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Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon Yun Boseok Seong Junseok Kim sun Hee choi Ho-Il Ji Sihyuk choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF < Nd BSCF < Gd BSCF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBSCF cathodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

Clinical characteristics of incidental or unsuspected gallbladder cancers diagnosed during or after cholecystectomy: A systematic review and meta-analysis

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World Journal of Gastroenterology 2015年第4期21卷 1315-1323页

作者： Kui sun choi Sae Byeol choi Pyoungjae Park Wan Bae Kim Sang Yong choi Department of Surgery Korea University College of MedicineSeoul 152-703South Korea

AIM: To perform a systematic review of incidental or unsuspected gallbladder(GB) cancer diagnosed during or after cholecystectomy. METHODS: Data in Pub Med, EMBASE, and CochraneLibrary were reviewed and 26 publications were included in the meta-analysis. The inclusion criterion for incidental GB cancer was GB cancer diagnosed during or after cholecystectomy that was not suspected at a preoperative stage. Pooled proportions of the incidence, distribution of T stage, and revisional surgery of incidental GB cancer were ***: The final pooled population comprised 2145 patients with incidental GB cancers. Incidental GB cancers were found in 0.7% of cholecystectomies p e r f o r m e d f o r b e n i g n g a l l b l a d d e r d i s e a s e s o n preoperative diagnosis(95%CI: 0.004-0.012). Nearly 50% of the incidental GB cancers were stage T2 with a pooled proportion of 47.0%(95%CI: 0.421-0.519). T1 and T3 GB cancers were found at a similar frequency, with pooled proportions of 23.0%(95%CI: 0.178-0.291) and 25.1%(95%CI: 0.195-0.317), respectively. The pooled proportion that completed revisional surgery for curative intent was 40.9%(95%CI: 0.329-0.494). The proportion of patients with unresectable disease upon revisional surgery was 23.0%(95%CI: 0.177-0.294). CONCLUSION: A large proportion of incidental GB cancers were T2 and T3 lesions. Revisional surgery for radical cholecystectomy is warranted in T2 and more advanced cancers.

关键词： Gallbladder cancer Laparoscopic surgery Cholecyste

Extracorporeal membrane oxygenation for lung cancer-related life-threatening hypoxia:A case report

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World Journal of Clinical Cases 2022年第25期10卷 8974-8979页

作者： Seung Soo Yoo Shin Yup Lee sun Ha choi Department of Internal Medicine Kyungpook National UniversityDaegu 41404South Korea Lung Cancer Center Kyungpook National University Chilgok HospitalDaegu 41404South Korea

BACKGROUND Life-threatening hypoxia can occur in patients with lung cancer due to bronchial *** membrane oxygenation(ECMO)can be used as a bridge therapy for patients with severe hypoxia not relieved by conventional mechanical ***,the usefulness of chemotherapy in patients with lung cancer receiving ECMO therapy is not well *** SUMMARY A 53-year-old man visited the emergency room with worsening dyspnea for 1 mo.A series of imaging and diagnostic tests were performed,and stageⅢB(cT4N2M0)lung cancer was eventually *** hospital day 3,he experienced dyspnea and hypoxia that was not relieved with oxygen support via a high-flow nasal *** was initiated because his respiratory condition did not improve even with mechanical *** patient then underwent gemcitabine/cisplatin chemotherapy without dose reduction while on *** two cycles of chemotherapy,there was a decrease in the size of the primary tumor in the right main *** the completion of concurrent chemoradiotherapy,a computed tomography scan revealed further improvement in the right main bronchus *** months after a lung cancer diagnosis,the patient did well without any *** ECMO is a potential bridge therapy for respiratory failure in patients with central airway obstruction secondary to lung cancer.

