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Ex situ aging effect on sulfonated poly(ether ether ketone) membrane:Hydration-dehydration cycling and hydrothermal treatment

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Journal of Energy Chemistry 2022年第7期31卷 583-592,I0014页

作者： seung-Young Choi Kyeong Sik jin Polymer&Materials Chemistry Department of ChemistryLund UniversitySE-22100Sweden Center for Hydrogen·Fuel Cell Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and Technology(POSTECH)PohangKyungbuk 37673Republic of Korea

Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation provides incremental proton conductivity to the membranes, whereas mechanical degradation drastically reduces device stability. On this basis, we describe here the effects of two different ex situ aging processes on sulfonated poly(ether ether ketone) membranes: hydrationdehydration cycling and prolonged hydrothermal treatment. Both aged membranes exhibited enhanced phase separation under the hydrated conditions, as characterized by small angle X-ray ***, when the aged membranes were dried again, the nanostructure of the membranes aged via the hydration-dehydration cycling was recoverable, whereas that of the membranes aged via prolonged hydrothermal treatment was irreversible. Furthermore, the two differently aged membranes showed clear differences in thermal, mechanical, and electrochemical properties. Finally, we implemented both aged membranes in fuel cell application. The sample aged via hydration-dehydration cycling maintained its improved cell performance, whereas the sample aged via hydrothermal treatment showed drastically reduced cell performance after durability test for 50 h.

关键词： Sulfonated poly(ether ether ketone) Humidity cycle test Ex situ aging Proton exchange membrane Fuel cell

Progress in light-to-frequency conversion circuits based on low dimensional semiconductors

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Nano Research 2021年第9期14卷 2938-2964页

作者： seung Gi Seo seung Yeob Kim jinheon Jeong Sung Hun jin Department of Electronic Engineering Incheon National UniversityAcademy-ro 119Yeongsu-guIncheon 22012Republic of Korea

As the scaling down of Si devices in the range less than few nm has been expedited up to a physical limit of Si,low dimensional materials have been regarded as one of next generation *** a variety of applications,studies on photodetectors have been actively investigated with their novel optical properties as well as astonishing electrical ***,most of research has focused on single device-type photodetector(i.e.,photo-diode or photo-transistor).Contrary to common photodetector,light-to-frequency circuits(LFCs)are based on frequency reading with photosensitive ring oscillators,which has better noise immunity and reduced system complexity,thus,can be utilized to novel application even in internet of things(loT)and bio&medical *** this review,low dimensional materials based circuit level photodetectors,which are core elements as the form of either inverters or ring oscillators for demonstration of LFCs,are *** with the introduction of low dimensional materials and their optical properties for optoelectronics,a fundamental concept for LFCs is specifically ***,research progress on low dimensional material based photosensitive inverters is addressed according to the types of ***,as one of practical method for the improvement of photodetector performance,molecular doping technology is ***,complete system of LFCs and its digitization for demonstration of production level,and potential application in the respective four aspects,(i)medical SpO_(2) detection,(ii)biological fluidic system,(iii)auto-lighting in agriculture,and(iv)optical feedback and sensing systems,are presented as systematic way to address the envisioned practical applications for the future displays including virtual reality and augmented reality,and *** a remark,LFCs based on low dimensional semiconductors are expected to be one of core components in trillion’s sensor area.

关键词： photodetector light-to-frequency conversion circuit transition metal dichalcogenide carbon nanotube

Selective apoptotic effect of Zelkova serrata twig extract on mouth epidermoid carcinoma through p53 activation

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International Journal of Oral Science 2012年第2期4卷 78-84页

作者： Hoe-jin Kang Young-joo Jang Laboratory of Cell Cycle and Signal Transduction World Class University Research Department of Nanobiomedical Science and Institute of Tissue Regeneration EngineeringDankook UniversityCheonanKorea

