말기 신부전증을 동반한 전신성 홍반성 낭창 환자에서 동종 신장이식 증례

김호연,박준철,민병석,김진숙,방병기,이영석,고용복,이용각,김용일 대한신장학회 1983 Kidney Research and Clinical Practice Vol.2 No.2

In systemic lupus erythematosus renal involvement is very common and it accounts for the leading cause of death of the disease. Since SLE is a systemic disease involving many organs and it is caused by altered immunological background many physicians tend to hesitate in employing hemodialysis and renal transplantation. We report the first renal transplantion in Korea which was performed in a patient with end-stage renal failure due to SLE. The patient had positive LE pre- parations, low serum complement, antibody to native DNA and renal biopsy showing diffuse proliferative lupus nephritis but she manifested decreasing clinical activity during hemodialysis. The patient received kidney allograft from living related donor after unilateral nephrectomy. There was no clinical or his- tological evidence of rejection or recurrence of lupus nephritis in the grafted kidney. The patient maintains normal renal function 18 months after renal trans- plantation.

췌장암에서 Cyclooxygenase - 2 발현의 역할

김은경,이용욱,이규택,최규완,박동일,백승운,이준행,이종균,고광철,이풍렬,이종철,김재준,김완선,공구 대한소화기학회 2001 대한소화기학회지 Vol.38 No.3

Background/Aims: Accumulating evidence suggests that the use of NSAID may reduce the incidence of colorectal cancer. The likely mechanisms of these effects by NSAID is cyclooxygenase-2 (COX-2)-related inhibition of tumor proliferation and induction of apoptosis. The aim of our study was to examine possible roles and clinical significance of COX-2 expression in pancreatic cancer. Methods: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained from surgical resection. After the immunohistochemical staining of the specimens, we examined proliferation activity (assayed by Ki-67 expression), apoptosis (by TUNEL stain), and microvessel density (by CD34 expression). We also investigated the relationship between the immunohistochemical expression of COX-2 and various clinicopathological characteristics. Results: The COX-2 positive rate in pancreatic epithelial cells was 41.7%. Proliferation index (PI) was significant higher in COX-2 positive specimens comparing to negative specimen (p=0.015) and the increase in intensity of COX-2 expression correlated with increasing PI (p=0.036). Apoptotic index (AI) was significantly higher in positivee COX-2 expression than in negative expression (p=0.044), but there was no significant difference in AI/PI between the COX-2 positive and negative specimens (p=0.44). The expression of COX-2 protein did not correlate with microvessel density, sex, age, differentiation, tumor size, stage, metastasis or patients survival. Conclusions: The expression of COX-2 enzyme in pancreatic cancer contributes to tumor proliferation, but is not related to apoptosis, angiogenesis or clinical characteristics. Further study is needed to examine the clinical usefulness of NSAID and COX-2 selective inhibitors.

UO2 소결체에 고온연소반응을 이용한 SiC 코팅

김봉구,최용,김정원,이영우,손동성,김길무 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.5

Multi-layer coating of silicon carbide and graphite on UO₂ nuclear pellet was carried out with a fluidized bed type chemical vapor deposition unit to enhance the inherent safety of the nuclear pellet and to develop a renovative coating process. Silane, propane and argon gases were used as the source and carrier gases to deposit silicon and pyrolytic carbon. Combustion reaction was performed in an inert argon atmosphere, which conditions were pre-determined by numerical evaluation of the combustion reaction between silicon and carbon to synthesize silicon carbide. Microstructural observation of the combustion products by scanning electron microscopy showed that the inner and outer pyrolytic carbon layers were equiaxed structure. Chemical analysis by Auger electron spectroscopy and X-ray diffractometry revealed that the middle layer formed by a combustion reaction was fine crystalline beta-silicon carbide.

