• Journal of Nutrition and Health
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• v.23 no.4
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• pp.237-247
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• 1990

This study was to investigate the effect of zinc supplementation on serum cholesterol concentration of young women. Thirty healthy students were divided into Zn and placebo groups, and were orally given with zinc(50mg/day, 220mg as ZnSO4·7H2O) or placebo for 2 month (June 9-August 7, 1988). Changes of plasma zinc, serum total cholesterol, HDL-cholesterol (HDL-C), LDL-cholesterol(LDL-C) and total lipid were analyzed from the initiation to 1 month after the end of zinc supplementation at monthly interval. Plasma zinc, serum LDL-C content and LDL-C/HDL-C were significantly increased by zinc supplementation. Serum total cholesterol content tended to be increased by zinc supplementation but was not significantly different between the two groups. Serum HDL-C content was significantly decreased by zinc supplementation. Serum total lipid content was not different between the two groups during experimental period. Thus, in this study considering the effect of zinc supplementation on serum cholesterol concentration, we conclude that the effect of zinc supplementation on coronary heart disease may be negative.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.1
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• pp.80-86
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• 1990

This experiment was conducted to study the effects of dietary zinc and ethanol on the zinc content of serum and tissues. Eight male rats of Sprague-Dawley strain with average weight of 80$\pm$5g were divided into five groups such as C group: ad libitum control diet(100 ppm Zn) plus isocaloric sucrose solution CE group ; ad libitum control diet plus 25% ethanol solution PF group ; pair fed control to zinc deficient diet(5ppm Zn) plus isocaloric sucrose solution ZD grop ; ad libitum zinc deficient diet plus isocaloric sucrose solution and ZDE group ; ad libitum zinc deficient diet plus 25% ethanol solution. The rats were sacrificed after 4 and 7 weeks of feeding periods. The liver weights of ZD and ZDF groups were increased however the weight of testis was decreased in the same groups The content of serum zinc was infiuenced by the dietary zinc level and the amount was significantly decreased in the ZD group. The content of liver zinc was influnced by the dietary zinc level and the amount was decreased by ethanol feeding. The content of testis zinc was significantly low in the ZDE group. The zinc level of feces to be increased by the ethanol feeding.

• Journal of the Korean institute of surface engineering
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• v.32 no.1
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• pp.31-42
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• 1999

The effect was investigated that aluminium in the zinc bath has on the coating adhesion of Hot-rolled Galvanized Iron(HGI) manufactured without pickling process. It is thought that the coating adhesion of HGI manufactured without pickling process is good due to the fact that increasing aluminium content in the zinc bath makes zinc and aluminium diffuse to the cracks or pores in the scale formed through the reduction heat treatment, and Fe-Zn-Al compound with good ductility is formed in the scale layer and plays a role of anchor between zinc coating and substrate. It is possible that HGI with the good coating adhesion was produced without pickling treatment in the zinc bath with more that 3wt% of Al content even at the $550^{\circ}C$ of conventional reduction heating temperature. In creasing the temperature of heating section and aluminium content in the zinc bath prevents the Zn-Fe alloy. The corrosion resistance of HGI manufactured without pickling process is excellent because of the mixed reaction of zinc sacrifice and aluminium passivity film.

• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.389-396
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• 1998

This study was intended to examine the zinc status and effect of zinc supplementation on the zinc nutritional status of the elderly living in the Ulsan area. The zinc intake of 207 subjects(male 97, female 110) was measured by a 24-hour dietary recall and food frequency method. Biochemical analysis were conducted from blood and urine samples to evaluate the changes of zinc nutriture with zinc supplementation. The average dietary zinc intake of subjects was $7.7\pm{2.8mg}$ for male and $7.5\pm{2.6mg}$ for female, which were 51.3% and 62.3% of Korean RDA respectively. The first source of zinc was cereal and grain(36%), and the second was eggs and milk group(27%). After 8 weeks of zinc supplementation, the serum zinc content was significantly increased(p<0.01), although the serum copper content was not significantly decrease. Serum HDL- cholesterol level was not significantly decreased with zinc supplementation. Serum alkaline phosphatase(ALP) activity and urinary zinc excretion were significantly increased(p<0.05). The urinary Zn/Cr was not significantly increased. It is suggested from the results that the daily zinc supplementation can be effective to improve zinc nutriture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.163-165
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• 1999

