Reconstruction of Rabbit Corneal Epithelium on Lyophilized Amniotic Membrane Using the Tilting Dynamic Culture Method

Ahn, Jae-Il,Lee, Doo-Hoon,Ryu, Yang-Hwan,Jang, In-Keun,Yoon, Mun-Young,Shin, Youn Ho,Seo, Young-Kwon,Yoon, Hee-Hoon,Kim, Jae-Chan,Song, Kye-Yong,Yang, Eun-Kyung,Kim, Ki-Ho,Park, Jung-Keug Blackwell Publishing Inc 2007 Artificial Organs Vol.31 No.9

<P>Abstract: </P><P>Rabbit corneal epithelium was reconstructed using tilting dynamic culture with a self-manufactured, amniotic membrane (AM) supporter and a lyophilized amniotic membrane (LAM). Rabbit corneal epithelial (RCE) cells were cultured and cryopreserved after isolation from the limbus. The second- and third-passage RCE cells were plated onto the epithelial side of the LAM of Ahn's AM supporter. Two days later, the air–liquid interface culture was maintained with third-passage RCE cells for 6 days and second-passage corneal epithelial cells for 9 days. The average viability of thawed RCE cells, assessed using trypan blue dye exclusion, was 77.42%. The reconstructed corneal epithelium was characterized by histological (hematoxylin and eosin) and immunohistochemical staining (proliferating cell nuclear antigen) for light microscopy, and by reverse transcriptase-polymerase chain reaction, glucose assay, and transmission electron microscopy. The basal layer of the reconstructed corneal epithelium was well formed, and the epithelium was tightly constructed due to the increase in cell proliferation and differentiation caused by the tilting dynamic culture, as opposed to static culture. Tilting dynamic culture was useful for the reconstruction of the epithelium using easily damaged epithelial cells and resulted in more stratum cell layers. Moreover, cytokeratin (CK3) mRNA expression in tilting dynamic cultured third-passage RCE cells seeded onto AM was greater than in static cultured third-passage RCE cells. The morphology of the reconstructed corneal epithelium on LAM by tilting dynamic culture for 9 days resembled that of the skin epidermis. This was thought to be because the tilting dynamic culture not only accelerated the proliferation and differentiation of cells by physical or mechanical stimulation, but also ensured that the supply of medium was delivered to the basal cells more efficiently. Thus, the reconstruction of the corneal epithelium using LAM and tilting dynamic culture was considered to be a good in vitro model for autologous or allogeneic transplantation of corneal epithelium and skin epidermis in patients with damaged epithelia. </P>

뇌성마비아의 모발내 중금속 함량 분석

안경희,김희상,유창현,윤동환,홍장혁,유승돈,이준원 경희대학교 2001 慶熙醫學 Vol.17 No.1

손등 정맥 패턴의 회전 왜곡을 보상한 개인 식별 알고리즘의 연구

최환수,안장용 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

This paper proposes an enhanced algorithm for person identification system utilizing hand vein pattern. The conventional algorithm does not cope with distortion caused by image rotation caused by misplaced hands on the imaging device. A straightforward approach to consider the rotaional compensation required too much computational load, thus, we devised an approach to expect the rotation direction along with image translation, reducing the compuational requirement dramatically. In this paper, we present the detail of the algorithm with experimental results with the new algorithm.

흉쇄관절에 생긴 연쇄상구균 감염 후 반응성 관절염-증례 보고-

안경회,김희상,홍장혁,윤동환 大韓再活醫學會 2000 Annals of Rehabilitation Medicine Vol.24 No.6

Enhanced organic photovoltaic cells with MoOx nanorods as a hole transfer layer

Ahn, Jeong-Hwan,Ahn, Joon-Sub,Jang, Myeong-Jun,Han, Eun-Mi Informa UK (TaylorFrancis) 2017 Molecular Crystals and Liquid Crystals Vol.654 No.1

<P>Molybdenum oxide(MoOx) nanorods have been used as a hole transfer layer(HTL) for an organic photovoltaic(OPV) cell because it has a bandgap similar to that of PEDOT:PSS. The structure of OPV is a fluorine-doped tin oxide(FTO) / MoOx nanorod / P3HT:PCBM / ZnO / Ag. The morphology of the MoOx layer was controlled by the hydrothermal reaction time and the concentration of the precursor. The photoelectric conversion efficiency(PCE) was affected by widening the hole transfer surface between the HTL and the active layer. A device with 0.24 wt% MoOx precursor and a 20-min reaction time had a highest efficiency of 2.7%.</P>

