• 대한화장품학회지
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• 제48권3호
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• pp.245-254
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• 2022

본 연구에서는 655 nm에서 저출력 레이저와 625 ± 5 nm와 850 ± 10 nm에서 파장을 방출하는 LED를 이용한 복합 광선 요법이 탈모 및 두피에 나타나는 효능을 조사하고자 하였다. 이번 연구에는 총 33 명의 시험대상자가 등록되었다. 각 시험대상자는 Low-level laser therapy (LLLT)와 light-emitting diode (LED) 기기를 매일 10 min 씩 12 주간 두피와 모발에 사용했다. LLLT와 LED 기기를 사용한 지 12 주 후, 두피의 붉은기, 탄력, 수분 함량에서 상당한 개선이 있었으며, 모발의 윤기와 인장 강도, 탈락 모발 수가 개선되었다. 시험대상자가 시험 기기를 사용하는 기간 동안 특별한 피부 이상반응에 대한 보고는 없었다. LLLT와 LED를 이용한 복합 광선 요법은 탈모와 두피 상태 개선에 효과적인 요법임이 입증되었다.

• Medical Lasers
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• 제8권2호
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• pp.50-58
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• 2019

Background and Objectives Low-level light therapy (LLLT) is an application of low-power light for various purposes such as promoting tissue repair, reducing inflammation, causing analgesia, etc. A previous study suggested the effect of light emitting diode (LED) light with the wavelength of 740 nm for promoting wound healing of corneal epithelial cells. This current study aimed to confirm the effect of LLLT for managing inflammation of a dry eye disease (DED) mouse model. Materials and Methods A total of 50C57BL/6 female mice were randomly grouped into 5 groups to compare the effect of LLLT:1) Control group, 2) Only LLLT group, 3) Dry eye group, 4) LLLT in dry eye group, and 5) Early treatment group. DED was induced with 4 daily injections of scopolamine hydrobromide and desiccation stress for 17 days, and LLLT at 740 nm was conducted once every 3 days. To analyze the effect of LLLT on the DED mouse model, tear volume, corneal surface irregularities, and fluorescence in stained cores were measured, and the level of inflammation was assessed with immunohistochemistry. Results The DED mouse model showed significant deterioration in the overall eye condition. After LLLT, the amount of tear volume was increased, and corneal surface irregularities were restored. Also, the number of neutrophils and the level of inflammatory cytokines significantly decreased as well. Conclusion This study showed that LLLT at 740 nm was effective in controlling the corneal conditions and the degree of inflammation in DED. Such findings may suggest therapeutic effects of LLLT at 740 nm on DED.

• ALGAE
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• 제38권4호
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• pp.283-294
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• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• 한국산림과학회지
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• 제90권4호
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• pp.476-487
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• 2001

본 연구는 내음수(耐陰樹)가 임상(林床)의 낮은 광도조건에 적응하는 기작을 구명하기 위해서, 양수(陽樹)와 내음수(耐陰樹)의 생육 광도 저하에 대한 광합성계(光合成系)의 적응반응을 서로 비교하였다. 이태리포플러, 음나무, 졸참나무 1년생 묘목을 대상으로 PPFD $920{\mu}mol\;m^{-2}s^{-1}$과 PPFD $80{\mu}mol\;m^{-2}s^{-1}$의 광도조건에서 5개월간 생장한 개체의 엽록소함량, 잎의 분광특성, 광합성특성 등을 조사하였다. 그 결과 양수인 이태리포플러는 생육 광도의 저하로 엽면적, 단위 엽면적 당의 엽록소함량, 빛의 흡수율 및 광합성에 대한 이용효율 등이 감소하고, 광합성의 광화학계 및 탄소고정계의 활성 저하로 낮은 광합성능력을 나타냈다. 그러나 내음성이 이태리포플러보다 강한 음나무와 졸참나무는 엽면적, 엽록소함량, 순양자수율을 증가시켜 빛의 흡수량과 광합성에 대한 이용효율을 높이는 적응반응을 나타냈다. 그리고 이들 수종은 낮은 광도에서도 광합성의 광화학계 및 탄소고정계의 활성이 정상적으로 유지되고 있음을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1678-1681
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• 2004

The light-transmission technique has been applied to a slit rheometer for measuring red blood cell aggregation as well as blood viscosity over a range of shear rates. For measurement of blood viscosity and aggregation, instantaneous pressure and transmit-light intensity are measured with time. Using a precision pressure measurement, one can determine the shear stress and shear rate. In addition, a transmitted light through a blood sample indicates degree of RBC aggregation. With abruptly flowing with high shear rate, RBCs rapidly disaggregate and the intensity of the transmitted light becomes low. When continuously flowing with decreasing shear rate, RBCs tend to re-aggregate and the corresponding transmit-intensity gradually increases with time. The light intensity as a degree of RBC aggregation is plotted against shear rate and compared with blood viscosity. The advantages of this design are dual measurement at a time, simplicity, i.e., ease of operation and no moving parts, low cost, short operating time, and the disposable kit which is contacted with blood sample.

