전염병 유행 단계별 인간 이동패턴과 COVID-19 전염병 확산의 역학관계 분석: 서울시를 중심으로

오현근(Hyunkeun Oh),김민경(Minkyoung Kim) 한국정보기술학회 2023 한국정보기술학회논문지 Vol.21 No.4

As COVID-19 dominates our lives, there has been a wide spectrum of research to predict infectious disease spread. However, it has not been relatively paid attention to study dynamics of disease spread with long-term human mobility, particularly for domestic cases. In this regard, this study aims to analyze long-term human mobility in Seoul to understand underlying dynamics of COVID-19 propagation and obtain insights. As a result, the correlation between the numbers of residents and confirmed cases increases as the epidemic stage progresses, showing that confirmed cases gradually follow a uniform distribution across regions, regardless of regional features. Additionally, regular movement plays a crucial role in the propagation of COVID-19 in Seoul. We expect that this study can shed light on understanding emergent phenomena across a heterogeneous social system from spatiotemporal data.

Gadoteridol을 이용한 Head & Neck MR Angiography에서의 적정 Flip Angle

정현근(Hyunkeun Jeong),김민기(Mingi Kim),송재준(Jaejun Song),남기창(Kichang Nam),최현성(Hyunsung Choi),정현도(Hyundo Jeong),김호철(Hochul Kim) 대한전자공학회 2016 전자공학회논문지 Vol.53 No.3

본 연구의 목적은 가돌리늄 조영제를 사용한 Head & Neck MR Angio검사에 있어서 매개변수인 FA(Flip Angle)이 MR신호에 미치는 영향에 대해서 알아보고자 하였으며, 이에 따른 FA의 적정 값을 제시하는 것이다. 실험은 FA증가에 따른 MR팬텀실험과 임상실험으로 진행하였고, 이에 대한 정량적 분석이 이루어졌다. 실험결과 팬텀실험에서의 조영증강 반응시작 지점인 RSP(Reaction Starting Point)는 FA증가에 따라 300∼400 m㏖ 사이에서 반응하였고, 최대 신호강도인 MPSI(Max Peak Signal Intensity)는 2,086, 3,705, 5,109, 6,194, 7.096, 7,192 [a.u]를 기록하였다. MPSI가 형성되는 몰농도 지점인 MPP(Max Peak Point)는 FA에 증가에 따라 40, 50, 50, 40, 50, 40 mmol에서 보였으며, MPSI의 증가율인 IRMPSI(Increase Rate of MPSI)는 77.6%, 37.9%, 21.2%, 14.6%, 1.4%임을 확인하였다. 임상실험에서의 평가기준인 SICB(Signal Intensity of Carotid artery Bifurcation)는 FA증가에 따라 각 평균값 2392.5, 4165.2, 4270, 3502.2, 3263.7, 3119.6 [a.u]를 기록하였고, 아티팩트 발생율인 ORA(Occurence Rate of Artifact)는 0, 0, 20, 40, 50, 70%로 점차 증가하였다. 본 연구를 통하여 FA의 증가는 혈관 내가돌리늄과 결합한 H1스핀의 신호강도와 아티팩트에 영향을 미친다는 사실을 확인하였고, 이는 실제 임상에서의 CE(Contrast Enhanced)-Head&Neck MR Angio검사에 있어서 본 연구의 데이터를 활용한다면 진단학적으로 효율적인 MR Angiography 영상을 구현할 수 있을 것으로 사료된다. In this research, we tried to suggest moderate FA(Flip Angle) for CE(Contrast Enhnaced)-Head&Neck MR Angiography with Gadoteridol. For this study, we did test MR phantom and clinical study according to FA change. After that, quantitative analysis was progressed. The results of MR phantom study were as follow: RSP(Reaction Starting Point)was recorded within 300∼400 m㏖. MPSI(Max Peak Signal Intensity) was 2,086, 3,705, 5,109, 6,194, 7.096, 7,192 [a.u]. MPP(Max Peak Point) was shown at 30, 50, 50, 40, 50, 40 mmol. IRMPSI(Increase Rate of MPSI) was 77.6%, 37.9%, 21.2%, 14.6%, 1.4% as increasing of FA. The results of clinical study were as follow SICB(Signal Intensity of Carotid artery Bifurcation) was recorded respectively 392.5, 4165.2, 4270, 3502.2, 3263.7, 3119.6 [a.u]. ORA(Occurence Rate of Artifact) was increased as 0, 0, 20, 40, 50, 70%. According to this research, we are not only able to assure that increase of FA can be effect on H1 spin"s SI(Signal Intensity) which was combined with gadolinium agent, but also be effect on artifact rate in blood vessel. In clinical field, we expect that CE-Head&Neck MR Angiography can be performed in a practical way with this research.