Hybrid 적응 빔형성을 이용한 ATSC 시스템의 이동수신 성능개선

안장환(Jang-Hwan Ahn),문성훈(Sung-Hoon Moon),임채현(Chae-Hyun Lim),김경태(Jung-Tae Kim),한동석(Dong-Seog Han),김승원(Seung-Won Kim) 한국통신학회 2004 한국통신학회 학술대회 및 강연회 Vol.2004 No.4

Independent Risk Factors for Hepatocellular Carcinoma Recurrence after Direct-Acting Antiviral Therapy in Patients with Chronic Hepatitis C

( Young-hwan Ahn ),( Heirim Lee ),( Do Young Kim ),( Hye Won Lee ),( Su Jong Yu ),( Young Youn Cho ),( Jeong Won Jang ),( Byoung Kuk Jang ),( Chang Wook Kim ),( Hee Yeon Kim ),( Hana Park ),( Hyo Jung 대한간학회 2021 Gut and Liver Vol.15 No.3

Background/Aims: This study was performed to evaluate the efficacy of direct-acting antivirals (DAAs) in Korean patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) and to investigate the risk factors associated with HCC recurrence. Methods: A total of 100 patients with HCV-related HCC, who were treated with DAAs between May 2015 and December 2016, were recruited from seven university hospitals in Korea. Claim data of 526 patients with HCC obtained from the Health Insurance Review and Assessment Service in South Korea were used for external validation of the results. Results: Among the 100 patients, 88% achieved a sustained virological response (SVR) 12 weeks after the end of DAA therapy (SVR12), and 37% experienced HCC recurrence after DAA therapy. Short last HCC treatment durability (<12 months) before DAA commencement was independently associated with HCC recurrence (hazard ratio [HR], 2.89; p=0.011). In the nationwide validation cohort, 20.3% of the patients experienced HCC recurrence. The last HCC treatment with a noncurative method, a short last HCC treatment durability (<12 months), and a longer total duration of HCC treatment (≥18 months) were independently related with HCC recurrence (HR 3.73, p<0.001; HR 3.34, p<0.001; and HR 1.74, p=0.006; respectively). Conclusions: DAA therapy showed an acceptable SVR12 rate in patients with HCV-related HCC. Short last HCC treatment durability (<12 months) was associated with HCC recurrence after DAA therapy. This finding suggests that the last HCC treatment durability is an important predictor of HCC recurrence after DAA therapy. (Gut Liver 2021;15:410-419)

Transplantation of Reconstructed Corneal Layer Composed of Corneal Epithelium and Fibroblasts on a Lyophilized Amniotic Membrane to Severely Alkali-burned Cornea

Jang, In-Keun,Ahn, Jae-Il,Shin, Jun-Seop,Kwon, Young-Sam,Ryu, Yang-Hwan,Lee, Jeong-Kyu,Park, Jung-Keug,Song, Kye-Yong,Yang, Eun-Kyung,Kim, Jae-Chan Blackwell Publishing Inc 2006 Artificial Organs Vol.30 No.6

<P>Abstract: </P><P>The purpose of this article was to evaluate the graft efficacy of reconstructed corneal layer, composed of autologous corneal epithelium and fibroblasts on a lyophilized amniotic membrane (LAM), in a severely alkali-burned corneal model. After biopsy specimens were obtained from the left eyes of 24 rabbits, the corneal epithelial cells and fibroblasts were expanded in vitro and the corneal layer was reconstructed on LAM. Thirty-six eyes of rabbits underwent alkali burn (1 N NaOH, 30 s) to create a limbal deficiency and a deeply damaged corneal stroma. Four weeks later, group 1 underwent a graft of the reconstructed corneal layer composed of autologous corneal epithelium and fibroblasts on LAM. Group 2 was transplanted with a graft of the reconstructed autologous corneal epithelium, and group 3 served as a control without surgery. Wound healing and stabilization of the ocular surfaces occurred much faster in group 1 than in groups 2 and 3. The eyes in group 3 revealed typical limbal deficiencies with conjuctivalization and persistent corneal epithelial defects. However, the corneas in group 1 developed only mild peripheral neovascularization. Immunohistochemical staining in group 1 demonstrated that p63, cytokeratin 3, E-cadherin, transforming growth factor (TGF)-&bgr;1, and collagen IV were expressed strongly in the corneal epithelium and basement membrane. On the basis of these results, transplantation of the reconstructed corneal layer, composed of autologous corneal epithelium and fibroblasts on LAM, partially accelerated the recovery of the alkali-injured rabbit ocular surface, and might be useful therapeutically for the treatment of patients with severely damaged cornea.</P>

