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. Copyright © 2014. Published by Elsevier B.V.

Differential sensitivities of cellular XPA and PARP-1 to arsenite inhibition and zinc rescue.

PubMed

Ding, Xiaofeng; Zhou, Xixi; Cooper, Karen L; Huestis, Juliana; Hudson, Laurie G; Liu, Ke Jian

2017-09-15

Arsenite directly binds to the zinc finger domains of the DNA repair protein poly (ADP ribose) polymerase (PARP)-1, and inhibits PARP-1 activity in the base excision repair (BER) pathway. PARP inhibition by arsenite enhances ultraviolet radiation (UVR)-induced DNA damage in keratinocytes, and the increase in DNA damage is reduced by zinc supplementation. However, little is known about the effects of arsenite and zinc on the zinc finger nucleotide excision repair (NER) protein xeroderma pigmentosum group A (XPA). In this study, we investigated the difference in response to arsenite exposure between XPA and PARP-1, and the differential effectiveness of zinc supplementation in restoring protein DNA binding and DNA damage repair. Arsenite targeted both XPA and PARP-1 in human keratinocytes, resulting in zinc loss from each protein and a pronounced decrease in XPA and PARP-1 binding to chromatin as demonstrated by Chip-on-Western assays. Zinc effectively restored DNA binding of PARP-1 and XPA to chromatin when zinc concentrations were equal to those of arsenite. In contrast, zinc was more effective in rescuing arsenite-augmented direct UVR-induced DNA damage than oxidative DNA damage. Taken together, our findings indicate that arsenite interferes with PARP-1 and XPA binding to chromatin, and that zinc supplementation fully restores DNA binding activity to both proteins in the cellular context. Interestingly, rescue of arsenite-inhibited DNA damage repair by supplemental zinc was more sensitive for DNA damage repaired by the XPA-associated NER pathway than for the PARP-1-dependent BER pathway. This study expands our understanding of arsenite's role in DNA repair inhibition and co-carcinogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Zinc supplementation alleviates the progression of diabetic nephropathy by inhibiting the overexpression of oxidative-stress-mediated molecular markers in streptozotocin-induced experimental rats.

PubMed

Barman, Susmita; Pradeep, Seetur R; Srinivasan, Krishnapura

2018-04-01

Zinc deficiency during diabetes projects a role for zinc nutrition in the management of diabetic nephropathy. The current study explored whether zinc supplementation protects against diabetic nephropathy through modulation of kidney oxidative stress and stress-induced expression related to the inflammatory process in streptozotocin-induced diabetic rats. Groups of hyperglycemic rats were exposed to dietary interventions for 6 weeks with zinc supplementation (5 times and 10 times the normal level). Supplemental-zinc-fed diabetic groups showed a significant reversal of increased kidney weight and creatinine clearance. There was a significant reduction in hyperlipidemic condition along with improved PUFA:SFA ratio in the renal tissue. Expression of the lipid oxidative marker and expression of inflammatory markers, cytokines, fibrosis factors and apoptotic regulatory proteins observed in diabetic kidney were beneficially modulated by zinc supplementation, the ameliorative effect being concomitant with elevated antiapoptosis. There was a significant reduction in advanced glycation, expression of the receptor of the glycated products and oxidative stress markers. Zinc supplementation countered the higher activity and expression of polyol pathway enzymes in the kidney. Overexpression of the glucose transporters, as an adaptation to the increased need for glucose transport in diabetic condition, was minimized by zinc treatment. The pathological abnormalities in the renal architecture of diabetic animals were corrected by zinc intervention. Thus, dietary zinc supplementation has a significant beneficial effect in the control of diabetic nephropathy. This was exerted through a protective influence on oxidative-stress-induced cytokines, inflammatory proliferation and consequent renal injury. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm

PubMed Central

Al-Shabib, Nasser A.; Husain, Fohad Mabood; Ahmed, Faheem; Khan, Rais Ahmad; Ahmad, Iqbal; Alsharaeh, Edreese; Khan, Mohd Shahnawaz; Hussain, Afzal; Rehman, Md Tabish; Yusuf, Mohammad; Hassan, Iftekhar; Khan, Javed Masood; Ashraf, Ghulam Md; Alsalme, Ali Mohammed; Al-Ajmi, Mohamed F.; Tarasov, Vadim V.; Aliev, Gjumrakch

2016-01-01

Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative. PMID:27917856

Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm.

PubMed

Al-Shabib, Nasser A; Husain, Fohad Mabood; Ahmed, Faheem; Khan, Rais Ahmad; Ahmad, Iqbal; Alsharaeh, Edreese; Khan, Mohd Shahnawaz; Hussain, Afzal; Rehman, Md Tabish; Yusuf, Mohammad; Hassan, Iftekhar; Khan, Javed Masood; Ashraf, Ghulam Md; Alsalme, Ali Mohammed; Al-Ajmi, Mohamed F; Tarasov, Vadim V; Aliev, Gjumrakch

2016-12-05

Bacterial spoilage of food products is regulated by density dependent communication system called quorum sensing (QS). QS control biofilm formation in numerous food pathogens and Biofilms formed on food surfaces act as carriers of bacterial contamination leading to spoilage of food and health hazards. Agents inhibiting or interfering with bacterial QS and biofilm are gaining importance as a novel class of next-generation food preservatives/packaging material. In the present study, Zinc nanostructures were synthesised using Nigella sativa seed extract (NS-ZnNPs). Synthesized nanostructures were characterized hexagonal wurtzite structure of size ~24 nm by UV-visible, XRD, FTIR and TEM. NS-ZnNPs demonstrated broad-spectrum QS inhibition in C. violaceum and P. aeruginosa biosensor strains. Synthesized nanostructures inhibited QS regulated functions of C. violaceum CVO26 (violacein) and elastase, protease, pyocyanin and alginate production in PAO1 significantly. NS-ZnNPs at sub-inhibitory concentrations inhibited the biofilm formation of four-food pathogens viz. C. violaceum 12472, PAO1, L. monocytogenes, E. coli. Moreover, NS-ZnNPs was found effective in inhibiting pre-formed mature biofilms of the four pathogens. Therefore, the broad-spectrum inhibition of QS and biofilm by biogenic Zinc oxide nanoparticles and it is envisaged that these nontoxic bioactive nanostructures can be used as food packaging material and/or as food preservative.

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

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

Wang, Yu; Mei, Xueting; Yuan, Jingquan

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions inmore » serum Zn{sup 2+} and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase{sup +} was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights: • Dissolution of taurine zinc complex can be increased by solid dispersions (SDs). • Taurine zinc SDs blocked doxorubicin-induced hepatotoxicity and cardiotoxicity. • Taurine zinc SDs can alleviate oxidative stress and dampen JNK phosphorylation. • Taurine zinc SDs increased the expression of UGT, HO-1 at mRNA and protein level. • Taurine zinc SDs revealed greater hepatoprotective effects than silymarin.« less

Electrical properties of zinc-oxide-based thin-film transistors using strontium-oxide-doped semiconductors

NASA Astrophysics Data System (ADS)

Wu, Shao-Hang; Zhang, Nan; Hu, Yong-Sheng; Chen, Hong; Jiang, Da-Peng; Liu, Xing-Yuan

2015-10-01

Strontium-zinc-oxide (SrZnO) films forming the semiconductor layers of thin-film transistors (TFTs) are deposited by using ion-assisted electron beam evaporation. Using strontium-oxide-doped semiconductors, the off-state current can be dramatically reduced by three orders of magnitude. This dramatic improvement is attributed to the incorporation of strontium, which suppresses carrier generation, thereby improving the TFT. Additionally, the presence of strontium inhibits the formation of zinc oxide (ZnO) with the hexagonal wurtzite phase and permits the formation of an unusual phase of ZnO, thus significantly changing the surface morphology of ZnO and effectively reducing the trap density of the channel. Project supported by the National Natural Science Foundation of China (Grant No. 6140031454) and the Innovation Program of Chinese Academy of Sciences and State Key Laboratory of Luminescence and Applications.

Zinc rescues obesity-induced cardiac hypertrophy via stimulating metallothionein to suppress oxidative stress-activated BCL10/CARD9/p38 MAPK pathway.

PubMed

Wang, Shudong; Gu, Junlian; Xu, Zheng; Zhang, Zhiguo; Bai, Tao; Xu, Jianxiang; Cai, Jun; Barnes, Gregory; Liu, Qiu-Ju; Freedman, Jonathan H; Wang, Yonggang; Liu, Quan; Zheng, Yang; Cai, Lu

2017-06-01

Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Levels of semenogelin in human spermatozoa decrease during capacitation: involvement of reactive oxygen species and zinc.

PubMed

de Lamirande, E; Lamothe, G

2010-07-01

Semenogelin (Sg), the main protein of human semen coagulum, prevents sperm capacitation. The objective of this study was to examine the role of Sg and its mechanism of action. Sg blocked sperm capacitation triggered by various stimuli, via inhibition of superoxide anion (O(2)*-; luminescence assay) and nitric oxide (NO*; tested using diaminofluorescein) generation. Triton-soluble and -insoluble sperm fractions contained Sg and Sg peptides (immunoblotting), the level of which decreased with initiation of capacitation. This drop was prevented by superoxide dismutase and NO* synthase inhibitor and was reproduced by addition of O(2)*- and NO*. Zinc (Zn(2+)) blocked and a zinc chelator (TPEN) promoted the decline in Sg levels. There was a decreased labelling of Sg on the head in capacitating spermatozoa with the two fixation techniques tested (immunocytochemistry). Reactive oxygen species (ROS) (O(2)*- and NO*) caused, these changes, and zinc prevented them. Spermatozoa quickly internalized Sg upon incubation and Sg was then rapidly degraded in a zinc-inhibitable manner. Sg blocked capacitation mainly via inhibition of ROS generation. Spermatozoa appeared permeable to Sg and processed Sg in a zinc-inhibitable fashion. ROS themselves could promote sperm disposal of Sg which maybe one of the mechanisms that allows initiation of capacitation.

Effects of the essential metals copper and zinc in two freshwater detritivores species: Biochemical approach.

PubMed

Quintaneiro, C; Ranville, J; Nogueira, A J A

2015-08-01

The input of metals into freshwater ecosystems from natural and anthropogenic sources impairs water quality and can lead to biological alterations in organisms and plants, compromising the structure and the function of these ecosystems. Biochemical biomarkers may provide early detection of exposure to contaminants and indicate potential effects at higher levels of biological organisation. The effects of 48h exposures to copper and zinc on Atyaephyra desmarestii and Echinogammarus meridionalis were evaluated with a battery of biomarkers of oxidative stress and the determination of ingestion rates. The results showed different responses of biomarkers between species and each metal. Copper inhibited the enzymatic defence system of both species without signs of oxidative damage. Zinc induced the defence system in E. meriodionalis with no evidence of oxidative damage. However, in A. desmarestii exposed to zinc was observed oxidative damage. In addition, only zinc had significantly reduced the ingestion rate and just for E. meridionalis. The value of the integrated biomarkers response increased with concentration of both metals, which indicates that might be a valuable tool to interpretation of data as a whole, as different parameters have different weight according to type of exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of zinc oxide nanoparticles on nitrogen removal, microbial activity and microbial community of CANON process in a membrane bioreactor.

PubMed

Zhang, Xiaojing; Zhang, Nan; Fu, Haoqiang; Chen, Tao; Liu, Sa; Zheng, Shuhua; Zhang, Jie

2017-11-01

In this study, a membrane bioreactor (MBR) was adopted for completely autotrophic nitrogen removal over nitrite (CANON) process. Zinc oxide nanoparticles (ZnO NPs) was step-wise increased to analyze the influence on nitrogen removal, microbial activity and microbial communities. Finally ZnO NPs was removed to study its recovery capability. The bioactivities of ammonia-oxidizing bacteria (AOB), anaerobic ammonia-oxidizing bacteria (AAOB) and nitrite-oxidizing bacteria (NOB) were detected by batch experiments. Results showed that the ZnO NPs with low concentration (≤5mgL -1 ) was profitable for nitrogen removal while the high concentration performed inhibition, and it lowered the abundance of both AOB and NOB while enhanced that of AAOB. ZnO NPs with high concentration (≥10mgL -1 ) suppressed both AOB and AAOB, and long-term exposure within ZnO NPs led to microbial diversity decrease. The inhibition threshold of ZnO NPs on CANON process was 10mgL -1 , and the profitable concentration was 1mgL -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Cs promoted oxidation of Zn and CuZn surfaces: a combined experimental and theoretical study

NASA Astrophysics Data System (ADS)

Chaturvedi, Sanjay; Rodriguez, JoséA.; Hrbek, Jan

1997-07-01

The interaction of O 2 with Zn, {Cs}/{Zn} and {Cs}/{CuZn} surfaces was investigated using photoemission and ab initio self-consistent-field (SCF) calculations. On zinc films, the sticking probability of O 2 is extremely low (10 -3-10 -2), and O 2 exposures in the range of 10 3 to 10 4 langmuirs are necessary to produce a significant adsorption of oxygen and the transformation of metallic zinc into zinc oxide. The presence of sub monolayer coverages of cesium enhances the oxidation rate of zinc by 2-3 orders of magnitude. In the {Cs}/{Zn} system, the alkali atom donates electrons to zinc. This charge transfer facilitates the formation of Zn→O 2 dative bonds and breaking of the OO bond. For the coadsorption of Cs and O 2 on Zn(001), the larger the electron transfer from Zn into the O 2 (1 πg) orbitals, the bigger the adsorption energy of the molecule and the elongation of the OO bond. In general, cesium does not promote the oxidation of copper. In the {Cs}/{CuZn} system, copper withdraws electrons from zinc. The presence of copper in the {Cs}/{CuZn} system inhibits the oxidation of the Zn component compared with the {Cs}/{Zn} system by lowering the electron density on the Zn atoms. After exposing the {Cs}/{CuZn} system to O 2, zinc is oxidized at a rate that is larger than that found for clean CuZn surfaces and smaller than seen in {Cs}/{Zn} surfaces. Molecular hydrogen is found to have no effect on oxidized Cu, Zn and CuZn films. However, atomic hydrogen reduces ZnO to metallic zinc and CuO to Cu 2O. In the oxidized CuZn alloy, CuO is reduced first followed by the reduction of ZnO. A comparison of the behavior of O 2/Cs/Zn and H 2O/Cs/Zn systems shows that while O 2 causes severe oxidation of Cs promoted Zn surfaces, H 2O has little or no effect.

Developmental phytotoxicity of metal oxide nanoparticles to Arabidopsis thaliana.

PubMed

Lee, Chang Woo; Mahendra, Shaily; Zodrow, Katherine; Li, Dong; Tsai, Yu-Chang; Braam, Janet; Alvarez, Pedro J J

2010-03-01

Phytotoxicity is an important consideration to understand the potential environmental impacts of manufactured nanomaterials. Here, we report on the effects of four metal oxide nanoparticles, aluminum oxide (nAl(2)O(3)), silicon dioxide (nSiO(2)), magnetite (nFe(3)O(4)), and zinc oxide (nZnO), on the development of Arabidopsis thaliana (Mouse-ear cress). Three toxicity indicators (seed germination, root elongation, and number of leaves) were quantified following exposure to each nanoparticle at three concentrations: 400, 2,000, and 4,000 mg/L. Among these particles, nZnO was most phytotoxic, followed by nFe(3)O(4), nSiO(2), and nAl(2)O(3), which was not toxic. Consequently, nZnO was further studied to discern the importance of particle size and zinc dissolution as toxicity determinants. Soluble zinc concentrations in nanoparticle suspensions were 33-fold lower than the minimum inhibitory concentration of dissolved zinc salt (ZnCl(2)), indicating that zinc dissolution could not solely account for the observed toxicity. Inhibition of seed germination by ZnO depended on particle size, with nanoparticles exerting higher toxicity than larger (micron-sized) particles at equivalent concentrations. Overall, this study shows that direct exposure to nanoparticles significantly contributed to phytotoxicity and underscores the need for eco-responsible disposal of wastes and sludge containing metal oxide nanoparticles.

Roles of zinc and metallothionein-3 in oxidative stress-induced lysosomal dysfunction, cell death, and autophagy in neurons and astrocytes.

PubMed

Lee, Sook-Jeong; Koh, Jae-Young

2010-10-26

Zinc dyshomeostasis has been recognized as an important mechanism for cell death in acute brain injury. An increase in the level of free or histochemically reactive zinc in astrocytes and neurons is considered one of the major causes of death of these cells in ischemia and trauma. Although zinc dyshomeostasis can lead to cell death via diverse routes, the major pathway appears to involve oxidative stress.Recently, we found that a rise of zinc in autophagic vacuoles, including autolysosomes, is a prerequisite for lysosomal membrane permeabilization and cell death in cultured brain cells exposed to oxidative stress conditions. The source of zinc in this process is likely redox-sensitive zinc-binding proteins such as metallothioneins, which release zinc under oxidative conditions. Of the metallothioneins, metallothionein-3 is especially enriched in the central nervous system, but its physiologic role in this tissue is not well established. Like other metallothioneins, metallothionein-3 may function as metal detoxicant, but is also known to inhibit neurite outgrowth and, sometimes, promote neuronal death, likely by serving as a source of toxic zinc release. In addition, metallothionein-3 regulates lysosomal functions. In the absence of metallothionein-3, there are changes in lysosome-associated membrane protein-1 and -2, and reductions in certain lysosomal enzymes that result in decreased autophagic flux. This may have dual effects on cell survival. In acute oxidative injury, zinc dyshomeostasis and lysosomal membrane permeabilization are diminished in metallothionein-3 null cells, resulting in less cell death. But over the longer term, diminished lysosomal function may lead to the accumulation of abnormal proteins and cause cytotoxicity.The roles of zinc and metallothionein-3 in autophagy and/or lysosomal function have just begun to be investigated. In light of evidence that autophagy and lysosomes may play significant roles in the pathogenesis of various neurological diseases, further insight into the contribution of zinc dynamics and metallothionein-3 function may help provide ways to effectively regulate these processes in brain cells.

Zinc oxide nanoparticle suspensions and layer-by-layer coatings inhibit staphylococcal growth.

PubMed

McGuffie, Matthew J; Hong, Jin; Bahng, Joong Hwan; Glynos, Emmanouil; Green, Peter F; Kotov, Nicholas A; Younger, John G; VanEpps, J Scott

2016-01-01

Despite a decade of engineering and process improvements, bacterial infection remains the primary threat to implanted medical devices. Zinc oxide nanoparticles (ZnO-NPs) have demonstrated antimicrobial properties. Their microbial selectivity, stability, ease of production, and low cost make them attractive alternatives to silver NPs or antimicrobial peptides. Here we sought to (1) determine the relative efficacy of ZnO-NPs on planktonic growth of medically relevant pathogens; (2) establish the role of bacterial surface chemistry on ZnO-NP effectiveness; (3) evaluate NP shape as a factor in the dose-response; and (4) evaluate layer-by-layer (LBL) ZnO-NP surface coatings on biofilm growth. ZnO-NPs inhibited bacterial growth in a shape-dependent manner not previously seen or predicted. Pyramid shaped particles were the most effective and contrary to previous work, larger particles were more effective than smaller particles. Differential susceptibility of pathogens may be related to their surface hydrophobicity. LBL ZnO-NO coatings reduced staphylococcal biofilm burden by >95%. From the Clinical Editor: The use of medical implants is widespread. However, bacterial colonization remains a major concern. In this article, the authors investigated the use of zinc oxide nanoparticles (ZnO-NPs) to prevent bacterial infection. They showed in their experiments that ZnO-NPs significantly inhibited bacterial growth. This work may present a new alternative in using ZnO-NPs in medical devices. Copyright © 2015 Elsevier Inc. All rights reserved.

Differential Expression of Zinc Transporters in Prostate Epithelia of Racial Groups

DTIC Science & Technology

2010-09-01

mitochondria inhibits terminal oxidation, truncating the Krebs cycle , hence decreasing the ATP-based energy production and resulting in less growth...as a major component of prostatic fluid [7,10]. In addition, high Zn levels in the mitochondria inhibits terminal oxidation, truncat- ing the Krebs ...PCR (MJR/Bio-Rod – Twin Tower, PTC 200, Waltham, MA). The two cycles were programmed for 30 min at 50 C, then 95 C for 5 min (for cDNA step), and

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.

Core/shell structured Zn/ZnO nanoparticles synthesized by gaseous laser ablation with enhanced photocatalysis efficiency

NASA Astrophysics Data System (ADS)

Song, Lu; Wang, Yafei; Ma, Jing; Zhang, Qinghua; Shen, Zhijian

2018-06-01

Zinc oxide (ZnO) is a competitive candidate in semiconductor photocatalysts, only if the efficiency could be fully optimized especially by tailored nanostructures. Here we report a kind of core/shell structured Zn/ZnO nanoparticles with enhanced photocatalysis efficiency, which were synthesized by a highly-productive gaseous laser ablation method. The nanodroplets generated by laser ablation would be reduced to zinc in the protective atmosphere, and further be oxidized at surface to form a specific core/shell structured Zn/ZnO nanoparticles within seconds. Thanks to the formation of this Zn-ZnO Schottky junction, the photocatalysis degradation efficiency of such core/shell Zn/ZnO nanostructure is significantly improved owing to the enhanced visible light absorption and inhibited carrier recombination by introducing the metallic zinc.

Surface coverage and corrosion inhibition effect of Rosmarinus officinalis and zinc oxide on the electrochemical performance of low carbon steel in dilute acid solutions

NASA Astrophysics Data System (ADS)

Loto, Roland Tolulope

2018-03-01

Electrochemical analysis of the corrosion inhibition and surface protection properties of the combined admixture of Rosmarinus officinalis and zinc oxide on low carbon steel in 1 M HCl and H2SO4 solution was studied by potentiodynamic polarization, open circuit potential measurement, optical microscopy and ATR-FTIR spectroscopy. Results obtained confirmed the compound to be more effective in HCl solution, with optimal inhibition efficiencies of 93.26% in HCl and 87.7% in H2SO4 acid solutions with mixed type inhibition behavior in both acids. The compound shifts the corrosion potential values of the steel cathodically in HCl and anodically in H2SO4 signifying specific corrosion inhibition behavior without applied potential. Identified functional groups of alcohols, phenols, 1°, 2° amines, amides, carbonyls (general), esters, saturated aliphatic, carboxylic acids, ethers, aliphatic amines, alkenes, aromatics, alkyl halides and alkynes within the compound completely adsorbed onto the steel forming a protective covering. Thermodynamic calculations showed physisorption molecular interaction with the steel's surface according to Langmuir and Frumkin adsorption isotherms. Optical microscopy images of the inhibited and uninhibited steels contrast each other with steel specimens from HCl solution showing a better morphology.

A Zinc Morpholine Complex Prevents HCl/Ethanol-Induced Gastric Ulcers in a Rat Model

PubMed Central

Salama, Suzy M.; Gwaram, Nura Suleiman; AlRashdi, Ahmed S.; Khalifa, Shaden A. M.; Abdulla, Mahmood A.; Ali, Hapipah M.; El-Seedi, Hesham R.

2016-01-01

Zinc is a naturally occurring element with roles in wound healing and rescuing tissue integrity, particularly in the gastrointestinal system, where it can be detected in the mucosal and submucosal layers. Zinc chelates are known to have beneficial effects on the gastrointestinal mucosa and in cases of gastric ulcer. We synthesized complexes of zinc featuring a heterocyclic amine binding amino acids then investigated their ability to enhance the gastric self-repair. Zinc-morpholine complex, Zn(L)SCN, namely showed strong free-radical scavenging, promotion of the DNA and RNA polymerases reconstruction and suppression of cell damage. The complex’s mode of action is proposed to involve hydrogen bond formation via its bis(thiocyanato-k)zinc moiety. Zn(L)SCN complex had potent effects on gastric enzymatic activity both in vitro and in vivo. The complex disrupted the ulcerative process as demonstrated by changes in the intermediate metabolites of the oxidative pathway – specifically, reduction in the MDA levels and elevation of reduced glutathione together with an attenuation of oxidative DNA damage. Additionally, Zn(L)SCN restored the gastric mucosa, inhibited the production of pro-inflammatory cytokines (IL-6, TNF and the caspases), and preserved the gastric mucous balance. Zn(L)SCN thus exhibited anti-oxidative, anti-inflammatory and anti-apoptotic activities, all of which have cytoprotective effects on the gastric lining. PMID:27460157

Inhibiting Metal Oxide Atomic Layer Deposition: Beyond Zinc Oxide

DOE PAGES

Sampson, Matthew D.; Emery, Jonathan D.; Pellin, Michael J.; ...

2017-04-05

The atomic layer deposition (ALD) of several metal oxides is selectivity inhibited on alkanethiol self-assembled monolayers (SAMs) on Au and the eventual nucleation mechanism is investigated. The inhibition ability of the SAM is significantly improved by the in situ H 2-plasma pretreatment of the Au substrate prior to gas-phase deposition of a long-chain alkanethiol, 1-dodecanethiol (DDT). This more rigorous surface preparation inhibits even aggressive oxide ALD precursors, including trimethylaluminum and water, for at least 20 cycles. We study the effect that ALD precursor purge times, growth temperature, alkanethiol chain length, alkanethiol deposition time, and plasma treatment time have on Almore » 2O 3 ALD inhibition. This is the first example of Al 2O 3 ALD inhibition from a vapor-deposited SAM. Inhibition of Al 2O 3, ZnO, and MnO ALD processes are compared, revealing the versatility of this selective surface treatment. As a result, atomic force microscopy (AFM) and grazing incidence x-ray fluorescence (GIXRF) further reveals insight into the mechanism by which the well-defined surface chemistry of ALD may eventually be circumvented to allow metal oxide nucleation and growth on SAM-modified surfaces.« less

Inhibiting Metal Oxide Atomic Layer Deposition: Beyond Zinc Oxide

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

Sampson, Matthew D.; Emery, Jonathan D.; Pellin, Michael J.

The atomic layer deposition (ALD) of several metal oxides is selectivity inhibited on alkanethiol self-assembled monolayers (SAMs) on Au and the eventual nucleation mechanism is investigated. The inhibition ability of the SAM is significantly improved by the in situ H 2-plasma pretreatment of the Au substrate prior to gas-phase deposition of a long-chain alkanethiol, 1-dodecanethiol (DDT). This more rigorous surface preparation inhibits even aggressive oxide ALD precursors, including trimethylaluminum and water, for at least 20 cycles. We study the effect that ALD precursor purge times, growth temperature, alkanethiol chain length, alkanethiol deposition time, and plasma treatment time have on Almore » 2O 3 ALD inhibition. This is the first example of Al 2O 3 ALD inhibition from a vapor-deposited SAM. Inhibition of Al 2O 3, ZnO, and MnO ALD processes are compared, revealing the versatility of this selective surface treatment. As a result, atomic force microscopy (AFM) and grazing incidence x-ray fluorescence (GIXRF) further reveals insight into the mechanism by which the well-defined surface chemistry of ALD may eventually be circumvented to allow metal oxide nucleation and growth on SAM-modified surfaces.« less

Zinc and Copper Metabolism and Risk of Autism: a reply to Sayehmiri et al.

PubMed

Fluegge Ba, Keith

2017-01-01

Sayehmiri et al. recently conducted a meta-analysis to explore the relationship between zinc and copper metabolism and autism spectrum disorders (ASD). Recent reports have elucidated a full behavioral profile of mice exposed to prenatal zinc deficiency and documented a phenotype similar to that found in autism spectrum disorders (ASD). These studies suggest that significant alterations in Zn metabolism may be an important nutritional component in the development of ASD. The idea that prenatal zinc deficiency may be to blame is cursorily challenged. Epidemiological studies show that high-income countries with a low estimated prevalence of inadequate zinc intake report the highest prevalence of ASD. Consistent with other reports indicating a link between air pollution and ASD, it has recently been proposed that use of the herbicide, glyphosate, in agriculture may serve as an instrumental variable in predicting later neurodevelopmental impairment via emissions of the agricultural air pollutant, nitrous oxide (N2O). Work in anesthesiology has demonstrated the neurological effects from subanesthetic doses of N2O, including its inhibition of the alpha 7 nicotinic acetylcholine receptor (α7), a receptor coupled to both central nitric oxide (NO) metabolism and peripheral anti-inflammation. This correspondence explores how the aforementioned nutritional phenotypes found by Sayehmiri et al. in their systematic review may be a compensatory mechanism to counter the effects (namely, α7 inhibition) of air pollutant exposures occurring during the most critical stages of fetal development.

Zinc oxide tetrapods inhibit herpes simplex virus infection of cultured corneas

PubMed Central

Duggal, Neil; Jaishankar, Dinesh; Yadavalli, Tejabhiram; Hadigal, Satvik; Mishra, Yogendra Kumar; Adelung, Rainer

2017-01-01

Purpose Infection of the human cornea by herpes simplex virus type-1 (HSV-1) can cause significant vision loss. The purpose of this study was to develop an ex vivo model to visualize viral growth and spread in the cornea. The model was also used to analyze cytokine production and study the antiviral effects of zinc oxide tetrapods. Methods A β-galactosidase-expressing recombinant virus, HSV-1(KOS)tk12, was used to demonstrate the ability of the virus to enter and develop blue plaques on human corneal epithelial (HCE) cells and corneal tissues. Freshly obtained porcine corneas were cultured and then scratched before infection with HSV-1(KOS)tk12. The blue plaques on the corneas were imaged using a stereomicroscope. Western blot analysis for HSV-1 proteins was performed to verify HSV-1 infection of the cornea. Using the ex vivo model, zinc oxide tetrapods were tested for their anti-HSV-1 potential, and a cytokine profile was developed to assess the effects of the treatment. Results Cultured corneas and the use of β-galactosidase-expressing HSV-1(KOS)tk12 virus can provide an attractive ex vivo model to visualize and study HSV-1 entry and spread of the infection in tissues. We found that unlike cultured HCE cells, which demonstrated nearly 100% infectivity, HSV-1 infection of the cultured cornea was more restrictive and took longer to develop. We also found that the zinc oxide tetrapod–shaped nano- and microstructures inhibited HSV infection of the cultured cells, as well as the cultured corneas. The cytokine profile of the infected samples was consistent with previous studies of HSV-1 corneal infection. Conclusions The ability to visualize HSV-1 growth and spread in corneal tissues can provide new details about HSV-1 infection of the cornea and the efficacy of new cornea-specific antiviral drug candidates. The ex vivo model also demonstrates antiviral effects of zinc oxide tetrapods and adequately portrays the drug delivery issues that cornea-specific treatments face. PMID:28275313

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats.

PubMed

Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague-Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn(2+) and albumin levels (P<0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P<0.01). qBase(+) was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P<0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. Copyright © 2015 Elsevier Inc. All rights reserved.

Angiotensin II potentiates zinc-induced cortical neuronal death by acting on angiotensin II type 2 receptor.

PubMed

Park, Mi-Ha; Kim, Ha Na; Lim, Joon Seo; Ahn, Jae-Sung; Koh, Jae-Young

2013-12-01

The angiotensin system has several non-vascular functions in the central nervous system. For instance, inhibition of the brain angiotensin system results in a reduction in neuronal death following acute brain injury such as ischemia and intracerebral hemorrhage, even under conditions of constant blood pressure. Since endogenous zinc has been implicated as a key mediator of ischemic neuronal death, we investigated the possibility that the angiotensin system affects the outcome of zinc-triggered neuronal death in cortical cell cultures. Exposure of cortical cultures containing neurons and astrocytes to 300 μM zinc for 15 min induced submaximal death in both types of cells. Interestingly, addition of angiotensin II significantly enhanced the zinc-triggered neuronal death, while leaving astrocytic cell death relatively unchanged. Both type 1 and 2 angiotensin II receptors (AT1R and AT2R, respectively) were expressed in neurons as well as astrocytes. Zinc neurotoxicity was substantially attenuated by PD123319, a specific inhibitor of AT2R, and augmented by CGP42112, a selective activator of AT2R, indicating a critical role for this receptor subtype in the augmentation of neuronal cell death.Because zinc toxicity occurs largely through oxidative stress, the levels of superoxides in zinc-treated neurons were assessed by DCF fluorescence microscopy. Combined treatment with zinc and angiotensin II substantially increased the levels of superoxides in neurons compared to those induced by zinc alone. This increase in oxidative stress by angiotensin II was completely blocked by the addition of PD123319. Finally, since zinc-induced oxidative stress may be caused by induction and/or activation of NADPH oxidase, the activation status of Rac and the level of the NADPH oxidase subunit p67phox were measured. Angiotensin II markedly increased Rac activity and the levels of p67phox in zinc-treated neurons and astrocytes in a PD123319-dependent manner. The present study shows that the angiotensin system, especially that involving AT2R, may have an oxidative injury-potentiating effect via augmentation of the activity of NADPH oxidase. Hence, blockade of angiotensin signaling cascades in the brain may prove useful in protecting against the oxidative neuronal death that is likely to occur in acute brain injury.

Zinc deficiency induces vascular pro-inflammatory parameters associated with NF-kappaB and PPAR signaling.

PubMed

Shen, Huiyun; Oesterling, Elizabeth; Stromberg, Arnold; Toborek, Michal; MacDonald, Ruth; Hennig, Bernhard

2008-10-01

Marginal intake of dietary zinc can be associated with increased risk of cardiovascular diseases. In the current study we hypothesized that vascular dysfunction and associated inflammatory events are activated during a zinc deficient state. We tested this hypothesis using both vascular endothelial cells and mice lacking the functional LDL-receptor gene. Zinc deficiency increased oxidative stress and NF-kappaB DNA binding activity, and induced COX-2 and E-selectin gene expression, as well as monocyte adhesion in cultured endothelial cells. The NF-kappaB inhibitor CAPE significantly reduced the zinc deficiency-induced COX-2 expression, suggesting regulation through NF-kappaB signaling. PPAR can inhibit NF-kappaB signaling, and our previous data have shown that PPAR transactivation activity requires adequate zinc. Zinc deficiency down-regulated PPARalpha expression in cultured endothelial cells. Furthermore, the PPARgamma agonist rosiglitazone was unable to inhibit the adhesion of monocytes to endothelial cells during zinc deficiency, an event which could be reversed by zinc supplementation. Our in vivo data support the importance of PPAR dysregulation during zinc deficiency. For example, rosiglitazone induced inflammatory genes (e.g., MCP-1) only during zinc deficiency, and adequate zinc was required for rosiglitazone to down-regulate pro-inflammatory markers such as iNOS. In addition, rosiglitazone increased IkappaBalpha protein expression only in zinc adequate mice. Finally, plasma data from LDL-R-deficient mice suggest an overall pro-inflammatory environment during zinc deficiency and support the concept that zinc is required for proper anti-inflammatory or protective functions of PPAR. These studies suggest that zinc nutrition can markedly modulate mechanisms of the pathology of inflammatory diseases such as atherosclerosis.

Identification and partial characterization of a low affinity metal-binding site in the light chain of tetanus toxin.

PubMed

Wright, J F; Pernollet, M; Reboul, A; Aude, C; Colomb, M G

1992-05-05

Tetanus toxin was shown to contain a metal-binding site for zinc and copper. Equilibrium dialysis binding experiments using 65Zn indicated an association constant of 9-15 microM, with one zinc-binding site/toxin molecule. The zinc-binding site was localized to the toxin light chain as determined by binding of 65Zn to the light chain but not to the heavy chain after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transfer to Immobilon membranes. Copper was an efficient inhibitor of 65Zn binding to tetanus toxin and caused two peptide bond cleavages in the toxin light chain in the presence of ascorbate. These metal-catalyzed oxidative cleavages were inhibited by the presence of zinc. Partial characterization of metal-catalyzed oxidative modifications of a peptide based on a putative metal-binding site (HELIH) in the toxin light chain was used to map the metal-binding site in the protein.

Characterizing the inhibitory action of zinc oxide nanoparticles on allergic-type mast cell activation.

PubMed

Feltis, B N; Elbaz, A; Wright, P F A; Mackay, G A; Turney, T W; Lopata, A L

2015-08-01

The development of nanoparticles (NPs) for commercial products is undergoing a dramatic expansion. Many sunscreens and cosmetics now use zinc oxide (ZnO) or titania (TiO2) NPs, which are effective ultraviolet (UV) filters. Zinc oxide topical creams are also used in mild anti-inflammatory treatments. In this study we evaluated the effect of size and dispersion state of ZnO and TiO2 NPs, compared to "bulk" ZnO, on mast cell degranulation and viability. ZnO and TiO2 NPs were characterized using dynamic light scattering and disc centrifugation. Rat basophilic leukaemia (RBL-2H3) cells and primary mouse bone marrow-derived mast cells (BMMCs) were exposed to ZnO and TiO2 NPs of different sizes (25-200 nm) and surface coatings at concentrations from 1 to 200 μg/mL. The effect of NPs on immunoglobulin E (IgE)-dependent mast cell degranulation was assessed by measuring release of both β-hexosaminidase and histamine via colorimetric and ELISA assays. The intracellular level of Zn(2+) and Ca(2+) ions were measured using zinquin ethyl ester and Fluo-4 AM fluorescence probes, respectively. Cellular viability was determined using the soluble tetrazolium-based MTS colorimetric assay. Exposure of RBL-2H3 and primary mouse BMMC to ZnO NPs markedly inhibited both histamine and β-hexosaminidase release. This effect was both particle size and dispersion dependent. In contrast, TiO2 NPs did not inhibit the allergic response. These effects were independent of cytotoxicity, which was observed only at high concentrations of ZnO NPs, and was not observed for TiO2 NPs. The inhibitory effects of ZnO NPs on mast cells were inversely proportional to particle size and dispersion status, and thus these NPs may have greater potential than "bulk" zinc in the inhibition of allergic responses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multiple Mechanisms of Zinc-Mediated Inhibition for the Apoptotic Caspases-3, -6, -7, and -8.

PubMed

Eron, Scott J; MacPherson, Derek J; Dagbay, Kevin B; Hardy, Jeanne A

2018-05-18

Zinc is emerging as a widely used and important biological regulatory signal. Cellular zinc levels are tightly regulated by a complex array of zinc importers and exporters to control processes such as apoptotic cell death. While caspase inhibition by zinc has been reported previously, the reported inhibition constants were too weak to suggest a critical biological role for zinc-mediated inhibition. In this work, we have adopted a method of assessing available zinc. This allowed assessment of accurate inhibition constants for apoptotic caspases, caspase-3, -6, -7, and -8. Each of these caspases are inhibited by zinc at intracellular levels but with widely differing inhibition constants and different zinc binding stoichiometries. Caspase-3, -6, and -8 appear to be constitutively inhibited by typical zinc levels, and this inhibition must be lifted to allow activation. The inhibition constant for caspase-7 (76 nM) is much weaker than for the other apoptotic caspases (2.6-6.9 nM) suggesting that caspase-7 is not inactivated by normal zinc concentrations but can be inhibited under conditions of zinc stress. Caspase-3, -7, and -8 were found to bind three, one, and two zincs, respectively. In each of these caspases, zinc was present in the active site, in contrast to caspase-6, which binds one zinc allosterically. The most notable new mechanism to emerge from this work is for zinc-mediated inhibition of caspase-8. Zinc binds caspase-8 directly at the active site and at a second site. Zinc binding inhibits formation of the caspase-8 dimer, the activated form of the enzyme. Together these findings suggest that zinc plays a critical role in regulation of apoptosis by direct inactivation of caspases, in a manner that is unique for each caspase.

Zinc and magnesium ions synergistically inhibit superoxide generation by cultured human neutrophils--a promising candidate formulation for amnioinfusion fluid.

PubMed

Uchida, Toshiyuki; Itoh, Hiroaki; Nakamura, Yuki; Kobayashi, Yukiko; Hirai, Kyuya; Suzuki, Kazunao; Sugihara, Kazuhiro; Kanayama, Naohiro; Hiramatsu, Mitsuo

2010-06-01

Oligohydramnios is often caused by the premature rupturing of membranes and subsequent intrauterine infections, such as chorioamnionitis, in which event oxidative stress is hypothesized to be closely associated with the damage to the fetal organs. The clinical efficiency of amnioinfusion using warmed saline in cases of premature rupture of membranes is still controversial, especially concerning the prognosis for the fetus. In the present study, we found that human amniotic fluid per se suppresses the release of superoxide from cultured human neutrophils, suggesting an acute or chronic shortage of amniotic fluid in cases of premature rupture of membranes can affect the shielding of intrauterine organs from oxidative stress. The aim of this study was to propose a formula of zinc and magnesium ions in saline for amnioinfusion, by assessing antioxidative activities. A combination of 5 microM zinc and 5mM magnesium in saline synergistically inhibited superoxide production by cultured human neutrophils, equivalent to human amniotic fluid. The intraperitoneal administration of this formula significantly improved the survival rate in a rat model of peritonitis compared to the saline control (46.7% vs. 10%). The combination of these metals with saline may thus be a promising formula for an amnioinfusion fluid with the capacity to protect fetal organs from oxidative stress. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Redox-dependent changes in RsrA, an anti-sigma factor in Streptomyces coelicolor: zinc release and disulfide bond formation.

PubMed

Bae, Jae-Bum; Park, Joo-Hong; Hahn, Mi-Young; Kim, Min-Sik; Roe, Jung-Hye

2004-01-09

sigmaR is a sigma factor for transcribing genes to defend cells against oxidative stresses in the antibiotic-producing bacterium Streptomyces coelicolor. The availability of sigmaR is regulated by RsrA, an anti-sigma factor, whose sigmaR-binding activity is regulated by redox changes in the environment, via thiol-disulfide exchange. We found that reduced RsrA contains zinc in a stoichiometric amount, whereas oxidized form has very little: 1 mol of zinc per mol of RsrA was released upon oxidation as monitored by a chromogenic Zn-chelator, 4-(2-pyridylazo)-resorcinol (PAR). Measurement of zinc bound in several RsrA mutants of various cysteine and histidine substitutions suggested that C3, H7, C41, and C44 serve as zinc-binding sites. The zinc-binding and sigmaR-binding activities of mutant proteins did not coincide, suggesting that zinc might not be absolutely required for the anti-sigma activity of RsrA. Zn-free apo-RsrA bound sigmaR and inhibited sigmaR-dependent transcription in vitro. Compared with Zn-RsrA, the anti-transcription activity of apo-RsrA was about threefold lower and its sigmaR-binding affinity decreased by about ninefold when measured by surface plasmon resonance analysis. Apo-RsrA was more sensitive to protease, suggesting that zinc allows RsrA to maintain a more compact structure, optimized for binding sigmaR. The cysteine pairs that form disulfide bonds were determined by MALDI-TOF mass spectrometry, revealing formation of the critical disulfide bond between C11 and one of the essential cysteine residues C41 or 44, most likely C44. An improved model for the mechanism of redox-modulation of RsrA was presented.

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). Copyright © 2014 Elsevier B.V. All rights reserved.

Inhibition effect of zinc in wastewater on the N2O emission from coastal loam soils.

PubMed

Huang, Yan; Ou, Danyun; Chen, Shunyang; Chen, Bin; Liu, Wenhua; Bai, Renao; Chen, Guangcheng

2017-03-15

The effects of zinc (Zn) on nitrous oxide (N 2 O) fluxes from coastal loam soil and the abundances of soil nitrifier and denitrifier were studied in a tidal microcosm receiving livestock wastewater with different Zn levels. Soil N 2 O emission significantly increased due to discharge of wastewater rich in ammonia (NH 4 + -N) while the continuous measurements of gas flux showed a durative reduction in N 2 O flux by high Zn input (40mgL -1 ) during the low tide period. Soil inorganic nitrogen concentrations increased at the end of the experiment and even more soil NH 4 + -N was measured in the high-Zn-level treatment, indicating an inhibition of ammonia oxidation by Zn input. Quantitative PCR of soil amoA, narG and nirK genes encoding ammonia monooxygenase, nitrate reductase and nitrite reductase, respectively, showed that the microbial abundances involved in these metabolisms were neither affected by wastewater discharge nor Zn contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-05-01

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

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparative evaluation of antimicrobial efficacy of various root canal filling materials along with aloevera used in primary teeth: a microbiological study.

PubMed

Kriplani, R; Thosar, N; Baliga, M S; Kulkarni, P; Shah, N; Yeluri, R

2013-01-01

this study was conducted to evaluate the antimicrobial effectiveness of 6 root canal filling materials and a negative control agent against 18 strains of bacteria isolated from infected root canals of primary molar teeth using agar diffusion assay. Aloevera with sterile water Zinc oxide and Eugenol, Zinc oxide-Eugenol with aloevera, Calcium hydroxide and sterile water, Calcium hydroxide with sterile water and aloevera, Calcium hydroxide and Iodoform (Metapex) and Vaseline (Control). MIC and MBC of aloevera was calculated. All materials except Vaseline showed varied antimicrobial activity against the test bacterias. The zones of inhibition were ranked into 4 inhibition categories based on the proportional distribution of the data. All the 18 bacterial isolates were classified under 2 groups based on Gram positive and Gram negative aerobes. Statistical analysis was carried out to compare the antimicrobial effectiveness between materials tested with each of the bacterial groupings. Aloevera + Sterile Water was found to have superior antimicrobial activity against most of the microorganisms followed by ZOE + Aloevera, calcium hydroxide + Aloevera, ZOE, calcium hydroxide, Metapex in the descending order and Vaseline showed no inhibition.

Edaravone protected PC12 cells against MPP(+)-cytoxicity via inhibiting oxidative stress and up-regulating heme oxygenase-1 expression.

PubMed

Cheng, Baohua; Guo, Yunliang; Li, Chuangang; Ji, Bingyuan; Pan, Yanyou; Chen, Jing; Bai, Bo

2014-08-15

Oxidative stress is involved in the pathogenesis of Parkinson's disease (PD). Edaravone has been shown to have a neuroprotective effect. In the present work, we investigated the effect of edaravone on 1-methyl-4-phenylpyridinium (MPP(+))-treated PC12 cells. Edaravone inhibited the decrease of cell viability and apoptosis induced by MPP(+) in PC12 cells. In addition, edaravone alleviated intracellular reactive oxygen species (ROS) production. MPP(+) induced heme oxygenase-1 (HO-1) expression, which was further enhanced by edaravone. The inhibitor of HO-1 zinc protoporphyrin-IX attenuated the neuroprotection of edaravone. So edaravone protected PC12 cells against MPP(+)-cytoxicity via inhibiting oxidative stress and up-regulating HO-1 expression. The data showed that edaravone was neuroprotective and could be potentially therapeutics for PD in future. Copyright © 2014 Elsevier B.V. All rights reserved.

Arsenite-induced ROS/RNS generation causes zinc loss and inhibits the activity of poly(ADP-ribose) polymerase-1.

PubMed

Wang, Feng; Zhou, Xixi; Liu, Wenlan; Sun, Xi; Chen, Chen; Hudson, Laurie G; Jian Liu, Ke

2013-08-01

Arsenic enhances the genotoxicity of other carcinogenic agents such as ultraviolet radiation and benzo[a]pyrene. Recent reports suggest that inhibition of DNA repair is an important aspect of arsenic cocarcinogenesis, and DNA repair proteins such as poly(ADP ribose) polymerase (PARP)-1 are direct molecular targets of arsenic. Although arsenic has been shown to generate reactive oxygen/nitrogen species (ROS/RNS), little is known about the role of arsenic-induced ROS/RNS in the mechanism underlying arsenic inhibition of DNA repair. We report herein that arsenite-generated ROS/RNS inhibits PARP-1 activity in cells. Cellular exposure to arsenite, as well as hydrogen peroxide and NONOate (nitric oxide donor), decreased PARP-1 zinc content, enzymatic activity, and PARP-1 DNA binding. Furthermore, the effects of arsenite on PARP-1 activity, DNA binding, and zinc content were partially reversed by the antioxidant ascorbic acid, catalase, and the NOS inhibitor, aminoguanidine. Most importantly, arsenite incubation with purified PARP-1 protein in vitro did not alter PARP-1 activity or DNA-binding ability, whereas hydrogen peroxide or NONOate retained PARP-1 inhibitory activity. These results strongly suggest that cellular generation of ROS/RNS plays an important role in arsenite inhibition of PARP-1 activity, leading to the loss of PARP-1 DNA-binding ability and enzymatic activity. Copyright © 2013 Elsevier Inc. All rights reserved.

Enhancement of antibacterial activity in nanofillers incorporated PSF/PVP membranes

NASA Astrophysics Data System (ADS)

Pramila, P.; Gopalakrishnan, N.

2018-04-01

An attempt has been made to investigate the nanofillers incorporated polysulfone (PSF) and polyvinylpyrrolidone (PVP) polymer membranes prepared by phase inversion method. Initially, the nanofillers, viz, Zinc Oxide (ZnO) nanoparticle, Graphene Oxide-Zinc Oxide (GO-ZnO) nanocomposite were synthesized and then directly incorporated into PSF/PVP blend during the preparation of membranes. The prepared membranes have been subjected to FE-SEM, AFM, BET, contact angle, tensile test and anti-bacterial studies. Significant membrane morphologies and nanoporous properties have been observed by FE-SEM and BET, respectively. It has been observed that hydrophilicity, mechanical strength and water permeability of the ZnO and GO-ZnO incorporated membranes were enhanced than bare membrane. Antibacterial activity was assessed by measuring the inhibition zones formed around the membrane by disc-diffusion method using Escherichia coli (gram-negative) as a model bacterium. Again, it has been observed that nanofillers incorporated membrane exhibits high antibacterial performance compared to bare membrane.

21 CFR 582.80 - Trace minerals added to animal feeds.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... Manganese phosphate (dibasic). Manganese sulfate. Manganous oxide. Zinc Zinc acetate. Zinc carbonate. Zinc chloride. Zinc oxide. Zinc sulfate. ... Cobalt Cobalt acetate. Cobalt carbonate. Cobalt chloride. Cobalt oxide. Cobalt sulfate. Copper Copper...

21 CFR 582.80 - Trace minerals added to animal feeds.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... Manganese phosphate (dibasic). Manganese sulfate. Manganous oxide. Zinc Zinc acetate. Zinc carbonate. Zinc chloride. Zinc oxide. Zinc sulfate. ... Cobalt Cobalt acetate. Cobalt carbonate. Cobalt chloride. Cobalt oxide. Cobalt sulfate. Copper Copper...

Selective oxidation of dual phase steel after annealing at different dew points

NASA Astrophysics Data System (ADS)

Lins, Vanessa de Freitas Cunha; Madeira, Laureanny; Vilela, Jose Mario Carneiro; Andrade, Margareth Spangler; Buono, Vicente Tadeu Lopes; Guimarães, Juliana Porto; Alvarenga, Evandro de Azevedo

2011-04-01

Hot galvanized steels have been extensively used in the automotive industry. Selective oxidation on the steel surface affects the wettability of zinc on steel and the grain orientation of inhibition layer (Fe-Al-Zn alloy) and reduces the iron diffusion to the zinc layer. The aim of this work is to identify and quantify selective oxidation on the surface of a dual phase steel, and an experimental steel with a lower content of manganese, annealed at different dew points. The techniques employed were atomic force microscopy, X-ray photoelectron spectroscopy, and glow discharge optical emission spectroscopy. External selective oxidation was observed for phosphorus on steel surface annealed at 0 °C dp, and for manganese, silicon, and aluminum at a lower dew point. The concentration of manganese was higher on the dual phase steel surface than on the surface of the experimental steel. The concentration of molybdenum on the surface of both steels increased as the depth increased.

Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

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

Aslam, I., E-mail: ia31@msstate.edu

2016-10-15

Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens in the interface region (~ 100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM), and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~ 20 nm was present on the surface of the substrate whilemore » no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~ 100 nm. Possible mechanisms for the growth of the inhibition layer were discussed. - Highlights: •Site-specific examinations were performed on the Zn/steel interface. •Continuous external MnO oxides (20 nm) were observed at the interface. •No Si oxides were observed at the interface. •Internal oxide particles were distributed in the subsurface. •A continuous inhibition layer grew on top of the external oxides.« less

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.

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.

Reactive Oxygen Species Mediated Bacterial Biofilm Inhibition via Zinc Oxide Nanoparticles and Their Statistical Determination

PubMed Central

Dwivedi, Sourabh; Wahab, Rizwan; Khan, Farheen; Mishra, Yogendra K.; Musarrat, Javed; Al-Khedhairy, Abdulaziz A.

2014-01-01

The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼10–15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods. PMID:25402188

Reactive oxygen species mediated bacterial biofilm inhibition via zinc oxide nanoparticles and their statistical determination.

PubMed

Dwivedi, Sourabh; Wahab, Rizwan; Khan, Farheen; Mishra, Yogendra K; Musarrat, Javed; Al-Khedhairy, Abdulaziz A

2014-01-01

The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼ 10-15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods.

Selective Sensitization of Zinc Finger Protein Oxidation by Reactive Oxygen Species through Arsenic Binding*

PubMed Central

Zhou, Xixi; Cooper, Karen L.; Sun, Xi; Liu, Ke J.; Hudson, Laurie G.

2015-01-01

Cysteine oxidation induced by reactive oxygen species (ROS) on redox-sensitive targets such as zinc finger proteins plays a critical role in redox signaling and subsequent biological outcomes. We found that arsenic exposure led to oxidation of certain zinc finger proteins based on arsenic interaction with zinc finger motifs. Analysis of zinc finger proteins isolated from arsenic-exposed cells and zinc finger peptides by mass spectrometry demonstrated preferential oxidation of C3H1 and C4 zinc finger configurations. C2H2 zinc finger proteins that do not bind arsenic were not oxidized by arsenic-generated ROS in the cellular environment. The findings suggest that selectivity in arsenic binding to zinc fingers with three or more cysteines defines the target proteins for oxidation by ROS. This represents a novel mechanism of selective protein oxidation and demonstrates how an environmental factor may sensitize certain target proteins for oxidation, thus altering the oxidation profile and redox regulation. PMID:26063799

Effect of glycerol and zinc oxide addition on antibacterial activity of biodegradable bioplastics from chitosan-kepok banana peel starch

NASA Astrophysics Data System (ADS)

Agustin, Y. E.; Padmawijaya, K. S.

2017-07-01

Bioplastic is a biopolymer plastic that can be degraded easily by microorganisms so it can be used as alternative replaced commercial plastic. This research aims to study the effects of additive (glycerol and zinc oxide) addition in the characteristic of antimicrobial activity and biodegradability bioplastic from chitosan and Kepok banana peel starch. In this research, bioplastics were synthesized by chitosan as the backbone and antimicrobial, Kepok banana peel starch as filler, glycerol as plasticizer, also ZnO as an amplifier. Bioplastics were characterized their antimicrobial activity using agar diffusion method (zone inhibition assay) and biodegradability test using microbe (EM4). The result showed the optimum composition of bioplastic is kitosan 4 - 30% starch - 5 mL glycerol - 5% ZnO gives the good antimicrobial activity towards gram positive and gram negative bacteria, and this bioplastic will be degraded within an hour and 12 min. Thus, this bioplastics may have potential to be use for food packaging by having biodegradable properties and also inhibit bacterial growth.

Effects of zinc oxide and titanium dioxide nanoparticles on green algae under visible, UVA, and UVB irradiations: no evidence of enhanced algal toxicity under UV pre-irradiation.

PubMed

Lee, Woo-Mi; An, Youn-Joo

2013-04-01

Some metal oxide nanoparticles are photoreactive, thus raising concerns regarding phototoxicity. This study evaluated ecotoxic effects of zinc oxide nanoparticles and titanium dioxide nanoparticles to the green algae Pseudokirchneriella subcapitata under visible, UVA, and UVB irradiation conditions. The nanoparticles were prepared in algal test medium, and the test units were pre-irradiated by UV light in a photoreactor. Algal assays were also conducted with visible, UVA or UVB lights only without nanoparticles. Algal growth was found to be inhibited as the nanoparticle concentration increased, and ZnO NPs caused destabilization of the cell membranes. We also noted that the inhibitory effects on the growth of algae were not enhanced under UV pre-irradiation conditions. This phenomenon was attributed to the photocatalytic activities of ZnO NPs and TiO2 NPs in both the visible and UV regions. The toxicity of ZnO NPs was almost entirely the consequence of the dissolved free zinc ions. This study provides us with an improved understanding of toxicity of photoreactive nanoparticles as related to the effects of visible and UV lights. Copyright © 2012 Elsevier Ltd. All rights reserved.

A comprehensive review of the role of zinc in normal prostate function and metabolism; and its implications in prostate cancer☆

PubMed Central

Costello, Leslie C.; Franklin, Renty B.

2016-01-01

The human prostate gland contains extremely high zinc levels; which is due to the specialized zinc-accumulating acinar epithelial of the peripheral zone. These cells evolved for their unique capability to produce and secrete extremely levels of citrate, which is achieved by the high cellular zinc level effects on the cell metabolism. This review highlights the specific functional and metabolic alterations that result from the accumulation of the high zinc levels, especially its effects on mitochondrial citrate metabolism and terminal oxidation. The implications of zinc in the development and progression of prostate cancer are described, which is the most consistent hallmark characteristic of prostate cancer. The requirement for decreased zinc resulting from down regulation of ZIP1 to prevent zinc cytotoxicity in the malignant cells is described as an essential early event in prostate oncogenesis. This provides the basis for the concept that an agent (such as the zinc ionophore, clioquinol) that facilitates zinc uptake and accumulation in ZIP1-deficient prostate tumors cells will markedly inhibit tumor growth. In the current absence of an efficacious chemotherapy for advanced prostate cancer, and for prevention of early development of malignancy; a zinc treatment regimen is a plausible approach that should be pursued. PMID:27132038

Analyzing the revolution of anaerobic ammonium oxidation (anammox) performance and sludge characteristics under zinc inhibition.

