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The Evolving Policy Debate on Border Closure in Korea
Su-Jin Kang,Jihyun Moon,Heewon Kang,Heekyoung Nam,Sangwoo Tak,Sung-Il Cho 대한예방의학회 2020 Journal of Preventive Medicine and Public Health Vol.53 No.5
302 Copyright © 2020 The Korean Society for Preventive Medicine J Prev Med Public Health 2020;53:302-306 • https://doi.org/10.3961/jpmph.20.213 The Evolving Policy Debate on Border Closure in Korea SuJin Kang1, Jihyun Moon2, Heewon Kang1, Heekyoung Nam3, Sangwoo Tak1, Sung-il Cho1,3 1Institute of Health and Environment, Seoul National University, Seoul, Korea; 2Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul, Korea; 3Department of Public Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, Korea Brief Report Objectives: In this paper, we aimed to investigate the evolving debate over border closure in Korea during the coronavirus disease 2019 (COVID-19) pandemic, to address the main themes associated with border closure, and to discuss the factors that need to be considered when making such decisions. Methods: We collated and reviewed previously conducted review studies on border closures during infectious disease outbreaks to derive relevant themes and factors. Results: According to our systematic review on border closures and travel restrictions, the effects of such containment efforts are limited. We suggest considering the following factors when determining whether to impose border closure measures: (1) disease characteristics, (2) timeliness of implementation, (3) transmission delay and the basic reproduction number, (4) globalization and pandemics, and (5) social and economic costs. Conclusions: Our assessment indicates that the effects of border closures are at best temporary and limited. Alternative measures must be contemplated and implemented to suppress the spread of COVID-19 in particular and infectious diseases more broadly.
Food Source Analysis of Rattus norvegicus, a Coinhabitant of Marine Birds in South Korea
Kang, Jihyun,Cha, Hyoun-Gi,Shin, Hyun Chul,Lee, Yunkyong,No, Doory,Kim, Wooyoung,Eum, Soon Jae National Institute of Ecology 2022 국립생태원회보(PNIE) Vol.3 No.3
The Chinese crested tern (Thalasseus bersteini) is one of the most globally endangered species, listed as "Critically Endangered (CE)" on the IUCN Red List, with only approximately 30-49 individuals surviving in the wild. Chinese crested terns were discovered to breed in South Korea for the first time in 2016 while conducting a census on uninhabited islands. The Ministry of Environment has declared the breeding habitat of the Chinese crested terns as "Specified Island" to protect this CE species. However, brown rats (Rattus norvegicus) inhabiting the breeding grounds of the Chinese crested terns and Black-tailed gulls may potentially pose a threat to the breeding of these avian species. Therefore, we conducted a study on the feeding behavior of brown rats involving stable isotope analysis to determine their food sources. Fecal analysis showed that brown rats mainly fed on plants, whereas they scarcely fed on animals, such as insects. In addition, the stable isotope analysis showed that the δ<sup>13</sup>C values of brown rats, insects, and Indian goosegrasses were approximately -16 to -11‰, whereas the δ<sup>13</sup>C value of Chinese crested terns that obtained their food from the marine ecosystem was approximately -22 to -18‰. Hence, we conclude that the source of carbon for brown rats on this island is the terrestrial ecosystem. We ruled out the possibility of any direct prey-predator interaction between the brown rat and the Chinese crested tern or Black-tailed gull.
( Jihyun An ),( Hyo Jeong Kang ),( Ju Hyun Shim ),( Gi-won Song ),( Gwang Hyun Choi ),( Han Chu Lee ),( Bora Oh ),( Naomi Park ),( Jihyun ),( Song Eunsil Yu ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1
Aims: Immune checkpoint proteins regulating T-cell mediated anti-tumor immunity have been reported to affect clinical outcomes in multiple malignancies. This study aimed to investigate the prognostic effect of histological expression of immune checkpoint proteins in patients with resected hepatocellular carcinoma (HCC). Methods: A total of 221 patients with HCC who underwent curative resection were included. Expression of Programmed-cell death ligand- 1 in tumor cells (tPD-L1) and tumor infiltrating mononuclear cells (TIMCs) (iPD-L1), Programmed-cell death-1 in TIMCs (iPD-1), and cytotoxic T lymphocyte antigen-4 in TIMCs (iCTLA-4) were measured immunohistochemically. Results: Among the 221 patients, histo-positivity for iCTLA-4, iPD-1, iPD-L1, and tPD-L1 was 32.1% (n=71), 42.5% (n=94), 35.3% (n=78), and 14.9% (n=33), respectively. Multivariate logistic analyses revealed that male sex and tumor >5cm were variables related to iCTLA-4 positivity (odds ratios [ORs] 0.46 and 1.94 respectively; Ps<0.05). Poor differentiation was related to PD-L1 expression in both tumor cells and TIMCs (ORs 2.88 and 3.46, respectively; Ps<0.05). Microvascular invasion was significantly associated only with iPD-L1, whereas tPD-L1 was positively correlated with baseline elevation of serum alpha-fetoprotein (≥200 ng/ml) (ORs 2.24 and 2.45; Ps<0.05). In time-dependent outcome analyses, expression of immune checkpoint proteins in TIMCs (i.e., iCTLA-4, iPD-1, and iPD-L1) was significantly related to longer overall survival and non-cancer-related survival (all Ps< 0.05), but not to time-to-recurrence or cancer-specific deaths (all Ps >0.05). Concurrent activation of the PD-1:PD-L1 and CTLA-4 pathways predicted improved outcomes in terms of overall survival and non-cancer related survival (P=0.06 and P=0.03, respectively). Conclusions: Immune checkpoint proteins upregulated in TIMCs in HCC tissues have individual and additive effects in prolonging the survival of patients, specifically in terms of survival not related to cancer recurrence.
