• 제목/요약/키워드: Light dependent

검색결과 825건 처리시간 0.029초

W UMa형 별들의 UV 방출선 연구 (UV LINE EMISSIONS OF W UMa STARS)

  • 김용기;한동주
    • Journal of Astronomy and Space Sciences
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    • 제17권1호
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    • pp.39-44
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    • 2000
  • lUE 저분산 자로플 가지고 44i Boo, W UMa, AW UMa및 VW Cep에서 나오는 자외선 방출선들의 특징을 조사하였다 단파장영역과 장파장영역에서의 방출선 선세기를 구하여, 이를 자$\boxUl$선 등급으로 변환하여 광도곡선을 얻었다 단파장 영ff에서 나오는 방출선인 C I, C II, C IV, SiIV, N V에 대한 선세기를 구한 결파, C IV가 모든 별에서 가장 센 방출을 보였으며. Si IV와 NV는 비교적 작은 양의 선세기를 나타내었다. 4개의 W UMa 별 쿵에근 44i Boo가 가장 높은 선세기를 보였으며, 단과장 영역에서는 위상 0.2와 0 8부근에서 자외선 팡도가 maximup을 보이는 변광을 확인하였다 또한, 전이영역에서 나오는 C IV, Si IV, N V 방출선을 합하여 이를 극소기의 태양값과 비교하여 태양보다 최대40배의 높은 활동성을 가지고 있음을 알았다. 짧은 주기를 갖는 별,즉 44i Boo, W UMa, AW UMa순으로 전이영역의 헐동성이 감소하는 것으로 나타났다. 장 파장 영역에서는 AW UMa와 VW Cep의 Mg ll 방출선을 조사하였는데, 단파장의 방출선 보다 뚜렷한 주기적 변광을 보였으며, 이를 이응하여 두 별의 유효온도를 추정하였다..

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Mechanism of the X-ray and Soft Gamma-ray Emissions from the High Magnetic Field Pulsar: PSR B1509-58

  • Wang, Yu;Takata, Jumpei;Cheng, Kwong Sang
    • Journal of Astronomy and Space Sciences
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    • 제30권2호
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    • pp.91-94
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    • 2013
  • We use the outer gap model to explain the spectrum and the energy dependent light curves of the X-ray and soft ${\gamma}$-ray radiations of the spin-down powered pulsar PSR B1509-58. In the outer gap model, most pairs inside the gap are created around the null charge surface and the gap's electric field separates the opposite charges to move in opposite directions. Consequently, the region from the null charge surface to the light cylinder is dominated by the outflow current and that from the null charge surface to the star is dominated by the inflow current. We suggest that the viewing angle of PSR B1509-58 only receives the inflow radiation. The incoming curvature photons are converted to pairs by the strong magnetic field of the star. The X-rays and soft ${\gamma}$-rays of PSR B1509-58 result from the synchrotron radiation of these pairs. The magnetic pair creation requires a large pitch angle, which makes the pulse profile of the synchrotron radiation distinct from that of the curvature radiation. We carefully trace the pulse profiles of the synchrotron radiation with different pitch angles. We find that the differences between the light curves of different energy bands are due to the different pitch angles of the secondary pairs, and the second peak appearing at E > 10 MeV comes from the region near the star, where the stronger magnetic field allows the pair creation to happen with a smaller pitch angle.

일광노출에 의한 천연염직물의 색상변화에 관한 연구 (Color Changes of Natural-Dyed Fabrics under Sunlight)

  • 박명자;이연희;윤양노
    • 한국의상디자인학회지
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    • 제6권3호
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    • pp.45-53
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    • 2004
  • Natural dyes have poor colorfastness as a result of the exposure of the dyed fabric to sunlight encountered during the display or wearing. As colors on fabrics fade excessively under sunlight, it is a problem to infer and restore the historic textiles with natural-dyed fabrics to original colors. The object of this study is to analyse the factors affected to color change under light. In experimental, fifteen natural dyes were dyed by the Korean traditional dyeing methods onto natural fiber fabrics: cotton, silk, ramie, and flex. Total 49 dyed fabrics in combination with dyes and fibers were used for the specimen. The Weather-O-meter was used for evaluating the effects of exposure to light for 2.5 to 450 hours. The process of color changes in the CIEL *A*B* color-order system to the exposure time were determined by spectrophotometer at 10$^{\circ}$ observer. Sunlight exposure caused significant changes in the color of natural-dyed fabrics. The degree and nature of color changes on the fabrics were dependent on the combination of fiber and the type of dye used. The groups of violet(Lithospermum erythrorhizon Sieb.et Zucc.) and black color(Ailanthus altissima Swingle, Phus trichocarpa Miq) yielded excellent colorfastness to light. The group of indigo blue color(Polygonum tinctorium Lour.) was also very resistant to fading in both exposure except silk. Whereas the dye groups of Red, Yellow, Orange, Brown colors indicated greatest changes in fading, particularly Carthamus tinctorius L.

