• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.376-376
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• 2023

전 세계적으로 중요한 담수 자원인 지하수의 미세플라스틱 오염에 대한 우려가 커지고 있다. 지하수 환경에서 미세플라스틱의 오염을 예측하고 평가하기 위해 대수층 내 현장 실태조사가 수행 중에 있으며, 실험실 규모의 컬럼 실험을 통해 지하수에서 미세플라스틱 이동 메커니즘을 조사하는 연구들이 수행되고 있다. 이러한 연구들은 많은 개수의 분석 시료를 동반하며, 환경 중 미세플라스틱 정량분석을 위해서 고가의 분석기기(라만분광기, 푸리에 변환 적외선(FTIR) 분광기, 열분해 가스크로마토그래피 질량분석기)를 사용하여 플라스틱의 종류를 판별하고 개수를 측정하고 있다. 또한, 컬럼 실험을 수행한 대부분의 선행 연구에서는 미세플라스틱 정량분석을 위해 탁도 분석, 분광광도계를 이용한 흡광도 분석, 현미경을 이용한 계수 방법 등을 이용하여 고가의 분석기기를 사용하지 않고 연구를 수행하였다. 하지만, 이러한 방법들은 유체 속 다른 물질이 포함되어있을 경우에 민감하고 농도를 비율 혹은 개수로 표현하기 때문에 질량 측면에서 미세플라스틱의 농도를 과소·과대 평가할 수 있다. 특히, 현미경을 이용한 계수 방법의 경우에는 분석에 많은 시간이 소요된다는 단점이 있다. 위에 언급한 다양한 분석법들의 단점들을 보완하기 위하여, 본 연구에서는 대수층 내 미세플라스틱 이동 특성을 규명하기 위한 실내 실험에 사용될 수 있는 형광이미지 기반의 미세플라스틱 정량분석법을 개발하였다. Nile Red 형광염료를 이용하여 미세플라스틱을 염색하고 사진을 촬영하여 미세플라스틱 시료의 질량과 미세플라스틱 형광이미지의 형광강도 간 상관관계를 분석하였다. 또한, Nile Red로 염색된 미세플라스틱 입자의 수중 노출 테스트를 진행하여, 실내 대수층 모의실험 시 미세플라스틱 질량을 정량화할 수 있는 적용 가능성을 평가하였다. 상관 분석 결과, 미세플라스틱 질량과 이미지의 형광강도는 높은 상관관계를 보였으며, 수중 노출 실험 전과 후의 미세플라스틱 입자의 형광강도 차이는 미미한 것으로 나타났다. 이러한 연구결과를 통해 본 연구에서 개발된 미세플라스틱 정량분석 방법이 포화 다공성 매체로 구성된 컬럼실험 시 유출수의 미세플라스틱 질량 추정에 유용하게 사용될 것으로 생각되며, 대수층 내 미세플라스틱의 이동 특성 규명 연구에 많은 도움이 될 것으로 기대된다.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.265-268
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• 2000

Organic electroluminescent(EL) devices have been expected to be useful in novel-type flat-panel displays. This paper has fabricated and analyzed a red organic EL device with the use of organic dyes, such as DCMI and Nile Red. In this paper, the light emitting layer consists of tris-(8-hydroxyquiniline) aluminum(Alq$_3$) doped with organic dyes.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.525-526
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• 2007

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.746-750
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• 2011

Fluorescence correlation spectroscopy (FCS) is an emerging fluorescence technique used to study the dynamics of proteins on a millisecond to microsecond time scale at the single-molecule level. Solution pH-modulated protein conformational changes can be manifested by binding rate, fluorescence lifetime, and binding specificity of a probe molecule. The fluorescence lifetime of Nile red (NR) bound to apomyoglobin (apoMb) was measured to be $6{\pm}0.3$ ns, much longer than that in water solution ($2.9{\pm}0.2$ ns). As the unfolding population of apoMb increased by lowering pH of solution, the fraction for the longer lifetime of NR decreased with an increasing fraction for the shorter lifetime of NR in water. Unlike 1-anilino-8-naphthalene sulfonic acid, which has many lifetimes due to nonspecific binding to the unfolded apoMb, NR bound to apoMb possesses only a single lifetime. These results suggest that NR binds specifically to native apoMb and thus can be utilized to probe the folding/unfolding dynamics of apoMb using FCS.

• Toxicological Research
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• v.27 no.4
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• pp.211-216
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• 2011

Herbal medicines are widely used in many countries for the treatment of many diseases. Although the use of herb extracts as alternative medicine is growing, their toxicological properties have not been thoroughly investigated. In this study, we have investigated the effects of water and ethanol extracts of 18 herbs on the hepatic lipid metabolism and steatogenic hepatotoxicity. Ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa induced lipid accumulation in Sk-hep1 human hepatoma cells as determined by Nile red staining. These extracts increased the luciferase activity of sterol regulatory element (SRE) and decreased that of peroxisome proliferator response element (PPRE), indicating the possibilities of enhanced fatty acid synthesis and decreased fatty acid oxidation. To identify the components responsible for the fat accumulation, we tested 50 chemicals isolated from the nine herbs. Apigenin, luteolin, pectolinarin and lupeol from Cirsium japonicum, 8-methoxypsoralen and umbelliferone from Foeniculum vulgare and pomonic acid and jiocerebroside from Rehmanniae glutinosa significantly increased the accumulation of lipid droplets. These results suggest that ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa can cause fatty liver disease by decreasing ${\beta}$-oxidation of fatty acid and increasing lipogenesis.