일별자료를 활용한 KOSPI 와 KOSDAQ 간의정보전달에 관한 실증 연구

김종출,황수석,김규호,신삼인 경남대학교 산업경영연구소 2019 지역산업연구 Vol.42 No.3

This paper studied the inter-relationship and market efficiency between KOSPI and KOSDAQmarket. The whole sample period is covered from January 4, 2000 to December 28, 2017. Weused the daily closing price data and trading volume of KOSDAQ and KOSPI. For these purposewe introduced Granger causality test based vector auto regressive analysis and the major empiricalresults are as follows;First, according to the unit root test, we find that the level variable and the log differencevariables are stationary with a statistically significant level. Second, we also find that there is a co-integration relationship between the level variables ofKOSPI and the KOSDAQ markets. Third, based on the Granger causality test, there is a feedback information transmissionbetween the returns of KOSDAQ and KOSPI but the impact of KOSPI is more dominant. Fourth, according to the impulse response analysis based on the vector auto regressive model,there is a similar relationship between the KOSPI and KOSDAQ returns. From these empirical results we infer that KOSPI is more efficient market than KOSDAQ andwe hope these results to helpful for the two market participants to make a investment decision andrisk management etc. 동 연구는 우리나라 KOSPI와 KOSDAQ에서의 일별 수익률과 거래 변화량 정보를 이용하여두 시장 간의 정보효율성에 대한 상호 인과관계를 여부를 분석하였다. 연구 기간으로는 2000년1월 4일부터 2017년 12월 28일까지이며, 총 4,446개의 KOSPI 및 KOSDAQ 일별 종가 자료와거래량 자료를 사용하였다. 연구 방법으로는 VAR모형에 기초한 그랜저(Granger) 인과관계 분석을 이용하였으며 주요 분석 결과는 다음과 같다. 첫째, KOSPI와 KOSDAQ의 수익률과 거래 변화량에 대한 분석을 위한 수준 변수와 차분 변수는 모두 안정적인 자료였으나, 상대적으로 차분 변수의 데이터가 보다 더 안정적인 자료로 나타나 차분변수를 활용하여 분석하였다. 둘째, KOSPI와 KOSDAQ의 각 변수 간에는 귀무가설이 통계적 유의한 수준에서 기각되었으며, 두 시장의 각 변수 간에는 장기적인 균형 관계가 존재함이 확인되었다. 셋째, VAR모형에 기초한 그랜저(Granger) 인과관계 분석결과, 두 시장의 수익률 간에는 상호영향을 미치는 피드백적인 영향이 있는 것으로 나타났으며, 그 영향의 크기는 KOSDAQ 수익률이 KOSPI 수익률에 미치는 영향력이 더 큰 것으로 나타났다. 넷째, 충격 반응에 대한 분석 결과에서는 KOSPI 수익률은 KOSDAQ 수익률에는 큰 영향을 받지 않는 것으로 나타났으나, KOSDAQ 수익률은 KOSPI 수익률과 자기 자신 모두에게 영향을 받는 것을 확인할 수 있었다. 이러한 분석 결과로 KOSPI와 KOSDAQ의 변동성은 KOSPI와 KOSDQ 두 시장 간에는 상호 영향을 미치는 피드백 적 영향을 미치고 있으며, 그 영향의 정도는 KOSPI가 KOSDAQ에 미치는 영향력이 상대적으로 더 큰 것을 확인할 수 있었다.

Glutaraldehyde 와 자동 세척기를 이용한 내시경 소독방법의 임상에서의 유용성

김영호,손희정,윤성원,최규완,이남용,백승운,이준행,고광철,이풍렬,이종철,송재훈,안병훈,김재준,최원혁,홍일철 대한소화기내시경학회 2001 Clinical Endoscopy Vol.22 No.6

Background/Aims: Safety of endoscopic procedures has been a major issue over the last 10 years. Most endoscopy units use 2% glutaraldehyde and automated endoscope reprocessors (AERs) for disinfecting gastrointestinal endoscopes. We attempted an in-use evaluation of the current reprocessing procedures. Methods: Thirty flexible endoscopes were randomly collected just after upper endoscopic examinations and were disinfected using 2% glutaraldehyde in an AER. Cultures were taken from biopsy channels (S-l), tip of the insertion tubes (S-2), umbilical cords (S-3), and angulation knobs (S-4). Results: In 63,3% (19/30) of endoscopes, there was no microbial contamination after disinfection procedures. The culture positive rates of S-l, S-2, S-3, and S-4 samples were 20,0%, 0.0%, 3.3%, and 20.0%, respectively. Microorganisms of 13 species were identified, but there was no pathogen related with reported infectious complications after endoscopic procedures. Conclusions: Current disinfection procedure using 2% glutaraldehyde and an AER appears to be very effective in decontaminating patient-used endoscopes. Low level microbial contamination of endoscopes after conventional reprocessing methods may not impose great risk on patients.

