Glycerol/Silk Fibroin Film for Corneal Endothelial Cells

국현,심보라,김은영,주천기,강길선 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.10

Aloe Vera Gel/Silk Fibroin Film for Corneal Endothelial Cells

국현,김도경,김은영,주천기,이동원,강길선 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.10

Silk Fibroin Scaffolds as a Transporter to Deliver Demineralized Bone Particles for Bone Defect Treatment

국현,김은영,Nirmalya Tripathy,송정은,강길선 한국고분자학회 2015 한국고분자학회 학술대회 연구논문 초록집 Vol.2015 No.10

와이브로 상향링크에서 개방형 전력제어를 위한 상/하향 전력제어 계단값 설정 방법

국현,김중빈,김동우,Guk, Hyun,Kim, Jung-Bin,Kim, Dong-Woo 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.7a

와이브로 상향링크의 경우 개방형 전력제어에서는 피드백 없이 전력 할당을 하기 때문에 피드백에 사용될 무선자원을 절약 할 수는 있지만 단말에 정확한 전력 할당을 하기 어렵다. 이에 본 논문은 잡음간섭 값을 현재 무선 환경에 적응하는 방법을 제시하여 순시적으로 변화하는 무선 환경에 적합하게 하고 전력 할당의 상/하향 계단값 결정 방법을 대칭형과 비대칭형으로 제안하여 비교 실험하였다. 컴퓨터를 이용한 실험을 통해서 시스템 파라미터에 따라 상/하향 계단값을 다르게 적용할 때 높은 섹터 처리율과 낮은 오류율 결과를 얻을 수 있다는 것을 알 수 있다. In this paper, we describe how to set up/down step-size in open loop power control for WiBro reverse link. Since open loop power control does not use feedback information, it is difficult to efficiently use wireless resource with accurate power control. We also provides a method of estimating levels of noise and interference. With numerical investigation, asymmetric up/down power-control step-size is shown to be promising to achieve high sector throughput as well as low error rate.

와이브로 상향링크에서 개방형 전력제어를 위한 상/하향 전력제어 계단값 설정 방법

국현,김중빈,김동우 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.7

Biphasic Mechanical Responses of Rat Thoracic Aorta to Irradiation with $250{\sim}500\;nm$ Light

