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Sample records for zinc oxide azo

  1. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode

    PubMed Central

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-01-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films. PMID:26515670

  2. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode

    NASA Astrophysics Data System (ADS)

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-10-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films.

  3. 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.

  4. Aluminum doped zinc oxide for organic photovoltaics

    SciTech Connect

    Murdoch, G. B.; Hinds, S.; Sargent, E. H.; Tsang, S. W.; Mordoukhovski, L.; Lu, Z. H.

    2009-05-25

    Aluminum doped zinc oxide (AZO) was grown via magnetron sputtering as a low-cost alternative to indium tin oxide (ITO) for organic photovoltaics (OPVs). Postdeposition ozone treatment resulted in devices with lower series resistance, increased open-circuit voltage, and power conversion efficiency double that of devices fabricated on untreated AZO. Furthermore, cells fabricated using ozone treated AZO and standard ITO displayed comparable performance.

  5. 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 ...

  6. Ion beam fabrication of aluminum-doped zinc oxide layer for high-performance liquid crystals alignment.

    PubMed

    Liu, Yang; Lee, Ju Hwan; Seo, Dae-Shik

    2016-07-25

    In this paper, a 1.8 keV ion beam (IB) sputtered thin layer of aluminum-doped zinc oxide (AZO) with columnar AZO bumps covering the surface working as an alignment layer for the homogeneous alignment of liquid crystals (LC) is investigated. Bumpy AZO alignment layers in twisted nematic (TN) cells generated larger LC pre-tilt angles and thus enabled accelerated switching of LC, and the highly conductive bumpy AZO thin layers allowed super-fast release of accumulated charges, and led to low residual DC performance. These results indicate the promising applications of AZO bumps layer as alignment layer in LC devices. PMID:27464189

  7. Doped zinc oxide microspheres

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  8. Doped zinc oxide microspheres

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  9. Arsenic doped zinc oxide

    SciTech Connect

    Volbers, N.; Lautenschlaeger, S.; Leichtweiss, T.; Laufer, A.; Graubner, S.; Meyer, B. K.; Potzger, K.; Zhou Shengqiang

    2008-06-15

    As-doping of zinc oxide has been approached by ion implantation and chemical vapor deposition. The effect of thermal annealing on the implanted samples has been investigated by using secondary ion mass spectrometry and Rutherford backscattering/channeling geometry. The crystal damage, the distribution of the arsenic, the diffusion of impurities, and the formation of secondary phases is discussed. For the thin films grown by vapor deposition, the composition has been determined with regard to the growth parameters. The bonding state of arsenic was investigated for both series of samples using x-ray photoelectron spectroscopy.

  10. Zinc Oxide Nanophotonics

    NASA Astrophysics Data System (ADS)

    Choi, Sumin; Aharonovich, Igor

    2015-12-01

    The emerging field of nanophotonics initiated a dedicated study of single photon sources and optical resonators in new class of materials. One such material is zinc oxide (ZnO) that has been long considered only for classical light-emitting applications. However, it recently showed promise for quantum photonics technologies. In this review, we highlight the recent advances in studying single emitters in ZnO, engineering of optical cavities and practical nanophotonics devices including nanolasers and electrically triggered devices. We finalize with an outlook at this promising area, as well as provide perspectives and open questions in solid state nanophotonics employing ZnO.

  11. 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

  12. 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.

  13. Interstitial zinc clusters in zinc oxide

    NASA Astrophysics Data System (ADS)

    Gluba, M. A.; Nickel, N. H.; Karpensky, N.

    2013-12-01

    Doped zinc oxide (ZnO) exhibits anomalous Raman modes in the range of 270 to 870 cm-1. Commonly, the resonance at 275 cm-1 is attributed to the local vibration of Zn atoms in the vicinity of extrinsic dopants. We revisit this assignment by investigating the influence of isotopically purified zinc oxide thin films on the frequency of the vibrational mode around 275 cm-1. For this purpose, undoped and nitrogen-doped ZnO thin-films with Zn isotope compositions of natural Zn, 64Zn, 68Zn, and a 1:1 mixture of 64Zn and 68Zn were grown by pulsed laser deposition. The isotopic shift and the line shape of the Raman resonance around 275 cm-1 are analyzed in terms of three different microscopic models, which involve the vibration of (i) interstitial zinc atoms bound to extrinsic defects, (ii) interstitial diatomic Zn molecules, and (iii) interstitial zinc clusters. The energy diagram of interstitial Zn-Zn bonds in a ZnO matrix is derived from density functional theory calculations. The interstitial Zn-Zn bond is stabilized by transferring electrons from the antibonding orbital into the ZnO conduction band. This mechanism facilitates the formation of interstitial Zn clusters and fosters the common n-type doping asymmetry of ZnO.

  14. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  15. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  16. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  17. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  18. 21 CFR 73.1991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Zinc oxide. 73.1991 Section 73.1991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc... indirect process whereby zinc metal isolated from the zinc-containing ore is vaporized and then...

  19. Zinc oxide varistors and/or resistors

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    Varistors and/or resistors that includes doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

  20. Zinc oxide varistors and/or resistors

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-07-27

    Varistors and/or resistors are described that include doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

  1. Zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Chik, Hope Wuming

    Non-lithographic, bottom-up techniques have been developed to advance the state of the art and contribute to the development of new material structures, fabrication methods, devices, and applications using the Zinc Oxide material system as a demonstration vehicle. The novel low temperature catalytic vapour-liquid-solid growth process developed is technologically simple, inexpensive, and a robust fabrication technique offering complete control over the physical dimensions of the nanorod such as its diameter and length, and over the positioning of the nanorods for site-selective growth. By controlling the distribution of the Au catalysts with the use of a self-organized anodized aluminum oxide nanopore membrane as a template, we have been able to synthesize highly ordered, hexagonally packed, array of ZnO nanorods spanning a large area. These nanorods are single crystal, hexagonally shaped, indicative of the wurtzite structure, and are vertically aligned to the substrate. By pre-patterning the template, arbitrary nanorod patterns can be formed. We have also demonstrated the assembly of the nanorods into functional devices using controlled methods that are less resource intensive, easily scalable, and adaptable to other material systems, without resorting to the manipulation of each individual nanostructures. Examples of these devices include the random network device that exploits the common attributes of the nanorods, and those formed using an external field to control the nanorod orientation. Two and three terminal device measurements show that the as-grown nanorods are n-type doped, and that by controlling the external optical excitation and its test environment, the photoconductivity can be altered dramatically. Self assemble techniques such as the spontaneous formation of nanodendrites into complex networks of interconnects were studied. Controlled formation of interconnects achieved by controlling the placement of the catalyst is demonstrated by growing the

  2. 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.

  3. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  4. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  5. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is generally recognized as safe when used...

  6. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is generally recognized as safe when used...

  7. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  8. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  9. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  10. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  11. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  12. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of...

  13. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Zinc oxide. 182.8991 Section 182.8991 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is generally recognized as safe when used...

  14. 21 CFR 73.2991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Zinc oxide. 73.2991 Section 73.2991 Food and Drugs... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in identity and specifications to the requirements of §...

  15. 21 CFR 182.8991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Zinc oxide. 182.8991 Section 182.8991 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is generally recognized as safe when used...

  16. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This substance is...

  17. Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide

    SciTech Connect

    Russo, V.; Ghidelli, M.; Gondoni, P.

    2014-02-21

    In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

  18. High-Quality, Ultraconformal Aluminum-Doped Zinc Oxide Nanoplasmonic and Hyperbolic Metamaterials.

    PubMed

    Riley, Conor T; Smalley, Joseph S T; Post, Kirk W; Basov, Dimitri N; Fainman, Yeshaiahu; Wang, Deli; Liu, Zhaowei; Sirbuly, Donald J

    2016-02-17

    Aluminum-doped zinc oxide (AZO) is a tunable low-loss plasmonic material capable of supporting dopant concentrations high enough to operate at telecommunication wavelengths. Due to its ultrahigh conformality and compatibility with semiconductor processing, atomic layer deposition (ALD) is a powerful tool for many plasmonic applications. However, despite many attempts, high-quality AZO with a plasma frequency below 1550 nm has not yet been realized by ALD. Here a simple procedure is devised to tune the optical constants of AZO and enable plasmonic activity at 1550 nm with low loss. The highly conformal nature of ALD is also exploited to coat silicon nanopillars to create localized surface plasmon resonances that are tunable by adjusting the aluminum concentration, thermal conditions, and the use of a ZnO buffer layer. The high-quality AZO is then used to make a layered AZO/ZnO structure that displays negative refraction in the telecommunication wavelength region due to hyperbolic dispersion. Finally, a novel synthetic scheme is demonstrated to create AZO embedded nanowires in ZnO, which also exhibits hyperbolic dispersion. PMID:26715115

  19. High-Quality, Ultraconformal Aluminum-Doped Zinc Oxide Nanoplasmonic and Hyperbolic Metamaterials.

    PubMed

    Riley, Conor T; Smalley, Joseph S T; Post, Kirk W; Basov, Dimitri N; Fainman, Yeshaiahu; Wang, Deli; Liu, Zhaowei; Sirbuly, Donald J

    2016-02-17

    Aluminum-doped zinc oxide (AZO) is a tunable low-loss plasmonic material capable of supporting dopant concentrations high enough to operate at telecommunication wavelengths. Due to its ultrahigh conformality and compatibility with semiconductor processing, atomic layer deposition (ALD) is a powerful tool for many plasmonic applications. However, despite many attempts, high-quality AZO with a plasma frequency below 1550 nm has not yet been realized by ALD. Here a simple procedure is devised to tune the optical constants of AZO and enable plasmonic activity at 1550 nm with low loss. The highly conformal nature of ALD is also exploited to coat silicon nanopillars to create localized surface plasmon resonances that are tunable by adjusting the aluminum concentration, thermal conditions, and the use of a ZnO buffer layer. The high-quality AZO is then used to make a layered AZO/ZnO structure that displays negative refraction in the telecommunication wavelength region due to hyperbolic dispersion. Finally, a novel synthetic scheme is demonstrated to create AZO embedded nanowires in ZnO, which also exhibits hyperbolic dispersion.

  20. Oxide Solar Cells Fabricated Using Zinc Oxide and Plasma-Oxidized Cuprous Oxide

    NASA Astrophysics Data System (ADS)

    Chan, Yi-Ming; Wu, Ya-Ting; Jou, Shyankay

    2012-12-01

    Oxide heterojunction solar cells composed of an n-type Al-doped ZnO (AZO) thin film on the surfaces of p-type Cu2O films were fabricated. The Cu2O films of about 0.34 to 1.67 µm thickness were grown by partial oxidation of a Cu sheet using microwave plasma. The AZO film of 400 nm thickness was deposited by magnetron sputtering. Energy conversion efficiencies of 0.12 to 0.30% were obtained in AZO/Cu2O cells under AM1.5 solar illumination.

  1. 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.

  2. Aluminum-Doped Zinc Oxide as Highly Stable Electron Collection Layer for Perovskite Solar Cells.

    PubMed

    Zhao, Xingyue; Shen, Heping; Zhang, Ye; Li, Xin; Zhao, Xiaochong; Tai, Meiqian; Li, Jingfeng; Li, Jianbao; Li, Xin; Lin, Hong

    2016-03-01

    Although low-temperature, solution-processed zinc oxide (ZnO) has been widely adopted as the electron collection layer (ECL) in perovskite solar cells (PSCs) because of its simple synthesis and excellent electrical properties such as high charge mobility, the thermal stability of the perovskite films deposited atop ZnO layer remains as a major issue. Herein, we addressed this problem by employing aluminum-doped zinc oxide (AZO) as the ECL and obtained extraordinarily thermally stable perovskite layers. The improvement of the thermal stability was ascribed to diminish of the Lewis acid-base chemical reaction between perovskite and ECL. Notably, the outstanding transmittance and conductivity also render AZO layer as an ideal candidate for transparent conductive electrodes, which enables a simplified cell structure featuring glass/AZO/perovskite/Spiro-OMeTAD/Au. Optimization of the perovskite layer leads to an excellent and repeatable photovoltaic performance, with the champion cell exhibiting an open-circuit voltage (Voc) of 0.94 V, a short-circuit current (Jsc) of 20.2 mA cm(-2), a fill factor (FF) of 0.67, and an overall power conversion efficiency (PCE) of 12.6% under standard 1 sun illumination. It was also revealed by steady-state and time-resolved photoluminescence that the AZO/perovskite interface resulted in less quenching than that between perovskite and hole transport material. PMID:26960451

  3. Aluminum-Doped Zinc Oxide as Highly Stable Electron Collection Layer for Perovskite Solar Cells.

    PubMed

    Zhao, Xingyue; Shen, Heping; Zhang, Ye; Li, Xin; Zhao, Xiaochong; Tai, Meiqian; Li, Jingfeng; Li, Jianbao; Li, Xin; Lin, Hong

    2016-03-01

    Although low-temperature, solution-processed zinc oxide (ZnO) has been widely adopted as the electron collection layer (ECL) in perovskite solar cells (PSCs) because of its simple synthesis and excellent electrical properties such as high charge mobility, the thermal stability of the perovskite films deposited atop ZnO layer remains as a major issue. Herein, we addressed this problem by employing aluminum-doped zinc oxide (AZO) as the ECL and obtained extraordinarily thermally stable perovskite layers. The improvement of the thermal stability was ascribed to diminish of the Lewis acid-base chemical reaction between perovskite and ECL. Notably, the outstanding transmittance and conductivity also render AZO layer as an ideal candidate for transparent conductive electrodes, which enables a simplified cell structure featuring glass/AZO/perovskite/Spiro-OMeTAD/Au. Optimization of the perovskite layer leads to an excellent and repeatable photovoltaic performance, with the champion cell exhibiting an open-circuit voltage (Voc) of 0.94 V, a short-circuit current (Jsc) of 20.2 mA cm(-2), a fill factor (FF) of 0.67, and an overall power conversion efficiency (PCE) of 12.6% under standard 1 sun illumination. It was also revealed by steady-state and time-resolved photoluminescence that the AZO/perovskite interface resulted in less quenching than that between perovskite and hole transport material.

  4. Zinc hydroxide sulphate and its transformation to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael B; McDonagh, Andrew M

    2013-10-28

    The thermal transformation of zinc hydroxide sulphate hydrate to zinc oxide has been examined using synchrotron X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. By collecting X-ray diffraction data in situ, we found that the dehydration of zinc hydroxide sulphate pentahydrate proceeded in discrete steps to form anhydrous zinc hydroxide sulphate. This compound then decomposed to a mixture of zinc oxide and a compound tentatively identified as Zn3(OH)2(SO4)2 at ~235 °C. At ~360 °C, the final dehydroxylation occurred with the formation of zinc oxy-sulphate, Zn3O(SO4)2, which then decomposed to ZnO at about ~800 °C. Interruption of the dehydration process can be used to synthesize the intermediate compounds.

  5. Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer

    SciTech Connect

    Chen, Dazheng; Zhang, Chunfu Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

    2014-06-16

    Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C{sub 61} butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

  6. Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer

    NASA Astrophysics Data System (ADS)

    Chen, Dazheng; Zhang, Chunfu; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

    2014-06-01

    Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C61 butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

  7. Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

    SciTech Connect

    Shasti, M.; Mortezaali, A. Dariani, R. S.

    2015-01-14

    In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

  8. On the growth of conductive aluminum doped zinc oxide on 001 strontium titanate single crystals

    NASA Astrophysics Data System (ADS)

    Trinca, L. M.; Galca, A. C.; Aldica, G.; Radu, R.; Mercioniu, I.; Pintilie, L.

    2016-02-01

    Aluminum doped zinc oxide (AZO) thin films were obtained by pulsed laser deposition on (001) SrTiO3 (STO) on a range of substrate temperatures during ablation between 300 °C and 600 °C. A hexagonal system lying on a cubic one should be difficult to be obtained in epitaxial form. The geometrical selection of the AZO growth on (001) STO is not giving a unique preferential orientation. Two orientations, c-axis (along [001]) and 110, have been observed experimentally with different ratios at different substrate temperature. Discussions are made with respect to the temperature dependence of lattice mismatch between the two cases and the cubic surface of the substrate, and to the substrate surface morphology and terminating atomic layer composition. The 110 AZO is the main phase at deposition temperature of 550 °C, while for other substrate temperatures the 001 is the preferential orientation. The conductive character of 110 AZO thin film have been inferred from both ellipsometry spectra and current-voltage measurements. Excepting the samples deposited at 300 °C, the lowest resistivity is recorded for the samples with 110 AZO as the main phase.

  9. Bidirectional reflectance of zinc oxide

    NASA Technical Reports Server (NTRS)

    Scott, R.

    1973-01-01

    This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

  10. Directed spatial organization of zinc oxide nanostructures

    DOEpatents

    Hsu, Julia; Liu, Jun

    2009-02-17

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

  11. Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

    2016-04-25

    Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process. PMID:27030646

  12. The azo dye Disperse Red 13 and its oxidation and reduction products showed mutagenic potential.

    PubMed

    Chequer, Farah Maria Drumond; Lizier, Thiago Mescoloto; de Felício, Rafael; Zanoni, Maria Valnice Boldrin; Debonsi, Hosana Maria; Lopes, Norberto Peporine; de Oliveira, Danielle Palma

    2015-10-01

    Common water pollutants, azo dyes and their degradation products have frequently shown toxicity, including carcinogenic and mutagenic effects, and can induce serious damage in aquatic organisms and humans. In the present study, the mutagenic potential of the azo dye Disperse Red 13 (DR13) was first evaluated using the Micronucleus Assay in human lymphocytes. Subsequently, in order to mimic hepatic biotransformation, controlled potential electrolysis was carried out with a DR13 solution using a Potentiostat/Galvanostat. In addition, a DR13 solution was oxidized using S9 (homogenate of rat liver cells). DR13 oxidation and the reduction products were identified using HPLC-DAD and GC/MS, and their mutagenic potential investigated by way of a Salmonella/microsome assay using TA98 and YG1041 strains, with no S9. The original azo dye DR13 induced chromosomal damage in human lymphocytes, and the respective oxidation and reduction products also showed mutagenic activity, as detected by the Salmonella/microsome assay. Furthermore sulfate 2-[(4-aminophenyl)ethylamino]-ethanol monohydrate, 2-chloro-4-nitro-benzamine, 4-nitro-benzamine and 2-(ethylphenylamine)-ethanol were identified as products of the DR13 reduction/oxidation reactions. Thus it was concluded that the contamination of water effluents with DR13 is a health risk not only due to the dye itself, but also due to the possibility of drinking contaminated water, considering the harmful compounds that can be produced after hepatic biotransformation. PMID:26247324

  13. The azo dye Disperse Red 13 and its oxidation and reduction products showed mutagenic potential.

    PubMed

    Chequer, Farah Maria Drumond; Lizier, Thiago Mescoloto; de Felício, Rafael; Zanoni, Maria Valnice Boldrin; Debonsi, Hosana Maria; Lopes, Norberto Peporine; de Oliveira, Danielle Palma

    2015-10-01

    Common water pollutants, azo dyes and their degradation products have frequently shown toxicity, including carcinogenic and mutagenic effects, and can induce serious damage in aquatic organisms and humans. In the present study, the mutagenic potential of the azo dye Disperse Red 13 (DR13) was first evaluated using the Micronucleus Assay in human lymphocytes. Subsequently, in order to mimic hepatic biotransformation, controlled potential electrolysis was carried out with a DR13 solution using a Potentiostat/Galvanostat. In addition, a DR13 solution was oxidized using S9 (homogenate of rat liver cells). DR13 oxidation and the reduction products were identified using HPLC-DAD and GC/MS, and their mutagenic potential investigated by way of a Salmonella/microsome assay using TA98 and YG1041 strains, with no S9. The original azo dye DR13 induced chromosomal damage in human lymphocytes, and the respective oxidation and reduction products also showed mutagenic activity, as detected by the Salmonella/microsome assay. Furthermore sulfate 2-[(4-aminophenyl)ethylamino]-ethanol monohydrate, 2-chloro-4-nitro-benzamine, 4-nitro-benzamine and 2-(ethylphenylamine)-ethanol were identified as products of the DR13 reduction/oxidation reactions. Thus it was concluded that the contamination of water effluents with DR13 is a health risk not only due to the dye itself, but also due to the possibility of drinking contaminated water, considering the harmful compounds that can be produced after hepatic biotransformation.

  14. Sol-gel deposited aluminum-doped and gallium-doped zinc oxide thin-film transparent conductive electrodes with a protective coating of reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Zhu, Zhaozhao; Mankowski, Trent; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

    2016-04-01

    Using a traditional sol-gel deposition technique, we successfully fabricated aluminum-doped zinc oxide (AZO) and gallium-doped zinc oxide (GZO) thin films on glass substrates. Employing a plasma treatment method as the postannealing process, we produced thin-film transparent conductive electrodes exhibiting excellent optical and electrical properties, with transmittance greater than 90% across the entire visible spectrum and the near-infrared range, as well as good sheet resistance under 200 Ω/sq. More importantly, to improve the resilience of our fabricated thin-film samples at elevated temperatures and in humid environments, we deposited a layer of reduced graphene oxide (rGO) as protective overcoating. The stability of our composite AZO/rGO and GZO/rGO samples improved substantially compared to that of their counterparts with no rGO coating.

  15. 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.

  16. Comparative toxicity of a zinc salt, zinc powder and zinc oxide to Eisenia fetida, Enchytraeus albidus and Folsomia candida.

    PubMed

    Lock, Koen; Janssen, Colin R

    2003-12-01

    The pore water zinc concentration and the calcium chloride extracted zinc fraction are higher in the soils spiked with a zinc salt (ZnCl2) compared to soils spiked with zinc oxide or zinc powder. Based on total zinc concentrations in the soil, the acute toxicity of zinc salt to the compost worm Eisenia fetida, the potworm Enchytraeus albidus and the springtail Folsomia candida was lower compared to zinc oxide and zinc powder. However, when expressed on the basis of pore water concentrations or calcium chloride extracted fractions, acute toxicity was higher for zinc salt, which indicated that dermal uptake via the pore water is not the only route of uptake. Chronic toxicity of zinc salt, zinc oxide and zinc powder was similar when based on total concentrations in the soil which again indicates that the pore water route of uptake is not the only route of exposure but that oral uptake is also important.

  17. Degradation of azo dyes by oxidative processes--laccase and ultrasound treatment.

    PubMed

    Tauber, Michael M; Gübitz, Georg M; Rehorek, Astrid

    2008-07-01

    Azo dyes are of synthetic origin and their environmental fate is not well understood. They are resistant to direct aerobic bacterial degradation and form potentially carcinogenic aromatic amines by reduction of the azo group. This study shows that applying the oxidative processes of enzymatic treatment with laccase and ultrasound treatment, both alone and in combination, leads to dye degradation. Laccase treatment degraded both Acid Orange and Direct Blue dyes within 1-5 h but failed in the case of Reactive dyes, whereas ultrasound degraded all the dyes investigated (3-15 h). When applied as multi-stage combinations the treatments showed synergistic effects for dye degradation compared with individual treatments. Bulk light absorption (UV-Vis) and ion pairing HPLC were used for process monitoring. Additionally, mass spectrometry was used to elucidate the structures of intermediates arising from ultrasound treatment.

  18. Influence of RF power on magnetron sputtered AZO films

    SciTech Connect

    Agarwal, Mohit; Modi, Pankaj; Dusane, R. O.

    2013-02-05

    Al-doped Zinc Oxide (AZO) transparent conducting films are prepared on glass substrate by RF magnetron sputtering under different RF power with a 3 inch diameter target of 2 wt%Al{sub 2}O{sub 3} in zinc oxide. The effect of RF power on the structural, optical and electrical properties of AZO films was investigated by X-ray Diffraction (XRD), Hall measurement and UV-Visible spectrophotometry. The XRD data indicates a preferential c-axis orientation for all the films. All films exhibit high transmittance (<90%) in visible region. Films deposited at 60 W power exhibit lowest resistivity of 5.7 Multiplication-Sign 10{sup -4}{omega}cm. Such low-resistivity and high-transmittance AZO films when prepared using low RF power at room temperature could find important applications in flexible electronics.

  19. Zinc oxide interdigitated electrode for biosensor application

    NASA Astrophysics Data System (ADS)

    Sin L., L.; Arshad, M. K. Md.; Fathil, M. F. M.; Adzhri, R.; M. Nuzaihan M., N.; Ruslinda, A. R.; Gopinath, Subash C. B.; Hashim, U.

    2016-07-01

    In biosensors, zinc oxide (ZnO) thin film plays a crucial role in term of stability, sensitivity, biocompatibility and low cost. Interdigitated electrode (IDE) design is one of the device architecture in biosensor for label free, stability and sensitivity. In this paper, we discuss the fabrication of zinc oxide deposited on the IDE as a transducer for sensing of biomolecule. The formation of APTES had increase the performance of the surface functionalization..Furthermore we extend the discuss on the surface functionalization process which is utilized for probe attachment onto the surface of biosensor through surface immobilization process, thus enables the sensing of biomolecules for biosensor application.

  20. Chlorine dioxide-facilitated oxidation of the azo dye amaranth.

    PubMed

    Nadupalli, S; Koorbanally, N; Jonnalagadda, S B

    2011-10-27

    The oxidation reaction of amaranth (trisodium 2-hydroxy-1-(4-sulfonato-1-naphthylazo)naphthalene-3,6-disulfonate or AM(-)) by chlorine dioxide (ClO(2)) in aqueous conditions was investigated in detail. The major reaction products immediately after decolorization of AM(-) were 1,2-naphthoquinone disulfonate sodium salt and 1,4-napthalenedione. The reaction had first-order dependence on both AM(-) and ClO(2). The rate-limiting step involved the reaction between AM(-) and OH(-) ions. The role of hydroxide ion as a catalyst was established. The second-order rate constant increased with pH, from (19.8 ± 0.9) M(-1) s(-1) at pH 7.0, (97.1 ± 2.3) M(-1) s(-1) at pH 8.0 to (132.5 ± 2.8) M(-1) s(-1) at pH 9.0. In the pH range of 6.0-7.5, the catalytic constant for OH(-) ion was 4.0 × 10(9) M(-2) s(-1). The energy and entropy of activation values for the reaction were 50.0 kJ mol(-1) and -658.7 J K(-1) mol(-1), respectively. A probable reaction mechanism was elucidated and was validated by simulations.

  1. 21 CFR 582.5991 - Zinc oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Zinc oxide. 582.5991 Section 582.5991 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  2. Photoemission studies of wurtzite zinc oxide.

    NASA Technical Reports Server (NTRS)

    Powell, R. A.; Spicer, W. E.; Mcmenamin, J. C.

    1972-01-01

    The electronic structure of wurtzite zinc oxide, investigated over the widest possible photon energy range by means of photoemission techniques, is described. Of particular interest among the results of the photoemission study are the location of the Zn 3rd core states, the width of the upper valence bands, and structure in the conduction-band and valence-band density of states.

  3. 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.

  4. A Back-Gated Ferroelectric Field-Effect Transistor with an Al-Doped Zinc Oxide Channel

    NASA Astrophysics Data System (ADS)

    Jia, Ze; Xu, Jian-Long; Wu, Xiao; Zhang, Ming-Ming; Liou, Juin-J.

    2015-02-01

    We report a back-gated metal-oxide-ferroelectric-metal (MOFM) field-effect transistor (FET) with lead zirconate titanate (PZT) material, in which an Al doped zinc oxide (AZO) channel layer with an optimized doping concentration of 1% is applied to reduce the channel resistance of the channel layer, thus guaranteeing a large enough load capacity of the transistor. The hysteresis loops of the Pt/PZT/AZO/Ti/Pt capacitor are measured and compared with a Pt/PZT/Pt capacitor, indicating that the remnant polarization is almost 40 μC/cm2 and the polarization is saturated at 20 V. The measured capacitance-voltage properties are analyzed as a result of the electron depletion and accumulation switching operation conducted by the modulation of PZT on AZO channel resistance caused by the switchable remnant polarization of PZT. The switching properties of the AZO channel layer are also proved by the current-voltage transfer curves measured in the back-gated MOFM ferroelectric FET, which also show a drain current switching ratio up to about 100 times.

  5. Oxidation of Levafix CA reactive azo-dyes in industrial wastewater of textile dyeing by electro-generated Fenton's reagent.

    PubMed

    El-Desoky, Hanaa S; Ghoneim, Mohamed M; El-Sheikh, Ragaa; Zidan, Naglaa M

    2010-03-15

    The indirect electrochemical removal of pollutants from effluents has become an attractive method in recent years. Removal (decolorization and mineralization) of Levafix Blue CA and Levafix Red CA reactive azo-dyes from aqueous media by electro-generated Fenton's reagent (Fe(2+)/H(2)O(2)) using a reticulated vitreous carbon cathode and a platinum gauze anode was optimized. Progress of oxidation (decolorization and mineralization) of the investigated azo-dyes with time of electro-Fenton's reaction was monitored by UV-visible absorbance measurements, Chemical oxygen demand (COD) removal and HPLC analysis. The results indicated that the electro-Fenton's oxidation system is efficient for treatment of such types of reactive dyes. Oxidation of each of the investigated azo-dyes by electro-generated Fenton's reagent up to complete decolorization and approximately 90-95% mineralization was achieved. Moreover, the optimized electro-Fenton's oxidation was successfully applied for complete decolorization and approximately 85-90% mineralization of both azo-dyes in real industrial wastewater samples collected from textile dyeing house at El-Mahalla El-Kobra, Egypt.

  6. Colloidal infrared reflective and transparent conductive aluminum-doped zinc oxide nanocrystals

    DOEpatents

    Buonsanti, Raffaella; Milliron, Delia J

    2015-02-24

    The present invention provides a method of preparing aluminum-doped zinc oxide (AZO) nanocrystals. In an exemplary embodiment, the method includes (1) injecting a precursor mixture of a zinc precursor, an aluminum precursor, an amine, and a fatty acid in a solution of a vicinal diol in a non-coordinating solvent, thereby resulting in a reaction mixture, (2) precipitating the nanocrystals from the reaction mixture, thereby resulting in a final precipitate, and (3) dissolving the final precipitate in an apolar solvent. The present invention also provides a dispersion. In an exemplary embodiment, the dispersion includes (1) nanocrystals that are well separated from each other, where the nanocrystals are coated with surfactants and (2) an apolar solvent where the nanocrystals are suspended in the apolar solvent. The present invention also provides a film. In an exemplary embodiment, the film includes (1) a substrate and (2) nanocrystals that are evenly distributed on the substrate.

  7. Influence of various thickness metallic interlayers on opto-electric and mechanical properties of AZO thin films on PET substrates

    NASA Astrophysics Data System (ADS)

    Chang, R. C.; Li, T. C.; Lin, C. W.

    2012-02-01

    Various thickness metallic interlayers to improve the opto-electric and mechanical properties of aluminum-doped zinc oxide (AZO) thin films deposited on flexible polyethylene terephtalate (PET) substrates are studied. The effects of the interlayers on the resistance and transmittance of the AZO thin films are discussed. The result shows that the metallic interlayers effectively improve the electric resistance but reduce the optical transmittance of the AZO thin films. These phenomena become more obvious as the interlayer thickness increases. However, the AZO with an aluminum interlayer still behaves an acceptable transmittance. Moreover, mechanical tests indicate that the aluminum interlayer increases the hardness and modulus, and reduce the residual stress of the AZO thin films. In contrast, the silver and copper interlayers decrease the AZO's mechanical properties. Comparing to those without any interlayer, the results show that the best interlayer is the 6 nm thick aluminum film.

  8. Zinc in +III oxidation state

    NASA Astrophysics Data System (ADS)

    Samanta, Devleena; Jena, Puru

    2012-02-01

    The possibility of Group 12 elements, such as Zn, Cd, and Hg existing in an oxidation state of +III or higher has fascinated chemists for decades. Significant efforts have been made in the past to achieve higher oxidation states for the heavier congener mercury (since the 3^rd ionization potential of the elements decrease as we go down the periodic table). It took nearly 20 years before experiment could confirm the theoretical prediction that Hg indeed can exist in an oxidation state of +IV. While this unusual property of Hg is attributed to the relativistic effects, Zn being much lighter than Hg has not been expected to have an oxidation state higher than +II. Using density functional theory we show that an oxidation state of +III for Zn can be realized by choosing specific ligands with large electron affinities i.e. superhalogens. We demonstrate this by a systematic study of the interaction of Zn with F, BO2, and AuF6 ligands whose electron affinities are progressively higher, namely, 3.4 eV, 4.4 eV, and 8.4 eV, respectively. Discovery of higher oxidation states of elements can help in the formulation of new reactions and hence in the development of new chemistry.

  9. Correlation of Zinc with Oxidative Stress Biomarkers

    PubMed Central

    Morales-Suárez-Varela, María; Llopis-González, Agustín; González-Albert, Verónica; López-Izquierdo, Raúl; González-Manzano, Isabel; Cháves, Javier; Huerta-Biosca, Vicente; Martin-Escudero, Juan C.

    2015-01-01

    Hypertension and smoking are related with oxidative stress (OS), which in turn reports on cellular aging. Zinc is an essential element involved in an individual’s physiology. The aim of this study was to evaluate the relation of zinc levels in serum and urine with OS and cellular aging and its effect on the development of hypertension. In a Spanish sample with 1500 individuals, subjects aged 20–59 years were selected, whose zinc intake levels fell within the recommended limits. These individuals were classified according to their smoking habits and hypertensive condition. A positive correlation was found (Pearson’s C = 0.639; p = 0.01) between Zn serum/urine quotient and oxidized glutathione levels (GSSG). Finally, risk of hypertension significantly increased when the GSSG levels exceeded the 75 percentile; OR = 2.80 (95%CI = 1.09–7.18) and AOR = 3.06 (95%CI = 0.96–9.71). Low zinc levels in serum were related with OS and cellular aging and were, in turn, to be a risk factor for hypertension.  PMID:25774936

  10. Formation of zinc oxide films using submicron zinc particle dispersions

    SciTech Connect

    Rajachidambaram, Meena Suhanya; Varga, Tamas; Kovarik, Libor; Sanghavi, Rahul P.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Han, Seungyeol; Chang, Chih-hung; Herman, Gregory S.

    2012-07-27

    The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x-ray diffraction and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes were observed for films annealed to 400 °C or higher, where nanoflakes, nanoribbons, nanoneedles and nanorods were formed as a result of stress induced fractures arising in the ZnO outer shell due to differential thermal expansion between the metallic Zn core and the ZnO shell. Mass transport occurs through these defects due to the high vapor pressure for metallic Zn at temperatures above 230 °C, whereupon the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. The Zn particles were also incorporated into zinc indium oxide precursor solutions to form thin film transistor test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing.

  11. Network array of zinc oxide whiskers

    NASA Astrophysics Data System (ADS)

    Xu, C. X.; Sun, X. W.; Chen, B. J.; Dong, Z. L.; Yu, M. B.; Zhang, X. H.; Chua, S. J.

    2005-01-01

    A zinc oxide (ZnO) whisker network array with sixfold symmetry was fabricated on ZnO-buffered (0001) sapphire substrate by the vapour-phase transport method using a mixture of zinc oxide and graphite powders as source materials and patterned gold as catalyst. From the ZnO buffer layer, hexagonal ZnO nanorods with identical in-plane structure grew epitaxially along the [0001] orientation to form vertical stems. The branches grew horizontally from six side-surfaces of the vertical stem along [01\\bar {1}0] and other equivalent directions. Most whiskers were confined along the six preferential orientations and interconnected with each other to form a regular network structure. The growth mechanism is discussed.

  12. 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.

  13. Process for preparing zinc oxide-based sorbents

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2011-06-07

    The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  14. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    SciTech Connect

    Nian, Qiong; Cheng, Gary J.; Callahan, Michael; Bailey, John; Look, David; Efstathiadis, Harry

    2015-06-01

    Commercial production of transparent conducting oxide (TCO) polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC) of solution deposited aluminium-doped zinc oxide (AZO) nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm{sup 2} V{sup −1} s{sup −1} with corresponding electrical resistivity and sheet resistances as low as 1 × 10{sup −3} Ω cm and 75 Ω/sq, respectively. The high mobility also enabled a high transmittance (T) of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods.

  15. Highly transparent conductive electrode with ultra-low HAZE by grain boundary modification of aqueous solution fabricated alumina-doped zinc oxide nanocrystals

    NASA Astrophysics Data System (ADS)

    Nian, Qiong; Callahan, Michael; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-06-01

    Commercial production of transparent conducting oxide (TCO) polycrystalline films requires high electrical conductivity with minimal degradation in optical transparency. Aqueous solution deposited TCO films would reduce production costs of TCO films but suffer from low electrical mobility, which severely degrades both electrical conductivity and optical transparency in the visible spectrum. Here, we demonstrated that grain boundary modification by ultra-violet laser crystallization (UVLC) of solution deposited aluminium-doped zinc oxide (AZO) nanocrystals results in high Hall mobility, with a corresponding dramatic improvement in AZO electrical conductance. The AZO films after laser irradiation exhibit electrical mobility up to 18.1 cm2 V-1 s-1 with corresponding electrical resistivity and sheet resistances as low as 1 × 10-3 Ω cm and 75 Ω/sq, respectively. The high mobility also enabled a high transmittance (T) of 88%-96% at 550 nm for the UVLC films. In addition, HAZE measurement shows AZO film scattering transmittance as low as 1.8%, which is superior over most other solution deposited transparent electrode alternatives such as silver nanowires. Thus, AZO films produced by the UVLC technique have a combined figure of merit for electrical conductivity, optical transparency, and optical HAZE higher than other solution based deposition techniques and comparable to vacuumed based deposition methods.

  16. Copper, silver, gold and zinc, cadmium, mercury oxides and hydroxides

    SciTech Connect

    Dirkse, T.P.

    1986-01-01

    This book provides a compilation of solubility data published up to 1984, including evaluations of the data. Data are presented on the following: copper (I) oxide; copper (II) oxide and hydroxide; silver (I) oxide; silver (II) oxide; gold (III) hydroxide; zinc oxide and hydroxide; cadmium oxide and hydroxide; and mercury (II) oxide.

  17. 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.

  18. Characterization of molybdenum doped indium oxide/aluminum doped zinc oxide thin film stacks for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Elamurugu, Elangovan; Flores, Raquel; Janeiro, Ricardo; Dahlem, Marcus; Viegas, Jaime

    2014-03-01

    Multilayer (ML) thin films, based on indium molybdenum oxide (IMO) and aluminum zinc oxide (AZO), having different stacking were deposited using RF sputtering at room temperature (RT). The total-layer thickness of the MLs ranges between 93 nm and 98 nm. The deposited films were characterized by their structural, electrical, microstructural, and optical properties. X-ray diffraction (XRD) peaks obtained at 2θ of around 30.6° and 34.27° are matched with cubic-In2O3 (222) and hexagonal-ZnO (002), respectively. The MLs have both nano-crystalline and polycrystalline structures depending on the layer properties. A conspicuous feature of XRD analysis is the absence of diffraction peak from 50 nm thick IMO layer when it is stacked below 50 nm thick AZO, whereas it appears significantly when the stacking is reversed to place IMO above AZO layer. Hall measurements confirmed that the deposited MLs are n- type conducting and the electrical properties are varied as a function of layer properties. The deposited MLs show high shortwavelength infrared transmittance (SWIRT) even at 3300 nm, which is ranging as high as 75 % - 90 %. Overall, the MLs show high transmittance in the entire Vis-SWIR region. The optical band gap (Eg) calculated using the absorption coefficient (α) and photon energy (hν) of the deposited MLs is ranging between 3.19 eV and 3.56 eV, depending on the layer properties. Selected as- deposited films were annealed in open air at 400 °C for 1 h; the transmittance of annealed films was improved but their electrical properties deteriorated. Atomic force microscopy (AFM) analysis shows that the root-mean-square (RMS) roughness of the MLs ranges between 0.8 nm and 1.5 nm.

  19. Electro-oxidation of two reactive azo dyes on boron-doped diamond electrode.

    PubMed

    Almomani, Fares; Baranova, Elena A

    2012-01-01

    Electrochemical oxidation (decolorization/degradation) of blue and red commercial reactive azo dyes was carried out on boron-doped diamond (BDD) electrode. The effect of various quantities of FeSO(4) was investigated in the electro-Fenton reaction on BDD. Progress of dyes degradation during the electrolysis and electro-Fenton reaction was monitored by UV-visible absorption and by estimation of the chemical oxygen demand (COD). Direct electrolysis showed a limiting capacity for red and blue dye removal even at high current densities, e.g. maximum red color and COD removal were 70 and 20%, respectively at 30 mA cm(-2) after 300 min. Higher red and blue color removal efficiencies were achieved by electro-Fenton oxidation. Current density of 30 mA cm(-2) in the presence of 0.05 mmol/L of FeSO(4) resulted in the red color and COD removal of 98 and 96%, respectively. The optimum FeSO(4) concentration for the electro-Fenton reaction was determined to be 0.05 mmol/L. Instantaneous current efficiency (ICE) in the presence of FeSO(4) was almost three times higher than for experiments carried out without FeSO(4). PMID:22744674

  20. Electro-oxidation of two reactive azo dyes on boron-doped diamond electrode.

    PubMed

    Almomani, Fares; Baranova, Elena A

    2012-01-01

    Electrochemical oxidation (decolorization/degradation) of blue and red commercial reactive azo dyes was carried out on boron-doped diamond (BDD) electrode. The effect of various quantities of FeSO(4) was investigated in the electro-Fenton reaction on BDD. Progress of dyes degradation during the electrolysis and electro-Fenton reaction was monitored by UV-visible absorption and by estimation of the chemical oxygen demand (COD). Direct electrolysis showed a limiting capacity for red and blue dye removal even at high current densities, e.g. maximum red color and COD removal were 70 and 20%, respectively at 30 mA cm(-2) after 300 min. Higher red and blue color removal efficiencies were achieved by electro-Fenton oxidation. Current density of 30 mA cm(-2) in the presence of 0.05 mmol/L of FeSO(4) resulted in the red color and COD removal of 98 and 96%, respectively. The optimum FeSO(4) concentration for the electro-Fenton reaction was determined to be 0.05 mmol/L. Instantaneous current efficiency (ICE) in the presence of FeSO(4) was almost three times higher than for experiments carried out without FeSO(4).

  1. Plasmonic Three-Dimensional Transparent Conductor Based on Al-Doped Zinc Oxide-Coated Nanostructured Glass Using Atomic Layer Deposition

    SciTech Connect

    Malek, Gary A.; Aytug, Tolga; Liu, Qingfeng; Wu, Judy

    2015-04-02

    Transparent nanostructured glass coatings, fabricated on glass substrates, with a unique three-dimensional (3D) architecture were utilized as the foundation for the design of plasmonic 3D transparent conductors. Transformation of the non-conducting 3D structure to a conducting 3D network was accomplished through atomic layer deposition of aluminum-doped zinc oxide (AZO). After AZO growth, gold nanoparticles (AuNPs) were deposited by electronbeam evaporation to enhance light trapping and decrease the overall sheet resistance. Field emission scanning electron microscopy and atomic force microcopy images revealed the highly porous, nanostructured morphology of the AZO coated glass surface along with the in-plane dimensions of the deposited AuNPs. Sheet resistance measurements conducted on the coated samples verified that the electrical properties of the 3D network are comparable to that of the untextured two-dimensional AZO coated glass substrates. In addition, transmittance measurements of the glass samples coated with various AZO thicknesses showed preservation of the highly transparent nature of each sample, while the AuNPs demonstrated enhanced light scattering as well as light-trapping capability.

  2. Plasmonic Three-Dimensional Transparent Conductor Based on Al-Doped Zinc Oxide-Coated Nanostructured Glass Using Atomic Layer Deposition

    DOE PAGESBeta

    Malek, Gary A.; Aytug, Tolga; Liu, Qingfeng; Wu, Judy

    2015-04-02

    Transparent nanostructured glass coatings, fabricated on glass substrates, with a unique three-dimensional (3D) architecture were utilized as the foundation for the design of plasmonic 3D transparent conductors. Transformation of the non-conducting 3D structure to a conducting 3D network was accomplished through atomic layer deposition of aluminum-doped zinc oxide (AZO). After AZO growth, gold nanoparticles (AuNPs) were deposited by electronbeam evaporation to enhance light trapping and decrease the overall sheet resistance. Field emission scanning electron microscopy and atomic force microcopy images revealed the highly porous, nanostructured morphology of the AZO coated glass surface along with the in-plane dimensions of the depositedmore » AuNPs. Sheet resistance measurements conducted on the coated samples verified that the electrical properties of the 3D network are comparable to that of the untextured two-dimensional AZO coated glass substrates. In addition, transmittance measurements of the glass samples coated with various AZO thicknesses showed preservation of the highly transparent nature of each sample, while the AuNPs demonstrated enhanced light scattering as well as light-trapping capability.« less

  3. 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.

  4. Plasmonic three-dimensional transparent conductor based on Al-doped zinc oxide-coated nanostructured glass using atomic layer deposition.

    PubMed

    Malek, Gary A; Aytug, Tolga; Liu, Qingfeng; Wu, Judy

    2015-04-29

    Transparent nanostructured glass coatings, fabricated on glass substrates, with a unique three-dimensional (3D) architecture were utilized as the foundation for designing plasmonic 3D transparent conductors. Transformation of the nonconducting 3D structure to a conducting porous surface network was accomplished through atomic layer deposition of aluminum-doped zinc oxide (AZO). After AZO growth, gold nanoparticles (AuNPs) were deposited by electron-beam evaporation to enhance light trapping and decrease the overall sheet resistance. Field emission scanning electron microscopy and atomic force microcopy images revealed the highly porous, nanostructured morphology of the AZO-coated glass surface along with the in-plane dimensions of the deposited AuNPs. Sheet resistance measurements conducted on the coated samples verified that the electrical properties of the 3D network are comparable to those of untextured two-dimensional AZO-coated glass substrates. In addition, transmittance measurements of the glass samples coated at various AZO thicknesses showed preservation of the transparent nature of each sample, and the AuNPs demonstrated enhanced light scattering as well as light-trapping capabilities.

  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. PMID:27483888

  6. Plasmonic three-dimensional transparent conductor based on Al-doped zinc oxide-coated nanostructured glass using atomic layer deposition.

    PubMed

    Malek, Gary A; Aytug, Tolga; Liu, Qingfeng; Wu, Judy

    2015-04-29

    Transparent nanostructured glass coatings, fabricated on glass substrates, with a unique three-dimensional (3D) architecture were utilized as the foundation for designing plasmonic 3D transparent conductors. Transformation of the nonconducting 3D structure to a conducting porous surface network was accomplished through atomic layer deposition of aluminum-doped zinc oxide (AZO). After AZO growth, gold nanoparticles (AuNPs) were deposited by electron-beam evaporation to enhance light trapping and decrease the overall sheet resistance. Field emission scanning electron microscopy and atomic force microcopy images revealed the highly porous, nanostructured morphology of the AZO-coated glass surface along with the in-plane dimensions of the deposited AuNPs. Sheet resistance measurements conducted on the coated samples verified that the electrical properties of the 3D network are comparable to those of untextured two-dimensional AZO-coated glass substrates. In addition, transmittance measurements of the glass samples coated at various AZO thicknesses showed preservation of the transparent nature of each sample, and the AuNPs demonstrated enhanced light scattering as well as light-trapping capabilities. PMID:25835062

  7. Recent developments in zinc oxide target chemistry

    SciTech Connect

    Heaton, R.C.; Taylor, W.A.; Phillips, D.R.; Jamriska, D.J. Sr.; Garcia, J.B.

    1994-04-01

    Zinc oxide targets irradiated with high energy protons at the Los Alamos Meson Physics Facility (LAMPF) contain a number of radioactive spallation products in quantities large enough to warrant recovery. This paper describes methods for recovering {sup 7}Be, {sup 46}Sc, and {sup 48}V from such targets and offers suggestions on possible ways to recover additional isotopes. The proposed methods are based on traditional precipitation and ion exchange techniques, are readily adaptable to hot cell use, and produce no hazardous waste components. The products are obtained in moderate to high yields and have excellent radiopurity.

  8. Varistor action in zinc oxide suspension

    NASA Astrophysics Data System (ADS)

    Negita, K.; Yamaguchi, T.; Tsuchie, T.; Shigematsu, N.

    2003-04-01

    In a suspension composed of zinc oxide (ZnO) particles and silicone oil, it is found that the current density dramatically increases above a specific electric field (break down field Eb). In ac measurement, the nonlinear coefficient (α), which characterizes the relationship between current density J and the electric field E as J∝Eα, changes from ˜1 to ˜30 when increasing the electric field through Eb. On the basis of the α value, temperature dependence of Eb, etc., the mechanism of the fluid varistor is briefly discussed.

  9. 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

  10. 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.

  11. 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

  12. Zinc oxide doped graphene oxide films for gas sensing applications

    NASA Astrophysics Data System (ADS)

    Chetna, Kumar, Shani; Garg, A.; Chowdhuri, A.; Dhingra, V.; Chaudhary, S.; Kapoor, A.

    2016-05-01

    Graphene Oxide (GO) is analogous to graphene, but presence of many functional groups makes its physical and chemical properties essentially different from those of graphene. GO is found to be a promising material for low cost fabrication of highly versatile and environment friendly gas sensors. Selectivity, reversibility and sensitivity of GO based gas sensor have been improved by hybridization with Zinc Oxide nanoparticles. The device is fabricated by spin coating of deionized water dispersed GO flakes (synthesized using traditional hummer's method) doped with Zinc Oxide on standard glass substrate. Since GO is an insulator and functional groups on GO nanosheets play vital role in adsorbing gas molecules, it is being used as an adsorber. Additionally, on being exposed to certain gases the electric and optical characteristics of GO material exhibit an alteration in behavior. For the conductivity, we use Zinc Oxide, as it displays a high sensitivity towards conduction. The effects of the compositions, structural defects and morphologies of graphene based sensing layers and the configurations of sensing devices on the performances of gas sensors were investigated by Raman Spectroscopy, X-ray diffraction(XRD) and Keithley Sourcemeter.

  13. Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts.

    PubMed

    Chen, Xuxing; Li, Yunpeng; Pan, Xiaoyang; Cortie, David; Huang, Xintang; Yi, Zhiguo

    2016-01-01

    The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths <400 nm and over 0.1% at wavelengths ∼470 nm achieved on the silver decorated zinc oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation. PMID:27435112

  14. Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts

    PubMed Central

    Chen, Xuxing; Li, Yunpeng; Pan, Xiaoyang; Cortie, David; Huang, Xintang; Yi, Zhiguo

    2016-01-01

    The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths <400 nm and over 0.1% at wavelengths ∼470 nm achieved on the silver decorated zinc oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation. PMID:27435112

  15. Zinc Oxide Nanomaterials for Biomedical Fluorescence Detection

    PubMed Central

    Hahm, Jong-in

    2014-01-01

    One-dimensional zinc oxide nanomaterials have been recently developed into novel, extremely effective, optical signal-enhancing bioplatforms. Their usefulness has been demonstrated in various biomedical fluorescence assays. Fluorescence is extensively used in biology and medicine as a sensitive and noninvasive detection method for tracking and analyzing biological molecules. Achieving high sensitivity via improving signal-to-noise ratio is of paramount importance in fluorescence-based, trace-level detection. Recent advances in the development of optically superior one-dimensional materials have contributed to this important biomedical area of detection. This review article will discuss major research developments that have so far been made in this emerging and exciting topical field. The discussion will cover a broad range of subjects including synthesis of zinc oxide nanorods (ZnO NRs), various properties differentiating them as suitable optical biodetection platforms, their demonstrated applicability in DNA and protein detection, and the nanomaterial characteristics relevant for biomolecular fluorescence enhancement. This review will then summarize the current status of ZnO NR-based biodetection and further elaborate future utility of ZnO NR platforms for advanced biomedical assays, based on their proven advantages. Lastly, present challenges experienced in this topical area will be identified and focal subject areas for future research will be suggested as well. PMID:24730276

  16. 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].

