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Journal of Materials Science & Technology 2019年第5期35卷 891-901页

作者： Woo Jin Lee Jisoo Kim Hyung Wook park Department of Mechanical Aerospace and Nuclear Engineering Ulsan National Institute of Science and Technology

Large pulsed electron beam(LPEB) irradiation was employed as a surface treatment of magnesium(Mg)alloy AZ31B to enhance its corrosion and wear resistance. Selective evaporation of Mg induced by LPEB irradiation at an energy density of 5J/cm^2 for 40 cycles has led to the formation of an Al-enriched resolidified layer with nano-grained structure consisting of Mg3.1 Al0.9 metastable phase. The formation of such a re-solidified layer after LPEB irradiation has enabled a decrease in corrosion rate of Mg alloy AZ31B in 3.5% NaCl solution. Different equivalent electrical circuit models were proposed to account for the corrosion behavior of untreated Mg alloy AZ31B and those subjected to LPEB irradiation. A decrease in wear depth when compared to that of the untreated alloy suggests an increase in wear resistance of LPEB-irradiated Mg alloy AZ31B. Adhesive wear is the predominant mechanism of untreated Mg alloy AZ31B while abrasive wear mechanism dominates for LPEB-irradiated Mg alloy AZ31B.

关键词： Magnesium alloys Electron beam treatment Corrosion resistance Microstructure Rapid re-solidification Wear resistance

Microstructure and corrosion resistance of a Mg2Sn-dispersed Mg alloy subjected to pulsed electron beam treatment

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Journal of Magnesium and Alloys 2020年第2期8卷 345-351页

作者： Daseul Lee Beomcheol Kim Soo-Min Baek Jisoo Kim Hyung Wook park Jung Gu Lee Sung Soo park School of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea School of Mechanical Aerospace and Nuclear EngineeringUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea

We report that the corrosion resistance of a Mg-Sn-based alloy with MgzSn precipitates can be considerably improved by surface modification using pulsed electron beam treatment.The alloy subjected to a pulse electron beam treatment showed a modified surface layer with a thickness of〜12 μm,appearing more resistant to corrosion attack than the bare surface of the alloy.In 0.6 M NaCl solution,the alloys with and without the surface modification exhibited average corrosion rates of 4.3 and 8.1 mm y^-1,respectively.The improved corrosion resistance was attributed to reduced cathodic activation,resulting from the surficial reduction of relatively noble Mg2Sn precipitates.

关键词： Magnesium alloy Mg2Sn Intermetallic compound Pulsed electron beam treatment Corrosion

Crystal Facet Engineering of TiO_(2) Nanostructures for Enhancing Photoelectrochemical Water Splitting with BiVO_(4) Nanodots

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Nano-Micro Letters 2022年第3期14卷 201-215页

作者： Mi Gyoung Lee Jin wook Yang Hoonkee park Cheon Woo Moon Dinsefa M.Andoshe Jongseong park Chang‑Ki Moon Tae hyung Lee Kyoung Soon Choi Woo Seok Cheon Jang‑Joo Kim Ho Won Jang Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoul 08826Republic of Korea Department of Chemistry and Nanoscience Ewha Womans UniversitySeoul 03693Republic of Korea National Research Facilities and Equipment Center Korea Basic Science InstituteDaejeon 34133Republic of Korea Advanced Institute of Convergence Technology Seoul National UniversitySuwon 16229Republic of Korea

Although bismuth vanadate(BiVO4)has been promising as photoanode material for photoelectrochemical water splitting,its charge recombination issue by short charge diffusion length has led to various studies about heterostructure photoanodes.As a hole blocking layer of BiVO4,titanium dioxide(TiO_(2)) has been considered unsuitable because of its relatively positive valence band edge and low electrical conductivity.Herein,a crystal facet engineering of TiO_(2) nanostructures is proposed to control band structures for the hole blocking layer of BiVO4 nanodots.We design two types of TiO_(2) nanostructures,which are nanorods(NRs)and nanoflowers(NFs)with different(001)and(110)crystal facets,respectively,and fabricate BiVO4/TiO_(2) heterostructure photoanodes.The BiVO4/TiO_(2) NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO_(2) NRs.Transient decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination,which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO_(2) NFs.This work provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes.

