• Title/Summary/Keyword: Ag/AgCl

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Somatic Embryogenesis and Plant Regeneration from Immature Zygotic Embryo Culture in Pepper (Capsicum annuum L.)

  • Jo, Jeong-Yon;Choi, Eun-Young;Choi, Dong-Su;Lee, Kwang-Woong
    • Journal of Plant Biology
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    • v.39 no.2
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    • pp.127-135
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    • 1996
  • An efficient system of somatic embryogenesis was established for the red pepper plant (Capsicum annuum L. cv. Nokkwang) usign immature zygotic embryos. The size of the immature zygotic embryos and the concentrations of 2, 4-D and sucrose were found to be critical. Somatic embryos were induced via callus or directly from explants and regenerated into plantlets successfully. When zygotic embryos 1~2 mm long were cultured on the modified Murashige-Skoong (MS) medium supplemented with 2 mg/L 2, 4-D for 3 weeks in the dark, somatic embryos were induced directly from the apical region of zygotic embryos with the highest frequency being approximately 90%. To mature the somatic embryos, ABA and an ethylene inhibitor AgNO3 were used. The highest frequency of shoot regeneration (25% in each) resulted at 2$\mu$M ABA or 20$\mu$M AgNO3 treatment at rates 3.7 and 1.6 times control, respectively. Shoots developed mainly from the cotyledonary node on CoCl2-containing medium, and from the upper side of cotyledon on medium containing AgNO3 while the embryos on the control medium produced shoots from both the cotyledonary node and the upper region of cotyledons both at frequencies of 50%. Indirect somatic embryogenesis via callus was induced at an efficiency of approximately 10% with zygotic embryos 3~4 mm long cultured on MS medium containing 5~10 mg/L, 2, 4-D for 5~7 weeks under a continuous light condition. The plants regenerated from the somatic embryos were morphologically normal. Using scanning electron microscopy, the direct and indirect somatic embryogeneses were observed to follow the globular, heart and torpedo stages, similar to zygotic embryogenesis. Also, suspensors appeared in the early globular and ovoid-shaped late globular embryos during indirect somatic embryogenesis.

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Fabrication and Characterization of Porous Silicon-based Urea Sensor Syst (다공질 실리콘을 이용한 요소검출용 바이오 센서 제작)

  • Jin, Joon-Hyung;Kang, Chul-Goo;Kang, Moon-Sik;Song, Min-Jung;Min, Nam-Ki;Hong, Seok-In
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.2003-2005
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    • 2002
  • 바이오 마이크로 시스템 및 바이오 MEMS 분야, 특히 실리콘을 기질로 하는 바이오 센서 제작에서 반도체 공정 기술은 센서의 대량 생산과 초소형화를 위해서 반드시 필요한 기술이다. 그러나, 감지전극의 마이크로화에 따른 센서의 감도 및 안정성 저하 문제는 해결해야 할 과제이다. 최근, 다공질 실리콘이 갖는 대면적이 실리콘 기질과 생체 고분자 (예: 단백질, 핵산 등) 간의 결합력을 향상시킬 수 있음이 알려지면서, 바이오 센서 분야에서, 새로운 형태의 드랜스듀서 재료로서의 다공질 실리콘에 대한 논의가 활발히 전개되고 있으며 또한, ISFET (Ion-Selective Field-Effect Transistors) 와는 달리 다공질 실리콘 층은 저항이 크기 때문에 센서 제작 과정에서의 부가적인 절연막을 필요로 하지 않는다. 본 연구에서는, 백금을 증착한 다공질 실리콘 표면에 전도성 고분자로서 Polypyrrole (PPy) 필름과 생체 고분자 물질로서 Urease를 각각 전기화학적으로 흡착하였다. 다공질 실리콘 층의 형성을 위해 테플론 소재의 전기화학 전지에 불산 (49%), 에탄올 (95%), $H_2O$ 혼합 용액을 넣고 실리콘 웨이퍼에 일정시간 수 mA의 산화 전류를 흘려주었으며, 약 $200{\AA}$의 티타늄 박막과 $200{\AA}$의 백금 박막을 RF 스퍼터링하여 작업 전극을 제작하였고, 백금 박막 및 Ag를 기화 증착하여 제작한 Ag/AgCl 박막을 각각 상대 전극과 기준전극으로 하였다. 박막 전극의 표면 분석을 위해 SEM (Scanning Electron Microscopy), EDX (Energy Dispersive X-ray spectroscopy) 등을 이용하였다. 제작된 요소 센서로부터 요소 농도 범위 0.01 mmol/L ${\sim}$ 100 mmol/L에서 약 0.2 mA/decade의 감도를 얻었다.

