• Journal of Nutrition and Health
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• v.48 no.6
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• pp.468-475
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• 2015

Purpose: Genetic polymorphisms in antioxidant defense and detoxification genes may modulate the levels of oxidative stress biomarkers. Methods: A total of 301 healthy preschool-aged children in the Seoul and Kyung-gi areas were recruited. DNA was extracted from blood for genotyping of manganese superoxide dismutase (Mn-SOD) Val16Ala, glutathione S-transferase (GST) P1 Ile105Val, GSTT1 present/null, and GSTM1 present/null polymorphisms by PCR-restriction fragment length polymorphism or multiplex PCR analyses. In addition to a questionnaire survey, the levels of urinary 8-hydroxyl-2-deoxiguanosine (8-OHdG) and plasma malondialdehyde (MDA) were measured by ELISA. Results: Significantly higher urinary 8-OHdG concentrations were observed in GSTP1 Ile/Val + Val/Val genotype (p = 0.030), and tended to be higher in Mn-SOD Val/Val genotype (p = 0.065). On the other hand, exposure to environmental tobacco smoking (ETS) and interaction between ETS and gene polymorphisms did not significantly influence either urinary 8-OHdG concentrations or serum MDA. Conclusion: Based on our findings, GSTP1 Ile/Val gene polymorphisms might modulate the levels of oxidative stress biomarkers in healthy preschool children.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.68-73
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• 2016

Ammonia is very toxic, and causes neuronal damage via excitotoxicity, oxidative stress, and inflammation. Because the liver is the primary organ for ammonia metabolism, compromised liver function can result from inborn errors of metabolism. Measurement of blood ammonia has some limitations. Recently, several laboratories examined possible concurrent increases in plasma ammonia. However, the collection, handling, storage, and analysis of blood samples are all potential sources of error. For evaluation of rapidity and reliability of measurement of blood ammonia, the DRI-CHEM 100 (Fuji Film Co., Japan) and COBAS 8000 (Roche Diagnostic Ltd., Switzerland) analyzer were used for analysis of ammonia level values. The results of this study detected a high correlation between analyzer. Therefore, one-step measurement was suitable for ammonia analysis. After sampling of the ammonia in the time slot for measurement an increase to 46.5, 57.4, and 79.0 (${\mu}g/dL$) was observed at 30, 90, and 180 minutes. In addition, specific capacity of the ammonia, 7, 10, and 13 (${\mu}L$), was measured as 39, 46, and 43 (${\mu}g/dL$), respectively, and the FDC-100 analyzer was more effective in $10{\mu}L$ (p<0.001). In conclusion, the evaluated analysis may offer useful information for clinical application.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.421-422
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• 2011

The first part is about development of a liquid target for a neutron source, which is designed to overcome many of the limitations of traditional beam-target neutron generators by utilizing a liquid target neutron source. One of the most critical aspects of the beam-target neutron generator is the target integrity under the beam exposure. A liquid target can be a good solution to overcome damage to the target such as target erosion and depletion of hydrogen isotopes in the active layer, especially for the one operating at high neutron fluxes with no need for water cooling. There is no inherent target lifetime for the liquid target neutron generator when used with continuous refreshment of the target surface exposed to the energetic beam. In this work, liquid target containing hydrogen has been developed and tested in vacuum environment. Potentially, liquid targets could allow a point neutron source whose spatial extension is on the order of 1 to $10{\mu}m$. And the second is about the vacuum ultraviolet (VUV) spectrometer which is designed as a five-channel spectral system for ITER main plasma measurement. To develop and verify the design, a two-channel prototype system was fabricated with No. 3 (14.4 nm~31.8 nm) and No. 4 (29.0 nm~60.0 nm) among the five channels. For test of the prototype system, a hollow cathode lamp is used as a light source. The system is composed of a collimating mirror to collect the light from source to slit, and two holographic diffraction gratings with toroidal geometry to diffract and also to collimate the light from the common slit to detectors. The two gratings are positioned at different optical distances and heights as designed. To study the appropriate detector for ITER VUV system, two different electronic detectors of the back-illuminated charge coupled device and the micro-channel plate electron multiplier were installed and the performance has been investigated and compared in the same experimental conditions. The overall system performance was verified by measuring the spectrums.