  17. Kinetic study of electro-Fenton oxidation of azo dyes on boron-doped diamond electrode.

    PubMed

    Almomani, Fares; Baranova, Elena A

    2013-01-01

    The present work compares electrochemical degradation of red and blue azo textile dyes in single- and two-compartment electrochemical cells in the presence of Fenton reagent (Fe2+) and using a boron-doped diamond anode. Degradation of both dyes was related to the concentration of dye, applied current density and the concentration of FeSO4 catalyst. Complete colour removal and approximately 91% of organic matter oxidation was achieved in a two-compartment electrochemical cell at an applied current density of 20 mA x cm(-2), pH of 3 and Fe(2+) ion concentration of 0.02 mM. Higher current density and reaction time were required to achieve the same removals in a one-compartment electrochemical cell. Dye degradation kinetics as well as chemical oxygen demand removal rate were successfully modelled to pseudo first-order kinetics. The apparent first-order rate constants (k(o)) for degradation of red dye with an initial concentration of 20, 40 and 60 ppm were found to be 2.67 +/- 0.16, 2.19 +/- 0.09 and 1.5 +/- 0.03 min(-1), and for blue dye at the same initial concentrations were 1.99 +/- 0.2, 0.95 +/- 0.02 and 0.71 +/- 0.030 min(-1), respectively. PMID:24191481

  18. Catalytic wet peroxide oxidation of azo dye (Congo red) using modified Y zeolite as catalyst.

    PubMed

    Kondru, Arun Kumar; Kumar, Pradeep; Chand, Shri

    2009-07-15

    The present study explores the degradation of azo dye (Congo red) by catalytic wet peroxide oxidation using Fe exchanged commercial Y zeolite as a catalyst. The effects of various operating parameters like temperature, initial pH, hydrogen peroxide concentration and catalyst loading on the removal of dye, color and COD from an aqueous solution were studied at atmospheric pressure. The percent removals of dye, color and COD at optimum pH(0) 7, 90 degrees C using 0.6 ml H(2)O(2)/350 ml solution and 1g/l catalyst was 97% (in 4h), 100% (in 45 min) and 58% (in 4h), respectively. The % dye removal has been found to be less in comparison to % color removal at all conditions, e.g. dye removal in 45 min and at above conditions was 82%, whereas the color removal was 100%. The results indicate that the Fe exchanged Y zeolite is a promising catalyst for dye removal. Fe exchanged catalyst is characterized using XRD, SEM/EDAX, surface area analyzer and FTIR. Though the dye, color and COD removals were maximum at pH(0) 2 but as the leaching of Fe from the catalyst was more in acidic pH range, pH(0) 7 was taken as operating pH due to almost comparable removals as of pH(0) 2 and no leaching of Fe ions. PMID:19135790

  19. Kinetic study of electro-Fenton oxidation of azo dyes on boron-doped diamond electrode.

    PubMed

    Almomani, Fares; Baranova, Elena A

    2013-01-01

    The present work compares electrochemical degradation of red and blue azo textile dyes in single- and two-compartment electrochemical cells in the presence of Fenton reagent (Fe2+) and using a boron-doped diamond anode. Degradation of both dyes was related to the concentration of dye, applied current density and the concentration of FeSO4 catalyst. Complete colour removal and approximately 91% of organic matter oxidation was achieved in a two-compartment electrochemical cell at an applied current density of 20 mA x cm(-2), pH of 3 and Fe(2+) ion concentration of 0.02 mM. Higher current density and reaction time were required to achieve the same removals in a one-compartment electrochemical cell. Dye degradation kinetics as well as chemical oxygen demand removal rate were successfully modelled to pseudo first-order kinetics. The apparent first-order rate constants (k(o)) for degradation of red dye with an initial concentration of 20, 40 and 60 ppm were found to be 2.67 +/- 0.16, 2.19 +/- 0.09 and 1.5 +/- 0.03 min(-1), and for blue dye at the same initial concentrations were 1.99 +/- 0.2, 0.95 +/- 0.02 and 0.71 +/- 0.030 min(-1), respectively.

  20. 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

  1. Relative Penetration of Zinc Oxide and Zinc Ions into Human Skin after Application of Different Zinc Oxide Formulations.

    PubMed

    Holmes, Amy M; Song, Zhen; Moghimi, Hamid R; Roberts, Michael S

    2016-02-23

    Zinc oxide (ZnO) is frequently used in commercial sunscreen formulations to deliver their broad range of UV protection properties. Concern has been raised about the extent to which these ZnO particles (both micronized and nanoparticulate) penetrate the skin and their resultant toxicity. This work has explored the human epidermal skin penetration of zinc oxide and its labile zinc ion dissolution product that may potentially be formed after application of ZnO nanoparticles to human epidermis. Three ZnO nanoparticle formulations were used: a suspension in the oil, capric caprylic triglycerides (CCT), the base formulation commonly used in commercially available sunscreen products; an aqueous ZnO suspension at pH 6, similar to the natural skin surface pH; and an aqueous ZnO suspension at pH 9, a pH at which ZnO is stable and there is minimal pH-induced impairment of epidermal integrity. In each case, the ZnO in the formulations did not penetrate into the intact viable epidermis for any of the formulations but was associated with an enhanced increase in zinc ion fluorescence signal in both the stratum corneum and the viable epidermis. The highest labile zinc fluorescence was found for the ZnO suspension at pH 6. It is concluded that, while topically applied ZnO does not penetrate into the viable epidermis, these applications are associated with hydrolysis of ZnO on the skin surface, leading to an increase in zinc ion levels in the stratum corneum, thence in the viable epidermis and subsequently in the systemic circulation and the urine.

  2. 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.

  3. 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

  4. Degradation process analysis of the azo dyes by catalytic wet air oxidation with catalyst CuO/γ-Al2O3.

    PubMed

    Hua, Li; Ma, Hongrui; Zhang, Lei

    2013-01-01

    Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide. PMID:22795071

  5. Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K.

    2013-10-01

    We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (Ts). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10-3 Ω cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at Ts of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein-Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ˜110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

  6. Photocatalytic paper using zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M.; Dutta, Joydeep

    2010-10-01

    Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm-2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions.

  7. Zinc oxide thin film acoustic sensor

    SciTech Connect

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah; Mansour, Hazim Louis

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  8. 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.

  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. Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom

    ERIC Educational Resources Information Center

    Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

    2014-01-01

    In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

  11. Influence of phytase, EDTA, and polyphenols on zinc absorption in adults from porridges fortified with zinc sulfate or zinc oxide.

    PubMed

    Brnić, Marica; Wegmüller, Rita; Zeder, Christophe; Senti, Gabriela; Hurrell, Richard F

    2014-09-01

    Fortification of cereal staples with zinc is recommended to combat zinc deficiency. To optimize zinc absorption, strategies are needed to overcome the inhibitory effect of phytic acid (PA) and perhaps polyphenols. Five zinc absorption studies were conducted in young adults consuming maize or sorghum porridges fortified with 2 mg zinc as zinc sulfate (ZnSO4) or zinc oxide (ZnO) and containing combinations of PA or polyphenols as potential inhibitors and EDTA and phytase as potential enhancers. Fractional absorption of zinc (FAZ) was measured by using the double isotopic tracer ratio method. Adding phytase to the maize porridge immediately before consumption or using phytase for dephytinization during meal preparation both increased FAZ by >80% (both P < 0.001). Adding Na2EDTA at an EDTA:zinc molar ratio of 1:1 increased FAZ from maize porridge fortified with ZnSO4 by 30% (P = 0.01) but had no influence at higher EDTA ratios or on absorption from ZnO. FAZ was slightly higher from ZnSO4 than from ZnO (P = 0.02). Sorghum polyphenols had no effect on FAZ from dephytinized sorghum porridges but decreased FAZ by 20% from PA-rich sorghum porridges (P < 0.02). The combined inhibitory effect of polyphenols and PA was overcome by EDTA. In conclusion, ZnSO4 was better absorbed than ZnO, phytase used to degrade PA during digestion or during food preparation substantially increased zinc absorption from zinc-fortified cereals, EDTA at a 1:1 molar ratio modestly enhanced zinc absorption from ZnSO4-fortified cereals but not ZnO-fortified cereals, and sorghum polyphenols inhibited zinc absorption in the presence, but not absence, of PA. This trial was registered at clinicaltrials.gov as NCT01210794.

  12. Toxicokinetics of zinc oxide nanoparticles in rats

    NASA Astrophysics Data System (ADS)

    Chung, H. E.; Yu, J.; Baek, M.; Lee, J. A.; Kim, M. S.; Kim, S. H.; Maeng, E. H.; Lee, J. K.; Jeong, J.; Choi, S. J.

    2013-04-01

    Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

  13. Bioavailability of zinc in Wistar rats fed with rice fortified with zinc oxide.

    PubMed

    Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Sant'Ana, Helena Maria Pinheiro

    2014-06-01

    The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification.

  14. Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide

    PubMed Central

    Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

    2014-01-01

    The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

  15. Nanocrystalline semiconductor doped rare earth oxide for the photocatalytic degradation studies on Acid Blue 113: A di-azo compound under UV slurry photoreactor.

    PubMed

    Suganya Josephine, G A; Mary Nisha, U; Meenakshi, G; Sivasamy, A

    2015-11-01

    Preventive measures for the control of environmental pollution and its remediation has received much interest in recent years due to the world-wide increase in the contamination of water bodies. Contributions of these harmful effluents are caused by the leather processing, pharmaceutical, cosmetic, textile, agricultural and other chemical industries. Nowadays, advanced oxidation processes considered to be better option for the complete destruction of organic contaminants in water and wastewater. Acid Blue 113 is a most widely used di-azo compound in leather, textile, dying and food industry as a color rending compound. In the present study, we have reported the photo catalytic degradation of Acid Blue 113 using a nanocrystalline semiconductor doped rare earth oxide as a photo catalyst under UV light irradiation. The photocatalyst was prepared by a simple precipitation technique and were characterized by XRD, FT-IR, UV-DRS and FE-SEM analysis. The experimental results proved that the prepared photo catalyst was nanocrystalline and highly active in the UV region. The UV-DRS results showed the band gap energy was 3.15eV for the prepared photo catalyst. The photodegradation efficiency was analyzed by various experimental parameters such as pH, catalyst dosage, variation of substrate concentration and effect of electrolyte addition. The photo degradation process followed a pseudo first order kinetics and was continuously monitored by UV-visible spectrophotometer. The experimental results proved the efficacy of the nanocrystalline zinc oxide doped dysprosium oxide which are highly active under UV light irradiations. It is also suggested that the prepared material would find wider applications in environmental remediation technologies to remove the carcinogenic and toxic moieties present in the industrial effluents.

  16. Nanocrystalline semiconductor doped rare earth oxide for the photocatalytic degradation studies on Acid Blue 113: A di-azo compound under UV slurry photoreactor.

    PubMed

    Suganya Josephine, G A; Mary Nisha, U; Meenakshi, G; Sivasamy, A

    2015-11-01

    Preventive measures for the control of environmental pollution and its remediation has received much interest in recent years due to the world-wide increase in the contamination of water bodies. Contributions of these harmful effluents are caused by the leather processing, pharmaceutical, cosmetic, textile, agricultural and other chemical industries. Nowadays, advanced oxidation processes considered to be better option for the complete destruction of organic contaminants in water and wastewater. Acid Blue 113 is a most widely used di-azo compound in leather, textile, dying and food industry as a color rending compound. In the present study, we have reported the photo catalytic degradation of Acid Blue 113 using a nanocrystalline semiconductor doped rare earth oxide as a photo catalyst under UV light irradiation. The photocatalyst was prepared by a simple precipitation technique and were characterized by XRD, FT-IR, UV-DRS and FE-SEM analysis. The experimental results proved that the prepared photo catalyst was nanocrystalline and highly active in the UV region. The UV-DRS results showed the band gap energy was 3.15eV for the prepared photo catalyst. The photodegradation efficiency was analyzed by various experimental parameters such as pH, catalyst dosage, variation of substrate concentration and effect of electrolyte addition. The photo degradation process followed a pseudo first order kinetics and was continuously monitored by UV-visible spectrophotometer. The experimental results proved the efficacy of the nanocrystalline zinc oxide doped dysprosium oxide which are highly active under UV light irradiations. It is also suggested that the prepared material would find wider applications in environmental remediation technologies to remove the carcinogenic and toxic moieties present in the industrial effluents. PMID:26025644

  17. Copper(II)-catalyzed room temperature aerobic oxidation of hydroxamic acids and hydrazides to acyl-nitroso and azo intermediates, and their Diels-Alder trapping.

    PubMed

    Chaiyaveij, Duangduan; Cleary, Leah; Batsanov, Andrei S; Marder, Todd B; Shea, Kenneth J; Whiting, Andrew

    2011-07-01

    CuCl(2), in the presence of a 2-ethyl-2-oxazoline ligand, is an effective catalyst for the room temperature, aerobic oxidation of hydroxamic acids and hydrazides, to acyl-nitroso and azo dienophiles respectively, which are efficiently trapped in situ via both inter- and intramolecular hetero-Diels-Alder reactions with dienes. Both inter- and intramolecular variants of the Diels-Alder reaction are suitable under the reaction conditions using a variety of solvents. Under the same conditions, an acyl hydrazide was also oxidized to give an acyl-azo dienophile which was trapped intramolecularly by a diene. PMID:21644530

  18. The kinetic of photoreactions in zinc oxide microrods

    NASA Astrophysics Data System (ADS)

    Fiedot, M.; Rac, O.; Suchorska-Woźniak, P.; Nawrot, W.; Teterycz, H.

    2016-01-01

    Zinc oxide is the oldest sensing material used in the chemical resistive gas sensors which allow to detect many gases, such as carbon oxide, nitrogen oxides and other. This material is also widely used in medicine and daily life as antibacterial agent. For this reason this semiconductor is often synthesized on the polymer substrates such as foils and textiles. In presented results zinc oxide was deposited on the surface of poly(ethylene terephthalate) foil to obtain antibacterial material. As synthesis method chemical bath deposition was chosen. The growth of zinc oxide structures was carried out in water solution of zinc nitrate (V) and hexamethylenetetramine in 90°C during 9 h. Because antibacterial properties of ZnO are strongly depended on photocatalytic and electric properties of this semiconductor impedance spectroscopy measurements were carried out. During the measurements material was tested with and without UV light to determinate the kinetic of photoreactions in zinc oxide. Moreover the composite was analyzed by XRD diffraction and scanning electron microscope. The X-ray analysis indicated that obtained material has the structure of wurtzite which is typical of zinc oxide. SEM images showed that on the PET foil microrods of ZnO were formed. The impedance spectroscopy measurements of ZnO layer showed that in UV light significant changes in the conductivity of the material are observed.

  19. Zinc oxide nanoflowers make new blood vessels

    NASA Astrophysics Data System (ADS)

    Barui, Ayan Kumar; Veeriah, Vimal; Mukherjee, Sudip; Manna, Joydeb; Patel, Ajay Kumar; Patra, Sujata; Pal, Krishnendu; Murali, Shruthi; Rana, Rohit K.; Chatterjee, Suvro; Patra, Chitta Ranjan

    2012-11-01

    It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role.It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood

  20. Nonstoichiometric zinc oxide and indium-doped zinc oxide: Electrical conductivity and {sup 111}In-TDPAC studies

    SciTech Connect

    Wang, R.; Sleight, A.W.; Platzer, R.; Gardner, J.A.

    1996-02-15

    Indium-doped zinc oxide powders have been prepared which show room-temperature electrical conductivities as high as 30 {Omega}{sup {minus}1} cm{sup {minus}1}. The indium doping apparently occurs as Zn{sub 1-x}In{sub x}O,Zn{sub 1-y}In{sub y}O{sub 1+y/2}, or a combination of these. Optimum conductivity occurs for Zn{sub 1-x}In{sub x}O where the maximum value of x obtained was about 0.5 at%. The degrees of sample reduction were determined by iodimetric titration. Time differential perturbed angular correlation (TDPAC) spectroscopy on indium doped zinc oxide is consistent with indium substituting at normal zinc sites in the ZnO lattice. TDPAC studies on zinc oxide annealed under zinc vapors show a second environment for the {sup 111}In probe. In this case, there is an unusually high temperature dependence of the electric field gradient which may be caused by a nearby zinc interstitial. An important conclusion of this work is that zinc interstitials are not ionized and do not therefore contribute significantly to the increased conductivity of reduced zinc oxide.

  1. Acetone sensor based on zinc oxide hexagonal tubes

    SciTech Connect

    Hastir, Anita Singh, Onkar Anand, Kanika Singh, Ravi Chand

    2014-04-24

    In this work hexagonal tubes of zinc oxide have been synthesized by co-precipitation method. For structural, morphological, elemental and optical analysis synthesized powders were characterized by using x-ray diffraction, field emission scanning microscope, EDX, UV-visible and FTIR techniques. For acetone sensing thick films of zinc oxide have been deposited on alumina substrate. The fabricated sensors exhibited maximum sensing response towards acetone vapour at an optimum operating temperature of 400°C.

  2. Labyrinth patterns of zinc oxide on porous silicon substrate

    NASA Astrophysics Data System (ADS)

    Martínez, L.; Kumar, Y.; Mayorga, D.; Goswami, N.; Agarwal, V.

    2014-03-01

    The substrate treatment dependent formation of different micro-morphologies of zinc oxide over PS substrate has been reported. Effect of substrate oxidation and annealing has been studied. Changes in the structural properties were seen in the form of labyrinth patterns developed on the surface and were studied with the help of scanning electron microscope (SEM), atomic force microscope (AFM). X-ray diffraction (XRD) along with UV-visible absorption and photoluminescence (PL) spectroscopy were performed for characterizing the zinc oxide film and the hybrid structure. A relatively flat film of nanostructured zinc oxide particles is found to form on the oxidized substrate as compared to the nanostructured labyrinth patterns formed on the un-oxidized substrate with enhanced aspect ratio. Such micromorphologies can be very promising for fabricating highly sensitive gas sensors.

  3. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    PubMed

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications.

  4. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    PubMed

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. PMID:26453887

  5. Ultrasound assisted additive free synthesis of nanocrystalline zinc oxide.

    PubMed

    Bhatte, Kushal D; Fujita, Shin-Ichiro; Arai, Masahiko; Pandit, Anirudha B; Bhanage, Bhalchandra M

    2011-01-01

    A novel method for the synthesis of nanocrystalline zinc oxide without any additive was developed using zinc acetate and 1,4-butanediol through sonication. The structure and morphology of prepared nanocrystalline zinc oxide was investigated by various techniques like TEM, XRD, EDAX, UV-Vis spectroscopy. The solvent 1,4-butanediol played a dual role of fuel as well as capping agent eliminating addition of any extraneous species. The results showed that using ultrasound sonication is green, cost effective compared to conventional wet chemical method for ZnO nanoparticle synthesis. PMID:20634118

  6. Zinc oxide nanostructures confined in porous silicas.

    PubMed

    Coasne, Benoit; Mezy, Aude; Pellenq, R J M; Ravot, D; Tedenac, J C

    2009-02-18

    We report on molecular simulations of zinc oxide nanostructures obtained within silica nanopores of diameter D = 1.6 nm and D = 3.2 nm. Both the effects of confinement (by varying the pore size) and degree of pore filling on the structure of the nanomaterial are addressed. Two complementary approaches are adopted: 1) the stability of the three crystalline phases of ZnO (wurtzite, rocksalt, and blende) in the silica nanopores is studied, and 2) ZnO nanostructures are obtained by slowly cooling down a homogeneous liquid phase confined in the silica pores. None of the ideal nanostructures (wurtzite, rocksalt, blende) retains the ideal structure of the initial crystal when confined within the silica pores. Only the structure starting from the ideal wurtzite nanocrystal remains significantly crystalline after relaxation, as revealed by the marked peaks in the pair correlation functions for this system. The morphology and degree of cristallinity of the structures are found to depend on the parameters involved in the synthesis (pore size, filling density). Nanograin boundaries are observed between domains of different crystal structures. Reminiscent features of the bulk behavior, such as faceting of the nanostructures, are also observed when the system size becomes large. We show that the use of nanopores as a template imposes that the confined particles exhibit neutral (basal) surfaces. These predictions provide a guide to experiments on semiconductor nanoparticles.

  7. Biomedical Applications of Zinc Oxide Nanomaterials

    PubMed Central

    Zhang, Yin; Nayak, Tapas R.; Hong, Hao; Cai, Weibo

    2013-01-01

    Nanotechnology has witnessed tremendous advancement over the last several decades. Zinc oxide (ZnO), which can exhibit a wide variety of nanostructures, possesses unique semiconducting, optical, and piezoelectric properties hence has been investigated for a wide variety of applications. One of the most important features of ZnO nanomaterials is low toxicity and biodegradability. Zn2+ is an indispensable trace element for adults (~10 mg of Zn2+ per day is recommended) and it is involved in various aspects of metabolism. Chemically, the surface of ZnO is rich in -OH groups, which can be readily functionalized by various surface decorating molecules. In this review article, we summarized the current status of the use of ZnO nanomaterials for biomedical applications, such as biomedical imaging (which includes fluorescence, magnetic resonance, positron emission tomography, as well as dual-modality imaging), drug delivery, gene delivery, and biosensing of a wide array of molecules of interest. Research in biomedical applications of ZnO nanomaterials will continue to flourish over the next decade, and much research effort will be needed to develop biocompatible/biodegradable ZnO nanoplatforms for potential clinical translation. PMID:24206130

  8. Graphene oxide supported copper oxide nanoneedles: An efficient hybrid material for removal of toxic azo dyes

    NASA Astrophysics Data System (ADS)

    Rajesh, Rajendiran; Iyer, Sahithya S.; Ezhilan, Jayabal; Kumar, S. Senthil; Venkatesan, Rengarajan

    2016-09-01

    Herein, we report a simple, one step synthesis of hybrid copper oxide nanoneedles on graphene oxide sheets (GO-CuONNs) through sonochemical method. The present method affords a facile mean for controlling effective concentration of the active CuO nanoneedles on the graphene oxide sheets, and also offers the necessary stability to the resulting GO-CuONNs structure for adsorption transformations.Furthermore, this hybrid GO-CuONNs is successfully employed in the removal of a series of hazardous ionic organic dyes namely coomassie brilliant blue, methylene blue, congo red and amidoblack 10B. Through careful investigation of the material, we found that the synergetic effect between CuONNs and GO play a significant role in the adsorption of all the dyes studied. The prepared hybrid material contains both hydrophobic and hydrophilic environment which is expected to enhance the electrostatic interaction between the adsorbent and the dye molecules, consequently favouring the adsorption process.

  9. Graphene oxide supported copper oxide nanoneedles: An efficient hybrid material for removal of toxic azo dyes.

    PubMed

    Rajesh, Rajendiran; Iyer, Sahithya S; Ezhilan, Jayabal; Kumar, S Senthil; Venkatesan, Rengarajan

    2016-09-01

    Herein, we report a simple, one step synthesis of hybrid copper oxide nanoneedles on graphene oxide sheets (GO-CuONNs) through sonochemical method. The present method affords a facile mean for controlling effective concentration of the active CuO nanoneedles on the graphene oxide sheets, and also offers the necessary stability to the resulting GO-CuONNs structure for adsorption transformations.Furthermore, this hybrid GO-CuONNs is successfully employed in the removal of a series of hazardous ionic organic dyes namely coomassie brilliant blue, methylene blue, congo red and amidoblack 10B. Through careful investigation of the material, we found that the synergetic effect between CuONNs and GO play a significant role in the adsorption of all the dyes studied. The prepared hybrid material contains both hydrophobic and hydrophilic environment which is expected to enhance the electrostatic interaction between the adsorbent and the dye molecules, consequently favouring the adsorption process.

  10. Significant Enhancement in the Conductivity of Al-Doped Zinc Oxide thin Films for TCO Application

    NASA Astrophysics Data System (ADS)

    Mohite, R. M.; Ansari, J. N.; Roy, A. S.; Kothawale, R. R.

    2016-03-01

    Nanostructured Al-doped Zinc oxide (ZnO) thin films were deposited on glass substrate by chemical bath deposition (CBD) using aqueous zinc nitrate solution and subjected for different characterizations. Effect of Al3+ substitution on the properties of ZnO annealed at 400∘C was studied by XRD and UV-Vis for structural studies, SEM and TEM for surface morphology and DC four probe resistivity measurements for electrical properties. Al3+ substitution does not influence the morphology and well-known peaks related to wurtzite structure of ZnO. Electron microscopy (SEM and TEM) confirms rod shaped Al-doped ZnO nanocrystals with average width of 50nm. The optical band gap determined by UV-Visible spectroscopy was found to be in the range 3.37eV to 3.44eV. An EPR spectrum of AZO reveals peak at g=1.96 is due to shallow donors Zn interstitial. The DC electrical resistivity measurements of Al-doped ZnO show a minimum resistivity of 3.77×10-2Ω-cm. Therefore, these samples have potential use in n-type window layer in optoelectronic devices, organic solar cells, photonic crystals, photo-detectors, light emitting diodes (LEDs), gas sensors and chemical sensors.

  11. Genotoxic effects of zinc oxide nanoparticles.

    PubMed

    Heim, Julia; Felder, Eva; Tahir, Muhammad Nawaz; Kaltbeitzel, Anke; Heinrich, Ulf Ruediger; Brochhausen, Christoph; Mailänder, Volker; Tremel, Wolfgang; Brieger, Juergen

    2015-05-21

    The potential toxicity of nanoparticles has currently provoked public and scientific discussions, and attempts to develop generally accepted handling procedures for nanoparticles are under way. The investigation of the impact of nanoparticles on human health is overdue and reliable test systems accounting for the special properties of nanomaterials must be developed. Nanoparticular zinc oxide (ZnO) may be internalised through ambient air or the topical application of cosmetics, only to name a few, with unpredictable health effects. Therefore, we analysed the determinants of ZnO nanoparticle (NP) genotoxicity. ZnO NPs (15-18 nm in diameter) were investigated at concentrations of 0.1, 10 and 100 μg mL(-1) using the cell line A549. Internalised NPs were only infrequently detectable by TEM, but strongly increased Zn(2+) levels in the cytoplasm and even more in the nuclear fraction, as measured by atom absorption spectroscopy, indicative of an internalised zinc and nuclear accumulation. We observed a time and dosage dependent reduction of cellular viability after ZnO NP exposure. ZnCl2 exposure to cells induced similar impairments of cellular viability. Complexation of Zn(2+) with diethylene triamine pentaacetic acid (DTPA) resulted in the loss of toxicity of NPs, indicating the relevant role of Zn(2+) for ZnO NP toxicity. Foci analyses showed the induction of DNA double strand breaks (DSBs) by ZnO NPs and increased intracellular reactive oxygen species (ROS) levels. Treatment of the cells with the ROS scavenger N-acetyl-l-cysteine (NAC) resulted in strongly decreased intracellular ROS levels and reduced DNA damage. However, a slow increase of ROS after ZnO NP exposure and reduced but not quashed DSBs after NAC-treatment suggest that Zn(2+) may exert genotoxic activities without the necessity of preceding ROS-induction. Our data indicate that ZnO NP toxicity is a result of cellular Zn(2+) intake. Subsequently increased ROS-levels cause DNA damage. However, we found

  12. Organic crystal light-emitting transistors combined with a metal oxide layer

    NASA Astrophysics Data System (ADS)

    Obara, Keiji; Higashihara, Shohei; Yamao, Takeshi; Hotta, Shu

    2016-03-01

    We improved organic light-emitting transistors (OLETs) characterized by aluminum-doped zinc oxide (AZO) layer insertion between organic and gate insulator layers using organic oligomer semiconductor crystals. (i) To ensure firm contact between the crystal and the AZO layer, we shaped the AZO layer into a rectangle (250 × 500 µm2) and covered it with a vapor-phase-grown crystal. (ii) To enhance contact between the crystal and the AZO layer, we placed the crystal used as a mask on the patternless AZO layer and etched parts of AZO not covered with the crystal with hydrochloric acid vapor. We completed OLETs by forming electron- and hole-injection contacts on the crystal. We modified these contacts with an oxide and/or a carbonate. The devices showed bright light emission from the part of the crystal sandwiched between the electron- and hole-injection contacts located on the AZO layer.

  13. Genotoxic effects of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Heim, Julia; Felder, Eva; Tahir, Muhammad Nawaz; Kaltbeitzel, Anke; Heinrich, Ulf Ruediger; Brochhausen, Christoph; Mailänder, Volker; Tremel, Wolfgang; Brieger, Juergen

    2015-05-01

    The potential toxicity of nanoparticles has currently provoked public and scientific discussions, and attempts to develop generally accepted handling procedures for nanoparticles are under way. The investigation of the impact of nanoparticles on human health is overdue and reliable test systems accounting for the special properties of nanomaterials must be developed. Nanoparticular zinc oxide (ZnO) may be internalised through ambient air or the topical application of cosmetics, only to name a few, with unpredictable health effects. Therefore, we analysed the determinants of ZnO nanoparticle (NP) genotoxicity. ZnO NPs (15-18 nm in diameter) were investigated at concentrations of 0.1, 10 and 100 μg mL-1 using the cell line A549. Internalised NPs were only infrequently detectable by TEM, but strongly increased Zn2+ levels in the cytoplasm and even more in the nuclear fraction, as measured by atom absorption spectroscopy, indicative of an internalised zinc and nuclear accumulation. We observed a time and dosage dependent reduction of cellular viability after ZnO NP exposure. ZnCl2 exposure to cells induced similar impairments of cellular viability. Complexation of Zn2+ with diethylene triamine pentaacetic acid (DTPA) resulted in the loss of toxicity of NPs, indicating the relevant role of Zn2+ for ZnO NP toxicity. Foci analyses showed the induction of DNA double strand breaks (DSBs) by ZnO NPs and increased intracellular reactive oxygen species (ROS) levels. Treatment of the cells with the ROS scavenger N-acetyl-l-cysteine (NAC) resulted in strongly decreased intracellular ROS levels and reduced DNA damage. However, a slow increase of ROS after ZnO NP exposure and reduced but not quashed DSBs after NAC-treatment suggest that Zn2+ may exert genotoxic activities without the necessity of preceding ROS-induction. Our data indicate that ZnO NP toxicity is a result of cellular Zn2+ intake. Subsequently increased ROS-levels cause DNA damage. However, we found evidence for

  14. Genotoxic effects of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Heim, Julia; Felder, Eva; Tahir, Muhammad Nawaz; Kaltbeitzel, Anke; Heinrich, Ulf Ruediger; Brochhausen, Christoph; Mailänder, Volker; Tremel, Wolfgang; Brieger, Juergen

    2015-05-01

    The potential toxicity of nanoparticles has currently provoked public and scientific discussions, and attempts to develop generally accepted handling procedures for nanoparticles are under way. The investigation of the impact of nanoparticles on human health is overdue and reliable test systems accounting for the special properties of nanomaterials must be developed. Nanoparticular zinc oxide (ZnO) may be internalised through ambient air or the topical application of cosmetics, only to name a few, with unpredictable health effects. Therefore, we analysed the determinants of ZnO nanoparticle (NP) genotoxicity. ZnO NPs (15-18 nm in diameter) were investigated at concentrations of 0.1, 10 and 100 μg mL-1 using the cell line A549. Internalised NPs were only infrequently detectable by TEM, but strongly increased Zn2+ levels in the cytoplasm and even more in the nuclear fraction, as measured by atom absorption spectroscopy, indicative of an internalised zinc and nuclear accumulation. We observed a time and dosage dependent reduction of cellular viability after ZnO NP exposure. ZnCl2 exposure to cells induced similar impairments of cellular viability. Complexation of Zn2+ with diethylene triamine pentaacetic acid (DTPA) resulted in the loss of toxicity of NPs, indicating the relevant role of Zn2+ for ZnO NP toxicity. Foci analyses showed the induction of DNA double strand breaks (DSBs) by ZnO NPs and increased intracellular reactive oxygen species (ROS) levels. Treatment of the cells with the ROS scavenger N-acetyl-l-cysteine (NAC) resulted in strongly decreased intracellular ROS levels and reduced DNA damage. However, a slow increase of ROS after ZnO NP exposure and reduced but not quashed DSBs after NAC-treatment suggest that Zn2+ may exert genotoxic activities without the necessity of preceding ROS-induction. Our data indicate that ZnO NP toxicity is a result of cellular Zn2+ intake. Subsequently increased ROS-levels cause DNA damage. However, we found evidence for

  15. Thermodynamics and kinetics of extracting zinc from zinc oxide ore by the ammonium sulfate roasting method

    NASA Astrophysics Data System (ADS)

    Sun, Yi; Shen, Xiao-yi; Zhai, Yu-chun

    2015-05-01

    Thermodynamic analyses and kinetic studies were performed on zinc oxide ore treatment by (NH4)2SO4 roasting technology. The results show that it is theoretically feasible to realize a roasting reaction between the zinc oxide ore and (NH4)2SO4 in a temperature range of 573-723 K. The effects of reaction temperature and particle size on the extraction rate of zinc were also examined. It is found that a surface chemical reaction is the rate-controlling step in roasting kinetics. The calculated activation energy of this process is about 45.57 kJ/mol, and the kinetic model can be expressed as follows: 1 - (1 - α)1/3 = 30.85 exp(-45.57/ RT)· t. An extraction ratio of zinc as high as 92% could be achieved under the optimum conditions.

  16. Zinc-oxide-based nanostructured materials for heterostructure solar cells

    SciTech Connect

    Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A. Somov, P. A.; Terukov, E. I.

    2015-10-15

    Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

  17. AZO/Ag/AZO anode for resonant cavity red, blue, and yellow organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Gentle, A. R.; Yambem, S. D.; Burn, P. L.; Meredith, P.; Smith, G. B.

    2016-06-01

    Indium tin oxide (ITO) is the transparent electrode of choice for organic light-emitting diodes (OLEDs). Replacing ITO for cost and performance reasons is a major drive across optoelectronics. In this work, we show that changing the transparent electrode on red, blue, and yellow OLEDs from ITO to a multilayer buffered aluminium zinc oxide/silver/aluminium zinc oxide (AZO/Ag/AZO) substantially enhances total output intensity, with better control of colour, its constancy, and intensity over the full exit hemisphere. The thin Ag containing layer induces a resonant cavity optical response of the complete device. This is tuned to the emission spectra of the emissive material while minimizing internally trapped light. A complete set of spectral intensity data is presented across the full exit hemisphere for each electrode type and each OLED colour. Emission zone modelling of output spectra at a wide range of exit angles to the normal was in excellent agreement with the experimental data and hence could, in principle, be used to check and adjust production settings. These multilayer transparent electrodes show significant potential for both eliminating indium from OLEDs and spectrally shaping the emission.

  18. Plasma in-liquid method for reduction of zinc oxide in zinc nanoparticle synthesis

    NASA Astrophysics Data System (ADS)

    Amaliyah, Novriany; Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Kitamae, Tomohide

    2015-02-01

    Metal air-batteries with high-energy density are expected to be increasingly applied in electric vehicles. This will require a method of recycling air batteries, and reduction of metal oxide by generating plasma in liquid has been proposed as a possible method. Microwave-induced plasma is generated in ethanol as a reducing agent in which zinc oxide is dispersed. Analysis by energy-dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD) reveals the reduction of zinc oxide. According to images by transmission electron microscopy (TEM), cubic and hexagonal metallic zinc particles are formed in sizes of 30 to 200 nm. Additionally, spherical fiber flocculates approximately 180 nm in diameter are present.

  19. Microstructure evolution of Al-doped zinc oxide and Sn-doped indium oxide deposited by radio-frequency magnetron sputtering: A comparison

    SciTech Connect

    Nie, Man; Bikowski, Andre; Ellmer, Klaus

    2015-04-21

    The microstructure and morphology evolution of Al-doped zinc oxide (AZO) and Sn-doped indium oxide (ITO) thin films on borosilicate glass substrates deposited by radio-frequency magnetron sputtering at room temperature (RT) and 300 °C were investigated by X-ray diffraction and atomic force microscopy (AFM). One-dimensional power spectral density (1DPSD) functions derived from the AFM profiles, which can be used to distinguish different growth mechanisms, were used to compare the microstructure scaling behavior of the thin films. The rms roughness R{sub q} evolves with film thickness as a power law, R{sub q} ∼ d{sub f}{sup β}, and different growth exponents β were found for AZO and ITO films. For AZO films, β of 1.47 and 0.56 are obtained for RT and 300 °C depositions, respectively, which are caused by the high compressive stress in the film at RT and relaxation of the stress at 300 °C. While for ITO films, β{sub 1} = 0.14 and β{sub 2} = 0.64 for RT, and β{sub 1} = 0.89 and β{sub 2} = 0.3 for 300 °C deposition are obtained, respectively, which is related to the strong competition between the surface diffusion and shadowing effect and/or grain growth. Electrical properties of both materials as a function of film thickness were also compared. By the modified Fuchs-Sondheimer model fitting of the electrical transport in both materials, different nucleation states are pointed out for both types of films.

  20. A new copper species based on an azo-compound utilized as a homogeneous catalyst for water oxidation.

    PubMed

    Yu, Wei-Bin; He, Qing-Ya; Ma, Xiu-Fang; Shi, Hua-Tian; Wei, Xianwen

    2015-01-01

    A new azo-complex [(L)Cu(II)(NO3)] [L = (E)-3-(pyridin-2-yldiazenyl)naphthalen-2-ol (HL)], was prepared via a one-pot synthetic method at 60 °C and was structurally characterized by IR, EA, PXRD and single crystal X-ray diffraction. In addition, TGA studies indicated that the complex was stable in air. The redox properties were determined by cyclic voltammetry, which revealed that the complex could be utilized as a catalyst for water oxidation under mild conditions. Subsequently, the complex was employed as a catalyst to take part in water oxidation reaction in the presence of a Ce(IV) salt utilized as an oxidant at pH 11 in PBS (Phosphate Buffered Saline) solution. The results suggested that the catalyst exhibited a high stability and activity toward water oxidation reaction under these conditions with an initial TOF of 4.0 kPa h(-1). Calculation methodology was performed to study the mechanism of the reaction, which revealed that in this catalytic process, the initial oxidation of Cu(II) to Cu(III) occurred by the formation of an intermediate "Cu(III)-O-O-Cu(III)". The formation of this intermediate, resulted in a release of oxygen and closing of the catalytic cycle.

  1. Optical cavity modes of a single crystalline zinc oxide microsphere.

    PubMed

    Moirangthem, Rakesh Singh; Cheng, Pi-Ju; Chien, Paul Ching-Hang; Ngo, Buu Trong Huynh; Chang, Shu-Wei; Tien, Chung-Hao; Chang, Yia-Chung

    2013-02-11

    A detailed study on the optical cavity modes of zinc oxide microspheres under the optical excitation is presented. The zinc oxide microspheres with diameters ranging from 1.5 to 3.0 µm are prepared using hydrothermal growth technique. The photoluminescence measurement of a single microsphere shows prominent resonances of whispering gallery modes at room temperature. The experimentally observed whispering gallery modes in the photoluminescence spectrum are compared with theoretical calculations using analytical and finite element methods in order to clarify resonance properties of these modes. The comparison between theoretical analysis and experiment suggests that the dielectric constant of the ZnO microsphere is somewhat different from that for bulk ZnO. The sharp resonances of whispering gallery modes in zinc oxide microspheres cover the entire visible window. They may be utilized in realizations of optical resonators, light emitting devices, and lasers for future chip integrations with micro/nano optoelectronic circuits, and developments of optical biosensors. PMID:23481759

  2. Zinc oxide nanoparticles for revolutionizing agriculture: synthesis and applications.

    PubMed

    Sabir, Sidra; Arshad, Muhammad; Chaudhari, Sunbal Khalil

    2014-01-01

    Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles. PMID:25436235

  3. Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications

    PubMed Central

    Sabir, Sidra; Arshad, Muhammad

    2014-01-01

    Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles. PMID:25436235

  4. Zinc oxide nanoparticles for revolutionizing agriculture: synthesis and applications.

    PubMed

    Sabir, Sidra; Arshad, Muhammad; Chaudhari, Sunbal Khalil

    2014-01-01

    Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles.

  5. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-10-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2-4 nm) nanoparticles.

  6. Thin zinc oxide and cuprous oxide films for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Jeong, Seongho

    Metal oxide semiconductors and heterojunctions made from thin films of metal oxide semiconductors have broad range of functional properties and high potential in optical, electrical and magnetic devices such as light emitting diodes, spintronic devices and solar cells. Among the oxide semiconductors, zinc oxide (ZnO) and cuprous oxide (Cu2O) are attractive because they are inexpensive, abundant and nontoxic. As synthesized ZnO is usually an intrinsic n - type semiconductor with wide band gap (3.4 eV) and can be used as the transparent conducting window layer in solar cells. As synthesized Cu2O is usually a p - type semiconductor with a band gap of 2.17 eV and has been considered as a potential material for the light absorbing layer in solar cells. I used various techniques including metal organic chemical vapor deposition, magnetron sputtering and atomic layer deposition to grow thin films of ZnO and Cu2O and fabricated Cu2O/ZnO heterojunctions. I specifically investigated the optical and electrical properties of Cu 2O thin films deposited on ZnO by MOCVD and showed that Cu2O thin films grow as single phase with [110] axis aligned perpendicular to the ZnO surface which is (0001) plane and with in-plane rotational alignment due to (220) Cu2O || (0002)ZnO; [001]Cu2O || [12¯10]ZnO epitaxy. Moreover, I fabricated solar cells based on these Cu2O/ZnO heterojunctions and characterized them. Electrical characterization of these solar cells as a function of temperature between 100 K and 300 K under illumination revealed that interface recombination and tunneling at the interface are the factors that limit the solar cell performance. To date solar cells based on Cu2O/ZnO heterojunctions had low open circuit voltages (~ 0.3V) even though the expected value is around 1V. I achieved open circuit voltages approaching 1V at low temperature (~ 100 K) and showed that if interfacial recombination is reduced these cells can achieve their predicted potential.

  7. Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach

    NASA Astrophysics Data System (ADS)

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; van Dorsselaer, Alain; Rabilloud, Thierry

    2014-05-01

    Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate

  8. Sealed silver oxide zinc cells for orbiting and planetary missions.

    NASA Technical Reports Server (NTRS)

    Hennigan, T. J.; Palandati, C. F.

    1972-01-01

    Several test programs were carried out to determine the performance and limitations of sealed, silver oxide zinc cells for (1) 24-hr synchronous orbits, (2) orbits that would require a maximum of six cycles per day, and (3) missions to other planets requiring maintenance of maximum capacity for probe operations during planet encounter. The results are summarized to provide power system designers with guidelines bearing on capacity maintenance during cycling, cycle life, charged stand effects, and internal pressure characteristics. The life of zinc silver oxide cells is shown to be limited to one to two years over the temperature range of 0 to 24 C.

  9. Hydrogen Reduction of Zinc and Iron Oxides Containing Mixtures

    NASA Astrophysics Data System (ADS)

    de Siqueira, Rogério Navarro C.; de Albuquerque Brocchi, Eduardo; de Oliveira, Pamela Fernandes; Motta, Marcelo Senna

    2013-10-01

    Zinc is a metal of significant technological importance and its production from secondary sources has motivated the development of alternative processes, such as the chemical treatment of electrical arc furnace (EAF) dust. Currently, the extraction of zinc from the mentioned residue using a carbon-containing reducing agent is in the process of being established commercially and technically. In the current study, the possibility of reducing zinc from an EAF dust sample through a H2 constant flux in a horizontal oven is studied. The reduction of a synthetic oxide mixture of analogous composition is also investigated. The results indicated that the reduction process is thermodynamically viable for temperatures higher than 1123 K (850 °C), and all zinc metal produced is transferred to the gas stream, enabling its complete separation from iron. The same reaction in the presence of zinc crystals was considered for synthesizing FeZn alloys. However, for the experimental conditions employed, although ZnO reduction was indeed thermodynamically hindered because of the presence of zinc crystals (the metal's partial pressure was enhanced), the zinc metal's escape within the gaseous phase could not be effectively avoided.

  10. The oxidation of Ni(II) N-confused porphyrins (NCPs) with azo radical initiators and an unexpected intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate.

    PubMed

    Jiang, Hua-Wei; Chen, Qing-Yun; Xiao, Ji-Chang; Gu, Yu-Cheng

    2009-07-01

    The oxidation of Ni(II) N-confused porphyrins (NCPs) with azo radical initiators resulted in an unexpected intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate, which could be detected by HRMS.

  11. Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide

    NASA Astrophysics Data System (ADS)

    Acarali, Nil Baran; Bardakci, Melek; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

    2013-06-01

    The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1-5 h), reactant ratio (H3BO3/ZnO by mass: 2-5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0-2wt%), reaction temperature (50-120°C), cooling temperature (10-80°C), and stirring rate (400-700 r/min); the modifying agents involve propylene glycol (PG, 0-6wt%), kerosene (1wt%-6wt%), and oleic acid (OA, 1wt%-6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

  12. Synthesis of 5-aminotetrazole-1N-oxide and its azo derivative: a key step in the development of new energetic materials.

    PubMed

    Fischer, Dennis; Klapötke, Thomas M; Piercey, Davin G; Stierstorfer, Jörg

    2013-04-01

    1-Hydroxy-5-aminotetrazole (1), which is a long-desired starting material for the synthesis of hundreds of new energetic materials, was synthesized for the first time by the reaction of aqueous hydroxylamine with cyanogen azide. The use of this unique precursor was demonstrated by the preparation of several energetic compounds with equal or higher performance than that of commonly used explosives, such as hexogen (RDX). The prepared compounds, including energetic salts of 1-hydroxy-5-aminotetrazole (hydroxylammonium (2, two polymorphs) and ammonium (3)), azo-coupled derivatives (potassium (5), hydroxylammonium (6), ammonium (7), and hydrazinium 5,5'-azo-bis(1-N-oxidotetrazolate (8, two polymorphs)), as well as neutral compounds 5,5'-azo-bis(1-oxidotetrazole) (4) and 5,5'-bis(1-oxidotetrazole)hydrazine (9), were intensively characterized by low-temperature X-ray diffraction, IR, Raman, and multinuclear NMR spectroscopy, elemental analysis, and DSC. The calculated energetic performance, by using the EXPLO5 code, based on the calculated (CBS-4M) heats of formation and X-ray densities confirm the high energetic performance of tetrazole-N-oxides as energetic materials. Last but not least, their sensitivity towards impact, friction, and electrostatic discharge were explored. 5,5'-Azo-bis(1-N-oxidotetrazole) deflagrates close to the DDT (deflagration-to-detonation transition) faster than all compounds that have been investigated in our research group to date. PMID:23417994

  13. Synthesis of 5-aminotetrazole-1N-oxide and its azo derivative: a key step in the development of new energetic materials.

    PubMed

    Fischer, Dennis; Klapötke, Thomas M; Piercey, Davin G; Stierstorfer, Jörg

    2013-04-01

    1-Hydroxy-5-aminotetrazole (1), which is a long-desired starting material for the synthesis of hundreds of new energetic materials, was synthesized for the first time by the reaction of aqueous hydroxylamine with cyanogen azide. The use of this unique precursor was demonstrated by the preparation of several energetic compounds with equal or higher performance than that of commonly used explosives, such as hexogen (RDX). The prepared compounds, including energetic salts of 1-hydroxy-5-aminotetrazole (hydroxylammonium (2, two polymorphs) and ammonium (3)), azo-coupled derivatives (potassium (5), hydroxylammonium (6), ammonium (7), and hydrazinium 5,5'-azo-bis(1-N-oxidotetrazolate (8, two polymorphs)), as well as neutral compounds 5,5'-azo-bis(1-oxidotetrazole) (4) and 5,5'-bis(1-oxidotetrazole)hydrazine (9), were intensively characterized by low-temperature X-ray diffraction, IR, Raman, and multinuclear NMR spectroscopy, elemental analysis, and DSC. The calculated energetic performance, by using the EXPLO5 code, based on the calculated (CBS-4M) heats of formation and X-ray densities confirm the high energetic performance of tetrazole-N-oxides as energetic materials. Last but not least, their sensitivity towards impact, friction, and electrostatic discharge were explored. 5,5'-Azo-bis(1-N-oxidotetrazole) deflagrates close to the DDT (deflagration-to-detonation transition) faster than all compounds that have been investigated in our research group to date.

  14. Application of zinc oxide quantum dots in food safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc oxide quantum dots (ZnO QDs) are nanoparticles of purified powdered ZnO. The ZnO QDs were directly added into liquid foods or coated on the surface of glass jars using polylactic acid (PLA) as a carrier. The antimicrobial activities of ZnO QDs against Listeria monocytogenes, Salmonella Enteriti...

  15. Potassium silicate-zinc oxide solution for metal finishes

    NASA Technical Reports Server (NTRS)

    Schutt, J. B.

    1970-01-01

    Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1.

  16. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1991-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  17. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1991-11-05

    Disclosed are a new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  18. Chemical vapor deposition of fluorine-doped zinc oxide

    DOEpatents

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

    2000-06-06

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

  19. 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.

  20. Epitaxial Growth of Zinc Oxide on Single Crystalline Gold Plates

    NASA Astrophysics Data System (ADS)

    Greenberg, Kathryn; Joo, John; Baram, Mor; Clarke, David; Hu, Evelyn

    2012-02-01

    Although metal-oxide interfaces are the critical components of many electronic and optical devices, it is rare to find epitaxial metal-oxide structures. We demonstrate for the first time, a method for the low temperature, epitaxial growth of zinc oxide (ZnO) on single crystalline gold plates. The gold plates, up to 100μm in width, are grown from a gold-surfactant complex. Even with the large lattice mismatch between (111) gold and (0001) ZnO, we are able to form epitaxial zinc oxide at 90^oC on top of the single crystal gold plates. This epitaxial growth is confirmed using transmission electron microscopy, electron diffraction, and electron backscatterer diffraction. Micro-photoluminescence is also performed to investigate the optical properties of the epitaxial zinc oxide. We remove the grown ZnO membranes from the gold plates using a stamping and etching process. These membranes can potentially be used to fabricate high quality microdisks and photonic crystals. The metal-oxide interfaces that we have fabricated may have the ability to be used in a number of technologically important applications, including as better electrical contacts and for improved light extraction from planar LED structures.

  1. Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach.

    PubMed

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; Van Dorsselaer, Alain; Rabilloud, Thierry

    2014-06-01

    Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.

