• Title/Summary/Keyword: Silver

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Comparison of the Effects of Nano-silver Antibacterial Coatings and Silver Ions on Zebrafish Embryogenesis

  • Yeo, Min-Kyeong;Yoon, Jae-Won
    • Molecular & Cellular Toxicology
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    • v.5 no.1
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    • pp.23-31
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    • 2009
  • To compare the effects of nanometer-sized silver ions and support materials (nano-silver coating material, NM-silver) and silver ions, we exposed zebrafish embryos to both types of nano-silver ions and compared the acute responses during embryogenesis. The amount of silver in the NM-silver (17.16%) was greater than that in the silver ion (4.56%). Both of these materials have different atomic compositions. The silver ion-exposed groups (10 and 20 ppt) showed lower survival rates than the NM-silver-exposed groups (10 and 20 ppt). NM-silver penetrated the skin and blood tube of zebrafish larvae as aggregated particles, whereas, silver ions penetrated the organelles, nucleus and yolk in a spread-out pattern. Micro-array analysis of RNA from zebrafish larvae (72 hours post-fertilization) that were treated with either NM-silver or silver ions, showed alteration in expression of the BMP, activin, TGF-$\beta$, and $GSK3{\beta}$ genes pathway. Additionally, $GSK3{\beta}$ gene pathway for apoptosis that was related with left-right asymmetry. Gene expression changes in the NM-silver or silver ions-treated zebrafish embryo led to phenotypic changes in the hatched larvae, reflecting increased apoptosis and incomplete formation of an axis.

Assessment of Bacteria Removal Using Silver Ion Absorbed Ceramic Filter

  • Kim, Woo-Hang;Smith, James
    • Journal of Environmental Science International
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    • v.21 no.8
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    • pp.901-907
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    • 2012
  • The objective of this study was to evaluate bacteria removal ability of the metallic silver which was baked silver ion impregnated ceramic filter at heating condition. Silver leaking from baked ceramic filter was tested to sustain bacteria removal for a long time. Silver impregnated ceramic filter could remove E. coli completely at $10^{12}$ MPN/100ml to $10^{13}$ MPN/100ml of influent. However, ceramic filter without silver did not remove E. coli completely under the same condition. After baking, the silver impregnated ceramic filter almost didn't leak out the silver ion from filter. Photo of TEM (Transmission Electron Microscopy) showed that absorbed silver ions remained in ceramic filter after baking process and most of silver were less than 10 nm. According to the increase in the amount of silver in the ceramic filter, removal efficiencies of E. coli were increased but turbidity removal was decreased. It can be accounted that increased removal efficiency of E. coli was from disinfection of silver that is in the ceramic filter. Simulated concentrations of bacteria agree well with the observed experimental effluent concentration data. Moreover, first-order decay coefficients increased to 0.0034/min after silver was added in the ceramic filter. Increase of first-order decay coefficient proves that silver-added ceramic filter can remove bacteria easily.

Exploring Silver ICT Convergent Typology and ICT Contribution Value (실버산업의 ICT 융합 유형과 ICT 기여 가치 탐색)

  • Han, Hyun-Soo;Kang, Tae-Wook
    • Korean Management Science Review
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    • v.34 no.1
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    • pp.57-70
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    • 2017
  • The phenomenon of increasing aging population is one of the crucial social and economic issues in these day. In this paper, drawn from the industrial application cases and relevant literatures, we present the typology of ICT convergent applications targeted for silver generation, referred as silver ICT. Subsequently, the contributional value of ICT as the enabling technology is estimated. We firstly conduct keyword search to collect currently used silver ICT applications. Secondly, drawn from the social welfare literature, we organize distinctive needs of the silver generations. Then, on the basis of task technology fit framework, typology of ICT enabled silver applications is organized through the fit of ICT in the sense of fulfilling those silver needs. Finally, using the industry input-output table figures, potential ICT contributions for silver ICT are estimated. The proposed silver ICT typology and ICT contributions provides useful insights for further research in the area of ICT convergence and silver market research.