국내 통신사업자의 마케팅 핵심역량 분석 : 방법론 개발을 위한 접근

양유석,김영곤 정보통신정책학회 1999 정보통신정책연구 Vol.6 No.2

핵심역량이라는 용어가 활발하게 사용되고 있음에도 불구하고 학계에서의 실증적 연구는 상대적으로 미흡하다. 그 이유는 핵심역량 개념 자체가 산업특유성과 기업특유성을 가지고 있어 분석을 위해서는 기업의 내부정보를 필요로 하며 기업마다 핵심역량이 다르기 때문이다. 이러한 실증연구의 어려움을 극복하기 위한 방안으로 본 연구는 국내 통신사업자의 마케팅 관련 핵심역량을 추정하기 위해 각 기업의 핵심역량 구조는 동일하되 기업마다 역략 수준이 다를 것이며, 내부인사들의 평가나 외부전문가의 평가가 다르지 않을 것이라는 명제(proposition)을 가지고 접근하였다. 국내 유수의 통신기업 임원과 관련 학계 및 연구계의 전문가들을 대상으로 한 실증분석 결과는 본 연구의 명제가 틀리지 않은 것으로 나타났다. 따라서 앞으로 핵심역량과 관련한 실증적 연구의 활성화 가능성을 열어주는 계기가 될 것이다.

니세틸 정(아세틸 - 엘 - 카르니틴 500mg)에 대한 뉴로세틸 정의 생물학적 동등성

조혜영,오인준,이용복,임동구,문재동,심영순,김은아,정현철 한국약제학회 2001 Journal of Pharmaceutical Investigation Vol.31 No.1

Acetyl-L-carnitine (ALC), an endogenous component of the L-carnitine family, is naturally occurring molecule synthesized from L-carnitine (LC) by carnitine acetyl transferase. ALC has been shown to improve the cognitive performance of patients suffering from dementia of the Alzheimer's type and proposed for treating Alzheimer's disease in pharmacological doses. The purpose of the present study was to evaluate the bioequivalence of two ALC tablets, Nicetile^(TM) (Dong-A pharmaceutical Co., Ltd.) and Neurocetil^(TM) (Kyung-Dong Pharmaceutical Co., Ltd.), according to the guidelines of Korea Food and Drug Administration. Twenty six normal male volunteers, 22.80±2.76 year in age and 63.07±7.98 ㎏ in body weight, were divided into two groups and a randomized 2 × 2 cross-over study was employed. After one tablet containing 500 ㎎ of ALC was orally administered, blood was taken at predetermined time intervals and the concentrations of ALC in serum were determined using HPLC with fluorescence detector. Because of the presence of endogenous ALC, the calibration was performed using dialyzed serum. Pharmacokinetic parameters such as AUC_t, C_(max) and T_(max) were calculated and ANOVA was utilized for the statistical analysis of the parameters. The results showed that the differences in AUC_t, C_(max) and T_(max) between two tablets were 2.72%, -0.65% and -8.42%, respectively, when calculated against the Nicetile^(TM) tablet. The powers (1-β) for AUC_t and C_(max) were 94.87% and 87.17%, respectively. Minimum detectable differences (△) at α=0.05 and 1-β=0.8 were less than 20% (e.g., 15.58% and 19.16% AUC_t and C_(max), respectively). The 90% confidence intervals were within ±20% (e.g., -11.84∼6.41 and -10.57∼11.88 for AUC_t and C_(max), respectively). Two parameters met the criteria of KFDA for bioequivalence, indicating that Neurocetil^(TM) tablet is bioequivalent to Nicetile^(TM) tablet.

