• Korean Journal of Materials Research
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• v.15 no.10
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• pp.678-682
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• 2005

We studied the possibility of $Zn_4O(Ac)_2(OH)$ formation as a precursor for ZnO nano particles in sol-gel method. Four different additives such as tetra methyl ammonium hydroxide, mono ethanol amine (MEA), LiOH, and $H_2O$ were used for zinc acetate dissolved in 2-methoxy ethanol. ZnO particles of 5-6 nm in size were observed. Existence of $Zn_4O(Ac)_6$ was not verified. $Zn_4O(Ac)_2(OH)$ molecules were observed and they were believed to be the precursors of ZnO. A peak at 275nm in UV-Vis analysis was observed In the case of MEA and $H_2O$ but no ZnO particles were detected in transmission electron microscopy.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1155-1161
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• 2006

The characteristics of photocatalytic degradation of tar colorants such as brilliant blue FCF(BBF) and tartrazine(TTZ) with zinc oxide suspension was studied in a batch reactor under irradiation of ultra-violet ray. Photocatalytic degradation of TTZ with ZnO was more higher than that of BBF, and was Increased with dosage of ZnO below 5g, but was nearly affected with initial pH of two tar colorants aqueous solution. Ammonium persulfate was more effective oxidant than potassium bromate which slightly increased the degradation of BBF, but not increased the degradation of TTZ. The photocatalytic degradation rates of BBF and TTZ were pseudo-first order with rate constants of 0.0066, 0.0092 and $0.015min^{-1}$ for BBF, 0.042, 0.017 and $0.110min^{-1}$ for TTZ at the dosage of 1, 2 and 5g ZnO, respectively.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.348-352
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• 2014

In light of the sure protection function, the most important factors of a varistor are the clamping voltage ratio and degradation characteristics. The degradation characteristics of Pr/Co/Cr/Er co-doped zinc oxide varistors were investigated by impulse currents (0.4~2.1 kA) stress for the specified content of $Er_2O_3$ (0.5 and 2.0 mol%). The varistor doped with 2.0 mol% $Er_2O_3$ exhibited the best clamp characteristics, with the clamp voltage ratio (K) in the range of K = 1.63~1.88 at the impulse currents of 5-50 A. However, the varistor doped with 0.5 mol% exhibited excellent electrical stability, with variation rates for the breakdown field, for the nonlinear coefficient, and for the leakage current density of -6.9%, -12.6%, and -14.3%, respectively, after application of an impulse current of 2.1 kA. In contrast, the varistor doped with 2.0 mol% was destroyed after application of an impulse current of 1.2 kA.

• Advances in nano research
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• v.15 no.1
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• pp.67-74
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• 2023

The combination of physical activities and individual skills in sports creates an entertaining and competitive environment governed by a set of rules. In today's world, sports attract significant attention and are approached differently by various groups. Inevitably, injuries occur in sports, significantly impacting an athlete's performance and ability to participate in exercises and competitions. Addressing this issue, one of the crucial measures involves restoring the athlete's ability to engage in sports and compete. Sports rehabilitation serves as a treatment to mitigate the effects of injuries, and when combined with surgery, it can expedite the recovery process. Therefore, the primary objective of this study is to utilize a biocompatible technology for synthesizing zinc oxide (ZnO) nanoparticles in sports rehabilitation, ensuring minimal harm to the environment.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.25 no.1
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• pp.28-36
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• 2014