PubMed

Zhang, Qian-Qian; Zhang, Zheng-Zhe; Guo, Qiong; Wang, Jiao-Jiao; Wang, Hui-Zhong; Jin, Ren-Cun

2015-04-01

In the present study, the short- and long-term effects of Zn(II) on the anaerobic ammonium oxidation (anammox) performance and sludge characteristics were evaluated. The anammox activity decreased with increasing Zn(II) concentration and pre-exposure time in short-term tests. The half maximal inhibitory concentration (IC50) of Zn(II) was found to be 25.0 mg L(-1). The 24 and 48-h pre-exposure time was a restricted factor impacting the anammox activity, and washing the inhibited sludge with buffer solution only worked under 0 and 24-h pre-exposure time. The anammox sludge could tolerate 5 mg L(-1) Zn(II) but was suppressed at 8 mg L(-1). The inhibited performance could be remitted, as the combination strategies were applied, and after the short term of recovery period, the inhibited sludge characteristics were remitted to the normal.

Zinc protoporphyrin inhibition of lipopolysaccharide-, lipoteichoic acid-, and peptidoglycan-induced nitric oxide production through stimulating iNOS protein ubiquitination.

PubMed

Chow, Jyh-Ming; Lin, Hui-Yi; Shen, Shing-Chuan; Wu, Ming-Shun; Lin, Cheng-Wei; Chiu, Wen-Ta; Lin, Chien-Huang; Chen, Yen-Chou

2009-06-15

In the present study, zinc protoporphyrin (ZnPP), but not ferric protoporphyrin (FePP), tin protoporphyrin (SnPP), or zinc chloride (ZnCl(2)), at the doses of 0.5, 1, and 2 microM, dose-dependently inhibited lipopolysaccharide- (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN)-induced inducible nitric oxide (iNOS) and nitric oxide (NO) production with an increase in heme oxygenase 1 (HO-1) protein in RAW264.7 macrophages in a serum-free condition. NO inhibition and HO-1 induction by ZnPP were blocked by the separate addition of fetal bovine serum (FBS) and bovine serum albumin (BSA). A decrease in the iNOS/NO ratio and an increase in HO-1 protein by ZnPP were identified in three different conditions including ZnPP pretreatment, ZnPP co-treatment, and ZnPP post-treatment with LPS and LTA. Activation of c-Jun N-terminal kinases (JNKs) and extracellular regulated kinases (ERKs) were detected in LPS-, LTA-, and PGN-treated RAW264.7 cells, and iNOS/NO production was blocked by adding the JNK inhibitor, SP600125, but not the ERK inhibitor, PD98059. However, ZnPP addition potentiated ERK and JNK protein phosphorylation stimulated by LPS, LTA, and PGN. Increases in total protein ubiquitination and ubiquitinated iNOS proteins were detected in ZnPP-treated macrophages elicited by LPS according to Western and immunoprecipitation/Western blotting assays, respectively. The decrease in LPS-induced iNOS protein by ZnPP was reversed by adding the proteasome inhibitors MG132 and lactacystin. The reduction in HO-1 protein induced by ZnPP via transfection of HO-1 small interfering RNA did not affect the inhibitory effect of ZnPP against LPS-induced iNOS/NO production and protein ubiquitination induced by ZnPP in macrophages. Data of the present study provide the first evidence to support ZnPP effectively inhibiting inflammatory iNOS/NO production through activation of protein ubiquitination in a HO-1-independent manner in macrophages.

Zinc protoporphyrin inhibition of lipopolysaccharide-, lipoteichoic acid-, and peptidoglycan-induced nitric oxide production through stimulating iNOS protein ubiquitination

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

Chow, J.-M.; Lin, H.-Y.; Shen, S.-C.

2009-06-15

In the present study, zinc protoporphyrin (ZnPP), but not ferric protoporphyrin (FePP), tin protoporphyrin (SnPP), or zinc chloride (ZnCl{sub 2}), at the doses of 0.5, 1, and 2 {mu}M, dose-dependently inhibited lipopolysaccharide- (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN)-induced inducible nitric oxide (iNOS) and nitric oxide (NO) production with an increase in heme oxygenase 1 (HO-1) protein in RAW264.7 macrophages in a serum-free condition. NO inhibition and HO-1 induction by ZnPP were blocked by the separate addition of fetal bovine serum (FBS) and bovine serum albumin (BSA). A decrease in the iNOS/NO ratio and an increase in HO-1 protein bymore » ZnPP were identified in three different conditions including ZnPP pretreatment, ZnPP co-treatment, and ZnPP post-treatment with LPS and LTA. Activation of c-Jun N-terminal kinases (JNKs) and extracellular regulated kinases (ERKs) were detected in LPS-, LTA-, and PGN-treated RAW264.7 cells, and iNOS/NO production was blocked by adding the JNK inhibitor, SP600125, but not the ERK inhibitor, PD98059. However, ZnPP addition potentiated ERK and JNK protein phosphorylation stimulated by LPS, LTA, and PGN. Increases in total protein ubiquitination and ubiquitinated iNOS proteins were detected in ZnPP-treated macrophages elicited by LPS according to Western and immunoprecipitation/Western blotting assays, respectively. The decrease in LPS-induced iNOS protein by ZnPP was reversed by adding the proteasome inhibitors MG132 and lactacystin. The reduction in HO-1 protein induced by ZnPP via transfection of HO-1 small interfering RNA did not affect the inhibitory effect of ZnPP against LPS-induced iNOS/NO production and protein ubiquitination induced by ZnPP in macrophages. Data of the present study provide the first evidence to support ZnPP effectively inhibiting inflammatory iNOS/NO production through activation of protein ubiquitination in a HO-1-independent manner in macrophages.« less

Multi-year and short-term responses of soil ammonia-oxidizing prokaryotes to zinc bacitracin, monensin, and ivermectin, singly or in combination.

PubMed

Magda, Konopka; Hugh A L, Henry; Romain, Marti; Edward, Topp

2015-03-01

A field experiment was initiated whereby a series of replicated plots received annual applications of ivermectin, monensin, and zinc bacitracin, either singly or in a mixture. Pharmaceuticals were added at concentrations of 0.1 mg/kg soil or 10 mg/kg soil. The authors collected soil samples in 2013, before and after the fourth annual application of pharmaceuticals. In addition, a 30-d laboratory experiment was undertaken with the same soil and same pharmaceuticals, but at concentrations of 100 mg/kg soil. The impact of the pharmaceuticals on nitrification rates, on the abundance of ammonia-oxidizing bacteria (AOB), and on the abundance of ammonia-oxidizing archaea (AOA) was assessed. None of the pharmaceuticals at 0.1 mg/kg had any effect on nitrification. Referenced to control soil, nitrification was accelerated in soil exposed to 100 mg/kg zinc bacitracin or 10 mg/kg of the pharmaceutical mixture, but none of the treatments inhibited nitrification. Neither AOB abundance nor AOA abundance was affected by the pharmaceuticals at 0.1 mg/kg. At 10 mg/kg, monensin, zinc bacitracin, and a mixture of all 3 pharmaceuticals suppressed the abundance of AOB, and zinc bacitracin and the mixture increased AOA abundance. The decrease in AOB abundance and increase in AOA abundance when exposed to 10 mg/kg soil suggests that AOB are more sensitive to these chemicals and that AOA populations can expand to occupy the partially vacated niche. Published 2014 SETAC.

Distinct role of nitric oxide and peroxynitrite in mediating oligodendrocyte toxicity in culture and in experimental autoimmune encephalomyelitis.

PubMed

Li, S; Vana, A C; Ribeiro, R; Zhang, Y

2011-06-16

Nitric oxide has been implicated in the pathogenesis of multiple sclerosis. However, it is still unclear whether nitric oxide plays a protective role or is deleterious. We have previously shown that peroxynitrite, a reaction product of nitric oxide and superoxide, is toxic to mature oligodendrocytes (OLs). The toxicity is mediated by intracellular zinc release, phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), activation of 12-lipoxygenase (12-LOX) and the formation of reactive oxygen species (ROS). In this study, we found that the donors of nitric oxide, dipropylenetriamine NONOate (DPT NONOate) and diethylenetriamine NONOate (DETA NONOate), protected OLs from peroxynitrite or zinc-induced toxicity. The protective mechanisms appear to be attributable to their inhibition of peroxynitrite- or zinc-induced ERK1/2 phosphorylation and 12-LOX activation. In cultures of mature OLs exposed to lipopolysaccharide (LPS), induction of inducible nitric oxide synthase (iNOS) generated nitric oxide and rendered OLs resistant to peroxynitrite-induced toxicity. The protection was eliminated when 1400W, a specific inhibitor of iNOS, was co-applied with LPS. Using MOG35-55-induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, we found that nitrotyrosine immunoreactivity, an indicator of peroxynitrite formation, was increased in the spinal cord white matter, which correlated with the loss of mature OLs. Targeted gene deletion of the NADPH oxidase component gp91phox reduced clinical scores, the formation of nitrotyrosine and the loss of mature OLs. These results suggest that blocking the formation specifically of peroxynitrite, rather than nitric oxide, may be a protective strategy against oxidative stress induced toxicity to OLs. Published by Elsevier Ltd.

Fabrication of visible light-triggered photocatalytic materials from the coupling of n-type zinc oxide and p-type copper oxide

NASA Astrophysics Data System (ADS)

Gorospe, A. B.; Herrera, M. U.

2017-04-01

Coupling of copper oxide (CuO) and zinc oxide (ZnO) was done by chemical precipitation method. In this method, copper sulfate pentahydrate and zinc sulfate heptahydrate salt precursors were separately dissolved in distilled water; then were mixed together. The copper sulfate-zinc sulfate solution was then combined with a sodium hydroxide solution. The precipitates were collected and washed in distilled water and ethanol several times, then filtered and dried. The dried sample was grounded, and then undergone heat treatment. After heating, the sample was grounded again. Zinc oxide powder and copper oxide powder were also fabricated using chemical precipitation method. X-Ray Diffraction measurements of the coupled CuO/ZnO powder showed the presence of CuO and ZnO in the fabricated sample. Furthermore, other peaks shown by XRD were also identified corresponding to copper, copper (II) oxide, copper sulfate and zinc sulfate. Results of the photocatalytic activity investigation show that the sample exhibited superior photocatalytic degradation of methyl orange under visible light illumination compared to copper oxide powder and zinc oxide powder. This may be attributed to the lower energy gap at the copper oxide-zinc oxide interface, compared to zinc oxide, allowing visible light to trigger its photocatalytic activity.

Differential Regulation of Gene and Protein Expression by Zinc Oxide Nanoparticles in Hen’s Ovarian Granulosa Cells: Specific Roles of Nanoparticles

PubMed Central

Zhao, Yong; Li, Lan; Zhang, Peng-Fei; Shen, Wei; Liu, Jing; Yang, Fen-Fang; Liu, Hong-Bo; Hao, Zhi-Hui

2015-01-01

Annually, tons and tons of zinc oxide nanoparticles (ZnO NPs) are produced in the world. And they are applied in almost all aspects of our life. Their release from the products into environment may pose issue for human health. Although many studies have reported the adverse effects of ZnO NPs on organisms, little is known about the effects on female reproductive systems or the related mechanisms. Quantitative proteomics have not been applied although quantitative transcriptomics have been used in zinc oxide nanoparticles (ZnO NPs) research. Genes are very important players however proteins are the real actors in the biological systems. By using hen’s ovarian granulosa cells, it was found that ZnO-NP-5μg/ml and ZnSO4-10μg/ml treatments produced the same amount of intracellular Zn and resulted in similar cell growth inhibition. And NPs were found in the treated cells. However, ZnO-NP-5μg/ml specifically regulated the expression of genes and proteins compared with that in ZnSO4-10μg/ml treatment. For the first time, this investigation reports that intact NPs produce different impacts on the expression of genes and proteins involved in specific pathways compared to that by Zn2+. The findings enrich our knowledge for the molecular insights of zinc oxide nanoparticles effects on the female reproductive systems. This also may raise the health concern that ZnO NPs may adversely affect the female reproductive systems through regulation of specific signaling pathways. PMID:26460738

Differential Regulation of Gene and Protein Expression by Zinc Oxide Nanoparticles in Hen's Ovarian Granulosa Cells: Specific Roles of Nanoparticles.

PubMed

Zhao, Yong; Li, Lan; Zhang, Peng-Fei; Shen, Wei; Liu, Jing; Yang, Fen-Fang; Liu, Hong-Bo; Hao, Zhi-Hui

2015-01-01

Annually, tons and tons of zinc oxide nanoparticles (ZnO NPs) are produced in the world. And they are applied in almost all aspects of our life. Their release from the products into environment may pose issue for human health. Although many studies have reported the adverse effects of ZnO NPs on organisms, little is known about the effects on female reproductive systems or the related mechanisms. Quantitative proteomics have not been applied although quantitative transcriptomics have been used in zinc oxide nanoparticles (ZnO NPs) research. Genes are very important players however proteins are the real actors in the biological systems. By using hen's ovarian granulosa cells, it was found that ZnO-NP-5μg/ml and ZnSO4-10μg/ml treatments produced the same amount of intracellular Zn and resulted in similar cell growth inhibition. And NPs were found in the treated cells. However, ZnO-NP-5μg/ml specifically regulated the expression of genes and proteins compared with that in ZnSO4-10μg/ml treatment. For the first time, this investigation reports that intact NPs produce different impacts on the expression of genes and proteins involved in specific pathways compared to that by Zn2+. The findings enrich our knowledge for the molecular insights of zinc oxide nanoparticles effects on the female reproductive systems. This also may raise the health concern that ZnO NPs may adversely affect the female reproductive systems through regulation of specific signaling pathways.

Process for preparing zinc oxide-based sorbents

DOEpatents

Gangwal, Santosh Kumar [Cary, NC; Turk, Brian Scott [Durham, NC; Gupta, Raghubir Prasad [Durham, NC

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.

Effect of commercial metals (Al, Cu, carbon steel, and Zn) on the oxidation of soy-biodiesel

NASA Astrophysics Data System (ADS)

Díaz-Ballote, L.; Castillo-Atoche, A.; Maldonado, L.; Ruiz-Gómez, M. A.; Hernández, E.

2016-09-01

The effect of aluminum, copper, low carbon steel and zinc on the oxidation of biodiesel derived from soybean oil is studied using residual mass curves from thermogravimetry. Biodiesel is oxidized in the presence and absence of each metal in static conditions and exposed to ambient air. Oxidized biodiesel parameters are confirmed by viscosity measurements, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The results showed that the metals do not negatively influence the oxidative stability of biodiesel and it can even be considered that they slightly inhibit the oxidation process. This behavior was ascribed to a depletion of dissolved oxygen in biodiesel due to oxidation of the metal and the low solubility of oxygen at high temperature.

Zinc-mediated Allosteric Inhibition of Caspase-6*

PubMed Central

Velázquez-Delgado, Elih M.; Hardy, Jeanne A.

2012-01-01

Zinc and caspase-6 have independently been implicated in several neurodegenerative disorders. Depletion of zinc intracellularly leads to apoptosis by an unknown mechanism. Zinc inhibits cysteine proteases, including the apoptotic caspases, leading to the hypothesis that zinc-mediated inhibition of caspase-6 might contribute to its regulation in a neurodegenerative context. Using inductively coupled plasma optical emission spectroscopy, we observed that caspase-6 binds one zinc per monomer, under the same conditions where the zinc leads to complete loss of enzymatic activity. To understand the molecular details of zinc binding and inhibition, we performed an anomalous diffraction experiment above the zinc edge. The anomalous difference maps showed strong 5σ peaks, indicating the presence of one zinc/monomer bound at an exosite distal from the active site. Zinc was not observed bound to the active site. The zinc in the exosite was liganded by Lys-36, Glu-244, and His-287 with a water molecule serving as the fourth ligand, forming a distorted tetrahedral ligation sphere. This exosite appears to be unique to caspase-6, as the residues involved in zinc binding were not conserved across the caspase family. Our data suggest that binding of zinc at the exosite is the primary route of inhibition, potentially locking caspase-6 into the inactive helical conformation. PMID:22891250

Zinc and the modulation of redox homeostasis

PubMed Central

Oteiza, Patricia I.

2012-01-01

Zinc, a redox inactive metal, has been long viewed as a component of the antioxidant network, and growing evidence points to its involvement in redox-regulated signaling. These actions are exerted through several mechanisms based on the unique chemical and functional properties of zinc. Overall, zinc contributes to maintain the cell redox balance through different mechanisms including: i) the regulation of oxidant production and metal-induced oxidative damage; ii) the dynamic association of zinc with sulfur in protein cysteine clusters, from which the metal can be released by nitric oxide, peroxides, oxidized glutathione and other thiol oxidant species; iii) zinc-mediated induction of the zinc-binding protein metallothionein, which releases the metal under oxidative conditions and act per se scavenging oxidants; iv) the involvement of zinc in the regulation of glutathione metabolism and of the overall protein thiol redox status; and v) a direct or indirect regulation of redox signaling. Findings of oxidative stress, altered redox signaling, and associated cell/tissue disfunction in cell and animal models of zinc deficiency, stress the relevant role of zinc in the preservation of cell redox homeostasis. However, while the participation of zinc in antioxidant protection, redox sensing, and redox-regulated signaling is accepted, the involved molecules, targets and mechanisms are still partially known and the subject of active research. PMID:22960578

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.

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.

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

PubMed

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

2009-08-01

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

Incorporation of zinc oxide nanoparticles into chitosan-collagen 3D porous scaffolds: Effect on morphology, mechanical properties and cytocompatibility of 3D porous scaffolds.

PubMed

Ullah, Saleem; Zainol, Ismail; Idrus, Ruszymah Hj

2017-11-01

The zinc oxide nanoparticles (particles size <50nm) incorporated into chitosan-collagen 3D porous scaffolds and investigated the effect of zinc oxide nanoparticles incorporation on microstructure, mechanical properties, biodegradation and cytocompatibility of 3D porous scaffolds. The 0.5%, 1.0%, 2.0% and 4.0% zinc oxide nanoparticles chitosan-collagen 3D porous scaffolds were fabricated via freeze-drying technique. The zinc oxide nanoparticles incorporation effects consisting in chitosan-collagen 3D porous scaffolds were investigated by mechanical and swelling tests, and effect on the morphology of scaffolds examined microscopically. The biodegradation and cytocompatibility tests were used to investigate the effects of zinc oxide nanoparticles incorporation on the ability of scaffolds to use for tissue engineering application. The mean pore size and swelling ratio of scaffolds were decreased upon incorporation of zinc oxide nanoparticles however, the porosity, tensile modulus and biodegradation rate were increased upon incorporation of zinc oxide nanoparticles. In vitro culture of human fibroblasts and keratinocytes showed that the zinc oxide nanoparticles facilitated cell adhesion, proliferation and infiltration of chitosan-collagen 3D porous scaffolds. It was found that the zinc oxide nanoparticles incorporation enhanced porosity, tensile modulus and cytocompatibility of chitosan-collagen 3D porous scaffolds. Copyright © 2017 Elsevier B.V. All rights reserved.

Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate–Glutathione Cycle

PubMed Central

Tripathi, Durgesh K.; Mishra, Rohit K.; Singh, Swati; Singh, Samiksha; Vishwakarma, Kanchan; Sharma, Shivesh; Singh, Vijay P.; Singh, Prashant K.; Prasad, Sheo M.; Dubey, Nawal K.; Pandey, Avinash C.; Sahi, Shivendra; Chauhan, Devendra K.

2017-01-01

The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate–glutatione cycle (AsA–GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA–GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA–GSH cycle. PMID:28220127

Salmonella Utilizes Zinc To Subvert Antimicrobial Host Defense of Macrophages via Modulation of NF-κB Signaling

PubMed Central

Wu, Aimin; Haschka, David; Heeke, Simon; Dichtl, Stefanie; Petzer, Verena; Seifert, Markus; Hilbe, Richard; Sopper, Sieghart; Talasz, Heribert; Bumann, Dirk; Lass-Flörl, Cornelia; Theurl, Igor; Zhang, Keying

2017-01-01

ABSTRACT Zinc sequestration by macrophages is considered a crucial host defense strategy against infection by the intracellular bacterium Salmonella enterica serovar Typhimurium. However, the underlying mechanisms remain elusive. In this study, we found that zinc favors pathogen survival within macrophages. Salmonella-hosting macrophages contained higher free zinc levels than did uninfected macrophages and cells that successfully eliminated bacteria, which was paralleled by the impaired production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in bacterium-harboring cells. A profound, zinc-mediated inhibition of NF-κB p65 transcriptional activity affecting the expression of the ROS- and RNS-forming enzymes phos47 and inducible nitric oxide synthase (iNOS) provided a mechanistic explanation for this phenomenon. Macrophages responded to infection by enhancing the expression of zinc-scavenging metallothioneins 1 and 2, whose genetic deletion caused increased free zinc levels, reduced ROS and RNS production, and increased the survival of Salmonella. Our data suggest that Salmonella invasion of macrophages results in a bacterium-driven increase in the intracellular zinc level, which weakens antimicrobial defense and the ability of macrophages to eradicate the pathogen. Thus, limitation of cytoplasmic zinc levels may help to control infection by intracellular bacteria. PMID:28874447

Effect of zinc and benzalkonium chloride on Nitrosomonas communis and potential nitrification in soil.

PubMed

Frühling, W; Rönnpagel, K; Ahlf, W

2001-10-01

A bacterial contact assay is described which uses a chemoautotrophic microorganism, Nitrosomonas communis (strain Nm2) to evaluate the biological effect of contaminated soils. The effects of two toxicants on the ammonium oxidation activity of the autochthonous microbial population in the soil are compared with inhibition of the same biological response in the new monospecies bioassay. Experiments were performed using soil samples dosed with organic and inorganic contaminants (benzalkonium chloride and zinc) to demonstrate the mode of operation and the sensitivity of the bioassay. The EC50 values of zinc and benzalkonium chloride were calculated to be 171 and 221 mg kg-1 soil, respectively. The toxic response provided by the bioassay can thus predict the effect of soil pollutants on the autochthonous nitrifying bacteria.

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 use...

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 in...

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 generally...

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 in...

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 generally...

Dietary supplementation with zinc oxide decreases expression of the stem cell factor in the small intestine of weanling pigs.

PubMed

Ou, Deyuan; Li, Defa; Cao, Yunhe; Li, Xilong; Yin, Jingdong; Qiao, Shiyan; Wu, Guoyao

2007-12-01

Dietary supplementation with a high level of zinc oxide (ZnO) has been shown to reduce the incidence of diarrhea in weanling pigs, but the underlying mechanisms remain largely unknown. Intestinal-mucosal mast cells, whose maturation and proliferation is under the control of the stem cell factor (SCF), play an important role in the etiology of diarrhea by releasing histamine. The present study was conducted to test the novel hypothesis that supplementing ZnO to the diet for weanling piglets may inhibit SCF expression in the small intestine, thereby reducing the number of mast cells, histamine release, and diarrhea. In Experiment 1, 32 piglets (28 days of age) were weaned and fed diets containing 100 or 3000 mg zinc/kg (as ZnO) for 10 days (16 piglets per group). In Experiment 2, two groups of 28-day-old piglets (8 piglets per group) were fed the 100- or 3000-mg zinc/kg diet as in Experiment 1, except that they were pair-fed the same amounts of feed. Supplementation with a high level of ZnO reduced the incidence of diarrhea in weanling piglets. Dietary Zn supplementation reduced expression of the SCF gene at both mRNA and protein levels, the number of mast cells in the mucosa and submucosa of the small intestine and histamine release from mucosal mast cells. Collectively, our results indicate that dietary supplementation with ZnO inhibits SCF expression in the small intestine, leading to reductions in the number of mast cells and histamine release. These findings may have important implications for the prevention of weaning-associated diarrhea in piglets.

Enhanced synergism of antibiotics with zinc oxide nanoparticles against extended spectrum β-lactamase producers implicated in urinary tract infections

NASA Astrophysics Data System (ADS)

Bhande, Rashmi M.; Khobragade, C. N.; Mane, R. S.; Bhande, S.

2013-01-01

In this study, enhanced synergistic bioactivity of zinc oxide nanoparticles (ZnO NPs) with β-lactam antibiotics were evaluated against a panel of clinically isolated extended spectrum β-lactamase producers implicated in urinary tract infections. Chemically synthesized zinc oxide nanoparticles (15 nm) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmittance electron microscopy (HR-TEM), selective area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV-Visible spectrophotometry techniques. The antimicrobial potency (10 ± 0.66, 12, 11.33 ± 1.10, and 0.7 ± 0.66 mm inhibiting zone) and minimum inhibitory concentrations (80, 60, 30, 50 μg/ml) of ZnO NPs were tested separately whereas time-kill and membrane leakage assays were evaluated in combination with ZnO NPs+ cefotaxime, ampicillin, ceftriaxone, cefepime against the β-lactamase producer strains of E. coli, K. pneumoniae, S. paucimobilis, and P. aeruginosa, respectively. Time-kill curve dynamics of ZnO NPs with β-lactam antibiotics revealed enhanced bactericidal activity (50, 85, 58, 50 % fold inhibition) by delaying the exponential and stationary phases of all isolates when tested separately. Posttime-kill effect was studied on cell membrane by assaying leakage of reducing sugars (130.2, 124.7, 137, and 115.8 μg/bacterial dry weight of 1 mg (μg/mg) and proteins (15, 10, 16, 18 μg/mg). These assays revealed that membrane leakage was due to synergism of ZnO NPs+ β-lactam antibiotics which successfully damage cell membrane thereby leading to death of all ESBL producers. The results demonstrate the utilization of ZnO NPs as a potentiator of β-lactam antibiotics and suggest the possibility to use nanoparticles in a combination therapy to treat UTI.

Aminolysis of polyethylene terephthalate surface along with in situ synthesis and stabilizing ZnO nanoparticles using triethanolamine optimized with response surface methodology.

PubMed

Poortavasoly, Hajar; Montazer, Majid; Harifi, Tina

2016-01-01

This research concerned the simultaneous polyester surface modification and synthesis of zinc oxide nano-reactors to develop durable photo-bio-active fabric with variable hydrophobicity/hydrophilicity under sunlight. For this purpose, triethanolamine (TEA) was applied as a stabilizer and pH adjusting chemical for the aminolysis of polyester surface and enhancing the surface reactivity along with synthesis and deposition of ZnO nanoparticles on the fabric. Therefore, TEA played a crucial role in providing the alkaline condition for the preparation of zinc oxide nanoparticles and acting as stabilizer controlling the size of the prepared nanoparticles. The stain-photodegradability regarded as self-cleaning efficiency, wettability and weight change under the process was optimized based on zinc acetate and TEA concentrations, using central composite design (CCD). Findings also suggested the potential of the prepared fabric in inhibiting Staphylococcus aureus and Escherichia coli bacteria growth with greater than 99.99% antibacterial efficiency. Besides, the proposed treatment had no detrimental effect on tensile strength and hand feeling of the polyester fabric. Copyright © 2015 Elsevier B.V. All rights reserved.

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 § 73.1991...

Electrocontact material based on silver dispersion-strengthened by nickel, titanium, and zinc oxides

NASA Astrophysics Data System (ADS)

Zeer, G. M.; Zelenkova, E. G.; Belousov, O. V.; Beletskii, V. V.; Nikolaev, S. V.; Ledyaeva, O. N.

2017-09-01

Samples of a composite electrocontact material based on silver strengthened by the dispersed phases of zinc and titanium oxides have been investigated by the electron microscopy and energy dispersive X-ray spectroscopy. A uniform distribution of the oxide phases containing 2 wt % zinc oxide in the initial charge has been revealed. The increase in the amount of zinc oxide leads to an increase of the size of the oxide phases. It has been shown that at the zinc oxide content of 2 wt %, the minimum wear is observed in the process of electroerosion tests; at 3 wt %, an overheating and welding of the contacts are observed.

Time-resolved fluorescence and ultrafast energy transfer in a zinc (hydr)oxide-graphite oxide mesoporous composite

NASA Astrophysics Data System (ADS)

Secor, Jeff; Narinesingh, Veeshan; Seredych, Mykola; Giannakoudakis, Dimitrios A.; Bandosz, Teresa; Alfano, Robert R.

2015-01-01

Ultrafast energy decay kinetics of a zinc (hydr)oxide-graphite oxide (GO) composite is studied via time-resolved fluorescence spectroscopy. The time-resolved emission is spectrally decomposed into emission regions originating from the zinc (hydr)oxide optical gap, surface, and defect states of the composite material. The radiative lifetime of deep red emission becomes an order of magnitude longer than that of GO alone while the radiative lifetime of the zinc optical gap is shortened in the composite. An energy transfer scheme from the zinc (hydr)oxide to GO is considered.

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

NASA Astrophysics Data System (ADS)

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

2012-06-01

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

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in...

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The color additive zinc oxide shall conform in...

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc oxide is a white or yellow-white amorphous...

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc oxide is a white or yellow-white amorphous...

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc oxide is a white or yellow-white amorphous...

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

2014-06-07

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.

Enhanced anti-inflammatory potential of cinnamate-zinc layered hydroxide in lipopolysaccharide-stimulated RAW 264.7 macrophages

PubMed Central

Adewoyin, Malik; Mohsin, Sumaiyah Megat Nabil; Arulselvan, Palanisamy; Hussein, Mohd Zobir; Fakurazi, Sharida

2015-01-01

Background Cinnamic acid (CA) is a phytochemical originally derived from Cinnamomum cassia, a plant with numerous pharmacological properties. The intercalation of CA with a nanocarrier, zinc layered hydroxide, produces cinnamate-zinc layered hydroxide (ZCA), which has been previously characterized. Intercalation is expected to improve the solubility and cell specificity of CA. The nanocarrier will also protect CA from degradation and sustain its release. The aim of this study was to assess the effect of intercalation on the anti-inflammatory capacity of CA. Methods In this study, the anti-inflammatory activity of ZCA was investigated and compared with that of nonintercalated CA. Evaluations were based on the capacity of ZCA and CA to modulate the release of nitric oxide, prostaglandin E2, interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), IL-1β, and IL-10 in lipopolysaccharide-induced RAW 264.7 cells. Additionally, the expression of proinflammatory enzymes, ie, cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor kappa B (NF-κB), were examined. Results Although both ZCA and CA downregulated nitric oxide, prostaglandin E2, tumor necrosis factor alpha, IL-1β, and IL-6, ZCA clearly displayed better activity. Similarly, expression of cyclooxygenase-2 and inducible nitric oxide synthase were inhibited in samples treated with ZCA and CA. The two compounds effectively inactivated the transcription factor NF-κB, but the anti-inflammatory cytokine, IL-10, was significantly upregulated by ZCA only. Conclusion The present findings suggest that ZCA possesses better anti-inflammatory potential than CA, while zinc layered hydroxide had little or no effect, and these results were comparable with the positive control. PMID:25995619

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

Zinc triggers microglial activation.

PubMed

Kauppinen, Tiina M; Higashi, Youichirou; Suh, Sang Won; Escartin, Carole; Nagasawa, Kazuki; Swanson, Raymond A

2008-05-28

Microglia are resident immune cells of the CNS. When stimulated by infection, tissue injury, or other signals, microglia assume an activated, "ameboid" morphology and release matrix metalloproteinases, reactive oxygen species, and other proinflammatory factors. This innate immune response augments host defenses, but it can also contribute to neuronal death. Zinc is released by neurons under several conditions in which microglial activation occurs, and zinc chelators can reduce neuronal death in animal models of cerebral ischemia and neurodegenerative disorders. Here, we show that zinc directly triggers microglial activation. Microglia transfected with a nuclear factor-kappaB (NF-kappaB) reporter gene showed a severalfold increase in NF-kappaB activity in response to 30 microm zinc. Cultured mouse microglia exposed to 15-30 microm zinc increased nitric oxide production, increased F4/80 expression, altered cytokine expression, and assumed the activated morphology. Zinc-induced microglial activation was blocked by inhibiting NADPH oxidase, poly(ADP-ribose) polymerase-1 (PARP-1), or NF-kappaB activation. Zinc injected directly into mouse brain induced microglial activation in wild-type mice, but not in mice genetically lacking PARP-1 or NADPH oxidase activity. Endogenous zinc release, induced by cerebral ischemia-reperfusion, likewise induced a robust microglial reaction, and this reaction was suppressed by the zinc chelator CaEDTA. Together, these results suggest that extracellular zinc triggers microglial activation through the sequential activation of NADPH oxidase, PARP-1, and NF-kappaB. These findings identify a novel trigger for microglial activation and a previously unrecognized mechanism by which zinc may contribute to neurological disorders.

The Interaction of Implant Luting Cements and Oral Bacteria Linked to Peri-Implant Disease: An In Vitro Analysis of Planktonic and Biofilm Growth--A Preliminary Study.

PubMed

Raval, Neal C; Wadhwani, Chandur P K; Jain, Sumita; Darveau, Richard P

2015-12-01

There is little consensus on the most appropriate cement to use when restoring a cement-retained, implant-supported restoration. One consideration should be the interaction of pathogenic oral bacteria with restorative cements. To determine how oral bacteria associated with peri-implant disease grow in the presence of implant cements. Five test cements with varying composition (zinc oxide-eugenol [TBO], eugenol-free zinc oxide [TBNE], zinc orthophosphate [FL], and two resin cements [PIC and ML]) were used to fabricate specimen disks. The disks were submerged in bacterial suspensions of either Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, or Porphyromonas gingivalis. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures (OD600 ). Positive controls (media and bacteria without cement disks) and negative controls (media alone) were similarly evaluated. The mean and standard deviations (SD) were calculated for planktonic growth from three separate experiments. ANOVA statistical analysis with post hoc Tukey tests was performed where differences existed (p < .05). Selected cement disks (TBO and ML) were further examined for bacterial biofilm growth. Surface bacteria were removed and grown on agar media, and colony-forming units (CFUs) were quantified. Planktonic growth for both A. actinomycetemcomitans and P. gingivalis was significantly inhibited (p < .05) when grown in the presence of cement disks consisting of TBNE, PIC, FL, and TBO. In contrast, neither of these bacteria displayed growth inhibition in the presence of ML cement disks. F. nucleatum growth was also significantly inhibited by PIC, FL. and TBO (p < .05), but not by ML and TBNE cement disks. CFU counts for the biofilm study for TBO gave minimal and, in some instances, no bacterial adherence and growth, in contrast to ML, which supported substantially greater bacterial biofilm growth. Cements display differing abilities to inhibit both planktonic and biofilm bacterial growth. Cements with the ability to reduce planktonic or biofilm growth of the test bacteria may be advantageous in reducing peri-implant disease. Understanding the microbial growth-inhibiting characteristics of different cement types should be considered important in the selection criteria. © 2014 Wiley Periodicals, Inc.

Regeneration of zinc halide catalyst used in the hydrocracking of polynuclear hydrocarbons

DOEpatents

Gorin, Everett

1978-01-01

Improved recovery of spent molten zinc halide hydro-cracking catalyst is achieved in the oxidative vapor phase regeneration thereof by selective treatment of the zinc oxide carried over by the effluent vapors from the regeneration zone with hydrogen halide gas under conditions favoring the reaction of the zinc oxide with the hydrogen halide, whereby regenerated zinc halide is recovered in a solids-free state with little loss of zinc values.

Arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair

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

Sun, Xi; Zhou, Xixi; Du, Libo

2014-01-15

Inhibition of DNA repair is a recognized mechanism for arsenic enhancement of ultraviolet radiation-induced DNA damage and carcinogenesis. Poly(ADP-ribose) polymerase-1 (PARP-1), a zinc finger DNA repair protein, has been identified as a sensitive molecular target for arsenic. The zinc finger domains of PARP-1 protein function as a critical structure in DNA recognition and binding. Since cellular poly(ADP-ribosyl)ation capacity has been positively correlated with zinc status in cells, we hypothesize that arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair. To test this hypothesis, we compared the effects ofmore » arsenite exposure with zinc deficiency, created by using the membrane-permeable zinc chelator TPEN, on 8-OHdG formation, PARP-1 activity and zinc binding to PARP-1 in HaCat cells. Our results show that arsenite exposure and zinc deficiency had similar effects on PARP-1 protein, whereas supplemental zinc reversed these effects. To investigate the molecular mechanism of zinc loss induced by arsenite, ICP-AES, near UV spectroscopy, fluorescence, and circular dichroism spectroscopy were utilized to examine arsenite binding and occupation of a peptide representing the first zinc finger of PARP-1. We found that arsenite binding as well as zinc loss altered the conformation of zinc finger structure which functionally leads to PARP-1 inhibition. These findings suggest that arsenite binding to PARP-1 protein created similar adverse biological effects as zinc deficiency, which establishes the molecular mechanism for zinc supplementation as a potentially effective treatment to reverse the detrimental outcomes of arsenic exposure. - Highlights: • Arsenite binding is equivalent to zinc deficiency in reducing PARP-1 function. • Zinc reverses arsenic inhibition of PARP-1 activity and enhancement of DNA damage. • Arsenite binding and zinc loss alter the conformation of zinc finger structure.« less

21 CFR 73.1991 - Zinc oxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... amounts consistent with good manufacturing practice. (d) Labeling. The color additive and any mixtues... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1991 Zinc oxide. (a) Identity. (1) The color additive zinc...). It is principally composed of Zn. (2) Color additive mixtures for drug use made with zinc oxide may...

Inhibition of vaccinia virus maturation by zinc chloride.

PubMed Central

Katz, E; Margalith, E

1981-01-01

Zinc chloride (0.1 mM) inhibited by 96.4% the growth of vaccinia virus in HeLa cells. Approximately 50% inhibition in formation of particles that sedimented in sucrose gradients similarly to vaccinia virions occurred in the presence of zinc ions. Whereas the synthesis of the viral deoxyribonucleic acid was not affected by zinc chloride, a decrease in the overall synthesis of viral polypeptides and inhibition of the cleavage of precursors to the core polypeptides were observed. Images PMID:7347557

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 ...

Critical Role of Zinc as Either an Antioxidant or a Prooxidant in Cellular Systems

PubMed Central

2018-01-01

Zinc is recognized as an essential trace metal required for human health; its deficiency is strongly associated with neuronal and immune system defects. Although zinc is a redox-inert metal, it functions as an antioxidant through the catalytic action of copper/zinc-superoxide dismutase, stabilization of membrane structure, protection of the protein sulfhydryl groups, and upregulation of the expression of metallothionein, which possesses a metal-binding capacity and also exhibits antioxidant functions. In addition, zinc suppresses anti-inflammatory responses that would otherwise augment oxidative stress. The actions of zinc are not straightforward owing to its numerous roles in biological systems. It has been shown that zinc deficiency and zinc excess cause cellular oxidative stress. To gain insights into the dual action of zinc, as either an antioxidant or a prooxidant, and the conditions under which each role is performed, the oxidative stresses that occur in zinc deficiency and zinc overload in conjunction with the intracellular regulation of free zinc are summarized. Additionally, the regulatory role of zinc in mitochondrial homeostasis and its impact on oxidative stress are briefly addressed. PMID:29743987

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Testing of WW-85

DTIC Science & Technology

2005-11-21

secondary ROS, superoxide (O2 -) and hydrogen peroxide (H2O2), the latter can react via Fenton chemistry with cellular metal ions to produce additional ·OH...nitrogen dioxide (NO2), and nitrosonium cation. Oxidations of thiols, sulfides, transition metal complexes, deoxyribose, phenols and other...respiratory chain and disruption of the zinc-thiolate center at the active site of enzymes. Peroxynitrite has been shown to inhibit a variety of ion

Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties

PubMed Central

Lim, Karkeng; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Al-Hardan, N.H.; Mansor, Ishak; Chiu, Weesiong

2016-01-01

In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions. PMID:28773425

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

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

Kavitha, M.K.; Haripadmam, P.C.; Gopinath, Pramod

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 novelmore » 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.« less

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

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

PubMed

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

2017-12-01

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

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

NASA Astrophysics Data System (ADS)

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

2006-07-01

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

Mechanical properties of bioplastics cassava starch film with Zinc Oxide nanofiller as reinforcement

NASA Astrophysics Data System (ADS)

Harunsyah; Yunus, M.; Fauzan, Reza

2017-06-01

This study focuses on investigating the influence of zinc oxide nanofiller on the mechanical properties of bioplastic cassava starch films. Bioplastic cassava starch film-based zinc oxide reinforced composite biopolymeric films were prepared by casting technique. The content of zinc oxide in the bioplastic films was varied from 0.2%, 0.4%, 0.6%, 0.8% and 1.0% (w/w) by weight of starch. Surface morphologies of the composites bioplastic films were examined by scanning electron microscope (SEM).The result showed that the Tensile strength (TS) was improved significantly with the additional of zinc oxide but the elongation at break (EB %) of the composites was decreased. The maximum tensile strength obtained was 22.30 kgf / mm on the additional of zinc oxide by 0.6% and plastilizer by 25%. Based on data of FTIR, the produced film plastic did not change the group function and it can be concluded that theinteraction in film plastic produced was only a physical interaction. Biodegradable plastic film based on cassava starch-zinc oxide and plasticizer glycerol showed that interesting mechanical properties being transparent, clear, homogeneous, flexible, and easily handled.

Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications

PubMed Central

Skuza, J. R.; Scott, D. W.; Mundle, R. M.; Pradhan, A. K.

2016-01-01

We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5–10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT. PMID:26884225

Morphological tuned preparation of zinc oxide: reduced graphene oxide composites for non-enzymatic fluorescence glucose sensing and enhanced photocatalysis

NASA Astrophysics Data System (ADS)

Sivalingam, Muthu Mariappan; Balasubramanian, Karthikeyan

2016-07-01

Zinc oxide: reduced graphene oxide (ZnO:rgo) composites with varying ZnO morphologies have been synthesized towards the application of non-enzymatic fluorescence (FL) glucose sensor and photocatalysis for methylene blue (MB) degradation. The phase structure of ZnO has confirmed by X-ray diffraction studies, and the band gap calculations were done by UV absorption spectra. Scanning electron microscope and Raman spectra revealed the morphological change and the vibrational studies of the prepared samples, respectively. The quenching of the FL emission band of ZnO:rgo composite sample confirmed the transfer of electrons from ZnO to rgo which inhibit the exciton recombination process. The non-enzymatic FL glucose sensing was carried out by the addition of dextrose glucose ( d-glucose) into the ZnO:rgo composite solution, which shows strong relationship between glucose concentration and the FL intensity. The photocatalytic studies showed that composite with high surface to volume ratio exhibits a maximum degradation of MB over 93 %. Our combined results ensured that the ZnO:rgo composites with varying morphologies could be an effective system for applications such as FL-based glucose sensing and photocatalytic degradation.

Improved synthesis of fine zinc borate particles using seed crystals

NASA Astrophysics Data System (ADS)

Gürhan, Deniz; Çakal, Gaye Ö.; Eroğlu, İnci; Özkar, Saim

2009-03-01

Zinc borate is a flame retardant additive used in polymers, wood applications and textile products. There are different types of zinc borate having different chemical compositions and structures. In this study, the production of zinc borate having the molecular formula of 2ZnO·3B 2O 3·3.5H 2O was reexamined by studying the effects of reaction parameters on the properties of product as well as the reaction kinetics. Production of zinc borate from the reaction of boric acid and zinc oxide in the presence of seed crystals was performed in a continuously stirred, temperature-controlled batch reactor having a volume of 1.5 L. Samples taken in regular time intervals during the experiments were analyzed for the concentration of zinc oxide and boron oxide in the solid as well as for the conversion of zinc oxide to zinc borate versus time. The zinc borate production reaction was fit to the logistic model. The reaction rate, reaction completion time, composition and particle size distribution of zinc borate product were determined by varying the following parameters: the boric acid to zinc oxide ratio (H 3BO 3:ZnO=3:1, 3.5:1, 5:1 and 7:1), the particle size of zinc oxide (10 and 25 μm), stirring rate (275, 400, 800 and 1600 rpm), temperature (75, 85 and 95 °C) and the size of seed crystals (10 and 2 μm). The products were also analyzed for particle size distribution. The experimental results showed that the reaction rate increases with the increase in H 3BO 3:ZnO ratio, particle size of zinc oxide, stirring rate and temperature. Concomitantly, the reaction completion time is decreased by increasing the H 3BO 3:ZnO ratio, stirring rate and temperature. The average particle sizes of the zinc borate products are in the range 4.3-16.6 μm (wet dispersion analysis).

A review of zinc oxide mineral beneficiation using flotation method.

PubMed

Ejtemaei, Majid; Gharabaghi, Mahdi; Irannajad, Mehdi

2014-04-01

In recent years, extraction of zinc from low-grade mining tailings of oxidized zinc has been a matter of discussion. This is a material which can be processed by flotation and acid-leaching methods. Owing to the similarities in the physicochemical and surface chemistry of the constituent minerals, separation of zinc oxide minerals from their gangues by flotation is an extremely complex process. It appears that selective leaching is a promising method for the beneficiation of this type of ore. However, with the high consumption of leaching acid, the treatment of low-grade oxidized zinc ores by hydrometallurgical methods is expensive and complex. Hence, it is best to pre-concentrate low-grade oxidized zinc by flotation and then to employ hydrometallurgical methods. This paper presents a critical review on the zinc oxide mineral flotation technique. In this paper, the various flotation methods of zinc oxide minerals which have been proposed in the literature have been detailed with the aim of identifying the important factors involved in the flotation process. The various aspects of recovery of zinc from these minerals are also dealt with here. The literature indicates that the collector type, sulfidizing agent, pH regulator, depressants and dispersants types, temperature, solid pulp concentration, and desliming are important parameters in the process. The range and optimum values of these parameters, as also the adsorption mechanism, together with the resultant flotation of the zinc oxide minerals reported in the literature are summarized and highlighted in the paper. This review presents a comprehensive scientific guide to the effectiveness of flotation strategy. Copyright © 2013 Elsevier B.V. All rights reserved.

Attrition resistant, zinc titanate-containing, reduced sulfur sorbents and methods of use thereof

DOEpatents

Vierheilig, Albert A.; Gupta, Raghubir P.; Turk, Brian S.

2006-06-27

Reduced sulfur gas species (e.g., H.sub.2S, COS and CS.sub.2) are removed from a gas stream by compositions wherein a zinc titanate ingredient is associated with a metal oxide-aluminate phase material in the same particle species. Nonlimiting examples of metal oxides comprising the compositions include magnesium oxide, zinc oxide, calcium oxide, nickel oxide, etc.

Pyrrolidine dithiocarbamate-zinc(II) and -copper(II) complexes induce apoptosis in tumor cells by inhibiting the proteasomal activity☆

PubMed Central

Milacic, Vesna; Chen, Di; Giovagnini, Lorena; Diez, Alejandro; Fregona, Dolores; Dou, Q. Ping

2013-01-01

Zinc and copper are trace elements essential for proper folding, stabilization and catalytic activity of many metalloenzymes in living organisms. However, disturbed zinc and copper homeostasis is reported in many types of cancer. We have previously demonstrated that copper complexes induced proteasome inhibition and apoptosis in cultured human cancer cells. In the current study we hypothesized that zinc complexes could also inhibit the proteasomal chymotrypsin-like activity responsible for subsequent apoptosis induction. We first showed that zinc(II) chloride was able to inhibit the chymotrypsin-like activity of a purified 20S proteasome with an IC50 value of 13.8 μM, which was less potent than copper(II) chloride (IC50 5.3 μM). We then compared the potencies of a pyrrolidine dithiocarbamate (PyDT)-zinc(II) complex and a PyDT-copper(II) complex to inhibit cellular proteasomal activity, suppress proliferation and induce apoptosis in various human breast and prostate cancer cell lines. Consistently, zinc complex was less potent than copper complex in inhibiting the proteasome and inducing apoptosis. Additionally, zinc and copper complexes appear to use somewhat different mechanisms to kill tumor cells. Zinc complexes were able to activate calpain-, but not caspase-3-dependent pathway, while copper complexes were able to induce activation of both proteases. Furthermore, the potencies of these PyDT-metal complexes depend on the nature of metals and also on the ratio of PyDT to the metal ion within the complex, which probably affects their stability and availability for interacting with and inhibiting the proteasome in tumor cells. PMID:18501397

Sulfur-Doped Zinc Oxide (ZnO) Nanostars: Synthesis and Simulation of Growth Mechanism

DTIC Science & Technology

2011-10-01

Zinc Oxide ( ZnO ) Nanostars: Synthesis and Simulation of Growth Mechanism Jinhyun Cho1, Qiubao Lin2,3, Sungwoo...characterization, and ab initio simulations of star-shaped hexagonal zinc oxide ( ZnO ) nanowires. The ZnO nanostructures were synthesized by a low...Introduction Zinc oxide ( ZnO ) is a wide bandgap (3.37 eV), Ⅱ–Ⅵ semiconductor of great interest for optoelectronic applications [1–3]. Its

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 Supplements 1 § 582.5991 Zinc oxide. (a) Product. Zinc...

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, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5991 Zinc oxide. (a) Product. Zinc...

Chitosan/zinc oxide-polyvinylpyrrolidone (CS/ZnO-PVP) nanocomposite for better thermal and antibacterial activity.

PubMed

Karpuraranjith, M; Thambidurai, S

2017-11-01

A new biopolymer based ZnO-PVP nanocomposite was successfully synthesized by single step in situ precipitation method using chitosan as biosurfactant, zinc chloride as a source material, PVP as stabilizing agent and sodium hydroxide as precipitating agent. The chemical bonding and crystalline behaviors of chitosan, zinc oxide and PVP were confirmed by FT-IR and XRD analysis. The biopolymer connected ZnO particles intercalated PVP matrix was layer and rod like structure appeared in nanometer range confirmed by HR-SEM and TEM analysis. The surface topography image of CS/ZnO-PVP nanocomposite was obtained in the average thickness of 12nm was confirmed by AFM analysis. Thermal stability of cationic biopolymer based ZnO intercalated PVP has higher stability than CS-PVP and chitosan. Consequently, antimicrobial activity of chitosan/ZnO-PVP matrix acts as a better microbial inhibition activity than PVP-ZnO nanocomposite. The obtained above results demonstrate that CS and ZnO intercalated PVP matrix has better reinforced effect than other components. Therefore, Chitosan/ZnO-PVP nanocomposite may be a promising material for the biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Zinc triggers microglial activation

PubMed Central

Kauppinen, Tiina M.; Higashi, Youichirou; Suh, Sang Won; Escartin, Carole; Nagasawa, Kazuki; Swanson, Raymond A.

2009-01-01

Microglia are resident immune cells of the central nervous system. When stimulated by infection, tissue injury, or other signals, microglia assume an activated, “amoeboid” morphology and release matrix metalloproteinases, reactive oxygen species, and other pro-inflammatory factors. This innate immune response augments host defenses, but it can also contribute to neuronal death. Zinc is released by neurons under several conditions in which microglial activation occurs, and zinc chelators can reduce neuronal death in animal models of cerebral ischemia and neurodegenerative disorders. Here we show that zinc directly triggers microglial activation. Microglia transfected with an NF-kB reporter gene showed a several-fold increase in NF-kB activity in response to 30 μM zinc. Cultured mouse microglia exposed to 15 – 30 μM zinc increased nitric oxide production, increased F4/80 expression, altered cytokine expression, and assumed the activated morphology. Zinc-induced microglial activation was blocked by inhibiting NADPH oxidase, poly(ADP-ribose) polymerase-1 (PARP-1), or NF-κB activation. Zinc injected directly into mouse brain induced microglial activation in wild-type mice, but not in mice genetically lacking PARP-1 or NADPH oxidase activity. Endogenous zinc release, induced by cerebral ischemia-reperfusion, likewise induced a robust microglial reaction, and this reaction was suppressed by the zinc chelator CaEDTA. Together, these results suggest that extracellular zinc triggers microglial activation through the sequential activation of NADPH oxidase, PARP-1, and NF-κB. These findings identify a novel trigger for microglial activation and a previously unrecognized mechanism by which zinc may contribute to neurological disorders. PMID:18509044

Effects of cadmium and zinc on solar-simulated light-irradiated cells: potential role of zinc-metallothionein in zinc-induced genoprotection.

PubMed

Jourdan, Eric; Emonet-Piccardi, Nathalie; Didier, Christine; Beani, Jean-Claude; Favier, Alain; Richard, Marie-Jeanne

2002-09-15

Zinc is an essential oligoelement for cell growth and cell survival and has been demonstrated to protect cells from oxidative stress induced by UVA or from genotoxic stress due to UVB. In a recent work we demonstrated that the antioxidant role of zinc could be related to its ability to induce metallothioneins (MTs). In this study we identified the mechanism of zinc protection against solar-simulated light (SSL) injury. Cultured human keratinocytes (HaCaT) were used to examine MTs expression and localization in response to solar-simulated radiation. We found translocation to the nucleus, with overexpression of MTs in irradiated cells, a novel observation. The genoprotective effect of zinc was dependent on time and protein synthesis. DNA damage was significantly decreased after 48 h of ZnCl(2) (100 microM) treatment and is inhibited by actinomycin D. ZnCl(2) treatment (100 microM) led to an intense induction, redistribution, and accumulation of MT in the nucleus of irradiated cells. MT expression correlated with the time period of ZnCl(2) treatment. CdCl(2), a potent MT inducer, did not show any genoprotection, although the MTs were expressed in the nucleus. Overall our findings demonstrate that MTs could be a good candidate for explaining the genoprotection mediated by zinc on irradiated cells.

Analysis of Zinc Oxide Thin Films Synthesized by Sol-Gel via Spin Coating

NASA Astrophysics Data System (ADS)

Wolgamott, Jon Carl

Transparent conductive oxides are gaining an increasingly important role in optoelectronic devices such as solar cells. Doped zinc oxide is a candidate as a low cost and nontoxic alternative to tin doped indium oxide. Lab results have shown that both n-type and p-type zinc oxide can be created on a small scale. This can allow zinc oxide to be used as either an electrode as well as a buffer layer to increase efficiency and protect the active layer in solar cells. Sol-gel synthesis is emerging as a low temperature, low cost, and resource efficient alternative to producing transparent conducting oxides such as zinc oxide. For sol-gel derived zinc oxide thin films to reach their potential, research in this topic must continue to optimize the known processing parameters and expand to new parameters to tighten control and create novel processing techniques that improve performance. The processing parameters of drying and annealing temperatures as well as cooling rate were analyzed to see their effect on the structure of the prepared zinc oxide thin films. There were also preliminary tests done to modify the sol-gel process to include silver as a dopant to produce a p-type thin film. The results from this work show that the pre- and post- heating temperatures as well as the cooling rate all play their own unique role in the crystallization of the film. Results from silver doping show that more work needs to be done to create a sol-gel derived p-type zinc oxide thin film.

Zinc and redox signaling: perturbations associated with cardiovascular disease and diabetes mellitus.

PubMed

Foster, Meika; Samman, Samir

2010-11-15

Cellular signal transduction pathways are influenced by the zinc and redox status of the cell. Numerous chronic diseases, including cardiovascular disease (CVD) and diabetes mellitus (DM), have been associated with impaired zinc utilization and increased oxidative stress. In humans, mutations in the MT-1A and ZnT8 genes, both of which are involved in the maintenance of zinc homeostasis, have been linked with DM development. Changes in levels of intracellular free zinc may exacerbate oxidative stress in CVD and DM by impacting glutathione homeostasis, nitric oxide signaling, and nuclear factor-kappa B-dependent cellular processes. Zinc ions have been shown to influence insulin and leptin signaling via the phosphoinositide 3′-kinase/Akt pathway, potentially linking an imbalance of zinc at the cellular level to insulin resistance and dyslipidemia. The oxidative modification of cysteine residues in zinc coordination sites in proteins has been implicated in cellular signaling and regulatory pathways. Despite the many interactions between zinc and cellular stress responses, studies investigating the potential therapeutic benefit of zinc supplementation in the prevention and treatment of oxidative stress-related chronic disease in humans are few and inconsistent. Further well-designed randomized controlled trials are needed to determine the effects of zinc supplementation in populations at various stages of CVD and DM progression.

40 CFR 63.11167 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... melt cadmium or produce cadmium oxide from the cadmium recovered in the zinc production process... engaged in the production, or any intermediate process in the production, of zinc or zinc oxide from zinc... Sources-Zinc, Cadmium, and Beryllium Other Requirements and Information § 63.11167 What definitions apply...

Human eosinophils are direct targets to nanoparticles: Zinc oxide nanoparticles (ZnO) delay apoptosis and increase the production of the pro-inflammatory cytokines IL-1β and IL-8.

PubMed

Silva, Luis Rafael; Girard, Denis

2016-09-30

Zinc oxide NPs (ZnO) have been recently proposed as novel candidates for the treatment of allergic inflammatory diseases. Paradoxically, recent data suggested that ZnO could cause eosinophilic airway inflammation in rodents. Despite the above observations, there are currently no studies reporting direct interaction between a given NP and human eosinophils themselves. In this study, freshly isolated human eosinophils were incubated with ZnO and several cellular functions were studied. We found that ZnO delay human eosinophil apoptosis, partially by inhibiting caspases and by preventing caspase-4 and Bcl-xL degradation. ZnO do not induce production of reactive oxygen species but increase de novo protein synthesis. In addition, ZnO were found to increase the production of the proinflammatory IL-1β and IL-8 cytokines. Using a pharmacological approach, we demonstrated that inhibition of caspase-1 reversed the ability of ZnO to induce IL-1β and IL-8 production, whereas inhibition of caspase-4 only reversed that of IL-8. Our results indicate the necessity of conducting studies to determine the potential of using NP as nanotherapies, particularly in diseases in which eosinophils may be involved. We conclude that, indeed, human eosinophils represent potential new direct targets to NPs, ZnO in the present case. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Excess zinc ions are a competitive inhibitor for carboxypeptidase A

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

Hirose, J.; Ando, S.; Kidani, Y.

