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Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection

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International Journal of Oral Science 2013年第1期5卷 26-31页

作者： Hyun-Shik Kim seok woo chang Seung-Ho Baek Seung Hyun Han Yoon Lee Qiang Zhu Kee-Yeon Kum Department of Conservative Dentistry Dental Research Institute and BK21 ProgramSeoul National University Dental HospitalSeoul National University School of Dentistry Department of Conservative Dentistry School of DentistryKyung Hee University Department of Oral Microbiology and Immunology Dental Research Institute and BK21 ProgramSeoul National University Dental HospitalSeoul National University School of Dentistry Department of Dentistry Wonju College of Medicine Yonsei University Division of Endodontology School of Dental MedicineUniversity of Connecticut Health Center

A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than *** aim of this study was to compare the antimicrobial activity of 1%alexidine with that of 2%chlorhexidine using Enterococcus faecalis-infected dentin *** bovine dentin blocks were prepared and randomly divided into six groups of 10 *** was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2%chlorhexidine or 1%alexidine solutions for 5 and 10 min,*** saline was used as a *** antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron *** fewer bacteria were observed in the 2%chlorhexidine-or 1%alexidine-soaked groups than in the control group(P0.05).Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine *** conclusion,10-min soaking with 1%alexidine or 2%chlorhexidine can be effective against *** infection.

关键词： alexidine antibacterial effect chlorhexidine Enterococcus faecalis Luppens apparatus root canal soaking scanning electron microscope

Comparison of the rheological properties of four root canal sealers

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International Journal of Oral Science 2015年第1期7卷 56-61页

作者： seok woo chang Young-Kyu Lee Qiang Zhu Won Jun Shon woo Cheol Lee Kee Yeon Kum Seung Ho Baek In Bog Lee Bum-Soon Lim Kwang Shik Bae Department of Conservative Dentistry School of Dentistry Kyung Hee University National Instrumentation Center for Environmental Management Seoul National University Department of Endodontology School of Dental Medicine University of Connecticut Health Center Department of Conservative Dentistry Dental Research Institute School of Dentistry Seoul National University Dental Hospital Seoul National University Dental Research Institute and Department of Dental Biomaterials School of Dentistry Seoul National University

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method （ISO 6876）, and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer （Capseal） and three commercial root canal sealers （AH Plus, Sealapex and Pulp Canal Sealer EWT） were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method （n= 5） and their viscosities were measured using a strain-controlled rheometer （n=5）. The correlation between these two values was statistically analysed using Spearman＇s correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated （p= -0.8618）. The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order： AH Plus〈Sealapex〈Capseal （P〈0.05）. All of the tested root canal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers.

关键词： Capseal rheological property root canal sealer strain-controlled rheometer

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

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

Characteristic evaluation of Al_2O_3/CNTs hybrid materials for micro-electrical discharge machining

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 28-32页

作者： Hyun-seok TAK chang-Seung HA Ho-Jun LEE Hyung-woo LEE Young-Keun JEONG Myung-chang KANG National Core Research Center for Hybrid Materials Solution Pusan National University Department of Electrical Engineering Pusan National University

The characteristic evaluation of aluminum oxide （A1203）/carbon nanotubes （CNTs） hybrid composites for micro-electrical discharge machining （EDM） was described. Alumina matrix composites reinforced with CNTs were fabricated by a catalytic chemical vapor deposition method. A1203 composites with different CNT concentrations were synthesized. The electrical characteristic of A1203/CNTs composites was examined. These composites were machined by the EDM process according to the various EDM parameters, and the characteristics of machining were analyzed using field emission scanning electron microscope （FESEM）. The electrical conductivity has a increasing tendency as the CNTs content is increased and has a critical point at 5% A1203 （volume fraction）. In the machining accuracy, many tangles of CNT in A1203/CNTs composites cause violent spark. Thus, it causes the poor dimensional accuracy and circularity. The results show that conductivity of the materials and homogeneous distribution of CNTs in the matrix are important factors for micro-EDM of A1203/CNTs hybrid composites.

关键词： A1203/CNTs hybrid materials micro-electrical discharge machining micro-hole electrical conductivity

Suggestion of advanced regression model on friction angle of fault gouge in South Korea

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1368-1379页

作者： Seong-woo Moon Hyun-seok Yun Yong-seok Seo Department of Earth and Environmental Sciences Chungbuk National University1 Chungdae-roCheongju-siChungcheongbuk-do28644South Korea

Although friction characteristics of fault gouge are important to understand reactivation of fault,behavior of earthquake,and mechanism of slope failure,analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low ***,to improve the accuracy of analysis results,we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors,and then we deduced advanced regression model with the highest coefficient of determination(R^(2)) via multiple regression *** most coefficients of determination in simple regression analysis are below0.3-0.4,coefficient of determination in multiple regression analysis is remarkably large as 0.657.

