• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1329-1334
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• 2006

The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).

• 한국환경성돌연변이발암원학회지
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• 제18권2호
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• pp.109-115
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• 1998

Fluorscence in situ hybridization with chromosome-specific probe has been shown to be a valid and rapid method for detection of chromosome rearrangements induced by chemical and physical agents. This method is useful for quantifying structural aberrations, expecially for stable ones, such as translocation and insertion, which are difficult to detect with conventional method in human lymphocyte. In order to use the FISH method as a biodosimeter for monitoring human population exposed to various chemical and physical agent, baseline level of chromosome rearragement was established. Blood from forty four healthy adults were collected and analysed with whole chromosome-specific probes by human chromosome 1,2 and 4. The frequencies of stable translocation were 2.45 per 100 cell equivalent and those of insertion, color juction, acentric and dicentric were 0.32, 3.28, 0.23 and 0.27 per 100 cell equivalent respectively. The frequencies of chromosome rearragements increased with age in both sexes except for dicenrics. From above result, stable aberrations accumulate with age and it may reflect integrated lifetime exposure of adverse environment.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1159-1164
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• 2014

A simple, highly sensitive and selective method based on the rhodamine B-covered gold nanoparticle with dual-readout (colorimetric and fluorometric) detection for $\small{L}$-cysteine is proposed. A mechanism is that citrate-stabilized AuNPs were modified with RB by electrostatic interaction, which enables the nanometal surface energy transfer (NSET) from the RB to the AuNPs, quenching the fluorescence. In the presence of $\small{L}$-cysteine, it was used as a competitor in the NSET by the strongly Au-S bonding to release RB from the Au surface and recover the fluorescence, and the red-to-purple color change quickly, which was monitored simply by the naked eye. Under the optimum conditions, the detection limit is as low as 10 nM. The method possessed the advantages of simplicity, rapidity and sensitivity at the same time. The method was also successfully applied to the determination of $\small{L}$-cysteine in human urine samples, and the results were satisfying.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.1985-1989
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• 2013

A simple colorimetric and fluorescent anion sensor 1 based on salicylimine showed a high selectivity and sensitivity for detection of cyanide in aqueous solution. The receptor 1 showed high selectivity toward $CN^-$ ions in a 1:1 stoichiometric manner, which induces a fast color change from colorless to orange and a dramatic enhancement in fluorescence intensity selectively for cyanide anions over other anions. Such selectivity resulted from the nucleophilic addition of $CN^-$ to the carbon atom of an electron-deficient imine group. The sensitivity of the fluorescence-based assay (0.06 ${\mu}M$) is below the 1.9 ${\mu}M$ suggested by the World Health Organization (WHO) as the maximum allowable cyanide concentration in drinking water, capable of being a practical system for the monitoring of $CN^-$ concentrations in aqueous samples.

• BMB Reports
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• 제50권9호
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• pp.478-483
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• 2017

Budding yeast has dozens of prions, which are mutually dependent on each other for the de novo prion formation. In addition to the interactions among prions, transmissions of prions are strictly dependent on two chaperone systems: the Hsp104 and the Hsp70/Hsp40 (J-protein) systems, both of which cooperatively remodel the prion aggregates to ensure the multiplication of prion entities. Since it has been postulated that prions and the remodeling factors constitute complex networks in cells, a quantitative approach to describe the interactions in live cells would be required. Here, the researchers applied dual-color fluorescence cross-correlation spectroscopy to investigate the molecular network of interaction in single live cells. The findings demonstrate that yeast prions and remodeling factors constitute a network through heterogeneous protein-protein interactions.

• Tribology and Lubricants
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• 제35권3호
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• pp.151-157
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• 2019

Insulated oil degradation produces charged by-products, such as acids and hydro-peroxides, which tend to reduce the insulating properties of the oil. In this study, UV-vis spectroscopy measurement technology is developed and experimentally compared with other measurement methods, such as the titration method and IR spectroscopy, to validate its ability to monitor the degradation of electrical insulating paper. The degradation characteristics of the insulating paper are appropriately represented through various types of measurement methods, such as the Tan (delta) method, $CO_2$ gas production measurement, the titration method, and IR spectroscopy. The results are demonstrated to be well comparable to a change in the fluorescence emission ratio (FER), which is defined as the shift in fluorescence intensity in the measured wavelength range, and also to the chromatic ratio, which is defined as a color shift to longer wavelength ranges. The results also show that, by using UV-vis spectroscopy, it is possible to detect the degradation of the insulating paper. This study suggests that UV-vis spectroscopy can be applied as an alternative to high-performance liquid chromatography, which is the internationally recognized measurement technology for cellulose paper degradation. The FER detector is also verified to be useful as an effective condition-monitoring device for power transformers.

