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Ultrafast synthesis of gold nanoparticles on cellulose nanocrystals via microwave irradiation and their dyes-degradation catalytic activity

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Journal of Materials Science & Technology 2020年第6期41卷 168-177页

作者： Madhusudhan Alle seung-hwan lee Jin-Chul Kim Institute of Forest Science Kangwon National UniversityChuncheon 24341Republic of Korea Department of Forest Biomaterials Engineering Kangwon National UniversityChuncheon 24341Republic of Korea Department of Medical Biomaterials Engineering College of Biomedical Science and Institute of Bioscience and BiotechnologyKangwon National University192-1Hyoja 2 dongChuncheonKangwon-do 200-701Republic of Korea

This study represents a well-dispersed gold nanoparticles(AuNPs)synthesis process via cellulose nanocrystals(CNC)which acts as both reducing and supporting *** synthesis process was ultrafast and completed in a few seconds using microwave *** entire synthesis process was cost-effective,sustainable and *** synthesized(AuNPs/CNC)nanocomposite was investigated by transmission electron microscopy,selected area electron diffraction,Fourier transform infrared spectroscopy,energy dispersive X-ray analysis,X-ray diffraction,and UV–vis *** obtained AuNPs were well accumulated on the CNC surface and had a uniform spherical shape with an average diameter of 8±5.3 *** diameter of AuNPs could be altered by tuning the concentration of CNC *** synthesized AuNPs/CNC nanocomposite film exhibited excellent degradation properties against various organic dyes,namely,Allura red,Congo red,Rhodamine B and *** ultrafast degradation reactions followed pseudo first order *** the catalytic degradation reaction,AuNPs/CNC was transmitting electrons from a donor(NaBH4)to an acceptor(a dye).

关键词： Cellulose nanocrystals Gold nanoparticles Microwave synthesis Catalytic degradation of dyes

Nanoscale resistive switching devices for memory and computing applications

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Nano Research 2020年第5期13卷 1228-1243页

作者： seung hwan lee Xiaojian Zhu Wei D.Lu Department of Electrical Engineering and Computer Science The University of MichiganAnn ArborMichigan 48109USA

With the slowing down of the Moore’s law and fundamental limitations due to the von-Neumann bottleneck,continued improvements in computing hardware performance become increasingly more *** switching(RS)devices are being extensively studied as promising candidates for next generation memory and computing applications due to their fast switching speed,excellent endurance and retention,and scaling and three-dimensional(3D)stacking *** particular,RS devices offer the potential to natively emulate the functions and structures of synapses and neurons,allowing them to efficiently implement neural networks(NNs)and other in-memory computing systems for data intensive applications such as machine learning *** this review,we will examine the mechanisms of RS effects and discuss recent progresses in the application of RS devices for memory,deep learning accelerator,and more faithful brain-inspired computing *** and possible solutions at the device,algorithm,and system levels will also be discussed.

关键词： resistive switching oxygen vacancy metal cation memory application in-memory computing bio-inspired application

The TNFα/TNFR2 axis mediates natural killer cell proliferation by promoting aerobic glycolysis

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Cellular & Molecular Immunology 2023年第10期20卷 1140-1155页

作者： Abrar Ul Haq Khan Alaa Kassim Ali Bryan Marr Donghyeon Jo Simin Ahmadvand Claire Fong-McMaster Saeedah Musaed Almutairi Lisheng Wang Subash Sad Mary-Ellen Harper seung-hwan lee Department of Biochemistry Microbiologyand ImmunologyFaculty of MedicineUniversity of OttawaOttawaONCanada The University of Ottawa Centre for Infection Immunityand InflammationOttawaONCanada Botany and Microbiology Department College of SciencesKing Saud UniversityRiyadhSaudi Arabia

Natural killer(NK)cells are predominant innate lymphocytes that initiate the early immune response during *** cells undergo a metabolic switch to fuel augmented proliferation and activation following *** necrosis factor-alpha(TNFα)is a well-known inflammatory cytokine that enhances NK cell function;however,the mechanism underlying NK cell proliferation in response to TNFαis not well ***,we demonstrated that upon infection/inflammation,NK cells upregulate the expression of TNF receptor 2(TNFR2),which is associated with increased proliferation,metabolic activity,and effector ***,IL-18 can induce TNFR2 expression in NK cells,augmenting their sensitivity toward TNFα.Mechanistically,TNFα-TNFR2 signaling upregulates the expression of CD25(IL-2Rα)and nutrient transporters in NK cells,leading to a metabolic switch toward aerobic *** analysis revealed significantly reduced expression levels of genes involved in cellular metabolism and proliferation in NK cells from TNFR2 KO ***,our data affirmed that genetic ablation of TNFR2 curtails CD25 upregulation and TNFα-induced glycolysis,leading to impaired NK cell proliferation and antiviral function during MCMV infection in ***,our results delineate the crucial role of the TNFα-TNFR2 axis in NK cell proliferation,glycolysis,and effector function.

