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Sample records for blue light exposure

  1. Morning and Evening Blue-Enriched Light Exposure Alters Metabolic Function in Normal Weight Adults.

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    Ivy N Cheung

    Full Text Available Increasing evidence points to associations between light-dark exposure patterns, feeding behavior, and metabolism. This study aimed to determine the acute effects of 3 hours of morning versus evening blue-enriched light exposure compared to dim light on hunger, metabolic function, and physiological arousal. Nineteen healthy adults completed this 4-day inpatient protocol under dim light conditions (<20lux. Participants were randomized to 3 hours of blue-enriched light exposure on Day 3 starting either 0.5 hours after wake (n = 9; morning group or 10.5 hours after wake (n = 10; evening group. All participants remained in dim light on Day 2 to serve as their baseline. Subjective hunger and sleepiness scales were collected hourly. Blood was sampled at 30-minute intervals for 4 hours in association with the light exposure period for glucose, insulin, cortisol, leptin, and ghrelin. Homeostatic model assessment of insulin resistance (HOMA-IR and area under the curve (AUC for insulin, glucose, HOMA-IR and cortisol were calculated. Comparisons relative to baseline were done using t-tests and repeated measures ANOVAs. In both the morning and evening groups, insulin total area, HOMA-IR, and HOMA-IR AUC were increased and subjective sleepiness was reduced with blue-enriched light compared to dim light. The evening group, but not the morning group, had significantly higher glucose peak value during blue-enriched light exposure compared to dim light. There were no other significant differences between the morning or the evening groups in response to blue-enriched light exposure. Blue-enriched light exposure acutely alters glucose metabolism and sleepiness, however the mechanisms behind this relationship and its impacts on hunger and appetite regulation remain unclear. These results provide further support for a role of environmental light exposure in the regulation of metabolism.

  2. Evaluation of blue light exposure to beta brainwaves on simulated night driving

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    Purawijaya, Dandri Aly; Fitri, Lulu Lusianti; Suprijanto

    2015-09-01

    Numbers of night driving accident in Indonesia since 2010 are exponentially rising each year with total of loss more than 50 billion rupiah. One of the causes that contribute to night driving accident is drowsiness. Drowsiness is affected by circadian rhythm resulted from the difference of blue light quality and quantity between night and day. Blue light may effect on human physiology through non-visual pathway by suppressing melatonin hormone suppression that influence drowsiness. Meanwhile, the production of hormones and other activities in brain generate bioelectrical activity such as brainwaves and can be recorded using Electroencephalograph (EEG). Therefore, this research objective is to evaluate the effect of blue light exposure to beta brainwave emergence during night driving simulation to a driver. This research was conducted to 4 male subjects who are able to drive and have a legitimate car driving license. The driving simulator was done using SCANIA Truck Driving Simulator on freeform driving mode in dark environment. Subjects drove for total 32 minutes. The data collections were taken in 2 days with 16 minutes for each day. The 16 minutes were divided again into 8 minutes adaptation in dark and 8 minutes for driving either in blue light exposure or in total darkness. While driving the simulation, subjects' brainwaves were recorded using EEG EMOTIV 14 Channels, exposed by LED monochromatic blue light with 160 Lux from source and angle 45o and sat 1 m in front of the screen. Channels used on this research were for visual (O1; O2), cognition (F3; F4; P7; P8), and motor (FC5; FC6). EEG brainwave result was filtered with EEGLab to obtain beta waves at 13 - 30 Hz frequencies. Results showed that beta waves response to blue light varied for each subject. Blue light exposure either increased or decreased beta waves in 2 minutes pattern and maintaining beta waves on cognition and motor area in 3 out of 4 subjects. Meanwhile, blue light exposure did not maintain

  3. In-car nocturnal blue light exposure improves motorway driving: a randomized controlled trial.

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    Jacques Taillard

    Full Text Available Prolonged wakefulness greatly decreases nocturnal driving performance. The development of in-car countermeasures is a future challenge to prevent sleep-related accidents. The aim of this study is to determine whether continuous exposure to monochromatic light in the short wavelengths (blue light, placed on the dashboard, improves night-time driving performance. In this randomized, double-blind, placebo-controlled, cross-over study, 48 healthy male participants (aged 20-50 years drove 400 km (250 miles on motorway during night-time. They randomly and consecutively received either continuous blue light exposure (GOLite, Philips, 468 nm during driving or 2*200 mg of caffeine or placebo of caffeine before and during the break. Treatments were separated by at least 1 week. The outcomes were number of inappropriate line crossings (ILC and mean standard deviation of the lateral position (SDLP. Eight participants (17% complained about dazzle during blue light exposure and were removed from the analysis. Results from the 40 remaining participants (mean age ± SD: 32.9±11.1 showed that countermeasures reduced the number of inappropriate line crossings (ILC (F(2,91.11 = 6.64; p<0.05. Indeed, ILC were lower with coffee (12.51 [95% CI, 5.86 to 19.66], p = 0.001 and blue light (14.58 [CI, 8.75 to 22.58], p = 0.003 than with placebo (26.42 [CI, 19.90 to 33.71]. Similar results were found for SDLP. Treatments did not modify the quality, quantity and timing of 3 subsequent nocturnal sleep episodes. Despite a lesser tolerance, a non-inferior efficacy of continuous nocturnal blue light exposure compared with caffeine suggests that this in-car countermeasure, used occasionally, could be used to fight nocturnal sleepiness at the wheel in blue light-tolerant drivers, whatever their age. More studies are needed to determine the reproducibility of data and to verify if it can be generalized to women.ClinicalTrials.gov NCT01070004.

  4. Repeated exposures to blue light-activated eosin Y enhance inactivation of E. faecalis biofilms, in vitro.

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    Marinic, Karlo; Manoil, Daniel; Filieri, Anna; Wataha, John C; Schrenzel, Jacques; Lange, Norbert; Bouillaguet, Serge

    2015-09-01

    In dentistry, antibacterial photodynamic therapy (a-PDT) has shown promising results for inactivating bacterial biofilms causing carious, endodontic and periodontal diseases. In the current study, we assessed the ability of eosin Y exposed to 3 irradiation protocols at inactivating Enterococcus faecalis biofilms, in vitro. E. faecalis biofilms formed on hydroxyapatite disks were incubated with eosin Y (10-80μM), then activated with blue light using different irradiation protocols. Biofilms exposed to continuous exposure were incubated for 40min before being light-activated for 960 s. For the intermittent exposure, biofilms were exposed 4 times to the light/photosensitizer combination (960 s total) without renewing the photosensitizer. For repeated a-PDT, the same light dose was delivered in a series of 4 irradiation periods separated by dark periods; fresh photosensitizer was added between each light irradiation. After treatment, bacteria were immediately labeled with LIVE/DEAD BacLight Bacterial Viability kit and viability was assessed by flow cytometry (FCM). Results were statistically analyzed using one-way ANOVA and Tukey multiple comparison intervals (α=0.05). The viability of E. faecalis biofilms exposed to 10μM eosin Y, was significantly reduced compared to controls (light only-eosin Y only). After a second exposure to blue light-activated eosin Y, viability significantly decreased from 58% to 12% whereas 6.5% of the bacterial biofilm remained live after a third exposure (p<0.05). Only 3.5% of the bacterial population survived after the fourth exposure. The results of this study indicate that blue light-activated eosin Y can photoinactivate E. faecalis biofilms grown on hydroxyapatite disks. Also, repeated exposures to blue light-activated eosin Y were shown to significantly improve efficacy. Further studies seem warranted to optimize the antibacterial activity of blue light-activated eosin Y on major oral pathogens. Copyright © 2015 Elsevier B.V. All

  5. Exposure to blue wavelength light modulates anterior cingulate cortex activation in response to 'uncertain' versus 'certain' anticipation of positive stimuli.

    Science.gov (United States)

    Alkozei, Anna; Smith, Ryan; Killgore, William D S

    2016-03-11

    Blue wavelength light has been used as an effective treatment for some types of mood disorders and circadian rhythm related sleep problems. We hypothesized that acute exposure to blue wavelength light would directly affect the functioning of neurocircuity implicated in emotion regulation (i.e., ventromedial prefrontal cortex, amygdala, insula, and anterior cingulate cortex [ACC]) during 'certain' and 'uncertain' anticipation of negative and positive stimuli. Thirty-five healthy adults were randomized to receive a thirty-minute exposure to either blue (active) or amber (placebo) light, immediately followed by an emotional anticipation task during functional magnetic resonance imaging (fMRI). In contrast to placebo, participants in the blue light group showed significantly reduced activation within the rostral ACC during 'uncertain' anticipation (i.e., uncertainty regarding whether a positive or negative stimulus would be shown) in comparison to 'certain' anticipation of a positive stimulus. These findings may be explicable in terms of interactions between blue light exposure and the influence of specific neuromodulators on ACC-mediated decision-making mechanisms. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Blue light Exposure And Long-Term Deficits In Visual Function

    Science.gov (United States)

    Clarke, A. M.

    1980-10-01

    During the last 6 months of 1976, the fovea of two trained rhesus monkeys were exposed to a 10 nm bandwidth source, centered at 441 nm, at energy levels representing up to three times that required in the paramacula to cause minimal, ophthalmoscopically visible lesions to appear 48 hours postexposure (30 J/cm2 to 90 J/cm2, 1000 sec). After the acute period, a visual decrement lasting beyond 30 days postexposure occurred only for the 90 J/cm2, 1000 second fovea' exposure; the statistically significant criteria for recognition of the 20/20 (1.0 min of arc) Landolt ring target was not met, although the criteria for the 20/30 (1.5 min of arc) target was continuously met after 33 days of recovery. The animals are still regularly tested in the original protocol for visual acuity, and additionally have been examined for spectral sensitivity and changes in reaction time to the visual stimulus. During the last 6 months of 1979, only the eye originally exposed at the 90 J/cm2 level failed at any test session to meet the recognition criteria for 1.0 min targets, and all eyes met the criteria for 1.5 min targets at every session. This indicates no long-term changes in the visual acuity, ruling out physiologic repair mechanisms operating beyond the first 30 to 60 days postexposure, or long term degenerative changes accumulating after the initial recovery period. Additionally, the spectral sensitivity of the subject exposed to higher levels shows a mild red but no blue deficit for 20/50 (2.5 min) targets compared to the CIE photopic function. At 1.5 min however, the spectral sensitivity would seem to be better fit by a single photopigment curve, centered at 535 nm.

  7. Enhancement of autonomic and psychomotor arousal by exposures to blue wavelength light: importance of both absolute and relative contents of melanopic component.

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    Yuda, Emi; Ogasawara, Hiroki; Yoshida, Yutaka; Hayano, Junichiro

    2017-01-31

    Blue light containing rich melanopsin-stimulating (melanopic) component has been reported to enhance arousal level, but it is unclear whether the determinant of the effects is the absolute or relative content of melanopic component. We compared the autonomic and psychomotor arousal effects of melanopic-enriched blue light of organic light-emitting diode (OLED) with those of OLED lights with lesser absolute amount of melanopic component (green light) and with greater absolute but lesser relative content (white light). Using a ceiling light consisting of 120 panels (55 × 55 mm square) of OLED modules with adjustable color and brightness, we examined the effects of blue, green, and white lights (melanopic photon flux densities, 0.23, 0.14, and 0.38 μmol/m 2 /s and its relative content ratios, 72, 17, and 14%, respectively) on heart rate variability (HRV) during exposures and on the performance of psychomotor vigilance test (PVT) after exposures in ten healthy subjects with normal color vision. For each of the three colors, five consecutive 10-min sessions of light exposures were performed in the supine position, interleaved by four 10-min intervals during which 5-min PVT was performed under usual fluorescent light in sitting position. Low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0.40 Hz) power and LF-to-HF ratio (LF/HF) of HRV during light exposures and reaction time (RT) and minor lapse (RT >500 ms) of PVT were analyzed. Heart rate was higher and the HF power reflecting autonomic resting was lower during exposures to the blue light than the green and white lights, while LF/HF did not differ significantly. Also, the number of minor lapse and the variation of reaction time reflecting decreased vigilance were lower after exposures to the blue light than the green light. The effects of blue OLED light for maintaining autonomic and psychomotor arousal levels depend on both absolute and relative contents of melanopic component in the light.

  8. [Occupational exposure of welders to ultraviolet and "blue light" radiation emitted during TIG and MMA welding based on field measurements].

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    Wolska, Agnieszka

    2013-01-01

    The aim of the study was to present the results of welders' occupational exposure to "blue light" and UV radiation carried out at industrial workstations during TIG and MMA welding. Measurements were performed at 13 workstations (TIG welding: 6; MMA welding: 7), at which different welding parameters and materials were used. The radiation level was measured using a wide-range radiometer and a set of detectors, whose spectral responses were adequately fit to particular hazard under study. The measurement points corresponded with the location of eye and hand. The highest values of eye irradiance were found for aluminum TIG welding. Effective irradiance of actinic UV was within the range E(s) = 7.79-37.6 W/m2; UVA total irradiance, E(UVA) = 18-53.1 W/m2 and effective blue-light irradiance E(B) = 35-67 W/m2. The maximum allowance time ranged from 1.7 to 75 s, which means that in some cases even unintentional very short eye exposure can exceed MPE. The influence of welded material and the type of electrode coating on the measured radiation level were evidenced. The exceeded value of MPE for photochemical hazard arising for the eyes and skin was found at all measured workstations. Welders should use appropriately the eye and face protective equipment and avoid direct staring at welding arc when starting an arc-welding operation. Besides, the lack of head and neck skin protection can induce acute and chronic harmful health effects. Therefore, an appropriate wear of personal protective equipment is essential for welders' health.

  9. Occupational exposure of welders to ultraviolet and "blue light" radiation emitted during TIG and MMA welding based on field measuremants

    Directory of Open Access Journals (Sweden)

    Agnieszka Wolska

    2013-02-01

    Full Text Available Background: The aim of the study was to present the results of welders' occupational exposure to "blue light" and UV radiation carried out at industrial workstations during TIG and MMA welding. Materials and methods: Measurements were performed at 13 workstations (TIG welding: 6; MMA welding: 7, at which different welding parameters and materials were used. The radiation level was measured using a wide-range radiometer and a set of detectors, whose spectral responses were adequately fit to particular hazard under study. The measurement points corresponded with the location of eye and hand. Results: The highest values of eye irradiance were found for aluminum TIG welding. Effective irradiance of actinic UV was within the range Es = 7.79-37.6 W/m2; UVA total irradiance, EUVA = 18-53.1 W/m2 and effective blue-light irradiance EB = 35-67 W/m2. The maximum allowance time ranged from 1.7 to 75 s, which means that in some cases even unintentional very short eye exposure can exceed MPE. Conclusions: The influence of welded material and the type of electrode coating on the measured radiation level were evidenced. The exceeded value of MPE for photochemical hazard arising for the eyes and skin was found at all measured workstations. Welders should use appropriately the eye and face protective equipment and avoid direct staring at welding arc when starting an arcwelding operation. Besides, the lack of head and neck skin protection can induce acute and chronic harmful health effects. Therefore, an appropriate wear of personal protective equipment is essential for welders' health. Med Pr 2013;64(1:69–82

  10. Blue Light Protects Against Temporal Frequency Sensitive Refractive Changes.

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    Rucker, Frances; Britton, Stephanie; Spatcher, Molly; Hanowsky, Stephan

    2015-09-01

    Time spent outdoors is protective against myopia. The outdoors allows exposure to short-wavelength (blue light) rich sunlight, while indoor illuminants can be deficient at short-wavelengths. In the current experiment, we investigate the role of blue light, and temporal sensitivity, in the emmetropization response. Five-day-old chicks were exposed to sinusoidal luminance modulation of white light (with blue; N = 82) or yellow light (without blue; N = 83) at 80% contrast, at one of six temporal frequencies: 0, 0.2, 1, 2, 5, 10 Hz daily for 3 days. Mean illumination was 680 lux. Changes in ocular components and corneal curvature were measured. Refraction, eye length, and choroidal changes were dependent on the presence of blue light (P light, refraction did not change across frequencies (mean change -0.24 [diopters] D), while in the absence of blue light, we observed a hyperopic shift (>1 D) at high frequencies, and a myopic shift (>-0.6 D) at low frequencies. With blue light there was little difference in eye growth across frequencies (77 μm), while in the absence of blue light, eyes grew more at low temporal frequencies and less at high temporal frequencies (10 vs. 0.2 Hz: 145 μm; P light. Illuminants rich in blue light can protect against myopic eye growth when the eye is exposed to slow changes in luminance contrast as might occur with near work.

  11. Blue light-induced oxidative stress in live skin.

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    Nakashima, Yuya; Ohta, Shigeo; Wolf, Alexander M

    2017-07-01

    Skin damage from exposure to sunlight induces aging-like changes in appearance and is attributed to the ultraviolet (UV) component of light. Photosensitized production of reactive oxygen species (ROS) by UVA light is widely accepted to contribute to skin damage and carcinogenesis, but visible light is thought not to do so. Using mice expressing redox-sensitive GFP to detect ROS, blue light could produce oxidative stress in live skin. Blue light induced oxidative stress preferentially in mitochondria, but green, red, far red or infrared light did not. Blue light-induced oxidative stress was also detected in cultured human keratinocytes, but the per photon efficacy was only 25% of UVA in human keratinocyte mitochondria, compared to 68% of UVA in mouse skin. Skin autofluorescence was reduced by blue light, suggesting flavins are the photosensitizer. Exposing human skin to the blue light contained in sunlight depressed flavin autofluorescence, demonstrating that the visible component of sunlight has a physiologically significant effect on human skin. The ROS produced by blue light is probably superoxide, but not singlet oxygen. These results suggest that blue light contributes to skin aging similar to UVA. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Biological behaviour of buccal cells exposed to blue light

    International Nuclear Information System (INIS)

    Gritsch, Kerstin; Ponsonnet, Laurence; Schembri, Catherine; Farge, Pierre; Pourreyron, Laurence; Grosgogeat, Brigitte

    2008-01-01

    Blue light is used in dental practise to cure resin-based materials, but the path of the light often includes oral tissues such as gingival tissues. While adverse effects of blue light exposure on cells - such as retina cells - are well known, few studies have investigated the impact of blue light exposure on oral cells. The aim of the present in vitro study was to assess the biological effects of blue light emitted by two dental curing devices (a plasma-arc and a light-emitting diode curing unit) on human gingival fibroblasts. Light intensities and light-induced temperature rise were respectively measured with a radiometer and a thermocouple. Cellular response to blue light exposure was assessed by the observation of cell morphology (scanning electron microscopy) and the estimation of cell mitochondrial activity (MTT assay). Light intensities measured at the clinical distance were 488 ± 42 mW/cm 2 for the plasma-arc unit and ranged from 61 ± 5 to 140 ± 16 mW/cm 2 for the light-emitting diodes unit, according to the curing program used. The highest temperature rise was 0.5 and 3.5 deg. C for exposure to the plasma-arc light and to the light-emitting diodes light, respectively. Results showed no differences between exposed- and non-exposed cells in regards to cell morphology. However, cells exposed to blue light presented an increased mitochondrial activity compared to control cells (non-exposed), and mostly those exposed to plasma-arc light

  13. Combatant eye protection: an introduction to the blue light hazard

    Science.gov (United States)

    Lattimore, Morris R.

    2016-05-01

    Emerging evidence of metabolic vulnerability to visible blue light is vitally important, as it is indicative of a scalable threshold effect. Added stressors (e.g., increased altitude or contact lens wear) could shift the wavelength effects toward a more damaging clinical picture. Recent reports have indicated rod photo-pigment damage resulting from solar blue-light exposures, adversely affecting unaided night vision, a militarily important performance decrement. The activation wavelength for the daily synchronous setting of the Circadian Clock, which regulates the synchronization of all hormonal and organ systems throughout the body, falls within this blue light perceptual range.

  14. [The dangers of blue light: True story!].

    Science.gov (United States)

    Renard, G; Leid, J

    2016-05-01

    The dangers of the blue light are the object of numerous publications, for both the scientific community and the general public. The new prolific development of light sources emitting potentially toxic blue light (415-455nm) ranges from LED (Light Emitting Diodes) lamps for interior lighting to television screens, computers, digital tablets and smartphones using OLED (Organic Light Emitting Diode) or AMOLED (Active-Matrix Organic Light Emitting Diode) technology. First we will review some technical terms and the main characteristics of light perceived by the human eye. Then we will discuss scientific proof of the toxicity of blue light to the eye, which may cause cataract or macular degeneration. Analysis of the light spectra of several light sources, from natural light to LED lamps, will allow us to specify even better the dangers related to each light source. LED lamps, whether used as components for interior lighting or screens, are of concern if they are used for extended viewing times and at short distance. While we can protect ourselves from natural blue light by wearing colored glasses which filter out, on both front and back surfaces, the toxic wavelengths, it is more difficult to protect oneself from LED lamps in internal lighting, the use of which should be restricted to "white warmth" lamps (2700K). As far as OLED or AMOLED screens are concerned, the only effective protection consists of using them occasionally and only for a short period of time. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Blue light inhibits the growth of B16 melanoma cells

    International Nuclear Information System (INIS)

    Ohara, Masayuki; Katoh, Osamu; Watanabe, Hiromitsu

    2002-01-01

    Although a number of studies have been carried out to examine the biological effects of radiation and ultraviolet radiation (UV), little is known concerning the effects of visible light. In the present study, exposure of B16 melanoma cells to blue light (wavelength 470 nm, irradiance 5.7 mW/cm 2 ) from a light-emitting diode (LED) inhibited cell growth in proportion to the period of exposure, with no increase observed in the number of dead cells. The number of B16 melanoma colonies that formed after exposure to blue light for 20 min was only slightly less than that in non-exposed controls, but the colony size as assessed by the area covered by colonies and cell counts per colony were markedly decreased. The percentages of G0/G1 and G2/M phase cells were markedly increased, with a reduction in S phase cells as determined by flow cytometry after exposure to blue light. Furthermore, analysis of the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into DNA also showed a reduction in the percentage of S phase cells after exposure. These results indicate that blue light exerts cytostatic effects, but not a cytocidal action, on B16 melanoma cells. (author)

  16. Blue light inhibits the growth of B16 melanoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, Masayuki; Katoh, Osamu; Watanabe, Hiromitsu [Hiroshima Univ. (Japan). Research Inst. for Radiation Biology and Medicine; Kawashima, Yuzo [Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima (Japan)

    2002-05-01

    Although a number of studies have been carried out to examine the biological effects of radiation and ultraviolet radiation (UV), little is known concerning the effects of visible light. In the present study, exposure of B16 melanoma cells to blue light (wavelength 470 nm, irradiance 5.7 mW/cm{sup 2}) from a light-emitting diode (LED) inhibited cell growth in proportion to the period of exposure, with no increase observed in the number of dead cells. The number of B16 melanoma colonies that formed after exposure to blue light for 20 min was only slightly less than that in non-exposed controls, but the colony size as assessed by the area covered by colonies and cell counts per colony were markedly decreased. The percentages of G0/G1 and G2/M phase cells were markedly increased, with a reduction in S phase cells as determined by flow cytometry after exposure to blue light. Furthermore, analysis of the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into DNA also showed a reduction in the percentage of S phase cells after exposure. These results indicate that blue light exerts cytostatic effects, but not a cytocidal action, on B16 melanoma cells. (author)

  17. Cellular effects of halogen blue light from dental curing unit

    International Nuclear Information System (INIS)

    Trosic, I.; Pavicic, I.; Jukic, S.

    2008-01-01

    Full text: Halogen curing lights are the most frequently used polymerization source in dental offices. Light-cured bonding systems have become increasingly popular among clinicians because they offer a number of advantages over self-cured adhesives. The effort to increase polymerization quality releases the commercially available high power light density dental curing units. Emitted visible blue light belongs to the range of nonionizing radiation. Common concern in both, patients and dentist grows with regard to the unfavorable effects on the pulp tissue. The aim of study was to evaluate the time and dose dependence effect of halogen light curing unit (Elipar TriLight, ESPE Dental AG, Germany) at the disposed condition modes in vitro. A quartz-tungsten-halogen light source emits radiation of the wavelengths between 400 and 515 nm. This halogen blue light source operates in the three illumination modes, medium (M), exponential (E) and standard (S), and five illumination times. The total irradiance or the light intensity was measured by the light intensity control area on the control panel of device and mean light intensity given by manufacturer was 800 m W/cm 2 . Continuous culture of V79 cells was illuminated in triplicate. The influence of medium mode (M), exponential (E) and standard (S) illumination during 20, 40 and 80 sec on the cell viability, colony forming ability and proliferation of V79 cell culture was investigated. Trypan blue exclusion test was used to determine cell viability, both, in the treated and control cell samples. Colony forming ability was assessed for each exposure time and mode by colony count on post-exposure day 7. Cell proliferation was determined by cell counts for each time and mode of exposure during five post-exposure days. Statistical difference were determined at p<0.05 (Statistica 7.0, StatSoft Inc., USA). Viability of cells was not affected by blue light in view of exposure time and modes. Regardless to exposure or illumination

  18. Blue light-mediated inactivation of Enterococcus faecalis in vitro.

    Science.gov (United States)

    Pileggi, Giorgio; Wataha, John C; Girard, Myriam; Grad, Iwona; Schrenzel, Jacques; Lange, Norbert; Bouillaguet, Serge

    2013-05-01

    In dentistry, residual infection remains a major cause of failure after endodontic treatment; many of these infections involve Enterococcus faecalis. In the current study, we explored the possibility that blue light activated photosensitizers could be used, in principle, to inactivate this microbe as an adjunct disinfection strategy for endodontic therapy. Three blue light absorbing photosensitizers, eosin-Y, rose bengal, and curcumin, were tested on E. faecalis grown in planktonic suspensions or biofilms. Photosensitizers were incubated for 30 min with bacteria then exposed to blue light (450-500 nm) for 240 s. Sodium hypochlorite (3%) was used as a control. After 48 h, the viability of E. faecalis was estimated by measuring colony-forming units post-exposure vs. untreated controls (CFU/mL). Blue light irradiation alone did not alter E. faecalis viability. For planktonic cultures, blue light activated eosin-Y (5 μM), rose bengal (1 μM), or curcumin (5 μM) significantly (pcurcumin of 100, 10, and 10 μM respectively, completely suppressed E. faecalis viability (p<0.05). Although the current results are limited to an in vitro model, they support further exploration of blue light activated antimicrobials as an adjunct therapy in endodontic treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Antimicrobial blue light inactivation of Neisseria gonorrhoeae

    Science.gov (United States)

    Wang, Ying; Gu, Ying; Dai, Tianhong

    2018-02-01

    Neisseria gonorrhoeae is a human-adapted, gram-negative diplococcus that infects human reproductive tracts and causes gonorrhea, a sexually transmitted disease, resulting in discharge and inflammation at the urethra, cervix, pharynx, or rectum. Over the years, N. gonorrhoeae has developed resistance to nearly every drug ever used to treat it, including sulfonamides, penicillin, tetracycline, and fluoroquinolones. Drug-resistant N. gonorrhoeae is now considered by the Centers for Disease Control and Prevention (CDC) as an urgent threat. The present study aimed to evaluate the efficacy of antimicrobial blue light (aBL) at 405 and 470 nm for inactivating N. gonorrhoeae and reveal the mechanism of action. Our results showed that an exposure of 45 J/cm2 aBL at 405 nm reduced the bacterial CFU by 7.16-log10. When the aBL exposure was increased to 54 J/cm2, eradication of bacterial CFU was achieved. When the bacteria were exposed to aBL at 470 nm, 3-log10 reduction of CFU was observed at an aBL exposure of higher than 126 J/cm2. Absorption and fluorescence spectroscopic analyses revealed the presence of endogenous porphyrins and flavins in N. gonorrhoeae cells. The present study indicated that aBL is a potential strategy to control N. gonorrhoeae infections. Endogenous porphyrins play a vital role in the killing effects of aBL. In vivo experiments are ongoing in our laboratory to treat genital tract infections in mice using aBL and explore the potential clinical applications.

