Composition-Tunable Synthesis of Large-Scale Mo_1-<i>x</i>W_<i>x</i>S₂ Alloys with Enhanced Photoluminescence

Park, Juhong,Kim, Min Su,Park, Bumsu,Oh, Sang Ho,Roy, Shrawan,Kim, Jeongyong,Choi, Wonbong American Chemical Society 2018 ACS NANO Vol.12 No.6

<P>Alloying two-dimensional transition metal dichalcogenides (2D TMDs) is a promising avenue for band gap engineering. In addition, developing a scalable synthesis process is essential for the practical application of these alloys with tunable band gaps in optoelectronic devices. Here, we report the synthesis of optically uniform and scalable single-layer Mo<SUB>1-<I>x</I></SUB>W<SUB><I>x</I></SUB>S<SUB>2</SUB> alloys by a two-step chemical vapor deposition (CVD) method followed by a laser thinning process. The amount of W content (<I>x</I>) in the Mo<SUB>1-<I>x</I></SUB>W<SUB><I>x</I></SUB>S<SUB>2</SUB> alloy is systemically controlled by the co-sputtering technique. The post-laser process allows layer-by-layer thinning of the Mo<SUB>1-<I>x</I></SUB>W<SUB><I>x</I></SUB>S<SUB>2</SUB> alloys down to a single-layer; such a layer exhibits tunable properties with the optical band gap ranging from 1.871 to 1.971 eV with variation in the W content, <I>x</I> = 0 to 1. Moreover, the predominant exciton complexes, trions, are transitioned to neutral excitons with increasing W concentration; this is attributed to the decrease in excessive charge carriers with an increase in the W content of the alloy. Photoluminescence (PL) and Raman mapping analyses suggest that the laser-thinning of the Mo<SUB>1-<I>x</I></SUB>W<SUB><I>x</I></SUB>S<SUB>2</SUB> alloys is a self-limiting process caused by heat dissipation to the substrate, resulting in spatially uniform single-layer Mo<SUB>1-<I>x</I></SUB>W<SUB><I>x</I></SUB>S<SUB>2</SUB> alloy films. Our findings present a promising path for the fabrication of large-scale single-layer 2D TMD alloys and the design of versatile optoelectronic devices.</P> [FIG OMISSION]</BR>

Rapid Differential Diagnosis of Breast Microcalcification Using Targeted Near-Infrared Fluorophores

Park, Min Ho,Lim, Wonbong,Jo, Danbi,Jung, Jin Seok,Kim, Subin,Kim, Jangho,Lim, Hyo Soon,Lee, Ji Shin,Min, Jung-Joon,Hyun, Hoon Wiley - VCH Verlag GmbH & Co. KGaA 2018 Advanced Healthcare Materials Vol.7 No.7

Reforming Tool to Measure MEDICAL ETHICS CONSCIOUSNESS of Korean Young Students

Wonbong Lee,Gyunyeol Park J-INSTITUTE 2021 Public Value Vol.6 No.2

Purpose: This study complements some of the limitations of the past developed tool for measuring medical ethics consciousness of Korean young students. Method: This study was based on the past tool which was developed according to G. Lind of Germany. The validity process followed the verification procedure of Moral Competence Test (MCT) proposed by G. Lind. To get much higher validation, this study got advices from 3 specialist in the sphere of moral education. Results: This study adopted the result of the past medical ethics consciousness measurement tool. Its whole validation did cover three major processes, preference hierarchy by moral development, affective-cognitive par-allelism test, quasi-simplex structure of inter-correlations between the six moral orientations test by L. Kohlberg. This past tool showed weakness in the point of preference hierarchy test. Especially the tool got some strange situation at 1st stage and 4th stage. To back up this weakness, we made a decision to receive specialists’ advices. So we interviewed 3 people who is professor or research fellow in the sphere of moral education. We could arrived at more advanced level for medical ethics consciousness. Conclusion: This study showed the more advanced medical ethics consciousness tool. Next time it is necessary to generalized through deep research using much broader topics in the medical ethics.

