocks for self-powered nanodevices due to their piezoelectric properties, yet a controversial explanation of the effective operational mechanisms and size effects still delays their real exploitation. To solve this controversy, we propose a methodology based on DFT calculations of the response of nanostructures to external deformations that allows us to distinguish between the different (bulk and surface) contributions: we apply this scheme to evaluate the piezoelectric properties of ZnO [0001] nanowires, with a diameter up to 2.3 nm. Our results reveal that, while surface and confinement effects are negligible, effective strain energies, and thus the nanowire mechanical response, are dependent on size. Our unified approach allows for a proper definition of piezoelectric coefficients for nanostructures, and explains in a rigorous way the reason why nanowires are found to be more sensitive to mechanical deformation than the corresponding bulk material. PMID:24177806

  16. Synthesis, characterization and photocatalytic properties of novel zinc germanate nano-materials

    SciTech Connect

    Boppana, Venkata Bharat Ram; Hould, Nathan D.; Lobo, Raul F.

    2011-05-15

    We report the first instance of a hydrothermal synthesis of zinc germanate (Zn{sub 2}GeO{sub 4}) nano-materials having a variety of morphologies and photochemical properties in surfactant, template and catalyst-free conditions. A systematic variation of synthesis conditions and detailed characterization using X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Raman spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and small angle X-ray scattering led to a better understanding of the growth of these particles from solution. At 140 {sup o}C, the zinc germanate particle morphology changes with pH from flower-shaped at pH 6.0, to poly-disperse nano-rods at pH 10 when the Zn to Ge ratio in the synthesis solution is 2. When the Zn to Ge ratio is reduced to 1.25, mono-disperse nano-rods could be prepared at pH 7.5. Nanorod formation is also independent of the addition of cetyltrimethylammonium bromide (CTAB), in contrast to previous reports. Photocatalytic tests show that Zn{sub 2}GeO{sub 4} nano-rods (by weight) and flower shaped (by surface area) are the most active for methylene blue dye degradation among the synthesized zinc germanate materials. -- Graphical abstract: Zinc germanate materials were synthesized possessing unique morphologies dependent on the hydrothermal synthesis conditions in the absence of surfactant, catalyst or template. These novel materials are characterized and evaluated for their photocatalytic activities. Display Omitted highlights: > Zinc germanate synthesized hydrothermally (surfactant free) with unique morphologies. > Flower-shaped, nano-rods, globular particles obtained dependent on synthesis pH. > At 140 {sup o}C, they possess the rhombohedral crystal irrespective of synthesis conditions. > They are photocatalytically active for the degradation of methylene blue. > Potential applications could be photocatalytic water splitting and CO{sub 2} reduction.

  17. Influence of doping with third group oxides on properties of zinc oxide thin films

    SciTech Connect

    Palimar, Sowmya Bangera, Kasturi V.; Shivakumar, G. K.

    2013-03-15

    The study of modifications in structural, optical and electrical properties of vacuum evaporated zinc oxide thin films on doping with III group oxides namely aluminum oxide, gallium oxide and indium oxide are reported. It was observed that all the films have transmittance ranging from 85 to 95%. The variation in optical properties with dopants is discussed. On doping the film with III group oxides, the conductivity of the films showed an excellent improvement of the order of 10{sup 3} {Omega}{sup -1} cm{sup -1}. The measurements of activation energy showed that all three oxide doped films have 2 donor levels below the conduction band.

  18. Structural and optical properties of zinc oxide film using RF-sputtering technique

    SciTech Connect

    Hashim, A. J.; Jaafar, M. S.; Ghazai, Alaa J.

    2012-11-27

    This paper reports the fabrication of zinc oxide (ZnO) film using RF-sputtering technique. Determination of the structural properties using High Resolution X-ray Diffraction (HRXRD) confirmed that ZnO film deposited on silicon (Si) substrate has a high quality. This result is in line with the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) which were used to image the morphology of the film, in which a rough surface was demonstrated. Photoluminescence (PL) emission is included to study the optical properties of ZnO film that shows two PL peak in the UV region at 371 nm and in visible region at 530 nm respectively.

  19. Microwave absorption properties of Mn- and Ni-doped zinc oxides

    SciTech Connect

    Wu Qibai; Zhao Wei; Zeng Guoxun; Zhang Haiyan; Wei Aixiang; Wang Jia

    2011-05-15

    Microwave absorption properties of Mn- and Ni-doped zinc oxides were assessed in this study. Samples were prepared by the decomposition of acetate solid solutions. By changing the concentration of dopant ions in the reaction solutions, zinc oxides with different amounts of dopant were obtained. The morphologies, chemical compositions, and structures of the samples were investigated by scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray powder diffraction. Electromagnetic characteristics of the doped samples were assessed by vector network analysis at a frequency range of 2-16 GHz. Both the real and imaginary parts of the complex permittivity decreased as Mn or Ni concentration increased. Results indicate that, compared with pure ZnO, Mn- and Ni-doped zinc oxides exhibit excellent microwave absorption properties. The highest level of microwave absorption observed was 80.7 dB at a frequency of 9.8 GHz, and the best frequency bandwidth was 8.6 GHz at reflection loss values below -10 dB.

  20. Optical properties of single wurtzite/zinc-blende ZnSe nanowires grown at low temperature

    SciTech Connect

    Zannier, V.; Cremel, T.; Kheng, K.; Artioli, A.; Ferrand, D.; Grillo, V.

    2015-09-07

    ZnSe nanowires with a dominant wurtzite structure have been grown at low temperature (300 °C) by molecular beam epitaxy assisted by solid Au nanoparticles. The nanowires emission is polarized perpendicularly to their axis in agreement with the wurtzite selection rules. Alternations of wurtzite and zinc-blende regions have been observed by transmission electron microscopy, and their impact on the nanowires optical properties has been studied by microphotoluminescence. The nanowires show a dominant intense near-band-edge emission as well as the ZnSe wurtzite free exciton line. A type II band alignment between zinc-blende and wurtzite ZnSe is evidenced by time-resolved photoluminescence. From this measurement, we deduce values for the conduction and valence band offsets of 98 and 50 meV, respectively.

  1. Cadmium and Zinc Alloyed Cu-In-S Nanocrystals and Their Optical Properties

    PubMed Central

    Huang, Liming; Zhu, Xiaoshan; Publicover, Nelson G.; Hunter, Kenneth W.; Ahmadiantehrani, Mojtaba; de Bettencourt-Dias, Ana; Bell, Thomas W.

    2013-01-01

    Cadmium (Cd) and zinc (Zn) alloyed copper-indium-sulfide (Cu-In-S or CIS) nanocrystals (NCs) in several nanometers were prepared using thermal decomposition methods, and the effects of Cd and Zn on optical properties, including the tuning of NC photoluminescence (PL) wavelength and quantum yield (QY), were investigated. It was found that incorporation of Cd into CIS enhances the peak QY of NCs whereas zinc alloying diminishes the peak. In contrast with Zn alloying, Cd alloying does not result in a pronounced luminescence blue shift. The further PL decay study suggests that Cd alloying reduces surface or intrinsic defects whereas alloying with Zn increases the overall number of defects. PMID:24409089

  2. Influence of oxygen depletion layer on the properties of tin oxide gas-sensing films fabricated by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Natarajan, Gomathi; Cameron, David C.

    2009-06-01

    In this paper we report on the influence of film thickness on the electrical and gas-sensing properties of tin oxide thin films grown by atomic layer deposition (ALD) technique. The nature of the carrier and post-flow gases used in ALD was found to have a dramatic influence on the electrical conductance of the deposited films. Up to a film thickness of 50 nm the sheet conductance of the films increased with the thickness, and above 50 nm the sheet conductance was not significantly influenced by the film thickness. This effect was attributed to oxygen depletion at the film surface. When the depth of oxygen depletion ( d dep) was greater than or equal to the film thickness ( t), the sheet conductance was thickness dependant. On the other hand, when d dep≤ t, the sheet conductance was independent of the film thickness but depended on the depth of the oxygen depletion. This proposed explanation was verified by subjecting the films to different lengths of post-annealing in an oxygen depleted atmosphere. Gas-sensing functionality of the films with various thicknesses was examined. It was observed that the film thickness had a significant influence on the gas-sensing property of the films. When the thickness was greater than 40 nm, the sensitivity of the films to ethanol was found to follow the widely reported trend, i.e., the sensitivity decreases when the film thickness increases. Below the film thickness of 40 nm the sensitivity decreases as film thickness decreases, and we propose a model to explain this observation based on the increase in resistance due to multiple grain boundaries.

  3. Effects of Li and Cu dopants on structural properties of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Ho; Jin, Zhuguang; Abe, Yoshio; Kawamura, Midori

    2015-01-01

    We fabricated undoped zinc oxide (ZnO), Li-doped zinc oxide (LZO), and Cu-doped zinc oxide (CZO) nanorods (NRs) on fluorine-doped tin oxide (FTO)-coated glass substrates using chemical solution deposition and investigated their structural properties. With the incorporation of the Li dopant, the length and crystallinity of LZO NRs increased and improved, respectively, compared to that of the ZnO NRs. The average optical transmittance of LZO NRs was slightly lower than that of the ZnO NRs, but otherwise very similar over the visible wavelength region. With the incorporation of the Cu dopant, however, the morphology of the CZO sample was remarkably different from that of the pure ZnO NRs. Rods with a length of ∼12 μm and a diameter of 0.5-1.2 μm were randomly oriented on the substrate, and copper oxide (CuO) nanocrystals were uniformly grown on the surface of substrate. This paper presents a simple way to tune the growth behaviors of the ZnO NRs by adding dopants.

  4. Effects of Natural Organic Matter Properties on the Dissolution Kinetics of Zinc Oxide Nanoparticles.

    PubMed

    Jiang, Chuanjia; Aiken, George R; Hsu-Kim, Heileen

    2015-10-01

    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.

  5. Semiconducting properties of zinc-doped cubic boron nitride thin films

    SciTech Connect

    Nose, K.; Yoshida, T.

    2007-09-15

    We have examined the electronic properties of zinc-doped cubic boron nitride (cBN) thin films prepared by sputter deposition. The electric conductivity of films deposited in pure Ar increased as the concentration of zinc dopant increased, and hole conduction was identified by the measurement of thermoelectric currents. It was also found that the conductivity increment in such films was accompanied by a linear increase in the B/(B+N) ratio. At the same time, no modification of the composition and the conductivity by incorporated zinc was observed when film growth took place in presence of nitrogen gas. The effect of the excess boron on the conductivity emerged only when films show semi-insulating behavior. These results suggest that Zn substitution for nitrogen causes high electric conductivity of cBN. The electric contact between Ti electrode and semiconducting cBN was examined by the transfer length method, and Ohmic conduction was observed in the Ti/cBN contact. The specific contact resistance was affected by the specific resistance of cBN films, and it was reduced from 10{sup 5} to 100 {omega} cm{sup 2} by increasing the concentration of incorporated Zn.

  6. Pencil-like zinc oxide micro/nano-scale structures: Hydrothermal synthesis, optical and photocatalytic properties

    SciTech Connect

    Moulahi, A.; Sediri, F.

    2013-10-15

    Graphical abstract: - Highlights: • Zinc oxide micro/nanopencils have been synthesized hydrothermally. • Photocatalytic activity has been evaluated by the degradation of methylene blue under UV light irradiation. • ZnO nanopencils exhibit much higher photocatalytic activity than the commercial ZnO. - Abstract: Zinc oxide micro/nanopencils have been successfully synthesized by hydrothermal process using zinc acetate and diamines as structure-directing agents. The morphology, the structure, the crystallinity and the composition of the materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The optical properties of synthesized ZnO were investigated by UV–vis spectroscopy. The photocatalytic activity of the material has been evaluated by the degradation of methylene blue under UV irradiation. As a result, after the lapse of 150 min, around 82% bleaching was observed, with ZnO nanopencils yielding more photodegradation compared to that of commercial ZnO (61%)

  7. Property enhancement by grain refinement of zinc-aluminium foundry alloys

    NASA Astrophysics Data System (ADS)

    Krajewski, W. K.; Greer, A. L.; Piwowarski, G.; Krajewski, P. K.

    2016-03-01

    Development of cast alloys with good mechanical properties and involving less energy consumption during their melting is one of the key demands of today's industry. Zinc foundry alloys of high and medium Al content, i.e. Zn-(15-30) wt.% Al and Zn-(8-12) wt.% Al, can satisfy these requirements. The present paper summarizes the work [1-9] on improving properties of sand-cast ZnAl10 (Zn-10 wt.% Al) and ZnAl25 (Zn-25 wt. % Al) alloys by melt inoculation. Special attention was devoted to improving ductility, whilst preserving high damping properties at the same time. The composition and structural modification of medium- and high-aluminium zinc alloys influence their strength, tribological properties and structural stability. In a series of studies, Zn - (10-12) wt. % Al and Zn - (25-26) wt.% Al - (1-2.5) wt.% Cu alloys have been doped with different levels of added Ti. The melted alloys were inoculated with ZnTi-based refiners and it was observed that the dendritic structure is significantly finer already after addition of 50 - 100 ppm Ti to the melted alloys. The alloy's structure and mechanical properties have been studied using: SEM (scanning electron microscopy), LM (light microscopy), dilatometry, pin-on-disc wear, and tensile strength measurements. Grain refinement leads to significant improvement of ductility in the binary high-aluminium Zn-(25-27) Al alloys while in the medium-aluminium alloys the effect is rather weak. In the ternary alloys Zn-26Al-Cu, replacing a part of Cu with Ti allows dimensional changes to be reduced while preserving good tribological properties. Furthermore, the high initial damping properties were nearly entirely preserved after inoculation. The results obtained allow us to characterize grain refinement of the examined high-aluminium zinc alloys as a promising process leading to the improvement of their properties. At the same time, using low melting ZnTi-based master alloys makes it possible to avoid the excessive melt overheating

  8. Luminescence properties of some double-activated zinc-sulphide-type phosphors

    NASA Astrophysics Data System (ADS)

    Popovici, Elisabeth-Jeanne; Aneculaese, Maria; Ursu, Veronica

    1998-07-01

    Silver and copper double activated phosphor samples were synthesized from zinc sulphide prepared by thiosulphate method and with a NaCl-MgCl2 mixture as flux. The thermal treatment was performed in a protective atmosphere at 900 - 1100 degree(s)C. The samples were characterized by crystalline structure (XRD patterns) and luminescent properties (emission spectra, decay curves). An intensification effect of the copper green fluorescence by silver ions was put in evidence. Conditions for a good green emitting phosphor were established.

  9. Microstructure and optoelectronic properties of galliumtitanium-zinc oxide thin films deposited by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Chen, Shou-bu; Lu, Zhou; Zhong, Zhi-you; Long, Hao; Gu, Jin-hua; Long, Lu

    2016-07-01

    Gallium-titanium-zinc oxide (GTZO) transparent conducting oxide (TCO) thin films were deposited on glass substrates by radio frequency magnetron sputtering. The dependences of the microstructure and optoelectronic properties of GTZO thin films on Ar gas pressure were observed. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results show that all the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. With the increment of Ar gas pressure, the microstructure and optoelectronic properties of GTZO thin films will be changed. When Ar gas pressure is 0.4 Pa, the deposited films possess the best crystal quality and optoelectronic properties.

  10. Density functional theory description of electronic properties of wurtzite zinc oxide

    NASA Astrophysics Data System (ADS)

    Franklin, L.; Ekuma, C. E.; Zhao, G. L.; Bagayoko, D.

    2013-05-01

    We report calculated, electronic properties of wurtzite zinc oxide (w-ZnO). We solved self-consistently the two inherently coupled equations of density functional theory (DFT), following the Bagayoko, Zhao, and Williams (BZW) method as enhanced by the work of Ekuma and Franklin (BZW-EF). We employed a local density approximation (LDA) potential and the linear combination of atomic orbitals (LCAO). Most of the calculated, electronic properties of w-ZnO are in excellent agreement with experiment, including our zero temperature band gap of 3.39 eV and the electron effective mass. The doubly self-consistent approach utilized in this work points to the ability of theory to predict accurately key properties of semiconductors and hence to inform and to guide the design and fabrication of semiconductor-based devices.

  11. Zinc: the neglected nutrient.

    PubMed

    Shambaugh, G E

    1989-03-01

    Zinc was first recognized as essential for animals at the University of Illinois School of Agriculture in 1916, when it was found that zinc-deficient baby pigs were runty, developed dermatitis on their legs, and were sterile. Zinc deficiency was first recognized in man by Dr. Ananda Prasad of Detroit 26 years ago when he measured serum and hair zinc levels in young male Egyptian dwarfs who had failed to mature and were small in stature. By simply adding zinc to their regular diet, they grew in height and became sexually mature. It is now recognized that dwarfism in males is frequent around the Mediterranean, where wheat is the staple of life and has been grown for 4,000 years on the same soil, thereby resulting in the depletion of zinc. Professor Robert Henkin first suggested that zinc deficiency might cause hearing-nerve impairment. Assay of the soft tissues of the cochlea and vestibule revealed a zinc level higher than that of any other part of the body. Previously, the eye was considered to have the highest level of zinc of any organ. To diagnose zinc deficiency clinically, we use serum zinc assays made at the Mayo Clinic Trace Element Laboratory. With zinc supplementation in patients who are marginally zinc deficient, there has been improvement in tinnitus and sensorineural hearing loss in about one-third of elderly adults. We believe zinc deficiency is one causation of presbycusis; by recognizing and correcting it, a progressive hearing loss can be arrested.

  12. Zinc: the neglected nutrient.

    PubMed

    Shambaugh, G E

    1989-03-01

    Zinc was first recognized as essential for animals at the University of Illinois School of Agriculture in 1916, when it was found that zinc-deficient baby pigs were runty, developed dermatitis on their legs, and were sterile. Zinc deficiency was first recognized in man by Dr. Ananda Prasad of Detroit 26 years ago when he measured serum and hair zinc levels in young male Egyptian dwarfs who had failed to mature and were small in stature. By simply adding zinc to their regular diet, they grew in height and became sexually mature. It is now recognized that dwarfism in males is frequent around the Mediterranean, where wheat is the staple of life and has been grown for 4,000 years on the same soil, thereby resulting in the depletion of zinc. Professor Robert Henkin first suggested that zinc deficiency might cause hearing-nerve impairment. Assay of the soft tissues of the cochlea and vestibule revealed a zinc level higher than that of any other part of the body. Previously, the eye was considered to have the highest level of zinc of any organ. To diagnose zinc deficiency clinically, we use serum zinc assays made at the Mayo Clinic Trace Element Laboratory. With zinc supplementation in patients who are marginally zinc deficient, there has been improvement in tinnitus and sensorineural hearing loss in about one-third of elderly adults. We believe zinc deficiency is one causation of presbycusis; by recognizing and correcting it, a progressive hearing loss can be arrested. PMID:2786676

  13. Zinc-metallothionein genoprotective effect is independent of the glutathione depletion in HaCaT keratinocytes after solar light irradiation.

    PubMed

    Jourdan, Eric; Marie Jeanne, Richard; Régine, Steiman; Pascale, Guiraud

    2004-06-01

    UV radiations are the major environmental factors that induce DNA damage of skin cells either by direct absorption (UVB), or after inducing an oxidative stress (UVA and UVB). Cells maintain a reducing intracellular environment to avoid genomic damage. MTs have been expected not only to control metal homeostasis but also counteract the glutathione (GSH) depletion induced by oxidative stress because of their high thiol content. Induction and redistribution of MTs in cultured human keratinocytes (HaCaT) in response to SSL, is an important cellular defense mechanism against DNA damage. Reduced glutathione (GSH) is another way of cellular protection against UV-induced oxidative stress. This study which extend our previous finding focused on the relation between intracellular GSH and Zn genoprotective effects after solar irradiation. HaCaT cells, depleted or not in GSH by a chemical treatment were used to compare MTs induction by Northern blot, expression by Western blot and localization using immunocytochemistry. Zn genoprotection experiments after SSL irradiation was carried out by the comet assay. We demonstrated that in absence of GSH, Zn-MTs could protect DNA after SSL irradiation and that GSH depletion has no effect on MTs induction and localization. Nuclear Zn-MTs could be responsible for this observed genoprotection in GSH depleted cells. So the GSH/Zn and the MT/Zn systems could be two independent but interacting mechanisms of cellular protection against SSL injury.

  14. Optical properties of Sm3+ ions in zinc potassium fluorophosphate glasses

    NASA Astrophysics Data System (ADS)

    Thomas, Sunil; George, Rani; Nayab Rasool, Sk.; Rathaiah, M.; Venkatramu, V.; Joseph, Cyriac; Unnikrishnan, N. V.

    2013-12-01

    In the present work, different concentrations of Sm3+ ions doped zinc potassium fluorophosphate glasses (PKAMZFSm: P2O5 + K2O + MgO + Al2O3 + ZnF2 + Sm2O3) were synthesized via melt quench technique. Physical properties and refractive indices of the present glasses were evaluated. Optical characterization of Sm3+: PKAMZF glasses through absorption, excitation, emission and decay spectra had been carried out. Nephelauxetic ratios, bonding parameter and energy band gap of the 1.0 mol% Sm3+-doped PKAMZF glass were evaluated using absorption spectra. Judd-Ofelt (JO) intensity analysis had been presented and JO parameters were evaluated for 1.0 mol% Sm3+-doped zinc potassium fluorophosphate glass. Radiative properties such as transition probabilities, branching ratios and radiative lifetime were estimated by using JO parameters. Stimulated emission cross-sections and effective bandwidths of each transition were obtained from the luminescence spectra. The experimental lifetime, quantum efficiency and donor-acceptor interaction parameters were also estimated using decay curves of 4G5/2 level of Sm3+ ions in the present glasses. The influence of Sm3+ ion concentrations on the luminescence intensity, lifetime and energy transfer parameters for PKAMZFSm glasses was investigated. The results obtained have been compared with the other Sm3+-doped glasses.

  15. Nonlinear optical properties of zinc oxide doped bismuth thin films using Z-scan technique

    NASA Astrophysics Data System (ADS)

    Abed, S.; Bouchouit, K.; Aida, M. S.; Taboukhat, S.; Sofiani, Z.; Kulyk, B.; Figa, V.

    2016-06-01

    ZnO doped Bi thin films were grown on glass substrates by spray ultrasonic technique. This paper presents the effect of Bi doping concentration on structural and nonlinear optical properties of zinc oxide thin films. These thin films were characterized by X-ray diffractometer technique. XRD analysis revealed that the ZnO:Bi thin films indicated good preferential orientation along c-axis perpendicular to the substrate. The nonlinear optical properties such as nonlinear absorption coefficient (β) and third order nonlinear susceptibility (Imχ(3)) are investigated. The calculations have been performed with a Z scan technique using Nd:YAG laser emitting 532 nm. The reverse saturable absorption (RSA) mechanism was responsible for the optical limiting effect. The results suggest that this material considered as a promising candidate for future optical device applications.

  16. Zinc Oxide Nanorods Shielded with an Ultrathin Nickel Layer: Tailoring of Physical Properties

    PubMed Central

    Mudusu, Devika; Nandanapalli, Koteeswara Reddy; Dugasani, Sreekantha Reddy; Park, Sung Ha; Tu, Charles W.

    2016-01-01

    We report on the development of Ni-shielded ZnO nanorod (NR) structures and the impact of the Ni layer on the ZnO NR properties. We developed nickel-capped zinc oxide nanorod (ZnO/Ni NR) structures by e-beam evaporation of Ni and the subsequent annealing of the ZnO/Ni core/shell nanostructures. The core/shell NRs annealed at 400 °C showed superior crystalline and emission properties. More interestingly, with the increase of annealing temperature, the crystallinity of the Ni shells over the ZnO NRs gradually changed from polycrystalline to single crystalline. The presence of the Ni layer as a polycrystalline shell completely hindered the light emission and transmission of the ZnO NR cores. Further, the band gap of ZnO NRs continuously decreased with the increase of annealing temperature. PMID:27334555

  17. Zinc Oxide Nanorods Shielded with an Ultrathin Nickel Layer: Tailoring of Physical Properties

    NASA Astrophysics Data System (ADS)

    Mudusu, Devika; Nandanapalli, Koteeswara Reddy; Dugasani, Sreekantha Reddy; Park, Sung Ha; Tu, Charles W.

    2016-06-01

    We report on the development of Ni-shielded ZnO nanorod (NR) structures and the impact of the Ni layer on the ZnO NR properties. We developed nickel-capped zinc oxide nanorod (ZnO/Ni NR) structures by e-beam evaporation of Ni and the subsequent annealing of the ZnO/Ni core/shell nanostructures. The core/shell NRs annealed at 400 °C showed superior crystalline and emission properties. More interestingly, with the increase of annealing temperature, the crystallinity of the Ni shells over the ZnO NRs gradually changed from polycrystalline to single crystalline. The presence of the Ni layer as a polycrystalline shell completely hindered the light emission and transmission of the ZnO NR cores. Further, the band gap of ZnO NRs continuously decreased with the increase of annealing temperature.

  18. Zinc-dependent mechanical properties of Staphylococcus aureus biofilm-forming surface protein SasG

    PubMed Central

    Formosa-Dague, Cécile; Speziale, Pietro; Foster, Timothy J.; Geoghegan, Joan A.; Dufrêne, Yves F.

    2016-01-01

    Staphylococcus aureus surface protein SasG promotes cell–cell adhesion during the accumulation phase of biofilm formation, but the molecular basis of this interaction remains poorly understood. Here, we unravel the mechanical properties of SasG on the surface of living bacteria, that is, in its native cellular environment. Nanoscale multiparametric imaging of living bacteria reveals that Zn2+ strongly increases cell wall rigidity and activates the adhesive function of SasG. Single-cell force measurements show that SasG mediates cell–cell adhesion via specific Zn2+-dependent homophilic bonds between β-sheet–rich G5–E domains on neighboring cells. The force required to unfold individual domains is remarkably strong, up to ∼500 pN, thus explaining how SasG can withstand physiological shear forces. We also observe that SasG forms homophilic bonds with the structurally related accumulation-associated protein of Staphylococcus epidermidis, suggesting the possibility of multispecies biofilms during host colonization and infection. Collectively, our findings support a model in which zinc plays a dual role in activating cell–cell adhesion: adsorption of zinc ions to the bacterial cell surface increases cell wall cohesion and favors the projection of elongated SasG proteins away from the cell surface, thereby enabling zinc-dependent homophilic bonds between opposing cells. This work demonstrates an unexpected relationship between mechanics and adhesion in a staphylococcal surface protein, which may represent a general mechanism among bacterial pathogens for activating cell association. PMID:26715750

  19. Zinc- and oxidative property-dependent degradation of pro-caspase-1 and NLRP3 by ziram in mouse macrophages.

    PubMed

    Muroi, Masashi; Tanamoto, Ken-ichi

    2015-06-15

    The NLRP3 inflammasome, composed of caspase-1, NLRP3 and ASC, plays a critical role in the clearance of microbial pathogens. Here, we found that the treatment of mouse macrophages with the zinc-containing dithiocarbamate ziram, a widely used fungicide in agriculture, caused a decrease in pro-caspase-1 and NLRP3 levels while not affecting ASC level. Ziram did not affect levels of pro-caspase-1 and NLRP3 mRNA, and no cleavage products of pro-caspase-1 including p10 subunit, which is an autocleavage product of pro-caspase-1, were detected, indicating that the decrease was associated with degradation of these proteins. The decrease was inhibited by SH-type antioxidants, N-acetyl cysteine, dithiothreitol and 2-mercaptoethanol, or a metal chelator EDTA but not by inhibitors of proteasome, lysosomes, autophagy and matrix metalloproteases. Thiram, a comparator for ziram that does not contain zinc, showed a weaker decrease in protein levels. Furthermore, the zinc-containing dithiocarbamate, zinc diethyldithiocarbamate, efficiently decreased the levels of pro-caspase-1 and NLRP3, whereas dithiocarbamates, dimethyldithiocarbamate and diethyldithiocarbamate without zinc, were less active. The organic zinc compound [3,4-toluenedithiolato(2-)]zinc hydrate did not induce a decrease in protein levels. Ziram also inhibited IL-1β production by macrophages in response to lipopolysaccharide and bacterial clearance during Salmonella infection of macrophage cells. These results indicate that ziram causes degradation of pro-caspase-1 and NLRP3 in a zinc- and oxidative property-dependent manner and suggest that exposure to ziram may compromise the clearance of microbial pathogens. PMID:25929180

  20. Investigation of the Electronic Properties of Cadmium Zinc Telluride (CZT) Detectors using a Nuclear Microprobe

    SciTech Connect

    BRUNETT,BRUCE A.; DOYLE,BARNEY L.; JAMES,RALPH B.; VIZKELETHY,GYORGY; WALSH,DAVID S.

    1999-10-18

    The electronic transport properties of Cadmium Zinc Telluride (CZT) determine the charge collection efficiency (i.e. the signal quality) of CZT detectors. These properties vary on both macroscopic and microscopic scale and depend on the presence of impurities and defects introduced during the crystal growth. Ion Beam Induced Charge Collection (IBICC) is a proven method to measure the charge collection efficiency. Using an ion microbeam, the charge collection efficiency can be mapped with submicron resolution, and the map of electronic properties (such as drift length) can be calculated from the measurement. A more sophisticated version of IBICC, the Time Resolved IBICC (TRIBICC) allows them to determine the mobility and the life time of the charge carriers by recording and analyzing the transient waveform of the detector signal. Furthermore, lateral IBICC and TRIBICC can provide information how the charge collection efficiency depends on the depth where the charge carriers are generated. This allows one to deduce information on the distribution of the electric field and transport properties of the charge carriers along the detector axis. IBICC and TRIBICC were used at the Sandia microbeam facility to image electronic properties of several CZT detectors. From the lateral TRIBICC measurement the electron and hole drift length profiles were calculated.

  1. Electrical and optical properties of molybdenum doped zinc oxide films prepared by reactive RF magnetron sputtering

    SciTech Connect

    Reddy, R. Subba; Sreedhar, A.; Uthanna, S.

    2015-08-28

    Molybdenum doped zinc oxide (MZO) films were deposited on to glass substrates held at temperatures in the range from 303 to 673 K by reactive RF magnetron sputtering method. The chemical composition, crystallographic structure and surface morphology, electrical and optical properties of the films were determined. The films contained the molybdenum of 2.7 at. % in ZnO. The films deposited at 303 K were of X-ray amorphous. The films formed at 473 K were of nanocrystalline in nature with wurtzite structure. The crystallite size of the films was increased with the increase of substrate temperature. The optical transmittance of the films was in the visible range was 80–85%. The molybdenum (2.7 at %) doped zinc oxide films deposited at substrate temperature of 573 K were of nanocrystalline with electrical resistivity of 7.2×10{sup −3} Ωcm, optical transmittance of 85 %, optical band gap of 3.35 eV and figure of merit 30.6 Ω{sup −1}cm{sup −1}.

  2. Structural and antimicrobial properties of irradiated chitosan and its complexes with zinc

    NASA Astrophysics Data System (ADS)

    Khan, Azam; Mehmood, Shaukat; Shafiq, Muhammad; Yasin, Tariq; Akhter, Zareen; Ahmad, Shabir

    2013-10-01

    The aim of this research was to evaluate the structural and antimicrobial properties of irradiated chitosan and its complexes with zinc. Chitosan having a molecular weight (Mη) of 220 kDa was exposed to gamma rays in dry, wet and solution forms. The chitosan-zinc complexes were prepared by varying the Mη of chitosan and Zn content. Viscometeric analysis revealed a sharp decrease in the Mη of chitosan irradiated in solution form even at lower doses compared with the dry and wet forms. X-ray diffraction patterns demonstrated variation in the crystallinity of chitosan upon exposure to gamma rays. The antibacterial response of the irradiated chitosan and its complexes against gram-positive and gram-negative bacteria demonstrated wide spectrum of effective antimicrobial activities, which increased with the dose. Additionally, the complexes exhibited excellent antifungal activity with no growth of Aspergallious fumigatus and Fusarium solani even after two weeks. These results suggested that the irradiated chitosan and its complexes with Zn can be used as antimicrobial additives for various applications.

  3. Structure-property-composition relationships in doped zinc oxides: enhanced photocatalytic activity with rare earth dopants.

    PubMed

    Goodall, Josephine B M; Illsley, Derek; Lines, Robert; Makwana, Neel M; Darr, Jawwad A

    2015-02-01

    In this paper, we demonstrate the use of continuous hydrothermal flow synthesis (CHFS) technology to rapidly produce a library of 56 crystalline (doped) zinc oxide nanopowders and two undoped samples, each with different particle properties. Each sample was produced in series from the mixing of an aqueous stream of basic zinc nitrate (and dopant ion or modifier) solution with a flow of superheated water (at 450 °C and 24.1 MPa), whereupon a crystalline nanoparticle slurry was rapidly formed. Each composition was collected in series, cleaned, freeze-dried, and then characterized using analytical methods, including powder X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, X-ray photoelectron spectroscopy, and UV-vis spectrophotometry. Photocatalytic activity of the samples toward the decolorization of methylene blue dye was assessed, and the results revealed that transition metal dopants tended to reduce the photoactivity while rare earth ions, in general, increased the photocatalytic activity. In general, low dopant concentrations were more beneficial to having greater photodecolorization in all cases.

  4. Effects of physicochemical properties of zinc oxide nanoparticles on cellular uptake

    NASA Astrophysics Data System (ADS)

    Yu, J.; Baek, M.; Chung, H. E.; Choi, S. J.

    2011-07-01

    Zinc oxide (ZnO) nanoparticles have been used as a source of zinc, an essential trace element in food industry and also widely applied to various cosmetic products. However, there are few researches demonstrating that the cellular uptake behaviours of ZnO with respect to the physicochemical characteristics such as particle size and surface charge in human cells. In this study, we evaluated the cellular uptake of ZnO with two different sizes (20 and 70 nm) and different charges (positive and negative). Human lung epithelial cells were exposed to ZnO for a given time, and then the uptake amount of ZnO was measured with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results showed that the smaller sized ZnO could more easily enter the cells than the larger sized ZnO. In terms of surface charge, positively charged ZnO showed high cellular uptake compared to ZnO with negative charge. The internalization pathway of positively charged ZnO nanoparticles was determined to be primarily related to the energy-dependent endocytosis. It is, therefore, concluded that the particle size and surface charge of ZnO nanoparticles are critical factors influencing on their cellular uptake. Understanding the cellular uptake behaviours of nanoparticles with respect to physicochemical properties may be important to predict their toxicity potential on human.

  5. Structural and photoluminescence properties of terbium-doped zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Ningthoujam Surajkumar, Singh; Shougaijam Dorendrajit, Singh; Sanoujam Dhiren, Meetei

    2014-05-01

    We present in this paper a study of the structural and photoluminescence (PL) properties of terbium (Tb) doped zinc oxide (ZnO) nanoparticles synthesized by a simple low temperature chemical precipitation method, using zinc acetate and terbium nitrate in an isopropanol medium with diethanolamine (DEA) as the capping agent at 60 °C. The as-prepared samples were heat treated and the PL of the annealed samples were studied. The prepared nanoparticles were characterized with X-ray diffraction (XRD). The XRD patterns show the pattern of typical ZnO nanoparticles and correspond with the standard XRD pattern given by JCPDS card No. 36-1451, showing the hexagonal phase structure. The PL intensity was enhanced due to Tb3+ doping, and it decreased at higher concentrations of Tb3+ doping after reaching a certain optimum concentration. The PL spectra of Tb3+ doped samples exhibited blue, bluish green, and green emissions at 460 nm (5D3 - 7F3), 484 nm (5D4 - 7F6), and 530 nm (5D4 - 7F5), respectively, which were more intense than the emissions for the undoped ZnO sample. Based on the results, an energy level schematic diagram was proposed to explain the possible electron transition processes.

  6. Tailoring the optical and hydrophobic property of zinc oxide nanorod by coating with amorphous graphene

    NASA Astrophysics Data System (ADS)

    Pahari, D.; Das, N. S.; Das, B.; Chattopadhyay, K. K.; Banerjee, D.

    2016-09-01

    Zinc oxide (ZnO) nanorods were synthesized at room temperature on potassium permanganate activated silicon and glass substrate by simple chemical method using zinc acetate as precursor. To modify the surface energy of the as prepared ZnO thin films the samples were coated with amorphous graphene (a-G) synthesized by un-zipping of chemically synthesized amorphous carbon nanotubes (a-CNTs). All the pure and coated samples were characterized by x-ray diffraction, field emission scanning electron microscope, Raman spectroscopy, and Fourier transformed infrared spectroscopy. The roughness analysis of the as prepared samples was done by atomic force microscopic analysis. The detail optical properties of all the samples were studied with the help of a UV-Visible spectrophotometer. The surface energy of the as prepared pure and coated samples was calculated by measuring the contact angle of two different liquids. It is seen that the water repellence of ZnO nanorods got increased after they are being coated with a-Gs. Also even after UV irradiation the contact angle remain same unlike the case for the uncoated sample where the contact angle gets decreased significantly after UV irradiation. Existing Cassie-Wenzel model has been employed along with the Owen's approach to determine the different components of surface energy.

  7. Enhanced microwave absorption properties in cobalt-zinc ferrite based nanocomposites

    NASA Astrophysics Data System (ADS)

    Poorbafrani, A.; Kiani, E.

    2016-10-01

    In an attempt to find a solution to the problem of the traditional spinel ferrite used as the microwave absorber, the Co0.6Zn0.4Fe2O4-Paraffin nanocomposites were investigated. Cobalt-zinc ferrite powders, synthesized through PVA sol-gel method, were combined with differing concentrations of Paraffin wax. The nanocomposite samples were characterized employing various experimental techniques including X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Alternating Gradient Force Magnetometer (AGFM), and Vector Network Analyzer (VNA). The saturation magnetization and coercivity were enhanced utilizing appropriate stoichiometry, coordinate agent, and sintering temperature required for the preparation of cobalt-zinc ferrite. The complex permittivity and permeability spectra, and Reflection Loss (RL) of Co0.6Zn0.4Fe2O4-Paraffin nanocomposites were measured in the frequency range of 1-18 GHz. The microwave absorption properties of nanocomposites indicated that the absorbing composite containing 20 wt% of paraffin manifests the strongest microwave attenuation ability. The composite exhibited the reflection loss less than -10 dB in the whole C-band and 30% of the X-band frequencies.

  8. 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.

  9. Electrical properties of tin-doped zinc oxide nanostructures doped at different dopant concentrations

    NASA Astrophysics Data System (ADS)

    Nasir, M. F.; Zainol, M. N.; Hannas, M.; Mamat, M. H.; Rahman, S. A.; Rusop, Mohamad

    2016-07-01

    This project has been focused on the electrical and optical properties respectively on the effect of Tin doped zinc oxide (ZnO) thin films at different dopant concentrations. These thin films were doped with different Sn dopant concentrations at 1 at%, 2 at%, 3 at%, 4 at% and 5 at% was selected as the parameter to optimize the thin films quality while the annealing temperature is fixed 500 °C. Sn doped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thin films were characterized using Current Voltage (I-V) measurement and ultraviolet-visible-near-infrared (UV-vis-NIR) spectrophotometer (Perkin Elmer Lambda 750) for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 4 at% Sn doping concentration with the value 3.08 × 103 Ωcm-1. The absorption coefficient spectrum obtained shows all films exhibit very low absorption in the visible (400-800nm) and near infrared (NIR) (>800nm) range but exhibit high absorption in the UV range.

  10. Electrical properties of undoped zinc oxide nanostructures at different annealing temperature

    NASA Astrophysics Data System (ADS)

    Nasir, M. F.; Zainol, M. N.; Hannas, M.; Mamat, M. H.; Rahman, S. A.; Rusop, Mohamad

    2016-07-01

    This project has been focused on the electrical and optical properties respectively on the effect of Undoped zinc oxide (ZnO) thin films at different annealing temperature which is varied 400 °C, 450 °C, 500 °C, and 550 °C.Undoped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thin films were characterized using Current Voltage (I-V) measurement and UV-vis-NIR spectrophotometer for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 500 °C which its resistivity is 5.36 × 104 Ωcm-1. The absorption coefficient spectrum obtained from UV-Vis-NIR spectrophotometer measurement shows all films exhibit very low absorption in the visible (400-800nm) and near infrared (NIR) (>800nm) range but exhibit high absorption in the UV range.

  11. Hydrothermal Synthesis and Acetylene Sensing Properties of Variety Low Dimensional Zinc Oxide Nanostructures

    PubMed Central

    Chen, Weigen; Peng, Shudi; Zeng, Wen

    2014-01-01

    Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), glycine, and ethylene glycol (EG) play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2), one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2 sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2 gas sensor for practical application. PMID:24672324

  12. Controlled growth and field emission properties of zinc oxide nanopyramid arrays

    NASA Astrophysics Data System (ADS)

    Chen, Hongsheng; Qi, Junjie; Zhang, Yue; Zhang, Xiaomei; Liao, Qingliang; Huang, Yunhua

    2007-09-01

    Single-crystalline, pyramidal zinc oxide nanorods have been synthesized in a large quantity on p-Si substrate via catalyst-free thermal chemical vapor deposition at low temperature. SEM investigations showed that the nanorods were vertically aligned on the substrate, with diameters ranging from 60 to 80 nm and lengths about 1.5 μm. A self-catalysis VLS growth mechanism was proposed for the formation of the ZnO nanorods. The field emission properties of the ZnO nanopyramid arrays were investigated. A turn-on field about 3.8 V/μm was obtained at a current density of 10 μA/cm 2, and the field emission data was analyzed by applying the Fowler-Nordheim theory. The stability of emission current density under a high voltage was also tested, indicating that the ZnO nanostructures are promising for an application such as field emission sources.

  13. Manganese modified structural and optical properties of zinc soda lime silica glasses.

    PubMed

    Samsudin, Nur Farhana; Matori, Khamirul Amin; Wahab, Zaidan Abdul; Fen, Yap Wing; Liew, Josephine Ying Chi; Lim, Way Foong; Mohd Zaid, Mohd Hafiz; Omar, Nur Alia Sheh

    2016-03-20

    A series of MnO-doped zinc soda lime silica glass systems was prepared by a conventional melt and quenching technique. In this study, the x-ray diffraction analysis was applied to confirm the amorphous nature of the glasses. Fourier transform infrared spectroscopy shows the glass network consists of MnO4, SiO4, and ZnO4 units as basic structural units. The glass samples under field emission scanning electron microscopy observation demonstrated irregularity in shape and size with glassy phase-like structure. The optical absorption studies revealed that the optical bandgap (Eopt) values decrease with an increase of MnO content. Through the results of various measurements, the doping of MnO in the glass matrix had effects on the performance of the glasses and significantly improved the properties of the glass sample as a potential host for phosphor material.

  14. Electron-transport properties of ethyne-bridged diphenyl zinc-porphyrin molecules

    NASA Astrophysics Data System (ADS)

    Duy Nguyen, Huy; Ono, Tomoya

    2015-05-01

    We investigate the electron-transport properties of ethyne-bridged diphenyl zinc-porphyrin molecules suspended between gold (111) electrodes by first-principles calculations within the framework of density functional theory. It is found that the conductance of a molecular junction in which phenyl and porphyrin rings are perpendicular is reduced by three orders of magnitude compared with that of a junction in which the phenyl and porphyrin rings are coplanar. In the coplanar configuration, electrons are transmitted through π states, which extend over the whole molecule. In the perpendicular configuration, the conductance is suppressed because of the reduction of electron hopping between π states of the phenyl ring and σ states of the porphyrin ring.

  15. Electronic and optical properties of zinc-blende GeC by first principles study

    NASA Astrophysics Data System (ADS)

    Zhai, Jinhui; Zhai, Jinguang; Wan, Ajun

    2015-07-01

    The electronic and optical properties of zinc-blende (zb)GeC have been investigated using first principles calculations based on the density functional theory (DFT). The obtained band gap of zb-GeC is 2.30eV by means of Heyd-Scuseria-Ernzerhof (HSE) functional. We have discussed the energy-dependent optical functions including dielectric constants, refractive index, absorption, reflectivity, and energy-loss spectrum in detail. The results reveal that zb-GeC has a higher static dielectric constant compared with that of zb-SiC. The optical functions are mainly associated with the interband transitions from the occupied valence bands (VBs) Ge4p and C2p states to Ge4s, 4p and C2p states of the unoccupied conduction bands (CBs).

  16. REPLY: Reply to 'Comments on "Optoelectronic properties of sprayed transparent and conducting indium doped zinc oxide thin films"'

    NASA Astrophysics Data System (ADS)

    Shinde, S. S.; Shinde, P. S.; Bhosale, C. H.; Rajpure, K. Y.

    2008-11-01

    This communication is a response to the comments made by Tiburcio-Silver and Castañeda on our recently published paper entitled 'Optoelectronic properties of sprayed transparent and conducting indium doped zinc oxide thin films'. Each one of the points questioned is clarified in order to give the respective reasons, and additional information is given that supports the content of our paper.

  17. Chemical composition, morphology and optical properties of zinc sulfide coatings deposited by low-energy electron beam evaporation

    NASA Astrophysics Data System (ADS)

    Ragachev, A. V.; Yarmolenko, M. A.; Rogachev, A. A.; Gorbachev, D. L.; Zhou, Bing

    2014-06-01

    The research determines the features of formation, morphology, chemical composition and optical properties of the coatings deposited by the method, proposed for the first time, of the exposure of mechanical mixture of zinc and sulfur powders to low-energy electron beam evaporation. The findings show that the deposited coatings are characterized by high chemical and structural homogeneity in thickness. The study considers the influence of substrate temperature and thickness of the deposited layer on the morphology and the width of the formed ZnS thin layers band gap. Also was shown the possibility to form ZnS coatings with this method using the mixture of zinc and copper sulfide powders.

  18. The manganese effect on the magnetism and optical properties especially interband transitions of zinc sulphide

    NASA Astrophysics Data System (ADS)

    Aimouch, D. E.; Meskine, S.; Hayn, R.; Zaoui, A.; Boukortt, A.

    2016-10-01

    The electronic, magnetic and optical properties of Mn doped zinc sulphide (ZnS:Mn) were calculated with the FP-LAPW method by using the LSDA and LSDA+U approximations. The latter one is shown to be necessary to account for the strong electron correlation in the Mn 3d shell. With the increase of Mn2+ concentration, the band gap is decreased for the spin-up channel and increased for the spin-down channel. Furthermore, to calculate the correct exchange couplings d-d and sp-d of Mn-doped ZnS, we have applied the Hubbard U parameter on Mn-d states. The influence of this Hubbard U parameter on the optical, electronic and magnetic properties of ZnS:Mn is investigated. We found that U=6 eV gives good results for exchange couplings and optical properties close to the experimental ones. The magnetic coupling between neighboring Mn impurities in ZnS is found to be antiferromagnetic.

  19. 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. PMID:27423301

  20. 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.

  1. Nano/microstructure and optical properties of ZnO particles precipitated from zinc acetylacetonate

    NASA Astrophysics Data System (ADS)

    Petrović, Željka; Ristić, Mira; Musić, Svetozar; Fabián, Martin

    2015-06-01

    The influence of experimental conditions on the nano/microstructure and optical properties of ZnO particles produced by rapid hydrolysis of zinc acetylacetonate, followed by aging of the precipitation system at 160 °C, was investigated. Samples were characterized by XRD, FE scanning electron microscopy (FE-SEM), FT-IR, UV/Vis/NIR and photoluminescence (PL) spectroscopies. XRD patterns of all samples were assigned to the hexagonal ZnO phase (wurtzite-type), as well as the corresponding FT-IR spectra. FE-SEM inspection showed a high dependence of the ZnO nano/microstructure on the chemical composition of the reaction mixture and autoclaving time after the rapid hydrolysis of zinc acetylacetonate. Microstructural differences were noticed between C2H5OH/H2O and H2O media, as well as under the influence of NH4OH addition. Measurements of nanocrystallite sizes showed no significant preferential orientation in the (1 0 0) and (0 0 2) directions relative to the (1 0 1) and (1 1 0) directions. Somewhat smaller crystallite sizes were noticed for ZnO samples synthesized by adding the NH4OH solution. Dissolution/recrystallization of ZnO particles played an important role in the formation of different ZnO nano/microstructures. The band gap values for prepared ZnO samples were calculated on the basis of recorded UV/Vis spectra. PL spectra were recorded for ZnO samples in powder form and their suspensions in pure ethanol. Noticed differences are discussed.

  2. Spectroscopic properties and luminescence behavior of Nd3+ doped zinc alumino bismuth borate glasses

    NASA Astrophysics Data System (ADS)

    Mahamuda, Sk.; Swapna, K.; Srinivasa Rao, A.; Jayasimhadri, M.; Sasikala, T.; Pavani, K.; Rama Moorthy, L.

    2013-09-01

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of neodymium are prepared by using the melt quenching technique to study their physical, absorption and luminescence properties to understand the lasing potentialities of these glasses. From the absorption spectra various spectroscopic parameters and Judd-Ofelt (JO) parameters are evaluated. These JO parameters are used to calculate the transition probability (A), radiative lifetime (τR), and branching ratios (βR) for most of the fluorescent levels of Nd3+. The emission spectra recorded for these glasses gives three prominent transitions 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 for which effective band widths (ΔλP) and stimulated emission cross-sections (σse) are evaluated. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the 4F3/2→4I11/2 transition under investigation has the potential for laser applications. The intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1 mol% and beyond 1 mol% the concentration quenching is observed. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infrared lasers. From the absorption and emission spectral studies it was found that, 1 mol% of Nd3+ ion concentration is optimum for Zinc Alumino Bismuth Borate glasses to generate a strong laser emission at 1060 nm.

  3. Calculated electronic, transport, and related properties of zinc blende boron arsenide (zb-BAs)

    NASA Astrophysics Data System (ADS)

    Nwigboji, Ifeanyi H.; Malozovsky, Yuriy; Franklin, Lashounda; Bagayoko, Diola

    2016-10-01

    We present the results from ab-initio, self-consistent density functional theory (DFT) calculations of electronic, transport, and bulk properties of zinc blende boron arsenide. We utilized the local density approximation potential of Ceperley and Alder, as parameterized by Vosko and his group, the linear combination of Gaussian orbitals formalism, and the Bagayoko, Zhao, and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF), in carrying out our completely self-consistent calculations. With this method, the results of our calculations have the full, physical content of density functional theory (DFT). Our results include electronic energy bands, densities of states, effective masses, and the bulk modulus. Our calculated, indirect band gap of 1.48 eV, from Γ to a conduction band minimum close to X, for the room temperature lattice constant of 4.777 Å, is in an excellent agreement with the experimental value of 1.46 ± 0.02 eV. We thoroughly explain the reasons for the excellent agreement between our findings and corresponding, experimental ones. This work provides a confirmation of the capability of DFT to describe accurately properties of materials, if the computations adhere strictly to the conditions of validity of DFT, as done by the BZW-EF method.

  4. Magnetic properties of conducting polymer doped with manganese zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Poddar, P.; Wilson, J. L.; Srikanth, H.; Morrison, S. A.; Carpenter, E. E.

    2004-10-01

    The magnetic properties of superparamagnetic particles are influenced by the supporting matrix. We have systematically studied the DC magnetic properties of loosely packed manganese-zinc ferrite (Mn0.68Zn0.25Fe2.07O3) nanoparticles synthesized using a reverse micelle technique. The results have been compared with those for particles suspended in paraffin wax and embedded in a polypyrrole matrix. The polypyrrole-doped particles were prepared using an in situ ultraviolet irradiation method and spin-coated into thin films. The loosely packed particles showed no resolvable coercivity even well below the blocking temperature. On the other hand, the same particles in wax showed the opening up of a large coercivity below the blocking temperature. However, both the samples showed characteristic superparamagnetic transition peaks in the temperature-dependent susceptibility nearly at the same temperature. The particles in the polypyrrole matrix showed a remarkable increase in the blocking temperature and large hysteresis at 300 K. The structural characterization of the polymer-doped sample showed clustering of the nanoparticles.

  5. Synthesis and size-dependent properties of zinc-blende semiconductor quantum rods.

    PubMed

    Kan, Shihai; Mokari, Taleb; Rothenberg, Eli; Banin, Uri

    2003-03-01

    Dimensionality and size are two factors that govern the properties of semiconductor nanostructures. In nanocrystals, dimensionality is manifested by the control of shape, which presents a key challenge for synthesis. So far, the growth of rod-shaped nanocrystals using a surfactant-controlled growth mode, has been limited to semiconductors with wurtzite crystal structures, such as CdSe (ref. 3). Here, we report on a general method for the growth of soluble nanorods applied to semiconductors with the zinc-blende cubic lattice structure. InAs quantum rods with controlled lengths and diameters were synthesized using the solution-liquid-solid mechanism with gold nanocrystals as catalysts. This provides an unexpected link between two successful strategies for growing high-quality nanomaterials, the vapour-liquid-solid approach for growing nanowires, and the colloidal approach for synthesizing soluble nanocrystals. The rods exhibit both length- and shape-dependent optical properties, manifested in a red-shift of the bandgap with increased length, and in the observation of polarized emission covering the near-infrared spectral range relevant for telecommunications devices. PMID:12612671

  6. Synthesis and size-dependent properties of zinc-blende semiconductor quantum rods

    NASA Astrophysics Data System (ADS)

    Kan, Shihai; Mokari, Taleb; Rothenberg, Eli; Banin, Uri

    2003-03-01

    Dimensionality and size are two factors that govern the properties of semiconductor nanostructures. In nanocrystals, dimensionality is manifested by the control of shape, which presents a key challenge for synthesis. So far, the growth of rod-shaped nanocrystals using a surfactant-controlled growth mode, has been limited to semiconductors with wurtzite crystal structures, such as CdSe (ref. 3). Here, we report on a general method for the growth of soluble nanorods applied to semiconductors with the zinc-blende cubic lattice structure. InAs quantum rods with controlled lengths and diameters were synthesized using the solution-liquid-solid mechanism with gold nanocrystals as catalysts. This provides an unexpected link between two successful strategies for growing high-quality nanomaterials, the vapour-liquid-solid approach for growing nanowires, and the colloidal approach for synthesizing soluble nanocrystals. The rods exhibit both length- and shape-dependent optical properties, manifested in a red-shift of the bandgap with increased length, and in the observation of polarized emission covering the near-infrared spectral range relevant for telecommunications devices.

  7. Preparation, characterization and optoelectronic properties of nanodiamonds doped zinc oxide nanomaterials by a ball milling technique

    NASA Astrophysics Data System (ADS)

    Ullah, Hameed; Sohail, Muhammad; Malik, Uzma; Ali, Naveed; Bangash, Masroor Ahmad; Nawaz, Mohsan

    2016-07-01

    Zinc oxide (ZnO) is one of the very important metal oxides (MOs) for applications in optoelectronic devices which work in the blue and UV regions. However, to meet the challenges of obtaining ZnO nanomaterials suitable for practical applications, various modifications in physico-chemical properties are highly desirable. One of the ways adopted for altering the properties is to synthesize composite(s) of ZnO with various reinforcements. Here we report on the tuning of optoelectronic properties of ZnO upon doping by nanodiamonds (NDs) using the ball milling technique. A varying weight percent (wt.%) of NDs were ball milled for 2 h with ZnO nanoparticles prepared by a simple precipitation method. The effects of different parameters, the calcination temperature of ZnO, wt.% of NDs and mechanical milling upon the optoelectronic properties of the resulting ZnO-NDs nanocomposites have been investigated. The ZnO-NDs nanocomposites were characterized by IR spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The UV-vis spectroscopy revealed the alteration in the bandgap energy (Eg ) of ZnO as a function of the calcination temperature of ZnO, changing the concentration of NDs, and mechanical milling of the resulting nanocomposites. The photoluminescence (PL) spectroscopy showed a decrease in the deep level emission (DLE) peaks and an increase in near-band-edge transition peaks as a result of the increasing concentration of NDs. The decrease in DLE and increase in band to band transition peaks were due to the strong interaction between the NDs and the Zn+; consequently, the Zn+ concentration decreased on the interstitial sites.

  8. Preparation, characterization and optoelectronic properties of nanodiamonds doped zinc oxide nanomaterials by a ball milling technique

    NASA Astrophysics Data System (ADS)

    Ullah, Hameed; Sohail, Muhammad; Malik, Uzma; Ali, Naveed; Bangash, Masroor Ahmad; Nawaz, Mohsan

    2016-07-01

    Zinc oxide (ZnO) is one of the very important metal oxides (MOs) for applications in optoelectronic devices which work in the blue and UV regions. However, to meet the challenges of obtaining ZnO nanomaterials suitable for practical applications, various modifications in physico-chemical properties are highly desirable. One of the ways adopted for altering the properties is to synthesize composite(s) of ZnO with various reinforcements. Here we report on the tuning of optoelectronic properties of ZnO upon doping by nanodiamonds (NDs) using the ball milling technique. A varying weight percent (wt.%) of NDs were ball milled for 2 h with ZnO nanoparticles prepared by a simple precipitation method. The effects of different parameters, the calcination temperature of ZnO, wt.% of NDs and mechanical milling upon the optoelectronic properties of the resulting ZnO–NDs nanocomposites have been investigated. The ZnO–NDs nanocomposites were characterized by IR spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The UV-vis spectroscopy revealed the alteration in the bandgap energy (Eg ) of ZnO as a function of the calcination temperature of ZnO, changing the concentration of NDs, and mechanical milling of the resulting nanocomposites. The photoluminescence (PL) spectroscopy showed a decrease in the deep level emission (DLE) peaks and an increase in near-band-edge transition peaks as a result of the increasing concentration of NDs. The decrease in DLE and increase in band to band transition peaks were due to the strong interaction between the NDs and the Zn+; consequently, the Zn+ concentration decreased on the interstitial sites.