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A Novel All-trans Retinoid Acid Derivative N-(3-trifluoromethyl-phenyl)-Retinamide Inhibits Lung Adenocarcinoma A549 Cell Migration through Down-regulating Expression of Myosin Light Chain Kinase

  • Fan, Ting-Ting;Cheng, Ying;Wang, Yin-Feng;Gui, Shu-Yu;Chen, Fei-Hu;Zhou, Qing;Wang, Yuan
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권18호
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    • pp.7687-7692
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    • 2014
  • Aim: To observe the effects of a novel all-trans retinoid acid (ATRA) derivative, N-(3-trifluoromethyl-phenyl)-retinamide (ATPR), on lung adenocarcinoma A549 cells and to explore the potential mechanism of ATPR inhibiting of A549 cell migration. Materials and Methods: The cytotoxicity of ATRA and ATPR on A549 cells was assessed using MTT assay. Wound healing assays were used to analyze the influences of ATRA, ATPR, ML-7 (a highly selective inhibitor of myosin light chain kinase (MLCK)), PMA (an activator of MAPKs) and PD98059 (a selective inhibitor of ERK1/2) on the migration of A549 cells. Expression of MLCK and phosphorylation of myosin light chain (MLC) were assessed by Western blotting. Results: ATRA and ATPR inhibited the proliferation of A549 cells in a dose- and time-dependent manner, and the effect of ATPR was much more remarkable compared with ATRA. Relative migration rate and migration distance of A549 cells both decreased significantly after treatment with ATPR or ML-7. The effect on cell migration of PD98059 combining ATPR treatment was more notable than that of ATPR alone. Moreover, compared with control groups, the expression levels of MLCK and phosphorylated MLC in A549 cells were both clearly reduced in ATRA and ATPR groups. Conclusions: ATPR could suppress the migration and invasion of A549 cells, and the mechanism might be concerned with down-regulating the expression of MLCK in the ERK-MAPK signaling pathway, pointing to therapeutic prospects in lung cancer.

Fluorescence Resonance Energy Transfer in Calf Thymus DNA from a Long-Lifetime Metal-Ligand Complex to Nile Blue

  • Kang, Jung-Sook;Lakowicz, Josepb R.
    • BMB Reports
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    • 제34권6호
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    • pp.551-558
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    • 2001
  • We extended the measurable time scale of DNA dynamics to submicrosecond using a long-lifetime metal-ligand complex, $[Ru(phen)_2(dppz)]^{2+}$ (phen=1,10-phenanthroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuPD), which displays a mean lifetime near 350 ns. We partially characterized the fluorescence resonance energy transfer (FRET) in calf thymus DNA from RuPD to nile blue (NB) using frequency-domain fluorometry with a high-intensity, blue light-emitting diode (LED) as the modulated light source. There was a significant overlap of the emission spectrum of the donor RuPD with the absorption spectrum of the acceptor NB. The F$\ddot{o}$rster distance ($R_0$) that was calculated from the spectral overlap was $33.4\;{\AA}$. We observed dramatic decreases in the steady-state fluorescence intensities of RuPD when the NB concentration was increased. The intensity decays of RuPD were matched the closest by a triple exponential decay. The mean decay time of RuPD in the absence of the acceptor NB was 350.7 ns. In a concentration-dependent manner, RuPD showed rapid intensity decay times upon adding NB. The mean decay time decreased to 184.6 ns at $100\;{\mu}M$ NB. The FRET efficiency values that are calculated from the mean decay times increased from 0.107 at $20\;{\mu}M$ NB to 0.474 at $100\;{\mu}M$ NB concentration. The use of FRET with a long-lifetime metal-ligand complex donor is expected to offer the opportunity to increase the information about the structure and dynamics of nucleic acids.