关键词： Extracorporeal membrane oxygen Lung cancer Hypoxia Respiratory failure Chemoradiotherapy Case report

Injection molding of micro patterned PMMA plate

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 148-152页

作者： Yeong-Eun YOO Tae-Hoon KIM Tae-Jin JE Doo-sun choi Chang-Wan KIM sun-Kyung KIM Department of Nanomanufacturing Technology KIMM 171 Jang-dong Yusung-gu Daejeon 305-343 Korea Department of Product Design and Manufacturing Seoul National University of Technology

A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 minx213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 ram. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate （PMMA） was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

关键词： micro prism pattern injection molding replication pressure profile temperature profile

Congenital stapes suprastructure fixation presenting with fluctuating auditory symptoms:A case report

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World Journal of Clinical Cases 2023年第1期11卷 249-254页

作者： sun choi Seok Hyun Park Ji Su Kim Jiwon Chang Department of Otolaryngology-Head and Neck Surgery Kangnam Sacred Heart HospitalHallym University College of MedicineSeoul 07441South Korea

BACKGROUND Stapes ankylosis is a rare cause of conductive hearing loss,and stapes suprastructure fixation is extremely rare with fewer than 30 reported *** usually visit the clinic with non-progressive conductive hearing loss that typically began in the early years of *** SUMMARY Herein,we report a case of a 37-year-old female with an isolated stapedial suprastructure *** patient presented with unusual fluctuating auditory symptoms of tinnitus,ear fullness and mixed hearing ***-operative temporal bone computed tomography findings and operative findings revealed an isolated stapedial suprastructure fixation with monopod stapes caused by elongated pyramidal *** hearing threshold recovered completely,and fluctuating auditory symptoms disappeared after the *** This is the first report of stapedial suprastructure fixation with fluctuating auditory *** results are expected with surgical treatment.

关键词： Isolated stapes ankylosis Stapes suprastructure fixation Elongated pyramidal eminence Stapes monopod Fluctuating auditory symptoms Exploratory tympanotomy Case report

COVID-19 Stay-At-Home Orders and Older Adults’ Cognitive Health — United States, June 2018–February 2022

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China CDC weekly 2022年第45期4卷 1002-1006,I0003页

作者： Nam sun choi Tianzi Li Jingxiang Pan Selena Yue Jing Li Department of Population Health Sciences Weill Cornell Medical CollegeCornell UniversityNew YorkNYU.S. The Comparative Health Outcomes Policy and Economics(CHOICE)InstituteSchool of PharmacyUniversity of WashingtonSeattleWAU.S.

What is already known about this topic?Lack of social activities is known to negatively impact cognitive functioning and increase risk of cognitive impairment,including dementia,among older *** is added by this report?Coronavirus disease 2019(COVID-19)stay-at-home orders implemented in the *** during the pandemic were not found to negatively affect cognitive functioning of older *** are the implications for public health practice?There may have been no severe,unintended consequences of the COVID-19 stay-at-home orders in terms of their impact on cognitive functioning and risk of dementia among older adults,lending further support to use of such orders.

关键词： impairment consequences COV

Gradient Si-and Ti-doped Fe_(2)O_(3) hierarchical homojunction photoanode for efficient solar water splitting:Effect of facile microwave-assisted growth of Si-FeOOH on Ti-FeOOH nanocorals

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Journal of Energy Chemistry 2023年第2期77卷 27-37,I0002页