• Journal of Life Science
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• v.25 no.5
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• pp.539-547
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• 2015

This study aimed to investigate the protective effect of Semisulcospira libertina extract on liver injury induced by D-galactosamine in rats. After the administration of S. libertina extract, the local fat degeneration and infiltration of inflammatory cells in liver tissues were significantly decreased and peripheral hemorrhages around portal triads and central necrosis around central veins were found to be protective. The elevated levels of plasma ALT, AST, and LDH, the ALP activation lipid peroxidation, and the lipid contents of a damaged liver were recovered in experimental rats administrated with S. libertina extract, suggesting its role in blood enzyme activation and lipid content restoration within damaged rat liver tissues. Moreover, the expression rate of TNF-α, which accelerates inflammation and induces tissue damage and necrosis, was significantly decreased. In addition, the activities of antioxidant enzymes were more effectively upregulated compared to those of the control group induced hepatotoxicity. All data showed that S. libertina extract has a preventive role against liver damages, such as inflammation and tissue necrosis, as instigated with D-galactosamine by improving the activities of blood enzymes and antioxidant enzymes and modulating the expression of inflammation factor, suggest S. libertina extract is an effective medicinal resource for the restoration of hepatotoxicity.

• Journal of Life Science
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• v.30 no.7
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• pp.630-633
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• 2020

Renal failure syndrome in wild mammals is infrequently reported. Muskrat (Ondatra zibethicus) is a medium-sized rodent known to carry many diseases but rarely exhibiting renal failure. A six-month old female muskrat was submitted to our laboratory for pathological diagnosis, and necropsy revealed severe renal damage with sand-like lithiasis in the ureter, renal calculi, and hydronephrosis. All major organs, including the cerebrum, also showed systemic hemorrhage and calcification which may have been due to uremia induced by renal failure. Histopathologically, necrosis and microcalcification were detected in the renal cortex and the medulla, especially in the proximal convoluted tubules and collecting ducts of the kidney. Significant hyalinization of the glomeruli was also observed, and this suggested chronic nephritis. These findings would support mycotoxic effects, particularly on the kidney. Moreover, infiltration of neutrophils and mononuclear cells was observed in the lung and of plasma cells in the spleen. The definitive cause of the toxic effects in this case of muskrat renal failure could be attributed to contaminated food.

• Journal of Life Science
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• v.19 no.8
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• pp.1112-1118
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• 2009

In the present study, the effects of muddy water were compared and examined on the fish inhabiting Imha reservoir, E. erythropterus, H. labeo and Z. platypus in Cypriniformes, S. asotus in Siluriformes and S. scherzeri in Perciformes. In the gills of fish in muddy water, the secondary lamellae of fish in Cypriniformes showed more irregular gaps and more winding than those in Siluriformes and Perciformes. Also, the edema and detachment of epithelial cells was more detected in the gills in Cypriniformes, but clubbing was frequently detected in Perciformes and Siluriformes. Also, we found that muddy debris and minute particles attached to lamellae were frequently detected in Perciformes and Cypriniformes. The glomerulus in the kidney was much more constricted in Z. platypus in Cypriniformes. As a result, it is proposed that fish in Cypriniformes are more affected by muddy water. In the changes of blood components, which might be affected by muddy water, the concentrations of TP, ALB, TG, CHOL and A/G ratio, were high in Cypriniformes, and inorganic matters were abundant in Siluriformes. In addition, AST activity was relatively higher than ALT and both activities were higher in Cypriniformes than in Siluriformes. Taken together, the change in blood plasma may be caused by the reduction in voracity in the wake of muddy water, which results in tissue damage.

