• Fisheries and Aquatic Sciences
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• 제11권4호
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• pp.219-223
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• 2008

To increase the level of $CoQ_{10}$ production in mass culture, the effects of pH and light irradiation on $CoQ_{10}$ production by Rhodobacter sphaeroides were investigated in a 1-L bioreactor. $CoQ_{10}$ production was growth-associated, and the highest production of $CoQ_{10}$ (1.69 mg/g dry cell) was obtained under uncontrolled pH: this production was 1.7 times higher than that obtained at controlled pH 7. Therefore, pH was a key factor affecting $CoQ_{10}$ production. The effect of light irradiation on $CoQ_{10}$ production was negligible. This result offers an advantage for mass production of $CoQ_{10}$.

• Bulletin of the Korean Chemical Society
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• 제22권3호
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• pp.271-275
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• 2001

We investigated H-type molecular aggregation in a simply spin-coated amorphous homopolymer film of polymethacrylate containing push-pull azobenzene moieties. It was found that the aggregate formation was strongly influenced by thermal treatment an d that the aggregate created in the polymer film could be easily disrupted by irradiation of a linearly polarized light. In the first writing cycle of aggregated polymer film, photo-induced birefringence showed a steep increase to the highest value followed by a gradual decrease to the certain asymptotic value under longer irradiation of a linearly polarized light. This unique behavior could be attributed to the cooperative motion and the disruption of the aggregated molecules under continuous irradiation of light.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.169-173
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• 2007

During laser irradiation, mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in accelerated stress relaxation. Clinically, laser-assisted cartilage reshaping may be used to recreate the underlying cartilaginous framework in structures such as ear, larynx, trachea, and nose. Therefore, research and identification of the biophysical transformations in cartilage accompanying laser heating are valuable to identify critical laser dosimetry and phase transformation of cartilage for many clinical applications. quasi-elastic light scattering was investigated using Ho : YAG laser $(\lambda=2.12{\mu}m\;;\;t_p\sim450{\mu}s)$ and Nd:YAG Laser $(\lambda=1.32{\mu}m\;;\;t_p\sim700{\mu}s)$ for heating sources and He : Ne $(\lambda=632.8nm)$ laser, high-power diode pumped laser $(\lambda=532nm)$, and Ti : $Al_2O_3$ femtosecond laser $(\lambda=850nm)$ for light scattering sources. A spectrometer and infrared radiometric sensor were used to monitor the backscattered light spectrum and transient temperature changes from cartilage following laser irradiation. Analysis of the optical, thermal, and quasi-elastic light scattering properties may indicate internal dynamics of proteoglycan movement within the cartilage framework during laser irradiation.

• 한국토양비료학회지
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• 제15권4호
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• pp.251-257
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• 1982

광조사시간(光照射時間)에 따른 대두유식물(大豆幼植物)의 지방산(脂防酸)과 sterol 조성변화를 경시적으로 분석(分析)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 발아생육기간(發芽生育期間)동안 광조사시간(光照射時間)이 길수록 배축부(胚軸部)의 linoleic acid와 linolenic acid조성(組成)은 증가하였고 palmitic과 stearic acid는 감소(減少)하였다. 2. 발아후(發芽后) 2 일(日)째 근부(根部)의 palmitic과 linolenic acid는 광조사시간(光照射時間)이 길수록 감소(減少)하였고, stearic과 oleic acid는 증가하였다. 3. 발아생육기간(發芽生育期間)동안 자엽부(子葉部)에서 stigmasterol이 주(主)sterol이었고 배축부(胚軸部)와 근부(根部)에서는 sitosterol이 주(主)sterol이었다. 4. 발아후(發芽后) 6 일(日)째의 광조사(光照射) 24시간(時間)에서, 배축부(胚軸部)의 sitosterol이 가장 높았다. 5. 암상태(暗狀態)와 광조사(光照射) 24시간(時間)에서 근부(根部)의 sitosterol조성(組成)은 생육기간(生育期間)이 경과할수록 감소(減少)하였고, 광조사(光照射) 16시간(時間)에서는 sitosterol조성(組成)이 증가하였다.

• 대한의생명과학회지
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• 제16권4호
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• pp.365-376
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• 2010

The purpose of this study was to clarify the effect of light emitting diode (LED) irradiation on healing of impaired wound and alteration of mast cells in experimental diabetic rats. Twenty-four male Sprague-Dawley rats were divided into four groups: excision (Ex), excision-LED irradiation (Ex-LED), diabetes + excision (DM) and diabetes + excision + LED irradiation (DM-LED). Diabetes was induced in rats by streptozotocin (STZ) injection (70 mg/kg, single dose) and 6 mm punch excision wounds were created on the back after shaving hair. The LED-irradiated rats were treated to a daily dose of $5\;J/cm^2$ LED (630 nm) light for 11 days after surgery, and were killed at day 1, 3, 7 and 11. The lesion and adjacent skin tissues were excised, fixed with 10% buffered formalin and embedded with paraffin. For evaluation of wound healing, hematoxylin-eosin (HE) and Masson trichrome staining were performed. Mast cells (MCs) were stained with toluidine blue (pH 0.5) and quantified using a computerized image analysis system. The proliferation activity of keratinocyte in skin tissues was analyzed on sections immunostained with proliferative cell nuclear antigen (PCNA). The results showed that wound healing rate, collagen density and neo-epidermis length, number of PCNA-positive cells, fibroblasts and mast cells were significantly higher in the LED-irradiated rats than in the DM and Ex rats throughout the periods of experiment. Exceptionally, the number of MCs was significantly lower at day 11 compared with day 7 after surgery in the all groups. These findings suggest that the LED irradiation may promote the tissue repair process by accelerating keratinocyte and fibroblast proliferation and collagen production in normal rats as well as in diabetic rats, and MCs may play an important role at an early stage of skin wound healing in normal and diabetic rats.

