196,185 research outputs found

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

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    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

    The reactions pertaining to zinc-silver and cadmium-silver batteries First quarterly report

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    Zinc precipitates and thermogravimetric studies of silver oxide for zinc-silver and cadmium-zinc batterie

    Aluminium or copper substrate panel for selective absorption of solar energy

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    A method for making panels which selectively absorb solar energy is disclosed. The panels are comprised of an aluminum substrate, a layer of zinc thereon, a layer of nickel over the zinc layer and an outer layer of solar energy absorbing nickel oxide or a copper substrate with a layer of nickel thereon and a layer of solar energy absorbing nickel oxide distal from the copper substrate

    Stable White Coatings

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    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)

    Improved separators for silver oxide-zinc and silver oxide-cadmium cells for spacecraft application First quarterly progress report, 10 Nov. 1964 - 9 Feb. 1965

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    Silver oxide diffusion tests on separator membranes for use in silver oxide-cadmium and silver oxide-zinc electrochemical cell

    Study of the zinc-silver oxide battery system Quarterly report, Oct. 1969

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    Silver oxide electrodes and transport parameters in zinc-silver oxide battery syste

    The behavior of several white pigments as determined by in situ reflectance measurements of irradiated specimens

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    Reflectance measurements of irradiated specimens of zinc oxide and zinc orthotitanate white pigment material

    Zinc oxide nanoparticles as selective killers of proliferating cells

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    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

    Improved separators for silver oxide-zinc and silver oxide-cadmium cells for spacecraft application Final report, Nov. 10, 1964 - Nov. 10, 1965

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    Improved separators for silver oxide-zinc and silver oxide-cadmium cells for spacecraft applicatio

    Improved separators for silver oxide-zinc and silver oxide-cadmium cells for spacecraft application Second quarterly progress report, 10 Feb. - 9 May 1965

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    Separators for silver oxide-zinc and silver oxide- cadmium cells for spacecraft applicatio
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