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Estimation of Moisture Content in Comminuted Miscanthus based on the Intensity of Reflected Light

  • Cho, Yongjin;Lee, Dong Hoon
    • Journal of Biosystems Engineering
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    • 제40권3호
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    • pp.296-304
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    • 2015
  • Purpose: The balance between miscanthus production and its cost effectiveness depends greatly on its moisture content during post processing. The objective of this research was to measure the moisture content using a non-destructive and non-contact methodology for in situ applications. Methods: The moisture content of comminuted miscanthus was controlled using a closed chamber, a humidifier, a precision weigher, and a real-time monitoring software developed in this research. A CMOS sensor equipped with $50{\times}$ magnifier lens was used to capture magnified images of the conditioned materials with moisture content level from 5 to 30%. The hypothesis is that when light is incident on the comminuted particles in an inclined manner, higher moisture content results in light being reflected with a higher intensity. Results: A linear regression analysis for an initiative hypothesis based on general histogram analysis yielded insufficient correlations with low significance level (<0.31) for the determination coefficient. A significant relationship (94% confidence level) was determined at level 108 in a reverse accumulative histogram proposed based on a revised hypothesis. A linear regression model with the value at level 108 in the reverse accumulative histogram for a magnified image as the independent variable and the moisture content of comminuted miscanthus as the dependent variable was proposed as the estimation model. The calibrated linear regression model with a slope of 92.054 and an offset of 32.752 yielded 0.94 for the determination coefficient (RMSE = 0.2%). The validation test showed a significant relationship at the 74% confidence level with RMSE 6.4% (n = 36). Conclusions: To compensate the inconsistent significance between calibration and validation, an estimation model robust against various systematic interferences is necessary. The economic efficiency of miscanthus, which is a promising energy resource, can be improved by the real-time measurement of its crucial material properties.

TFT-LCD용 휘도 성능을 향상시키는 나노 와이어 그리드 편광 필름의 제작 (Fabrication of a Nano-Wire Grid Polarizer for Brightness Enhancement in TFT-LCD Display)

  • 허종욱;남수용
    • 한국인쇄학회지
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    • 제29권3호
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    • pp.105-124
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    • 2011
  • TFT-LCD consists of LCD panel on the top, circuit unit on the side and BLU on the bottom. The recent development issues of BLU-dependent TFT-LCD have been power consumption minimization, slimmerization and size maximization. As a result of this trend, LED is adopted as BLU instead of CCFL to increase brightness and to reduce thickness. In liquid crystal displays, the light efficiency is below 10% due to the loss of light in the path from a light source to an LCD panel and presence of absorptive polarizer. This low efficiency results in low brightness and high power consumption. One way to circumvent this situation is to use a reflective polarizer between backlight units and LCD panels. Since a nano-wire grid polarizer has been known as a reflective polarizer, an idea was proposed that it can be used for the enhancement of the brightness of LCD. The use of reflective polarizing film is increasing as edge type LED TV and 3D TV markets are growing. This study has been carried out to fabrication of the nano-wire grid polarizer(NWGP) and investigated the brightness enhancement of LCD through polarization recycling by placing a NWGP between an c and a backlight unit. NWGPs with a pitch of 200nm were fabricated using laser interference lithography and aluminum sputtering and wet etching. And The NWGP fabrication process was using by the UV imprinting and was applied to plastic PET film. In this case, the brightness of an LCD with NWGPs was 1.21 times higher than that without NWGPs due to polarization recycling.

Interaction of Microtubule-associated Protein 1B Light Chain(MAP1B-LC1) and p53 Represses Transcriptional Activity of p53

