In-Situ X-Ray Fluoroscopic Observation for Motion of Bubbles in Liquid Iron for Correction of Drag Coefficient Used in Numerical Simulation

In-Beom Park,Sang-Joon Kim,Hae-Geon Lee,Youn-Bae Kang 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.4

Rising of Ar bubble in C-saturated liquid iron was investigated in-situ by employing a high power X-Ray fluoroscope (maximum power of 450 kV and 4.5 mA) coupled with a high speed camera. This analysis enabled to track the actual motion of rising bubble in the liquid iron. After post-processing of X-Ray images, size, shape, velocity, and trajectory of the bubble were obtained. The bubbles were found to be not spherical, but ellipsoidal. Their average size could be estimated about 1.1×10 -2 m. The bubbles wobbled during rising and arrived at their terminal velocities within 0.1 sec. The obtained terminal velocities revealed that the governing forces acting on the motion of ellipsoidal bubble were inertia and surface force. This was quite different from that of spherical bubble which was widely used in the assumption for the numerical analysis. As a result, widely applied equation for the drag coefficient (CD = 24 (1 + 0.15Re 0.687 ) / Re) is seen to be applicable only for low Re regime, and this was also confirmed by the drag coefficient derived from the present experimental observation. Therefore, it is suggested to use the following equation for the drag coefficient CD = max [24 (1 + 0.15Re 0.687 ) / Re, 8Eo / 3(Eo + 4)]. Numerical simulation for the Ar bubble behavior in the three dimensional (3D) continuous casting mold was conducted in order to evaluate the effect of the drag coefficient for the behavior of spherical and ellipsoidal bubbles. The numerical results showed that the increased CD based on ellipsoidal regime affected the entire fluid in the mold.

In-depth considerations for better polyelectrolytes as interfacial materials in polymer solar cells

Yeo, Jun-Seok,Kang, Minji,Jung, Yen-Sook,Kang, Rira,Lee, Seung-Hoon,Heo, Youn-Jung,Jin, Sung-Ho,Kim, Dong-Yu,Na, Seok-In Elsevier 2016 Nano energy Vol.21 No.-

<P><B>Abstract</B></P> <P>We perform a comprehensive study to achieve better polyelectrolytes (PEs) as electron-transport layers (ETLs) in polymer solar cells (PSCs). Three well-known PEs – PFN, PEIE, and WPF – are chosen as model systems and investigated with variations in their backbone structures and the state of the amine functionalities on their side chains. Respectively optimized PSCs using the three PEs exhibit different cell-performances, mainly owing to the diode characteristics of built-in potential and recombination strength. To identify how such deviated device-performances correlate with the structural features of PEs, the modulated interfaces of ITO/PEs and PEs/active layer are studied in detail. It is found that conjugated backbones and larger counter-anions on side chains can promote the modulation of ITO work functions (WFs) and that a large amount of protonated amines on PEs is beneficial for junction properties with a subsequent active layer. Additionally, our results indicate that interfacial dipole and electrical doping between the PE and active layer, in addition to WF modulation of the ITO cathode, are important for device efficiency. Accordingly, with the aid of the molecular features of PEIE, PEIE-PSCs exhibit excellent device efficiency and stability compared with PFN- and WPF-PSCs. In the PTB7-th:PC<SUB>71</SUB>BM system, a remarkable power-conversion efficiency of 9.97% is achieved with a single PEIE ETL.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chemical structure and performance of polyelectrolytes (PEs) in PSCs are correlated. </LI> <LI> Interfacial dipole and doping between PEs and active layer lead to efficient PSCs. </LI> <LI> PEIE-based PSCs have excellent device efficiency and high stability. </LI> <LI> Especially, in the PTB7-th system, encouraging efficiency of 9.97% is achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The Effect of Rosiglitazone on the Cell Proliferation and the Expressions of p27 and Skp2 in<i>Helicobacter pylori</i>Infected Human Gastric Epithelial Cells

Kim, Sung-Soo,Cho, Young-Seok,Kim, Hyung-Keun,Shin, Ok-Ran,Chae, Hiun-Suk,Choi, Myung-Gyu,Chung, In-Sik The Korean Society of Gastroenterology 2010 대한소화기학회지 Vol.55 No.4

