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Modulating the synergy of Pd@Pt core-shell nanodendrites for boosting methanol electrooxidation kinetics

Journal of Materials Science & Technology 2023年第34期165卷 153-160页

作者： hyeon jeong kim Cheol Joo Moon Seokhee Lee Jayaraman Theerthagiri Jong Wook Hong Myong Yong Choi Young Wook Lee Department of Chemistry and Research Institute of Natural Sciences Gyeongsang National UniversityJinju 52828Republic of Korea Core-Facility Center for Photochemistry&Nanomaterials Gyeongsang National UniversityJinju 52828Republic of Korea Energy&Environment Division Korea Institute of Ceramic Engineering and Technology(KICET)Jinju 52851Republic of Korea Department of Chemistry University of UlsanUlsan 44610Republic of Korea Department of Education Chemistry and Research Institute of Natural Sciences Gyeongsang National UniversityJinju 52828Republic of Korea

The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and *** this work,we established a single-pot process to produce Pd@Pt core-shell nanodendrites with tunable composition,shape and size for optimal electrochemical ***@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride,which functioned as both the surfactant and the reducing agent at an elevated temperature(90°C).The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C *** addition,Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and ***,nanodendrites with a Pt-rich surface provided exceptional catalytic active *** with the conventional Pt/C electrocatalyst,the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density,*** approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion.

关键词： Core-shell nanostructure Pd@Pt electrocatalysis One-pot synthesis Formation mechanism of nanodendrites Methanol oxidation reaction

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Effects of feeding a diet containing Gymnema sylvestre extract: attenuating progression of obesity in C57BL/6J mice

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Asian Pacific Journal of Tropical Medicine 2016年第5期9卷 425-431页

作者： hyeon-jeong kim Seong-Ho Hong Seung-Hee Chang Sanghwa kim Ah Young Lee Yoonjeong Jang Orkhonselenge Davaadamdin Kyeong-Nam Yu Ji-Eun kim Myung-Haing Cho Laboratory of Toxicology College of Veterinary Medicine Seoul National University Graduate Group of Tumor Biology Seoul National University Graduate School of Convergence Science and Technology Seoul National University Advanced Institutes of Convergence Technology Seoul National University Institute of Green Bio Science Technology Seoul National University

Objective: To investigate the effect of Gymnema sylvestre extract(GS) on initial anti-obesity, liver injury, and glucose homeostasis induced by a high-fat diet(HFD). Methods: The dry powder of GS was extracted with methanol, and gymnemic acid was identified by high performance liquid chromatography as deacyl gymnemic acid. Male C57BL/6J mice that fed on either a normal diet, normal diet containing 1 g/kg GS(CON+GS) HFD, or HFD containing 1.0 g/kg GS(HFD+GS) for 4 weeks were used to test the initial anti-obesity effect of GS. Body weight gain and food intake, and serum levels about lipid and liver injury markers were measured. Histopathology of adipose tissue and liver stained with hematoxylin and eosin(H&E) and oil-red O were analyzed. After 4 weeks of GS extract feeding, intraperitoneal glucose tolerance test(IPGTT) was performed. Results: The methanol extracts of GS exerted significant anti-obesity effects in HFD+GS group. They decreased body weight gain, a lower food and energy efficiency ratio, and showed lower serum levels of total cholesterol(TC), triglyceride(TG), low-density lipoprotein(LDL)-cholesterol, very-low density lipoprotein(VLDL)-cholesterol and leptin compared with the HFD group. The decreases of abdominal as well as epididymal fat weight and adipocyte hypertrophy, lipid droplets in liver, and serum levels of aspartate aminotransferase(AST) and alanine transaminase(ALT) were also observed. The CON+GS group showed an effect of glucose homeostasis compared to the CON group. Conclusions: This study shows that GS provide the possibility as a key role in an initial anti-obesity effects feeding with a HFD.