The study was conducted to find the critical concentrations of zinc toxicity and to determine the changes of the contents of free proline and organic acids with treatment of different zinc chloride concentrations during rice germination and seedlings grown for seven days. The concentration of zinc chloride, 140 ppm, inhibited root elongation as much as 46 times compared with the control, and the germination rate was also decreased in all treatments of zinc chloride, showing that the germination rate decreased more with increasing concentrations of zinc chloride. Its rate was only 13% with treatment of 140 ppm zinc chloride. The content of free proline with treatment of zinc chloride, 140 ppm, was highest about 4,873 $\mu$M at 3 days compared with the control. Malic acid concentration with treatment of zinc chloride, 140 ppm, increased to approximately 4 times compared to the control. Citric and succinic acid content were also slightly increased in all treatments of zinc chloride.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.1
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• pp.27-33
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• 2004

The objectives of the present study were to measure the content of iron, copper and zinc in human milk and to estimate the intake of iron, copper and zinc of breast-fed infants during the early period of lactation. Twenty-five lactating women who delivered in a hospital in Seoul volunteered for the study. Milk samples were collected at day 2, 3, 4, 5, 6, 7, 15 and 30 postpartum. The contents of iron, copper and zinc were determined using the atomic absorption spectrophotometer after wet digestion. The intakes of iron, copper and zinc of infants were estimated by multiplization with the infant milk intake reported in our laboratory. The content of iron was 0.58 $\mu\textrm{g}$/g in colostrum, 0.48 $\mu\textrm{g}$/g in transitional milk and 0.39 $\mu\textrm{g}$/g in mature milk while the estimated iron intake of infants was 271, 255 and 259 $\mu\textrm{g}$/day, respectively. The content of copper in the milk was 0.45 $\mu\textrm{g}$/g in colostrum, 0.43 $\mu\textrm{g}$/g in transitional milk and 0.33 $\mu\textrm{g}$/g in mature milk while the estimated copper intake of infants was 210, 229 and 220 $\mu\textrm{g}$/day, respectively. The content of zinc in the milk was 5.24 $\mu\textrm{g}$/g in colostrum, 3.70 $\mu\textrm{g}$/g in transitional milk, 2.93 $\mu\textrm{g}$/g in mature milk while the estimated zinc intake of infants was 2452, 1968, and 1949 $\mu\textrm{g}$/day, respectively. These results suggest that copper and zinc intake of infants are met to RDA but iron is not.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.309-315
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• 1990

The purpose of this study was to evaluate the effect of zinc administration on the autistic children. The subject diagnosed as infantile autism were 24 male and 10 female children of a special school in Taegu city. Control group were selected from 1:2 ratio matched with cases on sex and age. The results were as followings. In female autistic group, the mean content of zinc in hair was significantly lower than control group, but in male the result was inverse at all age group. The content of zinc in hair showed significant correlation with age in male autistic group and control group. Zinc content of hair, age and sex accounted for 37.2% of the variance of autistic score and the most significant variable was zinc content. Autistic group were divided into two group. Group I which zinc content of hair below 150 ppm were administrated with multi-vitamin contained 10 mg of zinc, Group II which zinc content of hair above 150 ppm were administrated with placebo. Total administration period was eight weeks. In zinc administration group, there was a decreasing tendency of autistic score as the zinc content of hair was increased but the relationship was not statistically significant.

• Korean Journal of Veterinary Research
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• v.21 no.1
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• pp.51-58
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• 1981