국현,Kook, Hyun The Korean Society of Pharmacology 1995 대한약리학잡지 Vol.31 No.3

이 실험은 여러 파장$(240{\sim}520\;nm)$의 자외선 또는 가시광선(이후 '광선'이라 표기함)을 흰쥐흉부대동맥에 조사하여 이때의 혈관장력의 변화 및 조직내 cyclic GMP농도의 변화를 관찰하기위하여 시행하였다. 돼지관상동맥 또는 흰쥐 흉부대동맥의 환상표본에 spectrofluorometer의 xenon lamp를 이용하여 여러 파장의 광선을 조사하고 이때의 장력변동을 polygraph상에 기록하였다. Cyclic GMP농도변화는 표본에 광선을 조사한 직후 조직을 얼리고 homogenization 및 원침시킨 후 상청액을 ether로 추출하여 RIA kit로 측정하였다. Phenylephrine으로 수축된 내피존재 흰쥐 흉부 대동맥에서는 광선조사로 수축반응을 보였고 320 nm에서 최대수축반응을 일으켰다. 그 이상의 파장에서는 점차 수축반응이 감소되어 420 nm에서는 최대 이완반응을 일으킨 후 점차 기본장력으로 회복되었다. 그러나 내피제거 표본에서는 전파장에서 이완반응만을 일으켰고 이때 최대 이완반응은 370 nm에서 관찰되었다. 내피존재 표본에서 320, 380 및 420 nm의 광선을 30초간 조사한 결과 380과 420nm에서 현저한 cyclic GMP의 증가가 관찰되었으나 320 nm에서는 유의한 변동이 없었다. 한편, 내피제거 표본에서는370 nm의 광선조사로 cyclic GMP함량이 약 4배 증가하였다. 이상의 성적으로부터 흰쥐 흉부대동맥은 광선조사에 의하여 내피존재 표본에서는 수축-이완의 이상성반응을, 제거표본에서는 이완반응만을 일으키고 양 표본의 이완반응은 nitric oxide-cyclic GMP계의 활성화에 기인하나 수축반응은 cyclic GMP계와 직접 관련성이 없는 것으로 추론하였다. This study was undertaken to define the varying responses of vascular smooth muscle to different wavelengths of ultraviolet radiation and to relate them to the changes in cyclic GMP contents. The ring preparations of rat thoracic aorta with intact or removed endothelium were irradiated with the ultraviolet or visible light (UVR) of wavelengths in step of 10 nm between 250 and 500 nm from xenon lamp of a spectrofluorometer, and the changes in vascular tension were recorded. For cyclic GMP assay, the preparations, pretreated with phenylephrine as in the tension experinents, were frozen after irradiation and homogenated in trichloroacetic acid. The supernatant was extracted with ether and the cyclic GMP contents were measured with radioimmunoassay. In the endothelium-intact preparations, biphasic responses, vasoconstriction (UVR-contraction) followed by vasodilatation (UVR-dilatation), were observed. The maximal UVR-contraction was observed at 320 nm, while the maximal vasodilatation was elicited at 420 nm. In the endothelium-removed rings, however, only vasodilatation was observed, with the maximal vasodilatation taking place at 370 nm. The cyclic GMP contents were not affected by the Irradiation with 320 nm for 30 sec or 1 min in the endothelium-intact preparations, while it was significantly increased by 380 and 420 nm. In the endothelium-removed preparations, UVR of 370 nm markedly increased the cyclic GMP contents. The present study indicates that the increase in cyclic GMP is closely related to vasodilatation induced by UVR of 420 nm in the endothelium-intact or 370 nm in the denuded preparations, whereas it is not involved in the vasoconstriction induced by UVR of 320 nm in the intact rings, and the mechanism leading to UVR-contraction remains to be clarified. These observations suggest that nitric oxide-cyclic GMP system is closely related to the UVR-dilatation in rat aortic preparation, while it is not involved in the UVR contraction.

Amiloride-sensitive $Na^+$ Channels Are Not Involved in the Cardiovascular Responses to Increased $Na^+$ Concentration in Cerebrospinal Fluid

국현,김재하,백영홍,Kook, Hyun,Kim, Jae-Ha,Baek, Yung-Hong The Korean Society of Pharmacology 1994 대한약리학잡지 Vol.30 No.3

$Na^+$ 이동에 관여하는 약물을 가토 측뇌실내로 투여하여 나타난 반응을 관찰함으로써 심혈관 조절 중추의 $Na^+$ channel과 뇌척수액내 $Na^+$ 농도의 상승에 의한 심혈관 반응과의 관계를 밝히고자 하였다. 1 M NaCl $200{\mu}l$을 urethane으로 마취된 가토의 측내실내로 투여시 승압과 서맥이 나타났고 이 서맥은 미주신경 절단으로 빈맥으로 역전되었다. $Na^+$ 이동억제제인 amiloride의 뇌실내 투여는 승압 및 서맥을 일으켰고 미주신경 절단으로 영향을 받지 않았으며 NaCl주입에 의한 심혈관계 반응에 영향을 미치지 않았다. Amiloride 유도체인 benzamil은 그 자체로도 심혈관계 반응에 아무런 영향을 미치지 않았을 뿐 아니라 NaCl의 효과에도 영향을 주지 않았다. 미주신경 절단 가토에서 amiloride는 NaCl에 의한 빈맥을 서맥으로 역전시켰으나, 그 서맥의 정도는 NaCl의 전처치로 영향받지 않았다. 이상의 성적으로 amiloiride와 benzamil이 심혈관계에 미치는 영향은 각기 다르나 그들 모두 NaCl에 의한 심혈관계 반응에는 아무런 영향을 미치지 않음을 알았다. 이로부터 심혈관 조절 중추내 amiloride나 benzamil에 민감한 $Na^+$ channel은 NaCl-유발 반응과는 관련이 없을 것이라 추론하였다. This study was undertaken to investigate the relationship between the $Na^+$ channels of the cardiovascular regulation center and the responses to increased $Na^+$ concentration in the cerebrospinal fluid (CSF), by observing the effects of icv administration of the agents affecting $Na^+$ transport. Icv infusion of $200\;{\mu}l$ of 1 M NaCl produced hypertension and bradycardia in the urethane-anesthetized rabbit, and the bradycardia was inhibited and reversed to tachycardia by vagotomy. Amiloride, a $Na^+$ transport inhibitor, produced hypertension and bradycardia, which were not altered by vagotomy, and it did not affect the NaCl-induced responses. Benzamil, a derivative of amiloride with higher specificity, neither produced any cardiovascular effects by itself, nor affected the NaCl-induced responses. In vagotomized rabbits, icv amiloride reversed the NaCl-induced tachycardia to a bradycardia, but the bradycardiac effect was not altered by pretreating with NaCl. This study showed that although amiloride and benzamil slightly differ in their cardiovascular action, neither of them did affect the NaCl-induced responses. We suggest that the $Na^+$ channels which are sensitive to amiloride or benzamil in the cardiovascular regulation center are not involved in the NaCl-induced response.

