Microfluidic platform for single cell analysis under dynamic spatial and temporal stimulation

Song, Jiyoung,Ryu, Hyunryul,Chung, Minhwan,Kim, Youngtaek,Blum, Yannick,Lee, Sung Sik,Pertz, Olivier,Jeon, Noo Li Elsevier 2018 Biosensors & bioelectronics Vol.104 No.-

<P><B>Abstract</B></P> <P>Recent research on cellular responses is shifting from static observations recorded under static stimuli to real-time monitoring in a dynamic environment. Since cells sense and interact with their surrounding microenvironment, an experimental platform where dynamically changing cellular microenvironments should be recreated <I>in vitro</I>. There has been a lack of microfluidic devices to support spatial and temporal stimulations in a simple and robust manner. Here, we describe a microfluidic device that generates dynamic chemical gradients and pulses in both space and time using a single device. This microfluidic device provides at least 12h of continuous stimulations that can be used to observe responses from mammalian cells. Combination of the microfluidic de­vice with live-cell imaging facilitates real-time observation of dynamic cellular response at single cell level. Using stable HEK cells with biosensors, ERK (Extracellular signal-Regulated Kinase) activities were observed un­der the pulsatile and ramping stimulations of EGF (Epidermal Growth Factor). We quantified ERK activation even at extremely low EGF concentration (0.0625µg/ml), which can not be observed using conventional techniques such as western blot. Cytoskeleton re­arrangement of the 3T3 fibroblast (stable transfection with Lifeact-GFP) was compared under abrupt and gradually changing gradient of PDGF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A long-term live cell monitoring was performed under the spatial and temporal dynamic stimulations. </LI> <LI> Versatile stimulation profiles were generated in a single device without further modification. </LI> <LI> Quantitative observation of the persistent ERK activation with the increasing concentrations of EGF was made initially. </LI> <LI> Prior to the development of our device, ramping down stimulation of certain matters was unable to be achieved. </LI> <LI> Dynamically changing gradients were proposed and can be applied in directed cell migration. </LI> </UL> </P>

AI

Jiyoung Song(송지영) 한국디자인학회 2018 한국디자인학회 국제초대전도록 Vol.2018 No.11

Consideration of NOACs (novel or non-vitamin K-dependent oral anticoagulants) in dental procedure

Jiyoung Song 대한구강악안면외과학회 2021 대한구강악안면외과학회지 Vol.47 No.6

Study of Peak Load Demand Estimation Methodology by Pearson Correlation Analysis with Macro-economic Indices and Power Generation Considering Power Supply Interruption

Jiyoung Song,Jaegul Lee,Taekyun Kim,Yongbeum Yoon 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4

Since the late 2000s, there has been growing preparation in South Korea for a sudden reunification of South and North Korea. Particularly in the power industry field, thorough preparations for the construction of a power infrastructure after reunification are necessary. The first step is to estimate the peak load demand. In this paper, we suggest a new peak demand estimation methodology by integrating existing correlation analysis methods between economic indicators and power generation quantities with a power supply interruption model in consideration of power consumption patterns. Through this, the potential peak demand and actual peak demand of the Nation, which experiences power supply interruption can be estimated. For case studies on North Korea after reunification, the potential peak demand in 2015 was estimated at 5,189 MW, while the actual peak demand within the same year was recorded as 2,461 MW. The estimated potential peak demand can be utilized as an important factor when planning the construction of power system facilities in preparation for reunification.

Analysis of Hazard Scenario of Nuclear Facility for Preparation of Radiological Environmental Impact Assessment Report (RER)

Jiyoung Song,Jongjin Kim 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.06

FBDTester 2.0: Automated test sequence generation for FBD programs with internal memory states

Song, Jiyoung,Jee, Eunkyoung,Bae, Doo-Hwan Elsevier 2018 Science of computer programming Vol.163 No.-

<P><B>Abstract</B></P> <P>As Function Block Diagram (FBD) programs are used to implement safety-critical systems such as nuclear reactor protection systems, it is crucial to generate effective test cases. FBD programs are running on programmable logic controllers (PLCs) that execute the programs repeatedly within a particular scan time. Among the elements of FBD programs, function blocks and feedback variables save the inputs or outputs of the previous scan cycle into internal memories. The data stored in the internal memory are used to operate the function blocks of the next scan cycle. Researchers have recently developed an automated test generation technique aiming to satisfy several structural test coverage criteria for FBD programs. Among them, Jee et al.'s approach has an advantage of generating tests from FBD programs without requiring any intermediate models. However, test sequence generation for FBD programs with internal memory states was not fully automated in Jee et al.'s approach. This paper extends Jee et al.'s work by generating test sequences from FBD programs with internal memory states in a fully automated manner. The key technique involves explicitly unwinding FBD programs and solving the test requirements using an SMT solver. We conduct experiments on increasing the coverage of test requirements by unwinding cycles and evaluating the effectiveness of the test set using mutation analysis with several subject programs, including a real-world reactor protection system. The experimental results show that the proposed approach is able to generate effective test sequences for FBD programs. To demonstrate the efficiency of the proposed approach, we compared the test sequence generation time required for our approach with those for other approaches. The comparison results show that even excluding the generation time of test models of other approaches, the proposed approach increased the time-efficiency by more than 11 times.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Developing algorithms to generate test sets for Function Block Diagram programs. </LI> <LI> Defining Function Block Conditions for all the standard function blocks. </LI> <LI> Implementing an automated test sequence generation tool using Yices SMT solver. </LI> <LI> Demonstrating improved fault-detection effectiveness and time efficiency. </LI> </UL> </P>