关键词： Gymnema sylvestre extract Obesity Adipocyte Body weight gain High-fat diet Liver injury

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Identification and comparison of the local physicochemical structures of transition metal-based layered double hydroxides for high performance electrochemical oxygen evolution reactions

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Journal of Energy Chemistry 2023年第12期87卷 89-97,I0004页

作者： Min Sung kim Bipin Lamichhane Ju-hyeon Lee Jin-Gyu Bae jeong Yeon Heo hyeon jeong Lee Shyam Kattel Ji Hoon Lee School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea KNU Advanced Material Research Institute Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Department of Physics Florida A&M UniversityTallahasseeFlorida 32307United States

Layered double hydroxides(LDHs) have attracted considerable attention as a cost effective alternative to the precious iridium-and ruthenium-based electrocatalysts for an oxygen evolution reaction(OER),a bottleneck of water electrolysis for sustainable hydrogen *** their excellent OER performance,the structural and electronic properties of LDHs,particularly during the OER process,remain to be poorly *** this study,a series of LDH catalysts is investigated through in situ X-ray absorption fine structure analyses and density functional theory(DFT) *** experimental results reveal that the LDH catalyst with equal amounts of Ni and Fe(NF-LDH) exhibits the highest OER activity and catalytic life span when compared with its counterparts having equal amounts of Ni and Co(NC-LDH)and Ni only(Ni-LDH).The NF-LDH shows a markedly enhanced OER kinetics compared to the NC-LDH and the Ni-LDH,as proven by the lower overpotentials of 180,240,and 310 mV,respectively,and the Tafel slopes of 35.1,43.4,and 62.7 mV dec^(-1),*** DFT calculations demonstrate that the lowest overpotential of the NF-LDH is associated with the active sites located at the edge planes of NF-LDH in contrast to those located at the basal planes of Ni-LDH and *** current study pinpoints the active sites on various LDHs and presents strategies for optimizing the OER performance of the LDH catalysts.

关键词： Layered double hydroxides Oxygen evolution reaction In situ X-ray analyses Density functional theory Catalytic active sites

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Surface exsolution and local atomic structure of amorphous CeTiO_x

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Journal of Rare Earths 2019年第2期37卷 160-165页

作者： Seung-hyeon Jo Soonok kim Jiseung Ryu Dae-Seung Cho Bora jeong Heesoo Lee Department of Materials Science and Engineering Pusan National University Department of Naval Architecture & Ocean Engineering Pusan National University Green Materials & Processes Group Ulsan Regional Division Korea Institute of Industrial Technology

We made precipitated nano-ceria(~5 nm) on the surface of the catalyst by heat treatment of Cesupersaturated amorphous CeTiOxto improve the oxygen storage properties of CeO_2. The catalysts were prepared by sol-gel methods and TiO_2 nanoparticles were preferentially generated as a core material to form selective Ce-supersaturated structure on the catalyst surface. Reaction temperature and amount of doping element are optimized to induce selective crystallization of CeO_2. Cee Ce(2 nd shell)bond around 0.38 nm of Ce L3-edge extended X-ray absorption fine structure is reduced and nanostructure of precipitated ceria on the surface is observed by HREM. The catalyst is present as amorphous with precipitated nano-CeO_2 on the surface. The de-NOxefficiency of the catalyst, which has precipitated CeO_2, improves by ~50% owing to the simultaneous reactions of the nano CeO_2 and the amorphous CeTiO_x.

关键词： Ce-Ti oxide Exsolution Amorphous catalyst Local atomic structure De-NO_x efficiency Rare earths

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Endoscopic ultrasound-guided biliary drainage with placement of a fully covered metal stent for malignant biliary obstruction

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World Journal of Gastroenterology 2012年第20期18卷 2526-2532页

作者： Tae hyeon kim Seong Hun kim Hyo jeong Oh Young Woo Sohn Seung Ok Lee Department of Internal Medicine School of MedicineWonkwang UniversityIksanChonbuk 570-749 South Korea Department of Internal Medicine Chonbuk National University Medical School and HospitalJeonjuChonbuk 561-712South Korea Department of Internal Medicine School of MedicineWonkwang UniversitySanbon Gyounggi 570-749South Korea