关键词： Fault gouge Friction angle Simple regression analysis Structural equation model analysis Multiple regression analysis

Preoperative defining system for pancreatic head cancer considering surgical resection

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World Journal of Gastroenterology 2016年第26期22卷 6076-6082页

作者： seok Jeong Yang Ho Kyoung Hwang chang Moo Kang woo Jung Lee Department of Surgery Ulsan University Hospital University of Ulsan College of Medicine Department of Hepatobiliary and Pancreatic Surgery Yonsei University College of Medicine Pancreaticobiliary Cancer Clinic Yonsei Cancer Center Institute of Gastroenterology Yonsei Severance Hospital

AIM: To provide appropriate treatment, it is crucial to share the clinical status of pancreas head cancer among multidisciplinary treatment ***: A retrospective analysis of the medical records of 113 patients who underwent surgery for pancreas head cancer from January 2008 to December 2012 was performed. We developed preoperative defining system of pancreatic head cancer by describing “resectability - tumor location - vascular relationship - adjacent organ involvement - preoperative CA19-9 (initial bilirubin level) - vascular anomaly”. The oncologic correlations with this reporting system were ***: Among 113 patients, there were 75 patients (66.4%) with resectable, 34 patients (30.1%) with borderline resectable, and 4 patients (3.5%) with locally advanced pancreatic cancer. Mean disease-free survival was 24.8 mo (95%CI: 19.6-30.1) with a 5-year disease-free survival rate of 13.5%. Pretreatment tumor size ≥ 2.4 cm [Exp(B) = 3.608, 95%CI: 1.512-8.609, P = 0.044] and radiologic vascular invasion [Exp(B) = 5.553, 95%CI: 2.269-14.589, P = 0.002] were independent predictive factors for neoadjuvant treatment. Borderline resectability [Exp(B) = 0.222, P = 0.008], pancreatic head cancer involving the pancreatic neck [Exp(B) = 9.461, P = 0.001] and arterial invasion [Exp(B) = 6.208, P = 0.010], and adjusted CA19-9 ≥ 50 [Exp(B) = 1.972 P = 0.019] were identified as prognostic clinical factors to predict tumor ***: The suggested preoperative defining system can help with designing treatment plans and also predict oncologic outcomes.

关键词： Preoperative defining system Pancreas head cancer Borderline resectable Adjusted CA19-9 Neoadjuvant therapy

Estimation of genetic parameters on growth characteristics of a 35-year-old Pinus koraiensis progeny trial in South Korea

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Journal of Forestry Research 2021年第5期32卷 2227-2236页

作者： Kyungmi Lee In Sik Kim seok woo Lee Division of Forest Tree Improvement Department of Forest BioresourcesNational Institute of Forest ScienceSuwonRepublic of Korea

The effects of genetic and environmental factors on Pinus koraiensis growth were studied based on a35 year-old progeny trial composed of open-pollinated offspring of twenty-one plus ***,DBH and volume of the offspring was analyzed using restricted maximum likelihood/best linear unbiased prediction in mixed model *** site and family effects on the three traits were *** distinct growth of offspring by site with disparate climates corroborated the importance of planting species in suitable *** differences by family was significant,emphasizing the importance of identifying families with either superior or inferior *** parental ranking was assigned in the sites,inferring the breeding value of each plus *** estimates of individual heritability(h_(i)^(2))of height,DBH and volume growth were 0.169-0.645,0.108-0.331 and 0.129-0.343 respectively,with higher h_(i)^(2) of the height than DBH on each *** of variance of genetic effect was higher with DBH in some cases,indicating the scope for selection is larger for this trait despite the lower heritability compared to *** the variation between families in terms of the performance stability across sites,consideration of the genotype by environment interaction is required in selecting materials to be used in reforestation with Korean pine.A few families with either superior or inferior performance retained their parental ranking for at least a *** families with increased growth on a particular site were identified,indicating their high breeding value and low *** in the genetic performance of the families by site requires delineation of the breeding region of the species.

关键词： Pinus koraiensis Genetic parameters Genotype by environment interaction Tree improvement Progeny trial

Characteristics of machined surface controlled by cutting tools and conditions in machining of brittle material

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中国有色金属学会会刊：英文版 2009年第B9期19卷 194-201页

作者： Yong-woo KIM Soo-chang CHOI Jeung-woo PARK Deug-woo LEE Department of Nano Fusion Technology Pusan National University Department of Mechanical Design Engineering Chosun University Department of Nanosystem and Nanoprocess Engineering Pusan National University

One of the ultra-precision machining methods was adapted for brittle material as well as soft material by using multi-arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because the particles of grinding tools are irregular size and material can be fragile. Therefore, we were able to design tool paths and machine controlled pattern on surface by multi-arrayed diamond tips with uniform size made in MEMS fabrication and high speed spindle, and the maximum speed was about 3×105 r/min. We defined several parameters that can affect the machining surface. Those were multi-array of diamond tips (n×n), speed of air spindle and feeding rate. The surface roughness and surface texture can be controlled by those parameters for micro machining.

关键词：加工表面脆性材料条件控制刀具路径表面粗糙度特征高速主轴加工方法