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김훈(Hun Kim),조성식(Sung-sik Jo),임태균(Tai-gyun Lim),장은실(Eun-sil Jang),박세필(Sei-fil Park),김갑기(Kab-ki Kim) 한국정보기술학회 2010 Proceedings of KIIT Conference Vol.2010 No.-
본 논문에서는 FCC(연방 통신위원회)에서 지정한 UWB(Ultra-wideband) 주파수 대역(3.1~10.6㎓)을 만족하는 UWB 원형 슬롯 패지 안테나를 설계하였다. 제안된 안테나는 광대역화를 위해 원형 패치 안에 반원형 슬롯을 삽입하였으며, 후면 방사에 대한 간섭을 줄이기 위해 부분접지를 이용하였다. 유전율은 4.4, 두께가 2㎜, 손실이 없는 FR-4 기판으로 설계하였다. 시뮬레이션 결과 -10㏈이하에서 양호한 반사손실을 가졌고, UWB 전대역에서 VSWR 2이하를 만족하였다. In this paper a circular slot patch antenna is designed satisfying UWB(Ultra-wideband) frequency(3.1~10.6) in FCC(Federal Communication). The proposed antenna inserted semi-circular slot for wide-band and obtained to decrease the back radiation by a partial ground plane for extending bandwidth. The substrate is desinged on loss-free FR-4 with relative dielectric constant 4.4 and thickness 2㎜. Simulations show that has good retuen loss below -10 ㏈ over the bandwidth and has good VSWR(2:1).
Jeon, Sei-Woong,Choi, Jong-Hun,Jang, Tae-Won,Moon, Seung-Myung,Hwang, Hyung-Sik,Jeong, Je-Hoon The Korean Neurosurgical Society 2011 Journal of Korean neurosurgical society Vol.49 No.6
Objective : Subdural hygroma (SDG) is a complication occurring after head trauma that may occur secondary to decompressive craniectomy (DC). However, the mechanism underlying SDG formation is not fully understood. Also, the relationship between the operative technique of DC or the decompressive effect and the occurrence and pathophysiology of SDG has not been clarified. Purpose of this study was to investigate the risk factors of SDG after DC in our series. Methods : From January 2004 to December 2008, DC was performed in 85 patients who suffered from traumatic brain injury. We retrospectively reviewed the clinical and radiological features. For comparative analysis, we divided the patients into 2 groups : one group with SDG after craniectomy (19 patients; 28.4% of the total sample), the other group without SDG (48 patients; 71.6%). The risk factors for developing SDG were then analyzed. Results : The mean Glasgow Outcome Scale (GOS) scores at discharge of the groups with and without SDG were 2.8 and 3.1, respectively (p<0.0001). Analysis of radiological factors showed that a midline shift in excess of 5 mm on CT scans was present in 19 patients (100%) in the group with SDG and in 32 patients (66.7%) in the group without SDG (p<0.05). An accompanying subarachnoid hemorrhage (SAH) was seen in 17 patients (89.5%) in the group with SDG and in 29 patients (60.4%) in the group without SDG (p<0.05). Delayed hydrocephalus accompanied these findings in 10 patients (52.6%) in the group with SDG, versus 5 patients (10.4%) in the group without SDG (p<0.05). On CT, compression of basal cisterns was observed in 14 members (73.7%) in the group with SDG and in 18 members of the group without SDG (37.5%) (p<0.007). Furthermore, tearing of the arachnoid membrane, as observed on CT, was more common in all patients in the group with SDG (100%) than in the group without SDG (31 patients; 64.6%) (p<0.05). Conclusion : GOS showed statistically significant difference in the clinical risk factors for SDG between the group with SDG and the group without SDG. Analysis of radiological factors indicated that a midline shifting exceeding 5 mm, SAH, delayed hydrocephalus, compression of basal cisterns, and tearing of the arachnoid membrane were significantly more common in patients with SDG.
