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Comparative toxicity of silver nanoparticles and silver ions to Escherichia coli

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

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Standardized ileal digestible lysine requirements based on growth performance and histochemical characteristics of male broilers from 10 to 21 d of age

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Animal Nutrition 2023年第1期12卷 145-150页

作者： Su hyun An Boin Lee Young Min choi Changsu Kong Department of Animal Science and Biotechnology Kyungpook National University37224SangjuRepublic of Korea Department of Animal Science Kyungpook National University37224SangjuRepublic of Korea

The growth performance and histochemical characteristics of breast muscle fibers were used to estimate the standardized ileal digestible(SID)Lys requirements for 10-to 21-d-old male *** hundred and sixty 10-d-old Ross 308 broilers(290±16.6 g)were allocated to 6 diets in a randomized complete block design with 6 replicate cages per treatment and 10 birds per *** 6 experimental diets were formulated to contain equally spaced increasing levels of SID Lys from 0.86%to 1.36%.The data were analyzed using the MIXED procedure of *** Lys requirements were estimated by the NLIN procedure of *** increase in dietary SID Lys from 0.86%to 1.36%resulted in a quadratic increase(P<0.05)in body weight gain(BWG),gain to feed ratio(G:F),breast weight,muscle cross-sectional area(MCSA),and fiber *** SID Lys requirements based on the one-slope broken-line,quadratic line,the first intercept between the plateau of the one-slope broken-line and quadratic-line models and 95%of the upper asymptote of the quadratic-line model were estimated to be 1.01%,1.19%,1.08%,and 1.13%for BWG,1.06%,1.22%,1.11%,and 1.16%for G:F,1.10%,1.29%,1.19%,and 1.22%for breast weight,1.06%,1.22%,1.12%,and 1.16%for MCSA,and 1.14%,1.22%,1.16%,and 1.16%for breast muscle fiber area,*** was concluded that the SID Lys requirements for broilers at the age of 10 to 21 d depended on the response variables used for estimation,and that histochemical characteristics of breast muscle fibers could be good indicators for estimating SID Lys requirements.

关键词： Requirement Lysine Growth performance Muscle fiber characteristics Broiler chicken

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Sandwich-structure transferable free-form OLEDs for wearable and disposable skin wound photomedicine

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Light(Science & Applications) 2019年第1期8卷 96-110页

作者： Yongmin Jeon Hye-Ryung choi Jeong hyun Kwon Seungyeop choi Kyung Mi Nam Kyoung-Chan Park Kyung Cheol choi School of Electrical Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Department of Dermatology Seoul National University Bundang Hospital(SNUBH)Seongnam 13620Republic of Korea

Free-form optoelectronic devices can provide hyper-connectivity over space and ***,most conformable optoelectronic devices can only be fabricated on flat polymeric materials using low-temperature processes,limiting their application and *** paper presents free-form optoelectronic devices that are not dependent on the shape or *** medical applications,the transferable OLED(10μm)is formed in a sandwich structure with an ultra-thin transferable barrier(4.8μm).The results showed that the fabricated sandwich-structure transferable OLED(STOLED)exhibit the same high-efficiency performance on cylindricalshaped materials and on materials such as textile and *** the neutral axis is freely adjustable using the sandwich structure,the textile-based OLED achieved both folding reliability and washing reliability,as well as a long operating life(>150 h).When keratinocytes were irradiated with red STOLED light,cell proliferation and cell migration increased by 26 and 32%,*** the skin equivalent model,the epidermis thickness was increased by 39%;additionally,in organ culture,not only was the skin area increased by 14%,but also,reepithelialization was highly *** on the results,the STOLED is expected to be applicable in various wearable and disposable photomedical devices.

关键词： optoelectronic structure transfer

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BIOCOMPATIBILITY OF A PDMS-COATED MICRO-DEVICE:BLADDER VOLUME MONITORING SENSOR

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Chinese Journal of Polymer Science 2012年第2期30卷 242-249页

作者： Dong Sup Lee Su jin Kim Jun Ho Sohn In Gul Kim Sae Woong Kim Dong Wan Sohn Jong hyun Kim Bumkyoo choi Department of Urology St.Vincent's HospitalCollege of Medicinethe Catholic University of KoreaSuwonKorea Department of Urology Seoul St.Mary's HospitalCollege of Medicinethe Catholic University of KoreaSeoulKorea Department of Urology Yeouido St.Mary's HospitalCollege of Medicinethe Catholic University of KoreaSeoulKorea Department of Mechanical Engineering Sogang UniversitySeoulKorea