  20. Blue-light emitting triazolopyridinium and triazoloquinolinium salts

    KAUST Repository

    Carboni, Valentina; Su, Xin; Qian, Hai; Aprahamian, Ivan; Credi, Alberto

    2017-01-01

    Compounds that emit blue light are of interest for applications that include optoelectronic devices and chemo/biosensing and imaging. The design and synthesis of small organic molecules that can act as high-efficiency deep-blue-light emitters

  1. Blue-light filtering alters angiogenic signaling in human retinal pigmented epithelial cells culture model.

    Science.gov (United States)

    Vila, Natalia; Siblini, Aya; Esposito, Evangelina; Bravo-Filho, Vasco; Zoroquiain, Pablo; Aldrees, Sultan; Logan, Patrick; Arias, Lluis; Burnier, Miguel N

    2017-11-02

    Light exposure and more specifically the spectrum of blue light contribute to the oxidative stress in Age-related macular degeneration (AMD). The purpose of the study was to establish whether blue light filtering could modify proangiogenic signaling produced by retinal pigmented epithelial (RPE) cells under different conditions simulating risk factors for AMD. Three experiments were carried out in order to expose ARPE-19 cells to white light for 48 h with and without blue light-blocking filters (BLF) in different conditions. In each experiment one group was exposed to light with no BLF protection, a second group was exposed to light with BLF protection, and a control group was not exposed to light. The ARPE-19 cells used in each experiment prior to light exposure were cultured for 24 h as follows: Experiment 1) Normoxia, Experiment 2) Hypoxia, and Experiment 3) Lutein supplemented media in normoxia. The media of all groups was harvested after light exposure for sandwich ELISA-based assays to quantify 10 pro-angiogenic cytokines. A significant decrease in angiogenin secretion levels and a significant increase in bFGF were observed following light exposure, compared to dark conditions, in both normoxia and hypoxia conditions. With the addition of a blue light-blocking filter in normoxia, a significant increase in angiogenin levels was observed. Although statistical significance was not achieved, blue light filters reduce light-induced secretion of bFGF and VEGF to near normal levels. This trend is also observed when ARPE-19 cells are grown under hypoxic conditions and when pre-treated with lutein prior to exposure to experimental conditions. Following light exposure, there is a decrease in angiogenin secretion by ARPE-19 cells, which was abrogated with a blue light - blocking filter. Our findings support the position that blue light filtering affects the secretion of angiogenic factors by retinal pigmented epithelial cells under normoxic, hypoxic, and lutein

  2. Blue light phototherapy for Psoriasis from a systems biology perspective

    NARCIS (Netherlands)

    Félix Garza, Z.C.; Liebmann, J.; Hilbers, P.A.J.; Riel, van N.A.W.

    2014-01-01

    This work analyses the effect of UV-free blue light (BL) irradiation of the skin using mathematical modelling. Prior research has shown that blue light reduces the proliferation of keratinocytes by inducing their differentiation, and causes apoptosis of lymphocytes. The effects of blue light on

  3. Ocular exposure to ultraviolet and visible radiation from light sources

    International Nuclear Information System (INIS)

    Hietanen, M.

    1992-01-01

    Exposure of the eyes to UV radiation and blue light of artificial light sources and the sun was evaluated. A spectroradiometer was used to determine the spectral irradiance at 1 nm intervals from 250 to 800 nm. Various groups of workers are at risk of ocular over-exposure to optical radiation, outdoor workers maintenance personnel of bright light source as and wear eye-protectors with effective filtering of UV radiation and blue light. (author)

  4. Blue Light Enhances Bacterial Clearance and Reduces Organ Injury During Sepsis.

    Science.gov (United States)

    Lewis, Anthony J; Zhang, Xianghong; Griepentrog, John E; Yuan, Du; Collage, Richard D; Waltz, Paul K; Angus, Derek C; Zuckerbraun, Brian S; Rosengart, Matthew R

    2018-05-04

    The physiology of nearly all mammalian organisms are entrained by light and exhibit circadian rhythm. The data derived from animal studies show that light influences immunity, and these neurophysiologic pathways are maximally entrained by the blue spectrum. Here, we hypothesize that bright blue light reduces acute kidney injury by comparison with either bright red or standard, white fluorescent light in mice subjected to sepsis. To further translational relevance, we performed a pilot clinical trial of blue light therapy in human subjects with appendicitis. Laboratory animal research, pilot human feasibility trial. University basic science laboratory and tertiary care hospital. Male C57BL/6J mice, adult (> 17 yr) patients with acute appendicitis. Mice underwent cecal ligation and puncture and were randomly assigned to a 24-hour photoperiod of bright blue, bright red, or ambient white fluorescent light. Subjects with appendicitis were randomized to receive postoperatively standard care or standard care plus high-illuminance blue light. Exposure to bright blue light enhanced bacterial clearance from the peritoneum, reduced bacteremia and systemic inflammation, and attenuated the degree of acute kidney injury. The mechanism involved an elevation in cholinergic tone that augmented tissue expression of the nuclear orphan receptor REV-ERBα and occurred independent of alterations in melatonin or corticosterone concentrations. Clinically, exposure to blue light after appendectomy was feasible and reduced serum interleukin-6 and interleukin-10 concentrations. Modifying the spectrum of light may offer therapeutic utility in sepsis.

  5. Clinical and histological effects of blue light on normal skin.

    NARCIS (Netherlands)

    Kleinpenning, M.M.; Smits, T.; Frunt, M.H.A.; Erp, P.E.J. van; Kerkhof, P.C.M. van de; Gerritsen, R.M.

    2010-01-01

    INTRODUCTION: Phototherapy with visible light is gaining interest in dermatological practice. Theoretically, blue light could induce biological effects comparable to ultraviolet A (UVA) radiation. OBJECTIVES: To study the effects of blue light on normal skin in terms of photodamage, skin ageing and

  6. High-luminosity blue and blue-green gallium nitride light-emitting diodes.

    Science.gov (United States)

    Morkoç, H; Mohammad, S N

    1995-01-06

    Compact and efficient sources of blue light for full color display applications and lighting eluded and tantalized researchers for many years. Semiconductor light sources are attractive owing to their reliability and amenability to mass manufacture. However, large band gaps are required to achieve blue color. A class of compound semiconductors formed by metal nitrides, GaN and its allied compounds AIGaN and InGaN, exhibits properties well suited for not only blue and blue-green emitters, but also for ultraviolet emitters and detectors. What thwarted engineers and scientists from fabricating useful devices from these materials in the past was the poor quality of material and lack of p-type doping. Both of these obstacles have recently been overcome to the point where highluminosity blue and blue-green light-emitting diodes are now available in the marketplace.

  7. Effects of blue light and caffeine on mood.

    Science.gov (United States)

    Ekström, Johan G; Beaven, C Martyn

    2014-09-01

    Both short wavelength (blue) light and caffeine have been studied for their mood enhancing effects on humans. The ability of blue light to increase alertness, mood and cognitive function via non-image forming neuropathways has been suggested as a non-pharmacological countermeasure for depression across a range of occupational settings. This experimental study compared blue light and caffeine and aimed to test the effects of blue light/placebo (BLU), white light/240-mg caffeine (CAF), blue light/240-mg caffeine (BCAF) and white light/placebo (PLA), on mood. A randomised, controlled, crossover design study was used, in a convenience population of 20 healthy volunteers. The participants rated their mood on the Swedish Core Affect Scales (SCAS) prior to and after each experimental condition to assess the dimensions of valence and activation. There was a significant main effect of light (p = 0.009), and the combination of blue light and caffeine had clear positive effects on core effects (ES, ranging from 0.41 to 1.20) and global mood (ES, 0.61 ± 0.53). The benefits of the combination of blue light and caffeine should be further investigated across a range of applications due to the observed effects on the dimensions of arousal, valence and pleasant activation.

  8. Phototropin 1 and dim-blue light modulate the red light de-etiolation response.

    Science.gov (United States)

    Wang, Yihai; M Folta, Kevin

    2014-01-01

    Light signals regulate seedling morphological changes during de-etiolation through the coordinated actions of multiple light-sensing pathways. Previously we have shown that red-light-induced hypocotyl growth inhibition can be reversed by addition of dim blue light through the action of phototropin 1 (phot1). Here we further examine the fluence-rate relationships of this blue light effect in short-term (hours) and long-term (days) hypocotyl growth assays. The red stem-growth inhibition and blue promotion is a low-fluence rate response, and blue light delays or attenuates both the red light and far-red light responses. These de-etiolation responses include blue light reversal of red or far-red induced apical hook opening. This response also requires phot1. Cryptochromes (cry1 and cry2) are activated by higher blue light fluence-rates and override phot1's influence on hypocotyl growth promotion. Exogenous application of auxin transport inhibitor naphthylphthalamic acid abolished the blue light stem growth promotion in both hypocotyl growth and hook opening. Results from the genetic tests of this blue light effect in auxin transporter mutants, as well as phytochrome kinase substrate mutants indicated that aux1 may play a role in blue light reversal of red light response. Together, the phot1-mediated adjustment of phytochrome-regulated photomorphogenic events is most robust in dim blue light conditions and is likely modulated by auxin transport through its transporters.

  9. Phototherapy with blue and green mixed-light is as effective against unconjugated jaundice as blue light and reduces oxidative stress in the Gunn rat model.

    Science.gov (United States)

    Uchida, Yumiko; Morimoto, Yukihiro; Uchiike, Takao; Kamamoto, Tomoyuki; Hayashi, Tamaki; Arai, Ikuyo; Nishikubo, Toshiya; Takahashi, Yukihiro

    2015-07-01

    Phototherapy using blue light-emitting diodes (LED) is effective against neonatal jaundice. However, green light phototherapy also reduces unconjugated jaundice. We aimed to determine whether mixed blue and green light can relieve jaundice with minimal oxidative stress as effectively as either blue or green light alone in a rat model. Gunn rats were exposed to phototherapy with blue (420-520 nm), filtered blue (FB; 440-520 nm without 1.00), respectively. Blue plus green phototherapy is as effective as blue phototherapy and it attenuates irradiation-induced oxidative stress. Combined blue and green spectra might be effective against neonatal hyperbilirubinemia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Blue and Green Light-Induced Phototropism in Arabidopsis thaliana and Lactuca sativa L. Seedlings 1

    Science.gov (United States)

    Steinitz, Benjamin; Ren, Zhangling; Poff, Kenneth L.

    1985-01-01

    Exposure time-response curves for blue and green light-induced phototropic bending in hypocotyls of Arabidopsis thaliana (L.) Heynh. and Lactuca sativa L. seedlings are presented. These seedlings show significant phototropic sensitivity up to 540 to 550 nanometers. Since wave-lengths longer than 560 nanometers do not induce phototropic bending, it is suggested that the response to 510 to 550 nanometers light is mediated by the specific blue light photoreceptor of phototropism. We advise care in the use of green `safelights' for studies of phototropism. PMID:16664021

  11. Degradation of phosphorescent blue organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Chien-Shu [Department of Electrical Engineering and Information Technology, Technical University of Braunschweig (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Steinbacher, Frank [Department of Materials Science VI, University of Erlangen-Nuernberg (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Krause, Ralf; Hunze, Arvid [Siemens AG, CT MM 1, Erlangen (Germany); Kowalsky, Wolfgang [Department of Electrical Engineering and Information Technology, Technical University of Braunschweig (Germany)

    2009-07-01

    Development of phosphorescent materials has significantly improved the efficiency of organic light-emitting diodes (OLEDs). By using efficient red, green and blue phosphorescent emitter materials high efficient white OLEDs can be achieved. However, due to low stability of blue phosphorescent materials the lifetime of phosphorescent white OLEDs remains an issue. As a result, degradation of blue phosphorescent materials needs to be further investigated and improved. In this work, blue OLED devices based on the phosphorescent emitter FIrpic were investigated. Single-carrier hole-only as well as electron-only devices were fabricated. For investigation of degradation process the devices were stressed with electrical current and UV-light to study the impact of charge carriers as well as excitons and exciton-polaron quenching on the stability of the blue dye.

  12. Blue-light emitting triazolopyridinium and triazoloquinolinium salts

    KAUST Repository

    Carboni, Valentina

    2017-01-27

    Compounds that emit blue light are of interest for applications that include optoelectronic devices and chemo/biosensing and imaging. The design and synthesis of small organic molecules that can act as high-efficiency deep-blue-light emitters in the solid state and can be easily processed from solutions represents a significant challenge. Herein we present the preparation and photophysical, photochemical and electrochemical properties of a series of triazolopyridinium and triazoloquinolinium compounds. The compounds are soluble in water or polar organic solvents and exhibit photoluminescence in the blue region of the spectrum in fluid solution, in the solid state and in a frozen matrix.

  13. Photochemical eradication of methicillin-resistant Staphylococcus aureus by blue light activation of riboflavin.

    Science.gov (United States)

    Makdoumi, Karim; Goodrich, Ray; Bäckman, Anders

    2017-08-01

    To compare elimination of methicillin-resistant Staphylococcus aureus (MRSA) by exposure of blue light alone and with riboflavin. A reference strain of MRSA was cultured and diluted in PBS with and without riboflavin (0.01%). Fifteen microlitre was added on a microscope slide, creating a fluid layer with a thickness of around 400 microns. Both of the bacterial suspensions were exposed to blue light, and the effect between exposure with and without riboflavin was compared. Evaluation involved two different wavelengths (412 and 450 nm) of blue light with a lower (5.4 J/cm 2 ) and higher dose (approximately 28.5 J/cm 2 ). The effect of 412 nm light was also evaluated for a thicker fluid layer (1.17 mm). After exposure, colony-forming units (CFUs) were determined for each solution. All measurements were repeated eight times. The reductions in bacteria were similar for both wavelengths. With riboflavin, a statistically significant elimination was observed for both 412 and 450 nm (p riboflavin than without it. Using the higher dose, CFU reduction was 99% and 98%, respectively, for 412 and 450 nm light. The bactericidal efficacy was high also in the deeper fluid layer (93%, higher dose). Riboflavin enhanced the antibacterial effect on the exposed MRSA strain of blue light for both 412 and 450 nm blue light. This indicates that blue light could be considered for possible implementation in deep corneal infections. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  14. Origin of colour stability in blue/orange/blue stacked phosphorescent white organic light-emitting diodes

    International Nuclear Information System (INIS)

    Kim, Sung Hyun; Jang, Jyongsik; Yook, Kyoung Soo; Lee, Jun Yeob

    2009-01-01

    The origin of colour stability in phosphorescent white organic light-emitting diodes (PHWOLEDs) with a blue/orange/blue stacked emitting structure was studied by monitoring the change in a recombination zone. A balanced recombination zone shift between the blue and the orange light-emitting layers was found to be responsible for the colour stability in the blue/orange/blue stacked PHWOLEDs.

  15. Environmental blue light prevents stress in the fish Nile tilapia

    Directory of Open Access Journals (Sweden)

    Volpato G.L.

    2001-01-01

    Full Text Available The present study aimed to test the effects of blue, green or white light on the stress response of the Nile tilapia, Oreochromis niloticus (L.. Each color was tested on two groups of isolated adult Nile tilapia (8 replicates each: one being subjected to confinement stress, and the other not (control. A different environmental color was imposed on each compartment by covering the light source with cellophane of the respective color (green or blue; no cellophane was used for white light. The intensity of green, white and blue lights was 250, 590 and 250 lux, respectively. Basal plasma cortisol levels were determined for each fish prior to the experimental procedures. The fish were confined by being displaced toward one side of the aquarium using an opaque partition for 1 h both in the morning and the afternoon of the two consecutive days of the test. At the end of this 48-h period, plasma cortisol levels were measured again. Basal cortisol levels (ng/ml were similar for each group (ANOVA, F(2;42 = 0.77, P = 0.47. Thus, plasma cortisol levels were analyzed in terms of variation from their respective basal level. After confinement, plasma cortisol levels were not increased in fish submitted to a blue light environment. Thus, blue light prevents the confinement-induced cortisol response, an effect not necessarily related to light intensity.

  16. Biological effects of blocking blue and other visible light on the mouse retina.

    Science.gov (United States)

    Narimatsu, Toshio; Ozawa, Yoko; Miyake, Seiji; Kubota, Shunsuke; Yuki, Kenya; Nagai, Norihiro; Tsubota, Kazuo

    2014-08-01

    To elucidate the biological effects of blocking fluorescent light on the retina using specific blocking materials. Seven- to 8-week-old BALB/c mice were divided into three groups and placed in one of the three boxes: one blocked ultraviolet and violet wavelengths of light (violet blockade), one blocked ultraviolet, violet, blue and some other visible wavelengths (blue-plus blockade), and one allowed most visible light to pass through (control). They were then exposed to a white fluorescent lamp for 1 h at 5.65E-05 mW/cm(2) /s. After treatment, the electroretinogram, retinal outer nuclear layer thickness and retinal outer segment length were measured. In addition, retinal apoptotic cells were quantified by TdT-mediated dUTP nick-end labelling assay and c-Fos messenger RNA, and protein levels were measured by real-time reverse-transcription polymerase chain reaction and immunoblot analyses, respectively. The blue-plus blockade group retained a significantly better electroretinogram response following light exposure than the control or violet blockade groups. The blue-plus blockade group also exhibited greater outer nuclear layer thickness and greater outer-segment length, and fewer apoptotic cells after light exposure than the other groups. The c-Fos messenger RNA and protein levels were substantially reduced in the blue-plus blockade group and reduced to a lesser extent in the violet blockade group. The blockade of blue plus additional visible wavelengths of light was most effective in protecting the retina from light-induced damage. The blockade of violet light alone was also effective in reducing intracellular molecular responses, but these effects were not sufficient for attenuating retinal degeneration. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  17. Commercial preslaughter blue light ambience for controlling broiler stress and meat qualities

    Directory of Open Access Journals (Sweden)

    Claudia Freitas Barbosa

    2013-10-01

    Full Text Available The objective of this work was to study the effect of blue light diffuser on the broiler stress control by measuring the occurrence of PSE meat just before slaughtering. Birds were divided into the following two groups before slaughter at the point of being hung on shackles: broiler group under low intensity blue light ambience (475, 17-20 lx and control group under white light (550-650nm, 321-332 lx. Birds' stressful conditions were measured by the occurrence of PSE meat. Breast fillets were classified as PSE meat based on pH ( 53.0. The fillet samples in the control group had the following characteristics: pHu=5.77, L* = 54.26 and b*= 6.27. The fillet samples from birds under blue light ambience had the following characteristics: pHu=5.81, L* = 52.86 and b* = 5.22 (p < 0.05. These results revealed that the treatment of blue light ambience just before slaughtering contributed to the alleviation of ante mortem stress of the birds, which was observed by a 14% decrease in the occurrence of PSE meat. Exposure to blue light just before slaughtering was shown to have potential to be used in modern slaughterhouses to offer a comfortable atmosphere, thereby maintaining breast meat quality.

  18. The plasma membrane-associated NADH oxidase of spinach leaves responds to blue light

    Science.gov (United States)

    Morre, D. James; Penel, Claude; Greppin, Hubert; Morre, Dorothy M.

    2002-01-01

    The plasma membrane-associated NADH oxidase (NOX) of spinach leaf disks is characterized by oscillations in activity with a regular period length of ca. 24 min. Within a single population of plants exposed to light at the same time, NOX activities of all plants function synchronously. Exposure of plants transferred from darkness to blue light (495 nm, 2 min, 50 micromoles m-2 s-1) resulted in a complex response pattern but with a new maximum in the rate of NOX activity 36 (24+12) min after illumination and then with maxima in the rate of NOX activity every 24 min thereafter. Transient maxima in NOX activity were observed as well after 9.3 + /- 1.4 and 20.7 +/- 2.1 min. The blue light response differed from the response to red (650 nm, 10 min, 50 micromoles m-2 s-1) or white light where activity maxima were initiated 12 min after the light exposure followed by maxima every 24 min thereafter. Green or yellow light was ineffective. The light response was independent of the time in the 24-min NOX cycle when the light was given. The net effects of blue and red light were ultimately the same with a new maximum in the rate of NOX activity at 12+24=36 min (and every 24 min thereafter), but the mechanisms appear to be distinct.

  19. Blue and ultraviolet-B light photoreceptors in parsley cells

    International Nuclear Information System (INIS)

    Ensminger, P.A.; Schaefer, E.

    1992-01-01

    The authors studied UV-B photoreception in parsley cell cultures with physiological experiments involving temperature shifts and examined the possible role of flavin in blue and UV-B light photo-reception. Cells irradiated with UV-B light (0.5-15 min) at 2 o C have the same fluence requirement for chalcone synthase and flavonoid induction as controls irradiated at 25 o C. This is indicative of a purely photochemical reaction. Cells fed with riboflavin and irradiated with 6 h of UV-containing white light synthesize higher levels of chalcone synthase and flavonoid than unfed controls. This effect did not occur with blue light. These results indicate that flavin-sensitization requires excitation of flavin and the UV-B light photoreceptor. (author)

  20. Blue laser diode (LD) and light emitting diode (LED) applications

    International Nuclear Information System (INIS)

    Bergh, Arpad A.

    2004-01-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography. As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc. Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity. Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Blue laser diode (LD) and light emitting diode (LED) applications

    Energy Technology Data Exchange (ETDEWEB)

    Bergh, Arpad A [Optoelectronics Industry Development Association (OIDA), 1133 Connecticut Avenue, NW, Suite 600, Washington, DC 20036-4329 (United States)

    2004-09-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography. As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc. Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity. Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Capsule Design for Blue Light Therapy against Helicobacter pylori.

    Science.gov (United States)

    Li, Zhangyong; Ren, Binbin; Tan, Haiyan; Liu, Shengrong; Wang, Wei; Pang, Yu; Lin, Jinzhao; Zeng, Chen

    2016-01-01

    A photo-medical capsule that emits blue light for Helicobacter pylori treatment was described in this paper. The system consists of modules for pH sensing and measuring, light-emitting diode driver circuit, radio communication and microcontroller, and power management. The system can differentiate locations by monitoring the pH values of the gastrointestinal tract, and turn on and off the blue light according to the preset range of pH values. Our experimental tests show that the capsule can operate in the effective light therapy mode for more than 32 minutes and the wireless communication module can reliably transmit the measured pH value to a receiver located outside the body.

  3. Supporting Information Blue and White light electroluminescence in ...

    Indian Academy of Sciences (India)

    Administrator

    Blue and White light electroluminescence in a multilayer OLED using a new Aluminium complex. Pabitra K. Nayak a. , Neeraj Agarwal a. , Farman Ali a. , Meghan P. Patankar b. , K. L.. Narasimhan b. *, N. Periasamy a. *. 1. Department of Chemical Sciences,. 2. Department of Condensed Matter Physics and. Materials ...

  4. Photo Inactivation of Streptococcus mutans Biofilm by Violet-Blue light.

    Science.gov (United States)

    Gomez, Grace F; Huang, Ruijie; MacPherson, Meoghan; Ferreira Zandona, Andrea G; Gregory, Richard L

    2016-09-01

    Among various preventive approaches, non-invasive phototherapy/photodynamic therapy is one of the methods used to control oral biofilm. Studies indicate that light at specific wavelengths has a potent antibacterial effect. The objective of this study was to determine the effectiveness of violet-blue light at 380-440 nm to inhibit biofilm formation of Streptococcus mutans or kill S. mutans. S. mutans UA159 biofilm cells were grown for 12-16 h in 96-well flat-bottom microtiter plates using tryptic soy broth (TSB) or TSB with 1 % sucrose (TSBS). Biofilm was irradiated with violet-blue light for 5 min. After exposure, plates were re-incubated at 37 °C for either 2 or 6 h to allow the bacteria to recover. A crystal violet biofilm assay was used to determine relative densities of the biofilm cells grown in TSB, but not in TSBS, exposed to violet-blue light. The results indicated a statistically significant (P mutans growth and reduce the formation of S. mutans biofilm. This in vitro study demonstrated that violet-blue light has the capacity to inhibit S. mutans biofilm formation. Potential clinical applications of light therapy in the future remain bright in preventing the development and progression of dental caries.

  5. Blue and white light emission from zinc oxide nanoforests

    Directory of Open Access Journals (Sweden)

    Nafisa Noor

    2015-12-01

    Full Text Available Blue and white light emission is observed when high voltage stress is applied using micrometer-separated tungsten probes across a nanoforest formed of ZnO nanorods. The optical spectrum of the emitted light consistently shows three fine peaks with very high amplitude in the 465–485 nm (blue range, corresponding to atomic transitions of zinc. Additional peaks with smaller amplitudes in the 330–650 nm range and broad spectrum white light is observed depending on the excitation conditions. The spatial and spectral distribution of the emitted light, with pink–orange regions identifying percolation paths in some cases and high intensity blue and white light with center to edge variations in others, indicate that multiple mechanisms lead to light emission. Under certain conditions, the tungsten probe tips used to make electrical contact with the ZnO structures melt during the excitation, indicating that the local temperature can exceed 3422 °C, which is the melting temperature of tungsten. The distinct and narrow peaks in the optical spectra and the abrupt increase in current at high electric fields suggest that a plasma is formed by application of the electrical bias, giving rise to light emission via atomic transitions in gaseous zinc and oxygen. The broad spectrum, white light emission is possibly due to the free electron transitions in the plasma and blackbody radiation from molten silicon. The white light may also arise from the recombination through multiple defect levels in ZnO or due to the optical excitation from solid ZnO. The electrical measurements performed at different ambient pressures result in light emission with distinguishable differences in the emission properties and I–V curves, which also indicate that the dielectric breakdown of ZnO, sublimation, and plasma formation processes are the underlying mechanisms.