  9. Effect of zinc oxide amounts on the properties and antibacterial activities of zeolite/zinc oxide nanocomposite.

    PubMed

    Alswat, Abdullah A; Ahmad, Mansor Bin; Saleh, Tawfik A; Hussein, Mohd Zobir Bin; Ibrahim, Nor Azowa

    2016-11-01

    Nanocomposites of zinc oxide loaded on a zeolite (Zeolite/ZnO NCs) were prepared using co-precipitation method. The ratio effect of ZnO wt.% to the Zeolite on the antibacterial activities was investigated. Various techniques were used for the nanocomposite characterization, including UV-vis, FTIR, XRD, EDX, FESEM and TEM. XRD patterns showed that ZnO peak intensity increased while the intensities of Zeolite peaks decreased. TEM images indicated a good distribution of ZnO-NPs onto the Zeolite framework and the cubic structure of the zeolite was maintained. The average particle size of ZnO-nanoparticles loaded on the surface of the Zeolite was in the range of 1-10nm. Moreover, Zeolite/ZnO NCs showed noticeable antibacterial activities against the tested bacteria; Gram- positive and Gram- negative bacteria, under normal light. The efficiency of the antibacterial increased with increasing the wt.% from 3 to 8 of ZnO NPs, and it reached 87% against Escherichia coli E266.

  10. Comparison study of electrochemical properties of porous zinc oxide/N-doped carbon and pristine zinc oxide polyhedrons

    NASA Astrophysics Data System (ADS)

    Zhou, Zhenfang; Zhang, Kun; Liu, Jinghao; Peng, Hongrui; Li, Guicun

    2015-07-01

    An in-situ calcination strategy has been developed for the synthesis of porous zinc oxide/N-doped carbon (ZnO/NC) polyhedrons, in which zeolitic imidazolate framework-8 (ZIF-8) serves as the precursor. The ZnO/NC polyhedrons with a hierarchical architecture possess a high specific surface area of 390.7 m2 g-1, high nitrogen content (19.99 at%), and robust pore structures. The porous N-doped carbon frameworks can not only increase the electronic conductivity of ZnO, but also provide interior space for the fast diffusion of Li+ ions and accommodate the volume variations during the charge and discharge cycles. When evaluated for lithium storage capacity, the hierarchical ZnO/NC polyhedrons exhibit high reversible discharge capacity (834.3 mAh g-1 at the initial low rate of 0.5C, 1C = 978 mA g-1), superior rate performance (399.2 mAh g-1 at 5C and 253.5 mAh g-1 at 10C), and excellent cycling stability (677.9 mAh g-1 at 1C after 400 cycles). The reasons are explored in terms of the well-confined primary nanocrystals (5 nm), and the finely constructed interconnected pores of the N-doped carbon networks, which facilitate the fast and effective transfer of Li+ ions and electrons, and accommodate the large volume expansions.

  11. Effect of zinc oxide amounts on the properties and antibacterial activities of zeolite/zinc oxide nanocomposite.

    PubMed

    Alswat, Abdullah A; Ahmad, Mansor Bin; Saleh, Tawfik A; Hussein, Mohd Zobir Bin; Ibrahim, Nor Azowa

    2016-11-01

    Nanocomposites of zinc oxide loaded on a zeolite (Zeolite/ZnO NCs) were prepared using co-precipitation method. The ratio effect of ZnO wt.% to the Zeolite on the antibacterial activities was investigated. Various techniques were used for the nanocomposite characterization, including UV-vis, FTIR, XRD, EDX, FESEM and TEM. XRD patterns showed that ZnO peak intensity increased while the intensities of Zeolite peaks decreased. TEM images indicated a good distribution of ZnO-NPs onto the Zeolite framework and the cubic structure of the zeolite was maintained. The average particle size of ZnO-nanoparticles loaded on the surface of the Zeolite was in the range of 1-10nm. Moreover, Zeolite/ZnO NCs showed noticeable antibacterial activities against the tested bacteria; Gram- positive and Gram- negative bacteria, under normal light. The efficiency of the antibacterial increased with increasing the wt.% from 3 to 8 of ZnO NPs, and it reached 87% against Escherichia coli E266. PMID:27524047

  12. Low-power scan driver embedded with level shifter using depletion-mode amorphous indium-gallium-zinc-oxide thin-film transistors for high-resolution flat-panel displays

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hee; Kwon, Oh-Kyong

    2014-01-01

    A low-power scan driver embedded with a level shifter using depletion-mode amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) is proposed for high-resolution flat-panel displays (FPDs). In order to achieve low power consumption, the scan driver uses clock signals with a reduced voltage swing. Furthermore, the level shifter is implemented without using a diode-connected TFT. This scan driver is simulated at an output voltage swing of 30 V and an operating frequency (fop) of 153.6 kHz, which satisfy the driving conditions for 10-in. wide quadruple extended graphics array (WQXGA, 1600 × 2560) FPDs with a frame frequency of 60 Hz. The simulation results of the proposed scan driver demonstrate the successful operation even at a threshold voltage shift (ΔVth) of -2.0 V. The power consumption of the proposed scan driver per ten stages is 0.41 mW, which is 80.75% less than that reported in a previous work.

  13. Low-frequency noise properties in Pt-indium gallium zinc oxide Schottky diodes

    SciTech Connect

    Zhang, Jiawei; Zhang, Linqing; Ma, Xiaochen; Wilson, Joshua; Jin, Jidong; Du, Lulu; Xin, Qian; Song, Aimin

    2015-08-31

    The low-frequency noise properties of Pt-indium gallium zinc oxide (IGZO) Schottky diodes at different forward biases are investigated. The IGZO layer and Pt contact were deposited by RF sputtering at room temperature. The diode showed an ideality factor of 1.2 and a barrier height of 0.94 eV. The current noise spectral density exhibited 1/f behavior at low frequencies. The analysis of the current dependency of the noise spectral density revealed that for the as-deposited diode, the noise followed Luo's mobility and diffusivity fluctuation model in the thermionic-emission-limited region and Hooge's empirical theory in the series-resistance-limited region. A low Hooge's constant of 1.4 × 10{sup −9} was found in the space-charge region. In the series-resistance-limited region, the Hooge's constant was 2.2 × 10{sup −5}. After annealing, the diode showed degradation in the electrical performance. The interface-trap-induced noise dominated the noise spectrum. By using the random walk model, the interface-trap density was obtained to be 3.6 × 10{sup 15 }eV{sup −1 }cm{sup −2}. This work provides a quantitative approach to analyze the properties of Pt-IGZO interfacial layers. These low noise properties are a prerequisite to the use of IGZO Schottky diodes in switch elements in memory devices, photosensors, and mixer diodes.

  14. First-principles study of the electronic properties of wurtzite, zinc-blende, and twinned InP nanowires

    SciTech Connect

    Li, Dengfeng; Wang, Zhiguo; Gao, Fei

    2010-12-17

    The electronic properties of zinc blende, wurtzite, and rotationally twinned InP nanowires were studied using first-principles calculations. The results show that all the simulated nanowires exhibit a semiconducting character, and the band gap decreases with increasing the nanowire size. The band gap difference between the zinc blende, wurtzite, and twinned InP nanowires and a bulk InP can be described by several formulas proportional to the diameter of nanowires. The valence band maximum (VBM) and conduction band minimum (CBM) originate mainly from the p-orbitals of the P atoms and s-orbitals of the In atoms at the core regions of the nanowires, respectively. The hexagonal (2H) stacking inside the cubic (3C) stacking has no effect on the electronic properties of thin InP nanowires.

  15. Effects of Clear and Amber Cullet on Physical and Mechanical Properties of Glass-Ceramics Containing Zinc Hydrometallurgy Waste

    NASA Astrophysics Data System (ADS)

    Hanpongpun, Wilasinee; Jiemsirilers, Sirithan; Thavorniti, Parjaree

    The effect of glass cullet on physical and mechanical properties of glass-ceramics developed from zinc hydrometallurgy waste and glass cullet was investigated. The glass-ceramics were prepared by mixing zinc hydrometallurgy waste with glass cullet through vitrification process. Two difference types of glass cullet (clear and amber cullet) were used. The parent glasses were ground and pressed into bars and sintered at low temperature (850°C) for 2 hours. The obtained glass-ceramics had low porosity. The glass-ceramics with clear cullet exhibited higher density and strength, comparing with the glass-ceramics with amber cullet. The type and the amount of the glass cullet present in the glass-ceramics have strong effect on their properties.

  16. Temperature Effect on Structural and Electronic Properties of Zinc Oxide Nanowires Synthesized by Carbothermal Evaporation Method

    NASA Astrophysics Data System (ADS)

    Orvatinia, Mohammad; Imani, Roghayeh

    2012-10-01

    Zinc Oxide (ZnO) nanowires were synthesized on the Si substrates by carbothermal evaporation of ZnO + C at elevated temperatures. The syntheses were carried out at different temperatures from 750°C to 950°C. Characterizations of layers were performed to study the effect of synthesis temperature on morphology, crystal structure and electrical behavior of fabricated nanowires. The physical characterization was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDAX) methods. SEM micrograph of layers revealed that the samples grown at the lower temperatures have better quality. However, below 800°C the growth of nanowires was stopped. So the 800°C was concluded to be the optimum temperature for growth of high quality nanowires by proposed system. By recording the conductivity variations as a function of inverse temperature, 1/T, the semiconductor property of the samples was verified. It is demonstrated that two distinct factors affect the electrical conductivity of layers, which are due to the bulk and grain boundary. We experimentally proved that the activation energy corresponding to grain boundary is higher than that of the bulk. As another result we have established for the first time that by increasing synthesis temperatures, both activation energies shift to higher values.

  17. Epitaxial aluminum-doped zinc oxide thin films on sapphire. 2: Defect equilibria and electrical properties

    SciTech Connect

    Srikant, V.; Sergo, V.; Clarke, D.R.

    1995-07-01

    The electrical transport properties of epitaxial ZnO films grown on different orientations of sapphire substrates have been measured as a function of partial pressure of oxygen. After equilibration, the carrier concentration is found to change from a p{sub O{sub 2}}{sup {minus}1/4} to a p{sub O{sub 2}}{sup {minus}3/8} dependence with increasing oxygen partial pressure. The partial pressure dependence is shown to be consistent with zinc vacancies being the rate-controlling diffusive species. In addition, the carrier concentration in ZnO films grown on A-, C-, and M-plane sapphire are the same but that of R-plane sapphire is systematically lower. Electron Hall mobility measurements as a function of carrier concentration for all the substrate orientations exhibit a transition from ``single-crystal`` behavior at high carrier concentrations to ``polycrystalline`` behavior at low carrier concentrations. This behavior is attributed to the effective height of potential barriers formed at the low-angle grain boundaries in the epitaxial ZnO films. The trap density at the grain boundaries is deduced to be {approximately}7 {times} 10{sup 12}/cm{sup 2}. The electron mobility, at constant carrier concentration, varies with the substrate orientation on which the ZnO films were grown. The difference is attributed to the difference in dislocation density in the films produced as a result of lattice mismatch with the different sapphire orientations.

  18. Control of zinc oxide nanowire array properties with electron-beam lithography templating for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Nicaise, Samuel M.; Cheng, Jayce J.; Kiani, Amirreza; Gradečak, Silvija; Berggren, Karl K.

    2015-02-01

    Hydrothermally synthesized zinc oxide nanowire arrays have been used as nanostructured acceptors in emerging photovoltaic (PV) devices. The nanoscale dimensions of such arrays allow for enhanced charge extraction from PV active layers, but the device performance critically depends on the nanowire array pitch and alignment. In this study, we templated hydrothermally-grown ZnO nanowire arrays via high-resolution electron-beam-lithography defined masks, achieving the dual requirements of high-resolution patterning at a pitch of several hundred nanometers, while maintaining hole sizes small enough to control nanowire array morphology. We investigated several process conditions, including the effect of annealing sputtered and spincoated ZnO seed layers on nanowire growth, to optimize array property metrics—branching from individual template holes and off-normal alignment. We found that decreasing template hole size decreased branching prevalence but also reduced alignment. Annealing seed layers typically improved alignment, and sputtered seed layers yielded nanowire arrays superior to spincoated seed layers. We show that these effects arose from variation in the size of the template holes relative to the ZnO grain size in the seed layer. The quantitative control of branching and alignment of the nanowire array that is achieved in this study will open new paths toward engineering more efficient electrodes to increase photocurrent in nanostructured PVs. This control is also applicable to inorganic nanowire growth in general, nanomechanical generators, nanowire transistors, and surface-energy engineering.

  19. Electrical and gas sensing properties of self-aligned copper-doped zinc oxide nanoparticles

    SciTech Connect

    Sonawane, Yogesh S.; Kanade, K.G.; Kale, B.B. Aiyer, R.C.

    2008-10-02

    Electrical and gas sensing properties of nanocrystalline ZnO:Cu, having Cu X wt% (X = 0.0, 0.5, 1.0, and 1.5) in ZnO, in the form of pellet were investigated. Copper chloride and zinc acetate were used as precursors along with oxalic acid as a precipitating reagent in methanol. Material characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and inductive coupled plasma with optical emission spectrometry (ICP-OES). FE-SEM showed the self-aligned Cu-doped ZnO nano-clusters with particles in the range of 40-45 nm. The doping of 0.5% of copper changes the electrical conductivity by an order of magnitude whereas the temperature coefficient of resistance (TCR) reduces with increase in copper wt% in ZnO. The material has shown an excellent sensitivity for the H{sub 2}, LPG and CO gases with limited temperature selectivity through the optimized operating temperature of 130, 190 and 220 deg. C for H{sub 2}, LPG and CO gases, respectively at 625 ppm gas concentration. The %SF was observed to be 1460 for H{sub 2} at 1% Cu doping whereas the 0.5% Cu doping offered %SF of 950 and 520 for CO and LPG, respectively. The response and recovery time was found to be 6 to 8 s and 16 s, respectively.

  20. Structural and luminescence properties of Sm3+ ions in zinc fluorophosphate glasses

    NASA Astrophysics Data System (ADS)

    Lim, Ki-Soo; Vijaya, N.; Kesavulu, C. R.; Jayasankar, C. K.

    2013-06-01

    Sm3+-doped zinc fluorophosphate (PKAZLFSm) glasses have been prepared by conventional melt quenching technique and are characterized through thermal, Raman, absorption, emission and decay rate analysis. The Judd-Ofelt (JO) theory has been used to derive the spectroscopic properties of Sm3+:PKAZLFSm glasses. The decay rates for the 4G5/2 level of Sm3+ ions have been measured and are found to be single exponential at lower concentration (⩽0.1 mol% Sm2O3) and turns into non-exponential at higher concentrations (⩾0.5 mol% Sm2O3) due to energy transfer through cross-relaxation. The experimental lifetimes for 4G5/2 level of Sm3+ ions are found to decrease from 3.2 to 0.5 ms when the concentration increased from 0.01 to 4.0 mol% Sm2O3 due to energy transfer among Sm3+ ions. In order to know the nature of the energy transfer mechanism, the non-exponential decay rates are well fitted to Inokuti-Hirayama model for S = 6, indicating that the energy transfer process is of dipole-dipole type. The results obtained for the 4G5/2 → 6H7/2 transition indicate that the Sm3+:PKAZLFSm10 glass can be very much useful for the development of visible lasers in the reddish orange spectral region.

  1. Enhanced optical properties due to indium incorporation in zinc oxide nanowires

    NASA Astrophysics Data System (ADS)

    Farid, S.; Mukherjee, S.; Sarkar, K.; Mazouchi, M.; Stroscio, M. A.; Dutta, M.

    2016-01-01

    Indium-doped zinc oxide nanowires grown by vapor-liquid-solid technique with 1.6 at. % indium content show intense room temperature photoluminescence (PL) that is red shifted to 20 meV from band edge. We report on a combination of nanowires and nanobelts-like structures with enhanced optical properties after indium doping. The near band edge emission shift gives an estimate for the carrier density as high as 5.5 × 1019 cm-3 for doped nanowires according to Mott's critical density theory. Quenching of the visible green peak is seen for doped nanostructures indicating lesser oxygen vacancies and improved quality. PL and transmission electron microscopy measurements confirm indium doping into the ZnO lattice, whereas temperature dependent PL data give an estimation of the donor and acceptor binding energies that agrees well with indium doped nanowires. This provides a non-destructive technique to estimate doping for 1D structures as compared to the traditional FET approach. Furthermore, these indium doped nanowires can be a potential candidate for transparent conducting oxides applications and spintronic devices with controlled growth mechanism.

  2. Experimental and theoretical study on field emission properties of zinc oxide nanoparticles decorated carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Xin; Zhou, Wei-Man; Liu, Wei-Hua; Wang, Xiao-Li

    2015-05-01

    Field emission properties of zinc oxide (ZnO) nanoparticles (NPs) decorated carbon nanotubes (CNTs) are investigated experimentally and theoretically. CNTs are in situ decorated with ZnO NPs during the growth process by chemical vapor deposition using a carbon source from the iron phthalocyanine pyrolysis. The experimental field emission test shows that the ZnO NP decoration significantly improves the emission current from 50 μA to 275 μA at 550 V and the reduced threshold voltage from 450 V to 350 V. The field emission mechanism of ZnO NPs on CNTs is theoretically studied by the density functional theory (DFT) combined with the Penn-Plummer method. The ZnO NPs reconstruct the ZnO-CNT structure and pull down the surface barrier of the entire emitter system to 0.49 eV so as to reduce the threshold electric field. The simulation results suggest that the presence of ZnO NPs would increase the LDOS near the Fermi level and increase the emission current. The calculation results are consistent with the experiment results. Project supported by the National Natural Science Foundation of China (Grant Nos. 91123018, 61172040, and 61172041) and the Natural Science Foundation of Shaanxi Province, China (Grant No. 2014JM7277).

  3. Ionothermal synthesis, properties and vibrational spectra of zinc (II) complex with nicotinamide.

    PubMed

    Li, Chunyan; Cui, Fenghua; Zhang, Heng; Xuan, Xiaopeng

    2015-01-01

    The zinc (II) complex with nicotinamide, (C₆H₁₁N₂)[ZnBr₃(C₆H₆N₂O)], was prepared under ionothermal condition by using the ionic liquid 1-ethyl-3-methylimidazolium bromide ([EMIM]Br) as a solvent. At the same time, [EMIM]Br also functions as a structure-directing agent, leading to a framework structure different from those obtained by the conventional methods. Single-crystal X-ray analysis revealed that the coordinated compound crystallizes in monoclinic space group P2(1)/c, and the Zn (II) ion is four-coordinated by one pyridine ring N atom and three bromide anions in a slightly distorted tetrahedron arrangement. The [EMIM](+) cations acting as the extra framework charge balancing species occupy the channels of this asymmetric unit. In the crystal structure, intermolecular NH⋯Br and NH⋯O hydrogen bonds link the molecules to form a supramolecular structure. In addition, this compound was further characterized by FT-IR and Raman spectroscopic techniques, and the observed important bands were assigned. Thermogravimetric analysis (TG), Differential Scanning Calorimetry (DSC) and fluorescent properties of solid samples were also studied at room temperature. PMID:25025308

  4. Structural, Electrical and Optical Properties of Gallium Doped Zinc Oxide Thin Films Prepared by Electron Beam Evaporation Technique

    SciTech Connect

    Nagarani, S.; Sanjeeviraja, C.

    2011-07-15

    High quality gallium doped zinc oxide (GZO) films are prepared by electron beam evaporation technique. The effect of substrate temperature on structural, electrical and optical properties was studied in detail. The prepared films are polycrystalline in nature with c-axis perpendicular to the substrate. The resistivity of the film decreases and the optical transparency increases as the substrate temperature increases from room temperature to 150 deg. C. The film produce the optical band gap of 3.47 eV.

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

    SciTech Connect

    Sai, Ranajit; Endo, Yasushi; Shimada, Yutaka; Yamaguchi, Masahiro; Shivashankar, S. A.

    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 high 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.

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

    NASA Astrophysics Data System (ADS)

    Sai, Ranajit; Endo, Yasushi; Shimada, Yutaka; Yamaguchi, Masahiro; Shivashankar, S. A.

    2015-05-01

    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 (fFMR) 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 high 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 fFMR 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.

  7. Electrochemical properties of electrospun poly(5-cyanoindole) submicron-fibrous electrode for zinc/polymer secondary battery

    NASA Astrophysics Data System (ADS)

    Cai, Zhijiang; Guo, Jie; Yang, Haizheng; Xu, Yi

    2015-04-01

    This study aims to develop an aqueous zinc/electrospun poly(5-cyanoindole) fibers secondary battery system. Zn foil and ZnCl2 are used as anode active materials and the electrolytic solution, respectively. Poly(5-cyanoindole) synthesized by chemical oxidation is electrospun into fibers and used as cathode active materials. FTIR and NMR test are carried out to investigate the chemical structure of poly(5-cyanoindole). Surface properties of electrospun poly(5-cyanoindole) fibers are studied by SEM, TEM, and BET. The performance of zinc/electrospun poly(5-cyanoindole) fibers battery system is evaluated in term of electrical conductivity, cyclic voltammogram, electrochemical impedance spectroscopy, discharge capacity and durability test. The cell achieves 2.0 V electromotive force with about 107-61 Ah Kg-1 discharge capacity at 0.2C-10C rate. At 800th cycle, the discharge capacity remains 80-57 Ah Kg-1 at 0.2C-2C rate, which is about 75-63% of the maximum discharge capacity. These results indicate that the cell has very excellent cyclic properties as well as fast charge/discharge properties. Electrospun poly(5-cyanoindole) fibers have been proved to be a better candidate than polyindole powder as cathode material in zinc/polymer battery.

  8. Zinc and zinc transporters in prostate carcinogenesis

    PubMed Central

    Kolenko, Vladimir; Teper, Ervin; Kutikov, Alexander; Uzzo, Robert

    2013-01-01

    The healthy human prostate accumulates the highest level of zinc of any soft tissue in the body. This unique property is retained in BPH, but is lost in prostatic malignancy, which implicates changes in zinc and its transporters in carcinogenesis. Indeed, zinc concentrations diminish early in the course of prostate carcinogenesis, preceding histopathological changes, and continue to decline during progression toward castration-resistant disease. Numerous studies suggest that increased zinc intake might protect against progression of prostatic malignancy. Despite increased dietary intake, zinc accumulation might be limited by the diminished expression of zinc uptake transporters, resulting in decreased intratumoural zinc levels. This finding can explain the conflicting results of various epidemiological studies evaluating the role of zinc supplementation on primary and secondary prostate cancer prevention. Overall, more research into the mechanisms of zinc homeostasis are needed to fully understand its impact on prostate carcinogenesis. Only then can the potential of zinc and zinc transport proteins be harnessed in the diagnosis and treatment of men with prostate cancer. PMID:23478540

  9. Effect of zinc sulphate on gelling properties of phosphorylated protein isolate from yellow stripe trevally.

    PubMed

    Arfat, Yasir Ali; Benjakul, Soottawat

    2013-12-01

    Impacts of zinc sulphate (ZnSO4) (0-140 μmol/kg) on gel properties of yellow stripe trevally surimi added with sodium tripolyphosphate (STPP) (0.25% and 0.5%, w/w) and protein isolate phosphorylated with STPP at 0.25% and 0.5% (w/w) were studied. Gels from surimi added with 60 μmol ZnSO4/kg in the absence and presence of 0.5% STPP had the increases in breaking force and deformation by 20.9% and 33.3%, and 11.6% and 18.6%, respectively, compared with the control surimi gel (without additives). Gel of protein isolate phosphorylated with 0.5% STPP containing 100 μmol ZnSO4/kg had the increases in breaking force and deformation by 14.87% and 5.6%, respectively, compared with the gel from non-phosphorylated protein isolate at the same ZnSO4 level, suggesting that the phosphorylated protein isolate was more crosslinked by Zn(2+). The addition of ZnSO4 at the suitable level lowered the expressible moisture content, but increased whiteness of surimi or protein isolate gels (P<0.05). Non-covalent bonds, more likely salt bridge and ionic interactions, played a major role in cross-linking of proteins in both surimi and protein isolate added with ZnSO4, regardless of phosphates incorporated. Microstructure study revealed that a gel having highly interconnected and denser network with smaller voids was formed when protein isolate phosphorylated with 0.5% STPP was added with ZnSO4 at a level of 100 μmol/kg. Thus, gel with improved properties could be obtained from protein isolate from yellow stripe trevally phosphorylated with STPP in conjunction with addition of ZnSO4 at an appropriate level.

  10. Effect of zinc sulphate on gelling properties of phosphorylated protein isolate from yellow stripe trevally.

    PubMed

    Arfat, Yasir Ali; Benjakul, Soottawat

    2013-12-01

    Impacts of zinc sulphate (ZnSO4) (0-140 μmol/kg) on gel properties of yellow stripe trevally surimi added with sodium tripolyphosphate (STPP) (0.25% and 0.5%, w/w) and protein isolate phosphorylated with STPP at 0.25% and 0.5% (w/w) were studied. Gels from surimi added with 60 μmol ZnSO4/kg in the absence and presence of 0.5% STPP had the increases in breaking force and deformation by 20.9% and 33.3%, and 11.6% and 18.6%, respectively, compared with the control surimi gel (without additives). Gel of protein isolate phosphorylated with 0.5% STPP containing 100 μmol ZnSO4/kg had the increases in breaking force and deformation by 14.87% and 5.6%, respectively, compared with the gel from non-phosphorylated protein isolate at the same ZnSO4 level, suggesting that the phosphorylated protein isolate was more crosslinked by Zn(2+). The addition of ZnSO4 at the suitable level lowered the expressible moisture content, but increased whiteness of surimi or protein isolate gels (P<0.05). Non-covalent bonds, more likely salt bridge and ionic interactions, played a major role in cross-linking of proteins in both surimi and protein isolate added with ZnSO4, regardless of phosphates incorporated. Microstructure study revealed that a gel having highly interconnected and denser network with smaller voids was formed when protein isolate phosphorylated with 0.5% STPP was added with ZnSO4 at a level of 100 μmol/kg. Thus, gel with improved properties could be obtained from protein isolate from yellow stripe trevally phosphorylated with STPP in conjunction with addition of ZnSO4 at an appropriate level. PMID:23871033

  11. Effect of thermal implying during ageing process of nanorods growth on the properties of zinc oxide nanorod arrays

    NASA Astrophysics Data System (ADS)

    Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Abdullah, M. A. R.; Sin, M. D.; Rusop, M.

    2016-07-01

    Undoped and Sn-doped Zinc oxide (ZnO) nanostructures have been fabricated using a simple sol-gel immersion method at 95°C of growth temperature. Thermal sourced by hot plate stirrer was supplied to the solution during ageing process of nanorods growth. The results showed significant decrement in the quality of layer produced after the immersion process where the conductivity and porosity of the samples reduced significantly due to the thermal appliance. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

  12. Surface morphology and nanomechanical properties of tribological antiwear films derived from zinc dialkyl dithiophosphate compounds

    NASA Astrophysics Data System (ADS)

    Aktary, Mirwais

    The protection of mechanical equipment from wear is of significant economic interest. It has been estimated that up to half of a percent of the gross domestic product of industrialized countries goes to replacing mechanical components that have lost compliance due to wear. Antiwear additives are key ingredients in lubrication oils that assist in protecting components from wear during high loads. These agents form sacrificial films on metal parts that limit the adhesion between the contacting surfaces and reduce the wear rate considerably. One of the most common classes of compounds employed as an antiwear agent is zinc dialkyldithiophosphates (ZDDP). This work will explore the formation, structure, and mechanical properties of ZDDP derived antiwear films on the nanoscale. These studies are important because the macroscopic performance of antiwear coatings is dictated by their nanoscale surface properties. As a first study, scanning force microscopy (SFM) is employed to track the formation of films formed from the thermooxidative decomposition of ZDDP on gold substrates. The SFM analysis is correlated with infrared spectroscopy to relate surface structure to chemical composition. The morphology and mechanical strength of ZDDP tribofilms formed at the interface of sliding stainless steel contacts is also investigated. The tribofilms evolve morphologically with contact time and are characterized by distinct segregated islands at low times that transforms to a full film at longer times. The nanomechanical properties of the tribofilms are evaluated by nanoindentation analysis. It is found that the films are mechanically softer than the underlying steel substrate. SFM and nanoindentation analyses reveal that calcium sulphonate detergents promote the formation of ZDDP tribofilms and impart to them greater mechanical stability. By contrast succinimide dispersants reduce the capacity of ZDDP to form effective antiwear films. The first application of SFM and nanoindentation

  13. To study the flow property of seven commercially available zinc oxide eugenol impression material at various time intervals after mixing.

    PubMed

    Katna, Vishal; Suresh, S; Vivek, Sharma; Meenakshi, Khandelwal; Ankita, Gaur

    2014-12-01

    Aims and objective of the study was to evaluate the flow property of seven commercially available zinc oxide eugenol impression materials at various time intervals, after mixing 49 samples (seven groups) were fabricated for flow property of the material. The sample were fabricated as equal length of base and accelerator paste of the test materials was taken on the glass slab and mixed with a rigid stainless steel spatula as per manufacturers recommendation till the homogenous mix was obtained. The mix material was loaded in glass syringe and 0.5 ml material was injected on a cellophane sheet placed on marked glass plate. A cellophane sheet and glass plate 70 and 500 g weight was carefully placed on freshly dispensed zinc oxide eugenol impression paste sequentially. The diameter of the mix was noted after 30 s and 1 min of load application and also after the final set of material. The diameter gives the flow of material. The samples were stored at the room temperature. The data of the flow property was analyzed with analysis of variance, Post hoc test and t test. The flow of the zinc oxide eugenol impression paste after 30 s, 1 min and final set of load application for Group A to Group G was noted. Maximum flow was seen for Group G zinc oxide eugenol impression material followed by Group F, D, E, B, C and A in descending order respectively after 30 s, where as the flow property changed after 1 min in the sequence of maximum for Group G followed by Group E, D, B, A, C, and F. Lastly after final set of the impression material the flow maximum for Group G followed by Group E, D, C, F, A and B in descending order. Based on statistical analysis of the results and within in the limitations of this in-vitro study, the following conclusions were drawn that; the flow of zinc oxide eugenol impression material after 30 s, 1 min and that after the final set was maximum for P.S.P. (Group G) and the flow for PYREX (Group A) was minimum.

  14. Enhanced efficacy and sensory properties of an anti-dandruff shampoo containing zinc pyrithione and climbazole.

    PubMed

    Turner, G A; Matheson, J R; Li, G-Z; Fei, X-Q; Zhu, D; Baines, F L

    2013-02-01

    Dandruff is a common complaint and is suffered by as much as half of the population at some time post puberty. The condition is characterized by the presence of flakes on the scalp and in the hair, and is often accompanied by itch. The most common treatment for dandruff is the use of shampoo formulations that contain fungistatic agents such as zinc pyrithione (ZPT) and octopirox. Whilst most antidandruff shampoos are effective in resolving the symptoms of dandruff these shampoos can often result in hair condition that is less than acceptable to consumers which can lead to a tendency for them to revert to use of a non-antidandruff shampoo. This can result in a rapid return of dandruff symptoms. The aim of this investigation was to study the impact of using a combination of antidandruff actives and silicones on the resolution of dandruff and to deliver superior sensory properties to the hair. We have demonstrated that shampoo containing the dual active system of ZPT/Climbazole deposits both active agents onto a model skin surface (VitroSkin) and reduces Malassezia furfur regrowth in vitro. Clinical evaluation of the dual active shampoo demonstrated superior efficacy and retained superiority during a regression phase where all subjects reverted to using a non-antidandruff shampoo. We have also demonstrated that it is possible to deposit silicone materials from antidandruff shampoo uniformly over both virgin and damaged hair fibres that results in smoother hair fibres (as evidenced by reduced dry friction). This combination of antidandruff agents and conditioning silicones delivered from a shampoo provides subjects with superior antidandruff efficacy and desired end sensory benefits ensuring compliance and longer term dandruff removal.

  15. Enhanced efficacy and sensory properties of an anti-dandruff shampoo containing zinc pyrithione and climbazole.

    PubMed

    Turner, G A; Matheson, J R; Li, G-Z; Fei, X-Q; Zhu, D; Baines, F L

    2013-02-01

    Dandruff is a common complaint and is suffered by as much as half of the population at some time post puberty. The condition is characterized by the presence of flakes on the scalp and in the hair, and is often accompanied by itch. The most common treatment for dandruff is the use of shampoo formulations that contain fungistatic agents such as zinc pyrithione (ZPT) and octopirox. Whilst most antidandruff shampoos are effective in resolving the symptoms of dandruff these shampoos can often result in hair condition that is less than acceptable to consumers which can lead to a tendency for them to revert to use of a non-antidandruff shampoo. This can result in a rapid return of dandruff symptoms. The aim of this investigation was to study the impact of using a combination of antidandruff actives and silicones on the resolution of dandruff and to deliver superior sensory properties to the hair. We have demonstrated that shampoo containing the dual active system of ZPT/Climbazole deposits both active agents onto a model skin surface (VitroSkin) and reduces Malassezia furfur regrowth in vitro. Clinical evaluation of the dual active shampoo demonstrated superior efficacy and retained superiority during a regression phase where all subjects reverted to using a non-antidandruff shampoo. We have also demonstrated that it is possible to deposit silicone materials from antidandruff shampoo uniformly over both virgin and damaged hair fibres that results in smoother hair fibres (as evidenced by reduced dry friction). This combination of antidandruff agents and conditioning silicones delivered from a shampoo provides subjects with superior antidandruff efficacy and desired end sensory benefits ensuring compliance and longer term dandruff removal. PMID:22970742

  16. Depletion effect of oxide semiconductor analyzed by Hall effects.

    PubMed

    Oh, Teresa

    2014-12-01

    This letter discusses the tunneling behavior of amorphous indium-gallium-zinc-oxide (a-IGZO) analyzed through the observation of its Hall effects. The properties of the a-IGZO changed from those of a majority carrier to those of a minority carrier after the annealing process as a result of the electron-hole recombination due to the thermal activation energy and the formation of a depletion layer with a high-potential Schottky barrier. Therefore, the diffusion current of these minority charge carriers caused ambipolar transfer characteristics, a tunneling behavior, in the metal-oxide semiconductor (MOS) transistor. PMID:25971008

  17. Electrical and Optical Properties of Hydrogen Doped Aluminum-Doped Zinc Oxide Thin Films for Low Cost Applications.

    PubMed

    Park, Yong Seob; Park, Young; Kwon, Samyoung; Kim, Eung Kwon; Choi, Wonseok; Kim, Donguk; Kim, Minha; Lee, Jaehyeong

    2016-05-01

    Aluminum-doped zinc oxide (AZO) thin films were prepared on glass substrate using a magnetron sputtering system. In this work, a powder target was used as a source material for low cost applications, instead of a conventional sintered ceramic target. The effects of the hydrogen gas ratio on the electrical and optical properties of the AZO films. The hydrogen doped AZO (AZO:H) films had a hexagonal polycrystalline structure. A small amount of hydrogen gas deteriorated the electrical and optical properties of the AZO:H films. However, these properties improved, as the H2/(H2 + Ar) gas ratio increased. The AZO:H films grown at an H2/(H2+Ar) ratio of 10% showed good properties for low cost applications, such as a low resistivity of 1.35 x 10(-3) Ω-cm, high average transmittance of 83.1% in the visible range of light. PMID:27483879

  18. Improvement in micro-structural and mechanical properties of zinc film by surface treatment with low temperature argon plasma

    NASA Astrophysics Data System (ADS)

    Behera, Debadhyan; Mishra, Dilip K.; Pradhan, Siddhartha K.; Sakthivel, Ramasamy; Mohanty, Swagatika

    2011-11-01

    Nanocrystalline zinc films were deposited on gold coated borosilicate glass substrates by thermal evaporation method using zinc powders as the source material and then treated with argon plasma at various temperatures. From X-ray diffraction study, the as-deposited films are found to be metallic Zn and polycrystalline in nature. The crystalline nature improves with the increase of temperature up to 200 °C and decreases with the further increase of temperature to 300 °C. The binding energy observed for Zn 2p3/2, and the binding energy separation between Zn 2p3/2 and Zn 2p1/2 in the X-ray photoelectron spectrum indicate that the films are metallic zinc films. Transmission electron microscopic study shows hexagonal shaped grains having size ∼58 nm upon treatment with Ar plasma. It is clearly shown the grain growth and distinct grain boundary with the increase in temperature. The average Young's modulus (E) and hardness (H) are measured to be 84 GPa and 4.0 GPa for as-deposited film, whereas 98 GPa and 5.8 GPa for plasma treated film at 200 °C. The enhancement in mechanical properties is attributed to improvement in crystalline nature of the film and better interlinking between grains and boundaries.

  19. Effect of nitrogen doping on structural, morphological, optical and electrical properties of radio frequency magnetron sputtered zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Perumal, R.; Hassan, Z.

    2016-06-01

    Zinc oxide receives remarkable attention due to its several attractive physical properties. Zinc oxide thin films doped with nitrogen were grown by employing RF magnetron sputtering method at room temperature. Doping was accomplished in gaseous medium by mixing high purity nitrogen gas along with argon sputtering gas. Structural studies confirmed the high crystalline nature with c-axis oriented growth of the nitrogen doped zinc oxide thin films. The tensile strain was developed due to the incorporation of the nitrogen into the ZnO crystal lattice. Surface roughness of the grown films was found to be decreased with increasing doping level was identified through atomic force microscope analysis. The presenting phonon modes of each film were confirmed through FTIR spectral analysis. The increasing doping level leads towards red-shifting of the cut-off wavelength due to decrement of the band gap was identified through UV-vis spectroscopy. All the doped films exhibited p-type conductivity was ascertained using Hall measurements and the obtained results were presented.

  20. Preparation, crystal structures and properties of zinc complexes containing Bis(oxazoline) ligand

    NASA Astrophysics Data System (ADS)

    Sun, Ying; Jia, Wei-Guo; Li, Dan-Dan; Hao, Xiu-Yun; Zhou, Ying-Hua

    2015-12-01

    Three zinc complexes ([(DMOX)ZnX2], X = Cl (1), Br (2) or I (3)), where DMOX is 4,5-dihydro-2-(4,5-dihydro-4,4-dimethyloxazol-2-yl)-4,4-dimethyloxazole), have been fully characterized by single crystal X-ray diffraction, UV-vis, NMR and IR spectroscopy. Moreover, all zinc complexes showed activities in catalyzing hydrolysis of 4-nitrophenyl acetate (4-NA). And active species have been determined by pH titrations of [(DMOX)ZnI2] in catalyzing hydrolysis of 4-NA.

  1. Study of Thermodynamic Properties of Zinc-Blende Semiconductors:. Temperature and Pressure Dependences

    NASA Astrophysics Data System (ADS)

    Hieu, Ho Khac; Hung, Vu Van

    Using the statistical moment method (SMM), the temperature and pressure dependences of thermodynamic quantities of zinc-blende-type semiconductors have been investigated. The analytical expressions of the nearest-neighbor distances, the change of volumes and the mean-square atomic displacements (MSDs) have been derived. Numerical calculations have been performed for a series of zinc-blende-type semiconductors: GaAs, GaP, GaSb, InAs, InP and InSb. The agreement between our calculations and both earlier other theoretical results and experimental data is a support for our new theory in investigating the temperature and pressure dependences of thermodynamic quantities of semiconductors.

  2. Dynamics of linker residues modulate the nucleic acid binding properties of the HIV-1 nucleocapsid protein zinc fingers.

    PubMed

    Zargarian, Loussiné; Tisné, Carine; Barraud, Pierre; Xu, Xiaoqian; Morellet, Nelly; René, Brigitte; Mély, Yves; Fossé, Philippe; Mauffret, Olivier

    2014-01-01

    The HIV-1 nucleocapsid protein (NC) is a small basic protein containing two zinc fingers (ZF) separated by a short linker. It is involved in several steps of the replication cycle and acts as a nucleic acid chaperone protein in facilitating nucleic acid strand transfers occurring during reverse transcription. Recent analysis of three-dimensional structures of NC-nucleic acids complexes established a new property: the unpaired guanines targeted by NC are more often inserted in the C-terminal zinc finger (ZF2) than in the N-terminal zinc finger (ZF1). Although previous NMR dynamic studies were performed with NC, the dynamic behavior of the linker residues connecting the two ZF domains remains unclear. This prompted us to investigate the dynamic behavior of the linker residues. Here, we collected 15N NMR relaxation data and used for the first time data at several fields to probe the protein dynamics. The analysis at two fields allows us to detect a slow motion occurring between the two domains around a hinge located in the linker at the G35 position. However, the amplitude of motion appears limited in our conditions. In addition, we showed that the neighboring linker residues R29, A30, P31, R32, K33 displayed restricted motion and numerous contacts with residues of ZF1. Our results are fully consistent with a model in which the ZF1-linker contacts prevent the ZF1 domain to interact with unpaired guanines, whereas the ZF2 domain is more accessible and competent to interact with unpaired guanines. In contrast, ZF1 with its large hydrophobic plateau is able to destabilize the double-stranded regions adjacent to the guanines bound by ZF2. The linker residues and the internal dynamics of NC regulate therefore the different functions of the two zinc fingers that are required for an optimal chaperone activity.

  3. Poly(methyl methacrylate)/layered zinc sulfide nanocomposites: Preparation, characterization and the improvements in thermal stability, flame retardant and optical properties

    SciTech Connect

    Wang, Biao; Zhou, Keqing; Jiang, Saihua; Shi, Yongqian; Wang, Bibo; Gui, Zhou; Hu, Yuan

    2014-08-15

    Highlights: • Layered zinc sulfide (LZnS) was synthesized successfully via hydrothermal method. • We prepare PMMA/LZnS nanocomposites by in situ bulk polymerization of MMA. • PMMA/LZnS nanocomposites were investigated by TGA, DSC, MCC, UV–vis and PL test. • The thermal stability, flame retardant and optical properties of PMMA are improved. - Abstract: Layered zinc sulfide (LZnS) was synthesized successfully via hydrothermal method and poly(methyl methacrylate) (PMMA)/layered zinc sulfide nanocomposites were obtained by in situ bulk polymerization of methyl methacrylate (MMA). X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the as-synthesized layered zinc sulfide and PMMA/layered zinc sulfide nanocomposites. Microscale combustion calorimeter (MCC), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) were used to test the thermal properties of the composites. Ultraviolet visible (UV–vis) transmittance spectra and photoluminence (PL) spectra were obtained to investigate the optical properties of the composites. From the results, the thermal degradation temperature is increased by 20–50 °C, the peak of heat release rate (pHRR) and total heat release (THR) are both decreased by above 30%, and the photoluminence intensity is enhanced with the increasing loading of layered zinc sulfide.

  4. Effect of additions of zinc stearate on the properties of sintered Nd-Fe-B magnets

    NASA Astrophysics Data System (ADS)

    Popov, A. G.; Gerasimov, E. G.; Terent'ev, P. B.; Gaviko, V. S.; Shunyaev, K. Yu.; Mikhailova, T. L.; Vas'kovskii, V. O.; Kulesh, N. A.

    2013-04-01

    Zinc stearate additions have been used to increase the remanence of sintered Nd-Fe-B magnets produced by the powder metallurgy without powder pressing. Zinc stearate acts as an internal lubricant, i.e., it decreases the friction forces between the particles and favors an increase in the degree of texture of the powders, which is induced by the magnetic field. It is shown that the density and the magnetic hysteresis characteristics of sintered magnets produced using additions of 0.15 wt % zinc stearate exceeds the corresponding values obtained for magnets produced without this addition at a filling density of powders in containers of more than 2.9 and 3.0 g/cm3 in dry and wet states, respectively. Using additions of zinc stearate in the amount of 0.15% with respect to the weight of the powder, magnets with a density of 7.55 g/cm3, B r = 14.02 kG, H c = 7.91 kOe, and ( BH)max = 46.1 MG Oe have been produced.

  5. Electromechanical properties of amorphous indium-gallium-zinc-oxide transistors structured with an island configuration on plastic

    NASA Astrophysics Data System (ADS)

    Park, Chang Bum; Na, Hyung Il; Yoo, Soon Sung; Park, Kwon-Shik

    2016-03-01

    A comparative study of the electromechanical properties was carried out on a low-temperature-processed amorphous indium-gallium-zinc-oxide thin-film transistor, particularly with regard to the structural design of the device under the stress accumulation of an outward bending surface. Shown herein is the reliable electromechanical integrity of island-structured devices against the mechanical strain at bending radii of mm order. The onset of crack strain also closely corresponded to the electrical failure of the stressed device. These results revealed that the island configuration on the bending surface effectively suppresses the stress accumulation on sheets composed of inorganic stacked layers in a uniaxial direction.

  6. Solution processed zinc oxide nanopyramid/silver nanowire transparent network films with highly tunable light scattering properties

    NASA Astrophysics Data System (ADS)

    Mehra, Saahil; Christoforo, Mark G.; Peumans, Peter; Salleo, Alberto

    2013-05-01

    Metal nanowire transparent networks are promising replacements to indium tin oxide (ITO) transparent electrodes for optoelectronic devices. While the transparency and sheet resistance are key metrics for transparent electrode performance, independent control of the film light scattering properties is important to developing multifunctional electrodes for improved photovoltaic absorption. Here we show that controlled incorporation of ZnO nanopyramids into a metal nanowire network film affords independent, highly tunable control of the scattering properties (haze) with minimal effects on the transparency and sheet resistance. Varying the zinc oxide/silver nanostructure ratios prior to spray deposition results in sheet resistances, transmission (600 nm), and haze (600 nm) of 6-30 Ω □-1, 68-86%, and 34-66%, respectively. Incorporation of zinc oxide nanopyramid scattering agents into the conducting nanowire mesh has a negligible effect on mesh connectivity, providing a straightforward method of controlling electrode scattering properties. The decoupling of the film scattering power and electrical characteristics makes these films promising candidates for highly scattering transparent electrodes in optoelectronic devices and can be generalized to other metal nanowire films as well as carbon nanotube transparent electrodes.

  7. Mechanical Properties of Silicone Rubber Acoustic Lens Material Doped with Fine Zinc Oxide Powders for Ultrasonic Medical Probe

    NASA Astrophysics Data System (ADS)

    Yamamoto, Noriko; Yohachi; Yamashita; Itsumi, Kazuhiro

    2009-07-01

    The mechanical properties of high-temperature-vulcanization silicone (Q) rubber doped with zinc oxide (ZnO) fine powders have been investigated to develop an acoustic lens material with high reliability. The ZnO-doped Q rubber with an acoustic impedance (Z) of 1.46×106 kg·m-2·s-1 showed a tear strength of 43 N/mm and an elongation of 560%. These mechanical property values were about 3 times higher than those of conventional acoustic Q lens materials. The ZnO-doped Q rubbers also showed a lower abrasion loss. These superior characteristics are attributable to the microstructure with fewer origins of breaks; few pores and spherical fine ZnO powder. The high mechanical properties of ZnO-doped Q rubber acoustic lenses enable higher performance during long-life and safe operation during diagnosis using medical array probe applications.

  8. Soil properties affecting toxicity of zinc to soil microbial properties in laboratory-spiked and field-contaminated soils.

    PubMed

    Smolders, Erik; Buekers, Jurgen; Oliver, Ian; McLaughlin, Mike J

    2004-11-01

    The effects of soil properties and zinc (Zn) availability on the toxicity of Zn to soil microbial processes are poorly understood. Three soil microbial processes--potential nitrification rate (PNR), substrate (glucose)-induced respiration (SIR), and a maize residue respiration (MRR)--were measured in 15 European topsoils (pH 3.0-7.5; total Zn 7-191 mg/kg) that were freshly spiked with ZnCl2. The Zn toxicity thresholds of 20 to 50% effective concentrations (EC20s and EC50s) based on total concentrations of Zn in soil varied between 5- and 26-fold among soils, depending on the assay. The Zn toxicity thresholds based on Zn concentrations in soil solution varied at least 10-fold more than corresponding total metal thresholds. Soil pH had no significant effect on soil total Zn toxicity thresholds, whereas significant positive correlations were found between these thresholds and background Zn for the PNR and SIR test (r = 0.74 and 0.71, respectively; log-log correlations). No such trend was found for the MRR test. Soil solution-based thresholds showed highly significant negative correlations with soil pH for all assays that might be explained by competition of H+ for binding sites, as demonstrated for aquatic species. The microbial assays were also applied to soils collected under galvanized pylons (three sites) where concentrations of total Zn were up to 2,100 to 3,700 mg Zn/kg. Correlations between concentrations of total Zn and microbial responses were insignificant at all sites even though spiking reference samples to equivalent concentrations reduced microbial activities up to more than 10-fold. Differences in response between spiked and field soils are partly but not completely attributed to the large differences in concentrations of Zn in soil solution. We conclude that soil pH has no significant effect on Zn toxicity to soil microbial processes in laboratory-spiked soils, and we suggest that community tolerance takes place at both background and elevated Zn

  9. Electron depletion and accumulation regions in n-type copper-hexadecafluoro-phthalocyanine and their effects on electronic properties

    NASA Astrophysics Data System (ADS)

    Wang, Haibo; Liu, Zengtao; Fai Lo, Ming; Wai Ng, Tsz; Yan, Donghang; Lee, Chun-Sing

    2012-03-01

    We investigated interfacial electronic structures of organic/inorganic heterojunctions formed between copper-hexadecafluoro-phthalocyanine (F16CuPc) and molybdenum trioxide or lead monoxide by ultraviolet and x-ray photoemission spectroscopies. Obvious energy level bending in F16CuPc shows the formation of electron depletion and accumulation regions in its contact with molybdenum and lead oxides, respectively. Effects of these depletion/accumulation zones were studied via electronic characteristics of field-effect transistors constructed with these heterojunctions as active layers. Finally, a summary about the heterojunction including organic semiconductor (n-type and p-type) and metal oxide was given, which demonstrated that organic semiconductors can form various space charge regions like conventional inorganic semiconductors.

  10. Influence of a Boron Precursor on the Growth and Optoelectronic Properties of Electrodeposited Zinc Oxide Thin Film.

    PubMed

    Tsin, Fabien; Thomere, Angélica; Bris, Arthur Le; Collin, Stéphane; Lincot, Daniel; Rousset, Jean

    2016-05-18

    Highly transparent and conductive materials are required for many industrial applications. One of the interesting features of ZnO is the possibility to dope it using different elements, hence improving its conductivity. Results concerning the zinc oxide thin films electrodeposited in a zinc perchlorate medium containing a boron precursor are presented in this study. The addition of boron to the electrolyte leads to significant effects on the morphology and crystalline structure as well as an evolution of the optical properties of the material. Varying the concentration of boric acid from 0 to 15 mM strongly improves the compactness of the deposit and increases the band gap from 3.33 to 3.45 eV. Investigations were also conducted to estimate and determine the influence of boric acid on the electrical properties of the ZnO layers. As a result, no doping effect effect by boron was demonstrated. However, the role of boric acid on the material quality has also been proven and discussed. Boric acid strongly contributes to the growth of high quality electrodeposited zinc oxide. The high doping level of the film can be attributed to the perchlorate ions introduced in the bath. Finally, a ZnO layer electrodeposited in a boron rich electrolyte was tested as front contact of a Cu(In, Ga)(S, Se)2 based solar cell. An efficiency of 12.5% was measured with a quite high fill factor (>70%) which confirms the high conductivity of the ZnO thin film. PMID:27111517

  11. Influence of a Boron Precursor on the Growth and Optoelectronic Properties of Electrodeposited Zinc Oxide Thin Film.

    PubMed

    Tsin, Fabien; Thomere, Angélica; Bris, Arthur Le; Collin, Stéphane; Lincot, Daniel; Rousset, Jean

    2016-05-18

    Highly transparent and conductive materials are required for many industrial applications. One of the interesting features of ZnO is the possibility to dope it using different elements, hence improving its conductivity. Results concerning the zinc oxide thin films electrodeposited in a zinc perchlorate medium containing a boron precursor are presented in this study. The addition of boron to the electrolyte leads to significant effects on the morphology and crystalline structure as well as an evolution of the optical properties of the material. Varying the concentration of boric acid from 0 to 15 mM strongly improves the compactness of the deposit and increases the band gap from 3.33 to 3.45 eV. Investigations were also conducted to estimate and determine the influence of boric acid on the electrical properties of the ZnO layers. As a result, no doping effect effect by boron was demonstrated. However, the role of boric acid on the material quality has also been proven and discussed. Boric acid strongly contributes to the growth of high quality electrodeposited zinc oxide. The high doping level of the film can be attributed to the perchlorate ions introduced in the bath. Finally, a ZnO layer electrodeposited in a boron rich electrolyte was tested as front contact of a Cu(In, Ga)(S, Se)2 based solar cell. An efficiency of 12.5% was measured with a quite high fill factor (>70%) which confirms the high conductivity of the ZnO thin film.

  12. Toxicity of Functional Nano-Micro Zinc Oxide Tetrapods: Impact of Cell Culture Conditions, Cellular Age and Material Properties

    PubMed Central

    Papavlassopoulos, Heike; Mishra, Yogendra K.; Kaps, Sören; Paulowicz, Ingo; Abdelaziz, Ramzy; Elbahri, Mady; Maser, Edmund; Adelung, Rainer; Röhl, Claudia

    2014-01-01

    With increasing production and applications of nanostructured zinc oxide, e.g., for biomedical and consumer products, the question of safety is getting more and more important. Different morphologies of zinc oxide structures have been synthesized and accordingly investigated. In this study, we have particularly focused on nano-micro ZnO tetrapods (ZnO-T), because their large scale fabrication has been made possible by a newly introduced flame transport synthesis approach which will probably lead to several new applications. Moreover, ZnO-T provide a completely different morphology then classical spherical ZnO nanoparticles. To get a better understanding of parameters that affect the interactions between ZnO-T and mammalian cells, and thus their biocompatibility, we have examined the impact of cell culture conditions as well as of material properties on cytotoxicity. Our results demonstrate that the cell density of fibroblasts in culture along with their age, i.e., the number of preceding cell divisions, strongly affect the cytotoxic potency of ZnO-T. Concerning the material properties, the toxic potency of ZnO-T is found to be significantly lower than that of spherical ZnO nanoparticles. Furthermore, the morphology of the ZnO-T influenced cellular toxicity in contrast to surface charges modified by UV illumination or O2 treatment and to the material age. Finally, we have observed that direct contact between tetrapods and cells increases their toxicity compared to transwell culture models which allow only an indirect effect via released zinc ions. The results reveal several parameters that can be of importance for the assessment of ZnO-T toxicity in cell cultures and for particle development. PMID:24454775

  13. Toxicity of functional nano-micro zinc oxide tetrapods: impact of cell culture conditions, cellular age and material properties.

    PubMed

    Papavlassopoulos, Heike; Mishra, Yogendra K; Kaps, Sören; Paulowicz, Ingo; Abdelaziz, Ramzy; Elbahri, Mady; Maser, Edmund; Adelung, Rainer; Röhl, Claudia

    2014-01-01

    With increasing production and applications of nanostructured zinc oxide, e.g., for biomedical and consumer products, the question of safety is getting more and more important. Different morphologies of zinc oxide structures have been synthesized and accordingly investigated. In this study, we have particularly focused on nano-micro ZnO tetrapods (ZnO-T), because their large scale fabrication has been made possible by a newly introduced flame transport synthesis approach which will probably lead to several new applications. Moreover, ZnO-T provide a completely different morphology then classical spherical ZnO nanoparticles. To get a better understanding of parameters that affect the interactions between ZnO-T and mammalian cells, and thus their biocompatibility, we have examined the impact of cell culture conditions as well as of material properties on cytotoxicity. Our results demonstrate that the cell density of fibroblasts in culture along with their age, i.e., the number of preceding cell divisions, strongly affect the cytotoxic potency of ZnO-T. Concerning the material properties, the toxic potency of ZnO-T is found to be significantly lower than that of spherical ZnO nanoparticles. Furthermore, the morphology of the ZnO-T influenced cellular toxicity in contrast to surface charges modified by UV illumination or O2 treatment and to the material age. Finally, we have observed that direct contact between tetrapods and cells increases their toxicity compared to transwell culture models which allow only an indirect effect via released zinc ions. The results reveal several parameters that can be of importance for the assessment of ZnO-T toxicity in cell cultures and for particle development.

  14. Preparation, characterization and properties of novel covalently surface-functionalized zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Sato, Moriyuki; Harada, Hajime; Morito, Shigekazu; Fujita, Yasuhisa; Shimosaki, Shunsuke; Urano, Takeshi; Nakamura, Morihiko

    2010-05-01

    Novel covalently surface-modified zinc oxide (ZnO) nanoparticles (NP) (ZHIE) were successfully prepared, which have organic chains composed of hydrophilic amide and urethane linkages, and terminal amino groups on the surfaces, using zinc acetate monohydrate. FTIR spectroscopy, X-ray analysis and TEM observation suggested that the resultant ZHIE NPs have the mean sizes of about 10 nm in diameters, the organic chains linking the amino groups in the terminals and wurtzite crystal structure. UV-vis absorption spectrum of the ZHIE NPs in methanol showed maximum absorption band at 348 nm, supporting the TEM observations. Photoluminescent spectrum measurements depicted that the ZHIE NPs show broad visible emission band on the basis of trapped-electron emission. Cytotoxicity and phagocytosis assays suggested that the ZHIE NPs are noncytotoxic, and the ZHIE-labeled zymosan particles derived by conjugation of the ZHIE NPs with zymosan are internalized into the cells and generate fluorescence based on the ZHIE NPs.

  15. Electronic and magnetic properties of zinc blende half-metal superlattices

    NASA Astrophysics Data System (ADS)

    Fong, C. Y.; Qian, M. C.; Pask, J. E.; Yang, L. H.; Dag, S.

    2004-01-01

    Zinc blende half-metallic compounds such as CrAs, with large magnetic moments and high Curie temperatures, are promising materials for spintronic applications. We explore layered materials, consisting of alternating layers of zinc blende half-metals, by first principles calculations, and find that superlattices of (CrAs)1(MnAs)1 and (CrAs)2(MnAs)2 are half-metallic with magnetic moments of 7.0μB and 14.0μB per unit cell, respectively. We discuss the nature of the bonding and half-metallicity in these materials and, based on the understanding acquired, develop a simple expression for the magnetic moment in such materials. We explore the range of lattice constants over which half-metallicity is manifested, and suggest corresponding substrates for growth in thin film form.

