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>

Factors of Cardiopulmonary Resuscitation Outcome for In-hospital Adult Patients

In Byung Kim,Sang Won Chung,Dong Seok Moon,Ki Hyun Byun Korean Society of Critical Care Medicine 2007 Acute and Critical Care Vol.22 No.2

BACKGROUND: The purpose of this study was to evaluate the factors of cardiopulmonary resuscitation (CPR) outcome for in-hospital adult patients, acquiring data with standardized reporting guideline of in-hospital cardiopulmonary resuscitation in Korea. METHODS: All adult cardiac arrest patients from July 2004 to December 2006 in this general hospital were included. Their clinical spectrums were reviewed retrospectively using Utstein-style based template. RESULTS: For the study time period, one hundred and forty-two patients underwent cardiac arrest in this hospital. 136 patients were performed CPR. Return of spontaneous circulation (ROSC) occurred in 42 cases, and 15 patients were survived to hospital discharge. A shorter CPR time and a lower Simplified Acute Physiology Score II (SAPS II) were significant for survivor to hospital discharge (p

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.

Recurrent thrombosis after endovascular treatment for malignant superior vena cava syndrome

( Sang Ho Lee ),( Sun Young Kim ),( Heung Tae Kim ),( Chang Woo Shim ),( Ho Seok Chi ),( Hye In Lee ),( Do Il Choi ),( Hyun Bum Kim ),( In Jun Lee ) 대한내과학회 2015 대한내과학회 추계학술발표논문집 Vol.2015 No.1

Endovascular treatment (EVT) including angioplasty and stenting is an effective treatment for superior vena cava (SVC) syndrome. Recurrence of SVC syndrome is mainly caused by tumor progression and occurs in around 20% after EVT, but sometimes venous thrombosis within stent accounts for recurrence of SVC syndrome. Anticoagulation after EVT is still a controversial issue. In our case, a 73 year-old man with SVC syndrome caused by mediastinal lymph node metastasis from non-small cell lung cancer underwent EVT followed by anticoagulation with low molecular weight heparin (LMWH), but symptomatic progression due to in-stent thrombosis necessitated the second procedure after two weeks. A total of 4 sessions of EVT and anticoagulation with LMWH, warfarin and rivaroxaban did not induce durable resolution of in-stent thrombosis. The 4th EVT was done with stent -graft, but computed tomography after the last procedure revealed remained thrombus in SVC and newly developed pulmonary thromboembolism during warfarinization. Our case suggests refractory in-stent thrombosis could develop despite of anticoagulation after EVT for SVC syndrome.

National survey of Korean hepatobiliary-pancreatic surgeons on attitudes about the enhanced recovery after surgery protocol

Sang Hyun Shin,Woo-hyoung Kang,In Woong Han,Yunghun You,Huisong Lee,Hongbeom Kim,Woohyun Jung,Yong Chan Shin,Jin Seok Heo 한국간담췌외과학회 2020 Annals of hepato-biliary-pancreatic surgery Vol.24 No.4

Backgrounds/Aims: The purpose of this study was to investigate attitudes regarding the Enhanced Recovery After Surgery (ERAS) protocol of hepato-biliary-pancreatic (HBP) surgeons in Korea and the extent to which they use the protocol for perioperative management. Methods: An online survey was conducted among members of the Korean Association of Hepato-Biliary-Pancreatic Surgery (KAHBPS) for eight weeks beginning on August 2019. The questionnaire, which was written in Korean, was based on the latest ERAS guidelines. Total responses were collected from 127 surgeons. Results: Of the 127 total respondents, the largest proportion (44.9%) were working in Seoul. In terms of established in-hospital clinical pathways (CP), 19.7% of the participating surgeons had and followed a CP in pancreaticoduodenectomy (PD) and 21.3% in hepatectomy. Regarding the ERAS protocol for each surgery, four items (18.2%) regarding PD and seven items (35.0%) related to hepatectomy were followed by more than 50% of respondents. Conclusions: ERAS guidelines are one of the consensuses for better recovery in perioperative management of patients undergoing major surgeries and encompass the overall process of patient recovery including patient education, pain control, physiologic balance, and perioperative nutrition. A novel project is needed to successfully implement an evidence-based enhanced recovery strategy.

<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>

Effects of Phenytoin and Diazepam on the Seizure Activity in the Cortical Dysplasia Animal Models

Kim, Si-Hyung,Choi, In-Sun,Cho, Jin-Hwa,Park, Eun-Ju,Jang, Il-Sung,Choi, Byung-Ju,Kim, Hyun-Jung,Kim, Young-Jin,Nam, Soon-Hyeun The Korean Academy of Oral Biology 2006 International Journal of Oral Biology Vol.31 No.2

Dysplasia-associated seizure disorders are markedly resistant to pharmacological intervention. Relatively little research has been conducted studying the effects of antiepileptic drugs(AEDs) on seizure activity in a rat model of dysplasia. We have used rats exposed to methylazoxymethanol acetate(MAM) in utero, an animal model featuring nodular heterotopia, to investigate the effects of AEDs in the dysplastic brain. Pilocarpine was used to induce acute seizure in MAM-exposed and age-matched vehicle-injucted control animals. Field potential recordings were used to monitor amplitude and numbers population spikes, and paired pulse inhibition in response to stimulation of commissural pathway. Two commonly used AEDs were tested: diazepam 5, 2.5mg/kg;phenytoin 40, 60mg/kg. Diazepam(DZP) and phenytoin(PHT) reduced the amplitude of population spike in control and MAM-exposed rats. However, the amplitude of population spike was nearly eliminated in control rats as compared to the MAM-exposed rats. Pharmaco-resistance was tested by measuring seizure latencies in awake rats after pilocarpine administration(320mg/kg, i.p.) with and without pretreatment with AEDs. Pre-treatment with PHT 60 mg prolonged seizure latency in control rats, but not in MAM-exposed animals. The main findings of this study are that acute seizures initiated in MAM-exposed rats are relatively resistant to standard AEDs assessed in vivo. These data suggest that animal model with cortical dysplasia can be used to screen the effects of potential AEDs.

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 추계학술발표논문집 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.

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>