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Gold-Silver Mineralization of the Euiseong Area (의성지역(義城地域)의 금(金)-은(銀) 광화작용(鑛化作用))

  • Chi, Se-Jung;Choi, Seon-Gyu;Doh, Seong-Jae;Koh, Yong-Kwon
    • Economic and Environmental Geology
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    • v.24 no.2
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    • pp.151-165
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    • 1991
  • The Au-Ag deposits of the Euiseong area occurred in quartz veins which filled fissures in Cretaceous sedimentary and volcanic rocks. These ore veins can be classified in two types of deposits based on metallic mineral assemblages as follow: a pyrite type gold-silver deposit (Hoedong mine), characterized by Cu sulfides with Au-Ag alloy, and a Sb-rich silver deposit (Keumdongdo mine), characterized by base metal with Ag-bearing sulfosalts. Mineralogic and fluid inclusion evidences suggest that the ore minerals of these deposits was deposited from initial high temperatures (near $350^{\circ}C$) to later lower temperatures ($200^{\circ}C$) with moderate salinity fluids ranging from 5.8 to 3.8 eq. wt. % NaCl. The gold-silver mineralization of the Hoedong mine occurred at temperatures between 300 and $200^{\circ}C$ from fluids with log $f_{s_2}$ of -10 ~ -16 atm. The antimony - silver mineralization of the Keumdongdo mine were deposited at the higher temperatures (350 to $250^{\circ}C$) and $f_{S_2}$ (-10 ~ -13 atm) than gold mineralization of the Hoedong mine. The calculated log f02 of fluids at $250^{\circ}C$ in two deposits are -32 to -34 atm and -36.5 to -38.5 atm, respectively. Boiling evidences indicate that the ore mineralization of the Hoedong mine occurred at more shallow depth (0.5km) than that (1km) of the Keumdongdo mine. The above differences of depositional environments between two deposits caused the compositional changes of ore minerals such as electrum and sphalerite.

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Impacts of post-mortem ageing prior to freezing on technological and oxidative properties of coarse ground lamb sausage in a model system

  • Choe, Juhui;Kim, Hyun-Wook;Farouk, Mustafa M.;Kim, Yuan H. Brad
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.7
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    • pp.1021-1028
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    • 2017
  • Objective: The objective of this study was to evaluate the effects of ageing time of lamb loins prior to freezing on technological characteristics and oxidation stability of coarse ground lamb loin sausage using in a model system. Methods: Lamb loins (M. longissimus lumborum, n = 25) were aged at $-1.5^{\circ}C$ for 0, 1, 2, 3, and 8 wk and then frozen for the remaining days (a total of 30 wk). The aged/frozen/thawed lamb loins were ground, and model sausages were formulated with 75% aged/frozen/thawed lamb loin, 25% water, 1.5% sodium chloride (NaCl) and 0.3% sodium tripolyphosphate. The pH and thaw/purge loss of aged/frozen/thawed lamb loins were evaluated, and protein functionality (protein solubility and emulsifying capacity), water-holding capacity and textural properties of model sausages were determined. Cooked model sausages were vacuum-packaged in a plastic bag and displayed under continuous fluorescent natural white light ($3^{\circ}C{\pm}1^{\circ}C$). Colour and lipid oxidation of the cooked model sausages were evaluated on 0 and 21 d of display storage. Results: Ageing prior to freezing had no impact on pH and purge/thaw loss of lamb loins and the colour of cooked sausages (p>0.05) made from the loins. Lamb loins aged for at least 3 wk prior to freezing numerically improved total and myofibrillar protein solubilities (p>0.05) and emulsion activity index (p = 0.009) of meat batter, but decreased cooking loss (p = 0.003) and lipid oxidation (p<0.05) of model sausages. Conclusion: This study suggests that post-mortem ageing of raw meat prior to freezing could improve water-holding capacity and lipid oxidative stability of sausage made from the meat.