Han, Sei-Myoung,Han, Sang-Hun,Coh, Ye-Rin,Jang, Goo,Chan Ra, Jeong,Kang, Sung-Keun,Lee, Hee-Woo,Youn, Hwa-Young Nature Publishing Group 2014 Experimental and molecular medicine Vol.46 No.6
<P>Mesenchymal stem cells (MSCs) are attractive candidates for clinical repair or regeneration of damaged tissues. Oct4 and Sox2, which are essential transcription factors for pluripotency and self-renewal, are naturally expressed in MSCs at low levels in early passages, and their levels gradually decrease as the passage number increases. Therefore, to improve MSC proliferation and stemness, we introduced human Oct4 and Sox2 for conferring higher expansion and differentiation capabilities. The Oct4-IRES-Sox2 vector was transfected into human adipose tissue MSCs (ATMSCs) by liposomal transfection and used directly. Oct4 and Sox2 were successfully transfected into ATMSCs, and we confirmed maintenance of MSC surface markers without alterations in both red fluorescent protein (RFP) (control) and Oct4/Sox2-ATMSCs. Enhanced proliferative activity of Oct4/Sox2-ATMSCs was shown by WST-1 assay, and this result was further confirmed by cell counting using trypan blue exclusion for a long period. In addition, FACs cell cycle analysis showed that there was a reduction in the fraction of Oct4/Sox2-ATMSCs in G1 with a concomitant increase in the fraction of cells in S, compared with RFP-ATMSCs. Increased levels of cyclin D1 were also seen in Oct4/Sox2-ATMSCs, indicating acceleration in the transition of cells from G1 to S phase. Furthermore, Oct4/Sox2-overexpressing ATMSCs showed higher differentiation abilities for adipocytes or osteoblasts than controls. The markers of adipogenic or osteogenic differentiation were also upregulated by Oct4/Sox2 overexpression. The improvement in cell proliferation and differentiation using Oct4/Sox2 expression in ATMSCs may be a useful method for expanding the population and increasing the stemness of ATMSCs.</P>
Han, Sang-Hun,Jang, Goo,Bae, Bo-Kyoung,Han, Sei-Myoung,Koh, Ye-Rin,Ahn, Jin-Ok,Jung, Woo-Sung,Kang, Sung-Keun,Ra, Jeong-Chan,Lee, Hee-Woo,Youn, Hwa-Young Published for the International Federation for Cel 2014 Cell biology international Vol.38 No.10
<P>Enhancing the proliferative capacity of mesenchymal stem cells (MSCs) is critical for increasing their therapeutic potential in a variety of diseases. We hypothesized that lentivirus-mediated overexpression of canine octamer-binding transcription factor 4 (OCT4) might influence the proliferation of canine adipose tissue-derived MSCs (cATMSCs). cOCT4-cATMSCs were generated by transducing cATMSCs with a cOCT4-lentiviral vector. Increased expression of cOCT4 was confirmed using RT-PCR and immunoblotting. Immunophenotypic characterization using flow cytometry indicated that the CD29, CD44, CD73, CD90, and CD105 surface markers were highly expressed by both cOCT4- and mock-transduced cATMSCs (mock-cATMSCs), whereas the CD31 and CD45 markers were absent. We performed the osteogenic differentiation assay to evaluate the effects of cOCT4 overexpression on the osteogenic differentiation potential of cATMSCs. The results showed that cOCT4-cATMSCs had a much higher potential for osteogenic differentiation than mock-cATMSCs. Next, the proliferative capacities of cOCT4- and mock-cATMSCs were evaluated using a WST-1 cell proliferation assay and trypan blue exclusion. cOCT4-cATMSCs showed a higher proliferative capacity than mock-cATMSCs. Cell cycle analysis indicated that overexpression of cOCT4 in cATMSCs induced an increase in the proportion of cells in S and G2/M phases. Consistent with this, immunoblot analysis showed that cyclin D1 expression was increased in cOCT4-cATMSCs. In conclusion, our results indicate that lentivirus-mediated overexpression of cOCT4 increased the proliferative capacity of cATMSCs. OCT4-mediated enhancement of cell proliferation may be a useful method for expanding MSC population rapidly without loss of stemness.</P>
수소발생반응을 위한 Ni₄Cr 나노 섬유 전기화학 촉매 합성 및 특성 분석
이정훈(Jeong Hun Lee),장명제(Myeong Je Jang),박유세(Yoo Sei Park),최승목(Sung Mook Choi),김양도(Yang Do Kim),이규환(Kyu Hwan Lee) 한국표면공학회 2017 한국표면공학회지 Vol.50 No.5
Hydrogen evolution reaction(HER) was studied over Ni₄Cr nanofibers(NFs) prepared by electrospinning method and oxidation/reduction heat treatment for alkaline water electrolysis. The physicochemical and electrochemical properties such as average diameter, lattice parameter, HER activity of synthesized Ni₄Cr NFs could be modified by proper electrospinning process condition and reduction temperature. It was shown that Ni₄Cr NFs had average diameter from 151 to 273 nm. Also, it exhibited the overpotential between 0.419 V and 0.526 V at 1 mA/㎠ and Tafel slope of -334.75 mV to -444.55 mV per decade in 1 M KOH solution. These results indicate that Ni₄Cr NFs with reduction heat treatment at 600 oC show thinnest diameter and highest HER activity among the other catalysts.