Two experiments were conducted to establish a program for the prevention of swine parakeratosis occurred recently in Korea. In the first experiment, 11 rations which were considered to be related clinico-pathologically to the incidence of parakeratosis and 5 rations not to be related were collected at farms during the period from June, 1979 to December, 1980. In addition, 23 commercial rations and 10 ingredients were also collected at feed dealers or farms. The feed samples were analyzed for calcium, zinc and unsaturated fatty acid. In the second experiment, the efficiencies of adding zinc carbonate (150mg/kg diet) with or without soybean oil (5ml/kg diet) to two control rations were tested using 20 weanling pigs. One of the control rations had low zinc (41mg/kg) and normal calcium (0.64%) and the other low zinc (57mg/kg) and high calcium (1.42%). The results obtained are as follow: 1. Content of zinc in the rations induced parakeratosis ranged from 35 to 80mg/kg with a mean of 49mg/kg; whereas those of rations not induced ranged from 97 to 182mg/kg with a mean of 182mg/kg. The difference between two means was highly significant (p<0.01). 2. The calcium content in rations related to parakeratosis was ranged from 0.56 to 1.80% with a mean of 1.30% whereas that of not related was ranged from 0.63 to 1.37% with a mean of 1.07%. The highly significant difference of calcium content between two rations were recognized (p<0.01). The calcium contents of both rations were markedly higher than that of generally recommended value of 0.40~0.80%. 3. The contents of unsaturated fatty acid in induced rations was a mean of 4.42% and it was significantly lower (p<0.01) compared with those in not induced rations with a mean of 6.70%. The content of unsaturated fatty acid of commercial rations was ranged from 5.25 to 7.81% with a mean of 6.29%. 4. Zinc content of 15 commercial ration samples among 23 were less than 97mg/kg and 21 rations contained more than 1.03% of calcium. 5. Addition of zinc carbonate to the two control rations which are low in zinc content or high in calcium content were resulted in preventive effect on the incidence of swine parakeratosis. 6. It may be concluded that the incidence of swine parakeratosis was closely related to the low zinc, excess calcium and low unsaturated fatty acid in rations, most of the commercial rations contained low in zinc and high in calcium as compared with the recommended contents. Content of Unsaturated fatty acids in the commercial rations, however, were sufficient for the prevention of parakeratosis in swine.

• Corrosion Science and Technology
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• v.18 no.1
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• pp.24-32
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• 2019

The effects of zinc coating and heat treatment on the corrosion resistance of aluminum alloys including A1100 and the modified A3003, used as heat exchanger tube were investigated in this study. The grain size of the heat-treated specimen is larger than that of the specimen without heat treatment, but the grain size did not significantly affect the corrosion behavior. The concentration of zinc was noted at 11.3 ~ 31.4 at.% for the as-received Zn-coated samples and reduced to 1.2 ~ 2.4 at.% after the heat treatment, as measured by the scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS) on the surface. The concentration of oxygen is 22 ~ 46 at.% for the zinc coated specimens while noted at 7.4 ~ 12.8 at.% for the specimens after the removal of the coating. The corrosion behavior depended largely on the concentrations of zinc, aluminum, and oxygen on the specimen surface, but not on the Mo content. The corrosion potential was high and the corrosion rate was low for a specimen with a low zinc content, a high aluminum content, and a high oxygen content.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.133-134
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• 1982

This experiment has been made to investigate the absorption of watersoluble zinc chloride by Pinus densiflora S. et Z. at different moisture content, under soaking process, to decide the optimum content condition for the maximum absorption of zinc chloride by the wood tested and to investigate the concentration of zinc chloride affecting each moisture content of wood. Material was cut in the Dept. of Forest, College of Agr. S.N.U. Suwon, Korea. Sample was divided into sap and heartwood group and cut $2{\times}2{\times}2\;cm$ in size, having exact three dimensions, using the part of D.B.H. The numbers of sample were 20 pieces for each moisture content condition for both sap and heartwood. Especially, the samples were protected from exposure to keep moisture content in green condition. The ranges of moisture content tested were as the table 3 and 4. The conclusions were as follows: 1. With 3% zinc chloride solution, the rate of absorption decreased with the time increased, if the air seasoned Korean red pine (Pinus densiflora S. et Z.) was treated in steeping process. Initial absorption for 30 minutes was more than 50% of total absorpon for 24 hours. 2. Rate of absorption was same under the green condition, while rate of absorption under the moisture content 7 to 30% varied. 3. Although it was not quite proportional change in the absorption with the difference of moisture content, the great change in the absorption occured by seasoning. With exception sap green condition, sapwood twice more permeable than the heartwood in the oven dried condition and it has been observed the nearly same amount of absorption at the moisture content of 7%, 10% and 15% respectively in heartwood. 4. It was better from water in wood from view-point of absorption of zinc chloride solution, but it was difficult practically to obtain the smallest moisture content, and then it was decided that values of allowable moisture content, on the basis of mean absorption, were 15% to 20% in the sapwood, and in the heartwood, 10% to 15%. The mean absorption for each moisture content in the sap and the heartwood were as following. 5. In general, the concentration of zinc chloride after steeping was nearly same between moisture content and sap and heartwood respectively.