Flow patterns and heat transfer characteristics of flat plate pulsating heat pipes with various asymmetric and aspect ratios of the channels

Jang, Dong Soo,Lee, Joo Seong,Ahn, Jae Hwan,Kim, Dongwoo,Kim, Yongchan Elsevier 2017 Applied thermal engineering Vol.114 No.-

<P><B>Abstract</B></P> <P>The thermal performance of flat plate pulsating heat pipes (PHPs) in compact electronic devices can be improved by adopting asymmetric channels with increased pressure differences and an unbalanced driving force. The objective of this study is to investigate the heat transfer characteristics of flat plate PHPs with various asymmetric ratios and aspect ratios in the channels. The thermal performance and flow pattern of the flat plate PHPs were measured by varying the asymmetric ratio from 1.0 to 4.0, aspect ratio from 2.5 to 5.0, and heat input from 2 to 28W. The effects of the asymmetric ratio and aspect ratio on the thermal resistance were analyzed with the measured evaporator temperature and flow patterns at various heat inputs. With heat inputs of 6W and 12W, the optimum asymmetric ratio and aspect ratio for the flat plate PHPs were determined to be 4.0 and 2.5, respectively. With the heat input of 18W, the optimum asymmetric ratio and aspect ratio were determined to be 1.5 and 2.5, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Flat plate pulsating heat pipes with asymmetric and aspect ratios were tested. </LI> <LI> Flow patterns were investigated according to channel geometry and flow condition. </LI> <LI> Heat transfer characteristics were analyzed with various heat inputs. </LI> <LI> Optimum asymmetric and aspect ratios were suggested for maximum thermal performance. </LI> </UL> </P>

편측 종아리 절단장애인에서 두 가지 소켓에 따른 사용만족도와 보행특성 비교: 단일사례연구

김장환,성우성,안동영,심우섭 대구대학교 특수교육재활과학연구소 2015 특수교육재활과학연구 Vol.54 No.2

본 연구는 연즉 종아리 절단장애인을 대상으로 KBM(Kondylen-Bettung Munster) 및 TSB(Total Surface Bearing) 소켓이 각각 적용된 의지 착용이 사용만족도와 보행 특성에 미치는 영향을 알아보고자 하였다. 연구 대상자는 K-4 활동 수준으로 스포츠 활동에 적극적으로 참여하는 현측 종아리 절단장애인 1명을 선정하였다. 의지 사용만족도 설문지 (PEQ,prosthetic evaluation questionnaire)를 사용하여 만족도를 조사하였고,2분 보행검사 (2minute walk test)와 영상분석 프로그램을 통해 보행 능력 (capacity) 과 보장 (step length)을 비교하였다. 실험은 단일대상연구 중 A-B-A-B 디자인을 적용하였다. KBM 의지에 비하여 TSB 종아리 의지를 착용하였을 때,PEQ 설문 점수가 증가하였고,2분 보행검사 결과가 개선되었으며,건축과 절단측의 보장 차이가 강소하였다 본 연구를 통해 TSB 종아리의지가 소켓의 편안함과 현가기능 및 보행 능력을 향상시키고,같은 시간 동안 보다 멀리 걸을 수 있어 운동 능력이 개선되었으며,보행 동안 양측 다리의 보장이 더욱 대칭적으로 나타났다. 이러한 결과에 따라 종아리 절단장애인의 보행 편위 (gait deviation)를 감소시킬 수 있고 일상 생활 및 운동 활동에 보다 효율적일 수 있다는 임상적 사례를 제시한다. The purpose of this study was to investigate the differences of a prosthetic satisfaction and gait characteristics between KBM and TSB socket of prosthesis in unilateral transtibial amputee‘ An active (K-4 level) subject has participated in this study. A subjective completed the prosthesis evaluation questionnaire(PEQ) with embedded satisfaction-related questions, and underwent two minute walk test and quantitative two-dimensional motion analysis to compare the walking capacity and step length. This study is a single subject design (A - B-A-B). As a result, compared with a KBM socket, a TSB socket showed that composite scores for the PEQ and two minute walk test were increased, while a distance of step length between both legs was reduced. Through the result of this study, a comfort,suspension function and walking capacity were improved, and also steps were more symmetric during gait, when TSB socket was worn. It suggest that gait deviations were decreased when the prosthesis with TSB socket was adopted, so transtibial amputees were able to adapt their daily living and sporting activities effectively.