• Journal of Photoscience
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• v.11 no.32
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• pp.47-53
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• 2004

A laser scanning fluorescence microscope system has been fabricated for single molecule detection (SMD). Problems associated with the system set-up have been discussed along with proper suggestions. Based on the SMD results obtained by using the apparatus, a statistical method has been suggested to determine the minimum number of required molecules to form a group of uniform average in a selected error range.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.110-114
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• 2002

The study was carried out to investigate the changes of haematological constituents induced by dietary exposure of Hexachlorobenzene (HCB) and Polychlorinated biphenyls (PCBs) in nile tilapia, Oreochhromis niloticus. The nile tilapia were fed pellet with 0.05, 0.25 and 0.50 mg/kg body weight/day of HCB and PCBs for 30 days, respectively. HCB ($\ge$ 0.25 mg/kg) induced a significantly decreased the red blood cell count at 30 days, and the hemoglobin concentration and hematocrit value were significantly decreased after 20 days to 0.50 mg/kg. The diminution of red blood cell count, hemoglobin concentration and hamatocrit value by PCBs was found after 20 days at $\ge$0.25 mg/kg. The concentrations of calcium decreased significantly at 30 days at $\ge$0,25 mg/kg of PCBs-diet. However, magnesium and inorganic phosphorus did not show any noticeable changes in the range of 0.05$\~$o.50 mg/kg of HCB and PCBs compared to control group during the experimental period, The low concentration of total protein was observed at the last day of experiment to 0.50 mg/kg of HCB-diet, while total protein initiated to increase from 20 days at the 0.25 mg/kg of PCBs-diet. The glucose was significantly increased after 20 days at $\ge$0,25 mg/kg of HCB and PCBs, A significant increment GOT and GPT activities was noticed after 20 days at 0.50 mg/kg of HCB and PCBs, These results indicate that hematological and serum biochemical changes in the nile tilapia by dietary exposure to HCB and PCBs are affected at more than 0,25 mg/kg after 20 days.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.628-632
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• 2013

Arthrospira platensis (A. platensis) is an economically important microalgae because it has carbohydrates, lipids, proteins and a number of phytochemicals. It is also a valuable source used in the production of biodiesel and functional foods. In this study, A. platensis was exposed to electron beam irradation (240 kGy) and induced random mutagenesis for strain improvement. Several mutants were obtained, and the resulting mutant was designated as EB29. The growth rate and chlorophyll content of EB29 was similar to those of wild type. However, the lipid content of EB29 was increased seven-fold compared to that of wild type when comparing the nile red fluorescent intensity. Semi-quantitative analysis of EB29 using the calibration plot of standard lipid, triolein, represented $78.6{\mu}g/mL$, which increased 2 times compared to wild type ($41.4{\mu}g/mL$). When analyzing the fatty acid profile of EB29, polyunsaturated fatty acids (PUFAs), such as gamma-linolenic acid (GLA) in EB29 increased about six-fold. Moreover, fatty acids affecting the quality of biodiesel increased compared to that of wild type. Thus, electron beam could be used for the strain improvement of microalgae in order to accumulate PUFAs and alteration of fatty acid profile for biodiesel.

• Journal of Life Science
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• v.32 no.2
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• pp.142-147
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• 2022

Oxysterols are known to be involved in the physiopathology of atherosclerosis. Since 7-ketocholesterol (7-KC) is found in large amounts in oxysterols and in atherosclerotic plaque, the study on how 7-KC may affect monocyte differentiation induced by phorbol myristate acetate (PMA) in the monocytic cell line, THP-1, is essential. 7-KC induced a dose-dependent reduction in cell proliferation without inducing cytotoxicity, and the substantial staining of Nile red demonstrates the increased absorption of intracellular lipids. Although 7-KC itself did not increase cell adhesion, it markedly decreased the adhesion of cells treated with PMA. Furthermore, by observing the effect of 7-KC on phagocytosis using fluorescent-labeled latex beads, 7-KC's ability to abolish phagocytosis in PMA-stimulated macrophages was illustrated. The effect of 7-KC on the expression of selected protein markers on the process of differentiation induced by PMA in THP-1 cells was also examined. 7-KC inhibited expression of ICAM-1, CD11a, SR-A1, and SR-B2 (CD36) in PMA-stimulated THP-1 cells. Conversely, 7-KC drastically increased the expression of SR-D1 (CD68)in PMA-stimulated THP-1 cells. In conclusion, these results suggest that 7-KC modulates monocyte differentiation and activation via the intracellular accumulation of lipid droplets.

• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.69-75
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• 2018

In this study, we propose a multichannel interdigitated capacitor (IDC) sensor for detecting the bitterness of coffee. The operating principle of the device is based on the variation in capacitance of a sensing membrane in contact with a bitter solution. Four solvatochromic dyes, namely, Nile red, Reichardt's dye, auramine-O, and rhodamine-B, were mixed with polyvinylchloride (PVC) and N,N-dimethylacetamide (DMAC), to create four different types of bitter-sensitive solutions. These solutions were then individually inserted into four interdigitated electrodes (IDEs) using a spin coater, to prepare four distinct IDC sensors. The sensors are capable of detecting bitterness-inducing chemical compounds in any solution, at concentrations of approximately $1{\mu}M$ to 1 M. The sensitivity of the IDC bitterness sensor containing the Reichardt's dye sensing-membrane was approximately 1.58 nF/decade. The multichannel sensor has a response time of approximately 6 s, and an approximate recovery time of 5 s. The proposed sensor offers a stable sensing response and linear sensing performance over a wide measurement range, with a correlation coefficient ($R^2$) of approximately 0.972.