Nanostructured surfaces as biomimetic platforms to investigate cellular functions

Junsang DOH 한국생물공학회 2016 한국생물공학회 학술대회 Vol.2016 No.4

¹H-NMR-Based Metabolic Profiling of Cordyceps militaris to Correlate the Development Process and Anti-Cancer Effect

( Junsang Oh ),( Eunhyun Choi ),( Deok-hyo Yoon ),( Tae-yong Park ),( Bhushan Shrestha ),( Hyung-kyoon Choi ),( Gi-ho Sung ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.8

The study of metabolomics in natural products using the diverse analytical instruments including GC-MS, LC-MS, and NMR is useful for the exploration of physiological and biological effects and the investigation of drug discovery and health functional foods. Cordyceps militaris has been very attractive to natural medicine as a traditional Chinese medicine, due to its various bioactive properties including anti-cancer and anti-oxidant effects. In this study, we analyzed the metabolite profile in 50% ethanol extracts of C. militaris fruit bodies from three development periods (growth period, matured period, and aging period) using ¹H-NMR, and identified 44 metabolites, which are classified as 16 amino acids, 10 organic acids, 5 carbohydrates, 3 nucleotide derivatives, and 10 other compounds. Among the three development periods of the C. militaris fruit body, the aging period showed significantly higher levels of metabolites including cordycepin, mannitol (cordycepic acid), and β-glucan. Interestingly, these bioactive metabolites are positively correlated with antitumor growth effect; the extract of the aging period showed significant inhibition of HepG2 hepatic cancer cell proliferation. These results showed that the aging period during the development of C. militaris fruit bodies was more highly enriched with bioactive metabolites that are associated with cancer cell growth inhibition.

Effect of Post-Weld Heat Treatment Conditions on Mechanical Properties, Microstructures and Nonductile Fracture Behavior of SA508 Gr.1a Thick Weldments

Junsang Lee,Jong Sung Kim,Bongsang Lee,Sungwoo Cho,Dongil Kwon,Jong‑hyoung Kim 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

This study analyzes the effects of post-weld heat treatment (PWHT) on the mechanical properties and microstructures ofSA-508 Gr.1a welds and proposes a new PWHT exemption criterion based on nonductile fracture evaluation consideringwelding residual stress. The welding coupons were prepared with submerged-arc welding, gas-tungsten arc welding, andshielded-metal arc welding, using ferritic steel, SA-508 Gr.1a. The microstructure of the heat-affected zone (HAZ) was analyzedusing optical microscopy, electron-back-scatter diffraction and Vickers hardness testing. The mechanical propertiesof the welds were evaluated by uniaxial tensile test, transverse side bend test, Charpy V-notch impact test and side bend test. Bainite and ferrite structures formed mainly in the HAZ, and the grain size became coarser with proximity to the surfaceand fusion line. The mechanical properties did not depend strongly on PWHT, weldment thickness or welding techniques,and they satisfied the welding procedure qualification test specified in the ASME Boiler & Pressure Vessel code. Weldingresidual stresses were considered in assessing structural integrity using nonductile fracture evaluation. A margin of safetyagainst nonductile fracture with residual stress was calculated for Korean Standard Nuclear Power Plant steam-generatorwelds, using its design parameters and operating conditions, and this safety margin is suggested as an acceptance criterionfor residual stress for exemption from PWHT.

Translocation of charged particles through a thin micropore under pressure-driven flow

Junsang Moon,Chang Woo Song,Chang-Soo Han 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

We report the effects of a particle surface charge during translocation through a thin micropore based on the simulation and experiments. The translocation of carboxylated and nonfunctionalized polystyrene beads through a fabricated micropore was measured. To compare the translocation behaviors of a particle with/without surface charge under the same driving force, we used a pressure-driven method low bias voltage. We then analyzed the signals with two factors: the translocation time and blocking current. Based on the analysis, we found that, at a low flow rate, the translocation time was largely dependent on the surface charge of the particles. More importantly, we found an unusual phenomenon that the flow rate can affect the blocking current, and the level of effect was significantly determined by the particle’s surface charge. To understand this phenomenon, we suggest a plausible mechanism considering the effect of the convective flow on the counterion flux and FEM results.

