Nanogenerators: Fully Rollable Transparent Nanogenerators Based on Graphene Electrodes (Adv. Mater. 19/2010)

Choi, Dukhyun,Choi, Min-Yeol,Choi, Won Mook,Shin, Hyeon-Jin,Park, Hyun-Kyu,Seo, Ju-Seok,Park, Jongbong,Yoon, Seon-Mi,Chae, Seung Jin,Lee, Young Hee,Kim, Sang-Woo,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jo WILEY-VCH Verlag 2010 ADVANCED MATERIALS Vol.22 No.19

<B>Graphic Abstract</B> <P>The cover shows an image of fully rollable transparent nanogenerators synthesized using chemical vapor deposition grown large-scale graphene sheets as transparent electrodes and piezoelectric ZnO nanorod arrays. Sang-Woo Kim, Jae-Young Choi, and co-workers report on p. 2187 the electrical and structural stability of the nanogenerators, with excellent charge scavenging performance under external mechanical loads such as bending and rolling. This study shows that graphene-based nanogenerators are very promising for self-powered rollable transparent device applications. <img src='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content'> </P>

Mitochondrial dysfunction and calcium deregulation by the RanBP9-cofilin pathway

Roh, Seung-Eon,Woo, Jung A.,Lakshmana, Madepalli K.,Uhlar, Courtney,Ankala, Vinishaa,Boggess, Taylor,Liu, Tian,Hong, Yun-Hwa,Mook-Jung, Inhee,Kim, Sang Jeong,Kang, David E. The Federation of American Societies for Experimen 2013 The FASEB Journal Vol.27 No.12

<P>Mitochondrial dysfunction and synaptic damage are important features of Alzheimer's disease (AD) associated with amyloid β (Aβ) and tau. We reported previously that the scaffolding protein RanBP9, which is overall increased in brains of patients with AD and in mutant APP transgenic mice, simultaneously promotes Aβ generation and focal adhesion disruption by accelerating the endocytosis of APP and β1-integrin, respectively. Moreover, RanBP9 induces neurodegeneration <I>in vitro</I> and <I>in vivo</I> and mediates Aβ-induced neurotoxicity. Here we show in primary hippocampal neurons that RanBP9 potentiates Aβ-induced reactive oxygen species (ROS) overproduction, apoptosis, and calcium deregulation. Analyses of calcium-handling measures demonstrate that RanBP9 selectively delays the clearance of cytosolic Ca<SUP>2+</SUP> mediated by the mitochondrial calcium uniporter through a process involving the translocation of cofilin into mitochondria and oxidative mechanisms. Further, RanBP9 retards the anterograde axonal transport of mitochondria in primary neurons and decreases synaptic mitochondrial activity in brain. These data indicate that RanBP9, cofilin, and Aβ mimic and potentiate each other to produce mitochondrial dysfunction, ROS overproduction, and calcium deregulation, which leads to neurodegenerative changes reminiscent of those seen in AD.—Roh. S.-E., Woo, J. A., Lakshmana, M. K., Uhlar, C., Ankala, V., Boggess, T., Liu, T., Hong, Y.-H., Mook-Jung, I., Kim, S. J., Kang, D. E. Mitochondrial dysfunction and calcium deregulation by the RanBP9-cofilin pathway.</P>

Research of Effective Prevention against Leachiate Seepage from the Garbage Landfill at Sokdaedong , Pusan , Korea

(Haang Mook Kim),(Chang Woo Lee),(In Soo Kim),(Jin Yeon Hwang),(Sang Tai Kim),(Duk Mook Kim),(Sang Yong Cheong),(Sung Hyo Yoon),(Maeng Eon Park),(Chang Jeong Kim),(Chung Yeol Ryoo),(Sang Bae Kim),(Bye 자연사.미래환경학회(구.자연사환경학회) 1994 INTERNATIONAL SYMPOSIUM ON GEOLOGY , ENVIRONMENTS Vol.- No.-