Apoptosis or programmed cell death plays an essential role in chemotherapy-induced tumor cell killing, and inducers of apoptosis are commonly used in cancer therapy. Treatment with Zelkova serrata extracts was performed in human gingival fibroblast （HGF）, mouth epidermoid carcinoma cell （KB）, lower gingival squamous cancer cell （YD38） and tongue mucoepidermoid carcinoma cells （YD15）. We observed that extract prepared from Zelkova serrata twig selectively inhibited proliferation of various oral cancer cells, but not normal gingival fibroblasts, in a dose-dependent manner. Caspase-8-mediated apoptosis was induced by treatment with the extract only in mouth epidermoid carcinoma and not in other types of cancer cells, including lower gingival squamous cell carcinoma. The selective apoptotic effect of Zelkova serrata twig extract in mouth epidermoid carcinoma was dependent on normal p53 status. Apoptosis was not remarkably induced by treatment with the extract in either lower gingival squamous or tongue mucoepidermoid carcinoma cells, both of which contain abnormalities of p53. Upon treatment with Zelkova serrata twig extract, mouth epidermoid carcinoma cells accumulated in S phase by activation of p21. These data indicate that Zelkova serrata twig extract exerted a cancer type-specific, p53-dependent apoptotic effect and disturbed the cell cycle, which suggests that herbal medicine could be a treatment for specific types of cancers.

关键词： anticancer apoptosis oral carcinomas p53 Zelkova serrata

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

Green coffee bean extract improves obesity by decreasing body fat in high-fat diet-induced obese mice

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Asian Pacific Journal of Tropical Medicine 2016年第7期9卷 616-624页

作者： Bong-Keun Choi Sung-Bum Park Dong-Ryung Lee Hae jin Lee Ying-Yu jin seung Hwan Yang joo-Won Suh Nutra Pharm Tech Giheung-gu Interdisciplinary Program of Biomodulation Myongji University Center for Nutraceutical and Pharmaceutical Materials Myongji University

Objective:To evaluate possible lipid catabolism and body fat regulation effects of 3-caffeoylquinic acid in Green coffee bean extract(GCBE) in high-fat diet(HFD)-induced obese ***:Obesity was induced in mice using a HFD for four ***,mice were fed only HFD or HFD with GCBE at 50,100,and 200 mg/*** acid synthesis mechanism regulation of body fat was investigated through real-time PCR and Western blot *** fat reduction was measured through dual-energy X-ray ***:In HFD-induced obese mice,GCBE treatment significantly decreased body weight gain,liver weight and white adipose tissue weights with regulation of adipose tissue lipolysis hormones,like adiponectin and *** treatment decreased mR NA expression levels of adipogenesis and adipocyte metabolism related genes in adipose tissues and the liver,and decreased the corresponding protein *** energy X-ray absorptiometry measurements were used to compare body fat between mice on high-fat and those treated with *** treated mice had a lower fat mass compared to HFD alone fed mice and relative body weight and fat mass were markedly ***:GCBE has a potential anti-obesity effect with lowering body fat accumulation by regulating adipogenesis and lipid metabolism-related genes and proteins in WAT and liver.

关键词： Green coffee bean extract High-fat diet induced obese mice Adipogenesis Body fat Dual energy X-ray absorptiometry

Prediction models for recurrence in patients with small bowel bleeding

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World Journal of Clinical Cases 2023年第17期11卷 3949-3957页

作者： Ji Hyun Kim seung-joo Nam Division of Gastroenterology and Hepatology Department of Internal MedicineKangwon National University School of MedicineChuncheon 24341South Korea

Obscure gastrointestinal bleeding(OGIB)has traditionally been defined as gastrointestinal bleeding whose source remains unidentified after bidirectional *** can present as overt bleeding or occult bleeding,and small bowel lesions are the most common *** small bowel can be evaluated using capsule endoscopy,device-assisted enteroscopy,computed tomography enterography,or magnetic resonance *** the cause of smallbowel bleeding is identified and targeted therapeutic intervention is completed,the patient can be managed with routine ***,diagnostic tests may produce negative results,and some patients with small bowel bleeding,regardless of diagnostic findings,may experience *** those at risk of rebleeding can help clinicians form individualized surveillance *** studies have identified different factors associated with rebleeding,and a limited number of studies have attempted to create prediction models for *** article describes prediction models developed so far for identifying patients with OGIB who are at greater risk of *** models may aid clinicians in forming tailored patient management and surveillance.