We evaluated the biocompatibility of a dimethylpolysiloxane-coated micro-device which had been designed for monitoring real-time bladder volume in previous studies. The extract assay with dimethylpolysiloxane which had been used for coating the micro-device to measure the bladder volume was performed as an in vitro cytotoxicity test. For in vivo biocompatibility testing, the inflammatory responses around the implantation site of the micro-device in subcutaneous tissue of rat were assessed by light microscope with H＆E stain and fluorescence microscope with ED1 stain and von Willebrand factor stain. The averages of cell viability in dimethylpolysiloxane group were 84.6% and 82.3% at 24 h and 72 h incubation, respectively. The qualitative evaluations with light and fluorescence microscope revealed that the inflammatory changes peaked during 2 weeks but almost disappeared at 4 weeks after implantation of devices. The quantitative evaluations for granulation layer formation and neovascularization showed that the thickness of the layer in dimethylpolysiloxane group peaked during 2 weeks but it came to be stabilized at 4 weeks as thin as at 2 weeks in control group, and the frequency of neovascularization was higher in dimethylpolysiloxane group than in control group but it was not increased with time. The dimethylpolysiloxane-coated micro-device is thought be a reliable bio-medical device.

关键词： Dimethylpolysiloxane Devices Biocompatibility testing.

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Pravastatin activates PPARα/PPARγexpression in the liver and gallbladder epithelium of hamsters

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Hepatobiliary & Pancreatic Diseases International 2011年第2期10卷 185-190页

作者： Seok Ho Dong jin Lee Dong Hee Koh Min Ho choi hyun Joo Jang Sea Hyub Kae Division of Gastroenterology Department of Internal MedicineKyung Hee University College of Medicine Division of Gastroenterology Department of Internal MedicineHallym University College of Medicine

BACKGROUND:Our earlier study with cultured gallbladder epithelial cells demonstrated that statins(HMG-CoA reductase inhibitors)activate the expression of PPARαand PPARγ, consequently blocking the production of pro-inflmmatory *** present study used hamsters to investigate the effects of pavastatin on PPARα/PPARγexpression in the liver and gallbladder epithelium,and to determine whether pravastatin suppresses cholesterol crystal formation in the gallbladder. METHODS:A total of 40 Golden Syrian male hamsters(4 weeks old)were randomly assigned to four groups(basal diet control; basal diet+pavastatin;high cholesterol diet;high cholesterol diet+pravastatin).All hamsters were 11 weeks old at the end of the *** liver,gallbladder and bile were harvested. Immunohistochemical staining and Western blotting for PPARαand PPARγwere performed in the liver and gallbladder. A drop of fresh bile was examined for cholesterol crystals under a microscope. RESULTS:In the gallbladder and liver of the hamsters, pravastatin activated the PPARαand PPARγexpression of gallbladder epithelial cells and hepatocytes,and particularly the response of PPARγwas much stronger than that of PPARα. Pravastatin suppressed the formation of cholesterol gallstones or crystals in the gallbladder. CONCLUSION:Pravastatin is an effective medication to activate PPARs(especially PPARγ)in the liver and the gallbladder epithelium of hamsters,and contributes to the prevention of gallstone formation.

关键词： pravastatin PPARα PPARγ hamster gallstone

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Metachronous bile duct cancer nine years after resection of gallbladder cancer

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World Journal of Gastroenterology 2009年第27期15卷 3440-3444页

作者： Hye jin Joo Gi hyun Kim Won Joong Jeon Hee Bok Chae Seon Mee Par Sei jin Youn Jae Woon choi Rohyun Sung Department of Internal Medicine College of Medicine Chungbuk National UniversityGaeshindong 62 Heungdukgu Cheongju 361-711 South Korea Department of General Surgery Chungbuk National UniversityGaeshindong 62 Heungdukgu Cheongju 361-711 South Korea Department of Pathology College of Medicine Chungbuk National UniversityGaeshindong 62 Heungdukgu Cheongju 361-711 South Korea

We report a rare case of a 74-year-old man with metachronous gallbladder cancer and bile duct cancer who underwent curative resection twice, with the operations nine years apart. At the age of 65 years, the patient underwent a cholecystectomy and resection of the liver bed for gallbladder cancer. This was a welldifferentiated adenocarcinoma, with negative resection margins （T2NOM0, stage Ⅰ B）. Nine years later, during a follow-up examination, abdominal computed tomography and MRCP showed an enhanced 1.7 cm mass in the hilum that extended to the second branch of the right intrahepatic bile duct. We diagnosed this lesion as a perihilar bile duct cancer, Bismuth type Ⅲ a, and performed bile duct excision, right hepatic Iobectomy and Roux-en-Y hepaticojejunostomy. The histological diagnosis was a well-differentiated adenocarcinoma with one regional lymph node metastasis （TINIM0, stage Ⅱ B）. Twelve months after the second operation, the patient is well, with no signs of recurrence. This case is compared with 11 other cases of metachronous biliary tract cancer published in the world medical literature.