关键词： Crystal facet control Bismuth vanadate Titanium dioxide Heterojunction Water splitting

Ultrasonographic identification of lateral femoral cutaneous nerve anatomical variation in persistent meralgia paresthetica:A case report

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World Journal of Clinical Cases 2023年第31期11卷 7699-7705页

作者： Hyeong-Woo park Kyung-Suk Ji Jun-hyung Kim Li-Na Kim Kang-wook Ha Department of Physical Medicine and Rehabilitation Sahmyook Medical CenterSeoul 02500South Korea Department of Obstetrics and Gynecology Sahmyook Medical CenterSeoul 02500South Korea

BACKGROUND Meralgia paresthetica(MP)is an entrapment mononeuropathy of the lateral femoral cutaneous nerve(LFCN).Although structural abnormalities in nerve tissues can be confirmed using ultrasonography,this is not routinely performed.CASE SUMMARY Herein,we present the case of a 52-year-old woman who developed MP after laparoscopic gynecological surgery.The patient was referred to our clinic from an obstetrics and gynecology clinic with symptoms of numbness and a tingling sensation in the left anterolateral thigh,which developed after surgery performed 5 mo earlier.Tests were performed to assess the disease status and determine the underlying causes.Ultrasonographic examination revealed an anatomical variation,where the left LFCN was entrapped within the inguinal ligament.This case suggests that performing ultrasonographic examination before and after surgery in the lithotomy position could help prevent MP.CONCLUSION This case demonstrates the value of ultrasonography in detecting anatomical variation and diagnosing persistent MP.Ultrasonography should be considered an adjunct to electromyography for optimal MP management.Further,this case would help other clinicians determine patient prognosis and decide on targeted treatment strategies.

关键词： Lateral femoral cutaneous nerve Anatomical variation Meralgia paresthetica Lithotomy position Ultrasonography Case report

Advantage of endoscopic mucosal resection with a cap for rectal neuroendocrine tumors

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World Journal of Gastroenterology 2015年第31期21卷 9387-9393页

作者： Su Bum park hyung wook Kim Dae Hwan Kang Cheol Woong Choi Su Jin Kim Hyeong Seok Nam Department of Internal Medicine Pusan National University School of Medicine Research institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital

AIM: To compare the outcomes of endoscopic mucosal resection with a cap(EMR-C) with those of endoscopic submucosal dissection(ESD) for the resection of rectal neuroendocrine tumors.METHODS: One hundred and sixteen lesions in 114 patients with rectal neuroendocrine tumor(NET) resected with EMR-C or ESD were included in the study. This study was performed at Pusan National University Yangsan Hospital between July 2009 and August 2014. We analyzed endoscopic complete resection rate,pathologic complete resection rate,procedure time,and adverse events in the EMR-C(n = 65) and ESD(n = 51) groups. We also performed a subgroup analysis by tumor size.RESULTS: Mean tumor size was 4.62 ± 1.66 mm in the EMR-C group and 7.73 ± 3.14 mm in the ESD group(P < 0.001). Endoscopic complete resection rate was 100% in both groups. Histologic complete resection rate was significantly greater in the EMR-C group(92.3%) than in the ESD group(78.4%)(P = 0.042). Mean procedure time was significantly longer in the ESD group(14.43 ± 7.26 min) than in the EMR-C group(3.83 ± 1.17 min)(P < 0.001). Rates of histologic complete resection without complication were similar for tumor diameter ≤ 5 mm(EMR-C,96%; ESD,100%,P = 0.472) as well as in cases of 5 mm < tumor diameter ≤ 10 mm(EMR-C,80%; ESD,71.0%,P = 0.524).CONCLUSION: EMR-C may be simple,faster,and more effective than ESD in removing rectal NETs and may be preferable for resection of small rectal NETs.

关键词： Neuroendocrine tumor Endoscopic mucosal resection

Double layered self-expanding metal stents for malignant esophageal obstruction, especially across the gastroesophageal junction

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World Journal of Gastroenterology 2012年第28期18卷 3732-3737页

作者： Min Dae Kim Su Bum park Dae Hwan Kang Jae hyung Lee Cheol Woong Choi hyung wook Kim Chung Uk Chung Young Il Jeong Department of Internal Medicine Bongseng Memorial Hospital Busan 601-723 South Korea Department of Internal Medicine Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan 626-770 South Korea

AIM: To evaluate the clinical outcomes of double-layered self-expanding metal stents (SEMS) for treatment of malignant esophageal obstruction according to whether SEMS crosses the gastroesophageal junction (GEJ). METHODS: Forty eight patients who underwent the SEMS insertion for malignant esophageal obstruction were enrolled. Patients were classified as GEJ group (SEMS across GEJ, 18 patients) and non-GEJ group (SEMS above GEJ, 30 patients) according to SEMS position. Double layered (outer uncovered and inner covered stent) esophageal stents were placed. RESULTS: The SEMS insertion and the clinical improvement were achieved in all patients in both groups. Stent malfunction occurred in seven patients in the GEJ group and nine patients in the non-GEJ group. Tumor overgrowth occurred in five and eight patients, respectively, food impaction occurred in one patient in each group, and stent migration occurred in one and no patient, respectively. There were no significant differences between the two groups. Reflux esophagitis occurred more frequently in the GEJ group (eight vs five patients, P = 0.036) and was controlled by proton pump inhibitor. Aspiration pneumonia occurred in zero and five patients, respectively, and tracheoesophageal fistula occurred in zero and two patients, respectively. CONCLUSION: Double-layered SEMS are a feasible and effective treatment when placed across the GEJ for malignant esophageal obstruction. Double-layered SEMS provide acceptable complications, especially migration, although reflux esophagitis is more common in the GEJ group.