Lon-Mediated Proteolysis of the FeoC Protein Prevents <i>Salmonella enterica</i> from Accumulating the Fe(II) Transporter FeoB under High-Oxygen Conditions

Kim, Hyunkeun,Lee, Hwiseop,Shin, Dongwoo American Society for Microbiology 2015 Journal of Bacteriology Vol.197 No.1

<P>The <I>Salmonella</I> Feo system consists of the FeoA, FeoB, and FeoC proteins and mediates ferrous iron [Fe(II)] import. FeoB is an inner membrane protein that, along with contributions from two small hydrophilic proteins, FeoA and FeoC, transports Fe(II). We previously reported that FeoC binds to and protects the FeoB transporter from FtsH-mediated proteolysis. In the present study, we report proteolytic regulation of FeoC that occurs in an oxygen-dependent fashion. While relatively stable under low-oxygen conditions, FeoC was rapidly degraded by the Lon protease under high-oxygen conditions. The putative Fe-S cluster of FeoC seemed to function as an oxygen sensor to control FeoC stability, as evidenced by the finding that mutation of the putative Fe-S cluster-binding site greatly increased FeoC stability under high-oxygen conditions. <I>Salmonella</I> ectopically expressing the <I>feoB</I> and <I>feoC</I> genes was able to accumulate FeoB and FeoC only under low-oxygen conditions, suggesting that FeoC proteolysis prevents <I>Salmonella</I> from accumulating the FeoB transporter under high-oxygen conditions. Finally, we propose that Lon-mediated FeoC proteolysis followed by FtsH-mediated FeoB proteolysis helps <I>Salmonella</I> to avoid uncontrolled Fe(II) uptake during the radical environmental changes encountered when shifting from low-iron anaerobic conditions to high-iron aerobic conditions.</P>

The FeoC Protein Leads to High Cellular Levels of the Fe(II) Transporter FeoB by Preventing FtsH Protease Regulation of FeoB in <i>Salmonella enterica</i>

Kim, Hyunkeun,Lee, Hwiseop,Shin, Dongwoo American Society for Microbiology 2013 Journal of Bacteriology Vol.195 No.15

<P>In the gammaproteobacteria, the FeoA, FeoB, and FeoC proteins constitute the Feo system, which mediates ferrous iron [Fe(II)] import. Of these Feo proteins, FeoB is an inner membrane Fe(II) transporter that is aided by the small protein FeoA. However, the role of another small protein, FeoC, has remained unknown. Here we report that the FeoC protein is necessary for FeoB protein-mediated Fe(II) uptake in <I>Salmonella</I> experiencing low levels of oxygen and iron. The FeoC protein was found to directly bind to the FeoB transporter, leading to high cellular levels of FeoB. Depletion of the FtsH protease enabled high levels of FeoB in the absence of FeoC, suggesting that the FeoC protein protects the FeoB transporter from FtsH-mediated proteolysis. Our present study provides a singular example of bacteria that can control expression of iron uptake systems posttranslationally by employing a small iron transporter-binding protein.</P>

초미세발포 사출 성형 성형공정을 이용한 유리섬유 보강 플라스틱의 소진 진동 응답 특성 연구

김현근(Hyunkeun Kim),차성운(Sungwon Cha) 한국자동차공학회 2021 한국자동차공학회 학술대회 및 전시회 Vol.2021 No.11

3.0T MRI 장비 종류에 따른 Gadoteridol의 반응 분석

정현근(Hyunkeun Jeong),김민기(Mingi Kim),남기창(Kichang Nam),김현종(Hyunjong Kim),김호철(Hochul Kim) 대한전자공학회 2019 전자공학회논문지 Vol.56 No.6

