Simple Electrodeposition of Dendritic Pd Without Supporting Electrolyte and Its Electrocatalytic Activity Toward Oxygen Reduction and H₂O₂ Sensing

Kang, Minkyung,Yang, Yejin,Shim, Jun Ho,Lee, Sang Cheol,Lee, Youngmi,Lee, Chongmok WILEY‐VCH Verlag 2013 Electroanalysis Vol.25 No.12

<P><B>Abstract</B></P><P>Metallic palladium (Pd) electrocatalysts for oxygen reduction and hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) oxidation/reduction are prepared via electroplating on a gold metal substrate from dilute (5 to 50 mM) aqueous K<SUB>2</SUB>PdCl<SUB>4</SUB> solution. The best Pd catalyst layer possessing dendritic nanostructures is formed on the Au substrate surface from 50 mM Pd precursor solution (denoted as Pd‐50) without any additional salt, acid or Pd templating chemical species. The Pd‐50 consisted of nanostructured dendrites of polycrystalline Pd metal and micropores within the dendrites which provide high catalyst surface area and further facilitate reactant mass transport to the catalyst surface. The electrocatalytic activity of Pd‐50 proved to be better than that of a commercial Pt (Pt/C) in terms of lower overpotential for the onset and half‐wave potentials and a greater number of electrons (<I>n</I>) transferred. Furthermore, amperometric <I>i</I>–<I>t</I> curves of Pd‐50 for H<SUB>2</SUB>O<SUB>2</SUB> electrochemical reaction show high sensitivities (822.2 and −851.9 µA mM<SUP>−1</SUP> cm<SUP>−2</SUP>) and low detection limits (1.1 and 7.91 µM) based on H<SUB>2</SUB>O<SUB>2</SUB> oxidation H<SUB>2</SUB>O<SUB>2</SUB> reduction, respectively, along with a fast response (<1 s).</P>

Clinical evaluation of cetylpyridinium chloride- containing mouthwash in halitosis

Minkyung Kang,Boyeon Kim,Hyounggeun Park,Eunseok Lee 대한구강생물학회 2019 International Journal of Oral Biology Vol.44 No.1

Halitosis is a very common disease that affects the majority of the population and is characterized by unpleasant odor during expiration. Anaerobic bacteria produce a range of malodorous substances including volatile sulfur compounds. To reduce oral malodor, the amount of oral microorganisms should be managed through brushing, scraping, and use of antibacterial agents. In this study, a mouthwash containing 0.05% cetylpyridinium chloride was tested on 22 candidates with oral malodor for two weeks to confirm oral malodor reduction through the use of antibacterial mouthwashes. Volatile sulfur compound measurements were significantly lower after using the mouthwash than before using it; thus, the mouthwash effectively reduced oral malodor.

Cross-talk between TGFβ1 and EGFR signalling pathways induces TM4SF5 expression and epithelial-mesenchymal transition.

Kang, Minkyung,Choi, Suyong,Jeong, Soo-Jin,Lee, Sin-Ae,Kwak, Tae Kyoung,Kim, Hyeonjung,Jung, Oisun,Lee, Mi-Sook,Ko, Youra,Ryu, Jihye,Choi, Yoon-Ju,Jeong, Doyoung,Lee, Hyo Jeong,Ye, Sang-Kyu,Kim, Sung- Biochemical Society 2012 The Biochemical journal Vol.443 No.3