Park, Yoo Sei,Lee, Jeong Hun,Jang, Myeong Je,Jeong, Jaehoon,Park, Sung Min,Choi, Woo-Sung,Kim, Yangdo,Yang, Juchan,Choi, Sung Mook Elsevier 2020 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.45 No.1
<P><B>Abstract</B></P> <P>Co<SUB>3</SUB>S<SUB>4</SUB> nanosheets on Ni foam (NS/NF) were prepared by sulfurization for various time after calcination of electrodeposited Co(OH)<SUB>2</SUB>. In our FE-SEM images, we observed that Co<SUB>3</SUB>S<SUB>4</SUB> NS was vertically, or obliquely, deposited on the Ni foam. As a result, the structure contained more active sites, and active sites were highly accessible to the electrolyte for the hydrogen evolution reaction (HER). Furthermore, results of XPS and XRD analysis confirmed S-conversion from Co<SUB>3</SUB>O<SUB>4</SUB> to Co<SUB>3</SUB>S<SUB>4</SUB> during sulfurization. 3-Co<SUB>3</SUB>S<SUB>4</SUB> NS/NF with sulfurization for 3 h exhibited the highest sulfur content, while Co<SUB>3</SUB>S<SUB>4</SUB> began to desulfurize to Co<SUB>9</SUB>S<SUB>8</SUB> after sulfurization for 4 h. The 3-Co<SUB>3</SUB>S<SUB>4</SUB> NS/NF electrocatalyst showed a lowest overpotential of 93 mV at −10 mA/cm<SUP>2</SUP>, with a Tafel slope of −55.1 mV/dec in N<SUB>2</SUB>-purged 1 M KOH. Also, the single cell anion exchange membrane water electrolyzer (AEMWE) showed a high current density of 431 mA/cm<SUP>2</SUP> with cell voltage 2.0 V<SUB>cell</SUB> at 40–45 °C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Co<SUB>3</SUB>S<SUB>4</SUB> nanosheets on Ni foam was prepared by electrodeposition and sulfurization for various time. </LI> <LI> The Co<SUB>3</SUB>S<SUB>4</SUB> nanosheets on Ni foam with sulfurization for 3 h indicated the highest sulfur content. </LI> <LI> The Co<SUB>3</SUB>S<SUB>4</SUB> nanosheets on Ni foam with sulfurization for 3 h showed a lowest overpotential of 93 mV at −10 mA/cm<SUP>2</SUP> in 1 M KOH. </LI> <LI> The single cell anion exchange membrane water electrolyzer (AEMWE) showed a high current density of 431 mA/cm<SUP>2</SUP> at 2.0 V<SUB>cell</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
알코올성 간경변 환자에서 위대망 정맥류 출혈로 인한 자발성 혈복강 1 예
채희복,윤세진,박선미,성노현,배일헌,임정묵,장이찬,최기원,신종성,지정훈 대한간학회 2001 Clinical and Molecular Hepatology(대한간학회지) Vol.7 No.3
Portal hypertension often leads to the development of several collateral vessels that shunt blood flow from the portal to the systemic circulation. The rupture of intra-abdominal varix is an unusual complication of portal hypertension that can lead to life-threatening hemoperitoneum of the patient is herrmdynamically unstable due to massive intra-abdominal bleeding, exploratory laparotomy should be performed on the patient. There are several reported cases of intra-abdominal variceal bleeding such as paraumbilical varix, the varix from the small intestine and proximal colon etc. Spontaneous hemoperitoneum caused by the rupture of gastroepiploic vein varix, however, has not been repzted in Korm, to the best of our knowledge. We wiU discuss a patient with portal hypnsion due to liver cirrhosis who pnmented with acute intra-abdominal bleeding. During the laparotomy, he was found to have a rupture of the gastnxpiploic vein. 'Ihe vessel was ligated, and the patient recovered uneventfully by operative variceal ligation. (Korean J Hepatol 2001;7:336-340)