• Nutrition Research and Practice
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• v.5 no.1
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• pp.46-51
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• 2011

To evaluate the effect of feeding methods on growth and zinc nutritional status of infants early in life, we monitored from birth to 36 months in 51 infants who were exclusively fed human milk (HM, n=20), casein-based formula (CBF, n=12), or soy-based formula (SBF, n=19) during the first five months of life. Zinc status was assessed by analyzing serum zinc concentrations and zinc intakes. Zinc contents in HM and formulas were measured. Zinc intake was estimated by weighing infants before and after feeding in the HM group and by collecting formula-intake records in the CBF and SBF groups. After solid foods were introduced, all foods consumed were also included to estimate zinc intake. The growth of infants in all groups was similar to that established for normal Korean infants. Human milk zinc concentrations declined as lactation progressed. Zinc concentrations in all formulas tested in this study were higher than HM and were also higher than those claimed by the manufacturers. During the first twelve months, mean serum zinc concentrations of infants were similar in all groups, although infants in the HM group consistently had the lowest zinc intake among the groups, and the overall zinc intake in infants fed SBF was highest. This finding could be explained by the difference zinc bioavailability of HM and formulas. In conclusion, infants fed HM, CBF or SBF has normal growth up to three years of age, although HM contained the lowest zinc concentration followed by CBF, then SBF.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4627-4634
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• 2013

Chemoprotection refers to the use of specific natural or synthetic chemical agents to suppress or prevent the progression to cancer. The purpose of this study is to assess the protective effect of aspirin, vitamin C or zinc in a dimethyl hydrazine (DMH) colon carcinoma model in rats and to investigate the effect of these supplements on changes associated with colonic zinc status. Rats were randomly divided into three groups, group 1 (aspirin), group 2 (vitamin C) and group 3 (zinc), each being subdivided into two groups and given subcutaneous injection of DMH (30 mg/kg body wt) twice a week for 3 months and sacrificed at 4 months (A-precancer model) and 6 months (B-cancer model). Groups 1, 2, 3 were simultaneously given aspirin, vitamin C, or zinc supplement respectively from the beginning till the end of the study. It was observed that 87.5% of rats co-treated with aspirin or vitamin C showed normal colonic histology, along with a significant decrease in colonic tissue zinc at both time points. Rats co-treated with zinc showed 100% reduction in tumor incidence with no significant change in colonic tissue zinc. Plasma zinc, colonic CuZnSOD (copper-zinc superoxide dismutase) and alkaline phosphatase activity showed no significant changes in all 3 cotreated groups. These results suggest that aspirin, vitamin C or zinc given separately, exert a chemoprotective effect against chemically induced DMH colonic preneoplastic progression and colonic carcinogenesis in rats. The inhibitory effects are associated with maintaining the colonic tissue zinc levels and zinc enzymes at near normal without significant changes.

• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.132-136
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• 2007

Zinc is essential metal and plays a role in a wide variety of physiological and biochemical processes. Prostate gland contains high level of zinc, generally 3-10 folds higher than other organs. Prostatic zinc uptake is resulted from the existence of zinc transporter (ZnT) protein families in membrane. In this study, we investigated the difference of zinc uptake efficiency of zinc-aspartate complex (Zn-Asp) into various organs compared with $ZnSO_4$. We observed that Plasma zinc concentration in both $ZnSO_4$ and Zn-Asp administrated group was increased progressively following administration, and reached a peak level at 2 hr. The increasing pattern of zinc concentration was similar to each groups, however the zinc concentration of Zn-Asp administrated group was higher than that of $ZnSO_4$ administrated group. We found that prostatic zinc level of Zn-Asp administrated group was higher than $ZnSO_4$ administrated group, and was increased approximately $\sim$2.7 fold and $\sim$4.2 fold at 4 and 8 hr after administration. From these observations, we suggest than Zn-Asp has high uptake efficiency of zinc into the prostate gland. Therefore, Zn-Asp is potentially useful treatment of many prostatic diseases.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.352-359
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• 2012

One hundred thirty-four putative Bacillus isolates were recovered from soybean rhizosphere soils of Nimar region to select effective zinc solubilizers for increased assimilation of zinc (Zn) in soybean seeds. These isolates were screened in vitro for zinc-solubilization ability on Tris-minimal agar medium supplemented separately with 0.1% zinc in the form of zinc oxide, zinc phosphate, and zinc carbonate. Of all, 9 isolates and a reference Bacillus cereus ATCC 13061 were characterized and identified as Bacillus species based on Gram-positive reaction, endospore-forming cells, and the presence of iso-$C_{15:0}$ and anteiso-$C_{15:0}$ as predominant fatty acids. On plate assay, two isolates KHBD-6 and KHBAR-1 showed a greater diameter of solubilization halo and colony diameter on all the three zinc compounds. The isolates KHBD-6, KHBAR-1, BDSD-2-2C, and KHTH-4-1 and the reference strain ATCC 13061 had higher soluble zinc concentration in liquid medium supplemented with zinc phosphate and zinc carbonate compounds as compared with the other isolates and uninoculated control. Evaluation under microcosm conditions showed that inoculation of isolates KHBD-6 (57.34 ${\mu}g/g$), KHBAR-1 (55.67 ${\mu}g/g$), and strain ATCC 13061 (53.10 ${\mu}g/g$) significantly increased the Zn concentration in soybean seeds as compared with the other isolates and uninoculated control (47.14 ${\mu}g/g$). This study suggests the occurrence of zinc-solubilizing Bacillus in soils of Nimar region and isolates KHBD-6 and KHBAR-1 were found to be promising zinc solubilizers for increased assimilation of Zn in soybean seeds.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.752-757
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• 2011

The effects of reaction temperature, reactant concentration, pH of solution and mixing order of reactants on the particle shape and size distribution of zinc oxide were investigated in the preparation of zinc oxide from ammonium hydroxide and zinc acetate by the method of aqueous hydrothermal precipitation method, and the photocatalytic ability of zinc oxide synthesized was measured from the degradation of tartrazine under UV irradiation. The average particle size was increased with pH of solution but decreased with zinc acetate concentration and reaction temperature. The optimum condition for the synthesis of minimum sized zinc oxide was pH 11.2, concentration of zinc acetate 0.6 M and reaction temperature $90^{\circ}C$, and its average particle size was 3.133 ${\mu}$m. 97% of tartrazine was degraded by zinc oxide in sixty minutes.