• Journal of Photoscience
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• 제1권2호
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• pp.83-88
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• 1994

The synergic effect of iron plus blue light on the peroxidation of membrane lipid was investigated, using liposomes made of phospholipid. While strong irradiation did not affect Fe$^{+2}$-promoted lipid peroxidation that turned out to be O$_2$-dependent, ferric iron in bright light exerted a pronounced effect on the initiation of lipid peroxidation: this combined action of light and Fe$^{+3}$ on liposomal membranes was apparently independent of O$_2$. When liposomal samples containing Fe$^{+3}$ were subjected to irradiation, some portions of Fe$^{+3}$ were converted into Fe$^{+2}$. The extent of the Fe$^{+3}$-Fe$^{+2}$ conversion increased with increasing time of irradiation, which resembled the dependence of Fe$^{+3}$-promoted lipid peroxidation on irradiation. Further, it was observed that the effect of irradiation in liposomal samples containing Fe$^{+2}$ was strikingly mimicked by that of Fe$^{+2}$ addition to the same samples. The obligatory requirement of a suitable Fe$^{+3}$/Fe$^{+2}$ ratio for the genesis of iron-dependent lipid peroxidation, a controversial proposition, was also confirmed by the observation that lipid peroxidation was substantially enhanced by the addition of a mixture of Fe$^{+3}$ and Fe$^{+2}$, as compared to the addition of Fe$^{+3}$ or Fe$^{+2}$ alone. The results obtained in this study not only suggest that light acts as an effector for initiating lipid peroxidation, when Fe$^{+3}$ is present in membrane systems, but also imply that any chemical or physical factor that influences the redox states of iron in membranes can play a role in lipid peroxidation reactions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.423-423
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• 2009

Currently, lasers are one of the most popular light sources in use for medical treatment. Many studies on low power lasers are being done in cell culture or through animal tests and most report different findings, making it difficult to verify their true effects. There are shifts in trends of studies from laser and LED that are expensive and generate heat problem to LED that are economically effective and safe. Its near infrared rays can penetrate deep into skin or muscle, up to 23 cm, without causing thermal damage or impairing neighboring tissues. This study verified the performance and effectiveness of an LED irradiator that was designed to emit similar wavelengths to that of a laser and thus could be used instead of a low level laser therapy in experiments on animals. And then, each experiment was performed to irradiation group and non-irradiation group for NTacSam:SD tissue cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of NTacSam:SD tissue cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• 디지털융복합연구
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• 제14권11호
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• pp.639-644
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• 2016

본 연구의 목적은 발광 다이오드 (LED)을 인간 피부 각질 세포에 조사 시 콜라겐, 프로 콜라겐의 증식 발현을 조사하기 위해 실시되었었다. LED 조사 시 안전하게 인간의 피부에 적용할 수 있는지 여부를 결정하기 위해, LED 조사의 증식 효과는 인간 표피 각질세포에서 MTS 분석으로 결정하였다. 470nm의 파장 조사는 세포 독성 없이 mRNA의 콜라겐의 발현, 프로 콜라겐을 증가시켰으며, 이 결과는 470nm LED 조사가 피부각질세포 증식 효과와 콜라겐 합성에 영향을 미칠 수 있음을 시사한다. 또한 LED 조사시 독성 효과는 인간 피부 섬유 아세포 (HDF)에서 MTS 분석으로 결정 한 결과 세포 증식에 독성을 나타내지 않았다. 470nm LED 조사시 시험 관내 콜라겐 합성 활동을 증가시킴으로 피부미용 및 융복합적인 부분에 활용할 수 있는 기초 자료로 활용이 가능하다고 사료된다.

• Journal of Photoscience
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• 제9권2호
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• pp.427-429
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• 2002

We studied iron release from ferritin by irradiating the visible light, and then followed ferritin-mediated lipid peroxidation in the rod outer segment (ROS) fraction of the porcine retina. In the presence of several phosphorus compounds such as ADP and ATP, iron release from ferritin at pH 7.0 could be induced by irradiation of the visible light to the reaction mixtures. Furthermore, iron release from ferritin in the presence of ADP depended on the incubation time and the visible light irradiation. Moreover, we investigated lipid peroxidation level in the ROS fraction by two independent assay systems including the thiobarbituric acid (TBA) and ferrous oxidation/xylenol orange (FOX) methods. The visible light induced ferritin-mediated lipid peroxidation in the ROS fraction in time- and irradiance-dependent manners. In the dark condition, iron release and lipid peroxidation were not observed. Iron release from ferritin by irradiating the visible light may play an important role in the etiology of phototoxic injuries in vivo.

• 한국태양에너지학회 논문집
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• 제39권4호
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• pp.55-67
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• 2019

Recently, as the amount of particulate matter blowing from China increases, the domestic air environment is rapidly deteriorating. This pollution of the atmosphere greatly affects the light energy reaching the ground. Particularly, since the light enters the solar cell module in various forms, the amount of input energy of the solar power generation system may be changed depending on the ratio of direct beam irradiation and diffused horizontal irradiation. In this paper, we analyze how the ratio of direct beam component and diffused component on global horizontal irradiation varies with the atmospheric conditions. In addition, the reliability of the regression equation, designed to decompose the global horizontal irradiation into horizontal direct beam irradiation and diffused horizontal irradiation, was verified according to the level of air pollution. So, we derive the most suitable decomposition model for use in domestic climatic conditions in Korea by comparing the ratio of direct and diffuse component on the horizontal which is calculated with Perez model and Watanabe model using the meteorological weather data observed for 14 months. Finally, to reduce the error of the transposition result, we verified the reliability of the decomposition which depends on the atmospheric environment.