경대(經臺) 김상현(金尙鉉)의 교유시에 대한 일고찰

김용태 ( Kim Yong-tai ) 한국한문학회 2021 韓國漢文學硏究 Vol.- No.83

김상현은 19세기 중반 서울 문단의 중요한 작가였지만 안타깝게도 문집이 오늘날 전해지지 않고 있는 가운데, 그가 젊은 시절에 지은 시들을 모은 『경대시략』과 『경대시존』만전하고 있다. 본고는 이 자료를 통해 김상현의 교유시를 살펴보았다. 젊은 시절 김상현의 교유는 크게 ‘정약용 부자와의 교유’, ‘김매순과 홍석주 등 선배 문인과의 교유’, ‘윤종의와 박규수 등 동료 문인과의 교유’로 나누어 볼 수 있다. ‘정약용 부자와의 교유’에서는 김상현이 어떻게 당파가 다른 정약용에게서 가르침을 받을 수 있었는지 그 경위를 밝혔고, 어린 김상현의 눈에 정약용과 정학연이 어떠한 모습으로 비쳤는지를 살펴보았다. 이 부분은 향후 다산학단의 시문학 연구에 활용될 수 있을 것이다. ‘선배 문인과의 교유’에서는 ‘북촌 한문학’이 19세기 전반기 세대에서 중반기 세대로 이어지는 모습을 확인할 수 있었다. 김상현은 김매순, 이정리, 홍석주 등 선배들의 학문과 문학을 존경 어린 시선으로 증언하고, 선배들은 김상현을 격려하며 이끌어주었다. ‘동료 문인과의 교유’에서는 1840년 무렵 김상현이 동료 문인들과 매우 활발한 교유 활동에 나섰음을 확인하였다. 이 당시 이들의 움직임에서는 대단히 활기찬 에너지가 감지되는데, 끈끈한 동지적 결속을 바탕으로 미래에 대한 희망이 이들의 마음을 사로잡았던 것으로 보인다. 이 점은 문학사를 넘어 정치사에서도 주목할 지점이라고 생각되는바 향후 학계의 집중적인 연구가 이루어질 필요가 있다. Kim Sang Hyun is an important writer of Seoul literary circles in the mid-19th century, but unfortunately, his collection of literary works is not available today. However, the books of poetry he wrote when he was young, “Kyung Dae Si Ryak(經臺詩略)” and “Kyung Dae Si Jon(經臺詩存)” remain. Therefore, in this paper, I analyzed the poems he wrote while interacting with people, based on Kyung Dae Si Ryak and Kyung Dae Si Jon, which are the only materials that can examine the literary world of Kim Sang Hyun. Kim Sang Hyun’s social interaction in his youth can be divided into three categories: “interaction with Jeong Yak Yong’s family”, “interaction with senior writers such as Hong Seok Ju”, and “interaction with fellow writers such as Yoon Jong Eui and Park Kyu Soo”. In the chapter on “interaction with Jeong Yak Yong’s family”, I revealed how Kim Sang Hyun was able to be taught by Jeong Yak Yong of other factions. In addition, Kim Sang Hyun’s poems about Jeong Yak Yong’s family were examined to understand what the appearances of Jeong Yak Yong and Jeong Hak Yeon were reflected in the eyes of Kim Sang Hyun at that time. The contents in this chapter can be used for future study on literature of Dasan Academy. In the chapter on “interaction with senior writers”, it was possible to see how “Sino-Korean literature in Bukchon” was changing from the first half of 19th century to the mid-19th century. Kim Sang Hyun respected the studies and literature of his seniors such as Kim Mae Soon, Lee Jeong Ri, and Hong Seok Ju. Hence, the seniors encouraged and guided him. In the chapter on “interaction with fellow writers”, it was confirmed that Kim Sang Hyun had active interaction with many fellow writers around 1840, while he had mainly interacted with the Jeong Yak Yong family and senior writers before. This fellowship seems to come from the strong comradeship between young writers and their hope for the future. However, this atmosphere rapidly disappeared after the death of Heonjong of Joseon. This point should be noted not only in the history of literature, but also in the history of politics, and intensive research will be necessary for the future.

