자궁경부암 병기판정 기초검사시 새로운 보조방법으로서 고주파 질식 초음파의 가치

유희석,이은주,장기홍,권혁찬,양정인,김행수,오기석 아주대학교 의과학연구소 1996 아주의학 Vol.1 No.1

To investigate the efficacy of endoluminal ultrasound system (EUS) as a surrogate for high frequency transvaginal ultrasonography and as an optional baseline study in determining parameirial and stromal invasion of early stage cervical cancer, 52 women suspected of cervical cancer underwent EUS. A 12 MHz endoscopic probe was employed to radially scan the cervix for possible lesions suspected to be invasive cancer during a period of 6 months from Feb. 1 to July 1, 1995. Patients also underwent magnetic resonance imaging (MRI) and/or computerized tomography (CT) as a routine mode of baseline study, and were clinically staged by 3 independent physicians specializing in Obstetrics and Gynecology at the Department of Obstetrics and Gynecology, School of Medicine, Ajou University, Suwon, Korea. Thirty one patients subsequently received surgery appropriate for the stage of the disease and the final pathology findings were compared with the results of clinical staging, EUS, MRI/CT by regression analysis. The results showed that there was statistically significant correlation between MRI/CT and pathology (r=0.660, p<0.02), between EUS and pathology (r=0.803, p<0.01), and between clinical staging and pathology (r=0.825, p<0.01). It is concluded that there was significant statistical correlation t>etween EUS, MRI/CT, clinical staging and pathology, but the question remained as to the statistical superiority of EUS over MRI/CT with regard to parametrial invasion and stromal invasion depth assessment. Finally, EUS is useful as an alternative optional diagnostic tool in the baseline study of cervical cancer.

A Novel Interference Cancellation Technique for Turbo Coded CDMA Systems

Hyuck-Chan Kwon,Ki-Jun Kim,Keum-Chan Whang 한국통신학회 1999 한국통신학회 학술대회논문집 Vol.1999 No.11

SC-FDMA Uplink 용 직렬 간섭제거기의 성능 고찰

권혁찬(Hyuck-Chan Kwon),장일두(Il-Doo Chang) 한국통신학회 2013 한국통신학회 학술대회논문집 Vol.2013 No.1

Clinical Outcomes of Obese Recipients (BMI≥30) in Living Donor Liver Transplantation

( Chan Woo Cho ),( Ji Soo Lee ),( Gyu-seong Choi ),( Jong Man Kim ),( Choon Hyuck ),( David Kwon ),( Jae-won Joh ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Obese recipients increases difficulty on the aspect of retaining acceptable graft-to-recipient weight ratio (GRWR) in living donor liver transplantation (LDLT). The aim of our study was to assess clinical outcomes of LDLT in obese recipients (BMI≥30) and find acceptable criteria in terms of small for size graft (SFSG). Methods: We performed a retrospective study to validate LT outcomes of obese recipients who were defined as body mass index (BMI) ≥30 and who underwent LDLT from January 2001 to December 2015 at a single institute. Based on GRWR, obese recipients were divided into Group 1 (GRWR ≤ 0.8) and Group 2 (GRWR > 0.8), and assessed posttransplant study parameters included incidence of early allograft dysfunction, primary nonfunction, and hospital mortality. Results: 61 patients (5.3%) were obese recipients in the middle of 1131 cases who underwent LDLT during the study period. Group 1 included 30 recipients and Group 2 included 31 recipients. In baseline characteristics, there were no significant difference between 2 Groups except for GRWR (0.73 versus 0.97; p < 0.001). Hospital stay after LDLT did not show significant difference between two groups (29 versus 27 days; p = 0.217). In Group 1, hospital mortality were 2 (6.7%) cases, and cause of death was graft dysfunction caused by SFSG and sepsis by pneumonia. In Group 2, hospital mortality were 4 cases (12.9%); 2 cases of primary nonfunction (PNF), 1 case of aspiration pneumonia, and intraabdominal bleeding. In the Kaplan-Meier analysis for graft survival, 10-year graft survival in Group 1 and 2 was 76 % and 65 %, respectively. Conclusions: LDLT in obese patients represented unfavorable outcomes in terms of postoperative mortality, and graft survival. However, Low graft weight did not impact outcomes after LDLT

