점토광물을 이용한 산소환원의 전기화학적 촉매성에 관한 연구

오성훈,황진연,심윤보,이효민,윤지해 한국광물학회 2005 광물과 암석 (J.Miner.Soc.Korea) Vol.18 No.1

몇 가지 점토광물과 메틸바이올로젠 또는 메틸렌블루를 함유시킨 점토수식전극을 이용하여 산소환원에 대한 전기화학적 촉매성을 검토하였다. 점토광물로는 Na-몬모릴로나이트, Ca-몬모릴로나이트, 카오리나이트를 사용하였다. 점토수식전극은 유리탄소전극 표면에 점토 현탁액을 입히고 메틸바이올로젠을 흡착시킨 것을 사용하였으며, 전기화학적 산소환원의 정도는 순환 전압전류(cyclic voltammetry)으로 측정하였다. 실험결과, 다른 점토시료에 비하여 Na-몬모릴로나이트가 메틸바이올로젠의 흡착효과가 가장 크게 나타났고, 메틸바이올로젠을 흡착시킨 점토수식전극이 산소환원에 대한 촉매성이 월등히 우수하였다. 즉 촉매산소환원 피크가 242.6 ㎷ 만큼 +방향으로 이동하였다. 메틸바이올로젠을 흡착시킨 점토수식전극이 메틸렌블루를 흡착시킨 점토수식전극보다 산소환원에 대한 촉매성이 더 높게 나타났다. Ca-몬모릴로나이트의 경우는 변화가 없었으나 Na-몬모릴로나이트의 구조는 메틸바이올로젠의 흡착으로 변화되었다. 메틸바이올로젠- Na-몬모릴로나이트 점토수식전극을 현탁액의 점토 농도가 약 0.87 g/10 mL이고, 메틸바이올로젠의 수용액의 농도가 대략 2.5 mM일 때 산소환원 촉매 효과가 가장 탁월하였다. 지지전해질의 pH에 따른 점토수식 전극의 산소 환원 촉매성은 중성의 pH 범위(6.3과 8.3)에서보다 산성인 pH 3.7과 알칼리성인 pH12.7에서 월등히 크게 나타났다. The electrocatalytic reduction of O₂ was investigated with methyl viologen and methylene blue incorporated clay-modified electrodes. Clay suspensions were prepared with Namontmorillonite, Ca-montmorillonite, and kaolinite. The methyl viologen-clay modified electrodes were made by coating clay suspensions adsorbing methyl viologen on a glassy carbon electrode. Cyclic voltammetry were performed in aqueous media to investigate the electrocatalytic property of the modified electrode in reducing O₂. A Na-montmorillonite modified electrode showed the greatest adsorption capacity for methyl viologen. The modified electrode made of Na-montmorillonite suspension of 0.87 g/l0 mL and a 2.5 mM of methyl viologen solution showed the most effective electrocatalytic property, where the catalytic reduction potential was shifted by 242.6 ㎷ toward the positive potential. The electrocatalytic ability was more significant in acidic (pH=3.7) and alkaline (pH=12.7) media than the neutral pH range (6.3~8.3). The methyl viologen-Na-montmorillonite modified electrode had the good reproducibility and maintain the electrocatalytic property over 20 times reuse.

Experimental Study on Behavior of Concrete Slab Strengthened by Carbon Fiber Sheets

Shim, Jae-Soo,Hwang, Eui-Seung,Park, Yoon-Sik 경희대학교 산학협력기술연구원 1998 산학협력기술연구논문집 Vol.4 No.-

최근 국내에서는 여러 교량 및 건물의 붕괴로 인하여 구조물의 유지관리 특히 보수 및 보강에 과한 관심이 커지고 있다. 교량 구조물의 경우에 바닥판에 대하여서는 강판접착 또는 바닥판 두께 증가 등에 여러 가지 보강공법이 사용되고 있다. 최근에 탄소유리 섬유를 쉬트의 형태로 가공한 것이 개발되었는데 이러한 탄소섬유 쉬트는 높은 인장강도를 갖으며 경량이고 부식할 염려가 없다는 장점을 갖고 있다. 또한 유연하므로 다루기 쉽고 곡면에 적용할 수 있다. 본 연구의 목적은 실험을 통하여 탄소섬유로 보강된 콘크리트 바닥판의 거동을 조사하는 것이다. 이를 위해 6개의 콘크리크바닥판 시험체가 제작되었으며 다양한 방법으로 보강된 시험체를 파괴시까지 가력하여 그 거동을 분석하였으면 시방서상의 이론치와 비교하였다.

