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Comparative toxicity of silver nanoparticles and silver ions to Escherichia coli

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Journal of Environmental Sciences 2018年第4期30卷 50-60页

作者： Yoojin Choi hyun-A kim Kyoung-Woong kim Byung-Tae Lee Department of Chemical and Biomolecular Engineering (BK21 Plus Program) Korea Advanced Institute of Science and Technology (KAIST) School of Earth Sciences and Environmental Engineering Gwangju Institute of Science and Technology (GIST)

With the increase in silver（Ag）-based products in our lives, it is essential to test the potential toxicity of silver nanoparticles（Ag NPs） and silver ions（Ag ions） on living organisms under various conditions. Here, we investigated the toxicity of Ag NPs with Ag ions to Escherichia coli K-12 strain under various conditions. We observed that both Ag NPs and Ag ions display antibacterial activities, and that Ag ions had higher toxicity to E. coli K-12 strain than Ag NPs under the same concentrations. To understand the toxicity of Ag NPs at a cellular level, reactive oxygen species（ROS） enzymes were detected for use as antioxidant enzymatic biomarkers. We have also studied the toxicity of Ag NPs and Ag ions under various coexistence conditions including： fixed total concentration, with a varied the ratio of Ag NPs to Ag ions; fixed the Ag NPs concentration and then increased the Ag ions concentration; fixed Ag ions concentration and then increasing the Ag NPs *** to Ag NPs and Ag ions clearly had synergistic toxicity; however, decreased toxicity（for a fixed Ag NPs concentration of 5 mg/L, after increasing the Ag ions concentration） to E. coli K-12 strain. Ag NPs and Ag ions in the presence of L-cysteine accelerated the bacterial cell growth rate, thereby reducing the bioavailability of Ag ions released from Ag NPs under the single and coexistence conditions. Further works are needed to consider this potential for Ag NPs and Ag ions toxicity across a range of environmental *** Significance Statement： As silver nanoparticles（Ag NPs）-based products are being broadly used in commercial industries, an ecotoxicological understanding of the Ag NPs being released into the environment should be further considered. Here, we investigate the comparative toxicity of Ag NPs and silver ions（Ag ions） to Escherichia coli K-12 strain, a representative ecotoxicological bioreporter. This study showed that toxicities of Ag NPs and Ag ions to E. coli

关键词： Nanotoxicity Silver nanoparticles Silver ions Coexist condition Escherichia coli

Numerical Study on Air Turbines with Enhanced Techniques for OWC Wave Energy Conversion

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China Ocean Engineering 2017年第5期31卷 517-527页

作者： CUI Ying hyun Beom-Soo kim Kilwon Department of Ocean Engineering College of EngineeringOcean University of China Division of Naval Architecture and Ocean Engineering Korea Maritime and Ocean University

In recent years,the oscillating water column(OWC) wave energy converter,which can capture wave energy from the ocean,has been widely applied all over the *** the essential part of the OWC system,the impulse and Wells turbines are capable of converting the low pressure pneumatic energy into the mechanical shaft *** an enhanced technique,the design of endplate or ring attached to the blade tip is investigated numerically in this paper.3 D numerical models based on a CFD-software FLUENT 12.0 are established and validated by the corresponding experimental results from the reports of Setoguchi et al.(2004) and Takao et al.(2001).Then the flow fields and non-dimensional evaluating coefficients are calculated and analyzed under steady *** show that the efficiency of impulse turbine with ring can reach up to 0.49 when Ф=1,which is 4% higher than that in the cases for the endplate-type and the original *** the ring-type Wells turbine with fixed guide vanes shows the best performance with the maximal efficiency of 0.55,which is 22% higher than that of the original *** addition,the quasi-steady analysis is used to calculate the mean efficiency and output-work of a wave cycle under sinusoidal flow *** all together,this study provides support for structural optimization of impulse turbine and Wells turbine in the future.

关键词： OWC impulse turbine Wells turbine CFD endplate ring quasi-steady analysis

Development of a fault-rupture environment in 3D: A numerical tool for examining the mechanical impact of a fault on underground excavations

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International Journal of Mining Science and Technology 2019年第1期29卷 105-111页

作者： Bo-hyun kim Mark K.Larson Spokane Mining Research Division CDC/NIOSH

While faults are commonly simulated as a single planar or non-planar interface for a safety or stability analysis in underground mining excavation, the real 3D structure of a fault is often very complex, with different branches that reactivate at different times. Furthermore, these branches are zones of nonzero thickness where material continuously undergoes damage even during interseismic periods. In this study, the initiation and the initial evolution of a strike-slip fault was modeled using the FLAC3D software program. The initial and boundary conditions are simplified, and mimic the Riedel shear experiment and the constitutive model in the literature. The FLAC3D model successfully replicates and creates the 3D fault zone as a strike-slip type structure in the entire thickness of the model. The strike-slip fault structure and normal displacement result in the formation of valleys in the model. Three panels of a longwall excavation are virtually placed and excavated beneath a main valley. The characteristics of stored and dissipated energy associated with the panel excavations are examined and observed at different stages of shear strain in the fault to evaluate bump potential. Depending on the shear strain in the fault, the energy characteristics adjacent to the longwall panels present different degrees of bump potential, which is not possible to capture by conventional fault simulation using an interface.