<P>Background/Aims: Ligands for peroxisome proliferator-activated receptorgamma (PPARgamma), a member of the ligand-activated nuclear receptor superfamily, exhibit anti-tumoral effects and are associated with de novo synthesis of proteins involved in regulating the cell cycle and cell survival/death. Helicobacter pylori (H. pylori) is an etiologic agent for gastric adenocarcinoma, and raises the cell turnover of gastric epithelium. The aim of this study was to investigate the effect of PPARgamma ligand rosiglitazone on the cell proliferation and the expressions of p27 and Skp2 protein in H. pylori infected gastric epithelial cells. Methods: We examined the expression of PPARgamma by Western blot in H. pylori infected AGS human gastric epithelial cells. The effect of rosiglitazone on the survival of H. pylori infected AGS cells was assessed by cell viability assay. After the treatment of rosiglitazone in H. pylori infected AGS cells, the expressions of p27 and Skp2 were assessed by Western blot. Results: The expression of PPARgamma protein was increased in H. pylori infected AGS cells. Cell growth was inhibited and decreased in dose- and time- dependent manner in H. pylori infected AGS cells treated with rosiglitazone. A decrease in Skp2 expression and a reciprocal increase in p27 expression were found in dose- and time-dependent manner in H. pylori infected AGS cells treated with rosiglitazone. Conclusions: Rosiglitazone inhibited the growth of H. pylori infected AGS cells. Rosiglitazone attenuated Skp2 expression, thereby promoting p27 accumulation in H. pylori infected human gastric epithelial cells. Further studies will be needed to find the effects of accumulation on cell turnover in H. pylori infection and the role in the H. pylori-associated gastric carcinogenesis.</P>

In-hospital mortality in patients with STEMI admitted during off hours

( Sung-Soo Kim ),( Myung Ho Jeong ),( Jeong Gwan Cho ),( Young Keun Ahn ),( Jong Hyun Kim ),( Shung Chull Chae ),( Young Jo Kim ),( Seung Ho Hur ),( In Whan Seong ),( Taek Jong Hong ),( Dong-hoon Choi 대한내과학회 2013 대한내과학회 추계학술대회 Vol.2013 No.1

Conflicting results exist on the outcome of off hours PCI in ST elevation myocardial infarction (STEMI). However, there were only a few studies that have focused on the clinical characteristics and outcomes of off hours PCI in STEMI. So, we studied the clinical characteristics and hospital mortality in STEMI patients treated with primary PCI during regular hours (weekdays 9:00 AM to 6:00 PM) versus off hours Weekdays 6:01 PM to 8:59 AM, weekends, and holidays) in Korea Acute Myocardial Infarction Registry. We analyzed in hospital and one year mortality among 5,665 consecutive ST segment elevation myocardial infarction patients treated with primary PCI between November 2005 to January 2008. Total 2,848 (50.2%) patients were treated during off hours. Baseline finding were similar, although regular hours patients were older. Median symptom to balloon time (304 min, IQR 175 to 750 vs. 270 min, IQR 145 to 551, p=0.001) were longer for regular hours primary PCI. Median door to balloon time (71min, IQR: 48 to 132 vs. 59 min, IQR 39 to 110 min, p=0.001) were longer for off hours pPCI. Also, Cardiac enzyme such as Max CK-MB (212.1±299.3 vs 194.7±303.4, p=0.031) and max TnI (72.6±239.5 vs. 58.9±94.4, p=0.013) were increased in off hours pPCI. However, unadjusted in hospital (6.0% off hours vs. 6.0% regular hours, p=0.946) and one year cardiac mortality (11.3% off hours vs. 11.7% regular hours, p=0.661) were comparable. In multivariate analysis, off hours primary PCI did not predict an adverse outcome. In conclusion, when primary PCI was performed within an appropriate reperfusion strategy, the clinical effectiveness of either off hours or regular hours pPCI is comparable.

Skin Safety of the UV Absorbers by Measurement Cytotoxicity High Functional Product with Water-In-Silicone System

( Kim In-young ),( Kim Min-ho ),( Nam Sang-in ),( Chun Kil Whan ) 대한화장품학회 1997 대한화장품학회지 Vol.23 No.3

Consumers have recently preferred to purchase extensive UV intercepting products, which are waterproof and free from side effects on skin. Testing Cytotoxicity (in-vitro) in SK method, cell survival ratio of UV-B interceptors decreased above 0.08W/V%, and so did that of UV-A interceptors above 0.06W/V%. Also, Patch-test of inorganic UV interceptors resulted in no skin irritation ever below 10.0 and 11.25. UV interceptors in the sunlight showed yellowish discoloration in 5 to 14 days. In absorption curves, UV-B was most suitable for Octyl methoxycinnamate (OMC) and UV-A for Butyl methoxy dibenzoylmethane (BMDM). For this reason, Nylonpoly UVA/UVB the material of OMC and BMDM coated with Nylon & polyethylene, was used as the organic UV interceptor. And zinc oxide (ZnO) and titanium dioxide (TiO,) was used as inorganic UV interceptors. The appropriate mixture ratio of ZnO and TiO, was 6 to 4. 6% of ZnO, 4% of TiO, and 5% of Nylonpoly UVA/UVB were all combined with our sunscreen cream. The SPF value of in-vivo applied to a guinea pig was 34.9 and that of in-vivo was 38.5. Cyclomerhicone and dimethicone were used in water-in-Silicone system. Ceryl dimethi-cone and sorbitan sesquiolente were used as emulsifiers and MgSO, · 7 H₂O, Mg-stearate/Mg-Al-stearate copolymer as emulsification stabilizers. In practical application, each SPF duration of O/’W type and W/S type containing sunscreen cream of the same content showed that W/S type of sunscreen cream was 5 times as durable as the other. This product is fit for using in swimming, climbing or skiing. This research is to minimize skin trouble caused by UV interceptors and to make one with proper softness, skin safety and UV intercepting efficiency.

