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Hair Separation and Detection in Mutant Drosophila Hair Images
Jihoon Kwak,Chun-Taek Oh,Sung-Jun Han,Myungjoo Kang 한국산업응용수학회 2010 한국산업응용수학회 학술대회 논문집 Vol.5 No.1
To test the genotoxicity of drug candidates in the process of drug discovery, The Drosophila wing somatic mutation and recombination test (SMART)[3][1] is used, which analyzes the development frequency of mutant hairs of Drosophila. Because the current mutant hair counting method is totally manual work, in which humans search and count the mutant hairs by their eyes through the microscope, its speed and accuracy is limited. Our goal is to culture the mutant Drosophila using possibly genotoxic chemicals, to take the image of Drosophila wing hair, and to develop an automated system that counts mutant hairs and tells the genotoxicity of the chemicals. In this work, we explain the image acquisition method using multi-focused image stack, hair separation method into upper and lower hair, and hair detection method using template matching.
3D Detection of Mutant Hairs in Drosophila Wing Images
Jihoon Kwak,Chun-Taek Oh,Sung-Jun Han,Michael Adsetts Edberg Hansen,Auguste Genovesio,Myungjoo Kang 한국산업응용수학회 2011 한국산업응용수학회 학술대회 논문집 Vol.6 No.1
We developed an automated mutant hair counting system in Drosophila wing images. In our previous work [2], we developed the image acquisition method using multi-focused image stack, hair separation method into upper and lower hair, and hair detection method using template matching. In this work, the hair detection and mutant classification algorithms are enhanced and extended to 3D, and the wing area segmentation is newly developed.
Zinc finger proteins orchestrate active gene silencing during embryonic stem cell differentiation
Kwak, Sojung,Kim, Tae Wan,Kang, Byung-Hee,Kim, Jae-Hwan,Lee, Jang-Seok,Lee, Han-Teo,Hwang, In-Young,Shin, Jihoon,Lee, Jong-Hyuk,Cho, Eun-Jung,Youn, Hong-Duk Oxford University Press 2018 Nucleic acids research Vol.46 No.13
<P><B>Abstract</B></P><P>Transcription factors and chromatin remodeling proteins control the transcriptional variability for ESC lineage commitment. During ESC differentiation, chromatin modifiers are recruited to the regulatory regions by transcription factors, thereby activating the lineage-specific genes or silencing the transcription of active ESC genes. However, the underlying mechanisms that link transcription factors to exit from pluripotency are yet to be identified. In this study, we show that the Ctbp2-interacting zinc finger proteins, Zfp217 and Zfp516, function as linkers for the chromatin regulators during ESC differentiation. CRISPR-Cas9-mediated knock-outs of both Zfp217 and Zfp516 in ESCs prevent the exit from pluripotency. Both zinc finger proteins regulate the Ctbp2-mediated recruitment of the NuRD complex and polycomb repressive complex 2 (PRC2) to active ESC genes, subsequently switching the H3K27ac to H3K27me3 during ESC differentiation for active gene silencing. We therefore suggest that some zinc finger proteins orchestrate to control the concise epigenetic states on active ESC genes during differentiation, resulting in natural lineage commitment.</P>
도플러 레이더 패턴 인식을 통한 인간 보행 감지 및 배경잡음 제거 기법
권지훈(Jihoon Kwon),곽노준(Nojun Kwak) 한국자동차공학회 2016 한국자동차공학회 부문종합 학술대회 Vol.2016 No.5
In the conventional radar system, a threshold level is adjusted by the received noise level for maintaining detection and false alarm performances. However, when high level noise is received, a threshold level also increases and detection range can be reduced. In this paper, we will present a new method of pedestrian detection and background noise classification using Doppler radar pattern recognition technique without using a threshold level. We apply the multilayer perceptron to classify the human normal walking motion from the background noise. The estimation accuracy for the background noise and human normal walking motion are about 97.9% and 90.1% individually. This result shows that the pattern recognition approach can be the effective method to remove the background noise for pedestrian detection.