关键词： 3D fault zone Strike-slip fault FLAC3D Bump potential Energy characteristics

Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

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Particuology 2011年第6期9卷 606-610页

作者： Dae Seong kim Sang Bum Hong Jung-taek Kwon Kihong Park Department of Environmental Science and Engineering Gwangju Institute of Science and Technology Korea Polar Research Institute Laboratory of Toxicology College of Veterinary Medicine Seoul National University

Three types of water-based condensational growth systems, which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis, were evaluated. The first one is a mixing type growth system where aerosols are mixed with saturated water vapor, the second one is a thermal diffusive growth system where warm flow enters cold-walled tube, and the third one is a laminar flow type where cold flow enters a warm wet-wall tube. Hygroscopic sodium chloride （NaCl）, ammonium sulfate （（NH4）2SO4） and ammonium nitrate （NH4N03）, and non-hygroscopic polystyrene latex （PSL） particles, in the size range of 50-400 nm, were used to determine their growth factors through the growth systems. Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property. Collection efficiency of particles in the size range of 0.05-2.5 μm, in a continuous aerosol sampler after they passed through the third-type growth system was about 100%, suggesting that the third-type growth system would he the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles.

关键词： Particle growth chamber Condensational growth Particle sampler Hygroscopic particles

Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies

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Signal Transduction and Targeted Therapy 2024年第1期9卷 173-210页

作者： Md Entaz Bahar hyun Joon kim Deok Ryong kim Department of Biochemistry and Convergence Medical Sciences and Institute of Medical Science Gyeongsang National UniversityCollege of MedicineJinjuSouth Korea Department of Anatomy and Convergence Medical Sciences and Institute of Medical Science Gyeongsang National UniversityCollege of MedicineJinjuSouth Korea

Metastatic dissemination of solid tumors,a leading cause of cancer-related mortality,underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis,chemoresistance,and the mechanistic backgrounds of individuals whose cancers are prone to *** most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase(MAPK)pathway,encompassing the RAS–RAF–MAPK kinase(MEK)–extracellular signal-related kinase(ERK)*** kinase is a primary mediator of the MAPK pathway,responsible for the sequential activation of downstream targets,such as MEK and the transcription factor ERK,which control numerous cellular and physiological processes,including organism development,cell cycle control,cell proliferation and differentiation,cell survival,and *** in this signaling cascade are associated with diseases such as *** inhibitors(RAFi)combined with MEK blockers represent an FDAapproved therapeutic strategy for numerous RAF-mutant cancers,including melanoma,non-small cell lung carcinoma,and thyroid ***,the development of therapy resistance by cancer cells remains an important ***,an intracellular lysosome-dependent catabolic recycling process,plays a critical role in the development of RAFi resistance in ***,targeting RAF and autophagy could be novel treatment strategies for RAF-mutant *** this review,we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and ***,we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic ***,this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.

关键词： RAF insight mechanism

Endoscopic papillary large balloon dilation in patients with periampullary diverticula

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World Journal of Gastroenterology 2013年第41期19卷 7168-7176页

作者： Kook hyun kim Tae Nyeun kim Division of Gastroenterology and Hepatology Department of Internal medicineYeungnam University College of MedicineDaegu 705-717South Korea

AIM:To evaluate the safety and effectiveness of endoscopic papillary large balloon dilation(EPLBD)for bile duct stone extraction in patients with periampullary ***:The records of 223 patients with large common bile duct stones(≥10 mm)who underwent EPLBD(12-20 mm balloon diameter)with or without limited endoscopic sphincterotomy(ES)from July 2006to April 2011 were retrospectively *** these patients,93(41.7%)had periampullary diverticula(PAD),which was categorized into three *** clinical variables of EPLBD with limited ES(EPLBD+ES)and EPLBD alone were analyzed according to the presence of ***:Patients with PAD were significantly older than those without(75.2±8.8 years vs 69.7±10.9years,P=0.000).The rates of overall stone removal and complete stone removal in the first session were not significantly different between the PAD and nonPAD groups,however,there was significantly less need for mechanical lithotripsy in the PAD group(3.2%vs 11.5%,P=0.026).Overall stone removal rates,complete stone removal rates in the first session and the use of mechanical lithotripsy were not significantly different between EPLBD+ES and EPLBD alone in patients with PAD(96.6%vs 97.1%;72.9%vs 88.2%;and 5.1%vs 0%,respectively).No significant differences with respect to the rates of pancreatitis,perforation,and bleeding were observed between EPLBD+ES and EPLBD alone in the PAD group(3.4%vs 14.7%,P=0.095;0%vs 0%;and 3.4%vs 8.8%,P=0.351,respectively).CONCLUSION:EPLBD with limited ES and EPLBD alone are safe and effective modalities for common bile duct stone removal in patients with PAD,regardless of PAD subtypes.

