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The Cause of Institutionalized Private Tutoring in Korea:Defective Public Schooling or a Universal Desire for Family Reproduction?

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ECNU Review of Education 2024年第1期7卷 12-41页

作者： Sang hoon Bae Kee ho choi Sungkyunkwan University Seoul National University

Purpose:In Korea,private tutoring is considered a social evil that damages the capacity of public schooling and undermines social *** the government has implemented various policies to reduce private tutoring,ranging from improving the quality of education to providing"quasi-private tutoring"programs and regulating the shadow education market,total spending on private tutoring has continued to *** study examines a little noticed but important cause of institutionalized private tutoring in ***/Approach/Methods:The study employed a socio-ecological perspective to analyze both education and socio-structural *** extensive review of the government's private tutoring reduction policies and related literature was ***:Private tutoring functions as a means by which parents can help their children compete for admission to prestigious universities and pass on wealth and social status to their *** in private tutoring has become a social norm that is taken for *** root causes of institutionalized private tutoring lie in both educational and socio-structural ***/Nalue:The study suggests that government policies,when ignoring the long-established"grammar"of parents about children's education,may either end in failure or produce unintended consequences.

关键词： Private tutoring social reproduction unintended consequences upward mobility

Atomically Adjustable Rhodium Catalyst Synthesis with Outstanding Mass Activity via Surface-Li mi ted Cation Exchange

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Energy & Environmental Materials 2024年第2期7卷 83-92页

作者： Hak Hyeon Lee Dong Su Kim Swagotom Sarker Ji hoon choi ho Seong Lee Hyung Koun Cho Department of Advanced Materials Science&Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-doSeoul 16419Korea Department of Advanced Materials Science&Engineering Kyungpook National University80Daehak-roBuk-guDaegu 41566Korea

Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing *** Rh being expensive,only a few studies have examined its electrocatalytic mass ***,surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of *** atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange,and the resulting RhoOH compounds were activated by the electrochemical reduction *** cation exchange-derived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration,indicating a decrease in the number of inactive inner Rh ***,an improved mass activity of 30 A mg_(Rh)^(-1)was achieved at 0.4 V versus reversible hydrogen ***,the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low *** proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.

关键词： cation exchange synthesis electrochemical metallization hydrazine oxidation reaction mass activity rhodium catalyst

ELK3-ID4 axis governs the metastatic features of triple negative breast cancer

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Oncology Research 2024年第1期32卷 127-138页

作者： JIN-ho choi JOO DONG PARK SEUNG HEE choi EUN-SU KO HYE JUNG JANG KYUNG-SOON PARK Department of Biomedical Science CHA UniversitySeongnamKorea

Purpose:Cancer cell metastasis is a multistep process,and the mechanism underlying extravasation remains ***3 is a transcription factor that plays a crucial role in regulating various cellular processes,including cancer *** on the finding that ELK3 promotes the metastasis of triple-negative breast cancer(TNBC),we investigated whether ELK3 regulates the extravasation of TNBC by forming the ELK3-ID4 ***4 functions as a transcriptional regulator that interacts with other transcription factors,inhibiting their activity and subsequently influencing various biological processes associated with cell differentiation,survival,growth,and ***:We assessed the correlation between the expression of ELK3 and that of ID4 in TNBCs using bioinformatics analyses,QRT-PCR,western blot analysis,luciferase reporter assays,and chromatin ***,adhesion,invasion,and lung metastasis assays were employed to determine whether the ELK3-ID4 axis regulates the metastatic features of ***:We found that ELK3 binds directly to a binding motif close to the ID4 promoter to repress promoter *** expression of E-cadherin in TNBC was regulated by the ELK3-ID4 *** vitro and in vivo analyses showed that inhibiting ID4 expression in ELK3-knockdown MDA-MB-231(ELK3KD)cells restored the ability to extravasate and ***:The results indicate that the ELK3 regulates ID4 promoter activity,and that the ELK3-ID4 axis regulates the metastatic characteristics of TNBC ***,the data suggest that the ELK3-ID4 axis regulates metastasis of TNBCs by modulating expression of E-cadherin.

关键词： E-cadherin Extravasation Colonization

A Cu-Pd alloy catalyst with partial phase separation for the electrochemical CO_(2) reduction reaction

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Journal of Energy Chemistry 2024年第6期93卷 8-15,I0001页

作者： Gyeong ho Han Jung Yong Seo Minji Kang Myung-gi Seo Youngheon choi Soo Young Kim Sang Hyun Ahn School of Chemical Engineering and Material Science Chung-Ang UniversitySeoul 06974Republic of Korea Lotte Chemical Institute of Technology Daejeon 34110Republic of Korea Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea

Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based ***,this capability provides an obstacle to increasing the selectivity for a single ***,we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly(MEA)-based CO_(2) electrolyzer for the electrochemical CO_(2) reduction reaction(ECRR)with high selectivity for CO *** the composition of the Cu-Pd alloy catalyst was fabricated at 6:4,the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is *** a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEAbased CO_(2) electrolyzer showed a CO faradaic efficiency of 92.8%at 2.4 V_(cell).We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd *** phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C_(2)H_4 at high *** results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy,the desorption of~*CO is suppressed,suggesting that C-C coupling reaction is favored.

