• YAKHAK HOEJI
• /
• v.57 no.4
• /
• pp.282-288
• /
• 2013

Zinc oxide nanoparticles (ZnONPs) are widely used in a variety of products and cosmetic products including paper, paints, plastics and sunscreen. However, information on the safety of ZnONPs are not enough and many publications suggest possible toxic effects on environmental and human health. Furthermore, physico-chemical characteristics of nanoparticles makes it hard to test toxicity using the test guidelines of chemicals adopted by regulatory bodies. In this study, stability of ZnONPs was investigated using different types of isotonic solution, which is important in the toxicity study of intravenous route. Precipitation, aggregation, size, zeta potential and morphology of ZnONPs were evaluated with different times and concentrations. Precipitation of ZnONPs were observed in ionic isotonic solution including phosphate-buffered saline, Kreb's-Ringer solution, physiological salt solution and cell culture media of DMEM (Dulbecco's Modified Eagle's Medium) with 10% fetal bovine serum. On the other hand, they were stable without precipitation in non-ionic isotonic solution such as 5% glucose and 2% glycerol, respectively, which are biocompatible for intravenous injection. The average size of ZnONPs in 5% glucose and 2% glycerol was stably maintained, which is less than 30 nm and very similar as that in water dispersion of ZnONPs, provided by the manufacturer. The stability was maintained during the experimental period of 5 days and diluted state up to 15,000 ppm. These data suggest that 5% glucose and 2% glycerol solution can be used for the vehicles of ZnONPs in the toxicity study of intravenous injection route.

• Molecules and Cells
• /
• v.44 no.5
• /
• pp.335-341
• /
• 2021

Zinc is an essential micronutrient with crucial roles in multiple facets of biological processes. Dysregulated zinc homeostasis impairs overall immune function and resultantly increases susceptibility to infection. Clinically, zinc supplementation is practiced for treatment of several infectious diseases, such as diarrhea and malaria. Recent focus on zinc as a beneficial element for immune system support has resulted in investigation of the immunomodulatory roles of zinc in a variety of immune cells. Besides its classical role as a cofactor that regulates the structural function of thousands of proteins, accumulating evidence suggests that zinc also acts, in a manner similar to calcium, as an ionic regulator of immune responses via participation as an intracellular messenger in signaling pathways. In this review, we focus on the role of zinc as a signaling molecule in major pathways such as those downstream of Toll-like receptors-, T cell receptor-, and cytokine-mediated signal transduction that regulate the activity and function of monocytes/macrophages and T cells, principal players in the innate and adaptive immune systems.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.191-195
• /
• 2003

Zinc acetate has been proposed and used to evaluate ionic zinc as a means to reduce reactor radiation buildup at several nuclear plants. Thermodynamic analysis of the aqueous zinc system using reliable data shows that the stability of the hydrolyzed zinc species increases with pH and temperature. Adsorption kinetics and isotherm studies were carried out to investigate the mixed resin performance of the zinc adsorption. The equilibrium isotherms of the zinc adsorption onto nuclear grade resin indicate that the data correlate well with the Langmuir model and that the adsorption is physical in nature. The maximum capacity according to the Langrnuir model is about 0.6meq/g for an initial zinc concentration of 100ppm at $50^{\circ}C$. The use of natural zinc could result in the generation of a $^{65}Zn$ activity with about $500{\mu}Ci/mL$ of resin after 12 months of operation.

• Preventive Nutrition and Food Science
• /
• v.2 no.3
• /
• pp.219-224
• /
• 1997

The pancreas is an important organ in the maintenance of zine homeostasis. The pancreatic tissue used in this study was obtained from rats fed varying levels of dietary Ca nd phytate followed by intraperitoneal {TEX}${65}^Zn${/TEX} injection. THe objective of this study was to determine the molecular size and distribution of compounds that may represent zinc-binding complexes in pancreatic tissue homogenates. The supernatant of the homogenized pancreatic tissue was separated using a Sephadex G-75 column with Tris buffer at pH 8.1. All subfractions were assayed for zinc, protein and {TEX}${65}^Zn${/TEX} activity. The elution of subfractions from pancreatic tissue homogenates showed a prominent peak corresponding to the high molecular weight protein standard (>66kd). A sall molecular weigth protein (<6.5kd), that was absorbed at 280nm, was also present: prominently in low Ca group, however not much as in high Ca group. These small compounds may combine weakly with zinc in pancreatic tissue an serve as zinc-binding ligands in pancreatic/biliary fluid. In the duodenum, these ligands dissociate zinc into an ionic form which becomes vulnerable to phytate complexation.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.3
• /
• pp.682-684
• /
• 2008

