• Korean Journal of Oriental Medicine
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• v.1 no.1
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• pp.509-520
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• 1995

The effect of water extract of antler on serum level of female hormones was investigated in ovariectemized rats. Sprague-Dawley rats were ovariectomized(ox). After a further 40 days the animals were administrated with water extract of antler (625mg/kg daily) for 10, 20 and 30 days, respectively. Serum level of estradiol, progesterone, leutenizing hormone and follicle stimulating hormone were measured. Significant increase of serum estradiol level was elicited at 20 and 30 days after treatment with water extract of antler, respectively, Associated with the increase of serum estradiol level, there was a concomitant decrease in serum follicle stimulating hormone level. Serum progesterone level was also significantly increased at 30 days after treatment with water extract of antler. Although serum leutenizing hormone level of ox rats treated with water extract of anther was slightly lower than that of untreated ox rats, the decrease was not significant.

• Journal of Nutrition and Health
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• v.36 no.9
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• pp.908-917
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• 2003

It has been proposed that oxidative modification of LDL (oxLDL) plays a significant role in the pathogenicity of atherogenesis. We tested the hypothesis that chitin and chitosan may function as antioxidants with respect to 0.1 mg cholesterol/ml LDL incubated with 5 $\mu$ M Cu$^2$$^{+}$alone or in the P338Dl mouse macrophage system using L-ascorbic acid as a standard classical antioxidant. The degree of oxLDL formation was ascertained by the relative electrophoretic mobility (rEM) in the combination of thiobarbituric acid reactive substances (TBARS) levels, and the cytotoxicity of oxLDL was detected by macrophage viability. The oxLDL uptake and foam cell formation of macrophages were measured by Oil Red O staining. Incubation with Cu$^2$$^{+}$and macrophages increased rEM of LDL and stimulated TBARS formation. Culture of macrophages with LDL in the presence 5 $\mu$ M Cu$^2$$^{+}$induced macrophage death. In cell-free system 200 $\mu$g/ml water-soluble chitosan and chitosan-oligosaccharide blocked oxLDL formation. Water-soluble chitosan and chitosan-oligosaccharide blocked oxLDL formation near-completely relative to L-ascorbic acid, whereas water-soluble chitin and chitin-oligosaccharide had no measurable antioxidant effect. In macrophage system water-soluble chitosan and chitosan-oligosaccharide blocked oxidation of LDL with a significant increase in cell viability, and decreased TBARS in medium. As for the inhibitory effect on macrophage foam cell formation, chitosan and its oligosaccharide, but not watersoluble chitin, revealed the effectiveness. The endothelial expression of lectin-like oxLDL receptor-1 (LOX-1) was tested by Western blot analysis, and chitosan, chitosan-oligosaccharide and chitin-oligosaccharide blocked LOX-1 expression. These results indicate that water-soluble chitosan and its oligosaccharide showed the inhibitory effect on Cu$^2$$^{+}$-induced LDL oxidation of macrophages, and chitosan, chitosan-oligosaccharide and chitin-oligosaccharide had blocking effect on oxLDL receptor expression in the human umbilical vein endothelial system. Thus, water-soluble chitosan and its oligosaccharides possess anti-atherogenic potentials possibly through the inhibition of macrophage LDL oxidation or endothelial oxLDL receptor expression depending on chemical types.l types.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.59-66
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• 2008

This study was undertaken to evaluate the antioxidant potential of A. lanata on oxalate mediated free radical toxicity in ethylene glycol induced calcium oxalate urolithic rats. Calcium oxalate (CaOX) stone was induced by 0.75% ethylene glycol in drinking water for 28 days. From $29^{th}$ day onwards, the CaOX urolithic rats were treated with A. lanata aqueous suspension (2,000 mg/kg body weight/dose/day) orally for another 28 days. At the end of experimental periods the animals were sacrificed, samples were collected and analyzed the lipid peroxidation product, protein oxidation product, enzymatic and non-enzymatic antioxidants in normal and experimental groups. Lipid peroxidation and protein oxidation products were significantly elevated while enzymatic and non-enzymatic antioxidant levels were significantly decreased in ethylene glycol induced CaOX urolithic rats when compared with control rats. The above alterations were reverted to near control in rats treated with aqueous suspension of A. lanata. This study suggests that A. lanata could prevent the free radical formation from calcium oxalate urolithiasis in rats and protecting the renal cells from oxidative injury.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.231-231
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• 2013