  16. Synthesis, characterization, thermal and DNA-binding properties of new zinc complexes with 2-hydroxyphenones.

    PubMed

    Mrkalić, Emina; Zianna, Ariadni; Psomas, George; Gdaniec, Maria; Czapik, Agnieszka; Coutouli-Argyropoulou, Evdoxia; Lalia-Kantouri, Maria

    2014-05-01

    The neutral mononuclear zinc complexes with 2-hydroxyphenones (ketoH) having the formula [Zn(keto)2(H2O)2] and [Zn(keto)2(enR)], where enR stands for a N,N'-donor heterocyclic ligand such as 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2'-dipyridylamine (dpamH), have been synthesized and characterized by IR, UV and (1)H NMR spectroscopies. The 2-hydroxyphenones are chelated to the metal ion through the phenolate and carbonyl oxygen atoms. The crystal structures of [bis(2-hydroxy-4-methoxy-benzophenone)(2,2'-bipyridine)zinc(II)] dimethanol solvate and [bis(2-hydroxy-benzophenone)(2,2'-bipyridine)zinc(II)] dimethanol solvate have been determined by X-ray crystallography. The thermal stability of the zinc complexes has been investigated by simultaneous TG/DTG-DTA technique. The ability of the complexes to bind to calf-thymus DNA (CT DNA) has been studied by UV-absorption and fluorescence emission spectroscopy as well as viscosity measurements. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA and the corresponding binding constants to DNA have been calculated and evaluated. The complexes most probably bind to CT DNA via intercalation as concluded by studying the viscosity of a DNA solution in the presence of the complexes. Competitive studies with ethidium bromide (EB) have shown that the reported complexes can displace the DNA-bound EB, suggesting strong competition with EB for the intercalation site. PMID:24561277

  17. Purification of properties of dihydroorotase, a zinc-containing metalloenzyme in Clostridium oroticum.

    PubMed Central

    Taylor, W H; Taylor, M L; Balch, W E; Gilchrist, P S

    1976-01-01

    Dihydroorotase +4,5-L-dihydro-orotate amidohydrolase [EC 3.5.2.3]), which catalyzes the reversible cyclization of N-carbamyl-L-aspartate to L-dihydroorotate, has been purified from orotate-grown Clostridium oroticum. The enzyme is homogeneous when subjected to polyacrylamide gel electrophoresis and is stable at pH 7.6 in 0.3 M NaCl containing 10 muM ZnSO4. The enzyme has a molecular weight of approximately 110,000. Sodium dodecyl sulfate gel electrophoresis, using three different buffer systems, indicated the enzyme is composed of two subunits, each having a molecular weight of 55,000. Dihydroorotase is shown by atomic absorption spectroscopy to be a zinc-containing metalloenzyme with 4 g-atoms of zinc per 110,000 g of protein. The pH optima for the conversion of N-carbamyl-L-aspartate to L-dihydroorotate and for L-dihydroorotate to N-carbamyl-L-aspartate are pH 6.0 and 8.2, respectively. The Km values for N-carbamyl-L-aspartate and for L-dihydroorotate are 0.13 and 0.07 mM, respectively. Inhibitor studies indicate that zinc may be involved in the catalytic activity of the enzyme. Images PMID:8424

  18. Spectral and Electroluminescent Properties of Binuclear Zinc Complexes with Halogen-Substituted Derivatives of 1,2,4-Triazole

    NASA Astrophysics Data System (ADS)

    Kopylova, T. N.; Degtyarenko, K. M.; Samsonova, L. G.; Gadirov, R. M.; Gusev, A. N.; Shul'gin, V. F.; Meshkova, S. B.

    2015-03-01

    Spectral properties of binuclear zinc complexes in chloroform solutions and polyvinylcarbazole (PVC) films are investigated. It is demonstrated that incorporation of a halogen atom (chlorine or bromine) in a ligand benzene ring leads to a small shift of the spectrum toward the red region and a reduction of the fluorescence quantum yield. The fluorescence and phosphorescence spectra at T = 77K are investigated. The fluorescence undergoes a blue shift of about 30 nm and multiply increases in the intensity, and the phosphorescence is observed at 540-580 nm. The phosphorescence lifetime is estimated. The electroluminescent properties of metal complexes in structures with thermal vacuum spin coating of complexes and in PVC films are investigated.

  19. Structural and electronic properties of ni-doped ZnO in zinc-blende phase: A DFT investigations

    NASA Astrophysics Data System (ADS)

    Haq, Bakhtiar Ul; Ahmed, R.; Afaq, A.; Shaari, A.; Zarshenas, M.

    2012-09-01

    In the present work investigations of structural and electronic properties of nickel doped ZnO in zinc-blende phase have been done in the framework of density functional theory. In doping process 25% cations (Zn atoms) have been replaced by Ni atoms. Wu-Cohen parameterized Generalized Gradient Approximation (GGA-WC) is used for exchange and correlation energy functional treatment. Our calculations for structural properties reveal a reduction in lattice constant with Ni doping. Whereas the spin polarized electronic structures show metallic behavior of ZnO in the presence of Ni impurity atoms for both up and down spin configuration. Moreover we present calculated density of states to understand the effect of Ni doping on ZnO.

  20. Zinc poisoning

    MedlinePlus

    ... other materials to make industrial items such as paint, dyes, and more. These combination substances can be ... Compounds used to make paint, rubber, dyes, wood preservatives, and ... Zinc chloride Zinc oxide (relatively nonharmful) Zinc ...

  1. Synthesis of zinc oxide particles coated multiwalled carbon nanotubes: Dielectric properties, electromagnetic interference shielding and microwave absorption

    SciTech Connect

    Song, Wei-Li; Cao, Mao-Sheng; Wen, Bo; Hou, Zhi-Ling; Cheng, Jin; Yuan, Jie

    2012-07-15

    Graphical abstract: A resistor–capacitor model could well describe the relationships between the structure and the dielectric properties, electromagnetic interference shielding and microwave-absorption of the composites in the frequency range of 2–18 GHz. The resonant behavior associated with the multiwalled carbon nanotubes/zinc oxide (MWCNTs/ZnO) interface greatly broadens the absorption band. Highlights: ► ZnO-immobilized on multiwalled carbon nanotubes (MWCNTs/ZnO) have resonant behavior. ► A resistor–capacitor model describes the relation between the structure and properties. ► The composite with 40 wt% MWCNTs/ZnO has good electromagnetic interference shielding. ► Two different types of absorption peaks are found in the MWCNTs/ZnO composites. ► The existence of MWCNTs/ZnO interface broadens the absorption band. -- Abstract: Zinc oxide (ZnO) nanoparticles were coated on the surfaces of multiwalled carbon nanotubes (MWCNTs). High resolution transmission electron microscopy images show that the wurtzite ZnO immobilized on the MWCNTs is single-crystalline with a preferential [0 0 0 2] growth direction. A capacitor was generated by the interface of ZnO and MWCNTs, and a resistor–capacitor model could well describe the relationships between the structure and the dielectric properties, electromagnetic interference shielding and microwave-absorption of the composites in the frequency range of 2–18 GHz. The network built by ZnO-immobilized MWCNTs could contribute to the improvement of electrical properties. Resonant peaks associated with the capacitor formed by the interface were observed in the microwave absorption spectra, which suggest that reflection–loss peaks greatly broadens the absorption bandwidth.

  2. Observations of interstellar zinc

    NASA Technical Reports Server (NTRS)

    Jura, M.; York, D.

    1981-01-01

    The International Ultraviolet Explorer observations of interstellar zinc toward 10 stars are examined. It is found that zinc is at most only slightly depleted in the interstellar medium; its abundance may serve as a tracer of the true metallicity in the gas. The local interstellar medium has abundances that apparently are homogeneous to within a factor of two, when integrated over paths of about 500 pc, and this result is important for understanding the history of nucleosynthesis in the solar neighborhood. The intrinsic errors in detecting weak interstellar lines are analyzed and suggestions are made as to how this error limit may be lowered to 5 mA per target observation.

  3. pH effect on structural and optical properties of nanostructured zinc oxide thin films

    SciTech Connect

    Munef, R. A.

    2015-03-30

    ZnO nanostructures were Deposited on Objekttrager glasses for various pH values by chemical bath deposition method using Zn (NO3)2·6H2O (zinc nitrate hexahydrate) solution at 75°C reaction temperature without any posterior treatments. The ZnO nanostructures obtained were characterized by X-ray Diffraction (XRD, UV). The structure was hexagonal and it was found that some peaks disappear with various pH values. The grain sizes of ZnO films increases from 22-to-29nm with increasing pH. The transmission of the films was (85-95%)

  4. Photoelectrical, optical, and transport properties of poly (3-hexylthiophene)-zinc sulfide hybrid nanocomposites

    SciTech Connect

    Singh, Beerandra; Kaur, Amarjeet

    2014-08-14

    We have synthesized nanocomposites of poly (3-hexylthiophene) (P3HT) at 273 K and zinc sulfide (ZnS) nanoparticles at 353 K by the chemical route method. The synthesis of these nanocomposites is confirmed by UV-visible, high resolution transmission electron microscope, and Raman spectroscopy. We have measured photocurrent of P3HT using 50 W tungsten lamp. The photoconductivity increases with concentration of ZnS in P3HT-ZnS composite. Temperature dependent dc conductivity of P3HT and its nanocomposites have been thoroughly investigated in light of Mott's variable range hopping.

  5. Relationship between microstructure and electronic properties of energetically deposited zinc tin oxide

    NASA Astrophysics Data System (ADS)

    Murdoch, Billy James; McCulloch, Dougal G.; Partridge, James G.

    2016-06-01

    Thin films of amorphous n-type zinc tin oxide have been energetically deposited from a filtered cathodic vacuum arc at moderate temperatures. The characteristics of these films span a range suitable for semiconductor devices and transparent conducting oxide interconnects with carrier concentration and mobility dependent on local bonding. X-ray photoelectron spectroscopy (XPS) and electron diffraction have revealed that acceptor-like Sn(II) bonding in the films decreased with increasing growth temperature, resulting in higher n-type carrier concentrations. XPS and in situ Ar plasma treatment showed that downward surface band bending resulted from OH attachment. Persistent photoconductivity was attributed to the photoionization of oxygen vacancies.

  6. Fundamental Properties of One-Dimensional Zinc Oxide Nanomaterials and Implementations in Various Detection Modes of Enhanced Biosensing

    NASA Astrophysics Data System (ADS)

    Hahm, Jong-in

    2016-05-01

    Recent bioapplications of one-dimensional (1D) zinc oxide (ZnO) nanomaterials, despite the short development period, have shown promising signs as new sensors and assay platforms offering exquisite biomolecular sensitivity and selectivity. The incorporation of 1D ZnO nanomaterials has proven beneficial to various modes of biodetection owing to their inherent properties. The more widely explored electrochemical and electrical approaches tend to capitalize on the reduced physical dimensionality, yielding a high surface-to-volume ratio, as well as on the electrical properties of ZnO. The newer development of the use of 1D ZnO nanomaterials in fluorescence-based biodetection exploits the innate optical property of their high anisotropy. This review considers stimulating research advances made to identify and understand fundamental properties of 1D ZnO nanomaterials, and examines various biosensing modes utilizing them, while focusing on the unique optical properties of individual and ensembles of 1D ZnO nanomaterials specifically pertaining to their bio-optical applications in simple and complex fluorescence assays.

  7. Synthesis and optical properties of zinc oxide nanoparticles grown on Sn-coated silicon substrate by thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Somvanshi, Divya; Jit, S.

    2013-01-01

    The Zinc oxide (ZnO) nanoparticles have been grown on n type silicon substrate using tin (Sn) metal as seed layer by a low cost thermal evaporation method. SEM images show that the ZnO nanoparticles have been uniformely grown on the whole substrate surface relatively perpendicular to the substrate. The Photoluminescence (PL) spectrum consists of strong UV emission at wavelength of 355 nm along with a broad near band edge (NBE) emission covering a wide range of wavelength from 370 to 550 nm. This broadening region exhibits blue, violet and green emission due to the presence of native defects such as zinc interstitial (Zni), oxygen vacancy (VO) and oxygen interstitial (Oi) in the band gap of ZnO. Raman spectroscopy shows the existence of E2 mode at 437 cm-1 which confirms the pure wurtzite hexagonal phase of ZnO. The optical and structural properties of ZnO nanoparticles could be explored for blue-violet light emitting diodes (LEDs) and gas sensing applications.

  8. Structural and spectral properties of a zinc(II) coordination polymer: a combined experimental and theoretical study.

    PubMed

    Hao, Jin-Ming; Li, Guang-Yue; Li, Yue-Hua; Cui, Guang Hua

    2014-10-15

    A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm=1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through π-π stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385nm and 450nm could respectively be assigned to the π→π(*) transition within the bbbm ligands and π→n transition from chloride anion to bbbm ligand.

  9. Tuning electrical properties in amorphous zinc tin oxide thin films for solution processed electronics.

    PubMed

    Chandra, R Devi; Rao, Manohar; Zhang, Keke; Prabhakar, Rajiv Ramanujam; Shi, Chen; Zhang, Jie; Mhaisalkar, Subodh G; Mathews, Nripan

    2014-01-22

    Solution processed zinc tin oxide (ZTO) thin film transistors (TFTs) were fabricated by varying the Zn/Sn composition. The addition of Sn to the zinc oxide (ZnO) films resulted in improved electrical characteristics, with devices of Zn0.7Sn0.3O composition showing the highest mobility of 7.7 cm(2)/(V s). An improvement in subthreshold swings was also observed, indicative of a reduction of the interfacial trap densities. Mobility studies at low temperature have been carried out, which indicated that the activation energy was reduced with Sn incorporation. Kelvin probe force microscopy was performed on the films to evaluate work function and correlated to the metal-semiconductor barrier indicating Zn0.7Sn0.3O films had the smallest barrier for charge injection. Organic-inorganic hybrid complementary inverters with a maximum gain of 10 were fabricated by integrating ZTO TFTs with poly-3-hexylthiophene (P3HT) transistors. PMID:24380364

  10. Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate–zinc layered hydroxide nanohybrid

    SciTech Connect

    Bashi, Abbas M.; Hussein, Mohd Zobir; Zainal, Zulkarnain; Tichit, Didier

    2013-07-15

    Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic–inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D–ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model. - Graphical abstract: The phenomenon indicates that the optical energy gap is enlarged with the increase of molar concentrations in 2,4-dichlorophenoxy acetate anion content into ZnO to create a ZLH–24D nanohybrid. - Highlights: • Nanohybrid was synthesized from 2,4-dichlorophenoxy acetate with-Zinc LHD, using wet chemistry. • Characterized using SEM, TEM, EDX, FTIR, XRD and TGA. • Ribbon-shaped 24D–Zn-layered hydroxide nanoparticles with (003) diffractions of 2.5 nm phase were synthesized.

  11. Structure and spectral properties of dinuclear zinc complex containing semicarbazonate ligands

    NASA Astrophysics Data System (ADS)

    Jing-Lin, Wang; Jiao, Feng; Mei-Ping, Xu; Bin-Sheng, Yang

    2011-04-01

    The dinuclear Zn 2+ complex [Zn(HSSC)OAc] 2·2DMF (H 2SSC = salicylaldehyde semicarbazone; HOAc = acetic acid; DMF = N,N-dimethylfomamide) was prepared and structurally characterized by single crystal X-ray. The basic structural unit of the complex is a dinuclear complex [Zn(HSSC)OAc] 2 in which the semicarbazone ligand adopts the phenol-imine form. The deprotonated phenol group forms a one-atom bridge between the two zinc centers, and both of the zinc centers are five-coordinated. The local coordination environment of Zn 2+ can be approximately considered as square pyramidal. UV spectral studies show that the H 2SSC provides strong binding of Zn 2+ in a 1:1 ratio in solution. The conditional binding constant of the complex is lg KZn-L = 12.89 ± 0.76 in 0.05 M Tris-HCl buffer at pH 7.4. The H 2SSC exhibits an enhanced fluorescence effect by the addition of Zn 2+, and affords an excellent selectivity for Zn 2+ under physiological conditions.

  12. Facile fabrication of various zinc-nickel citrate microspheres and their transformation to ZnO-NiO hybrid microspheres with excellent lithium storage properties

    NASA Astrophysics Data System (ADS)

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2015-02-01

    Zinc-nickel citrate microspheres are prepared by a simple aging process of zinc citrate solid microspheres in nickel nitrate solution. As the concentration of nickel nitrate solution increases, the morphology of the produced zinc-nickel citrate evolves from solid, yolk-shell to hollow microspheres. The formation mechanism of different zinc-nickel citrate microspheres is discussed. After annealing treatment of the corresponding zinc-nickel citrate microspheres in air, three different ZnO-NiO hybrid architectures including solid, yolk-shell and hollow microspheres can be successfully fabricated. When applied as the anode materials for lithium ion batteries, ZnO-NiO hybrid yolk-shell microspheres demonstrate the best electrochemical properties than solid and hollow counterparts. After 200th cycles, ZnO-NiO hybrid yolk-shell microspheres deliver a high reversible capacity of 1176 mA h g-1. The unique yolk-shell configuration, the synergetic effect between ZnO and NiO and the catalytic effect of metal Ni generated by the reduction of NiO during discharging process are responsible for the excellent lithium storage properties of ZnO-NiO hybrid yolk-shell microspheres.

  13. Effect of zinc concentration on the structural, electrical and magnetic properties of mixed Mn Zn and Ni Zn ferrites synthesized by the citrate precursor technique

    NASA Astrophysics Data System (ADS)

    Verma, Anjali; Chatterjee, Ratnamala

    2006-11-01

    Mixed manganese-zinc and nickel-zinc ferrites of composition Mn 0.2Ni 0.8-xZn xFe 2O 4 where x=0.4, 0.5 and 0.6 have been synthesized by the citrate precursor technique. Decomposition of the precursor at temperatures as low as 500 °C gives the ferrite powder. The ferrites have been investigated for their electrical and magnetic properties such as saturation magnetization, initial permeability, Curie temperature, AC-resistivity and dielectric constant as a function of sintering temperature and zinc content. Structural properties such as lattice parameter, grain size and density are also studied. The mixed compositions exhibited higher saturation magnetizations at sintering temperatures as low as 1200 °C. While the Curie temperature decreased with zinc content, the permeability was found to increase. The AC-resistivity ranged from 10 5-10 7 Ω cm and decreased with zinc content and sintering temperature. The dielectric constants were lower than those normally reported for the Mn-Zn ferrites. Samples sintered at 1400 °C densified to about 94% of the theoretical density and the grain size was of the order of about 1.5 μm for the samples sintered at 1200 °C and increased subsequently with sintering temperature.

  14. Facile fabrication of various zinc-nickel citrate microspheres and their transformation to ZnO-NiO hybrid microspheres with excellent lithium storage properties

    PubMed Central

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2015-01-01

    Zinc-nickel citrate microspheres are prepared by a simple aging process of zinc citrate solid microspheres in nickel nitrate solution. As the concentration of nickel nitrate solution increases, the morphology of the produced zinc-nickel citrate evolves from solid, yolk-shell to hollow microspheres. The formation mechanism of different zinc-nickel citrate microspheres is discussed. After annealing treatment of the corresponding zinc-nickel citrate microspheres in air, three different ZnO-NiO hybrid architectures including solid, yolk-shell and hollow microspheres can be successfully fabricated. When applied as the anode materials for lithium ion batteries, ZnO-NiO hybrid yolk-shell microspheres demonstrate the best electrochemical properties than solid and hollow counterparts. After 200th cycles, ZnO-NiO hybrid yolk-shell microspheres deliver a high reversible capacity of 1176 mA h g−1. The unique yolk-shell configuration, the synergetic effect between ZnO and NiO and the catalytic effect of metal Ni generated by the reduction of NiO during discharging process are responsible for the excellent lithium storage properties of ZnO-NiO hybrid yolk-shell microspheres. PMID:25684436

  15. Interaction Between Yeasts and Zinc

    NASA Astrophysics Data System (ADS)

    Nicola, Raffaele De; Walker, Graeme

    Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses

  16. The effect of Cu doping on the mechanical and optical properties of zinc oxide nanowires synthesized by hydrothermal route

    NASA Astrophysics Data System (ADS)

    Robak, Elżbieta; Coy, Emerson; Kotkowiak, Michał; Jurga, Stefan; Załęski, Karol; Drozdowski, Henryk

    2016-04-01

    Zinc oxide (ZnO) is a wide-bandgap semiconductor material with applications in a variety of fields such as electronics, optoelectronic and solar cells. However, much of these applications demand a reproducible, reliable and controllable synthesis method that takes special care of their functional properties. In this work ZnO and Cu-doped ZnO nanowires are obtained by an optimized hydrothermal method, following the promising results which ZnO nanostructures have shown in the past few years. The morphology of as-prepared and copper-doped ZnO nanostructures is investigated by means of scanning electron microscopy and high resolution transmission electron microscopy. X-ray diffraction is used to study the impact of doping on the crystalline structure of the wires. Furthermore, the mechanical properties (nanoindentation) and the functional properties (absorption and photoluminescence measurements) of ZnO nanostructures are examined in order to assess their applicability in photovoltaics, piezoelectric and hybrids nanodevices. This work shows a strong correlation between growing conditions, morphology, doping and mechanical as well as optical properties of ZnO nanowires.

  17. The effect of Cu doping on the mechanical and optical properties of zinc oxide nanowires synthesized by hydrothermal route.

    PubMed

    Robak, Elżbieta; Coy, Emerson; Kotkowiak, Michał; Jurga, Stefan; Załęski, Karol; Drozdowski, Henryk

    2016-04-29

    Zinc oxide (ZnO) is a wide-bandgap semiconductor material with applications in a variety of fields such as electronics, optoelectronic and solar cells. However, much of these applications demand a reproducible, reliable and controllable synthesis method that takes special care of their functional properties. In this work ZnO and Cu-doped ZnO nanowires are obtained by an optimized hydrothermal method, following the promising results which ZnO nanostructures have shown in the past few years. The morphology of as-prepared and copper-doped ZnO nanostructures is investigated by means of scanning electron microscopy and high resolution transmission electron microscopy. X-ray diffraction is used to study the impact of doping on the crystalline structure of the wires. Furthermore, the mechanical properties (nanoindentation) and the functional properties (absorption and photoluminescence measurements) of ZnO nanostructures are examined in order to assess their applicability in photovoltaics, piezoelectric and hybrids nanodevices. This work shows a strong correlation between growing conditions, morphology, doping and mechanical as well as optical properties of ZnO nanowires.

  18. Mechanical and piezoelectric properties of zinc oxide nanorods grown on conductive textile fabric as an alternative substrate

    NASA Astrophysics Data System (ADS)

    Khan, Azam; Hussain, Mushtaque; Nur, Omer; Willander, Magnus

    2014-08-01

    The present research is devoted to understanding the mechanism and causes of variation in the piezoelectric potential generated from vertically aligned zinc oxide (ZnO) nanorods (NRs), which were grown on a conductive textile fabric as an alternative substrate by using the aqueous chemical growth method. The piezoelectric voltage was harvested from vertically aligned ZnO NRs having different physical parameters by using atomic force microscopy in contact mode and the variation in the generated piezoelectricity was investigated. The generated output potential indicates that different physical parameters such aspect ratio, crystal size and lattice internal crystal strain have a strong influence on the piezoelectric properties of vertically aligned ZnO NRs, which were grown on a textile fabric. Presented results indicate that textiles can be used as an alternative substrate just like the other conventional substrates, because our results are similar/better than many reported works on conventional substrates.

  19. Structural and magnetic properties of zinc ferrite thin films irradiated by 90 keV neon ions

    NASA Astrophysics Data System (ADS)

    Gafton, E. V.; Bulai, G.; Caltun, O. F.; Cervera, S.; Macé, S.; Trassinelli, M.; Steydli, S.; Vernhet, D.

    2016-08-01

    The effects of 90 keV neon beam irradiation on the structure and magnetic properties of zinc ferrite thin films have been investigated through several methods, namely, X-ray diffraction technique, Vibrating Sample and SQUID magnetometers. Beforehand, the pristine have also been characterized using profilometry and microscopy techniques. In particular single-phase formation of the thin films deposited on monocrystalline Si (111) substrate by pulsed laser deposition technique was confirmed. Crystal lattice, coercivity, saturation magnetization have been studied for the first time, as a function of ion penetration depth and irradiation fluence. The chemical composition and the crystallinity of the films are not affected with the ion impact acting as a mechanical stress relief. On the contrary, both magnetization and coercivity are sensitive to Neq+ ion irradiation and exhibit different behaviours depending on the ion fluence range.

  20. Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

    SciTech Connect

    György, E.; Pérez del Pino, A.; Logofatu, C.; Duta, A.; Isac, L.

    2014-07-14

    Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τ{sub FWHM} ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 10{sup 4} Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

  1. Enhancement of the electrical properties of silver nanowire transparent conductive electrodes by atomic layer deposition coating with zinc oxide.

    PubMed

    Pham, Anh-Tuan; Nguyen, Xuan-Quang; Tran, Duc-Huy; Ngoc Phan, Vu; Duong, Thanh-Tung; Nguyen, Duy-Cuong

    2016-08-19

    Transparent conductive electrodes for applications in optoelectronic devices such as solar cells and light-emitting diodes are important components and require low sheet resistance and high transmittance. Herein, we report an enhancement of the electrical properties of silver (Ag) nanowire networks by coating with zinc oxide using the atomic layer deposition technique. A strong decrease in the sheet resistance of Ag nanowires, namely from 20-40 Ω/□ to 7-15 Ω/□, was observed after coating with ZnO. Ag nanowire electrodes coated with 200-cycle ZnO by atomic layer deposition show the best quality, with a sheet resistance of 11 Ω/□ and transmittance of 75%.

  2. Enhancement of the electrical properties of silver nanowire transparent conductive electrodes by atomic layer deposition coating with zinc oxide

    NASA Astrophysics Data System (ADS)

    Pham, Anh-Tuan; Nguyen, Xuan-Quang; Tran, Duc-Huy; Phan, Vu Ngoc; Duong, Thanh-Tung; Nguyen, Duy-Cuong

    2016-08-01

    Transparent conductive electrodes for applications in optoelectronic devices such as solar cells and light-emitting diodes are important components and require low sheet resistance and high transmittance. Herein, we report an enhancement of the electrical properties of silver (Ag) nanowire networks by coating with zinc oxide using the atomic layer deposition technique. A strong decrease in the sheet resistance of Ag nanowires, namely from 20-40 Ω/□ to 7-15 Ω/□, was observed after coating with ZnO. Ag nanowire electrodes coated with 200-cycle ZnO by atomic layer deposition show the best quality, with a sheet resistance of 11 Ω/□ and transmittance of 75%.

  3. Structural and optical properties of zinc oxide doped by V2O5 synthesized by solid-state reaction

    NASA Astrophysics Data System (ADS)

    Abaira, R.; Dammak, T.; Matoussi, A.; Younes, A.

    2016-03-01

    Vanadium doped zinc oxide with different vanadium concentration were synthesized by conventional solid state reaction. The structural and optical properties of ZnO: V2O5 pellets were studied by using a panalytic diffraktometer (X'pert) with Cu-K radiation, the UV-visible spectrophotometer and photoluminescence (PL). X-ray diffraction (XRD) show that all the samples have a wurtzite structure and grow mainly in the (101) orientation, we show also the presence of dominated phase Zn3 (VO4)2, Optical studied indicate a decrease in optical band gap energy, and photoluminescence (PL) spectra showed a strong visible emission band, energy position and intensity of this emission depends on the temperature measurement. The activate energy Ea has been fitted and studied using Arunis equation.

  4. Synthesis, structural and optical properties of 1-alkyl-2-(2'-tosylaminophenyl)-5-nitrobenzimidazoles and their zinc(II) complexes

    NASA Astrophysics Data System (ADS)

    Burlov, Anatolii S.; Koshchienko, Yurii V.; Kiskin, Mikhail A.; Nikolaevskii, Stanislav A.; Garnovskii, Dmitrii A.; Lermontov, Anatolii S.; Makarova, Nadegda I.; Metelitsa, Anatolii V.; Eremenko, Igor L.

    2016-01-01

    A series of novel benzimidazole derivatives 1-alkyl-2-(2'-tosylaminophenyl)-5-nitrobenzimidazoles with common formulas HL (1-3) (R = C2H5 (1); R = n-C3H7 (2); R = n-C4H9(3)) and their mononuclear zinc(II) complexes ZnL2 (4-6) have been synthesized in a molar ratio Zn: HL = 1:2 in methanol solutions. Formulation of 1-6 is based upon satisfactory C, H, N, S elemental analyses, IR and 1H, 13C NMR spectroscopies, while the structures of 2, 3, 5, 6 were determined by X-ray single-crystal diffraction. The optical properties of 1-6 were investigated.

  5. Enhancement of the electrical properties of silver nanowire transparent conductive electrodes by atomic layer deposition coating with zinc oxide

    NASA Astrophysics Data System (ADS)

    Pham, Anh-Tuan; Nguyen, Xuan-Quang; Tran, Duc-Huy; Phan, Vu Ngoc; Duong, Thanh-Tung; Nguyen, Duy-Cuong

    2016-08-01

    Transparent conductive electrodes for applications in optoelectronic devices such as solar cells and light-emitting diodes are important components and require low sheet resistance and high transmittance. Herein, we report an enhancement of the electrical properties of silver (Ag) nanowire networks by coating with zinc oxide using the atomic layer deposition technique. A strong decrease in the sheet resistance of Ag nanowires, namely from 20–40 Ω/□ to 7–15 Ω/□, was observed after coating with ZnO. Ag nanowire electrodes coated with 200-cycle ZnO by atomic layer deposition show the best quality, with a sheet resistance of 11 Ω/□ and transmittance of 75%.

  6. Enhancement of the electrical properties of silver nanowire transparent conductive electrodes by atomic layer deposition coating with zinc oxide.

    PubMed

    Pham, Anh-Tuan; Nguyen, Xuan-Quang; Tran, Duc-Huy; Ngoc Phan, Vu; Duong, Thanh-Tung; Nguyen, Duy-Cuong

    2016-08-19

    Transparent conductive electrodes for applications in optoelectronic devices such as solar cells and light-emitting diodes are important components and require low sheet resistance and high transmittance. Herein, we report an enhancement of the electrical properties of silver (Ag) nanowire networks by coating with zinc oxide using the atomic layer deposition technique. A strong decrease in the sheet resistance of Ag nanowires, namely from 20-40 Ω/□ to 7-15 Ω/□, was observed after coating with ZnO. Ag nanowire electrodes coated with 200-cycle ZnO by atomic layer deposition show the best quality, with a sheet resistance of 11 Ω/□ and transmittance of 75%. PMID:27378668

  7. Analysis of proton single-particle properties of zinc and germanium isotopes

    SciTech Connect

    Bespalova, O. V. Ermakova, T. A.; Klimochkina, A. A.; Romanovsky, E. A.; Spasskaya, T. I.

    2014-12-15

    Experimental proton single-particle energies in the vicinity of the Fermi energy for stable zinc and germanium isotopes are analyzed on the basis the dispersive optical model. The values found for the parameters of the dispersive optical potential are corrected with the aim of matching the total number of protons that is calculated with the aid of the function of Bardeen-Cooper-Schrieffer theory for the occupation probability for single-particle orbits with the charge number Z of the nucleus. The parameters of the dispersive optical potential are extrapolated on the basis of physically motivated arguments to the region of unstable isotopes in which the number N ranges between 34 and 50, and single-particle spectra are predicted by means of calculations with these parameters.

  8. Significant improvement in electronic properties of transparent amorphous indium zinc oxide through yttrium doping

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Yu, Zhigen; Huang, Yanhua; Xia, Yijie; Lai, Weng Soon; Gong, Hao

    2014-04-01

    One big challenge in transparent conducting oxides (TCOs) is to achieve high conductivity and mobility at a low processing temperature. Although optimized conductivity has been achieved in indium zinc oxide (IZO) without doping, it is still interesting to find whether doping can improve conductivity of IZO further. In this paper, we report a low processing temperature achievement of high conductivity and mobility of IZO through yttrium (Y) doping. We found that with different Y doping levels, room temperature fabricated amorphous IZO (a-IZO) samples can be controlled to exhibit either metallic or semiconductor characteristics. Y2O3 is demonstrated to be an effective doping source to achieve conductivity 300% higher than the non-doped IZO sample. Anomalously improved mobility of certain Y2O3-doped IZO samples compared with the non-doped IZO sample is found and analyzed. Besides, a low-temperature resistivity anomaly (semiconductor metal transition) phenomenon is observed and discussed.

  9. Crystalline perfection, spectroscopic investigations and transport properties of trisglycine zinc chloride NLO single crystal

    NASA Astrophysics Data System (ADS)

    Sugandhi, K.; Dinakaran, S.; Jose, M.; Uthrakumar, R.; Jeya Rejendran, A.; Bhagvannarayana, G.; Joseph, V.; Jerome Das, S.

    2010-09-01

    Bulk single crystals of trisglycine zinc chloride have been grown from aqueous solution by slow cooling technique. Single crystal and powder XRD analyses confirmed orthorhombic crystal structure with non-centrosymmetric space group Pbn2 1. High resolution X-ray diffraction results have established that the quality of the grown crystal is quite good for device fabrication. The crystal was characterized by FTIR and NMR spectral analyses. Optical absorption studies show that the material has very low absorption in the wavelength range 240-2000 nm. The analysis of absorption coefficient in the absorption region reveals a direct band gap of 4.21 eV. The crystal possesses remarkable thermal stability up to 229 °C. Photoconductivity studies of the grown crystal revealed the positive photoconducting nature. The grown crystal exhibited considerable hardness anisotropy with Vicker’s hardness tester. Dielectric constant and dielectric loss were calculated by varying frequencies at different temperatures.

  10. Growth and optical properties of quadrangular zinc oxide nanorods on copper-filled porous silicon

    NASA Astrophysics Data System (ADS)

    Yu, K.; Zhang, Y.; Luo, L.; Wang, W.; Zhu, Z.; Wang, J.; Cui, Y.; Ma, H.; Lu, W.

    Zinc oxide (ZnO) nanorods with quadrangular morphology have been successfully prepared on a copper-filled porous silicon substrate using a vapor phase transport method. Scanning electron microscopy showed that the diameters of the nanorods were scattered in a range of 100-400 nm and the lengths up to 2 μm. High-resolution transmission electron microscopy and a selected-area electron-diffraction pattern confirmed that the quadrangular ZnO nanorods had a single-crystal wurtzite structure and grew along the (0001) direction. The photoluminescence spectrum under excitation at 325 nm showed an ultraviolet emission at 386 nm and a strong broad green emission at 518 nm at room temperature.

  11. Photophysical and electrochemical properties of a dysprosium-zinc tetra(4-sulfonatophenyl)porphyrin complex.

    PubMed

    Chen, Wen-Tong; Liu, Dong-Sheng; Xu, Ya-Ping; Luo, Qiu-Yan; Pei, Yun-Peng

    2016-02-01

    A dysprosium-zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single-crystal X-ray diffraction analyses. Complex 1 features a three-dimensional (3-D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 Å(3), occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi-reversible wave with E1/2  = 0.30 V. PMID:26014749

  12. Effect of gamma irradiation on dielectric properties of manganese zinc nanoferrites

    SciTech Connect

    Angadi, V. Jagadeesha Rudraswamy, B.; Melagiriyappa, E.; Somashekarappa, H. M.; Nagabhushana, H.

    2014-04-24

    Naocrystalline ferrites Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.00, 0.25, 0.50, 0.75 and 1.00) were prepared by combustion method. The samples were characterized by XRD technique. The dielectric measurements were carried out in the frequency range 40 Hz to 100 MHz at room temperature. All the measurements were performed before and after gamma {sup 60}Co irradiation. The X-ray diffraction patterns revealed the formation of nanocrystalline and single-phase spinel structure. The lattice parameter decrease with zinc ion concentration and increased after the irradiation due to ferric ions of smaller radius converted to ferrous ions of larger radius. The dielectric behavior is attributed to the Maxwell-Wagner type interfacial polarization. The dielctric contant, dielectric loss and AC conductivity enhanced after the irradiation.

  13. Spectroscopic and radiative properties of Sm3+ ions in zinc borophosphate glasses

    NASA Astrophysics Data System (ADS)

    Hima Bindu, S.; Rajavardhana Rao, T.; Linga Raju, Ch

    2015-06-01

    The paper reports on the preparation and characterization of Sm3+ doped zinc borophosphate (ZBP) glasses. The density was measured and the corresponding molar volume was evaluated. The present glass system was investigated by the XRD, optical absorption, photoluminescence, decay curves and FTIR analysis. The Judd-Ofelt theory has been used to evaluate the JO intensity parameters (Ω2,4,6) and calculated oscillator strengths (ƒcal). Using JO intensity parameters, various radiative parameters such as transition probability (AR), radiative lifetime (τR), measured lifetime (τm), calculated branching ratios (βR), measured branching ratios (βm) have been calculated for the excited 4G5/2 level. The nature of the decay curves of 4G5/2 level for different Sm3+ ion concentration in all ZBP glasses has been analyzed and the lifetimes are noticed to decrease with increase of concentration.

  14. Photophysical and electrochemical properties of a dysprosium-zinc tetra(4-sulfonatophenyl)porphyrin complex.

    PubMed

    Chen, Wen-Tong; Liu, Dong-Sheng; Xu, Ya-Ping; Luo, Qiu-Yan; Pei, Yun-Peng

    2016-02-01

    A dysprosium-zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single-crystal X-ray diffraction analyses. Complex 1 features a three-dimensional (3-D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 Å(3), occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi-reversible wave with E1/2  = 0.30 V.

  15. Effect of sintering temperature on structural property of X-type barium-zinc hexaferrites

    NASA Astrophysics Data System (ADS)

    Kagdi, Amrin; Solanki, Neha; Jotania, Rajshree B.

    2016-05-01

    X-type Barium-Zinc hexaferrite powder with chemical composition Ba2Zn2Fe28O46 has been prepared using citrate gel auto combustion technique. The combusted powder waspre-heated at 550 °C for 4 hours followed by final calcinations of 1100 °C and 1250 °C for 5 hoursrespectively. Prepared hexaferrite samples were characterizedusingdifferent instrumental techniques such as FTIR and XRD. XRD analysis of the sample calcined at 1250 °C revealed formation of mono phase of X-type hexaferrite; while the sample calcined at 1100 °C shows multiphases of M, W and X-type hexaferrites. FTIR spectra of both samples show stretching of metal-oxide bands.

  16. Analysis of proton single-particle properties of zinc and germanium isotopes

    NASA Astrophysics Data System (ADS)

    Bespalova, O. V.; Ermakova, T. A.; Klimochkina, A. A.; Romanovsky, E. A.; Spasskaya, T. I.

    2014-12-01

    Experimental proton single-particle energies in the vicinity of the Fermi energy for stable zinc and germanium isotopes are analyzed on the basis the dispersive optical model. The values found for the parameters of the dispersive optical potential are corrected with the aim of matching the total number of protons that is calculated with the aid of the function of Bardeen-Cooper-Schrieffer theory for the occupation probability for single-particle orbits with the charge number Z of the nucleus. The parameters of the dispersive optical potential are extrapolated on the basis of physically motivated arguments to the region of unstable isotopes in which the number N ranges between 34 and 50, and single-particle spectra are predicted by means of calculations with these parameters.

  17. Observations of interstellar zinc

    NASA Technical Reports Server (NTRS)

    York, D. G.; Jura, M.

    1982-01-01

    IUE observations toward 10 stars have shown that zinc is not depleted in the interstellar medium by more than a factor of two, suggesting that its abundance may serve as a tracer of the true metallicity in the gas. A result pertinent to the history of nucleosynthesis in the solar neighborhood is that the local interstellar medium has abundances that appear to be homogeneous to within a factor of two, when integrated over paths of about 500 pc.

  18. 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. PMID:27253970

  19. 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.

  20. Composition-structure-property relationships for non-classical ionomer cements formulated with zinc-boron germanium-based glasses.

    PubMed

    Zhang, Xiaofang; Werner-Zwanziger, Ulrike; Boyd, Daniel

    2015-04-01

    Non-classical ionomer glasses like those based on zinc-boron-germanium glasses are of special interest in a variety of medical applications owning to their unique combination of properties and potential therapeutic efficacy. These features may be of particular benefit with respect to the utilization of glass ionomer cements for minimally invasive dental applications such as the atruamatic restorative treatment, but also for expanded clinical applications in orthopedics and oral-maxillofacial surgery. A unique system of zinc-boron-germanium-based glasses (10 compositions in total) has been designed using a Design of Mixtures methodology. In the first instance, ionomer glasses were examined via differential thermal analysis, X-ray diffraction, and (11)B MAS NMR spectroscopy to establish fundamental composition - structure-property relationships for the unique system. Secondly, cements were synthesized based on each glass and handling characteristics (working time, Wt, and setting time, St) and compression strength were quantified to facilitate the development of both experimental and mathematical composition-structure-property relationships for the new ionomer cements. The novel glass ionomer cements were found to provide Wt, St, and compression strength in the range of 48-132 s, 206-602 s, and 16-36 MPa, respectively, depending on the ZnO/GeO2 mol fraction of the glass phase. A lower ZnO mol fraction in the glass phase provides higher glass transition temperature, higher N4 rate, and in combination with careful modulation of GeO2 mol fraction in the glass phase provides a unique approach to extending the Wt and St of glass ionomer cement without compromising (in fact enhancing) compression strength. The data presented in this work provide valuable information for the formulation of alternative glass ionomer cements for applications within and beyond the dental clinic, especially where conventional approaches to modulating working time and strength exhibit co

  1. Effect of nickel doping on physical properties of zinc oxide thin films prepared by the spray pyrolysis method

    NASA Astrophysics Data System (ADS)

    Jlassi, M.; Sta, I.; Hajji, M.; Ezzaouia, H.

    2014-05-01

    In this study, undoped and nickel-doped zinc oxide thin films (ZnO:Ni) were deposited on glass substrates using a spray pyrolysis technique. The effects of the Zn concentration in the initial solution and the substrate temperature on the physical properties of the thin films are studied. The results show that the optimum Zn concentration and substrate temperature for preparation of basic undoped ZnO films with n-type conductivity and high optical transparency are 0.02 M and 350 °C, respectively. Then, by using these optimized deposition parameters, nickel-doped zinc oxide films are prepared. Surface morphology and crystalline structure of the films are investigated by atomic force microscopy (AFM) and X-ray diffractometer. X-ray diffraction (XRD) patterns show that the films are polycrystalline. The structural analysis shows that all the samples have a hexagonal structure. The crystallite size and the preferred orientation were calculated from the XRD data. From AFM investigations, the surface morphology of the nanostructured films is found to depend on the concentration of Ni. Optical measurements have shown that an increase in the Ni doping results in a reduction in the optical transmission of the layer, but it remains higher than 80% for Ni doping greater than 8 wt%. At the same time, the optical gap increases from 3.4 to 4 eV when the Ni ratio increases. The electrical measurements show that the resistance of the films varies with the duration of pulverization and the nickel content of the film. Low values for the electrical resistivity (around 103 Ω cm) were obtained for Ni-doped ZnO thin films.

  2. Imaging Mobile Zinc in Biology

    PubMed Central

    Tomat, Elisa; Lippard, Stephen J.

    2009-01-01

    Summary Trafficking and regulation of mobile zinc pools influence cellular functions and pathological conditions in multiple organs, including brain, pancreas, and prostate. The quest for a dynamic description of zinc distribution and mobilization in live cells fuels the development of increasingly sophisticated probes. Detection systems that respond to zinc binding with changes of their fluorescence emission properties have provided sensitive tools for mobile zinc imaging, and fluorescence microscopy experiments have afforded depictions of zinc distribution within live cells and tissues. Both small-molecule and protein-based fluorescent probes can address complex imaging challenges, such as analyte quantification, site-specific sensor localization, and real-time detection. PMID:20097117

  3. The electrical conduction properties of poly-crystalline indium-zinc-oxide film

    SciTech Connect

    Tomai, S.; Terai, K.; Junke, T.; Tsuruma, Y.; Ebata, K.; Yano, K.; Uraoka, Y.

    2014-02-28

    We have developed a high-mobility and high-uniform oxide semiconductor using poly-crystalline semiconductor material composed of indium and zinc (p-IZO). A typical conduction mechanism of p-IZO film was demonstrated by the grain boundary scattering model as in polycrystalline silicon. The grain boundary potential of the 2-h-annealed IZO film was calculated to be 100 meV, which was comparable to that of the polycrystalline silicon. However, the p-IZO thin film transistor (TFT) measurement shows rather uniform characteristics. It denotes that the mobility deterioration around the grain boundaries is lower than the case for low-temperature polycrystalline silicon. This assertion was made based on the difference of the mobility between the polycrystalline and amorphous IZO film being much smaller than is the case for silicon transistors. Therefore, we conclude that the p-IZO is a promising material for a TFT channel, which realizes high drift mobility and uniformity simultaneously.

  4. Structural and optical properties of DC reactive magnetron sputtered zinc aluminum oxide thin films

    SciTech Connect

    Kumar, B. Rajesh; Rao, T. Subba

    2014-10-15

    Highly transparent conductive Zinc Aluminum Oxide (ZAO) thin films have been deposited on glass substrates using DC reactive magnetron sputtering method. The thin films were deposited at 200 °C and post-deposition annealing from 15 to 90 min. XRD patterns of ZAO films exhibit only (0 0 2) diffraction peak, indicating that they have c-axis preferred orientation perpendicular to the substrate. Scanning electron microscopy (SEM) is used to study the surface morphology of the films. The grain size obtained from SEM images of ZAO thin films are found to be in the range of 20 - 26 nm. The minimum resistivity of 1.74 × 10{sup −4} Ω cm and an average transmittance of 92% are obtained for the thin film post annealed for 30 min. The optical band gap of ZAO thin films increased from 3.49 to 3.60 eV with the increase of annealing time due to Burstein-Moss effect. The optical constants refractive index (n) and extinction coefficient (k) were also determined from the optical transmission spectra.

  5. Physicomechanical properties of a zinc-reinforced glass ionomer restorative material.

    PubMed

    Al-Angari, Sarah S; Hara, Anderson T; Chu, Tien-Min; Platt, Jeffrey; Eckert, George; Cook, N Blaine

    2014-03-01

    We compared a zinc-reinforced glass ionomer restorative material (ChemFil Rock) with three commercially available glass ionomer cements (GICs), namely, Fuji IX GP Extra, Ketac Molar Quick Aplicap, and EQUIA Fil, with respect to fracture toughness, microhardness, roughness, and abrasive wear. Fracture toughness (KIC) was tested according to ISO 13586 (n = 10). Hardness, roughness, and abrasive wear were also tested (n = 9). Data were analyzed using the Wilcoxon rank-sum test with adjustment for multiple comparisons (α = 0.05). As compared with the other GICs ChemFil Rock exhibited a greater increase in surface roughness (P < 0.05) and lower microhardness (P < 0.01). The wear resistance of ChemFil Rock was comparable to that of the other GICs (P > 0.05). ChemFil Rock had significantly lower fracture toughness as compared with EQUIA Fil (P = 0.01) and significantly higher fracture toughness as compared with the other GICs (P < 0.02). In conclusion, as compared with the three other commercially available GICs, ChemFil Rock had intermediate fracture toughness, the lowest microhardness, and the greatest change in surface roughness.

  6. Magnetic properties and adsorptive performance of manganese-zinc ferrites/activated carbon nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhang, B. B.; Xu, J. C.; Xin, P. H.; Han, Y. B.; Hong, B.; Jin, H. X.; Jin, D. F.; Peng, X. L.; Li, J.; Gong, J.; Ge, H. L.; Zhu, Z. W.; Wang, X. Q.

    2015-01-01

    Owing to the unique microstructure and high specific surface area, activated carbon (AC) could act as an excellent adsorbent for wastewater treatment and good carrier for functional materials. In this paper, manganese-zinc ferrites (Mn0.5Zn0.5Fe2O4: MZF) were anchored into AC by hydrothermal method, resulting in the excellent magnetic response for AC nanocomposites in wastewater treatment. All results demonstrated the magnetic nanoparticles presented a spinel phase structure and existed in the pores of AC. The saturation magnetization (Ms) of MZF/AC nanocomposites increased with the ferrites content, while the pore volume and specific surface area declined. The Sample-5 possessed the specific surface area of 1129 m2 g-1 (close to 1243 m2 g-1 of AC) and Ms of 3.96 emu g-1. Furthermore, the adsorptive performance for organic dyes was studied and 99% methylene blue was adsorbed in 30 min. The magnetic AC nanocomposites could be separated easily from solution by magnetic separation technique.

  7. Effect of filler loading of nickel zinc ferrite on the tensile properties of PLA nanocomposites

    NASA Astrophysics Data System (ADS)

    Shahdan, Dalila; Ahmad, Sahrim Hj

    2013-05-01

    The mechanical strength of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90:10. The MPNC were prepared at constant mixing temperature at 180°C, mixing time of 15 min. and mixing speed of 100 rpm. In order to achieve a good dispersion of NiZn ferrite in the matrix, firstly an ultrasonic treatment had been employed to mix the LNR and NiZn ferrite for 1 hour. The MPNC of PLA/LNR/NiZn ferrite then were prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1-5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases the tensile strength also increases until an optimum value of filler loading was reached. The Young's modulus, tensile strength and elongation at break have also increased. The study proves that NiZn ferrite is excellent reinforcement filler in PLA matrix. Scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX) were meant to show the homogeneity dispersion of nanoparticles within the matrix and to confirm the elemental composition of NiZn ferrites-PLA/LNR nanocomposites respectively.

  8. Novel rapid synthesis of zinc oxide nanotubes via hydrothermal technique and antibacterial properties.

    PubMed

    Aal, Nadia Abdel; Al-Hazmi, Faten; Al-Ghamdi, Ahmed A; Al-Ghamdi, Attieh A; El-Tantawy, Farid; Yakuphanoglu, F

    2015-01-25

    ZnO nanotubes with the wurtzite structure have been successfully synthesized via simple hydrothermal solution route using zinc nitrate, urea and KOH for the first time. The structural, compositions and morphology architectures of the as synthesized ZnO nanotubes was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and high resolution transmission scanning electron microscopy (HRTEM). TEM showed that ZnO nanotubes exhibited a wall thickness of less than 2 nm, with an average diameter of 17 nm and the length is 2 μm. In addition, the antibacterial activity of ZnO nanotubes was carried out in vitro against two kinds of bacteria: gram - negative bacteria (G -ve) i.e. Escherichia coli (E. coli) and gram - positive bacteria (G +ve) i.e. Staphylococcus aureus. Therefore, this work demonstrates that simply synthesized ZnO nanotubes have excellent potencies, being ideal antibacterial agents for many biomedical applications.

  9. Different Binding Properties and Function of CXXC Zinc Finger Domains in Dnmt1 and Tet1

    PubMed Central

    Meilinger, Daniela; Bultmann, Sebastian; Fellinger, Karin; Hasenöder, Stefan; Wang, Mengxi; Qin, Weihua; Söding, Johannes; Spada, Fabio; Leonhardt, Heinrich

    2011-01-01

    Several mammalian proteins involved in chromatin and DNA modification contain CXXC zinc finger domains. We compared the structure and function of the CXXC domains in the DNA methyltransferase Dnmt1 and the methylcytosine dioxygenase Tet1. Sequence alignment showed that both CXXC domains have a very similar framework but differ in the central tip region. Based on the known structure of a similar MLL1 domain we developed homology models and designed expression constructs for the isolated CXXC domains of Dnmt1 and Tet1 accordingly. We show that the CXXC domain of Tet1 has no DNA binding activity and is dispensable for catalytic activity in vivo. In contrast, the CXXC domain of Dnmt1 selectively binds DNA substrates containing unmethylated CpG sites. Surprisingly, a Dnmt1 mutant construct lacking the CXXC domain formed covalent complexes with cytosine bases both in vitro and in vivo and rescued DNA methylation patterns in dnmt1−/− embryonic stem cells (ESCs) just as efficiently as wild type Dnmt1. Interestingly, neither wild type nor ΔCXXC Dnmt1 re-methylated imprinted CpG sites of the H19a promoter in dnmt1−/− ESCs, arguing against a role of the CXXC domain in restraining Dnmt1 methyltransferase activity on unmethylated CpG sites. PMID:21311766

  10. Crystal plane-dependent gas-sensing properties of zinc oxide nanostructures: experimental and theoretical studies.

    PubMed

    Kaneti, Yusuf V; Zhang, Zhengjie; Yue, Jeffrey; Zakaria, Quadir M D; Chen, Chuyang; Jiang, Xuchuan; Yu, Aibing

    2014-06-21

    The sensitivity of a metal oxide gas sensor is strongly dependent on the nature of the crystal surface exposed to the gas species. In this study, two types of zinc oxide (ZnO) nanostructures: nanoplates and nanorods with exposed (0001) and (10̄10) crystal surfaces, respectively, were synthesized through facile solvothermal methods. The gas-sensing results show that sensitivity of the ZnO nanoplates toward ethanol is two times higher than that of the ZnO nanorods, at an optimum operating temperature of 300 °C. This could be attributed to the higher surface area and the exposed (0001) crystal surfaces. DFT (Density Functional Theory) simulations were carried out to study the adsorption of ethanol on the ZnO crystal planes such as (0001), (10̄10), and (11̄20) with adsorbed O(-) ions. The results reveal that the exposed (0001) planes of the ZnO nanoplates promote better ethanol adsorption by interacting with the surface oxygen p (O2p) orbitals and stretching the O-H bond to lower the adsorption energy, leading to the sensitivity enhancement of the nanoplates. These findings will be useful for the fabrication of metal oxide nanostructures with specifically exposed crystal surfaces for improved gas-sensing and/or catalytic performance. PMID:24801357

  11. Temperature-dependent dielectric properties and line profile analysis of zinc-substituted copper ferrites

    NASA Astrophysics Data System (ADS)

    Lamani, A. R.; Jayanna, H. S.; Naveen, C. S.; Rajeeva, M. P.; Prasanna, G. D.; Chaturmukha, V. S.; Harish, B. M.; Suresh, S.; Avinash, B. S.

    2016-05-01

    Temperature dependence of dielectric constant and loss has been investigated for different compositions of Zinc substituted copper ferrites with general formula Cu1-xZnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) prepared by ceramic method. XRD analysis confirms all the samples exhibit single phase cubic spinel structure. The dielectric constant and loss of the sample were studied in the temperature ranges from RT to 1000K at different constant frequency. Samples of the composition with x = 0.8 show low dielectric loss up to a measured temperature around 770 °C at higher frequencies as compared to samples of other compositions. A plot of dielectric constant versus temperature shows a transition near the Curie temperature, an attempt is made to explain the possible mechanism for this observation. The dielectric constant increases slowly from 309°C to 770°C with temperature in the beginning and sharply decreases with increase in frequency for all the samples. The variation of tanδ with frequency shows cusps for all the samples except for x = 0.6. These variations have been explained on the basis of Koop's phenomenological theory. The variation of dielectric loss tangent with frequency showed maxima for the 1 KHz. These maxima are also found to shift towards low-frequency region as the content of Zn increases.

  12. Influence of the film properties on the plasma etching dynamics of rf-sputtered indium zinc oxide layers

    SciTech Connect

    Stafford, L.; Lim, W. T.; Pearton, S. J.; Chicoine, M.; Gujrathi, S.; Schiettekatte, F.; Park, Jae-Soung; Song, Ju-Il; Heo, Young-Woo; Lee, Joon-Hyung; Kim, Jeong-Joo; Kravchenko, I. I.

    2007-07-15

    The etching characteristics of indium zinc oxide (IZO) films were investigated using a high-density plasma in Ar, Ar/Cl{sub 2}, and Ar/CH{sub 4}/H{sub 2} chemistries. The IZO layers were deposited by means of rf magnetron sputtering, in which the target composition and growth temperature were varied to selectively tune the film properties. X-ray diffraction, elastic recoil detection, and Rutherford backscattering spectroscopy were used to determine the crystallization quality, atomic density, and composition of the as-deposited IZO films. As the In/(In+Zn) composition ratio in the IZO layer increases, the etch yield in Ar and Ar/Cl{sub 2} plasmas remains fairly constant, indicating that the etching dynamic is essentially independent of the film properties. In sharp contrast, a strong increase of the IZO etch yield with the In/(In+Zn) fraction is observed in Ar/CH{sub 4}/H{sub 2} plasma due to the preferential desorption of the group-III etch products. By comparing these experimental data to the predictions of a simple rate model accounting for preferential desorption effects, it is concluded that the balance between etching and polymer deposition in the Ar/CH{sub 4}/H{sub 2} plasma plays an important role in the evolution of the IZO etch rate with the In concentration fraction.

  13. Ultra-violet Sensing Characteristic and Field Emission Properties of Vertically Aligned Aluminum Doped Zinc Oxide Nanorod Arrays

    SciTech Connect

    Mamat, M. H.; Malek, M. F.; Musa, M. Z.; Khusaimi, Z.; Rusop, M.

    2011-05-25

    Ultra-violet (UV) sensing behavior and field emission characteristic have been investigated on vertically aligned aluminum (Al) doped zinc oxide (ZnO) nanorod arrays prepared using sol-gel immersion method. Uniform and high coverage density of ZnO nanorod arrays have been successfully deposited on seeded-catalyst coated substrates. The synthesized nanorods have diameter sizes between 50 nm to 150 nm. The XRD spectra show Al doped ZnO nanorod array has high crystallinity properties with the dominancy of crystal growth along (002) plane or c-axis. UV photoresponse measurement indicates that Al doped ZnO nanorod array sensitively detects UV light as shown by conductance increment after UV illumination exposure. The nanorod array shows good field emission properties with low turn on field and threshold field at 2.1 V/{mu}m and 5.6 V/{mu}m, respectively. The result suggested that Al doped ZnO nanorod arrays prepared by low-cost sol-gel immersion method show promising result towards fabrication of multi applications especially in UV photoconductive sensor and field emission displays.

