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Journal of Magnesium and Alloys 2022年第6期10卷 1672-1679页

作者： Joo-Hee Kang Jiwon Park Kyung Song chang-seok oh Oleg Shchyglo Ingo Steinbach Korea Institute of Materials Science Changwon 51508Republic of Korea Interdisciplinary Centre for Advanced Materials Simulation Ruhr-University Bochum44801 BochumGermany

In this study the partially divorced eutectic microstructure ofα-Mg andβ-Mg17Al12was investigated by electron backscatter diffraction,transmission electron microscopy,and phase-field modeling in hypoeutectic Mg-Al *** orientation relationships between the individual eutecticαgrains,eutecticβphase,and primaryαgrains were *** the amount of eutectic morphology is primarily determined by the Al content,the in-depth microstructure analyses and the phase-field simulation suggest non-interactive nucleation and growth of eutecticαphase in theβphase grown on the interdendritic primaryα***,phase-field simulations showed a preferred nucleation sequence where theβphase nucleates first and subsequently triggers the nucleation of eutecticαphase at the movingβphase solidification front,which supports the microstructural analysis results.

关键词： Mg-Al alloy Partially divorced eutectic Solidification Electron backscatter diffraction Phase-Field modeling

Decomposition behavior of yttria-stabilized zirconia and its effect on directed energy deposited Ti-based composite material

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Journal of Materials Science & Technology 2022年第17期112卷 138-150页

作者： Gwanghyo Choi Won seok Choi Yoon Sun Lee Dahye Kim Ji Hyun Sung Seungjun An chang-seok oh Amine Hattal Madjid Djemai Brigitte Bacroix Guy Dirras Pyuck-Pa Choi Department of Materials Science and Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea 3D Additive Manufacturing Application Tech.Center Korea Institute of Industrial TechnologyDaegu 42994Republic of Korea InssTek Co. Daejeon 04763Republic of Korea Korea Institute of Materials Science 797 ChangwondaeroChangwon 51508Republic of Korea UniversitéSorbonne Paris Nord Laboratoire des Sciences des Procédés et des MatériauxLSPMCNRSUPR 3407F-93430VilletaneuseFrance Z3Dlab Parc Technologique26 Rue des SablonsMontmagny 95360France CNRS UPR3407Laboratoire des Sciences des Procédés et des MatériauxLSPMUniversitéSorbonne Paris NordF-93430VilletaneuseFrance

We report on the microstructure and the strengthening mechanisms of additively manufactured parts fabricated by directed energy deposition of Ti-6Al-4V(Ti64)powders blended with yttria-stabilized zirconia(YSZ)*** specimens showed refined microstructures as compared to bare as-deposited Ti64,where theαand columnar priorβgrain sizes decreased with increasing YSZ *** YSZ nanoparticles decomposed during the deposition process and led to the formation of yttrium oxide and some excess oxygen in the Ti64 *** decrease in the sizes of the priorβgrains could be attributed to the increasing amount of dissolved oxygen and yttrium,which promoted constitutional ***,the reduction in the size of theαgrains could be ascribed to a shift of the onset of theβ→α+βtransformation to a higher temperature and shorter time with increasing concentration of dissolved ***,the contributions of the underlying strengthening mechanisms for the as-deposited specimens were quantitatively determined.

关键词： Additive manufacturing Directed energy deposition Metal matrix composites Titanium alloys Yttrium-stabilized zirconia

Long-term observation of the mineral trioxide aggregate extrusion into the periapical lesion:a case series

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International Journal of Oral Science 2013年第1期5卷 54-57页

作者： seok-Woo chang Tae-seok oh WooCheol Lee Gary Shun-Pan Cheung Hyeon-Cheol Kim Department of Conservative Dentistry School of DentistryKyung Hee University Department of Conservative Dentistry The Institute of Oral Health ScienceSamsung Medical CenterSungkyunkwan University School of Medicine Department of Conservative Dentistry School of DentistryDental Research InstituteSeoul National University Area of Endodontics Faculty of Dentistrythe University of Hong Kong Department of Conservative Dentistry School of DentistryPusan National UniversityDental Research Institute

One-step apexification using mineral trioxide aggregate(MTA) has been reported as an alternative treatment modality with more benefits than the use of long-term calcium hydroxide for teeth with open ***,orthograde placement of MTA is a challenging procedure in terms of length *** case series describes the sequence of events following apical extrusion of MTA into the periapical area during a one-step apexification procedure for maxillary central incisor with an infected immature *** long-term observation revealed complete resolution of the periapical radiolucent lesion around the extruded *** cases revealed that direct contact with MTA had no negative effects on healing of the periapical ***,intentional MTA overfilling into the periapical lesion is not to be recommended.