关键词： Cu-Pd catalyst Electrodeposition Electrochemical carbon dioxide reduction Partial phase separation Membrane electrode assembly-based electrolyzer

A dose-dependent bimodal switch by homologous Aux/IAA transcriptional repressors

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Molecular Plant 2024年第9期17卷 1407-1422页

作者： Hyung-Taeg Cho Minsu Lee Hee-Seung choi Kwang-ho Maeng Kyeonghoon Lee Ha-Yeon Lee Anindya Ganguly hoonyoung Park Chang-hoi ho Department of Biological Sciences Seoul National UniversitySeoulKorea School of Earth and Environmental Sciences Seoul National UniversitySeoulKorea Department of Climate and Energy Systems Engineering Ewha Womans UniversitySeoulKorea

Combinatorial interactions between different regulators diversify and enrich the chance of transcriptional regulation in eukaryotic ***,a dose-dependent functional switch of homologous transcriptional repressors has rarely been ***,we show that SHY2,an auxin/indole-3-acetic acid(Aux/IAA)repressor,exhibits a dose-dependent bimodal role in auxin-sensitive root-hair growth and gene transcrip-tion in Arabidopsis,whereas other Aux/lAA homologs consistently repress the auxin *** co-repressor(TOPLESS[TPL])-binding affinity of a bimodal Aux/IAA was lower than that of a consistently re-pressing Aux/*** switch of a single amino acid residue in the TPL-binding motif between the bimodal form and the consistently repressing form switched their TPL-binding affinity and transcriptional and bio-logical roles in auxin *** on these data,we propose a model whereby competition between homologous repressors with different co-repressor-binding affinities could generate a bimodal output at thetranscriptional anddevelopmental levels.

关键词： auxin Aux/IAA dose-dependent regulation root hair transcription TOPLESS(TPL)

Trifunctional robust electrocatalysts based on 3D Fe/N-doped carbon nanocubes encapsulating Co4N nanoparticles for efficient battery-powered water electrolyzers

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Carbon Energy 2024年第6期6卷 124-139页

作者： Hyung Wook choi hongdae Lee Jun Lu Seok Bin Kwon Dong In Jeong Beum Jin Park Jiwon Kim Bong Kyun Kang Gun Jang Dae ho Yoon ho Seok Park SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Chemical Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Electronic Materials Devicesand Equipment EngineeringSoonchunhyang UniversityAsan CityChungnamRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwonRepublic of Korea

Herein,we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs,where Co_(4)N nanoparticles are encapsulated by Fe embedded in N-doped carbon nanocubes to synthesize hierarchically structured Co_(4)N@Fe/N-C for rechargeable zinc-air batteries and overall water-splitting *** confirmed by theoretical and experimental results,the high intrinsic oxygen reduction reaction,oxygen evolution reaction,and hydrogen evolution reaction activities of Co_(4)N@Fe/N-C were attributed to the formation of the heterointerface and the modulated local electronic ***,Co_(4)N@Fe/N-C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure,uniform distribution of Co_(4)N,and conductive encapsulation by Fe/***,the rechargeable zinc-air battery with Co_(4)N@Fe/N-C delivers a high specific capacity of 789.9 mAh g^(-1) and stable voltage profiles over 500 ***,the overall water electrolyzer with Co_(4)N@Fe/N-C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts,delivering a high Faradaic efficiency of 96.4%.Along with the great potential of the integrated water electrolyzer powered by a zinc-air battery for practical applications,therefore,the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

关键词： battery-powered electrolyzers hierarchical structure Prussian blue analog trifunctional electrocatalyst zinc-air battery

Flower morphology of Allium(Amaryllidaceae)and its systematic significance

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Plant Diversity 2024年第1期46卷 3-27页

作者： Ju Eun Jang Shukherdorj Baasanmunkh Nudkhuu Nyamgerel Seung-Yoon Oh Jun-ho Song Ziyoviddin Yusupov Komijlon Tojibaev Hyeok Jae choi Department of Biology and Chemistry Changwon National UniversityChangwon51140Republic of Korea Department of Forest Biodiversity and Herbarium Korea National ArboretumPocheon11186Republic of Korea Department of Biology Chungbuk National UniversityCheongju28644Republic of Korea International Joint Lab for Molecular Phylogeny and Biogeography Institute of BotanyAcademy of Sciences of UzbekistanTashkent100125Uzbekistan

Allium is a complicated genus that includes approximately 1000 *** its morphology is well studied,the taxonomic importance of many morphological traits,including floral traits,are poorly ***,we examined and measured the floral characteristics of 87 accessions of 74 Allium taxa(belonging to 30 sections and nine subgenera)from Central to Eastern Asian *** then examined the taxonomic relationships between select flower characteristics and a phylogenetic tree based on ITS *** results confirm that floral morphology provides key taxonomic information to assess species delimitation in *** found that perianth color is an important characteristic within the ***,Polyprason,and *** ***,Cepa,and Rhizirideum,significant characteristics include ovary shape,perianth shape,and inner tepal *** species in ***,the key taxonomic character is ovule number(only one ovule in per locule).In the ***,Cepa,Polyprason,and Reticulatobulbosa,which belong to the third evolutionary line of Allium,hood-like appendages occur in the ovary,although these do not occur in *** results also indicated that the flower morphology of several species in some sections are not clearly distinguished,e.g.,***(***)and ***(***).This study provides detailed photographs and descriptions of floral characteristics and information on general distributions,habitats,and phenology of the studied taxa.