우리나라 의사 국가시험 필기시험(2016–2018)의 기초의학 역량 평가 현황의 분석

국현,오세옥,이덕주,기선호,전용성 연세대학교 의과대학 2023 의학교육논단 Vol.25 No.1

Basic medical education is important for developing the competencies of medical doctors, and it includes basic biomedical sciences, preventive medicine, medical ethics, and clinical science. This study aimed to reveal the current status of the Korean Medical Licensing Examination (KMLE) regarding its evaluation of competencies in basic biomedical sciences. The basic medicine-related questions were screened and selected from the test forms of the KMLE (2016–2018) by personnel conducting basic biomedical science education, and the selected questions were analyzed by three independent groups of undergraduate students at Chonnam National University Medical School in terms of the learning outcomes of basic medical education. The study scope includes the proportion of basic medicine-related questions, which consist of basic medicine questions and basic medicine-related clinical medicine questions, its annual change, discipline distribution, and associated learning outcomes. The average proportions of basic biomedical sciences, preventive medicine and medical law, and clinical sciences were 2.3%, 5.8%, and 91.9% of all questions, respectively. The proportion of basic medicine-related questions, except those on preventive medicine and medical law, was 22.0% of the total, and questions on pharmacology and microbiology accounted for 83.0% of the basic medicine-related questions. The proportion of sub-enabling learning outcomes linked with basic medicine-related questions comprised 14.0% of the total outcomes for basic biomedical sciences and 30.4% for preventive medicine and medical law. It is concluded that the KMLE questions may not sufficiently cover the essential competencies of basic medical education for medical doctors, and the KMLE may need to be improved with regard to competencies in basic biomedical sciences.

비디오 모델링을 이용한 출생 직후 고위험 신생아간호 시뮬레이션 교육이 간호대학생의 의사소통 자기효능감, 비판적 사고능력, 임상수행능력에 미치는 효과

국현이 한국간호연구학회 2023 한국간호연구학회지 Vol.7 No.3

Purpose : The purpose of this study is to analyze the effect of high-risk neonatal nursing simulation education using video modeling on the communication self-efficacy, critical thinking ability and clinical performance in nursing students. Methods : A non-equivalent control group pretest-posttest design was used. The experimental group applied a video modeling simulation program, and the control group applied a scenario-based role play-oriented simulation program. The study participants included 78 nursing students (40 in experimental group and 38 in control group) from G city. A simulation module consisted of a orientation and lecture, pre-learning, problem-based learning, scenario operation, debriefing. Data were analyzed using χ2-test, independent t-test, Fisher’s exact test, paired t-test, ANCOVA. Results : The experimental group showed a significant increase in communication self-efficacy (t=2.33, p=.023, d=.538) and clinical competence (F=17.50, p<.001, ηp2 =.189) compared to the control group. Conclusion : The High-risk neonatal nursing simulation program using video modeling was effective in improving students’ communication self-efficacy and clinical competence. The neonatal nursing simulation education using video modeling applied in this study is expected to be one of the learning strategies that can significantly increase the effectiveness of HFS by adding learning methods tailored to the needs of students familiar with the media.

자동차 차체 서브 어셈블리 부품 변형량 측정 Gauge 개발 연구

국현일(Hyeonil Kook) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11