  6. Investigation of phosphorescent blue organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Chien-Shu [Department of Electrical Engineering and Information Technology, Technical University of Braunschweig (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Krause, Ralf [Department of Materials Science VI, University of Erlangen-Nuernberg (Germany); Siemens AG, CT MM 1, Erlangen (Germany); Kozlowski, Fryderyk; Hunze, Arvid [Siemens AG, CT MM 1, Erlangen (Germany); Kowalsky, Wolfgang [Department of Electrical Engineering and Information Technology, Technical University of Braunschweig (Germany)

    2008-07-01

    Recently, rapid development of phosphorescent materials has significantly improved the efficiency of organic light emitting diodes (OLEDs). By using efficient phosphorescent emitter materials white OLEDs with high power efficiency values could be demonstrated. But especially blue phosphorescent devices, due to stability issues, need to be further investigated und optimized. In this work, blue OLED devices based on the phosphorescent emitter FIrpic were investigated. Single-carrier hole-only as well as electron-only devices were fabricated and characterized to study the impact of charge carriers on device performance.

  7. [Study on the safety of blue light leak of LED].

    Science.gov (United States)

    Shen, Chong-Yu; Xu, Zheng; Zhao, Su-Ling; Huang, Qing-Yu

    2014-02-01

    In this paper, the blue light properties of LED illumination devices have been investigated. Against the status quo of China's LED lighting, we measured the spectrum component of LED lamps and analyzed the photobiological safety under the current domestic and international standards GB/T 20145-2006/CIE S009/E: 2002 and IEC62471: 2006 standards as well as CTL-0744_2009-laser resolution, which provides the reference to the manufacture of LED lighting lamps as well as related safety standards and laws. If the radiance intensity of blue light in LED is lower than 100 W x m(-2) x Sr(-1), there is no harm to human eyes. LEDs will not cause harm to human eyes under normal use, but we should pay attention to the protection of special populations (children), and make sure that they avoid looking at a light source for a long time. The research has found that the blue-rich lamps can affect the human rule of work and rest, and therefore, the LED lamps with color temperature below 4 000 K and color rendering index of 80 are suitable for indoor use. At the same time, the lamps with different parameters should be selected according to the different distances.

  8. Blue Light Emitting Polyphenylene Dendrimers with Bipolar Charge Transport Moieties

    Directory of Open Access Journals (Sweden)

    Guang Zhang

    2016-10-01

    Full Text Available Two light-emitting polyphenylene dendrimers with both hole and electron transporting moieties were synthesized and characterized. Both molecules exhibited pure blue emission solely from the pyrene core and efficient surface-to-core energy transfers when characterized in a nonpolar environment. In particular, the carbazole- and oxadiazole-functionalized dendrimer (D1 manifested a pure blue emission from the pyrene core without showing intramolecular charge transfer (ICT in environments with increasing polarity. On the other hand, the triphenylamine- and oxadiazole-functionalized one (D2 displayed notable ICT with dual emission from both the core and an ICT state in highly polar solvents. D1, in a three-layer organic light emitting diode (OLED by solution processing gave a pure blue emission with Commission Internationale de l’Éclairage 1931 CIE xy = (0.16, 0.12, a peak current efficiency of 0.21 cd/A and a peak luminance of 2700 cd/m2. This represents the first reported pure blue dendrimer emitter with bipolar charge transport and surface-to-core energy transfer in OLEDs.

  9. Blue Light Emitting Polyphenylene Dendrimers with Bipolar Charge Transport Moieties.

    Science.gov (United States)

    Zhang, Guang; Auer-Berger, Manuel; Gehrig, Dominik W; Blom, Paul W M; Baumgarten, Martin; Schollmeyer, Dieter; List-Kratochvil, E J W; Müllen, Klaus

    2016-10-20

    Two light-emitting polyphenylene dendrimers with both hole and electron transporting moieties were synthesized and characterized. Both molecules exhibited pure blue emission solely from the pyrene core and efficient surface-to-core energy transfers when characterized in a nonpolar environment. In particular, the carbazole- and oxadiazole-functionalized dendrimer ( D1 ) manifested a pure blue emission from the pyrene core without showing intramolecular charge transfer (ICT) in environments with increasing polarity. On the other hand, the triphenylamine- and oxadiazole-functionalized one ( D2 ) displayed notable ICT with dual emission from both the core and an ICT state in highly polar solvents. D1 , in a three-layer organic light emitting diode (OLED) by solution processing gave a pure blue emission with Commission Internationale de l'Éclairage 1931 CIE xy = (0.16, 0.12), a peak current efficiency of 0.21 cd/A and a peak luminance of 2700 cd/m². This represents the first reported pure blue dendrimer emitter with bipolar charge transport and surface-to-core energy transfer in OLEDs.

  10. Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert?

    Directory of Open Access Journals (Sweden)

    Sarah Laxhmi Chellappa

    Full Text Available BACKGROUND: Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance. METHODS: Sixteen healthy young men were studied in a balanced cross-over design with light exposure of 3 different light settings (compact fluorescent lamps with light of 40 lux at 6500K and at 2500K and incandescent lamps of 40 lux at 3000K during 2 h in the evening. RESULTS: Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task, but not in tasks associated with executive function (Paced Visual Serial Addition Task. This cognitive improvement was strongly related with attenuated salivary melatonin levels, particularly for the light condition at 6500K. CONCLUSIONS: Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.

  11. Evidence for dark repair of far ultraviolet light damage in the blue-green alga, Gloeocapsa alpicola

    International Nuclear Information System (INIS)

    Williams, E.; Lambert, J.; O'Brien, P.; Houghton, J.A.

    1979-01-01

    The inactivating effect of far UV light on the unicellular blue-green alga Gloeocapsa alpicola could be totally reversed by exposure to blue light immediately after irradiation. However, if the irradiated cells were held in the dark before exposure to blue light, reversal became progressively less efficient, and almost disappeared after 60-80 h holding. Caffeine and acriflavine inhibited loss of photoreversibility, suggesting an involvement of excision functions. Chloramphenicol and rifampicin slightly increased the rate of loss of photoreversibility, indicating that inducible functions play only a minor role. Split UV dose experiments indicated that light-dependent repair remained operational during dark liquid holding. These results provide preliminary evidence for dark repair in G. alpicola. (author)

  12. Do blue-light filtering intraocular lenses affect visual function?

    Science.gov (United States)

    Lavric, Alenka; Pompe, Manca Tekavcic

    2014-11-01

    To study different aspects of visual function, macular changes, and subjective differences between the eye with an ultraviolet (UV) and blue-light filtering intraocular lens (IOL) and the fellow eye with a UV-light filtering IOL. Thirty patients (60 eyes) with senile cataract had both cataracts extracted, and an IOL was implanted at least 2 years before clinical evaluation. In one eye, AcrySof SA60AT (a UV-light filtering IOL) was implanted, whereas in the contralateral eye, AcrySof IQ SN60WF (a blue-light filtering IOL) was implanted. Each patient underwent visual acuity testing, color vision testing (Ishihara and Farnsworth-Munsell 100-hue tests), and contrast sensitivity (CS) testing. The macula was evaluated with optical coherence tomography and with clinical examination. Patients were asked if they noted any difference between the implanted IOLs concerning visual impression. Subjective visual quality was evaluated using the National Eye Institute Visual Functioning Questionnaire. There was a borderline statistically significant difference in the mean best-corrected visual acuity (p = 0.05). As regards color vision, no significant changes in Ishihara and Farnsworth-Munsell 100-hue error scores were detected between both eyes (p = 0.48 and p = 0.59, respectively). Analysis of CS showed no significant difference between the groups at any spatial frequency. There were also no statistically significant differences in central macular thickness and total macular volume between the two IOL groups (p = 0.72 and p = 0.61, respectively). In both IOL groups, three eyes developed an epiretinal membrane, and six eyes developed early signs of age-related macular degeneration. This study showed no significant effects of a blue-light filtering IOL on visual acuity and no influence on color perception and CS. After more than 2 years, there were no significant differences in macular changes between the IOL groups. Clinical evidence of the effect of a blue-light filtering IOL on

  13. Effects of blue or violet light on the inactivation of Staphylococcus aureus by riboflavin-5'-phosphate photolysis.

    Science.gov (United States)

    Wong, Tak-Wah; Cheng, Chien-Wei; Hsieh, Zong-Jhe; Liang, Ji-Yuan

    2017-08-01

    The light sensitive compound riboflavin-5'-phosphate (or flavin mononucleotide, FMN) generates reactive oxygen species (ROS) upon photo-irradiation. FMN is required by all flavoproteins because it is a cofactor of biological blue-light receptors. The photochemical effects of FMN after irradiation by blue or violet light on the inactivation of Staphylococcus aureus strains, including a methicillin-resistant strain (MRSA), were investigated in this study. Upon blue- or violet-light photo-treatment, FMN was shown to inactivate S. aureus due to the generated ROS. Effective bacterial inactivation can be achieved by FMN photolysis without an exogenous electron provider. Inactivation rates of 94.9 and 95.2% in S. aureus and MRSA, respectively, can be reached by blue light irradiation (2.0mW/cm 2 ) with 120μM FMN for 120min. A lower FMN concentration and a shorter time are required to reach similar effects by violet light irradiation. Inactivation rates of 96.3 and 97.0% in S. aureus and MRSA, respectively, can be reached by violet light irradiation (1.0mW/cm 2 ) with 30μM FMN for 30min. The sensitivity of the inherent photosensitizers is lower under blue-light irradiation. A long exposure photolytic treatment of FMN by blue light is required to inactivate S. aureus. Violet light was found to be more efficient in S. aureus inactivation at the same radiant intensity. FMN photolysis with blue or violet light irradiation enhanced the inactivation rates of S. aureus and MRSA. FMN photochemical treatment could be a supplemental technique in hygienic decontamination processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Ultraviolet radiation and blue-light emissions from spotlights incorporating tungsten halogen lamps

    CERN Document Server

    MacKinlay, Alistair F; Whillock, M J

    1989-01-01

    This report summarises measurements of the ultraviolet radiation and blue-light emissions from eleven 'desk-top' tungsten halogen (quartz) lamps and one 'floor-standing' tungsten halogen (quartz) lamp available in the UK. Values of occupational hazard weighted and erythemally weighted ultraviolet radiation irradiance and measurements and relevant calculations of blue-light hazards are presented. It is concluded that the safety design of some desk-top tungsten halogen lamps is inadequate to prevent unnecessary exposure of the skin to potentially harmful ultraviolet radiation. It is recommended that all tungsten halogen lamps should have sufficient filtration to reduce their ultraviolet emissions to an acceptably low level. As long as the comfort aversion responses of the eye are respected, direct viewing of the lamps examined should not constitute a retinal hazard.

  15. Ultraviolet radiation and blue-light emissions from spotlights incorporating tungsten halogen lamps

    International Nuclear Information System (INIS)

    McKinlay, A.F.; Whillock, M.J.; Meulemans, C.C.E.

    1989-07-01

    This report summarises measurements of the ultraviolet radiation and blue-light emissions from eleven 'desk-top' tungsten halogen (quartz) lamps and one 'floor-standing' tungsten halogen (quartz) lamp available in the UK. Values of occupational hazard weighted and erythemally weighted ultraviolet radiation irradiance and measurements and relevant calculations of blue-light hazards are presented. It is concluded that the safety design of some desk-top tungsten halogen lamps is inadequate to prevent unnecessary exposure of the skin to potentially harmful ultraviolet radiation. It is recommended that all tungsten halogen lamps should have sufficient filtration to reduce their ultraviolet emissions to an acceptably low level. As long as the comfort aversion responses of the eye are respected, direct viewing of the lamps examined should not constitute a retinal hazard. (author)

  16. Blue-enriched office light competes with natural light as a zeitgeber.

    Science.gov (United States)

    Vetter, Céline; Juda, Myriam; Lang, Dieter; Wojtysiak, Andreas; Roenneberg, Till

    2011-09-01

    Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the "zeitgeber" light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.

  17. Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer

    DEFF Research Database (Denmark)

    Herbst, Kristina; Sander, Birgit; Milea, Dan

    2011-01-01

    In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at two selected wavelengths (660 and 470 nm......, we have developed a novel prototype of color pupillometer which demonstrates good repeatability in evoking and recording the pupillary response to a bright blue and red light stimulus....

  18. Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer

    DEFF Research Database (Denmark)

    Herbst, Kristina; Sander, Birgit; Milea, Dan

    2011-01-01

    In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at two selected wavelengths (660 and 470¿nm......, we have developed a novel prototype of color pupillometer which demonstrates good repeatability in evoking and recording the pupillary response to a bright blue and red light stimulus....

  19. Suppressed speckle contrast of blue light emission out of white lamp with phosphors excited by blue laser diodes for high-brightness lighting applications

    Science.gov (United States)

    Kinoshita, Junichi; Ikeda, Yoshihisa; Takeda, Yuji; Ueno, Misaki; Kawasaki, Yoji; Matsuba, Yoshiaki; Heike, Atsushi

    2012-11-01

    The speckle contrast of blue light emission out of high-brightness white lamps using phosphors excited by InGaN/GaN blue laser diodes is evaluated as a measure of coherence. As a result, speckle contrast of as low as 1.7%, the same level as a blue light emitting diode, is obtained. This implies that the original blue laser light can be converted into incoherent light through lamp structures without any dynamic mechanisms. This unique speckle-free performance is considered to be realized by multiple scattering inside the lamp structure, the multi-longitudinal mode operation of the blue laser diodes, and the use of multiple laser diodes. Such almost-incoherent white lamps can be applied for general lighting without any nuisance of speckle noise and should be categorized as lamps rather than lasers in terms of laser safety regulation.

  20. Blue light induced reactive oxygen species from flavin mononucleotide and flavin adenine dinucleotide on lethality of HeLa cells.

    Science.gov (United States)

    Yang, Ming-Yeh; Chang, Chih-Jui; Chen, Liang-Yü

    2017-08-01

    Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm 2 (=0.52mW/cm 2 irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD 50 ) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model: implications for prophylaxis and treatment of combat-related wound infections.

    Science.gov (United States)

    Zhang, Yunsong; Zhu, Yingbo; Gupta, Asheesh; Huang, Yingying; Murray, Clinton K; Vrahas, Mark S; Sherwood, Margaret E; Baer, David G; Hamblin, Michael R; Dai, Tianhong

    2014-06-15

    In this study, we investigated the utility of antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model. A bioluminescent clinical isolate of multidrug-resistant A. baumannii was obtained. The susceptibility of A. baumannii to blue light (415 nm)-inactivation was compared in vitro to that of human keratinocytes. Repeated cycles of sublethal inactivation of bacterial by blue light were performed to investigate the potential resistance development of A. baumannii to blue light. A mouse model of third degree burn infected with A. baumannii was developed. A single exposure of blue light was initiated 30 minutes after bacterial inoculation to inactivate A. baumannii in mouse burns. It was found that the multidrug-resistant A. baumannii strain was significantly more susceptible than keratinocytes to blue light inactivation. Transmission electron microscopy revealed blue light-induced ultrastructural damage in A. baumannii cells. Fluorescence spectroscopy suggested that endogenous porphyrins exist in A. baumannii cells. Blue light at an exposure of 55.8 J/cm(2) significantly reduced the bacterial burden in mouse burns. No resistance development to blue light inactivation was observed in A. baumannii after 10 cycles of sublethal inactivation of bacteria. No significant DNA damage was detected in mouse skin by means of a skin TUNEL assay after a blue light exposure of 195 J/cm(2). © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure

    Directory of Open Access Journals (Sweden)

    Maria Angeles Bonmati-Carrion

    2014-12-01

    Full Text Available Currently, in developed countries, nights are excessively illuminated (light at night, whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD, including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.

  3. Plant responses to UV and blue light: biochemical and genetic approaches

    International Nuclear Information System (INIS)

    Jenkins, G.I.; Christie, J.M.; Fuglevand, G.; Long, J.C.; Jackson, J.A.

    1995-01-01

    UV and blue light control many aspects of plant growth and development. It is evident that several different photoreceptors mediate responses to UV and blue light, and there are reports of the functional and biochemical characterisation of a putative photoreceptor for phototropism and of the functional and molecular characterisation of the CRY1 photoreceptor, encoded by the Arabidopsis HY4 gene. The CRY1 photoreceptor mediates extension growth and gene expression responses to UV-A/blue light presumably through different or branching signal transduction pathways. Progress has been made in cell physiological and biochemical studies of UV/blue light signal transduction, but much remains to be done to relate candidate UV/blue signal transduction events to particular photoreceptors and responses. The application of a genetic approach in Arabidopsis has been responsible for many advances in understanding UV/blue responses, but further UV-B, UV-A and blue light response mutants need to be isolated. (author)

  4. Blue-Light Therapy following Mild Traumatic Brain Injury: Effects on White Matter Water Diffusion in the Brain

    Directory of Open Access Journals (Sweden)

    Sahil Bajaj

    2017-11-01

    Full Text Available Mild traumatic brain injury (mTBI is a common and often inconspicuous wound that is frequently associated with chronic low-grade symptoms and cognitive dysfunction. Previous evidence suggests that daily blue wavelength light therapy may be effective at reducing fatigue and improving sleep in patients recovering from mTBI. However, the effects of light therapy on recovering brain structure remain unexplored. In this study, we analyzed white matter diffusion properties, including generalized fractional anisotropy, and the quantity of water diffusion in isotropic (i.e., isotropic diffusion and anisotropic fashion (i.e., quantitative anisotropy, QA for fibers crossing 11 brain areas known to be significantly affected following mTBI. Specifically, we investigated how 6 weeks of daily morning blue light exposure therapy (compared to an amber-light placebo condition impacted changes in white matter diffusion in individuals with mTBI. We observed a significant impact of the blue light treatment (relative to the placebo on the amount of water diffusion (QA for multiple brain areas, including the corpus callosum, anterior corona radiata, and thalamus. Moreover, many of these changes were associated with improvements in sleep latency and delayed memory. These findings suggest that blue wavelength light exposure may serve as one of the potential non-pharmacological treatments for facilitating structural and functional recovery following mTBI; they also support the use of QA as a reliable neuro-biomarker for mTBI therapies.

  5. Blue light irradiation-induced oxidative stress in vivo via ROS generation in rat gingival tissue.

    Science.gov (United States)

    Yoshida, Ayaka; Shiotsu-Ogura, Yukako; Wada-Takahashi, Satoko; Takahashi, Shun-suke; Toyama, Toshizo; Yoshino, Fumihiko

    2015-10-01

    It has been reported that oxidative stress with reactive oxygen species (ROS) generation is induced by blue light irradiation to a living body. Only limited research has been reported in dental field on the dangers of blue light, mostly focusing on cytotoxicity associated with heat injury of dental pulp. We thus performed an in vivo study on oral tissue exposed to blue light. ROS generated upon blue light irradiation of flavin adenine dinucleotide were measured by electron spin resonance spectroscopy. After blue light irradiation, the palatal gingiva of Wistar rats were isolated. Collected samples were subjected to biochemical analysis of lipid peroxidation and glutathione. Singlet oxygen was generated by blue light irradiation, but was significantly quenched in an N-acetyl-L-cysteine (NAC) concentration-dependent manner. Blue light significantly accelerated oxidative stress and increased the oxidized glutathione levels in gingival tissue. These effects were also inhibited by NAC pre-administration. The results suggest that blue light irradiation at clinical levels of tooth bleaching treatment may enhance lipid peroxidation by the induction of oxidative stress and the consumption of a significant amount of intracellular glutathione. In addition, NAC might be an effective supplement for the protection of oral tissues against blue light irradiation-induced oxidative damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Blue fluorescent organic light emitting diodes with multilayered graphene anode

    International Nuclear Information System (INIS)

    Hwang, Joohyun; Choi, Hong Kyw; Moon, Jaehyun; Shin, Jin-Wook; Joo, Chul Woong; Han, Jun-Han; Cho, Doo-Hee; Huh, Jin Woo; Choi, Sung-Yool; Lee, Jeong-Ik; Chu, Hye Yong

    2012-01-01

    As an innovative anode for organic light emitting devices (OLEDs), we have investigated graphene films. Graphene has importance due to its huge potential in flexible OLED applications. In this work, graphene films have been catalytically grown and transferred to the glass substrate for OLED fabrications. We have successfully fabricated 2 mm × 2 mm device area blue fluorescent OLEDs with graphene anodes which showed 2.1% of external quantum efficiency at 1000 cd/m 2 . This is the highest value reported among fluorescent OLEDs using graphene anodes. Oxygen plasma treatment on graphene has been found to improve hole injections in low voltage regime, which has been interpreted as oxygen plasma induced work function modification. However, plasma treatment also increases the sheet resistance of graphene, limiting the maximum luminance. In summary, our works demonstrate the practical possibility of graphene as an anode material for OLEDs and suggest a processing route which can be applied to various graphene related devices.

  7. Stomatal Blue Light Response Is Present in Early Vascular Plants.

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-10-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K(+) accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum. © 2015 American Society of Plant Biologists. All Rights Reserved.

  8. Blue light induced free radicals from riboflavin in degradation of crystal violet by microbial viability evaluation.

    Science.gov (United States)

    Liang, Ji-Yuan; Yuann, Jeu-Ming P; Hsie, Zong-Jhe; Huang, Shiuh-Tsuen; Chen, Chiing-Chang

    2017-09-01

    Crystal violet (CV) is applied in daily use mainly as a commercial dye and antimicrobial agent. Waste water containing CV may affect aquatic ecosystems. Riboflavin, also known as vitamin B 2 , is non-toxic and an essential vitamin required for the functions of the human body. Riboflavin is photosensitive to UV and visible light in terms of generating reactive oxygen species. This study investigated the potential application of blue light on riboflavin, so as to come up with an effective way of degrading CV during its treatment. Photosensitivity of CV leading to degradation in the presence of riboflavin was investigated by light intensity, exposure time, and irradiation dosage. The degradation of CV during riboflavin photolysis treatment was studied by a UV/vis spectrometry and chromatography. The effects of CV degradation on microbial viability are relevant when considering the influences on the ecosystem. This study proved that riboflavin photochemical treatment with blue light degrades CV dye by ROS formation. The riboflavin photolysis-treated CV solution appeared to be transparent during conformational transformations of the CV that was rearranged by free radical species generated from riboflavin photolysis. After riboflavin photolysis, colony-forming units (CFUs) were determined for each CV solution. CFU preservation was 85.2% for the CV dissolved riboflavin solution treated with blue light irradiation at 2.0mW/cm 2 for 120min. Degradation of CV by riboflavin photochemical procedures can greatly reduce antimicrobial ability and serve as an environmental friendly waste water treatment method. Our results presented here concerning riboflavin photolysis in degradation of CV provide a novel technique, and a simple and safe practice for environmental decontamination processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. A comparison of blue light and caffeine effects on cognitive function and alertness in humans.

    Science.gov (United States)

    Beaven, C Martyn; Ekström, Johan

    2013-01-01

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.

  10. A comparison of blue light and caffeine effects on cognitive function and alertness in humans.

    Directory of Open Access Journals (Sweden)

    C Martyn Beaven

    Full Text Available The alerting effects of both caffeine and short wavelength (blue light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.

  11. Blue Light Emitting Diodes for Optical Stimulation of Quartz in Retrospective Dosimetry and Dating (invited paper)

    International Nuclear Information System (INIS)

    Botter-Jensen, L.; Duller, G.A.T.; Murray, A.S.; Banerjee, D.

    1999-01-01

    Recently developed blue light emitting diodes (LEDs) for the optical stimulation of quartz for use in routine optically stimulated luminescence (OSL) dating and retrospective dosimetry have been tested. For similar power densities, it was found that the higher energy light provided by the blue LEDs (470 nm) gives order of magnitude greater rate of stimulation in quartz than that from conventional blue-green light filtered from a halogen lamp. A practical blue LED OSL configuration is described. From comparisons of OSL decay curves produced by green and blue light sources, and by examination of the dependence of the blue LED OSL on preheat temperature, it is deduced that there is no evidence that the blue LEDs stimulate deep traps in a different manner from broadband filtered light. It is concluded that blue LEDs offer a practical alternative to existing stimulation sources. They have the significant advantages that the life-time is indefinite, and the output can be controlled electronically; this allows the power to be readily controlled by software. Unlike a filtered light source, there are no electromechanical parts, and the switch on/off times are about 10 times faster than a shutter. Finally, preliminary results from ramping the blue light power output with time are demonstrated. It is shown that this technique enables the separation of OSL components with differing stimulation rates. (author)

  12. [AOR characterization and zoning: a dosimeter for blue light].

    Science.gov (United States)

    Dario, R; Uva, J; Di Lecce, V; Quarto, A

    2011-01-01

    The paper presents the results obtained thanks to an innovative experimental device for the assessment of artificial optical radiation (AOR) exposure in workplace. This . device was developed by 'Politecnico di Bari-DIASS'. The wearable personal dosimeter has three sensors: one is used for measuring head position/movement, therefore there is a color light sensor to determine the AOR and finally there is a video camera to localize sources. Our system is connected to a netbook via USB cable that allows one to obtain the real and extimated value of worker's exposure, also with "augmented reality". The aim of this paper is realizing work place safety zoning for the classifacation of not only specific dangerous areas through the analysis of overlapping information from the device.

  13. Blue light emitting diodes for optical stimulation of quartz in retrospective dosimetry and dating

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Duller, G.A.T.; Murray, A.S.

    1999-01-01

    Recently developed blue light emitting diodes (LEDs) for the optical stimulation of quartz for use in routine optically stimulated luminescence (OSL) dating and retrospective dosimetry have been tested. For similar power densities, it was found that the higher energy light provided by the blue LE......, preliminary results from ramping the blue light power output with time are demonstrated. It is shown that this technique enables the separation of OSL components with differing stimulation rates.......Recently developed blue light emitting diodes (LEDs) for the optical stimulation of quartz for use in routine optically stimulated luminescence (OSL) dating and retrospective dosimetry have been tested. For similar power densities, it was found that the higher energy light provided by the blue LEDs...... (470 nm) gives order of magnitude greater rate of stimulation in quartz than that from conventional blue-green light filtered from a halogen lamp. A practical blue LED OSL configuration is described. From comparisons of OSL decay curves produced by green and blue light sources, and by examination...