Synthesis and characterization of new functional poly(urethane-imide) crosslinked networks

Park, Mi-Hee,Jang, Wonbong,Yang, Seung-Jin,Shul, Yonggun,Han, Haksoo Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of applied polymer science Vol.100 No.1

<P>To synthesize new functional poly(urethane-imide) crosslinked networks, soluble polyimide from 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 4,4′-oxydianiline, and maleic anhydride and polyurethane prepolymer from polycaprolactone diol, tolylene 2,4-diisocyanate and hydroxyl ethyl acrylate were prepared. Poly(urethane-imide) thin films were finally prepared by the reaction between maleimide end-capped soluble polyimide (PI) and acrylate end-capped polyurethane (PU). The effect of polyurethane content on dielectric constant, residual stress, morphology, thermal property, and mechanical property was studied by FTIR, prism coupler, Thin Film Stress Analyzer (TFSA), XRD, TGA, DMTA, and Nano-indentation. Dielectric constant of poly(urethane-imide) thin films (2.39–2.45) was lower than that of pure polyimide (2.46). Especially, poly(urethane-imide) thin films with 50% of PU showed lower dielectric constant than other poly(urethane-imide) thin films did. Lower residual stress and slope in cooling curve were achieved in higher PU content. Compared to typical polyurethane, poly(urethane-imide) thin films exhibited better thermal stability due to the presence of the imide groups. The glass transition temperature, modulus, and hardness decreased with increase in the flexible PU content even though elongation and thermal expansion coefficient increased. Finally, poly(urethane-imide) thin films with low residual stress and dielectric constant, which are strongly affected by the morphological structure, chain mobility, and modulus, can be suggested to apply for electronic devices by variation of PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 113–123, 2006</P>

The anti-inflammatory mechanism of 635 nm light-emitting-diode irradiation compared with existing COX inhibitors

Lim, Wonbong,Lee, SungGa,Kim, Inae,Chung, Mina,Kim, Misook,Lim, Hoisoon,Park, Jinsoo,Kim, Okjoon,Choi, Hongran Wiley Subscription Services, Inc., A Wiley Company 2007 Lasers in surgery and medicine Vol.39 No.7

<B>Background and Objectives</B><P>Inhibition of cyclooxygenase (COX) and prostaglandin E<SUB>2</SUB> (PGE<SUB>2</SUB>) protects cells against cell injury in specific pathophysiological situations: inflammation and oxidative stress. Although the anti-inflammatory effects have been reported in clinical fields for specific wavelength irradiation during wound healing, the physiological mechanism has not been clarified yet. The aim of the present study is to investigate the anti-inflammatory mechanism of 635 nm light-emitting-diode (LED) irradiation compared with existing COX inhibitors.</P><B>Study Design/Materials and Methods</B><P>The present study investigated anti-inflammatory effects of 635 nm irradiation on PGE<SUB>2</SUB> release, COX and phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>) expression, and reactive oxygen species (ROS) dissociation in arachidonic acid (AA)-treated human gingival fibroblast (hGF). These results were compared with their existing COX inhibitors: indomethacin and ibuprofen. The PGE<SUB>2</SUB> release was measured by enzyme immunoassay, the COX expression was measured by western blot and reverse transcriptase polymerase chain reaction (RT-PCR), and ROS level was measured by flow cytometry, laser scanning confocal microscope and RT-PCR.</P><B>Results</B><P>Results showed that 635 nm irradiation and existing COX inhibitors inhibit expression of COX and PGE<SUB>2</SUB> release. Unlike indomethacin and ibuprofen, 635 nm irradiation leads to a decrease of ROS levels and mRNA expression of cytosolic phospholipase A<SUB>2</SUB> (cPLA<SUB>2</SUB>) and secretary phospholipase A<SUB>2</SUB> (sPLA<SUB>2</SUB>).</P><B>Conclusion</B><P>Taken together, 635 nm irradiation, unlike indomethacin and ibuprofen, can directly dissociate the ROS. This inhibits cPLA<SUB>2</SUB>, sPLA<SUB>2</SUB>, and COX expression, and results in the inhibition of PGE<SUB>2</SUB> release. Thus, we suggest that 635 nm irradiation inhibits PGE<SUB>2</SUB> synthesis like COX inhibitor and appears to be useful as an anti-inflammatory tool. Lesers Surg. Med. 39:614–621, 2007. © 2007 Wiley-Liss, Inc.</P>