<P>The EMT (epithelial-mesenchymal transition) is involved in fibrosis and cancer, and is regulated by different signalling pathways mediated through soluble factors, actin reorganization and transcription factor actions. Because the tetraspan (also called tetraspanin) TM4SF5 (transmembrane 4 L6 family member 5) is highly expressed in hepatocellular carcinoma and induces EMT, understanding how TM4SF5 expression in hepatocytes is regulated is important. We explored the mechanisms that induce TM4SF5 expression and whether impaired signalling pathways for TM4SF5 expression inhibit the acquisition of mesenchymal cell features, using human and mouse normal hepatocytes. We found that TGFβ1 (transforming growth factor β1)-mediated Smad activation caused TM4SF5 expression and EMT, and activation of the EGFR [EGF (epidermal growth factor) receptor] pathway. Inhibition of EGFR activity following TGFβ1 treatment abolished acquisition of EMT, suggesting a link from Smads to EGFR for TM4SF5 expression. Further, TGFβ1-mediated EGFR activation and TM4SF5 expression were abolished by EGFR suppression or extracellular EGF depletion. Smad overexpression mediated EGFR activation and TM4SF5 expression in the absence of serum, and EGFR kinase inactivation or EGF depletion abolished Smad-overexpression-induced TM4SF5 and mesenchymal cell marker expression. Inhibition of Smad, EGFR or TM4SF5 using Smad7 or small compounds also blocked TM4SF5 expression and/or EMT. These results indicate that TGFβ1- and growth factor-mediated signalling activities mediate TM4SF5 expression leading to acquisition of mesenchymal cell features, suggesting that TM4SF5 induction may be involved in the development of liver pathologies.</P>

Single Carbon Fiber Decorated with RuO₂ Nanorods as a Highly Electrocatalytic Sensing Element

Kang, Minkyung,Lee, Yumin,Jung, Hayoung,Shim, Jun Ho,Lee, Nam-Suk,Baik, Jeong Min,Lee, Sang Cheol,Lee, Chongmok,Lee, Youngmi,Kim, Myung Hwa American Chemical Society 2012 ANALYTICAL CHEMISTRY - Vol.84 No.21

<P>We demonstrate highly efficient electocatalytic activities of single crystalline RuO<SUB>2</SUB> nanorods grown on carbon fiber (CF), i.e., RuO<SUB>2</SUB> nanorod-CF hybrid microelectrode, prepared by a simple thermal annealing process from the Ru(OH)<SUB>3</SUB> precursor at 300 °C. The general electrochemical activity of a RuO<SUB>2</SUB> nanorod-CF microelectrode represents faster electron transfer for the [Fe(CN)<SUB>6</SUB>]<SUP>3–/4–</SUP> couple than that of the bare CF microelectrode which are confirmed from the cyclic voltammetry (CV) measurement. Also, the amperometric response for the H<SUB>2</SUB>O<SUB>2</SUB> oxidation is remarkably facilitated at the RuO<SUB>2</SUB> nanorod-CF microelectrode by not only the enlarged surface area but the high electrocatalytic activity of the RuO<SUB>2</SUB> nanorod material itself. Furthermore, a single microelectrode of RuO<SUB>2</SUB> nanorod-CF exhibits the superior tolerance to Cl<SUP>–</SUP> ion poisoning unlike Pt-based electrocatalysts, indicating the promising sensor candidate in physiological conditions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2012/ancham.2012.84.issue-21/ac302334t/production/images/medium/ac-2012-02334t_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac302334t'>ACS Electronic Supporting Info</A></P>

Antagonistic regulation of transmembrane 4 L6 family member 5 attenuates fibrotic phenotypes in CCl₄‐treated mice

Kang, Minkyung,Jeong, Soo‐,Jin,Park, Sook Young,Lee, Hyo Jeong,Kim, Hyun Jeong,Park, Ki Hun,Ye, Sang‐,Kyu,Kim, Sung‐,Hoon,Lee, Jung Weon Blackwell Publishing Ltd 2012 FEBS JOURNAL Vol.279 No.4

<P>The development of liver fibrosis from chronic inflammation can involve epithelial–mesenchymal transition (EMT). Severe liver fibrosis can progress to cirrhosis, and further to hepatocellular carcinoma. Because the tetraspanin transmembrane 4 L6 family member 5 (TM4SF5) induces EMT and is highly expressed in hepatocellular carcinoma, it is of interest to investigate whether TM4SF5 expression is correlated with EMT processes during the development of fibrotic liver features. Using hepatic cells <I>in vitro</I> and a CCl<SUB>4</SUB>‐mediated mouse liver <I>in vivo</I> model, we examined whether TM4SF5 is expressed during liver fibrosis mediated by CCl<SUB>4</SUB> administration and whether treatment with anti‐TM4SF5 reagent blocks the fibrotic liver features. Here, we found that TM4SF5 expression was induced by the transforming growth factor (TGF)β1 and epidermal growth factor signaling pathways in hepatocytes <I>in vitro</I>. In the CCl<SUB>4</SUB>‐mediated mouse liver model, TM4SF5 was expressed during the liver fibrosis mediated by CCl<SUB>4</SUB> administration and correlated with α‐smooth muscle actin expression, collagen I deposition, and TGFβ1 and epidermal growth factor receptor signaling activation in fibrotic septa regions. Interestingly, treatment with anti‐TM4SF5 reagent blocked the TM4SF5‐mediated liver fibrotic features: the formation of fibrotic septa with α‐smooth muscle actin expression and collagen I deposition was attenuated by treatment with anti‐TM4SF5 reagent. These results suggest that TM4SF5 expression mediated by TGFβ1 and growth factor can facilitate fibrotic processes during chronic liver injuries. TM4SF5 is thus a candidate target for prevention of liver fibrosis following chronic liver injury.</P>