关键词： extrusion immature apex mineral trioxide aggregate one-step apexification open apex periapical healing

Recurrent massive bleeding due to dissecting intramural hematoma of the esophagus: Treatment with therapeutic angiography

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World Journal of Gastroenterology 2009年第41期15卷 5232-5235页

作者： Jaejun Shim Jae Young Jang Young Hwangbo seok Ho Dong Joo Hyeong oh Hyo Jong Kim Byung-Ho Kim Young Woon chang Rin chang Department of Internal Medicine Kyung Hee University School of Medicine Hoegi-dong 1 Dongdaemoongu Seoul 130-702 South Korea Department of Diagnostic Radiology Kyung Hee University School of Medicine Hoegi-dong 1 Dongdaemoon-gu Seoul 130-702 South Korea

Spontaneous or traumatic intramural bleeding of the esophagus, which is often associated with overlying mucosal dissection, constitutes a rare spectrum of esophageal injury called dissecting intramural hematoma of the esophagus (DIHE). Chest pain, swallowing diffi culty, and minor hematemesis are common, which resolve spontaneously in most cases. This case report describes a patient with spontaneous DIHE with recurrent massive bleeding which required critical management and highlights a potential role for therapeutic angiography as an alternative to surgery.

关键词： Esophagus Intramural hematoma Therapeutic angiography

Application of artificial intelligence in gastroenterology

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World Journal of Gastroenterology 2019年第14期25卷 1666-1683页

作者： Young Joo Yang chang seok Bang Department of Internal Medicine Hallym University College of Medicine

Artificial intelligence(AI) using deep-learning(DL) has emerged as a breakthrough computer technology. By the era of big data, the accumulation of an enormous number of digital images and medical records drove the need for the utilization of AI to efficiently deal with these data, which have become fundamental resources for a machine to learn by itself. Among several DL models, the convolutional neural network showed outstanding performance in image analysis. In the field of gastroenterology, physicians handle large amounts of clinical data and various kinds of image devices such as endoscopy and ultrasound. AI has been applied in gastroenterology in terms of diagnosis,prognosis, and image analysis. However, potential inherent selection bias cannot be excluded in the form of retrospective study. Because overfitting and spectrum bias(class imbalance) have the possibility of overestimating the accuracy,external validation using unused datasets for model development, collected in a way that minimizes the spectrum bias, is mandatory. For robust verification,prospective studies with adequate inclusion/exclusion criteria, which represent the target populations, are needed. DL has its own lack of *** interpretability is important in that it can provide safety measures, help to detect bias, and create social acceptance, further investigations should be performed.

关键词： Artificial intelligence Convolutional neural network Deep-learning Computer-assisted Gastroenterology Endoscopy

Attempts to enhance the eradication rate of helicobacter pylori infection

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World Journal of Gastroenterology 2014年第18期20卷 5252-5262页

作者： chang seok Bang Gwang Ho Baik Department of Internal Medicine Hallym University College of MedicineChuncheon 200-704South Korea

Increasing rates of antimicrobial resistance to clarithromycin and metronidazole present challenges in maintaining optimal eradication *** of local antibiotic resistance and consumption pattern is important in selecting a reliable *** addition,adverse effect profiles of therapeutic regimens are important and must be addressed to enhance compliance *** methods of enhancing the eradication rates of Helicobacter pylori(***)have been investigated,including changing combinations or durations of established drugs,adding adjuvant drugs,or development of new molecules or ***-containing quadruple,sequential,concomitant,and levofloxacin-based triple therapies are replacing the long-standing standard of the triple *** the encouraging results of these regimens,individualized approaches like treatment after antibiotics resistance test or CYP2C19genotyping would be the mainstream of future *** scientific,economic,and technical problems make these advance therapies unfit for widespread use,future development for *** therapy should be directed to overcome individualized antibiotic *** various novel regimens and additive agents have indicated favorable outcomes,more studies or validations are needed to become a mainstream *** therapy.

关键词： Helicobacter pylori Antimicrobial drug resistance Clarithromycin Metronidazole Microbial sensitivity tests

Solvent extraction and stripping of lithium ion from aqueous solution and its application to seawater

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Rare Metals 2016年第12期35卷 948-953页

作者： Gregorius Rionugroho Harvianto seok-Hyeon Kim chang-Sik Ju Department of Chemical Engineering Pukyong National University

For the development of lithium ion recovery process from seawater, a series of experimental researches were performed. Solvent extraction of lithium ion from aqueous solution using kerosene as solvent was proposed. Lithium ion is effectively extracted by thenoyltrifluoroace- tone-trioctylphosphine oxide （TTA-TOPO） in kerosene within 80 min. Extraction efficiency is severely influenced by stoichiometric parameters. Among the stoichiometric parameters, volume ratio of aqueous （A） to extraction （E） solution is the most influential parameter. After extrac- tion, lithium ion could be easily stripped from the extraction solution by acidic solutions. Stripping efficiency decreases with pH of acidic solutions, and the kind of acid does not affect the stripping efficiency. Extraction efficiency main- tains at more than 93 % even when the extraction solution is recycled three times. 65 % of lithium ion can be extracted from seawater by this solvent extraction process when magnesium ion is precipitated by NHaoh prior to solvent extraction process. Other metallic ions in seawater decrease the extraction efficiency of lithium ion.