Detection of Foreign Antigen-specific $CD4^+Foxp3^+$ Regulatory T Cells by MHC Class II Tetramer and Intracellular CD154 Staining

  • Choi, Jin Young;Eo, Seong Kug
    • IMMUNE NETWORK
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    • v.13 no.6
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    • pp.264-274
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    • 2013
  • The unrestricted population of $CD4^+Foxp3^+$ regulatory T (Treg) cells, which have been known to control the expression of autoimmune diseases and protective immunity to inflammatory reactions, has led to greater appreciation of functional plasticity. Detecting and/or isolating Ag-specific $CD4^+Foxp3^+$ Tregs at the single cell level are required to study their function and plasticity. In this study, we established and compared both MHC class II tetramer and intracellular CD154 staining, in order to detect $CD4^+Foxp3^+$ Treg specific for foreign Ag in acute and chronic infections with lymphocytic choriomeningitis virus (LCMV). Our results revealed that MHC class II tetramer staining showed a lower detection rate of LCMV $GP_{66-77}$-specific $CD4^+$ T cells because most of MHC class II tetramers were unbound and unstable when combined staining was performed with intracellular cytokines. In contrast, intracellular CD154 staining was revealed to be easier and simple for detecting LCMV $GP_{66-77}$-specific $CD4^+$ T cells, compared to MHC class II tetramer staining. Subsequently, we employed intracellular CD154 staining to detect LCMV $GP_{66-77}$-specific $CD4^+Foxp3^+$ Tregs using $Foxp3^{GFP}$ knock-in mouse, and found that LCMV $GP_{66-77}$-specific $CD4^+Foxp3^+$ Tregs and polyclonal $CD4^+Foxp3^+$ Tregs showed differential expansion in mice infected with LCMV Arms or Cl13 at acute (8 and 13 days pi) and chronic phases (35 days pi). Therefore, our results provide insight into the valuable use of intracellular CD154 staining to detect and characterize foreign Ag-specific $CD4^+Foxp3^+$ Treg in various models.

Vasorelaxant Activities of Aqueous Extracts from Twenty Medicinal Plants Used in Oriental Medicines in Isolated Rat Aorta

  • Kim, Eun-Young;Lee, Kyung-Ok;Kim, Dong-Il;Rhyu, Mee-Ra
    • Preventive Nutrition and Food Science
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    • v.15 no.3
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    • pp.189-195
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    • 2010
  • Water extracts from 20 medicinal plants, traditionally used for postmenopausal symptoms in Korea, were examined for their vasorelaxant activity in isolated rat thoracic aorta rings precontracted with norepinephrine (NE). Among the 20 medicinal plants, Cornus officinalis (CoEx, 0.3 mg/mL), Schisandra chinensis (ScEx, 0.3 mg/mL), Erythrina variegate (EvEx, 0.3 mg/mL), and Epimedium koreanum (EkEx, 0.3 mg/mL) showed rapid relaxation of endothelium-intact aorta ($69\pm4%$, $40\pm3%$, $25\pm2%$, and $23\pm3%$ of active tone induced by NE, respectively). In contrast, the extracts of Erythrina variegata (EvEx), Angelica gigas (AgEx), Pueraria thunbergiana (PtEx), and EkEx lead to gradual (i.e., long-term) relaxation to baseline in endothelium-intact vessels. The time to complete relaxation was 20~40 min. These 6 plant extracts were selected for the investigation of possible underlying mechanisms. The CoEx-, ScEx-, or EkEx-induced rapid relaxations were virtually abolished by endothelium denudation, and were significantly inhibited by pretreatment with nitric oxide (NO) synthase inhibitor $N^G$-nitro-L-arginine (L-NNA, 10 ${\mu}M$), indicating that increased formation of NO might contribute to the endothelium-mediated relaxation. In long-term responses, the endothelium denudation did not affect PtEx-induced relaxation, whereas it delayed responses by EvEx and AgEx, and significantly inhibited the effect of EkEx. Among EvEx, AgEx, and PtEx, EvEx attenuated the $CaCl_2$-induced vasoconstriction in high-potassium depolarized medium, implying that EvEx is involved in inhibition of the extracellular calcium influx to smooth muscle through voltage dependent calcium channels. These results provide the scientific rationale for the interrelationships between the use of 20 medicinal plants and their effects on cardiovascular health in estrogen deficient conditions.