• Journal of Life Science
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• v.23 no.7
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• pp.904-912
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• 2013

This study aimed to evaluate the protective effect of cordycepin-increased Cordyceps militaris strain on carbon tetrachloride ($CCl_4$)-induced hepatotoxicity and oxidative stress in rats. Male Sprague-Dawley rats were randomly divided into five groups (n=6) based on six dietary categories: normal (N), $CCl_4$ control (C), $CCl_4$ plus Paecilomyces japonica (CPJ) (3%, w/w), $CCl_4$ plus C. militaris (CCM) (3%, w/w), and $CCl_4$ plus cordycepin-increased C. militaris ($CCM{\alpha}$) (3%, w/w). The activities of the liver marker enzymes ALT, AST, and LDH and the levels of lipid peroxidation were increased in the $CCl_4$-treated groups, but these parameters were significantly decreased in the $CCM{\alpha}$ group. The TBARS content in the liver homogenate, microsome, and mitochondrial fractions of the C group was significantly elevated compared with the N group. However, in the $CCl_4$-treated groups, $CCM{\alpha}$ group was significantly lowered in the TBARS levels of hepatic homogenate and microsomal fractions. The C group showed a significant decrease in the levels of plasma and hepatic glutathione, whereas they were significantly increased in the $CCM{\alpha}$ group. Accordingly, cordycepin-increased C. militaris may be an ideal animal model for studying hepatoprotective effects.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.1
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• pp.84-95
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• 2001

Titanium is widely used in dentistry for its low density, high strength, fatigue resistance, corrosion resistance, and biocompatibility. But it has a tendency of surface damage under circumstance of friction and impact for its low hardness of the surface. Coating is one of methods fir increasing surface hardness. Its effect is to improve surface physical characteristics without change of titanium. Diamond-like carbon and titanium nitride are known for its high hardness of the surface. So that this study was aimed at the wear test and the cytotoxicity test of the commercially pure titanium and Ti-6Al-4V alloy which were deposited by diamond-like carbon film or titanium nitride film to acertain improvement of the surface hardness and the biocompatibility. A disk (25mm diameter, 2mm thickness) was made of commercially pure titanium and Ti-6Al-4V alloy and these substrates were deposited by diamond-like carbon film or titanium nitride film. Diamond-like carbon film was deposited by the method of radiofrequency plasma assisted chemical vapor deposition and titanium nitride film was deposited by the method of reactive arc ion plating. Then these substrates were tested about wear characteristics by the pin-on-disk type wear tester in which ruby ball was used as a wear causer under the load of 32N, The fracture cycles were measured by rotating the substrates until their films were fractured. The wear volume was measured after 150 cycles and 3,000 cycles using surface profiler. The cytotoxicity test was peformed by the method of the MTT assay. The results were as follows : 1. In the results of the wear volume test, commercially pure titanium and titanium alloy which were coated by diamond-like carbon film or titanium nitride aim had higher resistance against wear than the substrates which were not coated by any films (P<0.05). 2. In the results of the fracture cycle test and the wear volume test, diamond-like carbon film had higher resistance against wear than titanium nitride film (P<0.05). 3. In both coatings of diamond-like carbon aim and titanium nitride film, Ti-6Al-4V alloy had higher resistance against wear than commercially pure titanium (P<0.05) 4. In the results of the cytotoxicity test, diamond-like carbon film and titanium nitride film had little cytotoxicity as like commercially pure titanium or Ti-6Al-4V alloy (P>0.05).

