• Title/Summary/Keyword: chemical indicator

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Hybridization by an Electrical Force and Electrochemical Genome Detection Using an Indicator-free DNA on a Microelectrode-array DNA Chip

  • Choi, Yong-Sung;Lee, Kyung-Sup;Park, Dae-Hee
    • Bulletin of the Korean Chemical Society
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    • v.26 no.3
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    • pp.379-383
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    • 2005
  • This research aims to develop DNA chip array without an indicator. We fabricated microelectrode array by photolithography technology. Several DNA probes were immobilized on an electrode. Then, indicator-free target DNA was hybridized by an electrical force and measured electrochemically. Cyclic-voltammograms (CVs) showed a difference between DNA probe and mismatched DNA in an anodic peak. Immobilization of probe DNA and hybridization of target DNA could be confirmed by fluorescent. This indicator-free DNA chip microarray resulted in the sequence-specific detection of the target DNA quantitatively ranging from $10^{-18}\;M\;to\;10^{-5}$ M in the buffer solution. This indicator-free DNA chip resulted in a sequence-specific detection of the target DNA.

The Predicton of the Shelf-life of Packaged Meals (Kim Pab) Marketed in Covenience Stores Using Simulation Study (모의실험을 통한 편의점 판매용 김밥 도시락의 유통기한 예측)

  • 곽동경;김성희
    • Journal of Food Hygiene and Safety
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    • v.11 no.3
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    • pp.189-196
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    • 1996
  • Based on microbiological-chemical test results under simulated time-temperature conditions, total plate count, coliform, and volatile basic nitrogen were selected as effective quality indicators for estimating probable shelf-life on Kim Pab dosirak marketed in convenience stores, and shelf-life at each storage temperature was calculated from regression equation between effective quality indicator standard limit and storage time. Estimated shelf lives of Kim Pab Dosirak were 17, 3 and 2 hours respectively under 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$. Because shelf-life was especially affected by intial values, regression analysis between initial effective quality indicator values and storage hours was performed for the estimation of probable shelf-life on Kim Pab during storage at 10, 20, or 3$0^{\circ}C$.

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Determination of the Dissociation Constant of Thymol Blue with Diode-Laser/Fiber-Optic Thermal Lensing Spectroscopy

  • 김성호;노영순
    • Bulletin of the Korean Chemical Society
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    • v.19 no.8
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    • pp.822-824
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    • 1998
  • The simple and convenient measurement of the dissociation constant of an indicator, thymol blue, was achieved by using a portable diode-laser/fiber-optic thermal lensing spectroscopy, which consisted of a visible diode laser, a photodiode, and an optical fiber. It gives comparable results to the cited value obtained from a conventional UV/VIS spectroscopy.

Insect natural enemies as bioindicators in rice paddies

  • Ueno, Takatoshi
    • Korean Journal of Agricultural Science
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    • v.39 no.4
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    • pp.545-553
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    • 2012
  • In Asia, including Japan and Korea, rice paddies occupy the largest cultivated area in agricultural land. Rice paddies provide the habitats for many organisms including endemic species, sustaining high biodiversity. Insect natural enemies inhabiting rice paddies have an important function for rice production as agents of 'ecosystem services' because they play a major role in suppressing rice pests. The diversity and abundance of natural enemies can be a good index reflecting the 'healthiness' of agro-ecosystem services in rice paddies. The present study investigates whether insect natural enemies could be good biological indicators for general arthropod biodiversity and agricultural practice. First, the concept of ideal bio-indicators was summarized. The strategy to explore and select such bio-indicators was then proposed. Lastly, field survey was made to evaluate the abundance and biodiversity of natural enemies in Japanese rice paddies where chemical inputs, i.e., insecticide use, were different. The results showed that reduction of chemical inputs led to an increase in species richness or diversity of natural enemies including parasitoids and predators. Then, the data were analyzed to examine suitable indicator species to assess environmental soundness of agricultural practice and biodiversity in rice paddies. The density of several species of natural enemies did respond both to pesticide use and to general arthropod biodiversity. The analyses thus have indicated that natural enemies can be suitable as bio-indicators. Usefulness of indicator species in rice paddies is discussed in the context of ecologically sound agriculture.

Development of Automatic Reading System for Steam Sterilization Indicator (스팀 멸균지시제 자동판독시스템 개발)

  • Song, Hyeok;Kim, Jeong-Rae;Lee, Woo-Cheol
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.4
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    • pp.709-714
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    • 2022
  • The color change of the success of the steam sterilization indicator used in steam sterilization is currently being read by relying on the human eye. The result of color change on the success of sterilization can only be accurately read and judged by trained personnel. Developed an automatic reading system for steam sterilization indicators for the current human-dependent system, and developed an automatic reading device system for reading methods that were previously relied on with the human eye to develop a system that is more accurate and easier for anyone to read.

pH Measurement Using Isosbestic Point of Indicator (지시약의 등흡광점을 이용한 용액의 pH 측정)

  • Won-Hyung Choi;Ho-Jang Hur
    • Journal of the Korean Chemical Society
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    • v.33 no.2
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    • pp.203-207
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    • 1989
  • The methyl red stock solution was added to sample solution and the absorbance values of this solution were measured at the maximum absorption wavelengths of the acidic form, the basic form, and the isosbestic point of the indicator. From the measurements of absorbance, the pH of this solution was calculated. The range of absorbance at the isosbestic point was maintained within 0.1 ${\sim}$ 0.3. The error of pH measurement was within ${\pm}0.08$ pH unit in the pH range of sample solution of $pK_I{\pm}1$.

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Study on Lithium Extraction Using Cellulose Nanofiber ( 셀룰로오스 나노 섬유를 활용한 리튬 흡착 및 추출 연구)

  • Raeil Jeong;Jinsub Choi
    • Journal of the Korean institute of surface engineering
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    • v.57 no.1
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    • pp.31-37
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    • 2024
  • The surge in demand for lithium is primarily fueled by the expanding electric vehicle market, the necessity for renewable energy storage, and governmental initiatives aimed at achieving carbon neutrality. This study proposes a straightforward method for lithium extraction utilizing cellulose nanofiber (CNF) via a vacuum filtration process. This approach yields a porous CNF film, showcasing its potential utility as a lithium extractor and indicator. Given its abundance and eco-friendly characteristics, cellulose nanofiber (CNF) emerges as a material offering both economic and environmental advantages over traditional lithium extraction techniques. Hence, this research not only contributes to lithium recovery but also presents a sustainable solution to meet the growing demand for lithium in energy storage technologies.