关键词： Biliary tree Metachronous double cancer Gallbladder cancer Hilar bile duct cancer

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Roles of humidity and heat treatment temperatures on YBa_2Cu_3O_(7-x) coated conductors by trifluoroacetic acid-metal organic deposition process

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中国有色金属学会会刊：英文版 2009年第4期19卷 956-960页

作者： Seok-Hern JANG Jun-hyung LIM Chang-Min LEE Eui-Cheol PARK Soo-Min HWANG Jun-Hyuk choi Jong-hyun SHIM jin-hyun PARK Won KIM jinho JOO School of Advanced Materials Science and Engineering Sungkyunkwan University

YBa2Cu3O7-x(YBCO) films were fabricated on an LAO substrate using the trifluoroacetic acid-metal organic deposition(TFA-MOD) method and the effects of the humidity and heat treatment temperatures on the microstructure,degree of texture and critical properties of the films were *** order to understand the combined effects of the humidity and the calcining and firing temperatures on critical properties,heat-treatment was performed at various temperatures with the other processing variables *** films were calcined at 400-430 ℃ and fired at 750-800 ℃ in a 0-12.1% humidified Ar-O2 *** texture was determined by pole-figure *** amount of the BaF2 phase was effectively reduced and a sharp and strong biaxial texture was formed under a humidified atmosphere,which led to increased critical *** addition,the microstructure varied significantly with firing temperature but changed little with calcining *** highest IC of 40 A/cm-width,which corresponds to JC value of 1.8 MA/cm2,was obtained for the films fired at 775 ℃(in 12.1% humidity) after calcining at 400-430 ℃.It is likely that the highest IC value is due to the formation of a more pure YBCO phase,c-axis grains,and a denser microstructure.

关键词： YBa2Cu3O7 热处理温度三氟乙酸沉积过程湿度涂层导体有机金属微观结构变化

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Ethanol extract of Kalopanax septemlobus leaf inhibits HepG2 human hepatocellular carcinoma cell proliferation via inducing cell cycle arrest at G_1 phase

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Asian Pacific Journal of Tropical Medicine 2016年第4期9卷 336-342页

作者： Cheol Park Ji-Suk Jeong jin-Woo Jeong Sung Ok Kim Yong-Joo Kim Gi-Young Kim Su-hyun Hong Yung hyun choi Department of Molecular Biology College of Natural Sciences and Human EcologyDongeui University Department of Research and Development of Resources Gurye-gun Agricultural Center Wild Flower Institute.Gurye-gun Anti-Aging Research Center.Dongeui University Department of Food Science & Biotechnology College of EngineeringKyungsung University Republic of Korea Laboratory of Immunobiology.Department of Marine Life.Sciences.Jeju National University Department of Biochemistry.Dongeui University

Objective:To investigate the effects of an ethanol extract of Kalopanax septemlobus(Thunb.)***(EEKS) on cell proliferation in human hepatocellular carcinoma cells and its mechanisms of ***:Cells were treated with EEKS and subsequently analyzed for cell proliferation and flow cytometry *** of cell cycle regulators were determined by reverse transcriptase polymerase chain reaction analysis and Western blotting,and activation of eyclin-associaled kinases studied using kinase ***:The EEKS suppressed cell proliferation in both HepG2 and Hep3 B cells,but showed a more sensitive anli-proliferative activity in HepG2 *** cytometry analysis revealed an association between the growth inhibitory effect of EEKS and with G_1 phase cell cycle arrest in HepG2 cells,along with the dephosphorylation of retinoblastoma protein(pRB) and enhanced binding of pRB with the E2 F transcription factor family *** with EEKS also increased the expression of cyclin-dependent kinase(CDK) inhibitors,such as p21WAF1/CIP1 and *** any noticeable changes in G_1 cyclins and CDKs(except for a slight decrease in CDK4).Treatment of HepG2 cells with EEKS also increased the binding of p21 and p27 with CDK4 and *** was paralleled by a marked decrease in the cyclin D- and cyclin E-associated kinase ***:Overall,our findings suggest that EEKS may be an effective treatment for liver cancer through suppression of cancer cell proliferation via G_1,cell cycle arrest Further studies arc required to identify the active compounds in EEKS.