결핵균 및 기타 3종 Mycobacteria 의 파쇄추출항원과 교차반응하는 폐결핵환자의 항체분석

황응수,조명제,심영수,김익상,차창용,국윤호,이승훈,한용철,배길한,김상재 대한미생물학회 1985 大韓微生物學會誌 Vol.20 No.1

It is important to discriminate between tuberculosis and tuberculosis-like disease by Mycobacteria other than tuberculosis in the serodiagnosis of tuberculosis. But because common antigens share among Mycobacteria, their antigenicities to human are similar. Therefore degree of cross-reactivity of anti-body in the sera of patients with tuberculosis between M. tuberculosis and Mycobacteria other than tu- berculosis should be checked to increase the specificity in the serodiagnosis of tuberculosis. The activity levels of IgG antibody in the sera of 106 patients confirmed as active pulmonary tuber-culosis and 30 normal healthy control person to the pressate extract antigen (TE, BE, AE, and FE antigen) from M. tuberculosis, M. bovis, M. avium, and M. fortuitum were measured by enzyme-linked immunosorbe:nt assay and the crossreactivity of IgG antibody with mycobacterial species was analysed. The results were as follows; 1. The activity level (O.D. at 492nm) of 1gG to TE antigen in sera of patients with pulmonary tuber- culosis was 0.228±0.167 in minimal tuberculosis; moderately advanced, 0.556±0.616; far advanced, 1.116±0.651 and 0.315±0.245 in miliary tuberculosis. 2. The actiivity level (O.D. at 492nm) of IgG to BE antigen in sera of patients with pulmonary tu-berculosis was 0.190+0.162 in minima1 tuberculosis; moderately advanced, 0.337+0.361; far advanced, 0.713+0.460 and 0.204±0.162 in miliary tuberculosis. 3. The activity level (O.D. at 492nm) of IgG to AE antigen in sera of patients with pulmonary tu-berculosis was 0.165±0.114 in minimal tuberculosis; moderately advanced, 0.392±0.494; far adven- ced, 0.751±0.512 and 0.2330.191 in miliary tuberculosis. 4. The activity level (O.D. at 492nm) of IgG to FE antigen in sera of patients with pulmonary tub- erculosis was 0.280±0.227 in minimal tuberculosis; moderately advanced, 0.460±0.564; far advan- ced, 0.845±0.573 and 0.257±0.103 in miliary tuberculosis. 5. The activity level (O.D. at 492nm) of IgG in sera of healthy control person was 0.126±0.084 to TE antigen, 0.105±0.041to BE antigen, 0.103±0.052 to AE antigen, and 0.095±0.061 to FE antigen. 6. Degree of correlation(r) in activity level of IgG between TE antigen and BE antigen was 0.905; between TE antigen and AE antigen, 0.760; between TE antigen and FE antigen, 0.790, and be- tween AE antigen and FE antigen,0.945. 7. As O.D. above 0.200 was determined positive for the serodiagnosis of pulmonary tuberculosis, the sensitivity and specificity in ELISA using TE antigen were 80% and 87% respectively, whereas in the case of using BE antigen, 66% and 100%; in the case of using AE antigen, 62% and 100 %, and in the case of using FE antigen, 72% and 93%, respecitively.