Objectives : The goal of this study was to examine the association between zinc and lead level and symptoms of attention-deficit hyperactivity disorder (ADHD) among Korean children. Methods : A total of 89 clinic-referred children participated in the study (ADHD group=45, control group=44). The participants were 5-15 years old, and were mainly from urban areas of Seoul, Korea. ADHD was diagnosed using the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version. We excluded children with a comorbid psychiatric disorder, medical illness requiring medication, or a prior history of taking ADHD medication. In order to evaluate the severity of ADHD symptoms, parents' Korean ADHD Rating Scale (K-ARS) was used. The ADHD diagnostic system (ADS) was used for evaluation of the severity of inattention and impulsivity. All participants completed the intelligence test and hair mineral analysis. Multiple regression analysis was used to examine the effect of hair zinc and lead levels on the K-ARS and ADS. We measured the predictive ability of the zinc and lead levels using logistic regression analysis. Results : The lead level explained the score for omission errors, commission errors, and response time SD in visual ADS in the ADHD group (adjusted $R^2$=.243, p<.01, adjusted $R^2$=.362, p<.01, and adjusted $R^2$=.275, p<.01), the score for omission errors of auditory ADS in ADHD group (adjusted $R^2$=.407, p<.01) and the entire group (adjusted $R^2$=.292, p<.01). Zinc was significantly explanatory for the K-ARS scores for the entire group (adjusted $R^2$=.248, p<.001) and the ADHD group (adjusted $R^2$=.247, p<.05). Conclusion : These findings suggest a possible role of zinc and lead in ADHD. Lead concentration in hair samples affected the ADS scores, and this was more prominent in children with ADHD. Children with ADHD had a lower zinc concentration in their hair, and the zinc concentration in hair showed negative correlation with the K-ARS score.

• Journal of Nutrition and Health
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• v.54 no.6
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• pp.594-602
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• 2021

Purpose: The zinc transporter ZIP7 is known to regulate glucose metabolism in skeletal muscles, and skeletal muscles are known to play a critical role in glycemic control. The present study examines the effects of dietary zinc supplementation on the blood glucose concentration and expression of ZIP7 in skeletal muscle obtained from obese mice fed a high-fat diet (HF). Methods: C57BL/6J male mice were divided into three groups and were administered either a HF (60% of total calories from fat), HF supplemented with zinc (HF+Zn, 60% calories from fat + 300 mg zinc/kg diet), or low-fat diet (CON, 10% calories from fat), for 15 weeks. Results: Compared to CON group mice, the final body weights and adipose tissue weights were significantly increased, while the skeletal muscle weights were significantly decreased in mice belonging to the HF and HF+Zn groups. The HF+Zn group had significantly lower levels of fasting blood glucose concentrations than the HF group. Similarly, zinc supplementation significantly decreased the HF-elevated area under the curve values obtained from the oral glucose tolerance test. Skeletal muscle protein levels of ZIP7 in samples obtained from the HF group were significantly decreased as compared to the CON group. Conversely, the skeletal ZIP7 protein levels in the HF+Zn group were significantly increased as compared to the HF group. Moreover, the protein levels of phosphorylated-AKT and glucose transporter 4 in the skeletal muscle were significantly increased subsequent to zinc supplementation. Conclusion: Our data demonstrates that zinc supplementation up-regulates the skeletal muscle ZIP7 expression, which is associated with improved glucose tolerance in the obesity.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.1
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• pp.14-22
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• 2006

Purpose: To identify factors that influence serum zinc concentrations in children with acute gastroenteritis. Methods: Thirty-two children under 5 years of age (15 boys and 17 girls) were selected randomly among those who visited to an pediatric emergency room of Ehwa Womans University Mokdong Hospital with acute gastroenteritis from May to August 2005. This study estimated the association between serum zinc concentrations and clinical, biochemical variables in patients with acute gastroenteritis. Results: Serum zinc concentration was lower in febrile patients than afebrile patients with acute gastroenteritis ($67.5{\pm}25.3$ vs $85.5{\pm}14.2$, p<0.05). It also was lower in patients with positive C-reactive protein (CRP) than those with negative CRP ($63.9{\pm}25.4$vs $86.7{\pm}13.8$, p<0.05). Serum zinc concentration was negatively correlated (r=-0.494, p<0.05) with CRP concentration, whereas positively correlated with hematocrit (r=0.370, p<0.05), total protein (r=0.474, p<0.05), and albumin (r=0.636, p<0.05). Twelve patients (37.5%) showed very low serum zinc concentration (< $70{\mu}g/dL$) without clinical symptoms of deficiency or growth retardation. Frequency of febrile illness or positive CRP is significantly greater in group with zinc < $70{\mu}g/dL$ than the group with zinc ${\geq}70{\mu}g/dL$ (91.7% vs 55%, p<0.05; 91.7% vs 40%, p<0.05, respectively). Conclusion: In patients with acute gastroenteritis, serum zinc concentration was influenced by various factors such as fever, CRP, and biochemical factors. For evaluating zinc status in the body. factors.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.135-151
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• 1982