Efficient and selective removal of heavy metals using microporous layered silicate AMH-3 as sorbent
Kim, Jihoon,Kwak, Seung-Yeop Elsevier 2017 Chemical Engineering Journal Vol.313 No.-
<P><B>Abstract</B></P> <P>AMH-3 is a zeolite-like material with a three-dimensional uniform porous structure, layered structure, and abundant exchangeable cations. Herein, the use of AMH-3 to remove heavy metals present in aqueous solutions is investigated for the first time. Pristine AMH-3 and metal-sorbed AMH-3 were characterized with inductively coupled plasma atomic emission spectroscopy (ICP-AES), field emission scanning electron microscopy (FE-SEM), <SUP>29</SUP>Si cross polarization magic angle spinning nuclear magnetic resonance spectroscopy (CP MAS NMR) and X-ray diffraction (XRD). The removal of heavy metals by AMH-3 was found to be governed by ion exchange rather than surface adsorption, and no significant change occurred in the structure of the AMH-3 during the ion exchange. The removal of various heavy metal ions (Pb<SUP>2+</SUP>, Cu<SUP>2+</SUP>, Cd<SUP>2+</SUP>, and Zn<SUP>2+</SUP>) onto AMH-3 from aqueous solutions was conducted using a batch method. The effects of influential parameters, such as the initial metal ion concentration and contact time, on the sorption process were studied. The metal ion sorption capacity and removal efficiency were mainly dependent on the difference between the effective pore size of the AMH-3 and the hydrated radius of the metal ion. The sorption isotherm data were well fitted by Langmuir (for Pb<SUP>2+</SUP>, Cu<SUP>2+</SUP>, and Zn<SUP>2+</SUP>) and Freundlich (for Cd<SUP>2+</SUP>) models. The sorption kinetics data were well fitted by a pseudo-secondorder kinetic model. Competitive sorption experiments revealed an order of metal ion affinity of Pb<SUP>2+</SUP> >Cu<SUP>2+</SUP> >Zn<SUP>2+</SUP> >Cd<SUP>2+</SUP>. These findings indicate that AMH-3 is suitable for the efficient and selective removal of heavy metals from aqueous solutions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AMH-3 has unique framework and abundant exchangeable cations. </LI> <LI> The removal of metal ions was governed by ion exchange rather than surface adsorption. </LI> <LI> AMH-3 exhibited a high sorption capacities for metal ions. </LI> <LI> Metal ions were selectively removed by AMH-3 pore size. </LI> </UL> </P>
Kim, Jihoon,Lee, Yongkyu,Jeon, Jae-Deok,Kwak, Seung-Yeop Elsevier 2018 Journal of Power Sources Vol.383 No.-
<P><B>Abstract</B></P> <P>A series of ion-exchange membranes for vanadium redox flow batteries (VRBs) are prepared by filling the pores of a poly(tetrafluoroethylene) (PTFE) substrate with sulfonated poly(ether ether ketone) (SPEEK) and microporous Engelhard titanosilicate-10 (ETS-10). The effects of ETS-10 incorporation and PTFE reinforcement on membrane properties and VRB single-cell performance are investigated using various characterization tools. The results show that these composite membranes exhibit improved mechanical properties and reduced vanadium-ion permeabilities owing to the interactions between ETS-10 and SPEEK, the suppressed swelling of PTFE, and the unique ETS-10 framework. The composite membrane with 3 wt% ETS-10 (referred to as “SE3/P”) exhibits the best membrane properties and highest ion selectivity. The VRB system with the SE3/P membrane exhibits higher cell capacity, higher cell efficiency, and lower capacity decay than that with a Nafion membrane. These results indicate that this composite membrane has potential as an alternative to Nafion in VRB systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pores of PTFE membrane were filled with SPEEK and ETS-10. </LI> <LI> The composite membranes showed enhanced membrane stability. </LI> <LI> ETS-10 acted as a permselective barrier to reduce vanadium permeability. </LI> <LI> The composite membranes exhibited better VRB cell performance than Nafion. </LI> </UL> </P>
떼를 지은 세라티아 마르체센스의 전기주성(電氣走性)을 이용한 마이크로 구조물의 제어에 관한 실험적 연구
곽영헌(Young-Hun Kwak),김달형(Dalhyung Kim),김지훈(Jihoon Kim),김지영(Jiyoung Kim),김기로(Kiro Kim),김민준(Min-Jun Kim),변도영(Doyoung Byun) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Serratia marcescens are rod-shaped bacterium, human pathogen, and flagellate bacteria. We have investigated micro-actuator based on SU-8 structures by S. marcescens in microfluidics system. Microstructures fabricated using conventional micro-fabrication techniques are blotted on the swarm plate, which leaves a bacterial monolayer on the surface of the microstructure. We have investigated microstructures powered by S. marcescens to determine how cell orientation on the microstructure surface relates to the swarming patterns as well as how the orientation is affected by external stimulus. From this result, we will help to enhanced direction control of bacteria such as micro-assembly and micro-manipulation.
A Study of Phosphorescent Light Emitting Using Cyclometalated Pt(II) Complexes.
Son, Seokhwan,Lee, Hwangyu,Kwak, Cheehun,Lee, Jihoon,Ahn, Hogeun,Chung, Minchul American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.7
<P>The reaction of platinum [Pt(4-(N,N-bis(piridyl)amino)stilbene)]Cl2 with 5,5'-(9,9-dioctyl-9H-fluorene- 2,7-diyl)di-2,2'-bipyridine, 2,2'-bipyridine, and 1,10-phenathroline affords the following complexes: [(4-(N,N-bis(piridyl)amino)stilbene)Pt(5,5'-(9,9-dioctyl-9H-fluorene-2,7-diyl)di-2,2'-bipyridine)] (1), [(4-(N,N-bis(piridyl)amino)stilbene)Pt(2,2'-bipyridine)] (2), and [(4-(N,N-bis(piridyl)amino)stilbene) Pt(1,10-phenathroline)] (3). In this study, new platinum complex compounds were synthesized utilizing the ligand of a 4-(N,N-bis(piridyl)amino)stilbene system. These complexes were analyzed using a 1H(13C)-NMR, UV-vis and PL spectrophotometer. The maximum wavelengths of complexes 1, 2, and 3 appear at 409 nm, 410 nm, and 503 nm, respectively. The quantum yields of these complexes are 0.32-0.92.</P>