关键词： Kalopanax septemlobus Hepatocellular carcinoma G1 cell cycle arrest CDK inhibitor pRB

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Pravastatin activates the expression of farnesoid X receptor and liver X receptor alpha in Hep3B cells

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Hepatobiliary & Pancreatic Diseases International 2014年第1期13卷 65-73页

作者： hyun Woo Byun Eun Mi Hong Soo Hee Park Dong Hee Koh Min Ho choi hyun Joo Jang Sea Hyub Kae jin Lee Division of Gastroenterology Department of Internal Medicine Hallym University College of Medicine Dongtan Sacred Heart Hospital

BACKGROUND: Statins are suggested to preserve gallbladder function by suppressing pro-inflammatory cytokines and preventing cholesterol accumulation in gallbladder epithelial cells. They also affect cross-talk among the nuclear hormone receptors that regulate cholesterol-bile acid metabolism in the nuclei of hepatocytes. However, there is controversy over whether or how statins change the expression of peroxisome proliferator-activated receptor(PPAR)α, PPARγ, liver X receptor α(LXRα), farnesoid X receptor(FXR), ABCG5, ABCG8, and 7α-hydroxylase(CYP7A1) which are directly involved in the cholesterol saturation index in bile. METHODS: Human Hep3B cells were cultured on dishes. MTT assays were performed to determine the appropriate concentrations of reagents to be used. The protein expression of PPARα and PPARγ was measured by Western blotting analysis, and the mRNA expression of LXRα, FXR, ABCG5, ABCG8 and CYP7A1 was estimated by RT-PCR. RESULTS: In cultured Hep3B cells, pravastatin activated PPARα and PPARγ protein expression, induced stronger expression of PPARγ than that of PPARα, increased LXRα mRNA expression, activated ABCG5 and ABCG8 mRNA expression mediated by FXR as well as LXRα, enhanced FXR mRNA expression, and increased CYP7A1 mRNA expression mediated by the PPARγ and LXRα pathways, together or independently. CONCLUSION: Our data suggested that pravastatin prevents cholesterol gallstone diseases via the increase of FXR, LXRαand CYP7A1 in human hepatocytes.

关键词： pravastatin PPARγ liver X receptor α farnesoid X receptor gallstone disease

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A time-domain estimation method of rapidly time-varying channels for OFDM-based LTE-R systems

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Digital Communications and Networks 2019年第2期5卷 94-101页

作者： jin-Kyu choi Van Due Nguyen Hai Nam Nguyen Van Vinh Duong Tien Hoa Nguyen Hanbyeog Cho hyun-Kyun choi Seong-Gyoon Park Smart Mobility Research Department of ETR1 DaejeonSouth Korea School of Electronics and Telecommunicalions HUSTViet Nam Electronics and Telecommunications Research Institute DaejeonSouth Korea School of Information and Communication in KongJu National University South Korea

This paper addresses the performance of fast doubly selective fading channel estimation combined with InterCarrier Interference (ICI) cancellation for Long Term Evolution (LTE) communication platform in the High Speed Railway (HSR) environment. We consider the Channel Impulse Response (CIR) coefficients with a critical Doppler frequency shift and multi-path fading that were taken from the WINNER II channel model and the D2a propagation scenario, where the conditions of HSR are analyzed. As multi-path fading increases and the channel varies in the order of the symbol period, we first propose a novel approach for designing a pilot symbol structure in the time domain. Then, we describe the deployment of the proposed pilot symbol structure to estimate the channel in the time domain. Channel information corresponding to the data positions is obtained by linear interpolation. In each OFDM symbol, the slope and the initial value for establishing an interpolation function are estimated to adapt to the time variation of the channel. An accurate estimate of channel state information is used for the purpose of ICI cancellation. The simulation results show that the channel estimated by our proposed method can follow the real channel well, even in a very high Doppler frequency. The estimation method in terms of Mean Squared Error (MSE) significantly outperforms the state-of-the-art methods. The combination of our channel estimator with several interference cancelers provides a considerably better system performance than that achieved when frequency channel estimation is used.

关键词： ICI cancellation OFDM Channel estimation LTE-R

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