Identification of Three Competitive Inhibitors for Membrane­Associated, $Mg^{2+}-Dependent$ and Neutral 60 kDa Sphingomyelinase Activity

Kim Seok Kyun,Jung Sang Mi,Ahn Kyong Hoon,Jeon Hyung Jun,Lee Dong Hun,Jung Kwang Mook,Jung Sung Yun,Kim Dae Kyong The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.8

Methanol extracts of domestic plants of Korea were evaluated as a potential inhibitor of neutral pH optimum and membrane-associated 60 kDa sphingomyelinase (N-SMase) activity. In this study, we partially purified N-SMase from bovine brain membranes using ammonium sulfate. It was purified approximately 163-fold by the sequential use of DE52, Butyl-Toyopearl, DEAE-Cellulose, and Phenyl-5PW column chromatographies. The purified N-SMase activity was assayed in the presence of the plant extracts of three hundreds species. Based on the in vitro assay, three plant extracts significantly inhibited the N-SMase activity in a time- and concentration-dependent manner. To further examine the inhibitory pattern, a Dixon plot was constructed for each of the plant extracts. The extracts of Abies nephrolepis, Acer tegmentosum, and Ginkgo biloba revealed a competitive inhibition with the inhibition constant (Ki) of $11.9 {\mu}g/mL,\;9.4{\mu}g/mL,\;and\;12.9{\mu}g/mL$, respectively. These extracts also inhibited in a dose-dependent manner the production of ceramide induced by serum deprivation in human neuroblastoma cell line SH-SY5Y.

Clinical meaning of pepsinogen test and Helicobacter pylori serology in the health check-up population in Korea

Kim, Hyun Young,Kim, Nayoung,Kang, Jung Mook,Park, Young Soo,Lee, Dong Ho,Kim, Yu Rim,Kim, Joo Sung,Jung, Hyun Chae,Song, In Sung Lippincott Williams Wilkins, Inc. 2009 European journal of gastroenterology & hepatology Vol.21 No.6

OBJECTIVE: This study was performed to assess the affects of age, sex, and Helicobacter pylori status on pepsinogen testing for atrophic gastritis and to establish the clinical implications of pepsinogen test results and H. pylori serology in a Korean population presenting for a health check-up. METHODS: Serum pepsinogen (PG) I and PG II, and H. pylori IgG were measured in 1485 adults. The PG values were analyzed based on age, sex, and H. pylori status, and the cutoff value for atrophic gastritis was determined. RESULTS: Serum PG I (sPGI) and sPGII were higher in H. pylori positive than in H. pylori negative individuals (sPGI, 56.3 vs. 42.2 μg/l, P<0.001; sPGII, 17.5 vs. 8.0 μg/l, P<0.001). The PG I/II ratio was lower in H. pylori positive than in H. pylori negative individuals (3.7 vs. 6.0, P<0.001). The sPGII and PG I/II ratio had a positive (r=0.132, P<0.001) and negative correlation with age (r=−0.229, P<0.001), respectively. Men had a higher sPGI (54.7 μg/l) than did women (48.4 μg/l) (P<0.001) but the PG I/II ratio was not statistically different and neither the atrophic gastritis. The PG I/II cutoff value for atrophic gastritis was 6.0 for H. pylori negative and 3.0 for H. pylori positive individuals. sPGI and sPGII were, however, not specific for atrophic gastritis. CONCLUSION: The H. pylori IgG status, age, and sex were associated with the serum PG levels. To increase the efficacy of the PG I/II ratio for the detection of atrophic gastritis, the cutoff value of the PG I/II ratio should be stratified according to the H. pylori IgG status in the Korean population presenting for a health check-up.