  2. Doping in zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Yang, Zheng

    Doping in zinc oxide (ZnO) thin films is discussed in this dissertation. The optimizations of undoped ZnO thin film growth using molecular-beam epitaxy (MBE) are discussed. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher growth rate, better crystallinity, lower electron carrier concentration, larger resistivity, and smaller density of non-radiative luminescence centers in the ZnO thin films. Low-temperature photoluminescence (PL) measurements were carried out in undoped and Ga-doped ZnO thin films grown by molecular-beam epitaxy. As the carrier concentration increases from 1.8 x 1018 to 1.8 x 1020 cm-3, the dominant PL line at 9 K changes from I1 (3.368--3.371 eV), to IDA (3.317--3.321 eV), and finally to I8 (3.359 eV). The dominance of I1, due to ionized-donor bound excitons, is unexpected in n-type samples, but is shown to be consistent with the temperature-dependent Hall fitting results. We also show that IDA has characteristics of a donor-acceptor-pair transition, and use a detailed, quantitative analysis to argue that it arises from GaZn donors paired with Zn-vacancy (VZn) acceptors. In this analysis, the GaZn0/+ energy is well-known from two-electron satellite transitions, and the VZn0/- energy is taken from a recent theoretical calculation. Typical behaviors of Sb-doped p-type ZnO are presented. The Sb doping mechanisms and preference in ZnO are discussed. Diluted magnetic semiconducting ZnO:Co thin films with above room-temperature TC were prepared. Transmission electron microscopy and x-ray diffraction studies indicate the ZnO:Co thin films are free of secondary phases. The magnetization of the ZnO:Co thin films shows a free electron carrier concentration dependence, which increases dramatically when the free electron carrier concentration exceeds ˜1019 cm -3, indicating a carrier-mediated mechanism for

  3. Kinetics of the dissolution of zinc sulfide in an oxidizing slag

    NASA Astrophysics Data System (ADS)

    Gupta, Suresh K.

    1990-10-01

    A new concept has been developed for the production of zinc from zinc and complex zinc concentrates. It is a two-stage process involving oxidation of zinc sulfide to oxide and dissolution into slag and the fuming of zinc from the slag by injecting carbonaceous materials into it to produce zinc vapors which can be subsequently condensed in a lead-splash condenser such as those used in the Imperial Smelting Process (ISP). In this paper, the effects of the quantity of air, temperature, and concentrate feed rate have been discussed on the production of zinc-rich slag, which is the first stage of the proposed process.

  4. Biodecolorization of azo dye Remazol orange by Pseudomonas aeruginosa BCH and toxicity (oxidative stress) reduction in Allium cepa root cells.

    PubMed

    Jadhav, Shekhar B; Surwase, Shripad N; Kalyani, Dayanand C; Gurav, Ranjit G; Jadhav, Jyoti P

    2012-11-01

    In this report a textile azo dye Remazol orange was degraded and detoxified by bacterium Pseudomonas aeruginosa BCH in plain distilled water. This bacterial decolorization performance was found to be pH and temperature dependent with maximum decolorization observed at pH 8 and temperature 30 °C. Bacterium tolerated higher dye concentrations up to 400 mg l(-1). Effect of initial cell mass showed that higher cell mass concentration can accelerate decolorization process with maximum of 92 % decolorization observed at 2.5 g l(-1) cell mass within 6.5 h. Effect of various metal ions showed Mn has inducing effect whereas Zn strongly inhibited the decolorization process at 5 mM concentration. Analysis of biodegradation products carried out with UV-vis spectroscopy, HPTLC and FTIR confirmed the decolorization and degradation of Remazol orange. Possible route for the degradation of dye was proposed based on GC-MS analysis. During toxicological scrutiny in Allium cepa root cells, induction in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and inhibition of catalase (CAT) along with raised levels of lipid peroxidation and protein oxidation in dye treated samples were detected which conclusively indicated the generation of oxidative stress. Less toxic nature of the dye degraded products was observed after bacterial treatment.

  5. Biodecolorization of azo dye Remazol orange by Pseudomonas aeruginosa BCH and toxicity (oxidative stress) reduction in Allium cepa root cells.

    PubMed

    Jadhav, Shekhar B; Surwase, Shripad N; Kalyani, Dayanand C; Gurav, Ranjit G; Jadhav, Jyoti P

    2012-11-01

    In this report a textile azo dye Remazol orange was degraded and detoxified by bacterium Pseudomonas aeruginosa BCH in plain distilled water. This bacterial decolorization performance was found to be pH and temperature dependent with maximum decolorization observed at pH 8 and temperature 30 °C. Bacterium tolerated higher dye concentrations up to 400 mg l(-1). Effect of initial cell mass showed that higher cell mass concentration can accelerate decolorization process with maximum of 92 % decolorization observed at 2.5 g l(-1) cell mass within 6.5 h. Effect of various metal ions showed Mn has inducing effect whereas Zn strongly inhibited the decolorization process at 5 mM concentration. Analysis of biodegradation products carried out with UV-vis spectroscopy, HPTLC and FTIR confirmed the decolorization and degradation of Remazol orange. Possible route for the degradation of dye was proposed based on GC-MS analysis. During toxicological scrutiny in Allium cepa root cells, induction in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and inhibition of catalase (CAT) along with raised levels of lipid peroxidation and protein oxidation in dye treated samples were detected which conclusively indicated the generation of oxidative stress. Less toxic nature of the dye degraded products was observed after bacterial treatment. PMID:22948606

  6. 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.

  7. Sulfidation and reduction of zinc titanate and zinc oxide sorbents for injection in gasifier exit ducts

    SciTech Connect

    Ishikawa, K. |; Krueger, C.; Flytzani-Stephanopoulos, M.; Jl, W.; Higgins, R.J.; Bishop, B.A.; Goldsmith, R.L.

    1995-12-31

    The sulfidation reaction kinetics of fine particles of zinc titanate and zinc oxide with H{sub 2}S were studied in order to test the potential of the sorbent injection hot-gas desulfurization process. Fine sorbent particles with diameter between 0.3 and 60 {mu}m were sulfided with H{sub 2}S and/or reduced with H{sub 2} in a laminar flow reactor over the temperature range of 500-900{degrees}C. Sulfidation/reduction conversion was compared for different particle sizes and sorbents with various porosities and atomic ratios of Zn and Ti. In reduction of ZnO with H{sub 2} and without H{sub 2}S, significant amount of Zn was formed and vaporized, while the presence of H{sub 2}S suppressed elemental Zn formation. This suggests that H{sub 2}S may suppress the surface reduction of ZnO and/or gaseous Zn may react with H{sub 2}S homogeneously and form fine particles of ZnS. Formation and vaporization of elemental Zn from zinc titanate sorbents was slower than from zinc oxide with and without H{sub 2}S.

  8. Quantum Monte Carlo models of substitutional point defects in zinc oxide and zinc selenide

    NASA Astrophysics Data System (ADS)

    Yu, Jaehyung; Ertekin, Elif

    2015-03-01

    Introducing dopants into semiconductors allows manipulation of electrical and optical properties, useful for applications such as optoelectronics and photovoltaics. While first principles quantitative descriptions of the defects properties in semiconductors are critical to understanding and engineering dopants in semiconductors, obtaining accurate descriptions has proven challenging in the past. Here we demonstrate the use of quantum Monte Carlo (QMC) methods to describing the properties of point defects in zinc oxide and zinc selenide. Due to its direct treatment of electron correlation, the QMC method is capable of accurate calculation of band gaps and defect behaviors. We describe the energetics and potential barrier to forming gallium DX-center defects according to QMC in zinc selenide, and compare the description to those of conventional and hybrid DFT. We also use QMC to determine the defect transition levels for nitrogen defects in zinc oxide, and show that QMC obtains descriptions that are in good agreement with GW and beyond-DFT approaches. Our results demonstrate the importance of accurate descriptions of electron correlation in the calculation of defect properties of semiconductors.

  9. Supermicroporous alumina-silica zinc oxides

    SciTech Connect

    Shpeizer, Boris G; Bakhmutov, Vladimir I; Clearfield, Abraham

    2008-09-29

    A new family of porous mixed oxides with pores largely in the 8-20 {angstrom} range have been prepared. TEOS acts as a solvent and as a source of silica to which aluminum butoxide and transition metal acetates are added. Neutral amines are added as templates and to effect hydrolysis. This paper describes the ZnO-Al{sub 2}O{sub 5}-SiO{sub 2} system but similar results have been obtained with other transition metal oxides. An interesting feature of the technique is that the larger the amine template the greater is the surface area of the mixed oxide with only a slight increase in the average pore diameter. Both NMR and atomic pair distribution functional methods have been used to prove the homogeneity of the mixed oxide products. This preparative method complements our earlier report in Chemical Communications on mixed oxides prepared with ZrO{sub 2} and TiO{sub 2} incorporating transition metal oxides.

  10. A long life zinc oxide-titanium oxide sorbent for moving bed reactors

    SciTech Connect

    Copeland, R.; Cesario, M.; Dubovik, M.; Feinberg, D.; Windecker, B.; Yang, J.

    1996-12-31

    Coal Fired Gasifier Combined Cycles (GCCs) have both high efficiency and very low emissions. GCCs are in critical need of a method to remove the H{sub 2}S produced from the sulfur in the coal from the hot gases. There has been extensive research on hot gas clean-up systems, focused on the use of a zinc oxide based sorbent (e.g., zinc titanate). However, the previous sorbents show significant losses in sulfur capacity with cycling. TDA Research, Inc. recently increased the zinc oxide content and sulfur loadings while simultaneously improving the attrition resistance. The improved fabrication method produces long life, low cost sorbent containing zinc oxide. The authors are currently testing sorbents at conditions simulating a moving bed reactor for GCC [i.e., 20 atm, 482 C (900 F) to 538 C (1,000 F), and 1% H{sub 2}S].

  11. Degradation of hydrocortisone in a zinc oxide lotion.

    PubMed

    Timmins, P; Gray, E A

    1983-03-01

    An extemporaneous topical steroid formulation, prepared from a zinc oxide lotion and hydrocortisone lotion BPC, had poor stability. Hydrocortisone decomposed mainly to the 21-aldehyde, but other degradation products were also identified by HPLC. The decomposition process could be described by first-order kinetics. Stabilization methods employing pH adjustment, antioxidants and chelating agents were unsuccessful. The study emphasizes the dangers of diluting commercial formulations with unrecommended bases and indicates the modes of decomposition of hydrocortisone in a formulation.

  12. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.

    PubMed

    Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

    2014-12-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host.

  13. Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

    PubMed Central

    Pike, Sebastian D.; White, Edward R.; Shaffer, Milo S. P.; Williams, Charlotte K.

    2016-01-01

    The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2–4 nm) nanoparticles. PMID:27734828

  14. 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.

  15. Superior antibacterial activity of zinc oxide/graphene oxide composites originating from high zinc concentration localized around bacteria.

    PubMed

    Wang, Yan-Wen; Cao, Aoneng; Jiang, Yu; Zhang, Xin; Liu, Jia-Hui; Liu, Yuanfang; Wang, Haifang

    2014-02-26

    New materials with good antibacterial activity and less toxicity to other species attract numerous research interest. Taking advantage of zinc oxide (ZnO) and graphene oxide (GO), the ZnO/GO composites were prepared by a facile one-pot reaction to achieve superior antibacterial properties without damaging other species. In the composites, ZnO nanoparticles (NPs), with a size of about 4 nm, homogeneously anchored onto GO sheets. The typical bacterium Escherichia coli and HeLa cell were used to evaluate the antibacterial activity and cytotoxicity of the ZnO/GO composites, respectively. The synergistic effects of GO and ZnO NPs led to the superior antibacterial activity of the composites. GO helped the dispersion of ZnO NPs, slowed the dissolution of ZnO, acted as the storage site for the dissolved zinc ions, and enabled the intimate contact of E. coli with ZnO NPs and zinc ions as well. The close contact enhanced the local zinc concentration pitting on the bacterial membrane and the permeability of the bacterial membrane and thus induced bacterial death. In addition, the ZnO/GO composites were found to be much less toxic to HeLa cells, compared to the equivalent concentration of ZnO NPs in the composites. The results indicate that the ZnO/GO composites are promising disinfection materials to be used in surface coatings on various substrates to effectively inhibit bacterial growth, propagation, and survival in medical devices.

  16. Zinc in the prevention of Fe2+-initiated lipid and protein oxidation.

    PubMed

    Zago, M P; Verstraeten, S V; Oteiza, P I

    2000-01-01

    In the present study we characterized the capacity of zinc to protect lipids and proteins from Fe2+-initiated oxidative damage. The effects of zinc on lipid oxidation were investigated in liposomes composed of brain phosphatidylcholine (PC) and phosphatidylserine (PS) at a molar relationship of 60:40 (PC:PS, 60:40). Lipid oxidation was evaluated as the oxidation of cis-parinaric acid or as the formation of 2-thiobarbituric acid-reactive substances (TBARS). Zinc protected liposomes from Fe2+ (2.5-50 microM)-supported lipid oxidation. However, zinc (50 microM) did not prevent the oxidative inactivation of glutamine synthetase and glucose 6-phosphate dehydrogenase when rat brain supernatants were oxidized in the presence of 5 microM Fe2+ and 0.5 mM H2O2. We also studied the interactions of zinc with epicatechin in the prevention of lipid oxidation in liposomes. The simultaneous addition of 0.5 microM epicatechin (EC) and 50 microM zinc increased the protection of liposomes from oxidation compared to that observed in the presence of zinc or EC separately. Zinc (50 microM) also protected liposomes from the stimulatory effect of aluminum on Fe2+-initiated lipid oxidation. Zinc could play an important role as an antioxidant in biological systems, replacing iron and other metals with pro-oxidant activity from binding sites and interacting with other components of the oxidant defense system. PMID:15693281

  17. Enzymes oxidizing the azo dye 1-phenylazo-2-naphthol (Sudan I) and their contribution to its genotoxicity and carcinogenicity.

    PubMed

    Stiborova, Marie; Schmeiser, Heinz H; Frei, Eva; Hodek, Petr; Martinek, Vaclav

    2014-01-01

    Sudan I [1-(phenylazo)-2-naphthol, C.I. Solvent Yellow 14] is an industrial dye, which was found as a contaminant in numerous foods in several European countries. Because Sudan I has been assigned by the IARC as a Category 3 carcinogen, the European Union decreed that it cannot be utilized as food colorant in any European country. Sudan I induces the malignancies in liver and urinary bladder of rats and mice. This carcinogen has also been found to be a potent mutagen, contact allergen and sensitizer, and exhibits clastogenic properties. The oxidation of Sudan I increases its toxic effects and leads to covalent adducts in DNA. Identification of enzymatic systems that contribute to Sudan I oxidative metabolism to reactive intermediates generating such covalent DNA adducts on the one hand, and to the detoxification of this carcinogen on the other, is necessary to evaluate susceptibility to this toxicant. This review summarizes the identification of such enzymes and the molecular mechanisms of oxidation reactions elucidated to date. Human and animal cytochrome P450 (CYP) and peroxidases are capable of oxidizing Sudan I. Of the CYP enzymes, CYP1A1 is most important both in Sudan I detoxification and its bio-activation. Ring-hydroxylated metabolites and a dimer of this carcinogen were found as detoxification products of Sudan I generated with CYPs and peroxidases, respectively. Oxidative bio-activation of this azo dye catalyzed by CYPs and peroxidases leads to generation of proximate genotoxic metabolites (the CYP-catalyzed formation of the benzenediazonium cation and the peroxidase-mediated generation of one-electron oxidation products), which covalently modify DNA both in vitro and in vivo. The predominant DNA adduct generated with the benzenediazonium cation was characterized to be 8-(phenylazo)guanine. The Sudan I radical species mediated by peroxidases reacts with the -NH2 group in (deoxy)guanosine, generating the 4-[(deoxy)guanosin-N(2)-yl]Sudan I product. Sudan I

  18. Zinc-oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasael

    2010-03-23

    Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  19. Zinc oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2005-10-04

    Zinc oxide-based sorbents, and processes for preparing and using them are provided, wherein the sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents contain an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2 O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, containing a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  20. Durable zinc oxide-containing sorbents for coal gas desulfurization

    SciTech Connect

    Siriwardane, R.V.

    1994-12-31

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel as a matrix material, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

  1. Durable zinc oxide-containing sorbents for coal gas desulfurization

    DOEpatents

    Siriwardane, Ranjani V.

    1996-01-01

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

  2. High temperature electrolysis: zinc from zinc oxide using a solar furnace

    SciTech Connect

    MacDonald, F.J.

    1986-01-01

    Exploratory research was conducted in high temperature metal extraction using a concentrating solar furnace for process heat. Electrolysis of zinc oxide was performed using various molten salts as electrolytes; 13% AlF/sub 3//87% NaF, 45% AlF/sub 3//55% NaF, 33% ZnF/sub 2//67% NaF and NaOH. The temperature range investigated was 600 to 1400 K. Several materials were tried as crucibles and electrodes with the best being graphite for the cathode and crucible, and platinum for the anode. Experiments were performed where the zinc produced was collected and the current and voltage were measured. From this data, current efficiencies were calculated and decomposition potentials were determined.

  3. Field emission behavior of cuboid zinc oxide nanorods on zinc-filled porous silicon

    NASA Astrophysics Data System (ADS)

    Yu, Ke; Zhang, Yongsheng; Xu, Rongli; Jiang, Desheng; Luo, Laiqiang; Li, Qiong; Zhu, Ziqiang; Lu, Wei

    2005-01-01

    Single-crystalline zinc oxide (ZnO) nanorods with cuboid morphology have been prepared on the zinc-filled porous silicon substrate using a vapor phase transport method. Field-emission measurements showed that the turn-on field and threshold field of the cuboid ZnO nanorods film were about 3.2 and 8.2 V/μm respectively. From the emitter surface, a homogeneous emission image was observed with emission site density (ESD) of ˜10 4 cm -2. The better emission uniformity and the high ESD may be attributed to a large number of ZnO nanocrystallites as emitter on the surface of the nanorod end contributing to emission.

  4. High throughput growth of zinc oxide nanowires from zinc powder with the assistance of sodium chloride.

    PubMed

    Yang, Jian; Wang, Wenzhong; Ma, Yi; Wang, D Z; Steeves, D; Kimball, B; Ren, Z F

    2006-07-01

    Sodium chloride (NaCl) was found to be very helpful in producing single crystal zinc oxide (ZnO) nanowires in gram quantities. The growth involves heating the mixture of zinc powder and NaCl to 600-700 degrees C in flowing gases of oxygen and argon. A conversion efficiency of 70-80% (Zn to ZnO) was achieved when NaCl was used, and 5-10% without NaCl. The NaCl was completely removed by soaking and rinsing the mixture in water a few times. Photoluminescence spectra using excitation of 325 nm showed a very strong emission only in the visible frequency range, indicating that the surface states dominate the emission.

  5. Rare earth doped zinc oxide varistors

    DOEpatents

    McMillan, A.D.; Modine, F.A.; Lauf, R.J.; Alim, M.A.; Mahan, G.D.; Bartkowiak, M.

    1998-12-29

    A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2--4.0% oxide of at least one rare earth element, 0.5--4.0% Co{sub 3}O{sub 4}, 0.05--0.4% K{sub 2}O, 0.05--0.2% Cr{sub 2}O{sub 3}, 0--0.2% CaO, 0.00005--0.01% Al{sub 2}O{sub 3}, 0--2% MnO, 0--0.05% MgO, 0--0.5% TiO{sub 3}, 0--0.2% SnO{sub 2}, 0--0.02% B{sub 2}O{sub 3}, balance ZnO. 4 figs.

  6. Rare earth doped zinc oxide varistors

    DOEpatents

    McMillan, April D.; Modine, Frank A.; Lauf, Robert J.; Alim, Mohammad A.; Mahan, Gerald D.; Bartkowiak, Miroslaw

    1998-01-01

    A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2-4.0% oxide of at least one rare earth element, 0.5-4.0% Co.sub.3 O.sub.4, 0.05-0.4% K.sub.2 O, 0.05-0.2% Cr.sub.2 O.sub.3, 0-0.2% CaO, 0.00005-0.01% Al.sub.2 O.sub.3, 0-2% MnO, 0-0.05% MgO, 0-0.5% TiO.sub.3, 0-0.2% SnO.sub.2, 0-0.02% B.sub.2 O.sub.3, balance ZnO.

  7. Sequestration of Zinc Oxide by Fimbrial Designer Chelators

    PubMed Central

    Kjærgaard, Kristian; Sørensen, Jack K.; Schembri, Mark A.; Klemm, Per

    2000-01-01

    Type 1 fimbriae are surface organelles of Escherichia coli. By engineering a structural component of the fimbriae, FimH, to display a random peptide library, we were able to isolate metal-chelating bacteria. A library consisting of 4 × 107 independent clones was screened for binding to ZnO. Sequences responsible for ZnO adherence were identified, and distinct binding motifs were characterized. The sequences selected exhibited various degrees of affinity and specificity towards ZnO. Competitive binding experiments revealed that the sequences recognized only the oxide form of Zn. Interestingly, one of the inserts exhibited significant homology to a specific sequence in a putative zinc-containing helicase, which suggests that searches such as this one may aid in identifying binding motifs in nature. The zinc-binding bacteria might have a use in detoxification of metal-polluted water. PMID:10618196

  8. Low temperature synthesis of porous copper/zinc oxide

    SciTech Connect

    Podbrscek, Peter; Crnjak Orel, Zorica; Macek, Jadran

    2009-08-05

    A two-step urea aqueous solution process at a low temperature (90 deg. C) was employed for the preparation of a copper/zinc oxide material. Well defined porous spherical particles with average sizes of around 5 {mu}m in diameter were prepared first and then used as a support for further copper-zinc precipitation. It was found that the particle composition and shape were changed with applied stirring speed (100 rpm or 200 rpm) and that particle size is inversely proportional to the copper content in the particles. The particles preserved their size and shape after the heat treatment. Prepared Cu/ZnO samples showed catalytic activity for the reaction of steam reforming of methane. Samples were characterized by scanning field emission electron microscopy, energy dispersive X-ray analyses, X-ray powder diffraction, surface area analyses, and atomic absorption spectroscopy.

  9. A magnetic nanoparticles-zinc oxide/zinc hexacyanoferrate hybrid film for amperometric determination of tyrosine.

    PubMed

    Narang, Jagriti; Chauhan, Nidhi; Pundir, Shikha; Pundir, C S

    2013-11-01

    A method is described for the construction of a highly sensitive amperometric sensor for the detection of tyrosine, employing a magnetic nanoparticles-zinc oxide/zinc hexacyanoferrate (Fe3O4NP-ZnO/ZnHCF) hybrid film electrodeposited on the surface of a Pt electrode as working electrode. The sensor is based on electrocatalytic mechanism initiated by electrochemical oxidation of the reduced form of the hybrid film at +0.2 V vs. Ag/AgCl followed by completion of chemical oxidation of tyrosine. The sensor showed optimum response within 2 s at pH 2. The working/linear range of the sensor was 0.02-2.76 mM with a detection limit of 4 μM. The sensor measured tyrosine level in serum, a potential biomarker of phenylketonuria. The working electrode lost only 5 % of its initial activity, when stored at 4 °C, after its regular use over a period of 100 days.

  10. Highly efficient visible light mediated azo dye degradation through barium titanate decorated reduced graphene oxide sheets

    NASA Astrophysics Data System (ADS)

    Rastogi, Monisha; Kushwaha, H. S.; Vaish, Rahul

    2016-03-01

    This study investigates BaTiO3 decorated reduced graphene oxide sheets as a potential visible light active catalyst for dye degradation (Rhodamine B). The composites were prepared through conventional hydrothermal synthesis technique using hydrazine as a reducing agent. A number of techniques have been employed to affirm the morphology, composition and photocatalytic properties of the composites; these include UV-visible spectrophotoscopy that assisted in quantifying the concentration difference of Rhodamine B. The phase homogeneity of the composites was examined through x-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) was employed to confirm the orientation of the BaTiO3 particles over the reduced graphene oxide sheets. Photoluminescence (PL) emission spectra assisted in determining the surface structure and excited state of the catalyst. Fourier transformed-infrared (FTIR) spectra investigated the vibrations and adsorption peak of the composites, thereby ascertaining the formation of reduced graphene oxide. In addition, diffuse reflectance spectroscopy (DRS) demonstrated an enhanced absorption in the visible region. The experimental investigations revealed that graphene oxide acted as charge collector and simultaneously facilitated surface adsorption and photo-sensitization. It could be deduced that BaTiO3-reduced graphene oxide composites are of significant interest the field of water purification through solar photocatalysis. [Figure not available: see fulltext.

  11. 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. ...

  12. Toxicity of zinc oxide nanoparticles on adult male Wistar rats.

    PubMed

    Abbasalipourkabir, Roghayeh; Moradi, Hemen; Zarei, Sadegh; Asadi, Soheila; Salehzadeh, Aref; Ghafourikhosroshahi, Abolfazl; Mortazavi, Motahareh; Ziamajidi, Nasrin

    2015-10-01

    The purpose of this study was to investigate the effects of zinc oxide nanoparticles (nZnO) on adult male Wistar rats. Thirty male Wistar rats divided into five groups of six animals each were used for this study. For ten days, Groups one to four continuously received 50, 100, 150 and 200 mg/kg nZnO, respectively. Group five served as the control group. At the end of the study, the rats were sacrificed and histopathological study of the liver and renal tissue, sperm analysis, serum oxidative stress parameters and some liver enzymes were done. The results of this study showed that nZnO at concentration more than 50 mg/kg lead to significant changes in liver enzymes, oxidative stress, liver and renal tissue and sperm quality and quantity. In conclusion, the toxicity of nZnO is more significant when the concentration is increased; however, the use of low doses requires further investigation.

  13. The zinc ferrite obtained by oxidative precipitation method as a catalyst in n-butanol conversion

    SciTech Connect

    Klimkiewicz, Roman Wolska, Jolanta; Przepiera, Aleksander; Przepiera, Krystyna; Jablonski, Maciej; Lenart, Stanislaw

    2009-01-08

    This paper presents the results of catalytic properties of n-butanol conversion of the zinc ferrite obtained by oxidative precipitation method. The zinc ferrite showed good dehydrogenating activity but also catalyzed consecutive bimolecular condensation of emerged aldehyde particles into symmetrical ketone. The zinc-iron oxide of spinel structure was prepared from ferrous sulfate, which forms as a waste during the titanium dioxide production. The X-ray diffraction methods (XRD, XRF) were used in determining the structure and composition of obtained zinc ferrite, while thermogravimetry (TG-DTG), and differential thermal analysis (DTA) were used in the study of thermal transformations of zinc spinel in air.

  14. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    PubMed

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site.

  15. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    PubMed

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site. PMID:27131753

  16. Behavior of zinc oxide surge arresters under pollution

    SciTech Connect

    Feser, F.; Kohler, W.; Qiu, D. ); Chrzan, K. )

    1991-04-01

    This paper presents results of pollution tests with AC voltages which were carried out with a multi-unit zinc oxide arrester. The interaction between the polluted porcelain housing and the inner varistor column due to capacitive coupling has been found to be responsible for the temperature rise of varistor elements. The different voltage distribution between inside and outside of the arrester also causes a high radial electric field which can lead to internal discharges if the radial insulation system is not properly designed. These internal discharges may damage varistor elements which are not adequately coated and may cause a total destruction of the arrester.

  17. Antireflective nanostructured zinc oxide arrays produced by pulsed electrodeposition

    SciTech Connect

    Klochko, N. P. Klepikova, K. S.; Khrypunov, G. S.; Volkova, N. D.; Kopach, V. R.; Lyubov, V. M.; Kirichenko, M. V.; Kopach, A. V.

    2015-02-15

    Conditions for the pulsed electrochemical deposition of nanostructured zinc oxide arrays with a certain morphology, crystal structure, and optical properties from aqueous electrolytes onto substrates of transparent electrically conducting tin dioxide and on single-crystal silicon wafers with built-in homojunctions are studied in order to develop antireflection coatings for solar cells. It is shown that it is possible to obtain single-layer planar antireflection coatings or arrays of nanorods of this material, both having the form of hexagonal prisms and exhibiting the moth-eye effect.

  18. Interfacial mixing during annealing of zinc oxide nanoparticle junctions

    NASA Astrophysics Data System (ADS)

    Hu, Ming; Giapis, Konstantinos P.; Poulikakos, Dimos

    2011-05-01

    The process of forming a junction between crystalline zinc oxide (ZnO) nanoparticles during pulsed thermal annealing in liquid tetradecane is studied using molecular dynamics simulation. Pairs of equal and unequal size particles are considered with emphasis on neck growth and atom mixing. The contact area and interface width of the junction are found to increase with heat pulse power albeit at different rates. The results suggest that it is possible to increase the junction area without significant mixing of atoms across the junction interface by tailoring the heat pulse power.

  19. Structural characterization of impurified zinc oxide thin films

    SciTech Connect

    Trinca, L. M.; Galca, A. C. Stancu, V. Chirila, C. Pintilie, L.

    2014-11-05

    Europium doped zinc oxide (Eu:ZnO) thin films have been obtained by pulsed laser deposition (PLD). 002 textured thin films were achieved on glass and silicon substrates, while hetero-epilayers and homo-epilayers have been attained on single crystal SrTiO{sub 3} and ZnO, respectively. X-ray Diffraction (XRD) was employed to characterize the Eu:ZnO thin films. Extended XRD studies confirmed the different thin film structural properties as function of chosen substrates.

  20. Zinc oxide nanowires and nanorods fabricated by vapour-phase transport at low temperature

    NASA Astrophysics Data System (ADS)

    Xu, C. X.; Sun, X. W.; Dong, Z. L.; Yu, M. B.; My, T. D.; Zhang, X. H.; Chua, S. J.; White, T. J.

    2004-07-01

    Using zinc chloride as source material, zinc oxide nanowires and nanorods were fabricated by a vapour-phase transport method at low temperature. The nanowires grown on gold-coated silicon showed a uniform diameter of about 40 nm, and the nanorods on copper-coated silicon grew upwards to form flower-like arrays. The x-ray diffraction and transmission electron microscopy analyses demonstrated that the nanostructural zinc oxide grew along the [0001] direction. The growth process was attributed to a vapour-liquid-solid mechanism. Distinct photoluminescent behaviours were observed for zinc oxide nanostructures grown on gold-coated and copper-coated silicon wafers.

  1. 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.

  2. Electrochemical deposition of zinc oxide nanorods for hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Torres Damasco Ty, Jennifer; Yanagi, Hisao

    2015-04-01

    Zinc oxide (ZnO) nanorod arrays for inorganic/organic hybrid solar cells were electrochemically deposited on indium tin oxide (ITO) substrates with a rotating disk electrode setup. The addition of a ZnO seed layer on the ITO prior to electrochemical deposition improved the morphology of the nanorods, resulting in nanorods with smaller and homogenous diameters as well as a higher degree of vertical orientation on to the substrate. The ZnO films deposited on the seeded ITO substrates had higher optical transmittance and lower concentration of defects. Chronoamperometric transient curves show that nucleation and coalescence occurred later for bare ITO substrates, indicating lower densities of initial nuclei, resulting in the growth of nanorods with larger diameters. The solar cell characteristics of the devices fabricated from the seeded ITO substrates were better. The seed layer also acts as a hole-blocking layer, preventing the direct contact between the hole-transporting polymer material and the ITO.

  3. Design and photocatalytic activity of nanosized zinc oxides

    NASA Astrophysics Data System (ADS)

    Gancheva, M.; Markova-Velichkova, M.; Atanasova, G.; Kovacheva, D.; Uzunov, I.; Cukeva, R.

    2016-04-01

    Zinc oxide particles with various morphologies were successfully prepared via three synthesis methods: precipitation; tribophysical treatment and sonochemistry. The as-synthesized samples were characterized by X-ray diffraction (XRD); infrared spectroscopy (IR); scanning electron microscope (SEM); BET specific surface area; electron-paramagnetic resonance (EPR), UV-Vis absorption/diffuse reflectance and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities of the samples were evaluated by degradation of Malachite Green (MG) in an aqueous solution under UV and visible irradiation. The obtained ZnO powders possess crystallites size below 20 nm. The ZnO with spherical particles were obtained by precipitation method. The sonochemistry approach leads to preparation of ZnO with nanorod particles. The calculated band gaps of various ZnO powders belong to the range from 3.12 to 3.30 eV. The obtained polycrystalline zinc oxides exhibit good photocatalytic activity which is strongly influenced by the preparation conditions. The nanorod ZnO exhibits high photocatalytic activity under UV irradiation which is attributed to the morphology and the geometric surface of the particles. The ZnO obtained by precipitation has better photocatalytic efficiency under visible irradiation due to high B.E.T. specific surface area and the low level of band gap. Tribophysical treatment of a particle size-homogeneous system leads to deterioration of the photocatalytic activity of the material.

  4. 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.

  5. Zinc oxide nanoparticles as novel alpha-amylase inhibitors

    NASA Astrophysics Data System (ADS)

    Dhobale, Sandip; Thite, Trupti; Laware, S. L.; Rode, C. V.; Koppikar, Soumya J.; Ghanekar, Ruchika-Kaul; Kale, S. N.

    2008-11-01

    Amylase inhibitors, also known as starch blockers, contain substances that prevent dietary starches from being absorbed by the body via inhibiting breakdown of complex sugars to simpler ones. In this sense, these materials are projected as having potential applications in diabetes control. In this context, we report on zinc oxide nanoparticles as possible alpha-amylase inhibitors. Zinc oxide nanoparticles have been synthesized using soft-chemistry approach and 1-thioglycerol was used as a surfactant to yield polycrystalline nanoparticles of size ˜18 nm, stabilized in wurtzite structure. Conjugation study and structural characterization have been done using x-ray diffraction technique, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and transmission electron microscopy. Cytotoxicity studies on human fibrosarcoma (HT-1080) and skin carcinoma (A-431) cell lines as well as mouse primary fibroblast cells demonstrate that up to a dose of 20 μg/ml, ZnO nanoparticles are nontoxic to the cells. We report for the first time the alpha-amylase inhibitory activity of ZnO nanoparticles wherein an optimum dose of 20 μg/ml was sufficient to exhibit 49% glucose inhibition at neutral pH and 35 °C temperature. This inhibitory activity was similar to that obtained with acarbose (a standard alpha-amylase inhibitor), thereby projecting ZnO nanoparticles as novel alpha-amylase inhibitors.

  6. Growth of zinc oxide nanorods, tetrapods, and nanobelts without catalyst.

    PubMed

    Fouad, O A

    2006-07-01

    Zinc oxide (ZnO) nanostructures with various morphologies have been synthesized without catalyst in a one-step simple redox process. The results show that ZnO nanorods, nanobelts, and tetrapods with hexagonal needled arms could be synthesized via thermal treatment of a mixture of zinc oxide and charcoal powder in a muffle furnace at 1000-1200 degrees C for 240 min. XRD analyses showed that polycrystalline ZnO phase with wurtzite crystal structure was formed. At a relatively low temperature, 1000 degrees C, the ZnO structure was found to be a bundle of denser nanorods. By increasing the reaction temperature to 1100 degrees C, tetrapod-like structures of needle-like arms with pyramidal tips were formed. With the increase of temperature up to 1200 degrees C, the morphology of ZnO nanostructures changed from nanorods and tetrapods to coalescence grains. Reaction temperature was found to be the most important experimental parameter that played an important role in controlling the mode, mechanism of growth, and formation of different ZnO morphologies. PMID:17025131

  7. Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc

    EPA Science Inventory

    Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

  8. Effect of Process Parameters on the Size and Shape of Nano- and Micrometric Zinc Oxide.

    PubMed

    Pulit-Prociak, Jolanta; Banach, Marcin

    2016-01-01

    The paper presents a method of obtaining zinc oxide nano- and microparticles. In these studies microwave reactor and laboratory pressure reactor were used. Since microwave radiation accelerates proceeding of reactions, this way was found to be an effective method in the process of obtaining nanocrystallines of zinc oxide. The size of prepared particles rarely exceeded 500 nm. PMID:27333554

  9. Azo dye removal in a membrane-free up-flow biocatalyzed electrolysis reactor coupled with an aerobic bio-contact oxidation reactor.

    PubMed

    Cui, Dan; Guo, Yu-Qi; Cheng, Hao-Yi; Liang, Bin; Kong, Fan-Ying; Lee, Hyung-Sool; Wang, Ai-Jie

    2012-11-15

    Azo dyes that consist of a large quantity of dye wastewater are toxic and persistent to biodegradation, while they should be removed before being discharged to water body. In this study, Alizarin Yellow R (AYR) as a model azo dye was decolorized in a combined bio-system of membrane-free, continuous up-flow bio-catalyzed electrolysis reactor (UBER) and subsequent aerobic bio-contact oxidation reactor (ABOR). With the supply of external power source 0.5 V in the UBER, AYR decolorization efficiency increased up to 94.8±1.5%. Products formation efficiencies of p-phenylenediamine (PPD) and 5-aminosalicylic acid (5-ASA) were above 90% and 60%, respectively. Electron recovery efficiency based on AYR removal in cathode zone was nearly 100% at HRTs longer than 6 h. Relatively high concentration of AYR accumulated at higher AYR loading rates (>780 gm(-3) d(-1)) likely inhibited acetate oxidation of anode-respiring bacteria on the anode, which decreased current density in the UBER; optimal AYR loading rate for the UBER was 680 gm(-3) d(-1) (HRT 2.5 h). The subsequent ABOR further improved effluent quality. Overall the Chroma decreased from 320 times to 80 times in the combined bio-system to meet the textile wastewater discharge standard II in China. PMID:23009797

  10. Nearly full-dense and fine-grained AZO:Y ceramics sintered from the corresponding nanoparticles

    PubMed Central

    2012-01-01

    Aluminum-doped zinc oxide ceramics with yttria doping (AZO:Y) ranging from 0 to 0.2 wt.% were fabricated by pressureless sintering yttria-modified nanoparticles in air at 1,300°C. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, a physical property measurement system, and a densimeter were employed to characterize the precursor nanoparticles and the sintered AZO ceramics. It was shown that a small amount of yttria doping can remarkably retard the growth of the as-received precursor nanoparticles, further improve the microstructure, refine the grain size, and enhance the density for the sintered ceramic. Increasing the yttria doping to 0.2 wt.%, the AZO:Y nanoparticles synthetized by a coprecipitation process have a nearly sphere-shaped morphology and a mean particle diameter of 15.1 nm. Using the same amount of yttria, a fully dense AZO ceramic (99.98% of theoretical density) with a grain size of 2.2 μm and a bulk resistivity of 4.6 × 10−3 Ω·cm can be achieved. This kind of AZO:Y ceramic has a potential to be used as a high-quality sputtering target to deposit ZnO-based transparent conductive films with better optical and electrical properties. PMID:22929049

  11. Myeloperoxidase-derived oxidants rapidly oxidize and disrupt zinc-cysteine/histidine clusters in proteins.

    PubMed

    Cook, Naomi L; Pattison, David I; Davies, Michael J

    2012-12-01

    Zinc is an abundant cellular transition metal ion, which binds avidly to protein cysteine (Cys) and histidine (His) residues to form zinc-Cys/His clusters; these play a key role in the function of many proteins (e.g., DNA binding and repair enzymes, transcription factors, nitric oxide synthase). Leukocyte-derived myeloperoxidase generates powerful oxidants including hypochlorous (HOCl), hypobromous (HOBr), and hypothiocyanous (HOSCN) acids from H(2)O(2) and (pseudo)halide ions. Excessive or misplaced formation of these species is associated with cellular dysfunction, apoptosis and necrosis, and multiple inflammatory diseases. HOCl and HOBr react rapidly with sulfur-containing compounds, and HOSCN reacts specifically with thiols. Consequently, we hypothesized that zinc-Cys/His clusters would be targets for these oxidants, and the activity of such enzymes would be perturbed. This hypothesis has been tested using yeast alcohol dehydrogenase (YADH), which contains a well-characterized Zn(1)Cys(2)His(1) cluster. Incubation of YADH with pathologically relevant concentrations of HOSCN, HOCl, and HOBr resulted in rapid oxidation of the protein (rate constants, determined by competition kinetics, for reaction of HOCl and HOSCN with YADH being (3.3±0.9)×10(8) and (2.9±0.4)×10(4) M(-1) s(-1) per YADH monomer, respectively), loss of enzyme activity, Zn(2+) release, changes in protein structure (particularly formation of disulfide cross-links), and oxidation of Cys residues. The loss of enzyme activity correlated with Zn(2+) release, loss of thiols, and changes in protein structure. We conclude that exposure of zinc-Cys/His clusters to inflammatory oxidants can result in impaired protein activity, thiol oxidation, and Zn(2+) release. These reactions may contribute to inflammation-induced tissue damage.

  12. Myeloperoxidase-derived oxidants rapidly oxidize and disrupt zinc-cysteine/histidine clusters in proteins.

    PubMed

    Cook, Naomi L; Pattison, David I; Davies, Michael J

    2012-12-01

    Zinc is an abundant cellular transition metal ion, which binds avidly to protein cysteine (Cys) and histidine (His) residues to form zinc-Cys/His clusters; these play a key role in the function of many proteins (e.g., DNA binding and repair enzymes, transcription factors, nitric oxide synthase). Leukocyte-derived myeloperoxidase generates powerful oxidants including hypochlorous (HOCl), hypobromous (HOBr), and hypothiocyanous (HOSCN) acids from H(2)O(2) and (pseudo)halide ions. Excessive or misplaced formation of these species is associated with cellular dysfunction, apoptosis and necrosis, and multiple inflammatory diseases. HOCl and HOBr react rapidly with sulfur-containing compounds, and HOSCN reacts specifically with thiols. Consequently, we hypothesized that zinc-Cys/His clusters would be targets for these oxidants, and the activity of such enzymes would be perturbed. This hypothesis has been tested using yeast alcohol dehydrogenase (YADH), which contains a well-characterized Zn(1)Cys(2)His(1) cluster. Incubation of YADH with pathologically relevant concentrations of HOSCN, HOCl, and HOBr resulted in rapid oxidation of the protein (rate constants, determined by competition kinetics, for reaction of HOCl and HOSCN with YADH being (3.3±0.9)×10(8) and (2.9±0.4)×10(4) M(-1) s(-1) per YADH monomer, respectively), loss of enzyme activity, Zn(2+) release, changes in protein structure (particularly formation of disulfide cross-links), and oxidation of Cys residues. The loss of enzyme activity correlated with Zn(2+) release, loss of thiols, and changes in protein structure. We conclude that exposure of zinc-Cys/His clusters to inflammatory oxidants can result in impaired protein activity, thiol oxidation, and Zn(2+) release. These reactions may contribute to inflammation-induced tissue damage. PMID:23032100

  13. Low temperature near infrared plasmonic gas sensing of gallium and aluminum doped zinc oxide thin films from colloidal inks (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Sturaro, Marco; Della Gaspera, Enrico; Martucci, Alessandro; Guglielmi, Massimo

    2015-08-01

    We obtained Gallium-doped and Aluminum-doped Zinc Oxide nanocrystals by non aqueous colloidal heat-up synthesis. These nanocrystals are transparent in the visible range but exhibit localized surface plasmon resonances (LSPRs) in the near IR range, tunable and shiftable with dopant concentration (up to 20% mol nominal). GZO and AZO inks can be deposited by spin coating, dip coating or spray coating on glass or silicon, leading to uniform and high optical quality thin films. To enhance absorbtion in the infrared region, samples can be annealed in inert or reductant atmosphere (N2/Argon or H2 in Argon) resulting in plasmon intensity enhancement due to oxygen vacancies and conduction band electrons density increment. Then IR plasmon has been exploited for gas sensing application, according to the plasmon shifting for carrier density variations, due to electrons injection or removal by the target gas/sample chemical interactions. To obtain a functional sensor at low temperature, another treatment was investigated, involving surfanctant removal by dipping deposited films in a solution of organic acid, tipically oxalic acid in acetonitrile; such process could pave the way to obtain similar sensors deposited on plastics. Finally, GZO and AZO thin films proved sensibility to H2 and NOx, and in particular circumstances also to CO, from room temperature to 200°C. Sensibility behavior for different dopant concentration and temperture was investigated both in IR plasmon wavelengths (~2400 nm) and zinc oxide band gap (~370 nm). An enhancement in sensitivity to H2 is obtained by adding Pt nanoparticles, exploiting catalytic properties of Platinum for hydrogen splitting.

  14. Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery

    NASA Astrophysics Data System (ADS)

    Hou, Lin; Shi, Yuyang; Jiang, Guixiang; Liu, Wei; Han, Huili; Feng, Qianhua; Ren, Junxiao; Yuan, Yujie; Wang, Yongchao; Shi, Jinjin; Zhang, Zhenzhong

    2016-08-01

    A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO–N=N–GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO–N=N–GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO–N=N–GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

  15. Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery

    NASA Astrophysics Data System (ADS)

    Hou, Lin; Shi, Yuyang; Jiang, Guixiang; Liu, Wei; Han, Huili; Feng, Qianhua; Ren, Junxiao; Yuan, Yujie; Wang, Yongchao; Shi, Jinjin; Zhang, Zhenzhong

    2016-08-01

    A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO-N=N-GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO-N=N-GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO-N=N-GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

  16. Size-dependent electrical conductivity of indium zinc oxide deposited by RF magnetron sputtering.

    PubMed

    Heo, Young-Woo; Pearton, S J; Norton, D P

    2012-04-01

    We investigated the size-dependent electrical conductivities of indium zinc oxide stripes with different widths from 50 nm to 4 microm and with the same thickness of 50 nm deposited by RF magnetron sputtering. The size of the indium zinc oxide stripes was controlled by e-beam lithography. The distance of the two Ti/Au Ohmic electrodes along the indium zinc oxide stripes was kept constant at 25 microm. The electrical conductivity decreased as the size of the indium zinc oxide stripes decreased below a critical width (80 nm). The activation energy, derived from the electric conductivity versus temperature measurement, was dependent on the dimensions of indium zinc oxide stripes. These results can be understood as stemming from surface charge trapping from the absorption of oxygen and/or water vapor, which leads to an increase in the energy difference between the conduction energy band and the Fermi energy. PMID:22849102

  17. An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium

    PubMed Central

    2013-01-01

    Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets. PMID:24011201

  18. Characteristics of low-resistivity aluminum-doped zinc oxide films deposited at room temperature by off-axis radio-frequency sputtering on flexible plastic substrates

    NASA Astrophysics Data System (ADS)

    Wang, Li-Min; Wang, Chih-Yi; Jheng, Ciao-Ren; Wu, Syu-Jhan; Sai, Chen-Kai; Lee, Ya-Ju; Chiang, Ching-Yu; Shew, Bor-Yuan

    2016-08-01

    The crystalline structure, morphology, composition, electrical transport, and optical properties of aluminum-doped zinc oxide (AZO) films are studied for applications in transparent electronics and optoelectronic devices. AZO thin films of c-axis-oriented growth and with different thickness were deposited on PET flexible plastic substrates at room temperature by rf magnetron sputtering. A larger grain size with a decreased strain ɛ value is observed in a thicker film, while changes in composition for films with different thicknesses are insignificant. Moreover, the resistivity of film decreases with increasing thickness, and the low-temperature electrical transport properties can be described by the scenario of quantum corrections to conductivity. With the room-temperature growth conditions, the resistivity of 4.5 × 10-4 Ω cm, carrier concentration of 6.4 × 1020 cm-3, and transmittance of 80 % for the 1100-nm-thick film are obtained. In addition, the optical bandgap energy decreases with increasing film thickness, which can be attributed to the bandgap renormalization and crystallite size effects.

  19. Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Salgaonkar, Bhakti B.; Das, Deepthi; Bragança, Judith Maria

    2016-02-01

    Industrialization as well as other anthropogenic activities have resulted in addition of high loads of metal and/or metal nanoparticles to the environment. In this study, the effect of one of the widely used heavy metal, zinc (Zn) and zinc oxide nanoparticles (ZnO NPs) on extremely halophilic archaea was evaluated. One representative member from four genera namely Halococcus, Haloferax, Halorubrum and Haloarcula of the family Halobacteriaceae was taken as the model organism. All the haloarchaeal genera investigated were resistant to both ZnCl2 and ZnO NPs at varying concentrations. Halococcus strain BK6 and Haloferax strain BBK2 showed the highest resistance in complex/minimal medium of up to 2.0/1.0 mM ZnCl2 and 2.0/1.0-0.5 mM ZnO NP. Accumulation of ZnCl2/ZnO NPs was seen as Haloferax strain BBK2 (287.2/549.6 mg g-1) > Halococcus strain BK6 (165.9/388.5 mg g-1) > Haloarcula strain BS2 (93.2/28.5 mg g-1) > Halorubrum strain BS17 (29.9/16.2 mg g-1). Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis revealed that bulk ZnCl2 was sorbed at a higher concentration (21.77 %) on the cell surface of Haloferax strain BBK2 as compared to the ZnO NPs (14.89 %).

  20. 1-Dimensional Zinc Oxide Nanomaterial Growth and Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Choi, Hyung Woo

    Zinc oxide (ZnO) has attracted much interest during last decades as a functional material. Furthermore, ZnO is a potential material for transparent conducting oxide material competing with indium tin oxide (ITO), graphene, and carbon nanotube film. It has been known as a conductive material when doped with elements such as indium, gallium and aluminum. The solubility of those dopant elements in ZnO is still debatable; but, it is necessary to find alternative conducting materials when their form is film or nanostructure for display devices. This is a consequence of the ever increasing price of indium. In addition, a new generation solar cell (nanostructured or hybrid photovoltaics) requires compatible materials which are capable of free standing on substrates without seed or buffer layers and have the ability introduce electrons or holes pathway without blocking towards electrodes. The nanostructures for solar cells using inorganic materials such as silicon (Si), titanium oxide (TiO2), and ZnO have been an interesting topic for research in solar cell community in order to overcome the limitation of efficiency for organic solar cells. This dissertation is a study of the rational solution-based synthesis of 1-dimentional ZnO nanomaterial and its solar cell applications. These results have implications in cost effective and uniform nanomanufacturing for the next generation solar cells application by controlling growth condition and by doping transition metal element in solution.

  1. Zinc oxide and related compounds: order within the disorder

    NASA Astrophysics Data System (ADS)

    Martins, R.; Pereira, Luisa; Barquinha, P.; Ferreira, I.; Prabakaran, R.; Goncalves, G.; Goncalves, A.; Fortunato, E.

    2009-02-01

    This paper discusses the effect of order and disorder on the electrical and optical performance of ionic oxide semiconductors based on zinc oxide. These materials are used as active thin films in electronic devices such as pn heterojunction solar cells and thin-film transistors. Considering the expected conduction mechanism in ordered and disordered semiconductors the role of the spherical symmetry of the s electron conduction bands will be analyzed and compared to covalent semiconductors. The obtained results show p-type c-Si/a-IZO/poly-ZGO solar cells exhibiting efficiencies above 14%, in device areas of about 2.34 cm2. Amorphous oxide TFTs based on the Ga-Zn-Sn-O system demonstrate superior performance than the polycrystalline TFTs based on ZnO, translated by ION/IOFF ratio exceeding 107, turn-on voltage below 1-2 V and saturation mobility above 25 cm2/Vs. Apart from that, preliminary data on p-type oxide TFT based on the Zn-Cu-O system will also be presented.

  2. Zinc oxide nanoparticles induce eosinophilic airway inflammation in mice.

    PubMed

    Huang, Kuo-Liang; Lee, Yi-Hsin; Chen, Hau-Inh; Liao, Huang-Shen; Chiang, Bor-Luen; Cheng, Tsun-Jen

    2015-10-30

    Zinc oxide nanoparticles (ZnO NPs) have been widely used in industry. The metal composition of PM2.5 might contribute to the higher prevalence of asthma. To investigate the effects of ZnO NPs on allergic airway inflammation, mice were first exposed to different concentrations of ZnO NPs (0.1 mg/kg, 0.5 mg/kg) or to a combination of ZnO NPs and chicken egg ovalbumin (OVA) by oropharyngeal aspiration on day 0 and day 7 and then were sacrificed 5 days later. The subsequent time course of airway inflammation in the mice after ZnO NPs exposure was evaluated on days 1, 7, and 14. To further determine the role of zinc ions, ZnCl2 was also administered. The inflammatory cell count, cytokine levels in the bronchoalveolar lavage fluid (BALF), and lung histopathology were examined. We found significant neutrophilia after exposure to high-dose ZnO NPs on day 1 and significant eosinophilia in the BALF at 7 days. However, the expression levels of the T helper 2 (Th2) cytokines IL-4, IL-5, and IL-13 increased significantly after 24h of exposure to only ZnO NPs and then decreased gradually. These results suggested that ZnO NPs could cause eosinophilic airway inflammation in the absence of allergens.