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

Kang, Minkyung,Perry, David,Kim, Yang-Rae,Colburn, Alex W.,Lazenby, Robert A.,Unwin, Patrick R. American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.34

<P>There is considerable interest in understanding the interaction and activity of single entities, such as (electro)catalytic nanoparticles (NPs), with (electrode) surfaces. Through the use of a high bandwidth, high signal/noise measurement system, NP impacts on an electrode surface are detected and analyzed in unprecedented detail, revealing considerable new mechanistic information on the process. Taking the electrocatalytic oxidation of H<SUB>2</SUB>O<SUB>2</SUB> at ruthenium oxide (RuO<SUB><I>x</I></SUB>) NPs as an example, the rise time of current–time transients for NP impacts is consistent with a hydrodynamic trapping model for the arrival of a NP with a distance-dependent NP diffusion-coefficient. NP release from the electrode appears to be aided by propulsion from the electrocatalytic reaction at the NP. High-frequency NP impacts, orders of magnitude larger than can be accounted for by a single pass diffusive flux of NPs, are observed that indicate the repetitive trapping and release of an individual NP that has not been previously recognized. The experiments and models described could readily be applied to other systems and serve as a powerful platform for detailed analysis of NP impacts.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2015/jacsat.2015.137.issue-34/jacs.5b05856/production/images/medium/ja-2015-05856p_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja5b05856'>ACS Electronic Supporting Info</A></P>

Comparisons of behavior and synaptic plasticity among three C57BL/6 substrains

Kang, Minkyung,Ryu, Hyun-Hee,Lee, Yong-Seok Taylor Francis 2015 Animal cells and systems Vol.19 No.3

장애아동을 대상으로 한 로봇활용 연구의 최근 동향

강민경(Kang, minkyung),이현정(Lee, hyunjung),김영태(Kim, youngtae) 이화여자대학교 특수교육연구소 2013 특수교육 Vol.12 No.3

본 연구에서는 국내외에서 이루어진 장애아동을 대상으로 한 로봇 활용 연구의 동향을 살펴보고, 이를 분석하여 정리하였으며, 이를 기초로 추후 장애아동을 대상으로 하는 로봇활용연구의 방향을 제시하고자 하였다. 이를 위하여 2000년 이후에 발표된 논문을 체계적으로 검색하여 논문 선정 기준에 맞는 총 37편의 연구 논문을 선정하였고, 연구 대상자의 연령, 연구방법, 독립변인, 종속변인 유형을 바탕으로 하여 분석하였다. 연구대상자인 장애아동의 연령은 20개월부터 20세 6개월까지로 매우 넓게 분포되어 있었으며, 연구유형별로는 문헌 연구 7편, 중재연구 12편, 특성 연구 18편, 비교연구 1편으로 나타났다. 독립변인은 로봇 사용 유무에 따른 연구가 대부분이었고, 종속변인은 크게 4가지로 분류하여 분석하였다. 또한 의사소통증진을 위한 로봇활용 연구의 필요성을 제안하였다. Background & Objectives: The purpose of the present study was to critically review the existing literature on the uses of robots for children with disabilities. Methods: Thirty-seven studies were reviewed according to participants, research methods, dependent variables, and independent variables. Results: Results revealed that (1) children’s ages ranged from 20 months to 20 years 6 months; (2) there were seven literature reviews, twelve intervention studies, eignteen characteristics studies, and a comparative study, respectively; and (3) dependent measures were organized into four categories and analyzed. Discussion & Conclusion: Based on the results from the research, the implications for further studies on the uses of robots for children with disabilities were suggested.