  14. Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Wang, Yucheng; Dai, Tianhong; Gu, Ying

    2016-10-01

    Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

  15. Histone Deacetylase HDA-2 Regulates Trichoderma atroviride Growth, Conidiation, Blue Light Perception, and Oxidative Stress Responses.

    Science.gov (United States)

    Osorio-Concepción, Macario; Cristóbal-Mondragón, Gema Rosa; Gutiérrez-Medina, Braulio; Casas-Flores, Sergio

    2017-02-01

    various environments, fungi constantly sense and respond to potentially threatening external factors, such as light. In particular, UV light can damage biomolecules by producing free-radical reactions, in most cases involving reactive oxygen species (ROS). In T. atroviride, conidiation is essential for its survival, which is induced by light and mechanical injury. Notably, conidia are typically used as the inoculum in the field during biocontrol. Therefore, understanding the linkages between responses to light and exposure to ROS in T. atroviride is of major basic and practical relevance. Here, the histone deacetylase-encoding gene hda-2 is induced by light and ROS, and its product regulates growth, conidiation, blue light perception, and oxidative stress responses. Copyright © 2017 American Society for Microbiology.

  16. Efficacy of antimicrobial 405 nm blue-light for inactivation of airborne bacteria

    Science.gov (United States)

    Dougall, Laura R.; Anderson, John G.; Timoshkin, Igor V.; MacGregor, Scott J.; Maclean, Michelle

    2018-02-01

    Airborne transmission of infectious organisms is a considerable concern within the healthcare environment. A number of novel methods for `whole room' decontamination, including antimicrobial 405 nm blue light, are being developed. To date, research has focused on its effects against surface-deposited contamination; however, it is important to also establish its efficacy against airborne bacteria. This study demonstrates evidence of the dose-response kinetics of airborne bacterial contamination when exposed to 405 nm light and compares bacterial susceptibility when exposed in three different media: air, liquid and surfaces. Bacterial aerosols of Staphylococcus epidermidis, generated using a 6-Jet Collison nebulizer, were introduced into an aerosol suspension chamber. Aerosolized bacteria were exposed to increasing doses of 405 nm light, and air samples were extracted from the chamber using a BioSampler liquid impinger, with viability analysed using pour-plate culture. Results have demonstrated successful aerosol inactivation, with a 99.1% reduction achieved with a 30 minute exposure to high irradiance (22 mWcm-2) 405 nm light (P=0.001). Comparison to liquid and surface exposures proved bacteria to be 3-4 times more susceptible to 405 nm light inactivation when in aerosol form. Overall, results have provided fundamental evidence of the susceptibility of bacterial aerosols to antimicrobial 405 nm light treatment, which offers benefits in terms of increased safety for human exposure, and eradication of microbes regardless of antibiotic resistance. Such benefits provide advantages for a number of applications including `whole room' environmental decontamination, in which reducing levels of airborne bacteria should reduce the number of infections arising from airborne contamination.

  17. Phosphorous Diffuser Diverged Blue Laser Diode for Indoor Lighting and Communication

    KAUST Repository

    Chi, Yu-Chieh; Hsieh, Dan-Hua; Lin, Chung-Yu; Chen, Hsiang-Yu; Huang, Chia-Yen; He, Jr-Hau; Ooi, Boon S.; DenBaars, Steven P.; Nakamura, Shuji; Kuo, Hao-Chung; Lin, Gong-Ru

    2015-01-01

    An advanced light-fidelity (Li-Fi) system based on the blue Gallium nitride (GaN) laser diode (LD) with a compact white-light phosphorous diffuser is demonstrated for fusing the indoor white-lighting and visible light communication (VLC

  18. Circadian phase, dynamics of subjective sleepiness and sensitivity to blue light in young adults complaining of a delayed sleep schedule.

    Science.gov (United States)

    Moderie, Christophe; Van der Maren, Solenne; Dumont, Marie

    2017-06-01

    To assess factors that might contribute to a delayed sleep schedule in young adults with sub-clinical features of delayed sleep phase disorder. Two groups of 14 young adults (eight women) were compared: one group complaining of a delayed sleep schedule and a control group with an earlier bedtime and no complaint. For one week, each subject maintained a target bedtime reflecting their habitual sleep schedule. Subjects were then admitted to the laboratory for the assessment of circadian phase (dim light melatonin onset), subjective sleepiness, and non-visual light sensitivity. All measures were timed relative to each participant's target bedtime. Non-visual light sensitivity was evaluated using subjective sleepiness and salivary melatonin during 1.5-h exposure to blue light, starting one hour after target bedtime. Compared to control subjects, delayed subjects had a later circadian phase and a slower increase of subjective sleepiness in the late evening. There was no group difference in non-visual sensitivity to blue light, but we found a positive correlation between melatonin suppression and circadian phase within the delayed group. Our results suggest that a late circadian phase, a slow build-up of sleep need, and an increased circadian sensitivity to blue light contribute to the complaint of a delayed sleep schedule. These findings provide targets for strategies aiming to decreasing the severity of a sleep delay and the negative consequences on daytime functioning and health. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Blue light cystoscopy with hexylaminolevulinate: Our 7 years experience

    Directory of Open Access Journals (Sweden)

    Vito Lacetera

    2017-03-01

    Full Text Available Aim: The objective of the present study is to evaluate the diagnostic accuracy of hexylaminolevulinate (HAL blue light cystoscopy compared with standard white light cystoscopy (WLC in daily practice. Materials and methods: An observational, comparative, controlled (within patient study was carried out at our Center. 61 consecutive patients with suspected or confirmed bladder cancer were recruited for the study from January 2008 until January 2015. Patients with suspected bladder cancer (positive cytology with negative WLC or history of previous high-grade NMIBC or CIS were included in the study. Biopsies/resection of each positive lesion/suspicious areas were always taken after the bladder was inspected under WLC and BLC. Diagnoses of bladder tumor or CIS were considered as positive results, and the presence of normal urothelium in the biopsy specimen as negative result. Results: 61 BLC were performed. 15/61 (24.5% with suspected initial diagnosis of NMIBC and 46/61 (75.5% with a history of high-risk non-muscle invasive bladder cancer (NMIBC. We performed a total of 173 biopsies/TURBT of suspicious areas: 129 positive only to the BLC and 44 both positive to WLC and BLC. 84/173 biopsies/TURBT were positive for cancer. All 84 NMIBC were positive to the BLC, while 35/84 were positive to the WLC with a sensitivity of BLC and WLC respectively of 100% and 41.7%. Sensitivity of WLC for highgrade NMIBC and CIS was 34.1% and 39% respectively while sensitivity of BLC for high-grade NMIBC and CIS was 100%. The specificity of the WLC was 79.9% compared to 48.5% of the BLC. The positive predictive value of BLC and WLC were respectively 48% (95% CI: 0.447-0.523 and 79% (95% CI: 0.856-0.734. Conclusions: Our data confirm those reported in the literature: BLC increases the detection rate of NMIBC particularly in high risk patients (history of CIS or high grade. BLC is a powerful diagnostic tool in the diagnosis of bladder cancer if malignancy is suspected

  20. Homogeneous photosensitized degradation of pharmaceuticals by using red light LED as light source and methylene blue as photosensitizer

    NARCIS (Netherlands)

    Ye, Y.; Bruning, H.; Yntema, D.; Mayer, M.; Rijnaarts, H.

    2017-01-01

    Research on employing advanced oxidation processes (AOPs) for pharmaceuticals removal is gaining interests. However, detrimental effects of background water constituents in complex water matrices are limiting their implementation. In this study, we report red light induced methylene blue

  1. Blue Light for Enhancing Alertness in Space Missions

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the final year of a directed research project that had reduced aims due to an unexpected funding reduction. The goal is to study the efficacy of blue or...

  2. Sensitivity of Seven Diverse Species to Blue and Green Light: Interactions with Photon Flux.

    Directory of Open Access Journals (Sweden)

    M Chase Snowden

    Full Text Available Despite decades of research, the effects of spectral quality on plant growth, and development are not well understood. Much of our current understanding comes from studies with daily integrated light levels that are less than 10% of summer sunlight thus making it difficult to characterize interactions between light quality and quantity. Several studies have reported that growth is increased under fluorescent lamps compared to mixtures of wavelengths from LEDs. Conclusions regarding the effect of green light fraction range from detrimental to beneficial. Here we report the effects of eight blue and green light fractions at two photosynthetic photon fluxes (PPF; 200 and 500 μmol m-2 s-1; with a daily light integral of 11.5 and 29 mol m-2 d-1 on growth (dry mass, leaf expansion, stem and petiole elongation, and whole-plant net assimilation of seven diverse plant species. The treatments included cool, neutral, and warm white LEDs, and combinations of blue, green and/or red LEDs. At the higher PPF (500, increasing blue light in increments from 11 to 28% reduced growth in tomato, cucumber, and pepper by 22, 26, and 14% respectively, but there was no statistically significant effect on radish, soybean, lettuce or wheat. At the lower PPF (200, increasing blue light reduced growth only in tomato (41%. The effects of blue light on growth were mediated by changes in leaf area and radiation capture, with minimal effects on whole-plant net-assimilation. In contrast to the significant effects of blue light, increasing green light in increments from 0 to 30% had a relatively small effect on growth, leaf area and net assimilation at either low or high PPF. Surprisingly, growth of three of the seven species was not reduced by a treatment with 93% green light compared to the broad spectrum treatments. Collectively, these results are consistent with a shade avoidance response associated with either low blue or high green light fractions.

  3. Pulsing blue light through closed eyelids: effects on acute melatonin suppression and phase shifting of dim light melatonin onset.

    Science.gov (United States)

    Figueiro, Mariana G; Plitnick, Barbara; Rea, Mark S

    2014-01-01

    Circadian rhythm disturbances parallel the increased prevalence of sleep disorders in older adults. Light therapies that specifically target regulation of the circadian system in principle could be used to treat sleep disorders in this population. Current recommendations for light treatment require the patients to sit in front of a bright light box for at least 1 hour daily, perhaps limiting their willingness to comply. Light applied through closed eyelids during sleep might not only be efficacious for changing circadian phase but also lead to better compliance because patients would receive light treatment while sleeping. Reported here are the results of two studies investigating the impact of a train of 480 nm (blue) light pulses presented to the retina through closed eyelids on melatonin suppression (laboratory study) and on delaying circadian phase (field study). Both studies employed a sleep mask that provided narrowband blue light pulses of 2-second duration every 30 seconds from arrays of light-emitting diodes. The results of the laboratory study demonstrated that the blue light pulses significantly suppressed melatonin by an amount similar to that previously shown in the same protocol at half the frequency (ie, one 2-second pulse every minute for 1 hour). The results of the field study demonstrated that blue light pulses given early in the sleep episode significantly delayed circadian phase in older adults; these results are the first to demonstrate the efficacy and practicality of light treatment by a sleep mask aimed at adjusting circadian phase in a home setting.

  4. Pulsing blue light through closed eyelids: effects on acute melatonin suppression and phase shifting of dim light melatonin onset

    Directory of Open Access Journals (Sweden)

    Figueiro MG

    2014-12-01

    Full Text Available Mariana G Figueiro, Barbara Plitnick, Mark S Rea Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA Abstract: Circadian rhythm disturbances parallel the increased prevalence of sleep disorders in older adults. Light therapies that specifically target regulation of the circadian system in principle could be used to treat sleep disorders in this population. Current recommendations for light treatment require the patients to sit in front of a bright light box for at least 1 hour daily, perhaps limiting their willingness to comply. Light applied through closed eyelids during sleep might not only be efficacious for changing circadian phase but also lead to better compliance because patients would receive light treatment while sleeping. Reported here are the results of two studies investigating the impact of a train of 480 nm (blue light pulses presented to the retina through closed eyelids on melatonin suppression (laboratory study and on delaying circadian phase (field study. Both studies employed a sleep mask that provided narrowband blue light pulses of 2-second duration every 30 seconds from arrays of light-emitting diodes. The results of the laboratory study demonstrated that the blue light pulses significantly suppressed melatonin by an amount similar to that previously shown in the same protocol at half the frequency (ie, one 2-second pulse every minute for 1 hour. The results of the field study demonstrated that blue light pulses given early in the sleep episode significantly delayed circadian phase in older adults; these results are the first to demonstrate the efficacy and practicality of light treatment by a sleep mask aimed at adjusting circadian phase in a home setting. Keywords: circadian phase, dim light melatonin onset, light through closed eyelids, blue light, sleep

  5. Blue lighting accelerates post-stress relaxation: Results of a preliminary study.

    Science.gov (United States)

    Minguillon, Jesus; Lopez-Gordo, Miguel Angel; Renedo-Criado, Diego A; Sanchez-Carrion, Maria Jose; Pelayo, Francisco

    2017-01-01

    Several authors have studied the influence of light on both human physiology and emotions. Blue light has been proved to reduce sleepiness by suppression of melatonin secretion and it is also present in many emotion-related studies. Most of these have a common lack of objective methodology since results and conclusions are based on subjective perception of emotions. The aim of this work was the objective assessment of the effect of blue lighting in post-stress relaxation, in comparison with white lighting, by means of bio-signals and standardized procedures. We conducted a study in which twelve healthy volunteers were stressed and then performed a relaxation session within a chromotherapy room with blue (test group) or white (control group) lighting. We conclude that the blue lighting accelerates the relaxation process after stress in comparison with conventional white lighting. The relaxation time decreased by approximately three-fold (1.1 vs. 3.5 minutes). We also observed a convergence time (3.5-5 minutes) after which the advantage of blue lighting disappeared. This supports the relationship between color of light and stress, and the observations reported in previous works. These findings could be useful in clinical and educational environments, as well as in daily-life context and emerging technologies such as neuromarketing. However, our study must be extended to draw reliable conclusions and solid scientific evidence.

  6. Blue lighting accelerates post-stress relaxation: Results of a preliminary study.

    Directory of Open Access Journals (Sweden)

    Jesus Minguillon

    Full Text Available Several authors have studied the influence of light on both human physiology and emotions. Blue light has been proved to reduce sleepiness by suppression of melatonin secretion and it is also present in many emotion-related studies. Most of these have a common lack of objective methodology since results and conclusions are based on subjective perception of emotions. The aim of this work was the objective assessment of the effect of blue lighting in post-stress relaxation, in comparison with white lighting, by means of bio-signals and standardized procedures. We conducted a study in which twelve healthy volunteers were stressed and then performed a relaxation session within a chromotherapy room with blue (test group or white (control group lighting. We conclude that the blue lighting accelerates the relaxation process after stress in comparison with conventional white lighting. The relaxation time decreased by approximately three-fold (1.1 vs. 3.5 minutes. We also observed a convergence time (3.5-5 minutes after which the advantage of blue lighting disappeared. This supports the relationship between color of light and stress, and the observations reported in previous works. These findings could be useful in clinical and educational environments, as well as in daily-life context and emerging technologies such as neuromarketing. However, our study must be extended to draw reliable conclusions and solid scientific evidence.

  7. Monolithically Integrated Light Feedback Control Circuit for Blue/UV LED Smart Package

    NARCIS (Netherlands)

    Koladouz Esfahani, Z.; Tohidian, M.; van Zeijl, H.W.; Kolahdouz, Mohammadreza; Zhang, G.Q.

    2017-01-01

    Given the performance decay of high-power light-emitting diode (LED) chips over time and package condition changes, having a reliable output light for sensitive applications is a point of concern. In this study, a light feedback control circuit, including blue-selective photodiodes, for

  8. Blue lighting decreases the amount of food consumed in men, but not in women.

    Science.gov (United States)

    Cho, Sungeun; Han, Ashley; Taylor, Michael H; Huck, Alexandria C; Mishler, Amanda M; Mattal, Kyle L; Barker, Caleb A; Seo, Han-Seok

    2015-02-01

    Previous research has demonstrated that colors of lighting can modulate participants' motivation to consume the food placed under the lighting. This study was designed to determine whether the colors of lighting can affect the amount of food consumed, in addition to sensory perception of the food. The influence of lighting color was also compared between men and women. One-hundred twelve participants (62 men and 50 women) were asked to consume a breakfast meal (omelets and mini-pancakes) under one of three different lighting colors: white, yellow, and blue. During the test, hedonic impression of the food's appearance, willingness to eat, overall flavor intensity and overall impression of the food, and meal size (i.e., the amount of food consumed) were measured. Blue lighting decreased the hedonic impression of the food's appearance, but not the willingness to eat, compared to yellow and white lighting conditions. The blue lighting significantly decreased the amount consumed in men, but not in women, compared to yellow and white lighting conditions. Overall flavor intensity and overall impression of the food were not significantly different among the three lighting colors. In conclusion, this study provides empirical evidence that the color of lighting can modulate the meal size. In particular, blue lighting can decrease the amount of food eaten in men without reducing their acceptability of the food. Published by Elsevier Ltd.

  9. Spectral effects of light-emitting diodes on plant growth and development: The importance of green and blue light

    Science.gov (United States)

    Cope, K. R.; Bugbee, B.

    2011-12-01

    Light-emitting diodes (LEDs) are an emerging technology for plant growth lighting. Due to their narrow spectral output, colored LEDs provide many options for studying the spectral effects of light on plants. Early on, efficient red LEDs were the primary focus of photobiological research; however, subsequent studies have shown that normal plant growth and development cannot be achieved under red light without blue light supplementation. More recent studies have shown that red and blue (RB) LEDs supplemented with green light increase plant dry mass. This is because green light transmits more effectively through the leaf canopy than red and blue light, thus illuminating lower plant leaves and increasing whole-plant photosynthesis. Red, green and blue (RGB) light can be provided by either a conventional white light source (such as fluorescent lights), a combination of RGB LEDs, or from recently developed white LEDs. White LEDs exceed the efficiency of fluorescent lights and have a comparable broad spectrum. As such, they have the potential to replace fluorescent lighting for growth-chamber-based crop production both on Earth and in space. Here we report the results of studies on the effects of three white LED types (warm, neutral and cool) on plant growth and development compared to combinations of RB and RGB LEDs. Plants were grown under two constant light intensities (200 and 500 μmol m-2 s-1). Temperature, environmental conditions and root-zone environment were uniformly maintained across treatments. Phytochrome photoequilbria and red/far-red ratios were similar among treatments and were comparable to conventional fluorescent lights. Blue light had a significant effect on both plant growth (dry mass gain) and development (dry mass partitioning). An increase in the absolute amount (μmol m-2 s-1) of blue light from 0-80 μmol m-2 s-1 resulted in a decrease in stem elongation, independent of the light intensity. However, an increase in the relative amount (%) of blue

  10. Effects of red and blue LD lights on the growth of lettuce

    International Nuclear Information System (INIS)

    Mori, Y.; Takatsuji, M.; Yasuoka, T.

    2003-01-01

    In this study, Lactuca sativa L. cv. “Red Fire” was cultivated under visible laser diodes (LD) light alone, using red and blue LD for digital versatile discs (DVD). Relative growth rate, photosynthetic rate and vitamin C content were measured, and compared with those obtained using light emitting diodes (LED). When the lettuce was cultivated under LD light, the relative growth rate and net photosynthetic rate were decreased compared to those under LED light. The rates were decreased by 10% and 20% or more under red LD light and under a combination of red and blue LD lights, respectively. However, the vitamin C content was higher when grown under LD light than LED light. Considering the high output and high electrical-to-optical power conversion efficiency of LD, LD are potential light sources for plant cultivation when their prices decrease

  11. Therapeutic effect of turquoise versus blue light with equal irradiance in preterm infants with jaundice

    DEFF Research Database (Denmark)

    Ebbesen, Finn; Madsen, Poul; Støvring, Søren

    2007-01-01

    AIM: To compare the efficiency of turquoise light with that of TL52 blue in treatment of preterm infants with jaundice at the same level of body irradiance. METHODS: Infants with gestational age 28-37 weeks and non-haemolytic hyperbilirubinemia were treated for 24 h with either turquoise light (O......,Z-bilirubin and lumirubin, in infants under turquoise light. This suggests, given equal irradiances, that light in the turquoise spectral range is preferable to the TL52 blue in treatment of newborn jaundiced infants....

  12. The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture.

    Science.gov (United States)

    Yang, Minqi; Ma, Ning; Zhu, Yingying; Su, Ying-Chu; Chen, Qingwei; Hsiao, Fan-Chi; Ji, Yanran; Yang, Chien-Ming; Zhou, Guofu

    2018-03-15

    Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K) alternating with 30-min dim normal light (~5 lux, ~3600 K) three times); continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males) were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures) with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE) and total sleep time (TST). Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

  13. The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture

    Directory of Open Access Journals (Sweden)

    Minqi Yang

    2018-03-01

    Full Text Available Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K alternating with 30-min dim normal light (~5 lux, ~3600 K three times; continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE and total sleep time (TST. Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

  14. Efficient fluorescent red, green, and blue organic light-emitting devices with a blue host of spirobifluorene derivative

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.-H. [Department of Chemical and Material Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China)], E-mail: lerongho@yuntech.edu.tw; Huang, Y.-W.; Wang, Y.-Y. [Department of Chemical and Material Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan (China); Chang, H.-Y. [EChem Hightech CO., LTD, Hsin-Chu Industrial Park, Hu-Kou, Hsin-Chu, Taiwan (China)

    2008-06-02

    Efficient fluorescent blue, green, and red (RGB) organic light-emitting devices (OLEDs) were fabricated using a blue host material of pyrimidine-containing spirobifluorene derivative 2,7-bis[2-(4-tert-butylphenyl)pyrimidine-5-yl]-9,9'-spirobifluorene (TBPSF) doped with blue dye perylene, green dye 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H, 11H-benzo[l] pyrano[6,7,8-ij] quinolizin-11-one (C545T), and red dye 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB), respectively. The brightness and current efficiency of the perylene doped blue device reached 10117 cd/m{sup 2} and 2.97 cd/A. Green emission of the C545T doped device reached 8500 cd/m{sup 2} and 13.0 cd/A. Red emission of the DCJTB doped device can be as high as 9000 cd/m{sup 2} and 2.0 cd/A, respectively. High color purity of the blue (Commission Internationale de L'Eclairage (CIE{sub x,y}) coordinates (CIE, x = 0.27, y = 0.24)), green (CIE, x = 0.19, y = 0.63) and red (CIE, x = 0.62, y = 0.37) emissions were achieved for RGB dyes doped TBPSF OLEDs. High brightness, large current efficiency, and good color purity of TBPSF-based RGB OLEDs were obtained by the configuration optimization device, such as inserting the hole and electron-injection materials, and suitable dopant content and light emitting layer thickness.

  15. The effects of blue-enriched light treatment compared to standard light treatment in seasonal affective disorder

    NARCIS (Netherlands)

    Gordijn, M. C. M.; 't Mannetje, D.; Meesters, Y.

    Background: One of the most frequently investigated hypotheses of the pathophysiology underlying Seasonal Affective Disorder (SAD) is a disturbance of circadian rhythms. Since the circadian system as well as other non-visual effects is especially sensitive to blue light, a new light therapy device

  16. Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits

    NARCIS (Netherlands)

    de Jong, Maaike; Caro, Samuel P.; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E.

    2017-01-01

    Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits (Cyanistes caeruleus) exposed to similar intensities of

  17. A train of blue light pulses delivered through closed eyelids suppresses melatonin and phase shifts the human circadian system

    Directory of Open Access Journals (Sweden)

    Figueiro MG

    2013-10-01

    Full Text Available Mariana G Figueiro, Andrew Bierman, Mark S ReaLighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USAAbstract: A model of circadian phototransduction was published in 2005 to predict the spectral sensitivity of the human circadian system to narrow-band and polychromatic light sources by combining responses to light from the spectral-opponent “blue” versus “yellow” cone bipolar pathway with direct responses to light by the intrinsically photosensitive retinal ganglion cells. In the model, depolarizing “blue” responses, but not hyperpolarizing “yellow” responses, from the “blue” versus “yellow” pathway are combined with the intrinsically photosensitive retinal ganglion cell responses. Intrinsically photosensitive retinal ganglion cell neurons are known to be much slower to respond to light than the cone pathway, so an implication of the model is that periodic flashes of “blue” light, but not “yellow” light, would be effective for stimulating the circadian system. A within-subjects study was designed to test the implications of the model regarding retinal exposures to brief flashes of light. The study was also aimed at broadening the foundation for clinical treatment of circadian sleep disorders by delivering flashing light through closed eyelids while people were asleep. In addition to a dark control night, the eyelids of 16 subjects were exposed to three light-stimulus conditions in the phase delay portion of the phase response curve while they were asleep: (1 2-second flashes of 111 W/m2 of blue (λmax ≈ 480 nm light once every minute for 1 hour, (2 131 W/m2 of green (λmax ≈ 527 nm light, continuously on for 1 hour, and (3 2-second flashes of the same green light once every minute for 1 hour. Inferential statistics showed that the blue flash light-stimulus condition significantly delayed circadian phase and significantly suppressed nocturnal melatonin. The results of this study further our

  18. Blue news update: BODIPY-GTP binds to the blue-light receptor YtvA while GTP does not.

    Directory of Open Access Journals (Sweden)

    Matthias Dorn

    Full Text Available Light is an important environmental factor for almost all organisms. It is mainly used as an energy source but it is also a key factor for the regulation of multiple cellular functions. Light as the extracellular stimulus is thereby converted into an intracellular signal by photoreceptors that act as signal transducers. The blue-light receptor YtvA, a bacterial counterpart of plant phototropins, is involved in the stress response of Bacillus subtilis. The mechanism behind its activation, however, remains unknown. It was suggested based on fluorescence spectroscopic studies that YtvA function involves GTP binding and that this interaction is altered by absorption of light. We have investigated this interaction by several biophysical methods and show here using fluorescence spectroscopy, ITC titrations, and three NMR spectroscopic assays that while YtvA interacts with BODIPY-GTP as a fluorescent GTP analogue originally used for the detection of GTP binding, it does not bind GTP.

  19. Nanostructured High Performance Ultraviolet and Blue Light Emitting Diodes for Solid State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Arto V. Nurmikko; Jung Han

    2007-03-31

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the duration of the contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  20. Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits.

    Science.gov (United States)

    de Jong, Maaike; Caro, Samuel P; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E

    2017-08-01

    Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits ( Cyanistes caeruleus) exposed to similar intensities of green, red, or white light at night. Birds advanced their onset of activity in the morning under all light colors but more under red and white light than under green light. Offset of activity was slightly delayed in all light colors. The total activity over a 24-h period did not change but birds moved a part of their daily activity into the night. Since the effect of red and white lights are comparable, we tested the influence of light intensity in a follow-up experiment, where we compared the activity of the birds under different intensities of green and white light only. While in the higher range of intensities, the effects of white and green light were comparable; at lower intensities, green light had a less disturbing effect as compared with white light on daily rhythms in blue tits. Our results show that the extent of this disturbance can be mitigated by modulating the spectral characteristics and intensity of outdoor lighting, which is now feasible through the use of LED lighting.