본 연구에서는 동일한 3.0T 자장 세기에서 다양한 MRI 모델에 따른 가도테리돌의 반응정도를 정량화하고자 하였다. 이를 위하여 0.5 mol 가돌리늄 조영제인 가도테리돌 MR팬텀을 제작하여, 임상에서 사용 중인 각각 다른 종류의 3.0T MRI장비를 활용하여 실험 및 분석을 진행하였다. 팬텀실험결과 750w, Archeiva, Skyra 각 장비에서의 RSP는 20, 20, 50 mmol로 기록되었고, MPSI는 1377, 1495, 3459 [a.u.]를 보였다. MPP는 0.8, 0.6, 4 mmol로 기록되었고, CPFS는 276.3, 716.7, 287.3 [%]를 보였다. EPMF는 96.7, 47.6, 69.1[%]를 각각 기록하였고, EPMS는 640.3, 1105.6, 555.1 [%]를 보였다. 본 연구를 통하여 동일한 3.0T의 자장세기라 하더라도, 장비 모델에 따라 가도테리돌에 대한 반응이 모두 상이하다는 것을 확인 할 수 있었다. 이에 따라 임상현장에서 MRI 장비종류에 따른 GBCA반응정도를 정량화하여 사용한다면, 진단학적으로 더 유용한 조영증강 검사가 가능하다고 사료된다. In this study, we tried to quantify the response of Gadoteridol to various MRI models at the even same 3.0T magnetic field strength. To do this, MR phantom made with 0.5 mol of Gadoteriol was prepared and the experiment were conducted by using 3.0T MRI equipment of each different company in clinical field. We obtained the following results in each 750w, Archeiva, and Skyra devices: RSP was recorded at 20, 20, and 50 mmol and the MPSI showed 1377, 1495, and 3459 [a.u.]. MPP was recorded at 0.8, 0.6, and 4 mmol, and CPFS was 276.3, 716.7, and 287.3 [%]. EPMF recorded 96.7, 47.6 and 69.1 [%] respectively, and EPMS showed 640.3, 1105.6 and 555.1 [%]. By this study, we confirmed that the response of Gadoteridol is different according to the equipment model at the even same magnetic field strength of 3.0T. Therefore, if we quantify the degree of GBCA response according to the type of MRI equipment in the clinical field, it is considered that a more useful diagnostic MRI scan for enhancement is possible.

3.0T MRI DWI EPI시퀀스에서의 Gadoteridol반응 분석

정현근(Hyunkeun Jeong),남기창(Kichang Nam),김호철(Hochul Kim) 대한전자공학회 2018 전자공학회논문지 Vol.55 No.4

본 연구에서는 DWI(Diffusion Weighted Image) EPI(Echo Planar Image)시퀀스 에서의 GBCA(Gadolinium Based Contrast Agent)반응유무와 그 정도를 정량화하고자 하였다. 이를 위하여 MR 가돌리늄 조영제인 0.5 mol Gadoteridol로 제작된 MR팬텀을 활용하여, 3.0T MRI장비에서 실험을 진행하였다. 이에 따른 결과는 다음과 같다. RSP(Response Start Point): 8 [mmol], MPSI(Max Peak Signal Intensity): 2086 [a.u], MPP(Max Peak Point): 0.6 mmol, FWSI(Free Water"s SI): 1160 [a.u], ASIM(Average SI on each Mol): 6∼2086 [a.u], RSPE(RSP base on Epmf): 1 [mmol], EPMF(Enhancement Percentage on each Mol based on Free water): -99∼+ 101%, AEPMF(Average of EPMF): -99∼80%. 본 연구를 통하여 DWI EPI시퀀스에서 GBCA가 반응한다는 사실과 그 정량화 데이터를 확인 할 수 있었다. In this study, we tried to quantify the presence or absence of reaction and degree of GBCA (Gadolinium Based Contrast Agent) in DWI (Diffusion Weighted Image) echo planar image (EPI) sequences. For this purpose, the MR phantom made with 0.5 mol Gadoteridol, an MR gadolinium contrast agent, was used in the 3.0T MRI system. Obtained the following results ; RSP(Response Start Point): 8 [mmol], MPSI(Max Peak Signal Intensity): 2086 [a.u], MPP(Max Peak Point): 0.6 mmol, FWSI(Free Water"s SI): 1160 [a.u]. ASIM(Average SI on each Mol): 6∼2086 [a.u] , RSPE(RSP base on Epmf): 1 [mmol], EPMF(Enhancement Percentage on each Mol based on Free water): -99∼+ 101%, AEPMF(Average of EPMF): -99∼80%. Through this study, we could confirms the fact that GBCA responds to the DWI EPI sequence and its quantification data.