메타분석을 통한 자폐범주성장애의 어휘처리 양상 연구

강민경(Minkyung Kang),이수복(Soobok Lee),김영태(Young Tae Kim),임동선(Dongsun Yim) 한국언어청각임상학회 2012 Communication Sciences and Disorders Vol.17 No.2

배경 및 목적: 자폐범주성장애(ASD) 그룹의 어휘처리 능력은 그들의 다른 언어 능력에 비해 습득 및 발달상의 특이성을 가지고 있다. ASD 그룹의 어휘처리 능력이 통제 그룹과 비슷한지 또는 차이를 보이는지에 대해서는 ASD의 하위유형 중 어떤 집단을 연구대상자로 하였는지, 자극 제시 조건은 어떠하였는지, 대상자에게 실시되는 과제 유형은 무엇이었는지에 따라 다르게 나타날 수 있다. 본 연구는 메타분석을 통해 현재까지 이루어진 ASD 그룹의 어휘처리능력을 체계적으로 검토하고, 통제 그룹과 비교하여 수행차이를 보이는지에 대해 알아보고자 한다. 방법: 주제어를 통해 국외 관련문헌을 검토한 후 연구의 포함과 제외기준에 따라 체계적으로 14개의 문헌을 선정하였다. ASD 그룹의 어휘처리능력에 대한 효과크기는 무선효과모델(random effect model)을 사용하여 산출하였다. 결과: ASD 그룹의 어휘처리능력에 대한 연구는 고기능자폐, 아스퍼거증후군을 대상으로 많이 이루어졌고, 과제유형은 단어재인과제와 어휘판단과제를 가장 많이 사용하는 것으로 나타났다. 연구결과는 첫째, ASD 그룹은 전반적인 어휘처리능력이 통제 그룹과 차이가 없는 것으로 나타났다. 둘째, 두 가지 자극 제시 조건에서의 그룹간 차이에서도 ASD 그룹과 통제 그룹간의 차이는 없는 것으로 나타났다. 마지막으로 ASD 그룹은 어휘처리 과제 유형에 따라 수행력의 차이를 보이지 않았다. 논의 및 결론: ASD 그룹의 어휘처리 능력은 그 ASD의 하위영역에 따라 차이를 보일 수 있으나, 대부분의 영역에서는 통제 그룹과 차이를 보이지 않는 것으로 나타났다. 이러한 결과를 바탕으로 ASD 그룹의 어휘 중재에 대한 근거를 제공할 수 있을 것이다. Background & Objectives: The lexical processing of groups with Autism spectrum disorders(ASD) has specificity in comparisonto their other language skill. Therefore, it is difficult to obtain consistent results for lexical processing in groups with ASD. The results can vary depending on the subgroups of ASD, stimuli modes, and task types. The purpose of this meta-analysis study was to systematically investigate the results of previous studies on the lexical processing ability in groups with ASD. Methods: Using Meta-Analysis(CMA2, Comprehensive Meta-Analysis-Ⅱ, 2005), a systematic literature review approach was taken. There were 14 studies which met the inclusive and exclusive criteria of our research. The effect sizes for ASDs and overall typical developmental(TD) abilities for lexical processing were analyzed via a random effect model. Results: The results of this study revealed that word recognition and lexical decisions were the most commonly used tasks. In addition, the general target populations for lexical processing were high functioning autism(HFA) and Asperger’ syndrome(AS). There were three main findings from our study results. First, the meta-analysis results indicated that the overall lexical processing abilities were not significantly different between ASD and TD. Second, there were no significant differences in the results based on stimuli modes. Lastly, there were no significant differences in the results depending on the task types. Discussion & Conclusion: Our findings suggest that there was not a significant difference between the ASD’ and TD’ overall lexical processing abilities. Therefore, the results should provide an evidence-based rationale for the ASD group’ vocabulary intervention.

천부빙하와 눈에서 황산염 동위원소에 대한 고찰

강민경(Minkyung Kang),이정훈(Jeonghoon Lee) 대한지질학회 2016 대한지질학회 학술대회 Vol.2016 No.10