대학생의 직업윤리의식 함양 멘토링 프로그램

이원봉 ( Wonbong Lee ),이영 ( Young Lee ),박균열 ( Gyunyeol Park ) 인문사회 21 2023 인문사회 21 Vol.14 No.1

연구 목적: 이 연구는 대학생들에게 적용 가능한 직업윤리의식 함양 멘토링 프로그램을 개발함으로써 대학생들뿐만 아니라 대학의 직업교육의 내실있는 질적 관리에 기여하는 데 주안을 두었다. 연구 방법: 이 논문은 도덕심리학 분야에서 도덕성 측정 이론으로 많이 알려진 독일의 린트(G. Lind) 교수가 개발한 도덕판단역량검사도구(MCT: moral competence test)의 구성 알고리즘을 활용하였으며, 주로 문헌을 활용하는 문헌연구 방법을 채택하였다. 연구 내용: 이 논문은 MCT의 구성 알고리즘을 활용하여 직업윤리의식 함양을 위한 설문지를 개발하는 데 중점을 두었다. 대학생의 직업윤리의식을 함양하기 위한 멘토링 프로그램을 탐구하는 이론적, 실무적 내용을 다루었다. 결론 및 제언: 대학에서 직업교육을 위해 개발한 멘토링 프로그램을 통해서 취업준비 대학생들의 건전한 직업윤리의식을 고양할 수 있고, 대학의 직업윤리교육을 위한 비교과교육의 성과관리를 내실있게 할 수 있게 되었다. 다만 본 연구의 산출물인 “대학생 대상 직업윤리의식 함양 멘토링 프로그램”을 활용하여 실제로 대학생을 대상으로 한 수업을 실시하여 그 효용성을 확인하지 못한 한계점이 있어서, 향후에는 본 연구의 산출물인 “대학생 대상 직업윤리의식 함양 멘토링 프로그램”을 활용하여 실제로 대학생을 대상으로 한 수업을 실시하여 그 효용성을 확인하려고 한다. This paper aims to analyze and contribute to substantial quality management of vocational education in colleges as well as college students by developing a mentoring program for cultivating vocational ethics applicable to college students. This paper utilized the composition algorithm of the Moral Competence Test (MCT) developed by Professor G. Lind of Germany, who is well known for morality measurement theory in the field of moral psychology. The research method was adopted for this research. This paper focused on developing a questionnaire for the cultivation of professional ethics by utilizing the composition algorithm of MCT. The theoretical and practical contents of exploring the mentoring program for cultivating college students’ vocational ethical consciousness were dealt with. Through the quantifiable mentoring program for vocational education in universities, it is possible to enhance the sound professional ethics consciousness of college students preparing for employment, and to make the performance management substantial in non-subject education for vocational ethics education in universities.