Fusion Licensing and Safety Studies in Korea

Hyuck Jong Kim,Hyung Chan Kim,Myeun Kwon,Gyunyoung Heo,In-Ju Hwang,Soon Heung Chang,Jong Kyung Kim,Yong Su Kim IEEE 2014 IEEE transactions on plasma science Vol.42 No.3

<P>Korean activities on fusion licensing and safety studies have been going through three phases. The first phase started with the licensing of the Korean Superconductor Tokamak Advanced Research (KSTAR) classified as a radiation-generating device on the basis of the existing nuclear regulations. To accommodate the specific characteristics of a tokamak device that is to use deuterium in fusion plasma physics studies, a set of instructions to examine the safety of KSTAR and to approve an operating permit were developed and issued by the regulatory body, Korean Institute of Nuclear Safety. The second phase is being investigated for the International Thermonuclear Experimental Reactor (ITER). To verify the design of the test blanket module that will be installed and tested in the ITER, safety studies were carried out using the experimental results and computational codes. To minimize occupational irradiation damages, a study on the tritium behaviors is being carried out as Korea will provide a part of the tritium systems of ITER. The last phase has initiated to recognize significant safety issues and to support future licensing process for a fusion DEMO plant. Relevant studies are being carried out in collaboration with the academies funded by the National Fusion Research Institute of Korea. These front-end studies include the conceptual analysis on the safety and radiological consequences, preliminary studies on the layout of research, and on the future regulatory requirements of the fusion DEMO plant. This paper summarizes these activities on fusion safety with the findings of the front-end studies to date. It also proposes a pathway for the novel licensing process of a fusion DEMO plant with the tokamak concept.</P>

Clinical Efficacy of Pretransplant Vaccination for Preventing Herpes Zoster after Living Donor Liver Transplantation in Recipients Aged 50 years and Older

( Chan Woo Cho ),( Jong Man Kim ),( Gyu-seong Choi ),( Choon Hyuck David Kwon ),( Jae-won Joh ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: There have been no reports concerning the efficacy of pretransplant herpes zoster (HZ) vaccination following living donor liver transplantation (LDLT). From January 2013 to May 2016, 24 patients aged 50 years and older received vaccination of HZ prior to transplantation and underwent LDLT at a single institution. Methods: We compared this to the one-year HZ incidence of unvaccinated recipients (N=180) who underwent LDLT in the same time frame. Results: For general characteristics, the MELD scores (P<0.001) and CTP grades (P=0.007) of the vaccinated group were significantly lower than those of unvaccinated group. In Kaplan-Meier analysis, the one- year HZ incidence rates of the vaccinated and unvaccinated groups were two (8.7%) and 16 (9.9%) cases, respectively (P=0.883). In the subgroup aged 50 through 59 years, two vaccinated recipients had HZ after LDLT. However, in the subgroup aged 60 years and older, no vaccinated recipients had HZ after LDLT. Multivariate analysis showed the independent risk factor for HZ after LDLT was use of mycophenolate mofetil (MMF; hazard ratio [HR] = 3.00; P=0.041). Conclusions: The efficacy of pretransplant vaccination for preventing HZ was not apparent in our study. A large prospective study is needed to determine the indications for pretransplant HZ vaccination according to age group and to evaluate the efficacy of HZ vaccination after LDLT.

Comparative Short-term Outcomes of Laparoscopic Anatomical Liver Resection for the Centrally Located Tumor: Case-matched Study with Propensity Score Matching

( Chan Woo Cho ),( Meshal Saleh Aldosri ),( Nasser Alzerwi ),( Kyeong Sik Kim ),( Seounghyun Kim ),( Ji Soo Lee ),( Jonghwan Lee ),( Nuri Lee ),( Choon Hyuck David Kwon ),( Jong Man Kim ),( Gyu-seong 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Recent advanced technology and an accumulation experience of surgeons have expanded the indications for laparoscopic liver resection. However, compared with open liver resection, laparoscopic anatomical liver resection for centrally located tumor has not been well established in terms of feasibility. The aim of our study was to assess the feasibility and safety of laparoscopic anatomical major liver resection for the centrally located tumor. Methods: From September 2005 to April 2015, 138 consecutive anatomical major liver resections for the centrally located tumor such as central hepatectomy (CH) and right anterior sectionectomy (RAS) were performed, including 14 cases of totally laparoscopic anatomical liver resections. In order to compensate the selection bias, we performed one or/and up to five match using propensity score matching between laparoscopic and open liver resection. Results: After propensity score matching, 14 and 39 patients were included in the Laparoscopic liver resection (LLR) and Open liver resection (OLR) group, respectively. Surgical time was longer in the LLR group (393, range 131 to 661 minutes) than the OLR group (270, range 92 to 500 minutes) (p = 0.001), but the hospitalization was shorter (8, range 5 to 24 days versus 11, range 5 to 183 days, p = 0.061). The portal triad clamping time was shorter (15 versus 25 minutes, p = 0.833) and mean blood loss was less in LLR (471 versus 489 mL, p = 0.603) but the values were not statistically significant. The morbidity rates were 36% (5 of 14 cases) in the LLR group and 28% (11 of 39 cases) in the OLR group. There was no postoperative mortality in either group. Conclusions: Laparoscopic approach for CLT requiring CH or RAS seems feasible with non-inferior outcome perioperative compared to OLR. CLT may be performed safely by totally laparoscopic approach in experienced hands.