  3. a Comprehensive DFT Study of Zinc Oxide in Different Phases

    NASA Astrophysics Data System (ADS)

    Ul Haq, Bakhtiar; Afaq, A.; Ahmed, R.; Naseem, S.

    2012-06-01

    A density functional study for structural and electronic properties of Zinc Oxide (ZnO), in wurtzite, rock salt and zinc-blende phases has been performed using full potential-linearized augmented plane wave/linearized augmented plane wave plus local ideal orbital (FP-LAPW/L(APW+lo) approach as realized in WIEN2k code. To approximate exchange correlation energy and corresponding potential, a special GGA parameterized by Wu-Cohen has been implemented. Our results of lattice constants, bulk moduli as well as for internal parameter with GGA-WC are found to be more reliable. This study reveals that value of internal parameter decreases with increasing volume whereas computed electronic band structure confirms the direct band gap behavior of ZnO in B4 and B3 phases while indirect band gap behavior in B1 phase. Moreover, two fold degeneracy at the maxima of valence band for B4 and B1 phases whereas three fold for B3 is observed. A detailed comparison with experimental and other first principles studies is also made.

  4. 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.

  5. Optimization and modelling of synthetic azo dye wastewater treatment using Graphene oxide nanoplatelets: Characterization toxicity evaluation and optimization using Artificial Neural Network.

    PubMed

    Banerjee, Priya; Sau, Shubhra; Das, Papita; Mukhopadhayay, Aniruddha

    2015-09-01

    Azo dyes pose a major threat to current civilization by appearing in almost all streams of wastewater. The present investigation was carried out to examine the potential of Graphene oxide (GO) nanoplatelets as an efficient, cost-effective and non-toxic azo dye adsorbent for efficient wastewater treatment. The treatment process was optimized using Artificial Neural Network for maximum percentage dye removal and evaluated in terms of varying operational parameters, process kinetics and thermodynamics. A brief toxicity assay was also designed using fresh water snail Bellamya benghalensis to analyze the quality of the treated solution. 97.78% removal of safranin dye was obtained using GO as adsorbent. Characterization of GO nanoplatelets (using SEM, TEM, AFM and FTIR) reported the changes in its structure as well as surface morphology before and after use and explained its prospective as a good and environmentally benign adsorbent in very low quantities. The data recorded when subjected to different isotherms best fitted the Temkin isotherm. Further analysis revealed the process to be endothermic and chemisorption in nature. The verdict of the toxicity assay rendered the treated permeate as biologically safe for discharge or reuse in industrial and domestic purposes. PMID:25966335

  6. 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

  7. Interpretation of optical conductivity of zinc oxide nanowires

    SciTech Connect

    Choudhary, K. K.; Kaurav, N.

    2015-07-31

    The frequency dependent optical response of Zinc Oxide (ZnO) nanowires is theoretically analyzed within the two component schemes: one is the motion of coherent Drude electrons within the ZnO nanowire and the other is incoherent motion of electrons from one nanowire to other. The model has only one free parameter, the relaxation rate. The frequency dependent relaxation rates are expressed in terms of memory functions. The coherent Drude carriers form a sharp peak at zero frequency and a long tail at higher frequencies, i.e. in the infrared region. However, the hopping of carriers from one nanowire to other (incoherent motion of electrons) yields a peak value in the optical conductivity around mid infrared region. It is found that both the Drude and hopping carriers will contribute to the optical process of conduction in ZnO nanowire.

  8. Nanosized zinc oxide particles induce neural stem cell apoptosis

    NASA Astrophysics Data System (ADS)

    Deng, Xiaoyong; Luan, Qixia; Chen, Wenting; Wang, Yanli; Wu, Minghong; Zhang, Haijiao; Jiao, Zheng

    2009-03-01

    Given the intensive application of nanoscale zinc oxide (ZnO) materials in our life, growing concerns have arisen about its unintentional health and environmental impacts. In this study, the neurotoxicity of different sized ZnO nanoparticles in mouse neural stem cells (NSCs) was investigated. A cell viability assay indicated that ZnO nanoparticles manifested dose-dependent, but no size-dependent toxic effects on NSCs. Apoptotic cells were observed and analyzed by confocal microscopy, transmission electron microscopy examination, and flow cytometry. All the results support the viewpoint that the ZnO nanoparticle toxicity comes from the dissolved Zn2+ in the culture medium or inside cells. Our results highlight the need for caution during the use and disposal of ZnO manufactured nanomaterials to prevent the unintended environmental and health impacts.

  9. Gold coated zinc oxide nanonecklaces as a SERS substrate.

    PubMed

    He, Lili; Shi, Jian; Sun, Xin; Lin, Mengshi; Yu, Ping; Li, Hao

    2011-04-01

    Faceted zinc oxide nanonecklace (ZnO NN) arrays were grown on r-plane sapphires along one direction (ZnO [0001] II sapphire [10-11] and ZnO (-12-10) II sapphire (01-12)) using chemical vapor deposition. After coated with 45 nm gold films and annealed at 250 degrees C for 30 seconds, the coated ZnO NNs exhibit satisfactory and stable surface enhanced Raman scattering (SERS) effects when tested with melamine and other chemicals. The limit of detection of melamine is 10(-5) mol/L and the analytical enhancement factor is 10(4), which is competitive to a commercial substrate. This study indicates that gold coated ZnO NN substrates have a great potential as SERS-active substrates in rapid detection of trace amount food contaminants such as melamine and other chemicals. PMID:21776731

  10. Gas sensing performance of nano zinc oxide sensors

    NASA Astrophysics Data System (ADS)

    Sharma, Shiva; Chauhan, Pratima

    2016-04-01

    We report nano Zinc Oxide (ZnO) synthesized by sol-gel method possessing the crystallite size which varies from 25.17 nm to 47.27 nm. The Scanning electron microscope (SEM) image confirms the uniform distribution of nanograins with high porosity. The Energy dispersion X-ray (EDAX) spectrum gives the atomic composition of Zn and O in ZnO powders and confirms the formation of nano ZnO particles. These factors reveals that Nano ZnO based gas sensors are highly sensitive to Ammonia gas (NH3) at room temperature, indicating the maximum response 86.8% at 800 ppm with fast response time and recovery time of 36 sec and 23 sec respectively.

  11. Functionalization of textiles with silver and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pulit-Prociak, Jolanta; Chwastowski, Jarosław; Kucharski, Arkadiusz; Banach, Marcin

    2016-11-01

    The paper presents a method for functionalization of textile materials using fabric dyes modified with silver or zinc oxide nanoparticles. Embedding of these nanoparticles into the structure of other materials makes that the final product is characterized by antimicrobial properties. Indigo and commercially available dye were involved in studies. It is worth to note that silver nanoparticles were obtained in-situ in the reaction of preparing indigo dye and in the process of preparing commercial dye baths. Such a method allows reducing technological steps. The modified dyes were used for dyeing of cotton fibers. The antimicrobial properties of final textile materials were studied. Saccharomyces cerevisiae strain was used in microbiological test. The results confirmed biocidal activity of prepared materials.

  12. Green Approach for Fabrication and Applications of Zinc Oxide Nanoparticles

    PubMed Central

    Smita, Kumari; Cumbal, Luis

    2014-01-01

    Zinc oxide nanoparticles (ZnO-NPs) are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi) peel extract with particle size ranging from 12 to 72 nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10 mg/L, 6 h) against methylene blue and antioxidant efficacy (≥80% for 1.2 mM) against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns. PMID:25374484

  13. Gold coated zinc oxide nanonecklaces as a SERS substrate.

    PubMed

    He, Lili; Shi, Jian; Sun, Xin; Lin, Mengshi; Yu, Ping; Li, Hao

    2011-04-01

    Faceted zinc oxide nanonecklace (ZnO NN) arrays were grown on r-plane sapphires along one direction (ZnO [0001] II sapphire [10-11] and ZnO (-12-10) II sapphire (01-12)) using chemical vapor deposition. After coated with 45 nm gold films and annealed at 250 degrees C for 30 seconds, the coated ZnO NNs exhibit satisfactory and stable surface enhanced Raman scattering (SERS) effects when tested with melamine and other chemicals. The limit of detection of melamine is 10(-5) mol/L and the analytical enhancement factor is 10(4), which is competitive to a commercial substrate. This study indicates that gold coated ZnO NN substrates have a great potential as SERS-active substrates in rapid detection of trace amount food contaminants such as melamine and other chemicals.

  14. Zinc oxide- and polymer-based composite varistors

    NASA Astrophysics Data System (ADS)

    Hashimov, A. M.; Hasanli, Sh. M.; Mehtizadeh, R. N.; Bayramov, Kh. B.; Azizova, Sh. M.

    2006-09-01

    This work reports on homogeneous varistor ceramics prepared from a mixture of impurity-doped zinc oxide (C) [E. Suzuki et al., IEEE Trans. Electron Dev. 47, 354 (2000); F.L. Souza et al., Mater. Chem. Phys. 80, 512 (2003)] and nonpolar polyethylene (PE) using a hot pressing method. The content of the composite components was varied from 10% (90%) to 70% (30%) of C (PE) and the thickness of the samples obtained was 40 or 150 m. The voltage-current characteristics and electroconductivity with applied voltage were measured for all the samples obtained at room temperature. Also, the same samples were tested using infrared absorption and X-ray diffraction methods. As a result of these studies, the influence of ceramic composition on the ceramic parameters was established.

  15. Adsorption of isopropanol and cyclohexane on zinc oxide

    NASA Astrophysics Data System (ADS)

    Bratchikova, I. G.; Pylinina, A. I.; Platonov, E. A.; Danilova, M. N.; Isaeva, N. Yu.; Yagodovskii, V. D.

    2015-01-01

    Adsorption isotherms of isopropanol and cyclohexane are obtained in the range of 234-303 K on an initial surface of zinc oxide and after its treatment with glow-discharge plasma in O2 and high-frequency plasma in Ar. The values of isosteric heat and adsorption entropy are shown to be only slightly affected by these treatments. It is found that the acidity of the surface increases by 38 and 97%, respectively, and the acidic sites are not adsorption sites for either adsorbate. At low degrees of occupation, the adsorption isotherms of (CH3)2CHOH are described by an equation of induced adsorption whose parameters are dependent on the plasma-chemical treatments. It is concluded that adsorbed isopropanol particles exist in positively and negatively charged forms. The adsorption of cyclohexane is described by the Hill-de Boer equation for the initial ZnO surface, and by the Langmuir equation after plasma-chemical treatments.

  16. Zinc as a micronutrient and its preventive role of oxidative damage in cells.

    PubMed

    Kloubert, Veronika; Rink, Lothar

    2015-10-01

    Zinc is an essential trace element with special importance in the immune system. Deficiencies of zinc are seen in the course of ageing and in various diseases, such as diabetes mellitus or rheumathoid arthritis. The trace element is essential for a variety of basic cellular functions and especially important for various enzymes participating in the production and neutralization of reactive oxygen species (ROS) which are normally produced by the cell. Under normal conditions ROS are neutralized and are not able to harm the cell, but in case of ROS elevation, oxidative damage within the cell is the result. Interestingly, zinc deficiency is directly associated with oxidative stress. Thus, control and regulation of the intracellular zinc content is essential with participation of various transporter and zinc-binding proteins, such as metallothionein. Oxidative stress is mainly caused by elevated ROS production and a decrease of antioxidant mechanisms. Zinc partly functions as an antioxidant although it is redox inert. Zinc supplementation is associated with decreased ROS formation exhibiting beneficial effects especially in ageing and diabetes mellitus. This review summarizes current findings concerning zinc as a micronutrient and its actions as a pro-antioxidant, and the association between zinc and oxidative stress under various conditions is highlighted. PMID:26286461

  17. Zinc oxide tetrapods as efficient photocatalysts for organic pollutant degradation

    NASA Astrophysics Data System (ADS)

    Liu, Fangzhou; Leung, Yu Hang; Djurisić, Aleksandra B.; Liao, Changzhong; Shih, Kaimin

    2014-03-01

    Bisphenol A (BPA) and other organic pollutants from industrial wastewater have drawn increasing concern in the past decades regarding their environmental and biological risks, and hence developing strategies of effective degradation of BPA and other organic pollutants is imperative. Metal oxide nanostructures, in particular titanium oxide (TiO2) and zinc oxide (ZnO), have been demonstrated to exhibit efficient photodegradation of various common organic dyes. ZnO tetrapods are of special interest due to their low density of native defects which consequently lead to lower recombination losses and higher photocatalytic efficiency. Tetrapods can be obtained by relatively simple and low-cost vapor phase deposition in large quantity; the micron-scale size would also be advantageous for catalyst recovery. In this study, the photodegradation of BPA with ZnO tetrapods and TiO2 nanostructures under UV illumination were compared. The concentration of BPA dissolved in DI water was analyzed by high-performance liquid chromatography (HPLC) at specified time intervals. It was observed that the photocatalytic efficiency of ZnO tetrapods eventually surpassed Degussa P25 in free-standing form, and more than 80% of BPA was degraded after 60 min. Photodegradation of other organic dye pollutants by tetrapods and P25 were also examined. The superior photocatalytic efficiency of ZnO tetrapods for degradation of BPA and other organic dye pollutants and its correlation with the material properties were discussed.

  18. Prenatal development toxicity study of zinc oxide nanoparticles in rats

    PubMed Central

    Hong, Jeong-Sup; Park, Myeong-Kyu; Kim, Min-Seok; Lim, Jeong-Hyeon; Park, Gil-Jong; Maeng, Eun-Ho; Shin, Jae-Ho; Kim, Meyoung-Kon; Jeong, Jayoung; Park, Jin-A; Kim, Jong-Choon; Shin, Ho-Chul

    2014-01-01

    This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnOSM20(+) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo–fetal development after maternal exposure over the period of gestational days 5–19 with Sprague-Dawley rats. ZnOSM20(+) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations. Toxicity in the dams manifested as significantly decreased body weight after administration of 400 mg/kg/day NPs; reduced food consumption after administration of 200 and 400 mg/kg/day NPs; and decreased liver weight and increased adrenal glands weight after administration of 400 mg/kg/day NPs. However, no treatment-related difference in: number of corpora lutea; number of implantation sites; implantation rate (%); resorption; dead fetuses; litter size; fetal deaths and placental weights; and sex ratio were observed between the groups. On the other hand, significant decreases between treatment groups and controls were seen for fetal weights after administration of 400 mg/kg/day NPs. Morphological examinations of the fetuses demonstrated significant differences in incidences of abnormalities in the group administered 400mg/kg/day. Meanwhile, no significant difference was found in the Zn content of fetal tissue between the control and high-dose groups. These results showed that oral doses for the study with 15-days repeated of ZnOSM20(+) NPs were maternotoxic in the 200 mg/kg/day group, and embryotoxic in the 400 mg/kg/day group. PMID:25565834

  19. Prenatal development toxicity study of zinc oxide nanoparticles in rats.

    PubMed

    Hong, Jeong-Sup; Park, Myeong-Kyu; Kim, Min-Seok; Lim, Jeong-Hyeon; Park, Gil-Jong; Maeng, Eun-Ho; Shin, Jae-Ho; Kim, Meyoung-Kon; Jeong, Jayoung; Park, Jin-A; Kim, Jong-Choon; Shin, Ho-Chul

    2014-01-01

    This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnO(SM20(+)) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo-fetal development after maternal exposure over the period of gestational days 5-19 with Sprague-Dawley rats. ZnO(SM20(+)) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations. Toxicity in the dams manifested as significantly decreased body weight after administration of 400 mg/kg/day NPs; reduced food consumption after administration of 200 and 400 mg/kg/day NPs; and decreased liver weight and increased adrenal glands weight after administration of 400 mg/kg/day NPs. However, no treatment-related difference in: number of corpora lutea; number of implantation sites; implantation rate (%); resorption; dead fetuses; litter size; fetal deaths and placental weights; and sex ratio were observed between the groups. On the other hand, significant decreases between treatment groups and controls were seen for fetal weights after administration of 400 mg/kg/day NPs. Morphological examinations of the fetuses demonstrated significant differences in incidences of abnormalities in the group administered 400mg/kg/day. Meanwhile, no significant difference was found in the Zn content of fetal tissue between the control and high-dose groups. These results showed that oral doses for the study with 15-days repeated of ZnO(SM20(+)) NPs were maternotoxic in the 200 mg/kg/day group, and embryotoxic in the 400 mg/kg/day group. PMID:25565834

  20. Comparative effects of zinc oxide nanoparticles and dissolved zinc on zebrafish embryos and eleuthero-embryos: importance of zinc ions.

    PubMed

    Brun, Nadja Rebecca; Lenz, Markus; Wehrli, Bernhard; Fent, Karl

    2014-04-01

    The increasing use of zinc oxide nanoparticles (nZnO) and their associated environmental occurrence make it necessary to assess their potential effects on aquatic organisms. Upon water contact, nZnO dissolve partially to zinc (Zn(II)). To date it is not yet completely understood, whether effects of nZnO are solely or partly due to dissolved Zn(II). Here we compare potential effects of 0.2, 1 and 5mg/L nZnO and corresponding concentrations of released Zn(II) by water soluble ZnCl2 to two development stages of zebrafish, embryos and eleuthero-embryos, by analysing expressional changes by RT-qPCR. Another objective was to assess uptake and tissue distribution of Zn(II). Laser ablation-ICP-MS analysis demonstrated that uptake and tissue distribution of Zn(II) were identical for nZnO and ZnCl2 in eleuthero-embryos. Zn(II) was found particularly in the retina/pigment layer of eyes and brain. Both nZnO and dissolved Zn(II) derived from ZnCl2 had similar inhibiting effects on hatching, and they induced similar expressional changes of target genes. At 72hours post fertilization (hpf), both nZnO and Zn(II) delayed hatching at all doses, and inhibited hatching at 1 and 5 mg/L at 96 hpf. Both nZnO and Zn(II) lead to induction of metallothionein (mt2) in both embryos and eleuthero-embryos at all concentrations. Transcripts of oxidative stress related genes cat and Cu/Zn sod were also altered. Moreover, we show for the first time that nZnO exposure results in transcriptional changes of pro-inflammatory cytokines IL-1β and TNFα. Overall, transcriptional alterations were higher in embryos than eleuthero-embryos. The similarities of the effects lead to the conclusion that effects of nZnO are mainly related to the release of Zn(II).

  1. Effect of morphology and solvent on two-photon absorption of nano zinc oxide

    SciTech Connect

    Kavitha, M.K.; Haripadmam, P.C.; Gopinath, Pramod; Krishnan, Bindu; John, Honey

    2013-05-15

    Highlights: ► ZnO nanospheres and triangular structures synthesis by novel precipitation technique. ► The effect of precursor concentration on the size and shape of nano ZnO. ► Open aperture Z-scan measurements of the ZnO nanoparticle dispersions. ► Nanospheres exhibit higher two photon absorption coefficient than triangular nanostructures. ► Nanospheres dispersed in water exhibit higher two photon absorption coefficient than its dispersion in 2-propanol. - Abstract: In this paper, we report the effect of morphology and solvent on the two-photon absorption of nano zinc oxide. Zinc oxide nanoparticles in two different morphologies like nanospheres and triangular nanostructures are synthesized by novel precipitation technique and their two-photon absorption coefficient is measured using open aperture Z-scan technique. Experimental results show that the zinc oxide nanospheres exhibit higher two-photon absorption coefficient than the zinc oxide triangular nanostructures. The zinc oxide nanospheres dispersed in water exhibit higher two-photon absorption coefficient than that of its dispersion in 2-propanol. The zinc oxide nanospheres dispersed in water shows a decrease in two-photon absorption coefficient with an increase in on-axis irradiance. The result confirms the dependence of shape and solvent on the two-photon absorption of nano zinc oxide.

  2. Conductivity study of nitrogen-doped calcium zinc oxide prepared by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Ting; Lan, Wen-How; Huang, Kai-Feng; Lin, Jia-Ching; Chang, Kuo-Jen

    2016-01-01

    In this study, the spray pyrolysis method was used to prepare unintentionally doped and nitrogen-doped calcium zinc oxide films by using zinc acetate, calcium nitrate precursor, and ammonium acetate precursor. Morphological and structural analyses were conducted using scanning electron microscopy and X-ray diffraction. The results indicated that film grain size decreased as the nitrogen doping was increased. Both calcium oxide and zinc oxide structures were identified in the unintentionally doped calcium zinc oxide. When nitrogen doping was introduced, the film mainly exhibited a zinc oxide structure with preferred (002) and (101) orientations. The concentration and mobility were investigated using a Hall measurement system. P-type films with a mobility and concentration of 10.6 cm2 V-1 s-1 and 2.8×1017 cm-3, respectively, were obtained. Moreover, according to a temperature-dependent conductivity analysis, an acceptor state with activation energy 0.266 eV dominated the p-type conduction for the unintentionally doped calcium zinc oxide. By contrast, a grain boundary with a barrier height of 0.274-0.292 eV dominated the hole conduction for the nitrogen-doped calcium zinc oxide films.

  3. Texture and topography analysis of doxycycline hyclate thermosensitive systems comprising zinc oxide.

    PubMed

    Phaechamud, T; Mahadlek, J; Charoenteeraboon, J

    2013-07-01

    To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol(®) F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol(®) F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol(®) F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol(®) F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol(®) F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol(®) F127.

  4. Texture and Topography Analysis of Doxycycline Hyclate Thermosensitive Systems Comprising Zinc Oxide

    PubMed Central

    Phaechamud, T.; Mahadlek, J.; Charoenteeraboon, J.

    2013-01-01

    To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol® F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol® F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol® F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol® F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol® F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol® F127. PMID:24302791

  5. Physiologically based pharmacokinetic modeling of zinc oxide nanoparticles and zinc nitrate in mice.

    PubMed

    Chen, Wei-Yu; Cheng, Yi-Hsien; Hsieh, Nan-Hung; Wu, Bo-Chun; Chou, Wei-Chun; Ho, Chia-Chi; Chen, Jen-Kun; Liao, Chung-Min; Lin, Pinpin

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) have been widely used in consumer products, therapeutic agents, and drug delivery systems. However, the fate and behavior of ZnO NPs in living organisms are not well described. The purpose of this study was to develop a physiologically based pharmacokinetic model to describe the dynamic interactions of (65)ZnO NPs in mice. We estimated key physicochemical parameters of partition coefficients and excretion or elimination rates, based on our previously published data quantifying the biodistributions of 10 nm and 71 nm (65)ZnO NPs and zinc nitrate ((65)Zn(NO3)2) in various mice tissues. The time-dependent partition coefficients and excretion or elimination rates were used to construct our physiologically based pharmacokinetic model. In general, tissue partition coefficients of (65)ZnO NPs were greater than those of (65)Zn(NO3)2, particularly the lung partition coefficient of 10 nm (65)ZnO NPs. Sensitivity analysis revealed that 71 nm (65)ZnO NPs and (65)Zn(NO3)2 were sensitive to excretion and elimination rates in the liver and gastrointestinal tract. Although the partition coefficient of the brain was relative low, it increased time-dependently for (65)ZnO NPs and (65)Zn(NO3)2. The simulation of (65)Zn(NO3)2 was well fitted with the experimental data. However, replacing partition coefficients of (65)ZnO NPs with those of (65)Zn(NO3)2 after day 7 greatly improved the fitness of simulation, suggesting that ZnO NPs might decompose to zinc ion after day 7. In this study, we successfully established a potentially predictive dynamic model for slowly decomposed NPs. More caution is suggested for exposure to (65)ZnO NPs <10 nm because those small (65)ZnO NPs tend to accumulate in the body for a relatively longer time than 71 nm (65)ZnO NPs and (65)Zn(NO3)2 do. PMID:26491297

  6. An Electrochemical Glucose Sensor Based on Zinc Oxide Nanorods.

    PubMed

    Marie, Mohammed; Mandal, Sanghamitra; Manasreh, Omar

    2015-01-01

    A glucose electrochemical sensor based on zinc oxide (ZnO) nanorods was investigated. The hydrothermal sol-gel growth method was utilized to grow ZnO nanorods on indium tin oxide-coated glass substrates. The total active area of the working electrode was 0.3 × 0.3 cm2 where titanium metal was deposited to enhance the contact. Well aligned hexagonal structured ZnO nanorods with a diameter from 68 to 116 nm were obtained. The excitonic peak obtained from the absorbance spectroscopy was observed at ~370 nm. The dominant peak of Raman spectroscopy measurement was at 440 cm(-1), matching with the lattice vibration of ZnO. The uniform distribution of the GOx and Nafion membrane that has been done using spin coating technique at 4000 rotations per minute helps in enhancing the ion exchange and increasing the sensitivity of the fabricated electrochemical sensor. The amperometric response of the fabricated electrochemical sensor was 3 s. The obtained sensitivity of the fabricated ZnO electrochemical sensor was 10.911 mA/mM·cm2 and the lower limit of detection was 0.22 µM. PMID:26263988

  7. An Electrochemical Glucose Sensor Based on Zinc Oxide Nanorods.

    PubMed

    Marie, Mohammed; Mandal, Sanghamitra; Manasreh, Omar

    2015-01-01

    A glucose electrochemical sensor based on zinc oxide (ZnO) nanorods was investigated. The hydrothermal sol-gel growth method was utilized to grow ZnO nanorods on indium tin oxide-coated glass substrates. The total active area of the working electrode was 0.3 × 0.3 cm2 where titanium metal was deposited to enhance the contact. Well aligned hexagonal structured ZnO nanorods with a diameter from 68 to 116 nm were obtained. The excitonic peak obtained from the absorbance spectroscopy was observed at ~370 nm. The dominant peak of Raman spectroscopy measurement was at 440 cm(-1), matching with the lattice vibration of ZnO. The uniform distribution of the GOx and Nafion membrane that has been done using spin coating technique at 4000 rotations per minute helps in enhancing the ion exchange and increasing the sensitivity of the fabricated electrochemical sensor. The amperometric response of the fabricated electrochemical sensor was 3 s. The obtained sensitivity of the fabricated ZnO electrochemical sensor was 10.911 mA/mM·cm2 and the lower limit of detection was 0.22 µM.

  8. CSA doped polypyrrole-zinc oxide thin film sensor

    NASA Astrophysics Data System (ADS)

    Chougule, M. A.; Jundale, D. M.; Raut, B. T.; Sen, Shashwati; Patil, V. B.

    2013-02-01

    The polypyrrole-zinc oxide (PPy-ZnO) hybrid sensor doped with different weight ratios of camphor sulphonic acid (CSA) were prepared by spin coating technique. These CSA doped PPy-ZnO hybrids were characterized by field emission scanning electron microscope (FESEM) and fourier transform infrared (FTIR) which proved the formation of polypyrrole, PPy-ZnO and the interaction between polypyrrole - ZnO (PPy-ZnO) hybrid with CSA doping. The gas sensing properties of the PPy-ZnO hybrid films doped with CSA have been studied for oxidizing (NO2) as well as reducing (H2S, NH3, CH4OH and CH3OH) gases at room temperature. We demonstrate that CSA doped PPy-ZnO hybrid films are highly selective to NO2 along with high-sensitivity at low concentration (80% to 100 ppm) and better stability, which suggested that the CSA doped PPy-ZnO hybrid films are potential candidate for NO2 detection at room temperature.

  9. Spatial atomic layer deposition of zinc oxide thin films.

    PubMed

    Illiberi, A; Roozeboom, F; Poodt, P

    2012-01-01

    Zinc oxide thin films have been deposited at high growth rates (up to ~1 nm/s) by spatial atomic layer deposition technique at atmospheric pressure. Water has been used as oxidant for diethylzinc (DEZ) at deposition temperatures between 75 and 250 °C. The electrical, structural (crystallinity and morphology), and optical properties of the films have been analyzed by using Hall, four-point probe, X-ray diffraction, scanning electron microscopy, spectrophotometry, and photoluminescence, respectively. All the films have c-axis (100) preferential orientation, good crystalline quality and high transparency (∼ 85%) in the visible range. By varying the DEZ partial pressure, the electrical properties of ZnO can be controlled, ranging from heavily n-type conductive (with 4 mOhm.cm resistivity for 250 nm thickness) to insulating. Combining the high deposition rates with a precise control of functional properties (i.e., conductivity and transparency) of the films, the industrially scalable spatial ALD technique can become a disruptive manufacturing method for the ZnO-based industry.

  10. Influence Of pH On The Transport Of Nanoscale Zinc Oxide In Saturated Porous Media

    EPA Science Inventory

    Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport mechanism of nZnO in such e...

  11. Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron

    PubMed Central

    Rosado, Jorge L.; Díaz, Margarita; Muñoz, Elsa; Westcott, Jamie L.; González, Karla E.; Krebs, Nancy F.; Caamaño, María C.; Hambidge, Michael

    2013-01-01

    Background Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. Objective To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. Methods A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. Results The mean (± SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 ± 0.07, 0.36 ± 0.05, and 0.37 ± 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 ± 0.04, 0.33 ± 0.02, and 0.32 ± 0.05, respectively) and similar amounts of zinc absorbed (4.8 ± 0.7, 4.5 ± 0.3, and 4.8 ± 0.7 mg/day, respectively). Conclusions Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour. PMID:23424892

  12. An integrated (electro- and bio-oxidation) approach for remediation of industrial wastewater containing azo-dyes: Understanding the degradation mechanism and toxicity assessment.

    PubMed

    Aravind, Priyadharshini; Selvaraj, Hosimin; Ferro, Sergio; Sundaram, Maruthamuthu

    2016-11-15

    A hybrid approach for the remediation of recalcitrant dye wastewater is proposed. The chlorine-mediated electrochemical oxidation of real textile effluents and synthetic samples (using Ti/IrO2-RuO2-TiO2 anodes), lead to discoloration by 92% and 89%, respectively, in 100min, without significant mineralization. The remediation was obtained through biodegradation, after removing the residual bio-toxic active chlorine species via sunlight exposition. Results show that the electrochemical discoloration enhances the effluent biodegradability with about 90% COD removal employing acclimatized naphthalene-degrading bacterial consortia, within 144h. Based on results obtained through FT-IR and GC-MS, it is likely that azo group stripping and oxidative cleavage of dyes occur due to the nucleophilic attack of active chlorine species during electro-oxidation. This leads to generation of aromatic intermediates which are further desulfonated, deaminated or oxidized only at their functional groups. These aromatic intermediates were mineralized into simpler organic acids and aldehydes by bacterial consortia. Phyto-toxicity trials on Vigna radiata confirmed the toxic nature of the untreated dye solutions. An increase in root and shoot development was observed with the electrochemically treated solutions, the same was higher in case of bio-treated solutions. Overall, obtained results confirm the capability of the proposed hybrid oxidation scheme for the remediation of textile wastewater. PMID:27427887

  13. 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 ...

  14. Inhibitory action of two zinc oxide sources on the ex vivo growth of porcine small intestine bacteria.

    PubMed

    Vahjen, W; Zentek, J; Durosoy, S

    2012-12-01

    Pharmacological dosage of zinc oxide in piglet weaning diets is a common practice to improve growth performance and gut health. However, high zinc excretion in animal wastes poses environmental challenges. Alternatives to current practice are studied. In this study, the inhibitory action of 2 zinc oxide sources on the ex vivo growth of small intestinal bacteria from weaned piglets was studied. Lag time was higher (P < 0.05) in media supplemented with a new zinc oxide preparation in stomach samples, but not in jejunum samples. Bacterial growth reduction (P < 0.05) was more drastic and more rapid in media supplemented with the new zinc oxide preparation.

  15. Hydrothermal synthesis of zinc oxide nanoparticles using rice as soft biotemplate

    PubMed Central

    2013-01-01

    Background Rice as a renewable, abundant bio-resource with unique characteristics can be used as a bio-template to synthesize various functional nanomaterials. Therefore, the effect of uncooked rice flour as bio-template on physico-chemical properties, especially the morphology of zinc oxide nanostructures was investigated in this study. The ZnO particles were synthesized through hydrothermal-biotemplate method using zinc acetate-sodium hydroxide and uncooked rice flour at various ratios as precursors at 120°C for 18 hours. Results The results indicate that rice as a bio-template can be used to modify the shape and size of zinc oxide particles. Different morphologies, namely flake-, flower-, rose-, star- and rod-like structures were obtained with particle size at micro- and nanometer range. Pore size and texture of the resulting zinc oxide particles were found to be template-dependent and the resulting specific surface area enhanced compared to the zinc oxide synthesized without rice under the same conditions. However, optical property particularly the band gap energy is generally quite similar. Conclusion Pure zinc oxide crystals were successfully synthesized using rice flour as biotemplate at various ratios of zinc salt to rice. The size- and shape-controlled capability of rice to assemble the ZnO particles can be employed for further useful practical applications. PMID:23919386

  16. Flexible and monolithic zinc oxide bionanocomposite foams by a bacterial cellulose mediated approach for antibacterial applications.

    PubMed

    Wang, Peipei; Zhao, Jun; Xuan, Ruifei; Wang, Yun; Zou, Chen; Zhang, Zhiquan; Wan, Yizao; Xu, Yan

    2014-05-14

    The use of self-assembled biomacromolecules in the development of functional bionanocomposite foams is one of the best lessons learned from nature. Here, we show that monolithic, flexible and porous zinc oxide bionanocomposite foams with a hierarchical architecture can be assembled through the mediation of bacterial cellulose. The assembly is achieved by controlled hydrolysis and solvothermal crystallization using a bacterial cellulose aerogel as a template in a non-aqueous polar medium. The bionanocomposite foam with a maximum zinc oxide loading of 70 wt% is constructed of intimately packed spheres of aggregated zinc oxide nanocrystals exhibiting a BET surface area of 92 m(2) g(-1). The zinc oxide bionanocomposite foams show excellent antibacterial activity, which give them potential value as self-supporting wound dressing and water sterilization materials.

  17. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    PubMed

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  18. Formation of Flexible and Transparent Indium Gallium Zinc Oxide/Ag/Indium Gallium Zinc Oxide Multilayer Film

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kim, Da-Som; Kim, Sun-Kyung; Yoo, Young-Zo; Lee, Jeong Hwan; Kim, Sang-Woo; Seong, Tae-Yeon

    2016-08-01

    In this study, the electrical, optical, and bending characteristics of amorphous indium gallium zinc oxide (IGZO)/Ag/IGZO (39 nm/19 nm/39 nm) multilayer films deposited on polyethylene terephthalate (PET) substrate at room temperature were investigated and compared with those of Sn-doped indium oxide (ITO) (100 nm thick) films. At 500 nm the ITO film transmitted 91.3% and the IGZO/Ag/IGZO multilayer film transmitted 88.8%. The calculated transmittance spectrum of the multilayer film was similar to the experimental result. The ITO film and IGZO/Ag/IGZO multilayer film, respectively, showed carrier concentrations of 1.79 × 1020 and 7.68 × 1021 cm-3 and mobilities of 27.18 cm2/V s and 18.17 cm2/V s. The ITO film had a sheet resistance of 134.9 Ω/sq and the IGZO/Ag/IGZO multilayer film one of 5.09 Ω/sq. Haacke's figure of merit (FOM) was calculated to be 1.94 × 10-3 for the ITO film and 45.02 × 10-3 Ω-1 for the IGZO/Ag/IGZO multilayer film. The resistance change of 100 nm-thick ITO film was unstable even after five cycles, while that of the IGZO/Ag/IGZO film was constant up to 1000 cycles.

  19. Transport of Zinc Oxide Nanoparticles in a Simulated Gastric Environment

    NASA Astrophysics Data System (ADS)

    Mayfield, Ryan T.

    Recent years have seen a growing interest in the use of many types of nano sized materials in the consumer sector. Potential uses include encapsulation of nutrients, providing antimicrobial activity, altering texture, or changing bioavailability of nutrients. Engineered nanoparticles (ENP) possess properties that are different than larger particles made of the same constituents. Properties such as solubility, aggregation state, and toxicity can all be changed as a function of size. The gastric environment is an important area for study of engineered nanoparticles because of the varied physical, chemical, and enzymatic processes that are prevalent there. These all have the potential to alter those properties of ENP that make them different from their bulk counterparts. The Human Gastric Simulator (HGS) is an advanced in vitro model that can be used to study many facets of digestion. The HGS consists of a plastic lining that acts as the stomach cavity with two sets of U-shaped arms on belts that provide the physical forces needed to replicate peristalsis. Altering the position of the arms or changing the speed of the motor which powers them allows one to tightly hone and replicate varied digestive conditions. Gastric juice, consisting of salts, enzymes, and acid levels which replicate physiological conditions, is introduced to the cavity at a controllable rate. The release of digested food from the lumen of simulated stomach is controlled by a peristaltic pump. The goal of the HGS is to accurately and repeatedly simulate human digestion. This study focused on introducing foods spiked with zinc oxide ENP and bulk zinc oxide into the HGS and then monitoring how the concentration of each changed at two locations in the HGS over a two hour period. The two locations chosen were the highest point in the lumen of the stomach, which represented the fundus, and a point just beyond the equivalent of the pylorus, which represented the antrum of the stomach. These points were

  20. 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

  1. Synthesis and characterization of nanostructured zinc oxide layers for sensor applications

    SciTech Connect

    Krasteva, L. K.; Dimitrov, D. Tz.; Papazova, K. I.; Nikolaev, N. K.; Peshkova, T. V.; Moshnikov, V. A.; Gracheva, I. E. Karpova, S. S.; Kaneva, N. V.

    2013-04-15

    Fractal structures and arrays of nanowires based on zinc oxide are fabricated by two different methods, sol-gel dip-coating and chemical bath deposition combined with sol-gel synthesis. The gas-sensitive properties of the structures are analyzed. It is found that the greatest sensitivity to reducing ethanol vapor is exhibited by the structure with a lower layer in the form of an array of zinc-oxide nanowires modified by four immersions in a copper nitrate solution.

  2. 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

  3. The role of intracellular zinc release in aging, oxidative stress, and Alzheimer’s disease

    PubMed Central

    McCord, Meghan C.; Aizenman, Elias

    2014-01-01

    Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury. PMID:24860495

  4. [Permeation of triamcinolone acetonide and zinc oxide from a shake lotion].

    PubMed

    Stüttgen, G; Bauer, E; Wiese, G; Maue, V

    1983-08-01

    Triamcinolone-acetonide crystals suspended in a zinc oxide shake lotion permeate the deeper skin layers especially if applied to a damaged horny layer. The influx rate of the corticosteroid is approximately 20 times higher in damaged skin (e.g. removing of horny layer by stripping) than in healthy skin. Zinc oxide is absorbed by the middle and lower layers of the horny layer respectively epidermis, out of the triamcinolone-acetonide shake lotion. The corticosteroid and zinc component as well as a physical properties of the shake lotion have a therapeutical effect.

  5. Alterations of Bio-elements, Oxidative, and Inflammatory Status in the Zinc Deficiency Model in Rats.

    PubMed

    Doboszewska, Urszula; Szewczyk, Bernadeta; Sowa-Kućma, Magdalena; Noworyta-Sokołowska, Karolina; Misztak, Paulina; Gołębiowska, Joanna; Młyniec, Katarzyna; Ostachowicz, Beata; Krośniak, Mirosław; Wojtanowska-Krośniak, Agnieszka; Gołembiowska, Krystyna; Lankosz, Marek; Piekoszewski, Wojciech; Nowak, Gabriel

    2016-01-01

    Our previous study showed that dietary zinc restriction induces depression-like behavior with concomitant up-regulation of the N-methyl-D-aspartate receptor (NMDAR). Because metal ions, oxidative stress, and inflammation are involved in depression/NMDAR function, in the present study, bio-elements (zinc, copper, iron, magnesium, and calcium), oxidative (thiobarbituric acid-reactive substances; protein carbonyl content), and inflammatory (IL-1α, IL-1β) factors were measured in serum, hippocampus (Hp), and prefrontal cortex (PFC) of male Sprague-Dawley rats subjected to a zinc-adequate (ZnA) (50 mg Zn/kg) or a zinc-deficient (ZnD) (3 mg Zn/kg) diet for 4 or 6 weeks. Both periods of dietary zinc restriction reduced serum zinc and increased serum iron levels. At 4 weeks, lowered zinc level in the PFC and Hp as well as lowered iron level in the PFC of the ZnD rats was observed. At 6 weeks, however, iron level was increased in the PFC of these rats. Although at 6 weeks zinc level in the PFC did not differ between the ZnA and ZnD rats, extracellular zinc concentration after 100 mM KCl stimulation was reduced in the PFC of the ZnD rats and was accompanied by increased extracellular iron and glutamate levels (as measured by the in vivo microdialysis). The examined oxidative and inflammatory parameters were generally enhanced in the tissue of the ZnD animals. The obtained data suggest dynamic redistribution of bio-elements and enhancement of oxidative/inflammatory parameters after dietary zinc restriction, which may have a link with depression-like behavior/NMDAR function/neurodegeneration.

  6. Application of RF magnetron sputtering for growth of AZO on glass substrate

    NASA Astrophysics Data System (ADS)

    Ghorannevis, Z.; Akbarnejad, E.; Salar Elahi, A.; Ghoranneviss, M.

    2016-08-01

    Aluminum zinc oxide (AZO), as one of the most promising transparent conducting oxide (TCO) materials, has now been widely used in thin film solar cells. In this study the optimization process of the RF magnetron sputtered AZO films was performed at room temperature by studying its physical properties such as structural, optical, electrical and morphological at different deposition times (10, 20, 40 and 60 min) for its use as a front contact for the Cadmium Telluride (CdTe) based thin film solar cell applications. Influence of the deposition time was investigated on the physical properties of the AZO thin film by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), spectrophotometer and four point probes. XRD analysis suggests that the preferred orientation of grains for all the samples prepared at different growth times are along (002) plane having the hexagonal structure. From optical measurements the films show an average transmission over 60%. Moreover it was found that by increasing the growth time, which implies increasing the film thicknesses as well as improving the crystallinity the resistivity of the grown films decrease from the 10-2 Ωcm to the order of 10-3 Ωcm.

  7. Study of phosphate removal from aqueous solution by zinc oxide.

    PubMed

    Luo, Zhen; Zhu, Suiyi; Liu, Zhongmou; Liu, Jiancong; Huo, Mingxin; Yang, Wu

    2015-09-01

    Zinc oxide (ZnO) was synthesized and used to investigate the mechanism of phosphate removal from aqueous solution. ZnO particles were characterized by X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy before and after adsorption. Batch experiments were carried out to investigate the kinetics, isotherms, effects of initial pH and co-existing anions. The adsorption process was rapid and equilibrium was almost reached within 150 min. The adsorption kinetics were described well by a pseudo-second-order equation, and the maximum phosphate adsorption capacity was 163.4 mg/g at 298 K and pH ∼6.2±0.1. Thermodynamic analysis indicated the phosphate adsorption onto ZnO was endothermic and spontaneous. The point of zero charge of ZnO was around 8.4 according to the pH-drift method. Phosphate adsorption capacity reduced with the increasing initial solution pH values. The ligand exchange and Lewis acid-base interaction dominated the adsorption process in the lower and the higher pH range, respectively. Nitrate, sulfate and chloride ions had a negligible effect on phosphate removal, while carbonate displayed significant inhibition behavior.

  8. Highly Conducting Transparent Indium-Doped Zinc Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Singh, Budhi; Ghosh, Subhasis

    2014-09-01

    Highly conducting transparent indium-doped zinc oxide (IZO) thin films have been achieved by controlling different growth parameters using radio frequency magnetron sputtering. The structural, electrical, and optical properties of the IZO thin films have been investigated for varied indium content and growth temperature ( T G) in order to find out the optimum level of doping to achieve the highest conducting transparent IZO thin films. The highest mobility and carrier concentration of 11.5 cm2/V-s and 3.26 × 1020 cm-3, respectively, have been achieved in IZO doped with 2% indium. It has been shown that as T G of the 2% IZO thin films increase, more and more indium atoms are substituted into Zn sites leading to shift in (002) peaks towards higher angles which correspond to releasing the stress within the IZO thin film. The minimum resistivity of 5.3 × 10-4 Ω-cm has been achieved in 2% indium-doped IZO grown at 700°C.

  9. Fungus mediated biosynthesis and characterization of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Venkatesh, K. S.; Palani, N. S.; Krishnamoorthi, S. R.; Thirumal, V.; Ilangovan, R.

    2013-06-01

    Recently nanomaterials have been synthesized through biological approach due to its biocompatibility, inexpensive, eco friendly and it offers easiest experimental protocol and so on. ZnO can be potentially used in various applications. This present study reports the fungus mediated extra-cellular bio synthesis of ZnO nanorods using Fusarium Solani. The dried powder was calcined at 350°C for 1 hour in air. The thermal property of the as synthesized ZnO nanopowder was analyzed through Thermo gravimetric /Differential Thermo gravimetric (TGA / DTG) analysis. The structural and morphological properties of the calcined ZnO nanopowder were studied by XRD and SEM analysis respectively. X ray diffraction result revealed that a peak located at 2θ = 36.2° with (101) plane confirms the presence of Zinc oxide with Hexagonal crystal system. The morphology of the calcined ZnO powder was analyzed by Scanning Electron Microscopy and it clearly indicates the presence of ZnO nanorods. The diameter of the nanorods is in the range of 60 to 95 nm.

  10. Antibacterial effect of zinc oxide nanoparticles combined with ultrasound

    NASA Astrophysics Data System (ADS)

    Seil, Justin T.; Webster, Thomas J.

    2012-12-01

    Using Staphylococcus aureus (S. aureus), the present study investigated the antibacterial effect of ZnO nanoparticles both in the absence and presence of ultrasound stimulation. While the antibacterial effect of control nanoparticle chemistries (Al2O3) alone was either weak or unobservable under the conditions tested, the antibacterial effect of ZnO alone was significant, providing over a four log reduction (equivalent to antibiotics) compared to no treatment after just 8 h. The antibacterial effect was enhanced as ZnO particle diameter decreased. Specifically, when testing the antibacterial effect against bacteria populations relevant to infection, a 500 μg ml-1 dose of zinc oxide nanoparticles with a diameter of 20 nm reduced S. aureus populations by four orders of magnitude after 8 and 24 h, compared to control groups with no nanoparticles. This was accomplished without the use of antibiotics, to which bacteria are developing a resistance anyway. The addition of ultrasound stimulation further reduced the number of viable colony-forming units present in a planktonic cell suspension by 76% compared to nanoparticles alone. Lastly, this study provided a mechanism for how ZnO nanoparticles in the presence of ultrasound decrease bacteria functions by demonstrating greater hydrogen peroxide generation by S. aureus compared to controls. These results indicated that small-diameter ZnO nanoparticles exhibited strong antibacterial properties that can be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications.

  11. Fabrication and Electrical Characterization of Zinc Oxide Nanowires

    NASA Astrophysics Data System (ADS)

    Zhang, Daqing; Lee, Chun-Hong; Berven, Chris; Katkanant, Vanvilai

    2009-03-01

    One dimensional semiconducting zinc oxide (ZnO) nanowires have drawn attractive attentions in the past years. The unique electrical, optical, and piezoelectric properties of ZnO nanowires make them broaden applications ranging from light emitting diode and lasers, solar cells, photodetectors, electron transporters and transistors, to piezoelectric generators. In our research, two-terminal current-voltage (I-V) measurements were conducted to determine the electrical conductivity alternation of the ZnO nanowires under laser irradiation, and various gaseous surroundings. The I-V curves at the temperature ranged from 150 to 300 K were recorded in vacuum. The Arrhenius plot shows perfect linear relation between I and 1/T. The donor lever of the semiconducting nanowire is about 326 meV. We observed that the current increased 50% with laser on in comparison to that with it off; it raised by a factor of four under ambient reductive gas CO. In addition, the I-V behaviors were found to be reversible with those various environments. Further studies on the possible nano- devices such as optical switches and chemical sensors are undergoing.

  12. Study of phosphate removal from aqueous solution by zinc oxide.

    PubMed

    Luo, Zhen; Zhu, Suiyi; Liu, Zhongmou; Liu, Jiancong; Huo, Mingxin; Yang, Wu

    2015-09-01

    Zinc oxide (ZnO) was synthesized and used to investigate the mechanism of phosphate removal from aqueous solution. ZnO particles were characterized by X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy before and after adsorption. Batch experiments were carried out to investigate the kinetics, isotherms, effects of initial pH and co-existing anions. The adsorption process was rapid and equilibrium was almost reached within 150 min. The adsorption kinetics were described well by a pseudo-second-order equation, and the maximum phosphate adsorption capacity was 163.4 mg/g at 298 K and pH ∼6.2±0.1. Thermodynamic analysis indicated the phosphate adsorption onto ZnO was endothermic and spontaneous. The point of zero charge of ZnO was around 8.4 according to the pH-drift method. Phosphate adsorption capacity reduced with the increasing initial solution pH values. The ligand exchange and Lewis acid-base interaction dominated the adsorption process in the lower and the higher pH range, respectively. Nitrate, sulfate and chloride ions had a negligible effect on phosphate removal, while carbonate displayed significant inhibition behavior. PMID:26322756

  13. Detrimental Effects of Zinc Oxide Nanoparticles on Amphibian Life Stages.

    PubMed

    Spence, Austin Reid; Hopkins, Gareth Rowland; Neuman-Lee, Lorin Anne; Smith, Geoffrey David Stuart; Brodie, Edmund Darrell; French, Susannah Smith

    2016-08-01

    While the use of nanoparticles has dramatically increased in recent years, the ecological consequences are not well known. In particular, little research has been done to investigate the potentially detrimental effects of nanoparticles on amphibians, especially across all life-history stages of salamanders and newts (caudates). To address this dearth in knowledge, we examined the effects of zinc oxide (ZnO) nanoparticles on egg, larval, and adult Rough-skinned Newts (Taricha granulosa). Chronic toxicity was tested on eggs and larvae, and acute toxicity was tested on eggs, larvae, and adults. For eggs, chronic exposure to ZnO nanoparticles caused higher mortality at 10.0 and 100.0 mg L(-1) compared to 0.0, 0.1, and 1.0 mg L(-1) . When given an acute exposure (24 hr) to 10.0 mg L(-1) nanoparticles at a late developmental stage, larvae hatched 5 days early, at a decreased developmental stage, and smaller size compared to the control. Chronic and acute exposure of larvae increased mortality up to 75% at both 10.0 and 100.0 mg L(-1) and exhibited sublethal effects, most dramatically, severe gill degradation. These results suggest nanoparticles can have lethal and sublethal effects on all life stages of amphibians. PMID:27453487

  14. Synthesis and characterisation: Zinc oxide-sulfide nanocomposites

    NASA Astrophysics Data System (ADS)

    Verma, Prinsa; Pandey, Avinash C.; Bhargava, R. N.

    2009-11-01

    A novel synthesis method is presented for the preparation of nanosized-semiconductor zinc oxide-sulphide (ZnO/ZnS) core-shell nanocomposites, both formed sequentially from a single-source solid precursor. ZnO nanocrystals were synthesized by a simple co-precipitation method and ZnO/ZnS core-shell nanocomposites were successfully fabricated by sulfidation of ZnO nanocrystals via a facile chemical synthesis at room temperature. The as-obtained samples were characterized by X-ray diffraction and transmission electron microscopy. The results showed that the pure ZnO nanocrystals were hexagonal wurtzite crystal structures and the ZnS nanoparticles were sphalerite structure with the size of about 10 nm grown on the surface of the ZnO nanocrystals. Optical properties measured reveal that ZnO/ZnS core-shell nanocomposites have integrated the photoluminescent effect of ZnO and ZnS. Based on the results of the experiments, a possible formation mechanism of ZnO/ZnS core-shell nanocomposites was also suggested. This treatment is suggested to improve various properties of optoelectronically valuable ZnO/ZnS nanocomposites. These nanosized semiconductor nanocomposites can form a new class of luminescent materials for various applications.