The mechanism for inhibition of enzyme activity by excess zinc ions has been studied by kinetic and equilibrium dialysis methods at pH 8.2, I = 0.5 M. With carboxypeptidase A (bovine pancreas), peptide (carbobenzoxyglycyl-L-phenylalanine and hippuryl-L-phenylalanine) and ester (hippuryl-L-phenyl lactate) substrates were inhibited competitively by excess zinc ions. The K/sub i/ values for excess zinc ions with carboxypeptidase A at pH 8.2 are all similar. The apparent constant for dissociation of excess zinc ions from carboxypeptidase A was also obtained by equilibrium dialysis at pH 8.2 and was 2.4 x 10/sup -5/ M, very close to the K/sub i/ valuesmore » above. With arsanilazotyrosine-248 carboxypeptidase A ((Azo-CPD)Zn)), hippuryl-L-phenylalanine, carbobenzoxyglycyl-L-phenylalanine, and hippuryl-L-phenyl lactate were also inhibited with a competitive pattern by excess zinc ions, and the K/sub i/ values were (3.0-3.5) x 10/sup -5/ M. The apparent constant for dissociation of excess zinc ions from arsanilazotyrosine-248 carboxypeptidase A, which was obtained from absorption changes at 510 nm, was 3.2 x 10/sup -5/ M and is similar to the K/sub i/ values for ((Azo-CPD)Zn). The apparent dissociation and inhibition constants, which were obtained by inhibition of enzyme activity and spectrophotometric and equilibrium dialysis methods with native carboxypeptidase A and arsanilazotyrosine-248 carboxypeptidase A, were almost the same. This agreement between the apparent dissociation and inhibition constants indicates that the zinc binding to the enzymes directly relates to the inhibition of enzyme activity by excess zinc ions. Excess zinc ions were competitive inhibitors for both peptide and ester substrates. This behavior is believed to arise by the excess zinc ions fixing the enzyme in a conformation to which the substrates cannot bind.« less

Zinc oxide nanoparticles inhibit murine photoreceptor-derived cell proliferation and migration via reducing TGF-β and MMP-9 expression in vitro.

PubMed

Guo, Da Dong; Li, Qing Ning; Li, Chun Min; Bi, Hong Sheng

2015-04-01

To investigate behaviour and expression of transforming growth factor-β (TGF-β) and matrix metalloproteinases (MMP-9) in murine photoreceptor-derived cells (661W) after incubation with zinc oxide (ZnO) nanoparticles. We explored effects of ZnO nanoparticles on 661W cells using a real-time cell electronic sensing system, flow cytometry, multiple function microplate reading, real-time quantitative PCR detection system and enzyme-linked immunosorbent assay respectively. Our results indicate that ZnO nanoparticles induced overload of calcium and reactive oxygen species within cells, causing formation of apoptotic bodies, disruption of cell cycle distribution, and reduction in expression of TGF-β and MMP-9, to suppress cell proliferation and migration. Our findings show that disruption of intracellular calcium homoeostasis and overproduction of reactive oxygen species were closely associated with reduction of TGF-β and MMP-9 in 661W cells under ZnO nanoparticle treatment. Results of our study indicate that ZnO nanoparticles suppressed cell proliferation and migration, and reduced production of TGF-β and MMP-9 at both gene and protein levels. Our findings contribute to the understanding of the molecular mechanisms that reduced TGF-β and MMP-9 levels inhibit cell proliferation and migration under ZnO nanoparticle influence. © 2015 John Wiley & Sons Ltd.

Facile fabrication and characterization of chitosan-based zinc oxide nanoparticles and evaluation of their antimicrobial and antibiofilm activity

NASA Astrophysics Data System (ADS)

Dhillon, Gurpreet Singh; Kaur, Surinder; Brar, Satinder Kaur

2014-06-01

The present investigation deals with the facile synthesis and characterization of chitosan (CTS)-based zinc oxide (ZnO) nanoparticles (NPs) and their antimicrobial activities against pathogenic microorganisms. ZnO-CTS NPs were synthesized through two different methods: nano spray drying and precipitation, using various organic compounds (citric acid, glycerol, starch and whey powder) as stabilizers. Both the synthesis methods were simple and were devoid of any chemical usage. The detailed characterization of the NPs was carried out using UV-Vis spectroscopy, dynamic light scattering particle size analysis, zeta potential measurements and scanning electron microscopy, which confirmed the fabrication of NPs with different shapes and sizes. Antimicrobial assay of synthesized ZnO-CTS NPs was carried out against different pathogenic microbial strains ( Candida albicans, Micrococcus luteus and Staphylococcus aureus). The significant ( p < 0.05) inhibition of growth was observed for both M. luteus and S. aureus with ZnO-CTS NPs (with a concentration ranging from 0.625 to 0.156 mg/ml) as compared to control treatment. ZnO-CTS NPs also showed significant biofilm inhibition activity ( p < 0.05) against M. luteus and S. aureus. The study demonstrated the potential of ZnO-CTS NPs as antimicrobial and antibiofilm agents.

System for trapping and storing gases for subsequent chemical reduction to solids

DOEpatents

Vogel, John S [San Jose, CA; Ognibene, Ted J [Oakland, CA; Bench, Graham S [Livermore, CA; Peaslee, Graham F [Holland, MI

2009-11-03

A system for quantitatively reducing oxide gases. A pre-selected amount of zinc is provided in a vial. A tube is provided in the vial. The zinc and the tube are separated. A pre-selected amount of a catalyst is provided in the tube. Oxide gases are injected into the vial. The vial, tube, zinc, catalyst, and the oxide gases are cryogenically cooled. At least a portion of the vial, tube, zinc, catalyst, and oxide gases are heated.

Nanoscale lamellar photoconductor hybrids and methods of making same

DOEpatents

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

2013-02-05

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

Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor.

PubMed

Low, Sze Shin; Tan, Michelle T T; Loh, Hwei-San; Khiew, Poi Sim; Chiu, Wee Siong

2016-01-15

Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) in a linear range of 1-15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM(-1) with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P < 0.05) and efficient than the conventional agarose gel electrophoresis. Copyright © 2015 Elsevier B.V. All rights reserved.

Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

PubMed

Bunnell, Bryan E; Escobar, Jillian F; Bair, Kirsten L; Sutton, Mark D; Crane, John K

2017-01-01

Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx) and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

Topical zinc oxide vs. salicylic acid-lactic acid combination in the treatment of warts.

PubMed

Khattar, Joe A; Musharrafieh, Umayya M; Tamim, Hala; Hamadeh, Ghassan N

2007-04-01

Warts are a common dermatologic problem. Treatment is painful, prolonged, and can cause scarring. To evaluate topical zinc oxide for the treatment of warts. This was a randomized, double-blind controlled trial of 44 patients. Twenty-two patients were given topical zinc oxide 20% ointment, and the other 22 received salicylic acid 15% + lactic acid 15% ointment twice daily. All patients were followed up for 3 months or until cure, whichever occurred first. All patients were observed for side-effects. Sixteen patients in the zinc group and 19 in the salicylic acid-lactic acid group completed the study. In the zinc oxide-treated group, 50% of the patients showed complete cure and 18.7% failed to respond, compared with 42% and 26%, respectively, in the salicylic acid-lactic acid-treated group. No patients developed serious side-effects. Topical zinc oxide is an efficacious, painless, and safe therapeutic option for wart treatment.

Heterostructured nanohybrid of zinc oxide-montmorillonite clay.

PubMed

Hur, Su Gil; Kim, Tae Woo; Hwang, Seong-Ju; Hwang, Sung-Ho; Yang, Jae Hun; Choy, Jin-Ho

2006-02-02

We have synthesized heterostructured zinc oxide-aluminosilicate nanohybrids through a hydrothermal reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and the sol solution of zinc acetate. According to X-ray diffraction, N2 adsorption-desorption isotherm, and field emission-scanning electron microscopic analyses, it was found that the intercalation of zinc oxide nanoparticles expands the basal spacing of the host montmorillonite clay, and the crystallites of the nanohybrids are assembled to form a house-of-cards structure. From UV-vis spectroscopic investigation, it becomes certain that calcined nanohybrid contains two kinds of the zinc oxide species in the interlayer space of host lattice and in mesopores formed by the house-of-cards type stacking of the crystallites. Zn K-edge X-ray absorption near-edge structure/extended X-ray absorption fine structure analyses clearly demonstrate that guest species in the nanohybrids exist as nanocrystalline zinc oxides with wurzite-type structure.

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode

DOEpatents

Adler, Thomas C.; McLarnon, Frank R.; Cairns, Elton J.

1994-01-01

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing KOH and a combination of KF and K.sub.2 CO.sub.3 salts which inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics.

Limonia acidissima L. leaf mediated synthesis of zinc oxide nanoparticles: A potent tool against Mycobacterium tuberculosis.

PubMed

Taranath, Tarikere C; Patil, Bheemanagouda N

2016-06-01

The present investigation was undertaken to synthesize zinc oxide nanoparticles using Limonia acidissima L. and to test their efficacy against the growth of Mycobacterium tuberculosis. The formation of zinc oxide nanoparticles was confirmed with UV-visible spectrophotometry. Fourier transform infrared spectroscopy shows the presence of bio-molecules involved in the stabilization of zinc oxide nanoparticles. The shape and size was confirmed with atomic force microscope, X-ray diffraction, and high resolution transmission electron microscope. These nanoparticles were tested for their effect on the growth of M. tuberculosis through the microplate alamar blue assay technique. The UV-visible data reveal that an absorbance peak at 374nm confirms formation of zinc oxide nanoparticles and they are spherical in shape with sizes between 12nm and 53nm. These nanoparticles control the growth of M. tuberculosis at 12.5μg/mL. Phytosynthesis of zinc oxide nanoparticles is a green, eco-friendly technology because it is inexpensive and pollution free. In the present investigation, based on our results we conclude that the aqueous extract of leaves of L. acidissima can be used for the synthesis of zinc oxide nanoparticles. These nanoparticles control the growth of M. tuberculosis and this was confirmed with the microplate alamar blue method. The potential of biogenic zinc oxide nanoparticles may be harnessed as a novel medicine ingredient to combat tuberculosis disease. Copyright © 2016 Asian-African Society for Mycobacteriology. Published by Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-08-15

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

Effect of surface modification and UVA photoactivation on antibacterial bioactivity of zinc oxide powder

NASA Astrophysics Data System (ADS)

Ann, Ling Chuo; Mahmud, Shahrom; Bakhori, Siti Khadijah Mohd; Sirelkhatim, Amna; Mohamad, Dasmawati; Hasan, Habsah; Seeni, Azman; Rahman, Rosliza Abdul

2014-02-01

The effects of surface modification of zinc oxide (ZnO) powder and UVA illumination on the powder towards Escherichia coli and Staphylococcus aureus were investigated. FESEM-EDS results showed that oxygen annealing increased the O:Zn ratio on the surface of ZnO-rod and ZnO-plate samples. Surface conductances of ZnO-rod and ZnO-plate pellets were reduced from 1.05 nS to 0.15 nS and 1.34 nS to 0.23 nS, respectively. Meanwhile, UVA illumination on the surface of the ZnO-rod and ZnO-plate samples was found to improve surface conductance to 7.08 nS and 6.51 nS, respectively, due to the release of charge carrier. Photoluminescence results revealed that oxygen annealing halved the UV emission intensity and green emission intensity, presumably caused by oxygen absorption in the ZnO lattice. The antibacterial results showed that oxygen-treated ZnO exhibited slightly higher growth inhibition on E. coli and S. aureus compared with unannealed ZnO. UVA illumination on ZnO causes the greatest inhibition toward E. coli and S. aureus. Under the UVA excitation, the inhibition of E. coli increased by 18% (ZnO-rod) and 13% (ZnO-plate) while the inhibition of S. aureus increased by 22% (ZnO-rod) and 21% (ZnO-plate). Release of reactive oxygen species were proposed in antibacterial mechanisms, which were aided by surface modification and UVA photoactivation. The reactive oxygen species disrupted the DNA and protein synthesis of the bacterial cell, causing bacteriostatic effects toward E. coli and S. aureus.

ZnO nanoparticle catalysts for use in biodiesel production and method of making

DOEpatents

Yan, Shuli; Salley, Steven O; Ng, K. Y. Simon

2014-11-25

A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system is comprised of a mixture of zinc oxide and a second metal oxide. The zinc oxide includes a mixture of amorphous zinc oxide and zinc oxide nanocrystals, the zinc nanocrystals having a mean grain size between about 20 and 80 nanometers with at least one of the nanocrystals including a mesopore having a diameter of about 5 to 15 nanometers. Preferably, the second metal oxide is a lanthanum oxide, the lanthanum oxide being selected as one from the group of La.sub.2CO.sub.5, LaOOH, and combinations or mixtures thereof.

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR... coloring externally applied drugs. (b) Specifications. Zinc oxide shall conform to the following...

21 CFR 73.2991 - Zinc oxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2991 Zinc oxide. (a) Identity and specifications. The... (a)(1) and (b). (b) Uses and restrictions. Zinc oxide may be safely used in cosmetics, including cosmetics intended for use in the area of the eye, in amounts consistent with good manufacturing practice...

Factors Affecting Oxidation of Thiosalts by Thiobacilli

PubMed Central

Silver, M.; Dinardo, O.

1981-01-01

The effects of temperature, initial pH, and the concentrations of ammonium, phosphate, and heavy metals on the oxidation of thiosalts by an authentic strain of Thiobacillus thiooxidans (ATCC 8085) and by a mixed culture isolated from a base metal-processing mill effluent pond were studied. The optimum temperature was 30°C and the optimum initial pH was 3.75 for both cultures using thiosulfate and for the mixed culture using tetrathionate. T. thiooxidans ATCC 8085 did not oxidize tetrathionate. For a thiosalt concentration of 2,000 ppm (2,000 mg/liter), maximal rates of destruction occurred at concentrations of ammonium ion above 2 mg/liter and in the presence of 1 mg of phosphate per liter. Under optimal conditions, the rate of thiosulfate oxidation by the pure culture was 55 ± 3 mg/liter per h; the mixed culture oxidized thiosulfate at the rate of 40 ± 1 mg/liter per h and tetrathionate at the rate of 50 ± 2 mg/liter per h. Metal ions caused normal inhibition kinetics in the oxidation of thiosulfate by T. thiooxidans ATCC 8085. Ki values were calculated for cadmium (16 mg/liter), copper (0.46 mg/liter), lead (2 mg/liter), silver (3.1 mg/liter), and zinc (33 mg/liter). Only a slight additive effect was apparent in the presence of all of these metal ions. The mixed culture of thiosalt-oxidizing bacteria was less sensitive to heavy metal inhibition; the order of inhibition of thiosulfate oxidation was Cd < Zn < Pb < Ag < Cu, and that of tetrathionate oxidation was Zn < Cd < Pb < Ag < Cu. PMID:16345785

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

PubMed

Ramimoghadam, Donya; Bin Hussein, Mohd Zobir; Taufiq-Yap, Yun Hin

2013-01-01

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. 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. 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.

Size-dependent bacterial growth inhibition and mechanism of antibacterial activity of zinc oxide nanoparticles.

PubMed

Raghupathi, Krishna R; Koodali, Ranjit T; Manna, Adhar C

2011-04-05

The antibacterial properties of zinc oxide nanoparticles were investigated using both gram-positive and gram-negative microorganisms. These studies demonstrate that ZnO nanoparticles have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. The antibacterial activity of the ZnO nanoparticles was inversely proportional to the size of the nanoparticles in S. aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Northern analyses of various reactive oxygen species (ROS) specific genes and confocal microscopy suggest that the antibacterial activity of ZnO nanoparticles might involve both the production of reactive oxygen species and the accumulation of nanoparticles in the cytoplasm or on the outer membranes. Overall, the experimental results suggest that ZnO nanoparticles could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections.

Toxicity mechanism of titanium dioxide and zinc oxide nanoparticles against food pathogens.

PubMed

Venkatasubbu, G Devanand; Baskar, R; Anusuya, T; Seshan, C Arun; Chelliah, Ramachandran

2016-12-01

Food preservation is an important field of research. It extends the shelf life of major food products. Our current study is based on food preservation through TiO 2 and ZnO nanoparticles. TiO 2 and ZnO are biocompatible nanomaterial. The biocompatibility of the materials were established through toxicity studies on cell lines. Titanium dioxide and Zinc Oxide nanoparticle were synthesized by wet chemical process. They are characterized by X-Ray diffraction and TEM. The antibacterial activities of both the materials were analysed to ensure their effectiveness as food preservative against Salmonella typhi, Klebsiella pneumoniae and Shigella flexneri. The results indicates that TiO 2 and ZnO nanoparticle inhibits Salmonella, Klebsiella and Shigella. The mode of action is by the generation of ROS in cases of Salmonella, Klebsiella. Mode of action in Shigella is still unclear. It was also proved that TiO 2 and ZnO nanoparticle are biocompatible materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Zinc disrupts central carbon metabolism and capsule biosynthesis in Streptococcus pyogenes.

PubMed

Ong, Cheryl-lynn Y; Walker, Mark J; McEwan, Alastair G

2015-06-01

Neutrophils release free zinc to eliminate the phagocytosed bacterial pathogen Streptococcus pyogenes (Group A Streptococcus; GAS). In this study, we investigated the mechanisms underpinning zinc toxicity towards this human pathogen, responsible for diseases ranging from pharyngitis and impetigo, to severe invasive infections. Using the globally-disseminated M1T1 GAS strain, we demonstrate that zinc stress impairs glucose metabolism through the inhibition of the glycolytic enzymes phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase. In the presence of zinc, a metabolic shift to the tagatose-6-phosphate pathway allows conversion of D-galactose to dihydroxyacetone phosphate and glyceraldehyde phosphate, partially bypassing impaired glycolytic enzymes to generate pyruvate. Additionally, zinc inhibition of phosphoglucomutase results in decreased capsule biosynthesis. These data indicate that zinc exerts it toxicity via mechanisms that inhibit both GAS central carbon metabolism and virulence pathways.

Zinc disrupts central carbon metabolism and capsule biosynthesis in Streptococcus pyogenes

PubMed Central

Ong, Cheryl-lynn Y.; Walker, Mark J.; McEwan, Alastair G.

2015-01-01

Neutrophils release free zinc to eliminate the phagocytosed bacterial pathogen Streptococcus pyogenes (Group A Streptococcus; GAS). In this study, we investigated the mechanisms underpinning zinc toxicity towards this human pathogen, responsible for diseases ranging from pharyngitis and impetigo, to severe invasive infections. Using the globally-disseminated M1T1 GAS strain, we demonstrate that zinc stress impairs glucose metabolism through the inhibition of the glycolytic enzymes phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase. In the presence of zinc, a metabolic shift to the tagatose-6-phosphate pathway allows conversion of D-galactose to dihydroxyacetone phosphate and glyceraldehyde phosphate, partially bypassing impaired glycolytic enzymes to generate pyruvate. Additionally, zinc inhibition of phosphoglucomutase results in decreased capsule biosynthesis. These data indicate that zinc exerts it toxicity via mechanisms that inhibit both GAS central carbon metabolism and virulence pathways. PMID:26028191

Comparative studies on acid leaching of zinc waste materials

NASA Astrophysics Data System (ADS)

Rudnik, Ewa; Włoch, Grzegorz; Szatan, Leszek

2017-11-01

Three industrial waste materials were characterized in terms of their elemental and phase compositions, leaching behaviour in 10% sulfuric acid solution as well as leaching thermal effects. Slag from melting of mixed metallic scrap contained about 50% Zn and 10% Pb. It consisted mainly of various oxides and oxy-chlorides of metals. Zinc spray metallizing dust contained about 77% Zn in form of zinc and/or zinc-iron oxides, zinc metal and Zn-Fe intermetallic. Zinc ash from hot dip galvanizing was a mixture of zinc oxide, metallic zinc and zinc hydroxide chloride and contained about 80% Zn. Dissolution efficiency of zinc from the first material was 80% (independently on the solid to liquid ratio, 50-150 kg/m3), while decrease of the efficacy from 80% to 60% with increased solid to liquid ratio for the two remaining materials was observed. Both increase in the temperature (20 °C to 35 °C) and agitation rate (300 rpm to 900 rpm) did not improve seriously the leaching results. In all cases, transfer of zinc ions to the leachate was accompanied by different levels of solution contamination, depending on the type of the waste. Leaching of the materials was exothermic with the similar reaction heats for two high oxide-type products (slag, zinc ash) and higher values for the spray metallizing dust.

Zinc Deprivation Mediates Alcohol-Induced Hepatocyte IL-8 Analog Expression in Rodents via an Epigenetic Mechanism

PubMed Central

Zhao, Yantao; Zhong, Wei; Sun, Xiuhua; Song, Zhenyuan; Clemens, Dahn L.; Kang, Y. James; McClain, Craig J.; Zhou, Zhanxiang

2011-01-01

Neutrophil infiltration caused by IL-8 production is a central mechanism in alcohol-induced hepatitis. This study was performed to examine if an epigenetic mechanism is involved in alcohol-induced IL-8 production. Mice were pair-fed an alcohol-containing liquid diet for 4 weeks. Alcohol exposure induced hepatitis as indicated by increased expression of keratinocyte-derived cytokine (mouse IL-8) and neutrophil infiltration. Alcohol exposure induced histone 3 hyperacetylation owing to inhibition of histone deacetylase (HDAC) in association with NF-κB activation. Cell culture studies showed that alcohol exposure induced IL-8 and cytokine-induced neutrophil chemoattractant-1 (CINC-1, rat IL-8) production in human VL-17A cells and rat H4IIEC3 cells, respectively, dependent on acetaldehyde production, oxidative stress, and zinc release. Zinc deprivation alone induced CINC-1 production and acted synergistically with lipopolysaccharide or tumor necrosis factor-α on CINC-1 production. Zinc deprivation induced histone 3 hyperacetylation at lysine 9 through suppression of HDAC activity. Zinc deprivation caused nuclear translocation of NF-κB, and reduced HDAC binding to NF-κB. Chromatin immunoprecipitation (ChIP) showed that zinc deprivation caused histone 3 hyperacetylation as well as increased NF-κB binding to the CINC-1 promoter. In conclusion, inactivation of HDAC caused by zinc deprivation is a novel mechanism underlying IL-8 up-regulation in alcoholic hepatitis. PMID:21708112

Neutral endopeptidase knockout induces hyperalgesia in a model of visceral pain, an effect related to bradykinin and nitric oxide.

PubMed

Fischer, Hanspeter S; Zernig, Gerald; Hauser, Kurt F; Gerard, Craig; Hersh, Louis B; Saria, Alois

2002-01-01

Neutral endopeptidase (EC3.4.24.11, NEP, enkephalinase) is a zinc-metalloendopeptidase, cleaving a variety of substrates like enkephalins, substance P, and bradykinin. In the brain, NEP is a key enzyme in the degradation of enkephalins. Pharmacological inhibition of NEP-activity causes analgesia resulting from enhanced extracellular enkephalin concentrations. Recently, transgenic mice lacking the enzyme NEP have been developed (Lu, 1995). The present study was designed to investigate the nociceptive behavior of these NEP-knockout mice. Interestingly, NEP-deficient mice did not respond with decreased pain perception, but exhibited hyperalgesia in the hot-plate jump, warm-water tail-withdrawal, and mostnotablyin theacetic-acid writhing test. Inhibition of aminopeptidase N by bestatin reduced writhing in both strains, whereas NEP-inhibition by thiorphan reduced writhing selectively in wild-type mice. Naloxone increased writhing in wild-type but not in knockouts, whereas the bradykinin B2-receptor antagonist HOE140 reduced writhing selectively in NEP-knockouts. Similarly, the nitric oxide synthase inhibitor L-NAME reduced writhing in NEP-knockouts. These results indicate that genetic elimination of NEP, in contrast to pharmacological inhibition, leads to bradykinin-induced hyperalgesia instead of enkephalin-mediated analgesia. Nitric oxide (NO) is suggested to be involved in this process.

The development of latent fingerprints by zinc oxide and tin oxide nanoparticles prepared by precipitation technique

NASA Astrophysics Data System (ADS)

Luthra, Deepali; Kumar, Sacheen

2018-05-01

Fingerprints are the very important evidence at the crime scene which must be developed clearly with shortest duration of time to solve the case. Metal oxide nanoparticles could be the mean to develop the latent fingerprints. Zinc oxide and Tin Oxide Nanoparticles were prepared by using chemical precipitation technique which were dried and characterized by X-ray diffraction, UV-Visible spectroscopy and FTIR. The size of zinc oxide crystallite was found to be 14.75 nm with minimum reflectance at 360 nm whereas tin oxide have the size of 90 nm and reflectance at minimum level 321 nm. By using these powdered samples on glass, plastic and glossy cardboard, latent fingerprints were developed. Zinc oxide was found to be better candidate than tin oxide for the fingerprint development on all the three types of substrates.

Cadmium-free junction fabrication process for CuInSe.sub.2 thin film solar cells

DOEpatents

Ramanathan, Kannan V.; Contreras, Miguel A.; Bhattacharya, Raghu N.; Keane, James; Noufi, Rommel

1999-01-01

The present invention provides an economical, simple, dry and controllable semiconductor layer junction forming process to make cadmium free high efficiency photovoltaic cells having a first layer comprised primarily of copper indium diselenide having a thin doped copper indium diselenide n-type region, generated by thermal diffusion with a group II(b) element such as zinc, and a halide, such as chlorine, and a second layer comprised of a conventional zinc oxide bilayer. A photovoltaic device according the present invention includes a first thin film layer of semiconductor material formed primarily from copper indium diselenide. Doping of the copper indium diselenide with zinc chloride is accomplished using either a zinc chloride solution or a solid zinc chloride material. Thermal diffusion of zinc chloride into the copper indium diselenide upper region creates the thin n-type copper indium diselenide surface. A second thin film layer of semiconductor material comprising zinc oxide is then applied in two layers. The first layer comprises a thin layer of high resistivity zinc oxide. The second relatively thick layer of zinc oxide is doped to exhibit low resistivity.

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 FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR... color additive zinc oxide shall conform in identity and specifications to the requirements of § 73.1991...

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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product...

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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8991 Zinc oxide. (a) Product...

Zinc oxide nanorod clusters deposited seaweed cellulose sheet for antimicrobial activity.

PubMed

Bhutiya, Priyank L; Mahajan, Mayur S; Abdul Rasheed, M; Pandey, Manoj; Zaheer Hasan, S; Misra, Nirendra

2018-06-01

Seaweed cellulose was isolated from green seaweed Ulva fasciata using a common bleaching agent. Sheet containing porous mesh was prepared from the extracted seaweed crystalline cellulose along with zinc oxide (ZnO) nanorod clusters grown over the sheet by single step hydrothermal method. Seaweed cellulose and zinc oxide nanorod clusters deposited seaweed cellulose sheet was characterized by FT-IR, XRD, TGA, and SEM-EDX. Morphology showed that the diameter of zinc oxide nanorods were around 70nm. Zinc oxide nanorod clusters deposited on seaweed cellulose sheet gave remarkable antibacterial activity towards gram-positive (Staphylococcus aureus, Bacillus ceresus, Streptococcus thermophilis) and gram-negative (Escherichia coli, Pseudomonas aeruginous) microbes. Such deposited sheet has potential applications in pharmaceutical, biomedical, food packaging, water treatment and biotechnological industries. Copyright © 2018 Elsevier B.V. All rights reserved.

Electron spectroscopy imaging and surface defect configuration of zinc oxide nanostructures under different annealing ambient

NASA Astrophysics Data System (ADS)

Ann, Ling Chuo; Mahmud, Shahrom; Bakhori, Siti Khadijah Mohd

2013-01-01

In this study, electron spectroscopy imaging was used to visualize the elemental distribution of zinc oxide nanopowder. Surface modification in zinc oxide was done through annealing treatment and type of surface defect was also inferred from the electron spectroscopy imaging investigation. The micrographs revealed the non-stoichiometric distribution of the elements in the unannealed samples. Annealing the samples in nitrogen and oxygen ambient at 700 °C would alter the density of the elements in the samples as a result of removal or absorption of oxygen. The electrical measurement showed that nitrogen annealing treatment improved surface electrical conductivity, whereas oxygen treatment showed an adverse effect. Observed change in the photoluminescence green emission suggested that oxygen vacancies play a significant role as surface defects. Structural investigation carried out through X-ray diffraction revealed the polycrystalline nature of both zinc oxide samples with hexagonal phase whereby annealing process increased the crystallinity of both zinc oxide specimens. Due to the different morphologies of the two types of zinc oxide nanopowders, X-ray diffraction results showed different stress levels in their structures and the annealing treatment give significant effect to the structural stress. Electron spectroscopy imaging was a useful technique to identify the elemental distribution as well as oxygen defect in zinc oxide nanopowder.

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.

Formation of ZnO at zinc oxidation by near- and supercritical water under the constant electric field

NASA Astrophysics Data System (ADS)

Shishkin, A. V.; Sokol, M. Ya.; Shatrova, A. V.; Fedyaeva, O. N.; Vostrikov, A. A.

2014-12-01

The work has detected an influence of a constant electric field (up to E = 300 kV/m) on the structure of a nanocrystalline layer of zinc oxide, formed on the surface of a planar zinc anode in water under supercritical (673 K and 23 MPa) and near-critical (673 K and 17. 5 MPa) conditions. The effect of an increase of zinc oxidation rate with an increase in E is observed under supercritical conditions and is absent at near-critical ones. Increase in the field strength leads to the formation of a looser structure in the inner part of the zinc oxide layer.

Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into intact and tape-stripped human skin

NASA Astrophysics Data System (ADS)

Szikszai, Z.; Kertész, Zs.; Bodnár, E.; Major, I.; Borbíró, I.; Kiss, Á. Z.; Hunyadi, J.

2010-06-01

Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the small particle size makes the product more transparent compared to formulations containing coarser particles. In the present work the penetration of ultrafine zinc oxide into intact and tape-stripped human skin was investigated using nuclear microprobe techniques, such as proton induced X-ray spectroscopy and scanning transmission ion microscopy. Our results indicate that the penetration of ultrafine zinc oxide, in a hydrophobic basis gel with 48 h application time, is limited to the stratum corneum layer of the intact skin. Removing the stratum corneum partially or entirely by tape-stripping did not cause the penetration of the particles into the deeper dermal layers; the zinc particles remained on the surface of the skin.

Two mechanisms of oral malodor inhibition by zinc ions.

PubMed

Suzuki, Nao; Nakano, Yoshio; Watanabe, Takeshi; Yoneda, Masahiro; Hirofuji, Takao; Hanioka, Takashi

2018-01-18

The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria.

Two mechanisms of oral malodor inhibition by zinc ions

PubMed Central

Suzuki, Nao; Nakano, Yoshio; Watanabe, Takeshi; Yoneda, Masahiro; Hirofuji, Takao; Hanioka, Takashi

2018-01-01

Abstract Objectives The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. Material and Methods The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Results Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Conclusions Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria. PMID:29364345

Method for the regeneration of spent molten zinc chloride

DOEpatents

Zielke, Clyde W.; Rosenhoover, William A.

1981-01-01

In a process for regenerating spent molten zinc chloride which has been used in the hydrocracking of coal or ash-containing polynuclear aromatic hydrocarbonaceous materials derived therefrom and which contains zinc chloride, zinc oxide, zinc oxide complexes and ash-containing carbonaceous residue, by incinerating the spent molten zinc chloride to vaporize the zinc chloride for subsequent condensation to produce a purified molten zinc chloride: an improvement comprising the use of clay in the incineration zone to suppress the vaporization of metals other than zinc. Optionally water is used in conjunction with the clay to further suppress the vaporization of metals other than zinc.

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode

DOEpatents

Adler, T.C.; McLarnon, F.R.; Cairns, E.J.

1994-04-12

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing KOH and a combination of KF and K[sub 2]CO[sub 3] salts which inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics. 8 figures.

Inhibition of poly(ADP-ribose)polymerase-1 and DNA repair by uranium

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

Cooper, Karen L.; Dashner, Erica J.; Tsosie, Ranalda

Uranium has radiological and non-radiological effects within biological systems and there is increasing evidence for genotoxic and carcinogenic properties attributable to uranium through its heavy metal properties. In this study, we report that low concentrations of uranium (as uranyl acetate; < 10 μM) is not cytotoxic to human embryonic kidney cells or normal human keratinocytes; however, uranium exacerbates DNA damage and cytotoxicity induced by hydrogen peroxide, suggesting that uranium may inhibit DNA repair processes. Concentrations of uranyl acetate in the low micromolar range inhibited the zinc finger DNA repair protein poly(ADP-ribose) polymerase (PARP)-1 and caused zinc loss from PARP-1 protein.more » Uranyl acetate exposure also led to zinc loss from the zinc finger DNA repair proteins Xeroderma Pigmentosum, Complementation Group A (XPA) and aprataxin (APTX). In keeping with the observed inhibition of zinc finger function of DNA repair proteins, exposure to uranyl acetate enhanced retention of induced DNA damage. Co-incubation of uranyl acetate with zinc largely overcame the impact of uranium on PARP-1 activity and DNA damage. These findings present evidence that low concentrations of uranium can inhibit DNA repair through disruption of zinc finger domains of specific target DNA repair proteins. This may provide a mechanistic basis to account for the published observations that uranium exposure is associated with DNA repair deficiency in exposed human populations. - Highlights: • Low micromolar concentration of uranium inhibits polymerase-1 (PARP-1) activity. • Uranium causes zinc loss from multiple DNA repair proteins. • Uranium enhances retention of DNA damage caused by ultraviolet radiation. • Zinc reverses the effects of uranium on PARP activity and DNA damage repair.« less

Silicon (Si) alleviates cotton (Gossypium hirsutum L.) from zinc (Zn) toxicity stress by limiting Zn uptake and oxidative damage.

PubMed

Anwaar, Shad Ali; Ali, Shafaqat; Ali, Skhawat; Ishaque, Wajid; Farid, Mujahid; Farooq, Muhammad Ahsan; Najeeb, Ullah; Abbas, Farhat; Sharif, Muhammad

2015-03-01

Silicon (Si) is as an important fertilizer element, which has been found effective in enhancing plant tolerance to variety of biotic and a-biotic stresses. This study investigates the Si potential to alleviate zinc (Zn) toxicity stress in cotton (Gossypium hirsutum L.). Cotton plants were grown in hydroponics and exposed to different Zn concentration, 0, 25, and 50 μM, alone and/or in combination with 1 mM Si. Incremental Zn concentration in growth media instigated the cellular oxidative damage that was evident from elevated levels of hydrogen peroxide (H2O2), electrolyte leakage, and malondialdehyde (MDA) and consequently inhibited cotton growth, biomass, chlorophyll pigments, and photosynthetic process. Application of Si significantly suppressed Zn accumulation in various plant parts, i.e., roots, stems, and leaves and thus promoted biomass, photosynthetic, growth parameters, and antioxidant enzymes activity of Zn-stressed as well unstressed plants. In addition, Si reduced the MDA and H2O2 production and electrolyte leakage suggesting its role in protecting cotton plants from Zn toxicity-induced oxidative damage. Thus, the study indicated that exogenous Si application could improve growth and development of cotton crop experiencing Zn toxicity stress by limiting Zn bioavailability and oxidative damage.

Modulation of extrasynaptic NMDA receptors by synaptic and tonic zinc.

PubMed

Anderson, Charles T; Radford, Robert J; Zastrow, Melissa L; Zhang, Daniel Y; Apfel, Ulf-Peter; Lippard, Stephen J; Tzounopoulos, Thanos

2015-05-19

Many excitatory synapses contain high levels of mobile zinc within glutamatergic vesicles. Although synaptic zinc and glutamate are coreleased, it is controversial whether zinc diffuses away from the release site or whether it remains bound to presynaptic membranes or proteins after its release. To study zinc transmission and quantify zinc levels, we required a high-affinity rapid zinc chelator as well as an extracellular ratiometric fluorescent zinc sensor. We demonstrate that tricine, considered a preferred chelator for studying the role of synaptic zinc, is unable to efficiently prevent zinc from binding low-nanomolar zinc-binding sites, such as the high-affinity zinc-binding site found in NMDA receptors (NMDARs). Here, we used ZX1, which has a 1 nM zinc dissociation constant and second-order rate constant for binding zinc that is 200-fold higher than those for tricine and CaEDTA. We find that synaptic zinc is phasically released during action potentials. In response to short trains of presynaptic stimulation, synaptic zinc diffuses beyond the synaptic cleft where it inhibits extrasynaptic NMDARs. During higher rates of presynaptic stimulation, released glutamate activates additional extrasynaptic NMDARs that are not reached by synaptically released zinc, but which are inhibited by ambient, tonic levels of nonsynaptic zinc. By performing a ratiometric evaluation of extracellular zinc levels in the dorsal cochlear nucleus, we determined the tonic zinc levels to be low nanomolar. These results demonstrate a physiological role for endogenous synaptic as well as tonic zinc in inhibiting extrasynaptic NMDARs and thereby fine tuning neuronal excitability and signaling.

Modulation of extrasynaptic NMDA receptors by synaptic and tonic zinc

PubMed Central

Anderson, Charles T.; Radford, Robert J.; Zastrow, Melissa L.; Zhang, Daniel Y.; Apfel, Ulf-Peter; Lippard, Stephen J.; Tzounopoulos, Thanos

2015-01-01

Many excitatory synapses contain high levels of mobile zinc within glutamatergic vesicles. Although synaptic zinc and glutamate are coreleased, it is controversial whether zinc diffuses away from the release site or whether it remains bound to presynaptic membranes or proteins after its release. To study zinc transmission and quantify zinc levels, we required a high-affinity rapid zinc chelator as well as an extracellular ratiometric fluorescent zinc sensor. We demonstrate that tricine, considered a preferred chelator for studying the role of synaptic zinc, is unable to efficiently prevent zinc from binding low-nanomolar zinc-binding sites, such as the high-affinity zinc-binding site found in NMDA receptors (NMDARs). Here, we used ZX1, which has a 1 nM zinc dissociation constant and second-order rate constant for binding zinc that is 200-fold higher than those for tricine and CaEDTA. We find that synaptic zinc is phasically released during action potentials. In response to short trains of presynaptic stimulation, synaptic zinc diffuses beyond the synaptic cleft where it inhibits extrasynaptic NMDARs. During higher rates of presynaptic stimulation, released glutamate activates additional extrasynaptic NMDARs that are not reached by synaptically released zinc, but which are inhibited by ambient, tonic levels of nonsynaptic zinc. By performing a ratiometric evaluation of extracellular zinc levels in the dorsal cochlear nucleus, we determined the tonic zinc levels to be low nanomolar. These results demonstrate a physiological role for endogenous synaptic as well as tonic zinc in inhibiting extrasynaptic NMDARs and thereby fine tuning neuronal excitability and signaling. PMID:25947151

OP-AMPS on Flexible Substrates with Printable Materials

DTIC Science & Technology

2011-08-10

Zinc Tin Oxide Thin - Film - Transistor Enhancement...II196, 2010. [3] D. Geng, D. H. Kang, and J. Jang, "High-Performance Amorphous Indium-Gallium- Zinc - Oxide Thin - Film Transistor With a Self-Aligned...B., Dodabalapur, A., “Band transport and mobility edge in amorphous solution-processed zinc tin oxide thin - film transistors ”, Applied

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...

Structure Guided Chemical Modifications of Propylthiouracil Reveal Novel Small Molecule Inhibitors of Cytochrome b5 Reductase 3 That Increase Nitric Oxide Bioavailability*

PubMed Central

Rahaman, Md. Mizanur; Reinders, Fabio G.; Koes, David; Nguyen, Anh T.; Mutchler, Stephanie M.; Sparacino-Watkins, Courtney; Alvarez, Roger A.; Miller, Megan P.; Cheng, Dongmei; Chen, Bill B.; Jackson, Edwin K.; Camacho, Carlos J.; Straub, Adam C.

2015-01-01

NADH cytochrome b5 reductase 3 (CYB5R3) is critical for reductive reactions such as fatty acid elongation, cholesterol biosynthesis, drug metabolism, and methemoglobin reduction. Although the physiological and metabolic importance of CYB5R3 has been established in hepatocytes and erythrocytes, emerging investigations suggest that CYB5R3 is critical for nitric oxide signaling and vascular function. However, advancement toward fully understanding CYB5R3 function has been limited due to a lack of potent small molecule inhibitors. Because of this restriction, we modeled the binding mode of propylthiouracil, a weak inhibitor of CYB5R3 (IC50 = ∼275 μm), and used it as a guide to predict thiouracil-biased inhibitors from the set of commercially available compounds in the ZINC database. Using this approach, we validated two new potent derivatives of propylthiouracil, ZINC05626394 (IC50 = 10.81 μm) and ZINC39395747 (IC50 = 9.14 μm), both of which inhibit CYB5R3 activity in cultured cells. Moreover, we found that ZINC39395747 significantly increased NO bioavailability in renal vascular cells, augmented renal blood flow, and decreased systemic blood pressure in response to vasoconstrictors in spontaneously hypertensive rats. These compounds will serve as a new tool to examine the biological functions of CYB5R3 in physiology and disease and also as a platform for new drug development. PMID:26001785

Oxidation and Condensation of Zinc Fume From Zn-CO 2-CO-H 2O Streams Relevant to Steelmaking Off-Gas Systems

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

Bronson, Tyler Mark; Ma, Naiyang; Zhu, Liang Zhu

Here the objective of this research was to study the condensation of zinc vapor to metallic zinc and zinc oxide solid under varying environments to investigate the feasibility of in-process separation of zinc from steelmaking off-gas dusts. Water vapor content, temperature, degree of cooling, gas composition, and initial zinc partial pressure were varied to simulate the possible conditions that can occur within steelmaking off-gas systems, limited to Zn-CO 2-CO-H 2O gas compositions. The temperature of deposition and the effect of rapidly quenching the gas were specifically studied. A homogeneous nucleation model for applicable experiments was applied to the analysis of the experimental data. It was determined that under the experimental conditions, oxidation of zinc vapor by H 2O or CO 2 does not occur above 1108 K (835 °C) even for highly oxidizing streams (CO 2/CO = 40/7). Rate expressions that correlate CO 2 and H 2O oxidation rates to gas composition, partial pressure of water vapor, temperature, and zinc partial pressure were determined to be as follows: Ratemore » $$ \\left(\\frac{mol}{m^2s}\\right) $$ = 406 exp $$ \\left(\\frac{-50.2 kJ/mol}{RT}\\right) $$ (pZnpCO 2 $-$ PCO/K eqCO 2) $$\\frac{mol}{m^2 x s}$$ Rate $$ \\left(\\frac{mol}{m^2s}\\right) $$ = 32.9 exp $$ \\left(\\frac{-13.7 kJ/mol}{RT}\\right) $$ (pZnPH 2O $-$ PH 2/K eqH 2O) $$\\frac{mol}{m^2 x s}$$. It was proven that a rapid cooling rate (500 K/s) significantly increases the ratio of metallic zinc to zinc oxide as opposed to a slow cooling rate (250 K/s). SEM analysis found evidence of heterogeneous growth of ZnO as well as of homogeneous formation of metallic zinc. The homogeneous nucleation model fit well with experiments where only metallic zinc deposited. An expanded model with rates of oxidation by CO 2 and H 2O as shown was combined with the homogenous nucleation model and then compared with experimental data. The calculated results based on the model gave a reasonable fit to the measured data. For the conditions used in this study, the rate equations for the oxidation of zinc by carbon dioxide and water vapor as well as the homogeneous nucleation model of metallic zinc were applicable for various temperatures, zinc partial pressures, CO 2:CO ratios, and H 2O partial pressures.« less

Oxidation and Condensation of Zinc Fume From Zn-CO 2-CO-H 2O Streams Relevant to Steelmaking Off-Gas Systems

DOE PAGES

Bronson, Tyler Mark; Ma, Naiyang; Zhu, Liang Zhu; ...

2017-01-23

Here the objective of this research was to study the condensation of zinc vapor to metallic zinc and zinc oxide solid under varying environments to investigate the feasibility of in-process separation of zinc from steelmaking off-gas dusts. Water vapor content, temperature, degree of cooling, gas composition, and initial zinc partial pressure were varied to simulate the possible conditions that can occur within steelmaking off-gas systems, limited to Zn-CO 2-CO-H 2O gas compositions. The temperature of deposition and the effect of rapidly quenching the gas were specifically studied. A homogeneous nucleation model for applicable experiments was applied to the analysis of the experimental data. It was determined that under the experimental conditions, oxidation of zinc vapor by H 2O or CO 2 does not occur above 1108 K (835 °C) even for highly oxidizing streams (CO 2/CO = 40/7). Rate expressions that correlate CO 2 and H 2O oxidation rates to gas composition, partial pressure of water vapor, temperature, and zinc partial pressure were determined to be as follows: Ratemore » $$ \\left(\\frac{mol}{m^2s}\\right) $$ = 406 exp $$ \\left(\\frac{-50.2 kJ/mol}{RT}\\right) $$ (pZnpCO 2 $-$ PCO/K eqCO 2) $$\\frac{mol}{m^2 x s}$$ Rate $$ \\left(\\frac{mol}{m^2s}\\right) $$ = 32.9 exp $$ \\left(\\frac{-13.7 kJ/mol}{RT}\\right) $$ (pZnPH 2O $-$ PH 2/K eqH 2O) $$\\frac{mol}{m^2 x s}$$. It was proven that a rapid cooling rate (500 K/s) significantly increases the ratio of metallic zinc to zinc oxide as opposed to a slow cooling rate (250 K/s). SEM analysis found evidence of heterogeneous growth of ZnO as well as of homogeneous formation of metallic zinc. The homogeneous nucleation model fit well with experiments where only metallic zinc deposited. An expanded model with rates of oxidation by CO 2 and H 2O as shown was combined with the homogenous nucleation model and then compared with experimental data. The calculated results based on the model gave a reasonable fit to the measured data. For the conditions used in this study, the rate equations for the oxidation of zinc by carbon dioxide and water vapor as well as the homogeneous nucleation model of metallic zinc were applicable for various temperatures, zinc partial pressures, CO 2:CO ratios, and H 2O partial pressures.« less

Lead inhibition of DNA-binding mechanism of Cys(2)His(2) zinc finger proteins.

PubMed

Hanas, J S; Rodgers, J S; Bantle, J A; Cheng, Y G

1999-11-01

The association of lead with chromatin in cells suggests that deleterious metal effects may in part be mediated through alterations in gene function. To elucidate if and how lead may alter DNA binding of cysteine-rich zinc finger proteins, lead ions were analyzed for their ability to alter the DNA binding mechanism of the Cys(2)His(2) zinc finger protein transcription factor IIIA (TFIIIA). As assayed by DNase I protection, the interaction of TFIIIA with the 50-bp internal control region of the 5S ribosomal gene was partially inhibited by 5 microM lead ions and completely inhibited by 10 to 20 microM lead ions. Preincubation of free TFIIIA with lead resulted in DNA-binding inhibition, whereas preincubation of a TFIIIA/5S RNA complex with lead did not result in DNA-binding inhibition. Because 5S RNA binds TFIIIA zinc fingers, this result is consistent with an inhibition mechanism via lead binding to zinc fingers. The complete loss of DNase I protection on the 5S gene indicates the mechanism of inhibition minimally involves the N-terminal fingers of TFIIIA. Inhibition was not readily reversible and occurred in the presence of an excess of beta-mercaptoethanol. Inhibition kinetics were fast, progressing to completion in approximately 5 min. Millimolar concentrations of sulfhydryl-specific arsenic ions were not inhibitory for TFIIIA binding. Micromolar concentrations of lead inhibited DNA binding by Sp1, another Cys(2)His(2) finger protein, but not by the nonfinger protein AP2. Inhibition of Cys(2)His(2) zinc finger transcription factors by lead ions at concentrations near those known to have deleterious physiological effects points to new molecular mechanisms for lead toxicity in promoting disease.

Green synthesis and characterization of zinc oxide nanoparticle using insulin plant (Costus pictus D. Don) and investigation of its antimicrobial as well as anticancer activities

NASA Astrophysics Data System (ADS)

Suresh, Joghee; Pradheesh, Ganeshan; Alexramani, Vincent; Sundrarajan, Mahalingam; Hong, Sun Ig

2018-03-01

In this work we aim to synthesize biocompatible ZnO nanoparticles from the zinc nitrate via green process using leaf extracts of the Costus pictus D. Don medicinal plant. FTIR studies confirm the presence of biomolecules and metal oxides. X-ray diffraction (XRD) structural analysis reveals the formation of pure hexagonal phase structures of ZnO nanoparticles. The surface morphologies of ZnO nanoparticles observed under a scanning electron microscope (SEM) suggest that most ZnO crystallites are hexagonal. EDX analysis confirms the presence of primarily zinc and oxygen. TEM images show that biosynthesized zinc oxide nanoparticles are hexagonal and spherical. The plausible formation mechanisms of zinc oxide nanoparticles are also predicted. The biosynthesized zinc oxide nanoparticles exhibit strong antimicrobial behavior against bacterial and fungal species when employing the agar diffusion method. Synthesized ZnO nanoparticles exhibit anticancer activity against Daltons lymphoma ascites (DLA) cells as well as antimicrobial activity against some bacterial and fungal strains.

Directed spatial organization of zinc oxide nanostructures

DOEpatents

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

2009-02-17

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

Study of physical properties of metal oxide nanoparticles obtained in acoustoplasma discharge

NASA Astrophysics Data System (ADS)

Bulychev, N. A.; Kazaryan, M. A.; Zakharyan, A. R.; Bodryshev, V. V.; Kirichenko, M. N.; Shevchenko, S. N.; Yakunin, V. G.; Timoshenko, V. Y.; Bychenko, A. B.

2018-04-01

Nanoparticles of tungsten, copper, iron, and zinc oxides were synthesized in acoustoplasma discharge. Their size distribution was studied by electron microscopy and laser correlation spectroscopy. Ultrasound was found to narrow significantly the size distribution width of zinc oxide nanoparticles. Water suspensions of zinc oxide nanoparticles showed photoluminescence in red and near infrared spectral ranges, which makes them a promising material for luminescent diagnostics of biological systems.

The route of liquid precursor to ZnO nanoparticles in premixed combustion spray pyrolysis

NASA Astrophysics Data System (ADS)

Widiyastuti, W.; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

2018-04-01

Zinc oxide nanoparticles had been successfully synthesized by premixed combustion spray pyrolysis. Zinc acetate was dissolved in distilled water was selected as a liquid precursor. Zinc nitrate was also used for comparison the effect of precursor type on the generated particles morphology and the crystallinity. The premixed combustion reaction used liquefied petroleum gas (LPG) mainly consisting of butane and propane as a fuel and compressed air used as an oxidizer. The liquid precursor was atomized using a custom two fluid nozzle to generate droplets. Then, the droplets were sprayed by the flow of air as a carrier gas into the premixed combustion reactor. The zinc precursor was decomposed to zinc oxide due to the high temperature as a result of combustion reaction inside the reactor resulting in nanoparticles formation. The particle size decreased with the increase of the fuel flow rate. In addition, it can be found that at the same flow rate of fuel, the particle size of zinc oxide synthesized using zinc nitrate is larger than that of the use of zinc acetate as a precursor.

Low-temperature solution-processed zinc oxide field effect transistor by blending zinc hydroxide and zinc oxide nanoparticle in aqueous solutions

NASA Astrophysics Data System (ADS)

Shin, Hyeonwoo; Kang, Chan-mo; Baek, Kyu-Ha; Kim, Jun Young; Do, Lee-Mi; Lee, Changhee

2018-05-01

We present a novel methods of fabricating low-temperature (180 °C), solution-processed zinc oxide (ZnO) transistors using a ZnO precursor that is blended with zinc hydroxide [Zn(OH)2] and zinc oxide hydrate (ZnO • H2O) in an ammonium solution. By using the proposed method, we successfully improved the electrical performance of the transistor in terms of the mobility (μ), on/off current ratio (I on/I off), sub-threshold swing (SS), and operational stability. Our new approach to forming a ZnO film was systematically compared with previously proposed methods. An atomic forced microscopic (AFM) image and an X-ray photoelectron spectroscopy (XPS) analysis showed that our method increases the ZnO crystallite size with less OH‑ impurities. Thus, we attribute the improved electrical performance to the better ZnO film formation using the blending methods.

Microwave synthesis of ZnO@mSiO₂ for detailed antifungal mode of action study: understanding the insights into oxidative stress.

PubMed

Mitra, Shouvik; Patra, Prasun; Pradhan, Saheli; Debnath, Nitai; Dey, Kushal Kumar; Sarkar, Sampad; Chattopadhyay, Dhrubajyoti; Goswami, Arunava

2015-04-15

A simple chemical method has been devised for deliberate incorporation of zinc oxide nanoparticles (ZNPs) within mesoporous nanosilica (mSiO2) matrix to yield zinc oxide nanoparticles embedded in mesoporous nanosilica (ZnO@mSiO2). ZnO@mSiO2 inhibited the growth of four strains of fungi in a dose dependant manner. A series of biochemical assays revealed generation of oxidative stress from ZnO@mSiO2 for such biocidal response. We proposed transient superoxide and its subsequent conversion to H2O2 played a pivotal role behind such biocidal response as revealed from our systematic evaluation. This resulted morphological alteration of fungi through increase in number of facets, in correlation we found up-regulation in oxidative stress related genes. Bioavailability within the fungal sample was confirmed from microscopic, spectroscopic, biophysical techniques. Protein carbonylation of fungal species was the chemical outcome of such above mentioned stress and quantified by high performance liquid chromatography (HPLC) via subsequent hydrazone derivatization. Several in vitro and in vivo evaluations revealed the biocompatibility of ZnO@mSiO2. Altogether this report claims a new biocidal agent with a detailed mode of action focusing on the origin and quantification of oxidative stress through biophysical and biochemical techniques for the first time for real time applications. Copyright © 2014 Elsevier Inc. All rights reserved.

S-Nitrosation and regulation of inducible nitric oxide synthase.

PubMed

Mitchell, Douglas A; Erwin, Phillip A; Michel, Thomas; Marletta, Michael A

2005-03-29

The inducible isoform of nitric oxide synthase (iNOS) and three zinc tetrathiolate mutants (C104A, C109A, and C104A/C109A) were expressed in Escherichia coli and purified. The mutants were found by ICP-AES and the zinc-specific PAR colorimetric assay to be zinc free, whereas the wild-type iNOS zinc content was 0.38 +/- 0.01 mol of Zn/mol of iNOS dimer. The cysteine mutants (C104A and C109A) had an activity within error of wild-type iNOS (2.24 +/- 0.12 micromol of NO min(-1) mg(-1)), but the double cysteine mutant had a modestly decreased activity (1.75 +/- 0.14 micromol of NO min(-1) mg(-1)). To determine if NO could stimulate release of zinc and dimer dissociation, wild-type protein was allowed to react with an NO donor, DEA/NO, followed by buffer exchange. ICP-AES of samples treated with 10 microM DEA/NO showed a decrease in zinc content (0.23 +/- 0.01 to 0.09 +/- 0.01 mol of Zn/mol of iNOS dimer) with no loss of heme iron. Gel filtration of wild-type iNOS treated similarly resulted in approximately 20% more monomeric iNOS compared to a DEA-treated sample. Only wild-type iNOS had decreased activity (42 +/- 2%) after reaction with 50 microM DEA/NO compared to a control sample. Using the biotin switch method under the same conditions, only wild-type iNOS had increased levels of S-biotinylation. S-Biotinylation was mapped to C104 and C109 on wild-type iNOS using LysC digestion and MALDI-TOF/TOF MS. Immunoprecipitation of iNOS from the mouse macrophage cell line, RAW-264.7, and the biotin switch method were used to confirm endogenous S-nitrosation of iNOS. The data show that S-nitrosation of the zinc tetrathiolate cysteine results in zinc release from the dimer interface and formation of inactive monomers, suggesting that this mode of inhibition might occur in vivo.

Properties of Zinc Oxide Nanoparticles and Their Activity Against Microbes

NASA Astrophysics Data System (ADS)

Siddiqi, Khwaja Salahuddin; ur Rahman, Aziz; Tajuddin; Husen, Azamal

2018-05-01

Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the UVA and UVB region of spectra due to wide bandgap. Impact of zinc oxide on biological functions depends on its morphology, particle size, exposure time, concentration, pH, and biocompatibility. They are more effective against microorganisms such as Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Sarcina lutea, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Pseudomonas vulgaris, Candida albicans, and Aspergillus niger. Mechanism of action has been ascribed to the activation of zinc oxide nanoparticles by light, which penetrate the bacterial cell wall via diffusion. It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.

Properties of Zinc Oxide Nanoparticles and Their Activity Against Microbes.

PubMed

Siddiqi, Khwaja Salahuddin; Ur Rahman, Aziz; Tajuddin; Husen, Azamal

2018-05-08

Zinc oxide is an essential ingredient of many enzymes, sun screens, and ointments for pain and itch relief. Its microcrystals are very efficient light absorbers in the UVA and UVB region of spectra due to wide bandgap. Impact of zinc oxide on biological functions depends on its morphology, particle size, exposure time, concentration, pH, and biocompatibility. They are more effective against microorganisms such as Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Sarcina lutea, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Pseudomonas vulgaris, Candida albicans, and Aspergillus niger. Mechanism of action has been ascribed to the activation of zinc oxide nanoparticles by light, which penetrate the bacterial cell wall via diffusion. It has been confirmed from SEM and TEM images of the bacterial cells that zinc oxide nanoparticles disintegrate the cell membrane and accumulate in the cytoplasm where they interact with biomolecules causing cell apoptosis leading to cell death.

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…

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.