关键词： Endoscopic papillary large balloon dilation Endoscopic sphincterotomy Periampullary diverticula

Chemical surface tuning of zinc metal anode toward stable,dendrite-less aqueous zinc-ion batteries

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Journal of Energy Chemistry 2023年第11期86卷 1-8,I0001页

作者： Pranav Kulkarni Sun-Sik kim hyun Young Jung Department of Energy Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea Department of Energy System Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea

The commercialization of Zn batteries is confronted with urgent challenges in the metal anode,such as dendrite formation,capacity loss,and cracking or ***,surface interfacial engineering of the Zn anode is introduced for achieving safety and dendritic-free cycling for high-performance aqueous Zn batteries through a simple but highly effective chemical etching-substitution *** chemical modification induces a rough peak-valley surface with a thin fluorine-rich interfacial layer on the Zn anode surface,which regulates the growth orientation via guiding uniform Zn plating/stripping,significantly enhances accessibility to aqueous electrolytes and improves wettability by reducing surface *** a result,such a synergetic surface effect enables uniform Zn plating/stripping with low polarization of 29 m V at a current density of 0.5 m A cm^(-2) with stable cyclic performance up to 1000 ***,a full cell composed of a fluorine-substituted Zn anode coupled with aβ-MnO_(2)or Ba-V_(6)O_(13)cathode demonstrates improved capacity retention to 1000 cycles compared to the pristine-Zn *** proposed valley deposition model provides the practical direction of surface-modified interfacial chemistries for improving the electrochemical properties of multivalent metal anodes via surface tuning.

关键词： Dendrite free Peak-Valley surface Zinc-ion batteries Surface modification Fluorinated interface

Integration of earth-abundant cocatalysts for high-performance photoelectrochemical energy conversion

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Journal of Energy Chemistry 2024年第1期88卷 336-355,I0008页

作者： Joonhee Ma Sang hyun Ahn Soo Young kim Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea School of Chemical Engineering and Materials Science Chung-Ang University84 Heukseok-roDongjak-guSeoul 06974Republic of Korea

Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and *** utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added ***,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical ***,significant research has been conducted to improve the overall conversion efficiency of PEC *** particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy *** review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) *** main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/***,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based *** addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with ***,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.

关键词： Solar energy Photo-electrochemical Water splitting CO_(2)reduction Cocatalysts

Comparison of the impact of endoscopic retrograde cholangiopancreatography between pre-COVID-19 and current COVID-19 outbreaks in South Korea:Retrospective survey

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World Journal of Clinical Cases 2021年第28期9卷 8404-8412页

作者： Kook hyun kim Sung Bum kim Division of Gastroenterology and HepatologyDepartment of Internal Medicine Yeungnam UniversityCollege of MedicineDaegu 42415South Korea

BACKGROUND The coronavirus disease 2019(COVID-19)outbreak has markedly influenced the endoscopic *** retrograde cholangiopancreatography(ERCP)is an essential technique for pancreatobiliary disease but increases the risk of exposure to the virus-containing body fluid;however,the impact of COVID-19 on ERCP is *** To compare the number of endoscopic activities and to analyze the clinical outcomes of ERCPs before and during the COVID-19 outbreak in Daegu,South *** This retrospective cohort study included patients aged≥18 years who underwent ERCP between February 18 and March 28,2020,at a tertiary *** indications and endoscopic details were compared with those from the same period in 2018 and 2019 as control *** Of the 269 ERCP procedures,113(42.0%)cases were performed as emergency *** number of ERCP procedures in 2018 and 2019 decreased by 20.2%and 56.6%,respectively,compared with that in 2020(P<0.01);among the 113 emergency ERCPs,the observed numbers in 2018(n=42)and 2019(n=55)dramatically dropped by 61.9%and 70.9%,respectively,compared with that in 2020(n=16).Of the 16 cases in 2020,stone removal was performed in five,biliary stenting in five,sphincterotomy in five,and nasobiliary drainage in *** case of ERCP-related infection in medical workers or other patients has been *** The COVID-19 outbreak significantly reduced the number of ERCPs;however,there is no difference in the indications and endoscopic interventions before and during the COVID-19 outbreak.

关键词： Coronavirus disease 2019 Coronavirus Endoscopic retrograde cholangi-opancreatography Emergency endoscopic retrograde cholangiopancreatography Endoscopy