AIM:To determine the utility of endoscopic ultrasoundguided biliary drainage(EUS-BD)with a fully covered self-expandable metal stent for managing malignant biliary stricture. METHODS:We collected data from 13 patients who presented with malignant biliary obstruction and underwent EUS-BD with a nitinol fully covered selfexpandable metal stent when endoscopic retrograde cholangiopancreatography(ERCP)***-guided choledochoduodenostomy(EUS-CD)and EUS-guided hepaticogastrostomy(EUS-HG)was performed in 9 patients and 4 patients,respectively. RESULTS:The technical and functional success rate was 92.3%(12/13)and 91.7%(11/12),respectively. Using an intrahepatic approach(EUS-HG,n=4),there was mild peritonitis(n=1)and migration of the metal stent to the stomach(n=1).With an extrahepatic approach(EUS-CD,n=10),there was pneumoperitoneum(n=2),migration(n=2),and mild peritonitis (n=1).All patients were managed conservatively with *** follow-up(range,1-12 mo),there was re-intervention(4/13 cases,30.7%)necessitated by stent migration(n=2)and stent occlusion(n=2). CONCLUSION:EUS-BD with a nitinol fully covered self-expandable metal stent may be a feasible and effective treatment option in patients with malignant biliary obstruction when ERCP fails.

关键词： Endoscopic ultrasound-guided Biliary drainage Metal stent Biliary obstruction

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Programmable directional color dynamics using plasmonics

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Microsystems & Nanoengineering 2024年第1期10卷 325-334页

作者： Gyurin kim Doeun kim Soeun Ko Jang-Hwan Han Juhwan kim Joo Hwan Ko Young Min Song hyeon-Ho jeong School of Electrical Engineering and Computer Science Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Department of Semiconductor Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Artificial Intelligence(AI)Graduate School Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual ***,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural ***,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer *** nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission ***,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible ***,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

关键词： directional prevailing exceptional

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Protective Effect of Brassica napus *** against Inflammation Response in RAW 264.7 Cells

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Chinese Journal of Integrative Medicine 2021年第4期27卷 273-279页

作者： Su-hyeon Cho Song Rae kim Myeong Seon jeong Miri Choi SeonJu Park Kil-Nam kim Chuncheon Center Korea Basic Science InstituteChuncheon(24341)Republic of Korea

Objective:To demonstrate the anti-inflammatory activity of Brassica napus ***(BNH)in lipopolysaccharide(LPS)-stimulated RAW 264.7 ***:Composition analysis of BNH was conducted via gas chromatography-mass spectrometry after BNH were *** nitric oxide(NO)production was measured using the Griess *** E2(PGE2)production was evaluated with enzyme-linked immunosorbent *** effects of BNH on LPS-induced pro-inflammatory enzymes including inducible nitric oxide synthase(iNOS)and cyclooxygenase-2(COX-2)were evaluated using Western blot ***,phosphorylation of nuclear factor-kappa B(N F-k B)and nuclear translocation of N F-k B p65 were evaluated with Western blot analysis and immunofluorescence staining,***:Compared with LPS-stimulated cells,BNH markedly decreased the generation of NO and PGE_(2)in LPS-stimulated RAW 264.7 cells(P<0.01 or P<0.05).Moreover,BNH inhibited protein levels of iNOS and COX-2(P<0.01).Phosphorylation of NF-k B and nuclear translocation of NF-k B p65 was significantly inhibited by BNH(P<0.01 or P<0.05).Conclusion:The anti-inflammatory activities of BNH were mediated via blockage of the N F-k B signaling pathways in LPS-stimulated RAW 264.7 cells.

关键词： Brassica napus L. inflammation lipopolysaccharide RAW 264.7 cells hydrosols

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Influence of the molecular structure of metal-phthalocyanine on electrocatalytic reactions

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Science China Materials 2022年第12期65卷 3324-3333页

作者： Da Sol jeong hyeon Suk Shin Jieun Yang Department of Chemistry Ulsan National Institute of Science and Technology(UNIST)50 UNIST-gilUlsan 44919Republic of Korea Department of Chemistry and Research Institute of Basic Sciences Kyung Hee University26 Kyungheedae-roDongdaemun-guSeoul 02447Republic of Korea

The demand for new catalysts for renewable energy production has become *** an alternative to metal catalysts for electrocatalysis to produce energy sources,metal-phthalocyanine(MPc)electrocatalysts have shown *** physicochemical and electrochemical properties depend on the chemical structure of the MPc and the central metal *** reviews of MPcs focused on their electrochemical performance in specific catalytic reactions,such as oxygen reduction reaction and CO_(2)reduction ***,understanding the structure of MPcs in depth is important,since their electrochemical catalytic activity is affected by structural modifications of ***,this minireview focuses on how the molecular structure of MPcs affects electrochemical catalysis.