Selection of drought-tolerant durum (Triticum turgidum L.) and common wheat (Triticum aestivum L.) from Korea and Tunisia

Sang Heon Kim,Dae Yeon Kim,Yacoubi Inès,Yong Jin Lee,Oonha Shin,Jin-Seok Yoon,Woo-Joo Jung,Yong Weon Seo 한국육종학회 2013 한국육종학회 심포지엄 Vol.2013 No.07

Drought tolerance is the ability of a plant to live, grow, and reproduce properly with limited water supply or under periodic conditions of water deficit. However, the climate changes and worldwide water shortages would result in the loss of applied water to irrigated land, increasing soil water deficit. To control the situation, we have carried out the international joint research project for the aim of developing that drought tolerance common wheat and durum wheat in Korea and Tunisia. Total 79 (41 common wheat, 39 durum wheat) Tunisian lines and 33 Korean wheat cultivars were incorporated in this study. Drought stress was applied for 25 days of stopping irrigation from the 3-leaf stage followed by re-watering for restoration in greenhouse. We selected top 13 (5 Korean line, 8 Tunisian line) tolerant lines and 11 (5 Korean, 6 Tunisian) susceptible lines based on growth parameter analysis. Primers (Operon primers and wheat Dreb1 gene) that have been known to be related drought resistance were applied to explain selected population. The correlation between PCR-based length polymorphism of selected lines and their resistance were evaluated. The obtained primer information will aid selection for drought tolerance durum as well as hexaploid common wheat.

In-line 마그네트론 스퍼터 장치를 사용하여 산소 분위기에서 제작한 Ag 박막의 특성

구대영,김원목,조상무,황만수,이인규,정병기,이택성,이경석,조성훈,Ku, Dae-Young,Kim, Won-Mok,Cho, Sang-Moo,Hwang, Man-Soo,Lee, In-Kyu,Cheong, Byung-Ki,Lee, Taek-Sung,Lee, Kyeong-Seok,Cho, Sung-Hun 한국재료학회 2002 한국재료학회지 Vol.12 No.8

A study was made to examine the electrical, compositional, structural and morphological properties of Ag thin films deposited by DC magnetron sputtering in $O_2$ atmosphere with deposition temperature from room temperature to 15$0^{\circ}C$ using in-line sputter system. The Ag films deposited at temperature above $100^{\circ}C$ in oxygen atmosphere gave a similar specific resistivity to and even lower oxygen content than those deposited using pure Ar sputter gas The Ag films deposited with pure Ar gas was mainly composed of crystallites with [111] preferred orientation, while, for those deposited in oxygen atmosphere, more than 50% of the volume was composed of crystallites with [100] orientation. The difference in the micro structure did not cause any difference in the specific resistivity of Ag films. The results showed that the transparent conducting oxide films and the Ag films could be processed sequentially in the same deposition chamber with careful control of deposition temperature, which might result in a cost reduction for constructing the large scale in-line deposition system.

Selection of salt-tolerant common wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. subsp. durum) from Korea and Tunisia

Sang Heon Kim,Dae Yeon Kim,Yacoubi Inès,Oonha Shin,Jin Seok Yoon,Woo Joo Jung,Yong Weon Seo 한국육종학회 2014 한국육종학회 심포지엄 Vol.2014 No.07

Soil salinity limits crop productivity in many regions. This problem would be more serious as the global climate changes and worldwide water shortages would accelerate soil salinization. This study is fulfilled with aim on resolve crop cultivation in dry/saline land as an international joint research project with Tunisia. Total 48 lines of wheat cultivars including 32 common wheat (16 Korean wheat, 16 Tunisian common wheat) and 16 Tunisian durum wheat were incorporated in this study. Salt stress was applied for 2 weeks by submerging the pots into 500 mM NaCl at 3-leaf stage followed by re-watering for restoration in greenhouse. Numerous agronomic/growth parameters were scored for tolerence. SSR primers that have been known to be related to salt tolerance were applied to explain selected population. The correlation between PCR-based length polymorphism of selected lines and their resistance were evaluated. The obtained information will aid selection for salt tolerance hexa/tetraploid wheats. Acknowledgement: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2012K1A3A1A09028123) and carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project title: Development of high yielding wheat with stress tolerance via molecular breeding strategies, Project No. PJ008031)”, Rural Development Administration, Republic of Korea.