  14. Disordered zinc in Zn4Sb3 with phonon-glass and electron-crystal thermoelectric properties

    NASA Astrophysics Data System (ADS)

    Snyder, G. Jeffrey; Christensen, Mogens; Nishibori, Eiji; Caillat, Thierry; Iversen, Bo Brummerstedt

    2004-07-01

    By converting waste heat into electricity, thermoelectric generators could be an important part of the solution to today's energy challenges. The compound Zn4Sb3 is one of the most efficient thermoelectric materials known. Its high efficiency results from an extraordinarily low thermal conductivity in conjunction with the electronic structure of a heavily doped semiconductor. Previous structural studies have been unable to explain this unusual combination of properties. Here, we show through a comprehensive structural analysis using single-crystal X-ray and powder-synchrotron-radiation diffraction methods, that both the electronic and thermal properties of Zn4Sb3 can be understood in terms of unique structural features that have been previously overlooked. The identification of Sb3- ions and Sb24- dimers reveals that Zn4Sb3 is a valence semiconductor with the ideal stoichiometry Zn13Sb10. In addition, the structure contains significant disorder, with zinc atoms distributed over multiple positions. The discovery of glass-like interstitial sites uncovers a highly effective mechanism for reducing thermal conductivity. Thus Zn4Sb3 is in many ways an ideal 'phonon glass, electron crystal' thermoelectric material.

  15. Disordered Zinc in Zn4Sb3 with Phonon-Glass and Electron-Crystal Thermoelectric Properties

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey; Christensen, Mogens; Nishibori, Eiji; Caillat, Thierry; Brummerstedt Iversen, Bo

    2004-01-01

    By converting waste heat into electricity, thermoelectric generators could be an important part of the solution to today's energy challenges. The compound Zn4Sb3 is one of the most efficient thermoelectric materials known. Its high efficiency results from an extraordinarily low thermal conductivity in conjunction with the electronic structure of a heavily doped semiconductor. Previous structural studies have been unable to explain this unusual combination of properties. Here, we show through a comprehensive structural analysis using single-crystal X-ray and powder-synchrotron-radiation diffraction methods, that both the electronic and thermal properties of Zn4Sb3 can be understood in terms of unique structural features that have been previously overlooked. The identification of Sb3- ions and Sb-2(4-) dimers reveals that Zn4Sb3 is a valence semiconductor with the ideal stoichiometry Zn13Sb10. In addition, the structure contains significant disorder, with zinc atoms distributed over multiple positions. The discovery of glass-like interstitial sites uncovers a highly effective mechanism for reducing thermal conductivity. Thus Zn4Sb3 is in many ways an ideal 'phonon glass, electron crystal' thermoelectric material.

  16. Assessing three different ranges of amounts of silver nanoparticle dopants on the ethanol sensing properties of zinc oxide

    NASA Astrophysics Data System (ADS)

    Mohammadrezaei, Ameneh; Afzalzadeh, Reza; Mohsen Hosseini-Golgoo, Seyed

    2012-03-01

    The effects of silver nanoparticle (SNP) dopants on the ethanol sensing properties of zinc oxide (ZnO) bulk sensors were investigated. ZnO powder was mixed with various weight percentages of SNPs in the range of 0-1.8 wt% and then all samples were sintered at 860 °C. X-ray diffractometry was used to determine the crystal structure of the doped samples. Scanning electron microscopy was used to characterize the structure of the specimens. The electrical and gas-sensing properties of the specimens were assessed at different temperatures. Three different ranges of additive amount were distinguished based on the sensing behavior of the samples as a result of the solubility of SNPs in ZnO samples. In the first range, a tiny amount of the SNPs (˜0.025 wt%) can be dissolved in the ZnO lattice, so the resistance and response of the bulk ZnO sensors are decreased. In the second range (0.025% < wt% <0.7%), those parameters are increased, revealing that Ag cannot be dissolved in ZnO at higher concentration. Best recovery time is achieved in this range at 0.7 wt% of SNP dopants. In the third range (wt% > 0.7%), the resistance is observed to increase and the response to decrease with a high accumulation of Ag clusters on the grain surfaces. Moreover, the working temperature is reduced by increasing the amount of SNPs.

  17. Aggregation properties of bis(salicylaldiminato)zinc(II) Schiff-base complexes and their Lewis acidic character.

    PubMed

    Consiglio, Giuseppe; Failla, Salvatore; Finocchiaro, Paolo; Oliveri, Ivan Pietro; Di Bella, Santo

    2012-01-14

    The synthesis, characterization, (1)H NMR, optical absorption and fluorescent properties of a series of amphiphilic Schiff-base bis(salicylaldiminato)zinc(II) complexes are reported. Detailed (1)H NMR, DOSY NMR, optical absorption and fluorescence spectroscopy studies indicate the existence of aggregate species in solutions of non-coordinating solvents. The degree of aggregation is related to the nature of the bridging diamine. Chloroform solutions of complexes where the bridging diamine contains a naphthalene or the pyridine nucleus are always characterized by the presence of defined dimer aggregates, whereas oligomeric aggregates are likely formed by complexes where the bridging diamine contains a benzene ring. In coordinating solvents or in the presence of coordinating species, a complete deaggregation of the complexes occurs, because of the axial coordination to the Zn(II) ion, accompanied by considerable changes in the (1)H NMR and optical absorption spectra. The effect of the alkyl chains length seems to play a minor role in the aggregation properties, as noticed by (1)H NMR data, optical absorption and fluorescence spectra, which remain almost unaltered on changing the chain length. PMID:22005842

  18. Influence of low sputtering pressure on structural, electrical and optical properties of Al-doped zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Zhang, Zengguang; Tang, Yang; Chen, Jingyun; Chen, Jie

    2016-08-01

    Aluminum-doped zinc oxide thin films were deposited without intentional heating by radio-frequency magnetron sputtering. The sputtering pressure varied from 0.02 Pa to 0.32 Pa while the deposition power was kept at 240 W for all depositions. The structural properties of as-deposited films were analyzed by X-ray diffraction and scanning electron microscopy, indicating that the deposited films have a strong preferred c-axis (002) orientation perpendicular to the substrate regardless of sputtering pressure. The minimum resistivity of 6.4×10-4 Ω cm is obtained at 0.05 Pa, which is mainly influenced by the hall mobility, rather than carrier concentration. The highest transmittance could be ~80% on average in the visible range under various working pressures, and the largest bandgap achieved is about 3.82 eV. The ultraviolet emission peaks in photoluminescence spectra are centered at about 360 nm. A new mechanism is proposed to explain the dependence of the electrical and optical properties on structural evolution of deposited films.

  19. The influence of zinc on the blood serum of cadmium-treated rats through the rheological properties.

    PubMed

    Moussa, Sherif Aa; Alaamer, Abdulaziz; Abdelhalim, Mohamed A K

    2016-01-01

    The blood rheological properties serve as an important indicator for the early detection of many diseases. This study aimed to investigate the influence of zinc (Zn) on blood serum of cadmium (Cd) intoxication-treated male rats through the rheological properties. The rheological parameters were measured in serum of control, Cd, and Cd+Zn groups at wide range of shear rates (225-1875 s(-1)). The rat blood serum showed a non-significant change in cadmium-treated rats' %torque and shear stress at the lower shear rates (200-600 s(-1)) while a significant increase was observed at the higher shear rates (650-1875 s(-1)) compared with the control. The rat blood serum viscosity increased significantly in the Cd-treated group at each shear rate compared with the control. The viscosity and shear rate exhibited a non-Newtonian behavior for all groups. The increase in blood serum viscosity in Cd-treated male rats might be attributed to destruction or changes in the non-clotting proteins, and other blood serum components. In Cd+Zn-treated rats, the rat blood serum viscosity values returned nearer to the control values at each shear rate. Our results confirmed that Zn displaced Cd or compete with the binding sites for Cd uptake.

  20. Luminescence properties of Tb3+-doped zinc phosphate glasses for green laser application

    NASA Astrophysics Data System (ADS)

    Juárez-Batalla, J.; Meza-Rocha, A. N.; Muñoz H., G.; Camarillo, I.; Caldiño, U.

    2016-08-01

    Tb3+-doped zinc phosphate glasses of composition in mol%: (100.0 - x)Zn(PO3)2 - xTb2O3, x = 0.6, 1.0, 2.0 and 5.0, were prepared by conventional melt quenching technique and characterized by photoluminescence and decay time spectroscopy. The integrated intensities of the 5D4 → 7F5 (green at 541 nm) and 5D3 → 7F4 (blue at 435 nm) emissions and their intensity ratios IG/IB upon 350 nm excitation have been evaluated as function of Tb3+ concentration. The CIE1931 color of the glasses excited at 350 nm varies from turquoise to green by increasing the Tb3+ content. The increased IG/IB ratio up to a factor of 364 for the phosphor with the highest Tb3+ content (ZP5Tb) is consistent with the observed shift toward the green region in the CIE coordinates, so that the ZP5Tb glass exhibits a green color purity of 66.9% with chromaticity coordinates (0.290, 0.581), being very close to those (0.29, 0.60) of European Broadcasting Union illuminant green. This interesting feature of the ZP5Tb phosphor, together with an experimental branching ratio larger than 60% of the 5D4 → 7F5 green emission, highlights its capability as solid state green laser pumped by AlGaN (350 nm) LEDs. The decay time profiles of the 5D3 level resulted to be non-exponential for all the studied concentrations due to energy transfer between Tb3+ ions through cross-relaxation. Such decay profiles were well fitted to the Inokuti-Hirayama model for S = 6, which indicates that an electric dipole-dipole interaction might be the dominant mechanism in the cross-relaxation energy transfer occurring in Tb3+ ion clusters.

  1. Zinc concentration effect on structural, optical and electrical properties of Cd{sub 1−x}Zn{sub x}Se thin films

    SciTech Connect

    Akaltun, Yunus; Yıldırım, M. Ali; Ateş, Aytunç; Yıldırım, Muhammet

    2012-11-15

    Highlights: ► Cd{sub 1−x}Zn{sub x}Se thin films were deposited using SILAR method. ► The electron effective mass, refractive index, dielectric constant values were calculated by using the energy bandgap values as a function of the zinc concentration (x). ► The resistivity and activation energy changed as a function of the zinc concentration (x). -- Abstract: Cd{sub 1−x}Zn{sub x}Se thin films with different compositions (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were deposited on glass substrates using successive ionic layer adsorption and reaction (SILAR) method at room temperature and ambient pressure. The zinc concentration (x) effect on the structural, morphological, optical and electrical properties of Cd{sub 1−x}Zn{sub x}Se thin films were investigated. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies showed that all the films exhibited polycrystalline nature and were covered well on glass substrates. The energy dispersive X-ray (EDAX) analysis confirmed nearly stoichiometric deposition of the films. The energy bandgap values were changed from 1.99 to 2.82 eV depending on the zinc concentration. Bowing parameter was calculated as 0.08 eV. The electron effective mass (m{sub e}*/m{sub o}), refractive index (n), optical static and high frequency dielectric constants (ε{sub o}, ε{sub ∞}) values were calculated by using the energy bandgap values as a function of the zinc concentration. The resistivity values of the films changed between 10{sup 5} and 10{sup 7} Ω cm with increasing zinc concentration at room temperature.

  2. Mid- to long-wavelength infrared surface plasmon properties in doped zinc oxides

    NASA Astrophysics Data System (ADS)

    Cleary, Justin W.; Snure, Michael; Leedy, Kevin D.; Look, David C.; Eyink, Kurt; Tiwari, Ashutosh

    2012-09-01

    This work investigates properties of surface plasmons on doped metal oxides in the 2-20 μm wavelength regime. By varying the stoichiometry in pulse laser deposited Ga and Al doped ZnO, the plasmonic properties can be controlled via a fluctuating free carrier concentration. This deterministic approach may enable one to develop the most appropriate stoichometry of ZnAlO and ZnGaO in regards to specific plasmonic applications for particular IR wavelengths. Presented are theoretical and experimental investigations pertaining to ZnAlO and ZnGaO as surface plasmon host materials. Samples are fabricated via pulsed laser deposition and characterized by infrared ellipsometry and Hall-effect measurements. Complex permittivity spectra are presented, as well as plasmon properties such as the field propagation lengths and penetration depths, in the infrared range of interest. Drude considerations are utilized to determine how the optical properties may change with doping. Finite element simulations verify these plasmonic properties. These materials not only offer potential use as IR plasmon hosts for sensor applications, but also offer new integrated device possibilities due to stoichiometric control of electrical and optical properties.

  3. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    PubMed

    Feng, Pei; Wei, Pingpin; Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2), and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  4. Characterization of Mechanical and Biological Properties of 3-D Scaffolds Reinforced with Zinc Oxide for Bone Tissue Engineering

    PubMed Central

    Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam1/2, and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially. PMID:24498185

  5. Magnetic properties and adsorptive performance of manganese–zinc ferrites/activated carbon nanocomposites

    SciTech Connect

    Zhang, B.B.; Xu, J.C.; Xin, P.H.; Han, Y.B.; Hong, B.; Jin, H.X.; Jin, D.F.; Peng, X.L.; Li, J.; Gong, J.; Ge, H.L.; Zhu, Z.W.; Wang, X.Q.

    2015-01-15

    Owing to the unique microstructure and high specific surface area, activated carbon (AC) could act as an excellent adsorbent for wastewater treatment and good carrier for functional materials. In this paper, manganese–zinc ferrites (Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}: MZF) were anchored into AC by hydrothermal method, resulting in the excellent magnetic response for AC nanocomposites in wastewater treatment. All results demonstrated the magnetic nanoparticles presented a spinel phase structure and existed in the pores of AC. The saturation magnetization (Ms) of MZF/AC nanocomposites increased with the ferrites content, while the pore volume and specific surface area declined. The Sample-5 possessed the specific surface area of 1129 m{sup 2} g{sup −1} (close to 1243 m{sup 2} g{sup −1} of AC) and Ms of 3.96 emu g{sup −1}. Furthermore, the adsorptive performance for organic dyes was studied and 99% methylene blue was adsorbed in 30 min. The magnetic AC nanocomposites could be separated easily from solution by magnetic separation technique. - Graphical abstract: The Sample-5 presented both good magnetic response and high BET surface area up to 1129 m{sup 2} g{sup −1} (close to AC of 1243 m{sup 2} g{sup −1}), which could be separated completely for about 60 s. MZF/AC nanocomposites (Sample-3, 4, 5) in our work could be used as the magnetic absorbents, which could be separated easily by an outer magnet after the MB adsorption. - Highlights: • Mn{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} (MZF) as few as possible was implanted into activated carbon (AC) for the higher surface area. • Sample-5 possessed the high specific surface area (1129 m{sup 2} g{sup −1}) and the suitable Ms (3.96 emu g{sup −1}). • Methylene blue was adsorbed almost completely by MZF/AC nanocomposites in 30 min. • MZF/AC nanocomposites were separated easily from solution by magnetic separation technique.

  6. Nonstoichiometry and its effect on the magnetic properties of a manganese-zinc ferrite

    SciTech Connect

    Inaba, Hideaki

    1995-11-01

    The effect of oxygen nonstoichiometry on physical and magnetic properties of a Mn-Zn ferrite has been studied by using annealed samples under various oxygen pressures and temperatures. The dependence of oxygen nonstoichiometry on disaccommodation and Fe{sup 2+} content changed at the stoichiometric composition, and the lattice parameter became maximum at the stoichiometric composition. These results suggest that Mn-Zn ferrites have two different defect structures: cation vacancies in cation-deficient regions and oxygen vacancies in anion-deficient regions. Initial permeability was maximum and power los was minimum at the stoichiometric composition, suggesting the importance of the number of point defects for the magnetic properties.

  7. Influence of the Cation Ratio on Optical and Electrical Properties of Amorphous Zinc-Tin-Oxide Thin Films Grown by Pulsed Laser Deposition.

    PubMed

    Bitter, Sofie; Schlupp, Peter; Bonholzer, Michael; von Wenckstern, Holger; Grundmann, Marius

    2016-04-11

    Continuous composition spread (CCS) methods allow fast and economic exploration of composition dependent properties of multielement compounds. Here, a CCS method was applied for room temperature pulsed laser deposition (PLD) of amorphous zinc-tin-oxide to gain detailed insight into the influence of the zinc-to-tin cation ratio on optical and electrical properties of this ternary compound. Our CCS approach for a large-area offset PLD process utilizes a segmented target and thus makes target exchange or movable masks in the PLD chamber obsolete. Cation concentrations of 0.08-0.82 Zn/(Zn + Sn) were achieved across single 50 × 50 mm(2) glass substrates. The electrical conductivity increases for increasing tin content, and the absorption edge shifts to lower energies. The free carrier concentration can be tuned from 10(20) to 10(16) cm(-3) by variation of the cation ratio from 0.1 to 0.5 Zn/(Zn + Sn).

  8. Electrical properties of zinc-sulfide films produced by close-spaced vacuum sublimation

    SciTech Connect

    Kurbatov, D. I.

    2013-09-15

    The electrical properties of ZnS films produced by closed-space vacuum sublimation are studied. From analysis of the current-voltage characteristics under conditions of space-charge-limited currents and of the temperature dependences of conductivity, the energy levels of localized states in the band gap of the ZnS films are determined.

  9. Investigations on spectroscopic properties of Pr3+ and Nd3+ doped zinc-alumino-sodium-phosphate (ZANP) glasses

    NASA Astrophysics Data System (ADS)

    Brahmachary, K.; Rajesh, D.; Babu, S.; Ratnakaram, Y. C.

    2014-05-01

    Zinc-alumino-sodium-phosphate (ZANP) glasses doped with rare earth metal ions (Nd3+ and Pr3+) with different concentrations (0.5, 1.0, 1.5, 2.0 and 2.5 mol%) were prepared by melt quenching technique. X-ray diffraction, SEM with EDS, Raman spectra, FTIR-spectra, DTA, absorption and luminescence spectra were recorded at room temperature for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images confirmed the amorphous nature of the glass samples. The EDS spectrum of doped and undoped glasses reveals the chemical composition present in them. Structural information of these glass matrices was provided by FTIR and Raman spectra. From DTA analysis, the glass transition temperature (Tg) and crystallization temperature (Tc) were determined. From the absorption spectra, the Judd-Ofelt (J-O) parameters, Ωλ (λ = 2, 4 and 6) and other radiative properties like transition probabilities (AR), radiative lifetimes (τR) and branching ratios (βR) were evaluated. Branching ratios and stimulated emission cross-sections show that 4F3/2 → 4I11/2 transition of Nd3+ ion and 3P0 → 3H4 transition of Pr3+ ion of the glasses under investigation have strong emission at 1060 and 490 nm respectively. The results obtained were compared with reports on similar glasses.

  10. Photophysical Properties of an Alkyne-Bridged Bis(zinc porphyrin)-Perylene Bis(dicarboximide) Derivative

    NASA Astrophysics Data System (ADS)

    Odom, Susan A.; Kelley, Richard F.; Ohira, Shino; Ensley, Trenton R.; Huang, Chun; Padilha, Lazaro A.; Webster, Scott; Coropceanu, Veaceslav; Barlow, Stephen; Hagan, David J.; van Stryland, Eric W.; Brédas, Jean-Luc; Anderson, Harry L.; Wasielewski, Michael R.; Marder, Seth R.

    2009-09-01

    We report the synthesis, electrochemistry, and photophysical properties of a new donor-acceptor-donor molecule in which the meso carbon atoms of two zinc porphyrin (POR) units are linked through ethynylene bridges to the 1,7-positions of a central perylene-3,4:9,10-bis(dicarboximide) (PDI). In contrast to previously studied systems incorporating POR and PDI groups, this alkyne-based derivative shows evidence of through-bond electronic coupling in the ground state; the new chromophore exhibits absorption features similar to those of its constituent parts as well as lower energy features (at wavelengths up to ca. 1000 nm), presumably arising from donor-acceptor interactions. Transient absorption measurements show that excitation at several visible and near-IR wavelengths results in the formation of an excited-state species with a lifetime of 290 ps in 1% (v/v) pyridine in toluene. The absorption spectrum of this species resembles the sum of the spectra for the chemically generated radical cation and radical anion of the chromophore. The chromophore shows moderate two-photon absorption cross sections (2000-7000 GM) at photon wavelengths close to the onset of its low-energy one-photon absorption feature.

  11. Single crystal growth and enhancing effect of glycine on characteristic properties of bis-thiourea zinc acetate crystal

    NASA Astrophysics Data System (ADS)

    Anis, Mohd; Muley, G. G.

    2016-08-01

    A single crystal of glycine-doped bis-thiourea zinc acetate (G-BTZA) with a dimension of 15 × 6 × 4 mm3 has been grown using the slow solution evaporation technique. The structural parameters of the crystals were determined using the single crystal XRD technique. The increase in optical transparency of the doped BTZA crystal was ascertained in the range of 200 to 900 nm using UV-visible spectral analysis. The improved optical band gap of the G-BTZA crystal is found to be 4.19 eV, and vital optical constants have been calculated using the transmittance data. The influence of glycine on the mechanical parameters of the BTZA crystal has been investigated via microhardness studies. The thermal stability of pure and doped BTZA crystals has been determined by employing the thermogravimetric and differential thermal analysis technique. The improvement in the dielectric properties of the BTZA crystal after the addition of glycine has been evaluated in a temperature range of 30 to 120 °C at a frequency of 100 KHz. The SHG efficiency of the glycine-doped BTZA crystal is found to be much higher than KDP and BTZA crystal material in a Kurtz-Perry powder analysis.

  12. Effect of sintering temperature on the magnetic properties of zinc substituted lithium ferrites synthesized using sol-gel method

    NASA Astrophysics Data System (ADS)

    Reddy, P. Vijaya Bhasker; Reddy, S. Narender; Reddy, Ch. Gopal

    2013-06-01

    Polycrystalline zinc substituted lithium (Li-Zn) ferrite samples with chemical formula, Li0.5-x/2ZnxFe2.5-x/2O4(x = 0.6), were synthesized using sol-gel method. The synthesized powders were palletized and sintered at different temperatures starting from 500°C to 1000°C. XRD patterns of these samples confirm their single phase cubic spinel structure. The particle sizes obtained from XRD patterns using Debye-Scherrer formula were found to be in the range of 42 to 57 nm with almost a linear relationship between sintering temperature and particle size. Magnetization in these samples as a function of applied magnetic field was measured using vibrating sample magnetometer (VSM) and properties such as saturation magnetization (Ms) and coercivity (Hc) were found from M-H loops. It is found that Ms increases with increasing sintering temperature whereas Hc decreases. These variations in saturation magnetization and coercivity with sintering temperature are attributed to the corresponding variation in particle sizes.

  13. Single crystal growth and enhancing effect of glycine on characteristic properties of bis-thiourea zinc acetate crystal

    NASA Astrophysics Data System (ADS)

    Anis, Mohd; Muley, G. G.

    2016-08-01

    A single crystal of glycine-doped bis-thiourea zinc acetate (G-BTZA) with a dimension of 15 × 6 × 4 mm3 has been grown using the slow solution evaporation technique. The structural parameters of the crystals were determined using the single crystal XRD technique. The increase in optical transparency of the doped BTZA crystal was ascertained in the range of 200 to 900 nm using UV–visible spectral analysis. The improved optical band gap of the G-BTZA crystal is found to be 4.19 eV, and vital optical constants have been calculated using the transmittance data. The influence of glycine on the mechanical parameters of the BTZA crystal has been investigated via microhardness studies. The thermal stability of pure and doped BTZA crystals has been determined by employing the thermogravimetric and differential thermal analysis technique. The improvement in the dielectric properties of the BTZA crystal after the addition of glycine has been evaluated in a temperature range of 30 to 120 °C at a frequency of 100 KHz. The SHG efficiency of the glycine-doped BTZA crystal is found to be much higher than KDP and BTZA crystal material in a Kurtz–Perry powder analysis.

  14. Effect of Sputtering Gas environments on the Properties of Aluminum-doped Zinc Oxide Thin Films for Photovoltaic Application

    SciTech Connect

    Chauhan, Ram Narayan; Kumar, Jitendra; Singh, C.; Anand, R. S.

    2011-10-20

    Aluminum-doped zinc oxide thin films have been deposited on glass substrates by R.F. sputtering using ZnO(98%)-Al{sub 2}O{sub 3}(2%) target in different sputtering gaseous environments, viz., Ar, Ar/O{sub 2} and Ar/N{sub 2}+H{sub 2} at 80 deg. C. These films have been studied with regard to phase, microstructure, optical absorption and sheet resistance for application in photovoltaic devices as transparent conducting electrodes. The properties of the films are shown to strongly depend on the sputtering gas(es). The films exhibit a wurtzite-type hexagonal structure with the (00.2) preferred orientation, the c-axis perpendicular to the substrate. The intensity of 00.2 diffraction peak and the average crystallite size remain almost the same when the films are prepared under pure Ar or Ar/O{sub 2} environment. However the average crystallite size increases while electrical resistance decreases with introduction of nitrogen and hydrogen in comparison to oxygen in argon. Nevertheless, the optimum value of optical transmittance and sheet resistance of the films deposited in pure argon are found to be 85-96% in the wavelength range 400-800 nm and 65 {Omega}/{open_square}, respectively.

  15. A conformationally stressed novel ball-type perylenediimide appended zinc(II)phthalocyanine hybrid: spectroelectrochemical, electrocolorimetric and photovoltaic properties.

    PubMed

    Pekdemir, Fatih; Kurnalı, Sertan; Şengül, Abdurrahman; Altındal, Ahmet; Rıza Özkaya, Ali; Salih, Bekir; Bekaroğlu, Özer

    2015-01-01

    A supramolecule, 6, based on an electron-donor zinc phthalocyanine (ZnPc) and an electron-acceptor perylene diimide (PDI) has been synthesized and characterized by elemental analysis, UV/Vis, IR, (1)H NMR and solid state (13)C CPMAS NMR and also MALDI-TOF and ICP mass spectrometry. The PDI appended ZnPc core brings about a geometrical constraint in the molecule with intriguing spectroscopic, electrochemical and photovoltaic properties. The first reduction process of 6 occurs on the PDI core while the first oxidation takes place on the Pc ring. These processes reflect a considerably small HOMO-LUMO gap of 1.50 eV, which has vital importance for optoelectronic applications. In addition, the PDI-based first and second reduction processes of 6 are accompanied by an electrochromic behaviour with colour changes from dark purple to blue and blue to turquoise, respectively. A photovoltaic cell involving 6 as the donor and [6,6]-phenyl C61 butyric acid methyl ester as the acceptor has been fabricated. The measurements of the effect of annealing temperature on its performance indicated that the annealing process gives rise to a significant increase in the open circuit voltage, the fill factor and the photoconversion efficiency. PMID:25361438

  16. Synthesis, structural, topographical, linear and nonlinear optical, electrical and mechanical properties of Bisthiourea zinc acetate single crystal

    NASA Astrophysics Data System (ADS)

    Rajendran, V.; Uma, J.

    2016-07-01

    Nonlinear optical material Bisthiourea Zinc Acetate (BTZA) was synthesized by slow evaporation solution growth technique. The grown crystals were characterised by Single crystal XRD and powder XRD studies. The presence of functional groups and the co-ordination of metal ions to Thiourea were confirmed by FTIR analysis. The UV-vis -NIR spectrum shows a low absorption in the entire visible and IR region. Optical band gap of the grown crystal was found to be 4.18 eV. The photoluminescence studies carried out and the crystal has blue emission. The Refractive Index was determined experimentally for the first time and found to be 1.508 for the incident wavelength of 632.8 nm. The second harmonic generation efficiency was determined using Kurtz and Perry powder technique and it was 0.7 times than that of the KDP crystal. Thermal properties were studied by thermo gravimetric analysis and differential thermal analysis. Dielectric studies were carried out at different frequencies for various temperatures. The mechanical behaviour of the grown crystal was studied using Vickers micro hardness tester. The growth mechanism and surface features are investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM).

  17. Effect of interaction with micelles on the excited-state optical properties of zinc porphyrins and J-aggregates formation

    NASA Astrophysics Data System (ADS)

    Gonçalves, P. J.; Corrêa, D. S.; Franzen, P. L.; De Boni, L.; Almeida, L. M.; Mendonça, C. R.; Borissevitch, I. E.; Zílio, S. C.

    2013-08-01

    This work reports on the photophysical properties of zinc porphyrins meso-tetrakis methylpyridiniumyl (Zn2+TMPyP) and meso-tetrakis sulfonatophenyl (Zn2+TPPS) in homogeneous aqueous solutions and in the presence of sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonium bromide (CTAB) micelles. The excited-state dynamic was investigated with the Z-scan technique, UV-Vis absorption, and fluorescence spectroscopy. Photophysical parameters were obtained by analyzing the experimental data with a conventional five-energy-level diagram. The interaction of the charged side porphyrin groups with oppositely charged surfactants can reduce the electrostatic repulsion between porphyrin molecules leading to aggregation, which affected the porphyrin characteristics such as absorption cross-sections, lifetimes and quantum yields. The interaction between anionic ZnTPPS with cationic CTAB micelles induced the formation of porphyrin J-aggregates, while this effect was not observed in the interaction of ZnTMPyP with SDS micelles. This difference is, probably, due to the difference in electrostatic repulsion between the porphyrin molecules. The insights obtained by these results are important for the understanding of the photophysical behavior of porphyrins, regarding potential applications in pharmacokinetics as encapsulation of photosensitizer for drug delivery systems and in its interaction with cellular membrane.

  18. A conformationally stressed novel ball-type perylenediimide appended zinc(II)phthalocyanine hybrid: spectroelectrochemical, electrocolorimetric and photovoltaic properties.

    PubMed

    Pekdemir, Fatih; Kurnalı, Sertan; Şengül, Abdurrahman; Altındal, Ahmet; Rıza Özkaya, Ali; Salih, Bekir; Bekaroğlu, Özer

    2015-01-01

    A supramolecule, 6, based on an electron-donor zinc phthalocyanine (ZnPc) and an electron-acceptor perylene diimide (PDI) has been synthesized and characterized by elemental analysis, UV/Vis, IR, (1)H NMR and solid state (13)C CPMAS NMR and also MALDI-TOF and ICP mass spectrometry. The PDI appended ZnPc core brings about a geometrical constraint in the molecule with intriguing spectroscopic, electrochemical and photovoltaic properties. The first reduction process of 6 occurs on the PDI core while the first oxidation takes place on the Pc ring. These processes reflect a considerably small HOMO-LUMO gap of 1.50 eV, which has vital importance for optoelectronic applications. In addition, the PDI-based first and second reduction processes of 6 are accompanied by an electrochromic behaviour with colour changes from dark purple to blue and blue to turquoise, respectively. A photovoltaic cell involving 6 as the donor and [6,6]-phenyl C61 butyric acid methyl ester as the acceptor has been fabricated. The measurements of the effect of annealing temperature on its performance indicated that the annealing process gives rise to a significant increase in the open circuit voltage, the fill factor and the photoconversion efficiency.

  19. 46 CFR 148.330 - Zinc ashes; zinc dross; zinc residues; zinc skimmings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Zinc ashes; zinc dross; zinc residues; zinc skimmings... Materials § 148.330 Zinc ashes; zinc dross; zinc residues; zinc skimmings. (a) The shipper must inform the cognizant Coast Guard Captain of the Port in advance of any cargo transfer operations involving zinc...

  20. 46 CFR 148.330 - Zinc ashes; zinc dross; zinc residues; zinc skimmings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Zinc ashes; zinc dross; zinc residues; zinc skimmings... Materials § 148.330 Zinc ashes; zinc dross; zinc residues; zinc skimmings. (a) The shipper must inform the cognizant Coast Guard Captain of the Port in advance of any cargo transfer operations involving zinc...

  1. 46 CFR 148.330 - Zinc ashes; zinc dross; zinc residues; zinc skimmings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Zinc ashes; zinc dross; zinc residues; zinc skimmings... Materials § 148.330 Zinc ashes; zinc dross; zinc residues; zinc skimmings. (a) The shipper must inform the cognizant Coast Guard Captain of the Port in advance of any cargo transfer operations involving zinc...

  2. Zinc movement in sewage-sludge-treated soils as influenced by soil properties, irrigation water quality, and soil moisture level

    USGS Publications Warehouse

    Welch, J.E.; Lund, L.J.

    1989-01-01

    A soil column study was conducted to assess the movement of Zn in sewage-sludge-amended soils. Varables investigated were soil properties, irrigation water quality, and soil moisture level. Bulk samples of the surface layer of six soil series were packed into columns, 10.2 cm in diameter and 110 cm in length. An anaerobically digested municipal sewage sludge was incorporated into the top 20 cm of each column at a rate of 300 mg ha-1. The columns were maintained at moisture levels of saturation and unsaturation and were leached with two waters of different quality. At the termination of leaching, the columns were cut open and the soil was sectioned and analyzed. Zinc movement was evaluated by mass balance accounting and correlation and regression analysis. Zinc movement in the unsaturated columns ranged from 3 to 30 cm, with a mean of 10 cm. The difference in irrigation water quality did not have an effect on Zn movement. Most of the Zn applied to the unsaturated columns remained in the sludge-amended soil layer (96.1 to 99.6%, with a mean of 98.1%). The major portion of Zn leached from the sludge-amended soil layer accumulated in the 0- to 3-cm depth (35.7 to 100%, with a mean of 73.6%). The mean final soil pH values decreased in the order: saturated columns = sludge-amended soil layer > untreated soils > unsaturated columns. Total Zn leached from the sludge-amended soil layer was correlated negatively at P = 0.001 with final pH (r = -0.85). Depth of Zn movement was correlated negatively at P = 0.001 with final pH (r = -0.91). Multiple linear regression analysis showed that the final pH accounted for 72% of the variation in the total amounts of Zn leached from the sludge-amended soil layer of the unsaturated columns and accounted for 82% of the variation in the depth of Zn movement among the unsaturated columns. A significant correlation was not found between Zn and organic carbon in soil solutions, but a negative correlation significant at P = 0.001 was found

  3. Structural properties and gas sensing behavior of sol-gel grown nanostructured zinc oxide

    NASA Astrophysics Data System (ADS)

    Rajyaguru, Bhargav; Gadani, Keval; Rathod, K. N.; Solanki, Sapana; Kansara, S. B.; Pandya, D. D.; Shah, N. A.; Solanki, P. S.

    2016-05-01

    In this communication, we report the results of the studies on structural properties and gas sensing behavior of nanostructured ZnO grown using acetone precursor based modified sol-gel technique. Final product of ZnO was sintered at different temperatures to vary the crystallite size while their structural properties have been studied using X-ray diffraction (XRD) measurement performed at room temperature. XRD results suggest the single phasic nature of all the samples and crystallite size increases from 11.53 to 20.96nm with increase in sintering temperature. Gas sensing behavior has been studied for acetone gas which indicates that lower sintered samples are more capable to sense the acetone gas and related mechanism has been discussed in the light of crystallite size, crystal boundary density, defect mechanism and possible chemical reaction between gas traces and various oxygen species.

  4. Carboxylated dithiafulvenes and tetrathiafulvalene vinylogues: synthesis, electronic properties, and complexation with zinc ions

    PubMed Central

    Wang, Yunfei

    2015-01-01

    Summary A class of carboxyl and carboxylate ester-substituted dithiafulvene (DTF) derivatives and tetrathiafulvalene vinylogues (TTFVs) has been synthesized and their electronic and electrochemical redox properties were characterized by UV–vis spectroscopic and cyclic voltammetric analyses. The carboxyl-TTFV was applied as a redox-active ligand to complex with Zn(II) ions, forming a stable Zn-TTFV coordination polymer. The structural, electrochemical, and thermal properties of the coordination polymer were investigated by infrared spectroscopy, cyclic voltammetry, powder X-ray diffraction, and differential scanning calorimetric analyses. Furthermore, the microscopic porosity and surface area of the Zn-TTFV coordination polymer were measured by nitrogen gas adsorption analysis, showing a BET surface of 148.2 m2 g−1 and an average pore diameter of 10.2 nm. PMID:26124898

  5. Synthesis, Spectral Characterization, and Biochemical Evaluation of Antidiabetic Properties of a New Zinc-Diosmin Complex Studied in High Fat Diet Fed-Low Dose Streptozotocin Induced Experimental Type 2 Diabetes in Rats

    PubMed Central

    Gopalakrishnan, Veerasamy; Iyyam Pillai, Subramanian; Subramanian, Sorimuthu Pillai

    2015-01-01

    In view of the established antidiabetic properties of zinc, the present study was aimed at evaluating the hypoglycemic properties of a new zinc-diosmin complex in high fat diet fed-low dose streptozotocin induced experimental type 2 diabetes in rats. Zinc-diosmin complex was synthesized and characterized by various spectral studies. The complexation between zinc ions and diosmin was further evidenced by pH-potentiometric titrations and Job's plot. Diabetic rats were orally treated with zinc-diosmin complex at a concentration of 20 mg/kg b.w./rat/day for 30 days. At the end of the experimental period, the rats were subjected to oral glucose tolerance test. In addition, HOMA-IR and various biochemical parameters related to glucose homeostasis were analyzed. Treatment with zinc-diosmin complex significantly improved the glucose homeostasis in diabetic rats. Treatment with zinc-diosmin complex significantly improved insulin sensitivity, at least in part, through enhancing protein metabolism and alteration in the levels of muscle and liver glycogen. The assay of clinical marker enzymes revealed the nontoxic nature of the complex. Determination of renal tissue markers such as blood urea and serum creatinine indicates the renoprotective nature of the complex. These findings suggest that zinc-diosmin complex is nontoxic and has complimentary potential to develop as an antihyperglycemic agent for the treatment of diabetes mellitus. PMID:26783461

  6. Investigation of spectroscopic properties, structure and luminescence spectra of Sm3+ doped zinc bismuth silicate glasses.

    PubMed

    Pal, I; Agarwal, A; Sanghi, S; Aggarwal, M P

    2013-01-15

    The glasses with compositions 20ZnO·(79.5-x)Bi2O3·xSiO2·0.5Sm2O3 (10≤x≤50, mol%) have been synthesized using normal melt-quench technique. Optical absorption and fluorescence spectra of the glasses were recorded at ambient temperature. Judd-Ofelt (J-O) theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From the measured intensities of absorption bands of these glasses, the Judd-Ofelt parameters, Ωλ (λ=2, 4, 6) have been evaluated. The variation of Ω2 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth (RE) ion site (due to structural change) and to changes in RE-O covalency, whereas the variation of Ω6 is found to be strongly dependent on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the RE-O decreases with decrease in Bi2O3 content in the host glass. Also, using J-O theory various radiative properties like spontaneous emission probability (Arad), radiative life time (τr), fluorescence branching ratio (βr) and stimulated emission cross-section (σ) for various emission bands of these glasses in the visible spectral region have been determined. A close correlation is observed between the Bi2O3 content and the spectroscopic, radiative and structural properties of the prepared glasses. The values of radiative properties indicated that 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region.

  7. Microstructural and mechanical property evaluation of black chrome and zinc oxide coated solar collectors. Annual report No. II, June 1979-March 1980

    SciTech Connect

    Inal, O T

    1980-01-01

    Plating parameters for black-chrome system were optimized with respect to selectivity utilizing simplex evolutionary operation procedures in sixteen sets of experiments. Overgrowths produced with the optimized parameters were then evaluated for optical, structural, thermal stability and mechanical properties. It is observed that the coatings produced possess consistently high selectivity values (approx. 10), are durable against exposure to high temperature (> 400/sup 0/C in air and > 500/sup 0/C in neutral atmosphere), are well attached to their structure (> 340 kg/cm/sup 2/), and are quite ductile (bent to 131.5/sup 0/ previous to fracture) and reasonably remain so following exposure to 500/sup 0/C (2 hrs) in air (84.2% bend previous to fracture). Black zinc oxide surfaces created on leaf zinc, electroplated zinc on steel, and hot-dip zinc coated steel substrates show selectivity values that vary between 6-9, are seen to maintain their physical integrity as well as optical properties following exposure to 250/sup 0/C (2 hrs) in air, possess high strength of attachment to their substrates (> 285 kg/cm/sup 2/), and are quite ductile (170/sup 0/ bend previous to fracture) and maintain a reasonably high ductility (121/sup 0/ bend previous to fracture) following exposure to 250/sup 0/C (2 hrs) in air. Structural analysis of both overgrowths show them to consist of oxide particles within which elemental component of the oxide is seen to be distributed in the unassociated form. The plating parameters utilized in deposition of the coatings are seen to alter quantity and distribution of the elemental component and effect optical properties of these surfaces. These composite particles are seen to be of various sizes but the distribution of these particles are seen to be constant throughout the overgrowth.

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

    SciTech Connect

    Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming Xu, Bing; Wang, Bao-Cheng; Xie, Juan; Yuan, Fei; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

    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 a 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

  9. Magnetic properties of lithium zinc ferrites synthesized by microwave sintered method

    NASA Astrophysics Data System (ADS)

    Yang, Qinghui; Zhang, Huaiwu; Wen, Qiye; Liu, Yingli; Yang, Xuwen

    2016-05-01

    In this paper, a series of polycrystalline ferrite samples were prepared with the composition of Zn0.1Li0.525-xTi0.15MgxFe2.225-0.5xO4 (LiZn) (x=0, 0.05, 0.10, 0.15 and 0.20) using both microwave sintering (MS) and conventional sintering (CS) technologies, respectively. The sintering time and temperature were 22 hours and 1000°C for the CS process, and 2 hours and 880°C for the MS process. Experiments showed that the MS treated LiZn ferrites exhibited more excellent magnetic properties and denser, more uniform micro-structures comparing with the ones treated by CS method. For the LiZn ferrite (x=0.1) sintered at 880°C using MS, the saturation magnetic induction (Bs) is 242.3 mT, the coercive force (Hc) is 135 A/m, the square ratio (Br/Bs) is 0.87 and the ferromagnetic resonance line-width (Δ H) is 143.2 Oe. These results represented very good properties for an X-band phase shifter material and indicated that the MS method is a potentially important technique for fabricating low temperature co-fired ceramics (LTCC).

  10. Depleting depletion: Polymer swelling in poor solvent mixtures

    NASA Astrophysics Data System (ADS)

    Mukherji, Debashish; Marques, Carlos; Stuehn, Torsten; Kremer, Kurt

    A polymer collapses in a solvent when the solvent particles dislike monomers more than the repulsion between monomers. This leads to an effective attraction between monomers, also referred to as depletion induced attraction. This attraction is the key factor behind standard polymer collapse in poor solvents. Strikingly, even if a polymer exhibits poor solvent condition in two different solvents, it can also swell in mixtures of these two poor solvents. This collapse-swelling-collapse scenario is displayed by poly(methyl methacrylate) (PMMA) in aqueous alcohol. Using molecular dynamics simulations of a thermodynamically consistent generic model and theoretical arguments, we unveil the microscopic origin of this phenomenon. Our analysis suggests that a subtle interplay of the bulk solution properties and the local depletion forces reduces depletion effects, thus dictating polymer swelling in poor solvent mixtures.

  11. Optical and electrical properties of undoped and boron doped zinc oxide synthesized by chemical route

    SciTech Connect

    Bhattacharjee, Snigdha; Basu, Moumita; Roy, Asim

    2015-08-28

    We have synthesized and studied the boron doped ZnO nanostructure thin films. The crystallinity of undoped and boron (B) doped ZnO (BZO) has been studied from XRD results. Using the Debye-Scherrer Formula, the grain size has been evaluated, which was found to decrease with increased doping concentration. The optical and electrical properties of (1, 3, 5 wt%) B-doped ZnO (BZO) has been investigated with reference to the undoped counterpart. The UV-VIS spectroscopic analysis revealed that the transmittance for undoped ZnO is maximum and it decreases with doping up to 3% but increases for 5% BZO. The dark as well as photo current–voltage (I–V) characteristics have been investigated in details and the changes occurred in the I-V characteristics with doping concentration as well as under illumination are also quite significant.

  12. Electrical properties of films of zinc oxide nanoparticles and its hybrid with reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Madhuri, K. Priya; Bramhaiah, K.; John, Neena S.

    2016-05-01

    Free-standing films of ZnO nanoparticles (NPs) and reduced graphene oxide (rGO)-ZnO NPs hybrid are prepared at a liquid/liquid interface. The films are characterized by UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. ZnO film consists of spherical aggregated NPs while the hybrid film contains folded sheets of rGO with embedded ZnO NPs. Electrical properties of the films and its photoresponse in presence of UV radiation are investigated using current sensing atomic force microscopy (CSAFM) at nanoscale and bulk measurements using two probe methods. Enhancement in photocurrent is observed in both cases and the current imaging reveals an inhomogeneous contribution by different ZnO grains in the film.

  13. Structural and electronic properties of cubic boron nitride doped with zinc

    NASA Astrophysics Data System (ADS)

    Li, Yubo; Cheng, Tianyuan; Wang, Xiao; Jiang, Huaxing; Yang, Hangsheng; Nose, Kenji

    2014-07-01

    Structural and electronic properties of Zn-doped cubic boron nitride (cBN) were investigated via first principle calculation based on density functional theory. Our simulation suggests that Zn can substitute for both B (ZnB) and N (ZnN) atom; ZnB is energetically favorable, and ZnN can only be prepared under B-rich conditions. ZnB induced a shallow acceptor level; however, the large difference in electronegativity between Zn and N makes the acceptor level strongly localized, which reduces effective carrier density. In the case of ZnN, both deep acceptor levels within band gap and shallow acceptor levels at the top of valence band were induced, which produced more free carriers than ZnB. The calculated results account for experimental results of enhanced electric conductivity of Zn-doped cBN films prepared under B-rich conditions.

  14. Structural and electronic properties of cubic boron nitride doped with zinc

    SciTech Connect

    Li, Yubo; Cheng, Tianyuan; Wang, Xiao; Jiang, Huaxing; Yang, Hangsheng; Nose, Kenji

    2014-07-28

    Structural and electronic properties of Zn-doped cubic boron nitride (cBN) were investigated via first principle calculation based on density functional theory. Our simulation suggests that Zn can substitute for both B (Zn{sub B}) and N (Zn{sub N}) atom; Zn{sub B} is energetically favorable, and Zn{sub N} can only be prepared under B-rich conditions. Zn{sub B} induced a shallow acceptor level; however, the large difference in electronegativity between Zn and N makes the acceptor level strongly localized, which reduces effective carrier density. In the case of Zn{sub N}, both deep acceptor levels within band gap and shallow acceptor levels at the top of valence band were induced, which produced more free carriers than Zn{sub B}. The calculated results account for experimental results of enhanced electric conductivity of Zn-doped cBN films prepared under B-rich conditions.

  15. Fabrication and magnetic property analysis of monodisperse manganese-zinc ferrite nanospheres

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Zhu, Meifang; Zhang, Qinghong; Li, Yaogang; Wang, Hongzhi

    2009-10-01

    Monodisperse Mn-Zn ferrite (Mn 1-xZn xFe 2O 4) nanospheres have been prepared via a simple solvothermal method. The as-synthesized samples were characterized in detail by X-ray diffraction pattern (XRD), transmission electron microscope (TEM), high-solution transmission electron microscope (HRTEM), select area electron diffraction pattern (SAED), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM). The results show that a large number of the high-purity Mn 1-xZn xFe 2O 4 nanocrystallites were synthesized and these nanocrystallites oriented aggregated to nanospheres. The dependence of magnetic properties of Mn 1-xZn xFe 2O 4 nanospheres on the composition content x of Zn was studied. The maximum saturation magnetization value of the as-prepared sample (Mn 0.6Zn 0.4Fe 2O 4) reached 52.4 emu g -1.

  16. Synthesis, growth kinetics and optical properties of zinc oxide nanoparticle suspensions and thin films

    NASA Astrophysics Data System (ADS)

    Wong, Eva May

    2000-10-01

    Colloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. The growth kinetics of the ZnO particles were found to follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films of ZnO quantum particles were fabricated by electrophoretic deposition from suspensions prepared via a colloidal chemistry synthesis route. Films were prepared at constant current thus eliminating the limited deposition rate associated with constant voltage deposition. The kinetics for the deposition of thin films were determined using optical absorbance techniques in conjunction with atomic absorption spectrometry. The particle velocity during deposition and the charge on the particles were determined from the deposition kinetics. The thin films prepared by electrophoretic deposition exhibited optical properties characteristic of the quantum size particles. The average particle size, and hence the optical properties, were tailored by controlling the aging time and temperature of the suspensions. Both the band-to-band and visible photoluminescence were progressively blue shifted, relative to the bulk value, with decreasing particle size in the film. A linear dependence was found between the band-to-band and visible emission. Finally, particle growth was manipulated by the specific adsorption of a series of capping ligands at the particle surface. The adsorption of the capping ligands was found to produce a diffusion barrier such that particle growth was stunted following incorporation with the extent of this effect being dependent

  17. Some properties of an alcohol dehydrogenase partially purified from baker's yeast grown without added zinc.

    PubMed Central

    Dickenson, C J; Dickinson, F M

    1976-01-01

    Alcohol dehydrogenase was partially purified from yeast (Saccharomyces cerevisiae) grown in the presence of 20 muM-MnSO4 without added Zn2+ and from yeast grown in the presence of 1.8 muM-MnSO4. The enzyme from yeast grown with added Zn2+ has the same properties as the crystalline enzyme from commercial supplies of baker's yeast. The enzyme from yeast grown without added An2+ has quite different properties. It has a mol.wt. in the region of 72000 and an S 20 w of 5.8S. The values can be compared with a mol.wt. of 141000 and an S 20 w of 7.6S for the crystalline enzyme. ADP-ribose, a common impurity in commercial samples of NAD+, is a potent competitive inhibitor of the new enzyme (K1 = 0.5 muM), but is not so for the crystalline enzyme. The observed maximum rate of ethanol oxidation at pH 7.05 and 25 degrees C was decreased 12-fold by the presence of 0.06 mol of inhibitor/mol of NAD+ when using the enzyme from Zn2+-deficient yeast, but with crystalline enzyme the maximum rate was essentially unchanged by this concentration of inhibitor. The kinetic characteristics for the two enzymes with ethanol, butan-1-ol, acetaldehyde and butyraldehyde as substrates are markedly different. These kinetic differences are discussed in relation to the mechanism of catalysis for the enzyme from Zn2+-deficient yeast. PMID:179534

  18. Combinatorial Insights into Doping Control and Transport Properties of Zinc Tin Nitride

    SciTech Connect

    Fioretti, Angela N.; Zakutayev, Andriy; Moutinho, Helio; Melamed, Celeste; Perkins, John D.; Norman, Andrew G.; Al-Jassim, Mowafak; Toberer, Eric S.; Tamboli, Adele C.

    2015-09-21

    ZnSnN2 is an Earth-abundant semiconductor analogous to the III–nitrides with potential as a solar absorber due to its direct bandgap, steep absorption onset, and disorder-driven bandgap tunability. Despite these desirable properties, discrepancies in the fundamental bandgap and degenerate n-type carrier density have been prevalent issues in the limited amount of literature available on this material. We we use a combinatorial RF co-sputtering approach, we explored a growth-temperature-composition space for Zn1+xSn1-xN2 over the ranges 35–340 °C and 0.30–0.75 Zn/(Zn + Sn). In this way, we identified an optimal set of deposition parameters for obtaining as-deposited films with wurtzite crystal structure and carrier density as low as 1.8 × 1018 cm-3. Films grown at 230 °C with Zn/(Zn + Sn) = 0.60 were found to have the largest grain size overall (70 nm diameter on average) while also exhibiting low carrier density (3 × 1018 cm-3) and high mobility (8.3 cm2 V-1 s-1). Using this approach, we establish the direct bandgap of cation-disordered ZnSnN2 at 1.0 eV. Moreover, we report tunable carrier density as a function of cation composition, in which lower carrier density is observed for higher Zn content. Consequently, this relationship manifests as a Burstein–Moss shift widening the apparent bandgap as cation composition moves away from Zn-rich. Collectively, these findings provide important insight into the fundamental properties of the Zn–Sn–N material system and highlight the potential to utilize ZnSnN2 for photovoltaics.

  19. Oxygen partial pressure dependent magnetic properties of manganese-zinc ferrite polycrystals

    SciTech Connect

    Byeon, S.C.; Hong, K.S.; Je, H.J.

    1997-05-01

    A systematic variation in initial permeability with oxygen partial pressure during post sintering cooling was observed in Mn{sub 0.47}Zn{sub 0.47}Fe{sub 2.06}O{sub 4} polycrystalline samples. The initial permeability increased from 6,300 to 8,600 when the atmospheric parameter decreased from 8.4 to 6.4. Here atmospheric parameter is the degree of oxygen partial pressure engaged in the cooling stage of the sample preparation. The origins of this systematic variation were investigated by measuring the saturation magnetization under high fields (10 kOe) and by observing microstructure changes as well as the magnetic properties under small applied fields (0.15 mOe). It was found that saturation magnetization of samples under high fields was almost unchanged in the range of oxygen partial pressures through which Fe{sup 2+} concentration varied by up to 0.5%. The systematic changes in saturated magnetization and saturation time under small applied fields suggest that the permeability is strongly dependent on domain mobility. This increase in domain mobility was attributed to increased grain growth with decreasing oxygen partial pressure.

  20. Evaluation of the piezoelectric properties and voltage generation of flexible zinc oxide thin films.

    PubMed

    Laurenti, M; Stassi, S; Lorenzoni, M; Fontana, M; Canavese, G; Cauda, V; Pirri, C F

    2015-05-29

    Local piezoresponse and piezoelectric output voltage were evaluated on ZnO thin films deposited by radio-frequency magnetron sputtering on hard Si/Ti/Au and flexible Cu-coated polyimide substrates. Three different thicknesses of ZnO films were studied (285 nm, 710 nm, and 1380 nm), focusing on characteristics like crystallinity, grain size, surface roughness, and morphology. Independent of the nature of the metal layer and the substrate, our results show that thicker films presented a higher level of crystallinity and a preferential orientation along the c-axis direction, as well as a lower density of grain boundaries and larger crystal sizes. The improvement of the crystalline structure of the material directly enhances its piezoelectric properties, as confirmed by the local characterizations performed by piezoresponse force microscopy and by the evaluation of the output voltage generation under the application of a periodical mechanical deformation on the whole film. In particular, the highest value of the d33 coefficient obtained (8 pm V(-1)) and the highest generated output voltage (0.746 V) belong to the thickest films on hard and flexible substrates, respectively. These results envision the use of ZnO thin films--particularly on flexible substrates--as conformable, reliable, and efficient active materials for use in nanosensing, actuation, and piezoelectric nanogenerators.

  1. Structural, optical and electrical properties of cadmium zinc oxide films for light emitting devices

    NASA Astrophysics Data System (ADS)

    Sonawane, B. K.; Shelke, Vrushali; Bhole, M. P.; Patil, D. S.

    2011-12-01

    Structural, optical and electrical properties of CdyZn1-yO (y=0-0.1) ternary alloy thin films have been investigated for the films prepared using the spin coating method on the glass substrate. XRD pattern confirmed the nano-size polycrystalline hexagonal wurtzite structure for all the samples. The size of nano-crystals was found to be varied in between 21 and 30 nm. Optical band gap calculated from the absorption coefficient signifies the shift in direct band gap from 3.2 to 2.97 eV with cadmium composition. Through EDAX spectrum, it was confirmed that Cadmium was successfully incorporated into ZnO. SEM studies make clear that even after Cadmium incorporation, the surface morphology of the films remained smooth. The current-voltage characteristics obtained from semiconductor characterization system reveals that resistance of the films was found to be decreased with the increase in cadmium composition. Our investigations lead to the applicability of CdZnO as an active layer in CdZnO/ZnO heterostructure for light emitting devices.

  2. Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

    NASA Astrophysics Data System (ADS)

    Yasakau, K. A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M. G. S.; Zheludkevich, M. L.

    2016-12-01

    In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

  3. Structural and optical properties of chromium doped zinc oxide nanoparticles synthesized by sol-gel method

    SciTech Connect

    Naqvi, Syed Mohd. Adnan; Irshad, Kashif; Soleimani, Hassan E-mail: noorhana-yahya@petronas.com.my; Yahya, Noorhana E-mail: noorhana-yahya@petronas.com.my

    2014-10-24

    Nanosized Cr-doped ZnO nano particles were synthesized by facile sol-gel auto combustion method. The structural and optical properties of Cr-doped ZnO nanoparticles have been investigated by XRD and UV-Vis spectroscopy at room temperature for 0% to 8% concentration. X-ray diffraction analysis reveals that the Cr-doped ZnO crystallizes in a single phase polycrystalline nature with wurtzite lattice. With every % of doping, the peaks are shifting scarcely and doping of Cr is possible up to 7%. After that, the last peak vanishes, that signifies its structure is transmuted from 8% doping. The average crystallite size decreases with increase in Cr concentration (i.e. 28.9 nm for 0% to 25.8 nm for 8%). The UV-Vis spectra of the nanoparticles betoken an incrementation in the band gap energy from 3.401, 3.415, 3.431, 3.437,3.453, 3.514,3.521, 3.530 and 3.538 eV respectively, for 0,1, 2, 3, 4, 5, 6, 7 and 8 % doping concentration.

  4. Effect of Mo substitution on structural and magnetic properties of Zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Heiba, Zein K.; Mohamed, Mohamed Bakr; Wahba, Adel Maher

    2016-03-01

    Nano ferrite ZnFe2-xMoxO4 (x = 0.0, 0.1, 0.2, and 0.3) samples were synthesized by using citrate method. The phase purity and the structure parameters were studied using X-ray diffraction, FT-IR spectroscopy, and magnetic measurements. Rietveld analysis of X-ray diffraction data revealed that Mo doping ZnFe2O4 changes the degree of inversion of Zn2+ cations. The oxidation state of Mo was studied by using FTIR analysis. Mo doped ZnFe2O4 has a ferromagnetic properties. The magnetization decreases by the replacement of Fe3+ ions by non-magnetic Mo3+ ions. Mo doped ZnFe2O4 samples have a very small coercive field (Hc), which changes depending on the amount of Mo in the sample and reach its maximum value for ZnFe1.7Mo0.3O4. Cation distribution is proposed in an attempt to explain the experimental results of XRD, IR, and VSM data. The direct proportion between the coercive field and the Fe2+ content in the samples was studied in detailed.