Jihyun Won,Juhyung Kang,Wonyoung Park,José C. J. M. D. S. Menezes,Marc Diederich,Eunyoung Kim,Wonku Kang 한국분석과학회 2023 분석과학 Vol.36 No.1
2’-Hydroxy-3’,4’-methylenedioxy-3,4,5-trimethoxychalcone (HMTC) is a newly synthesized chalcone that affects proliferation, cytotoxic potential and apoptosis in human leukemia cells. However, no validated determination method has been described so far for HMTC in biological samples. Thus, we developed a liquid chromatographic method using a tandem mass spectrometry to determine HMTC in rat plasma. Liquid-liquid extraction with ethyl acetate was used for the clean-up procedure. The analyte was separated on a reversedphase column with mobile phase of distilled water and acetonitrile (2:8, v/v, including 0.1 % formic acid). The ion transition of the precursor to the product ion was principally deprotonated ions [M-H]− at m/z 356.8 → 327.2 for HMTC. This analytical method was successfully applied in pharmacokinetic study of HMTC after intravenous administration in rats.
Nucleic Acid-Scavenging Electrospun Nanofibrous Meshes for Suppressing Inflammatory Responses
Kang, Jihyun,Yoo, Hyuk Sang American Chemical Society 2014 Biomacromolecules Vol.15 No.7
<P>Fragmented nucleic acids are potent stimulators for inflammatory responses provoking pathological outcomes by activating adaptive immunity. In this study, highly cationic surfaces were prepared on electrospun nanofibrous meshes to scavenge nucleic acids to the surfaces. Poly(ε-caprolactone) [PCL]-poly(ethylenimine) [PEI] block copolymers were synthesized by coupling the carboxyl-terminated PCL to the primary amines of branched PEI. Polymeric solutions composed of PCL–PEI and PCL were electrospun to nanofibrous mats, and the surfaces were further methylated to prepare highly cationic surfaces on the mats. Raman spectroscopy revealed that the presence of increased methylated amines on the surfaces of the mats compared to unmodified mats. The methylated surfaces showed significant increases of wettability after methylation, suggesting highly charged surfaces caused by methylation of the primary amines. When the blend ratio of PCL–PEI was increased, the scavenged DNA was also increased, and the methylation further strengthened the scavenging ability of the mats. Fluorescently labeled oligodeoxynucleic acids were significantly adsorbed on the surface of the mats depending on the amounts of PCL–PEI and the degree of methylation. In the presence of the methylated nanofibrous mats, inflammatory responses induced by CpG oligonucleotides in murine macrophages were significantly reduced, which was confirmed by measuring inflammatory cytokine levels including TNF-α and IFN-γ.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bomaf6/2014/bomaf6.2014.15.issue-7/bm500437e/production/images/medium/bm-2014-00437e_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/bm500437e'>ACS Electronic Supporting Info</A></P>
( Jihyun Yu ),( Sojin Ahn ),( Kwondo Kim ),( Kelsey Caetano-anolles ),( Chanho Lee ),( Jungsun Kang ),( Kyungjin Cho ),( Sook Hee Yoon ),( Dae-kyung Kang ),( Heebal Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8
As probiotics play an important role in maintaining a healthy gut flora environment through antitoxin activity and inhibition of pathogen colonization, they have been of interest to the medical research community for quite some time now. Probiotic bacteria such as Lactobacillus plantarum, which can be found in fermented food, are of particular interest given their easy accessibility. We performed whole-genome sequencing and genomic analysis on a GB-LP1 strain of L. plantarum isolated from Korean traditional fermented food; this strain is well known for its functions in immune response, suppression of pathogen growth, and antitoxin effects. The complete genome sequence of GB-LP1 is a single chromosome of 3,040,388 bp with 2,899 predicted open reading frames. Genomic analysis of GB-LP1 revealed two CRISPR regions and genes showing accelerated evolution, which may have antibiotic and antitoxin functions. The aim of the present study was to predict strain specific-genomic characteristics and assess the potential of this new strain as lactic acid bacteria at the genomic level using in silico analysis. These results provide insight into the L. plantarum species as well as confirm the possibility of its utility as a candidate probiotic.
누리온 시스템에서의 All-Reduce 알고리즘 성능평가
명훈주 ( Hunjoo Myung ),정기문 ( Kimoon Jeong ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2
GPU 기술과 빅데이터의 성장에 힘입어 최근 딥러닝 기술은 괄목할만한 성장을 이루었고, 구글, 페이스북, 우버 등의 빅데이터를 보유한 업체들과 슈퍼컴퓨팅분야에서는 이러한 빅데이터를 빠른 시간 안에 학습하기 위해 분산 딥러닝 기술을 연구해오고 있다. 이러한 대규모 분산 딥러닝에서는 집합 통신, IO 부하 등이 주요 병목으로 알려져 있다. 본 연구에서는 분산 딥러닝에서 시도되고 있는 주요 All-Reduce 알고리즘들에 대해 누리온 시스템에서 성능평가를 수행하였고, 512노드 이상의 대규모에서는 2D-torus 알고리즘이 우수한 성능을 보였다.