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Brain-on-a-chip for disease modelling
SEUNGWOO CHO 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Modeling brain development and neuronal disorders remains a great challenge due to the complexity of the structures, physiology, and functions of human brain. Several in vitro models have been established for brain disease modelling and drug discovery. However, they are often limited in recapitulating complex cellular/extracellular interactions and physiological aspects. To overcome limitations of current models, we have developed a brain-on-a-chip technology with organoids and microfluidics. Human brain organoids generated with brain extracellular matrix and microfluidic device could successfully reconstitute structural and physiological features of neuroepithelium development and corticogenesis. We have also established neurovascular unit chip with functional blood-brain-barrier for infectious brain disease modelling. Our strategy using brain-on-a-chip with brain organoids and neurovascular units would be able to facilitate elucidation of brain disease mechanism and development of novel therapeutics.
Flexible Thermoelectric Device Using Thick Films for Energy Harvesting from the Human Body
Cho, Han Ki,Kim, Da Hye,Sin, Hye Sun,Cho, Churl-Hee,Han, Seungwoo The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.6
A flexible thermoelectric device using body heat has drawn attention as a power source for wearable devices. In this study, thermoelectric thick films were fabricated by cold pressing method using p-type antimony telluride and n-type bismuth telluride powders in accordance with specific loads. Thermoelectric thick films were denser and improved the electrical and thermoelectric properties while increasing the load of the cold pressing. The thickness of the specimen can be controlled by the amount of material; specimens were approximately 700 um in thickness. Flexible thermoelectric devices were manufactured by using the thermoelectric thick films on PI (Polyimide) substrate. The process is cheap, efficient, easy and scalable. Evaluation of power generation performance and flexibility on the fabricated flexible thermoelectric device was carried out. The flexible thermoelectric device has great flexibility and good performance and can be applied to wearable electronics as a power source.
Kim, Seungwoo,Shin, Youngmi,Shin, Youngju,Park, Yang-Seo,Cho, Nam Jeong Korean Society for Molecular Biology 2008 Molecules and cells Vol.25 No.4
Three G-protein-linked acetylcholine receptors (GARs) exist in the nematode C. elegans. GAR-3 is pharmacologically most similar to mammalian muscarinic acetylcholine receptors (mAChRs). We observed that carbachol stimulated ERK1/2 activation in Chinese hamster ovary (CHO) cells stably expressing GAR-3b, the predominant alternatively spliced isoform of GAR-3. This effect was substantially reduced by the phospholipase C (PLC) inhibitor U73122 and the protein kinase C (PKC) inhibitor GF109203X, implying that PLC and PKC are involved in this process. On the other hand, GAR-3b-mediated ERK1/2 activation was inhibited by treatment with forskolin, an adenylate cyclase (AC) activator. This inhibitory effect was blocked by H89, an inhibitor of cAMP-dependent protein kinase A (PKA). These results suggest that GAR-3b-mediated ERK1/2 activation is negatively regulated by cAMP through PKA. Together our data show that GAR-3b mediates ERK1/2 activation in CHO cells and that GAR-3b can couple to both stimulatory and inhibitory pathways to modulate ERK1/2.
Hong, Seungwoo,Lee, Yong-Min,Cho, Kyung-Bin,Sundaravel, Karuppasamy,Cho, Jaeheung,Kim, Myoung Jin,Shin, Woonsup,Nam, Wonwoo American Chemical Society 2011 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.133 No.31
<P>Mononuclear nonheme iron(IV)-oxo complexes with two different topologies, <I>cis</I>-α-[Fe<SUP>IV</SUP>(O)(BQCN)]<SUP>2+</SUP> and <I>cis</I>-β-[Fe<SUP>IV</SUP>(O)(BQCN)]<SUP>2+</SUP>, were synthesized and characterized with various spectroscopic methods. The effect of ligand topology on the reactivities of nonheme iron(IV)-oxo complexes was investigated in C–H bond activation and oxygen atom-transfer reactions; <I>cis</I>-α-[Fe<SUP>IV</SUP>(O)(BQCN)]<SUP>2+</SUP> was more reactive than <I>cis</I>-β-[Fe<SUP>IV</SUP>(O)(BQCN)]<SUP>2+</SUP> in the oxidation reactions. The reactivity difference between the <I>cis</I>-α and <I>cis</I>-β isomers of [Fe<SUP>IV</SUP>(O)(BQCN)]<SUP>2+</SUP> was rationalized with the Fe<SUP>IV/III</SUP> redox potentials of the iron(IV)-oxo complexes: the Fe<SUP>IV/III</SUP> redox potential of the <I>cis</I>-α isomer was 0.11 V higher than that of the <I>cis</I>-β isomer.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2011/jacsat.2011.133.issue-31/ja204008u/production/images/medium/ja-2011-04008u_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja204008u'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja204008u'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja204008u'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja204008u'>ACS Electronic Supporting Info</A></P>
The Effect of Injector Nozzle Number on Spray and Combustion in a Light-Duty Diesel Engine
( Seungwoo Kang ),( Wonkyu Cho ),( Choongsik Bae ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
This paper investigated the number effect of diesel injector nozzle on spray and combustion in a light-duty diesel engine with 250MPa injection. The liquid and vapor spray visualization was conducted in constant-volume combustion chamber. The engine used for the experiment was the 0.4L single-cylinder diesel engine. Three injectors that were compared had identical hydraulic flow rate, and their nozzle numbers were 8 to 10. The orifice diameter decreased from 105 ㎛ to 95 ㎛ as the nozzle number increased. The vapor and liquid spray penetration decreased with larger nozzle number and smaller orifice diameter. However, the total cross-sectional areas of vapor spray from 8 to 10-hole injectors were similar. In the engine, injector with larger nozzle number and smaller orifice diameter showed the shorter ignition delay. The particulate matter(PM) emission was lower with larger nozzle number and smaller orifice diameter. Improved the atomization of the fuel spray from smaller nozzle diameter while the fuel spray area was kept results shorter ignition delay and lower PM emission. However, at higher injection pressure, the NOx-PM trade-offs from three injectors were similar. The effect of injection pressure was dominant for reducing PM emission, and then the effect of nozzle geometry was indistinguishable. The indicated specific fuel consumption was similar because their injection rate and in-cylinder pressure trace was similar. Also, the 8-and 10-hole injectors with same orifice diameter(95 ㎛) was also compared for identify the nozzle effect with constant orifice diameter. The 10-hole injector showed improved PM-NOx emission trade-off and fuel consumption because the increased nozzle number widened the fuel distribution in the cylinder. This research will provide guideline for optimization of the injector nozzle configuration.
Cho Hee-Mun,Kim Hyunji,Jang Jihee,Cha Seungwoo,Chang Won Kee,Jung Bong-Keun,Park Dae-Sung,Jee Sungju,Ko Sung-Hwa,Shin Joon-Ho,Kim Won-Seok,Paik Nam-Jong 대한뇌신경재활학회 2023 뇌신경재활 Vol.16 No.1
The attitude toward telerehabilitation (TR) among therapists (191 physical therapists and 159 occupational therapists) in Korea was sur veyed. The sur vey consisted of 15 questions in the following 8 domains: awareness(AW), attitude (AT), perceived usefulness (PU), perceived behavioral control (PBC), self-efficacy (SE), facilitating conditions (FC), barriers (B), and behavioral intention (BI). Therapists with experience in TR responded with higher scores in all domains except B, regardless of their specialty. The most perceived barriers to TR were unmatched insurance fees and a lack of technical support. Experience with TR was a major factor in attitude and behavior intention toward TR