• Journal of Korean Ophthalmic Optics Society
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• v.12 no.1
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• pp.23-33
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• 2007

It has been reported high concentrations of zinc and taurine in ocular tissue, especially the retina-choroid, and the presence of physiological levels of zinc and taurine in these tissues seem essential for their normal function. In addition, several studies have reported temperature as another effector to the visual sensitivity. But, in spite of many studies, there are still remained many questions about their function and correlation in visual adaptation system. The purpose of present study was to clarify these points using electroretinogram(ERG) recording and absorption spectra scanning, before and after zinc and taurine treatments and hypothermic-effect in bullfrog(Rana catesbeiana) which is one of the poikilothermal animal. The optimal zinc concentration used in this study was determined $10^{-4}M$ while the optimal taurine concentration was 10-5 M, and temperature change for hypothermic-effect went through '$25^{\circ}C {\rightarrow}0^{\circ}C{\rightarrow}25^{\circ}C$'. In ERG recording, it is obtained that dark-adapted threshold became elevated and b-wave amplitudes was increased with zinc and taurine treatment and hypothermic-effect. In absorption spectra scanning, there is distinct absorbance increment over the whole spectral range(400~750 nm) after zinc and taurine treatment and hypothermic-effect. Furthermore there are some synergism effects between zinc and taurine as well as between zinc and hypothermic-effect as a result of co-treatment, respectively.

• Journal of Nutrition and Health
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• v.40 no.4
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• pp.385-394
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• 2007

The purpose of this study was to determine the zinc status of preschool children in Ulsan. The study was conducted in 95 children aged 3 to 6 years by investigating the anthropometric indices and assessing the biochemical analysis. The blood was analysed to assess serum zinc and alkaline phosphatase. And a questionnaire for dietary intakes using 24-hr recall method were performed by mothers of 95 subjects. The dietary intakes of children were analysed to determine the prevalence of inadequate and excessive intakes of zinc with Dietary Reference Intakes for Koreans (KDRIs). WHL (Weight-Length Index) and Kaup index were used to define obesity. The overall prevalence of overweight and obese subjects were 14.7% and 6.3% by WHL, were 15.8% and 13.7% by Kaup index. The mean intakes of zinc by children aged 3${\sim}$5y and 6y were 5.5 ${\pm}$ 1.4 mg/d (75.7% RDA) and 6.7 ${\pm}$ 2.0 mg/d, respectively, that was the level exceeding the estimated average requirement (EAR) and the recommended intake (RI) of Korean Dietary Reference Intakes. Less than 1.3% and 7.9% of children had usual zinc intakes below EAR and RI of KDRIs, respectively. The percentages of children with intakes exceeding the tolerable upper intake level (UL) were 2.6%. The zinc nutritional status by biological assay was found that mean serum zinc and alkaline phosphatase (ALP) of total subjects were 64.0 ${\pm}$ 8.4 ${\mu}$g/dl and 72.8 ${\pm}$ 14.9 U/L, there was not a significant difference between boys and girls. The range of serum zinc level was 45${\sim}$89 ${\mu}$g/dl and children with a low serum zinc concentration by several cut-off points were 18.9${\sim}$55.8%, especially. Serum zinc level was positively correlated to the intakes of calorie, calcium, fiber, iron, zinc, zinc/kg and height (p<0.001). Serum ALP was positively correlated height, weight and WLI. The zinc intake of children aiso showed a positive correlation with height and weight. These results indicate that there were significant correlations between the zinc status and growth of preschool children. Preschool children in Ulsan have dietary zinc intakes that exceed the new DRIs. The present level of intake does not seem to pose a health problem, but if zinc intakes with fortified foods and supplements were considered, the amount of zinc consumed by children may become excessive.