Investigation of ZnO Nanowire Interfaces for Multi-Scale Composites

DTIC Science & Technology

2012-03-06

growth of zinc oxide ( ZnO ) nanowires on the surface of the...through the growth of zinc oxide ( ZnO ) nanowires on the surface of the reinforcing fibers. The nanowires functionally grade the interface, improve bonding...bulk composite. This has been accomplished through the growth of zinc oxide ( ZnO ) nanowires on the surface of the reinforcing fibers. ZnO

Anticancer activity of fungal L-asparaginase conjugated with zinc oxide nanoparticles.

PubMed

Baskar, G; Chandhuru, J; Sheraz Fahad, K; Praveen, A S; Chamundeeswari, M; Muthukumar, T

2015-01-01

Demand for developing novel delivery system for cancer treatment has increased due to the side effects present in intravenous injection of L-asparaginase. Nanoparticles are used for delivering the drugs to its destination in cancer cure. Nanobiocomposite of zinc oxide nanoparticles conjugated with L-asparaginase was produced by Aspergillus terreus and was confirmed using maximum UV-Vis absorption at 340 nm in the present work. The presence of functional groups like OH, C-H, -C=N and C=O on the surface of nanobiocomposite was found from Fourier transform infrared spectrum analysis. Size of the produced nanocomposite was found in the range of 28-63 nm using scanning electron microscope. The crystalline nature of the synthesized nanobiocomposites was confirmed by X-ray diffraction analysis. The presence of zinc oxide on synthesized nanobiocomposite was confirmed by energy dispersive spectrum analysis. The anti-cancerous nature of the synthesized zinc oxide conjugated L-asparaginase nanobiocomposite on MCF-7 cell line was studied using MTT assay. The viability of the MCF-7 cells was decreased to 35.02 % when it was treated with L-asparaginase conjugated zinc oxide nanobiocomposite. Hence it is proved that the synthesized nanobiocomposites of zinc oxide conjugated L-asparaginase has good anti-cancerous activity.

Crystal Structure Characterization of Thin Layer Zinc Oxide

NASA Astrophysics Data System (ADS)

Doyan, Aris; Susilawati; Azizatul Fitri, Siti; Ahzan, Sukainil

2017-05-01

In this research the characterization of the crystal structure of a thin layer of ZnO (zinc oxide) were synthesized by sol - gel method and spin coating deposited on a glass substrate. The samples were divided into three sol concentrations of 0.1, 0.3, 0.5 Molar and two deposition temperature is 350 °C, and 550 °C. UV-Vis. spectrophotometer results showed that in the spectrum of visible light (wavelength range 300-800 nm) has a transmittance value of which increases with increasing concentration and temperature deposition of zinc oxide, otherwise the value of the absorption and the band gap energy decreases with the addition of concentration and deposition temperature. The transmittances value of the highest and lowest absorption was 93.5% and 0.03 is at a concentration of 0.1 M and zinc oxide deposition temperature of 550 °C, with a value of band gap energy of 2.98 eV. The XRD results showed that the zinc oxide crystal orientation in the field of 013 with a crystal grain size 14.4472 nm. SEM results showed the surface morphology of zinc oxide such as rod-like.

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

2011-12-06

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. © 2011 American Chemical Society

Inhibition of poly(ADP-ribose)polymerase-1 and DNA repair by uranium

PubMed Central

Cooper, Karen L.; Dashner, Erica J.; Tsosie, Ranalda; Cho, Young Mi; Lewis, Johnnye

2015-01-01

Uranium has radiological and non-radiological effects within biological systems and there is increasing evidence for genotoxic and carcinogenic properties attributable to uranium through its heavy metal properties. In this study, we report that low concentrations of uranium (as uranyl acetate; <10 μM) is not cytotoxic to human embryonic kidney cells or normal human keratinocytes; however, uranium exacerbates DNA damage and cytotoxicity induced by hydrogen peroxide, suggesting that uranium may inhibit DNA repair processes. Concentrations of uranyl acetate in the low micromolar range inhibited the zinc finger DNA repair protein poly(ADP-ribose) polymerase (PARP)-1 and caused zinc loss from PARP-1 protein. Uranyl acetate exposure also led to zinc loss from the zinc finger DNA repair proteins Xeroderma Pigmentosum, Complementation Group A (XPA) and aprataxin (APTX). In keeping with the observed inhibition of zinc finger function of DNA repair proteins, exposure to uranyl acetate enhanced retention of induced DNA damage. Co-incubation of uranyl acetate with zinc largely overcame the impact of uranium on PARP-1 activity and DNA damage. These findings present evidence that low concentrations of uranium can inhibit DNA repair through disruption of zinc finger domains of specific target DNA repair proteins. This may provide a mechanistic basis to account for the published observations that uranium exposure is associated with DNA repair deficiency in exposed human populations. PMID:26627003

Inhibition of poly(ADP-ribose)polymerase-1 and DNA repair by uranium.

PubMed

Cooper, Karen L; Dashner, Erica J; Tsosie, Ranalda; Cho, Young Mi; Lewis, Johnnye; Hudson, Laurie G

2016-01-15

Uranium has radiological and non-radiological effects within biological systems and there is increasing evidence for genotoxic and carcinogenic properties attributable to uranium through its heavy metal properties. In this study, we report that low concentrations of uranium (as uranyl acetate; <10 μM) is not cytotoxic to human embryonic kidney cells or normal human keratinocytes; however, uranium exacerbates DNA damage and cytotoxicity induced by hydrogen peroxide, suggesting that uranium may inhibit DNA repair processes. Concentrations of uranyl acetate in the low micromolar range inhibited the zinc finger DNA repair protein poly(ADP-ribose) polymerase (PARP)-1 and caused zinc loss from PARP-1 protein. Uranyl acetate exposure also led to zinc loss from the zinc finger DNA repair proteins Xeroderma Pigmentosum, Complementation Group A (XPA) and aprataxin (APTX). In keeping with the observed inhibition of zinc finger function of DNA repair proteins, exposure to uranyl acetate enhanced retention of induced DNA damage. Co-incubation of uranyl acetate with zinc largely overcame the impact of uranium on PARP-1 activity and DNA damage. These findings present evidence that low concentrations of uranium can inhibit DNA repair through disruption of zinc finger domains of specific target DNA repair proteins. This may provide a mechanistic basis to account for the published observations that uranium exposure is associated with DNA repair deficiency in exposed human populations. Copyright © 2015 Elsevier Inc. All rights reserved.

Zinc deprivation mediates alcohol-induced hepatocyte IL-8 analog expression in rodents via an epigenetic mechanism.

PubMed

Zhao, Yantao; Zhong, Wei; Sun, Xiuhua; Song, Zhenyuan; Clemens, Dahn L; Kang, Y James; McClain, Craig J; Zhou, Zhanxiang

2011-08-01

Neutrophil infiltration caused by IL-8 production is a central mechanism in alcohol-induced hepatitis. This study was performed to examine if an epigenetic mechanism is involved in alcohol-induced IL-8 production. Mice were pair-fed an alcohol-containing liquid diet for 4 weeks. Alcohol exposure induced hepatitis as indicated by increased expression of keratinocyte-derived cytokine (mouse IL-8) and neutrophil infiltration. Alcohol exposure induced histone 3 hyperacetylation owing to inhibition of histone deacetylase (HDAC) in association with NF-κB activation. Cell culture studies showed that alcohol exposure induced IL-8 and cytokine-induced neutrophil chemoattractant-1 (CINC-1, rat IL-8) production in human VL-17A cells and rat H4IIEC3 cells, respectively, dependent on acetaldehyde production, oxidative stress, and zinc release. Zinc deprivation alone induced CINC-1 production and acted synergistically with lipopolysaccharide or tumor necrosis factor-α on CINC-1 production. Zinc deprivation induced histone 3 hyperacetylation at lysine 9 through suppression of HDAC activity. Zinc deprivation caused nuclear translocation of NF-κB, and reduced HDAC binding to NF-κB. Chromatin immunoprecipitation (ChIP) showed that zinc deprivation caused histone 3 hyperacetylation as well as increased NF-κB binding to the CINC-1 promoter. In conclusion, inactivation of HDAC caused by zinc deprivation is a novel mechanism underlying IL-8 up-regulation in alcoholic hepatitis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Experimental Investigation of Performance and emission characteristics of Various Nano Particles with Bio-Diesel blend on Di Diesel Engine

NASA Astrophysics Data System (ADS)

Karthik, N.; Goldwin Xavier, X.; Rajasekar, R.; Ganesh Bairavan, P.; Dhanseelan, S.

2017-05-01

Present study provides the effect of Zinc Oxide (ZnO) and Cerium Oxide (CeO2) nanoparticles additives on the Performance and emission uniqueness of Jatropha. Jatropha blended fuel is prepared by the emulsification technique with assist of mechanical agitator. Nano particles (Zinc Oxide (ZnO)) and Cerium Oxide (CeO2)) mixed with Jatropha blended fuel in mass fraction (100 ppm) with assist of an ultrasonicator. Experiments were conducted in single cylinder constant speed direct injection diesel engine for various test fuels. Performance results revealed that Brake Thermal Efficiency (BTE) of Jatropha blended Cerium Oxide (B20CE) is 3% and 11% higher than Jatropha blended zinc oxide (B20ZO) and Jatropha blended fuel (B20) and 4% lower than diesel fuel (D100) at full load conditions. Emission result shows that HC and CO emissions of Jatropha blended Cerium Oxide (B20CE) are (6%, 22%, 11% and 6%, 15%, 12%) less compared with Jatropha blended Zinc Oxide (B20ZO), diesel (D100) and Jatropha blended fuel (B20) at full load conditions. NOx emissions of Jatropha blended Cerium Oxide is 1 % higher than diesel fuel (D100) and 2% and 5% lower than Jatropha blended Zinc Oxide, and jatropha blended fuel.

Mild zinc deficiency in male and female rats: early postnatal alterations in renal nitric oxide system and morphology.

PubMed

Tomat, Analia Lorena; Veiras, Luciana Cecilia; Aguirre, Sofía; Fasoli, Héctor; Elesgaray, Rosana; Caniffi, Carolina; Costa, María Ángeles; Arranz, Cristina Teresa

2013-03-01

Fetal and postnatal zinc deficiencies induce an increase in arterial blood pressure and impair renal function in male adult rats. We therefore hypothesized that these renal alterations are present in early stages of life and that there are sexual differences in the adaptations to this nutritional injury. The aim was to study the effects of moderate zinc deficiency during fetal life and lactation on renal morphology, oxidative stress, apoptosis, and the nitric oxide system in male and female rats at 21 d of life. Female Wistar rats received low (8 ppm) or control (30 ppm) zinc diets from the beginning of pregnancy to weaning. Glomerulus number, morphology, oxidative stress, apoptotic cells, nitric oxide synthase activity, and protein expression were evaluated in the kidneys of offspring at 21 d. Zinc deficiency decreased the nephron number, induced glomerular hypertrophy, increased oxidative damage, and decreased nitric oxide synthase activity in the male and female rat kidneys. Nitric oxide synthase activity was not affected by inhibitors of the neuronal or inducible isoforms, so nitric oxide was mainly generated by the endothelial isoenzyme. Gender differences were observed in glomerular areas and antioxidant enzyme activities. Zinc deficiency during fetal life and lactation induces an early decrease in renal functional units, associated with a decrease in nitric oxide activity and an increase in oxidative stress, which would contribute to increased arterial blood pressure and renal dysfunction in adulthood. The sexual differences observed in this model may explain the dissimilar development of hypertension and renal diseases in adult life. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of Water on Ethanol Conversion over ZnO

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

Rahman, Muhammad Mahfuzur; Davidson, Stephen D.; Sun, Junming

2015-10-01

This work focuses on understanding the role of water on ethanol conversion over zinc oxide (ZnO). It was found that a competitive adsorption between ethanol and water occurs on ZnO, which leads to the blockage of the strong Lewis acid site by water on ZnO. As a result, both dehydration and dehydrogenation reactions are inhibited. However, the extent of inhibition for dehydration is orders of magnitude higher than that for dehydrogenation, leading to the shift of reaction pathway from ethanol dehydration to dehydrogenation. In the secondary reactions for acetaldehyde conversion, water inhibits the acetaldehyde aldol-condensation to crotonaldehyde, favoring the oxidationmore » of acetaldehyde to acetic acid, and then to acetone via ketonization at high temperature (i.e., 400 °C).« less

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.

Method of fabricating a catalytic structure

DOEpatents

Rollins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

2009-09-22

A precursor to a catalytic structure comprising zinc oxide and copper oxide. The zinc oxide has a sheet-like morphology or a spherical morphology and the copper oxide comprises particles of copper oxide. The copper oxide is reduced to copper, producing the catalytic structure. The catalytic structure is fabricated by a hydrothermal process. A reaction mixture comprising a zinc salt, a copper salt, a hydroxyl ion source, and a structure-directing agent is formed. The reaction mixture is heated under confined volume conditions to produce the precursor. The copper oxide in the precursor is reduced to copper. A method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure.

Sulfur dioxide leaching of spent zinc-carbon-battery scrap

NASA Astrophysics Data System (ADS)

Avraamides, J.; Senanayake, G.; Clegg, R.

Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2 M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25 °C. Alkaline leaching with 6 M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30 min at 30 °C using 0.1-1.0 M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1 M to 2 M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide.

Subtractive Plasma-Assisted-Etch Process for Developing High Performance Nanocrystalline Zinc-Oxide Thin-Film-Transistors

DTIC Science & Technology

2015-03-26

THIN - FILM - TRANSISTORS THESIS Thomas M. Donigan, First Lieutenant, USAF AFIT-ENG-MS-15-M-027 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR...DEVELOPING HIGH PERFORMANCE NANOCRYSTALLINE ZINC-OXIDE THIN - FILM - TRANSISTORS THESIS Presented to the Faculty Department of Electrical and...15-M-027 SUBTRACTIVE PLASMA-ASSISTED-ETCH PROCESS FOR DEVELOPING HIGH PERFORMANCE NANOCRYSTALLINE ZINC-OXIDE THIN - FILM - TRANSISTORS

Studies of Peptide-Mineral Interactions and Biosilicification

DTIC Science & Technology

2010-07-16

His). The effect of zinc oxide -binding peptides ( ZnO -BPs) on the morphology and formation of ZnO were studied using G-12 (GLHVMHKVAPPR) and EM-12...interactions with silica and zinc oxide . Detailed quantitative experimental studies together with molecular modeling studies have shown that G12 (GLHVMHKVAPPR...studies of a primitive 15. SUBJECT TERMS Peptides, zinc oxide , silica, silver, peptide-mineral interactions, computational chemistry, molecular

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Properties of ZnO nanocrystals prepared by radiation method

NASA Astrophysics Data System (ADS)

Čuba, Václav; Gbur, Tomáš; Múčka, Viliam; Nikl, Martin; Kučerková, Romana; Pospíšil, Milan; Jakubec, Ivo

2010-01-01

Zinc oxide nanoparticles were prepared by irradiation of aqueous solutions containing zinc(II) ions, propan-2-ol, polyvinyl alcohol, and hydrogen peroxide. Zinc oxide was found in solid phase either directly after irradiation, or after additional heat treatment. Various physicochemical parameters, including scintillation properties of prepared materials, were studied. After decomposition of impurities and annealing of oxygen vacancies, the samples showed intensive emission in visible spectral range and well-shaped exciton luminescence at 390-400 nm. The best scintillating properties had zinc oxide prepared from aqueous solutions containing zinc formate as initial precursor and hydrogen peroxide. Size of the crystalline particles ranged from tens to hundreds nm, depending on type of irradiated solution and post-irradiation thermal treatment.

Chemical stability and electrical performance of dual-active-layered zinc-tin-oxide/indium-gallium-zinc-oxide thin-film transistors using a solution process.

PubMed

Kim, Chul Ho; Rim, You Seung; Kim, Hyun Jae

2013-07-10

We investigated the chemical stability and electrical properties of dual-active-layered zinc-tin-oxide (ZTO)/indium-gallium-zinc-oxide (IGZO) structures (DALZI) with the durability of the chemical damage. The IGZO film was easily corroded or removed by an etchant, but the DALZI film was effectively protected by the high chemical stability of ZTO. Furthermore, the electrical performance of the DALZI thin-film transistor (TFT) was improved by densification compared to the IGZO TFT owing to the passivation of the pin holes or pore sites and the increase in the carrier concentration due to the effect of Sn(4+) doping.

In situ observation of the formation of hollow zinc oxide shells

DOE PAGES

Tringe, J. W.; Levie, H. W.; El-Dasher, B. S.; ...

2011-06-14

Single crystal zinc particles, 1–2 μm1–2 μm in diameter, were observed in situ with transmission electron microscopy during sublimation. The rate of sublimation is strongly dependent on the presence of a surface oxide layer. Near 375°, minimally oxidized Zn surfaces sublime in tens of seconds, consistent with a model in which the particle behaves similarly to an isolated microscale effusion cell. By contrast, zinc particles fully enclosed by oxide sublime less than one-tenth as quickly. Here these results provide new insight into the synthesis mechanisms of hollow ZnO microspheres and related structures formed from metallic zinc at elevated temperatures.

Ketamine-induced behavioural and brain oxidative changes in mice: an assessment of possible beneficial effects of zinc as mono- or adjunct therapy.

PubMed

Onaolapo, Olakunle James; Ademakinwa, Olayemi Quyyom; Olalekan, Temitayo Opeyemi; Onaolapo, Adejoke Yetunde

2017-09-01

We studied the influence of zinc, haloperidol or olanzapine on neurobehaviour (open-field, radial arm maze and elevated plus maze) and brain antioxidant status in vehicle- or ketamine-treated mice, with the aim of ascertaining the potentials of zinc in counteracting ketamine's effects. Experiment 1 assessed the effects of zinc in healthy animals and the relative degrees of modulation of ketamine's effects by zinc, haloperidol or olanzapine, respectively. Experiment 2 assessed the modulation of ketamine's effects following co-administration of zinc with haloperidol or olanzapine. Male mice weighing 18-20 g each were used. Animals were pretreated with ketamine (except vehicle, zinc, haloperidol and olanzapine controls) for 10 days before commencement of 14-day treatment (day 11-24) with vehicle, zinc, haloperidol or olanzapine (alone or in combination). Ketamine injection also continued alongside zinc and/or standard drugs in the ketamine-treated groups. Zinc, haloperidol and olanzapine were administered by gavage. Treatments were given daily and behaviours assessed on days 11 and 24. On day 24, animals were sacrificed and whole brain homogenates used for estimation of glutathione, nitric oxide and malondialdehyde (MDA) levels. Ketamine increased open-field behaviours, nitric oxide and MDA levels, while it decreased working memory, social interaction and glutathione. Administration of zinc alone or in combination with haloperidol or olanzapine was associated with variable degrees of reversal of these effects. Zinc may have the potential of a possible therapeutic agent and/or adjunct in the reversal of schizophrenia-like changes in behaviour and brain oxidative status.

Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling.

PubMed

Al-Naamani, Laila; Dobretsov, Sergey; Dutta, Joydeep; Burgess, J Grant

2017-02-01

Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

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

Ivetić, T.B., E-mail: tamara.ivetic@df.uns.ac.rs; Finčur, N.L.; Đačanin, Lj. 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{submore » 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}.« less

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.

Comparative Study of Antidiabetic Activity and Oxidative Stress Induced by Zinc Oxide Nanoparticles and Zinc Sulfate in Diabetic Rats.

PubMed

Nazarizadeh, Ali; Asri-Rezaie, Siamak

2016-08-01

In the current study, antidiabetic activity and toxic effects of zinc oxide nanoparticles (ZnO) were investigated in diabetic rats compared to zinc sulfate (ZnSO4) with particular emphasis on oxidative stress parameters. One hundred and twenty male Wistar rats were divided into two healthy and diabetic groups, randomly. Each major group was further subdivided into five subgroups and then orally supplemented with various doses of ZnO (1, 3, and 10 mg/kg) and ZnSO4 (30 mg/kg) for 56 consecutive days. ZnO showed greater antidiabetic activity compared to ZnSO4 evidenced by improved glucose disposal, insulin levels, and zinc status. The altered activities of erythrocyte antioxidant enzymes as well as raised levels of lipid peroxidation and a marked reduction of total antioxidant capacity were observed in rats receiving ZnO. ZnO nanoparticles acted as a potent antidiabetic agent, however, severely elicited oxidative stress particularly at higher doses.

Topical application of zinc oxide nanoparticles reduces bacterial skin infection in mice and exhibits antibacterial activity by inducing oxidative stress response and cell membrane disintegration in macrophages.

PubMed

Pati, Rashmirekha; Mehta, Ranjit Kumar; Mohanty, Soumitra; Padhi, Avinash; Sengupta, Mitali; Vaseeharan, Baskarlingam; Goswami, Chandan; Sonawane, Avinash

2014-08-01

Here we studied immunological and antibacterial mechanisms of zinc oxide nanoparticles (ZnO-NPs) against human pathogens. ZnO-NPs showed more activity against Staphylococcus aureus and least against Mycobacterium bovis-BCG. However, BCG killing was significantly increased in synergy with antituberculous-drug rifampicin. Antibacterial mechanistic studies showed that ZnO-NPs disrupt bacterial cell membrane integrity, reduce cell surface hydrophobicity and down-regulate the transcription of oxidative stress-resistance genes in bacteria. ZnO-NP treatment also augmented the intracellular bacterial killing by inducing reactive oxygen species production and co-localization with Mycobacterium smegmatis-GFP in macrophages. Moreover, ZnO-NPs disrupted biofilm formation and inhibited hemolysis by hemolysin toxin producing S. aureus. Intradermal administration of ZnO-NPs significantly reduced the skin infection, bacterial load and inflammation in mice, and also improved infected skin architecture. We envision that this study offers novel insights into antimicrobial actions of ZnO-NPs and also demonstrates ZnO-NPs as a novel class of topical anti-infective agent for the treatment of skin infections. This in-depth study demonstrates properties of ZnO nanoparticles in infection prevention and treatment in several skin infection models, dissecting the potential mechanisms of action of these nanoparticles and paving the way to human applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Zinc oxide nanoparticles induce rat retinal ganglion cell damage through bcl-2, caspase-9 and caspase-12 pathways.

PubMed

Guo, Dadong; Bi, Hongsheng; Wu, Qiuxin; Wang, Daoguang; Cui, Yan

2013-06-01

Nanomaterials, including zinc oxide (ZnO) nanoparticles, are being developed for a variety of commercial products. Recent reports showed that cells exposed to ZnO nanoparticles produced severe cytotoxicity accompanied by oxidative stress and genotoxicity. To understand the possible mechanism underlying oxidative stress of ZnO nanoparticles, the present investigation focused on the direct bioactivity of ZnO nanoparticles using a rat retinal ganglion cell (RGC-5) culture. At concentrations relevant to those used in vitro exposure of RGC-5 cells to ZnO nanoparticles, it was found that ZnO nanoparticles could inhibit cell proliferation in time- and concentration-dependent manners. Meanwhile, cell cycle arrest of S and G2/M phases occurred in RGC-5 cells induced by ZnO nanoparticles. Moreover, our results also demonstrated that the overproduction of reactive oxygen species (ROS) and elevated level of caspase-12 as well as decreased levels of bcl-2 and caspase-9 occurred after treatment with different concentrations of ZnO nanoparticles when compared to those in untreated cells. In summary, our findings suggest that ZnO nanoparticles could lead to the over generations of ROS and caspase-12 as well as decreased levels of bcl-2 and caspase-9. These results indicate that bcl-2, caspase-9 and caspase-12 may play significant roles in ZnO nanoparticle-induced RGC-5 cell damage.

Green Synthesis of Formulated Zinc Oxide Nanoparticles for Chemical Protection of Skin Care and Related Applications

NASA Astrophysics Data System (ADS)

Koppolu, Ramya

Nanomaterials have diversified applications based on the unique properties. These nanoparticles and functionalized nanocomposites have been studied in the health care filed. Nanoparticles are mostly used in sunscreens which are a part of human life. These sunscreens consist of titanium dioxide and zinc oxide nanoparticles. Due to the higher band crevices, they help the skin to protect from ultraviolet rays, for instance, ultraviolet B and ultraviolet A. A series of nanostructured zinc oxide nanoparticles were prepared by cost-effective chemical and bioinspired methods and variables were optimized. Highly stable and spherical zinc oxide nanoparticles were formulated by aloe vera ( Aloe barbadensis) plant extract and avocado (Persea americana Mill) fruit extract. The state-of-the-art instrumentation was used to characterize the morphology, elemental composition, and particle size distribution. X-ray diffraction data indicated highly crystalline and ultrafine nanoparticles were obtained from the colloidal methods. The X-ray photoelectron spectroscopy results showed the chemical state of zinc, carbon, and oxygen atoms were well-indexed and are used as fingerprint identification of the elements. Transmission electron microscopy images show the shape of particles were cubic and fiber shape contingent upon the protecting operators and heat treatment conditions. The toxicity studies of zinc oxide nanoparticles were found to cause an increase in nitric oxide, which is protecting against further oxidative stress and appears to be nontoxic.

Copper Doping of Zinc Oxide by Nuclear Transmutation

DTIC Science & Technology

2014-03-27

Copper Doping of Zinc Oxide by Nuclear Transmutation THESIS Matthew C. Recker, Captain, USAF AFIT-ENP-14-M-30 DEPARTMENT OF THE AIR FORCE AIR...NUCLEAR TRANSMUTATION THESIS Presented to the Faculty Department of Engineering Physics Graduate School of Engineering and Management Air Force...COPPER DOPING OF ZINC OXIDE BY NUCLEAR TRANSMUTATION Matthew C. Recker, BS Captain, USAF Approved: //signed// 27 February 2014 John W. McClory, PhD

Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: structural and optical studies by DRS, FT-IR, XRD, FESEM investigations.

PubMed

Habibi, Mohammad Hossein; Mardani, Maryam

2015-02-25

Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm(-1) can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm(-1) are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide. Copyright © 2014 Elsevier B.V. All rights reserved.

Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

NASA Astrophysics Data System (ADS)

Kumar, Rajeev; Kushwaha, Angad S.; Srivastava, Monika; Mishra, H.; Srivastava, S. K.

2018-03-01

In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

Immobilization Effect of Morphological, Thermal and Optical Properties in Biotemplate on Zinc Oxide Nanocomposite from Chitosan

NASA Astrophysics Data System (ADS)

Karpuraranjith, M.; Thambidurai, S.

Biotemplate-based zinc oxide nanocomposite was effectively prepared via simple chemical precipitation route. The functional groups of amino (-NH2), hydroxyl (-OH) and O-Zn-O were confirmed and characterized by FTIR spectroscopy. The structural and morphological properties were confirmed by XRD, UV-Vis DRS, HR-SEM and TEM analyses. The elemental composition of carbon, nitrogen, zinc and oxygen was confirmed by energy-dispersive X-ray analysis (EDAX) and Brunauer-Emmett-Teller high surface area of materials was estimated to be 52.49m2/g, respectively. Thermogravimetric analysis (TGA) shows that biotemplate on zinc oxide nanocomposite has higher thermal stability than chitosan matrix. The results demonstrate that biotemplate on zinc oxide matrix causes immobilization effect among the two components. Therefore, chitosan-ZnO nanocomposite has a microcrystalline morphological structure and also good thermal stability, so it can be a promising material for sensors, medical, tissue engineering and wastewater treatment applications.

Novel green synthetic strategy to prepare ZnO nanocrystals using rambutan (Nephelium lappaceum L.) peel extract and its antibacterial applications.

PubMed

Yuvakkumar, R; Suresh, J; Nathanael, A Joseph; Sundrarajan, M; Hong, S I

2014-08-01

In the present investigation, we report a sustainable novel green synthetic strategy to synthesis zinc oxide nanocrystals. This is the first report on sustainable biosynthesis of zinc oxide nanocrystals employing Nephelium lappaceum L., peel extract as a natural ligation agent. Green synthesis of zinc oxide nanocrystals was carried out via zinc-ellagate complex formation using rambutan peel wastes. The successful formation of zinc oxide nanocrystals was confirmed employing standard characterisation studies. A possible mechanism for the formation of ZnO nanocrystals with rambutan peel extract was also proposed. The prepared ZnO nanocrystals were coated on the cotton fabric and their antibacterial activity were analyzed. ZnO nanocrystals coated cotton showed good antibacterial activity towards Escherichia coli (E. coli), gram negative bacteria and Staphylococcus aureus (S. aureus), gram positive bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Rechargeable zinc cell with alkaline electrolyte which inhibits shape change in zinc electrode

DOEpatents

Adler, Thomas C.; McLarnon, Frank R.; Cairns, Elton J.

1995-01-01

An improved rechargeable zinc cell is described comprising a zinc electrode and another electrode such as, for example, a nickel-containing electrode, and having an electrolyte containing one or more hydroxides having the formula M(OH), one or more fluorides having the formula MF, and one or more carbonates having the formula M.sub.2 CO.sub.3, where M is a metal selected from the group consisting of alkali metals. The electrolyte inhibits shape change in the zinc electrode, i.e., the zinc electrode exhibits low shape change, resulting in an improved capacity retention of the cell over an number of charge-discharge cycles, while still maintaining high discharge rate characteristics.

Inhibiting the oxidation of diamond during preparing the vitrified dental grinding tools by depositing a ZnO coating using direct urea precipitation method.

PubMed

Wang, Yanhui; Yuan, Yungang; Cheng, Xiaozhe; Li, Xiaohu; Zang, Jianbing; Lu, Jing; Yu, Yiqing; Xu, Xipeng

2015-08-01

Oxidation of diamond during the manufacturing of vitrified dental grinding tools would reduce the strength and sharpness of tools. Zinc oxide (ZnO) coating was deposited on diamond particles by urea precipitation method to protect diamond in borosilicate glass. The FESEM results showed that the ZnO coating was formed by plate-shaped particles. According to the TG results, the onset oxidation temperature of the ZnO-coated diamond was about 70 °C higher than the pristine diamond. The EDS results showed that ZnO diffused into the borosilicate glass during sintering. As the result, the bending strength of the composites containing ZnO-coated diamond was increased by 24% compared to that of the composites containing pristine diamond. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Scale-up synthesis of zinc borate from the reaction of zinc oxide and boric acid in aqueous medium

NASA Astrophysics Data System (ADS)

Kılınç, Mert; Çakal, Gaye Ö.; Yeşil, Sertan; Bayram, Göknur; Eroğlu, İnci; Özkar, Saim

2010-11-01

Synthesis of zinc borate was conducted in a laboratory and a pilot scale batch reactor to see the influence of process variables on the reaction parameters and the final product, 2ZnO·3B 2O 3·3.5H 2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H 3BO 3:ZnO on the zinc borate formation reaction were examined at a constant temperature of 85 °C in a laboratory (4 L) and a pilot scale (85 L) reactor. Products obtained from the reaction in both reactors were characterized by chemical analysis, X-ray diffraction, particle size distribution analysis, thermal gravimetric analysis and scanning electron microscopy. The kinetic data for the zinc borate production reaction was fit by using the logistic model. The results revealed that the specific reaction rate, a model parameter, decreases with increase in particle size of zinc oxide and the presence of baffles, but increases with increase in stirring speed and purity of zinc oxide; however, it is unaffected with the changes in the amount of seed and reactants ratio. The reaction completion time is unaffected by scaling-up.

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; 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

Molecular basis for subtype-specificity and high-affinity zinc inhibition in the GluN1-GluN2A NMDA receptor amino terminal domain

PubMed Central

Romero-Hernandez, Annabel; Simorowski, Noriko; Karakas, Erkan

2016-01-01

Summary Zinc is vastly present in the mammalian brain and controls functions of various cell surface receptors to regulate neurotransmission. A distinctive characteristic of N-methyl-D-aspartate (NMDA) receptors containing a GluN2A subunit is that their ion channel activity is allosterically inhibited by a nano-molar concentration of zinc that binds to an extracellular domain called an amino terminal domain (ATD). Despite physiological importance, the molecular mechanism underlying the high-affinity zinc inhibition has been incomplete due to lack of a GluN2A ATD structure. Here we show the first crystal structures of the heterodimeric GluN1-GluN2A ATD, which provide the complete map of the high-affinity zinc binding site and reveals distinctive features from the ATD of the GluN1-GluN2B subtype. Perturbation of hydrogen bond networks at the hinge of the GluN2A bi-lobe structure affects both zinc inhibition and open probability supporting the general model where the bi-lobe motion in ATD regulates the channel activity in NMDA receptors. PMID:27916457

Zinc-oxide-based nanostructured materials for heterostructure solar cells

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

Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A., E-mail: vamoshnikov@mail.ru

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.

Acetone sensor based on zinc oxide hexagonal tubes

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

Hastir, Anita, E-mail: anitahastir@gmail.com; Singh, Onkar, E-mail: anitahastir@gmail.com; Anand, Kanika, E-mail: anitahastir@gmail.com

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.

Bandgap-Engineered Zinc-Tin-Oxide Thin Films for Ultraviolet Sensors.

PubMed

Cheng, Tien-Hung; Chang, Sheng-Po; Chang, Shoou-Jinn

2018-07-01

Zinc-tin-oxide thin-film transistors were prepared by radio frequency magnetron co-sputtering, while an identical zinc-tin-oxide thin film was deposited simultaneously on a clear glass substrate to facilitate measurements of the optical properties. When we adjusted the deposition power of ZnO and SnO2, the bandgap of the amorphous thin film was dominated by the deposition power of SnO2. Since the thin-film transistor has obvious absorption in the ultraviolet region owing to the wide bandgap, the drain current increases with the generation of electron-hole pairs. As part of these investigations, a zinc-tin-oxide thin-film transistor has been fabricated that appears to be very promising for ultraviolet applications.

Zirconium-based conversion film formation on zinc, aluminium and magnesium oxides and their interactions with functionalized molecules

NASA Astrophysics Data System (ADS)

Fockaert, L. I.; Taheri, P.; Abrahami, S. T.; Boelen, B.; Terryn, H.; Mol, J. M. C.

2017-11-01

Zirconium-based conversion treatment of zinc, aluminium and magnesium oxides have been studied in-situ using ATR-FTIR in a Kretschmann geometry. This set-up was coupled to an electrochemical cell, which allowed to obtain chemical and electrochemical information simultaneously as a function of conversion time. This elucidated the strong relation between physico-chemical surface properties and zirconium-based conversion kinetics. Whereas the surface hydroxyl density of zinc and aluminium increased during conversion, magnesium (hydr)oxide was shown to dissolve in the acid solution. Due to this dissolution, strong surface alkalization can be expected, explaining the rapid conversion kinetics. AES depth profiling was used to determine the final oxide thickness and elemental composition. This confirmed that magnesium is most active and forms a zirconium oxide layer approximately 10 times thicker than zinc. On the other hand, the presence of zirconium oxide on aluminium is very low and can be considered as not fully covering the metal oxide. Additionally, the converted oxide chemistry was related to the bonding mechanisms of amide functionalized molecules using ATR-FTIR and XPS. It was shown that inclusion of zirconium altered the acid-base properties, increasing the substrate proton donating capabilities in case of magnesium oxide and increasing hydrogen bonding and Bronsted interactions due to increased surface hydroxide fractions on zinc and aluminium substrates.

Low Plasma Zinc Is Associated with Higher Mitochondrial Oxidative Stress and Faster Liver Fibrosis Development in the Miami Adult Studies in HIV Cohort.

PubMed

Martinez, Sabrina S; Campa, Adriana; Li, Yinghui; Fleetwood, Christina; Stewart, Tiffanie; Ramamoorthy, Venkataraghavan; Baum, Marianna K

2017-04-01

Background: Oxidative stress and reduced antioxidants may be a trigger for liver fibrogenesis. Reducing oxidative stress through higher antioxidant concentration may be a potential antifibrotic target. Objective: We aimed to investigate longitudinally whether plasma zinc, an antioxidant, is related to mitochondrial oxidative stress and the progression of liver fibrosis in the Miami Adult Studies in HIV (MASH) cohort. Methods: A prospective observational cohort study was conducted in 487 predominantly African American HIV-monoinfected and HIV/hepatitis C virus (HCV)-coinfected adults with a mean ± SD age of 47.08 ± 7.67 y from the MASH cohort and followed for a median of 34 mo. Blood was collected for plasma zinc and measures were used to calculate the fibrosis-4 (FIB-4) score (aspartate amino transferase, alanine aminotransferase, and platelets). Plasma zinc deficiency was defined as <0.75 mg/L. Total DNA was extracted from peripheral blood mononuclear cells and mitochondrial DNA (mtDNA) 8-hydroxyguanosine (8-oxo-dG) was determined. Adjusted mixed models were used to assess the relations between zinc, stage of liver disease, and oxidative stress over time and compared between HIV and HIV/HCV groups. Results: Zinc concentrations (β: -0.368, SE = 0.172; P = 0.033) and deficiency were associated with lower FIB-4 scores over time (β: 0.381, SE = 0.118; P = 0.001). Compared with those who were not zinc deficient, zinc-deficient participants had an increased risk of having more-progressed liver disease (OR: 1.91; 95% CI: 1.15, 3.16; P = 0.012). Higher mtDNA 8-oxo-dG was associated with zinc deficiency (β: 0.049, SE = 0.024; P = 0.044) and higher FIB-4 scores over time (β: 0.597, SE = 0.168, P < 0.001). Conclusions: Lower plasma zinc concentrations were associated with liver fibrosis progression and mitochondrial oxidative stress in the HIV and HIV/HCV groups. Zinc may play a role in the impact of liver disease outcomes. © 2017 American Society for Nutrition.

Low Plasma Zinc Is Associated with Higher Mitochondrial Oxidative Stress and Faster Liver Fibrosis Development in the Miami Adult Studies in HIV Cohort1234

PubMed Central

Martinez, Sabrina S; Campa, Adriana; Li, Yinghui; Fleetwood, Christina; Stewart, Tiffanie; Ramamoorthy, Venkataraghavan; Baum, Marianna K

2017-01-01

Background: Oxidative stress and reduced antioxidants may be a trigger for liver fibrogenesis. Reducing oxidative stress through higher antioxidant concentration may be a potential antifibrotic target. Objective: We aimed to investigate longitudinally whether plasma zinc, an antioxidant, is related to mitochondrial oxidative stress and the progression of liver fibrosis in the Miami Adult Studies in HIV (MASH) cohort. Methods: A prospective observational cohort study was conducted in 487 predominantly African American HIV-monoinfected and HIV/hepatitis C virus (HCV)–coinfected adults with a mean ± SD age of 47.08 ± 7.67 y from the MASH cohort and followed for a median of 34 mo. Blood was collected for plasma zinc and measures were used to calculate the fibrosis-4 (FIB-4) score (aspartate amino transferase, alanine aminotransferase, and platelets). Plasma zinc deficiency was defined as <0.75 mg/L. Total DNA was extracted from peripheral blood mononuclear cells and mitochondrial DNA (mtDNA) 8-hydroxyguanosine (8-oxo-dG) was determined. Adjusted mixed models were used to assess the relations between zinc, stage of liver disease, and oxidative stress over time and compared between HIV and HIV/HCV groups. Results: Zinc concentrations (β: −0.368, SE = 0.172; P = 0.033) and deficiency were associated with lower FIB-4 scores over time (β: 0.381, SE = 0.118; P = 0.001). Compared with those who were not zinc deficient, zinc-deficient participants had an increased risk of having more-progressed liver disease (OR: 1.91; 95% CI: 1.15, 3.16; P = 0.012). Higher mtDNA 8-oxo-dG was associated with zinc deficiency (β: 0.049, SE = 0.024; P = 0.044) and higher FIB-4 scores over time (β: 0.597, SE = 0.168, P < 0.001). Conclusions: Lower plasma zinc concentrations were associated with liver fibrosis progression and mitochondrial oxidative stress in the HIV and HIV/HCV groups. Zinc may play a role in the impact of liver disease outcomes. PMID:28228506

Reduction in the Band Gap of Manganese-Doped Zinc Oxide: Role of the Oxidation State

NASA Astrophysics Data System (ADS)

Sharma, Sonia; Ramesh, Pranith; Swaminathan, P.

2015-12-01

Manganese-doped zinc oxide powders were synthesized by solid state reaction of the respective oxides. The high-temperature conditions were chosen such that multiple valence states of manganese were doped in the host zinc oxide lattice. Structural characterization was carried out to confirm the doping and to find the maximum amount of manganese that can be incorporated. Diffuse reflectance spectroscopy was used to measure the optical band gap of the doped sample and the lowering with respect to pure ZnO was attributed to the presence of higher oxidation states of manganese. The presence of these oxidation states was confirmed using x-ray photoelectron spectroscopy. The study shows that a solid state reaction is a viable route for synthesizing doped metal oxides with desired optical properties.

Prevention of "nitrosative stress" by a nutritional supplement (LaVita®) - a randomized placebo controlled double blind clinical trial with healthy volunteers.

PubMed

Muss, Claus; Mosgoeller, Wilhelm; Endler, Thomas

2016-10-01

A common pathomechanism involved in many degenerative manifestations of non-communicable diseases is nitrosative stress, giving rise to a chronic insidious inflammation causing silent inflammation at a cellular level. The release of nitric oxide inhibits multiple enzyme reactions with reduced oxidative phosphorylation and mitochondrial ATP depletion. We hypothesized that enzyme-inhibition can be alleviated by micronutrient supply, and studied laboratory parameters associated with nitrosative stress (nitrotyrosine, mitochondrial activity) after a micronutrient supplementation (a multivitamin mineral and trace element formulation as verum: LaVita®) and a placebo in healthy volunteers (n=150) for six months. Mean nitrotyrosine levels dropped significantly after 3 month in the verum and placebo group, whereas mitochondrial activity increased after three month in the verum group (p=0,087), but not in the placebo group (p=0,990). Ubiquinone - an essential ingredient for mitochondrial function- increased after six months in the verum group, but not after placebo consumption (p=0,001). Serum zinc and cellular zinc increased steadily after 3 and 6 month verum intake (p<0,001). As the enzyme superoxide dismutase (SOD) is mainly involved in the formation of nitrosative stress (peroxides) we measured the activity, and found significant differences in the placebo and verum group after 3 and 6 month (p=0,050 and p=0,003 respectively). We conclude that a balanced combination of vital nutrients may reduce nitrosative stress and silent inflammation, and consequently the risk for various forms of degenerative diseases.

The Molecular Basis of Inactivation of Metronidazole-Resistant Helicobacter pylori Using Polyethyleneimine Functionalized Zinc Oxide Nanoparticles

PubMed Central

Chowdhury, Rukhsana; Chakrabarti, Pinak

2013-01-01

In view of the world wide prevalence of Helicobacter pylori infection, its potentially serious consequences, and the increasing emergence of antibiotic resistant H. pylori strains there is an urgent need for the development of alternative strategies to combat the infection. In this study it has been demonstrated that polyethyleneimine (PEI) functionalized zinc oxide (ZnO) nanoparticles (NPs) inhibit the growth of a metronidazole-resistant strain of H. pylori and the molecular basis of the anti-bacterial activity of ZnO-PEI NP has been investigated. The ZnO-PEI NP was synthesized using a wet chemical method with a core size of approximately 3–7 nm. Internalization and distribution of ZnO-PEI NP without agglomeration was observed in H. pylori cytosol by electron microscopy. Several lines of evidence including scanning electron microscopy, propidium iodide uptake and ATP assay indicate severe membrane damage in ZnO-PEI NP treated H. pylori. Intracellular ROS generation increased rapidly following the treatment of H. pylori with ZnO-PEI NP and extensive degradation of 16S and 23S rRNA was observed by quantitative reverse-transcriptase PCR. Finally, considerable synergy between ZnO-PEI NP and antibiotics was observed and it has been demonstrated that the concentration of ZnO-PEI NP (20 µg/ml) that is non-toxic to human cells could be used in combination with sub-inhibitory concentrations of antibiotics for the inhibition of H. pylori growth. PMID:23951006

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...

Fruit peel extract mediated green synthesis of zinc oxide nanoparticles

NASA Astrophysics Data System (ADS)

Nava, O. J.; Soto-Robles, C. A.; Gómez-Gutiérrez, C. M.; Vilchis-Nestor, A. R.; Castro-Beltrán, A.; Olivas, A.; Luque, P. A.

2017-11-01

This work presents a study of the effects on the photocatalytic capabilities of zinc oxide nanoparticles when prepared via green synthesis using different fruit peel extracts as reducing agents. Zinc nitrate was used as a source of the zinc ions, while Lycopersicon esculentum (tomato), Citrus sinensis (orange), Citrus paradisi (grapefruit) and Citrus aurantifolia (lemon) contributed their peels for extracts. The Synthesized Samples were studied and characterized through Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and High Resolution Transmission Electron Microscopy (HRTEM). All samples presented a band at 618 cm-1, indicating the presence of the Znsbnd O bond. The different samples all presented the same hexagonal crystal growth in their structure, the Wurtzite phase. The surface morphology of the nanoparticles showed that, depending on the extract used, the samples vary in size and shape distribution due to the chemical composition of the extracts. The photocatalytic properties of the zinc oxide samples were tested through UV light aided degradation of methylene blue. Most samples exhibited degradation rates at 180 min of around 97%, a major improvement when compared to chemically synthesized commercially available zinc oxide nanoparticles.

Characterizing and simulation the scintillation properties of zinc oxide nanowires in AAO membrane for medical imaging applications

NASA Astrophysics Data System (ADS)

Esfandi, F.; Saramad, S.; Rezaei Shahmirzadi, M.

2017-07-01

In this work, a new method is proposed for extracting some X-ray detection properties of ZnO nanowires electrodeposited on Anodized Aluminum Oxide (AAO) nanoporous template. The results show that the detection efficiency for 12μm thickness of zinc oxide nano scintillator at an energy of 9.8 keV, near the K-edge of ZnO (9.65 keV), is 24%. The X-rays that interact with AAO can also generate electrons that reach the nano scintillator. The scintillation events of these electrons are seen as a low energy tail in the spectrum. In addition, it is found that all the X-rays that are absorbed in 300 nm thickness of the gold layer on the top of the zinc oxide nanowires can participate in the scintillation process with an efficiency of 6%. Hence, the scintillation detection efficiency of the whole detector for 9.8 keV X-ray energy is 30%. The simulation results from Geant4 and the experimental detected photons per MeV energy deposition are also used to extract the light yield of the zinc oxide nano scintillator. The results show that the light yield of the zinc oxide nanowires deposited by the electrochemical method is approximately the same as for single crystal zinc oxide scintillator (9000). Much better spatial resolution of this nano scintillator in comparison to the bulk ones is an advantage which candidates this nano scintillator for medical imaging applications.

Synthesis, structural characterization and DNA interaction of zinc complex from 2,6-diacetylpyridine dihydrazone and {4-[(2E)-2-(hydroxyimino)acetyl]phenoxy} acetic acid.

PubMed

Gup, Ramazan; Gökçe, Cansu; Dilek, Nefise

2015-03-01

A new water soluble zinc complex has been prepared and structurally characterized. The Zn(II) complex was synthesized by the reaction of 2,6-diacetylpyridine dihydrazone (dph) with {4-[(2E)-2-(hydroxyimino)acetyl]phenoxy} acetic acid (H₂L) in the presence of zinc(II) acetate. Single crystal X-ray diffraction study revealed that the zinc ion is situated in distorted trigonal-bipyramidal environment where the equatorial position is occupied by the nitrogen atom of pyridine ring and the oxygen atoms of acetate groups of two oxime ligands (H₂L) whereas the axial positions of the zinc complex are occupied by the imine nitrogen atoms of dph ligand. Characterization of the complex with FTIR, (1)H and (13)C NMR, UV-vis and elemental analysis also confirmed the proposed structure. Interaction of the Zn(II) complex with calf-thymus DNA (CT-DNA) was investigated through UV-vis spectroscopy and viscosity measurements. The results suggest that the complex preferably bind to DNA through the groove binding mode. The zinc complex cleaves plasmid pBR 322 DNA in the presence and absence of an oxidative agent (H₂O₂), possibly through a hydrolytic pathway which is also supported by DNA cleave experiments in the presence of different radical scavengers. The nuclease activity of the zinc complex significantly depends on concentration of the complex and incubation time both in the presence and absence of H₂O₂. DNA cleave activity is inhibited in the presence of methyl green indicating that the zinc complex seems to bind the major groove of DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of Chronic and Acute Zinc Supplementation on Myocardial Ischemia-Reperfusion Injury in Rats.

PubMed

Ozyıldırım, Serhan; Baltaci, Abdulkerim Kasim; Sahna, Engin; Mogulkoc, Rasim

2017-07-01

The present study aims to explore the effects of chronic and acute zinc sulfate supplementation on myocardial ischemia-reperfusion injury in rats. The study registered 50 adult male rats which were divided into five groups in equal numbers as follows: group 1, normal control; group 2, sham; group 3, myocardial ischemia reperfusion (My/IR): the group which was fed on a normal diet and in which myocardial I/R was induced; group 4, myocardial ischemia reperfusion + chronic zinc: (5 mg/kg i.p. zinc sulfate for 15 days); and group 5, myocardial ischemia reperfusion + acute zinc: the group which was administered 15 mg/kg i.p. zinc sulfate an hour before the operation and in which myocardial I/R was induced. The collected blood and cardiac tissue samples were analyzed using spectrophotometric method to determine levels of MDA, as an indicator of tissue injury, and GSH, as an indicator of antioxidant activity. The highest plasma and heart tissue MDA levels were measured in group 3 (p < 0.05). Group 5 had lower MDA values than group 3, while group 4 had significantly lower MDA values than groups 3 and 5 (p < 0.05). The highest erythrocyte GSH values were found in group 4 (p < 0.05). Erythrocyte GSH values in group 5 were higher than those in group 3 (p < 0.05). The highest GSH values in heart tissue were measured in group 4 (p < 0.05). The results of the study reveal that the antioxidant activity inhibited by elevated oxidative stress in heart ischemia reperfusion in rats is restored partially by acute zinc administration and markedly by chronic zinc supplementation.

Oxidative stress upregulates zinc uptake activity via Zrt/Irt-like protein 1 (ZIP1) in cultured mouse astrocytes.

PubMed

Furuta, Takahiro; Ohshima, Chiaki; Matsumura, Mayu; Takebayashi, Naoto; Hirota, Emi; Mawaribuchi, Toshiki; Nishida, Kentaro; Nagasawa, Kazuki

2016-04-15

Zinc released from glutamatergic boutons and astrocytes acts as neuro- and glio-transmitters, and thus its extracellular level has to be strictly regulated. We previously revealed that uptake of zinc by astrocytes plays a critical role in its clearance, and zinc transporter Zrt/Irt-like protein 1 (ZIP1) is the molecule responsible for the uptake. However, it is unknown whether or not the functionality of the zinc clearance system is altered under oxidative stress-loaded conditions. Here, we characterized zinc uptake by oxidative stress-loaded astrocytes. Cultured mouse astrocytes were treated with hydrogen peroxide (H2O2) to load oxidative stress. Functional expression of ZIP1 in astrocytes was evaluated by means of (65)Zn uptake, Western blotting and immunocytochemical analysis. Treatment of astrocytes with 0.4mM H2O2 for 24h increased the expression levels of glial fibrillary acidic protein and 4-hydroxynonenal without significant decreases in their viability, indicating that induction of oxidative stress in astrocytes. Under oxidative stress-loaded conditions, astrocytes exhibited increased (65)Zn uptake activity, and the maximum uptake velocity for the uptake was significantly increased compared to that in the control group, while there was no change in the Michaelis constants, which were almost identical to that of mouse ZIP1. In the H2O2-treated astrocytes, the expression levels of ZIP1 were significantly increased in the cellular and plasma membrane fractions. It appears that under oxidative stress-loaded conditions, astrocytes exhibit increased zinc clearance activity and this is due, at least in part, to increased ZIP1 expression. Copyright © 2016 Elsevier Inc. All rights reserved.

Oxidative stress-induced increase of intracellular zinc in astrocytes decreases their functional expression of P2X7 receptors and engulfing activity.

PubMed

Furuta, Takahiro; Mukai, Ayumi; Ohishi, Akihiro; Nishida, Kentaro; Nagasawa, Kazuki

2017-12-01

Neuron-glia communication mediated by neuro- and glio-transmitters such as ATP and zinc is crucial for the maintenance of brain homeostasis, and its dysregulation is found under pathological conditions. It is reported that under oxidative stress-loaded conditions, astrocytes exhibit increased intra- and extra-cellular labile zinc, the latter triggering microglial M1 activation, while the pathophysiological role of the former remains unrevealed. In this study, we examined whether the oxidative stress-induced increase of intracellular labile zinc is involved in the P2X7 receptor (P2X7R)-mediated regulation of astrocytic engulfing activity. The exposure of cultured astrocytes to sub-lethal oxidative stress through their treatment with 400 μM H 2 O 2 increased intracellular labile zinc, of which the concentration reached a peak level of approximately 2 μM at 2 h after the treatment. In astrocytes under sub-lethal oxidative stress, the uptake of YO-PRO-1 and latex beads as markers for P2X7R channel/pore activity and astrocytic engulfing activity, respectively, was decreased, and these decreased activities were accompanied by decreased expression of P2X7R at the plasma membrane via intracellular labile zinc-mediated translocation of it. With the oxidative stress, the expression level of full length P2X7R relative to that of its splice variants in astrocytes was decreased, leading to a decrease of the relative expression of the trimer consisting of full length P2X7R. Collectively, sub-lethal oxidative stress induces an astrocytic modal shift from the normal resting engulfing mode to the activated astrogliosis mode via an intracellular labile zinc-mediated decrease of the functional expression of P2X7R.

Zinc stimulates glucose oxidation and glycemic control by modulating the insulin signaling pathway in human and mouse skeletal muscle cell lines.

PubMed

Norouzi, Shaghayegh; Adulcikas, John; Sohal, Sukhwinder Singh; Myers, Stephen

2018-01-01

Zinc is a metal ion that is an essential cell signaling molecule. Highlighting this, zinc is an insulin mimetic, activating cellular pathways that regulate cellular homeostasis and physiological responses. Previous studies have linked dysfunctional zinc signaling with several disease states including cancer, obesity, cardiovascular disease and type 2 diabetes. The present study evaluated the insulin-like effects of zinc on cell signaling molecules including tyrosine, PRSA40, Akt, ERK1/2, SHP-2, GSK-3β and p38, and glucose oxidation in human and mouse skeletal muscle cells. Insulin and zinc independently led to the phosphorylation of these proteins over a 60-minute time course in both mouse and human skeletal muscle cells. Similarly, utilizing a protein array we identified that zinc could active the phosphorylation of p38, ERK1/2 and GSK-3B in human and ERK1/2 and GSK-3B in mouse skeletal muscle cells. Glucose oxidation assays were performed on skeletal muscle cells treated with insulin, zinc, or a combination of both and resulted in a significant induction of glucose consumption in mouse (p<0.01) and human (p<0.05) skeletal muscle cells when treated with zinc alone. Insulin, as expected, increased glucose oxidation in mouse (p<0.001) and human (0.001) skeletal muscle cells, however the combination of zinc and insulin did not augment glucose consumption in these cells. Zinc acts as an insulin mimetic, activating key molecules implicated in cell signaling to maintain glucose homeostasis in mouse and human skeletal muscle cells. Zinc is an important metal ion implicated in several biological processes. The role of zinc as an insulin memetic in activating key signaling molecules involved in glucose homeostasis could provide opportunities to utilize this ion therapeutically in treating disorders associated with dysfunctional zinc signaling.

Room temperature ferromagnetism in liquid-phase pulsed laser ablation synthesized nanoparticles of nonmagnetic oxides

NASA Astrophysics Data System (ADS)

Singh, S. C.; Kotnala, R. K.; Gopal, R.

2015-08-01

Intrinsic Room Temperature Ferromagnetism (RTF) has been observed in undoped/uncapped zinc oxide and titanium dioxide spherical nanoparticles (NPs) obtained by a purely green approach of liquid phase pulsed laser ablation of corresponding metal targets in pure water. Saturation magnetization values observed for zinc oxide (average size, 9 ± 1.2 nm) and titanium dioxide (average size, 4.4 ± 0.3 nm) NPs are 62.37 and 42.17 memu/g, respectively, which are several orders of magnitude larger than those of previous reports. In contrast to the previous works, no postprocessing treatments or surface modification is required to induce ferromagnetism in the case of present communication. The most important result, related to the field of intrinsic ferromagnetism in nonmagnetic materials, is the observation of size dependent ferromagnetism. Degree of ferromagnetism in titanium dioxide increases with the increase in particle size, while it is reverse for zinc oxide. Surface and volume defects play significant roles for the origin of RTF in zinc oxide and titanium dioxide NPs, respectively. Single ionized oxygen and neutral zinc vacancies in zinc oxide and oxygen and neutral/ionized titanium vacancies in titanium dioxide are considered as predominant defect centres responsible for observed ferromagnetism. It is expected that origin of ferromagnetism is a consequence of exchange interactions between localized electron spin moments resulting from point defects.

Room temperature ferromagnetism in liquid-phase pulsed laser ablation synthesized nanoparticles of nonmagnetic oxides

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

Singh, S. C., E-mail: subhash.laserlab@gmail.com; Gopal, R.; Kotnala, R. K.