  5. Effect of F ions on physical and optical properties of fluorine substituted zinc arsenic tellurite glasses

    NASA Astrophysics Data System (ADS)

    Kareem Ahmmad, Shaik; kondaul, Edu; Rahman, Syed

    2015-02-01

    The effect of substitution of fluoride ions for oxide ions on the physical and optical properties of glass system (20-x) ZnO-xZnF2-40As2O3-40TeO2 where x = 0, 4, 8,12,16,20 mole % were investigated. The samples prepared by melt quenching method under controlled condition. The amorphous nature of these glasses was checked by X-ray diffraction technique. The density was measured according to Archimedes principle. The room temperature absorption spectra of all glass samples were determined using UV-Vis-NIR spectrometer. The thermal behaviour, glass transition temperature and stability of glass samples were studied by a differential scanning calorimetric (DSC). The density reduction of present glasses with ZnF2 concentrations may be due to the low density of ZnF2 compared with that of ZnO. Breaking the oxide network, the cross linking degree of the glass former could be reduced which results in decrease of both Tg and Tx. In the present glass system when F ions replaced by oxygen ions UV-Vis absorption cut-off wavelength decreases. This resulted form the conversion of structural unit in the glass from TeO4 to Te(O,F)4 and then to Te(O, F)3.

  6. Microscopic structure and electrical transport property of sputter-deposited amorphous indium-gallium-zinc oxide semiconductor films

    NASA Astrophysics Data System (ADS)

    Yabuta, H.; Kaji, N.; Shimada, M.; Aiba, T.; Takada, K.; Omura, H.; Mukaide, T.; Hirosawa, I.; Koganezawa, T.; Kumomi, H.

    2014-06-01

    We report on microscopic structures and electrical and optical properties of sputter-deposited amorphous indium-gallium-zinc oxide (a-IGZO) films. From electron microscopy observations and an x-ray small angle scattering analysis, it has been confirmed that the sputtered a-IGZO films consist of a columnar structure. However, krypton gas adsorption measurement revealed that boundaries of the columnar grains are not open-pores. The conductivity of the sputter-deposited a-IGZO films shows a change as large as seven orders of magnitude depending on post-annealing atmosphere; it is increased by N2-annealing and decreased by O2-annealing reversibly, at a temperature as low as 300°C. This large variation in conductivity is attributed to thermionic emission of carrier electrons through potential barriers at the grain boundaries, because temperature dependences of the carrier density and the Hall mobility exhibit thermal activation behaviours. The optical band-gap energy of the a-IGZO films changes between before and after annealing, but is independent of the annealing atmosphere, in contrast to the noticeable dependence of conductivity described above. For exploring other possibilities of a-IGZO, we formed multilayer films with an artificial periodic lattice structure consisting of amorphous InO, GaO, and ZnO layers, as an imitation of the layer-structured InGaZnO4 homologous phase. The hall mobility of the multilayer films was almost constant for thicknesses of the constituent layer between 1 and 6 Å, suggesting rather small contribution of lateral two-dimensional conduction It increased with increasing the thickness in the range from 6 to 15 Å, perhaps owing to an enhancement of two-dimensional conduction in InO layers.

  7. Photo- and electroluminescent properties of zinc(II) complexes with tetradentate Schiff bases, derivatives of salicylic aldehyde

    NASA Astrophysics Data System (ADS)

    Vashchenko, A. A.; Lepnev, L. S.; Vitukhnovskii, A. G.; Kotova, O. V.; Eliseeva, S. V.; Kuz'mina, N. P.

    2010-03-01

    It is studied how the introduction of various substituents into the composition of organic ligands affects the photoluminescence spectra of new zinc(II) complexes with tetradentate Schiff bases H2L (derivatives of salicylic aldehyde (H2SAL1, H2SAL2) and o-vanillin (H2MO1, H2MO2) with ethylenediamine and o-phenylenediamine) in the form of bulk solids and thin films. It is demonstrated that the emission spectra of bulk solid complexes without o-phenylenediamine bridges (ZnSAL1 and ZnMO1) contain additional long-wavelength bands compared to the spectra of corresponding thin films. In the case of films obtained from [ZnSAL1]2 dimer complexes, the long-wavelength band is dominant. At the same time, the photoluminescence spectra of ZnSAL2 and ZnMO2 complexes with o-phenylenediamine bridges are similar in the case of solid samples and thin films. The electroluminescent properties of organic light-emitting diodes (OLEDs) with the ITO/α-NPD/ZnL/Ca:Al structure are studied. The bathochromic shift of the electroluminescence peaks of OLEDs with respect to the photoluminescence spectra of bulk solid samples and thin films is probably related to the formation of exciplexes at the α-NPD/ZnL interface. The electroluminescence spectra of OLEDs based on [ZnSAL1]2 show a hypsochromic shift of the emission maximum, which can be caused by a shift of the recombination region into the α-NPD layer.

  8. Impact of thin metal layer on the optical and electrical properties of indium-doped-tin oxide and aluminum-doped-zinc oxide layers

    NASA Astrophysics Data System (ADS)

    Kumar, Melvin David; Park, Yun Chang; Kim, Joondong

    2015-06-01

    The distinguished transparent conductive oxide (TCO) layers like indium-doped-tin oxide (ITO) and aluminum-doped-zinc oxide (AZO) layers were prepared in different combinations with and without thin Ni metal layer. The optical and electrical properties of prepared samples were analyzed and compared with the objective to understand the role and influence of the Ni layer in each TCO combination. The highest transmittance value of 91.49% was exhibited by prepared AZO layers. Even though if the transmittance of Ni inserting TCO layers was marginally reduced than that of the ordinary TCO samples, they exhibited balanced optical properties with enhanced electrical properties. Carrier concentration of indium doped tin-oxide and aluminum doped zinc oxide (ITO/AZO) bilayer sample is increased more than double the times when the Ni layer was inserted between ITO and AZO. Thin layer of Ni in between TCO layers reduced sheet resistance and offered substantial transmittance, so that the figure of merit (FOM) value of Ni embedding TCOs was greater than that of TCOs without Ni layer. The ITO/Ni/AZO combination provided optimum results in all the electrical properties. As compared to other TCO/metal combinations, the overall performance of ITO/Ni/AZO tri-layer combination was appreciable. These results show that the optical and electrical properties of TCO layers could be enhanced by inserting a Ni layer with optimum thickness in between them.

  9. Do thickening properties of locust bean gum affect the amount of calcium, iron and zinc available for absorption from infant formula? In vitro studies.

    PubMed

    Bosscher, D; Van Caillie-Bertrand, M; Deelstra, H

    2003-07-01

    Locust bean gum acts as a milk thickener in infant formula because of its high apparent viscosity. The effects of such thickening agents on metabolic and physiologic responses during infancy have not been clarified sufficiently. Due to the increased volume of the digest and the bulking and trapping effects, digestion and absorption of nutrients may be influenced in presence of locust bean gum. The central question addressed in this paper is whether the thickening properties of locust bean gum affect the availability of calcium, iron, and zinc. Increasing amounts of powdered locust bean gum were homogenised with infant formula and samples were diluted to 0.14, 0.27, 0.42 and 0.71 g/100 ml. Viscosity of the samples was measured by a Carrie-Med CSL100 rheometer. Available amounts of calcium, iron, and zinc were evaluated using a continuous-flow dialysis model with preliminary digestion. Elemental contents of samples and dialysates were analysed with atomic absorption spectrometry. The first set of experiments showed that addition of locust bean gum to infant formulas increased the viscosity of the luminal contents. Correlations between the locust bean gum concentration and the viscosity of the samples before and after gastric or intestinal digestion were highly significant (0.97). In the second set of experiments, the correlations between the locust bean gum concentration and the amounts of calcium trapped by the locust bean gum fraction also showed high significance (0.93). In the third experimental design, again strong correlations were found between the viscosity of the intestinal digest and the amounts of calcium trapped by the fibre fraction (0.90). For iron and zinc, no such relationships were found. From this experimental set-up it appears that locust bean gum influences calcium availability in infant formulas by means of its physical properties to act as thickening agent, rather than its chemical ability to form complexes as demonstrated earlier with respect

  10. Photophysical properties of CdSe quantum dot self-assemblies with zinc phthalocyanines and azaphthalocyanines.

    PubMed

    Suchánek, Jan; Lang, Kamil; Novakova, Veronika; Zimcik, Petr; Zelinger, Zdeněk; Kubát, Pavel

    2013-05-01

    The formation of self-assemblies between CdSe quantum dots (QDs) and Zn phthalocyanines (Pc) and azaphthalocyanines (AzaPc) bearing alkylsulfanyl substituents and the photophysical properties of these assemblies were studied using both steady-state and time-resolved luminescence/absorption spectroscopy. The formation of the self-assemblies was accompanied by a blue shift of the Q band of the dyes and by a quenching of the CdSe QDs luminescence. The largest spectral shift of the Q-band was approximately 7 nm and was observed for pentan-3-ylsulfanyl-functionalised phthalocyanine (). Assuming a 1 : 1 stoichiometry, the calculated binding constant was 4 × 10(4) M(-1). Pc substituted with the bulky tert-butylsulfanyl groups (1) exhibited a smaller shift of the Q band. The quenching of the CdSe QDs luminescence by 1 was more effective than that observed for 3. The results indicated that the luminescence quenching may be due to a photoinduced charge transfer between 1 or 3 and the CdSe QDs. In contrast, the AzaPc (2) with the same substituents as 1 had little effect on the QDs luminescence. For all cases, we found an inefficient resonance energy transfer between the attached dyes and the CdSe QD. The formation of the self-assemblies had negligible effects on the photogeneration of the singlet oxygen, O2((1)Δg), that was fully controlled only by the absorption of the light by the macrocycles.

  11. Thermal and electrical properties of zinc oxide nanowires embedded in silica aerogel

    NASA Astrophysics Data System (ADS)

    Xie, Jing

    Thermoelectric materials that can convert heat to electricity are good candidates for energy sources considering that the majority of energy produced in the world is wasted as heat. The performance of a thermoelectric material is characterized by the thermoelectric figure of merit, ZT= S 2σT/κ, where κ, T, σ and S are, respectively, the thermal conductivity, temperature, electrical conductivity and Seebeck coefficient. To improve the efficiency of energy conversion with thermoelectric materials, large values of ZT are required. The major obstacle to this is attempting to increase σ and S while decreasing κ since these quantities are interrelated and cannot, generally, be controlled independently. We propose a nanocomposite of ZnO nanowires embedded in silica aerogel to solve this problem. The silica aerogel was used as a lattice vibration cladding layer, providing a new path for heat carrying phonons scattered from the nanowire surface, which should decrease the lattice thermal conductivity without compromising the electrical performance of ZnO nanowires. Our experimental results demonstrated that the thermal conductivity of ZnO nanowire arrays was greatly reduced by adding silica aerogel as a cladding layer. In order to control the morphology and density of ZnO nanowire arrays, the growth mechanism of ZnO nanowires was investigated. We thoroughly investigated the thermal and electrical properties of ZnO nanowire arrays. The measured thermal conductivities of ZnO nanowires and bulk ZnO indicate that boundary scattering is the dominant phonon scattering mechanism in this material. The electrical conductivity in Cr-ZnO Nanowire-Cr metal-semiconductor-metal structures was found to be determined by the reverse biased Schottky barriers present at the Cr/ZnO interface. This transport mechanism was not affected by the presence of N2 or air. Pressure was found to play an important role in the current-voltage characteristics of these nanowires due to the piezoelectric

  12. Effects of annealing conditions on the dielectric properties of solution-processed Al2O3 layers for indium-zinc-tin-oxide thin-film transistors.

    PubMed

    Kim, Yong-Hoon; Kim, Kwang-Ho; Park, Sung Kyu

    2013-11-01

    In this paper, the effects of annealing conditions on the dielectric properties of solution-processed aluminum oxide (Al2O3) layers for indium-zinc-tin-oxide (IZTO) thin-film transistors (TFTs) have been investigated. The dielectric properties of Al2O3 layers such as leakage current density and dielectric strength were largely affected by their annealing conditions. In particular, oxygen partial pressure in rapid thermal annealing, and the temperature profile of hot plate annealing had profound effects on the dielectric properties. From a refractive index analysis, the enhanced dielectric properties of Al2O3 gate dielectrics can be attributed to higher film density depending on the annealing conditions. With the low-temperature-annealed Al2O3 gate dielectric at 350 degrees C, solution-processed IZTO TFTs with a field-effect mobility of approximately 2.2 cm2/Vs were successfully fabricated. PMID:24245333

  13. Novel zinc(II)phthalocyanines bearing azo-containing schiff base: Determination of pKa values, absorption, emission, enzyme inhibition and photochemical properties

    NASA Astrophysics Data System (ADS)

    Kantar, Cihan; Mavi, Vildan; Baltaş, Nimet; İslamoğlu, Fatih; Şaşmaz, Selami

    2016-10-01

    Azo-containing schiff bases are well known and there are many studies about their various properties in literature. However, phthalocyanines bearing azo-containing schiff bases, their spectral, analytical and biological properties are unknown. Therefore, new zinc (II) phthalocyanines bearing azo-containing schiff base were synthesized and investigated to determine pKa values, absorption, emission, enzyme inhibition and photochemical properties. Emission spectra were reported and large Stokes shift values were determined for all compounds, indicating that all molecules exhibit excited state intramolecular proton transfer. These phthalocyanines were the first examples of phthalocyanine showing excited state intramolecular proton transfer. Singlet oxygen quantum yields of zinc (II) phthalocyanines were determined. pKa values and indicator properties of all compounds were investigated by potentiometry. All compounds were assayed for inhibitory activity against bovine milk xanthine oxidase and acetylcholinesterase enzyme in vitro. Compound 2 showed the high inhibitory effect against xanthine oxidase (IC50 = 0.24 ± 0.01 μM). However, phthalocyanine compounds did not show enzyme inhibitor behavior.

  14. 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

  15. Zinc and its importance for human health: An integrative review.

    PubMed

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

    2013-02-01

    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.

  16. Influence of amino acid replacement at position 198 on catalytic properties of zinc-bound water in human carbonic anhydrase III.

    PubMed

    LoGrasso, P V; Tu, C; Chen, X; Taoka, S; Laipis, P J; Silverman, D N

    1993-06-01

    Carbonic anhydrase III, found predominantly in skeletal muscle, is the least efficient of the mammalian carbonic anhydrases in catalyzing the hydration of CO2. Phenylalanine-198 is located on the hydrophobic side of the active-site cavity with its phenyl ring in the proximity of the catalytically active zinc-bound water. We replaced phenylalanine-198 in human carbonic anhydrase III with seven other amino acids (Ala, Asn, Asp, His, Leu, Tyr, Val) using site-directed mutagenesis. The catalytic properties of these enzymes were determined by stopped-flow spectrophotometry, and the exchange of 18O between CO2 and water was measured by mass spectrometry. All of the mutants had maximal values of kcat/Km for the hydration of CO2 enhanced, and five of the mutants had the pKa of the zinc-bound water increased compared with the wild-type enzyme. The largest effects were observed with the replacement Phe-198-->Asp which increased the maximal kcat/Km 140-fold and increased the pKa of the zinc-bound water from near 5 to 9.2. A Brønsted correlation was observed between log(kcat/Km) for hydration of CO2 and the pKa of the zinc-bound water (correlation coefficient r = 0.92); in addition, this pKa was inversely correlated with hydrophobicity of the residue at 198 (correlation coefficient r = -0.83). A direct correlation between the logarithm of the maximal kcat/Km for hydration and the logarithm of the pH-independent value of Ki for inhibition by cyanate (r = 0.95) indicated that the effect of the mutations at residue 198 occurred in large part by enhancement of the rate of dissociation of the enzyme-bicarbonate complex. PMID:8504098

  17. Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 11, October 1-December 31, 1981

    SciTech Connect

    Bube, R.H.

    1981-01-01

    Variations in crystal growth techniques are continuing with the goal of: (1) improving single crystal quality; and (2) producing variations in crystal properties by doping and post-growth variations of stoichiometry. DLTS measurements using Mg/Zn/sub 3/P/sub 2/ Schottky diodes gave information on three deep levels between 0.55 and 0.66 eV above the valence band in sublimation grown crystals with densities in the 10/sup 15/ to 10/sup 16/ cm/sup -3/ range, and a shallower level at 0.12 eV with a density of 10/sup 15/ cm/sup -3/ in an iodine-transport grown crystal. Investigation of surface properties of Zn/sub 3/P/sub 2/ indicate that a Br-MeOH etch leaves a Zn-rich surface for both sublimation-grown and iodine-transport grown crystals. Detailed measurements were made on thick Mg/Zn/sub 3/P/sub 2/ junctions on sublimation-grown and iodine-transport grown crystals of log J-V characteristics as a function of temperature, for crystal substrates as etched, and after heat treatment in hydrogen at several temperatures. A systematic change in the junction transport mechanism from tunneling at heat-treatment temperatures less than 300/sup 0/C to recombination/generation for heat-treatment temperatures between 300 and 500/sup 0/C was found for Zn/sub 3/P/sub 2/ crystals grown by both growth techniques. A simple model involving a depletion of free carrier density near the surface as a result of heat treatment in hydrogen is proposed. Thin film Mg/Zn/sub 3/P/sub 2/ cells showed log J-V characteristics that are strongly light dependent, indicating an increase in tunneling with illumination. Evidence that the barrier height of the Mg/Zn/sub 3/P/sub 2/ junction is actually of the order of 0.9 to 1.0 eV was obtained. Attempts to prepare ITO/Zn/sub 3/P/sub 2/ junctions by electron-beam evaporation of ITO on single crystal substrates yielded poor diodes and negligible photovoltaic behavior.

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

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming; Xu, Bing; Wang, Bao-Cheng; Xie, Juan; Yuan, Fei; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

    2014-08-01

    Five zinc(II) metal-organic frameworks, [Zn3(344-pytpy)2Cl6]n·n(H2O) (1), [Zn(344-pytpy)(ox)]n (2), [Zn2(344-pytpy)(bdc)2]n·1.5n(H2O) (3), [Zn2(344-pytpy)2 (sfdb)2]n·1.5n(H2O) (4) and [Zn3(344-pytpy)2(btc)2]n·2n(H2O) (5), (344-pytpy=4‧-(3-pyridyl)-4,2‧:6‧,4″-terpyridine, H2ox=oxalic acid, H2bdc=1,4-benzenedi-carboxylic acid, H2sfdb=4,4‧-sulfonyldibenzoic acid and H3btc=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 ZnII 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 66. Compound 3 displays a unusual 3-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,3,4)-connected topological net with the Schläfli symbol of (4.82)(4.85)(83). Compound 4 features a two-fold interpenetrating 4-connected 2D framework with the sql topological net and the Schläfli symbol of (44.62). Compound 5 is a new self-interpenetrating (3,3,4,4)-connected topological net with the Schläfli symbol of (6.82)2(62.82.10.12)(62.83.10)2(62.8)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.

  19. Saccharide substituted zinc phthalocyanines: optical properties, interaction with bovine serum albumin and near infrared fluorescence imaging for sentinel lymph nodes.

    PubMed

    Lu, Li; Lv, Feng; Cao, Bo; He, Xujun; Liu, Tianjun

    2014-01-03

    Saccharide-substituted zinc phthalocyanines, [2,9(10),16(17),23(24)-tetrakis((1-(β-D-glucose-2-yl)-1H-1,2,3-triazol-4-yl)methoxy)phthalocyaninato]zinc(II) and [2,9(10), 16(17),23(24)-tetrakis((1-(β-D-lactose-2-yl)-1H-1,2,3-triazol-4-yl)methoxy)phthalocyaninato] zinc(II), were evaluated as novel near infrared fluorescence agents. Their interaction with bovine serum albumin was investigated by fluorescence and circular dichroism spectroscopy and isothermal titration calorimetry. Near infrared imaging for sentinel lymph nodes in vivo was performed using nude mice as models. Results show that saccharide- substituted zinc phthalocyanines have favourable water solubility, good optical stability and high emission ability in the near infrared region. The interaction of lactose-substituted phthalocyanine with bovine serum albumin displays obvious differences to that of glucose- substituted phthalocyanine. Moreover, lactose-substituted phthalocyanine possesses obvious imaging effects for sentinel lymph nodes in vivo.

  20. Effect of Bi2O3 on structural, optical, and other physical properties of semiconducting zinc vanadate glasses

    NASA Astrophysics Data System (ADS)

    Punia, R.; Kundu, R. S.; Hooda, J.; Dhankhar, S.; Dahiya, Sajjan; Kishore, N.

    2011-08-01

    Zinc bismuth vanadate glasses with compositions 50V2O5-xBi2O3-(50-x) ZnO have been prepared using a conventional melt-quenching method and the solubility limit of Bi2O3 in zinc vanadate glass system has been investigated using x-ray diffraction. Density has been measured using Archimedes' principle; molar volume (Vm) and crystalline volumes (Vc) have also been estimated. With an increase in Bi2O3 content, there is an increase in density and molar volume of the glass samples. The glass transition temperature (Tg) and Hurby coefficient (Kgl) have been determined using differential scanning calorimetry (DSC) and are observed to increase with increase in Bi2O3 content (i.e., x), up to x = 15, thereby indicating the structural modifications and increased thermal stability of zinc vanadate glasses on addition of Bi2O3. FTIR spectra have been recorded and the analysis of FTIR shows that the structure depends upon the Bi2O3 content in the glass compositions. On addition of Bi2O3 into the zinc vanadate system, the structure of V2O5 changes from VO4 tetrahedral to VO5 trigonal bi-pyramid configuration. The optical parameters have been calculated by using spectroscopic ellipsometry for bulk oxide glasses (perhaps used first time for bulk glasses) and optical bandgap energy is found to increase with increase in Bi2O3 content.

  1. 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

  2. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide.

    PubMed

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

    2014-02-01

    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 (67)Zn and (70)Zn 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.

  3. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide.

    PubMed

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

    2014-02-01

    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 (67)Zn and (70)Zn 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

  4. Metallothionein I and II protect against zinc deficiency and zinc toxicity in mice.

    PubMed

    Kelly, E J; Quaife, C J; Froelick, G J; Palmiter, R D

    1996-07-01

    Metallothionein (MT)-bound zinc accumulates when animals are exposed to excess zinc and is depleted under conditions of zinc deficiency, suggesting that MT serves as a means of sequestering excess zinc as well as a zinc reservoir that can be utilized when zinc is deficient. To examine the importance of MT for these processes, mice with null alleles of both MT I and MT II genes were created and the zinc concentration and histological appearance of multiple organs assessed. At birth, the hepatic zinc concentration of these MT-null mice was lower than that of wild-type controls (0.27 +/- 0.02 vs. 0.65 +/- 0.11 micromol zinc/g tissue, P < 0.05). During the next 3 wk of suckling zinc-replete (95 micrograms zinc/g diet) dams, the hepatic zinc concentration of controls fell to 0.42 +/- 0.04 micromol/g but was unchanged in the MT-null mice (0.28 +/- 0.04 micromol/g). The most prominent histological anomaly observed at 3 wk of age was the presence of swollen Bowman's capsules in the kidneys of MT-null mice. When nursing MT-null dams were fed a severely zinc-deficient (1.5 microg/g) diet, kidney development in the MT-null pups was retarded as indicated by the retention of the nephrogenic zone and incomplete tubule development. We suggest that the lack of a hepatic reservoir of zinc jeopardizes the developing kidney in the MT-null mice. In addition to being more sensitive to dietary zinc restriction, MT-null mice are more sensitive to zinc toxicity. When adult mice were challenged with a ramping dose of zinc up to a total of 3700 micromol zinc/kg body weight, MT-null mice had a greater incidence of pancreatic acinar cell degeneration compared with control mice despite accumulating less zinc (2.72 +/- 0.46 vs. 1.23 +/- 0.52 micromol zinc/g pancreas, control and MT-null, respectively, P < 0.05). The results of these experiments suggest that MT I and MT II can protect against both zinc deficiency and zinc toxicity.

  5. Investigation of third order nonlinear optical properties of undoped and indium doped zinc oxide (InZnO) thin films by nanosecond Z-scan technique

    NASA Astrophysics Data System (ADS)

    Htwe, Zin Maung; Zhang, Yun-Dong; Yao, Cheng-Bao; Li, Hui; Li, Han-Yang; Yuan, Ping

    2016-02-01

    We report the investigation of third order nonlinear optical properties of undoped zinc oxide and indium doped zinc oxide thin films using nanosecond (6 ns, 18 μJ at 532 nm) Z-scan technique. Undoped (ZnO) and indium doped zinc oxide (InZnO) thin films were synthesized on quart silica substrate by using radio frequency (RF) magnetron sputtering technique. The structural and characterization of deposited thin films were analyzed by X-ray diffraction (XRD). In XRD results show different behaviors as amorphous oxide semiconductor and polycrystalline oxide semiconductor for ZnO and InZnO thin films respectively. Elemental compositions of thin films were analyzed by energy dispersive spectrometer (EDS). Surface morphology of ZnO and InZnO films were measured by using scanning electron microscopy (SEM), which show uniform and regular surface with small grain size distribution. Linear optical transmission and reflection thin films were analyzed by UV-VIS spectrometer. The UV-VIS results reveal that the optical transmittances of deposited thin films were increased after doping indium. The third order nonlinear optical properties of ZnO and InZnO thin films were carried out using nanosecond (6 ns) laser Z-scan technique at 532 nm wavelength. In open aperture case, both ZnO and InZnO thin films are show reverse saturable absorption (RSA) behaviors. For close-aperture Z-scan, the transmittance curve of ZnO thin film occurs as valley-peak (positive nonlinear refraction) characteristic, which indicates self-focusing behavior.

  6. Complex alloys containing double-Mackay clusters and (Sb(1-δ)Zn(δ))(24) snub cubes filled with highly disordered zinc aggregates: synthesis, structures, and physical properties of ruthenium zinc antimonides.

    PubMed

    Xiong, Ding-Bang; Zhao, Yufeng; Schnelle, Walter; Okamoto, Norihiko L; Inui, Haruyuki

    2010-12-01

    A series of cluster-based ruthenium zinc antimonides with a large unit cell were obtained. Their structures were solved by the single crystal X-ray diffraction methods. They crystallize in the cubic space group of Fm3̅c (No. 226) with cell dimensions of 25.098(3), 24.355(3), 24.307(3), and 24.376(3) Å for Ru(26)Sb(24)Zn(67) (CA), Ru(13)Sb(12)Zn(83.4) (CB), Ru(13)Sb(6.29)Zn(91.56) (CC), and Ru(13)Sb(17.1)Zn(74.8) (CD), respectively. By all indications, compounds CA and CB are two phases showing pronounced distinctions regarding compositions, lattice parameters, thermal and transport properties, but they are not members of an extended solid solution. Compounds CB, CC, and CD are three members of a same solid solution. Topologically, these four compounds contain face-centered cubic packing of double-Mackay type clusters and (Sb(1-δ)Zn(δ))(24) snub cubes filled with highly disordered zinc aggregates, with or without glue atoms between them. Both phases CA and CB are diamagnetic. There is a difference of ∼170 K between their thermally stable temperatures. CA exhibits rather low thermal conductivity with the value of ∼0.9 W m(-1) K(-1) at room temperature, which is about one-third that of CB. The electrical resistivity of CB is almost temperature independent. The Seebeck coefficient of CB is small and negative, while that of CA exhibits a complicated temperature dependence and undergoes a transition from p- to n-type conduction around room temperature.

  7. Creep Resistant Zinc Alloy

    SciTech Connect

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  8. Water Depletion Threatens Agriculture

    NASA Astrophysics Data System (ADS)

    Brauman, K. A.; Richter, B. D.; Postel, S.; Floerke, M.; Malsy, M.

    2014-12-01

    Irrigated agriculture is the human activity that has by far the largest impact on water, constituting 85% of global water consumption and 67% of global water withdrawals. Much of this water use occurs in places where water depletion, the ratio of water consumption to water availability, exceeds 75% for at least one month of the year. Although only 17% of global watershed area experiences depletion at this level or more, nearly 30% of total cropland and 60% of irrigated cropland are found in these depleted watersheds. Staple crops are particularly at risk, with 75% of global irrigated wheat production and 65% of irrigated maize production found in watersheds that are at least seasonally depleted. Of importance to textile production, 75% of cotton production occurs in the same watersheds. For crop production in depleted watersheds, we find that one half to two-thirds of production occurs in watersheds that have not just seasonal but annual water shortages, suggesting that re-distributing water supply over the course of the year cannot be an effective solution to shortage. We explore the degree to which irrigated production in depleted watersheds reflects limitations in supply, a byproduct of the need for irrigation in perennially or seasonally dry landscapes, and identify heavy irrigation consumption that leads to watershed depletion in more humid climates. For watersheds that are not depleted, we evaluate the potential impact of an increase in irrigated production. Finally, we evaluate the benefits of irrigated agriculture in depleted and non-depleted watersheds, quantifying the fraction of irrigated production going to food production, animal feed, and biofuels.

  9. Studies on the synthesis, spectral, optical and thermal properties of l-Valine Zinc Sulphate: an organic inorganic hybrid nonlinear optical crystal.

    PubMed

    Puhal Raj, A; Ramachandra Raja, C

    2012-11-01

    Nonlinear optical (NLO) organic inorganic hybrid l-Valine Zinc Sulphate (LVZS) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at 36°C using a constant temperature bath (CTB) with an accuracy of ±0.01°C. This crystal is reported with its characterization by single crystal and powder XRD, FTIR, UV-Vis-NIR, TG/DTA analysis and SHG test. Single crystal XRD study reveals that LVZS crystallizes in monoclinic system with the lattice constants a=9.969(3) Å, b=7.238(3) Å, c=24.334(9) Å and cell volume is 1736.00Å(3). Sharp peaks observed in powder X-ray diffraction studies confirm the high degree of crystallinity of grown crystal. The incorporation of sulphate ion with l-valine is confirmed by FTIR spectrum in LVZS crystal(.) A remarkable increase in optical transparency has been observed in LVZS when compared to l-valine and zinc sulphate heptahydrate Thermal properties of LVZS have been reported by using TG/DTA analysis. Kurtz powder second harmonic generation (SHG) test confirms NLO property of the crystal and SHG efficiency of LVZS was found to be 1.34 times more than pure l-valine.

  10. Half-metallic properties in rocksalt and zinc-blende M N ( M=Na, K): A first-principles study

    NASA Astrophysics Data System (ADS)

    Yan, E.

    2012-03-01

    Pseudopotentials and plane-wave basis set method is used to investigate the electronic structure and magnetic properties for state-of-the-art zinc-blende and rocksalt M N ( M=K, Na) alloys. We find that these compounds exhibit half-metallic characters with an integer magnetic moment of 2.00μB. The half-metallic properties result from a fully spin-polarization of s and p states. The origin of energy gap mainly comes from the hybridization both s and p states. Total energies calculations indicate the rocksalt phase is lower in energy than the zinc-blende one. The difference of total energy are about 0.035 Ry per formula unit for KN and NaN, respectively. For these compounds, Slater-Pauling curve Mt=(Zt-4) (in μB unit) is obeyed between valence electrons and total magnetic moment. Meanwhile, we also find the preservation of half metallic characters when the lattice parameter is moderate compressed.

  11. hZAC encodes a zinc finger protein with antiproliferative properties and maps to a chromosomal region frequently lost in cancer

    PubMed Central

    Varrault, A.; Ciani, E.; Apiou, F.; Bilanges, B.; Hoffmann, A.; Pantaloni, C.; Bockaert, J.; Spengler, D.; Journot, L.

    1998-01-01

    We previously reported the identification of mZac, a novel mouse zinc finger protein that shared with p53 the ability to regulate concomitantly apoptosis and cell cycle progression. We describe here the isolation, chromosomal localization, and functional in vitro characterization of its human homolog. hZAC is a widely expressed zinc finger protein that reveals transactivation and DNA-binding activity. hZAC inhibits tumor cell growth through induction of apoptotic cell death and G1 arrest. Thus hZAC, like its mouse counterpart, displays antiproliferative properties through pathways known to be central to the activity of p53. We mapped hZAC on chromosome 6q24-q25, a region frequently deleted in many solid tumors. Indeed, allelic loss at 6q24-q25 has been shown in breast and ovary cancers, melanomas, astrocytomas, and renal cell carcinomas. Furthermore, Abdollahi et al. [Abdollahi, A., Godwin, A. K., Miller, P. D., Getts, L. A., Schultz, D. C., Tagushi, T., Testa, J. R. & Hamilton, T. C. (1997) Cancer Res. 57, 2029–2034] recently isolated ZAC through its loss of expression in a surface epithelial ovary tumor model and accordingly named it Lot for “lost on transformation.” In view of these observations, the functional properties we report here provide further arguments to consider hZAC as a tumor suppressor gene candidate. PMID:9671765

  12. Influence of the Cation Ratio on Optical and Electrical Properties of Amorphous Zinc-Tin-Oxide Thin Films Grown by Pulsed Laser Deposition.

    PubMed

    Bitter, Sofie; Schlupp, Peter; Bonholzer, Michael; von Wenckstern, Holger; Grundmann, Marius

    2016-04-11

    Continuous composition spread (CCS) methods allow fast and economic exploration of composition dependent properties of multielement compounds. Here, a CCS method was applied for room temperature pulsed laser deposition (PLD) of amorphous zinc-tin-oxide to gain detailed insight into the influence of the zinc-to-tin cation ratio on optical and electrical properties of this ternary compound. Our CCS approach for a large-area offset PLD process utilizes a segmented target and thus makes target exchange or movable masks in the PLD chamber obsolete. Cation concentrations of 0.08-0.82 Zn/(Zn + Sn) were achieved across single 50 × 50 mm(2) glass substrates. The electrical conductivity increases for increasing tin content, and the absorption edge shifts to lower energies. The free carrier concentration can be tuned from 10(20) to 10(16) cm(-3) by variation of the cation ratio from 0.1 to 0.5 Zn/(Zn + Sn). PMID:27004935

  13. Novel adaptations to zinc-silicate glass polyalkenoate cements: the unexpected influences of germanium based glasses on handling characteristics and mechanical properties.

    PubMed

    Dickey, B T; Kehoe, S; Boyd, D

    2013-07-01

    Aluminum-free glass polyalkenoate cements (GPC) have been hindered for use as injectable bone cements by their inability to balance handling characteristics with mechanical integrity. Currently, zinc-based, aluminum-free GPCs demonstrate compression strengths in excess of 60MPa, but set in c. 1-2 min. Previous efforts to extend the setting reaction have remained clinically insufficient and are typically accompanied by a significant drop in strength. This work synthesized novel glasses based on a zinc silicate composition with the inclusion of GeO2, ZrO2, and Na2O, and evaluated the setting reaction and mechanical properties of the resultant GPCs. Germanium based GPCs were found to have working times between 5 and 10 min, setting times between 14 and 36 min, and compression strengths in excess of 30 MPa for the first 30 days. The results of this investigation have shown that the inclusion of GeO2, ZrO2, and Na2O into the glass network have produced, for the first time, an aluminum-free GPC that is clinically viable as injectable bone cements with regards to handling characteristics and mechanical properties.

  14. Studies on the synthesis, spectral, optical and thermal properties of L-Valine Zinc Sulphate: An organic inorganic hybrid nonlinear optical crystal

    NASA Astrophysics Data System (ADS)

    Puhal Raj, A.; Ramachandra Raja, C.

    2012-11-01

    Nonlinear optical (NLO) organic inorganic hybrid L-Valine Zinc Sulphate (LVZS) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at 36 °C using a constant temperature bath (CTB) with an accuracy of ±0.01 °C. This crystal is reported with its characterization by single crystal and powder XRD, FTIR, UV-Vis-NIR, TG/DTA analysis and SHG test. Single crystal XRD study reveals that LVZS crystallizes in monoclinic system with the lattice constants a = 9.969(3) Å, b = 7.238(3) Å, c = 24.334(9) Å and cell volume is 1736.00 Å3. Sharp peaks observed in powder X-ray diffraction studies confirm the high degree of crystallinity of grown crystal. The incorporation of sulphate ion with L-valine is confirmed by FTIR spectrum in LVZS crystal. A remarkable increase in optical transparency has been observed in LVZS when compared to L-valine and zinc sulphate heptahydrate Thermal properties of LVZS have been reported by using TG/DTA analysis. Kurtz powder second harmonic generation (SHG) test confirms NLO property of the crystal and SHG efficiency of LVZS was found to be 1.34 times more than pure L-valine.

  15. Synthesis, characterization and investigation of the photophysical and photochemical properties of highly soluble novel metal-free, zinc(II), and indium(III) phthalocyanines substituted with 2,3,6-trimethylphenoxy moieties.

    PubMed

    Gürel, Ekrem; Pişkin, Mehmet; Altun, Selçuk; Odabaş, Zafer; Durmuş, Mahmut

    2015-04-01

    This work presents the synthesis and characterization of metal-free, zinc(II), and indium(III)acetate phthalocyanines substituted with 2,3,6-trimethylphenoxy groups at the peripheral and non-peripheral positions. The photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines and unsubstituted zinc(II) and indium(III)acetate phthalocyanines were investigated in dimethylformamide solution. The effects of the types of substituents and their positions and the variety of central metal ions on the phthalocyanine core on their spectroscopic, photophysical and photochemical properties were also determined. The studied 2,3,6-trimethylphenoxy substituted metal-free, zinc(II) and indium(III)acetate phthalocyanines especially indium(III)acetate derivatives exhibited appropriate photophysical and photochemical properties such as high singlet oxygen generation and these phthalocyanines can be potential Type II photosensitizers for photodynamic therapy in cancer applications.

  16. Modification of optical and electrical properties of zinc oxide-coated porous silicon nanostructures induced by swift heavy ion.

    PubMed

    Kumar, Yogesh; Herrera-Zaldivar, Manuel; Olive-Méndez, Sion Federico; Singh, Fouran; Mathew, Xavier; Agarwal, Vivechana

    2012-07-02

    Morphological and optical characteristics of radio frequency-sputtered zinc aluminum oxide over porous silicon (PS) substrates were studied before and after irradiating composite films with 130 MeV of nickel ions at different fluences varying from 1 × 1012 to 3 × 1013 ions/cm2. The effect of irradiation on the composite structure was investigated by scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and cathodoluminescence spectroscopy. Current-voltage characteristics of ZnO-PS heterojunctions were also measured. As compared to the granular crystallites of zinc oxide layer, Al-doped zinc oxide (ZnO) layer showed a flaky structure. The PL spectrum of the pristine composite structure consists of the emission from the ZnO layer as well as the near-infrared emission from the PS substrate. Due to an increase in the number of deep-level defects, possibly oxygen vacancies after swift ion irradiation, PS-Al-doped ZnO nanocomposites formed with high-porosity PS are shown to demonstrate a broadening in the PL emission band, leading to the white light emission. The broadening effect is found to increase with an increase in the ion fluence and porosity. XRD study revealed the relative resistance of the film against the irradiation, i.e., the irradiation of the structure failed to completely amorphize the structure, suggesting its possible application in optoelectronics and sensing applications under harsh radiation conditions.

  17. Modification of optical and electrical properties of zinc oxide-coated porous silicon nanostructures induced by swift heavy ion

    PubMed Central

    2012-01-01

    Morphological and optical characteristics of radio frequency-sputtered zinc aluminum oxide over porous silicon (PS) substrates were studied before and after irradiating composite films with 130 MeV of nickel ions at different fluences varying from 1 × 1012 to 3 × 1013 ions/cm2. The effect of irradiation on the composite structure was investigated by scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and cathodoluminescence spectroscopy. Current–voltage characteristics of ZnO-PS heterojunctions were also measured. As compared to the granular crystallites of zinc oxide layer, Al-doped zinc oxide (ZnO) layer showed a flaky structure. The PL spectrum of the pristine composite structure consists of the emission from the ZnO layer as well as the near-infrared emission from the PS substrate. Due to an increase in the number of deep-level defects, possibly oxygen vacancies after swift ion irradiation, PS-Al-doped ZnO nanocomposites formed with high-porosity PS are shown to demonstrate a broadening in the PL emission band, leading to the white light emission. The broadening effect is found to increase with an increase in the ion fluence and porosity. XRD study revealed the relative resistance of the film against the irradiation, i.e., the irradiation of the structure failed to completely amorphize the structure, suggesting its possible application in optoelectronics and sensing applications under harsh radiation conditions. PMID:22748164

  18. Synthesis, crystal structure and spectroscopic properties of a supramolecular zinc(II) complex with N2O2 coordination sphere.

    PubMed

    Dong, Wen-Kui; Zhang, Li-Sha; Sun, Yin-Xia; Zhao, Meng-Meng; Li, Gang; Dong, Xiu-Yan

    2014-01-01

    A new hexa-coordinated zinc(II) complex, namely [ZnL(H2O)2]n, with N2O2 coordination sphere (H2L=4,4'-dibromo-6,6'-dichloro-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol) has been synthesized and structurally characterized by elemental analyses, IR, UV-vis spectra and TG-DTA analyses, etc. Crystallographic data are monoclinic, space group P2(1)/c, a=24.634(2)Å, b=10.144(1)Å, c=7.9351(6)Å, β=91.371(2)°, V=1982.4(3)Å(3), Dc=2.099 g/cm(3), Z=4. The zinc(II) complex exhibits a slightly distorted octahedral geometry with halogen-substituted Salen-type bisoxime forming the basal N2O2 coordination sphere and two oxygen atoms from two coordinated water molecules in the axial position. The hydrogen-bonding and π-π stacking interactions have stabilized the zinc(II) complex molecules to form a self-assembling infinite dual metal-water chain-like structure with the nearest Zn⋯Zn distance of 4.954(4)Å.

  19. Synthesis, characterization and electrical properties of peripherally tetra-aldazine substituted novel metal free phthalocyanine and its zinc(II) and nickel(II) complexes.

    PubMed

    Bayrak, Rıza; Dumludağ, Fatih; Akçay, Hakkı Türker; Değirmencioğlu, İsmail

    2013-03-15

    The novel phthalonitrile containing azine segment and its corresponding tetra aldazine substituted metal free- and metallo-phthalocyanines (Zn(II) and Ni(II)) were synthesized and characterized by IR, (1)H NMR, Mass, UV-Vis spectroscopy and elemental analysis and addition to these techniques for substituted phthalonitrile (13)C NMR have been used. In addition, dc and ac electrical properties of the films of these novel phthalocyanines were investigated as a function of temperature (295-523 K) and frequency (40-10(5)Hz). Activation energy values of the films of the phthalocyanines were calculated from straight portions of the Arrhenius plot (lnσ(dc)-1/T curves) as 0.70 eV, 0.93 eV and 0.91 eV for the films of metal free, nickel- and zinc-phthalocyanines, respectively. From impedance spectroscopy measurements, it is observed that bulk resistance decreases with increasing temperature indicating semiconductor property.

  20. Halo Star Lithium Depletion

    SciTech Connect

    Pinsonneault, M. H.; Walker, T. P.; Steigman, G.; Narayanan, Vijay K.

    1999-12-10

    The depletion of lithium during the pre-main-sequence and main-sequence phases of stellar evolution plays a crucial role in the comparison of the predictions of big bang nucleosynthesis with the abundances observed in halo stars. Previous work has indicated a wide range of possible depletion factors, ranging from minimal in standard (nonrotating) stellar models to as much as an order of magnitude in models that include rotational mixing. Recent progress in the study of the angular momentum evolution of low-mass stars permits the construction of theoretical models capable of reproducing the angular momentum evolution of low-mass open cluster stars. The distribution of initial angular momenta can be inferred from stellar rotation data in young open clusters. In this paper we report on the application of these models to the study of lithium depletion in main-sequence halo stars. A range of initial angular momenta produces a range of lithium depletion factors on the main sequence. Using the distribution of initial conditions inferred from young open clusters leads to a well-defined halo lithium plateau with modest scatter and a small population of outliers. The mass-dependent angular momentum loss law inferred from open cluster studies produces a nearly flat plateau, unlike previous models that exhibited a downward curvature for hotter temperatures in the 7Li-Teff plane. The overall depletion factor for the plateau stars is sensitive primarily to the solar initial angular momentum used in the calibration for the mixing diffusion coefficients. Uncertainties remain in the treatment of the internal angular momentum transport in the models, and the potential impact of these uncertainties on our results is discussed. The 6Li/7Li depletion ratio is also examined. We find that the dispersion in the plateau and the 6Li/7Li depletion ratio scale with the absolute 7Li depletion in the plateau, and we use observational data to set bounds on the 7Li depletion in main-sequence halo

  1. Uptake epithelia behave in a cell-centric and not systems homeostatic manner in response to zinc depletion and supplementation† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c3mt00212h Click here for additional data file.

    PubMed Central

    Zheng, Dongling; Feeney, Graham P.; Handy, Richard D.; Kille, Peter

    2013-01-01

    Much remains to be understood about systemic regulation of zinc uptake in vertebrates, and adequate zinc status is far from always achieved in animals or human. In addition to absorbing zinc from the diet, fish are able to take up zinc directly from the water with the gills. This provides an elegant system to study zinc uptake, how it relates to zinc status, and the expression of genes for proteins involved in zinc acquisition. A 21-day experiment was conducted in which zebrafish were acclimated to deficient, control or excess zinc concentrations in the water and feed. Deficient provision of zinc reduced whole body zinc, potassium, sodium and calcium levels whilst zinc concentrations in the uptake epithelia (gills and gut) remained unchanged. Excess levels of zinc caused accumulation of zinc in the gills, intestine and carcass, but impaired whole body iron, sodium and calcium concentrations. Fish subjected to zinc deficiency had, surprisingly, a reduced zinc influx across the gill epithelium, even when tested at a high concentration of zinc in the water. Zinc influx in the excess group was indistinct from the control. Expression of genes for metallothionein-2 (Mt2) and zinc transporters-1, -2, and -8 (Znt1, Znt2, Znt8) in uptake epithelia showed in general a direct relationship with zinc supply, while mRNA for Zip4 was inversely related to zinc supply. Transcripts for the epithelial calcium channel (Ecac/Trpv6) showed time-dependent increased expression in the gills of the deficiency group, and a transient decrease of expression during zinc excess. Transcriptome profiling by microarrays showed that in both gills and intestine, the most markedly affected biological functions were those related to cell growth, proliferation and cancer, closely followed by processes of gene transcription and protein synthesis in general. Whilst changes in zinc supply had profound effects in the intestine on genes associated with uptake and metabolism of macronutrients, many of the

  2. Battery depletion monitor

    SciTech Connect

    Lee, Y.S.

    1982-01-26

    A cmos inverter is used to compare pacemaker battery voltage to a referenced voltage. When the reference voltage exceeds the measured battery voltage, the inverter changes state to indicate battery depletion.

  3. Fluorescent and photochemical properties of a single zinc finger conjugated to a fluorescent DNA-binding probe.

    PubMed

    Thompson, M; Woodbury, N W

    2000-04-18

    A single zinc finger derived from the DNA-binding domain of the glucocorticoid receptor (GR) has been tethered to the intercalating fluorophore thiazole orange, and the DNA recognition characteristics of the conjugate have been examined. DNA sequence specificity for the peptide-dye conjugate, determined by steady-state fluorescence measurements and photoactivated DNA cleavage experiments, reproduce the binding features of response element recognition found in the native GR. The thiazole orange is able to intercalate and fluoresce when the conjugate binds, at concentrations where little fluorescence is observed from either the conjugate alone or the conjugate mixed with DNA lacking the zinc finger target sequence. The conjugate preferentially targets a 5'-TGTTCT-3' sequence (the native glucocorticoid receptor element) with a dissociation constant of about 25 nM. Lower binding affinities (up to 10-fold) are observed for single site variants of this sequence, and much lower affinity (40-50-fold) is observed for binding to the estrogen response element (which differs from the glucocorticoid receptor element at two positions) as well as to nonspecific DNA. Footprinting reactions show a 4-6 base pair region that is protected by the zinc finger moiety. Photocleavage assays reveal a several base pair region flanking the recognition sequence where the tethered thiazole orange moiety is able to intercalate and subsequently cleave DNA upon visible light exposure. Thiazole orange is also shown to oxidize the 5'-G of remote GG sequences, depending on the details of the intervening DNA sequence. Small synthetic protein-dye conjugates such as this one are potentially useful for a variety of purposes including sequence-specific probes that work under physiological conditions (without melting and hybridization of DNA), sequence-specific photocleavage agents, and self-assembling components in electron and energy transfer systems that utilize DNA as a scaffold and/or photochemical

  4. Effects of cation compositions on the electronic properties and optical dispersion of indium zinc tin oxide thin films by electron spectroscopy

    SciTech Connect

    Denny, Yus Rama; Seo, Soonjoo; Lee, Kangil; Oh, Suhk Kun; Kang, Hee Jae; Heo, Sung; Chung, Jae Gwan; Lee, Jae Cheol; Tougaard, Sven

    2015-02-15

    Highlights: • REELS analysis can provide optical dispersion and electronic properties of oxide materials. • The band gap varied with In/Zn/Sn compositions and increased after annealing. • The optical properties were examined using REELS in conjunction with the Tougaard–Yubero model. • The dispersion parameters were determined by a single-oscillator Wemple–DiDomenico model. • The Zn and Sn contents play a crucial role in determining the single-oscillator constant and dispersion energy of IZTO thin films. - Abstract: The electronic properties and optical dispersion of indium zinc tin oxide (IZTO) films with different cation compositions were investigated by reflection electron energy loss spectroscopy (REELS). The REELS spectra of IZTO films revealed that the band gap varied with different Sn/Zn ratios and In content. The optical properties were examined with REELS data using Tougaard–Yubero model and the results were compared with the envelope of the transmission spectra obtained using a UV-spectrometer. The dispersion behavior of the refractive index from REELS results was studied in terms of the single-oscillator Wemple–DiDomenico model. The results showed that the different compositions of In/Zn/Sn caused a change in the dispersion parameters of IZTO thin films in contrast to the static values of refractive indices and dielectric constant which remained the same. Our work demonstrated that REELS is an efficient tool to study the optical properties of a material by obtaining the optical parameters.

  5. Evaluation of Controlled-Release Property and Phytotoxicity Effect of Insect Pheromone Zinc-Layered Hydroxide Nanohybrid Intercalated with Hexenoic Acid.

    PubMed

    Ahmad, Rozita; Hussein, Mohd Zobir; Kadir, Wan Rasidah Wan Abdul; Sarijo, Siti Halimah; Hin, Taufiq-Yap Yun

    2015-12-30

    A controlled release formulation for the insect pheromone hexenoic acid (HE) was successfully developed using zinc-layered hydroxide (ZLH) as host material through a simple coprecipitation technique, resulting in the formation of inorganic-organic nanolayered material with sustained release properties. The release of HE from its nanohybrid was found to occur in a controlled manner, governed by a pseudo-second order kinetics model. The maximum amount of HE released from the nanocomposite into solutions at pH 4, 6.5, and 8 was found to be 84, 73, and 83% for 1100 min, respectively. The hexenoate zinc-layered hydroxide nanomaterial (HEN) was found to be nontoxic for plants when green beans and wheat seeds were successfully germinated in all HEN concentrations tested in the experiment, with higher percentage of seed germination and higher radical seed growth as compared to its counter anion, HE. ZLH can be a promising carrier for insect pheromone toward a new generation of environmentally safe pesticide nanomaterial for crop protection. PMID:26501358

  6. Effect of annealing temperature on antimicrobial and structural properties of bio-synthesized zinc oxide nanoparticles using flower extract of Anchusa italica.

    PubMed

    Azizi, Susan; Mohamad, Rosfarizan; Bahadoran, Azadeh; Bayat, Saadi; Rahim, Raha Abdul; Ariff, Arbakariya; Saad, Wan Zuhainis

    2016-08-01

    The use of nontoxic biological compounds in the synthesis of nanomaterials is an economic and eco-friendly approach. The present work was undertaken to develop zinc oxide nanoparticles (ZnO-NPs) by a green method using simple precursor from the solution consisting of zinc acetate and the flower extract of Anchusa italica (A. italica). Effect of annealing temperature on structural and antimicrobial properties was investigated. The crystalline structure of ZnO-NPs was shown using X-ray diffraction (XRD) analysis. Transmission electron microscopy (TEM) results showed that ZnO-NPs are hexagonal in shapes with mean particle size of ~8 and ~14nm at 100°C and 200°C annealing temperatures respectively. The optical band gap was increased from 3.27eV to 3.30eV with the decreasing of the particle size. The antimicrobial activity of ZnO-NPs towards Gram positive (Bacillus megaterium and Stapphylococcus aureus) and Gram negative (Escherichia coli and Salmonella typhimurium) pathogens decreased with the increasing of the heat treating temperature. In vitro cytotoxicity studies on Vero cells, a dose dependent toxicity with non-toxic effect of concentration below 142μg/mL was shown. The results indicated that A. italica is an appropriate reaction media to prepare ZnO-NPs for cosmetic and bio-medical productions. PMID:27318600

  7. Evaluation of Controlled-Release Property and Phytotoxicity Effect of Insect Pheromone Zinc-Layered Hydroxide Nanohybrid Intercalated with Hexenoic Acid.

    PubMed

    Ahmad, Rozita; Hussein, Mohd Zobir; Kadir, Wan Rasidah Wan Abdul; Sarijo, Siti Halimah; Hin, Taufiq-Yap Yun

    2015-12-30

    A controlled release formulation for the insect pheromone hexenoic acid (HE) was successfully developed using zinc-layered hydroxide (ZLH) as host material through a simple coprecipitation technique, resulting in the formation of inorganic-organic nanolayered material with sustained release properties. The release of HE from its nanohybrid was found to occur in a controlled manner, governed by a pseudo-second order kinetics model. The maximum amount of HE released from the nanocomposite into solutions at pH 4, 6.5, and 8 was found to be 84, 73, and 83% for 1100 min, respectively. The hexenoate zinc-layered hydroxide nanomaterial (HEN) was found to be nontoxic for plants when green beans and wheat seeds were successfully germinated in all HEN concentrations tested in the experiment, with higher percentage of seed germination and higher radical seed growth as compared to its counter anion, HE. ZLH can be a promising carrier for insect pheromone toward a new generation of environmentally safe pesticide nanomaterial for crop protection.

  8. Ligand centered radical pathway in catechol oxidase activity with a trinuclear zinc-based model: Synthesis, structural characterization and luminescence properties

    NASA Astrophysics Data System (ADS)

    Pal, Sukanta; Chowdhury, Biswajit; Patra, Moumita; Maji, Milan; Biswas, Bhaskar

    2015-06-01

    A new trinuclear zinc(II) complex, [Zn3(L)(NCS)2](NO3)2·CH3OH·H2O (1), of a (N,O)-donor compartmental Schiff base ligand (H2L = N,N‧-bis(3-methoxysalicylidene)-1,3-diamino-2-propanol), has been synthesized in crystalline phase. The zinc(II) complex has been characterized by elemental analysis, IR spectroscopy, UV-Vis spectroscopy, powder X-ray diffraction study (PXRD), 1H NMR, EI mass spectrometry and thermogravimetric analysis. PXRD revealed that 1 crystallizes in P - 1 space group with a = 9.218 Å, b = 10.849 Å, c = 18.339 Å, with unit cell volume is 2179.713 (Å)3. Fluorescence spectra in methanolic solution reflect that intensity of emission for 1 is much higher compared to H2L and both the compounds exhibit good fluorescence properties. The complex 1 exhibits significant catalytic activities of biological relevance, viz. catechol oxidase. In methanol, it efficiently catalyzes the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to corresponding quinone via formation of a dinuclear species as [Zn2(L)(3,5-DTBC)]. Electron Paramagnetic Resonance (EPR) experiment suggests generation of radicals in the presence of 3,5-DTBC and it may be proposed that the radical pathway is probably responsible for conversion of 3,5-DTBC to 3,5-DTBQ promoted by complex of redox-innocent Zn(II) ion.

  9. Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet

    PubMed Central

    Claeyssen, Richard; Andriollo-Sanchez, Maud; Arnaud, Josiane; Touvard, Laurence; Alonso, Antonia; Chancerelle, Yves; Roussel, Anne-Marie; Agay, Diane

    2008-01-01

    As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn induced oxidative stress, in an animal model. After eight weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled one to ten days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters and antioxidant enzymes were also studied in blood and organs. The zinc depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients. PMID:18773151

  10. The zinc electrode - Its behaviour in the nickel oxide-zinc accumulator

    NASA Astrophysics Data System (ADS)

    Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling.

  11. Associations between dietary iron and zinc intakes, and between biochemical iron and zinc status in women.

    PubMed

    Lim, Karen; Booth, Alison; Szymlek-Gay, Ewa A; Gibson, Rosalind S; Bailey, Karl B; Irving, David; Nowson, Caryl; Riddell, Lynn

    2015-04-20

    Iron and zinc are found in similar foods and absorption of both may be affected by food compounds, thus biochemical iron and zinc status may be related. This cross-sectional study aimed to: (1) describe dietary intakes and biochemical status of iron and zinc; (2) investigate associations between dietary iron and zinc intakes; and (3) investigate associations between biochemical iron and zinc status in a sample of premenopausal women aged 18-50 years who were recruited in Melbourne and Sydney, Australia. Usual dietary intakes were assessed using a 154-item food frequency questionnaire (n = 379). Iron status was assessed using serum ferritin and hemoglobin, zinc status using serum zinc (standardized to 08:00 collection), and presence of infection/inflammation using C-reactive protein (n = 326). Associations were explored using multiple regression and logistic regression. Mean (SD) iron and zinc intakes were 10.5 (3.5) mg/day and 9.3 (3.8) mg/day, respectively. Median (interquartile range) serum ferritin was 22 (12-38) μg/L and mean serum zinc concentrations (SD) were 12.6 (1.7) μmol/L in fasting samples and 11.8 (2.0) μmol/L in nonfasting samples. For each 1 mg/day increase in dietary iron intake, zinc intake increased by 0.4 mg/day. Each 1 μmol/L increase in serum zinc corresponded to a 6% increase in serum ferritin, however women with low serum zinc concentration (AM fasting < 10.7 μmol/L; AM nonfasting < 10.1 μmol/L) were not at increased risk of depleted iron stores (serum ferritin <15 μg/L; p = 0.340). Positive associations were observed between dietary iron and zinc intakes, and between iron and zinc status, however interpreting serum ferritin concentrations was not a useful proxy for estimating the likelihood of low serum zinc concentrations and women with depleted iron stores were not at increased risk of impaired zinc status in this cohort.