  15. Sonochemical approach for rapid growth of zinc oxide nanowalls

    NASA Astrophysics Data System (ADS)

    Nayak, Avinash P.; Katzenmeyer, Aaron M.; Gosho, Yasuhiro; Tekin, Bayram; Islam, M. Saif

    2012-06-01

    The sonochemical process drives chemical reactions with sound fields by creating extraordinarily high density of energy, pressure and temperatures. The process resulted in a number of unexpected chemical species and thought-provoking results in the recent past. In this paper, we present a new sonochemical approach to synthesize ZnO (zinc oxide) nanowalls (NWalls) on aluminum and alumina coated substrates at room ambient conditions. We achieved highly dense and uniform ZnO NWalls in areas that are coated with Al or Al2O3 (alumina). The synthesis process was shown not to occur on Si, SiO2, Cr, or Ag surfaces. A series of experiments on understanding the growth kinetics offers detailed insight into the growth dynamics over time. Photoluminescence (PL) measurements, UV Vis spectroscopy, and SEM-EDS results confirm NWalls composed of crystalline ZnO that are formed via Al assisted growth induced by phase transformations under extraordinary pressure, temperature, and chemical growth kinetics. The chemical growth method as reported here, is applicable to arbitrary substrates coated with an Al thin film. We demonstrate the applications of the as-formed NWalls in UV photoconductors and gas sensors.

  16. Gas Effect On Plasma Dynamics Of Laser Ablation Zinc Oxide

    SciTech Connect

    Abdelli-Messaci, S.; Kerdja, T.; Lafane, S.; Malek, S.

    2008-09-23

    In order to synthesis zinc oxide thin films and nanostructures, laser ablation of ZnO target into both vacuum and oxygen atmosphere was performed. The gas effect on the plume dynamics was studied for O{sub 2} pressures varied between 10{sup -2} to 70 mbar. Plasma plume evolution was investigated by ICCD camera fast imaging. The plasma was created by a KrF excimer laser ({lambda} = 248 nm, {tau} = 25 ns) at a fluence of 2 J/cm{sup 2}. The light emitted by the plume was observed along the perpendicular to the ejection direction through a fast intensified charge-coupled device (ICCD). We have found that the plasma dynamics is very affected by the gas pressures. The photographs reveal the stratification of plasma into slow and fast components for 0.5 mbar O{sub 2} pressures and beyond. The photographs also show the apparition of hydrodynamic instabilities which are related to chemical reactions between the plasma and the surrounding gas for a certain range of pressures.

  17. Immobilization of diastase α-amylase on nano zinc oxide.

    PubMed

    Antony, Navya; Balachandran, S; Mohanan, P V

    2016-11-15

    Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08mg/ml than the free enzyme whose Km is 0.45±.05mg/ml. The Vmax of immobilized enzyme was about 2.92±.02mg/ml/min and that of free enzyme was 7.14±.02mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30days of storage while free enzyme lost its activity within 7days. About 80% of enzyme retained activity after 4 cycles of reuse.

  18. Biochemical responses of duckweed (Spirodela polyrhiza) to zinc oxide nanoparticles.

    PubMed

    Hu, Changwei; Liu, Yimeng; Li, Xiuling; Li, Mei

    2013-05-01

    The present study focuses on the biochemical responses of the aquatic plant duckweed (Spirodela polyrhiza L.) to zinc oxide nanoparticles (ZnO NPs). Laboratory experiments were performed using a 96-h exposure to 25-nm NPs at different concentrations (0, 1, 10, and 50 mg/L). Growth, chlorophyll-to-pheophytin ratio (D665/D665a) and activities of superoxide dismutase, catalase, peroxidase (POD), and Na(+), K(+)-ATPase were determined as indices to evaluate the toxicity of NPs in the culture medium. To understand better whether the Zn(2+) released from the ZnO NP suspensions plays a key role in toxicity of the NPs, we investigated particle aggregation and dissolution in the medium. Furthermore, two exposure treatments for the group with the highest concentration (50 mg/L) were performed: (1) exposure for the full 96 h (50a treatment) and (2) the medium being replaced with culture medium without NPs after 12 h (50b treatment). Our results indicate that ZnO NPs induced adverse effects in S. polyrhiza at the concentration of 50 mg/L in the culture medium. Zn(2+) released from the NPs might be the main source of its toxicity to this species.

  19. Morphology Control of Zinc Oxide Nanostructure on Single Layer Graphene.

    PubMed

    Ahn, Seungbae; Vijayarangamuthu, K; Jeon, Ki-Jeon

    2016-05-01

    Various morphologies of zinc oxide (ZnO) nanostructures on single layer graphene were synthesized by electrodeposition method. The current density was utilized to control the morphology of the ZnO. The Scanning Electron Microscope (SEM) was used to examine the surface morphology of the samples. SEM analysis shows morphology changes to nanorod, flower, and flakes with increase in the current density from 0.1, 0.2, and 0.3 mA/cm(-1) respectively. The XRD, XPS, and Raman spectroscopy were adopted to characterize the ZnO nanostructure and to understand the formation of various morphologies. The Raman result clearly shows extra modes due to for flakes structure caused by c-axis orientation along the substrate direction. Further, XPS data also supports formation of ZnO without any other intermediate compound such as Zn(OH)2. The formation of various morphologies was correlated to the formation different ratio of Zn2+ and OH- ions and the change in growth direction due to various current densities. PMID:27483766

  20. Structural transformation in nickel doped zinc oxide nanostructures

    SciTech Connect

    Goswami, Navendu; Sahai, Anshuman

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► A systematic study of 1–10% Ni doped ZnO nanostructures (Ni:ZnO NS). ► Effect of Ni concentration on properties of Ni:ZnO NS was intensively investigated. ► Structural transformation in Ni:ZnO NS demonstrated through characterizations. ► Alteration in vibrational modes of Ni:ZnO NS were meticulously analyzed. ► Intricacies of structural evolution, from particles to rods, were comprehended. -- Abstract: In this article, structural transformation in nickel doped zinc oxide nanostructures is reported. The ZnO nanostructures are synthesized with 1–10% of nickel doping through a chemical precipitation method. The undoped and doped nanostructures were systematically investigated employing X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM/SEM), Fourier transform infrared (FTIR) and micro-Raman spectroscopy (μRS). The wurtzite phase of the material and associated lattice parameters were ascertained through XRD analysis. TEM/SEM images reveal the structural transformation of ZnO nanostructures with variation in nickel doping. The study of vibrational modes of nanostructures at different stages of structural transformation, as performed through FTIR and Raman spectroscopy, assist in deciphering the pivotal role of doping concentration in gradual evolution of nickel doped ZnO structure from nanoparticles to nanorods.

  1. Zinc oxide nanowire gamma ray detector with high spatiotemporal resolution

    NASA Astrophysics Data System (ADS)

    Mayo, Daniel C.; Nolen, J. Ryan; Cook, Andrew; Mu, Richard R.; Haglund, Richard F.

    2016-03-01

    Conventional scintillation detectors are typically single crystals of heavy-metal oxides or halides doped with rare-earth ions that record the recombination of electron-hole pairs by photon emission in the visible to ultraviolet. However, the light yields are typically low enough to require photomultiplier detection with the attendant instrumental complications. Here we report initial studies of gamma ray detection by zinc oxide (ZnO) nanowires, grown by vapor-solid deposition. The nanowires grow along the c-axis in a wurtzite structure; they are typically 80 nm in diameter and have lengths of 1- 2 μm. The nanowires are single crystals of high quality, with a photoluminescence (PL) yield from band-edge exciton emission in the ultraviolet that is typically one hundred times larger than the PL yield from defect centers in the visible. Nanowire ensembles were irradiated by 662 keV gamma rays from a Cs-137 source for periods of up to ten hours; gamma rays in this energy range interact by Compton scattering, which in ZnO creates F+ centers that relax to form singly-charged positive oxygen vacancies. Following irradiation, we fit the PL spectra of the visible emission with a sum of Gaussians at the energies of the known defects. We find highly efficient PL from the irradiated area, with a figure of merit approaching 106 photons/s/MeV of deposited energy. Over a period of days, the singly charged O+ vacancies relax to the more stable doubly charged O++ vacancies. However, the overall defect PL returns to pre-irradiation values after about a week, as the vacancies diffuse to the surface of these very thin nanowires, indicating that a self-healing process restores the nanowires to their original state.

  2. Understanding the defect structure of solution grown zinc oxide

    SciTech Connect

    Liew, Laura-Lynn; Sankar, Gopinathan; Handoko, Albertus D.; Goh, Gregory K.L.; Kohara, Shinji

    2012-05-15

    Zinc oxide (ZnO) is a wide bandgap semiconducting oxide with many potential applications in various optoelectronic devices such as light emitting diodes (LEDs) and field effect transistors (FETs). Much effort has been made to understand the ZnO structure and its defects. However, one major issue in determining whether it is Zn or O deficiency that provides ZnO its unique properties remains. X-ray absorption spectroscopy (XAS) is an ideal, atom specific characterization technique that is able to probe defect structure in many materials, including ZnO. In this paper, comparative studies of bulk and aqueous solution grown ({<=}90 Degree-Sign C) ZnO powders using XAS and x-ray pair distribution function (XPDF) techniques are described. The XAS Zn-Zn correlation and XPDF results undoubtedly point out that the solution grown ZnO contains Zn deficiency, rather than the O deficiency that were commonly reported. This understanding of ZnO short range order and structure will be invaluable for further development of solid state lighting and other optoelectronic device applications. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer ZnO powders have been synthesized through an aqueous solution method. Black-Right-Pointing-Pointer Defect structure studied using XAS and XPDF. Black-Right-Pointing-Pointer Zn-Zn correlations are less in the ZnO powders synthesized in solution than bulk. Black-Right-Pointing-Pointer Zn vacancies are present in the powders synthesized. Black-Right-Pointing-Pointer EXAFS and XPDF, when used complementary, are useful characterization techniques.

  3. Adsorption of poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) polymers on zinc, zinc oxide, iron, and iron oxide surfaces.

    PubMed

    Seifert, Susan; Simon, Frank; Baumann, Giesela; Hietschold, Michael; Seifert, Andreas; Spange, Stefan

    2011-12-01

    The adsorption of poly(vinyl formamide) (PVFA) and the statistic copolymers poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) onto zinc and iron metal particles as well as their oxides was investigated. The adsorbates were characterized by means of XPS, DRIFT spectroscopy, wet chemical analysis, and solvatochromic probes. Dicyano-bis-(1,10-phenanthroline)-iron(II) (1), 3-(4-amino-3-methylphenyl)-7-phenyl-benzo-[1,2-b:4,5-b']difuran-2,6-dione (2), and 4-tert-butyl-2-(dicyano-methylene)-5-[4-(diethylamino)-benzylidene]-Δ(3)-thiazoline (3) as solvatochromic probes were coadsorbed onto zinc oxide to measure various effects of surface polarity. The experimental findings showed that the adsorption mechanism of PVFA and PVFA-co-PVAm strongly depends on the degree of hydrolysis of PVFA and pH values and also on the kind of metal or metal oxide surfaces that were employed as adsorbents. The adsorption mechanism of PVFA/PVFA-co-PVAm onto zinc oxide and iron oxide surfaces is mainly affected by electrostatic interactions. Particularly in the region of pH 5, the adsorption of PVFA/PVFA-co-PVAm onto zinc and iron metal particles is additionally influenced by redox processes, dissolution, and complexation reactions.

  4. Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer

    SciTech Connect

    El-Atab, Nazek; Rizk, Ayman; Nayfeh, Ammar; Okyay, Ali K.

    2013-11-15

    A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO{sub 2} layer is deposited between Atomic Layer Deposition (ALD) steps. A threshold voltage (V{sub t}) shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V V{sub t} shift, the memory with CrO{sub 2} layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO{sub 2} layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

  5. The influence of zinc chloride and zinc oxide nanoparticles on air-time survival in freshwater mussels.

    PubMed

    Gagné, François; Auclair, Joëlle; Peyrot, Caroline; Wilkinson, Kevin J

    2015-01-01

    The purpose of this study was to determine the cumulative effects of exposure to either dissolved zinc or nanozinc oxide (nanoZnO) and air-time survival in freshwater mussels. Mussels were exposed to each forms of zinc for 96h then placed in air to determine survival time. A sub-group of mussels before and after 7days of exposure to air were kept aside for the determination of the following biomarkers: arachidonate-dependent cyclooxygenase (COX) and peroxidase (inflammation and oxidative stress), lipid metabolism (total lipids, esterases activity, HO-glycerol, acetyl CoA and phospholipase A2) and lipid damage (lipid peroxidation [LPO]). The results showed that air-time survival was decreased from a mean value of 18.5days to a mean value of 12days in mussels exposed to 2.5mg/L of nanoZnO although it was not lethal based on shell opening at concentrations below 50mg/L after 96h. In mussels exposed to zinc only, the median lethal concentration was estimated at 16mg/L (10-25 95% CI). The air-time survival did not significantly change in mussels exposed to the same concentration of dissolved Zn. Significant weight losses were observed at 0.5mg/L of nanoZnO and at 2.5mg/L for dissolved zinc chloride, and were also significantly correlated with air-time survival (r=0.53; p<0.01). Air exposure significantly increased COX activity in control mussels and in mussels exposed to 0.5mg/L of nanoZnO and zinc chloride. The data also suggested fatty acid breakdown and β-oxidation. Mussels exposed to contaminants are more susceptible to prolonged exposure to air during low water levels.

  6. Zinc release from atomic layer deposited zinc oxide thin films and its antibacterial effect on Escherichia coli

    NASA Astrophysics Data System (ADS)

    Kääriäinen, M.-L.; Weiss, C. K.; Ritz, S.; Pütz, S.; Cameron, D. C.; Mailänder, V.; Landfester, K.

    2013-12-01

    Zinc oxide films have been grown by atomic layer deposition (ALD) at different reaction temperatures and in various thicknesses. Zinc-ion release has been examined from the ZnO films in water and in phosphate buffered saline solution (PBS). Additionally, the antibacterial effect has been studied on Escherichia coli. The thickness of the ZnO film or its crystal orientation did not affect the rate of dissolution. ALD grown aluminum oxide films were deposited on top of the ZnO films and they acted as an effective barrier against zinc dissolution. The bacteriostatic effect was not dependent on the film thickness but both 45 nm and 280 nm thick ZnO films significantly reduced bacterial attachment and growth in dark conditions by 99.7% and 99.5%, respectively. The results indicated that photoirradiation is not required for to enhance antibacterial properties of inorganic films and that the elution of zinc ions is probably responsible for the antibacterial properties of the ZnO films. The duration of the antibacterial effect of ZnO can be controlled by accurate control of the film thickness, which is a feature of ALD, and the onset of the antibacterial effect can be delayed by a time which can be adjusted by controlling the thickness of the Al2O3 blocking layer. This gives the possibility of obtaining dual antibacterial release profiles through a nanolaminate structure of these two materials.

  7. Rapid isolation of a facultative anaerobic electrochemically active bacterium capable of oxidizing acetate for electrogenesis and azo dyes reduction.

    PubMed

    Shen, Nan; Yuan, Shi-Jie; Wu, Chao; Cheng, Yuan-Yuan; Song, Xiang-Ning; Li, Wen-Wei; Tong, Zhong-Hua; Yu, Han-Qing

    2014-05-01

    In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source.

  8. Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications

    NASA Astrophysics Data System (ADS)

    Yuvakkumar, R.; Suresh, J.; Saravanakumar, B.; Joseph Nathanael, A.; Hong, Sun Ig; Rajendran, V.

    2015-02-01

    A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ∼40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4 days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48 h incubation with 7 days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.

  9. Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications.

    PubMed

    Yuvakkumar, R; Suresh, J; Saravanakumar, B; Joseph Nathanael, A; Hong, Sun Ig; Rajendran, V

    2015-02-25

    A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ∼40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4 days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48 h incubation with 7 days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.

  10. Dechlorination of Zinc Oxide Dust from Waelz Kiln by Microwave Roasting

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Zhang, Libo; Ma, Aiyuan; Peng, Jinhui; Li, Jing; Liu, Chenhui

    2015-05-01

    The new technology of dechlorination from zinc oxide dust by microwave roasting was investigated, combined with the advantages of microwave selective heating and based on a thermodynamic analysis of zinc and lead halides. The associated dechlorination reactions were discussed in details and the effect of all the influencing parameters such as roasting temperature, holding time, stirring speed and air flow were systematically investigated. Experimental results showed that zinc oxide dust dechlorination rate could reach over 95% and meet the requirements of wet smelting electrolysis, given an air flow of 300 L/h, a stirring speed of 60 r/min, a roasting temperature of 650 °C and a holding time of 30 min. Microwave roasting provided a new solution to the dechlorination from zinc oxide dust.

  11. Recovery of zinc from leach residues with minimum iron dissolution using oxidative leaching.

    PubMed

    Alizadeh, Reza; Rashchi, Fereshteh; Vahidi, Ehsan

    2011-02-01

    Leaching was performed to recover zinc from a zinc leach residue which contained 9.87% Zn and 4.93% Fe. During sulfuric acid leaching, Fe was dissolved as well as Zn which can reduce the Zn extraction efficiency. Leaching the residue in the presence of an oxidizing reagent such as hydrogen peroxide or manganese dioxide significantly reduced the iron content of the leach liquor. Effect of pH, temperature, solid/liquid ratio, reaction time and hydrogen peroxide or manganese dioxide concentration on the recovery of zinc and iron in non-oxidative and oxidative leaching conditions were investigated. By using the optimum oxidative leaching conditions, iron recovery reduced from 70% in non-oxidative leaching to 0.4 and 5% in the presence of MnO(2) and H(2)O(2), respectively, with acceptable Zn recovery. This reduction in the iron content was due to the different iron compounds formed at different conditions.

  12. Device performances of organic light-emitting diodes with indium tin oxide, gallium zinc oxide, and indium zinc tin oxide anodes deposited at room temperature.

    PubMed

    Lee, Changhun; Ko, Yoonduk; Kim, Youngsung

    2013-12-01

    Thin films of Indium tin oxide (ITO), Gallium zinc oxide (GZO), and Indium zinc tin oxide (IZTO) were deposited on glass substrates by pulsed direct current magnetron sputtering at room temperature. The structural, optical, and electrical properties of the films were investigated towards evaluating their applications as flexible anodes. IZTO films exhibited the lowest resistivity (6.3 x 10(-4) Omega cm). Organic light-emitting diodes (OLEDs) were fabricated using the ITO, GZO, and IZTO films as anode layers. The turn-on voltages at a current density of 4.5 mA/cm2, 5.5 mA/cm2, 6.5 mA/cm2 were 5.5 V, 13.7 V, and 4.7 V for the devices with ITO, GZO, and IZTO anodes, respectively. The best performance was observed with the IZTO film, indicating its suitability as an alternative material for conventional ITO anodes used in OLEDs and flexible displays. PMID:24266182

  13. Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.

    PubMed

    Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

    2013-03-01

    Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition.

  14. 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 ...

  15. 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.

  16. 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.

  17. 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

  18. Nanomolar concentrations of zinc pyrithione increase cell susceptibility to oxidative stress induced by hydrogen peroxide in rat thymocytes.

    PubMed

    Oyama, Tomohiro M; Saito, Minoru; Yonezawa, Takayasu; Okano, Yoshiro; Oyama, Yasuo

    2012-06-01

    Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 μM zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concentrations (10 nM or more) significantly increased the lethality of cells suffering from oxidative stress induced by 3 mM H(2)O(2). The application of zinc pyrithione alone at nanomolar concentrations increased intracellular Zn(2+) level and the cellular content of superoxide anions, and decreased the cellular content of nonprotein thiols. The simultaneous application of nanomolar zinc pyrithione and micromolar H(2)O(2) synergistically increased the intracellular Zn(2+) level. Therefore, zinc pyrithione at nanomolar concentrations may exert severe cytotoxic action on cells simultaneously exposed to chemicals that induce oxidative stress. If so, zinc pyrithione leaked from antifouling materials into surrounding environments would be a risk factor for aquatic ecosystems. Alternatively, zinc pyrithione under conditions of oxidative stress may become more potent antifouling ingredient. PMID:22356860

  19. Surface Functionalization of Oxide-Covered Zinc and Iron with Phosphonated Phenylethynyl Phenothiazine.

    PubMed

    Rechmann, Julian; Sarfraz, Adnan; Götzinger, Alissa C; Dirksen, Elena; Müller, Thomas J J; Erbe, Andreas

    2015-07-01

    Phenothiazines are redox-active, fluorescent molecules with potential applications in molecular electronics. Phosphonated phenylethynyl phenothiazine can be easily obtained in a four-step synthesis, yielding a molecule with a headgroup permitting surface linkage. Upon modifying hydroxylated polycrystalline zinc and iron, both covered with their respective native oxides, ultrathin organic layers were formed and investigated by use of infrared (IR) reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), contact angle measurement, and ellipsometry. While stable monolayers with upright oriented organic molecules were formed on oxide-covered iron, multilayer formation is observed on oxide-covered zinc. ToF-SIMS measurements reveal a bridging bidentate bonding state of the organic compound on oxide-covered iron, whereas monodentate complexes were observed on oxide-covered zinc. Both organically modified and unmodified surfaces exhibit reactive wetting, but organic modification makes the surfaces initially more hydrophobic. Cyclic voltammetry (CV) indicates redox activity of the multilayers formed on oxide-covered zinc. On the other hand, the monolayers on oxide-covered iron desorb after electrochemical modifications in the state of the oxide, but are stable at open circuit conditions. Exploiting an electronic coupling of phenothiazines to oxides may thus assist in corrosion protection.

  20. Zinc oxide nanoparticle induced genotoxicity in primary human epidermal keratinocytes.

    PubMed

    Sharma, Vyom; Singh, Suman K; Anderson, Diana; Tobin, Desmond J; Dhawan, Alok

    2011-05-01

    Zinc oxide (ZnO) nanoparticles are widely used in cosmetics and sunscreens. Human epidermal keratinocytes may serve as the first portal of entry for these nanoparticles either directly through topically applied cosmetics or indirectly through any breaches in the skin integrity. Therefore, the objective of the present study was to assess the biological interactions of ZnO nanoparticles in primary human epidermal keratinocytes (HEK) as they are the most abundant cell type in the human epidermis. Cellular uptake of nanoparticles was investigated by scanning electron microscopy using back scattered electrons imaging as well as transmission electron microscopy. The electron microscopy revealed the internalization of ZnO nanoparticles in primary HEK after 6 h exposure at 14 microg/ml concentration. ZnO nanoparticles exhibited a time (6-24 h) as well as concentration (8-20 microg/ml) dependent inhibition of mitochondrial activity as evident by the MTT assay. A significant (p < 0.05) induction in DNA damage was observed in cells exposed to ZnO nanoparticles for 6 h at 8 and 14 microg/ml concentrations compared to control as evident in the Comet assay. This is the first study providing information on biological interactions of ZnO nanoparticles with primary human epidermal keratinocytes. Our findings demonstrate that ZnO nanoparticles are internalized by the human epidermal keratinocytes and elicit a cytotoxic and genotoxic response. Therefore, caution should be taken while using consumer products containing nanoparticles as any perturbation in the skin barrier could expose the underlying cells to nanoparticles.

  1. Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure

    PubMed Central

    Kim, Yong Ho; Fazlollahi, Farnoosh; Kennedy, Ian M.; Yacobi, Nazanin R.; Hamm-Alvarez, Sarah F.; Borok, Zea; Kim, Kwang-Jin; Crandall, Edward D.

    2010-01-01

    Rationale: Although inhalation of zinc oxide (ZnO) nanoparticles (NPs) is known to cause systemic disease (i.e., metal fume fever), little is known about mechanisms underlying injury to alveolar epithelium. Objectives: Investigate ZnO NP–induced injury to alveolar epithelium by exposing primary cultured rat alveolar epithelial cell monolayers (RAECMs) to ZnO NPs. Methods: RAECMs were exposed apically to ZnO NPs or, in some experiments, to culture fluid containing ZnCl2 or free Zn released from ZnO NPs. Transepithelial electrical resistance (RT) and equivalent short-circuit current (IEQ) were assessed as functions of concentration and time. Morphologic changes, lactate dehydrogenase release, cell membrane integrity, intracellular reactive oxygen species (ROS), and mitochondrial activity were measured. Measurements and Main Results: Apical exposure to 176 μg/ml ZnO NPs decreased RT and IEQ of RAECMs by 100% over 24 hours, whereas exposure to 11 μg/ml ZnO NPs had little effect. Changes in RT and IEQ caused by 176 μg/ml ZnO NPs were irreversible. ZnO NP effects on RT yielded half-maximal concentrations of approximately 20 μg/ml. Apical exposure for 24 hours to 176 μg/ml ZnO NPs induced decreases in mitochondrial activity and increases in lactate dehydrogenase release, permeability to fluorescein sulfonic acid, increased intracellular ROS, and translocation of ZnO NPs from apical to basolateral fluid (most likely across injured cells and/or damaged paracellular pathways). Conclusions: ZnO NPs cause severe injury to RAECMs in a dose- and time-dependent manner, mediated, at least in part, by free Zn released from ZnO NPs, mitochondrial dysfunction, and increased intracellular ROS. PMID:20639441

  2. Curcumin Attenuates Hepatotoxicity Induced by Zinc Oxide Nanoparticles in Rats

    PubMed Central

    Khorsandi, Layasadat; Mansouri, Esrafil; Orazizadeh, Mahmoud; Jozi, Zahra

    2016-01-01

    Background: Zinc oxide nanoparticles (NZnO) are increasingly used in modern life. Most metal nanoparticles have adverse effects on the liver. Aims: To explore the protective action of curcumin (Cur) against hepatotoxicity induced by NZnO in rats. Study Design: Animal experimentation. Methods: Control group animals received normal saline, while the Cur group animals were treated with 200 mg/kg of Cur orally for 21 days. NZnO-intoxicated rats received 50 mg/kg of NZnO for 14 days by gavage method. In the NZnO+Cur group, rats were pretreated with Cur for 7 days before NZnO administration. Plasma activities of Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were measured as biomarkers of hepatotoxicity. Hepatic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured for detection of oxidative stress in liver tissue. Histological changes and apoptosis in liver tissue were studied by using Hematoxylin-eosin staining and the transferase dUTP nick end labeling (TUNEL) method. Results: NZnO induced a significant increase in plasma AST (2.8-fold), ALT (2.7-fold) and ALP (1.97-fold) activity in comparison to the control group (p<0.01). NZnO increased MDA content and reduced SOD and GPx activities. NZnO caused liver damage including centrilobular necrosis and microvesicular steatosis. The percentage of apoptosis in hepatocytes was increased in NZnO-treated rats (p<0.01). Pre-treatment of Cur significantly reduced lipid peroxidation (39%), increased SOD (156%) and GPx (26%) activities, and attenuated ALT (47%), AST (41%) and ALP (30%) activities. Pre-treatment with Cur also decreased the histology changes and apoptotic index of hepatocytes (p<0.05). Conclusion: These findings indicate that Cur effectively protects against NZnO-induced hepatotoxicity in rats. However, future studies are required to propose Cur as a potential protective agent against hepatotoxicity

  3. Hot gas desulfurization with oxides of zinc, iron, and vanadium

    SciTech Connect

    Akyurtlu, J.F.; Akyurtlu, A.

    1992-08-01

    The objective of this study is to develop an improved sorbent which can reduce H{sub 2}S levels up to 1 ppmv or less, which can stabilize zinc, and produce economically recoverable amounts of elemental sulfur during regeneration. For this purpose, the desulfurization performance of sorbents prepared by the addition of various amounts of V{sub 2}O{sub 5} to the zinc ferrite sorbent is investigated.

  4. 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

  5. Effects of crocin and zinc chloride on blood levels of zinc and metabolic and oxidative parameters in streptozotocin-induced diabetic rats

    PubMed Central

    Asri-Rezaei, Siamak; Tamaddonfard, Esmaeal; Ghasemsoltani-Momtaz, Behnaz; Erfanparast, Amir; Gholamalipour, Sima

    2015-01-01

    Objectives: Crocin is one of constituents of saffron and has antioxidant property. Zinc chloride is one of the common compounds of zinc with antioxidant activity. The present study was aimed to investigate separate and combined treatment effects of crocin and zinc chloride on blood levels of zinc and metabolic and oxidative parameters in diabetic rats. Materials and Methods: Diabetes was induced by intraperitoneal (i.p.) injection of 50 mg/kg of streptozotocin (STZ) and was confirmed by blood glucose levels higher than 250 mg/dL. After confirmation of diabetes, injections (i.p.) of crocin and zinc chloride were performed for six weeks. At the end of the experiment, blood levels of zinc, glucose, insulin, malodialdehyde (MDA), and total antioxidant capacity (TAC) were measured. ‎ Results: Crocin (25 and 50 mg/kg) and zinc chloride (5 mg/kg) significantly recovered the decreased levels of zinc, insulin, and TAC and improved the increased levels of glucose and MDA in STZ-induced diabetic rats. In a combination treatment performed with an ineffective dose of crocin (12.5 mg/kg) and a low dose of zinc chloride (1.25 mg/kg), improving effects were observed on the above-mentioned biochemical parameters.‎ Conclusion: The results indicated that separate and combined treatments with crocin and zinc chloride produced improving effects on the blood levels of zinc, glucose, insulin, MDA and TAC in STZ-induced diabetic rats. PMID:26468459

  6. Comparison of Calcium Phosphate and Zinc Oxide Nanoparticles as Dermal Penetration Enhancers for Albumin.

    PubMed

    Shokri, Narges; Javar, H A

    2015-01-01

    Dermal drug delivery is highly preferred by patients due to its several advantages. Protein therapeutics have attracted huge attention recently. Since dermal delivery of proteins encounter problems, in this investigation, zinc oxide nanoparticles and calcium phosphate nanoparticles were compared as enhancers for dermal permeation of albumin. Albumin was applied simultaneously with zinc oxide nanoparticles or calcium phosphate nanoparticles on pieces of mouse skin. Skin permeation of albumin over time was determined using a diffusion cell. Skin distribution of the nanoparticles and albumin over time was determined by optical and fluorescence microscopy. Zinc oxide nanoparticles and calcium phosphate nanoparticles acted as enhancers for skin permeation of albumin. Cumulative permeated albumin in presence of zinc oxide nanoparticles after 0, 0.5, 1, 1.5 and 2 h, were 0±0, 11.7±3.3, 21.1±3.5, 40.2±3.6 and 40.2±3.6 mg, respectively and in presence of calcium phosphate nanoparticles were 0±0, 20.9±7.4, 33.8±5.5, 33.8±3.7 and 33.8±3.7 mg, respectively. After 0.5 h, little amount of albumin was permeated in presence of every kind of the nanoparticles. After 0.5 or 1 h, the permeated albumin in presence of calcium phosphate nanoparticles was more than that in presence of zinc oxide nanoparticles and after 1.5 h the permeated albumin in presence of zinc oxide nanoparticles was more than that in presence of calcium phosphate nanoparticles. Images of skin distribution of the two nanoparticles over time, were somewhat different and distribution of albumin correlated with the distribution of the nanoparticles alone. The profiles of albumin permeation (in presence of each of the nanoparticles) versus time was delayed and linear for both nanoparticles while the slope for calcium phosphate nanoparticles was higher than zinc oxide nanoparticles. The enhancer effect of zinc oxide nanoparticles was stronger while the enhancer effect of calcium phosphate nanoparticles was

  7. Solubility of nano-zinc oxide in environmentally and biologically important matrices

    PubMed Central

    Reed, Robert B.; Ladner, David A.; Higgins, Christopher P.; Westerhoff, Paul; Ranville, James F.

    2011-01-01

    Increasing manufacture and use of engineered nanoparticles (NPs) is leading to a greater probability for release of ENPs into the environment and exposure to organisms. In particular, zinc oxide (ZnO) is toxic, although it is unclear whether this toxicity is due to the zinc oxide nanoparticles (ZnO), dissolution to Zn2+, or some combination thereof. The goal of this study was to determine the relative solubilites of both commercially available and in-house synthesized ZnO in matrices used for environmental fate and transport or biological toxicity studies. Dissolution of ZnO was observed in nanopure water (7.18– 7.40 mg/L dissolved Zn, as measured by filtration) and Roswell Park Memorial Institute medium (RPMI-1640) (~5 mg/L), but much more dissolution was observed in Dulbecco’s Modified Eagle’s Medium (DMEM), where the dissolved Zn concentration exceeded 34 mg/L. Moderately hard water exhibited low zinc solubility, likely due to precipitation of a zinc carbonate solid phase. Precipitation of a zinc-containing solid phase in RPMI also appeared to limit zinc solubility. Equilibrium conditions with respect to ZnO solubility were not apparent in these matrices, even after more than 1,000 h of dissolution. These results suggest that solution chemistry exerts a strong influence on ZnO dissolution and can result in limits on zinc solubility due to precipitation of less soluble solid phases. PMID:21994124

  8. 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.

  9. Enhanced ionic polymer metal composite actuator with porous nafion membrane using zinc oxide particulate leaching method

    NASA Astrophysics Data System (ADS)

    Jung, Sun Yong; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-03-01

    In this study, to improve the performance of an ionic polymer metal composite (IPMC), we suggest a porous nafion membrane fabricated with the particulate leaching method with zinc oxide and propose an IPMC that uses the porous nafion membrane. To fabricate this membrane, the proper ratio of nafion and zinc oxide powder is dispersed in a solvent. Then the zinc oxide embedded in the nafion membrane is fabricated with a casting method. With the particulate leaching method, the embedded zinc oxide particles are dissolved by an acid solution, and the spaces of the zinc oxide particles changed to pores. Finally, through electroless plating and ion exchange procedures, an IPMC with the porous nafion membrane is fabricated. The proposed IPMC has higher water uptake (WUP) and ion exchange capacity (IEC) and can show better actuation performance compared to the conventional nafion-based IPMC. We also measure the actuation displacement and blocking forces of the proposed IPMC. Compared with the conventional nafion-based IPMC, the proposed IPMC with the porous nafion membrane has increased displacements: about 80% at ac input and about 250% at dc input, and increased blocking force about 130% at dc input.

  10. Antidiabetic activity of zinc oxide and silver nanoparticles on streptozotocin-induced diabetic rats.

    PubMed

    Alkaladi, Ali; Abdelazim, Aaser Mohamed; Afifi, Mohamed

    2014-01-01

    The use of nanoparticles in medicine is an attractive proposition. In the present study, zinc oxide and silver nanoparticles were evaluated for their antidiabetic activity. Fifty male albino rats with weight 120 ± 20 and age 6 months were used. Animals were grouped as follows: control; did not receive any type of treatment, diabetic; received a single intraperitoneal dose of streptozotocin (100 mg/kg), diabetic + zinc oxide nanoparticles (ZnONPs), received single daily oral dose of 10 mg/kg ZnONPs in suspension, diabetic + silver nanoparticles (SNPs); received a single daily oral dose of SNP of 10 mg/kg in suspension and diabetic + insulin; received a single subcutaneous dose of 0.6 units/50 g body weight. Zinc oxide and silver nanoparticles induce a significant reduced blood glucose, higher serum insulin, higher glucokinase activity higher expression level of insulin, insulin receptor, GLUT-2 and glucokinase genes in diabetic rats treated with zinc oxide, silver nanoparticles and insulin. In conclusion, zinc oxide and sliver nanoparticles act as potent antidiabetic agents. PMID:24477262

  11. AZO thin film-based UV sensors: effects of RF power on the films

    NASA Astrophysics Data System (ADS)

    Akin, Nihan; Ceren Baskose, U.; Kinaci, Baris; Cakmak, Mehmet; Ozcelik, Suleyman

    2015-06-01

    Al-doped zinc oxide (AZO) thin films of thickness 150 nm were deposited on polyethylene terephthalate (PET) substrates by radio frequency (RF) magnetron sputtering method under various RF powers in the range of 25-100 W. Structural, morphological, optical and electrical properties of the films were investigated by X-ray diffractometer, atomic force microscope, UV-Vis spectrometer and Hall effect measurement system. All the obtained films had a highly preferred orientation along [002] direction of the c-axis perpendicular to the flexible PET substrate and had a high-quality surface. The energy band gap ( E g) values of the films varied in the range of 3.30-3.43 eV. The minimum resistivity of 1.84 × 10-4 Ω cm was obtained at a 50 W RF power. The small changes in the RF power had a critical important role on the structural, optical and electrical properties of the sputtered AZO thin films on flexible PET substrate. In addition, UV sensing of the fabricated AZO thin film-based sensors was explored by using current-voltage (I-V) characteristics. The sensors were sensitive in the UV region of the electromagnetic spectrum.

  12. Heterogeneous electro-Fenton oxidation of azo dye methyl orange catalyzed by magnetic Fe3O4 nanoparticles.

    PubMed

    Jiang, Hao; Sun, Yabing; Feng, Jingwei; Wang, Jian

    2016-01-01

    Azo dye methyl orange (MO) degradation by heterogeneous electro-Fenton (EF) with a magnetic nano-Fe3O4 catalyst was investigated. In this study, Fe3O4 was synthesized by a coprecipitation method and characterized by X-ray diffraction and scanning electron microscopy. The influences of the main operating parameters such as current density, pH, catalyst dosage and aeration rate were studied. The results revealed that higher current density, catalyst dosage and aeration rate facilitated the degradation of MO, whereas the degradation efficiency of MO was decreased with an increase in the initial pH. After 90 min EF process, the volume of 500 mL, the initial concentration of 50 mg L(-1) MO solution could be degraded by 86.6% with the addition of 1 g L(-1) Fe3O4 under the current density of 10 mA cm(-2) and pH 3, compared with 69.5% for the electrolytic process alone. Meanwhile, a total organic carbon removal of 32% was obtained, up to 35.5 mg L(-1) accumulated H2O2 and less than 3.5 mg L(-1) Fe leaching were detected. Moreover, based on the results of natural bond orbital (at B3LYP/6-311G (d, p)) and liquid chromatograph-triple quadrupole mass spectrometer analysis, nine intermediates were identified and the proposed degradation pathways were investigated. PMID:27642831

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

    NASA Astrophysics Data System (ADS)

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

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

  14. Sorption behavior of microamounts of zinc on titanium oxide from aqueous solutions

    SciTech Connect

    Hasany, S.M.; Ghaffar, A. ); Chughtai, F.A. )

    1991-08-01

    To correlate soil response toward zinc, it is necessary to study its adsorption in detail on soils or on their constituents. The adsorption of microamounts of zinc on titanium oxide, prepared and characterized in this laboratory, has been studied in detail. Zinc adsorption has been found to be dependent on the pH of the aqueous solution, amount of oxide, and zinc concentration. Maximum adsorption is from pH 10 buffer. EDTA and cyanide ions inhibit adsorption significantly. The adsorption of other elements under optimal conditions has also been measured on this oxide. Sc(III) and Cs(I) show almost negligible adsorption. Zinc adsorption follows the linear form of the Freundlich adsorption isotherm: log C{sub Ads} = log A + (1/n) log C{sub Bulk} with A = 0.48 mol/g and n = 1. Except at a very low bulk concentration (3 {times} 10{sup {minus}5} mol/dm{sup 3}), Langmuir adsorption isotherm is also linear for the entire zinc concentration investigated. The limiting adsorbed concentration is estimated to be 0.18 mol/g.

  15. Zinc (hydr)oxide/graphite oxide/AuNPs composites: role of surface features in H₂S reactive adsorption.

    PubMed

    Giannakoudakis, Dimitrios A; Bandosz, Teresa J

    2014-12-15

    Zinc hydroxide/graphite oxide/AuNPs composites with various levels of complexity were synthesized using an in situ precipitation method. Then they were used as H2S adsorbents in visible light. The materials' surfaces were characterized before and after H2S adsorption by various physical and chemical methods (XRD, FTIR, thermal analysis, potentiometric titration, adsorption of nitrogen and SEM/EDX). Significant differences in surface features and synergistic effects were found depending on the materials' composition. Addition of graphite oxide and the deposition of gold nanoparticles resulted in a marked increase in the adsorption capacity in comparison with that on the zinc hydroxide and zinc hydroxide/AuNP. Addition of AuNPs to zinc hydroxide led to a crystalline ZnO/AuNP composite while the zinc hydroxide/graphite oxide/AuNP composite was amorphous. The ZnOH/GO/AuNPs composite exhibited the greatest H2S adsorption capacity due to the increased number of OH terminal groups and the conductive properties of GO that facilitated the electron transfer and consequently the formation of superoxide ions promoting oxidation of hydrogen sulfide. AuNPs present in the composite increased the conductivity, helped with electron transfer to oxygen, and prevented the fast recombination of the electrons and holes.

  16. Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry.

    PubMed

    Jiang, Chuanjia; Hsu-Kim, Heileen

    2014-11-01

    The wide use of metal-based nanomaterials such as zinc oxide (ZnO) nanoparticles (NPs) has generated concerns regarding their environmental and health risks. For ZnO NPs, their toxicity in aquatic systems often depends on the release of dissolved zinc species, and the rate of dissolution is influenced by water chemistry, including the presence of zinc-chelating ligands. A challenge, however, remains in quantifying the dissolution of ZnO NPs, particularly for time scales that are short enough to determine rates. This paper reports the application of anodic stripping voltammetry (ASV) with a hanging mercury drop electrode to directly measure the concentration of dissolved zinc in ZnO NP suspensions, without separation of the ZnO NPs from the aqueous phase. The effects of the deposition time and the electrochemical potential scan rate on the ASV measurement were consistent with expectations for dissolved phase measurements. The dissolved zinc concentration measured by ASV ([Zn]ASV) was compared with that measured by inductively coupled plasma mass spectrometry (ICP-MS) after ultracentrifugation ([Zn]ICP-MS), for four types of ZnO NPs with different coatings and primary particle diameters. For small ZnO NPs (4-5 nm), [Zn]ASV was 20% higher than [Zn]ICP-MS, suggesting that these small NPs contributed to the voltammetric measurement. For larger ZnO NPs (approximately 20 nm), [Zn]ASV was (79 ± 19)% of [Zn]ICP-MS, despite the high concentrations of ZnO NPs in suspension. Using ASV, the dissolution of ZnO NPs was studied, with or without Suwannee River Fulvic Acid (SRFA). Although SRFA diminished the ASV stripping current, dissolution of 20 nm ZnO NPs was significantly promoted at high fulvic acid to ZnO NP ratios. The ASV method described in this paper provides a useful tool for studying the dissolution kinetics of ZnO NPs in complex environmental matrices.

  17. Zinc Oxide Nanoparticles Affect Biomass Accumulation and Photosynthesis in Arabidopsis.

    PubMed

    Wang, Xiaoping; Yang, Xiyu; Chen, Siyu; Li, Qianqian; Wang, Wei; Hou, Chunjiang; Gao, Xiao; Wang, Li; Wang, Shucai

    2015-01-01

    Dramatic increase in the use of nanoparticles (NPs) in a variety of applications greatly increased the likelihood of the release of NPs into the environment. Zinc oxide nanoparticles (ZnO NPs) are among the most commonly used NPs, and it has been shown that ZnO NPs were harmful to several different plants. We report here the effects of ZnO NPs exposure on biomass accumulation and photosynthesis in Arabidopsis. We found that 200 and 300 mg/L ZnO NPs treatments reduced Arabidopsis growth by ∼20 and 80%, respectively, in comparison to the control. Pigments measurement showed that Chlorophyll a and b contents were reduced more than 50%, whereas carotenoid contents remain largely unaffected in 300 mg/L ZnO NPs treated Arabidopsis plants. Consistent with this, net rate of photosynthesis, leaf stomatal conductance, intercellular CO2 concentration and transpiration rate were all reduced more than 50% in 300 mg/L ZnO NPs treated plants. Quantitative RT-PCR results showed that expression levels of chlorophyll synthesis genes including CHLOROPHYLL A OXYGENASE (CAO), CHLOROPHYLL SYNTHASE (CHLG), COPPER RESPONSE DEFECT 1 (CRD1), MAGNESIUM-PROTOPORPHYRIN IX METHYLTRANSFERASE (CHLM) and MG-CHELATASE SUBUNIT D (CHLD), and photosystem structure gene PHOTOSYSTEM I SUBUNIT D-2 (PSAD2), PHOTOSYSTEM I SUBUNIT E-2 (PSAE2), PHOTOSYSTEM I SUBUNIT K (PSAK) and PHOTOSYSTEM I SUBUNIT K (PSAN) were reduced about five folds in 300 mg/L ZnO NPs treated plants. On the other hand, elevated expression, though to different degrees, of several carotenoids synthesis genes including GERANYLGERANYL PYROPHOSPHATE SYNTHASE 6 (GGPS6), PHYTOENE SYNTHASE (PSY) PHYTOENE DESATURASE (PDS), and ZETA-CAROTENE DESATURASE (ZDS) were observed in ZnO NPs treated plants. Taken together, these results suggest that toxicity effects of ZnO NPs observed in Arabidopsis was likely due to the inhibition of the expression of chlorophyll synthesis genes and photosystem structure genes, which results in the inhibition of

  18. Zinc Oxide Nanoparticles Affect Biomass Accumulation and Photosynthesis in Arabidopsis

    PubMed Central

    Wang, Xiaoping; Yang, Xiyu; Chen, Siyu; Li, Qianqian; Wang, Wei; Hou, Chunjiang; Gao, Xiao; Wang, Li; Wang, Shucai

    2016-01-01

    Dramatic increase in the use of nanoparticles (NPs) in a variety of applications greatly increased the likelihood of the release of NPs into the environment. Zinc oxide nanoparticles (ZnO NPs) are among the most commonly used NPs, and it has been shown that ZnO NPs were harmful to several different plants. We report here the effects of ZnO NPs exposure on biomass accumulation and photosynthesis in Arabidopsis. We found that 200 and 300 mg/L ZnO NPs treatments reduced Arabidopsis growth by ∼20 and 80%, respectively, in comparison to the control. Pigments measurement showed that Chlorophyll a and b contents were reduced more than 50%, whereas carotenoid contents remain largely unaffected in 300 mg/L ZnO NPs treated Arabidopsis plants. Consistent with this, net rate of photosynthesis, leaf stomatal conductance, intercellular CO2 concentration and transpiration rate were all reduced more than 50% in 300 mg/L ZnO NPs treated plants. Quantitative RT-PCR results showed that expression levels of chlorophyll synthesis genes including CHLOROPHYLL A OXYGENASE (CAO), CHLOROPHYLL SYNTHASE (CHLG), COPPER RESPONSE DEFECT 1 (CRD1), MAGNESIUM-PROTOPORPHYRIN IX METHYLTRANSFERASE (CHLM) and MG-CHELATASE SUBUNIT D (CHLD), and photosystem structure gene PHOTOSYSTEM I SUBUNIT D-2 (PSAD2), PHOTOSYSTEM I SUBUNIT E-2 (PSAE2), PHOTOSYSTEM I SUBUNIT K (PSAK) and PHOTOSYSTEM I SUBUNIT K (PSAN) were reduced about five folds in 300 mg/L ZnO NPs treated plants. On the other hand, elevated expression, though to different degrees, of several carotenoids synthesis genes including GERANYLGERANYL PYROPHOSPHATE SYNTHASE 6 (GGPS6), PHYTOENE SYNTHASE (PSY) PHYTOENE DESATURASE (PDS), and ZETA-CAROTENE DESATURASE (ZDS) were observed in ZnO NPs treated plants. Taken together, these results suggest that toxicity effects of ZnO NPs observed in Arabidopsis was likely due to the inhibition of the expression of chlorophyll synthesis genes and photosystem structure genes, which results in the inhibition of

  19. Photocatalytic degradation of organochlorine compounds over titanium oxide and titanium oxide containing zinc oxide decatungstate and hydrogen peroxide

    SciTech Connect

    Sattari, D.

    1995-12-01

    Ten organochlorine solvents, commonly used in industry, which are di- tri- and tetra- chloro derivatives of methane, ethane and ethylene were photocatalytically degraded over titanium oxide and titanium oxide containing zinc oxide: decatungstate and hydrogen peroxide. The study has been carried out by determining the yield of organochlorine degradation at different irradiation time. It was found that for derivatives of the three compounds the degradation rates were in the order of di>tri>tetra and for those containing the same number of chlorine substituents the order was ethylene>ethane. During the degradation of each organochlorine solvent chloride was liberated. Stoichiometry for photocatalytic degradation of organochlorine solvents are C{sub x}H{sub y-z}Cl{sub z} + xO{sub 2}{yields}xCO{sub 2} + (y-z)H{sup +} + zCl{sup -}.

  20. Synthesis and characterization of zinc oxide-neem oil-chitosan bionanocomposite for food packaging application.

    PubMed

    Sanuja, S; Agalya, A; Umapathy, M J

    2015-03-01

    Nano zinc oxide at different concentrations (0.1, 0.3 and 0.5%) and neem essential oil were incorporated into the chitosan polymer by solution cast method to enhance the properties of the bionanocomposite film. The functional groups, crystalline particle size, thermal stability and morphology were determined using FTIR, XRD, TGA and SEM, respectively. The results showed that 0.5% nano zinc oxide incorporated composite film have improved tensile strength, elongation, film thickness, film transparency and decreased water solubility, swelling and barrier properties due to the presence of neem oil and nano zinc oxide in the polymer matrix. Further antibacterial activity by well diffusion assay method was followed against Escherichia coli which were found to have good inhibition effect. In addition to this food quality application were carried against carrot and compared with the commercial film.

  1. Epitaxial aluminum-doped zinc oxide thin films on sapphire. 1: Effect of substrate orientation

    SciTech Connect

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

    1995-07-01

    Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated using on- and off-axis X-ray diffractometry. Under all growth conditions zinc oxide, on A- and C-plane sapphire, grew with the c-axis perpendicular to the substrate. In contrast, on M and R orientations of sapphire, ZnO grew with its c-axis parallel or perpendicular to the substrate depending on the substrate temperature and background pressure employed during growth. In all cases only one unique in-plane relationship between the sapphire substrate and the zinc oxide film was found with the exception of the M-plane at high substrate temperatures.

  2. Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria

    NASA Astrophysics Data System (ADS)

    Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

    2013-11-01

    The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 μg mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.