2015-08-14

Intrinsic Room Temperature Ferromagnetism (RTF) has been observed in undoped/uncapped zinc oxide and titanium dioxide spherical nanoparticles (NPs) obtained by a purely green approach of liquid phase pulsed laser ablation of corresponding metal targets in pure water. Saturation magnetization values observed for zinc oxide (average size, 9 ± 1.2 nm) and titanium dioxide (average size, 4.4 ± 0.3 nm) NPs are 62.37 and 42.17 memu/g, respectively, which are several orders of magnitude larger than those of previous reports. In contrast to the previous works, no postprocessing treatments or surface modification is required to induce ferromagnetism in the case of present communication. The most important result, relatedmore » to the field of intrinsic ferromagnetism in nonmagnetic materials, is the observation of size dependent ferromagnetism. Degree of ferromagnetism in titanium dioxide increases with the increase in particle size, while it is reverse for zinc oxide. Surface and volume defects play significant roles for the origin of RTF in zinc oxide and titanium dioxide NPs, respectively. Single ionized oxygen and neutral zinc vacancies in zinc oxide and oxygen and neutral/ionized titanium vacancies in titanium dioxide are considered as predominant defect centres responsible for observed ferromagnetism. It is expected that origin of ferromagnetism is a consequence of exchange interactions between localized electron spin moments resulting from point defects.« less

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Co-precipitation synthesis of nano-composites consists of zinc and tin oxides coatings on glass with enhanced photocatalytic activity on degradation of Reactive Blue 160 KE2B.

PubMed

Habibi, Mohammad Hossein; Mardani, Maryam

2015-02-25

Nano-composite containing zinc oxide-tin oxide was obtained by a facile co-precipitation route using tin chloride tetrahydrate and zinc chloride as precursors and coated on glass by Doctor Blade deposition. The crystalline structure and morphology of composites were evaluated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The XRD results showed peaks relative to zinc oxide with hexagonal wurtzite structure and tin oxide with tetragonal structure. FESEM observations showed that the nano-composite consisted of aggregates of particles with an average particle size of 18 nm. The photocatalytic activity of the pure SnO2, pure ZnO, ZnSnO3-Zn2SnO4 and ZnO-SnO2 nano-structure thin films was examined using the degradation of a textile dye Reactive Blue 160 (KE2B). ZnO-SnO2 nano-composite showed enhanced photo-catalytic activity than the pure zinc oxide and tin oxide. The enhanced photo-catalytic activity of the nano-composite was ascribed to an improved charge separation of the photo-generated electron-hole pairs. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel hybrid materials based on the vanadium oxide nanobelts

NASA Astrophysics Data System (ADS)

Zabrodina, G. S.; Makarov, S. G.; Kremlev, K. V.; Yunin, P. A.; Gusev, S. A.; Kaverin, B. S.; Kaverina, L. B.; Ketkov, S. Yu.

2016-04-01

Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V2O5·nH2O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB - cetyltrimethylammonium bromide, TBAB - tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA)0.33V2O5 flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA)0.33V2O5, (TBA)0.16V2O5 nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

Computational exploration of zinc binding groups for HDAC inhibition.

PubMed

Chen, Kai; Xu, Liping; Wiest, Olaf

2013-05-17

Histone deacetylases (HDACs) have emerged as important drug targets in epigenetics. The most common HDAC inhibitors use hydroxamic acids as zinc binding groups despite unfavorable pharmacokinetic properties. A two-stage protocol of M05-2X calculations of a library of 48 fragments in a small model active site, followed by QM/MM hybrid calculations of the full enzyme with selected binders, is used to prospectively select potential bidentate zinc binders. The energetics and interaction patterns of several zinc binders not previously used for the inhibition of HDACs are discussed.

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

NASA Astrophysics Data System (ADS)

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

2011-08-01

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

Zinc Oxide—From Synthesis to Application: A Review

PubMed Central

Kołodziejczak-Radzimska, Agnieszka; Jesionowski, Teofil

2014-01-01

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

Photoluminescence of Porous Silicon-Zinc Oxide Hybrid structures

NASA Astrophysics Data System (ADS)

Olenych, I. B.; Monastyrskii, L. S.; Luchechko, A. P.

2017-03-01

Arrays of ZnO nanostructures, which are optically transparent in the visible range, were grown on the surface of porous silicon by electrochemical deposition. Photoluminescence excitation and emission spectra of the obtained hybrid structures were investigated in 220-450 and 400-800 nm regions, respectively. It is established that multicolor emission is formed by combining the luminescence bands of porous silicon and zinc oxide. The possibility of controlling the photoluminescence spectra by changing the excitation energy is demonstrated. It is revealed that thermal annealing has an effect on the luminescent properties of porous silicon/zinc oxide hybrid structures. Thermal processing at 500°C leads to a sharp decrease of long-wavelength luminescence associated with porous silicon and to an increase of short-wavelength luminescence intensity related to zinc oxide.

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

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

Papazoglou, M.; Chaliampalias, D.; Vourlias, G.

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 steelmore » 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.« less

Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals.

PubMed

Buonsanti, Raffaella; Llordes, Anna; Aloni, Shaul; Helms, Brett A; Milliron, Delia J

2011-11-09

Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films.

Zinc Salts Block Hepatitis E Virus Replication by Inhibiting the Activity of Viral RNA-Dependent RNA Polymerase.

PubMed

Kaushik, Nidhi; Subramani, Chandru; Anang, Saumya; Muthumohan, Rajagopalan; Shalimar; Nayak, Baibaswata; Ranjith-Kumar, C T; Surjit, Milan

2017-11-01

Hepatitis E virus (HEV) causes an acute, self-limiting hepatitis in healthy individuals and leads to chronic disease in immunocompromised individuals. HEV infection in pregnant women results in a more severe outcome, with the mortality rate going up to 30%. Though the virus usually causes sporadic infection, epidemics have been reported in developing and resource-starved countries. No specific antiviral exists against HEV. A combination of interferon and ribavirin therapy has been used to control the disease with some success. Zinc is an essential micronutrient that plays crucial roles in multiple cellular processes. Zinc salts are known to be effective in reducing infections caused by few viruses. Here, we investigated the effect of zinc salts on HEV replication. In a human hepatoma cell (Huh7) culture model, zinc salts inhibited the replication of genotype 1 (g-1) and g-3 HEV replicons and g-1 HEV infectious genomic RNA in a dose-dependent manner. Analysis of a replication-defective mutant of g-1 HEV genomic RNA under similar conditions ruled out the possibility of zinc salts acting on replication-independent processes. An ORF4-Huh7 cell line-based infection model of g-1 HEV further confirmed the above observations. Zinc salts did not show any effect on the entry of g-1 HEV into the host cell. Furthermore, our data reveal that zinc salts directly inhibit the activity of viral RNA-dependent RNA polymerase (RdRp), leading to inhibition of viral replication. Taken together, these studies unravel the ability of zinc salts in inhibiting HEV replication, suggesting their possible therapeutic value in controlling HEV infection. IMPORTANCE Hepatitis E virus (HEV) is a public health concern in resource-starved countries due to frequent outbreaks. It is also emerging as a health concern in developed countries owing to its ability to cause acute and chronic infection in organ transplant and immunocompromised individuals. Although antivirals such as ribavirin have been used to treat HEV cases, there are known side effects and limitations of such therapy. Our discovery of the ability of zinc salts to block HEV replication by virtue of their ability to inhibit the activity of viral RdRp is important because these findings pave the way to test the efficacy of zinc supplementation therapy in HEV-infected patients. Since zinc supplementation therapy is known to be safe in healthy individuals and since high-dose zinc is used in the treatment of Wilson's disease, it may be possible to control HEV-associated health problems following a similar treatment regimen. Copyright © 2017 American Society for Microbiology.

Comparative Evaluation of Antibacterial Effect of Dental Luting Cements on Streptococcus mutans and Lactobacillus acidophilus: An In vitro Study.

PubMed

Feroz, Sma; Bhoyar, A; Khan, S

2016-12-01

This study aimed at evaluating and comparing the antibacterial activity of six types of dental luting cements on Streptococcus mutans and Lactobacillus acidophilus using the agar diffusion test (ADT) and the direct-contact test (DCT). The antibacterial activity in ADT was measured based on the diameter of the zone of inhibition formed, whereas in DCT the density of the bacterial suspension was measured. The lower the density of the suspension, the more antibacterial activity the cement possesses. Agar diffusion test was carried out on the bacteria. After an incubation period of 24 hours, the plates were checked for the presence of zone of inhibition. In DCT the cement was mixed and applied. Once the cement was set, bacterial suspension and brain-heart infusion medium was poured and incubated for 24 hours. After 24 hours, the plate was placed in the enzyme-linked immunosorbent assay plate reader, which measured the optical density of the fluid. The first set of data was recorded approximately 1 hour after incubation. Overall, three sets of data were recorded. Additional experiments were performed on set test materials that were allowed to age for 24 hours, 1 week, 1, 3, and 6 months. When using ADT only two cements zinc oxide eugenol (ZOE) and zinc polycarboxylate (ZPC) cement showed antibacterial activity against the test organisms. When using DCT, all cements showed some amount of antibacterial activity. Zinc oxide eugenol and ZPC cement showed highest amount of antibacterial activity against S. mutans and L. acidophilus respectively. Within the limitations of study, ZOE cement and ZPC cement were most effective against the tested microorganisms followed by the newer resin cement. The glass ionomer cement was the weakest of all. Patients with high caries index can be treated more effectively using the abovementioned cements.

Vesicular zinc promotes presynaptic and inhibits postsynaptic long term potentiation of mossy fiber-CA3 synapse

PubMed Central

Pan, Enhui; Zhang, Xiao-an; Huang, Zhen; Krezel, Artur; Zhao, Min; Tin-berg, Christine E.; Lippard, Stephen J.; McNamara, James O.

2011-01-01

The presence of zinc in glutamatergic synaptic vesicles of excitatory neurons of mammalian cerebral cortex suggests that zinc might regulate plasticity of synapses formed by these neurons. Long term potentiation (LTP) is a form of synaptic plasticity that may underlie learning and memory. We tested the hypothesis that zinc within vesicles of mossy fibers (mf) contributes to mf-LTP, a classical form of presynaptic LTP. We synthesized an extracellular zinc chelator with selectivity and kinetic properties suitable for study of the large transient of zinc in the synaptic cleft induced by mf stimulation. We found that vesicular zinc is required for presynaptic mf-LTP. Unexpectedly, vesicular zinc also inhibits a novel form of postsynaptic mf-LTP. Because the mf-CA3 synapse provides a major source of excitatory input to the hippocampus, regulating its efficacy by these dual actions of vesicular zinc is critical to proper function of hippocampal circuitry in health and disease. PMID:21943607

Effects of surface hydroxylation on adhesion at zinc/silica interfaces.

PubMed

Le, Ha-Linh Thi; Goniakowski, Jacek; Noguera, Claudine; Koltsov, Alexey; Mataigne, Jean-Michel

2018-06-06

The weak interaction between zinc and silica is responsible for the poor performance of anti-corrosive galvanic zinc coatings on modern advanced high-strength steels, which are fundamental in the automotive industry, and important for rail transport, shipbuilding, and aerospace. With the goal of identifying possible methods for its improvement, we report an ab initio study of the effect of surface hydroxylation on the adhesion characteristics of model zinc/β-cristobalite interfaces, representative of various surface hydroxylation/hydrogenation conditions. We show that surface silanols resulting from dissociative water adsorption at the most stable stoichiometric (001) and (111) surfaces prevent strong zinc-silica interactions. However, dehydrogenation of such interfaces produces oxygen-rich zinc/silica contacts with excellent adhesion characteristics. These are due to partial zinc oxidation and the formation of strong iono-covalent Zn-O bonds between zinc atoms and the under-coordinated excess anions, remnant of the hydroxylation layer. Interestingly, these interfaces appear as the most thermodynamically stable in a wide range of realistic oxygen-rich and hydrogen-lean environments. We also point out that the partial oxidation of zinc atoms in direct contact with the oxide substrate may somewhat weaken the cohesion in the zinc deposit itself. This fundamental analysis of the microscopic mechanisms responsible for the improved zinc wetting on pre-hydroxylated silica substrates provides useful guidelines towards practical attempts to improve adhesion.

Hierarchical Carbon Fibers with ZnO Nanowires for Volatile Sensing in Composite Curing (Postprint)

DTIC Science & Technology

2014-07-01

needed to demonstrate the use of Zinc Oxide (ZnO) nanowire coated carbon fibers as a volatile sensor. ZnO nanowires are demonstrated to function as...processing. For this work, we report on the foundational study needed to demonstrate the use of Zinc Oxide (ZnO) nanowire coated carbon fibers as a...array of ZnO nanowires. Zinc oxide nanowires become more conductive in the presence of ethanol – as analyte sorbs to the surface, electron density

Galvanic zinc-copper microparticles inhibit melanogenesis via multiple pigmentary pathways.

PubMed

Won, Yen-Kim; Lin, Connie B; Seiberg, Miri; Chen, Nannan; Hu, Yaping; Rossetti, Dianne; Saliou, Claude; Loy, Chong-Jin

2014-01-01

The endogenous electrical field of human skin plays an important role in many skin functions. However, the biological effects and mechanism of action of externally applied electrical stimulation on skin remain unclear. Recent study showed that galvanic zinc-copper microparticles produce electrical stimulation and reduce inflammatory and immune responses in intact skin, suggesting the important role of electrical stimulation in non-wounded skin. The objective of this study is to investigate the biological effect of galvanic zinc-copper microparticles on skin pigmentation. Our findings showed that galvanic zinc-copper microparticles inhibited melanogenesis in a human melanoma cell line (MNT-1), human keratinocytes and melanoma cells co-cultures, and in pigmented epidermal equivalents. Treatment of galvanic zinc-copper microparticles inhibited melanogenesis by reducing the promoter transactivation of tyrosinase and tyrosinase-related protein-1 in human melanoma cells. In a co-culture Transwell system of keratinocytes and melanoma cells, galvanic zinc-copper microparticles reduced melanin production via downregulation of endothelin-1 secretion from keratinocytes and reduced tyrosinase gene expression in melanoma cells. In addition, exposure of pigmented epidermal equivalents to galvanic zinc-copper microparticles resulted in reduced melanin deposition. In conclusion, our data demonstrated for the first time that galvanic zinc-copper microparticles reduced melanogenesis in melanoma cells and melanin deposition in pigmented epidermal equivalents by affecting multiple pigmentary pathways.

Inhibition effects of protein-conjugated amorphous zinc sulfide nanoparticles on tumor cells growth

NASA Astrophysics Data System (ADS)

Cao, Ying; Wang, Hua-Jie; Cao, Cui; Sun, Yuan-Yuan; Yang, Lin; Wang, Bao-Qing; Zhou, Jian-Guo

2011-07-01

In this article, a facile and environmentally friendly method was applied to fabricate BSA-conjugated amorphous zinc sulfide (ZnS) nanoparticles using bovine serum albumin (BSA) as the matrix. Transmission electron microscopy analysis indicated that the stable and well-dispersed nanoparticles with the diameter of 15.9 ± 2.1 nm were successfully prepared. The energy dispersive X-ray, X-ray powder diffraction, Fourier transform infrared spectrograph, high resolution transmission electron microscope, and selected area electron diffraction measurements showed that the obtained nanoparticles had the amorphous structure and the coordination occurred between zinc sulfide surfaces and BSA in the nanoparticles. In addition, the inhibition effects of BSA-conjugated amorphous zinc sulfide nanoparticles on tumor cells growth were described in detail by cell viability analysis, optical and electron microscopy methods. The results showed that BSA-conjugated amorphous zinc sulfide nanoparticles could inhibit the metabolism and proliferation of human hepatocellular carcinoma cells, and the inhibition was dose dependent. The half maximal inhibitory concentration (IC50) was 0.36 mg/mL. Overall, this study suggested that BSA-conjugated amorphous zinc sulfide nanoparticles had the application potential as cytostatic agents and BSA in the nanoparticles could provide the modifiable site for the nanoparticles to improve their bioactivity or to endow them with the target function.

Disruption of redox catalytic functions of peroxiredoxin-thioredoxin complex in Mycobacterium tuberculosis H37Rv using small interface binding molecules.

PubMed

Gurung, Arun Bahadur; Das, Amit Kumar; Bhattacharjee, Atanu

2017-04-01

Mycobacterium tuberculosis has distinctive ability to detoxify various microbicidal superoxides and hydroperoxides via a redox catalytic cycle involving thiol reductants of peroxiredoxin (Prx) and thioredoxin (Trx) systems which has conferred on it resistance against oxidative killing and survivability within host. We have used computational approach to disrupt catalytic functions of Prx-Trx complex which can possibly render the pathogen vulnerable to oxidative killing in the host. Using protein-protein docking method, we have successfully constructed the Prx-Trx complex. Statistics of interface region revealed contact area of each monomer less than 1500Å 2 and enriched in polar amino acids indicating transient interaction between Prx and Trx. We have identified ZINC40139449 as a potent interface binding molecule through virtual screening of drug-like compounds from ZINC database. Molecular dynamics (MD) simulation studies showed differences in structural properties of Prx-Trx complex both in apo and ligand bound states with regard to root mean square deviation (RMSD), radius of gyration (Rg), root mean square fluctuations (RMSF), solvent accessible surface area (SASA) and number of hydrogen bonds (NHBs). Interestingly, we found stability of two conserved catalytic residues Cys61 and Cys174 of Prx and conserved catalytic motif, WCXXC of Trx upon binding of ZINC40139449. The time dependent displacement study reveals that the compound is quite stable in the interface binding region till 30ns of MD simulation. The structural properties were further validated by principal component analysis (PCA). We report ZINC40139449 as promising lead which can be further evaluated by in vitro or in vivo enzyme inhibition assays. Copyright © 2016 Elsevier Ltd. All rights reserved.

Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity

PubMed Central

Lin, Cun; Hara, Ayaka; Comparini, Diego; Bouteau, François; Kawano, Tomonori

2015-01-01

Al3+ toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al3+ toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn2+ against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn2+ interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn2+ on Al3+-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn2+-dependent inhibition of the Al3+-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al3+/Zn2+ interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn2+ at physiological concentrations can protect the cells by preventing the Al3+-induced superoxide generation and cell death. Furthermore, the regulation of the Ca2+ signaling, i.e., change in the cytosolic Ca2+ ion concentration, and the cross-talks among the elements which participate in the pathway were further explored. PMID:26648960

Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

Improved Sp1 and Betaine Homocysteine-S-Methyltransferase Expression and Homocysteine Clearance Are Involved in the Effects of Zinc on Oxidative Stress in High-Fat-Diet-Pretreated Mice.

PubMed

Wu, Li; Zhou, Xihong; Li, Tiejun; He, Juyun; Huang, Linli; Ouyang, Zicheng; He, Liuqin; Wei, Tao; He, Qinghua

2017-12-04

Zinc plays a role in alleviating oxidative stress. However, the related mechanisms remain to be further elucidated. The present study was conducted to investigate whether the recovery of oxidative stress in high-fat-diet (HFD)-pretreated mice was affected by zinc. Male mice received either an HFD or a low-fat-diet (LFD) for 8 weeks. Then, the mice fed with HFD and LFD were both assigned to either a control diet (30 mg zinc, ZD) or a no-added zinc diet (NZD) for an additional 4 weeks. The results showed that after feeding with NZD for 4 weeks, the HFD-pretreated mice had the highest plasma glucose and insulin concentrations, while had the lowest CuZn-SOD and glutathione concentrations. Moreover, after feeding with NZD for 4 weeks, the HFD-pretreated mice had the highest hepatic ROS and homocysteine concentrations, while had the lowest glutathione and methionine concentrations. Furthermore, the HFD-pretreated mice fed with NZD for 4 weeks had the lowest gene and protein expression of betaine homocysteine-S-methyltransferase (BHMT), cystathionine β-synthase, and Sp1. The results suggested that zinc was critical for oxidative stress alleviation and homocysteine clearance in HFD-pretreated mice. It was further elucidated that improved Sp1 and BHMT expression are involved in the effects of zinc on oxidative stress.

Leaching with Penicillium simplicissimum: Influence of metals and buffers on proton extrusion and citric acid production

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

Franz, A.; Burgstaller, W.; Schinner, F.

1991-03-01

In the presence of insoluble metal oxides (industrial filter dust, zinc oxide, synthetic mixture of metal oxides), Penicillium simplicissimum developed the ability to excrete considerable amounts of citric acid (>100 mM). Parallel with the increase of citric acid concentration in the culture broth, zinc was solubilized from zinc oxide. The adsorption of filter dust onto the mycelium (the pellets formed were less than 1 mm in diameter) was required for not only the citric acid excretion but also the leaching of zinc. When the filter dust was replaced with a synthetic mixture of metal oxides or with zinc oxide inmore » combination with trace elements, levels of adsorption and citric acid production were observed to be similar to those in experiments where industrial filter dust was used. The two most important properties of the filter dust were its heavy-metal content and its buffering capacity. These properties were simulated by adding heavy metals in soluble form (as chlorides, sulfates, or nitrates) or soluble buffers to the medium. Both heavy metals and buffers were not able to induce a citric acid efflux. As with citric acid production by Aspergillus niger, the addition of manganese lowered citric acid excretion (by 40% with metal oxide-induced citric acid efflux and by 100% with urea-induced citric acid efflux). Copper antagonized the effect of manganese. The mechanism for the bulk of citric acid excretion by P. simplicissimum, however, seemed to be different from that described for citric acid accumulation by A. niger. Because of the inefficiency of metals in solubilized form and of soluble buffers to induce a strong citric acid efflux, adsorption of an insoluble metal compound (zinc oxide) turned out to be essential.« less

Preparation of Diatomite Supported Nano Zinc Oxide Composite Photocatalytic Material and Study on its Formaldehyde Degradation

NASA Astrophysics Data System (ADS)

Xiao, Liguang; Pang, Bo

2017-09-01

This experiment used zinc nitrate as precursor, ethanol as solvent and polyethylene glycol as dispersant, diatomite as carrier, diatomite loaded nano Zinc Oxide was prepared by sol-gel method, in addition, the formaldehyde degradation was studied by two kinds of experimental methods: preparation and loading, preparation and post loading, The samples were characterized by SEM, XRD, BET and IR. Experimental results showed that: Diatomite based nano Zinc Oxide had a continuous adsorption and degradation of formaldehyde, formaldehyde gas with initial concentration was 0.7mg/m3, after 36h degradation, the concentration reached 0.238mg/m3, the degradation rate reached to 66%.

Purifying Properly Folded Cysteine-rich, Zinc Finger Containing Recombinant Proteins for Structural Drug Targeting Studies: the CH1 Domain of p300 as a Case Example

PubMed Central

Kim, Yong Joon; Kaluz, Stefan; Mehta, Anil; Weinert, Emily; Rivera, Shannon; Van Meir, Erwin G.

2017-01-01

The transcription factor Hypoxia-Inducible Factor (HIF) complexes with the coactivator p300, activating the hypoxia response pathway and allowing tumors to grow. The CH1 and CAD domains of each respective protein form the interface between p300 and HIF. Small molecule compounds are in development that target and inhibit HIF/p300 complex formation, with the goal of reducing tumor growth. High resolution NMR spectroscopy is necessary to study ligand interaction with p300-CH1, and purifying high quantities of properly folded p300-CH1 is needed for pursuing structural and biophysical studies. p300-CH1 has 3 zinc fingers and 9 cysteine residues, posing challenges associated with reagent compatibility and protein oxidation. A protocol has been developed to overcome such issues by incorporating zinc during expression and streamlining the purification time, resulting in a high yield of optimally folded protein (120 mg per 4 L expression media) that is suitable for structural NMR studies. The structural integrity of the final recombinant p300-CH1 has been verified to be optimal using onedimensional 1H NMR spectroscopy and circular dichroism. This protocol is applicable for the purification of other zinc finger containing proteins. PMID:28966947

Stable White Coatings

NASA Technical Reports Server (NTRS)

Zerlaut, Gene A.; Gilligan, J. E.; Harada, Y.

1965-01-01

In a previous research program for the Jet Propulsion- Laboratory, extensive studies led to the development and specifications of three zinc oxide-pigmented thermal-control coatings. The principal objectives of this program are: improvement of the three paints (as engineering materials), determination of the validity of our accelerated space-simulation testing, and continuation of the zinc oxide photolysis studies begun in the preceding program. Specific tasks that are discussed include: improvement of potassium silicate coatings as engineering materials and elucidation of their storage and handling problems; improvement of methyl silicone coatings as engineering materials; studies of zinc oxide photolysis to establish reasons for the observed stability of zinc oxide; and determination of space-simulation parameters such as long-term stability (to 8000 ESH), effect of coating surface temperature on the rate of degradation, and validity of accelerated testing (by reciprocity and wavelength dependency studies).

Study on the pre-treatment of oxidized zinc ore prior to flotation

NASA Astrophysics Data System (ADS)

He, Dong-sheng; Chen, Yun; Xiang, Ping; Yu, Zheng-jun; Potgieter, J. H.

2018-02-01

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

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

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

PubMed

Nagarajan, Sangeetha; Arumugam Kuppusamy, Kumaraguru

2013-12-03

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. 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. 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.

[Effect of Cu2+ and Zn2+ ions in Ca-ATPase activity isolated from Pachymerus nucleorum (Fabricius) (Coleoptera: Chrysomelidae, Bruchinae) larvae].

PubMed

Dias, Decivaldo S; Coelho, Milton V

2007-01-01

ATPases, an important target of insecticides, are enzymes that hydrolyze ATP and use the energy released in that process to accomplish some type of cellular work. Pachymerus nucleorum (Fabricius) larvae possess an ATPase, that presents high Ca-ATPase activity, but no Mg-ATPase activity. In the present study, the effect of zinc and copper ions in the activity Ca-ATPase of that enzyme was tested. More than 90% of the Ca-ATPase activity was inhibited in 0.5 mM of copper ions or 0.25 mM of zinc ions. In the presence of EDTA, but not in the absence, the inhibition by zinc was reverted with the increase of calcium concentration. The inhibition by copper ions was not reverted in the presence or absence of EDTA. The Ca-ATPase was not inhibited by treatment of the ATPase fraction with copper, suggesting that the copper ion does not bind directly to the enzyme. The results suggest that zinc and copper ions form a complex with ATP and bind to the enzyme inhibiting its Ca-ATPase activity.

Protective effect of zinc against ischemic neuronal injury in a middle cerebral artery occlusion model.

PubMed

Kitamura, Youji; Iida, Yasuhiko; Abe, Jun; Ueda, Masashi; Mifune, Masaki; Kasuya, Fumiyo; Ohta, Masayuki; Igarashi, Kazuo; Saito, Yutaka; Saji, Hideo

2006-02-01

In this study, we investigated the effect of vesicular zinc on ischemic neuronal injury. In cultured neurons, addition of a low concentration (under 100 microM) of zinc inhibited both glutamate-induced calcium influx and neuronal death. In contrast, a higher concentration (over 150 microM) of zinc decreased neuronal viability, although calcium influx was inhibited. These results indicate that zinc exhibits biphasic effects depending on its concentration. Furthermore, in cultured neurons, co-addition of glutamate and CaEDTA, which binds extra-cellular zinc, increased glutamate-induced calcium influx and aggravated the neurotoxicity of glutamate. In a rat transient middle cerebral artery occlusion (MCAO) model, the infarction volume, which is related to the neurotoxicity of glutamate, increased rapidly on the intracerebral ventricular injection of CaEDTA 30 min prior to occlusion. These results suggest that zinc released from synaptic vesicles may provide a protective effect against ischemic neuronal injury.

Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets

PubMed Central

Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

2013-01-01

Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

Down-top nanofabrication of binary (CdO)x (ZnO)1-x nanoparticles and their antibacterial activity.

PubMed

Al-Hada, Naif Mohammed; Mohamed Kamari, Halimah; Abdullah, Che Azurahanim Che; Saion, Elias; Shaari, Abdul H; Talib, Zainal Abidin; Matori, Khamirul Amin

2017-01-01

In the present study, binary oxide (cadmium oxide [CdO]) x (zinc oxide [ZnO]) 1-x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO) x (ZnO) 1-x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO) x (ZnO) 1-x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO) x (ZnO) 1-x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precursor increased from x=0.20 to x=0.80, as observed by TEM results. The surface composition and valance state of the prepared product NPs were determined by X-ray photoelectron spectroscopy (XPS) analyses. Diffuse UV-visible reflectance spectra were used to determine the optical band gap through the Kubelka-Munk equation; the energy band gap was found to decrease for CdO from 2.92 to 2.82 eV and for ZnO from 3.22 to 3.11 eV with increasing x value. Additionally, photoluminescence (PL) spectra revealed that the intensity in PL increased with an increase in particle size. In addition, the antibacterial activity of binary oxide NP was carried out in vitro against Escherichia coli ATCC 25922 Gram (-ve), Salmonella choleraesuis ATCC 10708, and Bacillus subtilis UPMC 1175 Gram (+ve). This study indicated that the zone of inhibition of 21 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175.

In-vitro efficacy of different morphology zinc oxide nanopowders on Streptococcus sobrinus and Streptococcus mutans.

PubMed

Mohd Bakhori, Siti Khadijah; Mahmud, Shahrom; Ling, Chuo Ann; Sirelkhatim, Amna Hassan; Hasan, Habsah; Mohamad, Dasmawati; Masudi, Sam'an Malik; Seeni, Azman; Abd Rahman, Rosliza

2017-09-01

ZnO with two different morphologies were used to study the inhibition of Streptococcus sobrinus and Streptococcus mutans which are closely associated with tooth cavity. Rod-like shaped ZnO-A and plate-like shaped ZnO-B were produced using a zinc boiling furnace. The nanopowders were characterized using energy filtered transmission electron microscopy (EFTEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, Raman spectroscopy and dynamic light scattering (DLS) to confirm the properties of the ZnO polycrystalline wurtzite structures. XRD results show that the calculated crystallite sizes of ZnO-A and ZnO-B were 36.6 and 39.4nm, respectively, whereas DLS revealed particle size distributions of 21.82nm (ZnO-A) and 52.21nm (ZnO-B). PL spectra showed ion vacancy defects related to green and red luminescence for both ZnO particles. These defects evolved during the generation of reactive oxygen species which contributed to the antibacterial activity. Antibacterial activity was investigated using microdilution technique towards S. sobrinus and S. mutans at different nanopowder concentrations. Results showed that ZnO-A exhibited higher inhibition on both bacteria compared with ZnO-B. Moreover, S. mutans was more sensitive compared with S. sobrinus because of its higher inhibition rate. Copyright © 2017 Elsevier B.V. All rights reserved.

Zinc Supplementation Ameliorates Diabetic Cataract Through Modulation of Crystallin Proteins and Polyol Pathway in Experimental Rats.

PubMed

Barman, Susmita; Srinivasan, Krishnapura

2018-05-13

Non-enzymatic glycation of lens proteins and elevated polyol pathway in the eye lens have been the characteristic features of a diabetic condition. We have previously reported the benefits of zinc supplementation in reducing hyperglycemia and associated metabolic abnormalities and oxidative stress in diabetic rats. The current study explored whether zinc supplementation protects against cataractogenesis through modulation of glycation of lens proteins, elevated polyol pathway, oxidative stress, and proportion of different heat shock proteins in the eye lens of diabetic rats. Streptozotocin-induced diabetic rats were fed with a zinc-enriched diet (5 and 10 times of normal) for 6 weeks. Supplemental zinc alleviated the progression and maturation of diabetes-induced cataract. Zinc was also effective in preventing the reduced content of total and imbalanced proportion of soluble proteins in the lens. Supplemental zinc also alleviated cross-linked glycation and concomitant expression of the receptor of glycated products and oxidative stress indicators in the eye lens. Zinc supplementation further induced the concentration of heat shock protein in the eye lens of diabetic rats, specifically α-crystallin. Zinc supplementation counteracted the elevated activity and expression of polyol pathway enzymes and molecules in the lens. The results of this animal study endorsed the advantage of zinc supplementation in exerting the antiglycating influence and downregulating polyol pathway enzymes to defer cataractogenesis in diabetic rats.

Chiral mercaptoacetamides display enantioselective inhibition of histone deacetylase 6 and exhibit neuroprotection in cortical neuron models of oxidative stress.

PubMed

Kalin, Jay H; Zhang, Hankun; Gaudrel-Grosay, Sophie; Vistoli, Giulio; Kozikowski, Alan P

2012-03-05

Mercaptoacetamide-based ligands have been designed as a new class of histone deacetylase (HDAC) inhibitors for possible use in the treatment of neurodegenerative diseases. The thiol group of these compounds provides a key binding element for interaction with the catalytic zinc ion, and thus differs from the more typically employed hydroxamic acid based zinc binding groups. Herein we disclose the chemistry and biology of some substituted mercaptoacetamides with the intention of increasing HDAC6 isoform selectivity while maintaining potency similar to their hydroxamic acid analogues. The introduction of a stereocenter α to the thiol group was found to have a considerable impact on HDAC inhibitor potency. These new compounds were also profiled for their therapeutic potential in an in vitro model of stress-induced neuronal injury and were found to act as nontoxic neuroprotective agents. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effects of cetyltrimethylammonium bromide surfactant on alumina modified zinc oxides

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

Gac, Wojciech, E-mail: wojciech.gac@umcs.lublin.pl; Zawadzki, Witold; Słowik, Grzegorz

Highlights: • Synthesis of novel ZnO−Al{sub 2}O{sub 3} oxides in the presence of CTAB surfactant. • Determination of the structural, surface and optical properties. • Nanocrystalline, high-surface area ZnO−Al{sub 2}O{sub 3} oxides. • ZnO-Al{sub 2}O{sub 3} materials of different gap energy. - Abstract: Novel alumina modified zinc oxide materials were prepared by co-precipitation method in the presence of different amounts of cetyltrimethylammonium bromide (CTAB) surfactant. X-ray diffraction, {sup 27}Al magic-angle spinning Nuclear Magnetic Resonance Spectroscopy, and transmission electron microscopy studies evidenced formation of 10–15 nm zinc oxide nanoparticles in the presence of the small amounts of surfactant. Amorphous alumina andmore » zinc aluminate phases of different coordination environment of Al sites were identified. An increase of surfactant concentration led to the elongation of nanoparticles and changes of the nature of hydroxyl groups. Precipitation in the high CTAB concentration conditions facilitated formation of mesoporous materials of high specific surface area. The materials were composed of very small (2–3 nm) zinc aluminate spinel nanoparticles. High concentration of CTAB induced widening of band gap energy.« less

Clinical and radiographic evaluation of zinc oxide with aloe vera as an obturating material in pulpectomy: an in vivo study.

PubMed

Khairwa, Abhishek; Bhat, Manohar; Sharma, Rajesh; Satish, V; Maganur, Prabhadevi; Goyal, Anil Kumar

2014-01-01

Pulp therapy for pulpally involved primary teeth continues to be a challenge to clinicians. One of the major areas of continued research is in the area of finding obturating materials to suit the specific properties of these teeth. Zinc oxide eugenol is used frequently in pulpectomy for the obturation of the primary teeth. To evaluate clinically and radiographically a mixture of zinc oxide eugenol and aloe vera as an obturating material. A total of 50 children, aged between 4 and 9 years, who were screened for unilateral or bilateral carious deciduous molars were studied. Out of these, 15 children were randomly selected for endodontic treatment. Obturation was done with a mixture of zinc oxide powder and aloe vera gel. Clinical and radiographic evaluation was done after 7 days, 1 month, 3 months, 6 months, and 9 months. The data were statistically analyzed. Endodontic treatment using a mixture of zinc oxide powder and aloe vera gel in primary teeth has shown good clinical and radiographic success. A detailed observational study with longer follow-up will highlight the benefits of aloe vera in primary teeth as an obturating medium.

Quantifying charge carrier concentration in ZnO thin films by Scanning Kelvin Probe Microscopy

PubMed Central

Maragliano, C.; Lilliu, S.; Dahlem, M. S.; Chiesa, M.; Souier, T.; Stefancich, M.

2014-01-01

In the last years there has been a renewed interest for zinc oxide semiconductor, mainly triggered by its prospects in optoelectronic applications. In particular, zinc oxide thin films are being widely used for photovoltaic applications, in which the determination of the electrical conductivity is of great importance. Being an intrinsically doped material, the quantification of its doping concentration has always been challenging. Here we show how to probe the charge carrier density of zinc oxide thin films by Scanning Kelvin Probe Microscopy, a technique that allows measuring the contact potential difference between the tip and the sample surface with high spatial resolution. A simple electronic energy model is used for correlating the contact potential difference with the doping concentration in the material. Limitations of this technique are discussed in details and some experimental solutions are proposed. Two-dimensional doping concentration images acquired on radio frequency-sputtered intrinsic zinc oxide thin films with different thickness and deposited under different conditions are reported. We show that results inferred with this technique are in accordance with carrier concentration expected for zinc oxide thin films deposited under different conditions and obtained from resistivity and mobility measurements. PMID:24569599

Local anesthetic lidocaine inhibits TRPM7 current and TRPM7-mediated zinc toxicity.

PubMed

Leng, Tian-Dong; Lin, Jun; Sun, Hua-Wei; Zeng, Zhao; O'Bryant, Zaven; Inoue, Koichi; Xiong, Zhi-Gang

2015-01-01

Previous study demonstrated that overstimulation of TRPM7 substantially contributes to zinc-mediated neuronal toxicity. Inhibition of TRPM7 activity and TRPM7-mediated intracellular Zn(2+) accumulation may represent a promising strategy in the treatment of stroke. To investigate whether local anesthetics lidocaine could inhibit TRPM7 channel and TRPM7-mediated zinc toxicity. Whole-cell patch-clamp technique was used to investigate the effect of local anesthetics on TRPM7 currents in cultured mouse cortical neurons and TRPM7-overexpressed HEK293 cells. Fluorescent Zn(2+) imaging technique was used to study the effect of lidocaine on TRPM7-mediated intracellular Zn(2+) accumulation. TRPM7-mediated zinc toxicity in neurons was used to evaluate the neuroprotective effect of lidocaine. (1) Lidocaine dose dependently inhibits TRPM7-like currents, with an IC50 of 11.55 and 11.06 mM in cultured mouse cortical neurons and TRPM7-overexpressed HEK293 cells, respectively; (2) Lidocaine inhibits TRPM7 currents in a use/frequency-dependent manner; (3) Lidocaine inhibits TRPM7-mediated intracellular Zn(2+) accumulation in both cortical neurons and TRPM7-overexpressed HEK293 cells; (4) TRPM7-mediated Zn(2+) toxicity is ameliorated by lidocaine in cortical neurons; (5) QX-314 has a similar inhibitory effect as lidocaine on TRPM7 currents when applied extracellularly; (6) Procaine also shows potent inhibitory effect on the TRPM7 currents in cortical neurons. Our data provide the first evidence that local anesthetic lidocaine inhibits TRPM7 channel and TRPM7-mediated zinc toxicity. © 2014 John Wiley & Sons Ltd.

Respiratory Symptoms and Pulmonary Function Tests among Galvanized Workers Exposed To Zinc Oxide.

PubMed

Aminian, Omid; Zeinodin, Hamidreza; Sadeghniiat-Haghighi, Khosro; Izadi, Nazanin

2015-01-01

Galvanization is the process of coating steel or cast iron pieces with a thin layer of zinc allowing protection against corrosion. One of the important hazards in this industry is exposure to zinc compounds specially zinc oxide fumes and dusts. In this study, we evaluated chronic effects of zinc oxide on the respiratory tract of galvanizers. Overall, 188 workers were selected from Arak galvanization plant in 2012, 71 galvanizers as exposed group and 117 workers from other departments of plants as control group. Information was collected using American Thoracic Society (ATS) standard questionnaire, physical examination and demographic data sheet. Pulmonary function tests were measured for all subjects. Exposure assessment was done with NIOSH 7030 method. The Personal Breathing Zone (PBZ) air sampling results for zinc ranged from 6.61 to 8.25 mg/m³ above the permissible levels (Time weighted average; TWA:2 mg/m³). The prevalence of the respiratory symptoms such as dyspnea, throat and nose irritation in the exposed group was significantly (P<0.01) more than the control group. Decreasing in average percent in all spirometric parameters were seen in the galvanizers who exposed to zinc oxide fumes and dusts. The prevalence of obstructive respiratory disease was significantly (P=0.034) higher in the exposed group. High workplace zinc levels are associated with an increase in respiratory morbidity in galvanizers. Therefore administrators should evaluate these workers with periodic medical examinations and implement respiratory protection program in the working areas.

Acrosin activity in turkey spermatozoa: assay by clinical method and effect of zinc and benzamidine on the activity.

PubMed

Glogowski, J; Jankowski, J; Faruga, A; Ottobre, J S; Ciereszko, A

2001-09-15

We optimized a clinical assay developed for measuring total acrosin activity for mammalian and fish semen for use in turkey spermatozoa. The main modifications included dilution of semen to a final concentration of 25 to 1000 x 10(3) spermatozoa, an increase of Triton X-100 concentration to 0.05% and 1 hr preincubation without substrate, Acrosin activity in turkey spermatozoa was much higher than in human spermatozoa (about 100-times) but similar to that of boar sperm. To optimize this assay for turkey spermatozoa, it was necessary to use higher Triton X-100 concentrations in the reaction mixture. There was a better catalytic efficiency at higher temperatures and a special requirement for a preincubation period for proacrosin activation. We observed high inhibition of acrosin activity by zinc added during preincubation (90% at 0.01 mM of zinc chloride). Benzamidine also inhibited turkey acrosin, and the extent of inhibition was similar for the incubation or preincubation period. When zinc ions were added during incubation, this inhibition was lower (24%). The results suggest that zinc influences proacrosin activation of turkey spermatozoa. This influence may be important for successful long-term storage of spermatozoa in the hen's oviduct.

Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

PubMed

Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

2012-01-17

Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions. © 2011 American Chemical Society

Effect of the temperature on structural and optical properties of zinc oxide nanoparticles.

PubMed

Hadia, N M A; García-Granda, Santiago; García, José R

2014-07-01

Zinc nitrate hexahydrate, Zn(NO3)2 x 6H2O was used as a precursor with urea NH2CONH2 to prepare hydrozincite Zn5(CO3)2(OH)6 powder using hydrothermal method for 8 h at 90 degrees C. Zinc oxide (ZnO) nanoparticles (NPs) were prepared by thermal annealing of hydrozincite powder at different annealing temperatures, i.e., 350, 550 750 and 950 degrees C in air for 2 h. The resulting materials were characterized by X-ray diffraction, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The optical properties of the products were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and photoluminescence (PL) spectra. It was found that the particle size increased from - 33 to 250 nm with increasing in the annealing temperatures. FTIR results showed that the standard peaks of zinc oxide were presented at 428.17 and 532.32 cm(-1). Thermal analysis study showed that the primary weight loss starts at - 93 degrees C is due to solvent evaporation. The secondary weight loss, observed at - 378 degrees C, is due to phase transition from hydrated zinc oxide to zinc oxide. The band gaps of the products were in the range - 3.26-3.30 eV. The PL spectrum showed that the as-synthesized ZnO nanoparticles had UV (381 nm) and green (537 nm) emissions.

Quantum dots conjugated zinc oxide nanosheets: Impeder of microbial growth and biofilm

NASA Astrophysics Data System (ADS)

Patil, Rajendra; Gholap, Haribhau; Warule, Sambhaji; Banpurkar, Arun; Kulkarni, Gauri; Gade, Wasudeo

2015-01-01

The grieving problem of the 21st century has been the antimicrobial resistance in pathogenic microorganisms to conventional antibiotics. Therefore, developments of novel antibacterial materials which effectively inhibit or kill such resistant microorganisms have become the need of the hour. In the present study, we communicate the synthesis of quantum dots conjugated zinc oxide nanostructures (ZnO/CdTe) as an impeder of microbial growth and biofilm. The as-synthesized nanostructures were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy. The growth impedance property of ZnO and ZnO/CdTe on Gram positive organism, Bacillus subtilis NCIM 2063 and Gram negative, Escherichia coli NCIM 2931 and biofilm impedance activity in Pseudomonas aeruginosa O1 was found to occur due to photocatalytical action on the cell biofilm surfaces. The impedance in microbial growth and biofilm formation was further supported by ruptured appearances of cells and dettrered biofilm under field emission scanning electron and confocal laser scanning microscope. The ZnO/CdTe nanostructures array synthesized by hydrothermal method has an advantage of low growth temperature, and opportunity to fabricate inexpensive material for nano-biotechnological applications.

The Effect of UV Aging on Antimicrobial and Mechanical Properties of PLA Films with Incorporated Zinc Oxide Nanoparticles

PubMed Central

Mizielińska, Małgorzata; Kowalska, Urszula; Jarosz, Michał; Sumińska, Patrycja; Landercy, Nicolas; Duquesne, Emmanuel

2018-01-01

The aim of this study was to examine the influence of accelerated UV-aging on the activity against chosen microorganisms and the mechanical properties of poly-lactic acid (PLA) films enhanced with ZnO nanoparticles. The pure PLA films and tri-layered PLAZnO1%/PLA/PLAZnO1% films of 150 µm thickness were extruded. The samples were treated with UV-A and Q-SUN irradiation. After irradiation the antimicrobial activity and mechanical properties of the films were analyzed. The results of the study demonstrated that PLA films did not inhibit the growth of Staphylococcus aureus, Bacillus cereus, Escherichia coli, Bacillus atrophaeus, and Candida albicans cells. PLA films with incorporated zinc oxide nanoparticles decreased the number of analyzed microorganisms. Accelerated UV aging had no negative effect on the activity of the film containing nano-ZnO against Gram-positive bacteria, but it influenced the activity against Gram-negative cells and C. albicans. Q-SUN irradiation decreased the antimicrobial effect of films with incorporated nanoparticles against B. cereus. UV-A and Q-UV irradiation did not influence the mechanical properties of PLA films containing incorporated ZnO nanoparticles. PMID:29670066

The Effect of UV Aging on Antimicrobial and Mechanical Properties of PLA Films with Incorporated Zinc Oxide Nanoparticles.

PubMed

Mizielińska, Małgorzata; Kowalska, Urszula; Jarosz, Michał; Sumińska, Patrycja; Landercy, Nicolas; Duquesne, Emmanuel

2018-04-18

The aim of this study was to examine the influence of accelerated UV-aging on the activity against chosen microorganisms and the mechanical properties of poly-lactic acid (PLA) films enhanced with ZnO nanoparticles. The pure PLA films and tri-layered PLAZnO1%/PLA/PLAZnO1% films of 150 µm thickness were extruded. The samples were treated with UV-A and Q-SUN irradiation. After irradiation the antimicrobial activity and mechanical properties of the films were analyzed. The results of the study demonstrated that PLA films did not inhibit the growth of Staphylococcus aureus , Bacillus cereus , Escherichia coli , Bacillus atrophaeus , and Candida albicans cells. PLA films with incorporated zinc oxide nanoparticles decreased the number of analyzed microorganisms. Accelerated UV aging had no negative effect on the activity of the film containing nano-ZnO against Gram-positive bacteria, but it influenced the activity against Gram-negative cells and C. albicans . Q-SUN irradiation decreased the antimicrobial effect of films with incorporated nanoparticles against B. cereus . UV-A and Q-UV irradiation did not influence the mechanical properties of PLA films containing incorporated ZnO nanoparticles.

Characterization of Antimicrobial Poly (Lactic Acid)/Nano-Composite Films with Silver and Zinc Oxide Nanoparticles

PubMed Central

Chu, Zhuangzhuang; Zhao, Tianrui; Li, Lin; Fan, Jian; Qin, Yuyue

2017-01-01

Antimicrobial active films based on poly (lactic acid) (PLA) were prepared with nano-silver (nano-Ag) and nano-zinc oxide (nano-ZnO) using a solvent volatilizing method. The films were characterized for mechanical, structural, thermal, physical and antimicrobial properties. Scanning electron microscopy (SEM) images characterized the fracture morphology of the films with different contents of nano-Ag and nano-ZnO. The addition of nanoparticles into the pure PLA film decreased the tensile strength and elasticity modulus and increased the elongation of breaks—in other words, the flexibility and extensibility of these composites improved. According to the results of differential scanning calorimetry (DSC), the glass transition temperature of the PLA nano-composite films decreased, and the crystallinity of these films increased; a similar result was apparent from X-ray diffraction (XRD) analysis. The water vapor permeability (WVP) and opacity of the PLA nano-composite films augmented compared with pure PLA film. Incorporation of nanoparticles to the PLA films significantly improved the antimicrobial activity to inhibit the growth of Escherichia coli. The results indicated that PLA films with nanoparticles could be considered a potential environmental-friendly packaging material. PMID:28773018

Involvement of l-arginine-nitric oxide pathway in anxiolytic-like effects of zinc chloride in rats.

PubMed

Navabi, Seyedeh Parisa; Eshagh Harooni, Hooman; Moazedi, Ahmad Ali; Khajepour, Lotfolah; Fathinia, Kosar

2016-10-01

Zinc is crucial for normal development of the brain, and Zinc deficiency has been shown to associate with neurological disorders (e.g. anxiety) through interactions with several neurotransmitter systems such as nitric oxide (NO). In this regard, our study aimed to evaluate the possible involvement of l-arginine NO pathway on anxiolytic effects of zinc in adult male rats. Zinc chloride at doses of 2.5 and 10mg/kg (intraperitoneal or ip) or saline (1ml/kg, ip) were injected 30min before the anxiety test. Zinc administrated rats (10mg/kg) were pre-treated with intra-CA1 microinjection of l-arginine in sub-effective dose of 1μg/rat (dorsal hippocampus, vehicle: saline1μl/rat). In addition, zinc chloride and NG-nitro-l-arginine methyl ester (l-NAME) were intraperitoneally co-administrated in sub-effective doses of 2.5mg/kg and 80mg/kg, respectively. The percentage of open arm time (OAT%), percentage of open arm entry (OAE%), as measures of anxiety, and total number of arm entries, as measures of locomotor activity, were recorded. Treatment with zinc (10mg/kg) markedly produced an increase in OAT% and OAE% in the Elevated plus maze test (EPM). A decrease of OAT% and OAE% was shown in groups which received zinc (10mg/kg) and l-arginine (1μg/rat) concomitantly as compared to the control group. Moreover, an increase of OAE% was revealed in the group exposed to Zinc (2.5mg/kg) and l-NAME (80mg/kg) co-administration. Although, Two-way ANOVA showed no significant differences of anxiety indices in rats received drug+zinc chloride in compare to the zinc pretreated with saline group. Anxiolytic- like effect of zinc reversed by nitric oxide precursor l-arginine. Additionally, the synergistic effects of l-NAME and ZnCl 2 were shown in the EPM. Thus our findings suggest that at least in part the anxiolytic effects of zinc can be mediated through the nitric oxide system. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Ultrasonic measurements of thin zinc layers on concrete

NASA Astrophysics Data System (ADS)

Jansen, Henri; Brooks, Bill; Nguyen, Vinh; Koretsky, Milo

2008-05-01

In order to protect bridges at the coast from corrosion, a thin layer (approximately 0.5 mm) of zinc is sprayed on the concrete of the bridge. When this zinc layer is electrically connected to the reinforcing steel (rebar) and placed at a positive potential with respect to the rebar, oxidation is favored at the zinc layer and reduced at the rebar. The resulting protection of the rebar fails when the zinc layer delaminates from the concrete or when the zinc oxidation product layer becomes too thick. We have used ultrasonic detection to investigate the properties of the zinc layer. This method has been applied very successfully in the semiconductor industry. We present the details of the method and the expected response. Unfortunately, we are not able to measure changes in the zinc layer, because either the frequency we use (10-20 MHz) is too low, or scattering in the concrete is a dominant effect.

40 CFR 60.171 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Primary Zinc Smelters § 60.171 Definitions... and in subpart A of this part. (a) Primary zinc smelter means any installation engaged in the production, or any intermediate process in the production, of zinc or zinc oxide from zinc sulfide ore...

40 CFR 60.171 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and in subpart A of this part. (a) Primary zinc smelter means any installation engaged in the production, or any intermediate process in the production, of zinc or zinc oxide from zinc sulfide ore... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Primary Zinc Smelters § 60.171 Definitions...

On Controlling the Hydrophobicity of Nanostructured Zinc-Oxide Layers Grown by Pulsed Electrodeposition

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

Klochko, N. P., E-mail: klochko-np@mail.ru; Klepikova, K. S.; Kopach, V. R.

The possibility of fabricating highly hydrophobic nanostructured zinc-oxide layers by the inexpensive method of pulsed electrodeposition from aqueous solutions without water-repellent coatings, adapted for large-scale production, is shown. The conditions of the deposition of highly hydrophobic nanostructured zinc-oxide layers exhibiting the “rose-petal” effect with specific morphology, optical properties, crystal structure and texture are determined. The grown ZnO nanostructures are promising for micro- and nanoelectronics as an adaptive material able to reversibly transform to the hydrophilic state upon exposure to ultraviolet radiation.

The anti-sigma factor RsrA responds to oxidative stress by reburying its hydrophobic core

PubMed Central

Rajasekar, Karthik V.; Zdanowski, Konrad; Yan, Jun; Hopper, Jonathan T. S.; Francis, Marie-Louise R.; Seepersad, Colin; Sharp, Connor; Pecqueur, Ludovic; Werner, Jörn M.; Robinson, Carol V.; Mohammed, Shabaz; Potts, Jennifer R.; Kleanthous, Colin

2016-01-01

Redox-regulated effector systems that counteract oxidative stress are essential for all forms of life. Here we uncover a new paradigm for sensing oxidative stress centred on the hydrophobic core of a sensor protein. RsrA is an archetypal zinc-binding anti-sigma factor that responds to disulfide stress in the cytoplasm of Actinobacteria. We show that RsrA utilizes its hydrophobic core to bind the sigma factor σR preventing its association with RNA polymerase, and that zinc plays a central role in maintaining this high-affinity complex. Oxidation of RsrA is limited by the rate of zinc release, which weakens the RsrA–σR complex by accelerating its dissociation. The subsequent trigger disulfide, formed between specific combinations of RsrA's three zinc-binding cysteines, precipitates structural collapse to a compact state where all σR-binding residues are sequestered back into its hydrophobic core, releasing σR to activate transcription of anti-oxidant genes. PMID:27432510

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

PubMed

Jayalakshmi, S; Platel, Kalpana

2016-05-18

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

Preservation of Intestinal Structural Integrity by Zinc Is Independent of Metallothionein in Alcohol-Intoxicated Mice

PubMed Central

Lambert, Jason C.; Zhou, Zhanxiang; Wang, Lipeng; Song, Zhenyuan; McClain, Craig J.; Kang, Y. James

2004-01-01

Intestinal-derived endotoxins are importantly involved in alcohol-induced liver injury. Disruption of intestinal barrier function and endotoxemia are common features associated with liver inflammation and injury due to acute ethanol exposure. Zinc has been shown to inhibit acute alcohol-induced liver injury. This study was designed to determine the inhibitory effect of zinc on alcohol-induced endotoxemia and whether the inhibition is mediated by metallothionein (MT) or is independent of MT. MT knockout (MT-KO) mice were administered three oral doses of zinc sulfate (2.5 mg zinc ion/kg body weight) every 12 hours before being administered a single dose of ethanol (6 g/kg body weight) by gavage. Ethanol administration caused liver injury as determined by increased serum transaminases, parenchymal fat accumulation, necrotic foci, and an elevation of tumor necrosis factor (TNF-α). Increased plasma endotoxin levels were detected in ethanol-treated animals whose small intestinal structural integrity was compromised as determined by microscopic examination. Zinc supplementation significantly inhibited acute ethanol-induced liver injury and suppressed hepatic TNF-α production in association with decreased circulating endotoxin levels and a significant protection of small intestine structure. As expected, MT levels remained undetectable in the MT-KO mice under the zinc treatment. These results thus demonstrate that zinc preservation of intestinal structural integrity is associated with suppression of endotoxemia and liver injury induced by acute exposure to ethanol and the zinc protection is independent of MT. PMID:15161632

1.55 Micrometer Sub-Micron Finger, Interdigitated MSM Photodetector Arrays with Low Dark Current

DTIC Science & Technology

2010-02-02

pf a- IGZO TFTs. IV. RF Characteristics of Room Temperature Deposited Indium Zinc Oxide Thin - Film Transistors Depletion-mode indium zinc...III. High Performance Indium Gallium Zinc Oxide Thin Film Transistors Fabricated On Polyethylene Terephthalate Substrates High-performance...amorphous (a-) InGaZnO-based thin film transistors (TFTs) were fabricated on flexible polyethylene terephthalate (PET) substrates coated with indium

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.

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

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

Evaluation of the optical characteristics of c-axis oriented zinc oxide thin films grown by sol gel spin coating technique

NASA Astrophysics Data System (ADS)

Baisakh, K.; Behera, S.; Pati, S.

2018-03-01

In this work we have systematically studied the optical characteristics of synthesized wurzite zinc oxide thin films exhibiting (002) orientation. Using sol gel spin coating technique zinc oxide thin films are grown on pre cleaned fused quartz substrates. Structural properties of the films are studied using X-ray diffraction analysis. Micro structural analysis and thickness of the grown samples are analyzed using field emission scanning electron microscopy. With an aim to investigate the optical characteristics of the grown zinc oxide thin films the transmission and reflection spectra are evaluated in the ultraviolet-visible (UV-VIS) range. Using envelope method, the refractive index, extinction coefficient, absorption coefficient, band gap energy and the thickness of the synthesized films are estimated from the recorded UV-VIS spectra. An attempt has also been made to study the influence of crystallographic orientation on the optical characteristics of the grown films.

Nanoparticles of nickel oxide: growth and organization on zinc-substituted anionic clay matrix by one-pot route at room temperature

NASA Astrophysics Data System (ADS)

Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi

2010-10-01

A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.

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.

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents by X-ray photoelectron spectroscopy and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Siriwardane, Ranjani V.; Poston, James A.