关键词： Allium Flower morphology Pistil character Statistical analysis Significant characteristic Species level

Unraveling the Harmonious Coexistence of Ruthenium States on a Self-Standing Electrode for Enhanced Hydrogen Evolution Reaction

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 303-311页

作者： Ma, Joonhee Cho, Jin Hyuk Lee, Chaehyeon Kang, Moon Sung choi, Sungkyun Jang, ho Won Ahn, Sang Hyun Back, Seoin Kim, Soo Young Korea Univ Dept Mat Sci & Engn Seoul 02841 South Korea Sogang Univ Inst Emergent Mat Dept Chem & Biomol Engn Seoul 04107 South Korea Pusan Natl Univ Coll Nanosci & Nanotechnol Dept Cogno Mechatron Engn Busan 46241 South Korea Seoul Natl Univ Res Inst Adv Mat Dept Mat Sci & Engn Seoul 08826 South Korea Chung Ang Univ Sch Chem Engn & Mat Sci Seoul 06974 South Korea

The development of cost-effective, highly efficient, and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction (HER). Herein, a simplified synthesis protocol was designed to achieve a self-standing electrode, composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters (ACP/RuSAC+C) via acid activation, immersion, and high-temperature pyrolysis. Ab initio molecular dynamics (AIMD) calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper. Furthermore, the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect, tuning the electronic structure and thereby significantly enhancing their catalytic performance. Notably, the ACP/RuSAC+C exhibits a remarkable turnover frequency (TOF) of 18 s-1 and an exceptional mass activity (MA) of 2.2 A mg-1, surpassing the performance of conventional Pt electrodes. The self-standing electrode, featuring harmoniously coexisting Ru states, stands out as a prospective choice for advancing HER catalysts, enhancing energy efficiency, productivity, and selectivity. A self-standing electrode with the coexistence of Ru single atoms and Ru nanoclusters is designed for the hydrogen evolution reaction (HER). Additional acid activation process induces defects, anchoring more Ru ions on the substrate. Detailed experimental and computational investigations suggest that the electronic coupling effect between different Ru states significantly enhanced the overall HER performance. image

关键词： electrocatalysis electronic coupling effect hydrogen evolution reaction self-standing electrode CARBON ELECTROREDUCTION CATALYSTS PAPER

Superconducting joints using reacted multifilament MgB_(2)wires:A technology toward cryogen-free MRI magnets

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Journal of Magnesium and Alloys 2024年第1期12卷 159-170页

作者： Dipak Patel Akiyoshi Matsumoto Hiroaki Kumakura Yuka Hara Toru Hara Minoru Maeda Hao Liang Yusuke Yamauchi Seyong choi Jung ho Kim Md Shahriar A.hossain School of Mechanical and Mining Engineering The University of QueenslandSt LuciaQueensland 4072Australia National Institute for Materials Science(NIMS) 1-2-1 SengenTsukubaIbaraki 305-0047Japan Department of Electrical Engineering and Kangwon High Magnetic Field Center Institute of Quantum Convergence TechnologyKangwon National UniversityGangwon 24341Republic of Korea Australian Institute for Bioengineering and Nanotechnology(AIBN) The University of QueenslandSt LuciaQueensland 4072Australia Department of Materials Process Engineering Graduate School of EngineeringNagoya UniversityNagoyaAichi 464-8603Japan Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongNorth WollongongNew South Wales 2500Australia

The development of superconducting joining technology for reacted magnesium diboride(MgB_(2))conductors remains a critical challenge for the advancement of cryogen-free MgB_(2)-based magnets for magnetic resonance imaging(MRI).Herein,the fabrication of superconducting joints using reacted carbon-doped multifilament MgB_(2)wires for MRI magnets is *** achieve successful superconducting joints,the powder-in-mold method was employed,which involved tuning the filament protection mechanism,the powder compaction pressure,and the heat treatment *** fabricated joints demonstrated clear superconducting-to-normal transitions in self-field,with effective magnetic field screening up to 0.5 T at 20 *** evaluate the interface between one of the MgB_(2)filaments and the MgB_(2)bulk within the joint,serial sectioning was conducted for the first time in this type of superconducting *** serial sectioning revealed space formation at the interface,potentially caused by the volume shrinkage associated with the MgB_(2)formation or the combined effect of the volume shrinkage and the different thermal expansion coefficients of the MgB_(2)bulk,the filament,the mold,and the sealing *** findings are expected to be pivotal in developing MgB_(2)superconducting joining technology for MRI magnet applications through interface engineering.

关键词： Mg B2 superconducting joint MgB_(2)conductor MRI applications Cryogen-free magnet Persistent-mode operation