  3. Synthesis and characterization of zinc oxide-neem oil-chitosan bionanocomposite for food packaging application.

    PubMed

    Sanuja, S; Agalya, A; Umapathy, M J

    2015-03-01

    Nano zinc oxide at different concentrations (0.1, 0.3 and 0.5%) and neem essential oil were incorporated into the chitosan polymer by solution cast method to enhance the properties of the bionanocomposite film. The functional groups, crystalline particle size, thermal stability and morphology were determined using FTIR, XRD, TGA and SEM, respectively. The results showed that 0.5% nano zinc oxide incorporated composite film have improved tensile strength, elongation, film thickness, film transparency and decreased water solubility, swelling and barrier properties due to the presence of neem oil and nano zinc oxide in the polymer matrix. Further antibacterial activity by well diffusion assay method was followed against Escherichia coli which were found to have good inhibition effect. In addition to this food quality application were carried against carrot and compared with the commercial film. PMID:25499891

  4. BIOCHEMISTRY OF MOBILE ZINC AND NITRIC OXIDE REVEALED BY FLUORESCENT SENSORS

    PubMed Central

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

    2010-01-01

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

  5. Diffusion Coefficients of n-Alkanes and Polyethylenes Filled with Zinc Oxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Ozisik, Rahmi; Mattice, Wayne L.; von Meerwall, Ernst

    2003-03-01

    The diffusion coefficients of various n-alkane and polyethylene samples filled with zinc oxide nanoparticles were measured with pulsed-gradient spin-echo (PGSE) NMR technique. The n-alkanes used in this study had carbon numbers ranging between 12 and 60. The number average molecular weights of the two polyethylene samples were 6200 and 13900 g/mol. The different size of zinc oxide used with spherical geometry. The experiments were performed with three different zinc oxide nanoparticles that had differing sizes. This study investigates the effects of the nanoparticle size and the molecular weight on the diffusion coefficient of the polymer chains. The results account for the restriction to diffusion due to detour and tortuosity effects, which differ for n-alkanes and polyethylene. Because the effective diffusion distance in the PGSE NMR experiments is larger than the size of the nanoparticles, the observed diffusivities represent asymptotic averages over multiple encounters between the diffusing molecules and the nanoparticles.

  6. The role of intracellular zinc in chromium(VI)-induced oxidative stress, DNA damage and apoptosis.

    PubMed

    Rudolf, Emil; Cervinka, Miroslav

    2006-09-25

    Several studies have demonstrated that zinc is required for the optimal functioning of the skin. Changes in intracellular zinc concentrations have been associated with both improved protection of skin cells against various noxious factors as well as with increased susceptibility to external stress. Still, little is known about the role of intracellular zinc in hexavalent chromium (Cr(VI))-induced skin injury. To address this question, the effects of zinc deficiency or supplementation on Cr(VI)-induced cytotoxicity, oxidative stress, DNA injury and cell death were investigated in human diploid dermal fibroblasts during 48 h. Zinc levels in fibroblasts were manipulated by pretreatment of cells with 100 microM ZnSO4 and 4 or 25 microM zinc chelator TPEN. Cr(VI) (50, 10 and 1 microM) was found to produce time- and dose-dependent cytotoxicity resulting in oxidative stress, suppression of antioxidant systems and activation of p53-dependent apoptosis which is reported for the first time in this model in relation to environmental Cr(VI). Increased intracellular zinc partially attenuated Cr(VI)-induced cytotoxicity, oxidative stress and apoptosis by enhancing cellular antioxidant systems while inhibiting Cr(VI)-dependent apoptosis by preventing the activation of caspase-3. Decreased intracellular zinc enhanced cytotoxic effects of all the tested Cr(VI) concentrations, leading to rapid loss of cell membrane integrity and nuclear dispersion--hallmarks of necrosis. These new findings suggest that Cr(VI) as a model environmental toxin may damage in deeper regions residing skin fibroblasts whose susceptibility to such toxin depends among others on their intracellular Zn levels. Further investigation of the impact of Zn status on skin cells as well as any other cell populations exposed to Cr(VI) or other heavy metals is warranted.

  7. Spectroscopic characterization of zinc oxide nanorods synthesized by solid-state reaction

    NASA Astrophysics Data System (ADS)

    Prasad, Virendra; D'Souza, Charlene; Yadav, Deepti; Shaikh, A. J.; Vigneshwaran, Nadanathangam

    2006-09-01

    Well-crystallized zinc oxide nanorods have been fabricated by single step solid-state reaction using zinc acetate and sodium hydroxide, at room temperature. The sodium lauryl sulfate (SLS) stabilized zinc oxide nanorods were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectroscopy. The X-ray diffraction revealed the wurtzite structure of zinc oxide. The size estimation by XRD and TEM confirmed that the ZnO nanorods are made of single crystals. The growth of zinc oxide crystals into rod shape was found to be closely related to its hexagonal nature. The mass ratio of SLS:ZnO in the nanorods was found to be 1:10 based on the thermogravimetric analysis. Blue shift of photoluminescence emission was noticed in the ZnO nanorods when compared to that of ZnO bulk. FT-IR analysis confirmed the binding of SLS with ZnO nanorods. Apart from ease of preparation, this method has the advantage of eco-friendliness since the solvent and other harmful chemicals were eliminated in the synthesis protocol.

  8. Teucrium polium L. extract adsorbed on zinc oxide nanoparticles as a fortified sunscreen

    PubMed Central

    Ansari, Mehdi; Sharififar, Fariba; Kazemipour, Maryam; Sarhadinejad, Zarrin; Mahdavi, Hamid

    2013-01-01

    Introduction: Zinc oxide nanoparticles (ZnOn) have been used as carriers and sun-protecting agents for Teucrium polium L. extract to enhance sun protection. ZnOn was synthesized by hydrolyzing zinc acetate using sodium hydroxide with mean particle diameter less than 500 nm. Materials and Methods: Top flowerings of T. polium L. were extracted by percolation method with petroleum ether, chloroform, and 80% methanol consecutively. Methanolic extract was lyophilized and used as a flavonoid-rich fraction. Sunscreen was prepared by the reconstitution of 0.5 g of the lyophilized extract in water and mixing with 0.5 to 2 g zinc-oxide (ZnO). Sun protection factor (SPF) of the aqueous extract of T. polium, the prepared gel, as well as the zinc oxide suspension alone and in combination with each other was determined spectrophotometrically based on a modified Transpore® tape method. Results and Conclusion: Obtained results showed that the T. polium extract has a wide band of ultraviolet radiation (UV) spectrum absorption ranging from 250 nm to 380 nm. SPF of the combination product in the ultraviolet B (UVB) area was greater than 80, revealing a synergistic action between ZnO and T. polium. The adsorption of flavonoids of T. polium on Zinc-oxide nanoparticles (ZnOn) slowed down their release thereby lengthening their persistence on the skin and contributing to further duration of action. PMID:24350038

  9. Examination of the Oxidation Protection of Zinc Coatings Formed on Copper Alloys and Steel Substrates

    NASA Astrophysics Data System (ADS)

    Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.

    2010-01-01

    The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

  10. EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES

    SciTech Connect

    Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.

    2010-01-21

    The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

  11. Degradation efficiencies of azo dye Acid Orange 7 by the interaction of heat, UV and anions with common oxidants: persulfate, peroxymonosulfate and hydrogen peroxide.

    PubMed

    Yang, Shiying; Wang, Ping; Yang, Xin; Shan, Liang; Zhang, Wenyi; Shao, Xueting; Niu, Rui

    2010-07-15

    In this paper, the degradation of azo dye Acid Orange 7 (AO7) by three common peroxides (persulfate (PS), peroxymonosulfate (PMS) or hydrogen peroxide (H(2)O(2))) under various activation conditions, i.e., heat (25-80 degrees C), UV light (254 nm), or anions (SO(4)(2-), NO(3)(-), CO(3)(2-), HCO(3)(-), HPO(4)(2-), and Cl(-)), was investigated. The order of AO7 degradation efficiencies by heat activation is PS>PMS>H(2)O(2). PS oxidation activated by heat (>50 degrees C) is an effective degradation technology, while PMS and H(2)O(2) are hardly activated. When assisted by UV, peroxides could all be activated and degrade AO7 quickly. The order is PS>H(2)O(2)>PMS. We activated peroxides, for the first time, by using some anions and compared the subsequently degradation efficiencies of AO7. It was found that PMS could be activated by some anions, but PS and H(2)O(2) cannot. The activation efficiencies of PMS by SO(4)(2-) and NO(3)(-) are negligible, whereas remarkable by HCO(3)(-), HPO(4)(2-), Cl(-) and CO(3)(2-). For HCO(3)(-), HPO(4)(2-) and Cl(-), the activation efficiencies become higher with the increase of anion concentration. For CO(3)(2-), however, the activation efficiency is higher at lower concentration.

  12. 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

  13. 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

  14. Using C₆₀⁺ Sputtering to Improve Detection Limit of Nitrogen in Zinc Oxide

    SciTech Connect

    Zhu, Zihua; Shutthanandan, V.; Nachimuthu, Ponnusamy

    2010-05-11

    C₆₀⁺ sputtering was firstly used to determine depth profile of nitrogen in zinc oxide materials by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Compared to traditional Cs+ sputtering depth profiling, the C₆₀⁺ sputtering provides over 200 times of effective signal intensity and the detection limit is about 10 times better. In addition, our X-ray photoelectron spectroscopy (XPS) results show that sputtering zinc oxide materials by 10 keV C₆₀⁺ leads to very weak carbon deposition at bottom of the sputter crater.

  15. Synthesis, characterization and antimicrobial applications of zinc oxide nanoparticles loaded gum acacia/poly(SA) hydrogels.

    PubMed

    Bajpai, S K; Jadaun, Mamta; Tiwari, Seema

    2016-11-20

    In this work, zinc oxide nanoparticles were synthesized in-situ within the gum acacia/poly (acrylate) hydrogel network using hydrothermal approach. The synthesized zinc oxide nanoparticles were characterized by Surface plasmon resonance (SPR), X-Ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM). The water absorption behavior of ZnO/GA/poly(SA) hydrogels was investigated in the phosphate buffer saline (PBS) of pH 7.4 at 37°C. The water uptake data were analyzed with the help of various kinetic models. Finally, the antimicrobial action of nanocomposites was studied using E. coli as model bacteria.

  16. Eco-friendly approach towards green synthesis of zinc oxide nanocrystals and its potential applications.

    PubMed

    Velmurugan, Palanivel; Park, Jung-Hee; Lee, Sang-Myeong; Yi, Young-Joo; Cho, Min; Jang, Jum-Suk; Myung, Hyun; Bang, Keuk-Soo; Oh, Byung-Taek

    2016-09-01

    In the present study, we investigated a novel green route for synthesis of zinc oxide (ZnO) nanocrystals using Prunus × yedoensis Matsumura leaf extract as a reducing agent without using any surfactant or external energy. Standard characterization studies were carried out to confirm the obtained product using UV-Vis spectra, SEM-EDS, FTIR, TEM, and XRD. In addition, the synthesized ZnO nanocrystals were coated onto fabric and leather samples to study their bacteriostatic effect against odor-causing bacteria Brevibacterium linens and Staphylococcus epidermidis. Zinc oxide nanocrystal-coated fabric and leather showed good activity against both bacteria.

  17. Controlled Growth of one-dimensional zinc oxide nanostructures in the pulsed electrodeposition mode

    SciTech Connect

    Klochko, N. P. Khrypunov, G. S.; Myagchenko, Yu. O.; Melnychuk, E. E.; Kopach, V. R.; Klepikova, E. S.; Lyubov, V. M.; Kopach, A. V.

    2012-06-15

    Zinc oxide nanostructures are objects of study in the field of optoelectronics, solar power engineering, nanosensorics, and catalysis. For the purpose of the controlled growth of one-dimensional submicrometer zinc oxide structures in the pulsed electrodeposition mode, the effect of the pulse electrolysis parameters on the morphology of ZnO layers, their optical properties, and structural and substructural characteristics is determined using X-ray diffraction, optical spectrophotometry, and atomic-force microscopy. The possibility of fabricating arrays of ZnO nanowires with different geometrical shapes, perpendicular to the substrate surface, by varying the frequency of cathode-substrate potential pulses is shown.

  18. Synthesis, characterization and antimicrobial applications of zinc oxide nanoparticles loaded gum acacia/poly(SA) hydrogels.

    PubMed

    Bajpai, S K; Jadaun, Mamta; Tiwari, Seema

    2016-11-20

    In this work, zinc oxide nanoparticles were synthesized in-situ within the gum acacia/poly (acrylate) hydrogel network using hydrothermal approach. The synthesized zinc oxide nanoparticles were characterized by Surface plasmon resonance (SPR), X-Ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM). The water absorption behavior of ZnO/GA/poly(SA) hydrogels was investigated in the phosphate buffer saline (PBS) of pH 7.4 at 37°C. The water uptake data were analyzed with the help of various kinetic models. Finally, the antimicrobial action of nanocomposites was studied using E. coli as model bacteria. PMID:27561472

  19. In vivo target bio-imaging of Alzheimer's disease by fluorescent zinc oxide nanoclusters.

    PubMed

    Lai, Lanmei; Zhao, Chunqiu; Su, Meina; Li, Xiaoqi; Liu, Xiaoli; Jiang, Hui; Amatore, Christian; Wang, Xuemei

    2016-07-21

    Alzheimer's disease (AD) is an irreversible neurodegenerative disease which is difficult to cure. When Alzheimer's disease occurs, the level of zinc ions in the brain changes, and the relevant amount of zinc ions continue decreasing in the cerebrospinal fluid and plasma of Alzheimer's patients with disease exacerbation. In view of these considerations, we have explored a new strategy for the in vivo rapid fluorescence imaging of Alzheimer's disease through target bio-labeling of zinc oxide nanoclusters which were biosynthesized in vivo in the Alzheimer's brain via intravenous injection of zinc gluconate solution. By using three-month-old and six-month-old Alzheimer's model mice as models, our observations demonstrate that biocompatible zinc ions could pass through the blood-brain barrier of the Alzheimer's disease mice and generate fluorescent zinc oxide nanoclusters (ZnO NCs) through biosynthesis, and then the bio-synthesized ZnO NCs could readily accumulate in situ on the hippocampus specific region for the in vivo fluorescent labeling of the affected sites. This study provides a new way for the rapid diagnosis of Alzheimer's disease and may have promising prospects in the effective diagnosis of Alzheimer's disease.

  20. Nitric oxide ameliorates zinc oxide nanoparticles-induced phytotoxicity in rice seedlings.

    PubMed

    Chen, Juan; Liu, Xiang; Wang, Chao; Yin, Shan-Shan; Li, Xiu-Ling; Hu, Wen-Jun; Simon, Martin; Shen, Zhi-Jun; Xiao, Qiang; Chu, Cheng-Cai; Peng, Xin-Xiang; Zheng, Hai-Lei

    2015-10-30

    Nitric oxide (NO) has been found to function in enhancing plant tolerance to various environmental stresses. However, role of NO in relieving zinc oxide nanoparticles (ZnO NPs)-induced phytotoxicity remains unknown. Here, sodium nitroprusside (SNP, a NO donor) was used to investigate the possible roles and the regulatory mechanisms of NO in counteracting ZnO NPs toxicity in rice seedlings. Our results showed that 10 μM SNP significantly inhibited the appearance of ZnO NP toxicity symptoms. SNP addition significantly reduced Zn accumulation, reactive oxygen species production and lipid peroxidation caused by ZnO NPs. The protective role of SNP in reducing ZnO NPs-induced oxidative damage is closely related to NO-mediated antioxidant system. A decrease in superoxide dismutase activity, as well as an increase in reduced glutathione content and peroxidase, catalase and ascorbate peroxidase activity was observed under SNP and ZnO NPs combined treatments, compared to ZnO NPs treatment alone. The relative transcript abundance of corresponding antioxidant genes exhibited a similar change. The role of NO in enhancing ZnO NPs tolerance was further confirmed by genetic analysis using a NO excess mutant (noe1) and an OsNOA1-silenced plant (noa1) of rice. Together, this study provides the first evidence indicating that NO functions in ameliorating ZnO NPs-induced phytotoxicity.

  1. Migration of point defects and a defect pair in zinc oxide using the dimer method

    SciTech Connect

    Chen, Dong; Gao, Fei; Dong, Mingdong; Liu, Bo

    2012-09-24

    The migration mechanism and the minimum energy path of vacancies, interstitials and an interstitial-vacancy pair in zinc oxide have been studied by the dimer method. The in-plane and out-of-plane migrations of zinc and oxygen vacancies are found to be anisotropic. The kick-out mechanism is energetically preferred to zinc and oxygen interstitials that can easily migrate through the ZnO crystal lattice. In addition, the migration process of an interstitial-vacancy pair as a complex of an octahedral oxygen interstitial and a zinc vacancy is dominated by an oxygen interstitial/zinc vacancy successive migration. The energy barriers indicate that the existence of oxygen interstitial in the defect pair can promote the mobility of zinc vacancy, whereas the migration of oxygen interstitial is slowed down due to the presence of zinc vacancy. In the end, we show a possible migration path of the interstitial-vacancy pair that can be dissociated through a set of displacement movements.

  2. Zinc regulates iNOS-derived nitric oxide formation in endothelial cells.

    PubMed

    Cortese-Krott, Miriam M; Kulakov, Larissa; Opländer, Christian; Kolb-Bachofen, Victoria; Kröncke, Klaus-D; Suschek, Christoph V

    2014-01-01

    Aberrant production of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathogenesis of endothelial dysfunction and vascular disease. Mechanisms responsible for the fine-tuning of iNOS activity in inflammation are still not fully understood. Zinc is an important structural element of NOS enzymes and is known to inhibit its catalytical activity. In this study we aimed to investigate the effects of zinc on iNOS activity and expression in endothelial cells. We found that zinc down-regulated the expression of iNOS (mRNA+protein) and decreased cytokine-mediated activation of the iNOS promoter. Zinc-mediated regulation of iNOS expression was due to inhibition of NF-κB transactivation activity, as determined by a decrease in both NF-κB-driven luciferase reporter activity and expression of NF-κB target genes, including cyclooxygenase 2 and IL-1β. However, zinc did not affect NF-κB translocation into the nucleus, as assessed by Western blot analysis of nuclear and cytoplasmic fractions. Taken together our results demonstrate that zinc limits iNOS-derived high output NO production in endothelial cells by inhibiting NF-κB-dependent iNOS expression, pointing to a role of zinc as a regulator of iNOS activity in inflammation.

  3. Heat-sterilized silver oxide-zinc cells: Cycle life studies

    NASA Technical Reports Server (NTRS)

    Arms, J. T.

    1973-01-01

    A JPL study was conducted to evaluate the cell design parameters that contribute to the cycle life of sealed, heat-sterilized silver oxide-zinc cells. Test cells having a rated capacity of 4.2 A-h were fabricated using zinc oxide electrodes prepared by the sintered Teflon process. Two separator variations were evaluated, one having acrylic acid and the other methacrylic acid grafted to irradiated polyethylene film. Significant results of this study include the following: (1) cycle life in excess of 300 cycles was attained; (2) a zinc oxide/silver stoichiometric ratio of 1.5 resulted in greater cycle life than a ratio of 1.1, and similar cycle life to cells having a ratio of 2; (3) cells having methacrylic acid grafted separators suffered somewhat less in capacity loss due to zinc electrode shape change than cells having acrylic acid type; (4) use of acrylic acid grafted separators was slightly superior to the methacrylic acid type in respect to silver penetration; and (5) the inclusion of a layer of potassium titanate paper adjacent to the zinc electrodes resulted in cells that achieved higher cycle life before any of the group failed than that reached by cells of any other construction.

  4. Zinc supplementation attenuates metallothionein and oxidative stress changes in kidney of streptozotocin-induced diabetic rats.

    PubMed

    Özcelik, Dervis; Nazıroglu, Mustafa; Tunçdemir, Matem; Çelik, Ömer; Öztürk, Melek; Flores-Arce, M F

    2012-12-01

    Zinc is an element that under physiological conditions preferentially binds to and is a potent inducer of metallothionein under physiological conditions. The present study was conducted to explore whether zinc supplementation morphologically and biochemically protects against diabetic nephropathy through modulation of kidney metallothionein induction and oxidative stress in streptozotocin-induced diabetic rats. Thirty-two Wistar albino male rats were equally divided into four groups. The first group was used as untreated controls and the second group was supplemented with 30 mg/kg/day zinc as zinc sulfate. The third group was treated with streptozotocin to induce diabetes and the fourth group was treated with streptozotocin and supplemented with zinc as described for group 2. The blood glucose and micro-albuminuria levels, body and kidney weights were measured during the 42-day experimental period. At the end of the experiment, the kidneys were removed from all animals from the four groups. Diabetes resulted in degenerative kidney morphological changes. The metallothionein immunoreactivity level was lower and the kidney lipid peroxidation levels were higher in the diabetes group than in the controls. The metallothionein immunoreactivity levels were higher in the tubules of the zinc-supplemented diabetic rats as compared to the non-supplemented diabetic group. The zinc and metallothionein concentrations in kidney tissue were higher in the supplemented diabetic group compared to the non-supplemented diabetes group. The activity of glutathione peroxidase did not change in any of the four groups. In conclusion, the present study shows that zinc has a protective effect against diabetic damage of kidney tissue through stimulation of metallothionein synthesis and regulation of the oxidative stress.

  5. Zinc stable isotope fractionation upon accelerated oxidative weathering of sulfidic mine waste.

    PubMed

    Matthies, R; Krahé, L; Blowes, D W

    2014-07-15

    Accelerated oxidative weathering in a reaction cell (ASTM D 5744 standard protocol) was performed over a 33 week period on well characterized, sulfidic mine waste from the Kidd Creek Cu-Zn volcanogenic massive sulfide deposit, Canada. The cell leachate was monitored for physicochemical parameters, ion concentrations and stable isotope ratios of zinc. Filtered zinc concentrations (<0.45 μm) in the leachate ranged between 4.5 mg L(-1) and 1.9 g L(-1)-potentially controlled by pH, mineral solubility kinetics and (de)sorption processes. The zinc stable isotope ratios varied mass-dependently within +0.1 and +0.52‰ relative to IRMM 3702, and were strongly dependent on the pH (rpH-d66Zn=0.65, p<0.005, n=31). At a pH below 5, zinc mobilization was governed by sphalerite oxidation and hydroxide dissolution-pointing to the isotope signature of sphalerite (+0.1 to +0.16‰). Desorption processes resulted in enrichment of (66)Zn in the leachate reaching a maximum offset of +0.32‰ compared to the proposed sphalerite isotope signature. Over a period characterized by pH=6.1 ± 0.6, isotope ratios were significantly more enriched in (66)Zn with an offset of ≈ 0.23‰ compared to sphalerite, suggesting that zinc release may have been derived from a second zinc source, such as carbonate minerals, which compose 8 wt.% of the tailings. This preliminary study confirms the benefit of applying zinc isotopes alongside standard monitoring parameters to track principal zinc sources and weathering processes in complex multi-phase matrices.

  6. The influence of target erosion grade in the optoelectronic properties of AZO coatings growth by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Zubizarreta, C.; G-Berasategui, E.; Ciarsolo, I.; Barriga, J.; Gaspar, D.; Martins, R.; Fortunato, E.

    2016-09-01

    Aluminum-doped zinc oxide (AZO) transparent conductor coating has emerged as promising substitute to tin-doped indium oxide (ITO) as electrode in optoelectronic applications such as photovoltaics or light emitting diodes (LEDs). Besides its high transmission in the visible spectral region and low resistivity, AZO presents a main advantage over other candidates such as graphene, carbon nanotubes or silver nanowires; it can be deposited using the technology industrially implemented to manufacture ITO layers, the magnetron sputtering (MS). This is a productive, reliable and green manufacturing technique. But to guarantee the robustness, reproducibility and reliability of the process there are still some issues to be addressed, such as the effect and control of the target state. In this paper a thorough study of the influence of the target erosion grade in developed coatings has been performed. AZO films have been deposited from a ceramic target by RF MS. Structure, optical transmittance and electrical properties of the produced coatings have been analyzed as function of the target erosion grade. No noticeable differences have been found neither in optoelectronic properties nor in the structure of the coatings, indicating that the RF MS is a stable and consistent process through the whole life of the target.

  7. Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics

    SciTech Connect

    Demyanets, L. N. Li, L. E.; Lavrikov, A. S.; Nikitin, S. V.

    2010-01-15

    Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

  8. Growth of zinc oxide by chemical vapor transport

    NASA Astrophysics Data System (ADS)

    Mikami, Makoto; Eto, Toshiaki; Wang, JiFeng; Masa, Yoshihiko; Isshiki, Minoru

    2005-04-01

    ZnO crystal growth by chemical vapor transport (CVT) is carried out using carbon as a transport agent. Under the optimum ΔT and growth temperature, a single crystal was grown. The carbon contamination is not detected by SIMS measurements and all the crystals are orange-red colored. It is claimed that the orange-red color is attributed to the shift of stoichiometry to zinc rich atmosphere.

  9. Atomic layer deposition of tin oxide and zinc tin oxide using tetraethyltin and ozone

    SciTech Connect

    Warner, Ellis J.; Gladfelter, Wayne L.; Johnson, Forrest; Campbell, Stephen A.

    2015-03-15

    Silicon or glass substrates exposed to sequential pulses of tetraethyltin (TET) and ozone (O{sub 3}) were coated with thin films of SnO{sub 2}. Self-limiting deposition was found using 8 s pulse times, and a uniform thickness per cycle (TPC) of 0.2 nm/cycle was observed in a small, yet reproducible, temperature window from 290 to 320 °C. The as-deposited, stoichiometric SnO{sub 2} films were amorphous and transparent above 400 nm. Interspersing pulses of diethylzinc and O{sub 3} among the TET:O{sub 3} pulses resulted in deposition of zinc tin oxide films, where the fraction of tin, defined as [at. % Sn/(at. % Sn + at. % Zn)], was controlled by the ratio of TET pulses, specifically n{sub TET}:(n{sub TET} + n{sub DEZ}) where n{sub TET} and n{sub DEZ} are the number of precursor/O{sub 3} subcycles within each atomic layer deposition (ALD) supercycle. Based on film thickness and composition measurements, the TET pulse time required to reach saturation in the TPC of SnO{sub 2} on ZnO surfaces was increased to >30 s. Under these conditions, film stoichiometry as a function of the TET pulse ratio was consistent with the model devised by Elliott and Nilsen. The as-deposited zinc tin oxide (ZTO) films were amorphous and remained so even after annealing at 450 °C in air for 1 h. The optical bandgap of the transparent ZTO films increased as the tin concentration increased. Hall measurements established that the n-type ZTO carrier concentration was 3 × 10{sup 17} and 4 × 10{sup 18} cm{sup −3} for fractional tin concentrations of 0.28 and 0.63, respectively. The carrier mobility decreased as the concentration of tin increased. A broken gap pn junction was fabricated using ALD-deposited ZTO and a sputtered layer of cuprous oxide. The junction demonstrated ohmic behavior and low resistance consistent with similar junctions prepared using sputter-deposited ZTO.

  10. Cobalt-phosphate-assisted photoelectrochemical water oxidation by arrays of molybdenum-doped zinc oxide nanorods.

    PubMed

    Lin, Yan-Gu; Hsu, Yu-Kuei; Chen, Ying-Chu; Lee, Bing-Wei; Hwang, Jih-Shang; Chen, Li-Chyong; Chen, Kuei-Hsien

    2014-09-01

    We report the first demonstration of cobalt phosphate (Co-Pi)-assisted molybdenum-doped zinc oxide nanorods (Zn(1-x)Mo(x)O NRs) as visible-light-sensitive photofunctional electrodes to fundamentally improve the performance of ZnO NRs for photoelectrochemical (PEC) water splitting. A maximum photoconversion efficiency as high as 1.05% was achieved, at a photocurrent density of 1.4 mA cm(-2). More importantly, in addition to achieve the maximum incident photon to current conversion efficiency (IPCE) value of 86%, it could be noted that the IPCE of Zn(1-x)Mo(x)O photoanodes under monochromatic illumination (450 nm) is up to 12%. Our PEC performances are comparable to those of many oxide-based photoanodes in recent reports. The improvement in photoactivity of PEC water splitting may be attributed to the enhanced visible-light absorption, increased charge-carrier densities, and improved interfacial charge-transfer kinetics due to the combined effect of molybdenum incorporation and Co-Pi modification, contributing to photocatalysis. The new design of constructing highly photoactive Co-Pi-assisted Zn(1-x)Mo(x)O photoanodes enriches knowledge on doping and advances the development of high-efficiency photoelectrodes in the solar-hydrogen field.

  11. The cytotoxic effects of titanium oxide and zinc oxide nanoparticles oh Human Cervical Adenocarcinoma cell membranes

    NASA Astrophysics Data System (ADS)

    Mironava, Tatsiana; Applebaum, Ariella; Applebaum, Eliana; Guterman, Shoshana; Applebaum, Kayla; Grossman, Daniel; Gordon, Chris; Brink, Peter; Wang, H. Z.; Rafailovich, Miriam

    2013-03-01

    The importance of titanium dioxide (TiO2) and zinc oxide (ZnO), inorganic metal oxides nanoparticles (NPs) stems from their ubiquitous applications in personal care products, solar cells and food whitening agents. Hence, these NPs come in direct contact with the skin, digestive tracts and are absorbed into human tissues. Currently, TiO2 and ZnO are considered safe commercial ingredients by the material safety data sheets with no reported evidence of carcinogenicity or ecotoxicity, and do not classify either NP as a toxic substance. This study examined the direct effects of TiO2 and ZnO on HeLa cells, a human cervical adenocarcinonma cell line, and their membrane mechanics. The whole cell patch-clamp technique was used in addition to immunohistochemistry staining, TEM and atomic force microscopy (AFM). Additionally, we examined the effects of dexamethasone (DXM), a glucocorticoid steroid known to have an effect on cell membrane mechanics. Overall, TiO2 and ZnO seemed to have an adverse effect on cell membrane mechanics by effecting cell proliferation, altering cellular structure, decreasing cell-cell adhesion, activating existing ion channels, increasing membrane permeability, and possibly disrupting cell signaling.

  12. Oxidative stress and genotoxic effect of zinc oxide nanoparticles in freshwater snail Lymnaea luteola L.

    PubMed

    Ali, Daoud; Alarifi, Saud; Kumar, Sudhir; Ahamed, Maqusood; Siddiqui, Maqsood A

    2012-11-15

    Understanding the toxic effects of nanoparticles on aquatic organism is the biggest obstacle to the safe development of nanotechnology. However, little is known about the toxic mechanisms of zinc oxide nanoparticles (ZnONPs) in freshwater snail Lymnaea luteola (L. luteola). This study was designed to investigate the possible mechanisms of genotoxicity induced by ZnONPs in freshwater snail L. luteola. ZnONPs (32 μg/ml) elicited a significant (p<0.01) reduction in glutathione (42.10% and 61.40%), glutathione-S-transferase (25.60% and 40.24%) and glutathione peroxidase (21.73% and 39.13%) with a concomitant increase in malondialdehyde level (54.50% and 57.14%; p<0.01) and catalase (34.88% and 52.56%; p<0.01) in digestive gland of L. luteola after 24 and 96 h exposure, respectively. However, a statistically significant (p<0.01) induction in DNA damage was observed by the comet assay in digestive gland cells treated with ZnONPs for 24 and 96 h. Thus, the results demonstrate that ZnONPs induce genotoxicity in digestive gland cells through oxidative stress. Freshwater snail L. luteola may be used as suitable test model for nanoecotoxicological studies in future.

  13. Formulation of nano-zinc oxide into biocomposite beads for dye decolorization

    NASA Astrophysics Data System (ADS)

    Elkady, M. F.; Hassan, H. Shokry; El-Shazly, A. H.

    2015-03-01

    Zinc oxide nano-powder was prepared using sol-gel technique to be encapsulated onto polymeric blend composed from alginate and polyvinyl alcohol to fabricate novel bio-composite beads of nano-zinc oxide. The XRD patterns of both zinc oxide nano-powder and its polymeric hybrid were crystalline in their nature. The FTIR analysis of the fabricated ZnO polymeric hybrid confirms the binding between zinc oxide and the polymeric matrix. The BET analysis demonstrated that the calculated specific surface area of the formulated ZnO beads that equal to 22.8 m2/g is comparatively less than that of the free ZnO nano-powdered that equivalent to 64.9 m2/g. The thermal stability of ZnO nano-powdered dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500rpm. Moreover, this hybrid beads are chemically stable at the acidic media. The formulated ZnO hybrid beads verified to be good adsorbent material for C.I basic blue 41 (CB41).

  14. Ternary and coupled binary zinc tin oxide nanopowders: Synthesis, characterization, and potential application in photocatalytic processes

    SciTech Connect

    Ivetić, T.B.; Finčur, N.L.; Đačanin, Lj. R.; Abramović, B.F.; Lukić-Petrović, S.R.

    2015-02-15

    Highlights: • Mechanochemically synthesized nanocrystalline zinc tin oxide (ZTO) powders. • Photocatalytic degradation of alprazolam in the presence of ZTO water suspensions. • Coupled binary ZTO exhibits enhanced photocatalytic activity compared to ternary ZTO. - Abstract: In this paper, ternary and coupled binary zinc tin oxide nanocrystalline powders were prepared via simple solid-state mechanochemical method. X-ray diffraction, scanning electron microscopy, Raman and reflectance spectroscopy were used to study the structure and optical properties of the obtained powder samples. The thermal behavior of zinc tin oxide system was examined through simultaneous thermogravimetric-differential scanning calorimetric analysis. The efficiencies of ternary (Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3}) and coupled binary (ZnO/SnO{sub 2}) zinc tin oxide water suspensions in the photocatalytic degradation of alprazolam, short-acting anxiolytic of the benzodiazepine class of psychoactive drugs, under UV irradiation were determined and compared with the efficiency of pure ZnO and SnO{sub 2}.

  15. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    EPA Science Inventory

    Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

  16. The thermovoltaic effect in zinc oxide inhomogeneously doped with mixed-valence impurities

    NASA Astrophysics Data System (ADS)

    Pronin, I. A.; Averin, I. A.; Bozhinov, A. S.; Georgieva, A. Ts.; Dimitrov, D. Ts.; Karmanov, A. A.; Moshnikov, V. A.; Papazova, K. I.; Terukov, E. I.; Yakushova, N. D.

    2015-10-01

    The thermovoltaic effect has been for the first time observed in zinc oxide. The samples had the form of ZnO/ZnO-Me sandwich structures (Me = Cu, Fe) formed by the sol-gel method. An electromotive force of 1-10 mV appeared in the temperature range of 200-300°C.

  17. Vapor-phase growth of transparent zinc oxide ceramics with c -axis orientation

    SciTech Connect

    Noritake, F.; Yamamoto, N.; Horiguchi, Y. ); Fujitsu, S.; Koumoto, K. ); Yanagida, H. )

    1991-01-01

    Large transparent specimens of polycrystalline zinc oxide with c-axis orientation have been prepared by the vapor transport method. Optical transmittance is 80% to 90% at 800 nm. X-ray diffraction peaks from faces other than (001) are negligible.

  18. Hybrid p-type copper sulphide coated zinc oxide nanowire heterojunction device

    NASA Astrophysics Data System (ADS)

    Bu, Ian Y. Y.

    2014-11-01

    A novel heterojunction was formed between zinc oxide nanowires and copper sulphide. The proposed device was fabricated by a fully solution-based process that consists of hydrothermal growth method and chemical bath deposition. The optoelectronic properties of the proposed heterojunction were evaluated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, UV-vis spectroscopy, photoluminescence measurements and current voltage characteristics.

  19. Effect of various zinc oxide materials as root-end fillings on healing after replantation.

    PubMed

    Pitt Ford, T R; Andreasen, J O; Dorn, S O; Kariyawasam, S P

    1995-11-01

    This study examined the effect of various zinc oxide materials as root-end fillings of teeth in a replantation model. A total of 35 molar teeth were used from 19 monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared and fillings placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Twelve roots were filled with IRM plus dentine chips, and six with Cavit; the tissue response around root ends filled with these materials as assessed by inflammation was similar to that previous reported to IRM and Super EBA cement and was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed around root ends filled with plain zinc oxide-eugenol or Kalzinol; however, the reaction was neither as severe nor as extensive as that to amalgam root-end fillings. Giant cells were observed most often on the surface of fillings with Cavit and zinc oxide-eugenol. It is concluded that the tissue response to IRM with or without added dentine, Super EBA and Cavit was similar and mild; it was less severe than that to zinc oxide-eugenol and Kalzinol. All these materials had a much more favourable response than amalgam

  20. 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.

  1. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    PubMed

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications. PMID:26726580

  2. Ultraflexible polymer solar cells using amorphous zinc-indium-tin oxide transparent electrodes.

    PubMed

    Zhou, Nanjia; Buchholz, Donald B; Zhu, Guang; Yu, Xinge; Lin, Hui; Facchetti, Antonio; Marks, Tobin J; Chang, Robert P H

    2014-02-01

    Polymer solar cells are fabricated on highly conductive, transparent amorphous zinc indium tin oxide (a-ZITO) electrodes. For two representative active layer donor polymers, P3HT and PTB7, the power conversion efficiencies (PCEs) are comparable to reference devices using polycrystalline indium tin oxide (ITO) electrodes. Benefitting from the amorphous character of a-ZITO, the new devices are highly flexible and can be repeatedly bent to a radius of 5 mm without significant PCE reduction. PMID:24123578

  3. A study of mercuric oxide and zinc-air battery life in hearing aids.

    PubMed

    Sparkes, C; Lacey, N K

    1997-09-01

    The requirement to phase out mercuric oxide (mercury) batteries on environmental grounds has led to the widespread introduction of zinc-air technology. The possibility arises that high drain hearing aids may not be adequately catered for by zinc-air cells, leading to poor performance. This study investigated the hearing aid user's ability to perceive differences between zinc-air and mercury cells in normal everyday usage. The data was collected for 100 experienced hearing aid users in field trials. Users report 50 per cent greater life for zinc-air cells in high power aids and 28 per cent in low power aids. The average life of the zinc-air cells range from 15 days in high power to 34 days in low power aids. Users are able to perceive a difference in sound quality in favour of zinc-air cells for low and medium power aids. The hearing aid population is not disadvantaged by phasing out mercury cells. PMID:9373545

  4. 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.

  5. Radiation Stability of Zinc Oxide Pigment Modified by Zirconium Oxide and Aluminum Oxide Nanopowders

    SciTech Connect

    Mikhailov, M. M.; Neshchimenko, V. V.; Li Chundong

    2009-01-05

    The effect on the reflective spectra of heat treatment and modification of ZnO pigments by 1-30 wt.%ZrO{sub 2} and Al{sub 2}O{sub 3} nanoparticles has been investigated before and after irradiation by 100 keV protons with a fluence of 5x10{sup 15} cm{sup -2}. It is established that with the optimum concentration of 5 wt.% nanoparticles and the temperature of 800 deg. C a 20% increase in the radiation stability is observed for the modified ZnO pigment in comparison with the not modified pigment. The decrease of absorption in the modified pigments is determined by the decrease of the intensity of the absorption bands of the zinc vacancies (V{sub zn}{sup -}), oxygen vacancies (V{sub o}{sup +}) and donor-acceptor couples (V{sub zn}-{sup -}Zn{sub i}{sup 0})

  6. Extracellular synthesis of zinc oxide nanoparticle using seaweeds of gulf of Mannar, India

    PubMed Central

    2013-01-01

    Background The biosynthesis of metal nanoparticles by marine resources is thought to be clean, nontoxic, and environmentally acceptable “green procedures”. Marine ecosystems are very important for the overall health of both marine and terrestrial environments. The use of natural sources like Marine biological resources essential for nanotechnology. Seaweeds constitute one of the commercially important marine living renewable resources. Seaweeds such as green Caulerpa peltata, red Hypnea Valencia and brown Sargassum myriocystum were used for synthesis of Zinc oxide nanoparticles. Result The preliminary screening of physico-chemical parameters such as concentration of metals, concentration of seaweed extract, temperature, pH and reaction time revealed that one seaweed S. myriocystum were able to synthesize zinc oxide nanoparticles. It was confirmed through the, initial colour change of the reaction mixture and UV visible spectrophotometer. The extracellular biosynthesized clear zinc oxide nanoparticles size 36 nm through characterization technique such as DLS, AFM, SEM –EDX, TEM, XRD and FTIR. The biosynthesized ZnO nanoparticles are effective antibacterial agents against Gram-positive than the Gram-negative bacteria. Conclusion Based on the FTIR results, fucoidan water soluble pigments present in S. myriocystum leaf extract is responsible for reduction and stabilization of zinc oxide nanoparticles. by this approach are quite stable and no visible changes were observed even after 6 months. These soluble elements could have acted as both reduction and stabilizing agents preventing the aggregation of nanoparticles in solution, extracellular biological synthesis of zinc oxide nanoparticles of size 36 nm. PMID:24298944

  7. Synthesis and characterization of lanthanum doped zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Vinod; Sonia, Suman, Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    La doped ZnO (Zn1-xLaxO, x = 0, 3, 6 and 9) were prepared via chemical co-precipitation method using Zinc Acetate, Lanthanum Acetate and Sodium Hydroxide at 50°C. Hydrate nanoparticles were annealed in air at 300°C for 3 hours. The synthesized samples have been characterized by powder X-ray diffraction and UV-Visiblespectrophotometer. The XRD measurement revealsthat the prepared nanoparticles have different microstructure without changing a hexagonal wurtzite structure. The result shows the change in nanoparticles size with the increment of lanthanum concentration for lower concentration for x = 0 to 6 and decreases at x = 9.

  8. Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion

    SciTech Connect

    Hsu, C. Y.

    2013-12-09

    We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

  9. Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion

    NASA Astrophysics Data System (ADS)

    Hsu, C. Y.

    2013-12-01

    We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

  10. Lactic acid aided electrochemical deposition of c -axis preferred orientation of zinc oxide thin films: Structural and morphological features

    NASA Astrophysics Data System (ADS)

    Whang, Thou-Jen; Hsieh, Mu-Tao; Tsai, Jia-Ming; Lee, Shyan-Jer

    2011-09-01

    Compact and homogeneous c-axis preferred orientation of zinc oxide (ZnO) films on indium tin oxide (ITO) coated glass have been prepared electrochemically at -1.2 V vs. Ag|AgCl in a weak acidic condition from 0.06 M Zn(NO 3) 2 with 3 mM lactic acid (LA) added. LA was found having strong influence on the electrodeposition of c-axis preferred orientation of zinc oxide films. Other experimental variables such as deposition temperature, potential, and precursor concentration were also conducted in this article. Among these variables, it was found that precursor concentration of zinc nitrate influenced significantly on growth direction and crystal diameter of zinc oxide. Cyclic voltammetry was used to observe the electrochemistry of the deposition. Crystallinities of the films were examined by X-ray diffractometer. The morphologies of zinc oxide films were observed with a field emitting scanning electron microscope. Optical characteristics of zinc oxide layers were measured with UV-vis spectrophotometer. The band gap of the deposited zinc oxide thin films was evaluated from the Tauc relationship of ( αhν) 2 vs. hν, which was found to be 3.31 eV.

  11. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  12. A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature. PMID:22247656

  13. A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip.

    PubMed

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

  14. High mobility transparent thin-film transistors with amorphous zinc tin oxide channel layer

    SciTech Connect

    Chiang, H.Q.; Wager, J.F.; Hoffman, R.L.; Jeong, J.; Keszler, D.A.

    2005-01-03

    Transparent thin-film transistors (TTFTs) with an amorphous zinc tin oxide channel layer formed via rf magnetron sputter deposition are demonstrated. Field-effect mobilities of 5-15 and 20-50 cm{sup 2} V{sup -1} s{sup -1} are obtained for devices post-deposition annealed at 300 and 600 deg. C, respectively. TTFTs processed at 300 and 600 deg. C yield devices with turn-on voltage of 0-15 and -5-5 V, respectively. Under both processing conditions, a drain current on-to-off ratio greater than 10{sup 7} is obtained. Zinc tin oxide is one example of a new class of high performance TTFT channel materials involving amorphous oxides composed of heavy-metal cations with (n-1)d{sup 10} ns{sup 0} (n{>=}4) electronic configurations.

  15. Contrasting the grain boundary-affected performance of zinc and indium oxide transparent conductors.

    PubMed

    Vai, A T; Rashidi, N; Fang, Y; Kuznetsov, V L; Edwards, P P

    2016-06-01

    Zinc oxide-based transparent conductors have long been advanced for their potential as low-cost, earth-abundant replacements for the indium oxide-based materials that currently dominate in practical applications. However, this potential has yet to be realized because of the difficulties in producing zinc oxide thin films with the necessary high levels of electrical conductivity and environmental stability that are readily achieved using indium oxide. To better understand the fundamental reasons for this, polycrystalline zinc and indium oxide thin films were prepared across a range of deposition temperatures using the technique of spray pyrolysis. Electrical transport measurements of these samples both as a function of temperature and UV irradiation were correlated with film morphology to illustrate that the different grain boundary behaviour of these two materials is one of the key reasons for their divergent performance. This is a critical challenge that must be addressed before any substantial increase in the adoption of ZnO-based transparent conductors can take place. PMID:26952740

  16. Contrasting the grain boundary-affected performance of zinc and indium oxide transparent conductors

    NASA Astrophysics Data System (ADS)

    Vai, A. T.; Rashidi, N.; Fang, Y.; Kuznetsov, V. L.; Edwards, P. P.

    2016-06-01

    Zinc oxide-based transparent conductors have long been advanced for their potential as low-cost, earth-abundant replacements for the indium oxide-based materials that currently dominate in practical applications. However, this potential has yet to be realized because of the difficulties in producing zinc oxide thin films with the necessary high levels of electrical conductivity and environmental stability that are readily achieved using indium oxide. To better understand the fundamental reasons for this, polycrystalline zinc and indium oxide thin films were prepared across a range of deposition temperatures using the technique of spray pyrolysis. Electrical transport measurements of these samples both as a function of temperature and UV irradiation were correlated with film morphology to illustrate that the different grain boundary behaviour of these two materials is one of the key reasons for their divergent performance. This is a critical challenge that must be addressed before any substantial increase in the adoption of ZnO-based transparent conductors can take place.

  17. 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.

  18. Measurement of valence band structure in boron-zinc-oxide films by making use of ion beams

    SciTech Connect

    Uhm, Han S.; Kwon, Gi C.; Choi, Eun H.

    2011-12-26

    Measurement of valence band structure in the boron-zinc oxide (BZO) films was developed using the secondary electron emission due to the Auger neutralization of ions. The energy distribution profile of the electrons emitted from boron-zinc-oxide films was measured and rescaled so that Auger self-convolution arose; thus, revealing the detailed structure of the valence band and suggesting that a high concentration of boron impurity in BZO films may enhance the transition of electrons and holes through the band gap from the valence to the conduction band in zinc oxide crystals; thereby improving the conductivity of the film.

  19. Enzymatic reduction of azo and indigoid compounds.

    PubMed

    Pricelius, S; Held, C; Murkovic, M; Bozic, M; Kokol, V; Cavaco-Paulo, A; Guebitz, G M

    2007-11-01

    A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy.

  20. Enzymatic reduction of azo and indigoid compounds.

    PubMed

    Pricelius, S; Held, C; Murkovic, M; Bozic, M; Kokol, V; Cavaco-Paulo, A; Guebitz, G M

    2007-11-01

    A customer- and environment-friendly method for the decolorization azo dyes was developed. Azoreductases could be used both to bleach hair dyed with azo dyes and to reduce dyes in vat dyeing of textiles. A new reduced nicotinamide adenine dinucleotide-dependent azoreductase of Bacillus cereus, which showed high potential for reduction of these dyes, was purified using a combination of ammonium sulfate precipitation and chromatography and had a molecular mass of 21.5 kDa. The optimum pH of the azoreductase depended on the substrate and was within the range of pH 6 to 7, while the maximum temperature was reached at 40 degrees C. Oxygen was shown to be an alternative electron acceptor to azo compounds and must therefore be excluded during enzymatic dye reduction. Biotransformation of the azo dyes Flame Orange and Ruby Red was studied in more detail using UV-visible spectroscopy, high-performance liquid chromatography, and mass spectrometry (MS). Reduction of the azo bonds leads to cleavage of the dyes resulting in the cleavage product 2-amino-1,3 dimethylimidazolium and N approximately 1 approximately ,N approximately 1 approximately -dimethyl-1,4-benzenediamine for Ruby Red, while only the first was detected for Flame Orange because of MS instability of the expected 1,4-benzenediamine. The azoreductase was also found to reduce vat dyes like Indigo Carmine (C.I. Acid Blue 74). Hydrogen peroxide (H(2)O(2)) as an oxidizing agent was used to reoxidize the dye into the initial form. The reduction and oxidation mechanism of Indigo Carmine was studied using UV-visible spectroscopy. PMID:17891390

  1. Evaluation of growth and biochemical indicators of Salvinia natans exposed to zinc oxide nanoparticles and zinc accumulation in plants.

    PubMed

    Hu, Changwei; Liu, Xu; Li, Xiuling; Zhao, Yongjun

    2014-01-01

    The adverse effects of zinc oxide nanoparticles (ZnO NPs) with an average diameter of 25 nm on the aquatic plant Salvinia natans (L.) All. were determined. Growth, superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase activity, and chlorophyll content of the plants were measured after 7 days of exposure to different concentrations of ZnO NPs (1 to 50 mg L(-1)). The particle distribution in the culture medium (without plants) during the first 24 h was determined using a Nanotrac 250 particle analyzer. We also investigated the zinc accumulation in leaves and roots of the plant after 7 days of exposure. Exposure to 50 mg L(-1) ZnO NPs significantly increased SOD and CAT activities (P < 0.05) and significantly depressed photosynthetic pigments (P < 0.05). However, plant growth was not significantly affected (P > 0.05). NPs completely precipitated at the bottom of the container at 8 h except for the portions of dissolution and aggregation on the roots. ZnO NPs at a concentration of 50 mg L(-1) can adversely affect S. natans, and their stress is affected by their aggregation and dissolution.

  2. Improvement of hot-dip zinc coating by enriching the inner layers with iron oxide

    NASA Astrophysics Data System (ADS)

    Shibli, S. M. A.; Manu, R.

    2006-02-01

    The performance of hot-dip galvanic coating formed on steel not only depends on the alloy composition of the superficial layer but also significantly, on the composition of the inner alloy layers at the coating/substrate interface. Further, the presence of barrier oxide layers, if any can also improve the performance of galvanic coating. In the present work, the effect of inner iron oxide barrier layer formed prior to hot-dip galvanization was investigated. A continuous and adherent iron oxide layer was formed on steel by anodic oxidation of the steel substrate. Although the wettability of oxide surface by liquid zinc was initially poor, the increase in dipping time and the transition of the oxide layer to unstable form due to the presence of Cl - ion in the flux facilitated localized growth of Fe-Zn alloy phases. The inhibitive nature of the oxide layer was temporary, since the presence of Cl - induces micro cracks on the oxide surface thereby facilitating better zinc diffusion. The modification of the substrate structure during galvanization was found to influence the galvanizing process significantly. The present study predicts scope for application of this process for protection of rusted steel specimens too.

