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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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Free Energy Level Correction by Monte Carlo Resampling with Weighted Histogram Analysis Method

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Chinese Journal of Chemical Physics 2020年第2期33卷 183-195,I0003,I0010-I0017页

作者： Seyoung Chung Sun Mi choi Wook Lee kwang hyun Cho Young Min Rhee Department of Chemistry Pohang University of Science and TechnologyPohang 37673Korea Department of Chemistry Korea Advanced Institute of Science and TechnologyDaejeon 34141Korea

Free energy calculations may provide vital information for studying various chemical and biological *** mechanical methods are required to accurately describe interaction energies,but their computations are often too demanding for conformational *** a remedy,level correction schemes that allow calculating high level free energies based on conformations from lower level simulations have been ***,we present a variation of a Monte Carlo(MC)resampling approach in relation to the weighted histogram analysis method(WHAM).We show that our scheme can generate free energy surfaces that can practically converge to the exact one with sufficient sampling,and that it treats cases with insufficient sampling in a more stable manner than the conventional WHAM-based level correction *** can also provide a guide for checking the uncertainty of the levelcorrected surface and a well-defined criterion for deciding the extent of smoothing on the free energy surface for its visual *** demonstrate these aspects by obtaining the free energy maps associated with the alanine dipeptide and proton transfer network of the KillerRed protein in explicit water,and exemplify that the MC resampled WHAM scheme can be a practical tool for producing free energy surfaces of realistic systems.

关键词： Free energy level correction Weighted histogram analysis method Monte Carlo resampling

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Changes of the intestinal endocrine cells in the C57BL/6 mouse after implantation of murine lung carcinoma (3LL): An immunohistochemical quantitative study

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World Journal of Gastroenterology 2005年第35期11卷 5460-5467页

作者： Sae-kwang Ku Seung-Kyoo Seong Dae-Young Kim Hyeung-Sik Lee Jong-Dae Kim Hae-Yun choi Bu-Il Seo Jae-hyun Lee Pharmacology and Toxicology Laboratory Central Research Laboratories Dong-Wha Pharmaceutical Industrial Co Ltd Anyang 430-017 Republic of Korea Developmental Biology/Embryology Division of Biological Science Gachon Medical School Kanghwha 417-840 Republic of Korea Department of Herbal Biotechnology Daegu Haany University Gyeongsan 712-715 Republic of Korea College of Oriental Medicine Daegu Haany University Gyeongsan 712-715 Republic of Korea Laboratory of Histology College of Veterinary Medicine Kyungpook National University Taegu 702-701 Republic of Korea

AIM: To study the distributions and frequencies of intestinal endocrine cells in the C57BL/6 mouse with immunohistochemical method using seven types of specific antisera against chromogranin A (CGA), serotonin,somatostatin, glucagons, gastrin, cholecystokinin (CCK)-8 and human pancreatic polypeptide (hPP) after abdominal subcutaneous implantation of murine lung carcinoma (3LL).METHODS: The experimental animals were divided into two groups, one is non-implanted Sham and the other is 3LL-implanted group. Samples were collected from six regions of intestinal tract at 28th d after implantation of 3LL cells (1×105 cell/mouse).RESULTS: In this study, five types of immunoreactive (IR) cells were identified except for gastrin and hPP. The regional distributions of the intestinal endocrine cells in the 3LL-implanted group were similar to those of the non-implanted Sham. However, significant decreases of IR cells were detected in 3LL-implanted group compared to those of non-implanted Sham. CGA- and serotonin-IR cells significantly decreased in 3LL-implanted groups compared to that of non-implanted Sham. Somatostatin-IR cells in the jejunum and ileum and CCK-8-IR cells in the jejunum of 3LL-implanted groups significantly decreased compared to that of non-implanted Sham. In addition,glucagon-IR cells were restricted to the ileum and colon of non-implanted ***: Implantation of tumor cell mass (3LL)induced severe quantifiable changes of intestinal endocrine cell density and the abnormality in density of intestinal endocrine cells may contribute to the development of gastrointestinal symptoms such as anorexia and indigestion, frequently encountered in patients with cancer.