1993-05-01

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents was performed by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive spectroscopy at temperatures of 298 to 823 K. Analysis of copper oxides indicated that the satellite structure of the Cu22p region was absent in the Cu(I) state but was present in the Cu(II) state. Reduction of CuO at room temperature was observed when the ion gauge was placed close to the sample. The satellite structure was absent in all the copper oxides at 823 K in vacuum. Differentiation of the oxidation state of copper utilizing both Cu(L 3M 4,5M 4,5) X-ray-induced Auger lines and Cu2p satellite structure, indicated that the copper in zinc copper ferrite was in the + 1 oxidation state at 823 K. This + 1 state of copper was not significantly changed after exposure to H 2, CO, and H 2O. There was an increase in Cu/Zn ratio and a decrease in Fe/Zn ratio on the surface of zinc copper ferrite at 823 K compared to that at room temperature. These conditions of copper offered the best sulfidation equilibrium for the zinc copper ferrite desulfurization sorbent. Analysis of iron oxides indicated that there was some reduction of both Fe 2O 3 and FeO at 823K. The iron in zinc copper ferrite was similar to that of Fe 2O 3 at room temperature but there was some reduction of this Fe(III) state to Fe(II) at 823 K. This reduction was more enhanced in the presence of H 2 and CO. Reduction to Fe(II) may not be desirable for the lifetime of the sorbent.

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.

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Study of the presence of fluorine in the recycled fractions during carbothermal treatment of EAF dust.

PubMed

Menad, N; Ayala, J N; Garcia-Carcedo, Fernando; Ruiz-Ayúcar, E; Hernández, A

2003-01-01

Carbothermal treatment tests of electric arc furnace dusts (EAFD) using the Waelz kiln process were carried out in pilot-scale for the production of zinc oxide. The association of halides in the EAFD, and the recycled products, such as zinc oxide fumes and high-grade iron contents fractions were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. XRD reveals the presence of chlorine and fluorine in the dusts in the form of KCl, NaCl and CaF2. An ultra-pure fraction of zinc was obtained after the Double Leaching Waelz Oxide (DLWO) process was performed on the zinc oxide fumes. The halide contents were reduced to approximately 100 ppm Cl and 700 ppm F. The rest of these elements are in the form of CaF2. About 65% F is volatilised as lead and zinc fluorides, 15% is expected in the magnetic fractions and 20% in non-magnetic fractions as CaF2 and MnF2, respectively.

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

DOEpatents

Venkataramani, Venkat S.; Ayala, Raul E.

2003-09-16

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

The influence of oxidation time on the properties of oxidized zinc films

NASA Astrophysics Data System (ADS)

Rambu, A. P.

2012-09-01

The effect of oxidation time on the structural characteristics and electronic transport mechanism of zinc oxide thin films prepared by thermal oxidation, have been investigated. Zinc metallic films were deposited by thermal evaporation under vacuum, the subsequent oxidation of Zn films being carried out in open atmosphere. XRD and AFM analysis indicate that obtained films posses a polycrystalline structure, the crystallites having a preferential orientation. Structural analysis reveals that microstructure of the films (crystallite size, surface roughness, internal stress) is depending on the oxidation time of metallic films. The electrical behavior of ZnO films was investigated, during a heat treatment (two heating/cooling cycles). It was observed that after the first heating, the temperature dependences of electrical conductivity become reversible. Mott variable range hopping model was proposed to analyze the temperature dependence of the electrical conductivity, in low temperature ranges. Values of some characteristic parameters were calculated.

In vitro effects of dental cements on hard and soft tissues associated with dental implants.

PubMed

Rodriguez, Lucas C; Saba, Juliana N; Chung, Kwok-Hung; Wadhwani, Chandur; Rodrigues, Danieli C

2017-07-01

Dental cements for cement-retained restorations are often chosen based on clinician preference for the product's material properties, mixing process, delivery mechanism, or viscosity. The composition of dental cement may play a significant role in the proliferation or inhibition of different bacterial strains associated with peri-implant disease, and the effect of dental cements on host cellular proliferation may provide further insight into appropriate cement material selection. The purpose of this in vitro study was to investigate the cellular host response of bone cells (osteoblasts) and soft tissue cells (gingival fibroblasts) to dental cements. Zinc oxide (eugenol and noneugenol), zinc phosphate, and acrylic resin cements were molded into pellets and directly applied to confluent preosteoblast (cell line MC3T3 E1) or gingival fibroblast cell cultures (cell line HGF) to determine cellular viability after exposure. Controls were defined as confluent cell cultures with no cement exposure. Direct contact cell culture testing was conducted following International Organization for Standardization 10993 methods, and all experiments were performed in triplicate. To compare either the MC3T3 E1 cell line, or the HGF cell line alone, a 1-way ANOVA test with multiple comparisons was used (α=.05). To compare the MC3T3 E1 cell line results and the HGF cell line results, a 2-way ANOVA test with multiple comparisons was used (α=.05). The results of this study illustrated that while both bone and soft tissue cell lines were vulnerable to the dental cement test materials, the soft tissue cell line (human gingival fibroblasts) was more susceptible to reduced cellular viability after exposure. The HGF cell line was much more sensitive to cement exposure. Here, the acrylic resin, zinc oxide (eugenol), and zinc phosphate cements significantly reduced cellular viability after exposure with respect to HGF cells only. Within the limitation of this in vitro cellular study, the results indicated that cell response to various implant cements varied significantly, with osteoblast proliferation much less affected than gingival fibroblast cells. Furthermore, the zinc oxide noneugenol dental cement appeared to affect the cell lines significantly less than the other test cements. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Skin changes induced by a zinc oxide dressing compared with a hydrocolloid dressing in healthy individuals.

PubMed

Nielsen, Lene Feldskov; Blume, Niels; Romme, Tina; Samuelsen, Peter; Everland, Hanne; Ifversen, Peter; Karlsmark, Tonny

2005-05-01

Incidence of skin complications in ostomy patients constitutes a well-known and well-described problem. The reasons are, however, very difficult to describe because of the many factors contributing to the problem. This article describes the skin changes derived exclusively from the adhesives used in a carefully controlled, long-term study using two fundamentally different types of adhesives: a hydrocolloid adhesive and a zinc oxide adhesive. The adhesives were changed daily on the volar forearm of 11 volunteers for a 4-week period. Once a week, transepidermal water-loss (TEWL), water content of the skin, erythema and the peel force applied for removal of the adhesives were measured. On the last day of the study, a replica of the skin surface was obtained to determine changes in the skin topography, and a biopsy was taken to study changes at the cellular level. We found increased TEWL and decreased water content in skin treated with the zinc oxide adhesive, but increased water-loss and water content when the hydrocolloid adhesive was used. In addition, the area treated with zinc oxide adhesive showed significant increase of epidermal thickness, scaly appearance and parakeratosis with similarities to pathological dry skin diseases such as psoriasis and atopic dermatitis, changes that were not found when using the hydrocolloid adhesive. The skin response seems to be the result of the content of zinc oxide and the mechanical interaction of the zinc oxide adhesive. We conclude that the nature of the adhesive plays an important role in the skin response to repeated application of adhesives, as seen in peristomal skin.

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.

Inhibition of xanthine oxidase reduces oxidative stress and improves skeletal muscle function in response to electrically stimulated isometric contractions in aged mice

PubMed Central

Ryan, Michael J.; Jackson, Janna R.; Hao, Yanlei; Leonard, Stephen S.; Alway, Stephen E.

2012-01-01

Oxidative stress is a putative factor responsible for reducing function and increasing apoptotic signaling in skeletal muscle with aging. This study examined the contribution and functional significance of the xanthine oxidase enzyme as a potential source of oxidant production in aged skeletal muscle during repetitive in situ electrically stimulated isometric contractions. Xanthine oxidase activity was inhibited in young adult and aged mice via a subcutaneously placed time release (2.5 mg/day) allopurinol pellet, 7 days prior to the start of in situ electrically stimulated isometric contractions. Gastrocnemius muscles were electrically activated with 20 maximal contractions for three consecutive days. Xanthine oxidase activity was 65% greater in the gastrocnemius muscle of aged mice compared to young mice. Xanthine oxidase activity also increased after in situ electrically stimulated isometric contractions in muscles from both young (33%) and aged (28%) mice, relative to contralateral non-contracted muscles. Allopurinol attenuated the exercise-induced increase in oxidative stress, but it did not affect the elevated basal levels of oxidative stress that was associated with aging. In addition, inhibition of xanthine oxidase activity decreased caspase 3 activity, but it had no effect on other markers of mitochondrial associated apoptosis. Our results show that compared to control conditions, suppression of xanthine oxidase activity by allopurinol reduced xanthine oxidase activity, H2O2 levels, lipid peroxidation and caspase-3 activity, prevented the in situ electrically stimulated isometric contraction-induced loss of glutathione, prevented the increase of catalase and copper-zinc superoxide dismutase activities, and increased maximal isometric force in the plantar flexor muscles of aged mice after repetitive electrically evoked contractions. PMID:21530649

Surface acoustic waves/silicon monolithic sensor processor

NASA Technical Reports Server (NTRS)

Kowel, S. T.; Kornreich, P. G.; Fathimulla, M. A.; Mehter, E. A.

1981-01-01

Progress is reported in the creation of a two dimensional Fourier transformer for optical images based on the zinc oxide on silicon technology. The sputtering of zinc oxide films using a micro etch system and the possibility of a spray-on technique based on zinc chloride dissolved in alcohol solution are discussed. Refinements to techniques for making platinum silicide Schottky barrier junctions essential for constructing the ultimate convolver structure are described.

[Efficacy of using zinc oxide nanoparticles in nutrition. Experiments on the laboratory animal].

PubMed

Raspopov, R V; Trushina, E N; Mustafina, O K; Tananova, O N; Gmoshinskiĭ, I V; Khotimchenko, S A

2011-01-01

In experiments on rats there was researched bioavailability of zinc oxide (ZnO) nanoparticles. There were determined the content of Zn in blood serum and tibia, intestinal uptake of macromolecules of egg albumin, some hematological, biochemical and immune indices, liver cells apoptosis. The results obtained show that the uptake of nanoparticles of ZnO enables restoration of this microelement status damaged by zinc deficit diet.

Cordyceps sinensis oral liquid prolongs the lifespan of the fruit fly, Drosophila melanogaster, by inhibiting oxidative stress.

PubMed

Zou, Yingxin; Liu, Yuxiang; Ruan, Minghua; Feng, Xu; Wang, Jiachun; Chu, Zhiyong; Zhang, Zesheng

2015-10-01

This study investigated the effect of Cordyceps sinensis oral liquid (CSOL) on the lifespan of Drosophila melanogaster (fruit fly). Following the lifelong treatment of fruit flies with CSOL, lifespan was examined. The activity of copper-zinc-containing superoxide dismutase 1 (SOD1), manganese-containing superoxide dismutase 2 (SOD2) and catalase (CAT), as well as the lipofuscin (LF) content were determined. The mRNA levels of SOD1, SOD2 and CAT were quantified by qPCR. Hydrogen peroxide (H2O2) and paraquat were used to mimic the effects of damage caused by acute oxidative stress. D-galactose was used to mimic chronic pathological aging. CSOL significantly prolonged the lifespan of the fruit flies under physiological conditions. The activity of SOD1 and CAT was upregulated, and LF accumulation was inhibited by CSOL. CSOL had no effect on the transcriptional levels (mRNA) of these enzymes. The survival time of the fruit flies which were negatively affected by exposure to H2O2 or paraquat was significantly prolonged by CSOL. In fruit flies pathologically aged by epxosure to D-galactose, CSOL also significantly prolonged their lifespan, upregulated the activity of SOD1 and CAT, and inhibited LF accumulation. The findings of our study indicate that CSOL prolongs the lifespan of fruit flies through an anti-oxidative stress pathway involving the upregulation of SOD1 and CAT activity and the inhibition of LF accumulation. CSOL may thus be explored as a novel agent for slowing the human aging process.

Cordyceps sinensis oral liquid prolongs the lifespan of the fruit fly, Drosophila melanogaster, by inhibiting oxidative stress

PubMed Central

ZOU, YINGXIN; LIU, YUXIANG; RUAN, MINGHUA; FENG, XU; WANG, JIACHUN; CHU, ZHIYONG; ZHANG, ZESHENG

2015-01-01

This study investigated the effect of Cordyceps sinensis oral liquid (CSOL) on the lifespan of Drosophila melanogaster (fruit fly). Following the lifelong treatment of fruit flies with CSOL, lifespan was examined. The activity of copper-zinc-containing superoxide dismutase 1 (SOD1), manganese-containing superoxide dismutase 2 (SOD2) and catalase (CAT), as well as the lipofuscin (LF) content were determined. The mRNA levels of SOD1, SOD2 and CAT were quantified by qPCR. Hydrogen peroxide (H2O2) and paraquat were used to mimic the effects of damage caused by acute oxidative stress. D-galactose was used to mimic chronic pathological aging. CSOL significantly prolonged the lifespan of the fruit flies under physiological conditions. The activity of SOD1 and CAT was upregulated, and LF accumulation was inhibited by CSOL. CSOL had no effect on the transcriptional levels (mRNA) of these enzymes. The survival time of the fruit flies which were negatively affected by exposure to H2O2 or paraquat was significantly prolonged by CSOL. In fruit flies pathologically aged by epxosure to D-galactose, CSOL also significantly prolonged their lifespan, upregulated the activity of SOD1 and CAT, and inhibited LF accumulation. The findings of our study indicate that CSOL prolongs the lifespan of fruit flies through an anti-oxidative stress pathway involving the upregulation of SOD1 and CAT activity and the inhibition of LF accumulation. CSOL may thus be explored as a novel agent for slowing the human aging process. PMID:26239097

Zinc Regulation of Aminopeptidase B Involved in Neuropeptide Production

PubMed Central

Hwang, Shin-Rong; Hook, Vivian

2009-01-01

Aminopeptidase B (AP-B) is a metallopeptidase that removes basic residues from the N-termini of neuropeptide substrates in secretory vesicles. This study assessed zinc regulation of AP-B activity, since secretory vesicles contain endogenous zinc. AP-B was inhibited by zinc at concentrations typically present in secretory vesicles. Zinc effects were dependent on concentration, incubation time, and the molar ratio of zinc to enzyme. AP-B activity was recovered upon removal of zinc. AP-B with zinc became susceptible to degradation by trypsin, suggesting that zinc alters enzyme conformation. Zinc regulation demonstrates the metallopeptidase property of AP-B. PMID:18571504

Compound 13, an α1-selective small molecule activator of AMPK, inhibits Helicobacter pylori-induced oxidative stresses and gastric epithelial cell apoptosis

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

Zhao, Hangyong; Zhu, Huanghuang; Lin, Zhou

Half of the world's population experiences Helicobacter pylori (H. pylori) infection, which is a main cause of gastritis, duodenal and gastric ulcer, and gastric cancers. In the current study, we investigated the potential role of compound 13 (C13), a novel α1-selective small molecule activator of AMP-activated protein kinase (AMPK), against H. pylori-induced cytotoxicity in cultured gastric epithelial cells (GECs). We found that C13 induced significant AMPK activation, evidenced by phosphorylation of AMPKα1 and ACC (acetyl-CoA carboxylase), in both primary and transformed GECs. Treatment of C13 inhibited H. pylori-induced GEC apoptosis. AMPK activation was required for C13-mediated GEC protection. Inhibition ofmore » AMPK kinase activity by the AMPK inhibitor Compound C, or silencing AMPKα1 expression by targeted-shRNAs, alleviated C13-induced GEC protective activities against H. pylori. Significantly, C13 inhibited H. pylori-induced reactive oxygen species (ROS) production in GECs. C13 induced AMPK-dependent expression of anti-oxidant gene heme oxygenase (HO-1) in GECs. Zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP), two HO-1 inhibitors, not only suppressed C13-mediated ROS scavenging activity, but also alleviated its activity in GECs against H. pylori. Together, these results indicate that C13 inhibits H. pylori-induced ROS production and GEC apoptosis through activating AMPK–HO–1 signaling. - Highlights: • We synthesized compound 13 (C13), a α1-selective small molecule AMPK activator. • C13-induced AMPK activation requires α1 subunit in gastric epithelial cells (GECs). • C13 enhances Helicobacter pylori-induced pro-survival AMPK activation to inhibit GEC apoptosis. • C13 inhibits H. pylori-induced reactive oxygen species (ROS) production in GECs. • AMPK-heme oxygenase (HO-1) activation is required for C13-mediated anti-oxidant activity.« less

The effect of zinc injection on the increasing of Inconel 600 TT corrosion resistances

NASA Astrophysics Data System (ADS)

Febrianto; Sriyono; Widodo, Surip; Sunaryo, Geni Rina

2018-02-01

Many failures were found in reactor pressure vessel head penetration (RPV) head material. Those failures caused by boric acid corrosion, and from visual examination were found a big hole and white deposit crystal of boric acid during shutdown maintenance at David Besse reactor. Zinc Oxide addition in BWR reactor known as Zinc Injection that has purposed to reduce radiation exposure cause of Hydrogen addition. Beside reducing the radiation exposure, Zinc injection also has an effect in reducing material corrosion. The purpose of study is to determine the effect of zinc addition, boric acid, temperature also the effects of Cobalt Nitrate and Zinc Oxide addition to Inconel 600 TT as RPV head penetration material. The result in the BWR reactor experience will be implementated at PWR reactor, weather zinc oxide addition also has an effect in reducing the corrosion of Inconel 600. The method that used in this research is to observe the corrosion rates for Inconel 600 material using Potentiostat. Examination were conducted in 30, 40, 60, 70, 80 and 80 °C using 1000, 1500, 2000, 2500 and 3000 ppm boric acid concentration. The results showed that the corrosion rate for the material were very small, but the highest corrosion rate occurred in 3000 ppm boric acid concentration at 90 °C with Cobalt Nitrate addition, around 5.210 x 10-1 mpy. In the same condition at 3000 ppm boric acid concentration for temperature at 90 °C, Inconel 600 TT corrosion rate is smaller with Zinc oxide addition, around 4.631 x 10-1 mpy.

Effects of Zinc Supplementation on Endocrine Outcomes in Women with Polycystic Ovary Syndrome: a Randomized, Double-Blind, Placebo-Controlled Trial.

PubMed

Jamilian, Mehri; Foroozanfard, Fatemeh; Bahmani, Fereshteh; Talaee, Rezvan; Monavari, Mahshid; Asemi, Zatollah

2016-04-01

The current study was conducted to evaluate the effects of zinc supplementation on endocrine outcomes, biomarkers of inflammation, and oxidative stress in patients with polycystic ovary syndrome (PCOS). This study was a randomized double-blind, placebo-controlled trial. Forty-eight women (18-40 years) with PCOS diagnosed according to Rotterdam criteria were randomly assigned to receive either 220 mg zinc sulfate (containing 50 mg zinc) (group 1; n = 24) and/or placebo (group 2; n = 24) for 8 weeks. Hormonal profiles, biomarkers of inflammation, and oxidative stress were measured at study baseline and after 8-week intervention. After 8 weeks of intervention, alopecia (41.7 vs. 12.5%, P = 0.02) decreased compared with the placebo. Additionally, patients who received zinc supplements had significantly decreased hirsutism (modified Ferriman-Gallwey scores) (-1.71 ± 0.99 vs. -0.29 ± 0.95, P < 0.001) and plasma malondialdehyde (MDA) levels (-0.09 ± 1.31 vs. +2.34 ± 5.53 μmol/L, P = 0.04) compared with the placebo. A trend toward a significant effect of zinc intake on reducing high-sensitivity C-reactive protein (hs-CRP) levels (P = 0.06) was also observed. We did observe no significant changes of zinc supplementation on hormonal profiles, inflammatory cytokines, and other biomarkers of oxidative stress. In conclusion, using 50 mg/day elemental zinc for 8 weeks among PCOS women had beneficial effects on alopecia, hirsutism, and plasma MDA levels; however, it did not affect hormonal profiles, inflammatory cytokines, and other biomarkers of oxidative stress.

Regeneration of zinc chloride hydrocracking catalyst

DOEpatents

Zielke, Clyde W.

1979-01-01

Improved rate of recovery of zinc values from the solids which are carried over by the effluent vapors from the oxidative vapor phase regeneration of spent zinc chloride catalyst is achieved by treatment of the solids with both hydrogen chloride and calcium chloride to selectively and rapidly recover the zinc values as zinc chloride.

High mobility and high stability glassy metal-oxynitride materials and devices

NASA Astrophysics Data System (ADS)

Lee, Eunha; Kim, Taeho; Benayad, Anass; Hur, Jihyun; Park, Gyeong-Su; Jeon, Sanghun

2016-04-01

In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance. Here we performed post argon plasma process on zinc oxynitride film, forming nano-crystalline structure in stable amorphous matrix which hampers the reaction of oxygen with zinc. Therefore, material properties and device performance of zinc oxynitride are greatly enhanced, exhibiting robust compositional stability even exposure to air, uniform phase, high electron mobility, negligible fast transient charging and low noise characteristics. Furthermore, We expect high mobility and high stability zinc oxynitride customized by plasma process to be applicable to a broad range of semiconductor and display devices.

Zinc deficiency during growth: influence on renal function and morphology.

PubMed

Tomat, Analía Lorena; Costa, María Angeles; Girgulsky, Luciana Carolina; Veiras, Luciana; Weisstaub, Adriana Ruth; Inserra, Felipe; Balaszczuk, Ana María; Arranz, Cristina Teresa

2007-03-13

This study was designed to investigate the effects of moderate zinc deficiency during growth on renal morphology and function in adult life. Weaned male Wistar rats were divided into two groups and fed either a moderately zinc-deficient diet (zinc: 8 mg/kg, n=12) or a control diet (zinc: 30 mg/kg, n=12) for 60 days. We evaluated: renal parameters, NADPH-diaphorase and nitric oxide synthase activity in kidney, renal morphology and apoptotic cells in renal cortex. Zinc-deficient rats showed a decrease in glomerular filtration rate and no changes in sodium and potassium urinary excretion. Zinc deficiency decreased NADPH diaphorase activity in glomeruli and tubular segment of nephrons, and reduced activity of nitric oxide synthase in the renal medulla and cortex, showing that zinc plays an important role in preservation of the renal nitric oxide system. A reduction in nephron number, glomerular capillary area and number of glomerular nuclei in cortical and juxtamedullary areas was observed in zinc deficient kidneys. Sirius red staining and immunostaining for alpha-smooth muscle-actin and collagen III showed no signs of fibrosis in the renal cortex and medulla. An increase in the number of apoptotic cells in distal tubules and cortical collecting ducts neighboring glomeruli and, to a lesser extent, in the glomeruli was observed in zinc deficient rats. The major finding of our study is the emergence of moderate zinc deficiency during growth as a potential nutritional factor related to abnormalities in renal morphology and function that facilitates the development of cardiovascular and renal diseases in adult life.

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

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

Khan, Samreen Heena, E-mail: samreen.heena.khan@gmail.com; Suriyaprabha, R.; Pathak, Bhawana, E-mail: bhawana.pathak@cug.ac.in

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 manymore » 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 nanoparticle under the size range of 50nm. The XRD data showed that the ZnO-3 which was synthesized using Zinc Nitrate Hexahydrate as precursor showed the hexagonal wurtzite crystal structure. The XRD data obtained were compared with the JCPDS standard data. The precursor Zinc Nitrate Hexahydrate (ZnO-3) showed the good yield, monodispersity and size of nanoparticle under the range of 50 nm. The ZnO nanoparticles synthesize using different precursor was found effective in order of ZnO-3, followed by ZnO-1 & ZnO-2. The Synthesized ZnO has wider application in environmental remediation and clean-up as a potential nano-catalyst.« less

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.

Zinc oxide nanorods functionalized paper for protein preconcentration in biodiagnostics

NASA Astrophysics Data System (ADS)

Tiwari, Sadhana; Vinchurkar, Madhuri; Rao, V. Ramgopal; Garnier, Gil

2017-03-01

Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept.

Zinc oxide nanoparticles as selective killers of proliferating cells

PubMed Central

Taccola, Liuba; Raffa, Vittoria; Riggio, Cristina; Vittorio, Orazio; Iorio, Maria Carla; Vanacore, Renato; Pietrabissa, Andrea; Cuschieri, Alfred

2011-01-01

Background: It has recently been demonstrated that zinc oxide nanoparticles (ZnO NPs) induce death of cancerous cells whilst having no cytotoxic effect on normal cells. However, there are several issues which need to be resolved before translation of zinc oxide nanoparticles into medical use, including lack of suitable biocompatible dispersion protocols and a better understanding being needed of the mechanism of their selective cytotoxic action. Methods: Nanoparticle dose affecting cell viability was evaluated in a model of proliferating cells both experimentally and mathematically. The key issue of selective toxicity of ZnO NPs toward proliferating cells was addressed by experiments using a biological model of noncancerous cells, ie, mesenchymal stem cells before and after cell differentiation to the osteogenic lineage. Results: In this paper, we report a biocompatible protocol for preparation of stable aqueous solutions of monodispersed zinc oxide nanoparticles. We found that the threshold of intracellular ZnO NP concentration required to induce cell death in proliferating cells is 0.4 ± 0.02 mM. Finally, flow cytometry analysis revealed that the threshold dose of zinc oxide nanoparticles was lethal to proliferating pluripotent mesenchymal stem cells but exhibited negligible cytotoxic effects to osteogenically differentiated mesenchymal stem cells. Conclusion: Results confirm the ZnO NP selective cytotoxic action on rapidly proliferating cells, whether benign or malignant. PMID:21698081

Zinc oxide nanoparticles as selective killers of proliferating cells.

PubMed

Taccola, Liuba; Raffa, Vittoria; Riggio, Cristina; Vittorio, Orazio; Iorio, Maria Carla; Vanacore, Renato; Pietrabissa, Andrea; Cuschieri, Alfred

2011-01-01

It has recently been demonstrated that zinc oxide nanoparticles (ZnO NPs) induce death of cancerous cells whilst having no cytotoxic effect on normal cells. However, there are several issues which need to be resolved before translation of zinc oxide nanoparticles into medical use, including lack of suitable biocompatible dispersion protocols and a better understanding being needed of the mechanism of their selective cytotoxic action. Nanoparticle dose affecting cell viability was evaluated in a model of proliferating cells both experimentally and mathematically. The key issue of selective toxicity of ZnO NPs toward proliferating cells was addressed by experiments using a biological model of noncancerous cells, ie, mesenchymal stem cells before and after cell differentiation to the osteogenic lineage. In this paper, we report a biocompatible protocol for preparation of stable aqueous solutions of monodispersed zinc oxide nanoparticles. We found that the threshold of intracellular ZnO NP concentration required to induce cell death in proliferating cells is 0.4 ± 0.02 mM. Finally, flow cytometry analysis revealed that the threshold dose of zinc oxide nanoparticles was lethal to proliferating pluripotent mesenchymal stem cells but exhibited negligible cytotoxic effects to osteogenically differentiated mesenchymal stem cells. Results confirm the ZnO NP selective cytotoxic action on rapidly proliferating cells, whether benign or malignant.

Enhanced sun protection of nano-sized metal oxide particles over conventional metal oxide particles: an in vitro comparative study.

PubMed

Singh, P; Nanda, A

2014-06-01

A systematic and detailed study has been designed and conducted, taking into account some of the proposed benefits such as increased efficiency, transparency, unique texture, protection of active ingredient and higher consumer compliance of cosmetics containing nano-sized metal oxides. This study also presents an in vitro method to determine sun protection factor of the investigational sunscreen cream samples containing zinc oxide and titanium dioxide with a varied range of particle size. Finally, a comparative study has been conducted between metal oxide particles, conventional as well as nanoparticles. All the skin cosmetics formulated were thermally stable with a pH ranging from 7.9 to 8.2. Moreover, the fatty acid substance content and residue were found to be analogous to the standard values in each skin cosmetic. The skin cosmetics containing the titanium or zinc oxide nanoparticles were found to have improved spreadability as compared to skin cosmetics containing conventional titanium or zinc oxide particles, respectively. All skin cosmetics were found to have uniform distribution of the particles. The sunscreen creams containing zinc oxide nanoparticles and titanium dioxide nanoparticles were found to have higher in vitro sun protection factor (SPF of 3.65 for ZnO nanoparticles and 4.93 for TiO2 nanoparticles) as compared to that of sunscreen creams containing conventional zinc oxide particles (SPF = 2.90) and conventional titanium dioxide (SPF = 1.29), clearly indicating the effect of reduction in particles size, from micro to nano, on the sun protection factor. Good texture, better spreadability and enhanced in vitro SPF proved the advantageous role of nanoparticles in cosmetics. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Reactivity of metal oxide sorbents for removal of sulfur compounds from coal gases at high temperature and pressure

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

Kwon, K.C.; Crowe, E.R.; Gangwal, S.K.

1997-01-01

Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated to effectively remove hydrogen sulfide with various metal oxide sorbents at high temperatures and pressures. Metal oxide sorbents such as zinc titanate oxide, zinc ferrite oxide, copper oxide, manganese oxide and calcium oxide were found to be promising sorbents in comparison with other removal methods such as membrane separation and reactive membrane separation. The removal reaction of H{sub 2}S from coal gas mixtures with zinc titanate oxide sorbents was conducted in a batch reactor. The main objectives of this research are to formulate promising metal oxide sorbentsmore » for removal of hydrogen sulfide from coal gas mixtures, to compare reactivity of a formulated sorbent with a sorbent supplied by the Research Triangle Institute at high temperatures and pressures, and to determine effects of concentrations of moisture contained in coal gas mixtures on equilibrium absorption of H{sub 2}S into metal oxide sorbents. Promising durable metal oxide sorbents with high-sulfur-absorbing capacity were formulated by mixing active metal oxide powders with inert metal oxide powders and calcining these powder mixtures.« less

Reactor Experiments at the University of Minnesota.

DTIC Science & Technology

1987-07-15

metallurgy; zinc, zinc oxide; solar thermal,’ solar Pi% thermoelectrochemical’ water splitting, separation devices; reactors e, ? 20. AeSiRACT (Continue oe...reported. Water splitting, recovery of hydrogen 4. and sulfur from hydrogen sulfide, electrolysis of zinc oxide in vapor and liquid phases, oil...CH4-CO2 reforming process. 2. Hydrogen production from water and the production of hydrogen and sulfur (or ammonia and sulfuric acid) from H2S. 3

Zinc oxide doped graphene oxide films for gas sensing applications

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

Chetna,, E-mail: chetna2288@gmail.com; Kumar, Shani; Chaudhary, S.

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 nanosheetsmore » 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.« less

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)

Purification of camel liver catalase by zinc chelate affinity chromatography and pH gradient elution: An enzyme with interesting properties.

PubMed

Chafik, Abdelbasset; Essamadi, Abdelkhalid; Çelik, Safinur Yildirim; Mavi, Ahmet

2017-12-01

Climate change and increasing temperatures are global concerns. Camel (Camelus dromedarius) lives most of its life under high environmental stress in the desert and represent ideal model for studying desert adaptation among mammals. Catalase plays a key role in protecting cells against oxidative stress. For the first time, catalase from camel liver was purified to homogeneity by zinc chelate affinity chromatography using pH gradient elution, a better separation was obtained. A purification fold of 201.81 with 1.17% yield and a high specific activity of 1132539.37U/mg were obtained. The native enzyme had a molecular weight of 268kDa and was composed of four subunits of equal size (65kDa). The enzyme showed optimal activity at a temperature of 45°C and pH 7.2. Thiol reagents, β-Mercaptoethanol and D,L-Dithiothreitol, inhibited the enzyme activity. The enzyme was inhibited by Al 3+ , Cd 2+ and Mg 2+ , whereas Ca 2+ , Co 2+ and Ni 2+ stimulated the catalase activity. Reduced glutathione has no effect on catalase activity. The K m and V max of the enzyme for hydrogen peroxide were 37.31mM and 6185157U/mg, respectively. Sodium azide inhibited the enzyme noncompetitively with K i value of 14.43μM, the IC 50 was found to be 16.71μM. The properties of camel catalase were different comparing to those of mammalian species. Relatively higher molecular weight, higher optimum temperature, protection of reduced glutathione from hydrogen peroxide oxidation and higher affinity for hydrogen peroxide and sodium azide, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert. Copyright © 2017 Elsevier B.V. All rights reserved.

Evidence for a zinc/proton antiporter in rat brain.

PubMed

Colvin, R A; Davis, N; Nipper, R W; Carter, P A

2000-05-01

The data presented in this paper are consistent with the existence of a plasma membrane zinc/proton antiport activity in rat brain. Experiments were performed using purified plasma membrane vesicles isolated from whole rat brain. Incubating vesicles in the presence of various concentrations of 65Zn2+ resulted in a rapid accumulation of 65Zn2+. Hill plot analysis demonstrated a lack of cooperativity in zinc activation of 65Zn2+ uptake. Zinc uptake was inhibited in the presence of 1 mM Ni2+, Cd2+, or CO2+. Calcium (1 mM) was less effective at inhibiting 65Zn2+ uptake and Mg2+ and Mn2+ had no effect. The initial rate of vesicular 65Zn2+ uptake was inhibited by increasing extravesicular H+ concentration. Vesicles preloaded with 65Zn2+ could be induced to release 65Zn2+ by increasing extravesicular H+ or addition of 1 mM nonradioactive Zn2+. Hill plot analysis showed a lack of cooperativity in H+ activation of 65Zn2+ release. Based on the Hill analyses, the stoichiometry of transport may include Zn2+/Zn2+ exchange and Zn2+/H+ antiport, the latter being potentially electrogenic. Zinc/proton antiport may be an important mode of zinc uptake into neurons and contribute to the reuptake of zinc to replenish presynaptic vesicle stores after stimulation.

Characterization of zinc oxide thin film for pH detector

NASA Astrophysics Data System (ADS)

Hashim, Uda; Fathil, M. F. M.; Arshad, M. K. Md; Gopinath, Subash C. B.; Uda, M. N. A.

2017-03-01

This paper presents the fabrication process of the zinc oxide thin films for using to act as pH detection by using different PH solution. Sol-gel solution technique is used for preparing zinc oxide seed solution, followed by metal oxide deposition process by using spin coater on the silicon dioxide. Silicon dioxide layer is grown on the silicon wafer, then, ZnO seed solution is deposited on the silicon layer, baked, and annealing process carried on to undergo the characterization of its surface morphology, structural and crystalline phase. Electrical characterization is showed by using PH 4, 7, and 10 is dropped on the surface of the die, in addition, APTES solution is used as linker and also as a references of the electrical characterization.

Enhanced photocatalytic activity of nanocellulose supported zinc oxide composite for RhB dye as well as ciprofloxacin drug under sunlight/visible light

NASA Astrophysics Data System (ADS)

Tavker, Neha; Sharma, Manu

2018-05-01

Zinc oxide nanoparticles were synthesised from zinc acetate di-hydrate via co-precipitation method. Nanocellulose was isolated from agrowaste using chemo-mechanical treatments and characterized. Nanocellulose supported zinc oxide composites were prepared through in-situ method by adding different amounts of nanocellulose. The photocatalytic efficiency of pure Zno and nanocellulose supported ZnO was calculated using RhB dye under visible light and sun light. The composites which had nanocellulose in greater ratio showed higher degradation efficiency in sunlight rather than visible light for both; dye and drug. All the composites showed high rate of photodegradation compared to bare ZnO and bare nanocellulose. The enhancement in photocatalytic activity was observed maximum where the amount of cellulose was maximum. The maximum observed rate was 0.025 min-1 using Ciprofloxacin drug due to the increase in lifetime of Z4 sample delaying the electron and hole pair recombination. The degrading efficiency of nanocellulose supported zinc oxide (NC/ZnO) composite for RhB was found to be 35% in visible, 76% in sunlight and 75% for ciprofloxacin under sunlight.

CHP1002, a novel andrographolide derivative, inhibits pro-inflammatory inducible nitric oxide synthase and cyclooxygenase-2 expressions in RAW264.7 macrophages via up-regulation of heme oxygenase-1 expression.

PubMed

Zhang, Bo; Yan, Lingdi; Zhou, Peilan; Dong, Zhaoqi; Feng, Siliang; Liu, Keliang; Gong, Zehui

2013-02-01

Andrographolides, a type of diterpene lactone, are widely known to have anti-inflammatory and anti-oxidative properties. CHP1002, a synthetic derivative of andrographolide, has similar anti-inflammatory action in mouse ear swelling test and rat paw edema test. In the present study, the mechanism of anti-inflammatory effects of CHP1002 was investigated in RAW264.7 macrophages. CHP1002 potently suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. CHP1002 reduced the production of iNOS-derived nitric oxide (NO) and COX-2-derived prostaglandin E2 (PGE2). CHP1002 induced heme oxygenase-1 (HO-1) expression via activation of extracellular signal-regulated kinase (ERK) and NF-E2 related factor 2 transcription factor (Nrf2). Down-regulation of LPS-induced iNOS and COX-2 expressions was partially reversed by the HO-1 inhibitor zinc protoporphyrin (ZnPP). In addition, CHP1002 significantly attenuated LPS-induced TNF-α, IL-1β and IL-6 production. CHP1002 effectively induced HO-1 and was capable of inhibiting some macrophage-derived pro-inflammatory mediators, which may be closely correlated with its anti-inflammatory action. Copyright © 2012 Elsevier B.V. All rights reserved.

Impact of glutathione metabolism on zinc homeostasis in Saccharomyces cerevisiae.

PubMed

Steiger, Matthias G; Patzschke, Anett; Holz, Caterina; Lang, Christine; Causon, Tim; Hann, Stephan; Mattanovich, Diethard; Sauer, Michael

2017-06-01

Zinc is a crucial mineral for all organisms as it is an essential cofactor for the proper function of a plethora of proteins and depletion of zinc causes oxidative stress. Glutathione is the major redox buffering agent in the cell and therefore important for mitigation of the adverse effects of oxidative stress. In mammalian cells, zinc deficiency is accompanied by a glutathione depletion. In the yeast Saccharomyces cerevisiae, the opposite effect is observed: under low zinc conditions, an elevated glutathione concentration is found. The main regulator to overcome zinc deficiency is Zap1p. However, we show that Zap1p is not involved in this glutathione accumulation phenotype. Furthermore, we found that in glutathione-accumulating strains also the metal ion-binding phytochelatin-2, which is an oligomer of glutathione, is accumulated. This increased phytochelatin concentration correlates with a lower free zinc level in the vacuole. These results suggest that phytochelatin is important for zinc buffering in S. cerevisiae and thus explains how zinc homeostasis is connected with glutathione metabolism. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The interaction of zinc oxide-based dental cements with aqueous solutions of potassium fluoride.

PubMed

Pawluk, K; Booth, S E; Coleman, N J; Nicholson, J W

2008-09-01

The ability of zinc oxide-based dental cements (zinc phosphate and zinc polycarboxylate) to take up fluoride from aqueous solution has been studied. Only zinc phosphate cement was found to take up any measurable fluoride after 5 h exposure to the solutions. The zinc oxide filler of the zinc phosphate also failed to take up fluoride from solution. The key interaction for this uptake was thus shown to involve the phosphate groups of the set cement. However, whether this took the form of phosphate/fluoride exchange, or the formation of oxyfluoro-phosphate groups was not clear. Fluoride uptake followed radicaltime kinetics for about 2 h in some cases, but was generally better modelled by the Elovich equation, dq(t)/dt = alpha exp(-betaq(t)). Values for alpha varied from 3.80 to 2.48 x 10(4), and for beta from 7.19 x 10(-3) to 0.1946, though only beta showed any sort of trend, becoming smaller with increasing fluoride concentration. Fluoride was released from the zinc phosphate cements in processes that were diffusion based up to M(t)/M(infinity) of about 0.4. No further release occurred when specimens were placed in fresh volumes of deionised water. Only a fraction of the fluoride taken up was re-released, demonstrating that most of the fluoride taken up becomes irreversibly bound within the cement.

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

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.

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.

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.

Room-temperature synthesis of zinc oxide nanoparticles in different media and their application in cyanide photodegradation

PubMed Central

2013-01-01

Cyanide is an extreme hazard and extensively found in the wastes of refinery, coke plant, and metal plating industries. A simple, fast, cost-effective, room-temperature wet chemical route, based on cyclohexylamine, for synthesizing zinc oxide nanoparticles in aqueous and enthanolic media was established and tested for the photodegradation of cyanide ions. Particles of polyhedra morphology were obtained for zinc oxide, prepared in ethanol (ZnOE), while spherical and some chunky particles were observed for zinc oxide, prepared in water (ZnOW). The morphology was crucial in enhancing the cyanide ion photocatalytic degradation efficiency of ZnOE by a factor of 1.5 in comparison to the efficiency of ZnOW at an equivalent concentration of 0.02 wt.% ZnO. Increasing the concentration wt.% of ZnOE from 0.01 to 0.09 led to an increase in the photocatalytic degradation efficiency from 85% to almost 100% after 180 min and a doubling of the first-order rate constant (k). PMID:24314056

Zinc oxide nanocolloids prepared by picosecond pulsed laser ablation in water at different temperatures

NASA Astrophysics Data System (ADS)

D'Urso, Luisa; Spadaro, Salvatore; Bonsignore, Martina; Santangelo, Saveria; Compagnini, Giuseppe; Neri, Fortunato; Fazio, Enza

2018-01-01

Zinc oxide with wide direct band gap and high exciton binding energy is one of the most promising materials for ultraviolet (UV) light-emitting devices. It further exhibits good performance in the degradation of non-biodegradable pollutants under UV irradiation. In this work, zinc oxide (ZnO) and zinc oxide/gold (ZnO/Au) nanocolloids are prepared by picosecond pulsed laser ablation (ps-PLA), using a Zn and Au metallic targets in water media at room temperature (RT) and 80°C. ZnO and Au nanoparticles (NPs) with size in the 10-50 nm range are obtained at RT, while ZnO nanorods (NRs) are formed when water is maintained at 80°C during the ps-PLA process. Au NPs, added to ZnO colloids after the ablation process, decorate ZnO NRs. The crystalline phase of all ZnO nanocolloids is wurtzite. Methylene blue dye is used to investigate the photo-catalytic activity of all the synthesised nanocolloids, under UV light irradiation.

Highly Attrition Resistant Zinc Oxide-Based Sorbents for H2S Removal by Spray Drying Technique

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

Ryu, C.K.; Lee, J.B.; Ahn, D.H.

2002-09-19

Primary issues for the fluidized-bed/transport reactor process are high attrition resistant sorbent, its high sorption capacity and regenerability, durability, and cost. The overall objective of this project is the development of a superior attrition resistant zinc oxide-based sorbent for hot gas cleanup in integrated coal gasification combined cycle (IGCC). Sorbents applicable to a fluidized-bed hot gas desulfurization process must have a high attrition resistance to withstand the fast solid circulation between a desulfurizer and a regenerator, fast kinetic reactions, and high sulfur sorption capacity. The oxidative regeneration of zinc-based sorbent usually initiated at greater than 600 C with highly exothermicmore » nature causing deactivation of sorbent as well as complication of sulfidation process by side reaction. Focusing on solving the sorbent attrition and regenerability of zinc oxide-based sorbent, we have adapted multi-binder matrices and direct incorporation of regeneration promoter. The sorbent forming was done with a spray drying technique that is easily scalable to commercial quantity.« less

Plasmon resonance and perfect light absorption in subwavelength trench arrays etched in gallium-doped zinc oxide film

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

Hendrickson, Joshua R., E-mail: joshua.hendrickson.4@us.af.mil; Leedy, Kevin; Cleary, Justin W.

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 fabricationmore » 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.« less

Gaseous species as reaction tracers in the solvothermal synthesis of the zinc oxide terephthalate MOF-5.

PubMed

Hausdorf, Steffen; Baitalow, Felix; Seidel, Jürgen; Mertens, Florian O R L

2007-05-24

Gaseous species emitted during the zinc oxide/zinc hydroxide 1,4-benzenedicarboxylate metal organic framework synthesis (MOF-5, MOF-69c) have been used to investigate the reaction scheme that leads to the framework creation. Changes of the gas-phase composition over time indicate that the decomposition of the solvent diethylformamide occurs at least via two competing reaction pathways that can be linked to the reaction's overall water and pH management. From isotope exchange experiments, we deduce that one of the decomposition pathways leads to the removal of water from the reaction mixture, which sets the conditions when the synthesis of an oxide-based (MOF-5) instead of an hydroxide-based MOF (MOF-69c) occurs. A quantitative account of most reactants and byproducts before and after the MOF-5/MOF-69c synthesis is presented. From the investigation of the reaction intermediates and byproducts, we derive a proposal of a basic reaction scheme for the standard synthesis zinc oxide carboxylate MOFs.

Antibacterial effects, biocompatibility and electrochemical behavior of zinc incorporated niobium oxide coating on 316L SS for biomedical applications

NASA Astrophysics Data System (ADS)

Pradeep PremKumar, K.; Duraipandy, N.; Manikantan Syamala, Kiran; Rajendran, N.

2018-01-01

In the present study, Nb2O5 (NZ0) composite coatings with various concentrations of zinc (NZ2, NZ4 & NZ6) are produced on 316L SS by sol-gel method with the aim of improving its antibacterial activity, bone formability and corrosion resistance properties. This work studied the surface characterization of NZ0, NZ2, NZ4 & NZ6 coated 316L SS by ATR-FTIR, XRD, HR-SEM with EDAX. The synthesized coatings were different in the morphological aspects, NZ0 shows mesoporous morphology whereas irregular cluster like morphology was observed for the zinc incorporated coatings. The chemical composition of the NZ0 and NZ4 composite coatings were studied by XPS and the results revealed that the zinc exist as ZnO and Nb as Nb2O5 in the coatings. The increase in the concentration of zinc in Nb2O5 increases the hydrophilic nature identified by water contact angle studies. The potentiodynamic polarization studies in simulated body fluid reveals the increase in polarization resistance with decrease in current density (icorr) and electrochemical impedance spectroscopic studies with increase in charge transfer resistance (Rct) and double layer capacitance (Qdl) were observed for NZ4 coated 316L SS. The inhibition of Staphylococcus aureus and Escherichia coli bacteria were identified for NZ4 coated 316L SS by bacterial viability studies. The NZ4 coated 316L SS showed better Osseo-integration by spreading the MG 63 osteoblast cells. The study results imply that zinc incorporated Nb2O5 (NZ4) composite coating exhibits antibacterial activity and also enhance the corrosion resistance and biocompatibility of the 316L SS.

The effect of Mg dopants on magnetic and structural properties of iron oxide and zinc ferrite thin films

NASA Astrophysics Data System (ADS)

Saritaş, Sevda; Ceviz Sakar, Betul; Kundakci, Mutlu; Yildirim, Muhammet

2018-06-01

Iron oxide thin films have been obtained significant interest as a material that put forwards applications in photovoltaics, gas sensors, biosensors, optoelectronic and especially in spintronics. Iron oxide is one of the considerable interest due to its chemical and thermal stability. Metallic ion dopant influenced superexchange interactions and thus changed the structural, electrical and magnetic properties of the thin film. Mg dopped zinc ferrite (Mg:ZnxFe3-xO4) crystal was used to avoid the damage of Fe3O4 (magnetite) crystal instead of Zn2+ in this study. Because the radius of the Mg2+ ion in the A-site (tetrahedral) is almost equal to that of the replaced Fe3+ ion. Inverse-spinel structure in which oxygen ions (O2-) are arranged to form a face-centered cubic (FCC) lattice where there are two kinds of sublattices, namely, A-site and B-site (octahedral) interstitial sites and in which the super exchange interactions occur. In this study, to increase the saturation of magnetization (Ms) value for iron oxide, inverse-spinal ferrite materials have been prepared, in which the iron oxide was doped by multifarious divalent metallic elements including Zn and Mg. Triple and quaternary; iron oxide and zinc ferrite thin films with Mg metal dopants were grown by using Spray Pyrolysis (SP) technique. The structural, electrical and magnetic properties of Mg dopped iron oxide (Fe2O3) and zinc ferrite (ZnxFe3-xO4) thin films have been investigated. Vibrating Sample Magnetometer (VSM) technique was used to study for the magnetic properties. As a result, we can say that Mg dopped iron oxide thin film has huge diamagnetic and of Mg dopped zinc ferrite thin film has paramagnetic property at bigger magnetic field.

Zinc transport by respiratory epithelial cells and interaction with iron homeostasis.

PubMed

Deng, Zhongping; Dailey, Lisa A; Soukup, Joleen; Stonehuerner, Jacqueline; Richards, Judy D; Callaghan, Kimberly D; Yang, Funmei; Ghio, Andrew J

2009-10-01

Despite recurrent exposure to zinc through inhalation of ambient air pollution particles, relatively little information is known about the homeostasis of this metal in respiratory epithelial cells. We describe zinc uptake and release by respiratory epithelial cells and test the postulate that Zn(2+) transport interacts with iron homeostasis in these same cells. Zn(2+) uptake after 4 and 8 h of exposure to zinc sulfate was concentration- and time-dependent. A majority of Zn(2+) release occurred in the 4 h immediately following cell exposure to ZnSO(4). Regarding metal importers, mRNA for Zip1 and Zip2 showed no change after respiratory epithelial cell exposure to zinc while mRNA for divalent metal transporter (DMT)1 increased. Western blot assay for DMT1 protein supported an elevated expression of this transport protein following zinc exposure. RT-PCR confirmed mRNA for the metal exporters ZnT1 and ZnT4 with the former increasing after ZnSO(4). Cell concentrations of ferritin increased with zinc exposure while oxidative stress, measured as lipid peroxides, was decreased supporting an anti-oxidant function for Zn(2+). Increased DMT1 expression, following pre-incubations of respiratory epithelial cells with TNF-alpha, IFN-gamma, and endotoxin, was associated with significantly decreased intracellular zinc transport. Finally, incubations of respiratory epithelial cells with both zinc sulfate and ferric ammonium citrate resulted in elevated intracellular concentrations of both metals. We conclude that exposure to zinc increases iron uptake by respiratory epithelial cells. Elevations in cell iron can possibly affect an increased expression of DMT1 and ferritin which function to diminish oxidative stress. Comparable to other metal exposures, changes in iron homeostasis may contribute to the biological effects of zinc in specific cells and tissues.

Decolorization of brilliant green dye using immersed lamp sonophotocatalytic reactor

NASA Astrophysics Data System (ADS)

Gole, Vitthal L.; Priya, Astha; Danao, Sanjay P.

2017-12-01

The textile and dye industries require an enormous amount of water for processing and produce a large volume of wastewater. Generated wastewater had potential hazards and a threat to the aquatic biota. The present work investigates the decolorization of brilliant green dye using a combination of two advanced oxidation techniques viz sonocatalysis and photocatalysis (immersed lamp) known as sonophotocatalysis (3 L capacity). The efficiency of decolorization is further improved in the presence of various additives viz. copper oxide, zinc oxide, and sodium chloride. The maximum decolorization of brilliant green (BG) (94.8% in 120 min) obtained in the presence of zinc oxide. The total organic carbon of the treated samples was measured to monitor complete mineralization of BG. The sonophotocatalytic process (in the presence of zinc oxide) shows maximum mineralization. Synergic combination of two oxidation processes increased the production of oxidizing radicals. Continuous cleaning of catalyst surface (due to sonolysis effect) improves the activity of the catalyst for photolysis operation. The present work is highly useful for the development of a sonophotocatalytic process.

Thermodynamic Analysis of Oxygen-Enriched Direct Smelting of Jamesonite Concentrate

NASA Astrophysics Data System (ADS)

Zhang, Zhong-Tang; Dai, Xi; Zhang, Wen-Hai

2017-12-01

Thermodynamic analysis of oxygen-enriched direct smelting of jamesonite concentrate is reported in this article. First, the occurrence state of lead, antimony and other metallic elements in the smelting process was investigated theoretically. Then, the verification test was carried out. The results indicate that lead and antimony mainly exist in the alloy in the form of metallic lead and metallic antimony. Simultaneously, lead and antimony were also oxidized into the slag in the form of lead-antimony oxide. Iron and copper could be oxidized into the slag in the form of oxides in addition to combining with antimony in the alloy, while zinc was mainly oxidized into the slag in the form of zinc oxide. The verification test indicates that the main phases in the alloy contain metallic lead, metallic antimony and a small amount of Cu2Sb, FeSb2 intermetallic compounds, and the slag is mainly composed of kirschsteinite, fayalite and zinc oxide, in agreement with the thermodynamic analysis.

Antibacterial studies of ZnO nanoparticle coatings on nanocrystalline YSZ irradiated with femtosecond laser light

NASA Astrophysics Data System (ADS)

Alvarez, Crysthal; Garcia, Valeria; Cuando, Natanael; Aguilar, Guillermo

2018-02-01

Recently, efforts have been made to create a transparent ceramic cranial implant comprised of nanocrystalline yttriastabilized zirconia (nc-YSZ) that will provide optical access to the brain. This has been referred to as Window to the Brain (WttB) in the literature. WttB will allow the use of laser and photonic treatments and diagnostics in areas with difficult optical access in the brain. Nevertheless, infection is still one of the frequent cranial implant complications. In most cases a second surgery is required to replace the infected implant. To address potential infections in the WttB platform, we have studied the antibacterial effect of a Zinc Oxide (ZnO) nanoparticles coating on nc-YSZ. After coating with ZnO nanoparticles, the implant was irradiated with infrared femtosecond laser light. We synthesized ZnO nanoparticles through the Laser Ablation of Solids in Liquids (LASL) method, using a Zinc solid target in a liquid medium (water/acetone). Antibacterial coatings were obtained by air brush, using a precursor solution of ZnO nanoparticles in distilled water. Escherichia coli (E. coli) have been used as representative, clinical relevant bacteria to probe the antibacterial effect of the coating. Our previous studies suggested that the use of ZnO nanoparticles inhibit bacterial growth. Laser irradiation treatment alone also offers inhibition of bacterial growth, up to 70%. The incorporation of nanoparticles offers an additional 20% inhibition. Thus, this work represents the next step towards the development of a clinically-oriented transparent cranial implant.

A Photoluminescence Study of the Changes Induced in the Zinc White Pigment by Formation of Zinc Complexes

PubMed Central

Artesani, Alessia; Gherardi, Francesca; Nevin, Austin; Valentini, Gianluca; Comelli, Daniela

2017-01-01

It is known that oil paintings containing zinc white are subject to rapid degradation. This is caused by the interaction between the active groups of binder and the metal ions of the pigment, which gives rise to the formation of new zinc complexes (metal soaps). Ongoing studies on zinc white paints have been limited to the chemical mechanisms that lead to the formation of zinc complexes. On the contrary, little is known of the photo-physical changes induced in the zinc oxide crystal structure following this interaction. Time-resolved photoluminescence spectroscopy has been applied to follow modifications in the luminescent zinc white pigment when mixed with binder. Significant changes in trap state photoluminescence emissions have been detected: the enhancement of a blue emission combined with a change of the decay kinetic of the well-known green emission. Complementary data from molecular analysis of paints using Fourier transform infrared spectroscopy confirms the formation of zinc carboxylates and corroborates the mechanism for zinc complexes formation. We support the hypothesis that zinc ions migrate into binder creating novel vacancies, affecting the photoluminescence intensity and lifetime properties of zinc oxide. Here, we further demonstrate the advantages of a time-resolved photoluminescence approach for studying defects in semiconductor pigments. PMID:28772700

Chrysanthemum flower-like NiCo2O4-nitrogen doped graphene oxide composite: an efficient electrocatalyst for lithium-oxygen and zinc-air batteries.

PubMed

Moni, Prabu; Hyun, Suyeon; Vignesh, Ahilan; Shanmugam, Sangaraju

2017-07-06

Chrysanthemum flower-like NiCo 2 O 4 -nitrogen doped graphene oxide composite material has been explored as a bifunctional cathode electrocatalyst for aqueous zinc-air and non-aqueous lithium-oxygen batteries. This cathode exhibits maximum discharge capacities of 712 and 15 046 mA h g -1 for zinc-air and lithium-oxygen batteries, respectively, with stable cycling over 50 cycles.

Influence of ultrasound power and frequency upon corrosion kinetics of zinc in saline media.

PubMed

Doche, M-L; Hihn, J-Y; Mandroyan, A; Viennet, R; Touyeras, F

2003-10-01

This paper is devoted to zinc corrosion and oxidation mechanism in an ultrasonically stirred aerated sodium sulfate electrolyte. It follows a previous study devoted to the influence of 20 kHz ultrasound upon zinc corrosion in NaOH electrolytes [Ultrason. Sonochemis. 8 (2001) 291]. In the present work, various ultrasound regimes were applied by changing the transmitted power and the wave frequency (20 and 40 kHz). Unlike NaOH electrolyte which turns the zinc electrode into a passive state, Na2SO4 saline media induces soft corrosion conditions. This allows a study of the combined effects of ultrasonically modified hydrodynamic and mechanical damage (cavitation) upon the zinc corrosion process. A series of initial experiments were carried out so as to determine the transmitted power and to characterize mass transfer distribution in the electrochemical cell. Zinc corrosion and oxidation process were subsequently studied with respect to the vibrating parameters. When exposed to a 20 kHz ultrasonic field, and provided that the electrode is situated at a maximum mass transfer point, the corrosion rate reaches values six to eight times greater than in silent conditions. The zinc oxidation reaction, in the absence of competitive reduction reactions, is also activated by ultrasound (20 and 40 kHz) but probably through a different process of surface activation.

A new approach to synthesize ZnO tetrapod-like nanoparticles with DC thermal plasma technique

NASA Astrophysics Data System (ADS)

Lin, Hsiu-Fen; Liao, Shih-Chieh; Hu, Chen-Ti

2009-02-01

The feasibility of fabricating the tetrapod-like zinc oxide (TZ) nanoparticles with a DC thermal plasma reactor was demonstrated in the present study. Advantages of this process include the low cost and high yield rate (0.8-1.0 kg/h) in producing high TZ content mixtures (with small portion of rod-like zinc oxide (RZ) and plate-like zinc oxide (PZ) nanoparticles) from commercial metal zinc powders. ZnO nanopowders with high TZ content could be employed as the starting material for photocatalytic filters. The ratio of TZ to RZ and PZ in the products was observed to be strongly influenced by the plasma power and the plasma gas flow rate. The optical spectrum, photostability and anti-microbial property of the as-grown and annealed TZ mixtures were examined and compared in this study.