A Survey of Decentralized Finance(DeFi) based on Blockchain

Junsang Kim(김준상),Seyong Kim(김세용) 한국컴퓨터정보학회 2021 韓國컴퓨터情報學會論文誌 Vol.26 No.3

블록체인 기술은 2008년 나카모토 사토시라는 신원미상의 인물이 비트코인이라는 암호화폐를 제안하면서 시작되었다. 나카모토 사토시는 기존의 금융 시스템에 대한 불신을 가지고 있었고 은행과 같은 중개자 없이도 해킹이나 변조에 견고한 금융시스템을 블록체인 기술을 통해 구현하고자 했다. 사토시는 비트코인의 생성과, 거래의 위조를 방지하기 위한 기술로 블록체인을 제안하였고 이를 통해 화폐의 발행과 거래, 그리고 검증의 기능을 구현하였다. 이후 스마트 계약을 블록체인 상에서 구현할 수 있는 암호화폐인 이더리움이 개발되면서 예금, 대출, 보험, 파생상품 등 복잡한 계약이 필요한 금융상품을 암호화폐의 영역으로 끌어들일 수 있게 되었다. 또한 실물자산과 결합을 통해 금융 기관이 제공했던 상품을 대체할 수 있는 가능성도 확대해 나가고 있다. 이러한 애플리케이션들을 Decentralized Finance(DeFi)라고 정의한다. 본 논문은 전반적인 DeFi의 기술적 이해와 현재 운영되고 있는 어플리케이션의 소개를 위하여 작성되었다. 먼저 전반적인 DeFi를 구현하는 기술들과 생태계에 대해서 설명한 후 대표적인 DeFi 애플리케이션들을 특징별로 분류하여 설명한다. Blockchain technology began in 2008 when an unidentified person named Satoshi Nakamoto proposed a cryptocurrency called Bitcoin. Satoshi Nakamoto had distrust of the existing financial system and wanted to implement a financial system that is robust against hacking or mannipulation without a middleman such as a bank through blockchain technology. Satoshi proposed a blockchain as a technology to prevent the creation of the bitcoin and forging of transactions, and through this, the functions of issuance, transaction, and verification of currency were implemented. Since then, Ethereum, a cryptocurrency that can implement the smart contract on the blockchain, has been developed, allowing financial products that require complex contracts such as deposits, loans, insurance, and derivatives to be brought into the area of cryptocurrency. In addition, it is expanding the possibility of substituting products provided by financial institutions through combination with real assets. These applications are defined as Decentralized Finance (DeFi). This paper was prepared to understand the overall technical understanding of DeFi and to introduce the services currently in operation. First, the technologies and ecosystems that implement the overall DeFi are explained, and then the representative DeFi services are categorized by feature and described.

Micro/Nanotechnology for Cancer Immunotherapy

Junsang Doh(도준상) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

Cancer immunotherapy has recently been successful in the treatment of various types of tumors. Cytotoxic lymphocytes, including cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, play an essential role in elimination of tumors by directly killing tumor cells. Therefore, evaluation of lymphocyte cytotoxicity against tumor cells is critical for the improvement of cancer immunotherapy. Lymphocyte cytotoxicity is a strictly regulated function requiring a multi-step “checkpoint” to minimize normal cell damage. However, current cytotoxicity assays mostly provide information about final outcomes of cytotoxicity. To overcome this limitation, we are developing new assays that allow “stepwise” evaluation of lymphocyte cytotoxicity using dynamic imaging and microfabrication techniques.

Effect of Association on Valuating Sport Athlete Items:Moderating role of involvement

Junsang Ahn 서울대학교 스포츠과학연구소 2012 스포츠과학리뷰 Vol.6 No.1

유명 인사들의 물건들은 물건 자체가 갖는 시장가격보다 훨씬 높은 가격에 판매가 되는 것을 자주 목격할 수 있다. 이는 곧 사람들이 이러한 물건들의 가치를 평가함에 있어 단순히 시장가격을 바탕으 로 하기보다는 유명 인사들이 소유하고 있었다는 그 자체에 높은 가격을 책정한다고 할 수 있다. 스 포츠 운동선수들의 경우 스포츠에 대한 사회 전반적인 관심이 높아지면서 우수한 운동선수들의 경우 웬만한 유명인사들 보다 더 많은 인기를 구사하고 더 많은 팬들을 보유하고 있다. 따라서 본 연구는 운동선수들과 팬들의 연상 정도가 선수들의 물건에 대한 평가에 어떠한 영향을 미치는지 알아보고자 한다. 물건에 대한 평가에 그 물건 자체에 대한 팬들의 관여도가 어떠한 조절효과를 보이는지도 확인 하고자 한다.

Designer’s Unpack

Junsang Park(박준상) 한국디자인학회 2023 한국디자인학회 국제초대전도록 Vol.2023 No.6

Effect of particle surface charges during translocation through a micropore in pressure-driven flow

Junsang Moon(문준상),Chang-Soo Han(한창수) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.8

The Showcase

Junsang Park(박준상) 한국디자인학회 2023 한국디자인학회 국제초대전도록 Vol.2023 No.6