  1. Protective effect of blue-light shield eyewear for adults against light pollution from self-luminous devices used at night.

    Science.gov (United States)

    Ayaki, Masahiko; Hattori, Atsuhiko; Maruyama, Yusuke; Nakano, Masaki; Yoshimura, Michitaka; Kitazawa, Momoko; Negishi, Kazuno; Tsubota, Kazuo

    2016-01-01

    We investigated sleep quality and melatonin in 12 adults who wore blue-light shield or control eyewear 2 hours before sleep while using a self-luminous portable device, and assessed visual quality for the two eyewear types. Overnight melatonin secretion was significantly higher after using the blue-light shield (P light shield (P light shield as providing acceptable visual quality.

  2. A stable blue-light-derived signal modulates ultraviolet-light-induced activation of the chalcone-synthase gene in cultured parsley cells

    International Nuclear Information System (INIS)

    Ohl, S.; Hahlbrock, K.; Schäfer, E.

    1989-01-01

    Run-off transcription assays were used to demonstrate that both the ultraviolet (UV)-B and blue-light receptors control transcription rates for chalcone-synthase mRNA in the course of light-induced flavonoid synthesis in parsley (Petroselinum crispum Miller (A.W. Hill)) cell-suspension cultures. Blue and red light alone, presumably acting via a blue-light receptor and active phytochrome (far-red absorbing form) respectively, can induce accumulation of chalcone-synthase mRNA. The extent of the response is however considerably smaller than that obtained when these wavebands are applied in combination with UV light. A preirradiation with blue light strongly increases the response to a subsequent UV pulse and this modulating effect of blue light is stable for at least 20 h. The modulating effect is abolished by a UV induction but can be reestablished by a second irradiation with blue light. (author)

  3. Is the photoactive yellow protein a UV-B/blue light photoreceptor?

    NARCIS (Netherlands)

    Carroll, E. C.; Hospes, M.; Valladares, C.; Hellingwerf, K.J.; Larsen, D.S.

    2011-01-01

    UV light below 300 nm is shown to generate the first photocycle intermediate in the blue light photoreceptor Photoactive Yellow Protein. Fluorescence and ultrafast transient absorption measurements indicate two excitation pathways: UV-B absorption by the chromophore and Fluorescence Resonant Energy

  4. Improved power efficiency of blue fluorescent organic light-emitting diode with intermixed host structure

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Shouzhen; Zhang, Shiming; Zhang, Zhensong; Wu, Yukun; Wang, Peng; Guo, Runda; Chen, Yu; Qu, Dalong; Wu, Qingyang; Zhao, Yi, E-mail: yizhao@jlu.edu.cn; Liu, Shiyong

    2013-11-15

    High power efficiency (PE) p-bis(p-N,N-diphenyl-aminostyryl)benzene (DSA-ph) based fluorescent blue organic light-emitting diode (OLED) is demonstrated by utilizing intermixed host (IH) structure. The PE outperforms those devices based on single host (SH), mixed host (MH), and double emitting layers (DELs). By further optimizing the intermixed layer, peak PE of the IH device is increased up to 8.7 lm/W (1.7 times higher than conventional SH device), which is the highest value among the DSA-ph based blue device reported so far. -- Highlights: • DSA-ph based blue fluorescent OLEDs are fabricated. • The intermixed host structure is first introduced into the blue devices. • Blue device with the highest power efficiency based on DSA-ph is obtained.

  5. Cyclometalated Iridium(III) Carbene Phosphors for Highly Efficient Blue Organic Light-Emitting Diodes.

    Science.gov (United States)

    Chen, Zhao; Wang, Liqi; Su, Sikai; Zheng, Xingyu; Zhu, Nianyong; Ho, Cheuk-Lam; Chen, Shuming; Wong, Wai-Yeung

    2017-11-22

    Five deep blue carbene-based iridium(III) phosphors were synthesized and characterized. Interestingly, one of them can be fabricated into deep blue, sky blue and white organic light-emitting diodes (OLEDs) through changing the host materials and exciton blocking layers. These deep and sky blue devices exhibit Commission Internationale de l'Éclairage (CIE) coordinates of (0.145, 0.186) and (0.152, 0.277) with external quantum efficiency (EQE) of 15.2% and 9.6%, respectively. The EQE of the deep blue device can be further improved up to 19.0% by choosing a host with suitable energy level of its lowest unoccupied molecular orbital (LUMO).

  6. Blue light potentiates neurogenesis induced by retinoic acid-loaded responsive nanoparticles.

    Science.gov (United States)

    Santos, Tiago; Ferreira, Raquel; Quartin, Emanuel; Boto, Carlos; Saraiva, Cláudia; Bragança, José; Peça, João; Rodrigues, Cecília; Ferreira, Lino; Bernardino, Liliana

    2017-09-01

    Neurogenic niches constitute a powerful endogenous source of new neurons that can be used for brain repair strategies. Neuronal differentiation of these cells can be regulated by molecules such as retinoic acid (RA) or by mild levels of reactive oxygen species (ROS) that are also known to upregulate RA receptor alpha (RARα) levels. Data showed that neural stem cells from the subventricular zone (SVZ) exposed to blue light (405nm laser) transiently induced NADPH oxidase-dependent ROS, resulting in β-catenin activation and neuronal differentiation, and increased RARα levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis both in vitro and in vivo, while offering a temporal and spatial control of RA release. In conclusion, this combinatory treatment offers great advantages to potentiate neuronal differentiation, and provides an innovative and efficient application for brain regenerative therapies. Controlling the differentiation of stem cells would support the development of promising brain regenerative therapies. Blue light transiently increased reactive oxygen species, resulting in neuronal differentiation and increased retinoic acid receptor (RARα) levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis, while offering a temporal and spatial control of RA release. In this sense, our approach relying on the modulation of endogenous stem cells for the generation of new neurons may support the development of novel clinical therapies. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  7. Optimization of sensitometric properties of blue and green light sensitive dental radiographic films employing an automatic processor

    Directory of Open Access Journals (Sweden)

    Suchetha N Malleshi

    2011-01-01

    Full Text Available Background: Accurate film processing is of paramount importance in acquiring a good diagnostic radiograph. Radiographic films show variations in densities and contrast, with changes in processing conditions, and also film type, all of which are interdependent. Therefore, this research was conducted to recognize the effect of time and temperature variations of automatic processor on the sensitometric properties of blue and green light sensitive screen films. The study also aimed to note the effect on sensitometric properties when mismatch occurred when using between the screen and film belonging to different manufacturers. Materials and Methods: Sixty green light sensitive and 60 blue light sensitive spectrally matched screen film combinations were used in the study. However, the films and the intensifying screens employed belonged to different manufacturers. These films were exposed to five different exposure times and subsequently processed in an automatic processor, using two different protocols. Initially, at constant processing time of 2.5 min, five different processing temperatures were employed. Later, maintaining constant processing temperature of 35°C and five different processing times were engaged. Density, contrast and speed were calculated, using H and D curve. Results: Results revealed increasing density, contrast and speed values with increasing processing times and temperatures of both green and blue sensitive films. Conclusion: This investigation clearly establishes the possibility of obtaining optimal sensitometric properties, despite using intensifying screens and films of different manufacturers, if spectral match is ensured.

  8. The treatment of crigler-najjar syndrome by blue light as explained by resonant recognition model

    Directory of Open Access Journals (Sweden)

    Cosic Irena

    2016-12-01

    However, the blue light treatment is less effective with ageing, due to decrease of the blue lightpenetration through skin. Thus, there is a need for alternative treatments. Here, we propose to design de-novopeptide, using this specific RRM frequency. Such peptide, according to RRM, is proposed to have the samebiological function as UDP glucuronosyltransferase 1-A1 and thus can be used for alternative treatment of Crigler-Najjar syndrome.

  9. Blue Organic Light-Emitting Diodes Based on Triphenylene Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seul Ong; Jang, Heung Soo; Yoon, Seung Soo [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Seok Jae; Kim, Young Kwan [Hongik Univ., Seoul (Korea, Republic of)

    2013-08-15

    A series of blue fluorescent emitters based on triphenylene derivatives were synthesized via the Diels -Alder reaction in moderate yields. The electronic absorption and emission characteristics of the new functional materials were affected by the nature of the substituent on the triphenylene nucleus. Multilayered OLEDs were fabricated with a device structure of: ITO/NPB (50 nm)/EML (30 nm)/Bphen (30 nm)/Liq (2.0 nm)/Al (100 nm). All devices showed efficient blue emissions. Among those, a device using 1 gives the best performances with a high brightness (978 cd m{sup -2} at 8.0 V) and high efficiencies (a luminous efficiency of 0.80 cd/A, a power efficiency of 0.34 lm/W and an external quantum efficiency of 0.73% at 20 mA/cm{sup 2}). The peak wavelength of the electroluminescence was 455 nm with CIE{sub x,y} coordinates of (0.17, 0.14) at 8.0 V.

  10. Emission of blue light from hydrogenated amorphous silicon carbide

    Science.gov (United States)

    Nevin, W. A.; Yamagishi, H.; Yamaguchi, M.; Tawada, Y.

    1994-04-01

    THE development of new electroluminescent materials is of current technological interest for use in flat-screen full-colour displays1. For such applications, amorphous inorganic semiconductors appear particularly promising, in view of the ease with which uniform films with good mechanical and electronic properties can be deposited over large areas2. Luminescence has been reported1 in the red-green part of the spectrum from amorphous silicon carbide prepared from gas-phase mixtures of silane and a carbon-containing species (usually methane or ethylene). But it is not possible to achieve blue luminescence by this approach. Here we show that the use of an aromatic species-xylene-as the source of carbon during deposition results in a form of amorphous silicon carbide that exhibits strong blue luminescence. The underlying structure of this material seems to be an unusual combination of an inorganic silicon carbide lattice with a substantial 'organic' π-conjugated carbon system, the latter dominating the emission properties. Moreover, the material can be readily doped with an electron acceptor in a manner similar to organic semiconductors3, and might therefore find applications as a conductivity- or colour-based chemical sensor.

  11. Phosphorous Diffuser Diverged Blue Laser Diode for Indoor Lighting and Communication

    KAUST Repository

    Chi, Yu-Chieh

    2015-12-21

    An advanced light-fidelity (Li-Fi) system based on the blue Gallium nitride (GaN) laser diode (LD) with a compact white-light phosphorous diffuser is demonstrated for fusing the indoor white-lighting and visible light communication (VLC). The phosphorous diffuser adhered blue GaN LD broadens luminescent spectrum and diverges beam spot to provide ample functionality including the completeness of Li-Fi feature and the quality of white-lighting. The phosphorous diffuser diverged white-light spot covers a radiant angle up to 120o with CIE coordinates of (0.34, 0.37). On the other hand, the degradation on throughput frequency response of the blue LD is mainly attributed to the self-feedback caused by the reflection from the phosphor-air interface. It represents the current state-of-the-art performance on carrying 5.2-Gbit/s orthogonal frequency-division multiplexed 16-quadrature-amplitude modulation (16-QAM OFDM) data with a bit error rate (BER) of 3.1 × 10−3 over a 60-cm free-space link. This work aims to explore the plausibility of the phosphorous diffuser diverged blue GaN LD for future hybrid white-lighting and VLC systems.

  12. Inhibitory effect of blue light emitting diode on migration and invasion of cancer cells.

    Science.gov (United States)

    Oh, Phil-Sun; Kim, Hyun-Soo; Kim, Eun-Mi; Hwang, Hyosook; Ryu, Hyang Hwa; Lim, SeokTae; Sohn, Myung-Hee; Jeong, Hwan-Jeong

    2017-12-01

    The aim of this study was to determine the effects and molecular mechanism of blue light emitting diode (LED) in tumor cells. A migration and invasion assay for the metastatic behavior of mouse colon cancer CT-26 and human fibrosarcoma HT-1080 cells was performed. Cancer cell migration-related proteins were identified by obtaining a 2-dimensional gel electrophoresis (2-DE) in total cellular protein profile of blue LED-irradiated cancer cells, followed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis of proteins. Protein levels were examined by immunoblotting. Irradiation with blue LED inhibited CT-26 and HT-1080 cell migration and invasion. The anti-metastatic effects of blue LED irradiation were associated with inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 expression. P38 MAPK phosphorylation was increased in blue LED-irradiated CT-26 and HT-1080 cells, but was inhibited after pretreatment with SB203580, a specific inhibitor of p38 MAPK. Inhibition of p38 MAPK phosphorylation by SB203580 treatment increased number of migratory cancer cells in CT-26 and HT-1080 cells, indicating that blue LED irradiation inhibited cancer cell migration via phosphorylation of p38 MAPK. Additionally blue LED irradiation of mice injected with CT-26 cells expressing luciferase decreased early stage lung metastasis compared to untreated control mice. These results indicate that blue LED irradiation inhibits cancer cell migration and invasion in vitro and in vivo. © 2017 Wiley Periodicals, Inc.

  13. Conductive stability of graphene on PET and glass substrates under blue light irradiation

    Science.gov (United States)

    Cao, Xueying; Liu, Xianming; Li, Xiangdi; Lei, Xiaohua; Chen, Weimin

    2018-01-01

    Electrical properties of graphene transparent conductive film under visible light irradiation are investigated. The CVD-grown graphene on Polyethylene Terephthalate (PET) and glass substrates for flexible and rigid touch screen display application are chosen for research. The resistances of graphene with and without gold trichloride (AuCl3) doping are measured in vacuum and atmosphere environment under blue light irradiation. Results show that the conductivities of all samples change slowly under light irradiation. The change rate and degree are related to the substrate material, doping, environment and lighting power. Graphene on flexible PET substrate is more stable than that on rigid glass substrate. Doping can improve the electrical conductivity but induce instability under light irradiation. Finally, the main reason resulting in the graphene resistance slowly increasing under blue light irradiation is analyzed.

  14. Output blue light evaluation for phosphor based smart white LED wafer level packages.

    Science.gov (United States)

    Kolahdouz, Zahra; Rostamian, Ali; Kolahdouz, Mohammadreza; Ma, Teng; van Zeijl, Henk; Zhang, Kouchi

    2016-02-22

    This study presents a blue light detector for evaluating the output light of phosphor based white LED package. It is composed of a silicon stripe-shaped photodiode designed and implemented in a 2 μm BiCMOS process which can be used for wafer level integration of different passive and active devices all in just 5 lithography steps. The final device shows a high selectivity to blue light. The maximum responsivity at 480 nm is matched with the target blue LED illumination. The designed structure have better responsivity compared to simple photodiode structure due to reducing the effect of dead layer formation close to the surface because of implantation. It has also a two-fold increase in the responsivity and quantum efficiency compared to previously similar published sensors.

  15. Background story of the invention of efficient blue InGaN light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Shuji [University of California, Santa Barbara, CA (United States)

    2015-06-15

    Shuji Nakamura discovered p-type doping in Gallium Nitride (GaN) and developed blue, green, and white InGaN based light emitting diodes (LEDs) and blue laser diodes (LDs). His inventions made possible energy efficient, solid-state lighting systems and enabled the next generation of optical storage. Together with Isamu Akasaki and Hiroshi Amano, he is one of the three recipients of the 2014 Nobel Prize in Physics. In his Nobel lecture, Shuji Nakamura gives an overview of this research and the story of his inventions. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. The plasma membrane-associated NADH oxidase (ECTO-NOX) of mouse skin responds to blue light

    Science.gov (United States)

    Morre, D. James; Morre, Dorothy M.

    2003-01-01

    NADH oxidases of the external plasma membrane surface (ECTO-NOX proteins) are characterized by oscillations in activity with a regular period length of 24 min. Explants of mouse skin exhibit the oscillatory activity as estimated from the decrease in A(340) suggesting that individual ECTO-NOX molecules must somehow be induced to function synchronously. Transfer of explants of mouse skin from darkness to blue light (495 nm, 2 min, 50 micromol m(-1) s(-1)) resulted in initiation of a new activity maximum (entrainment) with a midpoint 36 min after light exposure followed by maxima every 24 min thereafter. Addition of melatonin resulted in a new maximum 24 min after melatonin addition. The findings suggest that the ECTO-NOX proteins play a central role in the entrainment of the biological clock both by light and by melatonin.

  17. Antimicrobial blue light inactivation of biofilms formed by clinical isolates of multidrug-resistant microorganisms

    Science.gov (United States)

    Ferrer-Espada, Raquel; Fang, Yanyan; Dai, Tianhong

    2018-02-01

    Antibiotic resistance is one of the most serious threats to public health. It is estimated that at least 23,000 people die each year in the USA as a direct result of antibiotic-resistant infections. In addition, many antibiotic-resistant microorganisms develop biofilms, surface-associated microbial communities that are extremely resistant to antibiotics and the immune system. A light-based approach, antimicrobial blue light (aBL), has attracted increasing attention due to its intrinsic antimicrobial effect without the involvement of exogenous photosensitizers. In this study, we investigated the effectiveness of this non-antibiotic approach against biofilms formed by multidrug-resistant (MDR) microorganisms. MDR Acinetobacter baumannii, Escherichia coli, Candida albicans, and Pseudomonas aeruginosa biofilms were grown either in 96-well microtiter plates for 24 h or in a CDC biofilm reactor for 48 h, and then exposed to aBL at 405 nm emitted from a light-emitting diode (LED). We demonstrated that, for the biofilms grown in the CDC biofilm reactor, approximately 1.88 log10 CFU reduction was achieved in A. baumannii, 2.78 log10 CFU in E. coli and 3.18 log10 CFU in P. aeruginosa after 162 J/cm2 , 576 J/cm2 and 500 J/cm2 aBL were delivered, respectively. For the biofilms formed in the 96-well microtiter plates, 5.67 and 2.46 log10 CFU reduction was observed in P. aeruginosa and C. albicans polymicrobial biofilm after an exposure of 216 J/cm2 . In conclusion, aBL is potentially an alternative non-antibiotic approach against MDR biofilm-related infections. Future studies are warranted to investigate other important MDR microorganisms, the mechanism of action of aBL, and aBL efficacy in vivo.

  18. Effect of Violet-Blue Light on Streptococcus mutans-Induced Enamel Demineralization

    Directory of Open Access Journals (Sweden)

    Grace Gomez Felix Gomez

    2018-03-01

    Full Text Available Background: This in vitro study determined the effectiveness of violet-blue light (405 nm on inhibiting Streptococcus mutans-induced enamel demineralization. Materials and Methods: S. mutans UA159 biofilm was grown on human enamel specimens for 13 h in 5% CO2 at 37 °C with/without 1% sucrose. Wet biofilm was treated twice daily with violet-blue light for five minutes over five days. A six-hour reincubation was included daily between treatments excluding the final day. Biofilms were harvested and colony forming units (CFU were quantitated. Lesion depth (L and mineral loss (∆Z were quantified using transverse microradiography (TMR. Quantitative light-induced fluorescence Biluminator (QLF-D was used to determine mean fluorescence loss. Data were analyzed using one-way analysis of variance (ANOVA to compare differences in means. Results: The results demonstrated a significant reduction in CFUs between treated and non-treated groups grown with/without 1% sucrose. ∆Z was significantly reduced for specimens exposed to biofilms grown without sucrose with violet-blue light. There was only a trend on reduction of ∆Z with sucrose and with L on both groups. There were no differences in fluorescence-derived parameters between the groups. Conclusions: Within the limitations of the study, the results indicate that violet-blue light can serve as an adjunct prophylactic treatment for reducing S. mutans biofilm formation and enamel mineral loss.

  19. Blue light enhances the antimicrobial activity of honey against Pseudomonas aeruginosa

    Science.gov (United States)

    Orlandi, Viviana Teresa; Bolognese, Fabrizio; Barbieri, Paola

    2018-02-01

    Pseudomonas aeruginosa may be isolated from skin wounds of burn patients, bedsore and diabetic ulcers. The healing of wounds is often impaired by the intrinsic antibiotic resistance, the tolerance to many antimicrobials and the ability to form biofilm of this opportunistic pathogen. Finding new topical treatments to combine with antibiotics is thus essential. Among natural products, the antimicrobial properties of honeys have been known for millennia. In this study honey and visible light have been combined to control the growth of P. aeruginosa PAO1. The irradiation by a broad spectrum light source of bacteria inoculated onto 2 % w/v fir and forest honeydew (HD) honeys caused a killing effect that the honeys alone or the light alone did not show. This antimicrobial activity was light energy-dose and honey-concentration dependent. Among the tested honeys, the fir and forest HD honeys were the most efficient ones. In particular, the irradiation by blue LED (λmax = 466 nm) yielded good rates of killing, that were significantly higher in comparison to irradiation alone and honey alone. Interestingly, a similar effect was obtained by plating bacteria on blue LED pre-irradiated HD honeys. The combined use of honey and blue light was also successful in inhibiting the biofilm formation of P. aeruginosa. The blue LED irradiation of PAO1 administered with 10 % w/v forest HD honey significantly enhanced the inhibition of biofilm formation in comparison to dark incubated honey.

  20. The Histopathological Investigation of Red and Blue Light Emitting Diode on Treating Skin Wounds in Japanese Big-Ear White Rabbit.

    Directory of Open Access Journals (Sweden)

    Yanhong Li

    Full Text Available The biological effects of different wavelengths of light emitting diode (LED light tend to vary from each other. Research into use of photobiomodulation for treatment of skin wounds and the underlying mechanisms has been largely lacking. We explored the histopathological basis of the therapeutic effect of photobiomodulation and the relation between duration of exposure and photobiomodulation effect of different wavelengths of LED in a Japanese big-ear white rabbit skin-wound model. Skin wound model was established in 16 rabbits (three wounds per rabbit: one served as control, the other two wounds were irradiated by red and blue LED lights, respectively. Rabbits were then divided into 2 equal groups based on the duration of exposure to LED lights (15 and 30 min/exposure. The number of wounds that showed healing and the percentage of healed wound area were recorded. Histopathological examination and skin expression levels of fibroblast growth factor (FGF, epidermal growth factor (EGF, endothelial marker (CD31, proliferating cell nuclear antigen (Ki67 and macrophagocyte (CD68 infiltration, and the proliferation of skin collagen fibers was assessed. On days 16 and 17 of irradiation, the healing rates in red (15 min and 30 min and blue (15 min and 30 min groups were 50%, 37.5%, 25% and 37.5%, respectively, while the healing rate in the control group was 12.5%. The percentage healed area in the red light groups was significantly higher than those in other groups. Collagen fiber and skin thickness were significantly increased in both red light groups; expression of EGF, FGF, CD31 and Ki67 in the red light groups was significantly higher than those in other groups; the expression of FGF in red (30 min group was not significantly different from that in the blue light and control groups. The effect of blue light on wound healing was poorer than that of red light. Red light appeared to hasten wound healing by promoting fibrous tissue, epidermal and

  1. Action of UV-A and blue light on enzymes activity and accumulation of lipid peroxidation products in attached and detached frog retinas

    Science.gov (United States)

    Lapina, Victoria A.; Doutsov, Alexander E.

    1994-07-01

    The effect of the UV-A and blue light on the accumulation of lipid peroxidation products and activities of succinate dehydrogenase and superoxide dismutase in the retina was examined in eye cup model of dark and light adapted frogs R. temporaria. Retinas were exposed to UV-A radiation (8 mW/cm2) and blue light (10 to 150 mW/cm2) for periods from 5 min to 1 hr. We have measured TBA-active products both in the retina homogenates and in the reaction media. Enzyme activities was measured in the retina homogenates only. The measurements revealed a significant increase in the endogenous and exogenous forms of lipid peroxidation products in the retina of dark adapted frog (1.6+/- 0.4; 1.4+/- 0.3 nmole TBA-active products per mg protein, respectively) compared to light adapted (0.85+/- 0.16; 0.32+/- 0.06 nmole TBA-active products per mg protein, respectively). In the same conditions succinate dehydrogenase activity was decline more than 50% but superoxide dismutase activity didn't decrease. Disorganized inner and outer segments were observed after 40 min exposures. No light microscopic changes were detected after 5 min exposures. Light damage was significantly higher in the retina of dark adapted frog. The results indicate that the retina from eye cup of dark adapted frog is more susceptible to UV-A and blue light damages.

  2. Combined Effects of Blue and Ultraviolet Lights on the Accumulation of Flavonoids in Tartary Buckwheat Sprouts

    Directory of Open Access Journals (Sweden)

    Ji Hongbin

    2016-06-01

    Full Text Available The effects of blue and UV-A (365 nm/UV-C (254 nm or their combinations on the levels of total flavonoids, rutin, quercetin, phenylalanine ammonialyase (PAL, chalcone isomerase (CHI, rutin degrading enzymes (RDEs and 1,1-diphenyl-2-picrylhydrazyl (DPPH radical scavenging activity in tartary buckwheat sprouts were investigated in this study. The total flavonoids content in the tartary buckwheat sprouts irradiated with blue light followed by UV-C (BL+UV-C raised by 10%, compared with the opposite combination sequence (UV-C+BL. However, blue light did not show the same results when combined with UV-A, and their combinations on the accumulation of total flavonoids were still lower than that of UV-A/UV-C. Key enzymes (PAL, CHI and RDEs revealed a significant correlation with total flavonoids in tartary buckwheat sprouts.

  3. Highly efficient deep-blue organic light emitting diode with a carbazole based fluorescent emitter

    Science.gov (United States)

    Sahoo, Snehasis; Dubey, Deepak Kumar; Singh, Meenu; Joseph, Vellaichamy; Thomas, K. R. Justin; Jou, Jwo-Huei

    2018-04-01

    High efficiency deep-blue emission is essential to realize energy-saving, high-quality display and lighting applications. We demonstrate here a deep-blue organic light emitting diode using a novel carbazole based fluorescent emitter 7-[4-(diphenylamino)phenyl]-9-(2-ethylhexyl)-9H-carbazole-2-carbonitrile (JV234). The solution processed resultant device shows a maximum luminance above 1,750 cd m-2 and CIE coordinates (0.15,0.06) with a 1.3 lm W-1 power efficiency, 2.0 cd A-1 current efficiency, and 4.1% external quantum efficiency at 100 cd m-2. The resulting deep-blue emission enables a greater than 100% color saturation. The high efficiency may be attributed to the effective host-to-guest energy transfer, suitable device architecture facilitating balanced carrier injection and low doping concentration preventing efficiency roll-off caused by concentration quenching.