Surface acoustic wave/silicon monolithic sensor/processor

NASA Technical Reports Server (NTRS)

Kowel, S. T.; Kornreich, P. G.; Nouhi, A.; Kilmer, R.; Fathimulla, M. A.; Mehter, E.

1983-01-01

A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed.

Structural and electrical properties of sputter deposited ZnO thin films

NASA Astrophysics Data System (ADS)

Muhammed Shameem P., V.; Mekala, Laxman; Kumar, M. Senthil

2018-05-01

The growth of zinc oxide thin films having different oxygen content was achieved at ambient temperature by reactive dc magnetron sputtering technique and their structural and electrical properties are studied. The structural studies show that the films are polycrystalline with a preferential orientation of the grains along the c-axis [002], which increases with increase in oxygen partial pressure. The grain size and the surface roughness of the zinc oxide films are found to decrease with increasing oxygen partial pressure. It is observed that the resistivity of the zinc oxide films can be tuned from semiconducting to insulating regime by varying the oxygen content.

Computational predictions of zinc oxide hollow structures

NASA Astrophysics Data System (ADS)

Tuoc, Vu Ngoc; Huan, Tran Doan; Thao, Nguyen Thi

2018-03-01

Nanoporous materials are emerging as potential candidates for a wide range of technological applications in environment, electronic, and optoelectronics, to name just a few. Within this active research area, experimental works are predominant while theoretical/computational prediction and study of these materials face some intrinsic challenges, one of them is how to predict porous structures. We propose a computationally and technically feasible approach for predicting zinc oxide structures with hollows at the nano scale. The designed zinc oxide hollow structures are studied with computations using the density functional tight binding and conventional density functional theory methods, revealing a variety of promising mechanical and electronic properties, which can potentially find future realistic applications.

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.

Zinc halogen battery electrolyte composition with lead additive

DOEpatents

Henriksen, Gary L.

1981-01-01

This disclosure relates to a zinc halogen battery electrolyte composition containing an additive providing improved zinc-on-zinc recyclability. The improved electrolyte composition involves the use of a lead additive to inhibit undesirable irregular plating and reduce nodular or dendritic growth on the electrode surface. The lead-containing electrolyte composition of the present invention appears to influence not only the morphology of the base plate zinc, but also the morphology of the zinc-on-zinc replate. In addition, such lead-containing electrolyte compositions appear to reduce hydrogen formation.

Inflammatory stimuli induce inhibitory S-nitrosylation of the deacetylase SIRT1 to increase acetylation and activation of p53 and p65

PubMed Central

Shinozaki, Shohei; Chang, Kyungho; Sakai, Michihiro; Shimizu, Nobuyuki; Yamada, Marina; Tanaka, Tomokazu; Nakazawa, Harumasa; Ichinose, Fumito; Yamada, Yoshitsugu; Ishigami, Akihito; Ito, Hideki; Ouchi, Yasuyoshi; Starr, Marlene E.; Saito, Hiroshi; Shimokado, Kentaro; Stamler, Jonathan S.; Kaneki, Masao

2015-01-01

Inflammation increases the abundance of inducible nitric oxide synthase (iNOS), leading to enhanced production of nitric oxide (NO), which can modify proteins by S-nitrosylation. Enhanced NO production increases the activities of the transcription factors p53 and nuclear factor κB (NF-κB) in several models of disease-associated inflammation. S-Nitrosylation inhibits the activity of the protein deacetylase SIRT1. SIRT1 limits apoptosis and inflammation by deacetylating p53 and p65 (also known as RelA), a subunit of NF-κB. We showed in multiple cultured mammalian cell lines that NO donors or inflammatory stimuli induced S-nitrosylation of SIRT1 within CXXC motifs, which inhibited SIRT1 by disrupting its ability to bind zinc. Inhibition of SIRT1 reduced deacetylation and promoted activation of p53 and p65, leading to apoptosis and increased expression of proinflammatory genes. In rodent models of systemic inflammation, Parkinson’s disease, or aging-related muscular atrophy, S-nitrosylation of SIRT1 correlated with increased acetylation of p53 and p65 and activation of p53 and NF-κB target genes, suggesting that S-nitrosylation of SIRT1 may represent a proinflammatory switch common to many diseases and aging. PMID:25389371

Hyperaccumulation of zinc by zinc-depleted Candida utilis grown in chemostat culture.

PubMed

Lawford, H G; Pik, J R; Lawford, G R; Williams, T; Kligerman, A

1980-01-01

The steady-state levels of zinc in Candida utilis yeast grown in continuous culture under conditions of zinc limitations are <1nmol Zn2+/mg dry weight of cells. Unlike carbon-limited cells, zinc-depleted cells from a zinc-limited chemostat possess the capacity to accumulate and store zinc at levels far in excess of the steady-state level of 4 nmol/mg dry biomass observed in carbon-limited chemostat cultures. Zinc uptake is energy-dependent and apparently undirectional since accumulated 65Zn neither exists from preloaded cells nor exchanges with cold Zn2+. The transport system exhibits a high affinity for Zn2+ (Km =.36micrM) with a Vmaxof 2.2 nmol per minute per milligram dry weight of cells. Growth during the period of the uptake assay is responsible for the apparent plateau level of 35 nmol Zn2+/mg dry weight of cells achieved after 20-30 min in the presence of 65Zn at pH 4.5 and 30 degrees C. Inhibition of growth during the uptake assay by cycloheximide results in a biphasic linear pattern of zinc accumulation where the cellular zinc is about 60 nmol/mg dry weight after 1 h. The enhanced level of accumulated zinc is not inhibtory to growth. Zinc-depleted C. utilis contains elevated amounts of polyphosphate and this anionic evidence does not allow discrimination between possible regulation of zinc homestasis either by inhibitions of zinc efflux through control of the membrane carrier or by control of the synthesis of a cytoplasmic zinc-sequestering macromolecule.

Influence of solvents on the changes in structure, purity, and in vitro characteristics of green-synthesized ZnO nanoparticles from Costus igneus

NASA Astrophysics Data System (ADS)

Nandhini, G.; Suriyaprabha, R.; Maria Sheela Pauline, W.; Rajendran, V.; Aicher, Wilhelm Karl; Awitor, Oscar Komla

2018-05-01

The present study is intended to produce high-purity zinc oxide nanoparticles from the leaves of Costus igneus and zinc acetate precursor via sustainable methods by the tribulation with three different solvents (hot water, methanol, and acetone) for the extraction of plant compounds. While examining the physico-chemical characteristics of ZnO nanoparticles incurred by the catalysis of plant bioactive compounds extracted from different solvents, the hot water extract-based green synthesis process yields higher purity (99.89%) and smaller particle size (94 nm) than other solvents. The optimization of the solvents used for the green synthesis of nanoparticles renders key identification in appropriate extraction of bioactive compounds suitable for the nucleation/production of nanoparticles in addition to annealing temperature. The impregnable usage of ZnO nanoparticles in clinical applications is further confirmed based on the treatment of particles (1-10 mg ml-1) against Gram-positive (S. aureus and S. epidermis) and Gram-negative bacteria (E. coli and K. pneumoniae) with respect to their growth inhibition. An in-force growth inhibition against particular S. aureus and S. epidermis imparted by the low concentration of ZnO nanoparticles signifies the utilization and consumption of green-synthesized high-purity nanoparticles for therapeutic and cosmetic applications.

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, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

Zinc oxide hierarchical nanostructures for photocatalysis

NASA Astrophysics Data System (ADS)

Yukhnovets, O.; Semenova, A. A.; Levkevich, E. A.; Maximov, A. I.; Moshnikov, V. A.

2018-03-01

In this work, we perform the study of zinc oxide hierarchical structures synthesized by the low-temperature hydrothermal method. The paper considers morphological properties of obtained structures. Photocatalytic activity of samples was analysed by methyl orange degradation under UV irradiation. The sufficient decrease in methyl orange has been demonstrated.

Temporary protection of metals against atmospheric corrosion by saturated straight chain aliphatic monocarboxylates. Mechanisms of inhibition

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

Kapin, C.; Steinmetz, P.; Steinmetz, J.

1998-12-31

This work was devoted to the investigations of the ability of saturated straight chain aliphatic monocarboxylates to inhibit corrosion of mild steel and zinc in aerated aqueous solutions. Performances of inhibitors were shown to be dependent on their chain length, their concentration and the immersion duration. Both crystallographic parameters and solubilities of iron and zinc carboxylates were determined. Then potential-pH diagrams of iron and zinc in water were built taking the presence of metallic soaps into account. According to these diagrams, the passivation of metals was attributed to the growth of films containing metallic soaps. This model confirms that previouslymore » proposed for inhibition of copper and magnesium by the same carboxylates.« less

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.

Thermodynamic analysis of the selective chlorination of electric arc furnace dust.

PubMed

Pickles, C A

2009-07-30

The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

An Atomistic View of the Incipient Growth of Zinc Oxide Nanolayers

DOE PAGES

Chu, Manh Hung; Tian, Liang; Chaker, Ahmad; ...

2016-08-09

The growth of zinc oxide thin films by atomic layer deposition is believed to proceed through an embryonic step in which three-dimensional nanoislands form and then coalesce to trigger a layer-by-layer growth mode. This transient initial state is characterized by a poorly ordered atomic structure, which may be inaccessible by X-ray diffraction techniques. Here in this work, we apply X-ray absorption spectroscopy in situ to address the local structure of Zn after each atomic layer deposition cycle, using a custom-built reactor mounted at a synchrotron beamline, and we shed light on the atomistic mechanisms taking place during the first stagesmore » of the growth. We find that such mechanisms are surprisingly different for zinc oxide growth on amorphous (silica) and crystalline (sapphire) substrate. Ab initio simulations and quantitative data analysis allow the formulation of a comprehensive growth model, based on the different effects of surface atoms and grain boundaries in the nanoscale islands, and the consequent induced local disorder. From a comparison of these spectroscopy results with those from X-ray diffraction reported recently, we observe that the final structure of the zinc oxide nanolayers depends strongly on the mechanisms taking place during the initial stages of growth. Finally, the approach followed here for the case of zinc oxide will be of general interest for characterizing and optimizing the growth and properties of more complex nanostructures.« less

An Atomistic View of the Incipient Growth of Zinc Oxide Nanolayers

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

Chu, Manh Hung; Tian, Liang; Chaker, Ahmad

The growth of zinc oxide thin films by atomic layer deposition is believed to proceed through an embryonic step in which three-dimensional nanoislands form and then coalesce to trigger a layer-by-layer growth mode. This transient initial state is characterized by a poorly ordered atomic structure, which may be inaccessible by X-ray diffraction techniques. Here in this work, we apply X-ray absorption spectroscopy in situ to address the local structure of Zn after each atomic layer deposition cycle, using a custom-built reactor mounted at a synchrotron beamline, and we shed light on the atomistic mechanisms taking place during the first stagesmore » of the growth. We find that such mechanisms are surprisingly different for zinc oxide growth on amorphous (silica) and crystalline (sapphire) substrate. Ab initio simulations and quantitative data analysis allow the formulation of a comprehensive growth model, based on the different effects of surface atoms and grain boundaries in the nanoscale islands, and the consequent induced local disorder. From a comparison of these spectroscopy results with those from X-ray diffraction reported recently, we observe that the final structure of the zinc oxide nanolayers depends strongly on the mechanisms taking place during the initial stages of growth. Finally, the approach followed here for the case of zinc oxide will be of general interest for characterizing and optimizing the growth and properties of more complex nanostructures.« less

Loss of ErbB2-PI3K/Akt signaling prevents zinc pyrithione-induced cardioprotection during ischemia/reperfusion.

PubMed

Thokala, Sandhya; Inapurapu, Santhipriya; Bodiga, Vijaya Lakshmi; Vemuri, Praveen Kumar; Bodiga, Sreedhar

2017-04-01

The purpose of this study was to determine if zinc homeostasis is affected during ischemia/reperfusion, if so, whether zinc pyrithione limits myocardial cell death and improves hemodynamics when administered as an adjunct to reperfusion and if ErbB receptor tyrosine kinases that are important for the long-term structural integrity of the heart are indispensable for reperfusion salvage. Isolated perfused rat hearts were subjected to 35min of global ischemia and reperfused for 120min to determine the relative intracellular zinc levels by TSQ staining. The hearts were reperfused in the presence of incremental concentrations of zinc pyrithione for the first 10min during reperfusion. Silencing or blockade of ErbB2 using a monoclonal antibody, ErbB2 kinase inhibition and PI3kinase inhibition was used to study their critical role in zinc pyrithione-induced cardioprotection. We found that there was a profound decrease in intracellular zinc after ischemia/reperfusion resulting in increased apoptosis, caspase-3 activation, and infarct size. A dose-dependent reduction of infarct size with zinc pyrithione in the range of 5-20μmol/l (optimal protection was seen at 10μmol/l with infarct size of 16±2% vs. I/R vehicle, 33±2%, p<0.01). Increased TUNEL staining and caspase-3 activity observed after ischemia/reperfusion were attenuated by zinc pyrithione administration during the reperfusion. Moreover, this protection was sensitive to silencing and blockade of ErbB2, inhibition of ErbB2 kinase activity or PI3-kinase activity. Western blot analysis revealed that zinc pyrithione resulted in decreased caspase-3 activation, rapid stabilization of ErbB2/ErbB1 heterodimers, and increased activation of PI3K/Akt signaling cascade. Zinc pyrithione attenuates lethal perfusion-induced injury in a manner that is reliant on ErbB2/PI3K/Akt activity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Primary battery design and safety guidelines handbook

NASA Technical Reports Server (NTRS)

Bragg, Bobby J.; Casey, John E.; Trout, J. Barry

1994-01-01

This handbook provides engineers and safety personnel with guidelines for the safe design or selection and use of primary batteries in spaceflight programs. Types of primary batteries described are silver oxide zinc alkaline, carbon-zinc, zinc-air alkaline, manganese dioxide-zionc alkaline, mercuric oxide-zinc alkaline, and lithium anode cells. Along with typical applications, the discussions of the individual battery types include electrochemistry, construction, capacities and configurations, and appropriate safety measures. A chapter on general battery safety covers hazard sources and controls applicable to all battery types. Guidelines are given for qualification and acceptance testing that should precede space applications. Permissible failure levels for NASA applications are discussed.

Suppressive effect of zinc ion on iNOS expression induced by interferon-gamma or tumor necrosis factor-alpha in murine keratinocytes.

PubMed

Yamaoka, J; Kume, T; Akaike, A; Miyachi, Y

2000-05-01

Zinc, an essential metal, is a critical component of zinc binding proteins such as zinc fingers, zinc enzymes and metallothioneins. Recently, evidence for its anti-inflammatory property in skin has been accumulating, as shown in the treatment of acne, alopecia and zinc deficiency. In cutaneous inflammations, a large amount of nitric oxide (NO) is produced through induction of inducible nitric oxide synthase (iNOS) under the influence of proinflammatory cytokines, resulting in tissue damages in skin, as clarified in other organs. Therefore, we asked if the effect of zinc on NO production and/or on iNOS expression in keratinocytes may explain the anti-inflammatory property of zinc in skin. Accordingly, we sought to determine in this study whether zinc ion may have effect on IFN-gamma or TNF-alpha induced NO production and iNOS expression in cultured murine keratinocytes. Ten microM of zinc ion remarkably suppressed cytokine-induced NO production in keratinocytes. Furthermore, zinc ion also suppressed cytokine-induced iNOS expression in the protein level as well as in the messenger RNA level. These results suggest the possibility that the suppressive effect of zinc ion on cytokine-induced NO production in keratinocytes may be in part implicated in the anti-inflammatory property of zinc in some of skin disorders.

Analysis of amorphous indium-gallium-zinc-oxide thin-film transistor contact metal using Pilling-Bedworth theory and a variable capacitance diode model

NASA Astrophysics Data System (ADS)

Kiani, Ahmed; Hasko, David G.; Milne, William I.; Flewitt, Andrew J.

2013-04-01

It is widely reported that threshold voltage and on-state current of amorphous indium-gallium-zinc-oxide bottom-gate thin-film transistors are strongly influenced by the choice of source/drain contact metal. Electrical characterisation of thin-film transistors indicates that the electrical properties depend on the type and thickness of the metal(s) used. Electron transport mechanisms and possibilities for control of the defect state density are discussed. Pilling-Bedworth theory for metal oxidation explains the interaction between contact metal and amorphous indium-gallium-zinc-oxide, which leads to significant trap formation. Charge trapping within these states leads to variable capacitance diode-like behavior and is shown to explain the thin-film transistor operation.

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.

Sol-gel zinc oxide humidity sensors integrated with a ring oscillator circuit on-a-chip.

PubMed

Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

2014-10-28

The study develops an integrated humidity microsensor fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated humidity sensor consists of a humidity sensor and a ring oscillator circuit on-a-chip. The humidity sensor is composed of a sensitive film and branch interdigitated electrodes. The sensitive film is zinc oxide prepared by sol-gel method. After completion of the CMOS process, the sensor requires a post-process to remove the sacrificial oxide layer and to coat the zinc oxide film on the interdigitated electrodes. The capacitance of the sensor changes when the sensitive film adsorbs water vapor. The circuit is used to convert the capacitance of the humidity sensor into the oscillation frequency output. Experimental results show that the output frequency of the sensor changes from 84.3 to 73.4 MHz at 30 °C as the humidity increases 40 to 90%RH.

Structural morphology of zinc oxide structures with antibacterial application of calamine lotion

NASA Astrophysics Data System (ADS)

Ann, Ling Chuo; Mahmud, Shahrom; Bakhori, Siti Khadijah Mohd; Sirelkhatim, Amna; Mohamad, Dasmawati; Hasan, Habsah; Seeni, Azman; Rahman, Rosliza Abdul

2015-04-01

In this study, we report the structural morphology of a zinc oxide (ZnO) sample and antibacterial application of the ZnO structures in calamine lotion. Antibacterial activities of the calamine lotion towards Staphylococcus aureus and Pseudomonas aeruginosa were investigated. The structural morphology of ZnO sample was studied using a transmission electron microscope (TEM) and a field-emission scanning electron microscope (FESEM). The morphologies of the ZnO structure consisted of many rod and spherical structures. The particle sizes of the sample ranged from 40 nm to 150 nm. A calamine lotion was prepared through mixing the ZnO structures with other constituents in suitable proportion. The energy-dispersive x-ray spectroscopy (EDS) revealed the presence of large amount of ZnO structures whiles the X-ray diffraction (XRD) results showed a good crystalline property of ZnO in the calamine lotion mixture. The morphological structures of ZnO were found to remain unchanged in the calamine lotion mixture through FESEM imaging. In the antibacterial test, prepared calamine lotion exhibited a remarkable bacterial inhibition on Staphylococcus aureus and Pseudomonas aeruginosa after 24 h of treatment. The bactericidal capability of calamine lotion was largely due to the presence of ZnO structures which induce high toxicity and killing effect on the bacteria.

Hypoglycemic neuronal death is triggered by glucose reperfusion and activation of neuronal NADPH oxidase

PubMed Central

Suh, Sang Won; Gum, Elizabeth T.; Hamby, Aaron M.; Chan, Pak H.; Swanson, Raymond A.

2007-01-01

Hypoglycemic coma and brain injury are potential complications of insulin therapy. Certain neurons in the hippocampus and cerebral cortex are uniquely vulnerable to hypoglycemic cell death, and oxidative stress is a key event in this cell death process. Here we show that hypoglycemia-induced oxidative stress and neuronal death are attributable primarily to the activation of neuronal NADPH oxidase during glucose reperfusion. Superoxide production and neuronal death were blocked by the NADPH oxidase inhibitor apocynin in both cell culture and in vivo models of insulin-induced hypoglycemia. Superoxide production and neuronal death were also blocked in studies using mice or cultured neurons deficient in the p47phox subunit of NADPH oxidase. Chelation of zinc with calcium disodium EDTA blocked both the assembly of the neuronal NADPH oxidase complex and superoxide production. Inhibition of the hexose monophosphate shunt, which utilizes glucose to regenerate NADPH, also prevented superoxide formation and neuronal death, suggesting a mechanism linking glucose reperfusion to superoxide formation. Moreover, the degree of superoxide production and neuronal death increased with increasing glucose concentrations during the reperfusion period. These results suggest that high blood glucose concentrations following hypoglycemic coma can initiate neuronal death by a mechanism involving extracellular zinc release and activation of neuronal NADPH oxidase. PMID:17404617

Radical-scavenging activity, protective effect against lipid peroxidation and mineral contents of monofloral Cuban honeys.

PubMed

Alvarez-Suarez, José M; Giampieri, Francesca; Damiani, Elisabetta; Astolfi, Paola; Fattorini, Daniele; Regoli, Francesco; Quiles, José L; Battino, Maurizio

2012-03-01

Several monofloral Cuban honeys were analyzed to determine their free radical-scavenging activity and from this the total antioxidant content was estimated. The protective effect against lipid peroxidation in an in vitro model of rat liver homogenates was evaluated and, lastly, the mineral content of the honeys, which can be related to the maintenance of intracellular oxidative balance, was determined. The scavenging capacities against hydroxyl and superoxide radicals were determined using the spin-trapping technique and the hypoxanthine/xanthine oxidase assay, respectively. Lipid peroxidation was evaluated through the production of TBARS and hydroperoxides. All honeys tested showed potential antioxidant activity with Linen vine displaying the highest scavenging capacity towards the DPPH, hydroxyl and superoxide radicals, while the least efficient was Christmas vine honey. Honeys also inhibited, in a concentration-dependent mode, lipid peroxidation in rat liver homogenates, with Linen vine resulting the best while the least effective was Christmas vine honey. The ability to scavenge free radicals and protect against lipid peroxidation may contribute to the ability of certain Cuban honeys to help in preventing/reducing some inflammatory diseases in which oxidative stress is involved. A total of eight minerals were identified and quantified as follows: cadmium, chromium, copper, nickel, iron, manganese, lead, and zinc. Minerals found in higher concentrations were iron, zinc and manganese.

Plectranthus amboinicus leaf extract mediated synthesis of zinc oxide nanoparticles and its control of methicillin resistant Staphylococcus aureus biofilm and blood sucking mosquito larvae

NASA Astrophysics Data System (ADS)

Vijayakumar, S.; Vinoj, G.; Malaikozhundan, B.; Shanthi, S.; Vaseeharan, B.

2015-02-01

In this study, zinc oxide nanoparticles were biologically synthesized using the leaf extract of Plectranthus amboinicus (Pam-ZnO NPs). The synthesized Pam-ZnO NPs were characterized by UV-Vis spectrophotometer, FTIR, TEM and XRD analysis. TEM analysis of Pam-ZnO NPs showed the average size of about 20-50 nm. Pam-ZnO NPs control the growth of methicillin-resistant Staphylococcus aureus biofilms (MRSA ATCC 33591) at the concentration of 8-10 μg/ml. Confocal laser scanning microscope (CLSM) images revealed that Pam-ZnO NPs strongly inhibited the biofilm forming ability of S. aureus. In addition, Pam-ZnO NPs showed 100% mortality of fourth instar mosquito larvae of Anopheles stephensi, Culex quinquefasciatus and Culex tritaeniorhynchus at the concentration of 8 and 10 μg/ml. The histopathological studies of Pam-ZnO NPs treated A. stephensi and C. quinquefasciatus larvae revealed the presence of damaged cells and tissues in the mid-gut. The damaged tissues suffered major changes including rupture and disintegration of epithelial layer and cellular vacuolization. The present study conclude that Pam-ZnO NPs showed effective control of S. aureus biofilms and mosquito larvae by damaging the mid gut cells.

Low capping group surface density on zinc oxide nanocrystals.

PubMed

Valdez, Carolyn N; Schimpf, Alina M; Gamelin, Daniel R; Mayer, James M

2014-09-23

The ligand shell of colloidal nanocrystals can dramatically affect their stability and reaction chemistry. We present a methodology to quantify the dodecylamine (DDA) capping shell of colloidal zinc oxide nanocrystals in a nonpolar solvent. Using NMR spectroscopy, three different binding regimes are observed: strongly bound, weakly associated, and free in solution. The surface density of bound DDA is constant over a range of nanocrystal sizes, and is low compared to both predictions of the number of surface cations and maximum coverages of self-assembled monolayers. The density of strongly bound DDA ligands on the as-prepared ZnO NCs is 25% of the most conservative estimate of the maximum surface DDA density. Thus, these NCs do not resemble the common picture of a densely capped surface ligand layer. Annealing the ZnO NCs in molten DDA for 12 h at 160 °C, which is thought to remove surface hydroxide groups, resulted in a decrease of the weakly associated DDA and an increase in the density of strongly bound DDA, to ca. 80% of the estimated density of a self-assembled monolayer on a flat ZnO surface. These findings suggest that as-prepared nanocrystal surfaces contain hydroxide groups (protons on the ZnO surfaces) that inhibit strong binding of DDA.

Green synthesised zinc oxide nanostructures through Periploca aphylla extract shows tremendous antibacterial potential against multidrug resistant pathogens.

PubMed

Abbas, Fazal; Maqbool, Qaisar; Nazar, Mudassar; Jabeen, Nyla; Hussain, Syed Zaheer; Anwaar, Sadaf; Mehmood, Nasir; Sheikh, Muhammad Saleem; Hussain, Talib; Iftikhar, Sidra

2017-12-01

To grapple with multidrug resistant bacterial infections, implementations of antibacterial nanomedicines have gained prime attention of the researchers across the globe. Nowadays, zinc oxide (ZnO) at nano-scale has emerged as a promising antibacterial therapeutic agent. Keeping this in view, ZnO nanostructures (ZnO-NS) have been synthesised through reduction by P. aphylla aqueous extract without the utilisation of any acid or base. Structural examinations via scanning electron microscopy (SEM) and X-ray diffraction have revealed pure phase morphology with highly homogenised average particle size of 18 nm. SEM findings were further supplemented by transmission electron microscopy examinations. The characteristic Zn-O peak has been observed around 363 nm using ultra-violet-visible spectroscopy. Fourier-transform infrared spectroscopy examination has also confirmed the formation of ZnO-NS through detection of Zn-O bond vibration frequencies. To check the superior antibacterial activity of ZnO-NS, the authors' team has performed disc diffusion assay and colony forming unit testing against multidrug resistant E. coli, S. marcescens and E. cloacae . Furthermore, protein kinase inhibition assay and cytotoxicity examinations have revealed that green fabricated ZnO-NS are non-hazardous, economical, environmental friendly and possess tremendous potential to treat lethal infections caused by multidrug resistant pathogens.

Diabetes-induced hepatic pathogenic damage, inflammation, oxidative stress, and insulin resistance was exacerbated in zinc deficient mouse model.

PubMed

Zhang, Chi; Lu, Xuemian; Tan, Yi; Li, Bing; Miao, Xiao; Jin, Litai; Shi, Xue; Zhang, Xiang; Miao, Lining; Li, Xiaokun; Cai, Lu

2012-01-01

Zinc (Zn) deficiency often occurs in the patients with diabetes. Effects of Zn deficiency on diabetes-induced hepatic injury were investigated. Type 1 diabetes was induced in FVB mice with multiple low-dose streptozotocin. Hyperglycemic and age-matched control mice were treated with and without Zn chelator, N,N,N',N'-tetrakis (2-pyridylemethyl) ethylenediamine (TPEN), at 5 mg/kg body-weight daily for 4 months. Hepatic injury was examined by serum alanine aminotransferase (ALT) level and liver histopathological and biochemical changes. Hepatic Zn deficiency (lower than control level, p<0.05) was seen in the mice with either diabetes or TPEN treatment and more evident in the mice with both diabetes and TPEN. Zn deficiency exacerbated hepatic injuries, shown by further increased serum ALT, hepatic lipid accumulation, inflammation, oxidative damage, and endoplasmic reticulum stress-related cell death in Diabetes/TPEN group compared to Diabetes alone. Diabetes/TPEN group also showed a significant decrease in nuclear factor-erythroid 2-related factor 2 (Nrf2) expression and transcription action along with significant increases in Akt negative regulators, decrease in Akt and GSK-3β phosphorylation, and increase in nuclear accumulation of Fyn (a Nrf2 negative regulator). In vitro study with HepG2 cells showed that apoptotic effect of TPEN at 0.5-1.0 µM could be completely prevented by simultaneous Zn supplementation at the dose range of 30-50 µM. Zn is required for maintaining Akt activation by inhibiting the expression of Akt negative regulators; Akt activation can inhibit Fyn nuclear translocation to export nuclear Nrf2 to cytoplasm for degradation. Zn deficiency significantly enhanced diabetes-induced hepatic injury likely through down-regulation of Nrf2 function.

Antibacterial Activity of Dental Composites Containing Zinc Oxide Nanoparticles

PubMed Central

Sevinç, Berdan Aydin; Hanley, Luke

2010-01-01

The resin-based dental composites commonly used in restorations result in more plaque accumulation than other materials. Bacterial biofilm growth contributes to secondary caries and failure of resin-based dental composites. Methods to inhibit biofilm growth on dental composites have been sought for several decades. It is demonstrated here that zinc oxide nanoparticles (ZnO-NPs) blended at 10% (w/w) fraction into dental composites display antimicrobial activity and reduce growth of bacterial biofilms by roughly 80% for a single-species model dental biofilm. Antibacterial effectiveness of ZnO-NPs was assessed against Streptococcus sobrinus ATCC 27352 grown both planktonically and as biofilms on composites. Direct contact inhibition was observed by scanning electron microscopy and confocal laser scanning microscopy while biofilm formation was quantified by viable counts. An 80% reduction in bacterial counts was observed with 10% ZnO-NP-containing composites compared with their unmodified counterpart, indicating a statistically significant suppression of biofilm growth. Although, 20% of the bacterial population survived and could form a biofilm layer again, 10% ZnO-NP-containing composites maintained at least some inhibitory activity even after the third generation of biofilm growth. Microscopy demonstrated continuous biofilm formation for unmodified composites after one day growth, but only sparsely distributed biofilms formed on 10% ZnO-NP-containing composites. The minimum inhibitory concentration of ZnO-NPs suspended in S. sobrinus planktonic culture was 50 μg/ml. 10% ZnO-NP-containing composites qualitatively showed less biofilm after one day anaerobic growth of a three-species initial colonizer biofilm after when compared to unmodified composites, but did not significantly reduce growth after three days. PMID:20225252

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

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

Chen, Dazheng; Zhang, Chunfu, E-mail: cfzhang@xidian.edu.cn; Wang, Zhizhe

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 slightlymore » 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.« less

Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora

PubMed Central

Hsieh, Heidi; Vignesh, Kavitha Subramanian; Deepe, George S.; Choubey, Divaker; Shertzer, Howard G.; Genter, Mary Beth

2016-01-01

Zinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200 μM ZG for 0-24 h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1β protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons. PMID:27179668

Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora.

PubMed

Hsieh, Heidi; Vignesh, Kavitha Subramanian; Deepe, George S; Choubey, Divaker; Shertzer, Howard G; Genter, Mary Beth

2016-09-01

Zinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200μM ZG for 0-24h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1β protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons. Copyright © 2016 Elsevier Ltd. All rights reserved.

Valproic acid attenuates acute lung injury induced by ischemia-reperfusion in rats.

PubMed

Wu, Shu-Yu; Tang, Shih-En; Ko, Fu-Chang; Wu, Geng-Chin; Huang, Kun-Lun; Chu, Shi-Jye

2015-06-01

Evidence reveals that histone deacetylase (HDAC) inhibition has potential for the treatment of inflammatory diseases. The protective effect of HDAC inhibition involves multiple mechanisms. Heme oxygenase-1 (HO-1) is protective in lung injury as a key regulator of antioxidant response. The authors examined whether HDAC inhibition provided protection against ischemia-reperfusion (I/R) lung injury in rats by up-regulating HO-1 activity. Acute lung injury was induced by producing 40 min of ischemia followed by 60 min of reperfusion in isolated perfused rat lungs. The rats were randomly allotted to control group, I/R group, or I/R + valproic acid (VPA) group with or without an HO-1 activity inhibitor (zinc protoporphyrin IX) (n = 6 per group). I/R caused significant increases in the lung edema, pulmonary arterial pressure, lung injury scores, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 concentrations in bronchoalveolar lavage fluid. Malondialdehyde levels, carbonyl contents, and myeloperoxidase-positive cells in lung tissue were also significantly increased. I/R stimulated the degradation of inhibitor of nuclear factor-κB-α, nuclear translocation of nuclear factor-κB, and up-regulation of HO-1 activity. Furthermore, I/R decreased B-cell lymphoma-2, heat shock protein 70, acetylated histone H3 protein expression, and increased the caspase-3 activity in the rat lungs. In contrast, VPA treatment significantly attenuated all the parameters of lung injury, oxidative stress, apoptosis, and inflammation. In addition, VPA treatment also enhanced HO-1 activity. Treatment with zinc protoporphyrin IX blocked the protective effect of VPA. VPA protected against I/R-induced lung injury. The protective mechanism may be partly due to enhanced HO-1 activity following HDAC inhibition.

Graphene-Based Transparent Electrodes for Dye Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Al-Rawashdeh, Nathir A. F.; Albiss, Borhan A.; Yousef, Mo'ath H. I.

2018-02-01

Several Zinc Oxide (ZnO) photo-anodes were prepared with different morphologies. For each morphology, two composites containing graphene oxide (GO) were prepared. ZnO sheet-flowers attained the highest efficiency among control samples, owing to the light diffraction that may be caused by such morphology. On the other hand, ZnO rods achieved lower performance than ZnO sheet-flowers, but higher than ZnO flowers, due to their porosity and structure, which may scatter light effectively. The effect of including GO in the photoanode matrix was studied and the results demonstrate a significant increase in short circuit current density (JSC). The addition of GO suggested an overall positive effect on cell performance, where samples of ZnO rods and Flowers had the most significant increase in their performance, due to the inhibition of charge recombination by GO.

Immobilization of bacterial S-layer proteins from Caulobacter crescentus on iron oxide-based nanocomposite: synthesis and spectroscopic characterization of zincite-coated Fe₂O₃ nanoparticles.

PubMed

Habibi, Neda

2014-05-05

Zinc oxide was coated on Fe2O3 nanoparticles using sol-gel spin-coating. Caulobacter crescentus have a crystalline surface layer (S-layer), which consist of one protein or glycoprotein species. The immobilization of bacterial S-layers obtained from C. crescentus on zincite-coated nanoparticles of iron oxide was investigated. The SDS PAGE results of S-layers isolated from C. crescentus showed the weight of 50 KDa. Nanoparticles of the Fe2O3 and zinc oxide were synthesized by a sol-gel technique. Fe2O3 nanoparticles with an average size of 50 nm were successfully prepared by the proper deposition of zinc oxide onto iron oxide nanoparticles surface annealed at 450 °C. The samples were characterized by field-emission scanning electron microscope (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). Copyright © 2014 Elsevier B.V. All rights reserved.

Dietary Enterococcus faecium NCIMB 10415 and Zinc Oxide Stimulate Immune Reactions to Trivalent Influenza Vaccination in Pigs but Do Not Affect Virological Response upon Challenge Infection

PubMed Central

Wang, Zhenya; Burwinkel, Michael; Chai, Weidong; Lange, Elke; Blohm, Ulrike; Breithaupt, Angele; Hoffmann, Bernd; Twardziok, Sven; Rieger, Juliane; Janczyk, Pawel; Pieper, Robert; Osterrieder, Nikolaus

2014-01-01

Swine influenza viruses (SIV) regularly cause significant disease in pigs worldwide. Since there is no causative treatment of SIV, we tested if probiotic Enterococcus (E.) faecium NCIMB 10415 or zinc (Zn) oxide as feed supplements provide beneficial effects upon SIV infection in piglets. Seventy-two weaned piglets were fed three different diets containing either E. faecium or different levels of Zn (2500 ppm, Znhigh; 50 ppm, Znlow). Half of the piglets were vaccinated intramuscularly (VAC) twice with an inactivated trivalent SIV vaccine, while all piglets were then infected intranasally with H3N2 SIV. Significantly higher weekly weight gains were observed in the E. faecium group before virus infection, and piglets in Znhigh and E. faecium groups gained weight after infection while those in the control group (Znlow) lost weight. Using ELISA, we found significantly higher H3N2-specific antibody levels in the E. faecium+VAC group 2 days before and at the day of challenge infection as well as at 4 and 6 days after challenge infection. Higher hemagglutination inhibition (HI) titers were also observed in the Znhigh+VAC and E. faecium+VAC groups at 0, 1 and 4 days after infection. However, there were no significant differences in virus shedding and lung lesions between the dietary groups. Using flow cytometry analysis significantly higher activated T helper cells and cytotoxic T lymphocyte percentages in the PBMCs were detected in the Znhigh and E. faecium groups at single time points after infection compared to the Znlow control group, but no prolonged effect was found. In the BAL cells no influence of dietary supplementation on immune cell percentages could be detected. Our results suggest that feeding high doses of zinc oxide and particularly E. faecium could beneficially influence humoral immune responses after vaccination and recovery from SIV infection, but not affect virus shedding and lung pathology. PMID:24489827

Dietary Enterococcus faecium NCIMB 10415 and zinc oxide stimulate immune reactions to trivalent influenza vaccination in pigs but do not affect virological response upon challenge infection.

PubMed

Wang, Zhenya; Burwinkel, Michael; Chai, Weidong; Lange, Elke; Blohm, Ulrike; Breithaupt, Angele; Hoffmann, Bernd; Twardziok, Sven; Rieger, Juliane; Janczyk, Pawel; Pieper, Robert; Osterrieder, Nikolaus

2014-01-01

Swine influenza viruses (SIV) regularly cause significant disease in pigs worldwide. Since there is no causative treatment of SIV, we tested if probiotic Enterococcus (E.) faecium NCIMB 10415 or zinc (Zn) oxide as feed supplements provide beneficial effects upon SIV infection in piglets. Seventy-two weaned piglets were fed three different diets containing either E. faecium or different levels of Zn (2500 ppm, Zn(high); 50 ppm, Zn(low)). Half of the piglets were vaccinated intramuscularly (VAC) twice with an inactivated trivalent SIV vaccine, while all piglets were then infected intranasally with H3N2 SIV. Significantly higher weekly weight gains were observed in the E. faecium group before virus infection, and piglets in Zn(high) and E. faecium groups gained weight after infection while those in the control group (Zn(low)) lost weight. Using ELISA, we found significantly higher H3N2-specific antibody levels in the E. faecium+VAC group 2 days before and at the day of challenge infection as well as at 4 and 6 days after challenge infection. Higher hemagglutination inhibition (HI) titers were also observed in the Zn(high)+VAC and E. faecium+VAC groups at 0, 1 and 4 days after infection. However, there were no significant differences in virus shedding and lung lesions between the dietary groups. Using flow cytometry analysis significantly higher activated T helper cells and cytotoxic T lymphocyte percentages in the PBMCs were detected in the Zn(high) and E. faecium groups at single time points after infection compared to the Zn(low) control group, but no prolonged effect was found. In the BAL cells no influence of dietary supplementation on immune cell percentages could be detected. Our results suggest that feeding high doses of zinc oxide and particularly E. faecium could beneficially influence humoral immune responses after vaccination and recovery from SIV infection, but not affect virus shedding and lung pathology.

The reduction of graphene oxide by zinc powder to produce a zinc oxide-reduced graphene oxide hybrid and its superior photocatalytic activity

NASA Astrophysics Data System (ADS)

Sarkar, Sanjit; Basak, Durga

2013-03-01

We have synthesized for the first time ZnO/rGO hybrids from metal zinc and GO using hydrothermal technique without adding further reducing agent. The photocatalytic property of ZnO-rGO reveals that the hybrid for 50 mg of GO has the highest activity, causing a 94% degradation of methyl orange compared to 70% by only ZnO. The consistent quenching and a gradual decrease in the decay life time of the emission at ˜500 nm as the rGO content increases indicates the interfacial charge transfer process between ZnO and rGO by the defect states responsible for green emission.

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors

NASA Astrophysics Data System (ADS)

Yang, Jyun-Bao; Chang, Ting-Chang; Huang, Jheng-Jie; Chen, Yu-Chun; Chen, Yu-Ting; Tseng, Hsueh-Chih; Chu, Ann-Kuo; Sze, Simon M.

2014-04-01

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Effect of Zinc Oxide Film Deposition Position on the Characteristics of Zinc Oxide Thin Film Transistors Fabricated by Low-Temperature Magnetron Sputtering

NASA Astrophysics Data System (ADS)

Takechi, Kazushige; Nakata, Mitsuru; Eguchi, Toshimasa; Otsuki, Shigeyoshi; Yamaguchi, Hirotaka; Kaneko, Setsuo

2008-09-01

We report on the effect of zinc oxide (ZnO) film deposition position on the characteristics of ZnO thin-film transistors (TFTs) fabricated by magnetron sputtering with no intentional heating of the substrate. We evaluate the properties of ZnO (channel semiconductor) films deposited at various positions with respect to the target position. We show that the film deposition at a position off-centered from the target results in good TFT characteristics. This might be due to the fact that the off-centered deposition position is effective for suppressing the effect of energetic negative ions in the plasma.

Mixed metal oxides for dye-sensitized solar cell using zinc titanium layered double hydroxide as precursor

NASA Astrophysics Data System (ADS)

Liu, Jianqiang; Qin, Yaowei; Zhang, Liangji; Xiao, Hongdi; Song, Jianye; Liu, Dehe; Leng, Mingzhe; Hou, Wanguo; Du, Na

2013-12-01

Mixed metal oxides (MMO) are always obtained from layered double hydroxide (LDH) by thermal decomposition. In the present work, a zinc titanium LDH with the zinc titanium molar ratio of 4.25 was prepared by urea method and ZnO-based mixed oxides were obtained by calcining at or over 500°C. The MMO was used as electrodes for dye sensitized solar cell (DSSC). The cells constructed by films of prepared composite materials using a N719 as dye were prepared. The efficiency values of these cells are 0.691%, 0.572% and 0.302% with MMO prepared at 500, 600 and 700°C, respectively.

Tuning the surface morphology of aluminium doped zinc oxide thin films by arrayed nanorods through chemical growth process

NASA Astrophysics Data System (ADS)

Devasia, Sebin; Anila, E. I.

2018-04-01

Here we report the growth and characterization of chemically grown aluminium doped zinc oxide nanorods on seed layers. The seed layers were prepared by chemical spray pyrolysis which acted as the growth centers. The growth duration of nanorods were varied from 3h to 12h in steps of 3h. Further, investigations on their structural, morphological, electrical and optical properties. The SEM images confirmed the hexagonal shaped nanorod arrays grown on the seed layers. Later, the x-ray diffraction measurements revealed the pure zinc oxide phase of the samples. Photoluminescence and photoconductivity studies were carried out to analyze the potential of its optoelectronic properties.

Sonochemically synthesized iron-doped zinc oxide nanoparticles: Influence of precursor composition on characteristics

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

Roy, Anirban; Maitra, Saikat; Ghosh, Sobhan

Highlights: • Sonochemical synthesis of iron-doped zinc oxide nanoparticles. • Green synthesis without alkali at room temperature. • Characterization by UV–vis spectroscopy, FESEM, XRD and EDX. • Influence of precursor composition on characteristics. • Composition and characteristics are correlated. - Abstract: Iron-doped zinc oxide nanoparticles have been synthesized sonochemically from aqueous acetyl acetonate precursors of different proportions. Synthesized nanoparticles were characterized with UV–vis spectroscopy, X-ray diffraction and microscopy. Influences of precursor mixture on the characteristics have been examined and modeled. Linear correlations have been proposed between dopant dosing, extent of doping and band gap energy. Experimental data corroborated with themore » proposed models.« less

Down-top nanofabrication of binary (CdO)x (ZnO)1–x nanoparticles and their antibacterial activity

PubMed Central

Al-Hada, Naif Mohammed; Mohamed Kamari, Halimah; Abdullah, Che Azurahanim Che; Saion, Elias; Shaari, Abdul H; Talib, Zainal Abidin; Matori, Khamirul Amin

2017-01-01

In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1–x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO)x (ZnO)1–x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO)x (ZnO)1–x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO)x (ZnO)1–x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precursor increased from x=0.20 to x=0.80, as observed by TEM results. The surface composition and valance state of the prepared product NPs were determined by X-ray photoelectron spectroscopy (XPS) analyses. Diffuse UV–visible reflectance spectra were used to determine the optical band gap through the Kubelka–Munk equation; the energy band gap was found to decrease for CdO from 2.92 to 2.82 eV and for ZnO from 3.22 to 3.11 eV with increasing x value. Additionally, photoluminescence (PL) spectra revealed that the intensity in PL increased with an increase in particle size. In addition, the antibacterial activity of binary oxide NP was carried out in vitro against Escherichia coli ATCC 25922 Gram (−ve), Salmonella choleraesuis ATCC 10708, and Bacillus subtilis UPMC 1175 Gram (+ve). This study indicated that the zone of inhibition of 21 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175. PMID:29200844

Alterations in protein kinase C activity and processing during zinc-deficiency-induced cell death.

PubMed

Chou, Susan S; Clegg, Michael S; Momma, Tony Y; Niles, Brad J; Duffy, Jodie Y; Daston, George P; Keen, Carl L

2004-10-01

Protein kinases C (PKCs) are a family of serine/threonine kinases that are critical for signal transduction pathways involved in growth, differentiation and cell death. All PKC isoforms have four conserved domains, C1-C4. The C1 domain contains cysteine-rich finger-like motifs, which bind two zinc atoms. The zinc-finger motifs modulate diacylglycerol binding; thus, intracellular zinc concentrations could influence the activity and localization of PKC family members. 3T3 cells were cultured in zinc-deficient or zinc-supplemented medium for up to 32 h. Cells cultured in zinc-deficient medium had decreased zinc content, lowered cytosolic classical PKC activity, increased caspase-3 processing and activity, and reduced cell number. Zinc-deficient cytosols had decreased activity and expression levels of PKC-alpha, whereas PKC-alpha phosphorylation was not altered. Inhibition of PKC-alpha with Gö6976 had no effect on cell number in the zinc-deficient group. Proteolysis of the novel PKC family member, PKC-delta, to its 40-kDa catalytic fragment occurred in cells cultured in the zinc-deficient medium. Occurrence of the PKC-delta fragment in mitochondria was co-incident with caspase-3 activation. Addition of the PKC-delta inhibitor, rottlerin, or zinc to deficient medium reduced or eliminated proteolysis of PKC-delta, activated caspase-3 and restored cell number. Inhibition of caspase-3 processing by Z-DQMD-FMK (Z-Asp-Gln-Met-Asp-fluoromethylketone) did not restore cell number in the zinc-deficient group, but resulted in processing of full-length PKC-delta to a 56-kDa fragment. These results support the concept that intracellular zinc concentrations influence PKC activity and processing, and that zinc-deficiency-induced apoptosis occurs in part through PKC-dependent pathways.

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

Tsou, Tsui-Chun, E-mail: tctsou@nhri.org.tw; Liou, Saou-Hsing; Yeh, Szu-Ching

Our previous studies indicated that zinc induced inflammatory response in both vascular endothelial cells and promonocytes. Here, we asked if other metals could cause the similar effect on vascular endothelial cells and tried to determine its underlying mechanism. Following screening of fifteen metals, zinc and nickel were identified with a marked proinflammatory effect, as determined by ICAM-1 and IL-8 induction, on human umbilical vein endothelial cells (HUVECs). Inhibiting protein expression of myeloid differentiation primary response protein-88 (MyD88), a Toll-like receptor (TLR) adaptor acting as a TLR-signaling transducer, significantly attenuated the zinc/nickel-induced inflammatory response, suggesting the critical roles of TLRs inmore » the inflammatory response. Blockage of TLR-4 signaling by CLI-095, a TLR-4 inhibitor, completely inhibited the nickel-induced ICAM-1 and IL-8 expression and NFκB activation. The same CLI-095 treatment significantly blocked the zinc-induced IL-8 expression, however with no significant effect on the ICAM-1 expression and a minor inhibitory effect on the NFκB activation. The finding demonstrated the differential role of TLR-4 in regulation of the zinc/nickel-induced inflammatory response, where TLR-4 played a dominant role in NFκB activation by nickel, but not by zinc. Moreover, inhibition of NFκB by adenovirus-mediated IκBα expression and Bay 11-7025, an inhibitor of cytokine-induced IκB-α phosphorylation, significantly attenuated the zinc/nickel-induced inflammatory responses, indicating the critical of NFκB in the process. The study demonstrates the crucial role of TLRs in the zinc/nickel-induced inflammatory response in vascular endothelial cells and herein deciphers a potential important difference in NFκB activation via TLRs. The study provides a molecular basis for linkage between zinc/nickel exposure and pathogenesis of the metal-related inflammatory vascular disease. - Highlights: • Both zinc and nickel cause ICAM-1/IL‑8 expression in endothelial cells via TLRs. • Nickel induces the inflammatory responses via a TLR-4/NF-κB pathway. • Zinc causes the inflammatory responses via a broader TLRs/NF-κB signaling. • Nickel shows a significantly higher inflammatory effect than zinc. • NF-κB activation is the primary mechanism involved in the inflammatory responses.« less

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...

Application of zinc oxide quantum dots in food safety

USDA-ARS?s Scientific Manuscript database

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...

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.

Meals and dephytinization affect calcium and zinc absorption in Nigerian children with rickets

USDA-ARS?s Scientific Manuscript database

Nutritional rickets resulting from calcium insufficiency is common in Nigeria, and high dietary phytate is thought to inhibit calcium and zinc absorption. We compared the effects of a high-phytate meal and enzymatic dephytinization on calcium and zinc absorption in Nigerian children with and without...

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

NASA Astrophysics Data System (ADS)

Perumal, R.; Hassan, Z.

2016-06-01

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

Advanced Polymer Systems for Defence Applications: Power Generation, Protection and Sensing

DTIC Science & Technology

2014-05-01

oxide nanoparticles synthesized via non-sol-gel methods, e.g., via a flame process; and, (d) Amine sensors based on silver nanoparticle- doped ...Hongmin Chen, Guodong Chen, Xiaohong Gu, James L. Lee, E. E. Abdel-Hady, Y. C. Jean. Free Volumes, Glass Transitions, and Cross-Links in Zinc Oxide ...properties in a system of zinc oxide (ZnO) nanoparticles (20 nm) dispersed in waterborne polyurethane (WBPU) were measured using positron annihilation

Status of zinc injection in PWRs

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

Bergmann, C.A.

1995-03-01

Based on laboratory and other studies, it was concluded that zinc addition in a PWR primary coolant should result in reduced Alloy 600 PWSCC and general corrosion rates of the materials of construction. Because of these positive results, a Westinghouse Owner`s Subgroup, EPRI, and Westinghouse provided funds to continue the development and application of zinc in an operating plant. As part of the program, Southern Operating Nuclear Company agreed to operate the Farley 2 plant with zinc addition as a demonstration test of the effectiveness of zinc. Since zinc is incorporated in the corrosion oxide film on the primary systemmore » surfaces and Farley 2 is a mature plant, it was estimated that about 10 kgs of zinc would be needed to condition the plant before an equilibrium value in the coolant would be reached. The engineered aspects of a Zinc Addition and Monitoring System (ZAMS) considered such items as the constitutents, location, sizing and water supply of the ZAMS. Baseline data such as the PWSCC history of the Alloy 600 steam generator tubing, fuel oxide thickness, fuel crud deposits, radiation levels, and RCP seal leak-off rates were obtained before zinc addition is initiated. This presentation summarizes some of the work performed under the program, and the status of zinc injection in the Farley 2 plant.« less

Zinc-Containing Hydroxyapatite Enhances Cold-Light-Activated Tooth Bleaching Treatment In Vitro

PubMed Central

Shi, Xinchang

2017-01-01

Cold-light bleaching treatment has grown to be a popular tooth whitening procedure in recent years, but its side effect of dental enamel demineralization is a widespread problem. The aim of this study was to synthesize zinc-substituted hydroxyapatite as an effective biomaterial to inhibit demineralization or increase remineralization. We synthesized zinc-substituted hydroxyapatite containing different zinc concentrations and analysed the product using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive spectrometer (EDS). The biological assessment of Zn-HA was conducted by CCK-8 assay and bacterial inhibition tests. pH cycling was performed to estimate the effect of Zn-HA on the enamel surface after cold-light bleaching treatment. The XRD, FTIR, and EDS results illustrated that zinc ions and hydroxyapatite combined in two forms: (1) Zn2+ absorbed on the surface of HA crystal and (2) Zn2+ incorporated into the lattice of HA. The results indicated that 2% Zn-HA, 4% Zn-HA, and 8% Zn-HA effectively inhibited the growth of bacteria yet showed poor biocompatibility, whereas 1% Zn-HA positively affected osteoblast proliferation. The XRD and scanning electron microscopy (SEM) results showed that the use of Zn-HA in pH cycling is obviously beneficial for enamel remineralization. Zinc-substituted hydroxyapatite could be a promising biomaterial for use in cold-light bleaching to prevent enamel demineralization. PMID:29159178

Transparent and Flexible Zinc Tin Oxide Thin Film Transistors and Inverters using Low-pressure Oxygen Annealing Process

NASA Astrophysics Data System (ADS)

Lee, Kimoon; Kim, Yong-Hoon; Kim, Jiwan; Oh, Min Suk

2018-05-01

We report on the transparent and flexible enhancement-load inverters which consist of zinc tin oxide (ZTO) thin film transistors (TFTs) fabricated at low process temperature. To control the electrical characteristics of oxide TFTs by oxygen vacancies, we applied low-pressure oxygen rapid thermal annealing (RTA) process to our devices. When we annealed the ZTO TFTs in oxygen ambient of 2 Torr, they showed better electrical characteristics than those of the devices annealed in the air ambient of 760 Torr. To realize oxide thin film transistor and simple inverter circuits on flexible substrate, we annealed the devices in O2 of 2 Torr at 150° C and could achieve the decent electrical properties. When we used transparent conductive oxide electrodes such as indium zinc oxide (IZO) and indium tin oxide (ITO), our transparent and flexible inverter showed the total transmittance of 68% in the visible range and the voltage gain of 5. And the transition voltage in voltage transfer curve was located well within the range of operation voltage.

40 CFR 461.73 - New source performance standards. (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS BATTERY MANUFACTURING POINT SOURCE CATEGORY Zinc Subcategory § 461.73 New... subject to this subpart shall not exceed the standards set forth below: (1) Subpart G—Zinc Oxide Formed... units—mg/kg of zinc English units—pounds per 1,000,000 pounds of zinc Chromium 4.55 1.97 Mercury 2.82 1...

Preparation of Graphene-Zinc Oxide Nanostructure Composite for Carbon Monoxide Gas Sensing

NASA Astrophysics Data System (ADS)

Muchtar, Ahmad Rifqi; Septiani, Ni Luh Wulan; Iqbal, Muhammad; Nuruddin, Ahmad; Yuliarto, Brian

2018-03-01

A simple method to synthesize graphene-zinc oxide nanocomposite has been developed. A reduced graphene oxide-ZnO nanocomposite was prepared using a reflux method with ethylene glycol as medium. X-ray diffraction analysis, scanning electron microscopy, energy-dispersive spectrometry, and nitrogen adsorption-desorption measurements were used to characterize the resulting composite materials. The highest response of about 98% was observed when using pure ZnO at 300°C, while the second highest sensor response of about 96% was achieved by graphene-ZnO with 1:3 composition. It was found that the graphene-zinc oxide hybrid has potential to improve sensor performance at low temperature. The graphene-ZnO hybrid with 1:3 composition showed good response of 36% at 125°C, an operating temperature at which pure ZnO showed no response.

Preparation of Graphene-Zinc Oxide Nanostructure Composite for Carbon Monoxide Gas Sensing

NASA Astrophysics Data System (ADS)

Muchtar, Ahmad Rifqi; Septiani, Ni Luh Wulan; Iqbal, Muhammad; Nuruddin, Ahmad; Yuliarto, Brian

2018-07-01

A simple method to synthesize graphene-zinc oxide nanocomposite has been developed. A reduced graphene oxide-ZnO nanocomposite was prepared using a reflux method with ethylene glycol as medium. X-ray diffraction analysis, scanning electron microscopy, energy-dispersive spectrometry, and nitrogen adsorption-desorption measurements were used to characterize the resulting composite materials. The highest response of about 98% was observed when using pure ZnO at 300°C, while the second highest sensor response of about 96% was achieved by graphene-ZnO with 1:3 composition. It was found that the graphene-zinc oxide hybrid has potential to improve sensor performance at low temperature. The graphene-ZnO hybrid with 1:3 composition showed good response of 36% at 125°C, an operating temperature at which pure ZnO showed no response.

Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

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

Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli, E-mail: tgl@hust.edu.cn

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 usefulmore » approach to improve the performance of inverted polymer solar cells.« less

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine.