• The Korean Journal of Ecology
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• v.9 no.1
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• pp.33-40
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• 1986

The distribution of giant duckweed (Spirodela polyrrhiza) and small duckweed (Lemna aequinoctialis) was investigated at lead-zinc mine area and the limiting factors for their distribution were studied by laboratory experiments. The metal investigated of water affected on the growth of giant duckweed and small duckweed. Under filed conditions, both giant duckweed and small duckweed did not persist at more acidic conditions than pH 4.8 or at conditions more than 0.30 ppm of Cd concentration. Giant duckweeds were intolerable, under conditiions with less than 0.30 ppm of Cd and above than 0.07ppm of Zn, but small duckweeds were tolerable under conditions of more than 0.07 ppm of Zn concentration. However, neither can live above 7.50ppm of Zn concentration. These field observations corresponded with the results of the laboratory experiments.

• Advances in nano research
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• v.3 no.3
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• pp.123-131
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• 2015

The unintentionally doped and bismuth (Bi) doped zinc oxide (ZnO) films were prepared by spray pyrolysis at $450^{\circ}C$ with zinc acetate and bismuth nitrate precursor. The n-type conduction with concentration $6.13{\times}10^{16}cm^{-3}$ can be observed for the unintentionally doped ZnO. With the increasing of bismuth nitrate concentration in precursor, the p-type conduction can be observed. The p-type concentration $4.44{\times}10^{17}cm^{-3}$ can be achieved for the film with the Bi/Zn atomic ratio 5% in the precursor. The photoluminescence spectroscopy with HeCd laser light source was studied for films with different Bi doping. The photocatalytic activity for the unintentionally doped and Bi-doped ZnO films was studied through the photodegradation of Congo red under UV light illumination. The effects of different Bi contents on photocatalytic activity are studied and discussed. Results show that appropriate Bi doping in ZnO can increase photocatalytic activity.

• Nutritional Sciences
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• v.5 no.4
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• pp.190-196
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• 2002

Zinc deficiency has been shown to result in poor appetite, causing anorexia. However, the role of zinc in the regulation of food intake is not well understood. In the present study, we hypothesized that zinc deficiency dysregulates circulating leptin level and leptin mRNA gene expression, and that whether these changes were occuring as a direct result of, or as a compensatory effect of zinc deficiency in rats. After an adaptation period of 4 weeks, Sprague Dawley rats were provided with three different level of zinc, as one week of a Zn-adequate (30 mg/kg) diet, then two weeks of a Zn-depletion (1 mg/kg ), and finally by two weeks of a Zn-repletion (50 mg/kg) diet. At the end of each dietary experimental period, one third of the 26 rats were killed. Zinc levels of blood subfractions (plasma, yee blood cells and mononuclear cells) and in the liver were substantially decreased, despite the fact that food intake was not substantially decreased during the Zn-depletion period. Serum leptin concentration was significantly increased during the zinc depletion period. Leptin mRNA in adipose tissue was also shown to be highly expressed during the Zn-depletion period. Presumably, increased leptin level and leptin mRNA induction during Zn-depletion conditions may be the cause of lowered appetite which is the common symptom of Zn-deficiency. In conclusion, These increases in circulating leptin levels and in leptin gene expression would be the direct result of, rather than the compensatory effect of, zinc deficiency.

• Journal of Preventive Medicine and Public Health
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• v.31 no.2 s.61
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• pp.265-274
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• 1998

To investigate the change of nitric oxide(NO), copper, and zinc in serum on smoking and alcohol ingestion in young adults, this study was performed in a cross-sectional study in 127 healthy men in Korea who had HBsAg(-), HCVAb(-), and no symptomatic liver, heart, gastrointestinal, chronic diseases, and inflammatory sign(lower than 10,000 white blood cell count in CBC). At the men's entry into the study, blood samples were drawn from each subject and immediately centrifuged for analysis of NO, copper, and zinc. Each man completed a questionnaire that provided information on smoking, alcohol intake and present and past medical history NO was analyzed by HPLC(Green et al., 1982), copper and zinc by atomic absorption spectrophotometer with air-acetylene flame and total cholesterol(TC) by Spectrum EPX. Smoking(number of cigarettes per day and pack-year) and alcohol intake was grouped fertile. Copper was adjusted for age and zinc and for age and TC. NO, copper, and zinc on smoking and alcohol ingestion were analyzed in general linear models, respectively. NO, copper and zinc in serum did not show statistical differences between non-smoking and high-smoking group and no-alcohol intake and high-alcohol intake group. This study suggested that copper, zinc, and NO was not. good biological marker for early effect by smoking and alcohol intake in young adults. However, selection bias should be considered in evaluation of this result. A large prospective study will be needed in advance on usefulness of copper, zinc, and NO as a marker for risk factors and early change of atherosclerosis.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.228-233
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• 2015