关键词：金属支架交界处食管梗阻恶性治疗 SEMS 质子泵抑制剂

Efficacy and safety of limited endoscopic sphincterotomy before self-expandable metal stent insertion for malignant biliary obstruction

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World Journal of Gastroenterology 2017年第9期23卷 1627-1636页

作者： Hyeong Seok Nam Dae Hwan Kang hyung wook Kim Cheol Woong Choi Su Bum park Su Jin Kim Dae Gon Ryu Department of Internal Medicine Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and TechnologyPusan National University Yangsan HospitalYangsan-siGyeongsangnam-do 50612South Korea

AIM To evaluate the safety and efficacy of limited endoscopic sphincterotomy (ES) before placement of selfexpandable metal stent(SEMS).METHODS This was a retrospective analysis of 244 consecutive patients with unresectable malignant biliary obstruction, who underwent placement of SEMSs following limited ES from December 2008 to February 2015. The diagnosis of malignant biliary obstruction and assessment of patient eligibility for the study was established by a combination of clinical findings, laboratory investigations, imaging and pathological results. All patients were monitored in the hospital for at least 24 h following endoscopic retrograde cholangio pancreatography(ERCP). The incidence of immediate or early post-ERCP complications such as post-ERCP pancreatitis(PEP) and bleeding related to limited ES were considered as primary outcomes. Also, characteristics and complications according to the cancer type were classified.RESULTS Among the 244 patients included, the underlying diagnosis was cholangiocarcinoma in 118 patients,pancreatic cancer in 79, and non-pancreatic or nonbiliary malignancies in the remaining 47 patients. Early post-ERCP complications occurred in 9 patients(3.7%), with PEP in 7 patients (2.9%; mild, 6; moderate, 1) and mild bleeding in 2 patients (0.8%). There was no significant association between the incidence of post-ERCP complications and the type of malignancy(cholangiocarcinoma vs pancreatic cancer vs others, P = 0.696) or the type of SEMS used (uncovered vs covered, P = 1.000). Patients who had more than one SEMS placed at the first instance were at a significantly higher risk of post-ERCP complications (one SEMS vs two SEMS, P = 0.031). No other factors were predictive of post-ERCP complications.CONCLUSION Limited ES is feasible and safe, and effectively facilitates the placement of SEMS, without any significant risk of PEP or severe bleeding.

关键词：内视镜的 sphincterotomy 内视镜后退 cholangio pancreatography 复杂并发症胰腺炎流血 Cholestasis 自我可扩充的金属 stent

Is endoscopic ultrasonography essential for endoscopic resection of small rectal neuroendocrine tumors?

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World Journal of Gastroenterology 2017年第11期23卷 2037-2043页

作者： Su Bum park Dong Jun Kim hyung wook Kim Cheol Woong Choi Dae Hwan Kang Su Jin Kim Hyeong Seok Nam Department of Internal Medicine Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and TechnologyPusan National University Yangsan HospitalYangsanGyeongsangnam-do 626-770South Korea

AIM To evaluate the importance of endoscopic ultrasonography(EUS) for small(≤ 10 mm) rectal neuroendocrine tumor(NET) treatment.METHODS Patients in whom rectal NETs were diagnosed by endoscopic resection(ER) at the Pusan National University Yangsan Hospital between 2008 and 2014 were included in this study. A total of 120 small rectal NETs in 118 patients were included in this study. Histologic features and clinical outcomes were analyzed, and the findings of endoscopy, EUS and histology were compared. RESULTS The size measured by endoscopy was not significantly different from that measured by EUS and histology(r = 0.914 and r = 0.727 respectively). Accuracy for the depth of invasion was 92.5% with EUS. No patients showed invasion of the muscularis propria or metastasis to the regional lymph nodes. All rectal NETswere classified as grade 1 and demonstrated an L-cell phenotype. Mean follow-up duration was 407.54 ± 374.16 d. No patients had local or distant metastasis during the follow-up periods. CONCLUSION EUS is not essential for ER in the patient with small rectal NETs because of the prominent morphology and benign behavior.