PubMed

Pires, C W; Lenzi, T L; Soares, F Z M; Rocha, R O

2018-05-12

This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine. Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05). The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures. Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

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

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content

PubMed Central

Crawford, Matthew A.; Tapscott, Timothy; Fitzsimmons, Liam F.; Liu, Lin; Reyes, Aníbal M.; Libby, Stephen J.; Trujillo, Madia; Fang, Ferric C.; Radi, Rafael

2016-01-01

ABSTRACT The four-cysteine zinc finger motif of the bacterial RNA polymerase regulator DksA is essential for protein structure, canonical control of the stringent response to nutritional limitation, and thiol-based sensing of oxidative and nitrosative stress. This interdependent relationship has limited our understanding of DksA-mediated functions in bacterial pathogenesis. Here, we have addressed this challenge by complementing ΔdksA Salmonella with Pseudomonas aeruginosa dksA paralogues that encode proteins differing in cysteine and zinc content. We find that four-cysteine, zinc-bound (C4) and two-cysteine, zinc-free (C2) DksA proteins are able to mediate appropriate stringent control in Salmonella and that thiol-based sensing of reactive species is conserved among C2 and C4 orthologues. However, variations in cysteine and zinc content determine the threshold at which individual DksA proteins sense and respond to reactive species. In particular, zinc acts as an antioxidant, dampening cysteine reactivity and raising the threshold of posttranslational thiol modification with reactive species. Consequently, C2 DksA triggers transcriptional responses in Salmonella at levels of oxidative or nitrosative stress normally tolerated by Salmonella expressing C4 orthologues. Inappropriate transcriptional regulation by C2 DksA increases the susceptibility of Salmonella to the antimicrobial effects of hydrogen peroxide and nitric oxide, and attenuates virulence in macrophages and mice. Our findings suggest that the redox-active sensory function of DksA proteins is finely tuned to optimize bacterial fitness according to the levels of oxidative and nitrosative stress encountered by bacterial species in their natural and host environments. PMID:27094335

Grape seed and skin extract reduces pancreas lipotoxicity, oxidative stress and inflammation in high fat diet fed rats.

PubMed

Aloui, Faten; Charradi, Kamel; Hichami, Aziz; Subramaniam, Selvakumar; Khan, Naim Akhtar; Limam, Ferid; Aouani, Ezzedine

2016-12-01

Obesity is related to an elevated risk of diabetes and the mechanisms whereby fat adversely affects the pancreas are poorly understood. We studied the effect of a high fat diet (HFD) on pancreas steatosis, oxidative stress and inflammation as well as the putative protection afforded by grape seed and skin extract (GSSE). HFD induced body weight gain, without affecting insulinemia, nor glycemia and dropped adiponectemia. HFD also provoked the ectopic deposition of cholesterol and triglyceride, and an oxidative stress characterized by increased lipoperoxidation and carbonylation, inhibition of antioxidant enzyme activities such as CAT, GPx and SOD, depletion of zinc and a concomitant increase in calcium and H 2 O 2 . HFD induced pro-inflammatory chemokines mRNA as RANTES and MCP1 as well as cytokines expression as TNFα, IL6 and IL1β. Importantly GSSE counteracted all the deleterious effects of HFD on pancreas in vivo i-e lipotoxicity, oxidative stress and inflammation. In conclusion, GSSE could find potential applications in fat-induced pancreas lipotoxicity and dysfunction. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Finger millet (Eleucine coracana) flour as a vehicle for fortification with zinc.

PubMed

Tripathi, Bhumika; Platel, Kalpana

2010-01-01

Millets, being less expensive compared to cereals and the staple for the poorer sections of population, could be the choice for fortification with micronutrients such as zinc. In view of this, finger millet, widely grown and commonly consumed in southern India, was explored as a vehicle for fortification with zinc in this investigation. Finger millet flour fortified with either zinc oxide or zinc stearate so as to provide 50mg zinc per kg flour, was specifically examined for the bioaccessibility of the fortified mineral, as measured by in vitro simulated gastrointestinal digestion procedure and storage stability. Addition of the zinc salts increased the bioaccessible zinc content by 1.5-3 times that of the unfortified flour. Inclusion of EDTA along with the fortified salt significantly enhanced the bioaccessibility of zinc from the fortified flours, the increase being three-fold. Inclusion of citric acid along with the zinc salt and EDTA during fortification did not have any additional beneficial effect on zinc bioaccessiblity. Moisture and free fatty acid contents of the stored fortified flours indicated the keeping quality of the same, up to 60 days. Both zinc oxide and zinc stearate were equally effective as fortificants, when used in combination with EDTA as a co-fortificant. The preparation of either roti or dumpling from the fortified flours stored up to 60 days did not result in any significant compromise in the bioaccessible zinc content. Thus, the present study has revealed that finger millet flour can effectively be used as a vehicle for zinc fortification to derive additional amounts of bioaccessible zinc, with reasonably good storage stability, to combat zinc deficiency. Copyright 2009 Elsevier GmbH. All rights reserved.

Role of nutritional zinc in the prevention of osteoporosis.

PubMed

Yamaguchi, Masayoshi

2010-05-01

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

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.

Zinc ion enhances GABA tea-mediated oxidative DNA damage.

PubMed

Chuang, Show-Mei; Wang, Hsueh-Fang; Hsiao, Ching-Chuan; Cherng, Shur-Hueih

2012-02-15

GABA tea is a tea product that contains a high level of γ-aminobutyric acid (GABA). Previous study has demonstrated a synergistic effect of GABA tea and copper ions on DNA breakage. This study further explored whether zinc (Zn), a nonredox metal, modulated DNA cleavage induced by GABA tea extract. In a cell-free system, Zn(2+) significantly enhanced GABA tea extract and (-)-epigallocatechin-3-gallate (EGCG)- or H(2)O(2)-induced DNA damage at 24 h of incubation. Additionally, low dosages of GABA tea extract (1-10 μg/mL) possessed pro-oxidant activity to increase H(2)O(2)/Zn(2+)-induced DNA cleavage in a dose-dependent profile. By use of various reactive oxygen scavengers, it was observed that glutathione, catalase, and potassium iodide effectively inhibited DNA degradation caused by the GABA tea extract/H(2)O(2)/Zn(2+) system. Moreover, the data showed that the GABA tea extract itself (0.5-5 mg/mL) could induce DNA cleavage in a long-term exposure (48 h). EGCG, but not the GABA tea extract, enhanced H(2)O(2)-induced DNA cleavage. In contrast, GABA decreased H(2)O(2)- and EGCG-induced DNA cleavage, suggesting that GABA might contribute the major effect on the antioxidant activity of GABA tea extract. Furthermore, a comet assay revealed that GABA tea extract (0.25 mg/mL) and GABA had antioxidant activity on H(2)O(2)-induced DNA breakage in human peripheral lymphocytes. Taken together, these findings indicate that GABA tea has the potential of both pro-oxidant and antioxidant. It is proposed that a balance between EGCG-induced pro-oxidation and GABA-mediated antioxidation may occur in a complex mixture of GABA tea extract.

Antibacterial activity and mechanism of action of zinc oxide nanoparticles against Campylobacter jejuni.

PubMed

Xie, Yanping; He, Yiping; Irwin, Peter L; Jin, Tony; Shi, Xianming

2011-04-01

The antibacterial effect of zinc oxide (ZnO) nanoparticles on Campylobacter jejuni was investigated for inhibition and inactivation of cell growth. The results showed that C. jejuni was extremely sensitive to treatment with ZnO nanoparticles. The MIC of ZnO nanoparticles for C. jejuni was determined to be 0.05 to 0.025 mg/ml, which is 8- to 16-fold lower than that for Salmonella enterica serovar Enteritidis and Escherichia coli O157:H7 (0.4 mg/ml). The action of ZnO nanoparticles against C. jejuni was determined to be bactericidal, not bacteriostatic. Scanning electron microscopy examination revealed that the majority of the cells transformed from spiral shapes into coccoid forms after exposure to 0.5 mg/ml of ZnO nanoparticles for 16 h, which is consistent with the morphological changes of C. jejuni under other stress conditions. These coccoid cells were found by ethidium monoazide-quantitative PCR (EMA-qPCR) to have a certain level of membrane leakage. To address the molecular basis of ZnO nanoparticle action, a large set of genes involved in cell stress response, motility, pathogenesis, and toxin production were selected for a gene expression study. Reverse transcription-quantitative PCR (RT-qPCR) showed that in response to treatment with ZnO nanoparticles, the expression levels of two oxidative stress genes (katA and ahpC) and a general stress response gene (dnaK) were increased 52-, 7-, and 17-fold, respectively. These results suggest that the antibacterial mechanism of ZnO nanoparticles is most likely due to disruption of the cell membrane and oxidative stress in Campylobacter.

Zinc oxide and titanium dioxide nanoparticles induce oxidative stress, inhibit growth, and attenuate biofilm formation activity of Streptococcus mitis.

PubMed

Khan, Shams Tabrez; Ahmad, Javed; Ahamed, Maqusood; Musarrat, Javed; Al-Khedhairy, Abdulaziz A

2016-06-01

Streptococcus mitis from the oral cavity causes endocarditis and other systemic infections. Rising resistance against traditional antibiotics amongst oral bacteria further aggravates the problem. Therefore, antimicrobial and antibiofilm activities of zinc oxide and titanium dioxide nanoparticles (NPs) synthesized and characterized during this study against S. mitis ATCC 6249 and Ora-20 were evaluated in search of alternative antimicrobial agents. ZnO and TiO2-NPs exhibited an average size of 35 and 13 nm, respectively. The IC50 values of ZnO and TiO2-NPs against S. mitis ATCC 6249 were 37 and 77 µg ml(-1), respectively, while the IC50 values against S. mitis Ora-20 isolate were 31 and 53 µg ml(-1), respectively. Live and dead staining, biofilm formation on the surface of polystyrene plates, and extracellular polysaccharide production show the same pattern. Exposure to these nanoparticles also shows an increase (26-83 %) in super oxide dismutase (SOD) activity. Three genes, namely bapA1, sodA, and gtfB like genes from these bacteria were identified and sequenced for quantitative real-time PCR analysis. An increase in sodA gene (1.4- to 2.4-folds) levels and a decrease in gtfB gene (0.5- to 0.9-folds) levels in both bacteria following exposure to ZnO and TiO2-NPs were observed. Results presented in this study verify that ZnO-NPs and TiO2-NPs can control the growth and biofilm formation activities of these strains at very low concentration and hence can be used as alternative antimicrobial agents for oral hygiene.

Thermal diffusion through amalgam and cement base: comparison of in vitro and in vivo measurements.

PubMed

Tibbetts, V R; Schnell, R J; Swartz, M L; Phillips, R W

1976-01-01

Thermal diffusion was measured in vitro and in vivo through amalgam and amalgam underlaid with bases of zinc phosphate, zinc oxide-eugenol, and calcium hydroxide cements. Although the magnitudes differed, there generally was good agreement between in vitro and in vivo data with respect to the relative rates of thermal diffusivity through amalgam restorations underlaid with bases of each of the three materials. In all tests, both in vitro and in vivo, the zinc oxide-eugenol base proved to be the best thermal insulator. Calcium hydroxide was the next best thermal barrier and was followed by zinc phosphate cement. In vitro tests indicated dentin to be a better thermal insulator than zinc phosphate cement but inferior to the zinc oxide-eugenol and calcium hydroxide base materials used here. Although a method has been presented here for the in vivo assessment of the efficacy of thermal insulating bases and a number of in vivo experiments were conducted, much research remains to be done in this area. Additional investigation is needed to better define the parameters of thermal change beneath various types of restoratives and also to establish more exactly the role of base thickness in providing thermal protection beneath clinical metallic restorations.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

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

1993-01-01

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub.3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

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

1993-10-19

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 [mu]m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO[sub 3]; and then indurating it at 800 to 900 C for a time sufficient to produce attrition-resistant granules.

Effect of Zinc and Melatonin on Oxidative Stress and Serum Inhibin-B Levels in a Rat Testicular Torsion-Detorsion Model.

PubMed

Semercioz, Atilla; Baltaci, Abdulkerim Kasim; Mogulkoc, Rasim; Avunduk, Mustafa Cihat

2017-12-01

The present study was aimed to examine the effects of 3-week zinc and melatonin administration on testicular tissue injury and serum Inhibin-B levels caused by unilateral testicular torsion-detorsion in rats. The study was performed on 60 Wistar Albino-type adult male rats. The animals were allocated to 6 groups in equal numbers. 1. Control; 2. Sham; 3. Ischemia-reperfusion; 4. Zinc + ischemia-reperfusion; 5. Melatonin + ischemia-reperfusion; 6. Zinc + melatonin + ischemia-reperfusion. Zinc and melatonin were administered before ischemia-reperfusion at doses of 5 and 3 mg/kg respectively, by intraperitoneal route for a period of 3 weeks. Testicular torsion-detorsion procedures consisted of ischemia for 1 h and then reperfusion for another hour of the left testis. Blood and testicular tissue samples were collected to analyze erythrocyte and tissue GSH and plasma and tissue MDA, Inhibin-B levels. The highest erythrocyte and testis GSH values were found in zinc, melatonin, and zinc + melatonin groups (p < 0.001). Torsion-detorsion group has significantly lower erythrocyte GSH levels and higher plasma MDA values (p < 0.001). Serum inhibin-B and spermatogenic activity levels in the torsion-detorsion group were also significantly lower than those in the other groups (p < 0.001). However, zinc-, melatonin-, and melatonin + zinc-supplemented groups have higher inhibin-B and spermatogenetic activity (p < 0.001). The results of the study show that zinc, melatonin, and melatonin + zinc administration partially restores the increased oxidative stress, as well as the reduced inhibin-B and spermatogenic activity levels in testes ischemia-reperfusion in rats. Suppressed inhibin-B levels in the testicular tissue may be a marker of oxidative stress.

UV-A induced oxidative stress is more prominent in naturally pigmented aged human RPE cells compared to non-pigmented human RPE cells independent of zinc treatment.

PubMed

Biesemeier, Antje; Kokkinou, Despina; Julien, Sylvie; Heiduschka, Peter; Berneburg, Mark; Bartz-Schmidt, Karl Ulrich; Schraermeyer, Ulrich

2008-02-27

To investigate the effects of zinc supplementation on human amelanotic (ARPE-19) and native pigmented retinal pigment epithelial cells (hRPE) under normal light conditions and after ultraviolet A light exposure. hRPE cells, containing both melanin and lipofuscin granules, were prepared from human donor eyes of 60-70 year old patients. Cells of the amelanotic ARPE-19 cell line and pigmented hRPE cells were treated with zinc chloride and subjected to oxidative stress by UV-A irradiation. Intracellular H(2)O(2) formation was measured using a fluorescence oxidation assay. Additionally, apoptosis and viability assays were performed. Control cells were treated identically except for irradiation and zinc supplementation. Under normal light conditions, zinc treated hRPE cells produced less H(2)O(2) than unsupplemented hRPE cells. Viability and apoptosis events did not change. After UV-A irradiation, ARPE and hRPE cells were greatly impaired in all tests performed compared to the non-irradiated controls. No differences were found after zinc supplementation. hRPE cells showed a higher apoptosis and mortality rate than non-pigmented cells when stressed by UV-A light. ARPE cells never showed any zinc related effects. In contrast, without irradiation, zinc supplementation reduced H(2)O(2) production in pigmented hRPE cells slightly. We did not find any zinc effect in irradiated hRPE cells. After UV light exposure, pigmented cells showed a higher apoptosis and mortality than cells lacking any pigmentation. We conclude that cells with pigmentation consisting of melanin and lipofuscin granules have more prooxidative than antioxidative capacity when stressed by UV light exposure compared to cells lacking any pigmentation.

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Crystallographic Location and Mutational Analysis of Zn and Cd Inhibitory Sites and Role of Lipidic Carboxylates in Rescuing Proton Path Mutants in Cytochrome c Oxidase†

PubMed Central

Qin, Ling; Mills, Denise A.; Hiser, Carrie; Murphree, Anna; Garavito, R. Michael; Ferguson-Miller, Shelagh; Hosler, Jonathan

2008-01-01

Cytochrome c oxidase (CcO) transfers protons from the inner surface of the enzyme to the buried O2 reduction site through two different pathways, termed K and D, and from the outer surface via an undefined route. These proton paths can be inhibited by metals such as zinc or cadmium, but the sites of inhibition have not been established. Anomalous difference Fourier analyses of Rhodobacter sphaeroides CcO crystals, with cadmium added, reveal metal binding sites that include the proposed initial proton donor/acceptor of the K pathway, Glu-101 of subunit II. Mutant forms of CcO that lack Glu-101II (E101A and E101A/H96A) exhibit low activity and eliminate metal binding at this site. Significant activity is restored to E101A and E101A/H96A by adding the lipophilic carboxylic compounds, arachidonic acid and cholic acid, but not by their non-carboxylic analogues. These amphipathic acids likely provide their carboxylic groups as substitute proton donors/acceptors in the absence of Glu-101II, as previously observed for arachidonic acid in mutants that alter Asp-132I of the D pathway. The activity of E101A/H96A is still inhibited by zinc, but this remaining inhibition is nearly eliminated by removal of subunit III, which is known to alter the D pathway. The results identify the Glu-101/His-96 site of subunit II as the site of metal binding that inhibits the uptake of protons into the K pathway and indicate that subunit III contributes to zinc binding and/or inhibition of the D pathway. By removing subunit III from E101A/H96A, thereby eliminating zinc inhibition of the uptake of protons from the inner surface of CcO, we confirm that an external zinc binding site is involved in inhibiting the backflow of protons to the active site. PMID:17477548

Experiments On Transparent Conductive Films For Spacecraft

NASA Technical Reports Server (NTRS)

Perez-Davis, Marla E.; Rutledge, Sharon K.; De Groh, Kim K.; Hung, Ching-Cheh; Malave-Sanabria, Tania; Hambourger, Paul; Roig, David

1995-01-01

Report describes experiments on thin, transparent, electrically conductive films made, variously, of indium tin oxide covered by magnesium fluoride (ITO/MgF2), aluminum-doped zinc oxide (AZO), or pure zinc oxide (ZnO). Films are candidates for application to such spacecraft components, including various optoelectronic devices and window surfaces that must be protected against buildup of static electric charge. On Earth, such films useful on heat mirrors, optoelectronic devices, gas sensors, and automotive and aircraft windows.

Effect of support size on the catalytic activity of metal-oxide-doped silica particles in the glycolysis of polyethylene terephthalate.

PubMed

Wi, Rinbok; Imran, Muhammad; Lee, Kyoung G; Yoon, Sun Hong; Cho, Bong Gyoo; Kim, Do Hyun

2011-07-01

Zinc oxide (ZnO) and cerium oxide (CeO2) nanoparticles were deposited on the surface of preformed silica spheres with diameters ranging from 60 to 750 nm. Ultrasonic irradiation was employed to promote the deposition of the metal oxide nanoparticles on the surface of silica. Silica-supported zinc oxide or cerium oxide was used as a catalyst in the glycolysis of polyethylene terephthalate, one of the key processes in the depolymerization of polyethylene terephthalate. The effect of the support size on the catalytic activity was studied in terms of monomer yield, and the monomer concentration was analyzed via high-performance liquid chromatography (HPLC). The morphologies and surface properties of the catalysts were characterized using a scanning electron microscope, a transmission electron microscope, and a BET surface area analyzer, while the monomer was characterized via HPLC and nuclear-magnetic-resonance spectroscopy. Both the zinc oxide and cerium oxide deposited on a smaller support showed better distribution and less aggregation. The high specific surface area of the smaller support catalysts provided a large number of active sites. The highest monomer yield was obtained with a catalyst of 60-nm silica support.

Toxicity profiling of water contextual zinc oxide, silver, and titanium dioxide nanoparticles in human oral and gastrointestinal cell systems.

PubMed

Giovanni, Marcella; Tay, Chor Yong; Setyawati, Magdiel Inggrid; Xie, Jianping; Ong, Choon Nam; Fan, Rongli; Yue, Junqi; Zhang, Lifeng; Leong, David Tai

2015-12-01

Engineered nanoparticles (ENPs) are increasingly detected in water supply due to environmental release of ENPs as the by-products contained within the effluent of domestic and industrial run-off. The partial recycling of water laden with ENPs, albeit at ultra-low concentrations, may pose an uncharacterized threat to human health. In this study, we investigated the toxicity of three prevalent ENPs: zinc oxide, silver, and titanium dioxide over a wide range of concentrations that encompasses drinking water-relevant concentrations, to cellular systems representing oral and gastrointestinal tissues. Based on published in silico-predicted water-relevant ENPs concentration range from 100 pg/L to 100 µg/L, we detected no cytotoxicity to all the cellular systems. Significant cytotoxicity due to the NPs set in around 100 mg/L with decreasing extent of toxicity from zinc oxide to silver to titanium dioxide NPs. We also found that noncytotoxic zinc oxide NPs level of 10 mg/L could elevate the intracellular oxidative stress. The threshold concentrations of NPs that induced cytotoxic effect are at least two to five orders of magnitude higher than the permissible concentrations of the respective metals and metal oxides in drinking water. Based on these findings, the current estimated levels of NPs in potable water pose little cytotoxic threat to the human oral and gastrointestinal systems within our experimental boundaries. © 2014 Wiley Periodicals, Inc.

The Type VI Secretion System Engages a Redox-Regulated Dual-Functional Heme Transporter for Zinc Acquisition.

PubMed

Si, Meiru; Wang, Yao; Zhang, Bing; Zhao, Chao; Kang, Yiwen; Bai, Haonan; Wei, Dawei; Zhu, Lingfang; Zhang, Lei; Dong, Tao G; Shen, Xihui

2017-07-25

The type VI secretion system was recently reported to be involved in zinc acquisition, but the underlying mechanism remains unclear. Here, we report that Burkholderia thailandensis T6SS4 is involved in zinc acquisition via secretion of a zinc-scavenging protein, TseZ, that interacts with the outer membrane heme transporter HmuR. We find that HmuR is a redox-regulated dual-functional transporter that transports heme iron under normal conditions but zinc upon sensing extracellular oxidative stress, triggered by formation of an intramolecular disulfide bond. Acting as the first line of defense against oxidative stress, HmuR not only guarantees an immediate response to the changing environment but also provides a fine-tuned mechanism that allows a gradual response to perceived stress. The T6SS/HmuR-mediated active zinc transport system is also involved in bacterial virulence and contact-independent bacterial competition. We describe a sophisticated bacterial zinc acquisition mechanism affording insights into the role of metal ion transport systems. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Synthesis and dielectric properties of zinc oxide nanoparticles using a biotemplate

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

P, Sharmila P, E-mail: sharmilavishram@gmail.com; Tharayil, Nisha J., E-mail: nishajohntharayil@gmail.com

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 bothmore » AC and DC conductivity are studied and activation energy calculated.« less

Zinc transporter 7 deficiency affects lipid synthesis in adipocytes by inhibiting insulin-dependent Akt activity and glucose uptake

USDA-ARS?s Scientific Manuscript database

Mice deficient for zinc transporter 7 (Znt7) are mildly zinc deficient, accompanied with low body weight gain and body fat accumulation. To investigate the underlying mechanism of Znt7 deficiency in body adiposity, we investigated fatty acid composition and insulin sensitivity in visceral (epididyma...

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.

Requirement of Zinc Transporter SLC39A7/ZIP7 for Dermal Development to Fine-Tune Endoplasmic Reticulum Function by Regulating Protein Disulfide Isomerase.

PubMed

Bin, Bum-Ho; Bhin, Jinhyuk; Seo, Juyeon; Kim, Se-Young; Lee, Eunyoung; Park, Kyuhee; Choi, Dong-Hwa; Takagishi, Teruhisa; Hara, Takafumi; Hwang, Daehee; Koseki, Haruhiko; Asada, Yoshinobu; Shimoda, Shinji; Mishima, Kenji; Fukada, Toshiyuki

2017-08-01

Skin is the first area that manifests zinc deficiency. However, the molecular mechanisms by which zinc homeostasis affects skin development remain largely unknown. Here, we show that zinc-regulation transporter-/iron-regulation transporter-like protein 7 (ZIP7) localized to the endoplasmic reticulum plays critical roles in connective tissue development. Mice lacking the Slc39a7/Zip7 gene in collagen 1-expressing tissue exhibited dermal dysplasia. Ablation of ZIP7 in mesenchymal stem cells inhibited cell proliferation thereby preventing proper dermis formation, indicating that ZIP7 is required for dermal development. We also found that mesenchymal stem cells lacking ZIP7 accumulated zinc in the endoplasmic reticulum, which triggered zinc-dependent aggregation and inhibition of protein disulfide isomerase, leading to endoplasmic reticulum dysfunction. These results suggest that ZIP7 is necessary for endoplasmic reticulum function in mesenchymal stem cells and, as such, is essential for dermal development. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Study of zinc-induced changes in lymphocyte membranes using atomic force microscopy, luminescence, and light scattering methods

NASA Astrophysics Data System (ADS)

Filimonenko, D. S.; Khairullina, A. Ya.; Yasinskii, V. M.; Kozlova, N. M.; Zubritskaja, G. P.; Slobozhanina, E. I.

2011-07-01

Changes in the surface structure of lymphocyte membranes exposed to various concentrations of zinc ions are studied. It is found by atomic force microscopy that increasing the concentration of zinc ions leads to a reduction in the correlation length of the autocorrelation function of the roughness profile of a lymphocyte compared to control samples; this may indicate the existence of fine structure in the membrane surface. Fluorescence markers are used to observe a reduction in the microviscosity of the lipids in the outer monolayer of the lipid bilayer after lymphocytes are exposed to Zn ions, as well as the exposure of phosphatidylserine on the surface membrane, and the oxidation of HS-groups of membrane proteins. Calculations of the absorption coefficients of lymphocytes modified with zinc reveal the existence of absorption bands owing to the formation of metal-protein complexes and zinc oxide nanoparticles. These results indicate significant changes in the structural and functional state of lymphocyte membranes exposed to zinc ions.

Preparation and characterization of an anti-inflammatory agent based on a zinc-layered hydroxide-salicylate nanohybrid and its effect on viability of Vero-3 cells

PubMed Central

Ramli, Munirah; Hussein, Mohd Zobir; Yusoff, Khatijah

2013-01-01

A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells. PMID:23345976

Production of zinc pellets

DOEpatents

Cooper, J.F.

1996-11-26

Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.

Production of zinc pellets

DOEpatents

Cooper, John F.

1996-01-01

Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries.

A comparison of corrosion inhibition of magnesium aluminum and zinc aluminum vanadate intercalated layered double hydroxides on magnesium alloys

NASA Astrophysics Data System (ADS)

Guo, Lian; Zhang, Fen; Lu, Jun-Cai; Zeng, Rong-Chang; Li, Shuo-Qi; Song, Liang; Zeng, Jian-Min

2018-04-01

The magnesium aluminum and zinc aluminum layered double hydroxides intercalated with NO3 -(MgAl-NO3-LDH and ZnAl-NO3-LDH) were prepared by the coprecipitation method, and the magnesium aluminum and the zinc aluminum layered double hydroxides intercalated with VO x -(MgAl-VO x -LDH and ZnAl-VO x -LDH) were prepared by the anion-exchange method. Morphologies, microstructures and chemical compositions of LDHs were investigated by SEM, EDS, XRD, FTIR, Raman and TG analyses. The immersion tests were carried to determine the corrosion inhibition properties of MgAl-VO x -LDH and ZnAl-VO x -LDH on AZ31 Mg alloys. The results showed that ZnAl-VO x -LDH possesses the best anion-exchange and inhibition abilities. The influence of treatment parameters on microstructures of LDHs were discussed. Additionally, an inhibition mechanism for ZnAl-VO x -LDH on the AZ31 magnesium alloy was proposed and discussed.

Peroxynitrite induces destruction of the tetrahydrobiopterin and heme in endothelial nitric oxide synthase: transition from reversible to irreversible enzyme inhibition†

PubMed Central

Chen, Weiguo; Druhan, Lawrence J.; Chen, Chun-An; Hemann, Craig; Chen, Yeong-Renn; Berka, Vladimir; Tsai, Ah-Lim; Zweier, Jay L.

2010-01-01

Endothelial nitric oxide synthase (eNOS) is an important regulator of vascular and cardiac function. Peroxynitrite (ONOO−) inactivates eNOS, but questions remain regarding the mechanisms of this process. It has been reported that inactivation is due to oxidation of the eNOS zinc-thiolate cluster, rather than the cofactor tetrahydrobiopterin (BH4); however, this remains highly controversial. Therefore, we investigated the mechanisms of ONOO−-induced eNOS dysfunction and their dose-dependence. Exposure of human eNOS to ONOO− resulted in a dose-dependent loss of activity with a marked destabilization of the eNOS dimer. HPLC analysis indicated that both free and eNOS-bound BH4 were oxidized during exposure to ONOO−; however, full oxidation of protein bound biopterin required higher ONOO− levels. Additionally, ONOO− triggered changes in UV/Visible spectrum and heme content of the enzyme. Pre-incubation of eNOS with BH4 decreased dimer destabilization and heme alteration. Addition of BH4 to the ONOO−-destabilized eNOS dimer only partially rescued enzyme function. In contrast to ONOO− treatment, incubation with the zinc chelator TPEN with removal of enzyme-bound zinc did not change the eNOS activity or stability of the SDS-resistant eNOS dimer, demonstrating that the dimer stabilization induced by BH4 does not require zinc occupancy of the zinc-thiolate cluster. While ONOO− treatment was observed to induce loss of Zn-binding this can not account for the loss of enzyme activity. Therefore, ONOO−-induced eNOS inactivation is primarily due to oxidation of BH4 and irreversible destruction of the heme/heme-center. PMID:20184376

Antibacterial chitosan/silk sericin 3D porous scaffolds as a wound dressing material.

PubMed

Karahaliloglu, Zeynep; Kilicay, Ebru; Denkbas, Emir Baki

2017-09-01

Antimicrobial mixed dressings have traditionally been used to minimize bacterial infection of burns and other wounds. This study presents the advancement of biocompatible chitosan/silk sericin (CHT/SS) scaffolds combined with lauric acid (LA) and zinc oxide nanoparticles (nZnO) for the successful wound dressing applications. Antibacterial assay results showed that the diameters of the inhibition zone increased from 2 ± 0.4 to 7 ± 0.1 mm for Escherichia coli, as well as from 2.5 ± 0.2 to 6 ± 0.4 mm for Staphylococcus aureus while CHTS/SS/100nZnO compared to CHT/SS/0.01LA. The results not only showed excellent inhibition against Gram-positive and Gram-negative bacterial growth but also revealed improved proliferation and extended viability for HaCaT cells.

Sol-Gel Zinc Oxide Humidity Sensors Integrated with a Ring Oscillator Circuit On-a-Chip

PubMed Central

Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

2014-01-01

The study develops an integrated humidity microsensor fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated humidity sensor consists of a humidity sensor and a ring oscillator circuit on-a-chip. The humidity sensor is composed of a sensitive film and branch interdigitated electrodes. The sensitive film is zinc oxide prepared by sol-gel method. After completion of the CMOS process, the sensor requires a post-process to remove the sacrificial oxide layer and to coat the zinc oxide film on the interdigitated electrodes. The capacitance of the sensor changes when the sensitive film adsorbs water vapor. The circuit is used to convert the capacitance of the humidity sensor into the oscillation frequency output. Experimental results show that the output frequency of the sensor changes from 84.3 to 73.4 MHz at 30 °C as the humidity increases 40 to 90 %RH. PMID:25353984

Dual-step synthesis of 3-dimensional niobium oxide - Zinc oxide

NASA Astrophysics Data System (ADS)

Rani, Rozina Abdul; Zoolfakar, Ahmad Sabirin; Rusop, M.

2018-05-01

A facile fabrication process for constructing 3-dimensional (3D) structure of Niobium oxide - Zinc oxide (Nb2O5-ZnO) consisting of branched ZnO microrods on top of nanoporous Nb2O5 films was developed based on dual-step synthesis approach. The preliminary procedure was anodization of sputtered niobium metal on Fluorine doped Tin Oxide (FTO) to produce nanoporous Nb2O5, and continued with the growth of branched microrods of ZnO by hydrothermal process. This approach offers insight knowledge on the development of novel 3D metal oxide films via dual-step synthesis process, which might potentially use for multi-functional applications ranging from sensing to photoconversion.

Role of manganese dioxide in the recovery of oxide-sulphide zinc ore.

PubMed

Yang, Kun; Zhang, Libo; Zhu, Xingcai; Peng, Jinhui; Li, Shiwei; Ma, Aiyuan; Li, Haoyu; Zhu, Fei

2018-02-05

In this article, the role of MnO 2 in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO 2 during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO 2 will produce an aggregation of ZnMn 2 O 4 , a valuable energy material, while roasting on its own, results in generating undesirable Zn 2 SiO 4 , the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO 2 , which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO 2 effectively avoids, thus MnO 2 deems as a potential additive in the recovery of oxide-sulphide zinc ore. Copyright © 2017. Published by Elsevier B.V.

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

PubMed

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

2014-03-01

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

Effects of Sodium Citrate on the Ammonium Sulfate Recycled Leaching of Low-Grade Zinc Oxide Ores

NASA Astrophysics Data System (ADS)

Yang, Kun; Li, Shi-wei; Zhang, Li-bo; Peng, Jin-hui; Ma, Ai-yuan; Wang, Bao-bao

2016-03-01

The effects of sodium citrate on ammonium sulfate recycled leaching of low-grade zinc oxide ores were studied. By applying various kinds of detection and analysis techniques such as chemical composition analysis, chemical phase method, scanning electron microscopy and energy dispersive spectrum (SEM/EDS), X-ray diffraction (XRD) and Fourier-transforming infrared spectrum (FT-IR), zinc raw ore, its leaching slag and the functional mechanism of sodium citrate were investigated. Based on a comprehensive analysis, it can be concluded that in contrast to hemimorphite (Zn4Si2O7(OH)2 · H2O), amorphous smithsonite (ZnCO3) and zinc silicate (Zn2SiO4) prove to be refractory phases under ammonium sulfate leaching, while sodium citrate has a better chelating action with the refractory phases, resulting in a higher zinc leaching rate. Under conditions of [NH3]/[NH3]T molar ratio being 0.5, [NH3]T being 7.5 mol/L, [Na3C6H5O7] being 0.2 mol/L, S/L ratio being 1:5, temperature being 303 K, holding time being 1 h in each of the two stages, and stirring rate being 300 rpm, the leaching rate of zinc reached 93.4%. In this article, sulfate ammonium recycled technology also reveals its unique advantage in processing low-grade zinc oxide ores accompanied by high silicon and high alkaline gangue.

Supported versus colloidal zinc oxide for advanced oxidation processes

NASA Astrophysics Data System (ADS)

Laxman, Karthik; Al Rashdi, Manal; Al Sabahi, Jamal; Al Abri, Mohammed; Dutta, Joydeep

2017-07-01

Photocatalysis is a green technology which typically utilizes either supported or colloidal catalysts for the mineralization of aqueous organic contaminants. Catalyst surface area and surface energy are the primary factors determining its efficiency, but correlation between the two is still unclear. This work explores their relation and hierarchy in a photocatalytic process involving both supported and colloidal catalysts. In order to do this the active surface areas of supported zinc oxide nanorods (ZnO NR's) and colloidal zinc oxide nanoparticles (having different surface energies) were equalized and their phenol oxidation mechanism and capacity was analyzed. It was observed that while surface energy had subtle effects on the oxidation rate of the catalysts, the degradation efficiency was primarily a function of the surface area; which makes it a better parameter for comparison when studying different catalyst forms of the same material. Thus we build a case for the use of supported catalysts, wherein their catalytic efficiency was tested to be unaltered over several days under both natural and artificial light, suggesting their viability for practical applications.

Mechanisms of LiCoO2 Cathode Degradation by Reaction with HF and Protection by Thin Oxide Coatings.

PubMed

Tebbe, Jonathon L; Holder, Aaron M; Musgrave, Charles B

2015-11-04

Reactions of HF with uncoated and Al and Zn oxide-coated surfaces of LiCoO2 cathodes were studied using density functional theory. Cathode degradation caused by reaction of HF with the hydroxylated (101̅4) LiCoO2 surface is dominated by formation of H2O and a LiF precipitate via a barrierless reaction that is exothermic by 1.53 eV. We present a detailed mechanism where HF reacts at the alumina coating to create a partially fluorinated alumina surface rather than forming AlF3 and H2O and thus alumina films reduce cathode degradation by scavenging HF and avoiding H2O formation. In contrast, we find that HF etches monolayer zinc oxide coatings, which thus fail to prevent capacity fading. However, thicker zinc oxide films mitigate capacity loss by reacting with HF to form a partially fluorinated zinc oxide surface. Metal oxide coatings that react with HF to form hydroxyl groups over H2O, like the alumina monolayer, will significantly reduce cathode degradation.

The beneficial effects of zinc on diabetes-induced kidney damage in murine rodent model of type 1 diabetes mellitus.

PubMed

Yang, Fan; Li, Bing; Dong, Xiaoming; Cui, Wenpeng; Luo, Ping

2017-07-01

Diabetes mellitus is a chronic multi-factorial metabolic disorder resulting from impaired glucose homeostasis. Zinc is a key co-factor for the correct functioning of anti-oxidant enzymes. Zinc deficiency therefore, impairs their synthesis, leading to increased oxidative stress within cells. Zinc deficiency occurs commonly in diabetic patients. The aim of this study is to investigate the effects of varying concentrations of zinc on diabetic nephropathy (DN) and the underlying mechanisms involved. FVB male mice aged 8 weeks were injected intraperitoneally with multiple low-dose streptozotocin at a concentration of 50mg/kg body weight daily for 5 days. Diabetic and age-matched control mice were treated with special diets supplemented with zinc at varying concentrations (0.85mg/kg, 30mg/kg, 150mg/kg) for 3 months. The mice were fed with zinc diets to mimic the process of oral administration of zinc in human. Zinc deficiency to some extent aggravated the damage of diabetic kidney. Feeding with normal (30mg/kg zinc/kg diet) and especially high (150mg/kg zinc/kg diet) concentration zinc could protect the kidney against diabetes-induced damage. The beneficial effects of zinc on DN are achieved most likely due to the upregulation of Nrf2 and its downstream factors NQO1, SOD1, SOD2. Zinc upregulated the expression of Akt phosphorylation and GSK-3β phosphorylation, resulting in a reduction in Fyn nuclear translocation and export of Nrf2 to the cytosol. Thus, regular monitoring and maintaining of adequate levels of zinc are recommended in diabetic individuals in order to delay the development of DN. Copyright © 2017 Elsevier GmbH. All rights reserved.

Hydrothermal Growth of ZnO Nanowires on UV-Nanoimprinted Polymer Structures.

PubMed

Park, Sooyeon; Moore, Sean A; Lee, Jaejong; Song, In-Hyouk; Farshchian, Bahador; Kim, Namwon

2018-05-01

Integration of zinc oxide (ZnO) nanowires on miniaturized polymer structures can broaden its application in multi-functional polymer devices by taking advantages of unique physical properties of ZnO nanowires and recent development of polymer microstructures in analytical systems. In this paper, we demonstrate the hydrothermal growth of ZnO nanowires on polymer microstructures fabricated by UV nanoimprinting lithography (NIL) using a polyurethane acrylate (PUA). Since PUA is a siloxane-urethane-acrylate compound containing the alpha-hydroxyl ketone, UV-cured PUA include carboxyl groups, which inhibit and suppress the nucleation and growth of ZnO nanowires on polymer structures. The presence of carboxyl groups in UV-cured PUA was substantiated by Fourier transform infrared spectroscopy (FTIR), and a Ag thin film was deposited on the nanoimprinted polymer structures to limit their inhibitive influence on the growth of ZnO nanowires. Furthermore, the naturally oxidized Ag layer (Ag2O) reduced crystalline lattice mismatches at the interface between ZnO-Ag during the seed annealing process. The ZnO nanowires grown on the Ag-deposited PUA microstructures were found to have comparable morphological characteristics with ZnO nanowires grown on a Si wafer.

The effect of polymers onto the size of zinc layered hydroxide salt and its calcined product

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir bin; Ghotbi, Mohammad Yeganeh; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

2009-02-01

Zinc hydroxide nitrate, a brucite-like layered material was synthesized using pH control method. Poly(vinyl alcohol) and poly(ethylene glycol) were used at various percentages as size decreasing agents during the synthesis of zinc hydroxide nitrate. SEM and PXRD showed the decrease of size and thickness of the resultant zinc hydroxide nitrates. TG and surface area data confirmed the decrease of the particle sizes, too. When zinc hydroxide nitrates were heat treated at 500 °C, the physical properties of nano zinc oxides obtained depended on the parent material, zinc hydroxide nitrate.

Zinc

USDA-ARS?s Scientific Manuscript database

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 ...

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.

Application of Developed APCVD Transparent Conducting Oxides and Undercoat Technologies for Economical OLED Lighting

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

Silverman, Gary S.; Bluhm, Martin; Coffey, James

2011-01-02

Economics is a key factor for application of organic light emitting diodes (OLED) in general lighting relative to OLED flat panel displays that can handle high cost materials such as indium tin oxide (ITO) or Indium zinc oxide (IZO) as the transparent conducting oxide (TCO) on display glass. However, for OLED lighting to penetrate into general illumination, economics and sustainable materials are critical. The issues with ITO have been documented at the DOE SSL R&D and Manufacturing workshops for the last 5 years and the issue is being exaserbated by export controls from China (one of the major sources ofmore » elemental indium). Therefore, ITO is not sustainable because of the fluctuating costs and the United States (US) dependency on other nations such as China. Numerous alternatives to ITO/IZO are being evaluated such as Ag nanoparticles/nanowires, carbon nanotubes, graphene, and other metal oxides. Of these other metal oxides, doped zinc oxide has attracted a lot of attention over the last 10 years. The volume of zinc mined is a factor of 80,000 greater than indium and the US has significant volumes of zinc mined domestically, resulting in the ability for the US to be self-sufficient for this element that can be used in optoelectonic applications. The costs of elemental zinc is over 2 orders of magnitude less than indium, reflecting the relative abundance and availablility of the elements. Arkema Inc. and an international primary glass manufacturing company, which is located in the United States, have developed doped zinc oxide technology for solar control windows. The genesis of this DOE SSL project was to determine if doped zinc oxide technology can be taken from the commodity based window market and translate the technology to OLED lighting. Thus, Arkema Inc. sought out experts, Philips Lighting, Pacific Northwest National Laboratories (PNNL) and National Renewable Research Laboratories (NREL), in OLED devices and brought them into the project. This project had a clear focus on economics and the work plan focused both on doped ZnO process and OLED device structure that would be consistent with the new TCO. The team successfully made 6 inch OLEDs with a serial construction. More process development is required to optimize commercial OLED structures. Feasibility was demonstrated on two different light extraction technologies: 1/4 lambda refractive index matching and high-low-high band pass filter. Process development was also completed on the key precursors for the TCO, which are ready for pilot-plant scale-up. Subsequently, Arkema has developed a cost of ownership model that is consistent with DOE SSL R&D Manufacturing targets as outlined in the DOE SSL R&D Manufacturing 2010 report. The overall outcome of this project was the demonstration that doped zinc oxide can be used for OLED devices without a drop-off in performance while gaining the economic and sustainable benefits of a more readily available TCO. The broad impact of this project, is the facilitation of OLED lighting market penetration into general illumination, resulting in significant energy savings, decreased greenhouse emissions, with no environmental impact issues such as mercury found in Fluorescent technology.« less

Inflammatory stimuli induce inhibitory S-nitrosylation of the deacetylase SIRT1 to increase acetylation and activation of p53 and p65.

PubMed

Shinozaki, Shohei; Chang, Kyungho; Sakai, Michihiro; Shimizu, Nobuyuki; Yamada, Marina; Tanaka, Tomokazu; Nakazawa, Harumasa; Ichinose, Fumito; Yamada, Yoshitsugu; Ishigami, Akihito; Ito, Hideki; Ouchi, Yasuyoshi; Starr, Marlene E; Saito, Hiroshi; Shimokado, Kentaro; Stamler, Jonathan S; Kaneki, Masao

2014-11-11

Inflammation increases the abundance of inducible nitric oxide synthase (iNOS), leading to enhanced production of nitric oxide (NO), which can modify proteins by S-nitrosylation. Enhanced NO production increases the activities of the transcription factors p53 and nuclear factor κB (NF-κB) in several models of disease-associated inflammation. S-nitrosylation inhibits the activity of the protein deacetylase SIRT1. SIRT1 limits apoptosis and inflammation by deacetylating p53 and p65 (also known as RelA), a subunit of NF-κB. We showed in multiple cultured mammalian cell lines that NO donors or inflammatory stimuli induced S-nitrosylation of SIRT1 within CXXC motifs, which inhibited SIRT1 by disrupting its ability to bind zinc. Inhibition of SIRT1 reduced deacetylation and promoted activation of p53 and p65, leading to apoptosis and increased expression of proinflammatory genes. In rodent models of systemic inflammation, Parkinson's disease, or aging-related muscular atrophy, S-nitrosylation of SIRT1 correlated with increased acetylation of p53 and p65 and activation of p53 and NF-κB target genes, suggesting that S-nitrosylation of SIRT1 may represent a proinflammatory switch common to many diseases and aging. Copyright © 2014, American Association for the Advancement of Science.

High Performance and Highly Reliable ZnO Thin Film Transistor Fabricated by Atomic Layer Deposition for Next Generation Displays

DTIC Science & Technology

2011-08-19

zinc oxide ( ZnO ) thin film as an active channel layer in TFT has become of great interest owing to their specific...630-0192 Japan Phone: +81-743-72-6060 Fax: +81-743-72-6069 E-mail: uraoka@ms.naist.jp Keywords: zinc oxide , thin film transistors , atomic layer...deposition Symposium topic: Transparent Semiconductors Oxides [Abstract] In this study, we fabricated TFTs using ZnO thin film as the

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.

Hybrid Co-deposition of Mixed-Valent Molybdenum-Germanium Oxides (MoxGeyOz): A Route to Tunable Optical Transmission (Postprint)

DTIC Science & Technology

2015-08-05

to increased doping levels in indirect semiconductors [84]. The slope, and magnitude of the transmission curves continue to decrease alongside UL...periodically aluminium- doped zinc oxide thin films, Thin Solid Films 519 (2011) 2280–2286. [2] T. Minami, H. Nanto, S. Takata, Highly conductive and...transparent aluminum doped zinc oxide thin films prepared by RF magnetron sputtering, Jpn. J. Appl. Phys. 23 (1984) L280. [3] T. Minami, Present status of

Simple biosynthesis of zinc oxide nanoparticles using nature's source, and it's in vitro bio-activity

NASA Astrophysics Data System (ADS)

Zare, Elham; Pourseyedi, Shahram; Khatami, Mehrdad; Darezereshki, Esmaeel

2017-10-01

Nanoparticles with antimicrobial activity, especially as a new class of biomedical materials for use in increasing the level of public health in daily life have emerged. In this study, green synthesis of zinc oxide) ZnO(nanoparticles was studied by Cuminum cyminum (cumin) as novel natural source and zinc nitrate [Zn(NO3)2] as Zn2+ source. The results showed that parameters such as concentration, time, temperature and pH have a direct impact on the synthesis of zinc nanoparticles and change in any of the factors causing the change in the process of synthesis. The properties of synthesized nanoparticles were examined by UV-visible Spectrophotometer, X-ray diffraction spectroscopy and transmission electron microscopy (TEM). The UV-visible spectroscopy presented the absorption peak in the range of 370 nm. Transmission electron microscopy images of synthesized nanoparticles are mainly spherical or oval with an average size of about 7 nm. The effect of antimicrobial nanoparticles calculated using disk diffusion method and broth MIC and MBC in different strains of bacteria, which showed that gram positive and negative were sensitive to zinc oxide nanoparticles. The sensitivity of gram-negative bacteria was more.

Topographic, optical and chemical properties of zinc particle coatings deposited by means of atmospheric pressure plasma

NASA Astrophysics Data System (ADS)

Wallenhorst, L. M.; Loewenthal, L.; Avramidis, G.; Gerhard, C.; Militz, H.; Ohms, G.; Viöl, W.

2017-07-01

In this research, topographic, optical and chemical properties of zinc oxide layers deposited by a cold plasma-spray process were measured. Here, zinc micro particles were fed to the afterglow of a plasma spark discharge whereas the substrates were placed in a quite cold zone of the effluent plasma jet. In this vein, almost closed layers were realised on different samples. As ascertained by laser scanning and atomic force microscopic measurements the particle size of the basic layer is in the nanometre scale. Additionally, larger particles and agglomerates were found on its top. The results indicate a partial plasma-induced diminishment of the initial particles, most probably due to melting or vaporisation. It is further shown that the plasma gives rise to an increased oxidation of such particles as confirmed by X-ray photoelectron spectroscopy. Quantitative analysis of the resulting mixed layer was performed. It is shown that the deposited layers consist of zinc oxide and elemental zinc in approximately equal shares. In addition, the layer's band gap energy was determined by spectroscopic analysis. Here, considerable UV blocking properties of the deposited layers were observed. Possible underlying effects as well as potential applications are presented.

Effect of different processes and Ti/Zn molar ratios on the structure, morphology, and enhanced photoelectrochemical and photocatalytic performance of Ti3+ self-doped titanium-zinc hybrid oxides

NASA Astrophysics Data System (ADS)

Fu, Rongrong; Wang, Qingyao; Gao, Shanmin; Wang, Zeyan; Huang, Baibiao; Dai, Ying; Lu, Jun

2015-07-01

Ti3+ self-doped titanium-zinc hybrid oxides with different phase compositions and morphologies were successfully synthesized using Zn powder as the reductant and Zn source by a chemical-reduction precipitation method with subsequent thermal treatment. The fabricated Ti3+ self-doped TiO2(A)/TiO2(R), TiO2(A)/TiO2(R)/ZnTiO3, and TiO2(A)/ZnO heterojunctions were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The effects of various Ti/Zn molar ratios and preparation processes on the structural, morphological, optical, photocurrent and photocatalytic properties of the resultant samples were investigated systematically. Results reveal that Ti3+ self-doping enhances the photoabsorption capability of titanium-zinc hybrid oxides in the visible-light region. Moreover, different processes and Ti/Zn molar ratios play great influences on the structure, morphology, optical, photocurrent and photocatalytic properties of the final products. Ti3+ self-doped titanium-zinc hybrid oxides exhibit excellent photocurrent and photocatalytic activity than pure TiO2 and ZnTiO3 under visible-light irradiation (λ ≥ 400 nm). The most active Ti3+ self-doped titanium-zinc hybrid oxides photoanode presents significantly improved water splitting performance. The synergistic effect between the Ti3+ self-doped and heterojunctions is responsible for the enhanced performance of these materials.

Nitric Oxide Is Associated with Long-Term Zinc Tolerance in Solanum nigrum1[W

PubMed Central

Xu, Jin; Yin, Hengxia; Li, Yulong; Liu, Xiaojing

2010-01-01

Nitric oxide (NO) has been identified as a signal molecule that interplays with reactive oxygen species in response to heavy metal stresses. Roles of NO in regulating cadmium toxicity and iron deficiency have been proposed; however, the function of NO in zinc (Zn) tolerance in plants remains unclear. Here, we investigated NO accumulation and its role in plant Zn tolerance. Zn-induced NO production promoted an increase in reactive oxygen species accumulation in Solanum nigrum roots by modulating the expression and activity of antioxidative enzymes. Subsequently, programmed cell death (PCD) was observed in primary root tips. Inhibiting NO accumulation by 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (a specific NO scavenger) or NG-nitro-l-arginine-methyl ester (a NO synthase inhibitor) prevented the increase of superoxide radical and hydrogen peroxide as well as the subsequent cell death in the root tips, supporting the role of NO in Zn-induced PCD in the root tips. Zn-induced NO production affected the length of primary roots, the number of lateral roots, and root hair growth and thereby modulated root system architecture and activity. Investigation of metal contents in Zn-treated roots suggests that NO is required for metal (especially iron) uptake and homeostasis in plants exposed to excess Zn. Taken together, our results indicate that NO production and the subsequent PCD in root tips exposed to excess Zn are favorable for the S. nigrum seedling response to long-term Zn toxicity by modulating root system architecture and subsequent adaptation to Zn stress. PMID:20855519

SYNTHESIS, REACTIVITY, AND CATALYTIC BEHAVIOR OF IRON/ZINC-CONTAINING SPECIES INVOLVED IN OXIDATION OF HYDROCARBONS UNDER GIF-TYPE CONDITIONS. (R823377)

EPA Science Inventory

The present study explores the nature and reactivity of iron- and zinc-containing species
generated in hydrocarbon-oxidizing Gif(IV)-type solutions Fe catalyst/Zn/O-2 in pyridine/acetic acid
(10:1 v/v). The ultimate goal of this investigation is to unravel the role of metal...

Effect of Nitrogen Oxides on Elemental Mercury Removal by Nanosized Mineral Sulfide.

PubMed

Li, Hailong; Zhu, Lei; Wang, Jun; Li, Liqing; Lee, Po-Heng; Feng, Yong; Shih, Kaimin

2017-08-01

Because of its large surface area, nanosized zinc sulfide (Nano-ZnS) has been demonstrated in a previous study to be efficient for removal of elemental mercury (Hg 0 ) from coal combustion flue gas. The excellent mercury adsorption performance of Nano-ZnS was found to be insusceptible to water vapor, sulfur dioxide, and hydrogen chloride. However, nitrogen oxides (NO X ) apparently inhibited mercury removal by Nano-ZnS; this finding was unlike those of many studies on the promotional effect of NO X on Hg 0 removal by other sorbents. The negative effect of NO X on Hg 0 adsorption over Nano-ZnS was systematically investigated in this study. Two mechanisms were identified as primarily responsible for the inhibitive effect of NO X on Hg 0 adsorption over Nano-ZnS: (1) active sulfur sites on Nano-ZnS were oxidized to inactive sulfate by NO X ; and (2) the chemisorbed mercury, i.e., HgS, was reduced to Hg 0 by NO X . This new insight into the role of NO X in Hg 0 adsorption over Nano-ZnS can help to optimize operating conditions, maximize Hg 0 adsorption, and facilitate the application of Nano-ZnS as a superior alternative to activated carbon for Hg 0 removal using existing particulate matter control devices in power plants.

Flexible and High-Performance Amorphous Indium Zinc Oxide Thin-Film Transistor Using Low-Temperature Atomic Layer Deposition.

PubMed

Sheng, Jiazhen; Lee, Hwan-Jae; Oh, Saeroonter; Park, Jin-Seong

2016-12-14

Amorphous indium zinc oxide (IZO) thin films were deposited at different temperatures, by atomic layer deposition (ALD) using [1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]indium (INCA-1) as the indium precursor, diethlzinc (DEZ) as the zinc precursor, and hydrogen peroxide (H 2 O 2 ) as the reactant. The ALD process of IZO deposition was carried by repeated supercycles, including one cycle of indium oxide (In 2 O 3 ) and one cycle of zinc oxide (ZnO). The IZO growth rate deviates from the sum of the respective In 2 O 3 and ZnO growth rates at ALD growth temperatures of 150, 175, and 200 °C. We propose growth temperature-dependent surface reactions during the In 2 O 3 cycle that correspond with the growth-rate results. Thin-film transistors (TFTs) were fabricated with the ALD-grown IZO thin films as the active layer. The amorphous IZO TFTs exhibited high mobility of 42.1 cm 2 V -1 s -1 and good positive bias temperature stress stability. Finally, flexible IZO TFT was successfully fabricated on a polyimide substrate without performance degradation, showing the great potential of ALD-grown TFTs for flexible display applications.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment.

PubMed

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-22

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment

PubMed Central

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-01

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment. PMID:28809311

Metalorganic chemical vapor deposition and characterization of ZnO materials

NASA Astrophysics Data System (ADS)

Sun, Shangzu; Tompa, Gary S.; Hoerman, Brent; Look, David C.; Claflin, Bruce B.; Rice, Catherine E.; Masaun, Puneet

2006-04-01

Zinc oxide is attracting growing interest for potential applications in electronics, optoelectronics, photonics, and chemical and biochemical sensing, among other applications. We report herein our efforts in the growth and characterization of p- and n-type ZnO materials by metalorganic chemical vapor deposition (MOCVD), focusing on recent nitrogen-doped films grown using diethyl zinc as the zinc precursor and nitric oxide (NO) as the dopant. Characterization results, including resistivity, Hall measurements, photoluminescence, and SIMS, are reported and discussed. Electrical behavior was observed to be dependent on illumination, atmosphere, and heat treatment, especially for p-type material.

Synthesis, characterization and photocatalytic activity of magnetically separable hexagonal Ni/ZnO nanostructure

NASA Astrophysics Data System (ADS)

Senapati, Samarpita; Srivastava, Suneel K.; Singh, Shiv B.

2012-09-01

The hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure photocatalyst has successfully been prepared by the reduction of nickel chloride hexahydrate using hydrazine hydrate through the solvothermal process at 140 °C followed by surface modification of the product by the reflux method at 110 °C for 1 h. The X-ray diffraction (XRD) pattern showed that the `as prepared' sample consists of face centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused.The hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure photocatalyst has successfully been prepared by the reduction of nickel chloride hexahydrate using hydrazine hydrate through the solvothermal process at 140 °C followed by surface modification of the product by the reflux method at 110 °C for 1 h. The X-ray diffraction (XRD) pattern showed that the `as prepared' sample consists of face centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused. Electronic supplementary information (ESI) available: Fig. S1 Ni/ZnO hybrid nanostructure prepared using (a) 0.195 and (b) 0.25 M [Zn2+] at 90 °C Fig. S2 FTIR spectra of nickel nanoparticles prepared at 140 °C (a), and Ni/ZnO hybrid nanostructure prepared using (b) 0.063, (c) 0.125, (d) 0.195 and (e) 0.25 M [Zn2+]; Fig. S3 Raman spectra of Ni/ZnO nanostructure prepared using (a) 0.063, (b) 0.125, (c) 0.195 and (d) 0.25 M [Zn2+]; Fig. S4 Room temperature PL spectra of (a) ZnO and (b) Ni/ZnO nanostructure prepared using 0.25 M [Zn2+]. See DOI: 10.1039/c2nr31831h