Effect of electrode pattern on light emission distribution in InGaN/GaN light emitting diode

Hwang, Sungmin,Yoon, Joosun,Shim, Jongin,Yoo, Kyungyul WILEY-VCH Verlag 2008 Physica status solidi. PSS. C, Current topics in s Vol.5 No.6

<P>The effect of geometrical electrode pattern on the blue InGaN/GaN multi-quantum well (MQW) light emitting diode (LED) devices is investigated both theoretically and experimentally. A 3-dimensional circuit model of an LED is constructed and then the corresponding circuit parameters are extracted. Circuit parameters of an LED consist of the resistances of the metallic film and epitaxial layer, and intrinsic diodes representing the light-emitting active region. Both the transmission line model (TLM) and current-voltage (I-V) characteristics of LED are employed to extract circuit parameters experimentally. These circuit parameters are then applied to the circuit model to generate light emission patterns in a top-surface emitting-type LED. Experiment results verify that the emitting light distribution from fabricated LED coincides reasonably well with the theoretical results. This makes it possible to design an LED theoretically and predict its actual properties. The LED structure proposed using the model is shown to exhibit not only good light uniformity, but also higher light output power and lower voltage drop. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

Generation of Functional Dopamine Neurons from Neural Precursor Cells Isolated from the Subventricular Zone and White Matter of the Adult Rat Brain Using Nurr1 Overexpression

Shim, Jae-Won,Park, Chang-Hwan,Bae, Yong-Chul,Bae, Jin-Young,Chung, Seungsoo,Chang, Mi-Yoon,Koh, Hyun-Chul,Lee, Hyun-Seob,Hwang, Se-Jin,Lee, Ki-Hwan,Lee, Yong-Sung,Choi, Cha-Yong,Lee, Sang-Hun Wiley (John WileySons) 2007 Stem Cells Vol.25 No.5

<P>Neural precursor (NP) cells from adult mammalian brains can be isolated, expanded in vitro, and potentially used as cell replacement source material for treatment of intractable brain disorders. Reduced ethical concerns, lack of teratoma formation, and possible ex vivo autologous transplantation are critical advantages to using adult NP donor cells over cells from fetal brain tissue or embryonic stem cells. However, the usage of adult NP cells is limited by the ability to induce specific neurochemical phenotypes in these cells. Here, we demonstrate induction of a dopaminergic phenotype in NP cells isolated from the subventricular zone (SVZ) and white matter of rodent adult brains using overexpression of the nuclear receptor Nurr1 in vitro. Forced expression of Nurr1, a transcriptional factor specific to midbrain dopamine (DA) neuron development, caused in the adult cells an acquisition of the DA neurotransmitter phenotype and sufficient differentiation toward morphologically, phenotypically, and ultrastructurally mature DA neurons. Co-expression of neurogenic factor Mash1 and treatment with neurogenic cytokines brain-derived neurotrophic factor and neurotrophin-3 greatly enhanced Nurr1-induced DA neuron yield. The Nurr1-induced DA neurons demonstrated in vitro presynaptic DA neuronal functionality, releasing DA neurotransmitter in response to depolarization stimuli and specific DA reuptake. Furthermore, Nurr1-engineered adult SVZ NP cells survived, integrated, and differentiated into DA neurons in vivo that can reverse the behavioral deficit in the host striatum of parkinsonian rats. These findings open the possibility for the use of precursor cells from adult brains as a cell source for neuronal replacement treatment of Parkinson disease. Disclosure of potential conflicts of interest is found at the end of this article.</P>

Licochalcone D Inhibits Skin Epidermal Cells Transformation through the Regulation of AKT Signaling Pathways

Hwang Sun-Young,Wi Kwanhwan,Yoon Goo,Lee Cheol-Jung,Lee Soong-In,Jung Jong-gil,Jeong Hyun-Woo,Kim Jeong-Sang,Choi Chan-Heon,Na Chang-Su,Shim Jung-Hyun,Lee Mee-Hyun 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.6