关键词： Lithium Thenoyltrifluoroacetone Trioctylphosphine oxide Solvent extraction Stripping Recycling

Extensive frontal focused ultrasound Check for updates mediated blood-brain barrier opening for the treatment of Alzheimer's disease:a proof-of-concept study

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Translational Neurodegeneration 2021年第4期10卷 573-583页

作者： So Hee Park Kyoungwon Baik Seun Jeon Won seok chang Byoung seok Ye Jin Woo chang Brain Research Institute Department of NeurosurgeryYonsei University College of MedicineSeoulKorea Department of Neurology Yonsei University College of MedicineSeoulKorea

Background:Focused ultrasound(FUS)-mediated blood-brain barrier(BBB)opening has shown efficacy in removal of amyloid plaque and improvement of cognitive functions in preclinical studies,but this is rarely reported in clinical *** study was conducted to evaluate the safety,feasibility and potential benefits of repeated extensive BBB ***:In this open-label,prospective study,six patients with Alzheimer's disease(AD)were enrolled at Severance Hospital in Korea between August 2020 and September *** of them completed the ***-mediated BBB opening,targeting the bilateral frontal lobe regions over 20 cm^(3),was performed twice at three-month *** resonance imaging,^(18)F-Florbetaben(FBB)positron emission tomography,Caregiver-Administered Neuropsychiatric Inventory(CGA-NPI)and comprehensive neuropsychological tests were performed before and after the ***:FUS targeted a mean volume of 21.1±2.7 cm^(3)and BBB opening was confirmed at 95.7%±9.4%of the targeted *** frontal-to-other cortical region FBB standardized uptake value ratio at 3 months after the procedure showed a slight decrease,which was statistically significant,compared to the pre-procedure value(-1.6%,0.986 vs 1.002,P=0.043).The CGA-NPI score at 2 weeks after the second procedure significantly decreased compared to baseline(2.2±3.0 vs 8.6±6.0,P=0.042),but recovered after 3 months(5.2±5.8 vs 8.6±6.0,P=0.89).No adverse effects were ***:The repeated and extensive BBB opening in the frontal lobe is safe and feasible for patients with *** addition,the BBB opening is potentially beneficial for amyloid removal in AD patients.

关键词： Alzheimer disease Focused ultrasound Blood-brain barrier Amyloid beta-peptides

Methodology for predicting the life of plasma-sprayed thermal barrier coating system considering oxidation-induced damage

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Journal of Materials Science & Technology 2022年第10期105卷 45-56页

作者： Keekeun Kim Damhyun Kim Kibum Park Junghan Yun chang-Sung seok School of Mechanical Engineering Sungkyunkwan UniversitySuwonGyeonggi 440-746Korea

The lifespan of plasma-sprayed thermal barrier coating(TBC)systems is difficult to predict owing to the variety of microstructures and deterioration *** this study,we developed a novel TBC damage model to reflect deterioration histories;thus,it can be applied to various *** to TBCs is classifed into oxidation and mechanical damage;therefore,a detailed deterioration history can be *** addition,by introducing a virtual S–N diagram,a life prediction model that can be applied to TBCs with various microstructures was *** used the proposed damage and life prediction models in isothermal aging and thermal cycle tests with different aging *** predicted lifespan of TBCs by using the proposed models was within 95%of the results obtained by performing actual tests in the temperature range of 1150–1350℃.

关键词： Thermal barrier coatings Damage model Temperature history Thermal fatigue Life prediction model

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation: a scanning electron microscopy study

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International Journal of Oral Science 2014年第4期6卷 227-232页

作者： Jun Sang Yoo seok-Woo chang So Ram oh Hiran Perinpanayagam Sang-Min Lim Yeon-Jee Yoo Yeo-Rok oh Sang-Bin Woo Seung-Hyun Han Qiang Zhu Kee-Yeon Kum Department of Dentistry U Dental Hospital Department of Conservative Dentistry School of Dentistry Kyung Hee University Department of Conservative Dentistry Dental Research Institute Seoul National University Dental Hospital Seoul National University School of Dentistry Division of Restorative Dentistry Schulich School of Medicine & Dentistry University of Western Ontario Department of Conservative Dentistry Jukjeon Dental Hospital College of Dentistry Dankook University Department of Oral Microbiology & Immunology Dental Research Institute and BK21 Program Seoul National University School of Dentistry Division of Endodontology Department of Oral Health and Diagnostic Sciences School of Dental Medicine University of Connecticut Health Center

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.

关键词： bacterial entombment intratubular mineralization orthograde canal obturation scanning electron microscopy tag-like structure