This study was performed to examine the effect of zinc on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A^2/O$). The results of this study can be summarized as follows. In the case of the effect of zinc on organic treatment, zinc had no effect up to 12 mg/L with batch reactor but biodegradability was lowered when it was above 3.0 mg/L with CSTR. Concerning the case on nitrification and removal of nitrogen, nitrification rate was lowered when zinc was above 6.0 mg/L with batch reactor and removal rate of nitrogen was lowered when zinc was above 3.0 mg/L with CSTR. Removal rate of phosphorus was lowered when it was above 6.0 mg/L zinc with batch reactor and above 3.0 mg/L zinc with CSTR. In the case of OUR, it decreased as microbial activity was affected when zinc concentration was above 3.0 mg/L in CSTR.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.117-123
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• 2021

The effects of electrolyte concentration on the electrochemical properties of Fe4[Fe(CN6)]3(FeHCF) as a novel active material for the electrode of aqueous zinc-ion batteries was investigated. The electrochemical reactions and structural stability of the FeHCF electrode were significantly affected by the electrolyte concentration. In the electrolyte solutions of 1.0-7.0 mol dm-3, the charge-discharge capacities increased with increasing electrolyte concentration, however gradually decreased as the cycle progressed. On the other hand, in the 9.0 mol dm-3 electrolyte solution, the initial capacity was relatively small, however showed good cyclability. Additionally, the FeHCF electrode after five cycles in the former electrolyte solutions, had a change in crystal structure, whereas there was no change in the latter electrolyte solution. This suggests that the performance of the FeHCF electrode is greatly influenced by the hydration structure of zinc ions present in electrolyte solutions.

• Clinical and Experimental Reproductive Medicine
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• v.14 no.2
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• pp.85-92
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• 1987

To estimate the influence of plasma copper and zinc concentration on infertility, we measured copper and zinc levels in plasma of 117 infertile women and 14 infertile men by atomic absorption spectrophotometry from January, 1987 through June, 1987 and the results were as follows. 1. The mean plasma copper level was significantly lower in infertile women than in fertile control women while mean plasma zinc level significantly higher in infertile women than in fertile control women. 2. A significant difference in the mean plasma level between infertile women with tubal and endometrial factor and normal controls was noted. 3. The mean level of copper in plasma of azoospermic patients was significantly higher than in fertile control subjects. 4. In fertile control and infertile women, no diurnal and menstrual cyclic variations in plasma zinc and copper levels were present, respectively. Also, there were no significant correlation between plasma zinc and copper levels in all studied group of subjects.

• Journal of Magnetics
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• v.11 no.1
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• pp.1-4
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• 2006

We report on the growth, structural and transport properties of zinc-blende CrAs/GaAs/MnAs/GaAs multilayers on GaAs(001) substrates. Structural analyses using in-situ reflection high-energy electron diffraction and exsitu cross-sectional transmission electron microscopy confirmed the realization of a zinc-blende crystal structure. Room temperature Hall measurements reveal that the as-grown multilayer exhibits p-type conductivity with a very low resistivity of $0.052\;\omega{cm}$, a high carrier concentration of $6.2X10^{19}\;cm^{-3}$ and a Hall mobility of $1.8\;cm^2/Vs$. We also observed a clear decrease of the resistivity in samples after low temperature annealing.