Facile Synthesis of Silver Chloride Nanocubes and Their Derivatives

  • Kim, Seung-Wook;Chung, Haeg-Eun;Kwon, Jong-Hwa;Yoon, Ho-Gyu;Kim, Woong
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2918-2922
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    • 2010
  • We demonstrate a facile route to synthesize silver chloride nanocubes and derivative nanomaterials. For the synthesis of silver chloride nanocubes, silver nitrate and hydrochloric acid were used as precursors in ethylene glycol, and poly (vinyl pyrrolidone) as a surfactant. Molar ratio of the two precursors greatly influenced the morphology and composition of the final products. As-synthesized silver chloride nanocubes showed size-dependent optical properties in the visible region of light, which is likely due to a small amount of silver clusters formed on the surface of silver chloride nanocubes. Moreover, we show for the first time that simple reduction of silver chloride nanocubes with different reducing reagents leads to the formation of delicate nanostructures such as cube-shaped silver-nanoparticle aggregates, and silver chloride nanocubes with truncated corners and with silver-nanograin decorated corners. Additionally, we quantitatively investigated for the first time the evolution of silver chloride nanocubes to silver chloride nanocubes decorated with silver nanoparticles upon exposure to e-beam. Our novel and facile synthesis of silver chloride related nanoparticles with delicately controlled morphologies could be an important basis for fabricating efficient photocatalysts and antibacterial materials.

A Study on the Feasibility of a Cyanide-Free Silver Plating Bath (비시안 은도금욕의 가능성에 관한 연구)

  • 이상화
    • Journal of the Korean institute of surface engineering
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    • v.29 no.2
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    • pp.140-145
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    • 1996
  • Silver deposits formed on copper substrates by replacement reactions show poor adhesion, and a silver film plated on such a deposit does not adhere. Silver ion makes a highly stable complex with cyanide ion, so that in a silver cyanide solution, the activity of silver ion is very small. This is one of the reasons for the universal use of cyanide baths in the industrial silver plating. However, the consideration of the difference between the values of the stability constants for bath the silver-iodide complex and the copper-iodide complex suggest that the rate of replacement deposition of silver on the copper substrate in si]ver-potassium iodide solution, could be comparatively low. To confirm this, the rate of replacement deposition of silver in both a silver-potassium iodide solution ($AgNO_3$0.10 mol/L, KI 2.00 mol/L ) and a strike silver plating bath (AgCN 0.028 mol/L, KCN 1.15 mol/L ) was estimated from the current density corresponding to the point of intersection of the anodic and the cathodic polarization curves. These estimated values were almost the same, and it is suggested that the silver-potassium iodide solution is not only a cyanide free silver plating bath capable of employing a copper substrate but a silver plating bath which requires no strike plating.

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SERS Study of Fluorescein Using the Silver Sol and Silver Mirror Substrates (Silver Sol과 Silver Mirror Substrate를 이용한 Fluorescein의 SERS 연구)

  • Lee, Chul-Jae;Choi, Hyun-Kuk;Jung, Maeng-Joon
    • Journal of the Korean Society of Industry Convergence
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    • v.10 no.1
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    • pp.27-32
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    • 2007
  • It has been recently reported that the SERS (Surface Enhanced Raman Scattering) effect of the silver mirror substrate made by Tollen's method is much superior to that of other substrates. In this study, the experiments for comparison of surface enhancement of silver sol and silver mirror substrates were done, where we checked the characteristics of silver mirror substrate made by Tollen's method. The surface enhancement of fluorescein was analyzed by silver sol and silver mirror substrates. We observed the SERS spectra of fluorescein. The assignments of the vibrational bands shown in SERS spectra are given based on both literature and the semi-empirical calculations at the PM3 methods. The surface enhancement properties for fluorescein showed that the silver mirror was more superior to sliver sol substrates. Spectra of fluorescein revealed that fluorescein was adsorbed on silver surfaces by a common oxygen atom. According to the 'surface selection rule', the vibrations in the band intensities reflect the adsorption orientation of the molecule on to the surface of SERS substrates. Therefore, we deduced that the adsorption orientation of fluorescein was little tilted perpendicular to the silver surfaces by using of the surface selection rules.