Growth of Large-Scale and Thickness-Modulated MoS₂ Nanosheets

Choudhary, Nitin,Park, Juhong,Hwang, Jun Yeon,Choi, Wonbong American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.23

<P>Two-dimensional MoS<SUB>2</SUB> is a promising material for next-generation electronic and optoelectronic devices due to its unique electrical and optical properties including the band gap modulation with film thickness. Although MoS<SUB>2</SUB> has shown excellent properties, wafer-scale production with layer control from single to few layers has yet to be demonstrated. The present study explored the large-scale and thickness-modulated growth of atomically thin MoS<SUB>2</SUB> on Si/SiO<SUB>2</SUB> substrates using a two-step sputtering–CVD method. Our process exhibited wafer-scale fabrication and successful thickness modulation of MoS<SUB>2</SUB> layers from monolayer (0.72 nm) to multilayer (12.69 nm) with high uniformity. Electrical measurements on MoS<SUB>2</SUB> field effect transistors (FETs) revealed a <I>p</I>-type semiconductor behavior with much higher field effect mobility and current on/off ratio as compared to previously reported CVD grown MoS<SUB>2</SUB>-FETs and amorphous silicon (a-Si) thin film transistors. Our results show that sputter–CVD is a viable method to synthesize large-area, high-quality, and layer-controlled MoS<SUB>2</SUB> that can be adapted in conventional Si-based microfabrication technology and future flexible, high-temperature, and radiation hard electronics/optoelectronics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-23/am506198b/production/images/medium/am-2014-06198b_0006.gif'></P>

Injectable visible light-cured glycol chitosan hydrogels with controlled release of anticancer drugs for local cancer therapy <i>in vivo</i>: a feasible study

Hyun, Hoon,Park, Min Ho,Lim, Wonbong,Kim, So Yeon,Jo, Danbi,Jung, Jin Seok,Jo, Gayoung,Um, Sewook,Lee, Deok-Won,Yang, Dae Hyeok Informa UK (TaylorFrancis) 2018 Artificial cells, nanomedicine, and biotechnology Vol.46 No.suppl2

Chemoresistance to 5-FU inhibited by 635 nm LED irradiation in CD133+ KB cell line

Kim, Donghwi,Park, Mineon,Jang, Hyunwoong,Hyun, Hoon,Lim, Wonbong Springer-Verlag 2018 LASERS IN MEDICAL SCIENCE Vol.33 No.1

<P>Consistent with cancer stem cell theory, a small fraction of cancer cells, described as cancer stem cells (CSCs), may promote tumor recurrence and anti-cancer drug resistance. Therefore, much effort has been devoted to the development of CSC targeted therapy to vanquish drug resistance. In this study, we have investigated the effect of multiple light-emitting diode (LED) irradiation treatments with conventional anti-cancer drugs on CSC-like oral cancer cells that acquired stemness by ectopic over expression of CD133. To evaluate combined LED irradiation anti-cancer drug effects, we investigated the chemosensitizing effect of 635 nm irradiation on 5-fluorouracil (5FU)-treated KBCD133+ and KBVec cells, interrogating the underlying molecular mechanisms associated with stemness and apoptosis that are responsible for chemopreventive activity. In addition, combination therapy with LED irradiation and 5-FU treatment was carried out in KBCD133+ and KBVec cell-inoculated mouse models. LED irradiation of 635 nm inhibited CSC-like properties consistent with a decrease in OCT4 and NANOG protein expression, reducing colony-forming ability. In addition, LED irradiation enhanced 5-FU-induced cytotoxicity and improved 5-FU chemosensitivity in KBCD133+ via enhancement of apoptosis. These findings were validated in vivo, wherein LED irradiation combined with 5-FU treatment inhibited tumor growth in KBCD133+-inoculated mice. Collectively, our results provide novel evidence for 635 nm irradiation-induced 5-FU chemosensitization of CSC in oral cancer. In addition, this research highlights that 635 nm LED irradiation may serve as an adjunct treatment to conventional chemotherapeutic drugs in patients with oral cancer.</P>

Aloe vera gel enhanced in vitro antimicrobial activity of propolis against oral pathogens

Shim ChangSup,Park WonBong,Kim JongHyun,Rhim JeeYoung,Jung SeungHee,Moon YouSun,Lee GyuYim,Lyu SuYun 大韓藥學會 2001 大韓藥學會 總會 및 學術大會 Vol.2001 No.2