군 수부외상 미세수술 시뮬레이션 트레이닝의 효과

박철희 ( Chulhee Park ),김정민 ( Jung Min Kim ),경민규 ( Min Gyu Kyung ),이영호 ( Young Ho Lee ) 국군의무사령부 2023 대한군진의학학술지 Vol.54 No.1

Objective The importance of microsurgery is being emphasized for treatments of severe trauma or combat injuries. We constructed a low-fidelity microsurgical training program that can be applied and operated at all times in military hospitals. Then we conducted the study on its effectiveness and appropriate time interval of it. Method A low-fidelity microsurgery training program using a microsurgery microscope, artificial vessels, and chicken thigh blood vessels was formed. Nine military surgeons participated and performed the one-year program with three different time intervals. The training time intervals were 2 months, 4 months, and 6 months, respectively. The differences in performance after the program were analyzed. Results This microsurgery simulation training program was evaluated to significantly improve and maintain military surgeons' microsurgery proficiency. There was no significant difference of performance results between the 2-month interval program(26.87%) and the 4-month interval program(27.10%). On the other hand, the performance of the 6-month interval program(12.02%) was far below those of the other two. Conclusion To perform regularly the simplified low-fidelity microsurgery simulation trainings using nonliving objects is helpful in improving and maintaining military microsurgeons' skill and proficiency. In addition, it is appropriate in terms of time efficiency to conduct such training at intervals of 4 months.

Stimuli-Responsive Mesoporous Nanocontainer with Multifunctional A6 Peptide for Improved Drug Delivery Efficiency

Min-hyuek CHOI,Jeonghun LEE,Eun-Taex OH,Heon Joo PARK,Chulhee KIM 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Performance Comparison of Various Interpolation Methods for Motion Estimation

Min Jeung Lee,Chulhee Lee 대한전자공학회 2003 ITC-CSCC :International Technical Conference on Ci Vol.2003 No.7

Causal interpretation with board characteristics : Caveat emptor

Jong-Min Kim,Chulhee Jun,Hope H. Han 한국재무학회 2020 한국재무학회 학술대회 Vol.2020 No.08

The study of a causal interpretation of board and firm characteristics, that is, a hidden dependence relationship on the causal inference among board and firm characteristics, is an important but unaddressed issue in the corporate governance literature. Using diverse advanced statistical methods and focusing on Tobin’s Q, we find that i) not all board variables previously found to be significant are “robust” to latent variable data analysis, and ii) those variables that are consistently significant differ markedly in latent structural equation analysis. Our analyses provide researchers interested in board issues with an important caveat: focusing on the dependence structure of available board variables affected by latent factors may introduce a new horizon in corporate finance.

Regulation of PDGF signalling and vascular remodelling by peroxiredoxin II

Choi, Min Hee,Lee, In Kyung,Kim, Gyung Whan,Kim, Bang Ul,Han, Ying-Hao,Yu, Dae-Yeul,Park, Hye Sun,Kim, Kyung Yong,Lee, Jong Seo,Choi, Chulhee,Bae, Yun Soo,Lee, Byung In,Rhee, Sue Goo,Kang, Sang Won Nature Publishing Group 2005 Nature Vol.435 No.7040

Platelet-derived growth factor (PDGF) is a potent mitogenic and migratory factor that regulates the tyrosine phosphorylation of a variety of signalling proteins via intracellular production of H<SUB>2</SUB>O<SUB>2</SUB> (refs 1, 2–3). Mammalian 2-Cys peroxiredoxin type II (Prx II; gene symbol Prdx2) is a cellular peroxidase that eliminates endogenous H<SUB>2</SUB>O<SUB>2</SUB> produced in response to growth factors such as PDGF and epidermal growth factor; however, its involvement in growth factor signalling is largely unknown. Here we show that Prx II is a negative regulator of PDGF signalling. Prx II deficiency results in increased production of H<SUB>2</SUB>O<SUB>2</SUB>, enhanced activation of PDGF receptor (PDGFR) and phospholipase Cγ1, and subsequently increased cell proliferation and migration in response to PDGF. These responses are suppressed by expression of wild-type Prx II, but not an inactive mutant. Notably, Prx II is recruited to PDGFR upon PDGF stimulation, and suppresses protein tyrosine phosphatase inactivation. Prx II also leads to the suppression of PDGFR activation in primary culture and a murine restenosis model, including PDGF-dependent neointimal thickening of vascular smooth muscle cells. These results demonstrate a localized role for endogenous H<SUB>2</SUB>O<SUB>2</SUB> in PDGF signalling, and indicate a biological function of Prx II in cardiovascular disease.

코로나19 감염 재난이 시민 기부 행동에 미친 영향에 관한 연구: 해피빈 모금 프로젝트를 중심으로

민인식 ( Min Insik ),강철희 ( Kang Chulhee ),강아름 ( Kang Arum ) 한국사회복지연구회 2021 사회복지연구 Vol.52 No.4