关键词： Intestinal endocrine cell Immunohistochemistry C57BL/6 mouse 3LL Tumor

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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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Tenofovir rescue therapy for chronic hepatitis B patients after multiple treatment failures

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World Journal of Gastroenterology 2012年第47期18卷 6996-7002页

作者： Yu Jin Kim Dong hyun Sinn Geum-Youn Gwak Moon Seok choi kwang Cheol Koh Seung Woon Paik Byung Chul Yoo Joon Hyeok Lee Department of Medicine Samsung Medical CenterSungkyunkwan University School of MedicineSeoul 135-710South Korea

AIM:To evaluate the efficacy and safety of tenofovir disoproxil fumarate(TDF) for chronic hepatitis B(CHB) patients after multiple ***:A total of 29 CHB patients who had a suboptimal response or developed resistance to two or more previous nucleoside/nucleotide analogue(NA) treatments were *** subjects were treated with TDF alone(n = 13) or in combination with lamivudine(LAM,n = 12) or entecavir(ETV,n = 4) for ≥ 6 *** virologic response(CVR) was defined as an achievement of serum hepatitis B virus(HBV) DNA level ≤ 60 IU/mL by real-time polymerase chain reaction method during *** assessment was based on serum creatinine and phosphorus *** patients had histories of LAM and adefovir dipivoxil(ADV) treatment and 18 patients were exposed to LAM,ADV,and ***-seven patients(93.1%) were hepatitis B e antigen(HBeAg) positive and the mean value of the baseline serum HBV DNA level was 5.5 log IU/mL ± 1.7 log IU/*** median treatment duration was 16 mo(range 7 to 29 mo).RESULTS:All the patients had been treated with LAM and developed genotypic and phenotypic resistance to *** to ADV was present in 7 patients and 10 subjects had a resistance to *** patient had a resistance to both ADV and *** cumulative probabilities of CVR at 12 and 24 mo of TDF containing treatment regimen calculated by the Kaplan Meier method were 86.2% and 96.6%,*** one patient failed to achieve CVR,serum HBV DNA level decreased by 3.9 log IU/mL from the baseline and the last serum HBV DNA level during treatment was 85 IU/mL,achieving near *** patients in this study showed viral breakthrough or primary non-response during the follow-up *** cumulative probability of HBeAg clearance in the 27 HBeAg positive patients was 7.4%,12%,and 27% at 6,12,and 18 mo of treatment,*** efficacy of TDF containing regimen was not statistically different according to the presence of specific HBV mutatio

关键词： Tenofovir Chronic hepatitis B Treatment failure

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Effects of oxygen concentration and flow rate on cognitive ability and physiological responses in the elderly

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Neural Regeneration Research 2013年第3期8卷 264-269页

作者： hyun-Jun Kim hyun-Kyung Park Dae-Woon Lim Mi-hyun choi hyun-Joo Kim In-Hwa Lee hyung-Sik Kim Jin-Seung choi Gye-Rae Tack Soon-Cheol Chung Department of Obstetrics & Gynecology Konkuk University Department of Laboratory Medicine Seoul Clinical Laboratories Department of Information & Communication Engineering Dongguk University Department of Biomedical Engineering Research Institute of Biomedical EngineeringCollege of Biomedical & Health ScienceKonkuk University

The supply of highly concentrated oxygen positively affects cognitive processing in normal young adults. However, there have been few reports on changes in cognitive ability in elderly subjects following highly concentrated oxygen administration. This study investigated changes in cognitive ability, blood oxygen saturation （%）, and heart rate （beats/min） in normal elderly subjects at three different levels of oxygen [21% （1 L/min）, 93% （1 L/min）, and 93% （5 L/min）] administered during a 1-back task. Eight elderly male （75.3 ＋ 4.3 years old） and 10 female （71.1 ＋ 3.9 years old） subjects, who were normal in cognitive ability as shown by a score of more than 24 points in the Mini-Mental State Examination-Korea, participated in the experiment. The experiment consisted of an adaptation phase after the start of oxygen administration （3 minutes）, a control phase to obtain stable baseline measurements of heart rate and blood oxygen saturation before the task （2 minutes） and a task phase during which the 1-back task was performed （2 minutes）. Three levels of oxygen were administered throughout the three phases （7 minutes）. Blood oxygen saturation and heart rate were measured during each phase. Our results show that blood oxygen saturation increased, heart rate decreased, and response time in the 1-back task decreased as the concentration and amount of administered oxygen increased. This shows that administration of sufficient oxygen for optimal cognitive functioning increases blood oxygen saturation and decreases heart rate.