  4. Supplemental Blue LED Lighting Array to Improve the Signal Quality in Hyperspectral Imaging of Plants

    Directory of Open Access Journals (Sweden)

    Anne-Katrin Mahlein

    2015-06-01

    Full Text Available Hyperspectral imaging systems used in plant science or agriculture often have suboptimal signal-to-noise ratio in the blue region (400–500 nm of the electromagnetic spectrum. Typically there are two principal reasons for this effect, the low sensitivity of the imaging sensor and the low amount of light available from the illuminating source. In plant science, the blue region contains relevant information about the physiology and the health status of a plant. We report on the improvement in sensitivity of a hyperspectral imaging system in the blue region of the spectrum by using supplemental illumination provided by an array of high brightness light emitting diodes (LEDs with an emission peak at 470 nm.

  5. Blue light hazards for ocular lesions; Risques oculaires du rayonnement bleu

    Energy Technology Data Exchange (ETDEWEB)

    Cesarini, J.P. [INSERM, Fondation Ophtalmologique A. de Rothschild, 75 - Paris (France); CES, Agents physique, AFSSET (France)

    2009-10-15

    The blue light range (400-500 nm) of visible radiation stimulates specifically cones and rods of the retina. The carried energy by these wavelengths is absorbed and transferred to specific pigments. Their energy is sufficient to produce free radicals and singlet form of oxygen. Intense sources, rich in blue light radiation, may induce, in the retina, photo-toxic lesions either limited or short-lived or photothermal lesions more or less definitive. Repeated photo-toxic lesions should be the root for the age-related maculo-pathy (A.R.M.) also called late macular degeneration (A.M.D.). As a consequence, the attention should be drawn on the potential risk linked to modern lighting as 'daylight' lamp, compact fluorescent lamps, energy saving (C.F.L.) and light-emitting diodes (L.E.D.) for which a specific vigilance should be enforced. (author)

  6. UV-A/blue-light responses in algae

    Energy Technology Data Exchange (ETDEWEB)

    Senger, H.; Hermsmeier, D. [Philipps-Universitaet Marburg (Germany)

    1994-12-31

    All life on earth depends on light. A variety of photoreceptors capture the light for a wide range of reactions. Photosynthetic organisms absorb the light necessary for energy transformation and charge separation facilitating photosynthesis. In addition to the bulk pigments there are a great diversity of photoreceptors present in minute concentrations that control development, metabolism and orientation of plants and microorganisms. Based on its spectral absorbance, the well-studied phytochrome system acts in the RL region as well as in the UV-A/BL region where the above mentioned reactions are mediated by a variety of photoreceptors whose natures are largely unknown. Phyllogenetically the UV-A/BL photoreceptors seem to be more ancient pigments that eventually were replaced by the phytochrome system. However, there are many reports that suggest a coaction between the UV-A/BL receptors and the phytochrome system. In several cases the UV-A/BL activation is the prerequisite for the phytochrome reaction. Historically it was the German botanist Julius Sachs who first discovered in 1864 that phototropism in plants was due to BL reactions. It took over 70 years until Bunning (1937) and Galston and Baker (1949) rediscovered the BL response. Since then, an ever-increasing attention has been paid to this effect. Two international conferences in 1979 and 1983 have been entirely dedicated to the BL phenomenon. In this contribution, the general aspect of UV-A/BL responses and especially the responsiveness of algae will be covered. There are numerous review articles covering the various aspects of UV-A/BL action and the photoreceptors involved.

  7. Phototropin 2 is involved in blue light-induced anthocyanin accumulation in Fragaria x ananassa fruits.

    Science.gov (United States)

    Kadomura-Ishikawa, Yasuko; Miyawaki, Katsuyuki; Noji, Sumihare; Takahashi, Akira

    2013-11-01

    Anthocyanins are widespread, essential secondary metabolites in higher plants during color development in certain flowers and fruits. In strawberries, anthocyanins are also key contributors to fruit antioxidant capacity and nutritional value. However, the effects of different light qualities on anthocyanin accumulation in strawberry (Fragaria x ananassa, cv. Sachinoka) fruits remain elusive. In the present study, we showed the most efficient increase in anthocyanin content occurred by blue light irradiation. Light sensing at the molecular level was investigated by isolation of two phototropin (FaPHOT1 and FaPHOT2), two cryptochrome (FaCRY1 and FaCRY2), and two phytochrome (FaPHYA and FaPHYB) homologs. Expression analysis revealed only FaPHOT2 transcripts markedly increased depending on fruit developmental stage, and a corresponding increase in anthocyanin content was detected. FaPHOT2 knockdown resulted in decreased anthocyanin content; however, overexpression increased anthocyanin content. These findings suggested blue light induced anthocyanin accumulation, and FaPHOT2 may play a role in sensing blue light, and mediating anthocyanin biosynthesis in strawberry fruits. This is the first report to find a relationship between visible light sensing, and color development in strawberry fruits.

  8. Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer

    Directory of Open Access Journals (Sweden)

    Kristina eHerbst

    2011-02-01

    Full Text Available In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at 2 selected wavelengths (660 nm and 470 nm, intensity 300 cd/m2 presented continuously for 20 seconds. Pupil responses were recorded in real time before, during and after light exposure. Maximal contraction amplitude and sustained contraction amplitude were calculated. In addition, we quantified the summed pupil response during continuous light stimulation as the total area between a reference line representing baseline pupil size and the line representing actual pupil size over 20 seconds (area under the curve. There was no significant difference in the repeated measure compared to the first test for any of the pupil response parameters. In conclusion, we have developed a novel prototype of color pupillometer which demonstrates good repeatability in evoking and recording the pupillary response to a bright blue and red light stimulus.

  9. 77 FR 76170 - Presumption of Exposure to Herbicides for Blue Water Navy Vietnam Veterans Not Supported

    Science.gov (United States)

    2012-12-26

    ... during the Vietnam War. After careful review of the IOM report, the Secretary determines that the... served in deep-water naval vessels off the coast of Vietnam during the Vietnam War are referred to as... DEPARTMENT OF VETERANS AFFAIRS Presumption of Exposure to Herbicides for Blue Water Navy Vietnam...

  10. Blue light-irradiated human keloid fibroblasts: an in vitro study

    Science.gov (United States)

    Magni, Giada; Rossi, Francesca; Tatini, Francesca; Pini, Roberto; Coppi, Elisabetta; Cherchi, Federica; Fusco, Irene; Pugliese, Anna Maria; Pedata, Felicita; Fraccalvieri, Marco; Gasperini, Stefano; Pavone, Francesco S.; Tripodi, Cristina; Alfieri, Domenico; Targetti, Lorenzo

    2018-02-01

    Blue LED light irradiation is currently under investigation because of its effect in wound healing improvement. In this context, several mechanisms of action are likely to occur at the same time, consistently with the presence of different light absorbers within the skin. In our previous studies we observed the wound healing in superficial abrasions in an in vivo murine model. The results evidenced that both inflammatory infiltrate and myofibroblasts activity increase after irradiation. In this study we focused on evaluating the consequences of light absorption in fibroblasts from human cells culture: they play a key role in wound healing, both in physiological conditions and in pathological ones, such as keloid scarring. In particular we used keloids fibroblasts as a new target in order to investigate a possible metabolic or cellular mechanism correlation. Human keloid tissues were excised during standard surgery and immediately underwent primary cell culture extraction. Fibroblasts were allowed to grow in the appropriate conditions and then exposed to blue light. A metabolic colorimetric test (WST-8) was then performed. The tests evidenced an effect in mitochondrial activity, which could be modulated by the duration of the treatment. Electrophysiology pointed out a different behavior of irradiated fibroblasts. In conclusion, the Blue LED light affects the metabolic activity of fibroblasts and thus the cellular proliferation rate. No specific effect was found on keloid fibroblasts, thus indicating a very basic intracellular component, such as cytochromes, being the target of the treatment.

  11. Analysis of Pigeon (Columba) Ovary Transcriptomes to Identify Genes Involved in Blue Light Regulation

    Science.gov (United States)

    Wang, Ying; Ding, Jia-tong; Yang, Hai-ming; Yan, Zheng-jie; Cao, Wei; Li, Yang-bai

    2015-01-01

    Monochromatic light is widely applied to promote poultry reproductive performance, yet little is currently known regarding the mechanism by which light wavelengths affect pigeon reproduction. Recently, high-throughput sequencing technologies have been used to provide genomic information for solving this problem. In this study, we employed Illumina Hiseq 2000 to identify differentially expressed genes in ovary tissue from pigeons under blue and white light conditions and de novo transcriptome assembly to construct a comprehensive sequence database containing information on the mechanisms of follicle development. A total of 157,774 unigenes (mean length: 790 bp) were obtained by the Trinity program, and 35.83% of these unigenes were matched to genes in a non-redundant protein database. Gene description, gene ontology, and the clustering of orthologous group terms were performed to annotate the transcriptome assembly. Differentially expressed genes between blue and white light conditions included those related to oocyte maturation, hormone biosynthesis, and circadian rhythm. Furthermore, 17,574 SSRs and 533,887 potential SNPs were identified in this transcriptome assembly. This work is the first transcriptome analysis of the Columba ovary using Illumina technology, and the resulting transcriptome and differentially expressed gene data can facilitate further investigations into the molecular mechanism of the effect of blue light on follicle development and reproduction in pigeons and other bird species. PMID:26599806

  12. Analysis of Pigeon (Columba Ovary Transcriptomes to Identify Genes Involved in Blue Light Regulation.

    Directory of Open Access Journals (Sweden)

    Ying Wang

    Full Text Available Monochromatic light is widely applied to promote poultry reproductive performance, yet little is currently known regarding the mechanism by which light wavelengths affect pigeon reproduction. Recently, high-throughput sequencing technologies have been used to provide genomic information for solving this problem. In this study, we employed Illumina Hiseq 2000 to identify differentially expressed genes in ovary tissue from pigeons under blue and white light conditions and de novo transcriptome assembly to construct a comprehensive sequence database containing information on the mechanisms of follicle development. A total of 157,774 unigenes (mean length: 790 bp were obtained by the Trinity program, and 35.83% of these unigenes were matched to genes in a non-redundant protein database. Gene description, gene ontology, and the clustering of orthologous group terms were performed to annotate the transcriptome assembly. Differentially expressed genes between blue and white light conditions included those related to oocyte maturation, hormone biosynthesis, and circadian rhythm. Furthermore, 17,574 SSRs and 533,887 potential SNPs were identified in this transcriptome assembly. This work is the first transcriptome analysis of the Columba ovary using Illumina technology, and the resulting transcriptome and differentially expressed gene data can facilitate further investigations into the molecular mechanism of the effect of blue light on follicle development and reproduction in pigeons and other bird species.

  13. Combined effects of blue light and supplemental far-red light and effects of increasing red light with constant far-red light on growth of kidney bean [Phaseolus vulgaris] under mixtures of narrow-band light sources

    International Nuclear Information System (INIS)

    Hanyu, H.; Shoji, K.

    2000-01-01

    Increasing blue light and decreasing R: FR with supplementary far-red light affect morphogenesis, dry matter production and dry matter partitioning to leaves, stems and roots. In this study, the combined effects of the two spectral treatments were examined in kidney bean (Phaseolus vulgaris L.) grown under the mixture of four different narrow-band light sources. In addition, because the leaf and stem growth are accelerated by increasing red light (600-700 nm) in proportion to far-red light (700-800 nm) while keeping R : FR constant, this study was conducted to determine whether red light or far-red light causes the acceleration of growth. Increasing blue light (400-500 nm) and decreasing R : FR only interacted on stem extension. The results illustrated with figures suggest that blue light amplifies or attenuates the acceleration of stem extension caused by decreasing R : FR. On the other hand, increasing red light with constant far-red light had no influence on leaf expansion or stem extension while R : FR increased. Because the acceleration of leaf and stem growth is caused by increasing either far-red light or both red and far-red light in our environmental conditions, the stimulative effects on leaves and stems seem to require increases in far-red light rather than red light

  14. Deep-blue supercontinuum light sources based on tapered photonic crystal bres

    DEFF Research Database (Denmark)

    Sørensen, Simon Toft

    applications in areas such as spectroscopy and microscopy. In this work, we exploit the tremendous design freedom in air hole structured photonic crystal fibres to shape the supercontinuum spectrum. Specifically, the supercontinuum dynamics can be controlled by clever engineering of fibres with longitudinally...... varying air hole structures. Here we demonstrate supercontinuum generation into the commercially attractive deep-blue spectral region below 400 nm from an Yb laser in such fibres. In particular, we introduce the concept of a group acceleration mismatch that allows us to enhance the amount of light...... in the deep-blue by optimising the fibre structure. To this end, we fabricate the first single-mode high air-fill fraction photonic crystal fibre for blue-extended supercontinuum sources. The mechanisms of supercontinuum broadening are highly sensitive to noise, and the inherent shot-to-shot variations...

  15. An Exciplex Host for Deep-Blue Phosphorescent Organic Light-Emitting Diodes.

    Science.gov (United States)

    Lim, Hyoungcheol; Shin, Hyun; Kim, Kwon-Hyeon; Yoo, Seung-Jun; Huh, Jin-Suk; Kim, Jang-Joo

    2017-11-01

    The use of exciplex hosts is attractive for high-performance phosphorescent organic light-emitting diodes (PhOLEDs) and thermally activated delayed fluorescence OLEDs, which have high external quantum efficiency, low driving voltage, and low efficiency roll-off. However, exciplex hosts for deep-blue OLEDs have not yet been reported because of the difficulties in identifying suitable molecules. Here, we report a deep-blue-emitting exciplex system with an exciplex energy of 3.0 eV. It is composed of a carbazole-based hole-transporting material (mCP) and a phosphine-oxide-based electron-transporting material (BM-A10). The blue PhOLEDs exhibited maximum external quantum efficiency of 24% with CIE coordinates of (0.15, 0.21) and longer lifetime than the single host devices.

  16. Highly efficient blue and warm white organic light-emitting diodes with a simplified structure

    International Nuclear Information System (INIS)

    Li, Xiang-Long; Chen, Dongcheng; Cai, Xinyi; Liu, Ming; Cao, Yong; Su, Shi-Jian; Ouyang, Xinhua; Ge, Ziyi

    2016-01-01

    Two blue fluorescent emitters were utilized to construct simplified organic light-emitting diodes (OLEDs) and the remarkable difference in device performance was carefully illustrated. A maximum current efficiency of 4.84 cd A"−"1 (corresponding to a quantum efficiency of 4.29%) with a Commission Internationale de l’Eclairage (CIE) coordinate of (0.144, 0.127) was achieved by using N,N-diphenyl-4″-(1-phenyl-1H-benzo[d]imidazol-2-yl)-[1, 1′:4′, 1″-terphenyl]-4-amine (BBPI) as a non-doped emission layer of the simplified blue OLEDs without carrier-transport layers. In addition, simplified fluorescent/phosphorescent (F/P) hybrid warm white OLEDs without carrier-transport layers were fabricated by utilizing BBPI as (1) the blue emitter and (2) the host of a complementary yellow phosphorescent emitter (PO-01). A maximum current efficiency of 36.8 cd A"−"1 and a maximum power efficiency of 38.6 lm W"−"1 were achieved as a result of efficient energy transfer from the host to the guest and good triplet exciton confinement on the phosphorescent molecules. The blue and white OLEDs are among the most efficient simplified fluorescent blue and F/P hybrid white devices, and their performance is even comparable to that of most previously reported complicated multi-layer devices with carrier-transport layers. (paper)

  17. Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes

    Science.gov (United States)

    Suzuri, Yoshiyuki; Oshiyama, Tomohiro; Ito, Hiroto; Hiyama, Kunihisa; Kita, Hiroshi

    2014-10-01

    Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration.

  18. Transcriptome Analysis Reveals that Red and Blue Light Regulate Growth and Phytohormone Metabolism in Norway Spruce [Picea abies (L. Karst].

    Directory of Open Access Journals (Sweden)

    Fangqun OuYang

    Full Text Available The mechanisms by which different light spectra regulate plant shoot elongation vary, and phytohormones respond differently to such spectrum-associated regulatory effects. Light supplementation can effectively control seedling growth in Norway spruce. However, knowledge of the effective spectrum for promoting growth and phytohormone metabolism in this species is lacking. In this study, 3-year-old Norway spruce clones were illuminated for 12 h after sunset under blue or red light-emitting diode (LED light for 90 d, and stem increments and other growth traits were determined. Endogenous hormone levels and transcriptome differences in the current needles were assessed to identify genes related to the red and blue light regulatory responses. The results showed that the stem increment and gibberellin (GA levels of the seedlings illuminated by red light were 8.6% and 29.0% higher, respectively, than those of the seedlings illuminated by blue light. The indoleacetic acid (IAA level of the seedlings illuminated by red light was 54.6% lower than that of the seedlings illuminated by blue light, and there were no significant differences in abscisic acid (ABA or zeatin riboside [ZR] between the two groups of seedlings. The transcriptome results revealed 58,736,166 and 60,555,192 clean reads for the blue-light- and red-light-illuminated samples, respectively. Illumina sequencing revealed 21,923 unigenes, and 2744 (approximately 93.8% out of 2926 differentially expressed genes (DEGs were found to be upregulated under blue light. The main KEGG classifications of the DEGs were metabolic pathway (29%, biosynthesis of secondary metabolites (20.49% and hormone signal transduction (8.39%. With regard to hormone signal transduction, AUXIN-RESISTANT1 (AUX1, AUX/IAA genes, auxin-inducible genes, and early auxin-responsive genes [(auxin response factor (ARF and small auxin-up RNA (SAUR] were all upregulated under blue light compared with red light, which might have

  19. Blue light filtered white light induces depression-like responses and temporary spatial learning deficits in rats.

    Science.gov (United States)

    Meng, Qinghe; Lian, Yuzheng; Jiang, Jianjun; Wang, Wei; Hou, Xiaohong; Pan, Yao; Chu, Hongqian; Shang, Lanqin; Wei, Xuetao; Hao, Weidong

    2018-04-18

    Ambient light has a vital impact on mood and cognitive functions. Blue light has been previously reported to play a salient role in the antidepressant effect via melanopsin. Whether blue light filtered white light (BFW) affects mood and cognitive functions remains unclear. The present study aimed to investigate whether BFW led to depression-like symptoms and cognitive deficits including spatial learning and memory abilities in rats, and whether they were associated with the light-responsive function in retinal explants. Male Sprague-Dawley albino rats were randomly divided into 2 groups (n = 10) and treated with a white light-emitting diode (LED) light source and BFW light source, respectively, under a standard 12 : 12 h L/D condition over 30 days. The sucrose consumption test, forced swim test (FST) and the level of plasma corticosterone (CORT) were employed to evaluate depression-like symptoms in rats. Cognitive functions were assessed by the Morris water maze (MWM) test. A multi-electrode array (MEA) system was utilized to measure electro-retinogram (ERG) responses induced by white or BFW flashes. The effect of BFW over 30 days on depression-like responses in rats was indicated by decreased sucrose consumption in the sucrose consumption test, an increased immobility time in the FST and an elevated level of plasma CORT. BFW led to temporary spatial learning deficits in rats, which was evidenced by prolonged escape latency and swimming distances in the spatial navigation test. However, no changes were observed in the short memory ability of rats treated with BFW. The micro-ERG results showed a delayed implicit time and reduced amplitudes evoked by BFW flashes compared to the white flash group. BFW induces depression-like symptoms and temporary spatial learning deficits in rats, which might be closely related to the impairment of light-evoked output signals in the retina.

  20. Staring at the Cold Sun: Blue Light Regulation Is Distributed within the Genus Acinetobacter

    Science.gov (United States)

    Golic, Adrián; Vaneechoutte, Mario; Nemec, Alexandr; Viale, Alejandro M.; Actis, Luis A.; Mussi, María Alejandra

    2013-01-01

    We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD)-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1) BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility. PMID:23358859

  1. Staring at the cold sun: blue light regulation is distributed within the genus Acinetobacter.

    Directory of Open Access Journals (Sweden)

    Adrián Golic

    Full Text Available We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1 BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility.

  2. Reducing Short-Wavelength Blue Light in Dry Eye Patients with Unstable Tear Film Improves Performance on Tests of Visual Acuity.

    Science.gov (United States)

    Kaido, Minako; Toda, Ikuko; Oobayashi, Tomoo; Kawashima, Motoko; Katada, Yusaku; Tsubota, Kazuo

    2016-01-01

    To investigate whether suppression of blue light can improve visual function in patients with short tear break up time (BUT) dry eye (DE). Twenty-two patients with short BUT DE (10 men, 12 women; mean age, 32.4 ± 6.4 years; age range, 23-43 years) and 18 healthy controls (10 men, 8 women; mean age, 30.1 ± 7.4 years; age range, 20-49 years) underwent functional visual acuity (VA) examinations with and without wearing eyeglasses with 50% blue light blocked lenses. The functional VA parameters were starting VA, functional VA, and visual maintenance ratio. The baseline mean values (logarithm of the minimum angle of resolution, logMAR) of functional VA and the visual maintenance ratio were significantly worse in the DE patients than in the controls (P 0.05). The DE patients had significant improvement in mean functional VA and visual maintenance ratio while wearing the glasses (P 0.05). Protecting the eyes from short-wavelength blue light may help to ameliorate visual impairment associated with tear instability in patients with DE. This finding represents a new concept, which is that the blue light exposure might be harmful to visual function in patients with short BUT DE.

  3. Reducing Short-Wavelength Blue Light in Dry Eye Patients with Unstable Tear Film Improves Performance on Tests of Visual Acuity.

    Directory of Open Access Journals (Sweden)

    Minako Kaido

    Full Text Available To investigate whether suppression of blue light can improve visual function in patients with short tear break up time (BUT dry eye (DE.Twenty-two patients with short BUT DE (10 men, 12 women; mean age, 32.4 ± 6.4 years; age range, 23-43 years and 18 healthy controls (10 men, 8 women; mean age, 30.1 ± 7.4 years; age range, 20-49 years underwent functional visual acuity (VA examinations with and without wearing eyeglasses with 50% blue light blocked lenses. The functional VA parameters were starting VA, functional VA, and visual maintenance ratio.The baseline mean values (logarithm of the minimum angle of resolution, logMAR of functional VA and the visual maintenance ratio were significantly worse in the DE patients than in the controls (P 0.05. The DE patients had significant improvement in mean functional VA and visual maintenance ratio while wearing the glasses (P 0.05.Protecting the eyes from short-wavelength blue light may help to ameliorate visual impairment associated with tear instability in patients with DE. This finding represents a new concept, which is that the blue light exposure might be harmful to visual function in patients with short BUT DE.

  4. Lighting considerations in controlled environments for nonphotosynthetic plant responses to blue and ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, M.M.; Flint, S.D. [Utah State Univ., Logan, UT (United States)

    1994-12-31

    This essay will consider both physical and photobiological aspects of controlled environment lighting in the spectral region beginning in the blue and taken to the normal limit of the solar spectrum in the ultraviolet. The primary emphasis is directed to questions of plant response to sunlight. Measurement and computations used in radiation dosimetry in this part of the spectrum are also briefly treated. Because of interest in the ozone depletion problem, there has been some activity in plant UV-B research and there are several recent reviews available. Some aspects of growth chamber lighting as it relates to UV-B research were covered earlier. Apart from work related to the blue/UV-A receptor, less attention has been given to UV-A responses.

  5. Influence of Pre-trimethylindium flow treatment on blue light emitting diode

    International Nuclear Information System (INIS)

    Xu, Bing; Zhao, Jun Liang; Dai, Hai Tao; Wang, Shu Guo; Lin, Ray-Ming; Chu, Fu-Chuan; Huang, Chou-Hsiung; Yu, Sheng-Fu; Sun, Xiao Wei

    2014-01-01

    The effects of Pre-trimethylindium (TMIn) flow treatment prior to quantum well growth on blue light emitting diode properties were investigated. High-resolution X-ray diffraction indicated that Pre-TMIn flow treatment did not change the composition of indium in quantum wells, but influenced electrical and optical properties of blue light emitting diode. Electroluminescence exhibited redshift with increasing TMIn treatment time. Though, the forward voltage became a little larger with longer Pre-TMIn treatment time due to the slight phase separation and indium aggregation, the efficiency droop of the device was improved effectively. - Highlights: • Pre-trimethylindium treatment can lead to longer wavelength. • External quantum efficiency can be improved effectively. • Electrical properties are not decreased using Pre-trimethylindium treatment

  6. Influence of Pre-trimethylindium flow treatment on blue light emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Bing; Zhao, Jun Liang [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Dai, Hai Tao, E-mail: htdai@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Wang, Shu Guo [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Lin, Ray-Ming, E-mail: rmlin@mail.cgu.edu.tw [Graduate Institute of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan 333, Taiwan (China); Chu, Fu-Chuan; Huang, Chou-Hsiung [Graduate Institute of Electronic Engineering and Green Technology Research Center, Chang Gung University, Taoyuan 333, Taiwan (China); Yu, Sheng-Fu [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Sun, Xiao Wei, E-mail: xwsun@sustc.edu.cn [South University of Science and Technology of China, Shenzhen, Guangdong (China)

    2014-01-31

    The effects of Pre-trimethylindium (TMIn) flow treatment prior to quantum well growth on blue light emitting diode properties were investigated. High-resolution X-ray diffraction indicated that Pre-TMIn flow treatment did not change the composition of indium in quantum wells, but influenced electrical and optical properties of blue light emitting diode. Electroluminescence exhibited redshift with increasing TMIn treatment time. Though, the forward voltage became a little larger with longer Pre-TMIn treatment time due to the slight phase separation and indium aggregation, the efficiency droop of the device was improved effectively. - Highlights: • Pre-trimethylindium treatment can lead to longer wavelength. • External quantum efficiency can be improved effectively. • Electrical properties are not decreased using Pre-trimethylindium treatment.

  7. Applications of Blue Light-curing Acrylic Resin to Forensic Sample Preparation and Microtomy.

    Science.gov (United States)

    Groves, Ethan; Palenik, Christopher S

    2016-03-01

    This study discusses the results of an evaluation of a one-part blue light-curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light-curing acrylic resins provide the desired properties of an embedding medium, generate high-quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory. © 2015 American Academy of Forensic Sciences.

  8. Increased antioxidant activity and changes in phenolic profile of Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) specimens grown under supplemental blue light.

    Science.gov (United States)

    Nascimento, Luana B S; Leal-Costa, Marcos V; Coutinho, Marcela A S; Moreira, Nattacha dos S; Lage, Celso L S; Barbi, Nancy dos S; Costa, Sônia S; Tavares, Eliana S

    2013-01-01

    Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV-A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV-A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV-A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue-light plant extracts revealed a higher proportion of the major flavonoid quercetin 3-O-α-L-arabinopyranosyl (1→2) α-L-rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  9. Light perception in two strictly subterranean rodents: life in the dark or blue?