본 연구는 감염 재난인 코로나19의 발생 초기 시민들의 전반적인 기부 행동 양상이 어떠한지를 목표달성률, 기부자수, 1인당 기부액으로 구체화하여 살핀다. 또한, 코로나19 발생 후 시민들의 기부 행동에 있어 모금 프로젝트 속성의 영향력을 살핀다. 이를 위한 분석자료는 2019년 12월 1일부터 2020년 4월 2일까지의 기간에 해피빈에서 관찰된 완료 또는 진행 중인 기부형 모금 프로젝트들이다. 분석 결과, 첫째, 코로나19 기간과 프로젝트의 모금 기간이 겹칠수록 목표달성률은 낮아졌고, 기부 참여자 수는 줄었으며 1인당 기부액은 감소했다. 둘째, 코로나19 프로젝트인지 아닌지의 속성 차이는 모금의 목표달성률에 대해 직접효과(+)와 조절효과(+)를 가졌다. 본 연구는 코로나19 발생 초기 온라인기부 플랫폼에서 이루어진 시민들의 실제적 기부 행동을 실증적으로 검증했다는 점에서 연구의 의미가 있다. COVID-19 is a severe pandemic that has made significant negative impacts on citizens’ daily lives. It could also affect citizens’ giving behavior. This study empirically examines the natural giving behavior under COVID-19 by using fundraising project data from the most popular online charitable crowdfunding platform, ‘Happybean’ in South Korea. The result shows that the more is the fundraising period of a project overlapped with the COVID-19 period, the lower is its fundraising outcome, the number of donors, and the amount of giving per person. In addition, it shows that the COVID-19 projects achieved a higher outcome than the non-COVID-19 projects. Simultaneously the result shows that the categories of COVID-19 projects and non-COVID-19 projects had a moderation effect in the relationship between the COVID-19 overlap period and fundraising outcome. The slope of non-COVID-19 projects was relatively much steeper in a negative direction than the slope of COVID-19 projects. It implies that donors who continue to care their neighbors’ needs prioritize disaster-related issues over non-COVID-19 issues. This study contributes to understanding and promoting citizens’ giving behavior in the early period of the COVID-19.

Removal of broken syndesmotic screw with minimal bone defects in Korea: a case report

Kyung Min Gyu,Park Chulhee 대한외상학회 2023 大韓外傷學會誌 Vol.36 No.3

Ankle fractures with syndesmotic injuries often require fixation, where metal screw fixation is a popular method. However, as the patient begins weight-bearing, most syndesmotic screws tend to loosen or break, and removal of such screws has been challenging for the surgeons, as the available techniques require predrilling or trephination and are associated with risks of bone damage. This study presents a case with technical tip for the removal of broken tricortical-fixed non-cannulated syndesmotic screws. It implements the generation of a small cortical window in the medial distal tibia and the use of pliers to engage the screw tip and remove through the medial side. The technique presented in the current study overcomes these limitations and facilitates minimal bone damage and reduced exposure to radiation.

Gamma-irradiation and doxorubicin treatment of normal human cells cause cell cycle arrest via different pathways.

Lee, Seong Min,Youn, BuHyun,Kim, Cha Soon,Kim, Chong Soon,Kang, ChulHee,Kim, Joon Korean Society for Molecular Biology 2005 Molecules and cells Vol.20 No.3

<P>Ionizing radiation and doxorubicin both produce oxidative damage and double-strand breaks in DNA. Double-strand breaks and oxidative damage are highly toxic and cause cell cycle arrest, provoking DNA repair and apoptosis in cancer cell lines. To investigate the response of normal human cells to agents causing oxidative damage, we monitored alterations in gene expression in F65 normal human fibroblasts. Treatment with g-irradiation and doxorubicin altered the expression of 23 and 68 known genes, respectively, with no genes in common. Both agents altered the expression of genes involved in cell cycle arrest, and arrested the treated cells in G2/M phase 12 h after treatment. 24 h after g-irradiation, the percentage of G1 cells increased, whereas after doxorubicin treatment the percentage of G2/M cells remained constant for 24 h. Our results suggest that F65 cells respond differently to g-irradiation- and doxorubicin-induced DNA damage, probably using entirely different biochemical pathways.</P>

보편적 보육료 지원정책이 여성 노동공급과 출산율에 미친 영향

민규량 ( Gyuryang Min ),이철희 ( Chulhee Lee ) 한국노동경제학회 2020 勞動經濟論集 Vol.43 No.4

본 연구는 영유아 보육료 지원정책이 보육시설공급률에 따라 노동공급과 출산율에 상이한 영향을 미쳤음을 분석하였다. 구체적으로 보육시설공급률이 높을수록 보육료 지원에 의해 보육시설 입소에 유리한 다자녀모의 경력유지 확률이 증가했을 뿐 아니라 첫째 자녀의 출산율이 높아졌고, 국공립 어린이집의 공급률이 높은 경우에는 보육비 지원 이후 둘째 자녀 출산율도 유의하게 높아졌음을 보여 준다. 이는 보육료 지원정책의 효과가 출생순위에 따른 보육시설 입소 우선순위, 거주지역 보육시설의 양적, 질적 공급 정도에 따라 달라짐을 보여준다. This paper investigates how the provision of full child care subsidy to infants and toddlers differently affected female labor supply and fertility rate depending on the level of supply of child care centers in the place of residence. Our results on labor supply show that the higher the supply rate of childcare centers in residential areas, the higher the probability of career maintenance for multi-child mothers who are more likely to be admitted to a childcare facility. The results on the fertility rate show that the first child's fertility rate has increased since the support of childcare expenses in areas with higher rates of childcare centers. In the places where the supply rate of publicly-funded childcare centers is high, the second child's fertility rate has also increased significantly since the support of childcare expenses. This suggests that the quality of child care is an essential factor in determining the birth rate. Our results suggest that the effects of child care support on women's labor supply and fertility rate may differ depending on the priority of entering child care centers according to birth order and the degree of quantitative and qualitative supply of child care centers in the place of residence.

Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

Han, Yung-Min,Han, Chulhee,Kim, Wan Ho,Seong, Ho Yong,Choi, Seung-Bok Institute of Physics Publishing 2016 Smart materials & structures Vol.25 No.9

<P>This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.</P>