关键词： neural regeneration clinical practice highly concentrated oxygen cognitive task 1-back task cognitive ability blood oxygen saturation heart rate physiological responses elderly grant-supported paper neuroregeneration

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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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Computational design of Mg alloys with minimal galvanic corrosion

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Journal of Magnesium and Alloys 2022年第7期10卷 1972-1980页

作者： Krishnamohan Thekkepat hyung-Seop Han Ji-Won choi Seung-Cheol Lee Eul Sik Yoon Guangzhe Li hyun-kwang Seok Yu-Chan Kim Jae-Hun Kim Pil-Ryung Cha Indo-Korea Science and Technology Center JakkurBangalore 560065India Division of Nano&Information Technology KIST SchoolKorea University of Science and TechnologySeoul 02792Republic of Korea Electronic Materials Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Center for Biomaterials Biomedical Research InstituteKorea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Plastic and Reconstructive Surgery Korea University College of MedicineSeoul 02841Republic of Korea Division of Bio-Medical Science and Technology KIST SchoolKorea University of Science and TechnologySeoul 02792Republic of Korea School of Advanced Materials Engineering Kookmin UniversitySeoul 02707Republic of Korea

Formation of galvanic cells between constituent phases is largely responsible for corrosion in Mg-based *** develop a methodology to calculate the electrochemical potentials of intermetallic compounds and alloys using a simple model based on the Born-Haber *** electrochemical potentials are used to predict and control the formation of galvanic cells and minimize *** demonstrate the applicability of our model by minimizing galvanic corrosion in Mg-3wt%Sr-x Zn alloy by tailoring the Zn *** methodology proposed in this work is applicable for any general alloy system and will facilitate efficient design of corrosion resistant alloys.

关键词： Galvanic corrosion First-principles Cluster expansion Thermodynamics Modeling Magnesium alloys

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Heat Transfer between Casting and Die during High Pressure Die Casting Process of AM50 Alloy-Modeling and Experimental Results

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Journal of Materials Science & Technology 2008年第1期24卷 131-135页

作者： Zhipeng GUO Shoumei XIONG Sang-hyun Cho Jeong-Kil choi Key Laboratory for Advanced Manufacturing by Materials Processing Technology Department of Mechanical Engineering Tsinghua University Beijing 100084 China Advanced Material R＆D Center Korean Institute of Industrial Technology 994-32 Dongchun-Dong Yonsu-Ku Inchon Korea

A method based on die casting experiments and mathematic modeling is presented for the determination of the heat flow density （HFD） and interfacial heat transfer coefficient （IHTC） during the high pressure die casting （HPDC） *** were carried out using step shape casting and a commercial magnesium alloy,*** profiles were measured and recorded using thermocouples embedded inside the die. Based on these temperature readings,the HFD and IHTC were successfully determined and the calculation results show that the HFD and IHTC at the metal-die interface increases sharply right after the fast phase injection process until approaching their maximum values,after which their values decrease to a much lower level until the dies are *** patterns of heat transfer behavior were found between the die and the casting at different *** thinner the casting was,the more quickly the HFD and IHTC reached their steady ***,the values for both the HFD and IHTC values were different between die and casting at different thicknesses.

关键词： : Interfacial heat transfer coefficient High pressure die casting process AM50 Magnesium alloy

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Noble strain of Sparassis latifolia produces high content of β-glucan

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Asian Pacific Journal of Tropical Biomedicine 2015年第8期5卷 615-621页

作者： Dong Ju Lee Min Cheol Jang A Ra Jo hyun Jun choi kwang-Sang Kim Youn-Tae Chi School of Biological Sciences and Technology Chonnam National University Higher Education Center for Bioregulator Research Chonnam National University Jangheung Research Institute for Mushroom Industry 288 Woodland-gil Anyang-myun Jangheung-gun Jeollanam-do 529-851Republic of Korea

Objective: To classify four new Sparassis strains(CLM1, CKM1, CKM2, and KJM1) using the internal transcribed spacer sequence and to elucidate their β-glucan content and mycelial ***: Two different microbiological media were used to determine growth rate. The β-glucan contents were analyzed using the Megazyme Mushroom and Yeast Beta-Glucan kit. To determine the genetic relationships, phylogenetic trees were constructed using ClustalX. Multiple sequence alignments were printed and shaded with the BOXSHADE 3.21 program. Results: In this study, four new Sparassis strains were isolated from the southern region of the Korea Peninsula. They were all classified into the Sparassis latifolia clade as a monophyletic group based on the internal transcribed spacer sequence. Mycelial growth rate of the CLM1 strain was highest in potato dextrose agar and potato dextrose agar larch. The β-glucan content of the CLM1 strain was highest at 29.5%(w/w). A high degree of sequence divergence was detected in the RNA polymerase second largest subunit II gene(RPB2) within Sparassis spp. tested. The putative amino acid sequences of the RPB2 had a distinct sequence. The nucleotide sequences of the RPB2's intron were also divergent among Sparassis spp., even though their nucleotide length was well conserved within Sparassis latifolia. Conclusions: These results indicate that the nucleotide sequences and the amino acid sequences of RPB2 can be used to identify individual Sparassis sp. The Sparassis strain CLM1 may be best for developing a remedy to prevent or treat cancer and other chronic diseases.

关键词： Divergence β-Glucan Intron RNA polymerase second largest subunit II gene Sparassis

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