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.531-542
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• 2016

This experiment was conducted to verify whether or not chronic consumption of liquor prepared with Gastrodiae rhizoma exhibits antioxidant activity in brain tissue of rats. In the experiment, male Sprague-Dawley rats were given a liquid diet containing 6% (GA6), 18% (GA18), and 36% (GA36) of total calories as liquor for 6 weeks. The control rats (GAC6, GAC18, GAC36) received an isocaloric diet containing Soju instead of liquor. Caloric intakes and body weight gains of the 36% groups were significantly lower than those of the 6% and 18% groups (p<0.05), whereas alcohol intakes were significantly high in the 36% group (p<0.05). MDA contents of plasma and brain showed a positive correlation with alcohol intakes of the liquor and Soju consuming groups. Especially, contents of MDA were significantly higher in the 18% and 36% groups than the 6% group (p<0.05). SOD activities of serum and brain were significantly highest in the 18% group, and they tended to be higher in the liquor consuming groups compared with the control group. Catalase activity of serum showed no significant changes in the three groups consuming liquor, and catalase activity of brain tissue significantly increased in the GA18 group compared with the control group (p<0.05). In the liquor consuming groups, TAC level of serum tended to be higher in the GA36 group compared with the control group (p<0.05). However, TAC level of brain tissue showed no significant changes between the liquor consuming and control groups. These results show that as alcohol intake increased by chronic administration of liquor and Soju, brain tissue of rats was damaged more due to oxidative stress. However, a liquid diet containing 18% of total calories as liquor instead of Soju is expected to have a protective effect on brain damage induced by oxidative stress.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.406-406
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• 2010

일반적으로, 나노스케일의 MOS 소자에서는 게이트 절연체 두께가 감소함에 따라 tunneling effect의 증가로 인해 PID (plasma induced damage)로 인한 소자 특성 저하 현상을 감소하는 추세로 알려져 있다. 하지만 요즘 많이 사용되고 있는 high-k 게이트 절연체의 경우에는 오히려 더 많은 charge들이 trapping 되면서 PID가 오히려 더 심각해지는 현상이 나타나고 있다. 이러한 high-k 게이트 식각 시 현재는 주로 Hf-based wet etch나 dry etch가 사용되고 있지만 gate edge 영역에서 high-k 게이트 절연체의 undercut 현상이나 PID에 의한 소자특성 저하가 보고되고 있다. 본 연구에서는 이에 차세대 MOS 소자의 gate stack 구조중 issue화 되고 있는 metal gate 층과 gate dielectric 층의 식각공정에 각각 중성빔 식각과 중성빔 원자층 식각을 적용하여 전기적 손상 없이 원자레벨의 정확한 식각 조절을 해줄 수 있는 새로운 two step 식각 공정에 대한 연구를 진행하였다. 먼저 TiN metal gate 층의 식각을 위해 HBr과 $Cl_2$ 혼합가스를 사용한 중성빔 식각기술을 적용하여 100 eV 이하의 에너지 조건에서 하부층인 $HfO_2$와 거의 무한대의 식각 선택비를 얻었다. 하지만 100 eV 조건에서는 낮은 에너지에 의한 빔 스케터링으로 실제 패턴 식각시 etch foot이 발생되는 현상이 관찰되었으며, 이를 해결하기 위하여 먼저 높은 에너지로 식각을 진행하고 $HfO_2$와의 계면 근처에서 100 eV로 식각을 해주는 two step 방법을 사용하였다. 그 결과 anistropic 하고 하부층에 etch stop된 식각 형상을 관찰할 수 있었다. 다음으로 3.5nm의 매우 얇은 $HfO_2$ gate dielectric 층의 정확한 식각 깊이 조절을 위해 $BCl_3$와 Ar 가스를 이용한 중성빔 원자층 식각기술을 적용하여 $1.2\;{\AA}$/cycle의 단일막 식각 조건을 확립하고 약 30 cycle 공정시 3.5nm 두께의 $HfO_2$ 층이 완벽히 제거됨을 관찰할 수 있었다. 뿐만 아니라, vertical 한 식각 형상 및 향상된 표면 roughness를 transmission electron microscope(TEM)과 atomic force microscope (AFM)으로 관찰할 수 있었다. 이러한 중성빔 식각과 중성빔 원자층 식각기술이 결합된 새로운 gate recess 공정을 실제 MOSFET 소자에 적용하여 기존 식각 방법으로 제작된 소자 결과를 비교해 본 결과 gate leakage current가 약 one order 정도 개선되었음을 확인할 수 있었다.