关键词： metal-phthalocyanine oxygen reduction reaction carbon dioxide reduction reaction hydrogen evolution reaction oxygen evolution reaction electrocatalytic activities

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Unveiling anomalous lattice shrinkage induced by Pi-backbonding in Prussian blue analogues

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Journal of Energy Chemistry 2022年第7期31卷 121-128,I0004页

作者： Ju-hyeon Lee Jin-Gyu Bae hyeon jeong Lee Ji Hoon Lee School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Department of Materials University of OxfordOxford OX13PHUnited Kingdom

Transition-metal(TM)-based Prussian blue and its analogues(TM-PBAs) have attracted considerable attention as cathode materials owing to their versatile ion storage capability with tunable working voltages. TM-PBAs with different crystal structures, morphologies, and TM combinations can exhibit excellent electrochemical properties because of their unique and robust host frameworks with well-defined ionic diffusion channels. Nonetheless, there is still a lack of understanding regarding the performance dependence of TM-PBAs on structural changes during charging/discharging processes. In this study, in situ X-ray diffraction and X-ray absorption fine structure analyses elucidate the TMdependent structural changes in a series of TM-PBAs during the charging and discharging *** the discharging process, the lattice volume of Fe-PBA increased while those of Ni-and Cu-PBAs decreased. This discrepancy is attributed to the extent of size reduction of the cyanometallate complex([Fe(CN)_(6)]) via pi-backbonding from Fe to C due to redox flips of the low-spin Fe^(3+/2+) ion. This study presents a comprehensive understanding of how TM selection affects capacity acquisition and phase transition in TM-PBAs, a promising class of cathode materials.

关键词： Prussian blue analogues X-ray diffraction X-ray absorption fine structure Pi-backdonation Cyanides

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Prognostic role of plasma level of angiopoietin-1,angiopoietin-2,and vascular endothelial growth factor in hepatocellular carcinoma

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World Journal of Gastroenterology 2021年第27期27卷 4453-4467页

作者： Gwang hyeon Choi Eun Sun Jang Jin-Wook kim Sook-Hyang jeong Department of Internal Medicine Seoul National University Bundang HospitalSeoul National University College of MedicineSeongnam 13620South Korea

BACKGROUND Most hepatocellular carcinomas(HCCs)are hypervascular,with characteristic features of hepatic arterial supply to the *** factors involved in tumor angiogenesis include angiopoietin-1(Ang-1),angiopoietin-2(Ang-2),and vascular endothelial growth factor(VEGF).AIM To investigate the profiles of plasma levels of angiogenesis markers in patients with HCC and evaluate their roles in predicting overall survival(OS)and progression-free survival(PFS).METHODS Plasma samples from 240 prospectively enrolled HCC patients in the very early to advanced stages were used to measure the levels of Ang-1,Ang-2,and *** associations with clinical characteristics,OS,and PFS were *** The median plasma levels of Ang-1,Ang-2,and VEGF were 3216 pg/mL,1684 pg/mL,and 26.5 pg/mL,*** plasma level of Ang-2 showed a significant increase from early stage[Barcelona clinic liver cancer(BCLC)A]to intermediate(BCLC B)and advanced stage HCC(BCLC C/D),whereas Ang-1,VEGF,and alpha-fetoprotein(AFP)levels in the plasma did not show any such *** analysis,propensity score-matched analysis,and timedependent receiver operating curve analysis revealed that Ang-2 levels had the highest predictive power for OS and *** Ang-1 nor VEGF was significantly associated with OS or *** neutrophil-to-lymphocyte ratio was an independent factor for OS and *** The plasma levels of Ang-2 correlated with liver function,tumor stage,and tumor invasiveness,showing better performance in predicting OS and PFS than AFP,Ang-1,or VEGF.

关键词： Hepatocellular carcinoma Angiogenesis Biomarker Prognosis Survival

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