    Directory of Open Access Journals (Sweden)

    Ondrej Kott

    Full Text Available BACKGROUND: The African mole-rats (Bathyergidae, Rodentia are strictly subterranean, congenitally microphthalmic rodents that are hardly ever exposed to environmental light. Because of the lack of an overt behavioural reaction to light, they have long been considered to be blind. However, recent anatomical studies have suggested retention of basic visual capabilities. In this study, we employed behavioural tests to find out if two mole-rat species are able to discriminate between light and dark, if they are able to discriminate colours and, finally, if the presence of light in burrows provokes plugging behaviour, which is assumed to have a primarily anti-predatory function. METHODOLOGY/PRINCIPAL FINDING: We used a binary choice test to show that the silvery mole-rat Heliophobius argenteocinereus and the giant mole-rat Fukomys mechowii exhibit a clear photoavoidance response to full-spectrum ("white", blue and green-yellow light, but no significant reaction to ultraviolet or red light during nest building. The mole-rats thus retain dark/light discrimination capabilities and a capacity to perceive short to medium-wavelength light in the photopic range of intensities. These findings further suggest that the mole-rat S opsin has its absorption maximum in the violet/blue part of the spectrum. The assay did not yield conclusive evidence regarding colour discrimination. To test the putative role of vision in bathyergid anti-predatory behaviour, we examined the reaction of mole-rats to the incidence of light in an artificial burrow system. The presence of light in the burrow effectively induced plugging of the illuminated tunnel. CONCLUSION/SIGNIFICANCE: Our findings suggest that the photopic vision is conserved and that low acuity residual vision plays an important role in predator avoidance and tunnel maintenance in the African mole-rats.

  10. Effects of a blue light-filtering intraocular lens on driving safety in glare conditions.

    Science.gov (United States)

    Gray, Rob; Hill, Warren; Neuman, Brooke; Houtman, Diane; Potvin, Richard

    2012-05-01

    To evaluate whether the previously established benefit of blue light-filtering intraocular lenses (IOLs) when driving in glare conditions is maintained in patients previously implanted with a blue light-filtering toric IOL. Department of Applied Psychology, Arizona State University, Mesa, Arizona, USA. Comparative case series. The study comprised patients with a blue light-filtering toric IOL (test IOL) or an ultraviolet (UV)-only filtering nontoric IOL (control IOL). All patients had good visual acuity and a valid driver's license. While wearing best spherocylindrical correction, patients performed left-turn maneuvers in front of oncoming traffic in a driving simulator. The safety margin was defined as the time to collision less the time taken to turn at an intersection with oncoming traffic. Measures were repeated with a glare source simulating low-angle sun conditions (daytime driving). Of the 33 evaluable patients, 18 had a test IOL and 15 had a control IOL. In the presence of glare, patients with test IOLs had significantly greater safety margins (mean 2.676 seconds ± 0.438 [SD]) than patients with control IOLs (mean 2.179 ± 0.343 seconds) and significantly lower glare susceptibility (P<.05). In no-glare and glare conditions, patients with test IOLs had significantly lower glare susceptibility than patients with control IOLs. The blue light-filtering toric IOL produced a significantly greater reduction in glare disability than the UV-only filtering nontoric IOL and increased the ability of drivers to safely execute left turns in low-sun conditions. Dr. Houtman is an employee of Alcon Laboratories, Inc. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. Spontaneous mutation 7B-1 in tomato impairs blue light-induced stomatal opening

    Czech Academy of Sciences Publication Activity Database

    Hlavinka, J.; Nauš, J.; Fellner, Martin

    2013-01-01

    Roč. 209, č. 2013 (2013), s. 75-80 ISSN 0168-9452 R&D Projects: GA ČR GD522/08/H003 Grant - others:GA ČR(CZ) GAP501/10/0785 Program:GA Institutional research plan: CEZ:AV0Z50380511 Keywords : ABA * Anion-channel blocker * Blue light Subject RIV: ED - Physiology Impact factor: 4.114, year: 2013

  12. Gap state related blue light emitting boron-carbon core shell structures

    International Nuclear Information System (INIS)

    Singh, Paviter; Kaur, Manpreet; Singh, Bikramjeet; Kaur, Gurpreet; Singh, Kulwinder; Kumar, Akshay; Kumar, Manjeet; Bala, Rajni; Thakur, Anup

    2016-01-01

    Boron-carbon core shell structures have been synthesized by solvo-thermal synthesis route. The synthesized material is highly pure. X-ray diffraction analysis confirms the reduction of reactants in to boron and carbon. Scanning Electron Microscopy (SEM) analysis showed that the shell is uniform with average thickness of 340 nm. Photo luminescence studies showed that the material is blue light emitting with CIE color coordinates: x=0.16085, y=0.07554.

  13. Advanced Oxidation of Tartrazine and Brilliant Blue with Pulsed Ultraviolet Light Emitting Diodes

    OpenAIRE

    Scott, Robert; Mudimbi, Patrick; Miller, Michael E.; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Harper, Willie F.

    2017-01-01

    This study investigated the effect of ultraviolet light-emitting diodes (UVLEDs) coupled with hydrogen peroxide as an advanced oxidation process (AOP) for the degradation of two test chemicals. Brilliant Blue FCF consistently exhibited greater degradation than tartrazine, with 83% degradation after 300 minutes at the 100% duty cycle compared with only 17% degradation of tartrazine under the same conditions. These differences are attributable to the structural properties of the compounds. Duty...

  14. White- and blue-light-emitting dysprosium(III) and terbium(III)-doped gadolinium titanate phosphors.

    Science.gov (United States)

    Antić, Ž; Kuzman, S; Đorđević, V; Dramićanin, M D; Thundat, T

    2017-06-01

    Here we report the synthesis and structural, morphological, and photoluminescence analysis of white- and blue-light-emitting Dy 3 + - and Tm 3 + -doped Gd 2 Ti 2 O 7 nanophosphors. Single-phase cubic Gd 2 Ti 2 O 7 nanopowders consist of compact, dense aggregates of nanoparticles with an average size of ~25 nm for Dy 3 + -doped and ~50 nm for Tm 3 + -doped samples. The photoluminescence results indicated that ultraviolet (UV) light excitation of the Dy 3 + -doped sample resulted in direct generation of white light, while a dominant yellow emission was obtained under blue-light excitation. Intense blue light was obtained for Tm 3 + -doped Gd 2 Ti 2 O 7 under UV excitation suggesting that this material could be used as a blue phosphor. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Blue emitting KSCN:xCe phosphor for solid state lighting

    Energy Technology Data Exchange (ETDEWEB)

    Chikte, Devayani, E-mail: devi.awade@gmail.com [G.N. Khalsa College, Matunga, Mumbai 400019 (India); Omanwar, S.K. [Department of Physics, S.G.B. Amravati University, Amravati (India); Moharil, S.V. [Department of Physics, R.T.M. Nagpur University, Nagpur 440010 (India)

    2014-01-15

    The intense blue emitting phosphor KSCN:xCe (x=0.005, 0.01, 0.02, 0.04) is synthesized by a simple, time saving, economical method of re-crystallization through aqueous solution at 353 K. Photoluminescence measurements showed that the said phosphor exhibits emission with good intensity peaking at 450 nm corresponding to d→f transitions of Ce{sup 3+} ion. The excitation spectra monitored at 450 nm shows small peak at 282 nm and broad intense excitation band peaking at 350 nm. The latter lies in near ultraviolet (350–410 nm) emission of UV LED. The phosphor KSCN:0.02Ce{sup 3+} shows CIE 1931 color coordinates as (0.1484, 0.0602) whereas the commercial blue phosphor BAM:Eu{sup 2+} shows the color co-ordinates as (0.1417, 0.1072), respectively, indicating better color purity for KSCN: 0.02Ce{sup 3+} compared to the BAM:Eu{sup 2+} phosphor. The color coordinates of KSCN: 0.02Ce{sup 3+} phosphor (0.1484, 0.0602) are nearer to the color coordinate for blue color suggested by the color systems EBUPAL/SECAM, sRGB Blue as well as Adobe blue(0.15, 0.06). -- Highlights: • Novel phosphor KSCN:xCe prepared for the first time. • Method is simple, time saving, economical, easy to handle. • Intense, blue, Characteristic Ce{sup 3+} emission at 450 nm. • nUV excitation, suitable for solid state lighting.

  16. 4-Gbit/s visible light communication link based on 16-QAM OFDM transmission over remote phosphor-film converted white light by using blue laser diode

    KAUST Repository

    Duran Retamal, Jose Ramon

    2015-12-21

    Visible Light Communication (VLC) as a new technology for ultrahigh-speed communication is still limited when using slow modulation light-emitting diode (LED). Alternatively, we present a 4-Gbit/s VLC system using coherent blue-laser diode (LD) via 16-quadrature amplitude modulation orthogonal frequency division multiplexing. By changing the composition and the optical-configuration of a remote phosphor-film the generated white light is tuned from cool day to neutral, and the bit error rate is optimized from 1.9 × 10-2 to 2.8 × 10-5 in a blue filter-free link due to enhanced blue light transmission in forward direction. Briefly, blue-LD is an alternative to LED for generating white light and boosting the data rate of VLC. © 2015 Optical Society of America.

  17. 4-Gbit/s visible light communication link based on 16-QAM OFDM transmission over remote phosphor-film converted white light by using blue laser diode

    KAUST Repository

    Duran Retamal, Jose Ramon; Oubei, Hassan M.; Janjua, Bilal; Chi, Yu-Chieh; Wang, Huai-Yung; Tsai, Cheng-Ting; Ng, Tien Khee; Hsieh, Dan-Hua; Kuo, Hao-Chung; Alouini, Mohamed-Slim; He, Jr-Hau; Lin, Gong-Ru; Ooi, Boon S.

    2015-01-01

    Visible Light Communication (VLC) as a new technology for ultrahigh-speed communication is still limited when using slow modulation light-emitting diode (LED). Alternatively, we present a 4-Gbit/s VLC system using coherent blue-laser diode (LD) via 16-quadrature amplitude modulation orthogonal frequency division multiplexing. By changing the composition and the optical-configuration of a remote phosphor-film the generated white light is tuned from cool day to neutral, and the bit error rate is optimized from 1.9 × 10-2 to 2.8 × 10-5 in a blue filter-free link due to enhanced blue light transmission in forward direction. Briefly, blue-LD is an alternative to LED for generating white light and boosting the data rate of VLC. © 2015 Optical Society of America.

  18. Novel Br-DPQ blue light-emitting phosphors for OLED.

    Science.gov (United States)

    Dahule, H K; Thejokalyani, N; Dhoble, S J

    2015-06-01

    A new series of blue light-emitting 2,4-diphenylquinoline (DPQ) substituted blue light-emitting organic phosphors namely, 2-(4-methoxy-phenyl)-4-phenyl-quinoline (OMe-DPQ), 2-(4-methyl-phenyl)-4-phenylquinoline (M-DPQ), and 2-(4-bromo-phenyl)-4-phenylquinoline (Br-DPQ) were synthesized by substituting methoxy, methyl and bromine at the 2-para position of DPQ, respectively by Friedländer condensation of 2-aminobenzophenone and corresponding acetophenone. The synthesized phosphors were characterized by different techniques, e.g., Fourier transform infra-red (FTIR), differential scanning calorimeter (DSC), UV-visible absorption and photoluminescence spectra. FTIR spectra confirms the presence of chemical groups such as C=O, NH, or OH in all the three synthesized chromophores. DSC studies show that these complexes have good thermal stability. Although they are low-molecular-weight organic compounds, they have the potential to improve the stability and operating lifetime of a device made out of these complexes. The synthesized polymeric compounds demonstrate a bright emission in the blue region in the wavelength range of 405-450 nm in solid state. Thus the attachment of methyl, methoxy and bromine substituents to the diphenyl quinoline ring in these phosphors results in colour tuning of the phosphorescence. An electroluminescence (EL) cell of Br-DPQ phosphor was made and its EL behaviour was studied. A brightness-voltage characteristics curve of Br-DPQ cell revealed that EL begins at 400 V and then the brightness increases exponentially with applied AC voltage, while current-voltage (I-V) characteristics revealed that the turn on voltage of the fabricated EL cell was 11 V. Hence this phosphor can be used as a promising blue light material for electroluminescent devices. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Study on the light leakage mechanism of a blue phase liquid crystal cell with oblique interfaces

    International Nuclear Information System (INIS)

    Yoon, Sukin; Jeong, Heon; Lee, Seung Hee; Yang, Gyu Hyung; Nayek, Prasenjit; Hong, Seung Ho; Lee, Hyeok Jin; Shin, Sung-Tae

    2012-01-01

    The mechanism of light leakage in the dark state of a blue phase liquid crystal display cell which has protruded electrodes was investigated. We have performed a hybrid numerical simulation by combining the geometrical optics with the extended Jones matrix method. The light leakage in the cell was caused by changes in the polarization state which has been explained by the asymmetric amplitude change of transverse electric and transverse magnetic fields at the oblique interface and the change in an effective angle between crossed polarizers by the light path refraction. Based on our analysis, light leakage can be suppressed by the matching of the refractive indices of adjacent materials to the interface of the protruded electrodes whose surfaces are not parallel to the substrate. (paper)

  20. Influence of Green, Red and Blue Light Emitting Diodes on Multiprotein Complex Proteins and Photosynthetic Activity under Different Light Intensities in Lettuce Leaves (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Sowbiya Muneer

    2014-03-01

    Full Text Available The objective of this study was to investigate the response of light emitting diodes (LEDs at different light intensities (70 and 80 for green LEDs, 88 and 238 for red LEDs and 80 and 238 μmol m−2 s−1 for blue LEDs at three wavelengths in lettuce leaves. Lettuce leaves were exposed to (522 nm, red (639 nm and blue (470 nm LEDs of different light intensities. Thylakoid multiprotein complex proteins and photosynthetic metabolism were then investigated. Biomass and photosynthetic parameters increased with an increasing light intensity under blue LED illumination and decreased when illuminated with red and green LEDs with decreased light intensity. The expression of multiprotein complex proteins including PSII-core dimer and PSII-core monomer using blue LEDs illumination was higher at higher light intensity (238 μmol m−2 s−1 and was lowered with decreased light intensity (70–80 μmol m−2 s−1. The responses of chloroplast sub-compartment proteins, including those active in stomatal opening and closing, and leaf physiological responses at different light intensities, indicated induced growth enhancement upon illumination with blue LEDs. High intensity blue LEDs promote plant growth by controlling the integrity of chloroplast proteins that optimize photosynthetic performance in the natural environment.

  1. Absorption and fluorescence spectroscopic characterisation of the circadian blue-light photoreceptor cryptochrome from Drosophila melanogaster (dCry)

    Science.gov (United States)

    Shirdel, J.; Zirak, P.; Penzkofer, A.; Breitkreuz, H.; Wolf, E.

    2008-09-01

    The absorption and fluorescence behaviour of the circadian blue-light photoreceptor cryptochrome from Drosophila melanogaster (dCry) in a pH 8 aqueous buffer solution is studied. The flavin adenine dinucleotide (FAD) cofactor of dCry is identified to be present in its oxidized form (FAD ox), and the 5,10-methenyltetrahydrofolate (MTHF) cofactor is found to be hydrolyzed and oxidized to 10-formyldihydrofolate (10-FDHF). The absorption and the fluorescence behaviour of dCry is investigated in the dark-adapted (receptor) state, the light-adapted (signalling) state, and under long-time violet light exposure. Photo-excitation of FAD ox in dCry causes a reductive electron transfer to the formation of anionic FAD semiquinone (FAD rad - ), and photo-excitation of the generated FAD rad - causes an oxidative electron transfer to the back formation of FAD ox. In light adapted dCry a photo-induced equilibrium between FAD ox and FAD rad - exists. The photo-cycle dynamics of signalling state formation and recovery is discussed. Quantum yields of photo-induced signalling state formation of about 0.2 and of photo-induced back-conversion of about 0.2 are determined. A recovery of FAD rad - to FAD ox in the dark with a time constant of 1.6 min at room temperature is found.

  2. Damage threshold in adult rabbit eyes after scleral cross-linking by riboflavin/blue light application.

    Science.gov (United States)

    Iseli, Hans Peter; Körber, Nicole; Karl, Anett; Koch, Christian; Schuldt, Carsten; Penk, Anja; Liu, Qing; Huster, Daniel; Käs, Josef; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

    2015-10-01

    Several scleral cross-linking (SXL) methods were suggested to increase the biomechanical stiffness of scleral tissue and therefore, to inhibit axial eye elongation in progressive myopia. In addition to scleral cross-linking and biomechanical effects caused by riboflavin and light irradiation such a treatment might induce tissue damage, dependent on the light intensity used. Therefore, we characterized the damage threshold and mechanical stiffening effect in rabbit eyes after application of riboflavin combined with various blue light intensities. Adult pigmented and albino rabbits were treated with riboflavin (0.5 %) and varying blue light (450 ± 50 nm) dosages from 18 to 780 J/cm(2) (15 to 650 mW/cm(2) for 20 min). Scleral, choroidal and retinal tissue alterations were detected by means of light microscopy, electron microscopy and immunohistochemistry. Biomechanical changes were measured by shear rheology. Blue light dosages of 480 J/cm(2) (400 mW/cm(2)) and beyond induced pathological changes in ocular tissues; the damage threshold was defined by the light intensities which induced cellular degeneration and/or massive collagen structure changes. At such high dosages, we observed alterations of the collagen structure in scleral tissue, as well as pigment aggregation, internal hemorrhages, and collapsed blood vessels. Additionally, photoreceptor degenerations associated with microglia activation and macroglia cell reactivity in the retina were detected. These pathological alterations were locally restricted to the treated areas. Pigmentation of rabbit eyes did not change the damage threshold after a treatment with riboflavin and blue light but seems to influence the vulnerability for blue light irradiations. Increased biomechanical stiffness of scleral tissue could be achieved with blue light intensities below the characterized damage threshold. We conclude that riboflavin and blue light application increased the biomechanical stiffness of scleral tissue at

  3. Fish with red fluorescent eyes forage more efficiently under dim, blue-green light conditions.

    Science.gov (United States)

    Harant, Ulrike Katharina; Michiels, Nicolaas Karel

    2017-04-20

    Natural red fluorescence is particularly conspicuous in the eyes of some small, benthic, predatory fishes. Fluorescence also increases in relative efficiency with increasing depth, which has generated speculation about its possible function as a "light organ" to detect cryptic organisms under bluish light. Here we investigate whether foraging success is improved under ambient conditions that make red fluorescence stand out more, using the triplefin Tripterygion delaisi as a model system. We repeatedly presented 10 copepods to individual fish (n = 40) kept under a narrow blue-green spectrum and compared their performance with that under a broad spectrum with the same overall brightness. The experiment was repeated for two levels of brightness, a shaded one representing 0.4% of the light present at the surface and a heavily shaded one with about 0.01% of the surface brightness. Fish were 7% more successful at catching copepods under the narrow, fluorescence-friendly spectrum than under the broad spectrum. However, this effect was significant under the heavily shaded light treatment only. This outcome corroborates previous predictions that fluorescence may be an adaptation to blue-green, heavily shaded environments, which coincides with the opportunistic biology of this species that lives in the transition zone between exposed and heavily shaded microhabitats.

  4. Degradation of phosphorescent blue organic light-emitting diodes (OLED); Degradation der phosphoreszenten blauen organischen Leuchtdioden

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Chien-Shu

    2011-07-01

    Phosphorescent organic materials harvest singlet and triplet excitons through inter-system crossing and improve the efficiency of organic light-emitting diodes (OLEDs). This improvement increases the potential of OLEDs, particularly white phosphorescent OLEDs (PHOLEDs), for lighting application. Although much progress has been made in the development of white PHOLEDs, the lifetime of phosphorescent emitters, especially the blue emitter, still needs to be improved. This thesis discusses the developments of blue PHOLEDs and investigations of degradation mechanisms. For development of blue PHOLEDs, two phosphorescent blue emitters were investigated: commercially available FIrpic and B1 provided by BASF. By varying the matrix and blocker materials, diode efficiency and lifetime have been investigated and improved. Blue PHOLEDs with emitter B1 show better efficiency and lifetime than devices with FIrpic. From lifetime measurement with constant DC current density, intrinsic degradation including luminance loss and voltage increase on both FIrpic and B1 PHOLEDs was observed. Photoluminescence measurement shows degradation in the emitting layers. To investigate the degradation of emitter layers, single-carrier devices with emitter systems or pure matrix materials were fabricated. Degradation on these devices was investigated by applying constant DC current, UV-irradiation and combination of both. We found that due to excited states (excitons), FIrpic molecules become unstable and polarons would enhance the degradation of FIrpic during DC operation and UV-excitation. To investigate the impact the exciton formation and exciton decay have on the degradation of FIrpic molecules, red phosphorescent emitter Ir(MDQ){sub 2}(acac) was doped in blue emitter layer TCTA:20% FIrpic. The doping concentration of Ir(MDQ){sub 2}(acac) was much lower than FIrpic to ensure that most of the exciton formation occurred on FIrpic molecules. Lower triplet energy of Ir(MDQ){sub 2}(acac) molecules

  5. Low-intensity blue-enriched white light (750 lux) and standard bright light (10 000 lux) are equally effective in treating SAD. A randomized controlled study

    NARCIS (Netherlands)

    Meesters, Ybe; Dekker, Vera; Schlangen, Luc J. M.; Bos, Elske H.; Ruiter, Martine J.

    2011-01-01

    Background: Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT) of SAD with treatment using short-wavelength blue-enriched white light (BLT). Both treatments used the same

  6. Highly efficient greenish-blue platinum-based phosphorescent organic light-emitting diodes on a high triplet energy platform

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y. L., E-mail: yilu.chang@mail.utoronto.ca; Gong, S., E-mail: sgong@chem.utoronto.ca; White, R.; Lu, Z. H., E-mail: zhenghong.lu@utoronto.ca [Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, Ontario M5S 3E4 (Canada); Wang, X.; Wang, S., E-mail: wangs@chem.queensu.ca [Department of Chemistry, Queen' s University, 90 Bader Lane, Kingston, Ontario K7L 3N6 (Canada); Yang, C. [Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2014-04-28

    We have demonstrated high-efficiency greenish-blue phosphorescent organic light-emitting diodes (PHOLEDs) based on a dimesitylboryl-functionalized C^N chelate Pt(II) phosphor, Pt(m-Bptrz)(t-Bu-pytrz-Me). Using a high triplet energy platform and optimized double emissive zone device architecture results in greenish-blue PHOLEDs that exhibit an external quantum efficiency of 24.0% and a power efficiency of 55.8 lm/W. This record high performance is comparable with that of the state-of-the-art Ir-based sky-blue organic light-emitting diodes.

  7. Treatment of attention deficit hyperactivity disorder insomnia with blue wavelength light-blocking glasses

    Directory of Open Access Journals (Sweden)

    Fargason RE

    2013-01-01

    Full Text Available Rachel E Fargason, Taylor Preston, Emily Hammond, Roberta May, Karen L GambleDepartment of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USABackground: The aim of this study was to examine a nonmedical treatment alternative to medication in attention deficit hyperactivity disorder (ADHD insomnia, in which blue wavelength light-blocking glasses are worn during the evening hours to counteract the phase-delaying effect of light. Outcome measures included sleep quality and midsleep time. The capacity of ADHD subjects to comply with treatment using the glasses was assessed.Methods: Daily bedtime, wake-up time, and compliance diaries were used to assess sleep quality and timing during a baseline observation week and a 2-week intervention period. The Pittsburgh Sleep Quality Index (PSQI was administered following baseline and intervention. The intervention protocol consisted of use of blue wavelength-blocking glasses and a moderate lighting environment during evening hours.Results: Partial and variable compliance were noted, with only 14 of 22 subjects completing the study due to nonadherence with wearing the glasses and diary completion. Despite the minimum 3-hour recommendation, glasses were worn, on average, for 2.4 hours daily. Lighting was reduced for only 58.7% of the evening. Compared with baseline, the intervention resulted in significant improvement in global PSQI scores, PSQI subcomponent scores, and sleep diary measures of morning refreshment after sleep (P = 0.037 and night-time awakenings (P = 0.015. Global PSQI scores fell from 11.15 to 4.54, dropping below the cut-off score of 5 for clinical insomnia. The more phase-delayed subjects, ie, those with an initial midsleep time after 4:15 am, trended towards an earlier midsleep time by 43.2 minutes following the intervention (P = 0.073. Participants reported less anxiety following the intervention (P = 0.048.Conclusions

  8. Quantifying the blue shift in the light absorption of small gold nanoparticles

    International Nuclear Information System (INIS)

    Tsekov, Roumen; Georgiev, Peter; Simeonova, Silviya; Balashev, Konstantin

    2017-01-01

    The dependence of the surface plasmons resonance (SPR) frequency on the size of gold nanoparticles (GNPs) is experimentally studied. The measured data for the SPR frequency by UV-Vis spectroscopy and GNPs diameter by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) are collected in the course of classical citrate GNPs synthesis. The relationship between the GNPs size and the blue shift of the light absorption is presented. They are fitted by an equation with a single free parameter, the dielectric permittivity of the surrounding media. Thus, the refractive index of the surrounding media is determined, which characterizes the GNPs surface shell. Key words: Gold nanoparticles (GNPs), Surface plasmon resonance (SPR), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM)

  9. Quantifying light exposure patterns in young adult students

    Science.gov (United States)

    Alvarez, Amanda A.; Wildsoet, Christine F.

    2013-08-01

    Exposure to bright light appears to be protective against myopia in both animals (chicks, monkeys) and children, but quantitative data on human light exposure are limited. In this study, we report on a technique for quantifying light exposure using wearable sensors. Twenty-seven young adult subjects wore a light sensor continuously for two weeks during one of three seasons, and also completed questionnaires about their visual activities. Light data were analyzed with respect to refractive error and season, and the objective sensor data were compared with subjects' estimates of time spent indoors and outdoors. Subjects' estimates of time spent indoors and outdoors were in poor agreement with durations reported by the sensor data. The results of questionnaire-based studies of light exposure should thus be interpreted with caution. The role of light in refractive error development should be investigated using multiple methods such as sensors to complement questionnaires.