ZnO은 hexagonal wurtzite 구조를 갖는 직접 천이형 화합물 반도체로서, 상온에서 3.37 eV 정도의 wide band gap energy를 가지고 있으며, 60 meV의 큰 엑시톤 결합 에너지(exciton binding energy)를 갖는다. 또한 동종 기판이 존재하고 열, 화학적으로 안정한 상태이며 습식 식각이 가능한 장점으로 인해 각광받고 있다. 또한, ZnO 박막은 우수한 전기 전도성을 나타내며 광학적 투명도가 우수하기 때문에 투명전극으로 많이 이용되어 왔고, 태양 전지(solar cell), 가스 센서, 압전소자 등 많은 분야에서 사용되고 있다. 이와 같은 ZnO박막을 안정적인 쇼트키 다이오드 특성을 얻기 위해서는 쇼트키 배리어 장벽의 형성이 필수적이다. Mg을 ZnO에 첨가하여 MgZnO 박막을 형성할 경우, 금속의 일함수와 MgZnO의 전자친화력 차이가 증가하여 더 큰 쇼트키 장벽 형성이 가능하며, 금속의 일함수가 큰 물질을 사용해야 한다. 또한, 박막의 결함이 적은 박막을 형성해야 하는 에피탁셜 박막이 필요하다. SiC는 높은 포화 전자 드리프트 속도(${\sim}2.7{\times}107$ cm/s), 높은 절연 파괴전압(~3 MV/cm)과 높은 열전도율(~5.0W/cm) 특징을 가지고 있으며, MgZnO/Al2O3의 격자 불일치는 ~19%인 반면에 MgZnO/SiC의 격자 불일치는 ~6%를 가진다. 금속의 일함수가 큰 Ag 금속은 열처리가 될 경우 AgOx가 될 경우 더욱 안정적인 쇼트키 장벽을 형성될 수 있을 것으로 판단된다. 본 연구에서는 쇼트키 접합을 형성하기 위해 금속의 일함수가 큰 Ag 금속을 사용하였으며, Al2O3 기판과 6H-SiC 기판위에 MgZnO(30 at.%) 박막을 증착하였다. 증착 후에 Ag를 증착 한 뒤 급속 열처리를 하였다. 열처리된 MgZnO의 경우 열처리 하지않은 소자보다 약 $10^5$ 이상의 우수한 on/off 특성을 보였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.150-150
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• 2012

본 연구는 1차원 나노 구조의 합성과 기초적 분석에 관한 연구로써 특히 무기 산화물 나노재료를 그 대상으로 하였다. 내용으로는 첫째, 1차원 코어 나노와이어의 합성을 하였고 Thermal evaporation, substrate의 가열, 그리고 MOCVD 를 사용한 결과들을 나열한다. 둘째, 코어-쉘 나노와이어를 제작하기 위하여 특히 쉘층의 제작방법을 연구하였는데 PECVD, ALD, 그리고 sputtering에 의한 결과들을 나열하고 간단히 설명한다. Thermal evaporation에 의한 1차원 나노와이어 합성의 경우는 MgO의 예를 들었는데 MgO 나노와이어는 Au가 증착된 기판을 열처리하여 Au dot를 형성하고 이의 morphology를 조절하여 최적의 나노와이어 합성조건을 선정하였다. 이로써 기판 morphology가 나노선의 성장및 형상에 영향을 준다는 사실을 알게 되었다. 이 사실은 In2O3기판을 사용하고 이의 표면거칠기를 열처리로 조절하므로써 역시 나노와이어의 성장을 촉진하는 방법을 찾아내었다. 또한 thermal evaporation공법은 source분말의 선택에 따라 다양한 소재를 제작가능하다는 결과를 제시하였다. 예를 들면 SiOx 층이 precoating된 chamber내에서 MgO 나노선을 합성하는 것과 동일한 조건으로 실험을 진행하면 Mg2SiO4 나노와이어가 형성된 것을 확인하였다. 또한 Sn과 MgB2 분말을 함께 적용할 경우 Sn tip을 가진 MgO 나노와이어를 얻을 수 있었다. 이는 Sn이 동시에 촉매의 역할을 하였기 때문일 것으로 추정된다. 한편 Sn과 Bi 혼합분말을 적용한 경우 Bi2Sn2O7 신소재 tip을 포함한 SnO2 나노와이어를 얻을 수 있었다. 이 경우 Bi원자가 적절한 촉매의 역할을 수행한 것으로 사료된다. Substrate의 가열공법에서는 Si wafer상에 각종 금속 즉 Au, Ag, Cu, Co, Mo, W, Pt, Pd등 초박막을 DC sputter 로 형성한후 annealing하는 기술을 사용하였다. 특기할 만한 것은 Co를 사용한 경우 나노와이어의 spring구조를 얻을 수 있었다는 점이다. MOCVD에 의하여는 Ga2O3및 Bi2O3 나노와이어를 비교적 저온에서 합성하였고 In2O3의 경우는 독특한 나노구조를 형성하였고 이의 결정학적 특성에 대하여 조사하였다.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.697-706
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• 2002