  12. Zinc phosphide

    Integrated Risk Information System (IRIS)

    Zinc phoshide ; CASRN 1314 - 84 - 7 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 Noncarcinogenic Ef

  13. Zinc cyanide

    Integrated Risk Information System (IRIS)

    Zinc cyanide ; CASRN 557 - 21 - 1 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 Noncarcinogenic Effe

  14. Lattice dynamics properties of XAs (X=Al, Ga and In) with zinc-blende structure from first-principle calculations

    NASA Astrophysics Data System (ADS)

    Li, Xingxiu; Tao, Xiaoma; Li, Ran; Chen, Hongmei; Ouyang, Yifang; Du, Yong

    2012-08-01

    Band structures, density of states, dielectric and vibrational properties of XAs (X=Al, Ga and In) alloys with zinc-blende structure have been studied using the density functional theory (DFT). The calculated lattice constants, band gap, static dielectric constants and phonon frequencies are all in good agreement with the available experimental data and other theoretical results. The calculated results show that Born effective charges ZB increase with cation mass. A similar tendency has been observed for phonon frequencies ωTO and ωLO. Calculation results prove that static dielectric constants ɛ(0) increase with atomic weight, i.e. in the sequences AlAs-GaAs-InAs, and show an inverse sequence for band gap.

  15. Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Jabena Begum, N.; Mohan, R.; Ravichandran, K.

    2013-01-01

    Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

  16. In vitro comparison of antibacterial properties of bioceramic-based sealer, resin-based sealer and zinc oxide eugenol based sealer and two mineral trioxide aggregates

    PubMed Central

    Singh, Gurpreet; Gupta, Iti; Elshamy, Faheim M. M.; Boreak, Nezar; Homeida, Husham Elraih

    2016-01-01

    Objective: Our goal of the study was to evaluate the antibacterial properties of endodontic sealers against the E. faecalis. Materials and Methods: Six millimeters wells were made for each material in all the preinoculated petri plates. Then, the petri plates were incubated for 24 h. The zones of inhibition appeared were measured, and the measurements were put to statistical analysis. Results: EndoSequence BC Sealer, MM-mineral trioxide aggregate (MTA), and ProRoot MTA showed maximum means of diameter of zones of inhibition, whereas MM-seal and Endoseal did not show any zones of inhibition. Conclusion: EndoSequence BC Sealer was found to be a better endodontic sealer as compared to resin-based and zinc oxide-eugenol-based sealer. PMID:27403055

  17. Speciation and thermodynamic properties of zinc in sulfur-rich hydrothermal fluids: Insights from ab initio molecular dynamics simulations and X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Mei, Yuan; Etschmann, Barbara; Liu, Weihua; Sherman, David M.; Testemale, Denis; Brugger, Joël

    2016-04-01

    Chlorine and sulfur are the main elements involved in the complexing of metals in ore-forming fluids. The nature and thermodynamic properties of the Zn(II)-Cl complexes have been investigated by previous experimental and theoretical studies and are now well established up to high temperatures (600 °C). In contrast, the role of bisulfide complexes for zinc speciation in sulfur-bearing fluids remains poorly known, and a better understanding of Zn(II)-HS complexation is required for modeling zinc transport in magmatic and metamorphic fluids and for optimizing the hydrometallurgical processing of sulfide ores. We have conducted ab initio molecular dynamics (MD) simulations to calculate the speciation of Zn(II)-HS complexes from ambient to hydrothermal-magmatic conditions (25-600 °C, up to 2000 bar). These theoretical calculations were complemented by X-ray absorption spectroscopy (XAS) measurements of Zn(II) in HS--rich solutions at 200-500 °C and 600-1000 bar. The speciation and geometrical properties predicted by the ab initio MD simulations and the in situ XAS data are in excellent agreement. Upon heating from room temperature to 250 °C, Zn(II) speciation in HS--rich solutions shows a transition from the sixfold octahedral hexaaquo complex [Zn(H2O)6]2+ to fourfold tetrahedral [Zn(HS)n(H2O)4-n]2-n complexes (n = 1-4). Ab initio MD simulations also show that at temperatures > 250 °C, the threefold trigonal-planar [Zn(HS)3]- complex becomes increasingly stable, and predominates in S-rich solutions; in contrast, chloro-complexes display a tetrahedral geometry at 25-500 °C, while trigonal planar ZnCl3- predominates at temperatures > 500 °C. The stability constants of Zn(II)-HS complexes were calculated by thermodynamic integration of constrained ab initio MD simulations at 200, 350 and 600 °C. The stability constants generated from this study predict that zinc can be transported by HS- at high temperature in reduced, neutral to alkaline solutions, while Zn

  18. Effect of Chloride Depletion on the Magnetic Properties and the Redox Leveling of the Oxygen-Evolving Complex in Photosystem II.

    PubMed

    Amin, Muhamed; Pokhrel, Ravi; Brudvig, Gary W; Badawi, Ashraf; Obayya, S S A

    2016-05-12

    Chloride is an essential cofactor in the oxygen-evolution reaction that takes place in photosystem II (PSII). The oxygen-evolving complex (OEC) is oxidized in a linear four-step photocatalytic cycle in which chloride is required for the OEC to advance beyond the S2 state. Here, using density functional theory, we compare the energetics and spin configuration of two different states of the Mn4CaO5 cluster in the S2 state: state A with Mn1(3+) and B with Mn4(3+) with and without chloride. The calculations suggest that model B with an S = 5/2 ground state occurs in the chloride-depleted PSII, which may explain the presence of the EPR signal at g = 4.1. Moreover, we use multiconformer continuum electrostatics to study the effect of chloride depletion on the redox potential associated with the S1/S2 and S2/S3 transitions. PMID:27077688

  19. Effect of Thermal Shock During Legionella Bacteria Removal on the Corrosion Properties of Zinc-Coated Steel Pipes

    NASA Astrophysics Data System (ADS)

    Orlikowski, Juliusz; Ryl, Jacek; Jazdzewska, Agata; Krakowiak, Stefan

    2016-07-01

    The purpose of this investigation was to conduct the failure analysis of a water-supply system made from zinc-coated steel. The observed corrosion process had an intense and complex character. The brownish deposits and perforations were present after 2-3 years of exploitation. The electrochemical study based on the Tafel polarization, corrosion potential monitoring, and electrochemical impedance spectroscopy together with microscopic analysis via SEM and EDX were performed in order to identify the cause of such intense corrosion. The performed measurements allowed us to determine that thermal shock was the source of polarity-reversal phenomenon. This process had begun the corrosion of steel which later led to the formation of deposits and perforations in the pipes. The work includes appropriate action in order to efficiently identify the described corrosion threat.

  20. Enhanced field emission properties from well-aligned zinc oxide nanoneedles grown on the Au/Ti/n-Si substrate

    SciTech Connect

    Park, Chan Jun; Choi, Duck-Kyun; Yoo, Jinkyoung; Yi, Gyu-Chul; Lee, Cheol Jin

    2007-02-19

    The authors investigated the field emission from vertically well-aligned zinc oxide (ZnO) nanoneedles grown on the Au/Ti/n-Si (100) substrate using metal organic chemical vapor deposition. The turn-on field of ZnO nanoneedles was about 0.85 V/{mu}m at the current density of 0.1 {mu}A/cm{sup 2}, and the emission current density of 1 mA/cm{sup 2} was achieved at the applied electric field of 5.0 V/{mu}m. The low turn-on field of the ZnO nanoneedles was attributed to very sharp tip morphology, and the high emission current density was mainly caused by the formation of the stable Ohmic contact between the ZnO nanoneedles and Au film.

  1. The electrical properties of 60 keV zinc ions implanted into semi-insulating gallium arsenide

    NASA Technical Reports Server (NTRS)

    Littlejohn, M. A.; Anikara, R.

    1972-01-01

    The electrical behavior of zinc ions implanted into chromium-doped semiinsulating gallium arsenide was investigated by measurements of the sheet resistivity and Hall effect. Room temperature implantations were performed using fluence values from 10 to the 12th to 10 to the 15th power/sq cm at 60 keV. The samples were annealed for 30 minutes in a nitrogen atmosphere up to 800 C in steps of 200 C and the effect of this annealing on the Hall effect and sheet resistivity was studied at room temperature using the Van der Pauw technique. The temperature dependence of sheet resistivity and mobility was measured from liquid nitrogen temperature to room temperature. Finally, a measurement of the implanted profile was obtained using a layer removal technique combined with the Hall effect and sheet resistivity measurements.

  2. Effect of boron doping on optical properties of sol-gel based nanostructured zinc oxide films on glass

    SciTech Connect

    Jana, Sunirmal; Vuk, Angela Surca; Mallick, Aparajita; Orel, Boris; Biswas, Prasanta Kumar

    2011-12-15

    Graphical abstract: Room temperature fine structured UV-vis PL emissions (a) as phonon replicas in 1 at.% boron doped film originated from LO phonon evidenced from Near Grazing Incidence Angle (NGIA) IR spectral study (b). Highlights: Black-Right-Pointing-Pointer Sol-gel based boron doped nanostructured ZnO thin films deposited on pure silica glass using crystalline boric acid as boron source. Black-Right-Pointing-Pointer Observed first time, room temperature fine structured PL emissions in 1 at.% doped film as phonon replicas originated from LO phonon (both IR and Raman active). Black-Right-Pointing-Pointer Boron doping controls the LO phonon energy in addition to visible reflection, band gap and grain size. Black-Right-Pointing-Pointer The films possessed mixed crystal phases with hexagonal as major phase. -- Abstract: Boron doped zinc oxide thin films ({approx}80 nm) were deposited onto pure silica glass by sol-gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24-2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

  3. Zinc Plasma Emission from Zinc Oxide Ceramics under a Microwave Electric Field

    NASA Astrophysics Data System (ADS)

    Sonobe, Taro; Mitani, Tomohiko; Hachiya, Kan; Shinohara, Naoki; Ohgaki, Hideaki

    2010-08-01

    We studied the effects of microwave irradiation on ZnO ceramics under vacuum to clarify the emission of zinc and oxygen plasmas from ZnO, while simultaneously focusing on the material's optical properties. We observed the emission of zinc and oxygen plasmas during intense absorption of microwaves as well as the deposition of zinc and zinc oxide films. Absorption coefficient and photoluminescence spectra suggest that zinc and oxygen plasmas were produced from grain surfaces of ZnO by microwave irradiation under vacuum, a phenomenon which was observed in a previous study on TiO2 [Jpn. J. Appl. Phys. 48 (2009) 116003].

  4. Beneficial effect of zinc supplementation on biomechanical properties of femoral distal end and femoral diaphysis of male rats chronically exposed to cadmium.

    PubMed

    Brzóska, Malgorzata M; Galazyn-Sidorczuk, Malgorzata; Rogalska, Joanna; Roszczenko, Alicja; Jurczuk, Maria; Majewska, Katarzyna; Moniuszko-Jakoniuk, Janina

    2008-02-15

    The present study was aimed at estimate, based on the rat model of human moderate and relatively high chronic exposure to cadmium (Cd), whether zinc (Zn) supplementation may prevent Cd-induced weakening in the bone biomechanical properties. For this purpose, male Wistar rats were administered Cd (5 or 50 mg/l) or/and Zn (30 or 60 mg/l) in drinking water for 6 and 12 months. Bone mineral density (BMD) and biomechanical properties (yield load, ultimate load, post-yield load, displacement at yield and at ultimate, stiffness, work to fracture, yield stress, ultimate stress and Young modulus of elasticity) of the femoral distal end and femoral diaphysis were examined. Biomechanical properties of the distal femur were estimated in a compression test, whereas those of the femoral diaphysis -- in a three-point bending test. Exposure to Cd, in a dose and duration dependent manner, decreased the BMD and weakened the biomechanical properties of the femur at its distal end and diaphysis. Zn supplementation during Cd exposure partly, but importantly, prevented the weakening in the bone biomechanical properties. The favorable Zn influence seemed to result from an independent action of this bioelement and its interaction with Cd. However, Zn supply at the exposure to Cd had no statistically significant influence on the BMD at the distal end and diaphysis of the femur. The results of the present paper suggest that Zn supplementation during exposure to Cd may have a protective influence on the bone tissue biomechanical properties, and in this way it can, at least partly, decrease the risk of bone fractures. The findings seem to indicate that enhanced dietary Zn intake may be beneficial for the skeleton in subjects chronically exposed to Cd.

  5. Influence of Oxygen Gas Ratio on the Properties of Aluminum-Doped Zinc Oxide Films Prepared by Radio Frequency Magnetron Sputtering.

    PubMed

    Kim, Minha; Jang, Yong-Jun; Jung, Ho-Sung; Song, Woochang; Kang, Hyunil; Kim, Eung Kwon; Kim, Donguk; Yi, Junsin; Lee, Jaehyeong

    2016-05-01

    Aluminum-doped zinc oxide (AZO) thin films were deposited on glass and polyimide substrates using radio frequency magnetron sputtering. We investigated the effects of the oxygen gas ratio on the properties of the AZO films for Cu(In,Ga)Se2 thin-film solar cell applications. The structural and optical properties of the AZO thin films were measured using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-Visible-NIR spectrophotometry. The oxygen gas ratio played a crucial role in controlling the optical as well as electrical properties of the films. When oxygen gas was added into the film, the surface AZO thin films became smoother and the grains were enlarged while the preferred orientation changed from (0 0 2) to (1 0 0) plane direction of the hexagonal phase. An improvement in the transmittance of the AZO thin films was achieved with the addition of 2.5-% oxygen gas. The electrical resistivity was highly increased even for a small amount of the oxygen gas addition.

  6. The Role of Porphyrin-Free-Base in the Electronic Structures and Related Properties of N-Fused Carbazole-Zinc Porphyrin Dye Sensitizers

    PubMed Central

    Li, Xing-Yu; Zhang, Cai-Rong; Wu, You-Zhi; Zhang, Hai-Min; Wang, Wei; Yuan, Li-Hua; Yang, Hua; Liu, Zi-Jiang; Chen, Hong-Shan

    2015-01-01

    Dye sensitizers can significantly affect power conversion efficiency of dye-sensitized solar cells (DSSCs). Porphyrin-based dyes are promising sensitizers due to their performances in DSSCs. Here, based upon a N-fused carbazole-zinc porphyrin-free-base porphyrin triad containing an ethynyl-linkage (coded as DTBC), the novel porphyrin dyes named DTBC-MP and DTBC-TP were designed by varying the porphyrin-free-base units in the π conjugation of DTBC in order to study the effect of porphyrin-free-base in the modification of electronic structures and related properties. The calculated results indicate that, the extension of the conjugate bridge with the porphyrin-free-base unit results in elevation of the highest occupied molecular orbital (HOMO) energies, decrease of the lowest unoccupied molecular orbital (LUMO) energies, reduction of the HOMO-LUMO gap, red-shift of the absorption bands, and enhancement of the absorbance. The free energy changes demonstrate that introducing more porphyrin-free-base units in the conjugate bridge induces a faster rate of electron injection. The transition properties and molecular orbital characters suggest that the different transition properties might lead to a different electron injection mechanism. In terms of electronic structure, absorption spectra, light harvesting capability, and free energy changes, the designed DTBC-TP is a promising candidate dye sensitizer for DSSCs. PMID:26610469

  7. Influence of Oxygen Gas Ratio on the Properties of Aluminum-Doped Zinc Oxide Films Prepared by Radio Frequency Magnetron Sputtering.

    PubMed

    Kim, Minha; Jang, Yong-Jun; Jung, Ho-Sung; Song, Woochang; Kang, Hyunil; Kim, Eung Kwon; Kim, Donguk; Yi, Junsin; Lee, Jaehyeong

    2016-05-01

    Aluminum-doped zinc oxide (AZO) thin films were deposited on glass and polyimide substrates using radio frequency magnetron sputtering. We investigated the effects of the oxygen gas ratio on the properties of the AZO films for Cu(In,Ga)Se2 thin-film solar cell applications. The structural and optical properties of the AZO thin films were measured using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-Visible-NIR spectrophotometry. The oxygen gas ratio played a crucial role in controlling the optical as well as electrical properties of the films. When oxygen gas was added into the film, the surface AZO thin films became smoother and the grains were enlarged while the preferred orientation changed from (0 0 2) to (1 0 0) plane direction of the hexagonal phase. An improvement in the transmittance of the AZO thin films was achieved with the addition of 2.5-% oxygen gas. The electrical resistivity was highly increased even for a small amount of the oxygen gas addition. PMID:27483888

  8. Cholesterol depletion induces autophagy

    SciTech Connect

    Cheng, Jinglei; Ohsaki, Yuki; Tauchi-Sato, Kumi; Fujita, Akikazu; Fujimoto, Toyoshi . E-mail: tfujimot@med.nagoya-u.ac.jp

    2006-12-08

    Autophagy is a mechanism to digest cells' own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5 mM methyl-{beta}-cyclodextrin or 10-20 {mu}g/ml nystatin for 1 h, or metabolically by 20 {mu}M mevastatin and 200 {mu}M mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks' solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, >50 {mu}m in length. The increase of LC3-II by methyl-{beta}-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of rapamycin. By electron microscopy, autophagic vacuoles induced by cholesterol depletion were indistinguishable from those seen after amino acid starvation. These results demonstrate that a decrease in cholesterol activates autophagy by a phosphatidylinositol 3-kinase-dependent mechanism.

  9. Charge depletion meter

    NASA Astrophysics Data System (ADS)

    Schneider, J. F.

    1984-11-01

    This invention relates to a charge depletion meter apparatus having a current to frequency converter to sense and convert the current drain of a battery source to a digital signal which is divided and then accumulated in a counter. An LCD display unit displays the accumulated charge which is received from the counter.

  10. Magnetic pulsations from 0.1 to 4.0 Hz and associated plasma properties in the earth's subsolar magnetosheath and plasma depletion layer

    NASA Technical Reports Server (NTRS)

    Anderson, B. J.; Fuselier, S. A.

    1993-01-01

    AMPTE CCE magnetic field data acquired during periods of magnetospheric compressions when the spacecraft sampled the magnetosheath are analyzed on the basis of a dynamic spectral analysis covering frequencies 0.1 to 4.0 Hz. Ion and electron data are used to identify regions, to monitor the upstream shock geometry, and to evaluate moments of the proton distribution. Fourteen encounters representing 46 hr of observations are analyzed. A compilation of the temporal sequence of spectral structures shows that electromagnetic ion cyclotron (EMIC) waves occur next to the magnetopause, while mirror waves occur outside the region of EMIC waves. It is concluded that there is a close relationship between EMIC waves in the sheath and the plasma depletion layer. For quasi-parallel upstream conditions, the magnetic field power spectra often exhibit no band limited structures but only broadband noise.

  11. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: Structural and optical studies by DRS, FT-IR, XRD, FESEM investigations

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-01

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400 °C and 500 °C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm-1 can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm-1 are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide.

  12. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: structural and optical studies by DRS, FT-IR, XRD, FESEM investigations.

    PubMed

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm(-1) can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm(-1) are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide.

  13. Effect of zinc and lead on the physiological and biochemical properties of aquatic plant Lemna minor: its potential role in phytoremediation

    NASA Astrophysics Data System (ADS)

    Jayasri, M. A.; Suthindhiran, K.

    2016-01-01

    Plants have gained importance in situ bioremediation of heavy metals. In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor. L.minor were exposed to metals for 4 days and tested for its dry to fresh weight ratio (DW/FW), photosynthetic pigments production and protein content. The oxidative damage was detected by measuring catalase activity. L.minor showed tolerance against Zn2+ and Pb2+ at a concentration of 10 and 4 mg/l, respectively. Among the metals, Pb2+ showed a significant toxicity at 8 mg/l. High concentration (20 mg/l of Zn2+ and 8 mg/l of Pb2+) of the metals displayed a considerable negative effect on soluble proteins (13 fold decrease with Zn2+ and 4 fold decrease with Pb2+) and photosynthetic pigments (twofold decrease with Zn2+ and onefold decrease with Pb2+) and lead to a consequent reduction in number of fronds. Further, the catalase was greatly increased (twofold decrease with Zn2+ and sixfold decrease with Pb2+) under metal stress. The results indicate that L.minor withstands Zn2+ and Pb2+ toxicity up to the concentration of 10 and 4 mg/l, respectively. Hence, the metal tolerant property of this plant shall be exploited for bioremediation of Zinc and Lead in polluted water. Further, the detailed and wide range of heavy metal toxicity studies should be done to reveal the possible use of this plant on large scale bioremediation purpose.

  14. Enhanced electrical and optical properties of room temperature deposited Aluminium doped Zinc Oxide (AZO) thin films by excimer laser annealing

    NASA Astrophysics Data System (ADS)

    El hamali, S. O.; Cranton, W. M.; Kalfagiannis, N.; Hou, X.; Ranson, R.; Koutsogeorgis, D. C.

    2016-05-01

    High quality transparent conductive oxides (TCOs) often require a high thermal budget fabrication process. In this study, Excimer Laser Annealing (ELA) at a wavelength of 248 nm has been explored as a processing mechanism to facilitate low thermal budget fabrication of high quality aluminium doped zinc oxide (AZO) thin films. 180 nm thick AZO films were prepared by radio frequency magnetron sputtering at room temperature on fused silica substrates. The effects of the applied RF power and the sputtering pressure on the outcome of ELA at different laser energy densities and number of pulses have been investigated. AZO films deposited with no intentional heating at 180 W, and at 2 mTorr of 0.2% oxygen in argon were selected as the optimum as-deposited films in this work, with a resistivity of 1×10-3 Ω.cm, and an average visible transmission of 85%. ELA was found to result in noticeably reduced resistivity of 5×10-4 Ω.cm, and enhancing the average visible transmission to 90% when AZO is processed with 5 pulses at 125 mJ/cm2. Therefore, the combination of RF magnetron sputtering and ELA, both low thermal budget and scalable techniques, can provide a viable fabrication route of high quality AZO films for use as transparent electrodes.

  15. Influence of annealing temperature on the structural, optical and electrical properties of amorphous Zinc Sulfide thin films

    NASA Astrophysics Data System (ADS)

    Göde, F.; Güneri, E.; Kariper, A.; Ulutaş, C.; Kirmizigül, F.; Gümüş, C.

    2011-11-01

    Zinc sulfide films have been deposited on glass substrates at room temperature by the chemical bath deposition technique. The growth mechanism is studied using X-ray diffraction, scanning electron microscopy, optical absorption spectra and electrical measurements. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (100, 200, 300 400 and 500 °C) for 1 h. The annealed film was also characterized by structural, optical and electrical studies. The structural analyses revealed that the as-deposited film was amorphous, but after being annealed at 500 °C, it changed to polycrystalline. The optical band gap is direct with a value of 4.01 eV, but this value decreased to 3.74 eV with annealing temperature, except for the 500 °C anneal where it only decreased to 3.82 eV. The refractive index (n), extinction coefficient (k), and real (ɛ1) and imaginary (ɛ2) parts of the dielectric constant are evaluated. Raman peaks appearing at ~478 cm-1, ~546 cm-1, ~778 cm-1 and ~1082 cm-1 for the annealed film (500 °C) were attributed to [TOl+LAΣ, 2TOΓ, 2LO, 3LO phonons of ZnS. The electrical conductivities of both as-deposited and annealed films have been calculated to be of the order of ~10-10 (Ω cm)-1 .

  16. TEMPO-functionalized zinc phthalocyanine: synthesis, magnetic properties, and its utility for electrochemical sensing of ascorbic acid.

    PubMed

    Korkut, Sibel Eken; Akyüz, Duygu; Özdoğan, Kemal; Yerli, Yusuf; Koca, Atıf; Şener, M Kasım

    2016-02-21

    Zinc(ii) phthalocyanine (TEMPO-ZnPc), peripherally functionalized with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radicals is synthesized and its magneto structural and electrochemical behaviors are investigated. TEMPO-ZnPc shows multi-electron ring based reduction reactions and a TEMPO based oxidation reaction. Spectroelectrochemical measurements support these peak assignments. TEMPO-ZnPc is tested as a homogeneous and heterogeneous ascorbic acid (AA) sensor. Disappearance of TEMPO-ZnPc based reduction processes and the observation of new waves at around 0 and 1.20 V with respect to increasing AA concentration indicate the interaction of TEMPO-ZnPc with AA and usability of the complex as an electrochemical AA sensor. For practical usage as heterogeneous electrocatalysts for AA sensing, a glassy carbon electrode (GCE) is coated with TEMPO-ZnPc (GCE/TEMPO-ZnPc) and this modified electrode is tested as a heterogeneous AA sensor. The redox peak of GCE/TEMPO-ZnPc at 0.81 V decreases the peak current while a new wave is observed at 0.65 V during the titration of the electrolyte with AA. GCE/TEMPO-ZnPc sense AA with 1.75 × 10(-6) mol dm(-3) LOD with a sensitivity of 1.89 × 10(3) A cm mol(-1).

  17. Conducting and Optical Properties of Transparent Conducting Indium-Doped Zinc Oxide Thin Films by Sol-Gel Processing

    SciTech Connect

    Huang, S.; Kaydanova, T.; Miedaner, A.; Ginley, D.S.

    2004-01-01

    Transparent conducting oxides were successfully prepared from mixed zinc nitrate hexahydrate and indium nitrate hydrate solutions in ethylene glycol using sol-gel technique. The In content in the film was varied (0, 2, 10, 20, 40, 75 and 100 atom %). Films were prepared by spin coating of the liquid precursors followed by thermal decomposition at 400° C after each layer. According to X-ray diffraction (XRD) measurements, the pure ZnO and pure InO films (0 and at 100 % In) were crystalline as-deposited. The crystallinity was suppressed in mixed compositions such that the films with compositions between 10 and 75 at % were amorphous. All the films were transparent with the transmission cut-off frequency near 400 nm, which is characteristic of TCO materials. All as-deposited films were conductive with 0 and 100 atom % In having the lowest resistivities. The resistivity of all compositions were improved by post-deposition reducing anneal in pure Ar at 300° C. The lowest resistivity of 0.2 Ωcm was obtained for the pure ZnO after Ar anneal. It was two-orders of magnitude higher than reported in the literature for the In-doped ZnO, which was attributed to the low processing temperature. The resistivities of as-deposited and annealed in Ar films were increased by consequent air anneal at 300° C.

  18. Laser-Induced Thermal-Mechanical Damage Characteristics of Cleartran Multispectral Zinc Sulfide with Temperature-Dependent Properties

    NASA Astrophysics Data System (ADS)

    Peng, Yajing; Jiang, Yanxue; Yang, Yanqiang

    2015-01-01

    Laser-induced thermal-mechanical damage characteristics of window materials are the focus problems in laser weapon and anti-radiation reinforcement technology. Thermal-mechanical effects and damage characteristics are investigated for cleartran multispectral zinc sulfide (ZnS) thin film window materials irradiated by continuous laser using three-dimensional (3D) thermal-mechanical model. Some temperature-dependent parameters are introduced into the model. The temporal-spatial distributions of temperature and thermal stress are exhibited. The damage mechanism is analyzed. The influences of temperature effect of material parameters and laser intensity on the development of thermal stress and the damage characteristics are examined. The results show, the von Mises equivalent stress along the thickness direction is fluctuant, which originates from the transformation of principal stresses from compressive stress to tensile stress with the increase of depth from irradiated surface. The damage originates from the thermal stress but not the melting. The thermal stress is increased and the damage is accelerated by introducing the temperature effect of parameters or the increasing laser intensity.

  19. Inorganic-Organic Nanohybrid Materials of Layered Zinc Hydroxide Nitrate with Intercalated Salicylate: Preparation, Characterization and UV-Blocking Properties

    NASA Astrophysics Data System (ADS)

    Liu, Jiexiang; Zhang, Yongqing; Zhang, Xiaoguang

    2016-02-01

    Intercalation of salicylate (Sal) into layered zinc hydroxide nitrate (ZHN) nanohybrid materials was successfully synthesized by the coprecipitation method. The effect of pH, crystallization method, temperature and time of hydrothermal treatment on preparation was investigated in detail and compared. The products were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry and differential thermal analysis (TG-DTA), and scanning electron microscope (SEM). The results revealed that ZHN-Sal with pure phase and good crystallinity was obtained at pH = 6.0-6.5, 60∘C and 3h of temperature and time of hydrothermal treatment. The TG-DTA data indicated that the intercalated Sal had a high stability compared to the isolated. And the phases and compositions of the sample calcined at increasing temperatures were also identified by XRPD and FTIR techniques. Furthermore, ZHN-Sal exhibited an improved UV-blocking ability, showing it can be used as a potential alternative matrix for the UV blocker.

  20. Zinc and the modulation of redox homeostasis

    PubMed Central

    Oteiza, Patricia I.

    2012-01-01

    Zinc, a redox inactive metal, has been long viewed as a component of the antioxidant network, and growing evidence points to its involvement in redox-regulated signaling. These actions are exerted through several mechanisms based on the unique chemical and functional properties of zinc. Overall, zinc contributes to maintain the cell redox balance through different mechanisms including: i) the regulation of oxidant production and metal-induced oxidative damage; ii) the dynamic association of zinc with sulfur in protein cysteine clusters, from which the metal can be released by nitric oxide, peroxides, oxidized glutathione and other thiol oxidant species; iii) zinc-mediated induction of the zinc-binding protein metallothionein, which releases the metal under oxidative conditions and act per se scavenging oxidants; iv) the involvement of zinc in the regulation of glutathione metabolism and of the overall protein thiol redox status; and v) a direct or indirect regulation of redox signaling. Findings of oxidative stress, altered redox signaling, and associated cell/tissue disfunction in cell and animal models of zinc deficiency, stress the relevant role of zinc in the preservation of cell redox homeostasis. However, while the participation of zinc in antioxidant protection, redox sensing, and redox-regulated signaling is accepted, the involved molecules, targets and mechanisms are still partially known and the subject of active research. PMID:22960578

  1. Ozone depletion by hydrofluorocarbons

    NASA Astrophysics Data System (ADS)

    Hurwitz, Margaret M.; Fleming, Eric L.; Newman, Paul A.; Li, Feng; Mlawer, Eli; Cady-Pereira, Karen; Bailey, Roshelle

    2015-10-01

    Atmospheric concentrations of hydrofluorocarbons (HFCs) are projected to increase considerably in the coming decades. Chemistry climate model simulations forced by current projections show that HFCs will impact the global atmosphere increasingly through 2050. As strong radiative forcers, HFCs increase tropospheric and stratospheric temperatures, thereby enhancing ozone-destroying catalytic cycles and modifying the atmospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Simulations with the NASA Goddard Space Flight Center 2-D model show that HFC-125 is the most important contributor to HFC-related atmospheric change in 2050; its effects are comparable to the combined impacts of HFC-23, HFC-32, HFC-134a, and HFC-143a. Incorporating the interactions between chemistry, radiation, and dynamics, ozone depletion potentials (ODPs) for HFCs range from 0.39 × 10-3 to 30.0 × 10-3, approximately 100 times larger than previous ODP estimates which were based solely on chemical effects.

  2. The effect of ascorbic acid on the photophysical properties and photodynamic therapy activities of zinc phthalocyanine-single walled carbon nanotube conjugate on MCF-7 cancer cells.

    PubMed

    Ogbodu, Racheal O; Nyokong, Tebello

    2015-01-01

    Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π-π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents.

  3. Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

    PubMed

    Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

    2014-07-01

    We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed. PMID:24709542

  4. CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES: Phase Transition and Phonon Spectrum of Zinc-Blende Structure ZnX (X = S, Se, Te)

    NASA Astrophysics Data System (ADS)

    Tan, Jia-Jin; Ji, Guang-Fu; Chen, Xiang-Rong; Gou, Qing-Quan

    2010-06-01

    Calculations have been performed to investigate the pressure-induced solid-solid phase transitions and the mechanical stability for three zinc-blende II-VI semiconductor compounds: ZnS, ZnSe, ZnTe by ab initio plane-wave pseudopotential density functional theory (DFT). Using the generalized gradient approximation (GGA) for exchange and correlation in the scheme of Perdew-Wang 1991 (PW91), the ground state properties and equation of state are obtained, which are well consistent with the experimental data available and other calculations. On the basis of the forth-order Birch-Murnaghan equation of states, the transition pressures Pt are determined through the analysis of enthalpy variation with pressure. A linear-response approach is used to calculate the frequencies of the phonon dispersion. Finally, by the calculations of phonon frequencies, some thermodynamic properties such as the vibrational contribution to the Helmholtz free energy (F), enthalpy (H), entropy (S), and the heat capacity (CV) are also successfully obtained.

  5. Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

    PubMed

    Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

    2014-07-01

    We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed.

  6. The effect of ascorbic acid on the photophysical properties and photodynamic therapy activities of zinc phthalocyanine-single walled carbon nanotube conjugate on MCF-7 cancer cells.

    PubMed

    Ogbodu, Racheal O; Nyokong, Tebello

    2015-01-01

    Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π-π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents. PMID:26135538

  7. Influence of temperature on the electric, dielectric and AC conductivity properties of nano-crystalline zinc substituted cobalt ferrite synthesized by solution combustion technique

    NASA Astrophysics Data System (ADS)

    Rani, Ritu; Kumar, Gagan; Batoo, Khalid M.; Singh, M.

    2014-06-01

    Cobalt-zinc nanoferrites with formulae Co ZnFeO, where x = 0.0, 0.1, 0.2 and 0.3, have been synthesized by solution combustion technique. The variation of DC resistivity with temperature shows the semiconducting behavior of all nanoferrites. The dielectric properties such as dielectric constant (') and dielectric loss tangent (tan are investigated as a function of temperature and frequency. Dielectric constant and loss tangent are found to be increasing with an increase in temperature while with an increase in frequency both, ' and tan , are found to be decreasing. The dielectric properties have been explained on the basis of space charge polarization according to Maxwell-Wagner's two-layer model and the hopping of charge between Fe and Fe. Further, a very high value of dielectric constant and a low value of tan are the prime achievements of the present work. The AC electrical conductivity ( is studied as a function of temperature as well as frequency and is observed to be increasing with the increase in temperature and frequency.

  8. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES Phonon States and Dispersive Spectra of Polar Optical Phonons in Quasi-One-Dimensional Nanowires of Wurtzite ZnO and Zinc-Blend MgO Semiconductors

    NASA Astrophysics Data System (ADS)

    Zhang, Li

    2011-01-01

    Within the framework of the macroscopic dielectric continuum model and Loudon's uniaxial crystal model, the phonon modes of a wurtzite/zinc-blende one-dimensional (1D) cylindrical nanowire (NW) are derived and studied. The analytical phonon states of phonon modes are given. It is found that there exist two types of polar phonon modes, i.e. interface optical (IO) phonon modes and the quasi-confined (QC) phonon modes existing in 1D wurtzite/zinc-blende NWs. Via the standard procedure of field quantization, the Fröhlich electron-phonon interaction Hamiltonians are obtained. Numerical calculations of dispersive behavior of these phonon modes on a wurtzite/zinc-blende ZnO/MgO NW are performed. The frequency ranges of the IO and QC phonon modes of the ZnO/MgO NWs are analyzed and discussed. It is found that the IO modes only exist in one frequency range, while QC modes may appear in three frequency ranges. The dispersive properties of the IO and QC modes on the free wave-number kz and the azimuthal quantum number m are discussed. The analytical Hamiltonians of electron-phonon interaction obtained here are quite useful for further investigating phonon influence on optoelectronics properties of wurtzite/zinc-blende 1D NW structures.

  9. CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: Study on the dose rate upset effect of partially depleted silicon-on-insulator static random access memory

    NASA Astrophysics Data System (ADS)

    Zhao, Fa-Zhan; Liu, Meng-Xin; Guo, Tian-Lei; Liu, Gang; Hai, Chao-He; Han, Zheng-Sheng; Yang, Shan-Chao; Li, Rui-Bin; Lin, Dong-Sheng; Chen, Wei

    2008-12-01

    This paper implements the study on the Dose Rate Upset effect of PDSOI SRAM (Partially Depleted Silicon-On-Insulator Static Random Access Memory) with the Qiangguang-I accelerator in Northwest Institute of Nuclear Technology. The SRAM (Static Random Access Memory) chips are developed by the Institute of Microelectronics of Chinese Academy of Sciences. It uses the full address test mode to determine the upset mechanisms. A specified address test is taken in the same time. The test results indicate that the upset threshold of the PDSOI SRAM is about 1×108 Gy(Si)/s. However, there are a few bits upset when the dose rate reaches up to 1.58 × 109 Gy(Si)/s. The SRAM circuit can still work after the high level γ ray pulse. Finally, the upset mechanism is determined to be the rail span collapse by comparing the critical charge with the collected charge after γ ray pulse. The physical locations of upset cells are plotted in the layout of the SRAM to investigate the layout defect. Then, some layout optimizations are made to improve the dose rate hardened performance of the PDSOI SRAM.

  10. Electrical Properties and Reliability Analysis of Solution-Processed Indium Tin Zinc Oxide Thin Film Transistors with O2-Plasma Treatment.

    PubMed

    Ko, Sun Wook; Kim, Soon Kon; Kim, Jong Min; Cho, Jae Hee; Park, Hyoung Sun; Choi, Byoung Deog

    2015-10-01

    In this paper, we report the effects of O2-plasma treatment on the reliability and electrical properties of indium tin zinc oxide (ITZO) films. Excellent electrical properties, including a saturation mobility (μsat) of ~20.2 cm2/V · s, a threshold voltage (VTH) of ~-6.8 V, a sub-threshold swing (S.S) of ~0.956 V/decade, and an on/off current ratio (ION/OFF) of ~10(5) can be found with a molarity of 0.4 M and ratio of In:Zn:Sn = 2:1:2. Following O2-plasma treatment, it was confirmed that the electrical properties of the ITZO films are improved when compared to the untreated films. The devices showed a decreased S.S of ~0.51 V/decade, while the VTH and ION/OFF tended to increase. To determine the reliability of a-ITZO TFTs, we analyzed the electrical characteristics according to gate bias stress, VG,stress = 10 V for 4000 s. Improved reliability was confirmed when compared with the variation in threshold voltage prior to O2-plasma treatment, most likely stemming from a smooth surface on the active layer as a result of O2-plasma treatment. We were able to obtain a solution a-ITZO film transmittance of 92% in the visible light region (400~700 nm). These results show that a-ITZO TFTs fabricated via solution process with optimized molar ratio exhibit good electrical properties. a-ITZO films fabricated via spin-coating are a visible alternative to those fabricated via high-cost sputtering methods, and are applicable in flexible and transparent electronics. PMID:26726354

  11. Investigations on spectroscopic properties of Dy3+ doped zinc telluro-fluoroborate glasses for laser and white LED applications

    NASA Astrophysics Data System (ADS)

    Suthanthirakumar, P.; Marimuthu, K.

    2016-12-01

    A new series of Zinc telluro-fluoroborate glasses (ZTFB) doped with Dy3+ ions with the chemical composition (30-x) B2O3 + 30TeO2 + 16ZnO + 10ZnF2 + 7CaF2 + 7BaF2 + xDy2O3 (where x = 0.05, 0.1, 0.25, 0.5, 1 and 2 in wt%) have been synthesized by the conventional melt quenching technique and the prepared glass samples were characterized through XRD, FTIR, UV-Vis-NIR optical absorption, photoluminescence and decay spectral measurements. The XRD patterns have been recorded to confirm the amorphous nature. The FTIR spectral measurements were carried out to identify the functional groups present in the title glasses. From the energy band positions of the absorption spectra, bonding parameters (βbar and δ) have been calculated to identify the covalent/ionic nature of the metal-ligand bond present in the prepared glasses. The Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) have been calculated from the oscillator strengths of the different absorption bands to understand the nature of the ligand environment around the Dy3+ ions. The radiative parameters such as transition probability (A), stimulated emission cross-section (σPE), radiative lifetime (τR) and branching ratios (βR) corresponding to the 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, and 4F9/2 → 6H11/2 emission transitions have been determined using JO parameters and the refractive index values. The CIE chromaticity coordinates were calculated from the luminescence spectra to explore the dominant emission colour of the title glasses and the obtained results were discussed in detail and reported.

  12. Combined effect of demagnetizing field and induced magnetic anisotropy on the magnetic properties of manganese-zinc ferrite composites

    NASA Astrophysics Data System (ADS)

    Babayan, V.; Kazantseva, N. E.; Moučka, R.; Sapurina, I.; Spivak, Yu. M.; Moshnikov, V. A.

    2012-01-01

    This work is devoted to the analysis of factors responsible for the high-frequency shift of the complex permeability (μ*) dispersion region in polymer composites of manganese-zinc (MnZn) ferrite, as well as to the increase in their thermomagnetic stability. The magnetic spectra of the ferrite and its composites with polyurethane (MnZn-PU) and polyaniline (MnZn-PANI) are measured in the frequency range from 1 MHz to 3 GHz in a longitudinal magnetization field of up to 700 Ое and in the temperature interval from -20 °С to +150 °С. The approximation of the magnetic spectra by a model, which takes into account the role of domain wall motion and magnetization rotation, allows one to determine the specific contribution of resonance processes associated with domain wall motion and the natural ferromagnetic resonance to the μ*. It is established that, at high frequencies, the μ* of the MnZn ferrite is determined solely by magnetization rotation, which occurs in the region of natural ferromagnetic resonance when the ferrite is in the “single domain” state. In the polymer composites of the MnZn ferrite, the high-frequency permeability is also determined mainly by the magnetization rotation; however, up to high values of magnetizing fields, there is a contribution of domain wall motion, thus the “single domain” state in ferrite is not reached. The frequency and temperature dependence of μ* in polymer composites are governed by demagnetizing field and the induced magnetic anisotropy. The contribution of the induced magnetic anisotropy is crucial for MnZn-PANI. It is attributed to the elastic stresses that arise due to the domain wall pinning by a polyaniline film adsorbed on the surface of the ferrite during in-situ polymerization.

  13. A 3D porous zinc MOF constructed from a flexible tripodal ligand: Synthesis, structure, and photoluminescence property

    SciTech Connect

    Wen Lili; Wang Dong'e; Wang Chenggang; Wang Feng; Li Dongfeng Deng Kejian

    2009-03-15

    A new metal-organic framework, [Zn{sub 5}(trencba){sub 2}(OH){sub 2}Cl{sub 2}.4H{sub 2}O] (1) [H{sub 3}trencba=N,N,N',N',N'',N''-tris[(4-carboxylate-2-yl)methyl]-tris (2-aminoethyl)amine], constructed from a flexible tripodal ligand based on C{sub 3} symmetric tris(2-aminoethyl)amine, has been synthesized hydrothermally and characterized by elemental analysis, IR, TG, XRD and single-crystal X-ray diffraction analysis. Compound 1 contains an unprecedented linear penta-nuclear zinc cluster fragment. Each ligand links four penta-nuclear fragments, and every fragment links eight ligands to generate a three-dimensional non-interpenetrated porous framework. The uncoordinated water molecules were observed trapped in the void pores. Compound 1 represents the first example of (6,8)-connected 3D bi-nodal framework based on a single kind of organic ligand. The photoluminescence measurements showed that complex 1 exhibits relatively stronger blue emissions at room temperature than that of the ligand. - Graphical abstract: The MOF [Zn{sub 5}(trencba){sub 2}(OH){sub 2}Cl{sub 2}.4H{sub 2}O] (H{sub 3}trencba=N,N,N',N',N',N'-tris[(4-carboxylate-2-yl)methyl]-tris (2-aminoethyl)amine) reveals a (6,8)-connected bi-nodal three-dimensional porous framework with unprecedented penta-nuclear fragment, which appears to be a good candidate of hybrid inorganic-organic photoactive materials.

  14. The magnetic properties of plasma-sprayed thick-film manganese zinc ferrite (MZF) and nickel iron alloy (Permalloy) composites

    SciTech Connect

    Liang, S.; Gambino, R. J.; Sampath, S.; Raja, M. M.

    2006-04-15

    MnZn ferrite/Permalloy composites have potential in high frequency magnetic applications and can be made into thick-film devices by air plasma spray. The as-sprayed composites have lower saturation magnetization than the starting powder. After annealing below 600 deg. C, the magnetic properties and electrical resistivity improve significantly. The changes in magnetic and electrical properties were correlated to structural changes and studied by x-ray-diffraction analysis, vibrating-sample magnetometer measurements, and microstructural analysis.

  15. Accelerated bone ingrowth by local delivery of Zinc from bioactive glass: oxidative stress status, mechanical property, and microarchitectural characterization in an ovariectomized rat model

    PubMed Central

    Samira, Jbahi; Saoudi, Monji; Abdelmajid, Kabir; Hassane, Oudadesse; Treq, Rebai; Hafed, Efeki; Abdelfatteh, Elfeki; Hassib, Keskes

    2015-01-01

    Background Synthetic bone graft substitutes such as bioactive glass (BG) material are developed in order to achieve successful bone regeneration. Zn plays an important role in the proper bone growth, development, and maintenance of healthy bones. Aims This study aims to evaluate in vivo the performance therapy of zinc-doped bioactive glass (BG-Zn) and its applications in biomedicine. Methods Female Wistar rats were ovariectomized. BG and BG-Zn were implanted in the femoral condyles of Wistar rats and compared to that of control group. Grafted bone tissues were carefully removed to evaluate the oxidative stress status, histomorphometric profile, mechanical property, and mineral bone distribution by using inductively coupled plasma optical emission spectrometry. Results A significant decrease of thiobarbituric acid–reactive substances was observed after BG-Zn implantation. Superoxide dismutase, catalase (CAT), and glutathione peroxidase (GPx) activities significantly increased in ovariectomized group implanted with Zinc-doped bioactive glass (OVX-BG-Zn) as compared to ovariectomized group implanted with bioactive glass (OVX-BG). An improved mechanical property was noticed in contact of OVX-BG-Zn (39±6 HV) when compared with that of OVX-BG group (26±9 HV). After 90 days of implantation, the histomorphometric analysis showed that trabecular thickness (Tb.Th) and trabecular number (Tb.N) were significantly increased with 28 and 24%, respectively, in treated rats of OVX-BG-Zn group as compared to those of OVX-BG groups. Trabecular separation (Tb.Sp) and trabecular bone pattern factor (TBPf) were significantly decreased in OVX-BG-Zn group with 29.5 and 54% when compared with those of OVX-BG rat groups. On the other hand, a rise in Ca and P ion concentrations in the implanted microenvironment was shown and lead to the formation/deposition of Ca-P phases. The ratio of pyridinoline [Pyr] to dihydroxylysinonorleucine [DHLNL] cross-links was normalized to the control level

  16. Mechanical properties and in vitro cellular behavior of zinc-containing nano-bioactive glass doped biphasic calcium phosphate bone substitutes.

    PubMed

    Badr-Mohammadi, Mohammad-Reza; Hesaraki, Saeed; Zamanian, Ali

    2014-01-01

    In the present study, different amounts (0.5-5 wt%) of a sol gel-derived zinc-containing nano-bioactive glass (NBG-Zn) powder were added to biphasic calcium phosphate (BCP). The mixtures were sintered at 1,100-1,300 °C and physical characteristics, mechanical properties, phase composition and morphology of them were studied. The samples were also soaked in human blood plasma for 15 days to evaluate variations in their surface morphologies. Rat calvarium-derived osteoblastic cells were seeded on tops of various samples and cell adhesion, proliferation, and alkaline phosphatase activity were evaluated at different culturing periods. The maximum bending strength (62 MPa) was obtained for BCP containing 0.5 wt% NBG-Zn at temperature 1,200 °C. This value was approximately 80% higher than that of pure BCP. The bending strength failed when both sintering temperature and amount of added NBG-Zn increased. At 1,100 °C, NBG-Zn additive did not change the phase composition of BCP. At temperatures 1,200 and 1,300 °C, both alpha-tricalcium calcium phosphate (α-TCP) and beta-tricalcium phosphate (β-TCP and) phases were detected. However, adding higher amount of NBG-Zn to BCP resulted in elevation of β-TCP at 1,200 °C and progression of α-TCP at 1,300 °C. Based on the microscopic observations, adding 0.5 wt% NBG-Zn to BCP led to disappearance of grain boundaries, reduction of micropores and formation of a monolithic microstructure. No calcium phosphate precipitation was observed on sample surfaces after soaking in blood plasma, but some pores were produced by phase dissolution. The size and volume of these pores were directly proportional to NBG-Zn content. Based on the cell studies, both BCP and NBG-Zn-added BCP samples supported attachment and proliferation of osteoblasts, but higher alkaline phosphatase enzyme was synthesized within the cells cultured on NBG-Zn-added BCP. Overall, biphasic calcium phosphate materials with improved mechanical and biological properties

  17. Effect of platinum-nanodendrite modification on the glucose-sensing properties of a zinc-oxide-nanorod electrode

    NASA Astrophysics Data System (ADS)

    Abdul Razak, Khairunisak; Neoh, Soo Huan; Ridhuan, N. S.; Mohamad Nor, Noorhashimah

    2016-09-01

    The properties of ZnO nanorods (ZnONRs) decorated with platinum nanodendrites (PtNDs) were studied. Various sizes of PtNDs were synthesized and spin coated onto ZnONRs, which were grown on indium-titanium-oxide (ITO) substrates through a low-temperature hydrothermal method. Scanning electron microscopy and X-ray diffraction analyses were conducted to analyze the morphology and structural properties of the electrodes. The effects of PtND size, glucose concentration, and Nafion amount on glucose-sensing properties were investigated. The glucose-sensing properties of electrodes with immobilized glucose oxidase (GOx) were measured using cyclic voltammetry. The bio-electrochemical properties of Nafion/GOx/42 nm PtNDs/ZnONRs/ITO glucose sensor was observed with linear range within 1-18 mM, with a sensitivity value of 5.85 μA/mM and a limit of detection of 1.56 mM. The results of this study indicate that PtNDs/ZnONRs/ITO has potential in glucose sensor applications.

  18. Depletion potential in the infinite dilution limit

    NASA Astrophysics Data System (ADS)

    Yuste, Santos Bravo; Santos, Andrés; López de Haro, Mariano

    2008-04-01

    The depletion force and depletion potential between two in principle unequal "big" hard spheres embedded in a multicomponent mixture of "small" hard spheres are computed using the rational function approximation method for the structural properties of hard-sphere mixtures [S. B. Yuste, A. Santos, and M. López de Haro, J. Chem. Phys. 108, 3683 (1998)]. The cases of equal solute particles and of one big particle and a hard planar wall in a background monodisperse hard-sphere fluid are explicitly analyzed. An improvement over the performance of the Percus-Yevick theory and good agreement with available simulation results are found.

  19. Zinc Chelation Mediates the Lysosomal Disruption without Intracellular ROS Generation

    PubMed Central

    Matias, Andreza Cândido; Manieri, Tânia Maria; Cerchiaro, Giselle

    2016-01-01

    We report the molecular mechanism for zinc depletion caused by TPEN (N,N,N′,N′-Tetrakis(2-pyridylmethyl)ethylenediamine) in neuroblastoma cells. The activation of p38 MAP kinase and subsequently caspase 3 is not due to or followed by redox imbalance or ROS generation, though these are commonly observed in literature. We found that TPEN is not responsible for ROS generation and the mechanism involves essentially lysosomal disruption caused by intracellular zinc depletion. We also observed a modest activation of Bax and no changes in the Bcl-2 proteins. As a result, we suggest that TPEN causes intracellular zinc depletion which can influence the breakdown of lysosomes and cell death without ROS generation. PMID:27123155

  20. Production of nano zinc, zinc sulphide and nanocomplex of magnetite zinc oxide by Brevundimonas diminuta and Pseudomonas stutzeri.

    PubMed

    Mirhendi, Mansoureh; Emtiazi, Giti; Roghanian, Rasoul

    2013-12-01

    ZnO (Zincite) nanoparticle has many industrial applications and is mostly produced by chemical reactions, usually prepared by decomposition of zinc acetate or hot-injection and heating-up method. Synthesis of semi-conductor nanoparticles such as ZnS (Sphalerite) by ultrasonic was previously reported. In this work, high-zinc tolerant bacteria were isolated and used for nano zinc production. Among all isolated microorganisms, a gram negative bacterium which was identified as Brevundimonas diminuta could construct nano magnetite zinc oxide on bacterial surface with 22 nm in size and nano zinc with 48.29 nm in size. A piece of zinc metal was immersed in medium containing of pure culture of B. diminuta. Subsequently, a yellow-white biofilm was formed which was collected from the surface of zinc. It was dried at room temperature. The isolated biofilm was analysed by X-ray diffractometer. Interestingly, the yield of these particles was higher in the light, with pH 7 at 23°C. To the best of the authors knowledge, this is the first report about the production of nano zinc metal and nano zinc oxide that are stable and have anti-bacterial activities with magnetite property. Also ZnS (sized 12 nm) produced by Pseudomonas stutzeri, was studied by photoluminescence and fluorescent microscope.

  1. Tank depletion flow controller

    DOEpatents

    Georgeson, Melvin A.

    1976-10-26

    A flow control system includes two bubbler tubes installed at different levels within a tank containing such as radioactive liquid. As the tank is depleted, a differential pressure transmitter monitors pressure differences imparted by the two bubbler tubes at a remote, shielded location during uniform time intervals. At the end of each uniform interval, balance pots containing a dense liquid are valved together to equalize the pressures. The resulting sawtooth-shaped signal generated by the differential pressure transmitter is compared with a second sawtooth signal representing the desired flow rate during each time interval. Variations in the two signals are employed by a control instrument to regulate flow rate.

  2. Spectral and photophysical properties of zinc(II) complexes with alkylsubstituted derivatives of dipyrrolylmethene and their resistance to protolytic dissociation and photochemical destruction

    NASA Astrophysics Data System (ADS)

    Rumyantsev, E. V.; Aleshin, S. N.; Marfin, Yu. S.

    2013-02-01

    The spectral and photophysical properties of zinc(II) complexes with alkylsubstituted derivatives of dipyrrolylmethene, along with the kinetics of their protolytic dissociation and photochemical degradation in organic solvents of different natures, are studied by means of electronic absorption and fluorescence spectroscopy. It is found that protic solvents have the strongest effect on absorption spectra, while electron donors affect fluorescence spectra due to differences in the mechanisms of solvation for the ground and excited states of molecules. It is shown that the reaction product of the protolytic dissociation of complexes in benzene solutions of acetic acid is a protonated form of ligand. The observable and genuine rate constants of dissociation reactions are determined and activation parameters are calculated. A kinetic model of the process is proposed, and the regularities of the effect the nature of ligand has on the kinetics of dissociation are established. The photochemical degradation of compounds proceeds on monopyrrole products, the photolysis rate falls as the a degree of alkylation increases, and the nature of the substituent in the β-position of the ligand's pyrrole ring has a greater effect on the stability of a compound.

  3. The effect of the solution flow rate on the properties of zinc oxide (ZnO) thin films deposited by ultrasonic spray

    SciTech Connect

    Attaf, A. Benkhetta, Y.; Saidi, H.; Bouhdjar, A.; Bendjedidi, H.; Nouadji, M.; Lehraki, N.

    2015-03-30

    In this work, we used a system based on ultrasonic spray pyrolysis technique. By witch, we have deposited thin films of zinc oxide (ZnO) with the variation of solution flow rate from 50 ml / h to 150 ml / h, and set other parameters such as the concentration of the solution, the deposition time, substrate temperature and the nozzel -substrate distance. In order to study the influence of the solution flow rate on the properties of the films produced, we have several characterization techniques such as X-ray diffraction to determine the films structure, the scanning electron microscopy SEM for the morphology of the surfaces, EDS spectroscopy for the chemical composition, UV-Visible-Nir spectroscopy for determination the optical proprieties of thin films.The experimental results show that: the films have hexagonal structure at the type (wurtzite), the average size of grains varies from 20.11 to 32.45 nm, the transmittance of the films equals 80% in visible rang and the band gap is varied between 3.274 and 3.282 eV, when the solution flow rate increases from 50 to 150 ml/h.

  4. First-principles study of size-, surface- and mechanical strain-dependent electronic properties of wurtzite and zinc-blende InSb nanowires

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Xie, Zhong-Xiang; Yu, Xia; Wang, Hai-Bin; Deng, Yuan-Xiang; Ning, Feng

    2016-08-01

    Using first-principle calculations with density functional theory, we investigated the modification of electronic properties in zinc-blende (ZB) and wurtzite (WZ) InSb nanowires (NWs) grown along the [111] and [0001] directions for different size, different surface coverage and different mechanical strain. The results show that before the surface passivation, ZBNWs and WZNWs exhibit the metallic character and the semiconductor character, respectively. WZNWs show a crossover from a direct to an indirect as diameter decreases. After the surface passivation, both ZBNWs and WZNWs are found to be direct-gap character. The electronic band structure shows a significant response to changes in surface passivation with pseudo hydrogen and halogen. The band structure with mechanical strain is strongly dependent on the crystal orientation and the NW diameter. In ZBNWs, compressive strain induces the indirect band gap character, whereas tensile strain can not form it. WZNWs have various strain dependence in that both compressive and tensile strain make InSb show a direct band gap character. A brief analysis of these results is given.

  5. Effect of Aluminum concentration on structural and optical properties of DC reactive magnetron sputtered Zinc Aluminum Oxide thin films for transparent electrode applications

    NASA Astrophysics Data System (ADS)

    Kumar, B. Rajesh; Subba Rao, T.

    2012-11-01

    Zinc Aluminum Oxide(ZAO) thin films were deposited on glass substrates by DC reactive magnetron sputtering in an Ar+O2 gas mixture using commercial available Zn metal (99.99% purity) and Al (99.99% purity) targets of 2 inch diameter and 4 mm thickness. The films were characterized and the effect of aluminum (Al) concentration (2 at %-6 at %) on the structural and optical properties was studied. The average crystallite size obtained from Scherer formula is in the range of 32-44nm. Microstructural analysis using Scanning Electron Microscope (SEM) supplemented with EDS is carried out to find the grain size as well as to find the composition elemental data of prepared thin films. Optical study is performed to calculate the extinction coefficient (k), absorption coefficient (a), optical band gap (Eg) using transmission spectra obtained using UV-VIS-NIR spectrophotometer. There was widening of optical band gap with increasing aluminum concentration. ZAO film with low resistivity 3.2 × 10-4 cm and high transmittance of 80% is obtained for 3at% doped Al which is crucial for optoelectronic applications.