• Nutrition Research and Practice
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• v.17 no.6
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• pp.1211-1224
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• 2023

BACKGROUND/OBJECTIVES: This study aimed to evaluate the food sources of zinc and the usual intake of dietary zinc among Korean toddlers and preschool children. SUBJECTS/METHODS: A total of 2,679 children aged 1-5 years was selected from the 2009-2013 Korea National Health and Nutrition Examination Survey (KNHANES) data. Dietary data collected from a single 24-h recall were used to evaluate the food sources of zinc. To estimate usual zinc intake, the distribution obtained from single 24-h recall data in the total sample was adjusted using the ratio of within-to-between-person variance in zinc intake obtained from 2-day 24-h recall sub-sample data of the 2009 KNHANES. The proportion of children with usual zinc intake below the estimated average requirement (EAR) and above the tolerable upper intake level (UL) was assessed. RESULTS: The main sources of zinc in Korean children were grains, dairy products, and meat. The mean usual intakes of zinc among all individuals, those aged 1-2 yrs, and those aged 3-5 yrs were 5.50, 5.01, and 5.83 mg/d, respectively. In all participants, 1.1% of the children consumed zinc below the EAR, whereas 10.7% exceeded the UL. The proportion of children with excessive zinc intake was 25.6% in the 1-2 yrs age group and 0.6% in the 3-5 yrs age group. CONCLUSIONS: According to the current UL, the risk of excessive zinc intake appears to be high among Korean toddlers. Future studies that monitor the health effects of excessive zinc intake are needed to appropriately guide zinc intake in children.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.7
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• pp.966-969
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• 2001

Some researchers reported that beef marbling was improved by the supplementation of organic zinc to a diet satisfying zinc requirement. We studied the relationship between serum zinc concentration and marbling score or serum adipogenic activity in 40 fattened steers. To determine serum adipogenic activities of the steers, preadipocytes were cultured in medium containing the serum samples during differentiation. Although serum zinc concentration was not related to beef marbling score, it was positively correlated to adipogenic activity. Then, we studied the effect of zinc on adipocyte differentiation. Zinc was added into the medium with the similar methods except the addition of fattened calf serum. The activity of glycerophosphate dehydrogenase, a marker of adipocyte differentiation, was significantly increased by the addition of zinc in culture with or without insulin. These results suggest that zinc possibly improved beef marbling through increasing adipogenic activity during fattening.

• Journal of the Korean institute of surface engineering
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• v.34 no.6
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• pp.537-544
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• 2001

In the present study, tin-zinc alloys were coated on a cold-rolled steel sheet with variations of electrolyte concentration, additives quantity and current density employing the Hull cell and circulation cell simulator. With an addition of additives of 2m1/L, tin-zinc deposits containing 10 to 40 percent Zn revealed a good surface appearance with weak acidic electrolytes. The organic additives suppressed the Sn deposition rate and thus increased the zinc contents in tin-zinc coating layers. The zinc contents in the tin-zinc coating layers depended almost linearly on the concentrations of metal ions of tin and zinc. Temperature of the electrolyte affected the composition tin-zinc coating layer. However, the concentration of complexants revealed little effectiveness. The surface morphology of tin-zinc coating showed dense tin and zinc phases with fine equiaxed grains with the high current density.

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.963-969
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• 1992

This paper describes the feasibility for a direct production of zinc oxalate powders from zinc-loaded D2EHPA solutions combining the purification and the precipitation in one operation unit. This process has the potential as an alternative to conventional method for the synthesis of zinc oxide precursor particles from the hydrometal-lurgical processes. Zinc was extracted into D2EHPA in kerosene and then zinc-loaded D2EHPA solution was emulsified with oxalic acid-HCl solution to precipitate zinc oxalate powder, which was readily calcined to zinc oxide. The precipitation kinetics and yield were sensitive to experimental conditions. The morphology, size and size distribution of the zinc oxalate powders varied with zinc/oxalate ion riatio, temperature, and the presence of SPAN 60, which affected nucleation, growth, and the emulsion characteristics.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.3
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• pp.117-123
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• 2020

Due to high corrosion resistance, Zinc has been widely used in the automobile, shipping or construction industries as a galvanizing material. Zinc is popular as a coating element, but its low mechanical strength impede the expansion of applications as a load-bearing structure. The mechanical strength of Zinc can be increased through zinc based alloy process, but the ductility is significantly reduced. In this study, the mechanical strength and ductility of Zinc-Magnesium alloys with respect to heat treatment hold time was investigated. In order to enhance the mechanical strength of Zinc, a Zinc-Magnesium alloy was fabricated by a melting process. The heat treatment process was performed to improve the ductility of Zinc-Magnesium alloy. The microstructure of the heat-treated alloy specimen was analyzed using SEM. The hardness and compressive strength of the specimen were measured by a micro-hardness tester and a nano-indenter, respectively.