Cell transformation induced by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) is a critical event in cancer initiation and progression, and understanding the underlying mechanisms is essential for the development of new therapeutic strategies. Licorice extract contains various bioactive compounds, which have been reported to have anticancer and anti-inflammatory effects. This study investigated the cancer preventive efficacy of licochalcone D (LicoD), a chalcone derivative in licorice extract, in EGF and TPA-induced transformed skin keratinocyte cells. LicoD effectively suppressed EGF-induced cell proliferation and anchorage-independent colony growth. EGF and TPA promoted the S phase of cell cycle, while LicoD treatment caused G1 phase arrest and down-regulated cyclin D1 and up-regulated p21 expression associated with the G1 phase. LicoD also induced apoptosis and increased apoptosis-related proteins such as cleaved-caspase-3, cleaved-caspase-7, and Bax (Bcl- 2-associated X protein). We further investigated the effect of LicoD on the AKT signaling pathway involved in various cellular processes and found decreased p-AKT, p-GSK3β, and p-NFκB expression. Treatment with MK-2206, an AKT pharmacological inhibitor, suppressed EGF-induced cell proliferation and transformed colony growth. In conclusion, this study demonstrated the potential of LicoD as a preventive agent for skin carcinogenesis.

EFFECT OF PURIFIED ALGINATE MICROCAPSULES ON THE REGENERATION OF CHONDROCYTES

Hwang, Ji Hye,Kim, On You,Kim, A Ram,Bae, Ji Yeon,Jeong, Su Mi,Shim, Jung Bo,Yoon, Kun Ho,Lee, Dongwon,Khang, Gilson National Taiwan University 2012 Biomedical engineering Vol.24 No.3

<P> Adult articular cartilage tissue has poor capability of self-repair. Therefore, a variety of tissue engineering approaches are motivated by the clinical need for articular repair. Alginate has been used as a biomaterial for cartilage regeneration. The alginate is a natural polymer that is extracted from seaweeds and purification. However, the main drawback is the immune rejection in vivo. To overcome this problem, we have developed the biocompability of alginate using modified Korbutt method. After alginate was purified, purified alginate microcapsules were used in cartilage regeneration. Chondrocytes were seeded in purified and nonpurified alginate microcapsules, and then cell viability, proliferation and phenotype were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. Reverse transcriptase-polymerase chain reaction (RT-PCR) was conducted to confirm mRNA expression on collagen type I and collagen type II for chondrocytes phenotype. Hematoxylin and eosin (H&E) and Safranin-O histological staining showed tissue growth at the interface during the first 10 days. In this study, chondrocytes in purified alginate microcapsules had higher cell viability, proliferation and more phenotype expression than those in nonpurified alginate microcapsules. The results suggest that the purified alginate microcapsule is useful for cartilage regeneration. </P>

Variations in carbon and nitrogen stable isotopes and in heavy metal contents of mariculture kelp Undaria pinnatifida in Gijang, southeastern Korea

Shim, JeongHee,Kim, Jeong Bae,Hwang, Dong-Woon,Choi, Hee-Gu,Lee, Yoon The Korean Society of Phycology 2017 ALGAE Vol.32 No.4

Korean mariculture Undaria pinnatifida was collected during the months of January, February, March, and December of 2010, as well as from January of 2011 to investigate the changes in the carbon and nitrogen stable isotope ratios (${\delta}^{13}C$ and ${\delta}^{15}N$) and heavy metal with respect to it growth and to identify the factors that influence such changes. The blades of U. pinnatifida showed ${\delta}^{13}C$ and ${\delta}^{15}N$ in the range (mean) of -13.11 to -19.42‰ (-16.93‰) and 2.99 to 7.57‰ (4.71‰), respectively. Among samples with the same grow-out period, those that weighed more tended to have higher ${\delta}^{13}C$ suggesting a close association between the carbon isotope ratio and growth rate of U. pinnatifida. Indeed, we found a very high positive linear correlation between the monthly average ${\delta}^{13}C$ and the absolute growth rate in weight ($r^2=0.89$). Nitrogen isotope ratio tended to be relatively lower when nitrogen content in the blade was higher, probably due to the strengthening of isotope fractionation stemming from plenty of nitrogen in the surrounding environment. In fact, a negative linear correlation was observed with the nitrate concentration in the nearby seawaters ($r^2=0.83$). Concentrations of Cu, Cd, Pb, Cr, Hg, and Fe in the blades showed a rapid decrease in their concentration per unit weight in the more mature U. pinnatifida. Specifically, compared to adult samples, Cu, Hg, and Pb were concentrated by 30, 55, and 73 folds, respectively, in the young blades. Therefore, U. pinnatifida tissue ${\delta}^{13}C$ is as an indirect indicator of its growth rate, while ${\delta}^{15}N$ values and heavy metal concentrations serve as tracers that reflect the environmental characteristics.