  • Kim, Jung-Woong;Lee, So-Youn;Jeong, Mi-Hee;Jang, Sang-Min;Song, Ki-Hyun;Kim, Chul-Hong;Kim, You-Jin;Choi, Kyung-Hee
    • Animal cells and systems
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    • 제12권2호
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    • pp.69-75
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    • 2008
  • The tumor suppressor and transcription factor p53 is a key modulator of cellular stress responses, and can trigger apoptosis in many cell types including neurons. In this study, we have shown that Microtubule-associated protein 1B(MAP1B) light chain interacts with tumor suppressor p53. MAP1B is one of the major cytoskeletal proteins in the developing nervous system and essential in forming axons during elongation. We also demonstrate that both p53 and MAP1B-LC1 interact in the nucleus in HEK 293 cells. Indeed, we show that the MAP1B-LC1 negatively regulates p53-dependent transcriptional activity of a reporter containing the p21 promoter. Consequently, MAP1B light chain binds with p53 and their interaction leads to the inhibition of doxorubicin-induced apoptosis in HEK 293 cells. Furthermore, these examinations might be taken into consideration when knock-down of MAP1B-LC1 is used as a cancer therapeutic strategy to enhance p53's apoptotic activity in chemotherapy.

Light-regulated Translation of Chloroplast Reaction Center Protein D1 mRNA in Chlamydomonas reinhardtii

  • Kim, Jungmook
    • 한국식물학회:학술대회논문집
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    • 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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    • pp.57-62
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    • 1999
  • Light-regulated translation of chloroplast mRNAs requires nuclear-encoded trans-acting factors that interact with the 5' untranslated region (UTR) of these mRNAs. A set of four proteins (60, 55, 47, and 38 kDa) that bind to the 5'-UTR of the psbA mRNA had been identified in C. reinhardtii. 47 kDa protein (RB47) was found to encode a chloroplast poly (A)-binding protein (cPABP) that specifically binds to the 5'-UTR of the psbA mRNA, and essential for translation of this mRNA, cDNA encoding 60 kDa protein (RB60) was isolated, and the amino acid sequence of the encoded protein was highly homologous to plants and mammalian protein disulfide isomerases (PDI), normally found in the endoplasmic reticulum (ER). Immunoblot analysis of C. reinhardtii proteins showed that anti-PDI recognized a distinct protein of 56 kDa in whole cell extract, whereas anti-rRB60 detected a 60 kDa protein. The ER-PDI was not retained on heparin-agarose resin whereas RB60 was retained. In vitro translation products of the RB60 cDNA can be transported into C. reinhardtii chloroplast in vitro. Immunoblot analysis of isolated pea chloroplasts indicated that higher plant also possess a RB60 homolog. In vitro RNA-binding studies showed that RB60 modulates the binding of cPABP to the 5'-UTR of the psbA mRNA by reversibly changing the redox status of cPABP using redox potential or ADP-dependent phosphorylation. Site-directed mutagenesis of -CGHC- catalytic site in thioredoxin-like domain of RB60 is an unique PDI located in the chloroplast of C. reinhardtii, and suggest that the chloroplast PDI may have evolved to utilize the redox-regulated thioredoxin like domain as a mechanism for regulating the light-activated translation of the psbA mRNA.

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동적광산란법을 이용한 아밀로즈 함량에 따른 전분 분자 구조 변화 분석 (Evaluation of Molecular Structural Changes in Starch Depending on Amylose Content Using Dynamic Light Scattering)

  • 문주현;마진경;김종예
    • 한국식품영양과학회지
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    • 제46권5호
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    • pp.653-658
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    • 2017
  • 본 연구에서는 동적광산란법을 이용하여 아밀로즈 함량과 용매 조건에 따른 전분 분자 구조 변화를 규명하였다. 분자량이 다른 여러 가지 덱스트란 표준물질을 이용하여 동적광산란법의 정확성을 검증하였으며, 이를 전분에 적용해본 결과 아밀로즈 함량에 따른 전분 분자의 $D_h$ 변화를 규명할 수 있었고 아밀로즈 함량이 높아질수록 전분 분자의 $D_h$ 값이 증가하였다. 또한, 용매 조건에 따른 전분 분자의 $D_h$ 변화를 동적광산란법으로 규명할 수 있었으며, NaCl의 경우 농도가 높아질수록 아밀로펙틴의 $D_h$가 증가했지만, 아밀로즈의 $D_h$는 urea에 더 큰 영향을 받는 것으로 생각된다. 1-Butanol의 경우 전분 분자의 $D_h$를 증가시켰지만 주목할 만한 경향은 관찰하지 못하였다. 또한, 전분의 아밀로즈 함량과 전분 분자의 $D_h$는 유의적인 상관관계를 보였으며, 이를 활용할 경우 전분의 아밀로즈 함량을 예측하는 데 도움이 될 수 있을 것이라고 기대한다.