자연 월경주기와 Clomiphene Citrate 유도주기를이용한 체외수정 및 배아이식술의 의의

권혁찬,임성호 대한산부인과학회 1993 Obstetrics & Gynecology Science Vol.36 No.4

Ovulation induction with various hormonal agents has become a standard component of in vitro fertilization (IVF) cycles to obtain multiple oocytes. Among the advantages of controlled ovarian hyperstimulation are the increased numbers of oocytes and thus embryos that are available for embryo transfer (ET) and the enhanced cycle control that is achievable, especially with the concurrent use of the gonadotropin-releasing hormone analogues(GnRH-a) However, controlled ovarian hyperstimulation increases the cost of the cycle and is associated with decreased endometrial receptivity. In addition, some patients, including those with regular ovulatory cycles, do not respond to ovarian stimulatory drugs. Recent communications have reported successful pregnancies after IVF in unstimulated cycles and clomiphene citrate stimulation cycle, triggered with or without human chorionic gonadotropin(hCG). In this study, our objections is to describe the clinical experience of our center with in vitro fertilization(IVF) in unstimulated cycles and clomiphene stimulated cycles and to provide a comparison to each other. We report our results in 67 patients, 96 cycles spontaneously ovulatory women with predominatly pelvic and tubal factor as their principal cause of infertility, under the age of 40 and no male factor, and 26 patients, 34 cycles clomiphene citrate stimulated ovulatory women with additional ovulatory factor. In the ninty six spontaneously ovulatory cycles, sixty six follicle aspirated cycles(oocyte retrieval rate ; 68.8%) resulted in nine clinical pregnancies(18.4%)and in the thirty four clomiphene citrate stimulated ovulatory cycles, twenty seven follicles aspirated cycles(oocyte retrieval rate ; 79.4%) resulted in three clinical pregnancies(15.8%). There was no statistically significance in pregnancy rate between two groups.

Experimental Investigation of Physical Mechanism for Asymmetrical Degradation in Amorphous InGaZnO Thin-film Transistors under Simultaneous Gate and Drain Bias Stresses

Chan-Yong Jeong,Hee-Joong Kim,Jeong-Hwan Lee,Hyuck-In Kwon 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.2

We experimentally investigate the physical mechanism for asymmetrical degradation in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) under simultaneous gate and drain bias stresses. The transfer curves exhibit an asymmetrical negative shift after the application of gate-to-source (VGS) and drain-to-source (VDS) bias stresses of (VGS = 24 V, VDS = 15.9 V) and (VGS = 22 V, VDS = 20 V), but the asymmetrical degradation is more significant after the bias stress (VGS, VDS) of (22 V, 20 V) nevertheless the vertical electric field at the source is higher under the bias stress (VGS, VDS) of (24 V, 15.9 V) than (22 V, 20 V). By using the modified external load resistance method, we extract the source contact resistance (RS) and the voltage drop at RS (VS, drop) in the fabricated a-IGZO TFT under both bias stresses. A significantly higher RS and VS, drop are extracted under the bias stress (VGS, VDS) of (22 V, 20V) than (24 V, 15.9 V), which implies that the high horizontal electric field across the source contact due to the large voltage drop at the reverse biased Schottky junction is the dominant physical mechanism causing the asymmetrical degradation of a-IGZO TFTs under simultaneous gate and drain bias stresses.

여성의 골반 염증과 불임

權赫璨 대한의사협회 1999 대한의사협회지 Vol.42 No.9