전후 한국시의 ‘현대성’과 그 계보적 가설 : 김종삼 시를 중심으로

김용희(Kim Yong-hee) 한국근대문학회 2009 한국근대문학연구 Vol.10 No.1

김종삼 시는 한국 현대시사에서 암시와 생략, 절제와 순수로 익히 정평이 나 있다. 이는 1950년대 한국 전쟁 상황이라는 비극적 인식 속에서 본질적 이념으로서의 기의를 상실한 채 시적 징후로서 현실을 형상화할 수밖에 없는 전후 시인들의 시대적 실어증을 내포하고 있다. 이는 김수영과 김춘수, 김종삼을 포함한 1950년대 문학인 전체에 해당하는 사안이다. 이들은 “외국어(일본어)로 사고하고 구성하고 모국어로 그것을 옮”겨야하는 불구적 창작방식의 세대였다. 유려한 리듬과 토속의 능숙한 구사를 원천적으로 제약당했던 세대가 민족 고유어나 민요를 계승할 수 없는 것은 당연한 일이었다. 박재삼이나 박용래와 같은 일부 시인을 제외하고 대부분 시인들이 모더니즘에 경사된 측면은 어쩌면 필연적이라 할 수 있다. 이 가운데서 김종삼은 비극적이고 황폐한 현실 인식, 가난과 소외와 죽음의식, 실존의 문제에 천착하면서 독자적인 시 형식을 보여준다. 불완전한 구문, 자주 급격히 끊어지는 리듬, 논리적 유추를 거부하는 생략과 비약, 여백들. 이는 ‘낡은 언어를 버리고 새로운 언어’를 찾고자 하는 시인의지이다. 세계 인간에 대한 부조리, 폐허 속에서의 부재의식, 피안-순수의 세계를 지향하고자 하는 초월적 낭만의지와 연관되며 릴케 영향 받은 후 실존주의에 대한 심취, 서양문화, 음악에 대한 경도와 연관된다. 이와같은 심취는 다시 미학적 시적 형식으로 육화된다. 1950년대 한국시 모더니즘은 1960년대에 안정적인 구도를 찾아간다고 할 수 있다. 한국시의 새로운 흐름은 소월, 만해에서 페시미즘과 토속적 초월주의, 미당의 전통설화에서의 민속주의, 청록파의 자연주의를 부정하면서 김수영, 김춘수라는 한국 모더니즘의 새로운 국면으로 접어든다. 김수영의 현실부정의 시학과 역동적 시적 주체의 문제, 김춘수의 언어실험 극단에 발생하는 도발적 이미지 충돌과 언어 본질 기능의 천착. 그 극단의 양 갈래 사이에 김종삼이 위치하는 것은 아닌가 한다. 김수영의 대사회적 삶의 태도, 김춘수의 역사허무주의 속에서 언어본질 탐구, 그 사이에 김종삼의 무정부주의적 삶의 한 단면을 생각해 볼 필요가 있다. 1960년대 한국 현대시 모더니티의 정착에서 새로움이 자아 인식, 개인의 발견, 일상적 개인의 추구라 한다면 김종삼 시는 지금까지 한국시에서 일찍이 볼 수 없었던 묘사적 ‘이미지를 통한 상징성’, 개성적 언어형식을 통한 ‘여백과 생략의 심미성’을 보여준다. Jongsam Kim's poetry is well-known for its suggestion, omission, temperance and genuineness in Korean modern poetry history. This has postwar poets' epochal aphasia of representing reality as poetic indication deprived of significance as the essential ideology, within the tragic recognition called Korean war in the 1950s. Such is a case relevant to the entire literary men in the 1950s, including Suyeong Kim, Chunsu Kim and Jongsam Kim. They were the generation of crippled creative method that conceived, composed in foreign language (Japanese) and then put into native language. It was a natural outcome for the generation, which was fundamentally constrained from having skillful command of elegant rhythm and folkways, to unable to inherit ethnic native tongue or folk song. Except for some poets like Jaesam Park or Yongrae Park, it was some what of perforce for most poets to show sides slanted towards Modernism. Jongsam Kim among them shows original poetry form by inquiring into recognition of tragic ruined reality, awareness of poverty, alienation and death, as well as the existent issues. Defective construction, frequent sudden breaks of rhythm, omission and leap refusing rational analogy, and blanks. These are the will of the poet to 'discard old language and search for new language'. After being influenced by Rilke in relation to transcendental romantic volition of heading towards absurdity for cosmopolitans, absent consciousness in the ruins and the world of Nirvana-purity, it was related to the fascination with existentialism, western culture and the degree of music. Such fascination is incarnated again into aesthetic poetry form. It can be said that Modernism of Korean poetry in the 1950s found its stable composition by the 1960s. From Sowol and Manhae, the new flow of Korean poetry approached the new aspect of Korean Modernism with Suyeong Kim and Chunsu Kim, by denying feminism; ethnic transcendentalism; ethnicism within traditional tale of Midang; and naturalism of the Cheongrokpa. Suyeong Kim's poetry of denying reality and theme of dynamic poetic subject, Chunsu Kim's collision of provocative imagery generated from the extreme language experiment and inquiry into the essential function of language. One thinks Jongsam Kim stands in the middle of the two extremes. It is necessary to think about one slice of Jongsam Kim's anarchistic life among Suyeong Kim's anti-social attitude to life and Chunsu Kim's investigation of linguistic essence seen in Historical Nihilism. When the recency was pursuing self-perception, discovery of individuals and ordinary individual in the modernity of Korean modern poetry in the 1960s, Jongsam Kim's poetry shows depictive 'symbolism through imagery' which was never seen in Korean poetry before as well as 'aesthetic appreciation for blank and omission' through his unique linguistic form.