Relative validities of 3-day food records and the food frequency questionnaire

Yoon Jung Yang,Mi Kyung Kim,Se Hee Hwang,Younjhin Ahn,Jae Eun Shim,Dong Hyun Kim 한국영양학회 2010 Nutrition Research and Practice Vol.4 No.2

The food frequency questionnaire (FFQ) has been used as an important dietary assessment tool in epidemiologic studies, but the usefulness of the FFQ has been debated in recent years. This study was performed to evaluate the relative validities of 3-day food records and the semi-quantitative FFQ. A total of 124 subjects finished 3-day food records (FRs) during each of the four seasons, as well as the FFQ from December 2002 to May 2004. The FFQ was a food based semi-quantitative FFQ including 103 items. Three-day FRs from each season and a randomly selected season were compared with the remaining 9-day FRs. The remaining 9-day FRs, as a reference measurement, were also compared with the FFQ. Pearson’s correlation coefficients between the 3-day FRs and the 9-day FRs were between 0.14 and 0.56. Pearson’s correlation coefficients between the FFQ and the 9-day FRs ranged between 0.07 and 0.41. Average proportions of classification into the same quartiles, adjacent quartiles, and distant quartiles between the 3-day FRs and the 9-day FRs were 35.8%, 40.5%, and 5.2%, respectively. On average, the proportions of classification into the same quartiles, adjacent quartiles, and distant quartiles between the FFQ and the 9-day FRs were 31.1%, 39.4%, and 6.9%, respectively. Three-day FRs showed higher correlations and higher agreement proportions of quartile classification with the 9-day FRs than did the FFQ, but both relative validities of 3-day FRs and the FFQ appear to be acceptable as dietary assessment tools. Further studies for validating food intake by reliable biomarkers are necessary.

Proteomics Comparison of Longissimus Muscle between Hanwoo and Holstein Cattle

Shim, Kwan-Seob,Park, Garng-Hee,Hwang, In-Ho,Yoon, Chang,Na, Chong-Sam,Jung, Hyun-Jung,Choe, Ho-Sung Korean Society for Food Science of Animal Resource 2010 한국축산식품학회지 Vol.30 No.3

This study was conducted to compare proteins expressed in M. longissimus from Hanwoo and Holstein steers immediately after slaughter. Two-dimensional electrophoresis (2DE)/LC-MS/MS analysis revealed that the total number of detectable protein spots from longissimus muscle tissues was slightly higher in Hanwoo ($575{\pm}65$) than Holstein ($534{\pm}13$) steers, but that these numbers were not statistically significant due to large variation between replicates. A total of twelve protein spots did not match between sample groups, eight of which were expressed in the Hanwoo sample and four that were expressed in the Holstein sample. The protein spots detected in the Hanwoo sample included smooth muscle and non-muscle myosin alkali light chain 6B isomers, ${\alpha}B$ crystallin isomers, hemoglobin ${\beta}$-A chains, slow myosin heavy chains, and slow skeletal muscle troponin T chains. Collectively, these proteins are a class of slow-twitch muscle fiber and mirror that Hanwoo muscle tissue sampled for the current study contained more slow-twitch muscle fibers than Holstein one. Conversely, proteins detected from the Holstein sample included ankyrin repeat domain 2 and creatin kinase isomers. Given that creatin kinase isomers are related to the fast-twitch muscle, these results likely indicate that Holstein muscle tissue sampled for the current study contained more fast-twitch muscle fibers than Hanwoo beef.