A Suitable Dichromate Reflux Method for the Analysis of Chlorous Wastewater (COD 분석시 염소이온의 간섭작용에 관한 연구)

  • 김종규;김남천;민달기
    • Journal of Environmental Health Sciences
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    • v.15 no.2
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    • pp.33-40
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    • 1989
  • Dichromate reflux method for COD analysis is one of the useful and precise way to solve the organic content of the wastewater. But the standard procedure for COD is not entirely satisfactory for sample containing appreciable amounts of inhibiting substance, especially chloride ion. Under the conditions of the established test, a big disadvantage of the method is that dichromate oxidizes chloride quantitatively to chlorine. When it is necessary to use silver sulfate as a catalyst in the COD procedure, chloride must be removed before the addition of the catalyst. Silver sulfate and mecuric sulfate forms a precipitate of AgCl and HgCl$_{2}$ separately which is not completely oxidized during the test and, therefore, cannot be corrected for. So, we evaluate and compensate the amount of chloride oxidation in the absence of chemicals during the experimental procedure. Calculation of COD is made using the following reviced formula: real COD = tested COD - 0.2277Cl.

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Transparent organic light-emitting devices with CsCl passivation layer

  • Kim, So-Youn;Lee, Chan-Jae;Ha, Mi-Young;Moon, Dae-gyu;Han, Jeong-In
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.683-686
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    • 2007
  • We have developed the transparent passivation layer for transparent organic light-emitting devices (TOLEDs) using CsCl layer. The CsCl passivation layer improves the optical transmittance of Ca/Ag double layer which have used as a semitransparent cathode, resulting in substantial increase of the luminance by the enhanced light extraction out of the cathode surface of the TOLEDs.

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PHOTOSENSITIVITY OF HETEROJUNCTION TYPE GRAINS IN CUBIC SILVER HALIDE MICROCRYSTALS

  • Park, In Yeong
    • Journal of Photoscience
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    • v.3 no.3
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    • pp.159-161
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    • 1996
  • Photosensitivity of silver halide emulsion depends on the properties of the microcrystals. Size, shape, grain distribution and chemical composition as well as the inner structure or the topography of the latent image specks affect on the optical properties and play an important role in the photographic process. In the present paper, a study on the sensitization of emulsion containing AgBrClI core/shell grains showed that for the given size, shape, halide content and crystal habit, under the optimal conditions the photosensitivity of the heterojunction type grains are different from that of the common regular grains. The optimal photosensitivity was obtained at the iodide content of 2.0 mo1%.

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Ore and Fluid Inclusions of the Tongyeong Gold-Silver Deposits (통영(統營) 금광상(金鑛床)의 광석(鑛石)과 유체포유물(流體包有物))

  • Park, Hee-In
    • Economic and Environmental Geology
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    • v.16 no.4
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    • pp.245-251
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    • 1983
  • The Tongyeong gold-silver deposits is located in Chungmu City, the southern end of Korean peninsula. The ore deposits is epithermal gold-silver vein emplaced in late Cretaceous andesite, andesitic pyroclastics and quartz porphyry. Ore is composed of pyrite, chalcopyrite, sphalerite, galena, electrum, argentian tetrahedrite, Cu-Ag-sulfides, quartz and rhodochrosite. Filling temperature of fluid inclusions in quartz ranges from 134 to $223^{\circ}C$ and salinity ranges from 1.2 to 3.8 weight % equivalent to NaCl.

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