  3. Zinc oxide nanorods modified indium tin oxide surface for amperometric urea biosensor.

    PubMed

    Palomera, Netzahualcóyotl; Balaguera, Marcia; Arya, Sunil K; Hernández, Samuel; Tomar, Maharaj S; Ramírez-Vick, Jaime E; Singh, Surinder P

    2011-08-01

    ZnO nanorods (ZnONR) grown onto indium-tin-oxide (ITO) coated glass surface using zinc nitrate hexahydrate/hexamethylenetetramine (HMT) in aqueous phase has been utilized for urea biosensor. Urease (Urs) was immobilized onto ZnONR/ITO at physiological pH via electrostatic interactions between Urs and ZnO to fabricate Urs/ZnONR/ITO bioelectrode. ZnONR/ITO electrode has been characterized using XRD, FE-SEM techniques and Urs/ZnONR/ITO bioelectrode using electrochemistry. The XRD and FE-SEM measurements confirm the formation of ZnO nanorods in wurtzite structure. Cyclic voltammetric and amperometric measurements on the Urs/ZnONR/ITO biolectrode for urea concentrations in the range of 1-20 mM reveal 0.4 microA mM(-1) sensitivity, with a response time of 3 seconds, and a detection limit of 0.13 mM. The Michaelis-Menten constant (Km) was calculated to be 9.09 mM. Results indicate that ZnO nanorods provide suitable microenvironment for urease immobilization and can be utilized in biosensor design and other biological applications. PMID:22103068

  4. Dimensional Tailoring of Hydrothermally Grown Zinc Oxide Nanowire Arrays.

    PubMed

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

    2016-01-13

    Hydrothermally synthesized ZnO nanowire arrays are critical components in a range of nanostructured semiconductor devices. The device performance is governed by relevant nanowire morphological parameters that cannot be fully controlled during bulk hydrothermal synthesis due to its transient nature. Here, we maintain homeostatic zinc concentration, pH, and temperature by employing continuous flow synthesis and demonstrate independent tailoring of nanowire array dimensions including areal density, length, and diameter on device-relevant length scales. By applying diffusion/reaction-limited analysis, we separate the effect of local diffusive transport from the c-plane surface reaction rate and identify direct incorporation as the c-plane growth mechanism. Our analysis defines guidelines for precise and independent control of the nanowire length and diameter by operating in rate-limiting regimes. We validate its utility by using surface adsorbents that limit reaction rate to obtain spatially uniform vertical growth rates across a patterned substrate. PMID:26708095

  5. Blue and white light emission from zinc oxide nanoforests.

    PubMed

    Noor, Nafisa; Lucera, Luca; Capuano, Thomas; Manthina, Venkata; Agrios, Alexander G; Silva, Helena; Gokirmak, Ali

    2015-01-01

    Blue and white light emission is observed when high voltage stress is applied using micrometer-separated tungsten probes across a nanoforest formed of ZnO nanorods. The optical spectrum of the emitted light consistently shows three fine peaks with very high amplitude in the 465-485 nm (blue) range, corresponding to atomic transitions of zinc. Additional peaks with smaller amplitudes in the 330-650 nm range and broad spectrum white light is observed depending on the excitation conditions. The spatial and spectral distribution of the emitted light, with pink-orange regions identifying percolation paths in some cases and high intensity blue and white light with center to edge variations in others, indicate that multiple mechanisms lead to light emission. Under certain conditions, the tungsten probe tips used to make electrical contact with the ZnO structures melt during the excitation, indicating that the local temperature can exceed 3422 °C, which is the melting temperature of tungsten. The distinct and narrow peaks in the optical spectra and the abrupt increase in current at high electric fields suggest that a plasma is formed by application of the electrical bias, giving rise to light emission via atomic transitions in gaseous zinc and oxygen. The broad spectrum, white light emission is possibly due to the free electron transitions in the plasma and blackbody radiation from molten silicon. The white light may also arise from the recombination through multiple defect levels in ZnO or due to the optical excitation from solid ZnO. The electrical measurements performed at different ambient pressures result in light emission with distinguishable differences in the emission properties and I-V curves, which also indicate that the dielectric breakdown of ZnO, sublimation, and plasma formation processes are the underlying mechanisms. PMID:26885458

  6. Blue and white light emission from zinc oxide nanoforests

    PubMed Central

    Capuano, Thomas; Manthina, Venkata; Agrios, Alexander G; Silva, Helena; Gokirmak, Ali

    2015-01-01

    Summary Blue and white light emission is observed when high voltage stress is applied using micrometer-separated tungsten probes across a nanoforest formed of ZnO nanorods. The optical spectrum of the emitted light consistently shows three fine peaks with very high amplitude in the 465–485 nm (blue) range, corresponding to atomic transitions of zinc. Additional peaks with smaller amplitudes in the 330–650 nm range and broad spectrum white light is observed depending on the excitation conditions. The spatial and spectral distribution of the emitted light, with pink–orange regions identifying percolation paths in some cases and high intensity blue and white light with center to edge variations in others, indicate that multiple mechanisms lead to light emission. Under certain conditions, the tungsten probe tips used to make electrical contact with the ZnO structures melt during the excitation, indicating that the local temperature can exceed 3422 °C, which is the melting temperature of tungsten. The distinct and narrow peaks in the optical spectra and the abrupt increase in current at high electric fields suggest that a plasma is formed by application of the electrical bias, giving rise to light emission via atomic transitions in gaseous zinc and oxygen. The broad spectrum, white light emission is possibly due to the free electron transitions in the plasma and blackbody radiation from molten silicon. The white light may also arise from the recombination through multiple defect levels in ZnO or due to the optical excitation from solid ZnO. The electrical measurements performed at different ambient pressures result in light emission with distinguishable differences in the emission properties and I–V curves, which also indicate that the dielectric breakdown of ZnO, sublimation, and plasma formation processes are the underlying mechanisms. PMID:26885458

  7. Rosin (colophony) and zinc oxide in adhesive bandages. An appropriate combination for rosin-sensitive patients?

    PubMed

    Gäfvert, E; Färm, G

    1995-12-01

    Adhesives and bandages containing zinc oxide (ZnO) and rosin are often used for treatment of ulcers. The aim of this work was to study a possible inhibitory effect of ZnO on the elicitation of allergic contact reactions to rosin and to determine whether such an effect might be due to the formation of zinc resinates. Patch testing in rosin-sensitive patients was performed with mixes of ZnO and rosin. The eliciting capacities of one mix in which zinc resinates might be formed and another mix in which the formation of zinc resinates was prevented, were compared to the eliciting capacity of rosin alone. If a reduction of the allergic response was observed for the mix in which zinc resinates might form and if no reduction was observed for the mix in which formation of zinc resinates was prevented, this would support the hypothesis that the reduction in eliciting capacity was due to formation of zinc resinates. However, we could not see any difference in eliciting capacity when comparing the 2 mixes with a test preparation of rosin. Commercial adhesives (bandages) containing ZnO and rosin were patch tested in 7 rosin-sensitive patients. The concentration of abietic acid in the adhesives was determined with HPLC. Abietic acid was detected in all but one of those declared to contain rosin. The patients reacted to the adhesives in which abietic acid was detected. For rosin-sensitive persons, the addition of ZnO to rosin-containing adhesives cannot be regarded as an appropriate measure to inhibit the elicitation of allergic reactions.

  8. Paramagnetic dysprosium-doped zinc oxide thin films grown by pulsed-laser deposition

    SciTech Connect

    Lo, Fang-Yuh Ting, Yi-Chieh; Chou, Kai-Chieh; Hsieh, Tsung-Chun; Ye, Cin-Wei; Hsu, Yung-Yuan; Liu, Hsiang-Lin; Chern, Ming-Yau

    2015-06-07

    Dysprosium(Dy)-doped zinc oxide (Dy:ZnO) thin films were fabricated on c-oriented sapphire substrate by pulsed-laser deposition with doping concentration ranging from 1 to 10 at. %. X-ray diffraction (XRD), Raman-scattering, optical transmission spectroscopy, and spectroscopic ellipsometry revealed incorporation of Dy into ZnO host matrix without secondary phase. Solubility limit of Dy in ZnO under our deposition condition was between 5 and 10 at. % according to XRD and Raman-scattering characteristics. Optical transmission spectroscopy and spectroscopic ellipsometry also showed increase in both transmittance in ultraviolet regime and band gap of Dy:ZnO with increasing Dy density. Zinc vacancies and zinc interstitials were identified by photoluminescence spectroscopy as the defects accompanied with Dy incorporation. Magnetic investigations with a superconducting quantum interference device showed paramagnetism without long-range order for all Dy:ZnO thin films, and a hint of antiferromagnetic alignment of Dy impurities was observed at highest doping concentration—indicating the overall contribution of zinc vacancies and zinc interstitials to magnetic interaction was either neutral or toward antiferromagnetic. From our investigations, Dy:ZnO thin films could be useful for spin alignment and magneto-optical applications.

  9. Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes

    PubMed Central

    Petrochenko, Peter E.; Skoog, Shelby A.; Zhang, Qin; Comstock, David J.; Elam, Jeffrey W.; Goering, Peter L.; Narayan, Roger J.

    2013-01-01

    Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ≈65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20–200 nm) did not influence cell viability. PMID:23881040

  10. Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes.

    PubMed

    Petrochenko, Peter E; Skoog, Shelby A; Zhang, Qin; Comstock, David J; Elam, Jeffrey W; Goering, Peter L; Narayan, Roger J

    2013-01-01

    Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ≈65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20-200 nm) did not influence cell viability.

  11. Cytotoxicity of cultured macrophages exposed to antimicrobial zinc oxide (ZnO) coatings on nanoporous aluminum oxide membranes.

    PubMed

    Petrochenko, Peter E; Skoog, Shelby A; Zhang, Qin; Comstock, David J; Elam, Jeffrey W; Goering, Peter L; Narayan, Roger J

    2013-01-01

    Zinc oxide (ZnO) is a widely used commercial material that is finding use in wound healing applications due to its antimicrobial properties. Our study demonstrates a novel approach for coating ZnO with precise thickness control onto 20 nm and 100 nm pore diameter anodized aluminum oxide using atomic layer deposition (ALD). ZnO was deposited throughout the nanoporous structure of the anodized aluminum oxide membranes. An 8 nm-thick coating of ZnO, previously noted to have antimicrobial properties, was cytotoxic to cultured macrophages. After 48 h, ZnO-coated 20 nm and 100 nm pore anodized aluminum oxide significantly decreased cell viability by ≈65% and 54%, respectively, compared with cells grown on uncoated anodized aluminum oxide membranes and cells grown on tissue culture plates. Pore diameter (20-200 nm) did not influence cell viability. PMID:23881040

  12. [Predicting biodegradability from the electrochemical characteristic of azo dyes].

    PubMed

    Guo, Jian-bo; Zhou, Ji-ti; Wang, Dong; Tian, Cun-ping; Ge, Jun; Wang, Ping; Yu, Hui

    2006-10-01

    Experiments were conducted to study some electrochemical factors affecting the bacterial reduction (cleavage) of four azo dyes. And a common mixed culture was used as test organism and the reduction of azo dyes Acid Yellow 4, 11, 17 and Acid Yellow Bis was studied. It was found that the azo dyes were reduced at different rates,which could be correlated with the reduction potential of the azo compounds in cyclic voltammetric experiments. Acid Yellow Bis (Er = -616.75 mV) was reduced at the highest rate of 0.01209 mol x (L x h)(-1), Acid Yellow 11 (Er = -593.25 mV) at 0.01040 mol x (L x h)(-1) and Acid Yellow 4 (Er = - 513 mV) at 0.007575 mol x (L x h)(-1). It is showed that the reduction potential is a preliminary tool to predict the decolorization capacity of oxidative and reductive biocatalysts.

  13. The histopathology of rat lung following exposure to zinc oxide/hexachloroethane smoke or installation with zinc chloride followed by treatment with 70% oxygen.

    PubMed Central

    Brown, R F; Marrs, T C; Rice, P; Masek, L C

    1990-01-01

    The effects of inhaled zinc oxide/hexachloroethane smoke (11,580 mg x min/m3) and intratracheally instilled zinc chloride (2.5 mg/kg body weight) have been studied in rat lung. The effects of subsequent treatment with 70% oxygen have been studied after both procedures. Both the inhalation of the smoke and instillation of zinc chloride produced similar effects that included pulmonary edema, alveolitis and, at a later stage, some fibrosis. After zinc chloride instillation, the pathological changes largely spared the periphery of the lung, while following smoke inhalation they were more diffuse. Subsequent oxygen administration had little effect on the development or progression of the pathological changes. Images FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. PMID:2384070

  14. Electrochemistry of the Zinc-Silver Oxide System. Part 2: Practical Measurements of Energy Conversion Using Commercial Miniature Cells.

    ERIC Educational Resources Information Center

    Smith, Michael J.; Vincent, Colin A.

    1989-01-01

    Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)

  15. Treatment of cutaneous candidosis in guinea pigs: effect of zinc oxide on the antifungal efficacy of nystatin.

    PubMed

    Auger, P; Colin, P; Joly, J; Poirier, S; Colin, D

    1989-09-01

    This article describes the in vivo evaluation of a new topical preparation (Zincostatin) indicated for Candida albicans infected diaper rash. In order to study the influence of the 20% zinc oxide (W/W) (a protectant) on the anti-candidal efficacy of the 100,000 U/g of nystatin found in the ointment, groups of guinea pigs received different treatments with or without local occlusion. Zinc oxide, nystatin, or the combination of both were applied, in the ointment base, on the backs of the animals inoculated with a fresh strain of Candida albicans. Macroscopic and microbiological evaluation of the skin lesions were assessed at regular intervals during 21 days. While the two treatments containing nystatin were more effective than zinc oxide alone, the latter agent did not decrease the efficacy of the antifungal drug in combination therapy. Also, zinc oxide seemed to afford some protection against local maceration induced by occlusion, which increased the severity of the infection.

  16. Hydrothermal synthesis and photocatalytic activity of zinc oxide hollow spheres.

    PubMed

    Yu, Jiaguo; Yu, Xiaoxiao

    2008-07-01

    ZnO hollow spheres with porous crystalline shells were one-pot fabricated by hydrothermal treatment of glucose/ZnCl2 mixtures at 180 degrees C for 24 h, and then calcined at different temperatures for 4 h. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. The photocatalytic activity of the as-prepared samples was evaluated by photocatalytic decolorization of Rhodamine B aqueous solution at ambient temperature. The results indicated that the average crystallite size, shell thickness, specific surface areas, pore structures, and photocatalytic activity of ZnO hollow spheres could be controlled by varying the molar ratio of glucose to zinc ions (R). With increasing R, the photocatalytic activity increases and reaches a maximum value at R = 15, which can be attributed to the combined effects of several factors such as specific surface area, the porous structure and the crystallite size. Further results show that hollow spheres can be more readily separated from the slurry system by filtration or sedimentation after photocatalytic reaction and reused than conventional powder photocatalyst. After many recycles for the photodegradation of RhB, the catalyst does not exhibit any great loss in activity, confirming ZnO hollow spheres is stability and not photocorroded. The prepared ZnO hollow spheres are also of great interest in solar cell, catalysis, separation technology, biomedical engineering, and nanotechnology.

  17. Ferromagnetism in carbon-doped zinc oxide systems.

    PubMed

    Nagare, B J; Chacko, Sajeev; Kanhere, D G

    2010-02-25

    We report spin-polarized density functional calculations of ferromagnetic properties for a series of ZnO clusters and ZnO solid containing one or two substitutional carbon impurities. We analyze the eigenvalue spectra, spin densities, molecular orbitals, and induced magnetic moments for ZnC, Zn(2)C, Zn(2)OC, carbon-substituted Zn(n)O(n) (n = 3-10, 12) clusters and the bulk ZnO. The results show that the doping induces magnetic moment of approximately 2 mu(B) in all the cases. All systems with two carbon impurities show ferromagnetic interaction, except when carbon atoms share the same zinc atom as the nearest neighbor. This ferromagnetic interaction is predominantly mediated via pi-bonds in the ring structures and through pi- and sigma-bonds in the three-dimensional structure. The calculations also show that the interaction is significantly enhanced in the solid, bringing out the role of dimensionality of the Zn-O network connecting two carbon atoms.

  18. Tailoring ferromagnetism in chromium-doped zinc oxide

    NASA Astrophysics Data System (ADS)

    Haq, Bakhtiar Ul; Ahmed, Rashid; Goumri-Said, Souraya

    2014-03-01

    The simultaneous manipulation of both charge and spin has made diluted magnetic semiconductors (DMS) a potential material for the fabrication of spintronic devices. We report DMSs based on ZnO doped with Cr in wurtzite (WZ) and zinc-blend (ZB) geometries. The injection of Cr impurities at a concentration of 6.25% has successfully tuned ferromagnetism in ZnO. To recognize the nature of magnetic interactions, two spatial configurations are investigated, where the impurity atoms are placed at minimum and maximum separation distances. The material favors the short-range magnetic coupling and has a tendency towards Cr clustering. The injection of a Cr impurity into ZnO strongly influences the electronic properties in terms of band structure, dependent on the impurity spatial distribution. It is half metallic for both structural geometries when impurity atoms have minimum separation and is metallic when they are placed far apart. Moreover, replacing Zn with Cr does not show a significant effect on the structural geometries. Our results endorse that Cr:ZnO can be efficiently used for spin-polarized transport and other spin-dependent applications in both hexagonal and cubic phases.

  19. 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.

  20. The electronic structure of co-sputtered zinc indium tin oxide thin films

    SciTech Connect

    Carreras, Paz; Antony, Aldrin; Bertomeu, Joan; Gutmann, Sebastian; Schlaf, Rudy

    2011-10-01

    Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses {approx}50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO{sub 2} films.

  1. Effect of annealing temperature on PL spectrum and surface morphology of zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Zendehnam, A.; Mirzaee, M.; Miri, S.

    2013-04-01

    Zinc oxide (ZnO) thin films were produced by thermal oxidation of Zn layers (200 nm thickness) which were coated on Si (1 0 0) substrate by DC magnetron sputtering. In order to study the effect of annealing temperature on photoluminescence (PL) properties and the surface morphology of the ZnO samples, the annealing temperature range of 500-700 °C was employed. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) for investigation of surface morphology of the ZnO samples were carried out. The surface statistical characteristics of these ZnO thin films are then evaluated against data which outcome from AFM. SEM and AFM results indicated that the annealing temperature produces larger grains and rough surfaces at higher temperatures. The results of PL spectra represent an increase in interstitial zinc with increasing annealing temperature.

  2. Removal of Fluorides and Chlorides from Zinc Oxide Fumes by Microwave Sulfating Roasting

    NASA Astrophysics Data System (ADS)

    Li, Zhiqiang; Zhang, Libo; Chen, Guo; Peng, Jinhui; Zhou, Liexing; Yin, Shaohua; Liu, Chenhui

    2015-10-01

    Dechlorination and defluorination from zinc oxide dust by microwave sulfating roasting was investigated in this study. According to proposed reactions in the process, detailed experiments were systematically conducted to study the effect of roasting temperature, holding time, air and steam flow rates on the efficiency of the removal of F and Cl. The results show that 92.3% of F and 90.5% of Cl in the fume could be purified when the condition of the roasting temperature of 650 °C, holding time at 60 min, air flow of 300 L/h and steam flow of 8 ml/min was optimized. Our investigation indicates that microwave sulfating roasting could be a promising new way for the dechlorination and defluorination from zinc oxide dust.

  3. New sources for chemical vapor transport growth of zinc oxide nanowires

    NASA Astrophysics Data System (ADS)

    Wright, Cody; Tzolov, Marian

    2015-03-01

    Zinc Oxide (ZnO) nanowires have attracted scientific interest due to their optical and piezoelectric properties. Chemical vapor transport is a simple and effective growth method. We have shown previously that the nature of the chemical reactions excludes carbon from incorporating the in the nanowires and the presence of carbon monoxide can modify the growth significantly. Building on these findings, we have developed new sources modifying the presence of carbon monoxide during the growth. We will present our findings of the source consumption and the morphology of the formed zinc oxide nanowires. These results are the base of our model for the processes within the source and in the growth zone. We are showing that the formation of thin, high aspect ratio nanowires is promoted by the presence of carbon monoxide during the growth. We will present evidence for the significance of the reactions in the gas mixture on the nanowire formation.

  4. 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.

  5. Atmospheric-pressure glow plasma synthesis of plasmonic and photoluminescent zinc oxide nanocrystals

    NASA Astrophysics Data System (ADS)

    Bilik, N.; Greenberg, B. L.; Yang, J.; Aydil, E. S.; Kortshagen, U. R.

    2016-06-01

    In this paper, we present a large-volume (non-micro) atmospheric pressure glow plasma capable of rapid, large-scale zinc oxide nanocrystal synthesis and deposition (up to 400 μg/min), whereas in the majority of the literature, nanoparticles are synthesized using micro-scale or filamentary plasmas. The reactor is an RF dielectric barrier discharge with a non-uniform gap spacing. This design encourages pre-ionization during the plasma breakdown, making the discharge uniform over a large volume. The produced zinc oxide nanocrystals typically have diameters ranging from 4 to 15 nm and exhibit photoluminescence at ≈550 nm and localized surface plasmon resonance at ≈1900 cm-1 due to oxygen vacancies. The particle size can be tuned to a degree by varying the gas temperature and the precursor mixing ratio.

  6. Si/ZnO nanorods/Ag/AZO structures as promising photovoltaic plasmonic cells

    SciTech Connect

    Placzek-Popko, E. Gwozdz, K.; Gumienny, Z.; Zielony, E.; Jacak, W.; Pietruszka, R.; Witkowski, B. S.; Wachnicki, Ł.; Gieraltowska, S.; Chang, Liann-Be

    2015-05-21

    The test structures for photovoltaic (PV) applications based on zinc oxide nanorods (NRs) that were grown using a low-temperature hydrothermal method on p-type silicon substrates (100) covered with Ag nanoparticles (NPs) were studied. The NPs of three different diameters, i.e., 5–10 nm, 20-30 nm, and 50–60 nm, were deposited using a sputtering method. The morphology and crystallinity of the structures were confirmed by scanning electron microscopy and Raman spectroscopy. It was found that the nanorods have a hexagonal wurtzite structure. An analysis of the Raman and photoluminescence spectra permitted the identification of the surface modes at 476 cm{sup −1} and 561 cm{sup −1}. The presence of these modes is evidence of nanorods oriented along the wurtzite c-axis. The NRs with Ag NPs were covered with a ZnO:Al (AZO) layer that was grown using the low-temperature atomic layer deposition technique. The AZO layer served as a transparent ohmic contact to the ZnO nanorods. The applicability of the AZO layer for this purpose and the influence of the Ag nanoparticles on the effectiveness of light acquisition by such prepared PV cells were checked by reflectance and transmittance measurements of the AZO/glass and AZO/NPs/glass reference structures. Based on these studies, the high-energy transmittance edge was assigned to the ZnO energy gap, although it is blueshifted with respect to the bulk ZnO energy gap because of Al doping. It was also shown that the most optimal PV performance is obtained from a structure containing Ag nanoparticles with a diameter of 20–30 nm. This result is confirmed by the current-voltage measurements performed with 1-sun illumination. The structures show a plasmonic effect within the short wavelength range: the PV response for the structure with Ag nanoparticles is twice that of the structure without the nanoparticles. However, the influence of the Ag nanoparticle diameters on the plasmonic effect is ambiguous.

  7. Biomimetic zinc oxide replica with structural color using butterfly (Ideopsis similis) wings as templates.

    PubMed

    Zhang, Wang; Zhang, Di; Fan, Tongxiang; Ding, Jian; Gu, Jiajun; Guo, Qixin; Ogawa, Hiroshi

    2006-09-01

    Nano-structured colorful zinc oxide (ZnO) replicas were produced using the wings of the Ideopsis similis butterfly as templates. The ZnO replicas we obtained exhibit iridescence, which was clearly observed under an optical microscope (OM). Field emission scanning electron microscope analysis shows that all the microstructure details are maintained faithfully in the ZnO replica. A computer model was established to simulate the diffraction spectral results, which agreed well with the OM images.

  8. Synthesis and Characterization of Nanostructured Zinc Oxide and Tin Oxide for VOC Sensor Devices

    NASA Astrophysics Data System (ADS)

    Ahn, Hosang

    with an emphasis on tin phases and microstructure. Although SnO is a p-type semiconductor and SnO2 is a n-type semiconductor, the data on sensitivity using three different gases were similar except for the direction of resistance changes during the detection of the gases. Such a combinatorial approach would enhance the selectivity of a VOC sensor by merging two different types of semiconducting materials. Geometric effects of the oxides on the gas sensing properties were investigated by constructing ZnO nanorods on ZnO thin film seed layers. A series of devices were prepared with seed layers of different thickness upon which nanorods with tuned density were grown. Quantitative analysis of the sensing mechanism shows that volumetric geometry of the nanorods such as diameter and length is a more critical factor than the thickness of the seed layer. In addition to control of the nanorod structure, the transition metal ions such as nickel, cobalt, and copper were doped into ZnO nanorods during electrodeposition. Such doping can provide the ability to operate at room temperature and to use flexible polymer substrates. Nickel was successfully doped in-situ into ZnO nanorods in aqueous solution. A doped concentration of 6% nickel revealed the most enhanced sensing property at room temperature under UV illumination. A mechanism is proposed to explain how the transition metal ions in zinc oxide play an important role in the gas sensitivity under UV illumination.

  9. Fully transparent thin film transistors based on zinc oxide channel layer and molybdenum doped indium oxide electrodes

    NASA Astrophysics Data System (ADS)

    MÄ dzik, Mateusz; Elamurugu, Elangovan; Viegas, Jaime

    2016-03-01

    In this work we report the fabrication of thin film transistors (TFT) with zinc oxide channel and molybdenum doped indium oxide (IMO) electrodes, achieved by room temperature sputtering. A set of devices was fabricated, with varying channel width and length from 5μm to 300μm. Output and transfer characteristics were then extracted to study the performance of thin film transistors, namely threshold voltage and saturation current, enabling to determine optimal fabrication process parameters. Optical transmission in the UV-VIS-IR are also reported.

  10. Stimulatory effects of zinc oxide nanoparticles on visual sensitivity and electroretinography b-waves in the bullfrog eye.

    PubMed

    Wahid, Fazli; Ul-Islam, Mazhar; Khan, Romana; Khan, Taous; Khattak, Waleed Ahmad; Hwang, Kyung-Hee; Park, Jong Seok; Chang, Su-Chan; Kim, You Young

    2013-08-01

    During the last decade, a large number of studies have focused on the development of nanomaterials for medical applications. Therefore, the present study was designed to evaluate the stimulatory effects of zinc oxide nanoparticles in the vertebrate visual system. Zinc oxide nanoparticles were synthesized and characterized through photoluminescence, ultraviolet (UV)-visible spectroscopy, field emission scanning electron microscopy and X-ray diffraction measurements. Furthermore, various electrophysiological recordings were obtained from the bullfrog eyecup preparations under various treatment conditions. Photoluminescence data showed a central peak at 386 nm while the UV-visible spectrum showed a sharp absorption band centered around 367 nm. Field emission scanning electron microscopy and X-ray diffraction measurements showed that synthesized zinc oxide nanoparticles have a polycrystalline wurtzite structure, with a round to oval shape and an average particle size of > 40 nm. Electroretinography (ERG) demonstrated that zinc oxide nanoparticles significantly increased the ERG b-wave amplitude in dark-adapted bullfrog eyecups and in the presence of background illumination. Zinc oxide nanoparticles also improved the visual sensitivity by 0.7 log unit of light intensity and shortened the duration of rhodopsin regeneration. Based on the results obtained, it was concluded that zinc oxide nanoparticles may be used to improve visual functions. The present study may add new dimensions to the biomedical applications of nanomaterials in eye research. PMID:23926809

  11. Insight into Biological Effects of Zinc Oxide Nanoflowers on Bacteria: Why Morphology Matters.

    PubMed

    Cai, Qian; Gao, Yangyang; Gao, Tianyi; Lan, Shi; Simalou, Oudjaniyobi; Zhou, Xinyue; Zhang, Yanling; Harnoode, Chokto; Gao, Ge; Dong, Alideertu

    2016-04-27

    Zinc oxides have gained exciting achievements in antimicrobial fields because of their advantageous properties, whereas their biological effects on bacteria are currently underexplored. In this study, biological effects of flower-shaped nano zinc oxides on bacteria were systematically investigated. Zinc oxide nanoflowers with controllable morphologies (viz., rod flowers, fusiform flowers, and petal flowers) were synthesized by modulating merely base type and concentration using the hydrothermal process. Their antibacterial power is in an order of petal flowers > fusiform flowers > rod flowers because of their differences in microscopic parameters such as specific surface area, pore size, and Zn-polar plane, etc. More importantly, the role of morphology in influencing biological effect on bacteria was examined, focusing on the morphology-induced effect on integrality of cell wall, permeability of cell membrane, DNA cleavage, etc. As for cytotoxicity, all petal flowers, fusiform flowers, and rod flowers show trivial cytotoxicity to the Hela cells. This work provides a guide for enhancing biological effect of the biocides on pathogenic bacteria by the morphological modulation.

  12. New CVD-based method for the growth of high-quality crystalline zinc oxide layers

    NASA Astrophysics Data System (ADS)

    Huber, Florian; Madel, Manfred; Reiser, Anton; Bauer, Sebastian; Thonke, Klaus

    2016-07-01

    High-quality zinc oxide (ZnO) layers were grown using a new chemical vapour deposition (CVD)-based low-cost growth method. The process is characterized by total simplicity, high growth rates, and cheap, less hazardous precursors. To produce elementary zinc vapour, methane (CH4) is used to reduce a ZnO powder. By re-oxidizing the zinc with pure oxygen, highly crystalline ZnO layers were grown on gallium nitride (GaN) layers and on sapphire substrates with an aluminum nitride (AlN) nucleation layer. Using simple CH4 as precursor has the big advantage of good controllability and the avoidance of highly toxic gases like nitrogen oxides. In photoluminescence (PL) measurements the samples show a strong near-band-edge emission and a sharp line width at 5 K. The good crystal quality has been confirmed in high resolution X-ray diffraction (HRXRD) measurements. This new growth method has great potential for industrial large-scale production of high-quality single crystal ZnO layers.

  13. 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.

  14. Influence of particle size of nano zinc oxide on the controlled delivery of Amoxicillin

    NASA Astrophysics Data System (ADS)

    Palanikumar, L.; Ramasamy, S.; Hariharan, G.; Balachandran, C.

    2013-10-01

    A great effort has been exerted to develop drug carriers aiming at satisfying the requirements, such as safety, greater efficiency, predictable therapeutic response, and prolonged release period. The present study aims at developing the use of zinc oxide nanoparticles as a carrier as a function of particle size for amoxicillin drug delivery system. The amoxicillin-loaded zinc oxide nanoparticles have a good antibacterial activity against infectious Gram-positive and Gram-negative bacteria. Zinc oxide nanoparticles have been prepared by wet chemical precipitation method varying the pH values. Particle size and morphology of the as-prepared ZnO powders are characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscope. Drug loading, in vitro drug release and antibacterial activity have been analyzed. Maximum zone of inhibition is observed for Staphylococcus epidermis. The results show that inhibitory efficacy of drug-loaded ZnO nanoparticles is very much dependent on its chosen concentration, drug loading, and size.

  15. The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.

    PubMed

    Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, M

    2014-12-21

    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization. PMID:25363298

  16. Weatherability and Leach Resistance of Wood Impregnated with Nano-Zinc Oxide

    NASA Astrophysics Data System (ADS)

    Clausen, Carol A.; Green, Frederick; Nami Kartal, S.

    2010-09-01

    Southern pine specimens vacuum-treated with nano-zinc oxide (nano-ZnO) dispersions were evaluated for leach resistance and UV protection. Virtually, no leaching occurred in any of the nano-ZnO-treated specimens in a laboratory leach test, even at the highest retention of 13 kg/m3. However, specimens treated with high concentrations of nano-ZnO showed 58-65% chemical depletion after 12 months of outdoor exposure. Protection from UV damage after 12 months exposure is visibly obvious on both exposed and unexposed surfaces compared to untreated controls. Graying was markedly diminished, although checking occurred in all specimens. Nano-zinc oxide treatment at a concentration of 2.5% or greater provided substantial resistance to water absorption following 12 months of outdoor exposure compared to untreated and unweathered southern pine. We conclude that nano-zinc oxide can be utilized in new wood preservative formulations to impart resistance to leaching, water absorption and UV damage of wood.

  17. The catalytic behavior of zinc oxide prepared from various precursors and by different methods

    SciTech Connect

    Perez-Lopez, Oscar W.

    2005-12-08

    Samples of zinc oxide were obtained by thermal decomposition of zinc salts (acetate and nitrate) and by precipitation (chloride and nitrate). The samples were characterized by S {sub BET}, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and scanning electron microscopy (SEM). XRD showed that ZnO crystals exhibited similar morphologies, while the crystal size and the particles morphology, availed by SEM, are dependent on the preparation method and the precursor salt utilized. The catalytic properties were evaluated to sec-butyl alcohol (SBA) reaction, using nitrogen, hydrogen and synthetic air as carrier gas. The catalytic properties of ZnO surface are strongly dependent on crystal size, atmosphere of reaction and zinc salts precursor. The activity to dehydrogenation of SBA in oxidant atmosphere is strongly sensitive to crystal size, while the selectivity to methyl ethyl ketone (MEK) is slightly sensitive. The activity to dehydrogenation and dehydration of SBA increases with change of atmosphere reaction from oxidant to reducing. High reaction temperatures and reducing environment for ZnO sample with small crystal size decrease significantly the selectivity to MEK. The ZnO crystal size has an important role to establish the properties of partial reduction of ZnO and catalytic properties.

  18. Enhanced zinc oxide and graphene nanostructures for electronics and sensing applications

    NASA Astrophysics Data System (ADS)

    Verma, Ved Prakash

    Zinc oxide and graphene nanostructures are important technological materials because of their unique properties and potential applications in future generation of electronic and sensing devices. This dissertation investigates a brief account of the strategies to grow zinc oxide nanostructures (thin film and nanowire) and graphene, and their applications as enhanced field effect transistors, chemical sensors and transparent flexible electrodes. Nanostructured zinc oxide (ZnO) and low-gallium doped zinc oxide (GZO) thin films were synthesized by a magnetron sputtering process. Zinc oxide nanowires (ZNWs) were grown by a chemical vapor deposition method. Field effect transistors (FETs) of ZnO and GZO thin films and ZNWs were fabricated by standard photo and electron beam lithography processes. Electrical characteristics of these devices were investigated by nondestructive surface cleaning, ultraviolet irradiation treatment at high temperature and under vacuum. GZO thin film transistors showed a mobility of ˜5.7 cm2/V·s at low operation voltage of <5 V and a low turn-on voltage of ˜0.5 V with a sub threshold swing of ˜85 mV/decade. Bottom gated FET fabricated from ZNWs exhibit a very high on-to-off ratio (˜106) and mobility (˜28 cm2/V·s). A bottom gated FET showed large hysteresis of ˜5.0 to 8.0 V which was significantly reduced to ˜1.0 V by the surface treatment process. The results demonstrate charge transport in ZnO nanostructures strongly depends on its surface environmental conditions and can be explained by formation of depletion layer at the surface by various surface states. A nitric oxide (NO) gas sensor using single ZNW, functionalized with Cr nanoparticles was developed. The sensor exhibited average sensitivity of ˜46% and a minimum detection limit of ˜1.5 ppm for NO gas. The sensor also is selective towards NO gas as demonstrated by a cross sensitivity test with N2, CO and CO2 gases. Graphene film on copper foil was synthesized by chemical vapor

  19. 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.

  20. Acceptor conductivity in bulk zinc oxide (0001) crystals

    NASA Astrophysics Data System (ADS)

    Adekore, Bababunmi Tolu

    ZnO is a promising wide bandgap semiconductor. Its renowned and prominent properties as its bandgap of 3.37eV at 4.2K; its very high excitonic binding energy, 60meV; its high melting temperature, 2248K constitute the basis for the recently renewed and sustained scientific interests in the material. In addition to the foregoing, the availability of bulk substrates of industrially relevant sizes provides important opportunities such as homoepitaxial deposition of the material which is a technological asset in the production of efficient optoelectronic and electronic devices. The nemesis of wide bandgap materials cannot be more exemplified than in ZnO. The notorious limitation of asymmetric doping and the haunting plague of electrically active point defects dim the bright future of the material. In this case, the search for reliable and consistent acceptor conductivity in bulk substrates has been hitherto, unsuccessful. In the dissertation that now follows, our efforts have been concerted in the search for a reliable acceptor. We have carefully investigated the science of point defects in the material, especially those responsible for the high donor conductivity. We also investigated and herein report variety of techniques of introducing acceptors into the material. We employ the most relevant and informative characterization techniques in verifying both the intended conductivity and the response of intrinsic crystals to variation in temperature and strain. And finally we explain deviations, where they exist, from ideal acceptor characteristics. Our work on reliable acceptor has been articulated in four papers. The first establishing capacitance based methods of monitoring electrically active donor defects. The second investigates the nature of anion acceptors on the oxygen sublattice. A study similar to the preceding study was conducted for cation acceptors on the zinc sublattice and reported in the third paper. Finally, an analysis of the response of the crystal to

  1. High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition

    SciTech Connect

    Anders, Andre; Lim, Sunnie H.N.; Yu, Kin Man; Andersson, Joakim; Rosen, Johanna; McFarland, Mike; Brown, Jeff

    2009-04-24

    Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

  2. Toxicity to woodlice of zinc and lead oxides added to soil litter

    USGS Publications Warehouse

    Beyer, W.N.; Anderson, A.

    1985-01-01

    Previous studies have shown that high concentrations of metals in soil are associated with reductions in decomposer populations. We have here determined the relation between the concentrations of lead and zinc added as oxides to soil litter and the survival and reproduction of a decomposer population under controlled conditions. Laboratory populations of woodlice (Porcellio scaber Latr) were fed soil litter treated with lead or zinc at concentrations that ranged from 100 to 12,800 ppm. The survival of the adults, the maximum number of young alive, and the average number of young alive, were recorded over 64 weeks. Lead at 12,800 ppm and zinc at 1,600 ppm or more had statistically significant (p < 0.05) negative effects on the populations. These results agree with field observations suggesting that lead and zinc have reduced populations of decomposers in contaminated forest soil litter, and concentrations are similar to those reported to be associated with reductions in natural populations of decomposers. Poisoning of decomposers may disrupt nutrient cycling, reduce the numbers of invertebrates available to other wildlife for food, and contribute to the contamination of food chains.

  3. Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide

    SciTech Connect

    Choi, Seung-Ha; Jung, Woo-Shik; Park, Jin-Hong

    2012-11-19

    In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide ({alpha}-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R{sub s} measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the {alpha}-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in {alpha}-IGZO was dramatically increased, contributing to the decrease of resistivity ({rho}) from 1.96 {Omega} cm (as-deposited {alpha}-IGZO) to 1.33 Multiplication-Sign 10{sup -3}{Omega} cm (350 Degree-Sign C annealed {alpha}-IGZO).

  4. High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

    SciTech Connect

    Lee, Ching-Ting Lin, Yung-Hao; Lin, Jhong-Ham

    2015-01-28

    Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g{sub m} change, threshold voltage V{sub T} change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

  5. High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

    NASA Astrophysics Data System (ADS)

    Lee, Ching-Ting; Lin, Yung-Hao; Lin, Jhong-Ham

    2015-01-01

    Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance gm change, threshold voltage VT change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

  6. Copper and Zinc Oxide Composite Nanostructures for Solar Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Wu, Fei

    Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications. In this study, we explore oxides of copper (CuO and Cu2O) in a nanowire morphology as alternate energy harvesting materials. CuO has a bandgap of 1.2 eV whereas Cu2O has a bandgap of 2.1 eV making them ideally suited for absorbing solar radiation. First, we develop a method to synthesize vertical, single crystalline CuO and Cu2O nanowires of ~50 microm length and aspect ratios of ~200. CuO nanowire arrays are synthesized by thermal oxidation of Cu foils. Cu2O nanowire arrays are synthesized by thermal reduction of CuO nanowires. Next, surface engineering of these nanowires is achieved using atomic layer deposition (ALD) of ZnO. By depositing 1.4 nm of ZnO, a highly defective surface is produced on the CuO nanowires. These defects are capable of trapping charge as is evident through persistent photoconductivity measurements of ZnO coated CuO nanowires. The same nanowires serve as efficient photocatalysts reducing CO2 to CO with a yield of 1.98 mmol/g-cat/hr. Finally, to develop a robust platform for flexible solar cells, a protocol to transfer vertical CuO nanowires inside flexible polydimethylsiloxane (PDMS) is demonstrated. Embedded CuO nanowires-ZnO pn junctions show a VOC of 0.4 V and a JSC of 10.4 microA/cm2 under white light illumination of 5.7 mW/cm2. Thus, this research provides broad

  7. Oxidation reactivity of zinc-cysteine clusters in metallothionein.

    PubMed

    Kassim, Rima; Ramseyer, Christophe; Enescu, Mironel

    2013-03-01

    Evaluating the reactivity of the metal-thiolate clusters in metallothionein (MT) is a key step in understanding the biological functions of this protein. The effects of the metal clustering and protein environment on the thiolate reactivity with hydrogen peroxide (H(2)O(2)) were investigated by performing quantum theory calculations with chemical accuracy at two levels of complexity. At the first level, the reactivity with H(2)O(2) of a model system ([(Zn)(3)(MeS)(9)](3-), MeS is methanethiolate) of the β domain cluster of MT was evaluated using density functional theory (DFT) with the mPW1PW91 functional. At the second level of complexity, the protein environment was included in the reactant system and the calculations were performed with the hybrid ONIOM method combining the DFT-mPW1PW91 and the semiempirical PM6 levels of theory. In these conditions, the energy barrier for the oxidation of the most reactive terminal thiolate was 21.5 kcal mol(-1). This is 3 kcal mol(-1) higher than that calculated for the terminal thiolate in the model system [(Zn)(3)(MeS)(9)](3-) and about 7 kcal mol(-1) higher than that obtained for the free thiolate. In spite of this rise of the energy barrier induced by the protein environment, the thiolate oxidation by H(2)O(2) is confirmed as a possible way for metal release from MT. On the other hand, the results suggest that the antioxidant role of MT in the living cell cannot be as important as that of glutathione (which bears a free thiol). PMID:23334196

  8. Production of zinc and manganese oxide particles by pyrolysis of alkaline and Zn-C battery waste.

    PubMed

    Ebin, Burçak; Petranikova, Martina; Steenari, Britt-Marie; Ekberg, Christian

    2016-05-01

    Production of zinc and manganese oxide particles from alkaline and zinc-carbon battery black mass was studied by a pyrolysis process at 850-950°C with various residence times under 1L/minN2(g) flow rate conditions without using any additive. The particular and chemical properties of the battery waste were characterized to investigate the possible reactions and effects on the properties of the reaction products. The thermodynamics of the pyrolysis process were studied using the HSC Chemistry 5.11 software. The carbothermic reduction reaction of battery black mass takes place and makes it possible to produce fine zinc particles by a rapid condensation, after the evaporation of zinc from a pyrolysis batch. The amount of zinc that can be separated from the black mass is increased by both pyrolysis temperature and residence time. Zinc recovery of 97% was achieved at 950°C and 1h residence time using the proposed alkaline battery recycling process. The pyrolysis residue is mainly MnO powder with a low amount of zinc, iron and potassium impurities and has an average particle size of 2.9μm. The obtained zinc particles have an average particle size of about 860nm and consist of hexagonal crystals around 110nm in size. The morphology of the zinc particles changes from a hexagonal shape to s spherical morphology by elevating the pyrolysis temperature.

  9. Production of zinc and manganese oxide particles by pyrolysis of alkaline and Zn-C battery waste.

    PubMed

    Ebin, Burçak; Petranikova, Martina; Steenari, Britt-Marie; Ekberg, Christian

    2016-05-01

    Production of zinc and manganese oxide particles from alkaline and zinc-carbon battery black mass was studied by a pyrolysis process at 850-950°C with various residence times under 1L/minN2(g) flow rate conditions without using any additive. The particular and chemical properties of the battery waste were characterized to investigate the possible reactions and effects on the properties of the reaction products. The thermodynamics of the pyrolysis process were studied using the HSC Chemistry 5.11 software. The carbothermic reduction reaction of battery black mass takes place and makes it possible to produce fine zinc particles by a rapid condensation, after the evaporation of zinc from a pyrolysis batch. The amount of zinc that can be separated from the black mass is increased by both pyrolysis temperature and residence time. Zinc recovery of 97% was achieved at 950°C and 1h residence time using the proposed alkaline battery recycling process. The pyrolysis residue is mainly MnO powder with a low amount of zinc, iron and potassium impurities and has an average particle size of 2.9μm. The obtained zinc particles have an average particle size of about 860nm and consist of hexagonal crystals around 110nm in size. The morphology of the zinc particles changes from a hexagonal shape to s spherical morphology by elevating the pyrolysis temperature. PMID:26547409

  10. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis.

    PubMed

    Gutknecht, Toni; Gustafsson, Anna; Forsgren, Christer; Ekberg, Christian; Steenari, Britt-Marie

    2015-01-01

    Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production. PMID:26421313

  11. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis

    PubMed Central

    Gutknecht, Toni; Gustafsson, Anna; Forsgren, Christer; Ekberg, Christian; Steenari, Britt-Marie

    2015-01-01

    Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production. PMID:26421313

  12. Proteus mirabilis alleviates zinc toxicity by preventing oxidative stress in maize (Zea mays) plants.

    PubMed

    Islam, Faisal; Yasmeen, Tahira; Riaz, Muhammad; Arif, Muhammad Saleem; Ali, Shafaqat; Raza, Syed Hammad

    2014-12-01

    Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity.

  13. 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%)

  14. Alcohol vapor sensing by cadmium-doped zinc oxide thick films based chemical sensor

    NASA Astrophysics Data System (ADS)

    Zargar, R. A.; Arora, M.; Chackrabarti, S.; Ahmad, S.; Kumar, J.; Hafiz, A. K.

    2016-04-01

    Cadmium-doped zinc oxide nanoparticles were derived by simple chemical co-precipitation route using zinc acetate dihydrate and cadmium acetate dihydrate as precursor materials. The thick films were casted from chemical co-precipitation route prepared nanoparticles by economic facile screen printing method. The structural, morphological, optical and electrical properties of the film were characterized relevant to alcohol vapor sensing application by powder XRD, SEM, UV-VIS and DC conductivity techniques. The response and sensitivity of alcohol (ethanol) vapor sensor are obtained from the recovery curves at optimum working temperature range from 20∘C to 50∘C. The result shows that maximum sensitivity of the sensor is observed at 25∘C operating temperature. On varying alcohol vapor concentration, minor variation in resistance has been observed. The sensing mechanism of sensor has been described in terms of physical adsorption and chemical absorption of alcohol vapors on cadmium-doped zinc oxide film surface and inside film lattice network through weak hydrogen bonding, respectively.

  15. The role of crystallographic texture in achieving low friction zinc oxide nanolaminate films

    NASA Astrophysics Data System (ADS)

    Mojekwu, Nneoma

    Metal oxide nanolaminate films are potential high temperature solid lubricants due to their ability to exhibit significant plasticity when grain size is reduced to the nanometer scale, and defective growth structure is achieved by condensation of oxygen vacancies to form intrinsic stacking faults. This is in contrast to conventional microcrystalline and single crystal oxides that exhibit brittle fracture during loading in a sliding contact. This study emphasizes the additional effect of growth orientation, in particular crystallographic texture, on determining the sliding friction behavior in nanocolumnar grain zinc oxide films grown by atomic layer deposition. It was determined that zinc oxide low (0002) versus higher (101¯3) surface energy crystallographic planes influenced the sliding friction coefficient. Texturing of the (0002) grains resulted in a decreased adhesive component of friction thereby lowering the sliding friction coefficient to ˜0.25, while the friction coefficient doubled to ˜0.5 with increasing contribution of surface (101¯3) grains. In addition, the variation of the x-ray grazing incident angle from 0.5° to 5° was studied to better understand the surface grain orientation as a function of ZnO layer thickness in one versus four bilayer nanolaminates where the under layer (seed layer) was load-bearing Zn(Ti,Zr)O3.

  16. Fabrication of silver nanowires and metal oxide composite transparent electrodes and their application in UV light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Yan, Xingzhen; Ma, Jiangang; Xu, Haiyang; Wang, Chunliang; Liu, Yichun

    2016-08-01

    In this paper, we prepared the silver nanowires (AgNWs)/aluminum-doped zinc oxide (AZO) composite transparent conducting electrodes for n-ZnO/p-GaN heterojunction light emitting-diodes (LEDs) by drop casting AgNW networks and subsequent atomic layer deposition (ALD) of AZO at 150 °C. The contact resistances between AgNWs were dramatically reduced by pre-annealing in the vacuum chamber before the ALD of AZO. In this case, AZO works not only as the conformal passivation layer that protects AgNWs from oxidation, but also as the binding material that improves AgNWs adhesion to substrates. Due to the localized surface plasmons (LSPs) of the AgNWs resonant coupling with the ultraviolet (UV) light emission from the LEDs, a higher UV light extracting efficiency is achieved from LEDs with the AgNWs/AZO composite electrodes in comparison with the conventional AZO electrodes. Additionally, the antireflective nature of random AgNW networks in the composite electrodes caused a broad output light angular distribution, which could be of benefit to certain optoelectronic devices like LEDs and solar cells.

  17. Functional zinc oxide nanostructures for electronic and energy applications

    NASA Astrophysics Data System (ADS)

    Prasad, Abhishek

    vacuum levels. We found that there exists a minimum Eth as we scale the threshold field with pressure. This behavior is explained by referring to Paschen's law.(4) We have studied the application of ZnO nanostructures for solar energy harvesting. First, as-grown and (CdSe) ZnS QDs decorated ZnO NBs and ZnONWs were tested for photocurrent generation. All these nanostructures offered fast response time to solar radiation. The decoration of QDs decreases the stable current level produced by ZnONWs but increases that generated by NBs. It is possible that NBs offer more stable surfaces for the attachment of QDs. In addition, our results suggests that performance degradation of solar cells made by growing ZnO NWs on ITO is due to the increase in resistance of ITO after the high temperature growth process. Hydrogen annealing also improve the efficiency of the solar cells by decreasing the resistance of ITO. Due to the issues on ITO, we use Ni foil as the growth substrates. Performance of solar cells made by growing ZnO NWs on Ni foils degraded after Hydrogen annealing at both low (300°C) and high (600°C) temperatures since annealing passivates native defects in ZnONWs and thus reduce the absorption of visible spectra from our solar simulator. Decoration of QDs improves the efficiency of such solar cells by increasing absorption of light in the visible region. Using a better electrolyte than phosphate buffer solution (PBS) such as KI also improves the solar cell efficiency. (5) Finally, we have attempted p-type doping of ZnO NWs using various growth precursors including phosphorus pentoxide, sodium fluoride, and zinc fluoride. We have also attempted to create p-type carriers via introducing interstitial fluorine by annealing ZnO nanostructures in diluted fluorine gas. In brief, we are unable to reproduce the growth of reported p-type ZnO nanostructures. However; we have identified the window of temperature and duration of post-growth annealing of ZnO NWs in dilute fluorine gas

  18. Enhanced antibacterial activity of zinc oxide nanoparticles synthesized using Petroselinum crispum extracts

    SciTech Connect

    Stan, Manuela Popa, Adriana; Toloman, Dana; Silipas, Teofil-Danut; Vodnar, Dan Cristian; Katona, Gabriel

    2015-12-23

    The present contribution reports the synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous leaf and root extracts of Petroselinum crispum (parsley) and characterization of as-prepared samples. ZnO NPs are subjected to X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) studies. The XRD studies reveal a hexagonal wurtzite structure without supplementary diffraction lines for all ZnO samples. TEM analysis shows that the particle size is influenced by the type of plant extract. The EPR spectra indicate the presence of Mn{sup 2+} ions in ZnO sample synthesized using P. crispum leaf extract, while zinc vacancy complexes and oxygen vacancies are evidenced in all analyzed samples. ZnO NPs synthesized using P. crispum extracts exhibit increased (2-16 times) antibacterial activity as compared to chemically synthesized ZnO NPs.

  19. Fabrication and Characterization of Nanostructure Zinc Oxide for LP Gas Sensor

    NASA Astrophysics Data System (ADS)

    Yuliarto, Brian; Iqbal, Muhammad; Julia, Sri; Nugraha

    2010-10-01

    Porous thin layer of zinc oxide have been made using chemical bath deposition method with the precursor of zinc nitrate tetrahydrate on a substrate of alumina (Al2O3). The morphology of the formed layer has the form of sheet structure and flowerlike structure. ZnO layers showed the lack of oxygen. Conductivity sensors vary with changes in operating temperature, the higher the operating temperature, the higher the conductivity. The best performance is shown by the sensor with 100% solvent composition of water (sheet structure) at a temperature of 200° C with a sensitivity of 44.83%, 80 seconds response time and 90 seconds recovery time. The sensor is able to detect the presence of LPG and also can measure the concentration of LPG.