<i>In vitro</i> and <i>in vivo</i> evaluation of a novel polymer-free everolimus-eluting stent by nitrogen-doped titanium dioxide film deposition

Park, Dae Sung,Bae, In-Ho,Jeong, Myung Ho,Lim, Kyung Seob,Sim, Doo Sun,Hong, Young Joon,Lee, So-Youn,Jang, Eun Jae,Shim, Jae-Won,Park, Jun-Kyu,Lim, Han Chul,Kim, Han Byul Elsevier 2018 Materials Science and Engineering C Vol.91 No.-

<P><B>Abstract</B></P> <P>Inflammation and thrombosis are linked to the use of polymer-based drug-eluting stents (DES). The aim of this study was to develop a polymer-free everolimus (EVL)-eluting stent using nitrogen-doped titanium dioxide (N-TiO<SUB>2</SUB>) and verify its efficacy by <I>in vitro</I> and <I>in vivo</I> assessment in a porcine coronary model. Various analytical approaches such as scanning electron microscopy and atomic force microscopy, electron spectroscopy, Fourier transform infrared spectrometry and contact angle measurement were employed for the characterization. As a part of biocompatibility assessment, platelet adhesion and smooth muscle cell (SMC) proliferation were examined. Bare metal stent (BMS), N-TiO<SUB>2</SUB> stent, everolimus-eluting N-TiO<SUB>2</SUB> (N-TiO<SUB>2</SUB>-EVL) stent, and commercialized EVL-eluting stent (EES) were randomly placed in forty coronary arteries in twenty pigs. After four weeks of implantation, the stents were subjected to histological and quantitative analysis. The N-TiO<SUB>2</SUB> film used in this study was well coated without any cracks or peeling. Surface hydrophilicity (88.8% of angle decrement) could be associated with the decrease in surface roughness post N-TiO<SUB>2</SUB> deposition (37.0%). The platelet adhesion on the N-TiO<SUB>2</SUB> surfaces was less than that on the BMS surface. The proliferation of SMC was suppressed in the N-TiO<SUB>2</SUB>-EVL group (30.2%) but not in the BMS group. In the animal study, the percent area restenosis was significantly decreased in the N-TiO<SUB>2</SUB>-EVL group compared to that in the BMS group. The results (BMS; 47.0 ± 11.00%, N-TiO<SUB>2</SUB>-EVL; 31.7 ± 10.50%, and EES; 29.1 ± 11.21%, <I>n</I> = 10, <I>p</I> < 0.05) were almost at par with those of the commercialized EVL-eluting stent. The introduction of N-TiO<SUB>2</SUB> deposition during fabrication of polymer-free DES may be an efficient accessorial process for preventing in-stent restenosis and thrombosis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-TiO<SUB>2</SUB> surfaces can help to reduce the platelet adhesion. </LI> <LI> In porcine model, N-TiO<SUB>2</SUB> everolimus decreased in-stent restenosis and fibrin deposition. </LI> </UL> </P>

Genetic Variations of the Apolipoprotein B Gene in Korean People and Its Association with Hypercholesterolemia

Sung Han Kim,Un Kyung Kim,Jae Jin Chae,Jeong In Baek,Soo Young Choi,Jae Woong Bae,Sang Hyun Kim,Hyo Soo Kim 한국유전학회 2008 Genes & Genomics Vol.30 No.5

Genetic polymorphisms at the apolipoprotein B have been associated with elevated plasma concentrations of LDL, atherosclerosis and increased risk of coronary artery disease. 106 individuals composed of 46 hypercholesterolemic patients and 60 controls were analyzed with Ins/Del length polymorphism, four RFLPs (HincII, PvuII, AluI, EcoRI) and 3`-VNTR to clarify the characteristics of the apolipoprotein B gene and to determine their influence on the lipid profile of hypercholesterolemic patients and controls in Korea. A total of 212 apolipoprotein B alleles from six markers were identified in this study. Heterozygosityranges from zero to 0.32, and the genotyope frequencies in the case of 3`-VNTR are significantly different between two groups. Analysis of linkage disequilibrium revealed paired nonrandom associations between four pairs of polymorphic sites of the apolipoprotein B gene (p<0.05). Moreover, addition of all 4 polymorphic sites provided the highest PIC value. This study also investigated the association of these polymorphisms with the patients and with variation in lipid levels. A significant association between 3`-VNTR genotypes and Lp(a) was observed in hypercholesterolemic patients (p<0.05). The results suggest that genotypes of six polymorphic markers were not significantly associated with TC, TG or LDL-chol level between the patients and controls in the Koreans.