• The Korean Journal of Ceramics
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• 제3권4호
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• pp.269-273
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• 1997

Chemical composition of cement powder influences the setting time and early compressive strength development. The setting time increases as the amounts of zinc oxide and magnesium oxide are increased. For one day compressive strength development, a cement powder with a composition 90% ZnO, 8% MgO and 2% silica resulted in the highest strength (greater than 1, 090 kg/$\textrm{cm}^2$). Cement-forming liquids also need to be buffered, with both aluminum and zinc ions, for a good consistency and a higher strength of the zinc phosphate cement. These liquids control the setting reactions.

• 한국인쇄학회지
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• 제16권2호
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• pp.11-22
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• 1998

For the purpose of preparation of monodispersed spherical zinc oxide fine particles, an experimental research on the preparation of zinc oxide particles from zinc salts solutions by high temperature precipitation reaction was performed. Zinc oxide particles were precipitated from all the precipitation solutions tested if the precipitation temperature was higher than 60$^{\circ}$. As the precipitation temperature Increased until 80$^{\circ}$, the average particle diameter of zinc oxide particles decreased and the narrower particle size distribution were obtained. Spherical zinc oxide fine particles with relatively narrow particle size distribution were precipitated from the ZnSO$_4$ solutions with NaOH as precipitant. Final pH of precipitation solution had an effect on the amount of zinc oxide precipitated, but had no effect on the their particle size or size distribution.

• Journal of Nutrition and Health
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• 제4권3호
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• pp.1-4
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• 1971

Zinc is an essential trace element. Previos methods for the determination of zinc in serum have been difficult and reported findings must be treated with caution. The normal range of zinc in serum varies significantly according to different methods and author. The scope of this work was to establish the normal range of zinc in serum values in healthy Korean persons. Methods are described for the determination of zinc in serum diluted ten-fold with deionised water using Hitachi Model 207, atomic absorption spectrophotometer. The values of zinc in serum of 23 healthy Korean persons by atomic absorption spectroscopy ranged from 87.6 to $131.2\;{\mu}g/100\;ml$ with the mean value $109.1\;{\mu}g/100\;ml$ and standard deviation 10.86. In this method, satifactory result was obtained with regard to the coefficient variation and recoveries of added zinc in the measurenents.

• 한국임상수의학회지
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• 제14권2호
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• pp.361-364
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• 1997

The paper is to report a case of zinc-deficient parakeratotic hyperkeratosis in a dog. In this dermatosis, although an available diagnosis of zinc-deficient dermatosis is to analyse the serum or hair zinc Bevels, exact analysis of zinc is difficult and unreliable due to contamination of zinc by various environmental, physiologic and disease-related factors. Diagnosis may be performed by history, physical examination and blood chemical analysis. Laboratory evaluation revealed hypercholesterolemia and low activities of serum alkaline photophatase and total protein. The dog showed thick crusts at the elbows joint, stifle joint and testis. Zinc sulfate is administered per oral to patient with application of salicylic acid added vaseline ointment on hyperkaratic lesions. The dog is successfully cured.

• 한국표면공학회지
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• 제22권3호
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• pp.118-127
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• 1989

The rate of electrodeposition Zinc-nickel alloy on to electrolytic ione in sulface solution both under an inter and air atmospherss has studied by use of a rotating disc geometry. The kinetics shows 1st order reaction, and the rate constants are proportional to the square root of rpm, however, they are less than the valuse suggested by Levich. The rate constants of zinc deposition approach the total mass transfer rate constants with increasing potential and deviate with increasing rotaing speed, but those of nickel deposition are constant. Below $40^{\circ}C$ the activation engrgies of zinc deposition and nikel deposition were 4.4Kcal/mol and 6.3Kcal/mol respectively. There results show that overall reaction rate of zinc-nickel plaeting is controlled by mixed reaction and zinc deposotion is more affected by mass transfer reaction than nickel. The current density for the zinc-nickel plating was less in an air atmosphere than in a nitrogen atmosphere. The cathode efficiency increased with decreasing cathode rotating speeds, potentials, and increasing temperatures. Zzinc-nickel platings are more improved in microhardnss than zinc platings.

• Journal of Plant Biology
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• 제20권1호
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• pp.45-52
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• 1977

During the period of 1975-76, a survey was carried out to find out zinc indicators in the natural vegetation in Korea. The symptoms fo chlorosis were observed in flowering plants in the areas of zinc outcrop of Wolgok-A, Seokgok-9, and Sowolgok. Although 28 species were found to be chlorotic, the total quantity of chlorotic foliage observed was small. Reasons for chlorosis in the areas of zinc are deposits is considered as effects of zinc, lead, copper and calcium ions. Sedum sp. and Dianthus sinensis were confined to soil containing more than exchangeable zinc of 30 ppm and to accumulation in the plants contained at least 1,300-14,000 ppm of zinc. Therefore Sedum sp. and Dianthus sinensis might be used as zinc indicators in Korea.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1717-1724
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• 2004