  20. Hot gas desulfurization with sorbents containing oxides of zinc, iron, vanadium and copper

    SciTech Connect

    Akyurtlu, A.; Akyurtlu, J.F.

    1992-01-01

    The main objective of this research is to evaluate the desulfurization performance of novel sorbents consisting of different combinations of zinc, iron, vanadium and copper oxides; and to develop a sorbent which can reduce H{sub 2}S levels to less than 1 ppmv, which can stabilize zinc, making operations above 650{degrees}C possible, and which can produce economically recoverable amounts of elemental sulfur during regeneration. This objective will be accomplished by evaluating the sorbent performance using fixed-bed and TGA experiments supported by sorbent characterization at various reaction extents. In the seventh quarter, the screening of the promoted sorbents in the packed bed reactor was continued. The results of this work were presented at the 1992 University Coal Research Contractors, Review Conference at Pittsburgh, PA.

  1. 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.

  2. Highly conductive indium zinc oxide prepared by reactive magnetron cosputtering technique using indium and zinc metallic targets

    SciTech Connect

    Tsai, T. K.; Chen, H. C.; Lee, J. H.; Huang, Y. Y.; Fang, J. S.

    2010-05-15

    Zn-doped In{sub 2}O{sub 3} film is frequently deposited from an oxide target; but the use of metallic target is increasingly expected as preparing the film with comparable properties. This work aimed to prepare a highly conductive and transparent Zn-doped In{sub 2}O{sub 3} thin film on Corning Eagle{sup 2000} glass substrate by magnetron cosputtering method using indium and zinc targets. Structural characterization was performed using x-ray diffraction and x-ray photoelectron spectroscopy. The film had an amorphous structure when the film was prepared on an unheated substrate, but had an In{sub 2}O{sub 3} polycrystalline structure when the film was deposited on 150 and 300 deg. C substrates. The electrical properties of the film were greatly affected by annealing; the Zn-doped In{sub 2}O{sub 3} film had a low resistivity of 6.1x10{sup -4} {Omega} cm and an average transmittance of 81.7% when the film was deposited without substrate heating and followed a 600 deg. C annealing.

  3. Nitric oxide and zinc-mediated protein assemblies involved in mu opioid receptor signaling.

    PubMed

    Rodríguez-Muñoz, María; Garzón, Javier

    2013-12-01

    Opioids are among the most effective analgesics in controlling the perception of intense pain, although their continuous use decreases their potency due to the development of tolerance. The glutamate N-methyl-D-aspartate (NMDA) receptor system is currently considered to be the most relevant functional antagonist of morphine analgesia. In the postsynapse of different brain regions the C terminus of the mu-opioid receptor (MOR) associates with NR1 subunits of NMDARs, as well as with a series of signaling proteins, such as neural nitric oxide synthase (nNOS)/nitric oxide (NO), protein kinase C (PKC), calcium and calmodulin-dependent kinase II (CaMKII) and the mitogen-activated protein kinases (MAPKs). NO is implicated in redox signaling and PKC falls under the regulation of zinc metabolism, suggesting that these signaling elements might participate in the regulation of MOR activity by the NMDAR. In this review, we discuss the influence of redox signaling in the mechanisms whose plasticity triggers opioid tolerance. Thus, the MOR C terminus assembles a series of signaling proteins around the homodimeric histidine triad nucleotide-binding protein 1 (HINT1). The NMDAR NR1 subunit and the regulator of G protein signaling RGSZ2 bind HINT1 in a zinc-independent manner, with RGSZ2 associating with nNOS and regulating MOR-induced production of NO. This NO acts on the RGSZ2 zinc finger, providing the zinc ions that are required for PKC/Raf-1 cysteine-rich domains to simultaneously bind to the histidines present in the HINT1 homodimer. The MOR-induced activation of phospholipase β (PLCβ) regulates PKC, which increases the reactive oxygen species (ROS) by acting on NOX/NADPH, consolidating the long-term PKC activation required to regulate the Raf-1/MAPK cascade and enhancing NMDAR function. Thus, RGSZ2 serves as a Redox Zinc Switch that converts NO signals into Zinc signals, thereby modulating Redox Sensor Proteins like PKCγ and Raf-1. Accordingly, redox-dependent and

  4. 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.

  5. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    SciTech Connect

    Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

    2013-04-15

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ{sub m}). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by

  6. Bio-Fabrication of zinc oxide nanoparticles using leaf extract of Parthenium hysterophorus L. and its size-dependent antifungal activity against plant fungal pathogens

    NASA Astrophysics Data System (ADS)

    Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2013-08-01

    The study reports the synthesis and characterization of zinc oxide nanoparticles from weed plant by a novel method. The aim of this work is to synthesize zinc oxide nanoparticles from Parthenium hysterophorus L. by inexpensive, ecofriendly and simple method. Highly stable, spherical and hexagonal zinc oxide nanoparticles were synthesized by using different concentrations of 50% and 25% parthenium leaf extracts. Both the concentrations of the leaf extract act as reducing and capping agent for conversion of nanoparticles. Formation of zinc oxide nanoparticles have been confirmed by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier trans-form infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis with energy dispersive X-ray analysis (EDX). SEM, TEM and EDX analysis reveals that spherical and hexagonal zinc oxide nanoparticle sizes were 27 ± 5 nm and 84 ± 2 nm respectively and chemical composition of zinc oxide were present. We synthesized different sized zinc oxide nanoparticles and explored the size-dependent antifungal activity against plant fungal pathogens. Highest zone of inhibition was observed in 25 μg/ml of 27 ± 5 nm size zinc oxide nanoparticles against Aspergillus flavus and Aspergillus niger. Parthenium mediated zinc oxide nanoparticles were synthesized and proved to be good antifungal agents and environment friendly.

  7. 40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Lithium salt of sulfophenyl azo phenyl... Significant New Uses for Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo... substance identified generically as lithium salt of sulfophenyl azo phenyl azo disulfostilbene (PMN...

  8. 40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Lithium salt of sulfophenyl azo phenyl... Significant New Uses for Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo... substance identified generically as lithium salt of sulfophenyl azo phenyl azo disulfostilbene (PMN...

  9. 40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lithium salt of sulfophenyl azo phenyl... Significant New Uses for Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo... substance identified generically as lithium salt of sulfophenyl azo phenyl azo disulfostilbene (PMN...

  10. 40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Lithium salt of sulfophenyl azo phenyl... Significant New Uses for Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo... substance identified generically as lithium salt of sulfophenyl azo phenyl azo disulfostilbene (PMN...

  11. 40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lithium salt of sulfophenyl azo phenyl... Significant New Uses for Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo... substance identified generically as lithium salt of sulfophenyl azo phenyl azo disulfostilbene (PMN...

  12. Greener syntheses of metallic nanoparticles and zinc oxide nanopowders

    NASA Astrophysics Data System (ADS)

    Samson, Jacopo

    In recent years, nanotechnology and nanomaterials synthesis have attracted a great deal of attention in the scientific community. Nanomaterials display size and morphology-related optical properties that differ from their bulk counterparts and therefore can be used for many applications in different fields such as biomedicine, electronics, antibacterial agents, and energy. Attempts to fabricate different morphologies of metallic and metal oxide nanoparticles (NPs) have successfully yielded attractive nanostructures such as particles, rods, helices, combs, tetra-pods, and flowers, all displaying properties mainly related to their enhanced surface area and/or aspect ratios. Most of the above mentioned nanomaterials productions have employed harsh synthetic routes such as high temperatures, low pressures, and the use of costly equipments. Here we show how a greener approach to nanomaterials synthesis is feasible with both minimization of aqueous precursors, energy and employment of a multi-block heater for temperature control. We present in this thesis several methods for the preparation of NPs of several materials that focus on minimizing the environmental impact of the synthesis itself. First, we describe the use of the toroidal form of plasmid DNA as a rigid narrowly dispersed bio-polymeric nanocavity, which mold the formation of disc-shaped nanoparticles of several types of metals. This approach exploits several properties of plasmid DNA: (a) DNA affinity for metal cations, (b) toroidal plasmid DNA structures which are favored by metal ionic binding, and (c) the ability to vary plasmid size. Herein, we present a complementary synthetic method based on a kinetic approach wherein the plasmid DNA acts as a template to initiate and control the formation of Au and other metallic NPs by incubation at elevated temperatures. Also reported herein is a simple, scalable hydrothermal method to make ZnO NPs that exploits temperature to precisely control the range of pH values

  13. Thin-film heterostructures based on oxides of copper and zinc obtained by RF magnetron sputtering in one vacuum cycle

    NASA Astrophysics Data System (ADS)

    Afanasjev, V.; Bazhan, M.; Klimenkov, B.; Mukhin, N.; Chigirev, D.

    2016-07-01

    Investigations of formation conditions of oxide heterostructures ZnO/CuO in the same vacuum cycle using RF magnetron sputtering of powder targets of zinc and copper oxides were carried out. The optical and electrical properties of the thin film structures were studied.

  14. Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

    SciTech Connect

    Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth; Geier, Michael L.; Prabhumirashi, Pradyumna L.; Hersam, Mark C.

    2014-02-10

    We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm{sup 2} V{sup −1} s{sup −1} at low operating voltages (<5 V) in air. We further show that the SWCNT-ZTO hybrid ambipolar FETs can be integrated into functional inverter circuits that display high peak gain (>10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures.

  15. Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

  16. Molybdenum as a contact material in zinc tin oxide thin film transistors

    SciTech Connect

    Hu, W.; Peterson, R. L.

    2014-05-12

    Amorphous oxide semiconductors are of increasing interest for a variety of thin film electronics applications. Here, the contact properties of different source/drain electrode materials to solution-processed amorphous zinc tin oxide (ZTO) thin-film transistors are studied using the transmission line method. The width-normalized contact resistance between ZTO and sputtered molybdenum is measured to be 8.7 Ω-cm, which is 10, 20, and 600 times smaller than that of gold/titanium, indium tin oxide, and evaporated molybdenum electrodes, respectively. The superior contact formed using sputtered molybdenum is due to a favorable work function lineup, an insulator-free interface, bombardment of ZTO during molybdenum sputtering, and trap-assisted tunneling. The transfer length of the sputtered molybdenum/ZTO contact is 0.34 μm, opening the door to future radio-frequency sub-micron molybdenum/ZTO thin film transistors.

  17. Diagnostics of RF magnetron sputtering plasma for synthesizing transparent conductive Indium-Zinc-Oxide film

    NASA Astrophysics Data System (ADS)

    Ohta, Takayuki; Inoue, Mari; Takota, Naoki; Ito, Masafumi; Higashijima, Yasuhiro; Kano, Hiroyuki; den, Shoji; Yamakawa, Koji; Hori, Masaru

    2009-10-01

    Transparent conductive Oxide film has been used as transparent conducting electrodes of optoelectronic devices such as flat panel display, solar cells, and so on. Indium-Zinc-Oxide (IZO) has been investigated as one of promising alternatives Indium Tin Oxide film, due to amorphous, no nodule and so on. In order to control a sputtering process with highly precise, RF magnetron sputtering plasma using IZO composite target was diagnosed by absorption and emission spectroscopy. We have developed a multi-micro hollow cathode lamp which can emit simultaneous multi-atomic lines for monitoring Zn and In densities simultaneously. Zn and In densities were measured to be 10^9 from 10^10 cm-3 at RF power from 40 to 100 W, pressure of 5Pa, and Ar flow rate of 300 sccm. The emission intensities of Zn, In, InO, and Ar were also observed.

  18. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)zinc species also form very stable complexes with the radicals Me(2)NCS(2)(*) and Me(2)NCS(3)(*). Dissociation of the TMTD molecule at the S-S bond on reaction with the Zn(4)O(4) cluster is predicted to be strongly exothermic, in sharp contrast to the endothermic S-S bond dissociation of the free molecule. The same holds for tetramethylthiuram trisulfide (TMTT). Surprisingly, the resulting complexes contain Zn-S as well as S-O bonds. The Zn(4)O(4) nanocluster serves here as a model for bulk zinc oxide used as an activator in rubber vulcanization by sulfur. The further uptake of sulfur atoms by the various complexes from S(8) or TMTD with formation of species derived from the radical Me(2)NCS(3)(*) or the trithiocarbamate anion Me(2)NCS(3)(-) is endothermic for mono- and dinuclear zinc dithiocarbamate (dtc) complexes such as [Zn(dtc)(2)] and [Zn(2)(dtc)(4)], but exothermic in the case of polynuclear zinc oxide species containing bridging ligands as in [Zn(4)O(4)(mu-S(2)CNMe(2))] and [Zn(4)O(4)(mu-dtc)]. Therefore, zinc oxide as a polynuclear species is predicted to promote the formation of trisulfido complexes, which are generally assumed to serve as catalysts for the transfer of

  19. Complexation of the vulcanization accelerator tetramethylthiuram disulfide and related molecules with zinc compounds including zinc oxide clusters (Zn4O4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Wong, Ming Wah

    2008-01-01

    Zinc chemicals are used as activators in the vulcanization of organic polymers with sulfur to produce elastic rubbers. In this work, the reactions of Zn(2+), ZnMe(2), Zn(OMe)(2), Zn(OOCMe)(2), and the heterocubane cluster Zn(4)O(4) with the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and with the related radicals and anions Me(2)NCS(2)(*), Me(2)NCS(3)(*), Me(2)NCS(2)(-), and Me(2)NCS(3)(-) have been studied by quantum chemical methods at the MP2/6-31+G(2df,p)//B3LYP/6-31+G* level of theory. More than 35 zinc complexes have been structurally characterized and the energies of formation from their components calculated for the first time. The binding energy of TMTD as a bidendate ligand increases in the order ZnMe(2)zinc species also form very stable complexes with the radicals Me(2)NCS(2)(*) and Me(2)NCS(3)(*). Dissociation of the TMTD molecule at the S-S bond on reaction with the Zn(4)O(4) cluster is predicted to be strongly exothermic, in sharp contrast to the endothermic S-S bond dissociation of the free molecule. The same holds for tetramethylthiuram trisulfide (TMTT). Surprisingly, the resulting complexes contain Zn-S as well as S-O bonds. The Zn(4)O(4) nanocluster serves here as a model for bulk zinc oxide used as an activator in rubber vulcanization by sulfur. The further uptake of sulfur atoms by the various complexes from S(8) or TMTD with formation of species derived from the radical Me(2)NCS(3)(*) or the trithiocarbamate anion Me(2)NCS(3)(-) is endothermic for mono- and dinuclear zinc dithiocarbamate (dtc) complexes such as [Zn(dtc)(2)] and [Zn(2)(dtc)(4)], but exothermic in the case of polynuclear zinc oxide species containing bridging ligands as in [Zn(4)O(4)(mu-S(2)CNMe(2))] and [Zn(4)O(4)(mu-dtc)]. Therefore, zinc oxide as a polynuclear species is predicted to promote the formation of trisulfido complexes, which are generally assumed to serve as catalysts for the transfer of

  20. [SEM/EDAX determination of zinc levels in dentin after administration of zinc oxide-eugenol paste].

    PubMed

    Pavlović, G; Jovanić, P

    1992-01-01

    The quantitative EDAX analysis of zinc contents was performed in the dentin samples of markedly different morphology after the use of ZOE paste in various time intervals. EDAX analysis has shown that samples of the ground dentin have high zinc content. The mean value of zinc content was 5.42% ten days after the use of ZOE paste and 19.16% after 30 days. Zinc content in samples of the polished dentin determined by EDAX analysis was significantly lower compared to that of the ground dentin. The presence of paste was not found on samples of the polished dentin ten days after the use of ZOE paste while after a 30-day treatment zinc content was only 1.29%.

  1. Effect of zinc and iron ions on the electrochemistry of nickel oxide electrode: Slow cyclic voltammetry. Technical report

    SciTech Connect

    Krejci, I.; Vanysek, P.

    1993-04-07

    Porous sintered nickel oxide electrodes were prepared by cathodic electroprecipitation from metal nitrate solutions and characterized by slow (0.1 mV/s) voltammetry in 6 mol/l KOH. Presence of iron or zinc ions resulted in decrease of electrode charging ability and similar changes in voltammograms were observed for both ions. Removal of iron or zinc ions and introduction of lithium ions partially restored the electrode and corresponding voltammogram to original conditions. Presence of cobalt in the electrode material diminished substantially the influence of zinc ions on the electrode properties.... Storage batteries, Power sources, Membrane transport, Ion transport, Nafion.

  2. Immobilization of anionic iron(III) porphyrins onto in situ obtained zinc oxide.

    PubMed

    Machado, Guilherme S; Wypych, Fernando; Nakagaki, Shirley

    2012-07-01

    A family of anionic iron(III) porphyrins (FePor) was immobilized onto zinc oxide (ZnO) obtained by the in situ hydrothermal decomposition of zinc hydroxide nitrate, a layered hydroxide salt. The immobilization probably occurred via the interaction between the anionic charges on the porphyrins and the positively charged surface of the ZnO, in slightly acidic to neutral pH. The resulting solids were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRDP), Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR), and ultraviolet-visible spectroscopy (UV-Vis) (solid samples), which confirmed the formation of ZnO and the immobilization of the FePor. The prepared materials were employed as catalysts for the heterogeneous catalytic oxidation of cyclooctene, cyclohexane, and n-heptane, using iodosylbenzene as the oxygen donor. Good catalytic results were achieved for all the substrates, and selectivity for the alcohol was verified during the oxidation of alkanes. The reuse capacity of the solid catalyst was also investigated.

  3. Reversible aqueous zinc/manganese oxide energy storage from conversion reactions

    NASA Astrophysics Data System (ADS)

    Pan, Huilin; Shao, Yuyan; Yan, Pengfei; Cheng, Yingwen; Han, Kee Sung; Nie, Zimin; Wang, Chongmin; Yang, Jihui; Li, Xiaolin; Bhattacharya, Priyanka; Mueller, Karl T.; Liu, Jun

    2016-05-01

    Rechargeable aqueous batteries such as alkaline zinc/manganese oxide batteries are highly desirable for large-scale energy storage owing to their low cost and high safety; however, cycling stability is a major issue for their applications. Here we demonstrate a highly reversible zinc/manganese oxide system in which optimal mild aqueous ZnSO4-based solution is used as the electrolyte, and nanofibres of a manganese oxide phase, α-MnO2, are used as the cathode. We show that a chemical conversion reaction mechanism between α-MnO2 and H+ is mainly responsible for the good performance of the system. This includes an operating voltage of 1.44 V, a capacity of 285 mAh g‑1 (MnO2), and capacity retention of 92% over 5,000 cycles. The Zn metal anode also shows high stability. This finding opens new opportunities for the development of low-cost, high-performance rechargeable aqueous batteries.

  4. Density Functional Theory Study of Atomic Layer Deposition of Zinc Oxide on Graphene

    NASA Astrophysics Data System (ADS)

    Ali, Amgad Ahmed; Hashim, Abdul Manaf

    2015-07-01

    The dissociation of zinc ions (Zn2+) from vapor-phase zinc acetylacetonate, Zn(C5H7O2)2, or Zn(acac)2 and its adsorption onto graphene oxide via atomic layer deposition (ALD) were studied using a quantum mechanics approach. Density functional theory (DFT) was used to obtain an approximate solution to the Schrödinger equation. The graphene oxide cluster model was used to represent the surface of the graphene film after pre-oxidation. In this study, the geometries of reactants, transition states, and products were optimized using the B3LYB/6-31G** level of theory or higher. Furthermore, the relative energies of the various intermediates and products in the gas-phase radical mechanism were calculated at the B3LYP/6-311++G** and MP2/6-311 + G(2df,2p) levels of theory. Additionally, a molecular orbital (MO) analysis was performed for the products of the decomposition of the Zn(acac)2 complex to investigate the dissociation of Zn2+ and the subsequent adsorption of H atoms on the C5H7O2 cluster to form acetylacetonate enol. The reaction energies were calculated, and the reaction mechanism was accordingly proposed. A simulation of infrared (IR) properties was performed using the same approach to support the proposed mechanism via a complete explanation of bond forming and breaking during each reaction step.

  5. Fabrication and characterization of one dimensional zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Cheng, Chun

    In this thesis, one dimensional (1D) ZnO nanostructures with controlled morphologies, defects and alignment have been fabricated by a simple vapor transfer method. The crystal structures, interfaces, growth mechanisms and optical properties of ZnO nanostructures have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Great efforts have been devoted to the patterned growth and assembly of ZnO nanostructures as well as the stability of ZnO nanowires (NWs). Using carbonized photoresists, a simple and very effective method has been developed for fabricating and patterning high-quality ZnO NW arrays. ZnO NWs from this method show excellent alignment, crystal quality, and optical properties that are independent of the substrates. The carbonized photoresists provide perfect nucleation sites for the growth of aligned ZnO NWs and also perfectly connect to the NWs to form ideal electrodes. This approach is further extended to realize large area growth of different forms of ZnO NW arrays (e.g., the horizontal growth and multilayered ZnO NW arrays) on other kinds of carbon-based materials. In addition, the as-synthesized vertically aligned ZnO NW arrays show a low weighted reflectance (Rw) and can be used as antireflection coatings. Moreover, non c-axis growth of 1D ZnO nanostructures (e.g., nanochains, nanobrushes and nanobelts) and defect related 1D ZnO nanostructures (e.g., Y-shaped twinned nanobelts and hierarchical nanostructures decorated by flowers induced by screw dislocations) is also present. Using direct oxidization of pure Zn at high temperatures in air, uniformed ZnO NWs and tetrapods have been fabricated. The spatially-resolved PL study on these two kinds of nanostructures suggests that the defects leading to the green luminescence (GL) should originate from the structural changes along the legs of the tetrapods. Surface defects in these ZnO nanostructures play an unimportant

  6. In-vitro antibacterial study of zinc oxide nanostructures on Streptococcus sobrinus

    NASA Astrophysics Data System (ADS)

    Bakhori, Siti Khadijah Mohd; Mahmud, Shahrom; Ann, Ling Chuo; Sirelkhatim, Amna; Hasan, Habsah; Mohamad, Dasmawati; Masudi, Sam'an Malik; Seeni, Azman; Rahman, Rosliza Abd

    2014-10-01

    Zinc oxide nanostructures were prepared using a pilot plant of zinc oxide boiling furnace. Generally, it produced two types of nanostructures different in morphology; one is rod-like shaped (ZnO-1) and a plate-like shape (ZnO-2). The properties of ZnO were studied by structural, optical and morphological using XRD, PL and FESEM respectively. The XRD patterns confirmed the wurtzite structures of ZnO with the calculated crystallite size of 41 nm (ZnO-1) and 42 nm (ZnO-2) using Scherrer formula. The NBE peaks were determined by photoluminescence spectra which reveal peak at 3.25 eV and 3.23 eV for ZnO-1 and ZnO-2 respectively. Prior to that, the morphologies for both ZnO-1 and ZnO-2 were demonstrated from FESEM micrographs. Subsequently the antibacterial study was conducted using in-vitro broth dilution technique towards a gram positive bacterium Streptococcus sobrinus (ATCC 33478) to investigate the level of antibacterial effect of zinc oxide nanostructures as antibacterial agent. Gradual increment of ZnO concentrations from 10-20 mM affected the inhibition level after twenty four hours of incubation. In conjunction with concentration increment of ZnO, the percentage inhibition towards Streptococcus sobrinus was also increased accordingly. The highest inhibition occurred at 20 mM of ZnO-1 and ZnO-2 for 98% and 77% respectively. It showed that ZnO has good properties as antibacterial agent and relevancy with data presented by XRD, PL and FESEM were determined.

  7. Decolorization of azo dyes in bioelectrochemical systems.

    PubMed

    Mu, Yang; Rabaey, Korneel; Rozendal, René A; Yuan, Zhiguo; Keller, Jürg

    2009-07-01

    Azo dyes are ubiquitously used in the textile industry. These dyes need to be removed from the effluent prior to discharge to sewage due to their intense color and toxicity. In this study we investigated the use of a bioelectrochemical system (BES) to abioticlly cathodic decolorization of a model azo dye, Acid Orange 7 (AO7), where the process was driven by microbial oxidation of acetate atthe anode. Effective decolorization of AO7 at rates up to 264 +/- 0.03 mol m(-3) NCC d(-1) (net cathodic compartment, NCC) was achieved at the cathode, with concomitant energy recovery. The AO7 decolorization rate was significantly enhanced when the BES was supplied with power, reaching 13.18 +/- 0.05 mol m(-3) NCC d(-1) at an energy consumption 0.012 +/- 0.001 kWh mol(-1) AO7 (at a controlled cathode potential of -400 mV vs SHE). Compared with conventional anaerobic biological methods, the required dosage of organic cosubstrate was significantly reduced in the BES. A possible cathodic reaction mechanism for the decolorization of AO7 is suggested based on the decolorization products identified: the azo bond of AO7 was cleaved at the cathode, resulting in the formation of the colorless sulfanilic acid and 1-amino-2-naphthol.

  8. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    SciTech Connect

    Guo, Li Qiang Ding, Jian Ning; Huang, Yu Kai; Zhu, Li Qiang

    2015-08-15

    Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO{sub 2} electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO) synaptic transistor. In such synaptic transistors, protons within the SiO{sub 2} electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF) behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  9. Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

    SciTech Connect

    Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M.

    2013-11-25

    We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

  10. Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures

    NASA Astrophysics Data System (ADS)

    Pooley, Kathryn J.; Joo, John H.; Hu, Evelyn L.

    2014-01-01

    We study low temperature (90 °C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.

  11. Growth mechanism of atomic layer deposition of zinc oxide: A density functional theory approach

    SciTech Connect

    Afshar, Amir; Cadien, Kenneth C.

    2013-12-16

    Atomic layer deposition of zinc oxide (ZnO) using diethylzinc (DEZ) and water is studied using density functional theory. The reaction pathways between the precursors and ZnO surface sites are discussed. Both reactions proceed by the formation of intermediate complexes on the surface. The Gibbs free energy of the formation of these complexes is positive at temperatures above ∼120 °C and ∼200 °C for DEZ and water half-reactions, respectively. Spectroscopic ellipsometry results show that the growth per cycle changes at approximately the same temperatures.

  12. Low-voltage protonic/electronic hybrid indium zinc oxide synaptic transistors on paper substrates

    NASA Astrophysics Data System (ADS)

    Wu, Guodong; Wan, Changjin; Zhou, Jumei; Zhu, Liqiang; Wan, Qing

    2014-03-01

    Low-voltage (1.5 V) indium zinc oxide (IZO)-based electric-double-layer (EDL) thin-film transistors (TFTs) gated by nanogranular proton conducting SiO2 electrolyte films are fabricated on paper substrates. Both enhancement-mode and depletion-mode operation are obtained by tuning the thickness of the IZO channel layer. Furthermore, such flexible IZO protonic/electronic hybrid EDL TFTs can be used as artificial synapses, and synaptic stimulation response and short-term synaptic plasticity function are demonstrated. The protonic/electronic hybrid EDL TFTs on paper substrates proposed here are promising for low-power flexible paper electronics, artificial synapses and bioelectronics.

  13. Rapid deposition process for zinc oxide film applications in pyroelectric devices

    NASA Astrophysics Data System (ADS)

    Hsiao, Chun-Ching; Yu, Shih-Yuan

    2012-10-01

    Aerosol deposition (AD) is a rapid process for the deposition of films. Zinc oxide is a low toxicity and environmentally friendly material, and it possesses properties such as semiconductivity, pyroelectricity and piezoelectricity without the poling process. Therefore, AD is used to accelerate the manufacturing process for applications of ZnO films in pyroelectric devices. Increasing the temperature variation rate in pyroelectric films is a useful method for enhancing the responsivity of pyroelectric devices. In the present study, a porous ZnO film possessing the properties of large heat absorption and high temperature variation rate is successfully produced by the AD rapid process and laser annealing for application in pyroelectric devices.

  14. Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposite.

    PubMed

    Namvar, Farideh; Azizi, Susan; Rahman, Heshu Sulaiman; Mohamad, Rosfarizan; Rasedee, Abdullah; Soltani, Mozhgan; Rahim, Raha Abdul

    2016-01-01

    The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO) nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet-vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1), ovarian adenocarcinoma (CaOV-3), colonic adenocarcinoma (COLO205), and acute promyelocytic leukemia (HL-60) cells were treated with HA/ZnO nanocomposite. At 72 hours of treatment, the half maximal inhibitory concentration (IC50) value via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 10.8±0.3 μg/mL, 15.4±1.2 μg/mL, 12.1±0.9 μg/mL, and 6.25±0.5 μg/mL for the PANC-1, CaOV-3, COLO-205, and HL-60 cells, respectively, showing that the composite is most toxic to the HL-60 cells. On the other hand, HA/ZnO nanocomposite treatment for 72 hours did not cause toxicity to the normal human lung fibroblast (MRC-5) cell line. Using fluorescent dyes and flow cytometry analysis, HA/ZnO nanocomposite caused G2/M cell cycle arrest and stimulated apoptosis-related increase in caspase-3 and -7 activities of the HL-60 cells. Thus, the study shows that the HA/ZnO nanocomposite produced through green synthesis has great potential to be developed into an efficacious therapeutic agent for cancers. PMID:27555781

  15. Surfactant Assisted Sonochemical Synthesis and Characterization of Gadolinium Doped Zinc Oxide Nanoparticles.

    PubMed

    Khajuria, Heena; Ladol, Jigmet; Singh, Rajinder; Khajuria, Sonika; Khajuria, Haq N

    2015-01-01

    Pure and Gd doped Zinc Oxide (ZnO) nanoparticles were synthesized by sonochemical method using different surfactants (PVP/CTAB). The nanoparticles were characterized by powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), particle size analysis by DLS technique and UV-Visible spectroscopy. The effect of Gd doping and nature of surfactants on crystallite size, morphology and band gap of ZnO nanoparticles have been investigated. In addition to this, the effect of nature of surfactant on amount of dopant inserted in the ZnO lattice was also studied.

  16. Photoelectrochemical cell using dye sensitized zinc oxide nanowires grown on carbon fibers

    NASA Astrophysics Data System (ADS)

    Unalan, Husnu Emrah; Wei, Di; Suzuki, Kenichi; Dalal, Sharvari; Hiralal, Pritesh; Matsumoto, Hidetoshi; Imaizumi, Shinji; Minagawa, Mie; Tanioka, Akihiko; Flewitt, Andrew J.; Milne, William I.; Amaratunga, Gehan A. J.

    2008-09-01

    Zinc oxide (ZnO) nanowires (NWs) grown on carbon fibers using a vapor transport and condensation approach are used as the cathode of a photoelectrochemical cell. The carbon fibers were obtained by electrospray deposition and take the form of a flexible carbon fabric. The ZnO NW on carbon fiber anode is combined with a "black dye" photoabsorber, an electrolyte, and a platinum (Pt) counterelectrode to complete the cell. The results show that ZnO NW and carbon fibers can be used for photoinduced charge separation/charge transport and current collection, respectively, in a photoelectrochemical cell.

  17. Origin of ferromagnetism enhancement in bi-layer chromium-doped indium zinc oxides

    SciTech Connect

    Hsu, C. Y.

    2012-08-06

    This work demonstrates that by controlling the rapid thermal annealing temperature, amorphous chromium-doped indium zinc oxide films develop an amorphous-crystalline bi-layer structure and show magnetization up to {approx}30 emu/cm{sup 3}. The crystalline layer arises from significant out-diffusion of Zn from surfaces, leading to a large difference in the Zn:In ratio in amorphous and crystalline layers. Doped Cr ions in amorphous and crystalline layers form different valence configurations, creating a charge reservoir which transfers electrons through amorphous-crystalline interfaces and in turn enhances ferromagnetism.

  18. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    NASA Astrophysics Data System (ADS)

    Guo, Li Qiang; Zhu, Li Qiang; Ding, Jian Ning; Huang, Yu Kai

    2015-08-01

    Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO2 electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO) synaptic transistor. In such synaptic transistors, protons within the SiO2 electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF) behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  19. Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

    SciTech Connect

    El-Said, A. S. E-mail: a.s.el-said@hzdr.de; Moslem, W. M.; Djebli, M.

    2014-06-09

    Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

  20. AChE biosensor based on zinc oxide sol-gel for the detection of pesticides.

    PubMed

    Sinha, Ravi; Ganesana, Mallikarjunarao; Andreescu, Silvana; Stanciu, Lia

    2010-02-28

    Zinc oxide has been used as a matrix for immobilization of acetylcholinesterase (AChE) and detection of the pesticide paraoxon. The immobilized enzyme retained its enzymatic activity up to three months when stored in phosphate buffered saline (pH 7.4) at 4 degrees C. An amperometric biosensor for the detection of paraoxon was designed. The biosensor detected paraoxon in the range 0.035-1.38 ppm and can be used to detect other AChE inhibiting organophosphate pesticides. PMID:20113735

  1. Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures

    SciTech Connect

    Pooley, Kathryn J. Joo, John H.; Hu, Evelyn L.

    2014-01-01

    We study low temperature (90 °C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.

  2. 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.

  3. Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposite

    PubMed Central

    Namvar, Farideh; Azizi, Susan; Rahman, Heshu Sulaiman; Mohamad, Rosfarizan; Rasedee, Abdullah; Soltani, Mozhgan; Rahim, Raha Abdul

    2016-01-01

    The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO) nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet–vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1), ovarian adenocarcinoma (CaOV-3), colonic adenocarcinoma (COLO205), and acute promyelocytic leukemia (HL-60) cells were treated with HA/ZnO nanocomposite. At 72 hours of treatment, the half maximal inhibitory concentration (IC50) value via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 10.8±0.3 μg/mL, 15.4±1.2 μg/mL, 12.1±0.9 μg/mL, and 6.25±0.5 μg/mL for the PANC-1, CaOV-3, COLO-205, and HL-60 cells, respectively, showing that the composite is most toxic to the HL-60 cells. On the other hand, HA/ZnO nanocomposite treatment for 72 hours did not cause toxicity to the normal human lung fibroblast (MRC-5) cell line. Using fluorescent dyes and flow cytometry analysis, HA/ZnO nanocomposite caused G2/M cell cycle arrest and stimulated apoptosis-related increase in caspase-3 and -7 activities of the HL-60 cells. Thus, the study shows that the HA/ZnO nanocomposite produced through green synthesis has great potential to be developed into an efficacious therapeutic agent for cancers. PMID:27555781

  4. Superhydrophobic surfaces using selected zinc oxide microrod growth on ink-jetted patterns.

    PubMed

    Myint, Myo Tay Zar; Kitsomboonloha, Rungrot; Baruah, Sunandan; Dutta, Joydeep

    2011-02-15

    The synthesis and properties of superhydrophobic surfaces based on binary surface topography made of zinc oxide (ZnO) microrod-decorated micropatterns are reported. ZnO is intrinsically hydrophilic but can be utilized to create hydrophobic surfaces by creating artificial roughness via microstructuring. Micron scale patterns consisting of nanocrystalline ZnO seed particles were applied to glass substrates with a modified ink-jet printer. Microrods were then grown on the patterns by a hydrothermal process without any further chemical modification. Water contact angle (WCA)(1) up to 153° was achieved. Different micro array patterned surfaces with varying response of static contact angle or sessile droplet analysis are reported.

  5. The reduction and distillation of isotopically enriched zinc oxides under high vacuum conditions

    NASA Astrophysics Data System (ADS)

    Marcus, C.; Zevenbergen, L. A.

    1999-12-01

    Historically, enriched zinc (Zn) metal was produced at the Oak Ridge National Laboratory's Isotope Enrichment Facility (IEF) by either electrodeposition, followed by melting to produce a metal ingot, or purified by hydrogen reduction and distillation at atmospheric pressure in a tube furnace as a prelude to electroplating. Electroplated material was generally poor in quality, and losses were high during subsequent melting. Adapting the distillation purifying technique as an ultimate means of recovery of Zn metal proved to be difficult and inefficient. To resolve these problems, the well-established vacuum reduction/distillation process was adapted for the conversion of Zn oxide to metal.

  6. Chondroprotective effect of zinc oxide nanoparticles in conjunction with hypoxia on bovine cartilage-matrix synthesis.

    PubMed

    Mirza, Eraj Humayun; Pan-Pan, Chong; Wan Ibrahim, Wan Mohd Azhar Bin; Djordjevic, Ivan; Pingguan-Murphy, Belinda

    2015-11-01

    Articular cartilage is a tissue specifically adapted to a specific niche with a low oxygen tension (hypoxia), and the presence of such conditions is a key factor in regulating growth and survival of chondrocytes. Zinc deficiency has been linked to cartilage-related disease, and presence of Zinc is known to provide antibacterial benefits, which makes its inclusion attractive in an in vitro system to reduce infection. Inclusion of 1% zinc oxide nanoparticles (ZnONP) in poly octanediol citrate (POC) polymer cultured in hypoxia has not been well determined. In this study we investigated the effects of ZnONP on chondrocyte proliferation and matrix synthesis cultured under normoxia (21% O2 ) and hypoxia (5% O2 ). We report an upregulation of chondrocyte proliferation and sulfated glycosaminoglycan (S-GAG) in hypoxic culture. Results demonstrate a synergistic effect of oxygen concentration and 1% ZnONP in up-regulation of anabolic gene expression (Type II collagen and aggrecan), and a down regulation of catabolic (MMP-13) gene expression. Furthermore, production of transcription factor hypoxia-inducible factor 1A (HIF-1A) in response to hypoxic condition to regulate chondrocyte survival under hypoxia is not affected by the presence of 1% ZnONP. Presence of 1% ZnONP appears to act to preserve homeostasis of cartilage in its hypoxic environment.

  7. 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.

  8. First-principles study of negative thermal expansion in zinc oxide

    NASA Astrophysics Data System (ADS)

    Wang, Zhanyu; Wang, Fei; Wang, Lei; Jia, Yu; Sun, Qiang

    2013-08-01

    We present the first-principles calculations of vibrational and thermal properties for wurtzite and zinc-blende zinc oxide (ZnO) within DFT and quasi-harmonic approximation, especially for their negative thermal expansion (NTE) behavior. For the wurtzite and zinc-blende phases, negative thermal expansions are obtained at T < 95 K and T < 84 K, respectively. For the wurtzite structure, calculated phonon frequencies and mode Grüneisen parameters of low-energy modes are in good agreement with that determined experimentally. And the thermal expansion coefficient is found to be in good agreement with the experimental results. Like many other NTE semiconductors, detailed study of both phases shows that maximum contribution to NTE comes from low-frequency transverse acoustic modes, while for the wurtzite structure the contribution of longitudinal acoustic and lowest-energy optical modes is not ignorable. From the specific analysis of the vibration modes, we found that the negative thermal expansion in ZnO is dominated by the tension effect.

  9. Analysis of indium zinc oxide thin films by laser-induced breakdown spectroscopy

    SciTech Connect

    Popescu, A. C.; Beldjilali, S.; Socol, G.; Mihailescu, I. N.; Craciun, V.; Hermann, J.

    2011-10-15

    We have performed spectroscopic analysis of the plasma generated by Nd:YAG ({lambda} = 266 nm) laser irradiation of thin indium zinc oxide films with variable In content deposited by combinatorial pulsed laser deposition on glass substrates. The samples were irradiated in 5 x 10{sup 4} Pa argon using laser pulses of 5 ns duration and 10 mJ energy. The plasma emission spectra were recorded with an Echelle spectrometer coupled to a gated detector with different delays with respect to the laser pulse. The relative concentrations of indium and zinc were evaluated by comparing the measured spectra to the spectral radiance computed for a plasma in local thermal equilibrium. Plasma temperature and electron density were deduced from the relative intensities and Stark broadening of spectral lines of atomic zinc. Analyses at different locations on the deposited thin films revealed that the In/(In + Zn) concentration ratio significantly varies over the sample surface, from 0.4 at the borders to about 0.5 in the center of the film. The results demonstrate that laser-induced breakdown spectroscopy allows for precise and fast characterization of thin films with variable composition.

  10. Zinc thiolate reactivity toward nitrogen oxides: insights into the interaction of Zn2+ with S-nitrosothiols and implications for nitric oxide synthase.

    PubMed

    Kozhukh, Julia; Lippard, Stephen J

    2012-07-01

    Zinc thiolate complexes containing N(2)S tridentate ligands were prepared to investigate their reactivity toward reactive nitrogen species, chemistry proposed to occur at the zinc tetracysteine thiolate site of nitric oxide synthase (NOS). The complexes are unreactive toward nitric oxide (NO) in the absence of dioxygen, strongly indicating that NO cannot be the species directly responsible for S-nitrosothiol formation and loss of Zn(2+) at the NOS dimer interface in vivo. S-Nitrosothiol formation does occur upon exposure of zinc thiolate solutions to NO in the presence of air, however, or to NO(2) or NOBF(4), indicating that these reactive nitrogen/oxygen species are capable of liberating zinc from the enzyme, possibly through generation of the S-nitrosothiol. Interaction between simple Zn(2+) salts and preformed S-nitrosothiols leads to decomposition of the -SNO moiety, resulting in release of gaseous NO and N(2)O. The potential biological relevance of this chemistry is discussed.

  11. Enhanced violet photoemission of nanocrystalline fluorine doped zinc oxide (FZO) thin films

    NASA Astrophysics Data System (ADS)

    Anusha, Muthukumar; Arivuoli, D.; Manikandan, E.; Jayachandran, M.

    2015-09-01

    Highly stable fluorine doped nanocrystalline zinc oxide thin films were prepared on corning glass substrates by aerosol assisted chemical vapor deposition (AACVD) at variable deposition temperature of 360 °C, 380 °C and 420 °C. Especially, the optimum deposition temperature was investigated for high intense violet emission. The film crystallinity improved with the increasing deposition temperature and highly textured film was obtained at 420 °C. The films exhibited surface morphology variation from spherical to platelets due to deposition temperature effect, analyzed by field emission scanning electron microscope (FE-SEM). Higher growth rate observed at 420 °C which leads larger grains and lowest resistivity of ∼5.77 Ω cm among the deposited films which may be due to reduction in zinc vacancies and grain boundary area. Zinc vacancies are acts as electron killer centres. UV-visible spectra indicated higher transmittance (83-90%) in the visible region. Red shift of optical absorption edges associated with the increase in particle size consistent well with the XRD results. Reduced E2(high) intensity was observed in Raman spectra, for the film deposited at 380 °C which indicates decreased oxygen incorporation confirmed by PL spectra. Especially, enhanced violet emission observed at 3.06 eV for the films deposited at 380 °C due to electronic transition from the defect level of zinc vacancies to the conduction band, probably attributed to enhanced incorporation of 'F' into 'O' sites associated with increased Zn vacancies and also decreased oxygen incorporation consistent with the electrical and Raman analyses.

  12. Hybrid transparent conductive electrodes with copper nanowires embedded in a zinc oxide matrix and protected by reduced graphene oxide platelets

    NASA Astrophysics Data System (ADS)

    Zhu, Zhaozhao; Mankowski, Trent; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

    2016-02-01

    Transparent conductive electrodes (TCE) were fabricated by combining three emerging nano-materials: copper nanowires (CuNWs), zinc oxide (ZnO) nano-particulate thin films, and reduced graphene oxide (rGO) platelets. Whereas CuNWs are responsible for essentially all of the electrical conductivity of our thin-film TCEs, the ZnO matrix embeds and strengthens the CuNW network in its adhesion to the substrate, while the rGO platelets provide a protective overcoat for the composite electrode, thereby improving its stability in hot and humid environments. Our CuNW/ZnO/rGO hybrid electrodes deposited on glass substrates have low sheet resistance (Rs ˜ 20 Ω/sq) and fairly high optical transmittance (T550 ˜ 79%). In addition, our hybrid TCEs are mechanically strong and able to withstand multiple scotch-tape peel tests. Finally, these TCEs can be fabricated on rigid glass as well as flexible plastic substrates.

  13. 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.

  14. Mechanism of azo dye degradation in Advanced Oxidation Processes: Degradation of Sulfanilic Acid Azochromotrop and its parent compounds in aqueous solution by ionizing radiation

    NASA Astrophysics Data System (ADS)

    Pálfi, Tamás; Wojnárovits, László; Takács, Erzsébet

    2011-03-01

    Mechanistic studies were made on hydroxyl radical and hydrated electron reaction with Sulfanilic Acid Azochromotrop (SPADNS) as model azo dye in dilute aqueous solution. SPADNS contains 4,5-dihydroxynaphthalene-2,7-disulfonic acid part and 4-sulfophenylazo group. To establish the details of the reaction mechanism the reactions of two simpler molecules without 4-sulfophenylazo part were also studied: one of them contained one (in position 4, II), the other two (in positions 4 and 5, III) -OH groups. Hydroxyl radicals react with these molecules with radical addition to the naphthalene-2,7-disulfonic acid part. The adduct hydroxycyclohexadienyl type radical decays in radical-radical reactions, or undergoes a (pH dependent) water elimination to yield naphthoxy radical. The radical decay takes place on the ms timescale. Degradation efficiencies are 0.6-0.8. Hydrated electron in the case of the two simpler molecules reacts with the rings, while in the case of dye with the azo bond. Electron scavenging is followed by protonation, this reaction in the case of II and III yields cyclohexadienyl, while with the dye hydrazo radical. The efficiency of degradation with II and III is 0.2-0.6, while for SPADNS it is close to 1.

  15. Plasmon resonance and perfect light absorption in subwavelength trench arrays etched in gallium-doped zinc oxide film

    SciTech Connect

    Hendrickson, Joshua R. Leedy, Kevin; Cleary, Justin W.; Vangala, Shivashankar; Nader, Nima; Guo, Junpeng

    2015-11-09

    Near-perfect light absorption in subwavelength trench arrays etched in highly conductive gallium-doped zinc oxide films was experimentally observed in the mid infrared regime. At wavelengths corresponding to the resonant excitation of surface plasmons, up to 99% of impinging light is efficiently trapped and absorbed in the periodic trenches. Scattering cross sectional calculations reveal that each individual trench acts like a vertical split ring resonator with a broad plasmon resonance spectrum. The coupling of these individual plasmon resonators in the grating structure leads to enhanced photon absorption and significant resonant spectral linewidth narrowing. Ellipsometry measurements taken before and after device fabrication result in different permittivity values for the doped zinc oxide material, indicating that localized annealing occurred during the plasma etching process due to surface heating. Simulations, which incorporate a 50 nm annealed region at the zinc oxide surface, are in a good agreement with the experimental results.

  16. Epitaxial growth of zinc oxide by the method of atomic layer deposition on SiC/Si substrates

    NASA Astrophysics Data System (ADS)

    Kukushkin, S. A.; Osipov, A. V.; Romanychev, A. I.

    2016-07-01

    For the first time, zinc oxide epitaxial films on silicon were grown by the method of atomic layer deposition at a temperature T = 250°C. In order to avoid a chemical reaction between silicon and zinc oxide (at the growth temperature, the rate constant of the reaction is of the order of 1022), a high-quality silicon carbide buffer layer with a thickness of ~50 nm was preliminarily synthesized by the chemical substitution of atoms on the silicon surface. The zinc oxide films were grown on n- and p-type Si(100) wafers. The ellipsometric, Raman, electron diffraction, and trace element analyses showed that the ZnO films are epitaxial.

  17. Plasmon resonance and perfect light absorption in subwavelength trench arrays etched in gallium-doped zinc oxide film

    NASA Astrophysics Data System (ADS)

    Hendrickson, Joshua R.; Vangala, Shivashankar; Nader, Nima; Leedy, Kevin; Guo, Junpeng; Cleary, Justin W.

    2015-11-01

    Near-perfect light absorption in subwavelength trench arrays etched in highly conductive gallium-doped zinc oxide films was experimentally observed in the mid infrared regime. At wavelengths corresponding to the resonant excitation of surface plasmons, up to 99% of impinging light is efficiently trapped and absorbed in the periodic trenches. Scattering cross sectional calculations reveal that each individual trench acts like a vertical split ring resonator with a broad plasmon resonance spectrum. The coupling of these individual plasmon resonators in the grating structure leads to enhanced photon absorption and significant resonant spectral linewidth narrowing. Ellipsometry measurements taken before and after device fabrication result in different permittivity values for the doped zinc oxide material, indicating that localized annealing occurred during the plasma etching process due to surface heating. Simulations, which incorporate a 50 nm annealed region at the zinc oxide surface, are in a good agreement with the experimental results.

  18. Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

    PubMed

    Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

    2012-01-17

    Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions.

  19. Evaluation of the effects of topical tripeptide-copper complex and zinc oxide on open-wound healing in rabbits.

    PubMed

    Cangul, I Taci; Gul, Nihal Y; Topal, Ayse; Yilmaz, Rahsan

    2006-12-01

    In this study the clinical and histopathological effects of topically applied tripeptide-copper complex (TCC) and zinc oxide on open-wound healing in rabbits was evaluated. Eighteen New Zealand rabbits were divided into three groups: TCC, zinc oxide and no treatment. One full thickness wound was created on each side of the dorsal midline in each rabbit. Wound margins were traced on days 0, 7, 14, and 21 and topical TCC and zinc oxide were applied daily for 21 days to each rabbit in the respective treatment groups. The mean unhealed wound area was significantly smaller in the TCC than in the zinc oxide group on day 7, but it was significantly smaller in the TCC group than in to the control group on days 7, 14 and 21. The mean percentage of wound contraction on day 7 was significantly higher in the TCC than in the zinc oxide group; however, it was significantly higher in the TCC group than in the control group on days 7, 14 and 21. Median time for the coverage of the wound bed with granulation tissue was significantly shorter in the TCC group than in the other groups. Filling of the open wound with granulation tissue to skin level was significantly slower in the control group than in the other two groups. Neutrophil counts decreased regardless of the group in parallel with healing, while neovascularization was best observed in the TCC group. The results suggest that TCC is a better choice in the treatment protocols of open wounds in rabbits than zinc oxide. PMID:17083573

  20. A sudden death with lung embolism after inadvertent infusion of zinc oxide shake lotion.

    PubMed

    Pragst, Fritz; Correns, Andreas; Priem, Friedrich; Herre, Sieglinde; Martin, Hubert

    2007-08-01

    A 74-year old woman in postoperative treatment after a colonic surgery died immediately after perfusion of about 1.5 mL of a white emulsion which was believed to contain 1% propofol via cardiac catheter into the right atrium. It was strongly suspected that a syringe with a zinc oxide shake lotion (consisting of 20% ZnO, 20% talc, 25% glycerol and 35% water) which was intended for external treatment had been mistaken for the propofol syringe. During autopsy, an anatomic cause of death could not be found. In order to exclude an intoxication and to determine the significance of the perfusion fluid in this context, toxicological and histological investigations were performed. Propofol and other drugs applied to the patient were found in therapeutic or sub-therapeutic range. However, in comparison to a control case, the zinc concentrations determined by AAS were about 200 times higher in lung tissue, 10 times higher in heart blood and 3-4 times higher in kidney and liver tissue. No increase was seen in venous blood. Histology showed a strong embolism of the lung tissue with birefingent sharp-edged crystals, which were identified as the talcum, and an amorphous component (ZnO). The same embolism was seen to a medium extent also in the brain sections and to a low extent in heart, liver, pancreas and kidney. Pulmonary embolism by talcum and zinc oxide was established as the cause of death which occurred by syringe swap due to insufficient security precautions in the drug administration. The results are discussed in context of pulmonary microembolism cases frequently described for drug addicts after injection of crashed talcum containing tablets.