In order to investigate the effectiveness of Osmose process for the practical treatment of wood this study has been made using water soluble preservatives such as Malenit and chromated zinc chloride. The results obtained in this investigation are as follows: 1. The penetration of Malenit in sapwood has been observed deeper than that of chromated zinc chloride for all species tested in this investigation. 2. The penetration of preservatives applied in soft wood, ie. Pinus densiflora and Larix leptolepis has been observed better results than that of hard wood, i.e., Quercus accutissima and Carpinus laxiflora. 3. The longer stack covering, despite of preservatives applied and size of wood tested, has given better penetration for all species tested, and the fastest diffusion has been occured in 15 days from they day started. Following after 15 days diffusion had gradualy become slower. 4. The length of time needed for effective penetration has taken 45 days for all species tested, reaching twenty millimeters (20mm) in depth in case of Malnit, that means also more than 50% of penetration into sapwood portion. However it has taken 45 days fer Pinus densiflora and Larix leptolepis, reaching fifteen millimeters (15mm) and 60 days for Quercus accutissima and Carpinus laxiflora, reaching same fifteen millimeters in case of chromated zinc chloride, that means also less than 50% (except 50% for Larix) of penetration into sapwood portion. 5. Deeper penetration of preservatives from the wood surface has been observed in the larger wood than the smaller wood for all species tested, although the penetration ratio between the width of sapwood and the length penetrated has been observed smaller in larger wood than smaller wood. 6. The relation between moisture content of wood and the penetration of preservatives into wood tested has shown the linear regression, that is, the more moisture content brought the deeper penetration. 7. Following the result obtained at this investigation osmose process with Malenit applied has indicated as a useable process for the none pressure treatment of wood.

• Journal of the Korean Magnetic Resonance Society
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• v.14 no.2
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• pp.117-126
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• 2010

Hsp33 is a molecular chaperone achieving a holdase activity upon response to a dual stress by heat and oxidation. Despite several crystal structures available, the activation process is not clearly understood, because the structure inactive Hsp33 as its reduced, zinc-bound, monomeric form has not been solved yet. Thus, we initiated structural investigation of the reduced Hsp33 monomer by NMR. In this study, to overcome the high molecular weight (33 kDa), the protein was triply isotope-[$^{13}C$, $^{15}N$, $^2H$]-labeled and its inactive, monomeric state was ensured. 2D-[$^1H$, $^{15}N$]-TROSY and a series of triple resonance spectra could be successfully obtained on a high-field (900 MHz) NMR machine with a cryoprobe. However, under all of the different conditions tested, the number of resonances observed was significantly less than that expected from the amino acid sequence. Thus, a possible contribution of dynamic conformational exchange leading to a line broadening is suggested that might be important for activation process of Hsp33.

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.78-82
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• 2004

The solvothermal reaction of zinc(H) nitrate $(Zn(NO_3)_2\;{\cdot}\;6H_2O)$ with $ATP(2-aminoterephthalate,\;H_2N-C_6H_3-1,4-(COO)_2)$ in a mixture of solvents of DMF and ethanol, in the presence of benzene, gave a 2 dimensional zinc polymer [Zn(ATP) (DMF)] (1). X-ray structure determination revealed that two zinc metals and four ATP ligands form the paddle-wheel SBUs, which are linked by the ATP ligands to give a 2-D square-grid network. Each square grid has approximate dimensions of $11.1\times11.1\;{\AA}$ based on Zn metals. Benzene was required to produce high-quality crystals of polymer 1.