  6. An evaluation of the processing conditions, structure, and properties (biaxial flexural strength and antibacterial efficacy) of sintered strontium-zinc-silicate glass ceramics.

    PubMed

    Looney, Mark; Shea, Helen O'; Gunn, Lynda; Crowley, Dolores; Boyd, Daniel

    2013-05-01

    The use of artificial bone grafts has increased in order to satisfy a growing demand for bone replacement materials. Initial mechanical stability of synthetic bone grafts is very advantageous for certain clinical applications. Coupled with the advantage of mechanical strength, a material with inherent antibacterial properties would be very beneficial. A series of strontium-doped zinc silicate (Ca-Sr-Na-Zn-Si) glass ceramics have been characterized in terms of their crystalline structure, biaxial flexural strength and antibacterial efficacy based on the identification of optimum sintering conditions. All three glass ceramics, namely, BT110, BT111, and BT112 were found to be fully crystalline, with BT111 and BT112 comprising of biocompatible crystalline phases. The biaxial flexural strengths of the three glass ceramics ranged from 70 to 149 MPa and were shown to be superior to those of clinically established ceramics in dry conditions and following incubation in simulated physiological conditions. The bacteriostatic effect for each glass ceramic was also established, where BT112 showed an inhibitory effect against three of the most common bacteria found at implantation sites, namely, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. The results of the evaluation suggest that the materials studied offer advantages over current clinical materials and indicate the potential suitability of the glass ceramics as therapeutic bone grafts.

  7. Topological evolution and photoluminescent properties of a series of divalent zinc-based metal-organic frameworks tuned via ancillary ligating spacers

    NASA Astrophysics Data System (ADS)

    Lian, Xiao-Min; Zhao, Wen; Zhao, Xiao-Li

    2013-04-01

    The combination of divalent zinc ions, 4-(4-carboxybenzamido)benzoic acid and exo-bidendate bipyridine ligands gave rise to a series of new MOFs: [ZnL(bipy)]·DMF·H2O (1), [ZnL(bpe)]·1.5H2O (2), [ZnL(bpa)]·4H2O (3) and [ZnL(bpp)]·1.75H2O (4) (MOF=metal-organic framework, bipy=4,4'-bipyridine, bpe=trans-1,2-bis(4-pyridyl)ethylene, bpa=1,2-bis(4-pyridinyl)ethane, bpp=1,3-bis(4-pyridinyl)propane, H2L=4,4'-(carbonylimino)dibenzoic acid). Fine tune over the topology of the MOFs was achieved via systematically varying the geometric length of the second ligating bipyridine ligands. Single-crystal X-ray analysis reveals that complex 1 has a triply interpenetrated three-dimensional (3D) framework with elongated primitive cubic topology, whereas isostructural complexes 2 and 3 each possesses a 6-fold interpenetrated diamondiod 3D framework. Further expansion of the length of the bipyridine ligand to bpp leads to the formation of 4, which features an interesting entangled architecture of 2D→3D parallel polycatenation. In addition, the thermogravimetric analyses and solid-state photoluminescent properties of the selected complexes are investigated.

  8. The effect of nano-SiO 2 on the magnetic properties of the low power loss manganese-zinc ferrites

    NASA Astrophysics Data System (ADS)

    Nie, Jianhu; Li, Haihua; Feng, Zekun; He, Huahui

    2003-09-01

    The effect of the addition of nano-SiO 2 on the power losses in the manganese-zinc ferrites has been investigated by measuring the magnetic properties and observing the grain boundary structures. The powders of Mn 0.72Zn 0.21Fe 2.07O 4 composition were prepared by using a conventional ceramic powder processing technique. Toroidal cores were sintered at 1340°C for 4 h using a tube furnace with atmosphere controlled by using the equation for equilibrium oxygen partial pressure. The microstructure of grain boundary was observed by AES and SEM. It has been found that the grain boundaries resistivity and magnetic loss are greatly dependent upon the content of nano-SiO 2. There is an optimum content of nano-SiO 2 to produce uniform grain structure and low magnetic loss. The eddy current losses were reduced by the addition of nano-SiO 2. These losses are thought to originate from the additive effect of Si atoms, which are enriched in grain boundaries to form a high resistivity layer and prevent Ca and Nb atoms being incorporated with the spinel lattice.

  9. Antituberculosis nanodelivery system with controlled-release properties based on para-amino salicylate–zinc aluminum-layered double-hydroxide nanocomposites

    PubMed Central

    Saifullah, Bullo; Hussein, Mohd Zobir; Hussein-Al-Ali, Samer Hasan; Arulselvan, Palanisamy; Fakurazi, Sharida

    2013-01-01

    We report the intercalation and characterization of para-amino salicylic acid (PASA) into zinc/aluminum-layered double hydroxides (ZLDHs) by two methods, direct and indirect, to form nanocomposites: PASA nanocomposite prepared by a direct method (PASA-D) and PASA nanocomposite prepared by an indirect method (PASA-I). Powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis revealed that the PASA drugs were accommodated within the ZLDH interlayers. The anions of the drug were accommodated as an alternate monolayer (along the long-axis orientation) between ZLDH interlayers. Drug loading was estimated to be 22.8% and 16.6% for PASA-D and PASA-I, respectively. The in vitro release properties of the drug were investigated in physiological simulated phosphate-buffered saline solution of pH 7.4 and 4.8. The release followed the pseudo-second-order model for both nanocomposites. Cell viability (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assays) was assessed against normal human lung fibroblast MRC-5 and 3T3 mouse fibroblast cells at 24, 48, and 72 hours. The results showed that the nanocomposite formulations did not possess any cytotoxicity, at least up to 72 hours. PMID:24255593

  10. Improvement in the optical and electrical properties of Ga-doped zinc-oxide films by using nano-imprinted pattern arrays and post-annealing

    NASA Astrophysics Data System (ADS)

    Lee, Su Yeon; Lee, Seong Eui; Lee, Hee Chul; Lee, Ho Nyun; Kim, Hyun Jong

    2015-01-01

    The effects of nano-imprinted arrays and post-annealing on the optical and the electrical properties of sputtered Ga-doped zinc-oxide (GZO) films were intensively investigated to develop suitable electrodes for photonic applications. We fabricated nano-structures with a GZO circular pattern with a diameter of 250 nm by using UV nano-imprinting lithography and the lift-off process. The nano-structured GZO/glass substrate showed a high optical transmittance of 91.0% at a wavelength of 550 nm, which was increased by about 2.2% compared to that of unprocessed GZO/glass. Then nano-structured GZO/glass substrate was rapidly annealed under different conditions to acquire a high optical transmittance and a low resistivity. The optimized nano-structured GZO film post-annealed at 400 °C showed the highest optical transmittance of 92.0% and an improved resistivity of 1.3 × 10-3 Ω·cm.

  11. Identification of “safe harbor” loci in indica rice genome by harnessing the property of zinc-finger nucleases to induce DNA damage and repair

    PubMed Central

    Cantos, Christian; Francisco, Perigio; Trijatmiko, Kurniawan R.; Slamet-Loedin, Inez; Chadha-Mohanty, Prabhjit K.

    2014-01-01

    Zinc-finger nucleases (ZFNs) have proved to be successful tools for targeted genome manipulation in several organisms. Their main property is the induction of double-strand breaks (DSBs) at specific sites, which are further repaired through homologous recombination (HR) or non-homologous end joining (NHEJ). However, for the appropriate integration of genes at specific chromosomal locations, proper sites for gene integration need to be identified. These regions, hereby named safe harbor loci, must be localized in non-coding regions and possess high gene expression. In the present study, three different ZFN constructs (pZFN1, pZFN2, pZFN3), harboring β-glucuronidase (GUS) as a reporter gene, were used to identify safe harbor loci on rice chromosomes. The constructs were delivered into IR64 rice by using an improved Agrobacterium-mediated transformation protocol, based on the use of immature embryos. Gene expression was measured by histochemical GUS activity and the flanking regions were determined through thermal-asymmetric interlaced polymerase chain reaction (TAIL PCR). Following sequencing, 28 regions were identified as putative sites for safe integration, but only one was localized in a non-coding region and also possessed high GUS expression. These findings have significant applicability to create crops with new and valuable traits, since the site can be subsequently used to stably introduce one or more genes in a targeted manner. PMID:25018764

  12. Studies on the structural and optical properties of zinc oxide nanobushes and Co-doped ZnO self-aggregated nanorods synthesized by simple thermal decomposition route

    SciTech Connect

    Freedsman, Joseph J.; Kennedy, L. John; Kumar, R. Thinesh; Sekaran, G.; Vijaya, J. Judith

    2010-10-15

    Pure and Co-doped zinc oxide nanomaterials were prepared by a simple low temperature synthesis and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), diffused reflectance spectroscopy (DRS) and electron paramagnetic resonance (EPR) techniques. The results showed the formation of nanobushes that consists of several nanowires for pure ZnO and the nanorods formed by self-aggregation for Co-doped ZnO. The presence of Co{sup 2+} ions replacing some of the Zn{sup 2+} in the ZnO lattice was confirmed by EPR and DRS studies. The mechanism for the formation of self-aggregated and self-aligned ZnO rods after the incorporation of cobalt in the lattice by the building block units is discussed in this study. Morphological studies were carried out using SEM and HR-TEM, which supports the validity of the proposed mechanism for the formation of ZnO nanobushes and Co-doped ZnO nanorods. The synthesized nanomaterials were found to have good optoelectronic properties.

  13. Microbundles of zinc oxide nanorods: Assembly in ionic liquid [EMIM]{sup +}[BF{sub 4}]{sup -}, photoluminescence and photocatalytic properties

    SciTech Connect

    Wang Li; Xu Shenzhi; Li Huijun; Chang Lixian; Zhisu; Zeng Minghua; Wang Lina; Huang Yineng

    2011-03-15

    A simple, efficient and low-temperature approach for the assembly of hierarchical Zinc oxide (ZnO) microstructures in ionic liquid [EMIM]{sup +}[BF{sub 4}]{sup -} is reported. The as-obtained ZnO superstructures are composed of microbundles of nanorods from the center points, with the diameter and length in the range of 100-150 nm and 2-4 {mu}m, which have been characterized by X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence spectroscopy. The ZnO microstructures exhibit significant defect-related green-yellow emission and high photodegradation of dye Methyl Orange (5x10{sup -5} mol/L) under UV excitation within 80 min. -- Graphical abstract: Easy formation of microbundles of ZnO nanorods were accomplished in low temperature with [EMIM]{sup +}[BF{sub 4}]{sup -} (1-ethyl-3-methylimidazolium tetrafluoroborate) ionic liquid, which exhibit significant green-yellow photoluminescence property and high photodegradation of Methyl Orange dye. Display Omitted Research highlights: {yields} Ionic liquid assisted solid-state route was introduced into synthesis of ZnO nanorods. {yields} The distinctive microbundles ZnO nanorod assembles was evidenced by SEM and TEM. {yields} ZnO nano-material exhibited high efficiency in photodegradation of Methyl Orange.

  14. Characterization of Amorphous Zinc Tin Oxide Semiconductors

    SciTech Connect

    Rajachidambaram, Jaana Saranya; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Shutthanandan, V.; Varga, Tamas; Flynn, Brendan T.; Thevuthasan, Suntharampillai; Herman, Gregory S.

    2012-06-12

    Amorphous zinc tin oxide (ZTO) was investigated to determine the effect of deposition and post annealing conditions on film structure, composition, surface contamination, and thin film transistor (TFT) device performance. X-ray diffraction results indicated that the ZTO films remain amorphous even after annealing to 600 °C. We found that the bulk Zn:Sn ratio of the sputter deposited films were slightly tin rich compared to the composition of the ceramic sputter target, and there was a significant depletion of zinc at the surface. X-ray photoelectron spectroscopy also indicated that residual surface contamination depended strongly on the sample post-annealing conditions where water, carbonate and hydroxyl species were absorbed to the surface. Electrical characterization of ZTO films, using TFT test structures, indicated that mobilities as high as 17 cm2/Vs could be obtained for depletion mode devices.

  15. Production of zinc pellets

    DOEpatents

    Cooper, John F.

    1996-01-01

    Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries.

  16. Production of zinc pellets

    DOEpatents

    Cooper, J.F.

    1996-11-26

    Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.

  17. Microstructure, corrosion properties and bio-compatibility of calcium zinc phosphate coating on pure iron for biomedical application.

    PubMed

    Chen, Haiyan; Zhang, Erlin; Yang, Ke

    2014-01-01

    In order to improve the biocompatibility and the corrosion resistance in the initial stage of implantation, a phosphate (CaZn2(PO4)2·2H2O) coating was obtained on the surface of pure iron by a chemical reaction method. The anti-corrosion property, the blood compatibility and the cell toxicity of the coated pure iron specimens were investigated. The coating was composed of some fine phosphate crystals and the surface of coating was flat and dense enough. The electrochemical data indicated that the corrosion resistance of the coated pure iron was improved with the increase of phosphating time. When the specimen was phosphated for 30min, the corrosion resistance (Rp) increased to 8006 Ω. Compared with that of the naked pure iron, the anti-hemolysis property and cell compatibility of the coated specimen was improved significantly, while the anti-coagulant property became slightly worse due to the existence of element calcium. It was thought that phosphating treatment might be an effective method to improve the biocompatibility of pure iron for biomedical application.

  18. Putting the pieces into place: Properties of intact zinc metallothionein 1A determined from interaction of its isolated domains with carbonic anhydrase.

    PubMed

    Pinter, Tyler B J; Stillman, Martin J

    2015-11-01

    Mammalian metallothioneins (MTs) bind up to seven Zn(2+) using a large number of cysteine residues relative to their small size and can act as zinc-chaperones. In metal-saturated Zn7-MTs, the seven zinc ions are co-ordinated tetrahedrally into two distinct clusters separated by a linker; the N-terminal β-domain [(Zn3Cys9)(3-)] and C-terminal α-domain [(Zn4Cys11)(3-)]. We report on the competitive zinc metalation of apo-carbonic anhydrase [CA; metal-free CA (apo-CA)] in the presence of apo-metallothionein 1A domain fragments to identify domain specific determinants of zinc binding and zinc donation in the intact two-domain Znn-βαMT1A (human metallothionein 1A isoform; n=0-7). The apo-CA is shown to compete effectively only with Zn2-3-βMT and Zn4-αMT. Detailed modelling of the ESI mass spectral data have revealed the zinc-binding affinities of each of the zinc-binding sites in the two isolated fragments. The three calculated equilibrium zinc affinities [log(KF)] of the isolated β-domain were: 12.2, 11.7 and 11.4 and the four isolated α-domain affinities were: 13.5, 13.2, 12.7 and 12.6. These data provide guidance in identification of the location of the strongest-bound and weakest-bound zinc in the intact two-domain Zn7βαMT. The β-domain has the weakest zinc-binding site and this is where zinc ions are donated from in the Zn7-βαMT. The α-domain with the highest affinity binds the first zinc, which we propose leads to an unscrambling of the cysteine ligands from the apo-peptide bundle. We propose that stabilization of the intact Zn6-MT and Zn7-MT, relative to that of the sum of the separated fragments, is due to the availability of additional cysteine ligand orientations (through interdomain interactions) to support the clustered structures.

  19. First-principles study on the electronic and optical properties of Si and Al co-doped zinc oxide for solar cell devices

    NASA Astrophysics Data System (ADS)

    Abbassi, A.; El Amrani, A.; Ez-Zahraouy, H.; Benyoussef, A.; El Amraoui, Y.

    2016-06-01

    Electronic and optical properties of co-doped zinc oxide ZnO with silicon (Si) and aluminum (Al), in Zn1-2 x Si x Al x O (0 ≤ x ≤ 0.0625) original structure forms, are investigated by the first-principles calculations based on the density functional theory (DFT). The optical constants and dielectric functions are investigated with the full-potential linearized augmented plane wave (FP-LAPW) method and the generalized gradient approximation (GGA) by WIEN2k package. The complex dielectric functions, refractive index and band gap of the pure as well as doped and co-doped ZnO were investigated, which are in good agreement with the available experimental results for the undoped ZnO. Thus, the maximum optical transmittance of the co-doped ZnO of about 95 % was achieved; it is higher than that of pure ZnO. Thus, we showed for the Si-Al co-doped ZnO with x = 0.0315 that the optical transmittance can cover a larger range in the visible light region. In addition, an occurrence of important energy levels around Fermi levels was showed, which is mainly due to doping atoms that lead to an overlap between valence and conduction bands, and consequently to the significant conductor behavior of the Si-Al co-doped ZnO. The original Zn1-2 x Si x Al x O structure reveals promising optical and electronic properties, and it can be investigated as good candidates for practical uses as transparent and conducting electrodes in solar cell devices.

  20. Effects of nanoassembly on the optoelectronic properties of cadmium telluride - zinc oxide nanocomposite thin films for use in photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Beal, Russell Joseph

    Quantum-scale semiconductors embedded in an electrically-active matrix have the potential to improve photovoltaic (PV) device power conversion efficiencies by allowing the solar spectral absorption and photocarrier transport properties to be tuned through the control of short and long range structure. In the present work, the effects of phase assembly on quantum confinement effects and carrier transport were investigated in CdTe - ZnO nanocomposite thin films for use as a spectrally sensitized n-type heterojunction element. The nanocomposites were deposited via a dual-source, sequential radio-frequency (RF) sputter technique that offers the unique opportunity for in-situ control of the CdTe phase spatial distribution within the ZnO matrix. The manipulation of the spatial distribution of the CdTe nanophase allowed for variation in the electromagnetic coupling interactions between semiconductor domains and accompanying changes in the effective carrier confinement volume and associated spectral absorption properties. Deposition conditions favoring CdTe connectivity had a red shift in absorption energy onset in comparison to phase assemblies with a more isolated CdTe phase. While manipulating the absorption properties is of significant interest, the electronic behavior of the nanocomposite must also be considered. The continuity of both the matrix and the CdTe influenced the mobility pathways for carriers generated within their respective phases. Photoconductivity of the nanocomposite, dependent upon the combined influences of nanostructure-mediated optical absorption and carrier transport path, increased with an increased semiconductor nanoparticle number density along the applied field direction. Mobility of the carriers in the nanocomposite was further mediated by the interface between the ZnO and CdTe nanophases which acts as a source of carrier scattering centers. These effects were influenced by low temperature annealing of the nanocomposite which served to

  1. Zinc isotopic evidence for the origin of the Moon.

    PubMed

    Paniello, Randal C; Day, James M D; Moynier, Frédéric

    2012-10-18

    Volatile elements have a fundamental role in the evolution of planets. But how budgets of volatiles were set in planets, and the nature and extent of volatile-depletion of planetary bodies during the earliest stages of Solar System formation remain poorly understood. The Moon is considered to be volatile-depleted and so it has been predicted that volatile loss should have fractionated stable isotopes of moderately volatile elements. One such element, zinc, exhibits strong isotopic fractionation during volatilization in planetary rocks, but is hardly fractionated during terrestrial igneous processes, making it a powerful tracer of the volatile histories of planets. Here we present high-precision zinc isotopic and abundance data which show that lunar magmatic rocks are enriched in the heavy isotopes of zinc and have lower zinc concentrations than terrestrial or Martian igneous rocks. Conversely, Earth and Mars have broadly chondritic zinc isotopic compositions. We show that these variations represent large-scale evaporation of zinc, most probably in the aftermath of the Moon-forming event, rather than small-scale evaporation processes during volcanism. Our results therefore represent evidence for volatile depletion of the Moon through evaporation, and are consistent with a giant impact origin for the Earth and Moon. PMID:23075987

  2. Zinc isotopic evidence for the origin of the Moon.

    PubMed

    Paniello, Randal C; Day, James M D; Moynier, Frédéric

    2012-10-18

    Volatile elements have a fundamental role in the evolution of planets. But how budgets of volatiles were set in planets, and the nature and extent of volatile-depletion of planetary bodies during the earliest stages of Solar System formation remain poorly understood. The Moon is considered to be volatile-depleted and so it has been predicted that volatile loss should have fractionated stable isotopes of moderately volatile elements. One such element, zinc, exhibits strong isotopic fractionation during volatilization in planetary rocks, but is hardly fractionated during terrestrial igneous processes, making it a powerful tracer of the volatile histories of planets. Here we present high-precision zinc isotopic and abundance data which show that lunar magmatic rocks are enriched in the heavy isotopes of zinc and have lower zinc concentrations than terrestrial or Martian igneous rocks. Conversely, Earth and Mars have broadly chondritic zinc isotopic compositions. We show that these variations represent large-scale evaporation of zinc, most probably in the aftermath of the Moon-forming event, rather than small-scale evaporation processes during volcanism. Our results therefore represent evidence for volatile depletion of the Moon through evaporation, and are consistent with a giant impact origin for the Earth and Moon.

  3. Zinc isotopic evidence for the origin of the Moon

    NASA Astrophysics Data System (ADS)

    Paniello, Randal C.; Day, James M. D.; Moynier, Frédéric

    2012-10-01

    Volatile elements have a fundamental role in the evolution of planets. But how budgets of volatiles were set in planets, and the nature and extent of volatile-depletion of planetary bodies during the earliest stages of Solar System formation remain poorly understood. The Moon is considered to be volatile-depleted and so it has been predicted that volatile loss should have fractionated stable isotopes of moderately volatile elements. One such element, zinc, exhibits strong isotopic fractionation during volatilization in planetary rocks, but is hardly fractionated during terrestrial igneous processes, making it a powerful tracer of the volatile histories of planets. Here we present high-precision zinc isotopic and abundance data which show that lunar magmatic rocks are enriched in the heavy isotopes of zinc and have lower zinc concentrations than terrestrial or Martian igneous rocks. Conversely, Earth and Mars have broadly chondritic zinc isotopic compositions. We show that these variations represent large-scale evaporation of zinc, most probably in the aftermath of the Moon-forming event, rather than small-scale evaporation processes during volcanism. Our results therefore represent evidence for volatile depletion of the Moon through evaporation, and are consistent with a giant impact origin for the Earth and Moon.

  4. Effect of sulfurization time on the properties of copper zinc tin sulfide thin films grown by electrochemical deposition

    NASA Astrophysics Data System (ADS)

    Aldalbahi, Ali; Mkawi, E. M.; Ibrahim, K.; Farrukh, M. A.

    2016-09-01

    We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37–1.47 eV.

  5. Periodic density functional theory study of structural and electronic properties of single-walled zinc oxide and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Marana, Naiara L.; Albuquerque, Anderson R.; La Porta, Felipe A.; Longo, Elson; Sambrano, Julio R.

    2016-05-01

    Periodic density functional theory calculations with the B3LYP hybrid functional and all-electron Gaussian basis set were performed to simulate the structural and electronic properties as well as the strain and formation energies of single-walled ZnO nanotubes (SWZnONTs) and Carbon nanotubes (SWCNTs) with different chiralities as functions of their diameters. For all SWZnONTs, the band gap, strain energy, and formation energy converge to ~4.5 eV, 0.0 eV/atom, and 0.40 eV/atom, respectively. This result suggests that the nanotubes are formed more easily from the surface than from the bulk. For SWCNTs, the strain energy is always positive, while the formation energy is negative for armchair and zigzag nanotubes, therefore suggesting that these types of nanotubes can be preferentially formed from the bulk. The electronic properties of SWCNTs depend on the chirality; all armchair nanotubes are metallic, while zigzag and chiral nanotubes can be metallic or semiconducting, depending on the n and m vectors.

  6. Structural evolution and magnetic properties of nanocrystalline magnesium-zinc soft ferrites synthesized by glycine-nitrate combustion process

    NASA Astrophysics Data System (ADS)

    Hajarpour, S.; Honarbakhsh Raouf, A.; Gheisari, Kh.

    2014-08-01

    In this study, nanocrystalline Mg1-xZnxFe2O4 soft magnetic ferrites are synthesized by varying x from 0.0 to 0.6 with a step size of 0.1. A new combustion synthesis approach is taken using glycine as fuel and metal (Fe, Mg and Zn) nitrates as reactants. The effect of varying chemical composition, i.e. changing the parameter x, on the structural and magnetic properties is evaluated. X-ray diffraction results confirm that all samples crystallize in a spinel-type structure. Lattice parameter (a) is found to increase with the substitution of Zn2+ ions. The field emission scanning electron microscopy (FESEM) is used for morphological investigations. Magnetic properties of Mg1-xZnxFe2O4 ferrites are also evaluated by a vibrating sample magnetometer (VSM). It is found that the saturation magnetization increases as the Zn content goes up to x===0.4 and decreases afterwards. The change in saturation magnetization with Zn content is attributed to the variation of cation distribution in the spinel structure as chemical composition is modified.

  7. Effect of sulfurization time on the properties of copper zinc tin sulfide thin films grown by electrochemical deposition

    PubMed Central

    Aldalbahi, Ali; Mkawi, E. M.; Ibrahim, K.; Farrukh, M. A.

    2016-01-01

    We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37–1.47 eV. PMID:27600023

  8. Emissive bis-salicylaldiminato Schiff base ligands and their zinc(II) complexes: Synthesis, photophysical properties, mesomorphism and DFT studies

    NASA Astrophysics Data System (ADS)

    Paul, Manoj Kr.; Dilipkumar Singh, Y.; Bedamani Singh, N.; Sarkar, Utpal

    2015-02-01

    Bis-salicylaldiminato Schiff base ligands and their Zn(II) complexes derived from 2,3-Diaminomaleonitrile (DAMN) were synthesized. Their molecular structures, photophysical properties and mesogenic behaviors were investigated. The ligands and their Zn(II) complexes were characterized by using elemental analysis, FT-IR, 1H NMR and molar conductivity measurements. Photophysical properties of ligands and their Zn(II) complexes were investigated in different polar solvents by using UV-visible and fluorescence spectroscopic studies. Ligands emit green light whereas complexes emit orange light upon irradiation with UV-visible light. The liquid crystalline phases of ligands and their Zn(II) complexes were characterized by polarizing optical microscopy and differential scanning calorimetry. The ligand having longer 4-n-octadecyloxy chain (n = 18) displays columnar phase whereas the lower homologues (n = 16, 12) did not show mesophase. The Zn(II) complexes having 4-n-octadecyloxy end chain display smectic B like phase whereas other lower homologues are non mesogenic in nature. The thermal stability of the compounds were studied by using thermo gravimetric analysis. The density functional theory was carried out to obtain the stable molecular conformation, dipole moment, molecular orbitals and polarizability of the ligands and their Zn(II) complexes.

  9. Effect of sulfurization time on the properties of copper zinc tin sulfide thin films grown by electrochemical deposition.

    PubMed

    Aldalbahi, Ali; Mkawi, E M; Ibrahim, K; Farrukh, M A

    2016-01-01

    We report growth of quaternary Cu2 ZnSnS4 (CZTS) thin films prepared by the electrochemical deposition from salt precursors containing Cu (II), Zn (II) and Sn (IV) metals. The influence of different sulfurization times t (t = 75, 90, 105, and 120 min) on the structural, compositional, morphological, and optical properties, as well as on the electrical properties is studied. The films sulfurized 2 hours showed a prominent kesterite phase with a nearly stoichiometric composition. Samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Raman and UV-VIS-NIR spectrometer at different stages of work. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of phase-pure CZTS films. (FESEM) shows that compact and dense morphology and enhanced photo-sensitivity. STEM - EDS elemental map of CZTS cross-section confirms homogeneous distribution. From optical study, energy gap was enlarged with a changed sulfurization times in the range of 1.37-1.47 eV. PMID:27600023

  10. Transcriptional Regulation, Metal Binding Properties and Structure of Pden1597, an Unusual Zinc Transport Protein from Paracoccus denitrificans.

    PubMed

    Handali, Melody; Neupane, Durga P; Roychowdhury, Hridindu; Yukl, Erik T

    2015-05-01

    ATP-binding cassette (ABC) transporters of the cluster 9 family are ubiquitous among bacteria and essential for acquiring Zn(2+) and Mn(2+) from the environment or, in the case of pathogens, from the host. These rely on a substrate-binding protein (SBP) to coordinate the relevant metal with high affinity and specificity and subsequently release it to a membrane permease for translocation into the cytoplasm. Although a number of cluster 9 SBP structures have been determined, the structural attributes conferring Zn(2+) or Mn(2+) specificity remain ambiguous. Here we describe the gene expression profile, in vitro metal binding properties, and crystal structure of a new cluster 9 SBP from Paracoccus denitrificans we have called AztC. Although all of our results strongly indicate Zn(2+) over Mn(2+) specificity, the Zn(2+) ion is coordinated by a conserved Asp residue only observed to date as a metal ligand in Mn(2+)-specific SBPs. The unusual sequence properties of this protein are shared among close homologues, including members from the human pathogens Klebsiella pneumonia and Enterobacter aerogenes, and would seem to suggest a subclass of Zn(2+)-specific transporters among the cluster 9 family. In any case, the unusual coordination environment of AztC expands the already considerable range of those available to Zn(2+)-specific SBPs and highlights the presence of a His-rich loop as the most reliable indicator of Zn(2+) specificity.

  11. Transcriptional Regulation, Metal Binding Properties and Structure of Pden1597, an Unusual Zinc Transport Protein from Paracoccus denitrificans.

    PubMed

    Handali, Melody; Neupane, Durga P; Roychowdhury, Hridindu; Yukl, Erik T

    2015-05-01

    ATP-binding cassette (ABC) transporters of the cluster 9 family are ubiquitous among bacteria and essential for acquiring Zn(2+) and Mn(2+) from the environment or, in the case of pathogens, from the host. These rely on a substrate-binding protein (SBP) to coordinate the relevant metal with high affinity and specificity and subsequently release it to a membrane permease for translocation into the cytoplasm. Although a number of cluster 9 SBP structures have been determined, the structural attributes conferring Zn(2+) or Mn(2+) specificity remain ambiguous. Here we describe the gene expression profile, in vitro metal binding properties, and crystal structure of a new cluster 9 SBP from Paracoccus denitrificans we have called AztC. Although all of our results strongly indicate Zn(2+) over Mn(2+) specificity, the Zn(2+) ion is coordinated by a conserved Asp residue only observed to date as a metal ligand in Mn(2+)-specific SBPs. The unusual sequence properties of this protein are shared among close homologues, including members from the human pathogens Klebsiella pneumonia and Enterobacter aerogenes, and would seem to suggest a subclass of Zn(2+)-specific transporters among the cluster 9 family. In any case, the unusual coordination environment of AztC expands the already considerable range of those available to Zn(2+)-specific SBPs and highlights the presence of a His-rich loop as the most reliable indicator of Zn(2+) specificity. PMID:25787075

  12. Ozone Depletion by Hydrofluorocarbons

    NASA Astrophysics Data System (ADS)

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.

    2015-12-01

    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  13. Dietary phytate, zinc and hidden zinc deficiency.

    PubMed

    Sandstead, Harold H; Freeland-Graves, Jeanne H

    2014-10-01

    Epidemiological data suggest at least one in five humans are at risk of zinc deficiency. This is in large part because the phytate in cereals and legumes has not been removed during food preparation. Phytate, a potent indigestible ligand for zinc prevents it's absorption. Without knowledge of the frequency of consumption of foods rich in phytate, and foods rich in bioavailable zinc, the recognition of zinc deficiency early in the illness may be difficult. Plasma zinc is insensitive to early zinc deficiency. Serum ferritin concentration≤20μg/L is a potential indirect biomarker. Early effects of zinc deficiency are chemical, functional and may be "hidden". The clinical problem is illustrated by 2 studies that involved US Mexican-American children, and US premenopausal women. The children were consuming home diets that included traditional foods high in phytate. The premenopausal women were not eating red meat on a regular basis, and their consumption of phytate was mainly from bran breakfast cereals. In both studies the presence of zinc deficiency was proven by functional responses to controlled zinc treatment. In the children lean-mass, reasoning, and immunity were significantly affected. In the women memory, reasoning, and eye-hand coordination were significantly affected. A screening self-administered food frequency questionnaire for office might help caregiver's identify patients at risk of zinc deficiency.

  14. Electrical properties of Zinc-Tin diarsenide (ZnSnAs{sub 2}) irradiated with H{sup +} ions

    SciTech Connect

    Brudnyi, V. N. Vedernikova, T. V.

    2009-04-15

    The results of studying the electrical properties and isochronous annealing of p-ZnSnAs{sub 2} irradiated with H{sup +} ions (energy E = 5 MeV, dose D = 2 x 10{sup 16} cm{sup -2}) are reported. The limiting electrical characteristics of irradiated material (the Hall coefficient R{sub H} (D){sub lim} {approx} -4 x 10{sup 3} cm{sup 3} C{sup -1}, conductivity {sigma} (D){sub lim} {approx} 2.9 x 10{sup -2} {omega}{sup -1} cm{sup -1}, and the Fermi level position F{sub lim} {approx} 0.58 eV above the valence-band top at 300 K) are determined. The energy position of the 'neutral' point for the ZnSnAs{sub 2} compound is calculated.

  15. Effect of Sintering Temperature on the Structural and Dielectric Properties of Zinc Cadmium Ferrites Prepared by Egg-White Technique

    NASA Astrophysics Data System (ADS)

    Dar, M. Abdullah; Siddiqui, W. A.; Alam, M.

    The effect of cadmium substitution and sintering temperature on the microstructure and dielectric properties of nano ZnCdxFe2-xO4 ferrites (x=0.0, 0.05, 0.1, 0.2, 0.3 and 0.5) has been investigated and prepared by egg-white technique. Electrical conductivity and dielectric measurements have been analysed in the frequency range from 100 Hz to 10 MHz. The variation of the real (ɛ‧) and imaginary (ɛ″) part of dielectric constant, AC conductivity (σAC) and loss tangent (tan δ) with frequency has been studied. It follows the Maxwell-Wagner model based on the interfacial polarization in consonance with the Koop's phenomenological theory. It is found that the permittivity of ZnCdxFe2-xO4 ferrites improved and shows a maximum value (~9 × 103) at 100 Hz for the x=0.1 sample.

  16. Study of structural and optical properties of ZnAlQ5 (zinc aluminum quinolate) organic phosphor for OLED applications

    NASA Astrophysics Data System (ADS)

    Nagpure, I. M.; Painuly, Deepshikha; Rabanal, Maria Eugenia

    2016-05-01

    The various composition of ZnAlQ5 such as Zn1.5A10.5Q5, Zn1Al1Q5, Zn0.5Al1.5Q5 organic phosphors were prepared via simple cost effective co-precipitation method. The FTIR, SEM, photoluminescence analysis of the prepared phosphors were reported. ZnQ2 and AlQ3 were also prepared by similar method and their properties were compared with different composition of ZnAlQ5. The structural elucidation in the form of stretching frequencies of chemical bonds of the prepared phosphor was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The stretching frequency analysis confirms the formation of prepared phosphor materials. The SEM analysis shows the surface morphological behavior of prepared phosphor materials. Greenish photoluminescence were observed at 505 to 510 nm for the different composition of ZnAlQ5,in which Zn1.5Al0.5Q5 shows maximum luminescence intensity at 505 nm. PL emission of ZnQ2 was observed at 515 nm, while for AlQ3 at 520 nm. The blue shift of 10 nm was observed in Zn1.5A10.5Q5 due to modification of energy level due to presence of Zn2+ and Al3+. The enhancement in PL intensity was observed in Zn1.5A10.5Q5 compared to the other composition due to transfer of energy between Zn2+ and quinolate complex. Optical properties of the prepared materials were evaluated for possible applications in organic light emitting devices (OLED).

  17. Zinc and vegetarian diets.

    PubMed

    Saunders, Angela V; Craig, Winston J; Baines, Surinder K

    2013-08-19

    Well planned vegetarian diets can provide adequate amounts of zinc from plant sources. Vegetarians appear to adapt to lower zinc intakes by increased absorption and retention of zinc. Good sources of zinc for vegetarians include whole grains, tofu, tempeh, legumes, nuts and seeds, fortified breakfast cereals and dairy products. The inhibitory effects of phytate on absorption of zinc can be minimised by modern food-processing methods such as soaking, heating, sprouting, fermenting and leavening. Absorption of zinc can be improved by using yeast-based breads and sourdough breads, sprouts, and presoaked legumes. Studies show vegetarians have similar serum zinc concentrations to, and no greater risk of zinc deficiency than, non-vegetarians (despite differences in zinc intake).

  18. Transient neonatal zinc deficiency.

    PubMed

    Krieger, I; Alpern, B E; Cunnane, S C

    1986-06-01

    We report an infant who developed clinical manifestations of zinc deficiency during the first month of life although the diet was adequate for zinc and no other causes could be ascertained. The diagnosis was confirmed by low plasma-zinc concentrations and a positive response to zinc treatment. The fatty acid profile of plasma phospholipids was typical of zinc deficiency (ie, arachidonic acid was markedly decreased). The transient nature of this disorder was evident when no relapse occurred after cessation of zinc therapy and plasma-zinc and arachidonic acid concentrations remained normal. Several explanations for the development of transient neonatal zinc deficiency are offered. The observation demonstrates that occasional infants may have requirements for zinc that are beyond the intakes of the conventional RDA. PMID:3717070

  19. Fatigue of die cast zinc alloys

    SciTech Connect

    Schrems, K.K.; Dogan, O.N.; Goodwin, F.E.

    2006-04-01

    The rotating bending fatigue limit of die cast zinc alloy 2, alloy 3, alloy 5, AcuZinc 5, and ZA-8 were determined as a part of an on-going program by ILZRO into the mechanical properties of die cast zinc. The stress-life (S-N) curves of alloys 3, 5, AcuZinc 5, and ZA-8 were determined previously. This presentation reports the results of the S-N curve for Alloy 2 and the calculated fatigue limits for all five alloys. During the previous stress-life testing, the samples were stopped at 10 million cycles and the fatigue limit for alloy 3, alloy 5, and AcuZinc 5 appeared to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. This was further investigated in alloy 5 and ZA-8 by testing continuous cast bulk alloy 5 and ZA-8.

  20. Preparation of cobalt-zinc ferrite (Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) nanopowder via combustion method and investigation of its magnetic properties

    SciTech Connect

    Yousefi, M.H.; Manouchehri, S.; Arab, A.; Mozaffari, M.; Amiri, Gh. R.; Amighian, J.

    2010-12-15

    Research highlights: {yields} Cobalt-zinc ferrite was prepared by combustion method. {yields} Properties of the sample were characterized by several techniques. {yields} Curie temperature was determined to be 350 {sup o}C. -- Abstract: Cobalt-zinc ferrite (Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) was prepared by combustion method, using cobalt, zinc and iron nitrates. The crystallinity of the as-burnt powder was developed by annealing at 700 {sup o}C. Crystalline phase was investigated by XRD. Using Williamson-Hall method, the average crystallite sizes for nanoparticles were determined to be about 27 nm before and 37 nm after annealing, and residual stresses for annealed particles were omitted. The morphology of the annealed sample was investigated by TEM and the mean particle size was determined to be about 30 nm. The final stoichiometry of the sample after annealing showed good agreement with the initial stoichiometry using atomic absorption spectrometry. Magnetic properties of the annealed sample such as saturation magnetization, remanence magnetization, and coercivity measured at room temperature were 70 emu/g, 14 emu/g, and 270 Oe, respectively. The Curie temperature of the sample was determined to be 350 {sup o}C using AC-susceptibility technique.

  1. Examination of zinc oxide, copper chromium oxide, and copper scandium oxide properties for use in transparent electronics and chemical sensors

    NASA Astrophysics Data System (ADS)

    Sadik, Patrick

    Greater progress in the field of TCO (transparent oxide semiconductor) research has been hampered by a lack of availability of p-type candidates. Though the n-type TCO's are well documented and easily produced only one well documented oxide has spurred continued efforts at producing robust, p-type behavior, namely ZnO. Though p-ZnO has been produced, a coterminous research effort into improving the film qualities of lesser known naturally p-type TCO's could prove fruitful. Thus, this research has examined the thin film properties of two delafossites, CuCr1-xMgxO 2 and CuSc1-xMgxO2 as well as the surface properties of ZnO. The delafossites, CuCr1-xMgxO2 and CuSc 1-xMgxO2 have been shown to have the superlative properties of high conductivities (220 S cm-1 and 70 S cm-1) and high transparencies in 400 nm thick films of ˜40% and ˜80% throughout the visible spectrum. We have also been the first to describe a near band edge photo-luminescence in CuSc1-x MgxO2 for 0.00< x<0.03, opening the possibility of creating delafossite active layer light emitting diodes. The greatest challenge in creating viable pn-junctions between the delafossites and ZnO is preventing an in situ reaction between CuCr1-xMgxO 2 and ZnO that creates a (Mg/Cu)Cr2O4 spinel interface. We have found that a strategy of using a CuCr1-xMgxO 2/CuSc1-xMgxO2/ZnO on c-Al2O 3 in two ways may allow the growth of either a buffer/p/n or a p/i/n structure. Specifically, growing CuCrO2 at 700°C as a 100 nm nucleation layer followed by a 750°C growth of CuSc1-xMg xO2 and a 400°C growth of ZnO secures an epitaxial growth for the entire structure despite large lattice mismatches between c-Al2O3/CuCrO2 (8.7%) and CuCrO 2/CuScO2 (7.7%). This combined research takes the first steps in making robust pn-heterojunctions possible. Also, in an effort to progress an understanding of the surface chemistry of ZnO we provide results showing marked difference in the chemisorptions of dodecane thiol upon Zn- and O

  2. Synthesis, structure and properties of zinc(II) coordination polymers with 9H-carbazole-2,7-dicarboxylic acid

    SciTech Connect

    Yi, Xiu-Chun; Xi, Fu-Gui; Wang, Kun; Su, Zhao; Gao, En-Qing

    2013-10-15

    From a new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid (2,7-H{sub 2}CDC), three Zn(II) metal-organic frameworks were synthesized in the absence or presence of ditopic N-donor ligands. They are formulated as [Zn{sub 5}(μ{sub 3}-OH){sub 2}(2,7-CDC){sub 4}(DEF){sub 2}] (1) (DEF=N,N-diethylformamide), [Zn{sub 2}(2,7-CDC){sub 2}(DABCO)(H{sub 2}O)]·5DMF·H{sub 2}O (2) (DABCO=1-diaza-bicyclo[2.2.2]octane, DMF=N,N-dimethylformamide), and [Zn{sub 2}(2,7-CDC){sub 2}(bpea)]·3DMA·2 H{sub 2}O (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 [Zn{sub 5}(μ{sub 3}-OH){sub 2}(COO){sub 8}] secondary building units (SBUs) are linked by dicarboxylate ligands. Differently, in 3 the well-known paddle–wheel [Zn{sub 2}(COO){sub 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. - Graphical abstract: A new dicarboxylate ligand, 9H-carbazole-2,7-dicarboxylic acid, was used to construct Zn(II) metal-organic frameworks, including a novel self-catenated network with the rare 3D alb-3,6-C2/c net and two pcu-type networks based on an unprecedented pentanuclear clusters and the common paddle–wheel units. The compounds show blue fluorescent properties. Display Omitted - Highlights: • MOFs with a new carbazole-based dicarboxylate ligand. • New pentanuclear [Zn{sub 5}(μ{sub 3}-OH){sub 2}(COO){sub 8}] secondary building unit. • The rare self-catenated 3D alb-3,6-C2/c net.

  3. Effect of added zinc on the properties of cobalt-containing ceramic pigments prepared from layered double hydroxides

    SciTech Connect

    Perez-Bernal, M.E.; Ruano-Casero, R.J.; Rives, V.

    2009-09-15

    Layered double hydroxides (LDHs) with the hydrotalcite-type structure containing Co and Al, or Zn, Co and Al in the brucite-like layers and carbonate in the interlayer have been prepared by coprecipitation. The Zn/Co molar ratio was kept to 1 in all samples, while the divalent/trivalent molar ratio was varied from 2/1 to 1/2. The samples have been characterised by element chemical analysis, powder X-ray diffraction, differential thermal and thermogravimetric analysis, temperature-programmed reduction and FT-IR spectroscopy. A single hydrotalcite-like phase is formed for samples with molar ratio 2/1, which crystallinity decreases as the Al content is increased, developing small amounts of diaspore and dawsonite and probably an additional amorphous phase. Calcination at 1200 deg. C in air led to formation of spinels; a small amount of NaAlO{sub 2} was observed in the Al-rich samples, which was removed by washing. The nature of the spinels formed (containing Co{sup II}, Co{sup III}, Al{sup III} and Zn{sup II}) strongly depends on the cations molar ratio in the starting materials and the calcination treatment, leading to a partial oxidation of Co{sup II} species to Co{sup III} ones. Colour properties (L*a*b*) of the original and calcined solids have been measured. While the original samples show a pink colour (lighter for the series containing Zn), the calcined Co,Al samples show a dark blue colour and the Zn,Co,Al ones a green colour. Changes due to the different molar ratios within a given calcined series are less evident than between samples with the same composition in different series. These calcined materials could be usable as ceramic pigments. - Abstract: Mixed oxides from layered double hydroxides (LDHs) with the hydrotalcite-type structure containing Co and Al or Zn, Co and Al in the brucite-like layers are potential candidates for ceramic pigments with tunable colour properties. Display Omitted

  4. Synthesis and second-order nonlinear optical properties of new copper(II), nickel(II), and zinc(II) Schiff-base complexes. Toward a role of inorganic chromosphores for second harmonic generation

    SciTech Connect

    Lacroix, P.G.; Di Bella, S.; Ledoux, I.

    1996-02-01

    A new Schiff-base ligand based on the condensation of diaminomaleonitrile and 4-(diethylamino)salicylaldehyde is reported with its copper, nickel, and zinc complexes. Their second-order nonlinear optical properties are investigated by electric field induced second harmonic (EFISH) and ZINDO quantum-chemical calculation to probe the role of the metal center in the nonlinearity. All of the complexes exhibit a second-order nonlinear response that is larger than that of the ligand with an hyperpolarizability {beta} value of 400 ({+-}100) 10{sup -30} cm{sup 5} esu{sup -1} for the zinc derivative at 1.34 {mu}m. Theoretical calculations indicate that the two-level model is inadequate to describe the nonlinearity in such systems. 41 refs., 3 figs., 2 tabs.

  5. Structural and magnetic properties of manganese zinc ferrite nanoparticles prepared by solution combustion method using mixture of fuels

    NASA Astrophysics Data System (ADS)

    Angadi, V. Jagadeesha; Rudraswamy, B.; Sadhana, K.; Praveena, K.

    2016-07-01

    The structural analysis and magnetic investigation Mn1-xZnxFe2O4 with stoichiometry (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) were synthesized by solution combustion method using mixture of fuel this is first of its kind. As synthesized Mn-Zn nanoferrites were characterized by X-ray Diffractometer (XRD), Transmission electron microscopy (TEM) at room temperature. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (fr) was increased with the increase in grain size. The Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM). It was observed that the real and imaginary part of permeability (μ‧ and μ″), saturation magnetization (Ms), remanance magnetization (Mr) and magneton number (Mr/Ms) were decreases gradually with increasing Zn2+ concentration. The decrease in the saturation magnetization may be explained as, the Zn2+ concentration increases the relative number of ferric ions on the A sites diminishes and this reduces the A-B interaction. Hence synthesized materials are good for high frequency applications.

  6. Magnetic and microwave absorbing properties of Co2+ substituted nickel-zinc ferrites with the emphasis on initial permeability studies

    NASA Astrophysics Data System (ADS)

    Ghodake, J. S.; Kambale, Rahul C.; Shinde, T. J.; Maskar, P. K.; Suryavanshi, S. S.

    2016-03-01

    Nanocrystalline Co2+ substituted Zn0.35Ni0.60-xCoxFe2.05O4 (Where x=0.0, 0.1, 0.2, 0.3 and 0.4) system have been synthesized by citrate-nitrate combustion route. X-ray diffraction study shows the formation of single phase cubic spinel structure without any impurity phases. Morphological observation shows agglomerated grains with different shapes and sizes which is the typical characteristics of magnetic nanoparticles prepared by combustion route. The saturation magnetization of cobalt substituted Ni-Zn ferrites is found to be higher than that of pure Ni-Zn ferrite. The coercivity and retentivity of cobalt substituted Ni-Zn ferrite increases with the increasing cobalt content. Initial permeability and loss factor have been studied as the function of composition and frequency. The real (μ‧) and imaginary (μ‧‧) part of initial permeability of cobalt substituted Ni-Zn ferrites decreases while its loss factor increases with the increasing cobalt content. In the lower frequency region the imaginary part of initial permeability (μ‧‧) of all samples is found to be decreasing rapidly with increasing frequency. The microwave absorption properties of cobalt substituted Ni-Zn ferrites were also investigated; all samples exhibit the absorption in the frequency range 2.3-2.5 GHz. Thus, the prepared materials can be used as a rubber composite microwave absorber and may be useful in RADAR application.

  7. 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.

  8. Effect of gas flow rate on structural properties of zinc oxide nanowires grown by vapor-solid mechanism

    NASA Astrophysics Data System (ADS)

    Sakrani, S.; Jamaludin, N.; Muhammad, R.; Wahab, Y.; Ismail, A. K.; Suhaimi, S.; Mohammed, Y. H.

    2016-07-01

    ZnO nanowires have been grown on pre-coated (ZnO thin film) silicon (100) substrates with special attention on the effect of gas flow rate. The samples were fabricated using a simple thermal evaporation method within a horizontal quartz tube under controlled supply of Ar and O2 gas where ZnO powder source were previously weighed and heated at 960 °C for 2 h, allowing the reactant vapors to deposit onto substrate to form the nanowires. FESEM images revealed the randomly-oriented nanowires in which the shapes varied with increasing gas flow rates from varied from 90 to 130 sccm. According, both diameter and aspect ratio of the nanowires was observed to shift at 110 sccm where optimum growth condition was expected at this gas flow rate. From EDX spectrum analysis, ZnO nanowires appeared to have uniform composition and purity and confirming the hexagonal wurtzite crystal structure. These measured parameters in combination with unique properties made the possibility of ZnO nanowires potentially useful for functional nanodevices.

  9. Measurements of plasma zinc

    PubMed Central

    Davies, I. J. T.; Musa, M.; Dormandy, T. L.

    1968-01-01

    Zinc is an essential trace element. Previous methods of measuring zinc in clinical material have been difficult and reported findings must be treated with caution. Using atomic absorption spectroscopy it has been established that plasma zinc is one of the most uniform biochemical characteristics of normal adult blood. Sex and age differences in adult life are insignificant. Increased metabolic activity, on the other hand, induces a marked, immediate fall in plasma zinc level. The possible implications of this are discussed. Zinc levels in patients with diabetes mellitus, cardiovascular disease, and anaemia due to acute blood loss have been within normal limits. Plasma zinc is low in certain types of liver disease. PMID:5303355

  10. Is zinc a neuromodulator?

    PubMed

    Kay, Alan R; Tóth, Katalin

    2008-01-01

    The vesicles of certain glutamatergic terminals in the mammalian forebrain are replete with ionic zinc. It is believed that during synaptic transmission zinc is released, binds to receptors on the pre- or postsynaptic membranes, and hence acts as a neuromodulator. Although exogenous zinc modulates a wide variety of channels, whether synaptic zinc transits across the synaptic cleft and alters the response of channels has been difficult to establish. We will review the evidence for zinc as a neuromodulator and propose diagnostic criteria for establishing whether it is indeed one. Moreover, we will delineate alternative ways in which zinc might act at synapses.

  11. A two-dimensional zinc(II) coordination polymer based on mixed dimethyl succinate and bipyridine ligands: synthesis, structure, thermostability and luminescence properties.

    PubMed

    Liu, Yang; Feng, Yong Lan; Fu, Wei Wei

    2016-04-01

    From the viewpoint of crystal engineering, the construction of crystalline polymeric materials requires a rational choice of organic bridging ligands for the self-assembly process. Multicarboxylate ligands are of particular interest due to their strong coordination activity towards metal ions, as well as their various coordination modes and versatile conformations. The structural chemistry of dicarboxylate-based coordination polymers of transition metals has been developed through the grafting of N-containing organic linkers into carboxylate-bridged transition metal networks. A new luminescent two-dimensional zinc(II) coordination polymer containing bridging 2,2-dimethylsuccinate and 4,4'-bipyridine ligands, namely poly[[aqua(μ2-4,4'-bipyridine-κ(2)N:N')bis(μ3-2,2-dimethylbutanedioato)-κ(4)O(1),O(1'):O(4):O(4');κ(5)O(1):O(1),O(4):O(4),O(4')-dizinc(II)] dihydrate], {[Zn2(C6H8O4)2(C10H8N2)(H2O)]·2H2O}n, has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and elemental, IR and thermogravimetric analyses. In the structure, the 2,2-dimethylsuccinate ligands link linear tetranuclear Zn(II) subunits into one-dimensional chains along the c axis. 4,4'-Bipyridine acts as a tethering ligand expanding these one-dimensional chains into a two-dimensional layered structure. Hydrogen-bonding interactions between the water molecules (both coordinated and free) and carboxylate O atoms strengthen the packing of the layers. Furthermore, the luminescence properties of the complex were investigated. The compound exhibits a blue photoluminescence in the solid state at room temperature and may be a good candidate for potential hybrid inorganic-organic photoactive materials.

  12. 12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF DEPLETED URANIUM INGOT AND MOLDS. DEPLETED URANIUM CASTING OPERATIONS CEASED IN 1988. (11/14/57) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

  13. Comparison of the Mechanism of Toxicity of Zinc Oxide and Cerium Oxide Nanoparticles Based on Dissolution and Oxidative Stress Properties

    PubMed Central

    Xia, Tian; Kovochich, Michael; Liong, Monty; Mädler, Lutz; Gilbert, Benjamin; Shi, Haibin; Yeh, Joanne I.; Zink, Jeffrey I.; Nel, Andre E.

    2014-01-01

    Nanomaterials (NM) exhibit novel physicochemical properties that determine their interaction with biological substrates and processes. Three metal oxides nanoparticles that are currently being produced in high tonnage, TiO2, ZnO and CeO2, were synthesized by flame spray pyrolysis process and compared in a mechanistic study to elucidate the physicochemical characteristics that determine cellular uptake, subcellular localization, and toxic effects based on a test paradigm that was originally developed for oxidative stress and cytotoxicity in RAW 264.7 and BEAS-2B cell lines. ZnO induced toxicity in both cells, leading to the generation of reactive oxygen species (ROS), oxidant injury, excitation of inflammation and cell death. Using ICP-MS and fluorescent-labeled ZnO, it is found that ZnO dissolution could happen in culture medium and endosomes. Non-dissolved ZnO nanoparticles enter caveolae in BEAS-2B, but enter lysosomes in RAW 264.7 cells in which smaller particle remnants dissolve. In contrast, fluorescent-labeled CeO2 nanoparticles were taken up intact into caveolin-1 and LAMP-1 positive endosomal compartments, respectively, in BEAS-2B and RAW 264.7 cells, without inflammation or cytotoxicity. Instead, CeO2 suppressed ROS production and induced cellular resistance to an exogenous source of oxidative stress. Fluorescent-labeled TiO2 was processed by the same uptake pathways as CeO2 but did not elicit any adverse or protective effects. These results demonstrate that metal oxide nanoparticles induce a range of biological responses that vary from cytotoxic to cytoprotective and can only be properly understood by using a tiered test strategy such as we developed for oxidative stress and adapted to study other aspects of nanoparticle toxicity. PMID:19206459

  14. Depleted Uranium in Repositories

    SciTech Connect

    Haire, M.J.; Croff, A.G.

    1997-12-31

    For uranium to be useful in most fission nuclear reactors, it must be enriched (i.e. the concentration of the fissile isotope 235U must be increased). Therefore, depleted uranium (DU)-uranium which has less than naturally occurring concentrations of 235U-is a co-product of the enrichment process. Four to six tons of DU exist for every ton of fresh light water reactor fuel. There were 407,006 MgU 407,000 metric tons (t) of DU stored on U.S. Department of Energy (DOE) sites as of July 1993. If this DU were to be declared surplus, converted to a stable oxide form, and emplaced in a near surface disposal facility, the costs are estimated to be several billion dollars. However, the U.S. Nuclear Regulatory Commission has stated that near surface disposal of large quantities of DU tails is not appropriate. Thus, there is the possibility that disposition via disposal will be in a deep geological repository. One alternative that may significantly reduce the cost of DU disposition is to use it beneficially. In fact, DOE has begun the Beneficial Uses of DU Project to identify large scale uses of DU and to encourage its reuse. Several beneficial uses, many of which involve applications in the repository per se or in managing the wastes to go into the repository, are discussed in this report.

  15. Crosstalk between Zinc Status and Giardia Infection: A New Approach.

    PubMed

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

    2015-06-03

    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.

  16. 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

  17. Zinc oxide overdose

    MedlinePlus

    Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

  18. Bacitracin zinc overdose

    MedlinePlus

    ... Small amounts of bacitracin zinc are dissolved in petroleum jelly to create antibiotic ointments. Bacitracin zinc overdose ... is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation ...

  19. Ego depletion impairs implicit learning.

    PubMed

    Thompson, Kelsey R; Sanchez, Daniel J; Wesley, Abigail H; Reber, Paul J

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent.

  20. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.

  1. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  2. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  3. Zinc and gastrointestinal disease

    PubMed Central

    Skrovanek, Sonja; DiGuilio, Katherine; Bailey, Robert; Huntington, William; Urbas, Ryan; Mayilvaganan, Barani; Mercogliano, Giancarlo; Mullin, James M

    2014-01-01

    This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases. PMID:25400994

  4. Controlling the electrical properties of ZnO films by forming zinc and oxide bridges by a plasma and electron-assisted process

    SciTech Connect

    Shimoi, Norihiro; Tanaka, Yasumitsu; Harada, Takamitsu; Tanaka, Shun-ichiro

    2012-06-15

    A new method to produce electrically steady ZnO films without any heating process has been developed by using plasma and electron beams to facilitate bonding between the metallic component and the oxygen on coated ZnO films. Both plasma atmosphere and electron beams can function as sources of nonequilibrium bonding energy, forming bridges between the zinc present in the zinc complex and the oxygen in the ZnO particles to construct a zinc-oxide thin film. Our results confirm that it is possible to achieve low conductive characteristics by controlling the acceleration voltage of electrons used to irradiate the ZnO coating. The electrically steady films fabricated have various potential applications, being particularly well-suited to electrical devices on a plastic medium.

