An efficient isolation of foodborne pathogen using surface-modified porous sponge

Choi, Yunho,Kim, Yong Tae,You, Jae Bem,Jo, Sung Hee,Lee, Seok Jae,Im, Sung Gap,Lee, Kyoung G. Elsevier 2019 Food chemistry Vol.270 No.-

<P><B>Abstract</B></P> <P>Rapid and efficient detection of pathogenic bacteria from food is critical to prevent epidemic food poisoning. However, the isolation of pathogenic bacteria from spoiled food is hampered by the lack of proper cell cultivation and/or isolation methods. Most of currently used methods suffer from complex, time-consuming culturing steps, low scalability, and high operation cost. Herein, we developed an alternative approach for the isolation of pathogenic bacteria directly from food using a surface-modified, highly porous sponge via initiated chemical vapor deposition (iCVD) process. A hydrophobic polymer, poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetra-siloxane) (pV4D4), was deposited conformally on amphiphilic 3-dimensional (3D) melamine sponge to incorporate hydrophobicity as well as oleophilicity to the porous sponge surface, which is appropriate for absorbing oil component selectively from food extracts. Furthermore, the surface-modified sponge was capable of the isolation of <I>Escherichia coli</I> O157:H7 (<I>E. coli</I> O157:H7) from heterogeneous mixture with oil/water/food particles with undistinguisible efficiency compare to artificial model system. The surface-modified sponge developed in this study will be a novel platform for oil/water separation and isolation of foodborne pathogens directly from heterogeneous mixture to enhance the efficiency of molecular diagnostics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Functional and porous sponge is fabricated for isolation of pathogenic cells. </LI> <LI> Fabricated sponge exhibits high selectivity for water and oil absorption. </LI> <LI> Pathogenic bacteria can be successfully recovered from real food mixture. </LI> <LI> Fabricated sponge can be used as a platform for diagnosis of foodborne illness. </LI> </UL> </P>

Polyketone & Polyamide 6I alloy research

Yunho Choi,S.H Joo,K.S Byun 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Multifunctional polymer micropattern for integrated digital loop-mediated isothermal amplification

Yunho Choi,Younseong Song,Yong Tae Kim,Seok Jae Lee,Kyoung G. Lee,Sung Gap Im 한국진공학회 2021 한국진공학회 학술발표회초록집 Vol.2021 No.2

The digital nucleic acid assay is a precise, sensitive, and accurate method for nucleic acid analysis based on digitized amplification and detection. Here, we propose a multifunctional polymer micropattern enabling nucleic acid partitioning and direct DNA extraction and digitized quantification thereof. The multifunctional polymer micropattern is fabricated by the deposition of a copolymer film, poly(2-dimethylaminomethyl styrene-co-hydroxyethyl methacrylate) (pDH), via photo-initiated chemical vapor deposition (piCVD) process, followed by hydrophobic microcontact printing (µCP) to obtain partitions for nucleic acid isolation. With intrinsic positive charge of pDH, it enables bacteria lysis and DNA capture, while showing exceptional water stability for more than 24 h. µCP-treated pDH surface is also stable under aqueous conditions at high temperature (70°C) for 1 h. Using multifunctional polymer micropattern, loop-mediated isothermal amplification (LAMP) in each partition can detect DNA templates over a concentration range of 0.01 ― 2 ng/µL. The untreated bacteria cells can also be detected by direct compartmentalization, followed by on-site cell lysis and digital LAMP. For Escherichia coli 0157:H7, Salmonella enteritidis, and Staphylococcus aureus cells, cell numbers ranging from 1.4 x 10⁴ to 1.4 x 10⁷ can be quantitatively detected using the multifunctional polymer micropattern. The suggested multifunctional polymer micropattern provides a novel multifunctional compartmentalization method for rapid, simple, and accurate digital LAMP.

The Effect of Intervention for Improving Colonoscopy Quality Is Associated with the Personality Traits of Endoscopists

Choi Hyun Ho,Sung Soo-Yoon,Lee Bo-In,Cho Hyun,Jung Yunho,Park Jae Myung,Cho Young-Seok,Lee Kang Moon,Kim Sang Woo,Choi Hwang,Chae Hiun-Suk,Choi Myung-Gyu 거트앤리버 소화기연관학회협의회 2024 Gut and Liver Vol.18 No.2

Background/Aims: This study investigated whether the personality traits of endoscopists are associated with the effect of interventions for the improvement of colonoscopy quality. Methods: This prospective, multicenter, single-blind study was performed with 13 endoscopists in three health screening centers over a 12-month period. Quality indicators (QIs), including adenoma detection rate (ADR), polyp detection rate (PDR), and withdrawal time, were measured every 3 months. Consecutive interventions for the improvement of colonoscopy quality were conducted every 3 months, which included the personal notification of QIs, the in-group notification of QIs, and finally a targeted “quality education” session. The personality traits of each endoscopist were evaluated for perfectionism, fear of negative evaluation, and cognitive flexibility after the last QI assessment. Results: A total of 4,095 colonoscopies were evaluated to measure the QIs of the individual endoscopists for 12 months. The mean ADR, PDR, and withdrawal time of the 13 endoscopists were 32.3%, 47.7%, and 394 seconds at baseline and increased to 39.0%, 55.1%, and 430 seconds by the end of the study (p=0.003, p=0.006, and p=0.004, respectively). Among the three interventions, only quality education significantly improved QIs: ADR, 36.0% to 39.0% (odds ratio, 1.28; 95% confidence interval, 1.01 to 1.63). The improvement of ADR and PDR by education was significantly associated with perfectionism (r=0.617, p=0.033 and r=0.635, p=0.027, respectively) and fear of negative evaluation (r=0.704, p=0.011 and r=0.761, p=0.004, respectively). Conclusions: Education can improve colonoscopy quality, and its effect size is associated with an endoscopist’s personal traits such as perfectionism and fear of negative evaluation (Clinical- Trials.gov Registry NCT03796169).