• 생물환경조절학회지
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• 제13권1호
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• pp.44-50
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• 2004

본시험은 백침계 오이에 있어 착과기 이후의 저광도 조건이 생육 및 수량에 미치는 영향을 검토코자 수행되었다. 광도 처리는 무처리를 비롯하여 100, 200, 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$로 되도록 하였다. 초장과 측지길이는 광도가 낮았던 처리에서 크게 감소되었으나, 저광도 처리간에는 차이를 보이지 않았다. 엽면적과 근중은 100${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$에서 가장 적었으나, 200과 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$처리간에는 차이를 보이지 않았다. 광합성량은 저광도가 될수록 감소되었다. 엽록소 함량과, 근활력 및 일비액 역시 낮은 광도에서 감소하였는데, 200 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$과 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$처리간에는 차이를 보이지 않았다. 잎의 기공 관찰 결과 낮은 광도에서 기공세포의 발달이 억제되었고 기공의 개도도 완전하지 않았으며, 기공크기가 작았으나 기공수는 증가하였다. 낮은 광도 하에서 잎에 황화현상과 유과 형태의 비정상과가 발생되었다. 또한 잎의 Mg와 Ca의 흡수량이 광도가 낮아짐에 따라 저하되었다. 수확과수는 자연광에 비하여 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$에서 65%, 200고 100 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$에서 각각 80%와 90%의 수량감소를 보였다. 이러한 저광 조건은 처리 후 2주 정도의 초기수량에 크게 영향을 끼쳤으며, 특히 측지 수확과수가 현저히 줄어드는 결과를 보였다.

• 한국세라믹학회지
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• 제54권5호
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• pp.429-437
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• 2017

Micro hollow plate type silica with low refraction properties was synthesized and its hollow structure was applied as an optical structure to develop a light diffusion material that simultaneously satisfies the requirements of good light diffusibility, high transmissibility, and high luminance. The developed light diffusion material was applied to a light diffusion film and the film's optical properties were assessed. Hollow silica was synthesized by precipitation method using $Mg(OH)_2$ core particles, sodium silicate, and ammonium sulfate as the silica precursors. The concentration of the silica precursor was adjusted to control hollow silica shell thickness. The total light transmittance of the light diffusion film composed of the hollow silica was 94.55%, which was 4.57% higher than that of the PC film; new film's haze was 71.20%, which was 70.9% higher. Furthermore, the luminance increased by 5.34% compared to that of the light source. The reason for the results is not only that the micro plate type hollow silica, which has a low refractive property, played a role in reducing the difference in refractive index between the medium boundaries, but also that there was a light-concentrating effect due to the changing of light paths to the front direction inside the hollow structure. Optical simulation verified the enhanced optical properties when hollow silica was applied to the light diffusion film.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7256-7261
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• 2015

본 논문은 식물 재배시스템을 제작하고 LED 광원은 단색광 3개(적색, 청색, 백색), 혼합광 3개(적색1+청색1, 적색2+청색1, 적색1+청색2)를 제작하여 사용하였다. 제작한 식물 재배시스템을 이용하여 LED 광원별 광 특성, 광량의 변화에 따른 조도 및 PPFD의 특성과 식물성장을 분석하였다. 분석결과 LED 광원의 광 효율은 백색 광원이 125 lm/W로 높으며 적색1+청색2 광원은 9.9 lm/W로 낮았다. 이러한 결과로 단색광이 혼합광 보다 광효율이 좋은 것을 확인 할 수 있었다. LED의 파장별 PPFD ($25{\mu}mol$, $50{\mu}mol$, $100{\mu}mol$) 조도값 크기는 백색 LED가 높으며 청색 LED가 낮았다. 따라서 LED 광원의 다양한 단색 혼합광 파장대역 조합에 따라 식물성장에 적합한 효율적인 LED 조명 시스템을 구성할 수 있다.

• 한국광학회지
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• 제28권6호
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• pp.273-280
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• 2017

본 논문에서는 낮은 도로 조명을 위한 freeform reflector를 설계하였다. 높이에 비해 넓은 차선까지 배광을 보내야 하는 낮은 도로 조명의 경우, 기존의 등주식 도로 조명에 비해 균제도를 맞추기 힘들다는 단점이 있다. 조명 등급 M3를 만족시키기 위해 reflector를 part 9개로 나누어 part 별 반사면의 기울기를 변화시켜 원하는 배광을 갖도록 하였고, 각 점을 기준으로 fitted curve를 그려 이에 따른 수식을 도출하였다. LightTools의 street light simulation을 통해 M3 조명 등급에 만족하는 것을 확인하였고 직접 제작하여 실제 도로상에서 조명 등급을 만족시키며 설계 결과에 대한 타당성을 입증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권4호
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• pp.980-997
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• 2024

To improve the brightness of images and reveal hidden information in dark areas is the main objective of low-light image enhancement (LLIE). LLIE methods based on deep learning show good performance. However, there are some limitations to these methods, such as the complex network model requires highly configurable environments, and deficient enhancement of edge details leads to blurring of the target content. Single-scale feature extraction results in the insufficient recovery of the hidden content of the enhanced images. This paper proposed an edge detection-based multi-scale feature enhancement network for LLIE (EDMFEN). To reduce the loss of edge details in the enhanced images, an edge extraction module consisting of a Sobel operator is introduced to obtain edge information by computing gradients of images. In addition, a multi-scale feature enhancement module (MSFEM) consisting of multi-scale feature extraction block (MSFEB) and a spatial attention mechanism is proposed to thoroughly recover the hidden content of the enhanced images and obtain richer features. Since the fused features may contain some useless information, the MSFEB is introduced so as to obtain the image features with different perceptual fields. To use the multi-scale features more effectively, a spatial attention mechanism module is used to retain the key features and improve the model performance after fusing multi-scale features. Experimental results on two datasets and five baseline datasets show that EDMFEN has good performance when compared with the stateof-the-art LLIE methods.