A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea

Yong Sung Choi,정성훈,김은선,Eun Sun Kim,Eunhee Lee,Euiseok Jung,So-Yeon Lee,이우령,Hye Sun Yoon,Yong Joo Kim,Ji Kyoung Park,Son Moon Shin,Ellen Ai-Rhan Kim 대한신생아학회 2022 Neonatal medicine Vol.29 No.1

Purpose: Pediatricians have a significant responsibility to educate mothers about the importance of breastfeeding. However, there have been minimal efforts in the courses of resident training in Korea. The purpose of this study is to evaluate the change in knowledge and attitude before and after a 4-week breastfeeding educational intervention among multicenter residents. Methods: Prospective interventional educational research was designed for residents at eight training hospitals in Korea. Institutional reviews were obtained in each hospital. The education curriculum consisted of 14 courses regarding breastfeeding theory and practice. These materials were used to teach pediatric residents for 4 weeks. Knowledge-based tests were administered before the course, and re-tests were administered after the course using different test items of similar levels. Test scores and survey responses were compared before and after the intervention. Results: A total of 73 residents (1st year 20, 2nd year 23, 3rd year 16, and 4th year residents 14) from eight training hospitals completed the intervention. Their average age was 30.3±2.9 years, 17 (23.3%) were male, 22 (30.1%) were married, and eight had more than one child of their own. The mean pre-test score was 61.8±13.4 and the mean post-test score was 78.3±7.5 (P<0.001). The inter-grade difference in the score was significant in the pre-test (P=0.005), but not significant in the post-test (P=0.155). There were more responses of obtaining confidence after the intervention (P<0.001). Conclusion: In our study, pediatric residents showed improvement in their knowledge and confidence level after 4 weeks of the breastfeeding curriculum. This will provide a basis for future policymaking in the training of pediatric residents regarding breastfeedReceived: 6 January 2022 Revised: 15 February 2022 Accepted: 15 February 2022 Correspondence to: Ellen Ai-Rhan Kim, MD Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Tel: +82-2-3010-3390 Fax: +82-2-3010-6978 E-mail: arkim@amc.seoul.kr A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea Yong-Sung Choi, MD,PhD1, Sung-Hoon Chung, MD, PhD2, Eun Sun Kim, MD, PhD3, Eun Hee Lee, MD4, Euiseok Jung, MD5, So Yeon Lee, MD, PhD5, Wooryoung Lee, MD6, Hye Sun Yoon, MD, PhD7, Yong Joo Kim, MD, PhD8, Ji Kyoung Park, MD, PhD9, Son Moon Shin, MD, PhD9, and Ellen Ai-Rhan Kim, MD, PhD5 1Department of Pediatrics, Kyung Hee University Hospital, Seoul, Korea 2Department of Pediatrics, Kyung Hee University Hospital at Gangdong, Seoul, Korea 3Department of Pediatrics, Kangwon National University Hospital, Chuncheon, Korea 4Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea 5Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 6Department of Pediatrics, Soonchunhyang University Seoul Hospital, Seoul, Korea 7Department of Pediatrics, Nowon Eulji Medical Center, Eulji University, Seoul, Korea 8Department of Pediatrics, Hanyang University Seoul Hospital, Seoul, Korea 9Department of Pediatrics, Inje University Busan Paik Hospital, Busan, Korea Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 pISSN 2287-9412 . eISSN 2287-9803 Copyright(c) 2022 By Korean Society of Neonatology This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Original Article 29 Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 ing in Korea.