Viewpoint Estimation for Visual Target Navigation by Leveraging Keypoint Detection

Yunho Choi,Nuri Kim,Jeongho Park,Songhwai Oh 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

In this paper, we tackle the problem of visual target navigation which is a crucial task for embodied AI. Given a target observation and an initial observation, we extract keypoints using an off-the-shelf keypoint detection model. Then we find sparse keypoint correspondences and estimate the relative camera pose with the PnP algorithm to reach the viewpoint for the target observation. Compared to conventional approaches, our method is faster, and more robust to scene changes and occlusions. We collected a 3D scan dataset in a university building and the proposed method is verified using the dataset.

음향공의 형상 및 개수에 따른 Rijke Tube 내부 열환경에서의 감쇠 성능 평가

최윤호(YunHo Choi),김홍집(HongJip Kim) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.5

음향공은 로켓 연소실 같이 폐쇄된 연소실에서 빈번하게 일어나는 연소 불안정을 제어하는 안정화 장치로서 널리 사용되어져 왔다. 이러한 음향공의 불안정 감쇠 능력은 음향공 주변 환경에 따라서 달라지는데, 열환경에서의 감쇠 능력을 평가하기 위해 Rijke Tube를 이용해서 실험을 수행하였다. 오리피스 직경과 길이가 증가할수록 더 좋은 감쇠 능력을 보여주었다. 음향공 개수의 효과로 인해 감쇠 능력은 개수의 증가에 따라 증가하는데, 일정 개수 이상에서는 감쇠 능력이 크게 증가하지 않는 것으로 확인되었다. 결론적으로 열환경에서의 실험 결과 역시 음향공의 형상과 개수를 최적화하는 것이 필요하다는 것을 입증하였다. Acoustic cavity has been widely used as a stabilization device to control the combustion instability frequently occurring in a closed chamber as a rocket combustion chamber. Damping characteristics of the acoustic cavities have been measured by a Rijke tube for the evaluation of a damping capacity in thermal environment. Acoustic cavities having large orifice area or long orifice length showed better damping capacity. As for the number effect of cavities, damping capacity increases with the number, but, in certain number or more, the significant increase of the damping capacity was not found. Finally, it was proved that thermal environment experiment is also necessary to optimize the shape and number of the cavity.

시각적 메모리 기반 로봇 네비게이션 연구동향 분석

최윤호(Yunho Choi),김누리(Nuri Kim),오성회(Songhwai Oh) 대한전기학회 2019 정보 및 제어 심포지엄 논문집 Vol.2019 No.10

심신상실자에 의한 피해자에 대한 감독자의 책임

최윤호(Yunho Choi) 성균관대학교 법학연구원 2023 성균관법학 Vol.35 No.2

BLDC 모터 내부의 홀센서를 이용한 전기식 구동장치의 구현

최윤호(YunHo Choi),박은주(EunJoo Park),서석훈(SuhkHun Suh) 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12

최근 유도무기에 적용되는 전기식 구동장치 개발에 있어 무게 저감, 소형화 및 저가화를 위한 다양한 방안이 검토되고 있다. 본 논문에서는 구동장치의 소형화를 위한 방안으로 구동축의 구동각을 계측하기 위한 분압기를 사용하지 않고 BLDC 모터의 회전을 위해 사용되는 모터 내부의 홀센서만으로 구동각을 제어하는 구동장치를 구현하고 분압기를 사용하는 일반적 구동장치와 성능시험 결과를 비교하여 적용 가능성을 검토하였다. Recently, various methods for weight reduction, miniaturization and cost reduction have been considered in the development of electro-mechanical actuator applied to guided weapons. In this paper, we implemented a actuator that measures the driving angle only by the Hall sensor used for the rotation of the BLDC motor without using the potentiometer to measure the driving angle of the driving shaft for miniaturization of the driving device. In addition, the performance test results were compared with the general actuator using a potentiometer to applicability.

핀틀의 위치제어를 위한 전기식 구동장치 제어기의 FPGA 설계

최윤호(Yunho Choi),박양규(Yangkyu Park),박은주(Eunjoo Park),백기봉(Kibong Baek) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11

FPGA(field programmable gate array)는 재프로그래밍이 가능한 디지털 반도체 소자로써 로직 블록 및 프로그래밍 가능한 연결선을 가지고 있어 원하는 하드웨어 기능을 수행하는 반도체를 설계할 수 있다. 본 논문에서는 FPGA의 하드웨어적 유연성을 바탕으로 구동제어기의 주요 기능을 FPGA를 구현하여 고정된 Latency를 갖는 안정적 구동장치 제어기를 설계하였다. 또한 FPGA의 로직을 RTL(Register Transfer Level) 시뮬레이션을 통하여 검증하였으며 최종적으로 구동장치 연동시험을 통해 구현된 제어기의 안정적 동작을 확인하였다. The FPGA is a reprogrammableArray of logic gate that has a logic block and reconfigurable interconnects , allowing to design a semiconductor that performs the desired digital hardware function. In this paper, based on the hardware flecibility of th FPGA, the main function of the actuator controller is implemented in an FPGA to design a stable actuator controller with a fixed latency. In addition, the logic design resultof the FPGA was verified through RTL simulation, and finally, the stable opertation of the implemented controller was confirmed through the actuator integration test.