Authigenic siderite grains, ranging 100 to 250-${\mu}$m in diameter, are abundant in an about 8,600-year-old sediment layer in Namyang Bay, west coast of Korea. The siderites exhibit the aggregated spherulitic morphology with well-developed rhombs on the grain surfaces. They consist mostly of FeCO$_3$ (average, 65%) and MnCO$_3$ (average, 22%) with low Mg/Ca ratio (less than 0.4) in their bulk composition. A series of compositional ternary discrimination diagrams, together with high Mn and low Mg contents, show that only meteoric porewater was involved in siderite precipitation, assuming that depositional environment of host sediment is an organic-rich freshwater system. Considering a series of results such as radiocarbon age, authigenic Mn-rich siderite and lithological features, siderite-hosting sediment (unit Tl) is interpreted as freshwater swamp or bog deposition, infilling the topographic depressions that locally existed before the formation of mid-to-late Holocene tidal deposits. Center-to-margin compositional variation within individual grain is very systematic; Mn and Ca decrease towards the margin of a siderite grain, while Fe and Mg increase. It suggests that the spherulitic siderites were precipitated in this sedimentary layer in a series during the early diagenesis of MnOx-FeOx reduction under steady-state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.30-31
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• 2006

We have fabricated SmBCO coated conductor on IBAD-MgO substrates using unique co-evaporation method. The batch type co-deposition system was specially designed and named as EDDC(evaporation using drum m dual chamber) that is possible to deposit superconducting layer with different composition ratio at low temperature of $700^{\circ}C$. In this study, we have investigated the influence of SmBCO phase composition and texture of IBAD-MgO template on the critical current density. We have changed the deposition rates of Sm, Ba and Cu during co-evaporation to examine the optimal composition ratio shown better critical current density. The composition ratio and surface morphology of SmBCO coated conductors were analyzed by the EDX and SEM, respectively. A higher critical current density was measured at superconducting phase composition ratio of Ba deficiency, Sm or Cu rich compared to the Sm1Ba2Cu3Ox stoichiometry.

• Journal of Nutrition and Health
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• v.38 no.1
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• pp.67-75
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• 2005

This study was performed to examine the change of lipid metabolism and immune function caused by antioxidant material in hypercholesterolemic elderly women (serum total cholesterol $\geq$200 mg/dI). The subjects were 51 elderly women aged over 60 yrs. They were divided into antioxidant nutrients complex group (n = 25) and spirulina group (n= 26). Antioxidant nutrients complex (1 capsule/day) and spirulina (7.5 mg/day) were used for intervention for 8weeks. All the subjects were fully informed the purpose of study and gave written consents to participate in this study. Dietary intakes, anthropometric indices and blood assessment for lipid, immune function and antioxidant status were measured before and after supplementation. Either antioxidant nutrients complex or spirulina supplementation for 8weeks resulted in improved antioxidant status evidence by increased TAS (total antioxidant status) and decreased TB-ARS (thiobarbituric acid reactive substance) . This intervention led to decreased serum levels of total cholesterol, LDL-cholesterol, oxLDL, apolipoprotein B, IL-6 and IL-6 production by peripheral blood lymphocyte. In conclusion, the lipid profiles, immune function and antioxidant capacity were improved after either antioxidant nutrient complex or spirulina supplementation for hypercholesterolemic women. Therefore, improving antioxidant status using supplemen-tation could provide means of controlling cardiovascular disease in Korean elderly people.

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.328-332
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• 2008

This research was about T-N removal efficiency of oxic reactor in which fixed media submerged from Membrane BNR(An+Ax+Ox) process. This experiment was implemented by using fixed media and changing DO concentration in the oxic reactor. Nitrification efficiencies of all modes were more than 98%. When no media was in the oxic reactor, T-N removal efficiency was only 47.4%, while it were shown from 60.3% to 67.4% with packed media, which indicated improved efficiency of 27~42%. The removal efficiencies of TCOD and BOD were more than 89%, 98% respectively, which could satisfy the guideline of advanced sewage reclamation by Department of Environment. When DO concentration in the packed oxic-media tank was 0.5~1.0 mg/L, T-N removal efficiency was low, which resulted from insufficient nitrification in the oxic reactor. Therefore, DO concentration of bulk solution needs to be kept more than 1.0 mg/L to induce higher nitrification efficiency in the reactor in which media was submerged. Also, the selection of DO concentration is important to prevent media from being clogged.

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.245-249
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• 1994

NaMg[$Cr(C_2O_4)_3]{\cdot}10H_2O$ crystallizes in the trigonal space group P$\bar{3}$c1, with a=b= 16.969(3), c=12.521(3) ${\AA}$, ${\alpha}={\beta}=90^{\circ},\;{\gamma}=120^{\circ},\;{\rho}=1.734 \;gcm^{-3},\;{\mu}=6.46\;cm^{-1}$, Z=6. Intensities for 1062 unique reflections were measured on a four-circle diffractometer with Mo K${\alpha}$ radiation (${\lambda}=0.71069\;{\AA}$). The structure was solved by direct methods and refined to a final ${\omega}$R value of 0.084. X-ray crystal structure showed that magnesium ion appears to be occupied over two sites with the occupancy ratio of 2:1. The crystal possesses 10 water molecules instead of previously estimated 9 water molecules.