Structural Safety Test and Analysis of Type IP-2 Transport Packages with Bolted Lid Type and Thick Steel Plate for Radioactive Waste Drums in a NPP

Sang-Jin Lee,Dong-Hak Kim,Kyung-Ho Lee,Jeong-Mook Kim,Ki-Seog Seo 한국방사성폐기물학회 2007 방사성폐기물학회지 Vol.5 No.3

IP-2형 운반용기는 정상운반조건에서의 자유낙하시험 및 적층시험을 수행한 후에 운반내용물의 분산 및 유실이 없어야 하며 외부표면에서의 방사선량률이 20%이상 증가할 수 있는 차폐능력의 상실이 없어야 한다. 본 연구에서는 두꺼운 철판을 구조재로 사용하며 볼트체결방식의 뚜껑을 가진 IP-2형 운반용기에 대한 구조 안전성을 평가하기 위한 해석적인 방안을 제안하였다. 해석적인 방법을 통하여 원자력발전소에서 발생된 방사성폐기물 드럼을 폐기물 처리시설에서 임시저장고까지 운반하기 위한 두 종류의 IP-2형 방사성폐기물 운반용기에 대하여 자유낙하조건에서 운반내용물의 분산 및 유실과 차폐손실이 없음을 확인하였다. 자유낙하조건에서 운반내용물의 분산 및 유실을 평가하기 위하여 최대 볼트단면 평균응력값과 최대 뚜껑열림량을 볼트의 인장강도와 뚜껑부에 존재하는 단차와 비교 평가하였다. 또한 최대 차폐두께 감소량을 이용하여 차폐손실을 평가하였다. 자유낙하조건에 대한 동적충돌해석을 검증하고 구조 안전성을 시험적으로 평가하기 위하여 자유낙하시험을 다양한 방향으로 실시하였다. 자유낙하시험에서는 운반내용물의 분산 및 유실은 볼트체결방식의 뚜껑에서 볼트의 파손 및 플랜지의 변형 등을 검사하여 평가하였으며, 차폐손실은 초음파 두께 측정기를 이용한 차폐두께를 측정하여 평가하였다. 해석에 대한 검증을 위하여 시험에서 취득한 변형률과 가속도를 동일한 위치에서 얻어진 해석결과와 비교하였다. 해석결과는 시험결과에 비하여 보수적인 결과를 보여주므로 해석에서 입증한 IP-2형 방사성폐기물 운반용기의 안전성은 보수적인 결과이다. 마지막으로 유한요소해석을 통하여 적층조건에 대한 IP-2형 방사성폐기물 운반용기는 안전함을 입증하였다. 적층해석에서 차폐체의 응력은 항복응력에 비하여 1/3정도의 작은 값을 보였다. 두 종류의 IP-2형 방사성폐기물 운반용기는 정상운반조건에서의 자유낙하시험 및 적층시험에 대하여 안전함을 입증하였다. If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or dispersal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions. For the tests we examined the failure of bolts and the deformation of flange to evaluate a loss or dispersal of radioactive material and measured the shielding thickness using a ultrasonic thickness gauge to assess a loss of shielding integrity. The strains and accelerations acquired from tests were compared with those by analyses to verify the impact dynamic analysis. The analytic results were larger than the those of test so that the analysis showed the conservative results. Finally, we evaluated the safety of the type IP-2 transport package under the stacking test condition using a finite element analysis. Under the stacking test condition, the maximum Tresca stress of the shielding material was 1/3 of the yielding stress. Two kinds of a type IP-2 transport package were safe for the free drop test condition and the stacking test condition.

Efficiency enhancement of white light-emitting diodes via nano-textured silicone encapsulant.