MRI에서 TI 변화에 따른 지방소거 정도에 대한 정량적 분석

정현근(Hyunkeun Jeong),김민기(Mingi Kim),남기창(Kichang Nam),이승묵(Seungmook Lee),강충환(Chunghwan Kang),김성호(Sungho Kim),이기백(Kibaek Lee),조용범(Yongbum Cho),김호철(Hochul Kim) 대한전자공학회 2018 전자공학회논문지 Vol.55 No.3

본 연구에서는 MRI검사에 사용되는 IR(Inversion Recovery)시퀀스에서 TI(Time to Inversion)변화에 따른 지방소거정도를 정량화 하고자 하였다. 이를 위하여 체내 구성 물질을 재현하기 위한 fat, water, tissue로 구성된 MR팬텀을 제작하였고, 이를 임상에서 사용 중인 1.5T MRI장비를 활용하여 실험 및 분석을 진행하였다. 팬텀실험결과 Fat SI는 67∼1291[a.u]사이에서 신호강도가 형성되었으며, Water SI는 676∼1221[a.u], Tissue SI는 76∼750[a.u]사이에서 신호강도를 보였다. 이에 따른 EPFW(Enhancemet Percentage of Fat to Water)는 -78∼94% 사이에서 분포를 보였고, EPFT(Enhancement Percentage of Fat to Tissue)는 -632∼73%, EPWT(Enhancement Percengage of Water to Tissue)는 45∼93% 사이에서 대조도가 형성되는 것을 확인하였다. 실험을 통하여 IR 시퀀스 사용 시 가장 효과적인 지방소거를 위한 TI 파라메타는 140msec였으며, 이때 지방 신호가 가장 최저로 감소하고 더불어 주변조직과의 대조도가 가장 크게 형성되어 있음을 확인 할 수 있었다. 이에 따라 임상현장에서 본 연구의 각각의 물질별 신호변화 정량화 데이터를 활용하여 TI범주를 적용한다면, 목적에 부합하는 적정한 진단학적 영상을 얻을 수 있을 것으로 사료된다. In this study, we tried to quantify the degree of fat saturation by changing the TI (Time to Inversion) in the Inversion Recovery (IR) sequence used for MRI. For this purpose, MR phantom composed of fat, water, and tissue was prepared to reproduce the constituent materials in the body, and the experiment and analysis were conducted using the 1.5T MRI equipment in clinical field. Phantom test results showed that signal intensity of Fat SI was between 67∼1291 [a.u], water SI was between 676∼1221 [a.u] and Tissue SI was between 76∼750 [a.u]. EPFW (Enhancement Percentage of Fat to Water) was distributed between -78 and 94%, EPFT (Enhancement Percentage of Fat to Tissue) was -632 to 73%, EPWT (Enhancement Percentage of Water to Tissue) was 45∼93%. Experimental results showed that the most effective fat saturation TI parameter for IR sequences was 140 msec. At this time, the fat signal was the lowest and the contrast with the surrounding tissues was the greatest. Therefore, if the TI range is applied by using quantitative data of signal changes of each substance in the clinical field, it is considered that appropriate diagnostic images corresponding to the purpose can be obtained.

Transforming growth factor-β1 regulates human renal proximal tubular epithelial cell susceptibility to natural killer cells via modulation of the NKG2D ligands

SONG, HYUNKEUN,KIM, YEONYE,PARK, GABIN,KIM, YEONG-SEOK,KIM, SEONGHAN,LEE, HYUN-KYUNG,CHUNG, WOO YEONG,PARK, SEOK JU,HAN, SANG-YOUB,CHO, DAEHO,HUR, DAEYOUNG UNKNOWN 2015 INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE Vol.36 No.4

사운드 소스 기반 머신러닝을 이용한 차량용 진단 시스템 설계

김현근(Hyunkeun Kim),손주성(Joo Seong Sohn),유영재(Youngjae Ryu),차성운(Sung Woon Cha) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5