关键词： Natural killer cells TNFa TNFR2 Glycolysis Proliferation Murine cytomegalovirus

Advances in wearable and implantable bioelectronics for precision medicine

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Bio-Design and Manufacturing 2024年第4期7卷 383-387页

作者： Kaichen Xu seung hwan Ko Jun Chen State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310058China Applied Nano and Thermal Science Lab Department of Mechanical EngineeringSeoul National UniversitySeoul 08826Republic of Korea Department of Bioengineering University of CaliforniaLos AngelesLos AngelesCA 90095-1599USA

The continuous pursuit for a better quality of life promotes continuous advancements in intelligent *** wearable and implantable bioelectronics have emerged as an innovative complement to rigid material-based electronic devices[1-3].Due to their distinct advantages in terms of ductile,ultrathin,and biocompatible features,these elastic and soft bioelectronic devices can be seamlessly mounted onto various real or artificial tissues and organs.

关键词： wear mounted pursuit

Effects of obesity on lower urinary tract symptoms in Korean BPH patients

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Asian Journal of Andrology 2009年第6期11卷 663-668页

作者： seung hwan lee Joon Chul Kim Ji-Youl lee Jang hwan Kim Cheol Young Oh seung Wook lee Se Jeong Yoo Byung Ha Chung Department of Urology Yonsei University Health System Seoul 135-720 Korea Department of Urology The Catholic University of Korea Seoul 137-701 Korea Department of Urology Hallym University Chuncheon 200-704 Korea Department of Urology Eulji Medical Center Eulji University Seoul 139-230 Korea

We analyzed the effects of obesity on lower urinary tract symptoms （LUTSs） in Korean benign prostatic hyperplasia （BPH） patients. This is a multicenter, cross-sectional, prospective study conducted in four centers in Korea. A total of 602 men with LUTSs secondary to BPH were included. BPH/LUTSs cases were men aged ≥ 40 years with intemational prostate symptom scores （IPSS） ≥ 8 points. Height, weight and waist circumference were measured. Among the 602 patients, 156 patients had a waist circumference above 90 cm, representing central obesity, and 215 patients had a body mass index above 25 kg m2. Waist circumference was positively correlated with prostate volume （P = 0.034）. Men with waist circumference 〉 90 cm experienced a 1.36-fold increased risk of severe LUTSs （95% CI 0.82-2.41） compared with men with waist circumference ≤ 90 cm. Prostate volume was positively correlated with urgency and nocturia in men with central obesity. In this population of Korean men diagnosed with BPH, central obesity rather than overall obesity seems to be the more important predictor of LUTSs correlated with BPH.

关键词： benign prostatic hyperplasia central obesity lower urinary tract symptom prostate

Successful recanalization of chronic total occlusion of the superior mesenteric artery by transradial approach

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第8期11卷 627-630页

作者： Woo Taek KIM Sung Gyun AHN Jun-Won lee Joong Kyung SUNG seung hwan lee Junghan YOON Division of Cardiology Wonju College of MedicineYonsei University

It is a challenge to confirm chronic mesenteric ischemia(CMI) as a cause of gastrointestinal(GI) symptoms such as postprandial epigastric bloating,anorexia,and debilitating weight *** intervention for CMI has been gaining popularity because of the high morbidity associated with surgical ***,in EVI for superior mesenteric artery(SMA) occlusion,the transfemoral approach is limited by difficulty in coaxial alignment of the guiding catheter,which leads to insufficient back-up ***,we report on a 58-year-old male patient with chronic total occlusion of the SMA,which was successfully revascularized by endovascular intervention via the left radial *** endovascular therapy may be another treatment option for the treatment of CMI.

关键词： Transluminal angioplasty Radial artery Superior mesenteric artery Chronic mesenteric ischemia

Machine-learned wearable sensors for real-time hand-motion recognition: toward practical applications

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National Science Review 2024年第2期11卷 231-263页

作者： Kyung Rok Pyun Kangkyu Kwon Myung Jin Yoo Kyun Kyu Kim Dohyeon Gong Woon-Hong Yeo seungyong Han seung hwan Ko Department of Mechanical Engineering Seoul National University IEN Center for Human-Centric Interfaces and Engineering Institute for Electronics and NanotechnologyGeorgia Institute of Technology School of Electrical and Computer Engineering Georgia Institute of Technology Department of Chemical Engineering Stanford University Department of Mechanical Engineering Ajou University George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology Institute of Advanced Machinery and Design(SNU-IAMD) Seoul National University