关键词： Neuroendocrine tumor Small Rectal Endoscopic ultrasonography Histology Endoscopy

Assessment of disease activity by fecal immunochemical test in ulcerative colitis

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World Journal of Gastroenterology 2016年第48期22卷 10617-10624页

作者： Dae Gon Ryu hyung wook Kim Su Bum park Dae Hwan Kang Cheol Woong Choi Su Jin Kim Hyeong Seok Nam Department of Internal Medicine Pusan National University School of Medicine and Research Institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital

AIM To evaluate the efficacy of quantitative fecal immunochemical test(FIT) as biomarker of disease activity in ulcerative colitis(UC).METHODS Between February 2013 and November 2014, a total of 82 FIT results, obtained in conjunction with colonoscopies, were retrospectivelyevaluated for 63 patients with UC. The efficacy of FIT for evaluation of disease activity was compared to colonoscopic findings. Quantitative fecal blood with automated equipment examined from collected feces. Endoscopic disease severity were assessed using the Mayo endoscopic subscore(MES) classification. The extent of disease were classified by proctitis(E1), left sided colitis(E2), and extensive colitis(E3). Clinical activity were subgrouped by remission or active.RESULTS All of 21 patients with MES 0 had negative FIT( 134.89 ng/m L. The sensitivity, specificity, positive predictive value(PPV), negative predictive value(NPV) and accuracy of negative FIT about mucosal healing were 73.33%, 81.82%, 91.49%, 51.43% and 73.17%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of predictive value of positive FIT(cutoff value > 100 ng/mL) about active disease status were 45.45%, 93.33%, 71.43%, 82.35%and 26.83%, respectively. Among patients with clinical remission, FIT was negative in 31(81.6%) of 38 cases, with a mean fecal hemoglobin concentration of 6.12 ng/mL(range, negative to 80.9 ng/mL) for this group of patients. Among patients with clinical active disease, FIT was negative in 16(36.4%) out of 44 cases, with a mean fecal hemoglobin concentration > 167.4 ng/mL for this group of patients. FIT was positively correlated with endoscopic activity(r = 0.626, P < 0.01) and clinical activity(r = 0.496, P < 0.01). But, FIT did not correlate with the extent of disease(r =-0.047, P = 0.676)CONCLUSION Quantitative FIT can be a non-invasive and effective biomarker for evaluation of clinical and endoscopic activity in UC, but not predict the extent of disease.

关键词： Ulcerative colitis Fecal immunochemical test Mayo endoscopic subscore Biomarker Disease activity

The association of benign prostatic hyperplasia with lower urinary tract stones in adult men: A retrospective multicenter study

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Asian Journal of Urology 2018年第2期5卷 118-121页

作者： Jae Hung Jung Jinsung park Won Tae Kim Hong wook Kim hyung Joon Kim Sungwoo Hong Hee Jo Yang Hong Chung Department of Urology Yonsei UniversityWonju College of MedicineWonjuKorea Department of Urology Eulji UniversityCollege of MedicineDaejeonKorea Department of Urology Chungbuk National UniversityCollege of MedicineCheongjuKorea Department of Urology Konyang UniversityCollege of MedicineDaejeonKorea Department of Urology Dankook UniversityCollege of MedicineCheonanKorea Department of Urology Cheonan HospitalSoonchunhyang UniversityCollege of MedicineCheonanKorea Department of Urology Konkuk UniversitySchool of MedicineChungjuKorea

Objective:To examine the relationship between benign prostatic hyperplasia(BPH)and the presence of lower urinary tract stones.Methods:We retrospectively reviewed the records of men with lower urinary tract stones who presented to three clinical centers in Korea over a 4-year period.We divided the patients into two groups based on the location of urinary stones:Group 1(bladder calculi)and Group 2(urethral calculi).We compared the characteristics of both groups and performed univariate and multivariate analyses with a logistic regression model to investigate the relationship between BPH and lower urinary tract stones.Results:Of 221 patients,194(87.8%)had bladder calculi and 27(12.2%)had urethral calculi.The mean age of Group 1 was higher than that of Group 2(68.9612.11 years vs.55.7414.20 years,p<0.001).The mean prostate volume of Group 1 was higher than that of Group 2(44.4727.14 mL vs.24.706.41 mL,respectively,p<0.001).Multivariate logistic regression showed that age(OR Z 1.075,95%CI:1.023e1.129)and prostate volume(OR Z 1.069,95%CI:1.017e1.123)were independently associated with increased risk for bladder calculi.Upper urinary tract stones and/or hydronephrosis conferred a 3-fold risk for urethral calculi(OR Z 3.468,95%CI:1.093e10.999).Conclusion:Age and prostate volume are independent risk factors for bladder calculi.In addition,men with upper urinary tract disease are at greater risk for urethral calculi,which may migrate from the upper urinary tract rather than from the bladder.

关键词： Prostatic hyperplasia Urethra Urinary bladder Urolithiasis Lower urinary tract stones