• 한국식품과학회지
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• 제13권2호
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• pp.114-120
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• 1981

색소(色素)를 흡착(吸着)시킨 여지(濾紙)를 시료(試料)로 간섭(干涉)필터를 통한 자다선(紫多線)을 조사(照射)한 경우에 $45^{\circ}$ 반사각(反射角)에서 발광(發光) 및 소광(消光)의 세기를 측정하여 신속하고 간편하게 색소(色素)를 감별(鑑別)할 수 있는 방법(方法)을 시도(試圖)하였다. 발광(發光) 스펙트럼 보다는 흡수(吸收) 스펙트럼이 보다 특징적인 패턴을 나타냈다. 흡수대(吸收帶)의 파장영역(波長領域), 분포상태(分布狀態) 및 개수(個數)와 소광(消光)정도를 조사하므로써 착색료(着色料) 종류가 용이하게 판별되었다.

• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.989-1002
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• 2022

Cephalopods, in particular octopus (Octopus vulgaris), have the ability to alter their appearance or body pattern by showing a wide range of camouflage by virtue of their chromatophores, which contain nanostructured granules of ommochrome pigments. Recently, the antioxidant and antimicrobial activities of ommochromes have become of great interest; therefore, in this study, the pH-dependent redox effect of the extraction solvent on the antioxidant potential and the structural characterization of the pigments were evaluated. Cell viability was determined by the microdilution method in broth by turbidity, MTT, resazurin, as well as fluorescence microscopy kit assays. A Live/Dead Double Staining Kit and an ROS Kit were used to elucidate the possible inhibitory mechanisms of ommochromes against bacterial and fungal strains. The results obtained revealed that the redox state alters the color changes of the ommochromes and is dependent on the pH in the extraction solvent. Natural phenoxazinone (ommochromes) is moderately toxic to the pathogens Staphylococcus aureus, Bacillus subtilis, Salmonella Typhimurium and Candida albicans, while the species Pseudomonas aeruginosa and Pseudomonas fluorescens, and the filamentous fungi Aspergillus parasiticus, Alternaria spp. and Fusarium verticillioides, were tolerant to these pigments. UV/visible spectral scanning and Fourier- transform infrared spectroscopy (FTIR) suggest the presence of reduced ommatin in methanol/ HCl extract with high intrinsic fluorescence.

• 대한기계학회논문집B
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• 제38권10호
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• pp.853-858
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• 2014

본 연구는 미세유동칩을 이용하여 당의 일종인 cyclodextrine(CD)과 알루미늄 이온 검출이 가능한 polydiacetylene(PDA)이 집적된 미세섬유를 제작하는 방법을 제안한다. PDA는 공액 고분자의 일종으로 외부 자극에 대해 blue-to-red 색 전이 및 형광이 발현되며 원료가 되는 PCDA의 head group에 따라 자극에 대한 감도가 달라지는 매력적인 특성을 가지고 있다. 따라서, 이온간 교차결합으로 야기되는 하이드로젤 형성 메커니즘과 미세유동칩 내 3차원 유체집속효과를 활용하여 PCDA-EDEA 기반의 diacetylene(DA) 단량체가 집적된 센서 섬유를 제작하였다. 섬유 내 DA 단량체는 UV에 의해 파란색의 PDA로 상 전이가 일어나며 CD나 알루미늄 이온에 반응하여 붉은색으로의 색 전이 및 붉은 형광이 발현되는 특성을 보였다. 또한 형광세기는 CD와 금속 이온의 농도에 따라 변화하는 특성을 나타내었다. 이는 미세섬유가 건조된 경우에도 동일하게 관찰되었다.

• 한국콘텐츠학회논문지
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• 제5권6호
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• pp.146-151
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• 2005

산호는 아름다운 적색의 귀한 유기질 보석으로, 오래전부터 우리나라를 비롯한 아시아에서 선호되어온 전통적인 장신구에 많이 애용되었다. 천연산호와 모조산호에 대한 보석학적 특징을 비교 연구하여 보석으로 사용되는 산호를 감별할 수 있는 기초적인 자료를 만드는 것이 중요하다. 천연산호와 모조산호를 감별하기 위하여 산호의 색, 광택, 투명도, 조흔색, 굴절률, 경도, 염산 반응, 형광 반응, 비중, 편광 현미경 관찰, 전자 현미경 관찰, 화학 분석 및 X선 회절 분석 등의 감별 방법을 실시하였다. 그 결과, 천연 산호의 주성분은 $CaCO_3$이고, 방해석 결정구조를 가지고 있으며 모조 산호들은 탄산염 또는 기타 물질에 색소를 넣어 제조하였음을 알 수 있었다. 그리고 천연 산호와 모조 산호는 X선 회절 분석에 의하여도 구별 되지만 비중, 굴절율, 염산 반응 등과 같은 몇몇 간단한 일반적인 실험을 통해서도 서로 비교되어 감정이 가능하다. 천연산호는 모조 산호에 비해 경도가 높아서 광택이 더 뛰어나다. 파괴검사인 조흔색 확인 작업으로 활용한다.