The study was conducted to determine the effect of Salmonella typhymurium lipopolysaccharide (LPS) challenge on egg-laying performance, inflammatory response, zinc metabolism in layer fed diets supplemented with organic or inorganic zinc since 3-wk-old. The three dietary treatments were corn-soybean meal basal diet without supplemental zinc or with supplemental zinc at 60 mg/kg zinc from $ZnSO_4$ or zinc amino acid complex (ZnAA). At the age of 58 wk-old, twelve hens from each dietary treatment were allotted into two sub-groups. On day 1, 3, 5, 7 of the $58^{th}$ week of age, six birds of one sub-group were injected intraperitoneally (i.p.) with 2 ml LPS (1.0 $\ell$/ml) or sterile saline. Neither zinc source ${\times}$ immune challenge interaction nor zinc source effect on egg production performance was observed (p>0.05), LPS-challenge decreased egg production (p<0.04) and increased percentage of cracked eggs (p <0.01). With LPS challenged, the fever response of hens fed ZnAA peaked and subsided earlier than in hens fed $ZnSO_4$ or basal diet. Serum IL-1$\beta$ at 3 h was higher (p<0.01), but lower (p<0.001) at 12 h post-challenge with LPS in hens fed ZnAA than $ZnSO_4$. In salinetreated groups, serum IL 1$\beta$ was higher in hens fed ZnAA than the basal diet at 3 h post-injection (p<0.01). LPS-challenged birds had lower serum zinc and higher zinc sequestered in liver and spleen (p<0.001). In saline-treated birds, there was no difference in zinc concentration of serum, liver and spleen among different dietary treatments (p>0.05). Supplementation of 60 mg/kg zinc from either ZnAA or $ZnSO_4$ significantly (p<0.05) elevated metallothionein (MT) concentration in liver and spleen. MT concentration in liver of birds fed ZnAA diet was higher than in those fed $ZnSO_4$ diet (p<0.05). The magnitude of increase of hepatic and splenic MT due to LPS challenge was higher by supplementation of ZnAA than $ZnSO_4$. The results suggest that zinc amino acid complex enhanceed MT synthesis and zinc sequestered in liver and spleen and increased the sensitivity to immune response due to LPS challenge.

• Asian Pacific Journal of Cancer Prevention
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• 제13권2호
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• pp.487-492
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• 2012

Trace element zinc deficiency or excess is implicated in the development or progression of some cancers. The exact role of zinc in the etiology of colon cancer is unclear. To cast light on this question, an experimental model of colon carcinogenesis was applied here. Six week old rats were given sub cutaneous injections of DMH (30 mg/kg body weight) twice a week for three months and sacrificed after 4 months (precancer model) and 6 months (cancer model). Plasma zinc levels showed a significant decrease (p<0.05) at 4 months and a greater significant decrease at 6 months (p<0.01) as compared with controls. In the large intestine there was a significant decrease in tissue zinc levels (p<0.005) and in CuZnSOD, and alkaline phosphatase activity (p<0.05) in the pre-cancerous model and a greater significant decrease in tissue zinc (p<0.0001), and in CuZnSOD and alkaline phosphatase activity (p<0.001), in the carcinoma model. The tissue zinc levels showed a significant decrease in the small intestine and stomach (p<0.005) and in liver (p<0.05) in the cancer model. 87% of the rats in the precancer group and 92% rats in the cancer group showed histological evidence of precancerous lesions and carcinomas respectively in the colon mucosa. This study suggests that the decrease in plasma zinc, tissue zinc and activity of zinc related enzymes are associated with the development of preneoplastic lesions and these biochemical parameters further decrease with progression to carcinoma in the colon.

• Applied Microscopy
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• 제40권1호
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• pp.15-19
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• 2010

이번 연구에서는 성체 랫드(Sprague-Dawley)의 척수신경절내 분포하는 zinc의 분포 관찰하기 위하여 zinc selenium autometallograpy(AMG)로 염색하였다. H-E염색표본에서 척수신경절 속에는 신경절세포들이 무리지어 분포하고 있었고, 세포체는 둥글거나 타원형이었으며, 작은 신경절세포, 큰 신경절세포로 대별되었다. 모든 신경절세포의 세포체는 한 층의 납작한 위성세포(satellite cell)에 의하여 둘러싸여 있었다. AMG 염색표본에서는 작은 신경절세포의 경우 강한 양성반응이 핵 주변부에서 관찰되었으나, 큰 신경절세포의 경우 전반적으로 미약한 AMG 양성반응을 보였고, 염색양상도 서로 달랐다. 그러나 큰 신경절세포를 둘러싸는 위성세포에서는 뚜렷한 AMG 양성반응이 관찰되었다. 이러한 조직화학적 본 연구의 결과는 zinc가 감각신경절인 랫드 척수신경절에서 통증을 포함한 감각의 전달과정에 의미있는 기능을 영위할 수 있음을 시사한다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권4호
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• pp.259-268
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• 2016

Purpose: Zinc deficiency can induce serious clinical problems in the gastrointestinal (GI) system and immune system and can affect growth and development. It is more severe in younger patients. Chronic zinc deficiency is reflected more precisely in hair than in serum. We studied hair zinc levels and other hair and serum micronutrients in chronic malnourished children to identify which micronutrients are affected or correlated with the other ones. Methods: Hair mineral analyses were performed in 56 children (age, 1-15 years) presenting with malnutrition, poor growth, poor appetite, anorexia, with/without other GI symptoms (diarrhea, abdominal pain, constipation) from August 2012 to March 2015. Biochemical studies for macronutrients and major micronutrients were also conducted. Results: Hair zinc deficiency was diagnosed in 88%, and serum zinc deficiency was diagnosed in 55% of the children. There was no statistical correlation between serum and tissue zinc level. Hair zinc levels were highly correlated with serum vitamin D (r=-0.479, p=0.001), which also showed correlation with hair levels of magnesium and calcium. (r=0.564, 0.339, p=0.001, 0.011). Hair calcium level was correlated with serum pre-albumin (r=0.423, p=0.001). These correlations may explain the phenomenon that the major clinical manifestation of zinc deficiency is poor body growth. Clinical symptoms were resolved in most children after zinc supplementation. Conclusion: Hair zinc and mineral analyses are useful as a therapeutic guide in the clinical investigation of children with malnutrition and poor growth.