• Applied Microscopy
• /
• v.33 no.2
• /
• pp.145-154
• /
• 2003

The present study was designed to demonstrate ionic zinc in the rat nasal mucosa by means of zinc selenium autometallography ($ZnSe^{AMG}$). Rats were given sodium selenide either intraperitoneally (i.p) or intranasally (i.n). Prior to the i.n. administration the rats were anesthetized with pentobarbital sodium (30 mg/kg, i.p.). A thin plastic tube coupled to a Hamilton syringe was then inserted into the right nostril and $10{\mu}l$ of the solution was instilled. For the i.p. administration non-anesthetized rats were given $100{\mu}l$ of the sodium selenide solution (10 mg/kg). Control rats were instilled with saline. After 2 hrs survival, the rats were anaesthetized and transcardially perfused with 3% glutaraldehyde. The olfactory area was removed and put into same fixative. The nose was then sectioned ($30{\mu}m$) horizontally, autometallography (AMG) was performed according to Danscher et al. (1997). After silver enhancement, fine AMG grains were scattered in the whole length of the olfactory epithelium containing olfactory receptor neurons, sustentacular and basal cells. However, much higher concentration of the AMG grains occupied near the surface and in the basal region of the olfactory epithelium. Both groups of i.p. and i.n. administration showed almost same level in the concentration of the AMG grains. In i.n. group, few AMG grains were also found in olfactory nerves of the lamina propria, suggesting zinc transport into the olfactory bulb via olfactory axons. At the electron microscopic level, the AMG grains were most entirely found in the supporting cells of the olfactory epithelium, and they were mostly localized in lysosome-like organelles. The i.n. group showed various signs of tissue damage of the olfactory mucosa, where dense concentration of AMG grains were localized at crystalloid structures. The present study demonstrated dense population of ionic zinc in the rat olfactory epithelium. zinc may play a role in the olfactory functioin and in the pathogenesis of the neurodegerative disorders affecting nose.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.11
• /
• pp.2025-2028
• /
• 2007

Homogeneous zinc tetrahalide complexes, highly active catalysts for the coupling reactions of alkylene oxide and CO2 produce alkylene carbonates, were heterogenized due to their tendency to decompose produced alkylene carbonates during the distillation process. Heterogenization of homogeneous zinc tetrahalide complexes was achieved by polymerizing 1-alkyl-3-vinylimidazolium zinc tetrahalides. These polymerized zinc tetrahalide catalysts displayed similar activities to their corresponding monomeric analogues for the coupling reactions of carbon dioxide with ethylene oxide (EO) or propylene oxide (PO) to produce ethylene carbonate (EC) or propylene carbonate (PC). TGA studies showed that the polymer-supported zinc tetrahalide catalysts are thermally stable up to 320 oC. The catalyst recycle test showed that the supported catalysts could be reused over six times. After removal of the polymer-supported catalyst through a simple filtration, EC was able to be isolated without decomposition.

• Applied Microscopy
• /
• v.40 no.1
• /
• pp.15-19
• /
• 2010

The present study was designed to demonstrate ionic zinc in the rat DRG by means of zinc selenium autometallography($ZnSe^{AMG}$). Ganglion cells varied in size from 15 to 100 ${\mu}m$. The smaller neurons were strongly stained with AMG, whereas the larger cells were weakly stained. Each large ganglion cell was surrounded by perineuronal satellite cells, showing apparent AMG staining. We demonstrated for the first time the existence of zinc-containing satellite cells in the rodent DRG. Using electron microscopy, fine AMG grains were observed scattered in the somata of the DRG neurons, especially small cells. However, much lower concentrations of the AMG grains occupied in the large cells, and these were mostly localized in lysosome-like organelles. These results indicate that zinc may be involved in sensory transmission in the DRG level.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.1
• /
• pp.35-40
• /
• 2010

A comprehensive comparative investigation of small carbohydrates in laser desorption ionization was performed on supporting materials composed of sodiated 2,5-dihydroxybenzoic acid (DHB), carbon nanotubes, an ionic liquid matrix of DHB-pyridine, a binary matrix of DHB-aminopyrazine, zinc oxide nanoparticles, and gold nanoparticles. The abundance of $[M+Na]^+$ ions, where M is glucose or sucrose, was compared for each supporting material. The highest sensitivity for both glucose and sucrose, with a detection limit of 3 pmol, was observed with carbon nanotubes. Both carbon nanotubes and the ionic liquid matrix exhibited the highest reproducibility.

• Polymer(Korea)
• /
• v.28 no.2
• /
• pp.185-193
• /
• 2004

Elastomeric nanocomposites were prepared by employing zinc dimethacrylate into an acrylonitrile-butadiene rubber, and their network structures, mechanical properties, and fracture morphologies were investigated according to the adding methods and contents of zinc dimethacrylate. The total crosslink density increased with increasing the zinc dimethacrylate level, due to increased ionic bonds. Both the tensile strength and tear strength increased with increasing zinc dimethacrylate loadings, and then decreased after reaching a maximum value. It was found that the tear strength and crack resistance were greatly affected by the mixing method of zinc dimethacrylate. The in-situ nanocomposites, where zinc dimethacrylate particles were formed by the reaction of zinc oxide and methacrylic acid, showed much improved tear strength and crack resistance compared to those of the nanocomposites based on the direct mixing of zinc dimetacrylate powders. This was because of the finer zinc dimethacrylate particles and improved dispersion of the in-situ nanocomposites.