High-throughput platform for 3D in vitro tumor vasculature model for real-time monitoring of Immune Cell Cytotoxicity

Jiyoung Song,Hyeri Choi,Seung Kwon Koh,Dohyun Park,Youngtaek Kim,Duck Cho,Noo Li Jeon 한국당과학회 2022 한국당과학회 학술대회 Vol.2022 No.07

Several advances in anticancer therapy have demonstrated significant improvements in clinical outcomes, and adoptive cell therapy has emerged as a type of immunotherapy that can modulate immune responses by transferring engineered immune cells. However, it remains a challenge because only a small percentage of respondents have responded. Three-dimensional (3D) in vitro models of the tumor microenvironment (TME) have the potential to provide a platform for assessing and predicting responses to therapy. Here, we propose an in vitro 3D tumor model with clusters of colorectal cancer (CRC) cells around perfusable vascular networks to evaluate immune cell-mediated cytotoxicity against cancer cells. A 3D injection-molded co-culture model consists of 28 microwells where identical vascularized cancer models can be formed in separate wells. It allows robust hydrogel patterning, resulting in high-throughput experiments. Compared to the polydimethylsiloxane (PDMS)-based microfluidic devices, our devices allowed a greater number of experiments to be conducted. A permeability test was also conducted to confirm the characteristics of the tumor vasculature. Primary natural killer (NK) cells were introduced into a tumor vascularized network and monitored using live-cell imaging. The extravasation, migration, and cytotoxic activity of six types of CRC cell lines were examined. Based on the consensus molecular subtypes (CMS) of CRC with distinct immune responses, CMS1 cancer cells were most susceptible to NK cell cytotoxicity. This study indicates the potential of our vascularized tumor model in assessing the responses to adoptive cell therapy by understanding the various steps involved in the immune response.

Study of Peak Load Demand Estimation Methodology by Pearson Correlation Analysis with Macro-economic Indices and Power Generation Considering Power Supply Interruption

Song, Jiyoung,Lee, Jaegul,Kim, Taekyun,Yoon, Yongbeum The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.8 No.1

Since the late 2000s, there has been growing preparation in South Korea for a sudden reunification of South and North Korea. Particularly in the power industry field, thorough preparations for the construction of a power infrastructure after reunification are necessary. The first step is to estimate the peak load demand. In this paper, we suggest a new peak demand estimation methodology by integrating existing correlation analysis methods between economic indicators and power generation quantities with a power supply interruption model in consideration of power consumption patterns. Through this, the potential peak demand and actual peak demand of the Nation, which experiences power supply interruption can be estimated. For case studies on North Korea after reunification, the potential peak demand in 2015 was estimated at 5,189 MW, while the actual peak demand within the same year was recorded as 2,461 MW. The estimated potential peak demand can be utilized as an important factor when planning the construction of power system facilities in preparation for reunification.

<i>N</i>-Heterocyclic Carbene-Based Conducting Polymer–Gold Nanoparticle Hybrids and Their Catalytic Application

Song, Sun Gu,Satheeshkumar, Chinnadurai,Park, Jiyoung,Ahn, Jongho,Premkumar, Thathan,Lee, Yunmi,Song, Changsik American Chemical Society 2014 Macromolecules Vol.47 No.19

<P>Hybrid nanocomposites of N-heterocyclic carbene (NHC)-functionalized conducting polymers (CPs) with gold nanoparticles (AuNPs) were prepared by concurrent disproportionation and oxidative coupling. The formation of hybrid nanocomposites, NHC-CP/AuNPs, in the simultaneous process was confirmed by transmission electron microscopy, powder X-ray diffraction, cyclic voltammetry, and C-13 solid-state NMR analyses. More importantly, the NHC group played a pivotal role in the dispersion of AuNPs. Further, NHC-CP/AuNPs exhibited good catalytic activity for the reduction of 4-nitrophenol.</P>

사회경제지표 기반 대도시 유동인구 예측

송지영(Jiyoung Song),곽호찬(Ho-Chan Kwak) 한국도시철도학회 2020 한국도시철도학회논문집 Vol.8 No.2

유동인구는 실제 사람들의 이동을 파악할 수 있는 자료로, 도시철도 건설 및 운영 계획 수립에 중요한 기초자료로 활용될 수 있다. 하지만 현재 유동인구 자료는 사후 구득만이 가능해 장래 개발계획 등에는 활용도가 낮은 실정이다. 이에 본 연구에서는 도시 및 인구 특성을 나타내는 사회경제지표를 활용하여 이동통신 자료 기반의 유동인구를 예측하기 위한 모형을 구축하였다. 모형 구축을 위해 2013년 12월 서울시 6개 구를 대상으로 수집된 유동인구 자료를 활용하여 회귀모형을 구축하였으며, 모형 구축 결과 사회경제지표 중 세대수와 종사자수 변수가 유동인구 예측에 통계적으로 유의성이 높은 것으로 나타났다. 또한 최종 모형의 적합도 분석 결과, R2이 0.97로 나타나해당 모형은 유동인구 예측에 활용도가 높을 것으로 사료된다. The floating population that is index to figure out urban mobility will be important in urban railway planning and operation. This study aims to estimate the model to predict floating population based on mobile phone data using socio-economic index. The floating population data that was collected at 6 districts in Seoul in December 2013 is used as dependent variable, and the linear regression analysis is used in modelling. The final model using the number of households and the number of employees showed good performance in urban floating population prediction as R2=0.97.