  5. Characterization of Monolayer Formation on Aluminum-Doped Zinc Oxide Thin Films

    SciTech Connect

    Rhodes,C.; Lappi, S.; Fischer, D.; Sambasivan, S.; Genzer, J.; Franzen, S.

    2008-01-01

    The optical and electronic properties of aluminum-doped zinc oxide (AZO) thin films on a glass substrate are investigated experimentally and theoretically. Optical studies with coupling in the Kretschmann configuration reveal an angle-dependent plasma frequency in the mid-IR for p-polarized radiation, suggestive of the detection of a Drude plasma frequency. These studies are complemented by oxygen depletion density functional theory studies for the calculation of the charge carrier concentration and plasma frequency for bulk AZO. In addition, we report on the optical and physical properties of thin film adlayers of n-hexadecanethiol (HDT) and n-octadecanethiol (ODT) self-assembled monolayers (SAMs) on AZO surfaces using reflectance FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Our characterization of the SAM deposition onto the AZO thin film reveals a range of possible applications for this conducting metal oxide.

  6. 26 CFR 1.611-1 - Allowance of deduction for depletion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Natural Resources § 1.611-1 Allowance of deduction for depletion. (a) Depletion of mines, oil and gas wells, other natural deposits, and timber—(1) In general... of the property. In the case of other exhaustible natural resources the allowance for depletion...

  7. 26 CFR 1.611-1 - Allowance of deduction for depletion.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Natural Resources § 1.611-1 Allowance of deduction for depletion. (a) Depletion of mines, oil and gas wells, other natural deposits, and timber—(1) In general... of the property. In the case of other exhaustible natural resources the allowance for depletion...

  8. Testing fully depleted CCD

    NASA Astrophysics Data System (ADS)

    Casas, Ricard; Cardiel-Sas, Laia; Castander, Francisco J.; Jiménez, Jorge; de Vicente, Juan

    2014-08-01

    The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892-04(X). These detectors are 200 μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm. The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD read-out speed is 133 kpixel/s. This is the value used in the calibration process. Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC- IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain). The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency (CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum efficiency. The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB). Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to electrical fields. Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a defectous coating process.

  9. Implication of zinc excess on soil health.

    PubMed

    Wyszkowska, Jadwiga; Boros-Lajszner, Edyta; Borowik, Agata; Baćmaga, Małgorzata; Kucharski, Jan; Tomkiel, Monika

    2016-01-01

    This study was undertaken to evaluate zinc's influence on the resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease. The experiment was conducted in a greenhouse of the University of Warmia and Mazury (UWM) in Olsztyn, Poland. Plastic pots were filled with 3 kg of sandy loam with pHKCl - 7.0 each. The experimental variables were: zinc applied to soil at six doses: 100, 300, 600, 1,200, 2,400 and 4,800 mg of Zn(2+) kg(-1) in the form of ZnCl2 (zinc chloride), and species of plant: oat (Avena sativa L.) cv. Chwat and white mustard (Sinapis alba) cv. Rota. Soil without the addition of zinc served as the control. During the growing season, soil samples were subjected to microbiological analyses on experimental days 25 and 50 to determine the abundance of organotrophic bacteria, actinomyces and fungi, and the activity of dehydrogenases, catalase and urease, which provided a basis for determining the soil resistance index (RS). The physicochemical properties of soil were determined after harvest. The results of this study indicate that excessive concentrations of zinc have an adverse impact on microbial growth and the activity of soil enzymes. The resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease decreased with an increase in the degree of soil contamination with zinc. Dehydrogenases were most sensitive and urease was least sensitive to soil contamination with zinc. Zinc also exerted an adverse influence on the physicochemical properties of soil and plant development. The growth of oat and white mustard plants was almost completely inhibited in response to the highest zinc doses of 2,400 and 4,800 mg Zn(2+) kg(-1).

  10. Implication of zinc excess on soil health.

    PubMed

    Wyszkowska, Jadwiga; Boros-Lajszner, Edyta; Borowik, Agata; Baćmaga, Małgorzata; Kucharski, Jan; Tomkiel, Monika

    2016-01-01

    This study was undertaken to evaluate zinc's influence on the resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease. The experiment was conducted in a greenhouse of the University of Warmia and Mazury (UWM) in Olsztyn, Poland. Plastic pots were filled with 3 kg of sandy loam with pHKCl - 7.0 each. The experimental variables were: zinc applied to soil at six doses: 100, 300, 600, 1,200, 2,400 and 4,800 mg of Zn(2+) kg(-1) in the form of ZnCl2 (zinc chloride), and species of plant: oat (Avena sativa L.) cv. Chwat and white mustard (Sinapis alba) cv. Rota. Soil without the addition of zinc served as the control. During the growing season, soil samples were subjected to microbiological analyses on experimental days 25 and 50 to determine the abundance of organotrophic bacteria, actinomyces and fungi, and the activity of dehydrogenases, catalase and urease, which provided a basis for determining the soil resistance index (RS). The physicochemical properties of soil were determined after harvest. The results of this study indicate that excessive concentrations of zinc have an adverse impact on microbial growth and the activity of soil enzymes. The resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease decreased with an increase in the degree of soil contamination with zinc. Dehydrogenases were most sensitive and urease was least sensitive to soil contamination with zinc. Zinc also exerted an adverse influence on the physicochemical properties of soil and plant development. The growth of oat and white mustard plants was almost completely inhibited in response to the highest zinc doses of 2,400 and 4,800 mg Zn(2+) kg(-1). PMID:26828860

  11. Metallothionein and Zinc Transporter Expression in Circulating Human Blood Cells as Biomarkers of Zinc Status: a Systematic Review.

    PubMed

    Hennigar, Stephen R; Kelley, Alyssa M; McClung, James P

    2016-07-01

    Zinc is an essential nutrient for humans; however, a sensitive biomarker to assess zinc status has not been identified. The objective of this systematic review was to compile and assess studies that determined zinc transporter and/or metallothionein expression in various blood cell types and to determine their reliability and sensitivity to changes in dietary zinc. Sixteen studies were identified that determined the expression of zrt-, irt-like protein (ZIP) 1 [solute carrier family (SLC) 39A1], ZIP3 (SLC39A3), ZIP5 (SLC39A5), ZIP6 (SLC39A6), ZIP7 (SLC39A7), ZIP8 (SLC39A8), ZIP10 (SLC39A10), ZIP14 (SLC39A14), zinc transporter (ZnT)1 (SLC30A1), ZnT2 (SLC30A2), ZnT4 (SLC30A4), ZnT5 (SLC30A5), ZnT6 (SLC30A6), ZnT7 (SLC30A7), ZnT9 (SLC30A9), and/or metallothionein in various blood cells isolated from healthy adult men and women in response to zinc supplementation or depletion. Cell types included leukocytes, peripheral blood mononuclear cells, T lymphocytes, monocytes, and erythrocytes. ZIP1, ZnT1, and metallothionein were the most commonly measured proteins. Changes in ZIP1 and ZnT1 in response to zinc supplementation or depletion were not consistent across studies. Leukocyte metallothionein decreased with zinc depletion (-39% change from baseline, <5 mg Zn/d, n = 2 studies) and increased with zinc supplementation in a dose-dependent manner (35%, 15-22 mg Zn/d, n = 7 studies; 267%, 50 mg Zn/d, n = 2 studies) and at the earliest time points measured; however, no change or delayed response was observed in metallothionein in erythrocytes. A greater percentage of studies demonstrated that metallothionein in leukocyte subtypes was a more reliable (100%, n = 12; 69%, n = 16) and responsive (92%, n = 12; 82%, n = 11) indicator of zinc exposure than was plasma zinc, respectively. In conclusion, current evidence indicates that metallothionein in leukocyte subtypes may be a component in determining zinc status. PMID:27422508

  12. Zinc oxyfluoride transparent conductor

    SciTech Connect

    Gordon, R.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 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. 8 figures.

  13. 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.

  14. Topological evolution and photoluminescent properties of a series of divalent zinc-based metal–organic frameworks tuned via ancillary ligating spacers

    SciTech Connect

    Lian, Xiao-Min; Zhao, Wen; Zhao, Xiao-Li

    2013-04-15

    The combination of divalent zinc ions, 4-(4-carboxybenzamido)benzoic acid and exo-bidendate bipyridine ligands gave rise to a series of new MOFs: [ZnL(bipy)]·DMF·H{sub 2}O (1), [ZnL(bpe)]·1.5H{sub 2}O (2), [ZnL(bpa)]·4H{sub 2}O (3) and [ZnL(bpp)]·1.75H{sub 2}O (4) (MOF=metal-organic framework, bipy=4,4′-bipyridine, bpe=trans-1,2-bis(4-pyridyl)ethylene, bpa=1,2-bis(4-pyridinyl)ethane, bpp=1,3-bis(4-pyridinyl)propane, H{sub 2}L=4,4′-(carbonylimino)dibenzoic acid). Fine tune over the topology of the MOFs was achieved via systematically varying the geometric length of the second ligating bipyridine ligands. Single-crystal X-ray analysis reveals that complex 1 has a triply interpenetrated three-dimensional (3D) framework with elongated primitive cubic topology, whereas isostructural complexes 2 and 3 each possesses a 6-fold interpenetrated diamondiod 3D framework. Further expansion of the length of the bipyridine ligand to bpp leads to the formation of 4, which features an interesting entangled architecture of 2D→3D parallel polycatenation. In addition, the thermogravimetric analyses and solid-state photoluminescent properties of the selected complexes are investigated. - Graphical abstract: The incorporation of exo-bidendate bipyridine spacers into the Zn–H{sub 2}L system has yielded a series of new MOFs exhibiting topological evolution from 3-fold interpenetration to 6-fold interpenetration and 2D→3D parallel polycatenation. Highlights: ► The effect of the pyridyl-based spacers on the formation of MOFs was explored. ► Fine tune over the topology of the MOFs was achieved. ► An interesting structure of 2D→3D parallel polycatenation is reported.

  15. Synthesis, crystal structure, and spectroscopic and thermal properties of the polymeric compound catena-poly[[bis(2,4-dichlorobenzoato)zinc(II)]-μ-isonicotinamide].

    PubMed

    Homzová, Katarína; Györyová, Katarína; Koman, Marián; Melník, Milan; Juhászová, Žofia

    2015-09-01

    Zinc(II) carboxylates with O-, S- and N-donor ligands are interesting for their structural features, as well as for their antibacterial and antifungal activities. The one-dimensional zinc(II) coordination complex catena-poly[[bis(2,4-dichlorobenzoato-κO)zinc(II)]-μ-isonicotinamide-κ(2)N(1):O], [Zn(C7H3Cl2O2)2(C6H6N2O)]n, has been prepared and characterized by IR spectroscopy, single-crystal X-ray analysis and thermal analysis. The tetrahedral ZnO3N coordination about the Zn(II) cation is built up by the N atom of the pyridine ring, an O atom of the carbonyl group of the isonicotinamide ligand and two O atoms of two dichlorobenzoate ligands. Isonicotinamide serves as a bridge between tetrahedra, with a Zn···Zn distance of 8.8161 (7) Å. Additionally, π-π interactions between the planar benzene rings contribute to the stabilization of the extended structure. The structure is also stabilized by intermolecular hydrogen bonds between the amino and carboxylate groups of the ligands, forming a two-dimensional network. During thermal decomposition of the complex, isonicotinamide, dichlorobenzene and carbon dioxide were evolved. The final solid product of the thermal decomposition heated up to 1173 K was metallic zinc. PMID:26322615

  16. Synthesis, crystal structure, and spectroscopic and thermal properties of the polymeric compound catena-poly[[bis(2,4-dichlorobenzoato)zinc(II)]-μ-isonicotinamide].

    PubMed

    Homzová, Katarína; Györyová, Katarína; Koman, Marián; Melník, Milan; Juhászová, Žofia

    2015-09-01

    Zinc(II) carboxylates with O-, S- and N-donor ligands are interesting for their structural features, as well as for their antibacterial and antifungal activities. The one-dimensional zinc(II) coordination complex catena-poly[[bis(2,4-dichlorobenzoato-κO)zinc(II)]-μ-isonicotinamide-κ(2)N(1):O], [Zn(C7H3Cl2O2)2(C6H6N2O)]n, has been prepared and characterized by IR spectroscopy, single-crystal X-ray analysis and thermal analysis. The tetrahedral ZnO3N coordination about the Zn(II) cation is built up by the N atom of the pyridine ring, an O atom of the carbonyl group of the isonicotinamide ligand and two O atoms of two dichlorobenzoate ligands. Isonicotinamide serves as a bridge between tetrahedra, with a Zn···Zn distance of 8.8161 (7) Å. Additionally, π-π interactions between the planar benzene rings contribute to the stabilization of the extended structure. The structure is also stabilized by intermolecular hydrogen bonds between the amino and carboxylate groups of the ligands, forming a two-dimensional network. During thermal decomposition of the complex, isonicotinamide, dichlorobenzene and carbon dioxide were evolved. The final solid product of the thermal decomposition heated up to 1173 K was metallic zinc.

  17. [Zinc and gastrointestinal disorders].

    PubMed

    Higashimura, Yasuki; Takagi, Tomohisa; Naito, Yuji

    2016-07-01

    Zinc, an essential trace element, affects immune responses, skin metabolism, hormone composition, and some sensory function, so that the deficiency presents various symptoms such as immunodeficiency and taste obstacle. Further, the zinc deficiency also considers as a risk of various diseases. Recent reports demonstrated that -20% of the Japanese population was marginally zinc deficiency, and over 25% of the global population is at high risk of zinc deficiency. In gastrointestinal disorders, zinc plays an important role in the healing of mucosal and epithelial damage. In fact, polaprezinc, a chelate compound of zinc and L-carnosine, has been used for the treatment of gastric ulcer and gastritis. We describe here the therapeutic effect of zinc on gastrointestinal disorders. PMID:27455800

  18. Effect of zinc-borate glass addition on the thermal properties of the cordierite/Al2O3 composites containing nano-sized spinel crystal.

    PubMed

    Jo, Sinae; Kang, Seunggu

    2013-11-01

    Low-melting zinc-borate glass was added to the cordierite/Al2O3 composite in order to improve the sintering facility of Al2O3 and formation of nano-sized spinel crystal of high thermal conductivity. Increasing the ZnO/B2O3 ratio in the zinc-borate glass increased the ZnAl2O4 spinel and decreased the Al4B2O9 crystal peak intensities in X-ray diffraction pattern. The XRD peak intensities of the ZnAl2O4 spinel and Al4B2O9 crystals in the specimen containing 10 wt% zinc-borate glass (10G series) are higher than that of the specimen containing 5 wt% zinc-borate glass (5G series). The microstructures of most 10G series specimens had the flower-shaped crystal which was composed of 50 nm wide and 250 nm long needle-like crystals and identified as ZnAl2O4 spinel phase. The thermal conductivity of the 10G series specimen was higher than that of the 5G series in any ZnO/B2O3 ratio due to the formation of plenty of nano-sized ZnAl2O4 spinel of high thermal conductivity. Particularly, the thermal conductivity of the cordierite/Al2O3 composite containing 10 wt% zinc-borate glass of ZnO/B2O3 weight ratio = 1.5 was 3.8 W/Km which is much higher than that of the published value (3.0 W/Km).

  19. ZINC MITIGATION INTERIM REPORT - THERMODYNAMIC STUDY

    SciTech Connect

    Korinko, P.

    2010-12-17

    An experimental program was initiated in order to develop and validate conditions that will effectively trap Zn vapors that are released during extraction. The proposed work is broken down into three tasks. The first task is to determine the effectiveness of various pore sizes of filter elements. The second task is to determine the effect of filter temperature on zinc vapor deposition. The final task is to determine whether the zinc vapors can be chemically bound. The approach for chemically binding the zinc vapors has two subtasks, the first is a review of literature and thermodynamic calculations and the second is an experimental approach using the best candidates. This report details the results of the thermodynamic calculations to determine feasibility of chemically binding the zinc vapors within the furnace module, specifically the lithium trap (1). A review of phase diagrams, literature, and thermodynamic calculations was conducted to determine if there are suitable materials to capture zinc vapor within the lithium trap of the extraction basket. While numerous elements exist that form compounds with zinc, many of these also form compounds with hydrogen or the water that is present in the TPBARs. This relatively comprehensive review of available data indicates that elemental cobalt and copper and molybdenum trioxide (MoO3) may have the requisite properties to capture zinc and yet not be adversely affected by the extraction gases and should be considered for testing.

  20. Solution Grown Antimony Doped Zinc Oxide Films

    NASA Astrophysics Data System (ADS)

    Riley, Conor T.

    Zinc oxide is an extensively studied semiconducting material due to its versatile properties applicable to many technologies such as electronics, optoelectronics, sensing and renewable energy. Although zinc oxide films have been created for device fabrication, the methods used to synthesize them are expensive and unrealistic for affordable commercial devices. In addition, zinc oxide is intrinsically n-type making the realization of stable p-type materials a great challenge for light emitting diodes, solar cells and UV lasing. In this thesis zinc oxide films are created using low cost solution methods. To accomplish this, a previously unreported surfactant, tert-butanol, is used. Several controlled experiments vary the concentration of tert-butanol, zinc and oxygen sources to demonstrate the ability of tert-butanol to create low cost films. Further, small amounts of antimony glycolate are added to the reaction solution, to create antimony doped zinc oxide films on sapphire and silicon substrates. Although hall measurements indicate that the films are n-type, a discussion of antimony activation provides a feasible path for the realization of low cost, p-type zinc oxide films.

  1. The Essential Toxin: Impact of Zinc on Human Health

    PubMed Central

    Plum, Laura M.; Rink, Lothar; Haase, Hajo

    2010-01-01

    Compared to several other metal ions with similar chemical properties, zinc is relatively harmless. Only exposure to high doses has toxic effects, making acute zinc intoxication a rare event. In addition to acute intoxication, long-term, high-dose zinc supplementation interferes with the uptake of copper. Hence, many of its toxic effects are in fact due to copper deficiency. While systemic homeostasis and efficient regulatory mechanisms on the cellular level generally prevent the uptake of cytotoxic doses of exogenous zinc, endogenous zinc plays a significant role in cytotoxic events in single cells. Here, zinc influences apoptosis by acting on several molecular regulators of programmed cell death, including caspases and proteins from the Bcl and Bax families. One organ where zinc is prominently involved in cell death is the brain, and cytotoxicity in consequence of ischemia or trauma involves the accumulation of free zinc. Rather than being a toxic metal ion, zinc is an essential trace element. Whereas intoxication by excessive exposure is rare, zinc deficiency is widespread and has a detrimental impact on growth, neuronal development, and immunity, and in severe cases its consequences are lethal. Zinc deficiency caused by malnutrition and foods with low bioavailability, aging, certain diseases, or deregulated homeostasis is a far more common risk to human health than intoxication. PMID:20617034

  2. Zinc toxicosis due to ingestion of a penny in a gray-headed chachalaca (Ortalis cinereiceps).

    PubMed

    Droual, R; Meteyer, C U; Galey, F D

    1991-01-01

    Zinc toxicosis was diagnosed in a gray-headed chachalaca (Ortalis cinereiceps) due to ingestion of a copper-plated zinc penny. Histopathological lesions were most marked in the pancreas. These lesions included apoptosis, zymogen granule depletion, and loss of normal acinar architecture. There was also severe gizzard erosion. Heavy metal analysis revealed abnormal levels of zinc and iron in the liver. Iron pigment in the liver was most concentrated in Kupffer cells. This, along with evidence of erythrophagocytosis in the spleen, suggested that extravascular hemolysis was also associated with zinc toxicosis in this case.

  3. Origin of Enthalpic Depletion Forces.

    PubMed

    Sapir, Liel; Harries, Daniel

    2014-04-01

    Solutes excluded from macromolecules or colloids are known to drive depletion attractions. The established Asakura-Oosawa model, as well as subsequent theories aimed at explaining the effects of macromolecular crowding, attribute depletion forces to diminished hard-core excluded volume upon compaction, and hence predict depletion forces dominated by entropy. However, recent experiments measuring the effect of preferentially excluded solutes on protein folding and macromolecular association find these forces can also be enthalpic. We use simulations of macromolecular association in explicit binary cosolute-solvent mixtures, with solvent and cosolute intermolecular interactions that go beyond hard-cores, to show that not all cosolutes conform to the established entropically dominated model. We further demonstrate how the enthalpically dominated depletion forces that we find can be well described within an Asakura-Oosawa like model provided that the hard-core macromolecule-cosolute potential of mean force is augmented by a "soft" step-like repulsion.

  4. Zinc abundances of planetary nebulae

    NASA Astrophysics Data System (ADS)

    Smith, C. L.; Zijlstra, A. A.; Dinerstein, H. L.

    2014-07-01

    Zinc is a useful surrogate element for measuring Fe/H as, unlike iron, it is not depleted in the gas phase media. Zn/H and O/Zn ratios have been derived using the [Zn IV] emission line at 3.625 μm for a sample of nine Galactic planetary nebulae, seven of which are based upon new observations using the Very Large Telescope (VLT). Based on photoionization models, O/O++ is the most reliable ionization correction factor for zinc that can readily be determined from optical emission lines, with an estimated accuracy of 10 per cent or better for all targets in our sample. The majority of the sample is found to be subsolar in [Zn/H]. [O/Zn] in half of the sample is found to be consistent with solar within uncertainties, whereas the remaining half are enhanced in [O/Zn]. [Zn/H] and [O/Zn] as functions of Galactocentric distance have been investigated and there is little evidence to support a trend in either case.

  5. Ego depletion impairs implicit learning.

    PubMed

    Thompson, Kelsey R; Sanchez, Daniel J; Wesley, Abigail H; Reber, Paul J

    2014-01-01

    Implicit skill learning occurs incidentally and without conscious awareness of what is learned. However, the rate and effectiveness of learning may still be affected by decreased availability of central processing resources. Dual-task experiments have generally found impairments in implicit learning, however, these studies have also shown that certain characteristics of the secondary task (e.g., timing) can complicate the interpretation of these results. To avoid this problem, the current experiments used a novel method to impose resource constraints prior to engaging in skill learning. Ego depletion theory states that humans possess a limited store of cognitive resources that, when depleted, results in deficits in self-regulation and cognitive control. In a first experiment, we used a standard ego depletion manipulation prior to performance of the Serial Interception Sequence Learning (SISL) task. Depleted participants exhibited poorer test performance than did non-depleted controls, indicating that reducing available executive resources may adversely affect implicit sequence learning, expression of sequence knowledge, or both. In a second experiment, depletion was administered either prior to or after training. Participants who reported higher levels of depletion before or after training again showed less sequence-specific knowledge on the post-training assessment. However, the results did not allow for clear separation of ego depletion effects on learning versus subsequent sequence-specific performance. These results indicate that performance on an implicitly learned sequence can be impaired by a reduction in executive resources, in spite of learning taking place outside of awareness and without conscious intent. PMID:25275517

  6. Atmospheric Corrosion and Precipitation Runoff From Zinc and Zinc Alloys Surfaces

    SciTech Connect

    Matthes, S.A.; Cramer, S.D.; Bullard, S.J.; Covino, B.S., Jr.; Holcomb, G.R.

    2003-03-16

    The long-term atmospheric corrosion performance of rolled zinc and three thermal-sprayed (TS) zinc materials (Zn, Zn-15Al, and Al-12Zn-0.2In) was characterized by measuring corrosion product concentrations in precipitation runoff at coastal marine and inland sites. Corrosion rates and average zinc concentrations in the runoff were greater at the site having higher annual rainfall. Higher chloride concentrations did not seem to affect either the corrosion rates or the zinc concentrations in the runoff at the coastal site compared to those of the inland site. Zinc runoff concentrations were higher for TS Zn than rolled zinc due to the greater surface area of the thermal-sprayed surface. Average cumulative zinc runoff losses for the two sites were: 64 {micro}mol Zn/L for TS Zn, 37 {micro}mol Zn/L for rolled Zn, 24 {micro}mol Zn/L for TS Zn-15Al, and 1.8 {micro}mol Zn/L for TS Al-12Zn-0.2In. Cumulative zinc runoff losses were directly related both to the precipitation rate and to the availability of Zn in metal surfaces, a consequence of surface roughness and surface chemistry properties of the metal.

  7. Cysteine-rich intestinal protein binds zinc during transmucosal zinc transport.

    PubMed Central

    Hempe, J M; Cousins, R J

    1991-01-01

    The mechanism of zinc absorption has not been delineated, but kinetic studies show that both passive and carrier-mediated processes are involved. We have identified a low molecular mass zinc-binding protein in the soluble fraction of rat intestinal mucosa that could function as an intracellular zinc carrier. The protein was not detected in liver or pancreas, suggesting a role specific to the intestine. The protein binds zinc during transmucosal zinc transport and shows signs of saturation at higher luminal zinc concentrations, characteristics consistent with a role in carrier-mediated zinc absorption. Microsequence analysis of the protein purified by gel-filtration HPLC and SDS/PAGE showed complete identity within the first 41 N-terminal amino acids with the deduced protein sequence of cysteine-rich intestinal protein [Birkenmeier, E. H. & Gordon, J. I. (1986) Proc. Natl. Acad. Sci. USA 83, 2516-2520]. These investigators showed that the gene for this protein is developmentally regulated in neonates during the suckling period, conserved in many vertebrate species, and predominantly expressed in the small intestine. Cysteine-rich intestinal protein contains a recently identified conserved sequence of histidine and cysteine residues, the LIM motif, which our results suggest confers metal-binding properties that are important for zinc transport and/or functions of this micronutrient. Images PMID:1946385

  8. [Significance of zinc and sarcopenia in patients undergoing surgery].

    PubMed

    Kaido, Toshimi; Tamai, Yumiko; Uemoto, Shinji

    2016-07-01

    Sarcopenia is characterized by muscle mass depletion and decrease in muscle power or physical activity. We evaluated significance of sarcopenia in patients undergoing living donor liver transplantation (LDLT). Patients with low skeletal muscle mass (SMM) had significantly worse survival compared with patients with normal/high SMM (p < 0.001). Correlations of preoperative zinc with prealbumin and branched-chain amino acids were significantly positive. While, correlations of zinc with tyrosine and ammonia levels were significantly negative. The low pre-transplant zinc level steeply dropped for 2/3 days after LDLT and subsequently increased back to reach the pre-transplant level around the postoperative day 5, and continued to increase until normalized during 2 weeks. Perioperative nutritional therapy including zinc supplement significantly increased survival in patients with low SMM (p = 0.009). PMID:27455815

  9. Syntheses and properties of zinc and calcium complexes of valinate and isovalinate: metal alpha-amino acidates as possible constituents of the early Earth's chemical inventory.

    PubMed

    Strasdeit, H; Büsching, I; Behrends, S; Saak, W; Barklage, W

    2001-03-01

    We have studied the ligand behavior of racemic isovalinate (iva) and valinate (val) towards zinc(II) and calcium(II). The following solid metal amino acidates were obtained from aqueous solutions: Zn3Cl2(iva)4 (1), Zn3Cl2(val)4 (2). Zn(val)2 (3), Zn(iva)2 x 2H2O (4), Zn(iva)2 x 3.25H2O (5), Zn(iva)2 (6), Ca(iva)2x xH2O (7), and Ca(val)2 x H2O (8). Except for complex 3, these were hitherto unknown compounds. The conditions under which they formed, together with current ideas of the conditions on early Earth, support the assumption that alpha-amino acidate complexes of zinc and calcium might have belonged to early Earth's prebiotic chemical inventory. The zinc isovalinates 1, 4, and 5 were characterized by X-ray crystal structure analyses. Complex 1 forms a layer structure containing four- and five-coordinate metal atoms, whereas the zinc atoms in 4 and 5 are five-coordinate. Compound 5 possesses an unprecedented nonpolymeric structure built from cyclic [Zn6(iva)12] complexes, which are separated by water molecules. The thermolyses of solids 1. 3, and 8 at 320 degrees C in an N2 atmosphere yielded numerous organic products, including the cyclic dipeptide of valine from 3 and 8. Condensation, C-C bond breaking and bond formation, aromatization, decarboxylation, and deamination reactions occurred during the thermolyses. Such reactions of metal-bound a-amino acidates that are abiotically formed could already have contributed to an organic-geochemical diversity before life appeared on Earth.

  10. Improved zinc electrode and rechargeable zinc-air battery

    DOEpatents

    Ross, P.N. Jr.

    1988-06-21

    The invention comprises an improved rechargeable zinc-air cell/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

  11. [Zinc and autophagy].

    PubMed

    Qiaoyun, Liu; Hanming, Shen; Dajing, Xia

    2016-05-25

    Autophagy refers to a catabolic process,in which the damaged organelles or biological macromolecules, such as protein aggregates, are degraded via lysosome. The completion of autophagy depends on a series of autophagy-related genes (Atgs) and many upstream regulatory molecules. Zinc is an essential trace element, and plays an important role in the process of autophagy as a component of enzymes and structural proteins like zinc transporters or zinc finger protein. The regulation of autophagy is closely associated with the zinc ion homeostasis. In addition, many studies suggest that the protective effects of zinc on cells are likely to be done by autophagy. This review aims to summarize the current research progress and discuss the reciprocal regulation mechanism between zinc and autophagy, which may provide insights into the intricate roles of autophagy in diseases and find novel strategies for treatment and prevention of human diseases. PMID:27651198

  12. Zinc electrode and rechargeable zinc-air battery

    SciTech Connect

    Ross, P.N. Jr.

    1989-06-27

    This patent describes an improved zinc electrode for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed.

  13. 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.

  14. Control of zinc homeostasis in Agrobacterium tumefaciens via zur and the zinc uptake genes znuABC and zinT.

    PubMed

    Bhubhanil, Sakkarin; Sittipo, Panida; Chaoprasid, Paweena; Nookabkaew, Sumontha; Sukchawalit, Rojana; Mongkolsuk, Skorn

    2014-11-01

    The Agrobacterium tumefaciens zinc uptake regulator (Zur) was shown to negatively regulate the zinc uptake genes znuABC, encoding a zinc transport system belonging to the ATP-binding cassette (ABC) transporter family, and zinT, which encodes a periplasmic zinc-binding protein. The expression of znuABC and zinT was inducible when cells were grown in medium containing a metal chelator (EDTA), and this induction was shown to be specific for zinc depletion. The expression of znuABC was reduced in response to increased zinc in a dose-dependent manner, and zinT had a less pronounced but similar pattern of zinc-regulated expression. The inactivation of zur led to constitutively high expression of znuABC and zinT. In addition, a zur mutant had an increased total zinc content compared to the WT NTL4 strain, whereas the inactivation of zinT caused a reduction in the total zinc content. The zinT gene is shown to play a dominant role and to be more important than znuA and znuB for A. tumefaciens survival under zinc deprivation. ZinT can function even when ZnuABC is inactivated. However, mutations in zur, znuA, znuB or zinT did not affect the virulence of A. tumefaciens. PMID:25227896

  15. Zinc as an anti-tumor agent in prostate cancer and in other cancers.

    PubMed

    Franklin, Renty B; Costello, Leslie C

    2007-07-15

    Human prostate glandular epithelial cells have the unique capability of accumulating high levels of zinc. This is essential to inhibit m-aconitase activity so that citrate can accumulate for secretion into prostatic fluid, which is a major function of the prostate gland. As a result, the Krebs cycle is truncated with the consequence of the lost ATP production that would result from citrate oxidation. The cellular accumulation of zinc also inhibits mitochondrial terminal oxidation and respiration. In addition to these metabolic effects, zinc accumulation exhibits anti-proliferative effects via its induction of mitochondrial apoptogenesis. Zinc accumulation also inhibits the invasive/migration activities in malignant prostate cells. The anti-proliferative effects and the effects on invasion and migration occur through zinc activation of specific intracellular signaling pathways. Consequently, these effects impose anti-tumor actions by zinc. The ability of prostate cells to accumulate zinc is due to the expression and activity of the zinc uptake transporter, ZIP1. To avoid the anti-tumor effects of zinc, in prostate cancer the malignant prostate cells exhibit a silencing of ZIP1 gene expression accompanied by a depletion of cellular zinc. Therefore we regard ZIP1 as a tumor suppressor gene in prostate cancer. In addition to prostate cells, similar tumor suppressor effects of zinc have been identified in several other types of tumors. PMID:17400177

  16. Zinc: An Essential Micronutrient

    PubMed Central

    SAPER, ROBERT B.; RASH, REBECCA

    2009-01-01

    Zinc is an essential micronutrient for human metabolism that catalyzes more than 100 enzymes, facilitates protein folding, and helps regulate gene expression. Patients with malnutrition, alcoholism, inflammatory bowel disease, and malabsorption syndromes are at an increased risk of zinc deficiency. Symptoms of zinc deficiency are nonspecific, including growth retardation, diarrhea, alopecia, glossitis, nail dystrophy, decreased immunity, and hypogonadism in males. In developing countries, zinc supplementation may be effective for the prevention of upper respiratory infection and diarrhea, and as an adjunct treatment for diarrhea in malnourished children. Zinc in combination with antioxidants may be modestly effective in slowing the progression of intermediate and advanced age-related macular degeneration. Zinc is an effective treatment for Wilson disease. Current data do not support zinc supplementation as effective for upper respiratory infection, wound healing, or human immunodeficiency virus. Zinc is well tolerated at recommended dosages. Adverse effects of long-term high-dose zinc use include suppressed immunity, decreased high-density lipoprotein cholesterol levels, anemia, copper deficiency, and possible genitourinary complications. PMID:20141096

  17. Zinc and Chlamydia trachomatis

    SciTech Connect

    Sugarman, B.; Epps, L.R.

    1985-07-01

    Zinc was noted to have significant effects upon the infection of McCoy cells by each of two strains of Chlamydia trachomatis. With a high or low Chlamydia inoculant, the number of infected cells increased up to 200% utilizing supplemental zinc (up to 1 x 10/sup -4/ M) in the inoculation media compared with standard Chlamydia cultivation media (8 x 10/sup -6/ M zinc). Ferric chloride and calcium chloride did not effect any such changes. Higher concentrations of zinc, after 2 hr of incubation with Chlamydia, significantly decreased the number of inclusions. This direct effect of zinc on the Chlamydia remained constant after further repassage of the Chlamydia without supplemental zinc, suggesting a lethal effect of the zinc. Supplemental zinc (up to 10/sup -4/ M) may prove to be a useful addition to inoculation media to increase the yield of culturing for Chlamydia trachomatis. Similarly, topical or oral zinc preparations used by people may alter their susceptibility to Chamydia trachomatis infections.

  18. Mechanism of the antihypoxic action of zinc compounds

    SciTech Connect

    Uryupov, O.Y.; Sumina, E.N.

    1985-10-01

    This paper studies the mechanism of the protective action of zinc compound in acute carbon monoxide poisoning. The survival rate of animals receiving a preliminary injection of bis (1-vinylimidazole) zinc sulfate before exposure to hypobaric and mormobaric hypoxia was 60% respectively compared with 10 and 15% in the control groups. During CO poisoning the rise of the HbCO level in the blood of mice receiving prophylactic zinc complex was delayed. It is suggested that the antihypoxic effect of the zinc ion is connected with changes in the functional properties of the hemoglobin molecule.

  19. 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

  20. Fully depleted back illuminated CCD

    DOEpatents

    Holland, Stephen Edward

    2001-01-01

    A backside illuminated charge coupled device (CCD) is formed of a relatively thick high resistivity photon sensitive silicon substrate, with frontside electronic circuitry, and an optically transparent backside ohmic contact for applying a backside voltage which is at least sufficient to substantially fully deplete the substrate. A greater bias voltage which overdepletes the substrate may also be applied. One way of applying the bias voltage to the substrate is by physically connecting the voltage source to the ohmic contact. An alternate way of applying the bias voltage to the substrate is to physically connect the voltage source to the frontside of the substrate, at a point outside the depletion region. Thus both frontside and backside contacts can be used for backside biasing to fully deplete the substrate. Also, high resistivity gaps around the CCD channels and electrically floating channel stop regions can be provided in the CCD array around the CCD channels. The CCD array forms an imaging sensor useful in astronomy.

  1. Chelators for investigating zinc metalloneurochemistry.

    PubMed

    Radford, Robert J; Lippard, Stephen J

    2013-04-01

    The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals of hippocampal mossy fiber buttons.

  2. Effective treatment of Wilson's disease with oral zinc sulphate: two case reports.

    PubMed

    Hoogenraad, T U; Van den Hamer, C J; Van Hattum, J

    1984-08-01

    Most patients with Wilson's disease are treated with the potentially toxic cupriuretic agent penicillamine. The toxicity of zinc taken by mouth is low, and long term administration induces a negative copper balance. Two patients with severe neurological symptoms were given zinc sulphate by mouth three times daily in doses of 200 mg, later increased to 300 mg. One patient, a 21 year old man, started to receive zinc sulphate after his condition had deteriorated during treatment with cupriuretic drugs. The other, a 27 year old woman, was treated from the start with zinc sulphate. The conditions of both patients improved appreciably, and they were still receiving treatment with zinc sulphate roughly two years later. Effective depletion of body copper stores was shown by an intravenous radiocopper loading test and liver biopsy. No side effects were found. Wilson's disease may effectively be treated with zinc sulphate alone.

  3. Vimentin filament organization and stress sensing depend on its single cysteine residue and zinc binding

    PubMed Central

    Pérez-Sala, Dolores; Oeste, Clara L.; Martínez, Alma E.; Carrasco, M. Jesús; Garzón, Beatriz; Cañada, F. Javier

    2015-01-01

    The vimentin filament network plays a key role in cell architecture and signalling, as well as in epithelial–mesenchymal transition. Vimentin C328 is targeted by various oxidative modifications, but its role in vimentin organization is not known. Here we show that C328 is essential for vimentin network reorganization in response to oxidants and electrophiles, and is required for optimal vimentin performance in network expansion, lysosomal distribution and aggresome formation. C328 may fulfil these roles through interaction with zinc. In vitro, micromolar zinc protects vimentin from iodoacetamide modification and elicits vimentin polymerization into optically detectable structures; in cells, zinc closely associates with vimentin and its depletion causes reversible filament disassembly. Finally, zinc transport-deficient human fibroblasts show increased vimentin solubility and susceptibility to disruption, which are restored by zinc supplementation. These results unveil a critical role of C328 in vimentin organization and open new perspectives for the regulation of intermediate filaments by zinc. PMID:26031447

  4. Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide

    NASA Astrophysics Data System (ADS)

    Patterson, James D.; Li, Wei-Gang

    1995-03-01

    The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

  5. Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide

    NASA Technical Reports Server (NTRS)

    Patterson, James D.; Li, Wei-Gang

    1995-01-01

    The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

  6. Zinc Inhibits Hedgehog Autoprocessing

    PubMed Central

    Xie, Jian; Owen, Timothy; Xia, Ke; Singh, Ajay Vikram; Tou, Emiley; Li, Lingyun; Arduini, Brigitte; Li, Hongmin; Wan, Leo Q.; Callahan, Brian; Wang, Chunyu

    2015-01-01

    Zinc is an essential trace element with wide-ranging biological functions, whereas the Hedgehog (Hh) signaling pathway plays crucial roles in both development and disease. Here we show that there is a mechanistic link between zinc and Hh signaling. The upstream activator of Hh signaling, the Hh ligand, originates from Hh autoprocessing, which converts the Hh precursor protein to the Hh ligand. In an in vitro Hh autoprocessing assay we show that zinc inhibits Hh autoprocessing with a Ki of 2 μm. We then demonstrate that zinc inhibits Hh autoprocessing in a cellular environment with experiments in primary rat astrocyte culture. Solution NMR reveals that zinc binds the active site residues of the Hh autoprocessing domain to inhibit autoprocessing, and isothermal titration calorimetry provided the thermodynamics of the binding. In normal physiology, zinc likely acts as a negative regulator of Hh autoprocessing and inhibits the generation of Hh ligand and Hh signaling. In many diseases, zinc deficiency and elevated level of Hh ligand co-exist, including prostate cancer, lung cancer, ovarian cancer, and autism. Our data suggest a causal relationship between zinc deficiency and the overproduction of Hh ligand. PMID:25787080

  7. Preparation of zinc orthotitanate

    NASA Technical Reports Server (NTRS)

    Gates, D. W.; Gilligan, J. E.; Harada, Y.; Logan, W. R.

    1977-01-01

    Use of decomposable precursors to enhance zinc oxide-titanium dioxide reaction and rapid fixing results in rapid preparation of zinc orthotitanate powder pigment. Preparation process allows production under less stringent conditions. Elimination of powder grinding results in purer that is less susceptible to color degradation.

  8. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    PubMed

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  9. [Effects of intercropping Sedum plumbizincicola and Apium graceolens on the soil chemical and microbiological properties under the contamination of zinc and cadmium from sewage sludge application].

    PubMed

    Nai, Feng-Jiao; Wu, Long-Hua; Liu, Hong-Yan; Ren, Jing; Liu, Wu-Xing; Luo, Yong-Ming

    2013-05-01

    Taking the vegetable soil with zinc- and cadmium contamination from a long-term sewage sludge application as the object, a pot experiment was conducted to study the remediation effect of Sedum plumbizincicola and Apium graceolens under continuous monoculture and intercropping. With the remediation time increased, both S. plumbizincicola and A. graceolens under monoculture grew poorly, but S. plumbizincicola under intercropping grew well. Under intercropping, the soil organic matter, total N, extractable N, and total P contents decreased significantly while the soil extractable K content had a significant increase, the counts of soil bacteria and fungi increased by 7.9 and 18.4 times and 3.7 and 4.3 times, respectively, but the soil urease and catalase activities remained unchanged, as compared with those under A. graceolens and S. plumbizincicola monoculture. The BIOLOG ECO micro-plates also showed that the carbon sources utilization level and the functional diversity index of soil microbial communities were higher under intercropping than under monoculture, and the concentrations of soil zinc and cadmium under intercropping decreased by 5.8% and 50.0%, respectively, with the decrements being significantly higher than those under monoculture. It was suggested that soil microbial effect could be one of the important factors affecting plant growth.

  10. Synthesis, crystal structure and spectroscopic and electrochemical properties of bridged trisbenzoato copper-zinc heterobinuclear complex of 2,2‧-bipyridine

    NASA Astrophysics Data System (ADS)

    Koch, Angira; Kumar, Arvind; Singh, Suryabhan; Borthakur, Rosmita; Basumatary, Debajani; Lal, Ram A.; Shangpung, Sankey

    2015-03-01

    The synthesis of the heterobinuclear copper-zinc complex [CuZn(bz)3(bpy)2]ClO4 (bz = benzoate) from benzoic acid and bipyridine is described. Single crystal X-ray diffraction studies of the heterobinuclear complex reveals the geometry of the benzoato bridged Cu(II)-Zn(II) centre. The copper or zinc atom is pentacoordinate, with two oxygen atoms from bridging benzoato groups and two nitrogen atoms from one bipyridine forming an approximate plane and a bridging oxygen atom from a monodentate benzoate group. The Cu-Zn distance is 3.345 Å. The complex is normal paramagnetic having μeff value equal to 1.75 BM, ruling out the possibility of Cu-Cu interaction in the structural unit. The ESR spectrum of the complex in CH3CN at RT exhibit an isotropic four line spectrum centred at g = 2.142 and hyperfine coupling constants Aav = 63 × 10-4 cm-1, characteristic of a mononuclear square-pyramidal copper(II) complexes. At LNT, the complex shows an isotropic spectrum with g|| = 2.254 and g⊥ = 2.071 and A|| = 160 × 10-4 cm-1. The Hamiltonian parameters are characteristic of distorted square pyramidal geometry. Cyclic voltammetric studies of the complex have indicated quasi-reversible behaviour in acetonitrile solution.

  11. Crystal structure, DNA binding studies, nucleolytic property and topoisomerase I inhibition of zinc complex with 1,10-phenanthroline and 3-methyl-picolinic acid.

    PubMed

    Seng, Hoi-Ling; Von, Sze-Tin; Tan, Kong-Wai; Maah, Mohd Jamil; Ng, Seik-Weng; Rahman, Raja Noor Zaliha Raja Abd; Caracelli, Ignez; Ng, Chew-Hee

    2010-02-01

    Crystal structure analysis of the zinc complex establishes it as a distorted octahedral complex, bis(3-methylpicolinato-kappa(2) N,O)(2)(1,10-phenanthroline-kappa(2) N,N)-zinc(II) pentahydrate, [Zn(3-Me-pic)(2)(phen)]x5H(2)O. The trans-configuration of carbonyl oxygen atoms of the carboxylate moieties and orientation of the two planar picolinate ligands above and before the phen ligand plane seems to confer DNA sequence recognition to the complex. It cannot cleave DNA under hydrolytic condition but can slightly be activated by hydrogen peroxide or sodium ascorbate. Circular Dichroism and Fluorescence spectroscopic analysis of its interaction with various duplex polynucleotides reveals its binding mode as mainly intercalation. It shows distinct DNA sequence binding selectivity and the order of decreasing selectivity is ATAT > AATT > CGCG. Docking studies lead to the same conclusion on this sequence selectivity. It binds strongly with G-quadruplex with human tolemeric sequence 5'-AG(3)(T(2)AG(3))(3)-3', can inhibit topoisomerase I efficiently and is cytotoxic against MCF-7 cell line.

  12. Self-assembly of zinc polymers based on a flexible linear ligand at different pH values: Syntheses, structures and fluorescent properties

    NASA Astrophysics Data System (ADS)

    Xu, Yan-Hong; Lan, Ya-Qian; Wang, Xin-Long; Zang, Hong-Ying; Shao, Kui-Zhan; Liao, Yi; Su, Zhong-Min

    2009-03-01

    Five novel coordination polymers, [Zn(imbz) 2] n ( 1), {[Zn(imbz) 2]·H 2O} n ( 2), [Zn(imbz)( μ2-OH)] n ( 3), [Zn 3(imbt) 2( p-bdc) 3] n ( 4), [Zn 4( μ3-OH) 2(imbt) 2( p-bdc) 3] n ( 5), (imbt = 4'-(imidazol-1-ylmethyl)benzonitrile, imbz - = 4'-(imidazol-1-ylmethyl)benzoate and p-bdc = terephthalic acid) have been hydrothermally prepared through systematically changing the pH values of reaction mixture, and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. Compounds 1 and 2 exhibit similar 2D (4,4) grid structures, whereas compound 2 contains a right-handed helix along b-axis. Compound 3 has a distorted diamond framework which was constructed via imbz - ligands and μ2-OH groups linking metal atoms. Compound 4 shows a 2D 6-connected network with trinuclear zinc clusters as secondary building units (SBUs), whereas 5 shows a distorted α-Po with tetranuclear zinc clusters as SBUs, in which p-bdc ligands act as bridges. Moreover, compounds 1- 5 all exhibit strong blue photoluminescence in the solid state at room temperature.

  13. Characterization of the Zn(II) binding properties of the human Wilms' tumor suppressor protein C-terminal zinc finger peptide.

    PubMed

    Chan, Ka Lam; Bakman, Inna; Marts, Amy R; Batir, Yuksel; Dowd, Terry L; Tierney, David L; Gibney, Brian R

    2014-06-16

    Zinc finger proteins that bind Zn(II) using a Cys2His2 coordination motif within a ββα protein fold are the most abundant DNA binding transcription factor domains in eukaryotic systems. These classic zinc fingers are typically unfolded in the apo state and spontaneously fold into their functional ββα folds upon incorporation of Zn(II). These metal-induced protein folding events obscure the free energy cost of protein folding by coupling the protein folding and metal-ion binding thermodynamics. Herein, we determine the formation constant of a Cys2His2/ββα zinc finger domain, the C-terminal finger of the Wilms' tumor suppressor protein (WT1-4), for the purposes of determining its free energy cost of protein folding. Measurements of individual conditional dissociation constants, Kd values, at pH values from 5 to 9 were determined using fluorescence spectroscopy by direct or competition titration. Potentiometric titrations of apo-WT1-4 followed by NMR spectroscopy provided the intrinsic pKa values of the Cys2His2 residues, and corresponding potentiometric titrations of Zn(II)-WT1-4 followed by fluorescence spectroscopy yielded the effective pKa(eff) values of the Cys2His2 ligands bound to Zn(II). The Kd, pKa, and pKa(eff) values were combined in a minimal, complete equilibrium model to yield the pH-independent formation constant value for Zn(II)-WT1-4, Kf(ML) value of 7.5 × 10(12) M(-1), with a limiting Kd value of 133 fM. This shows that Zn(II) binding to the Cys2His2 site in WT1-4 provides at least -17.6 kcal/mol in driving force to fold the protein scaffold. A comparison of the conditional dissociation constants of Zn(II)-WT1-4 to those from the model peptide Zn(II)-GGG-Cys2His2 over the pH range 5.0 to 9.0 and a comparison of their pH-independent Kf(ML) values demonstrates that the free energy cost of protein folding in WT1-4 is less than +2.1 kcal/mol. These results validate our GGG model system for determining the cost of protein folding in natural zinc

  14. Characterization of the Zn(II) binding properties of the human Wilms' tumor suppressor protein C-terminal zinc finger peptide.

    PubMed

    Chan, Ka Lam; Bakman, Inna; Marts, Amy R; Batir, Yuksel; Dowd, Terry L; Tierney, David L; Gibney, Brian R

    2014-06-16

    Zinc finger proteins that bind Zn(II) using a Cys2His2 coordination motif within a ββα protein fold are the most abundant DNA binding transcription factor domains in eukaryotic systems. These classic zinc fingers are typically unfolded in the apo state and spontaneously fold into their functional ββα folds upon incorporation of Zn(II). These metal-induced protein folding events obscure the free energy cost of protein folding by coupling the protein folding and metal-ion binding thermodynamics. Herein, we determine the formation constant of a Cys2His2/ββα zinc finger domain, the C-terminal finger of the Wilms' tumor suppressor protein (WT1-4), for the purposes of determining its free energy cost of protein folding. Measurements of individual conditional dissociation constants, Kd values, at pH values from 5 to 9 were determined using fluorescence spectroscopy by direct or competition titration. Potentiometric titrations of apo-WT1-4 followed by NMR spectroscopy provided the intrinsic pKa values of the Cys2His2 residues, and corresponding potentiometric titrations of Zn(II)-WT1-4 followed by fluorescence spectroscopy yielded the effective pKa(eff) values of the Cys2His2 ligands bound to Zn(II). The Kd, pKa, and pKa(eff) values were combined in a minimal, complete equilibrium model to yield the pH-independent formation constant value for Zn(II)-WT1-4, Kf(ML) value of 7.5 × 10(12) M(-1), with a limiting Kd value of 133 fM. This shows that Zn(II) binding to the Cys2His2 site in WT1-4 provides at least -17.6 kcal/mol in driving force to fold the protein scaffold. A comparison of the conditional dissociation constants of Zn(II)-WT1-4 to those from the model peptide Zn(II)-GGG-Cys2His2 over the pH range 5.0 to 9.0 and a comparison of their pH-independent Kf(ML) values demonstrates that the free energy cost of protein folding in WT1-4 is less than +2.1 kcal/mol. These results validate our GGG model system for determining the cost of protein folding in natural zinc

  15. Zinc sensing by metal-responsive transcription factor 1 (MTF1) controls metallothionein and ZnT1 expression to buffer the sensitivity of the transcriptome response to zinc.

    PubMed

    Hardyman, J E J; Tyson, J; Jackson, K A; Aldridge, C; Cockell, S J; Wakeling, L A; Valentine, R A; Ford, D

    2016-03-01

    Only a small number of genes are known direct targets of the zinc-responsive transcription factor MTF1; therefore, the aim of this study was to gain a more complete understanding of the MTF-1 regulated zinc-responsive component of the transcriptome. A targeted siRNA was used to deplete MTF1 expression in the human intestinal cell line Caco-2. We predicted that the response to zinc of direct MTF1 target genes would be abrogated by MTF1 knockdown. Surprisingly, a greater number of genes were regulated by zinc following MFT1 knockdown, and most genes that responded to zinc under both control and MTF1-depleted conditions had an augmented response in the latter condition. Exceptions were the zinc effluxer ZnT1 and a suite of metallothionein genes, suggesting that responses of other genes to zinc are usually buffered by increases in these proteins. We propose that MTF1 heads a hierarchy of zinc sensors, and through controlling the expression of a raft of metallothioneins and other key proteins involved in controlling intracellular zinc levels (e.g. ZnT1) alters zinc buffering capacity and total cellular zinc content. We tested and validated this model by overexpressing metallothionein and observing the predicted curtailment in response of the zinc-repressed SLC30A5 (ZnT5) promoter. The model provides the framework for an integrated understanding of cellular zinc homeostasis. Because MTs can bind metals other than zinc, this framework links with overall cellular metal homeostasis. PMID:26824222

  16. 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

  17. Exploring zinc coordination in novel zinc battery electrolytes.

    PubMed

    Kar, Mega; Winther-Jensen, Bjorn; Forsyth, Maria; MacFarlane, Douglas R

    2014-06-14

    The coordination of zinc ions by tetraglyme has been investigated here to support the development of novel electrolytes for rechargeable zinc batteries. Zn(2+) reduction is electrochemically reversible from tetraglyme. The spectroscopic data, molar conductivity and thermal behavior as a function of zinc composition, between mole ratios [80 : 20] and [50 : 50] [tetraglyme : zinc chloride], all suggest that strong interactions take place between chloro-zinc complexes and tetraglyme. Varying the concentration of zinc chloride produces a range of zinc-chloro species (ZnClx)(2-x) in solution, which hinder full interaction between the zinc ion and tetraglyme. Both the [70 : 30] and [50 : 50] mixtures are promising electrolyte candidates for reversible zinc batteries, such as the zinc-air device.

  18. Exploring zinc coordination in novel zinc battery electrolytes.

    PubMed

    Kar, Mega; Winther-Jensen, Bjorn; Forsyth, Maria; MacFarlane, Douglas R

    2014-06-14

    The coordination of zinc ions by tetraglyme has been investigated here to support the development of novel electrolytes for rechargeable zinc batteries. Zn(2+) reduction is electrochemically reversible from tetraglyme. The spectroscopic data, molar conductivity and thermal behavior as a function of zinc composition, between mole ratios [80 : 20] and [50 : 50] [tetraglyme : zinc chloride], all suggest that strong interactions take place between chloro-zinc complexes and tetraglyme. Varying the concentration of zinc chloride produces a range of zinc-chloro species (ZnClx)(2-x) in solution, which hinder full interaction between the zinc ion and tetraglyme. Both the [70 : 30] and [50 : 50] mixtures are promising electrolyte candidates for reversible zinc batteries, such as the zinc-air device. PMID:24760367

  19. Competitive interaction of iron and zinc in the diet: consequences for human nutrition

    SciTech Connect

    Solomons, N.W.

    1986-06-01

    The degree to which inhibitors of zinc bioavailability actually influence the zinc status of humans who consume usual meals and diets is not known. The interaction of iron and zinc and competitive inhibition of zinc uptake by excess iron in ratios of 2:1 or greater, when the total amount of ionic species is greater than 25 mg, appear to have a measurable effect on human zinc nutrition. The physiological basis is the competition of these chemically similar ions for some portions of a common absorptive pathway shared between inorganic (nonheme) iron and zinc; this has been demonstrated in animal experiments and in zinc absorption studies in human volunteers. Thus, studies involving formula-fed infants, experimental zinc-depletion diets and pregnant women who took prenatal vitamin-mineral supplements containing high levels of iron have shown growth delay (infants) and a decreased circulating zinc pool (all age groups), suggesting a determinant impact of excessively high Fe/Zn ratios in the diet. Consideration of solutions to these problems, including conscious adjustment of the Fe/Zn ratios in human diets, foods and therapeutic nutrient supplements in order to reduce the zinc-inhibiting effects of iron, should become a priority in policy and marketing discussions within government regulatory agencies, industry and the scientific community of human and clinical nutritionists. 50 references.

  20. Zinc Supplementation Prevents Alcoholic Liver Injury in Mice through Attenuation of Oxidative Stress

    PubMed Central

    Zhou, Zhanxiang; Wang, Lipeng; Song, Zhenyuan; Saari, Jack T.; McClain, Craig J.; Kang, Y. James

    2005-01-01

    Alcoholic liver disease is associated with zinc decrease in the liver. Therefore, we examined whether dietary zinc supplementation could provide protection from alcoholic liver injury. Metallothionein-knockout and wild-type 129/Sv mice were pair-fed an ethanol-containing liquid diet for 12 weeks, and the effects of zinc supplementation on ethanol-induced liver injury were analyzed. Zinc supplementation attenuated ethanol-induced hepatic zinc depletion and liver injury as measured by histopathological and ultrastructural changes, serum alanine transferase activity, and hepatic tumor necrosis factor-α in both metallothionein-knockout and wild-type mice, indicating a metallothionein-independent zinc protection. Zinc supplementation inhibited accumulation of reactive oxygen species, as indicated by dihydroethidium fluorescence, and the consequent oxidative damage, as assessed by immunohistochemical detection of 4-hydroxynonenal and nitrotyrosine and quantitative analysis of malondialdehyde and protein carbonyl in the liver. Zinc supplementation suppressed ethanol-elevated cytochrome P450 2E1 activity but increased the activity of alcohol dehydrogenase in the liver, without affecting the rate of blood ethanol elimination. Zinc supplementation also prevented ethanol-induced decreases in glutathione concentration and glutathione peroxidase activity and increased glutathione reductase activity in the liver. In conclusion, zinc supplementation prevents alcoholic liver injury in an metallothionein-independent manner by inhibiting the generation of reactive oxygen species (P450 2E1) and enhancing the activity of antioxidant pathways. PMID:15920153