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STUDY OF STABILITY AND EFFECT OF COLLOIDAL SILVER IN VARIOUS EMULSIONS (Colloidal Silver Emulsion에서 안정성과 효능, 효과에 관한연구)

  • 지홍근;윤경로
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.24 no.1
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    • pp.48-73
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    • 1998
  • Colloid refers to dispersed particles of solid or liquid having diameters of $10^{-5}$ to $10^{-7}$cm, among which colloidal silver is produced by electrolysis. Colloidal silver of various concentrations according to charge and time were formed, antimicrobial activity of colloidal silver was measured. And, the optimum conditions for emulsion were determined by changing the concentration of coloidal silver. Also, the stability of the emulsion was measured by zeta potential and chroma meter by applying colloidal silver to creams(W/S, O/W, MLV)

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Silver Ore and Floatation Products from the Bupyeong Mine (부평광산(富平鑛山)의 금광석(金鑛石)과 선광산물(選鑛産物))

  • Park, Hee-ln;Park, No Young;Suh, Kyu Shik
    • Economic and Environmental Geology
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    • v.19 no.2
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    • pp.85-96
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    • 1986
  • The Bupyeong Silver mine which is located approximately 35km west of Seoul is currently the leading silver producer in Korea. The deposits occur as stockwork deposits hosted in Jurassic pyroclastic rocks. Occurrences of ore deposits and mineral paragenesis suggest a division of mineralization into four stages: Stage I, deposition of iron oxide and base metal sulfides; Stage II, deposition of tin oxide and silverm inerals; stage III, deposition of native silver and other silver minerals; Stage IV, formation of pyrite bearing siderite veinlets, Silver minerals in ore are native silver, argentite, freibergite, pyrargyrite, canfieldite, polybasite, dyscrasite and Ag-Fe-S mineral. The most important silver mineral is native silver among them. Chemical composition of important silver minerals were determined by electron probe microanalyser. Assay, size and modal analyses for floatation products were carried out. In floatation products, relative proportion of native silver for total important silver minerals have following ranges: feed, 64.7 to 74.74 wt.%; A-cleaner concentrate, 80.58 to 98.79 wt.%; and final tailing, 28.12 to 72. 57 wt. %. Average degree of liberation for native silver in feed and A-cleaner concentrate are 60.49% and 77.57% respectively. Negative relationship can be recognized between native silver and argentite in their abundance and behavior in floatation precesses.

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Classification of Silver Farming Types and Investigation of Proper Crop for Silver Farmers (실버농업의 유형분류 및 적합작목 탐색)

  • Kang, Kyeong-Ha;Yoon, Soon-Duck;Kang, Jin-Ku
    • Journal of Agricultural Extension & Community Development
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    • v.14 no.2
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    • pp.301-328
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    • 2007
  • The purposes of this study were to classify the silver farming types and to investigate proper crops for silver farmers. Data were collected from 408 farmers returned from the urban area. Descriptive statistics were employed using SPSS/PC windows program. After then, researchers discussed the silver farming patterns and their proper crops, and tried to analyze the silver farming model. Major results were as follows: The farming aims of retirees, urban residents as well as farmers returned from the urban area were various from hobby/ leisure to income generating activities. Fourteen types of silver farming were classified by farming aim and residential area of retirees. Retirees in the hobby/leisure-oriented silver farming type can select and enjoy the various plants, animals, and insects as well as crops due to their small scale. Silver farmers in the self-sufficiency type may select crops for their food. Income-oriented silver farmers may have difficulties in choosing the proper crop. They must consider their income needs, health status and field location. Profit-oriented silver farmers with venture mind can have some business opportunities in the agricultural sectors in spite of severe competition. As the aged silver farmers have poor health, they must keep work safety rules, use the proper work-aids, and utilize the labor-saving farming system.

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A Survey on the Housing Preferences of Elderly People (실버타운 선호도에 영향을 주는 요인에 관한 연구)

  • Moon, Ja
    • Journal of Korean Academy of Rural Health Nursing
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    • v.2 no.2
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    • pp.111-119
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    • 2007
  • Purpose: In this study consumers' preference for housing for elderly people was analyzed as well as the recognition by elders of silver town facilities, and their preference for service provided by silver town. The study was done to provide basic data for the development of silver town facilities that are low in cost and high in efficiency. Methods: A sample research was used in this study to analyze the understanding of old age, silver town, and service preference. Results: First, interest and intention to live in silver town was very positive, however low cost was also preferred and that is quite different to current silver towns of Korea. Second, women have more understanding of, requests for, and intention to move into silver town facilities than men. Women's demands for silver town facilities must be reflected in the development strategy of silver towns. Third, the most important part of activating silver town facilities is price strategy. Government political support is required in order to keep silver town move-in costs affordable. Fourth, silver towns must function as total service complex towns. Conclusion: This study is meaningful as efficient operation of silver town is suggested rather than facility degradation to achieve price reduction. This result is important to the development of silver towns based on consumer preference, as it suggests a development direction that is focused on securing differentiated services and programs.