Soft electromechanical sensors have led to a new paradigm of electronic devices for novel motion-based wearable applications in our daily lives. However, the vast amount of random and unidentified signals generated by complex body motions has hindered the precise recognition and practical application of this technology. Recent advancements in artificial-intelligence technology have enabled significant strides in extracting features from massive and intricate data sets, thereby presenting a breakthrough in utilizing wearable sensors for practical applications. Beyond traditional machine-learning techniques for classifying simple gestures, advanced machine-learning algorithms have been developed to handle more complex and nuanced motion-based tasks with restricted training data sets. Machine-learning techniques have improved the ability to perceive, and thus machine-learned wearable soft sensors have enabled accurate and rapid human-gesture recognition, providing real-time feedback to users. This forms a crucial component of future wearable electronics, contributing to a robust human–machine interface. In this review, we provide a comprehensive summary covering materials, structures and machine-learning algorithms for hand-gesture recognition and possible practical applications through machine-learned wearable electromechanical sensors.

关键词： wearable sensor soft electronics artificial intelligence machine learning human–machine interfaces gesture recognition

Continuous live cell imaging of cellulose attachment by microbes under anaerobic and thermophilic conditions using confocal microscopy

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Journal of Environmental Sciences 2013年第5期25卷 849-856页

作者： Zhi-Wu Wang seung-hwan lee James G.Elkins Yongchao Li Scott Hamilton-Brehm Jennifer L.Morrell-Falvey BioEnergy Science Center Biosciences DivisionOak Ridge National LaboratoryOak RidgeTN 37831USA College of Food Agricultural and Environmental SciencesThe Ohio State University1328 Dover RdWoosterOH 44691USA National Institute of Advanced Industrial Science and Technology Biomass Refinery Research CenterHiroshimaJapan Department of Forest Biomaterials Engineering College of Forest and Environmental SciencesKangwon National UniversityChuncheon 200-701Korea

Live cell imaging methods provide important insights into the dynamics of cellular processes that cannot be derived easily from population-averaged *** the bioenergy field,much research is focused on fermentation of cellulosic biomass by thermophilic microbes to produce biofuels;however,little effort is dedicated to the development of imaging tools to monitor this dynamic biological *** is,in part,due to the experimental challenges of imaging cells under both anaerobic and thermophilic *** an imaging system is described that integrates confocal microscopy,a flow cell device,and a lipophilic dye to visualize *** to technical obstacles regarding suitable fluorescent markers,photodamage during imaging,and maintenance of environmental conditions during imaging are *** system was utilized to observe cellulose colonization by Clostridium thermocellum under anaerobic conditions at 60℃.This method enables live cell imaging of bacterial growth under anaerobic and thermophilic conditions and should be widely applicable to visualizing different cell types or processes in real time.

关键词： thermophile lipophilic dye cellulose biofuel confocal laser scanning microscopy biofilm

Comparison of the clinical efficacy of medical treatment of symptomatic benign prostatic hyperplasia between normal and obese patients

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Asian Journal of Andrology 2011年第5期13卷 728-731页

作者： seung hwan lee Cheol Young Oh Kyung Kgi Park Mutt Su Chung Se Jeong Yoo Byung Ha Chung Department of Urology Yonsei University Health System Seoul Korea Department of Urology Hallym University Anyang 431-070 Chuncheon

We aimed to investigate the difference in efficacy of medical treatment of symptomatic benign prostatic hyperplasia （BPH） between normal and obese patients with BPH; obesity was determined by either body mass index （BMI） or waist circumference （WC）. In this 12-week prospective observational study, a total of 175 patients aged ≥40 years with International Prostate Symptom Scores （IPSS） ≥12 points and prostate volume≥20 ml were prospectively enrolled. The patients were divided into two groups according to BMI or WC. Patients received the doxazosin gastrointestinal therapeutic system （GITS） at a dose of 4 mg once per day for 12 weeks. The changes from baseline in the IPSS, maximal urinary flow rate （Qmax）, post-void residual volume, quality of life （QoL） scores and adverse events （AEs） were analysed. Of the 175 enrolled patients, 132 completed the study. Sixty-seven patients had BMI 〉23 kg m-2, and 43 had WC 〉90 cm. Obese patients represented by WC 〉90 cm or BMI≥ 23 kg m-2 had a significantly greater prostate volume compared with non-obese patients at baseline. Total IPSS was significantly higher in the WC 〉90 cm group compared to the WC ≤ 90 cm group. Total I PSS was positively correlated with prostate volume （P=-0.031） and WC （P=0.045）. All groups showed significant improvements in total IPSS and QoL at 12 weeks. However, the improvement of total IPSS was greater in the high-BMI and high-WC groups. The most frequent AE was dizziness （n= 13）, and it was significantly lower in the obese BPH patients. Obesity was associated with increased prostate volume and lower urinary tract symptoms. Alpha-blockers appear to be efficacious for controlling symptoms, especially in obese men.

关键词： Alpha-blocker benign prostatic hyperplasia body mass index prostate waist circumference