作者： Tae Sik Koh Periyasamy Anushkkaran Weon-Sik Chae Hyun Hwi Lee sun Hee choi Jum Suk Jang Division of Biotechnology College of Environmental and Bioresource SciencesJeonbuk National UniversityIksan 54596Republic of Korea Daegu Center Korea Basic Science InstituteDaegu 41566Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in *** the present work,we designed a gradient Si-and Ti-doped Fe_(2)O_(3) homojunction photoanode to improve the photoelectrochemical(PEC)performance of a Ti-doped Fe_(2)O_(3) ***-FeOOH nanocorals were synthesized using a hydrothermal process,and Si-FeOOH was grown on Ti-FeOOH nanocorals using a rapid and facile microwaveassisted(MW)*** varying the MW irradiation time,the thickness of the Si/Ti:Fe_(2)O_(3) photoanode was adjusted and an optimized 3-Si/Ti:Fe_(2)O_(3) photoelectrode was achieved with a significantly enhanced photocurrent density(1.37 mA cm^(-2) at 1.23 V ***)and a cathodic shift of the onset potential(150 mV)compared with that of bare Ti-Fe_(2)O_(3).This enhanced PEC performance can be ascribed to homojunction formation and Si gradient *** Si dopant increased the donor concentration and the formation of a homojunction improved the intrinsic built-in electric field,thereby promoting charge separation and charge ***,the as-formed homojunction passivated the surfacetrapping states,consequently improving the charge transfer efficiency(60%at 1.23 VRHE)at the photoanode/electrolyte *** findings could pave the way for the microwave-assisted fabrication of diverse efficient homojunction photoanodes for PEC water splitting applications.

关键词： Homojunction Microwave-assisted Hematite Gradient doping PEC water splitting

Fabrication of curved micro structures on photoresist layer

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 100-103页

作者： Jae sung YOON Tae-Jin JE Doo-sun choi sung Hwan CHANG Kyung-Hyun WHANG Nano Mechanical Systems Research Division Korea Institute of Machinery and Materials (KIMM) Daejeon 305-343 Korea

A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can he made on the micro channels. The micro channels were made on the silicon suhstrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns.

关键词： micro pattern liquid layer MEMS micro channel silicon substrate

Identification of Aristolactam Derivatives That Act as Inhibitors of Human Immunodeficiency Virus Type 1 Infection and Replication by Targeting Tat-Mediated Viral Transcription

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Virologica Sinica 2021年第2期36卷 254-263页

作者： Young Hyun Shin Chul Min Park Hong Gi Kim Dong-Eun Kim Min Suk choi Jeong-ah Kim Byeong-sun choi Cheol-Hee Yoon Division of Viral Disease Research Center for Infectious Disease ResearchKorea National Institute of HealthHeungdeok-guCheongju-siShungbuk 28159Republic of Korea Center for Convergent Research of Emerging Virus Infection Korea Research Institute of Chemical TechnologyYuseong-guDaejeon 34114Republic of Korea

Despite the success of antiretroviral therapy(ART),efforts to develop new classes of antiviral agents have been hampered by the emergence of drug ***-indole-bearing aristolactams are compounds that have been isolated from various plants species and which show several clinically relevant effects,including anti-inflammatory,antiplatelet,and antimycobacterial ***,the effect of these compounds on human immunodeficiency virus type 1(HIV-1)infection has not yet been *** this study,we discovered an aristolactam derivative bearing dibenzo[cd,f]indol-4(5 H)-one that had a potent anti-HIV-1 effect.A structure-activity relationship(SAR)study using nine synthetic derivatives of aristolactam identified the differing effects of residue substitutions on the inhibition of HIV-1 infection and cell *** the compounds tested,1,2,8,9-tetramethoxy-5-(2-(piperidin-1-yl)ethyl)-dibenzo[cd,f]indol-4(5 H)-one(Compound 2)exhibited the most potent activity by inhibiting HIV-1 infection with a half-maximal inhibitory concentration(IC50)of 1.03 lmol/L and a half-maximal cytotoxic concentration(CC50)of 16.91 lmol/L(selectivity index,16.45).The inhibitory effect of the compounds on HIV-1 infection was linked to inhibition of the viral replication ***-of-action studies showed that the aristolactam derivatives did not affect reverse transcription or integration;instead,they specifically inhibited Tat-mediated viral *** together,these findings show that several aristolactam derivatives impaired HIV-1 infection by inhibiting the activity of Tat-mediated viral transcription,and suggest that these derivatives could be antiviral drug candidates.

关键词： Human immunodeficiency virus type 1(HIV-1) Aristolactam Antiviral activity HIV-1 transcription