Kim, Sang-Mook,Baek, Jong Hyeob,Hwang, Nam,Kim, Yong-Suk,Wi, Sung-Kwon,Um, Soong Ho,Jung, Gun Young American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.10

<P>We textured the surface of a silicone encapsulant to increase the extraction efficiency of white light-emitting diodes (LEDs) by using a plasma treatment. Here, the surface morphology could be controlled by changing the plasma condition and texturing morphology of the silicone encapsulant were proportion to the increased ratio of white LEDs. The luminous efficacy of the surface textured LEDs were increased 9.70% relative to the reference LED. Furthermore, the Fourier transform infrared spectroscopy spectrum showed that the chemical bonds of the silicone encapsulant were not changed by the argon-nitrogen plasma treatment, thereby reducing degradation of the optical characteristics and improving the reliability of LEDs.</P>

Validation of Data Migration for Science and Technology Contents

Sung-Ho Shin,Won-Goo Lee,Min-Ho Lee,Kwang-Young Kim,Hwa-Mook Yoon,Won-Kyung Sung 한국콘텐츠학회 2011 한국콘텐츠학회 ICCC 논문집 Vol.- No.-

Effects of Hydroxyl Group Numbers on the B-Ring of 5,7-Dihydroxyflavones on the Differential Inhibition of Human CYP 1A and CYP1B1 Enzymes

Kim Hyun-Jung,Lee Sang Bum,Park Song-Kyu,Kim Hwan Mook,Park Young In,Dong Mi-Sook The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.10

Flavonoids are polyphenols composed of two aromatic rings (A, B) and a heterocyclic ring (C). In order to determine the effects of the number of hydroxyl groups in the B-ring of the flavonoids on human cytochrome P450 (CYP) 1 family enzymes, we evaluated the inhibition of CYP1A-dependent 7-ethoxyresorufin O-deethylation activity by chrysin, apigenin and luteolin, using bacterial membranes that co-express human CYP1A1, CYP1A2, or CYP1B1 with human NADPH-cytochrome P450 reductase. Chrysin, which possesses no hydroxyl groups in its B-ring, exhibited the most pronounced inhibitory effects on CYP1A2-dependent EROD activity, followed by apigenin and luteolin. On the contrary, CYP1A1-mediated EROD activity was most potently inhibited by luteolin, which is characterized by two hydroxyl groups in its B-ring, followed by apigenin and chrysin. However, all of the 5,7-dihydroxyflavones were determined to similarly inhibit CYP1B1 activity. Chrysin, apigenin, and luteolin exhibited a mixed-type mode of inhibition with regard to CYP1A2, CYP1B1, and CYP1A1, with apparent Ki values of 2.4, 0.5, and 2.0 ${\mu}M$, respectively. These findings suggested that the number of hydroxyl groups in the B-ring of 5,7-dihydroxyflavone might have some influence on the degree to which CYP1A enzymes were inhibited, but not on the degree to which CYP1B1 enzymes were inhibited.

Polarity effect of the thimble-type ionization chamber at a low dose rate

Kim, Yong-Kyun,Park, Se-Hwan,Kim, Han-Soo,Kang, Sang-Mook,Ha, Jang-Ho,Chung, Chong-Eun,Cho, Seung-Yeon,Kim, J K Institute of Physics in association with the Ameri 2005 Physics in medicine & biology Vol.50 No.21

<P>It is known that the current collected from an ionization chamber exposed to a constant radiation intensity changes in magnitude when the polarity of the collecting potential is reversed. It is called the polarity effect of the ionization chamber. There are many possible causes that induce the polarity effect and one of them can be a field distortion due to a potential difference between the guard electrode and the collector. We studied how much the polarity effect depends on the design of the electrodes in the thimble-type ionization chamber. Two thimble-type ionization chambers, which had different electrode structures, were designed and fabricated at KAERI. We calculated the field distortions due to the potential difference between the guard electrode and the collector for the two ionization chambers. MAXWELL and Garfield were employed to calculate the electron drift lines inside the chamber. The polarity effects of the two ionization chambers were measured, and they were consistent with the field calculation. We could conclude that the polarity effect is mostly induced from the field distortion due to the potential difference between the guard electrode and the collector in our experiment and it depends significantly on the design of the electrodes.</P>