关键词： Obscure gastrointestinal bleeding Prediction model Rebleeding Small bowel bleeding Video capsule endoscopy

Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water

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Journal of Environmental Sciences 2009年第1期21卷 23-29页

作者： Veeriah Jegatheesan seung Hyun Kim C. K. joo GAO Baoyu School of Engineering James Cook University Townsville QLD 4811 Australia. Department of Civil Engineering Kyungnam University 631-701 Masan Korea Chilseo Water Treatment Plant Haman 637-940 Korea School of Environmental Science and Engineering Shandong University Jinan 250100 China

In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chllseo Water Treatment Plant （CWTP） situated in Haman, Korea as well as the effluents from sand and granular activated carbon （GAC） filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting （FRA and SRA） organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products （DBPs）. If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

关键词： chlorine decay model initial concentration nitrogenous compounds organic and inorganic compounds reaction rate constants

Reversible and controllable threshold voltage modulation for n-channel MoS2 and p-channel MoTe_(2 )field-effect transistors via multiple counter doping with ODTS/poly-L-lysine charge enhancers

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Nano Research 2021年第9期14卷 3214-3227页

作者： seung Gi Seo jinheon Jeong seung Yeob Kim Ajit Kumar Sung Hun jin Department of Electronic Engineering Incheon National UniversityAcademy-ro 119Yeongsu-guIncheon 22012Republic of Korea

Confronted by the inherent physical limitations in scaling down Si technology,transition metal dichalcogenides(TMDCs)as alternatives are being tremendously researched and paid attention ***,mature counter doping technology for TMDCs is still elusive,and thus,a controllable and reversible charge enhancer is adopted for acceptor(or donor)-like doping via octadecyltrichlorosilane(ODTS)(or poly-L-lysine(PLL))***,multiple counter doping for TMDC field-effect transistors(FETs),combined with a threshold voltage(V;h)freezing scheme,renders the V_(th) modulation controllable,with negligible degradation and decent sustainability of FETs even after each treatment of a representative charge *** parallel,the counter doping mechanism is systematically investigated via photoluminescence spectroscopy,X-ray photoelectron spectroscopy,atomic force microscopy(AFM),surface energy characterization,and measurement of optoelectronic properties under illumination with light of various *** impressively,complementary inverters,composed of type-converted molybdenum ditelluride(MoTe_(2)>FETs and hetero-TMDC FETs in enhancement mode,are demonstrated via respective ODTS/PLL ***,driving backplane application for micro-light-emitting diode(p-LED)displays and physical validation of a corresponding counter doping scheme even for flexible polyethylene terephthalate(PET)substrates could be leveraged to relieve daunting challenges in the application of nanoscale Si-based three-dimensional(3D)stacked systems,with potential adoption of ultralow power and monolithic optical interconnection technology.

关键词： transition metal dichalcogenides(TMDCs) counter doping charge enhancer field-effect transistors micro-light-emitting diode(m-LED)

On-skin and tele-haptic application of mechanically decoupled taxel array on dynamically moving and soft surfaces

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npj Flexible Electronics 2022年第1期6卷 964-972页

作者： Se Young Kwon Gyeongsuk Park Hanbit jin Changyeon Gu seung jin Oh joo Yong Sim Wooseup Youm Taek-Soo Kim Hye jin Kim Steve Park Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Electronics and Telecommunications Research Institute(ETRI) Daejeon 34129Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Mechanical Systems Engineering Sookmyung Women’s UniversityDaejeon 04313Republic of Korea

To accurately probe the tactile information on soft skin,it is critical for the pressure sensing array to be free of noise and inter-taxel crosstalk,irrespective of the measurement ***,on dynamically moving and soft surfaces,which are common conditions for on-skin and robotic applications,obtaining precise measurement without compromising the sensing performance is a significant challenge due to mechanical coupling between the sensors and with the moving *** this work,multi-level architectural design of micro-pyramids and trapezoid-shaped mechanical barrier array was implemented to enable accurate spatiotemporal tactile sensing on soft surfaces under dynamic ***-off relationship between limit of detection and bending insensitivity was discovered,which was overcome by employing micropores in barrier ***,in-situ pressure mapping on dynamically moving soft surfaces without signal distortion is demonstrated while human skin and/or soft robots are performing complicated tasks such as reading Braille and handling the artificial organs.

关键词： artificial moving dynamically