  10. Proteomic analysis of blue light-induced twining response in Cuscuta australis.

    Science.gov (United States)

    Li, Dongxiao; Wang, Liangjiang; Yang, Xiaopo; Zhang, Guoguang; Chen, Liang

    2010-01-01

    The parasitic plant Cuscuta australis (dodder) invades a variety of species by entwining the stem and leaves of a host and developing haustoria. The twining response prior to haustoria formation is regarded as the first sign for dodders to parasitize host plants, and thus has been the focus of studies on the host-parasite interaction. However, the molecular mechanism is still poorly understood. In the present work, we have investigated the different effects of blue and white light on the twining response, and identified a set of proteins that were differentially expressed in dodder seedlings using a proteomic approach. Approximately 1,800 protein spots were detected on each 2-D gel, and 47 spots with increased or decreased protein levels were selected and analyzed with MALDI-TOF-MS. Peptide mass fingerprints (PMFs) obtained for these spots were used for protein identification through cross-species database searches. The results suggest that the blue light-induced twining response in dodder seedlings may be mediated by proteins involved in light signal transduction, cell wall degradation, cell structure, and metabolism.

  11. Organic light-emitting diodes with direct contact-printed red, green, blue, and white light-emitting layers

    Science.gov (United States)

    Chen, Sun-Zen; Peng, Shiang-Hau; Ting, Tzu-Yu; Wu, Po-Shien; Lin, Chun-Hao; Chang, Chin-Yeh; Shyue, Jing-Jong; Jou, Jwo-Huei

    2012-10-01

    We demonstrate the feasibility of using direct contact-printing in the fabrication of monochromatic and polychromatic organic light-emitting diodes (OLEDs). Bright devices with red, green, blue, and white contact-printed light-emitting layers with a respective maximum luminance of 29 000, 29 000, 4000, and 18 000 cd/m2 were obtained with sound film integrity by blending a polymeric host into a molecular host. For the red OLED as example, the maximum luminance was decreased from 29 000 to 5000 cd/m2 as only the polymeric host was used, or decreased to 7000 cd/m2 as only the molecular host was used. The markedly improved device performance achieved in the devices with blended hosts may be attributed to the employed polymeric host that contributed a good film-forming character, and the molecular host that contributed a good electroluminescence character.

  12. Female Sprague Dawley Rats Show Impaired Spatial Memory in the 8-Arm Radial Maze under Dim Blue and Red Light

    Directory of Open Access Journals (Sweden)

    Michael Pirchl

    2010-01-01

    Full Text Available Light intensity and wavelength strongly influence mood and cognition in humans and rodent animal models. The aim of the present study was to explore if dim white (7.6–17.7 lux , blue (1.3–2.3 lux, and red light (0.8–1.4 lux affect spatial memory of male and female Sprague Dawley rats in the 8-arm radial maze. Our data show that spatial memory significantly improved within 5 daily learning sessions (each 5 trials under dim white light, which was not different between male and female rats. However, dim blue and red light significantly reduced spatial learning of female rats in the 8-arm radial maze in the last training session (session 5. In conclusion, we suggest that female Sprague Dawley rats show reduced learning under blue and red light.

  13. Non-invasive plant growth measurements for detection of blue-light dose response of stem elongation in Chrysanthemum morifolium

    DEFF Research Database (Denmark)

    Kjær, Katrine Heinsvig

    2012-01-01

    . In the present study a non-invasive plant growth sensor (PlantEye, Phenospex B.V, Heerlen, NL) was tested in analysing changes in diurnal stem elongation patterns and plant height in response to the spectral quality of the light environment. Plants were grown in four different LED supplemental lighting...... treatments with 0%, 12.5%, 18.5% and 22.5% blue light under greenhouse conditions in winter (18 h day/4 h night). The non-invasive measurements were carried out automatically every four hour with three repetitions, and supported by manual measurements of plant height every third day. A strong linear relation...... between the non-invasive measurements and manual measurements of plant height was achieved, and a blue-light dose-response showing a decrease in plant height in relation to an increase in blue light was demonstrated. However, the non-invasive plant growth sensor was not able to distinguish between diurnal...

  14. OSL response bleaching of BeO samples, using fluorescent light and blue LEDs

    International Nuclear Information System (INIS)

    Groppo, Daniela Piai; Caldas, Linda V.E.

    2015-01-01

    The optically stimulated luminescence (OSL) is widely used as a dosimetric technique for many applications. In this work, the OSL response bleaching of BeO samples was studied. The samples were irradiated using a beta radiation source ( 90 Sr+ 90 Y); the bleaching treatments (fluorescent light and blue LEDs) were performed, and the results were compared. Various optical treatment time intervals were tested until reaching the complete bleaching of the OSL response. The best combination of the time interval and bleaching type was analyzed. (author)

  15. Efficiency and stability of a phosphor-conversion white light source using a blue laser diode

    Directory of Open Access Journals (Sweden)

    G. Ledru

    2014-10-01

    Full Text Available A white light source using direct phosphor-conversion excited by a blue laser diode is presented. In this preliminary study we have investigated the influence of phosphor’s thickness and operating current of the laser diode over the (x, y chromaticity coordinates, Correlated Color Temperature (CCT and Color Rendering Index (CRI. The best values found were 4000 K and 94. A 40 lm/W luminous efficacy was achieved together with a CRI close to 90 for an operating current of 0.8 A. Those values, to the best of our knowledge, were not previously reported in the literature.

  16. Characterisation of blue-light stimulated luminescence components in different quartz samples: Implications for dose measurement

    DEFF Research Database (Denmark)

    Jain, M.; Murray, A.S.; Bøtter-Jensen, L.

    2003-01-01

    -aliquot dose-evaluation protocols seem to be relatively free of complications when applied to quartz dominated by the fast OSL component coming from 325degreesC TL region, but this may not be true for quartz in which other components are more significant. An adequate understanding of how different OSL...... results from measurement of (a) sensitisation, (b) thermal stability, (c) recuperation, and (d) infrared response as a function of stimulation temperature from 3 different samples of sedimentary quartz selected on the basis of relative OSL contribution from different blue light stimulated linearly...

  17. Changes in plasma membrane aquaporin gene expression under osmotic stress and blue light in tomato

    Czech Academy of Sciences Publication Activity Database

    Balarynová, Jana; Danihlík, J.; Fellner, Martin

    2018-01-01

    Roč. 40, č. 2 (2018), č. článku 27. ISSN 0137-5881 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : male-sterile mutant * arabidopsis-thaliana * seed-germination * abscisic-acid * solanum-lycopersicon * nitric-oxide * 7b-1 * protein * hypocotyl * responses * Tomato * Seed * Aquaporins * Blue light * 7B-1 mutant * Mannitol * PIPs Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Genetics and heredity (medical genetics to be 3) Impact factor: 1.364, year: 2016

  18. Photomultipliers gain monitoring at the one percent level with a blue light pulser

    International Nuclear Information System (INIS)

    Berger, J.; Bermond, M.; Besson, P.; Favier, J.; Pessard, H.; Poulet, M.

    1988-07-01

    We describe a method and an experimental layout allowing the monitoring of photomultipliers gain. We use artificial blue light (Spark-gap with filter: 436 ± 20 nm) and three reference detectors. Short term and long term measurements are presented. The results indicate a precision better than 0.5% for the short term and 1.4% for the long term determinations. This gain monitoring system has been developed for a new neutrino oscillation reactor experiment (600 photomultipliers) starting at the Bugey nuclear plant

  19. OSL response bleaching of BeO samples, using fluorescent light and blue LEDs

    International Nuclear Information System (INIS)

    Groppo, D P; Caldas, L V E

    2016-01-01

    The optically stimulated luminescence (OSL) is widely used as a dosimetric technique for many applications. In this work, the OSL response bleaching of BeO samples was studied. The samples were irradiated using a beta radiation source ("9"0Sr+"9"0Y); the bleaching treatments (fluorescent light and blue LEDs) were performed, and the results were compared. Various optical treatment time intervals were tested until reaching the complete bleaching of the OSL response. The best combination of the time interval and bleaching type was analyzed. (paper)

  20. Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses.

    Science.gov (United States)

    da Costa, Marcelo Fernandes; Júnior, Augusto Paranhos; Lottenberg, Claudio Luiz; Castro, Leonardo Cunha; Ventura, Dora Fix

    2017-12-01

    The purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material. Monocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions. No difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found. Blue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

  1. High color rendering index white organic light-emitting diode using levofloxacin as blue emitter

    International Nuclear Information System (INIS)

    Miao Yan-Qin; Zhang Ai-Qin; Li Yuan-Hao; Wang Hua; Jia Hu-Sheng; Liu Xu-Guang; Gao Zhi-Xiang; Tsuboi Taijuf

    2015-01-01

    Levofloxacin (LOFX), which is well-known as an antibiotic medicament, was shown to be useful as a 452-nm blue emitter for white organic light-emitting diodes (OLEDs). In this paper, the fabricated white OLED contains a 452-nm blue emitting layer (thickness of 30 nm) with 1 wt% LOFX doped in CBP (4,4’-bis(carbazol-9-yl)biphenyl) host and a 584-nm orange emitting layer (thickness of 10 nm) with 0.8 wt% DCJTB (4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7, 7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran) doped in CBP, which are separated by a 20-nm-thick buffer layer of TPBi (2,2’,2”-(benzene-1,3,5-triyl)-tri(1-phenyl-1H-benzimidazole). A high color rendering index (CRI) of 84.5 and CIE chromaticity coordinates of (0.33, 0.32), which is close to ideal white emission CIE (0.333, 0.333), are obtained at a bias voltage of 14 V. Taking into account that LOFX is less expensive and the synthesis and purification technologies of LOFX are mature, these results indicate that blue fluorescence emitting LOFX is useful for applications to white OLEDs although the maximum current efficiency and luminance are not high. The present paper is expected to become a milestone to using medical drug materials for OLEDs. (paper)

  2. Efficient non-doped phosphorescent orange, blue and white organic light-emitting devices

    Science.gov (United States)

    Yin, Yongming; Yu, Jing; Cao, Hongtao; Zhang, Letian; Sun, Haizhu; Xie, Wenfa

    2014-10-01

    Efficient phosphorescent orange, blue and white organic light-emitting devices (OLEDs) with non-doped emissive layers were successfully fabricated. Conventional blue phosphorescent emitters bis [4,6-di-fluorophenyl]-pyridinato-N,C2'] picolinate (Firpic) and Bis(2,4-difluorophenylpyridinato) (Fir6) were adopted to fabricate non-doped blue OLEDs, which exhibited maximum current efficiency of 7.6 and 4.6 cd/A for Firpic and Fir6 based devices, respectively. Non-doped orange OLED was fabricated utilizing the newly reported phosphorescent material iridium (III) (pbi)2Ir(biq), of which manifested maximum current and power efficiency of 8.2 cd/A and 7.8 lm/W. The non-doped white OLEDs were achieved by simply combining Firpic or Fir6 with a 2-nm (pbi)2Ir(biq). The maximum current and power efficiency of the Firpic and (pbi)2Ir(biq) based white OLED were 14.8 cd/A and 17.9 lm/W.

  3. Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity.

    Science.gov (United States)

    Cheng, Chien-Wei; Chen, Liang-Yü; Chou, Chan-Wei; Liang, Ji-Yuan

    2015-07-01

    Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Photoluminescence studies of organic phosphor coated diffusing surface using blue inorganic light-emitting diode as excitation source

    International Nuclear Information System (INIS)

    Singh, Gyanendra; Mehta, Dalip Singh

    2013-01-01

    We report the studies on photoluminescence (PL) of organic phosphor coated on a diffusing surface using a blue inorganic light-emitting diode (LED) array as an excitation source. The organic phosphor composite coated diffuser was used to scatter the directional blue light from the LED array. Some of the blue light is absorbed by the organic phosphor composite and the phosphor molecules are excited and re-emit light at longer wavelengths due to the PL process. The output light consists of scattered blue light plus phosphor generated broadband yellow light, thus making white light. The diffuser was made up of a plastic substrate coated with an organic composite of small molecule fluorescent material zinc(II)bis(8-hydroxyquinoline) (Znq 2 ) doped with different percentages of electro-phosphorescent metal complex iridium(III)bis(2-methyldibenzo-[f, h] quinoxaline) (acetylacetonate) ([Ir(MDQ) 2 (acac)]). By means of changing the concentration and the thickness of the phosphor composite material the colour coordinates of white light were achieved. The CIE coordinates and correlated colour temperature were calculated for various thicknesses and phosphor composite concentrations and the results are reported. (paper)

  5. Abnormal environmental light exposure in the intensive care environment.

    Science.gov (United States)

    Fan, Emily P; Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C; Maas, Matthew B

    2017-08-01

    We sought to characterize ambient light exposure in the intensive care unit (ICU) environment to identify patterns of light exposure relevant to circadian regulation. A light monitor was affixed to subjects' bed at eye level in a modern intensive care unit and continuously recorded illuminescence for at least 24h per subject. Blood was sampled hourly and measured for plasma melatonin. Subjects underwent hourly vital sign and bedside neurologic assessments. Care protocols and the ICU environment were not modified for the study. A total of 67,324 30-second epochs of light data were collected from 17 subjects. Light intensity peaked in the late morning, median 64.1 (interquartile range 19.7-138.7) lux. The 75th percentile of light intensity exceeded 100lx only between 9AM and noon, and never exceeded 150lx. There was no correlation between melatonin amplitude and daytime, nighttime or total light exposure (Spearman's correlation coefficients all 0.5). Patients' environmental light exposure in the intensive care unit is consistently low and follows a diurnal pattern. No effect of nighttime light exposure was observed on melatonin secretion. Inadequate daytime light exposure in the ICU may contribute to abnormal circadian rhythms. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Effects of blue light irradiation on dental enamel remineralization in vitro

    International Nuclear Information System (INIS)

    Kato, Ilka Tiemy

    2009-01-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm 2 e 6.25 mL/mm 2 ). The lesions were irradiated with blue LED (l=455±20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm 2 , radiant exposure of 13.8 J/ c m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  7. Arabidopsis cryptochrome 1 is a soluble protein mediating blue light-dependent regulation of plant growth and development

    International Nuclear Information System (INIS)

    Lin ChenTao; Ahmad, M.; Cashmore, A.R.

    1996-01-01

    Cryptochrome 1 (CRY1) is a flavin-type blue type receptor of Arabidopsis thaliana which mediates inhibition of hypocotyl elongation. In the work described in this report it is demonstrated that CRY1 is a soluble protein expressed in both young seedlings grown either in the dark or under light, and in different organs of adult plants. The functional role of CRY1 was further investigated using transgenic Arabidopsis plants overexpressing CRY1. It is demonstrated that overexpression of CRY1 resulted in hypersensitivity to blue, UV-A, and green light for the inhibition of hypocotyl elongation response. Transgenic plants overexpressing CRY1 also exhibited a dwarf phenotype with reduced size in almost every organ. This was in keeping with the previous observation of reciprocal alterations found in hy4 mutant plants and is consistent with a hypothesis that CRY1 mediates a light-dependent process resulting in a general inhibitory effect on plant growth. In addition, transgenic plants overexpressing CRY1 showed increased anthocyanin accumulation in response to blue, UV-A, and green light in a fluence rate-dependent manner. This increase in anthocyanin accumulation in transgenic plants was shown to be concomitant with increased blue light-induction of CHS gene expression. It is concluded that CRY1 is a photoreceptor mediating blue light-dependent regulation of gene expression in addition to its affect on plant growth. (author)

  8. Enhanced quantum efficiency in blue-emitting polymer/dielectric nanolayer nanocomposite light-emitting devices

    International Nuclear Information System (INIS)

    Park, Jong Hyeok; Lim, Yong Taik; Park, O Ok; Yu, Jae-Woong; Kim, Jai Kyeong; Kim, Young Chul

    2004-01-01

    Light-emitting devices based on environmentally stable, blue-emitting polymer/dielectric nanolayer nanocomposites were fabricated by blending poly(di-octylfluorene) (PDOF) with organo-clay. By reducing the excimer formation that leads to long wavelength tails, the photoluminescence (PL) and electroluminescence (EL) color purity of the device was enhanced. When a conjugated polymer/dielectric nanolayer nanocomposite is applied to an EL device, we expect an electronic structure similar to the well-known quantum well in small nanodomains. The ratio of PDOF/organo-clay was regulated from 2:1 to 0.5:1 (w/w). The light-emitting device of 0.5:1 (w/w) blend demonstrated the highest quantum efficiency (QE), 0.72% (ph/el), which is ∼500 times higher value compared with that of the pure PDOF layer device. However, the driving voltage of the nanocomposite devices tended to increase with increasing organo-clay content

  9. Tunable blue organic light emitting diode based on aluminum calixarene supramolecular complex

    Science.gov (United States)

    Legnani, C.; Reyes, R.; Cremona, M.; Bagatin, I. A.; Toma, H. E.

    2004-07-01

    In this letter, the results of supramolecular organic light emitting diodes using a calix[4] arene complex thin film as emitter and electron transporting layer are presented. The devices were grown onto glass substrates coated with indium-tin-oxide layer and aluminum thick (150nm) cathode. By applying a dc voltage between the device electrodes in forward bias condition, a blue light emission in the active area of the device was observed. It was found that the electroluminescent emission peak can be tuned between 470 and 510nm changing the applied voltage bias from 4.3 to 5.4V. The observed tunable emission can be associated with an energy transfer from the calixarene compound.

  10. Light transmission through intraocular lenses with or without yellow chromophore (blue light filter) and its potential influence on functional vision in everyday environmental conditions.

    Science.gov (United States)

    Owczarek, Grzegorz; Gralewicz, Grzegorz; Skuza, Natalia; Jurowski, Piotr

    2016-01-01

    In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed.

  11. Efficient white organic light-emitting devices based on blue, orange, red phosphorescent dyes

    International Nuclear Information System (INIS)

    Chen Ping; Duan Yu; Xie Wenfa; Zhao Yi; Hou Jingying; Liu Shiyong; Zhang Liying; Li Bin

    2009-01-01

    We demonstrate efficient white organic light-emitting devices (WOLEDs) based on an orange phosphorescent iridium complex bis(2-(2-fluorphenyl)-1,3-benzothiozolato-N, C 2' )iridium(acetylacetonate) in combination with blue phosphorescent dye bis[(4, 6-difluorophenyl)-pyridinato-N,C 2 )](picolinato) Ir(III) and red phosphorescent dye bis[1-(phenyl)isoquinoline] iridium (III) acetylanetonate. By introducing a thin layer of 4, 7-diphenyl-1,10-phenanthroline between blue and red emission layers, the diffusion of excitons is confined and white light can be obtained. WOLEDs with the interlayer all have a higher colour rendering index (>82) than the device without it (76). One device has the maximum current efficiency of 17.6 cd A -1 and a maximum luminance of 39 050 cd m -2 . The power efficiency is 8.7 lm W -1 at 100 cd m -2 . Furthermore, the device has good colour stability and the CIE coordinates just change from (0.394, 0.425) to (0.390, 0.426) with the luminance increasing from 630 to 4200 cd m -2 .

  12. [The spectrogram characteristics of organic blue-emissive light-emitting excitated YAG : Ce phosphor].

    Science.gov (United States)

    Xi, Jian-Fei; Zhang, Fang-Hui; Mu, Qiang; Zhang, Mai-Li

    2011-09-01

    It is demonstrated that the panchromatic luminescence devices with organic blue-emissive light-emitting was fabricated. This technique used down conversion, which was already popular in inorganic power LEDs to obtain white light emission. A blue OLED device with a configuration of ITO/2T-NATA (30 nm)/AND : TBPe (50 Wt%, 40 nm)/Alq3 (100 nm)/LiF(1 nm)/Al(100 nm) was prepared via vacuum deposition process, and then coated with YAG : Ce phosphor layers of different thicknesses to obtain a controllable and uniform shape while the CIE coordinates were fine tuned. This development not only decreased steps of technics and degree of difficulty, but also applied the mature technology of phosphor. The results showed that steady spectrogram was obtained in the devices with phosphor, with a best performance of a maximum luminance of 13 840 cd x m(-2) which was about 2 times of that of the devices without phosphor; a maximum current efficiency of 17.3 cd x A(-1) was increased more two times more than the devices without phosphor. The emission spectrum could be adjusted by varying the concentration and thickness of the phosphor layers. Absoulte spectrogram of devices was in direct proportion with different driving current corresponding.

  13. A Study of Gibberellin Homeostasis and Cryptochrome-Mediated Blue Light Inhibition of Hypocotyl Elongation1[W][OA

    Science.gov (United States)

    Zhao, Xiaoying; Yu, Xuhong; Foo, Eloise; Symons, Gregory M.; Lopez, Javier; Bendehakkalu, Krishnaprasad T.; Xiang, Jing; Weller, James L.; Liu, Xuanming; Reid, James B.; Lin, Chentao

    2007-01-01

    Cryptochromes mediate blue light-dependent photomorphogenic responses, such as inhibition of hypocotyl elongation. To investigate the underlying mechanism, we analyzed a genetic suppressor, scc7-D (suppressors of cry1cry2), which suppressed the long-hypocotyl phenotype of the cry1cry2 (cryptochrome1/cryptochrome2) mutant in a light-dependent but wavelength-independent manner. scc7-D is a gain-of-expression allele of the GA2ox8 gene encoding a gibberellin (GA)-inactivating enzyme, GA 2-oxidase. Although scc7-D is hypersensitive to light, transgenic seedlings expressing GA2ox at a level higher than scc7-D showed a constitutive photomorphogenic phenotype, confirming a general role of GA2ox and GA in the suppression of hypocotyl elongation. Prompted by this result, we investigated blue light regulation of mRNA expression of the GA metabolic and catabolic genes. We demonstrated that cryptochromes are required for the blue light regulation of GA2ox1, GA20ox1, and GA3ox1 expression in transient induction, continuous illumination, and photoperiodic conditions. The kinetics of cryptochrome induction of GA2ox1 expression and cryptochrome suppression of GA20ox1 or GA3ox1 expression correlate with the cryptochrome-dependent transient reduction of GA4 in etiolated wild-type seedlings exposed to blue light. Therefore we propose that in deetiolating seedlings, cryptochromes mediate blue light regulation of GA catabolic/metabolic genes, which affect GA levels and hypocotyl elongation. Surprisingly, no significant change in the GA4 content was detected in the whole shoot samples of the wild-type or cry1cry2 seedlings grown in the dark or continuous blue light, suggesting that cryptochromes may also regulate GA responsiveness and/or trigger cell- or tissue-specific changes of the level of bioactive GAs. PMID:17644628

  14. [Blue-light induced expression of S-adenosy-L-homocysteine hydrolase-like gene in Mucor amphibiorum RCS1].

    Science.gov (United States)

    Gao, Ya; Wang, Shu; Fu, Mingjia; Zhong, Guolin

    2013-09-04

    To determine blue-light induced expression of S-adenosyl-L-homocysteine hydrolase-like (sahhl) gene in fungus Mucor amphibiorum RCS1. In the random process of PCR, a sequence of 555 bp was obtained from M. amphibiorum RCS1. The 555 bp sequence was labeled with digoxin to prepare the probe for northern hybridization. By northern hybridization, the transcription of sahhl gene was analyzed in M. amphibiorum RCS1 mycelia culture process from darkness to blue light to darkness. Simultaneously real-time PCR method was used to the sahhl gene expression analysis. Compared with the sequence of sahh gene from Homo sapiens, Mus musculus and some fungi species, a high homology of the 555 bp sequence was confirmed. Therefore, the preliminary confirmation has supported that the 555 bp sequence should be sahhl gene from M. amphibiorum RCS1. Under the dark pre-culture in 24 h, a large amounts of transcript of sahhl gene in the mycelia can be detected by northern hybridization and real-time PCR in the condition of 24 h blue light. But a large amounts of transcript of sahhl gene were not found in other detection for the dark pre-culture of 48 h, even though M. amphibiorum RCS1 mycelia were induced by blue light. Blue light can induce the expression of sahhl gene in the vigorous growth of M. amphibiorum RCS1 mycelia.

  15. Fluence dependence of the ultraviolet-light-induced accumulation of chalcone synthase mRNA and effects of blue and far-red light in cultured parsley

    International Nuclear Information System (INIS)

    Bruns, B.; Hahlbrock, K.; Schäfer, E.

    1986-01-01

    The fluence dependence of the time course of accumulation of chalcone synthase mRNA in ultraviolet (UV)-light-irradiated cell suspension cultures of parsley (Petroselinum crispum) and the additional effects of blue and far-red light have been investigated. Variations of the UV fluence had no detectable influence on the initial rate of increase in mRNA amount or translational activity, nor on the preceding lag period of approximately 3 h, but strongly influenced the duration of the transient increase. The effects were the same whether the fluence rate or the time of irradiation was varied to obtain a given fluence. Blue-light pretreatment of the cells resulted in increased amounts of mRNA and abolished the apparent lag period. This effect remained cryptic without the subsequent UV-light treatment. Irradiation with long-wavelength far-red light following UV-light pulses shortened the duration of the mRNA accumulation period. This effect was not altered by a preceding blue-light treatment. Thus, three photoreceptors, a UV-B receptor, a blue-light receptor and phytochrome, participate in the regulation of chalcone synthase mRNA accumulation in this system

  16. Large plasma-membrane depolarization precedes rapid blue-light-induced growth inhibition in cucumber

    Science.gov (United States)

    Spalding, E. P.; Cosgrove, D. J.

    1989-01-01

    Blue-light (BL)-induced suppression of elongation of etiolated Cucumis sativus L. hypocotyls began after a 30-s lag time, which was halved by increasing the fluence rate from 10 to 100 micromoles m-2 s-1. Prior to the growth suppression, the plasma-membrane of the irradiated cells depolarized by as much as 100 mV, then returned within 2-3 min to near its initial value. The potential difference measured with surface electrodes changed with an identical time course but opposite polarity. The lag time for the change in surface potential showed an inverse dependence on fluence rate, similar to the lag for the growth inhibition. Green light and red light caused neither the electrical response nor the rapid inhibition of growth. The depolarization by BL did not propagate to nonirradiated regions and exhibited a refractory period of about 10 min following a BL pulse. Fluence-response relationships for the electrical and growth responses provide correlational evidence that the plasma-membrane depolarization reflects an event in the transduction chain of this light-growth response.

  17. Effect of Stepwise Doping on Lifetime and Efficiency of Blue and White Phosphorescent Organic Light Emitting Diodes.

    Science.gov (United States)

    Lee, Song Eun; Lee, Ho Won; Lee, Seok Jae; Koo, Ja-ryong; Lee, Dong Hyung; Yang, Hyung Jin; Kim, Hye Jeong; Yoon, Seung Soo; Kim, Young Kwan

    2015-02-01

    We investigated a light emission mechanism of blue phosphorescent organic light emitting diodes (PHOLEDs), using a stepwise doping profile of 2, 8, and 14 wt.% within the emitting layer (EML). We fabricated several blue PHOLEDs with phosphorescent blue emitter iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C2]picolinate doped in N,N'-dicarbazolyl-3,5-benzene as a p-type host material. A blue PHOLED with the highest doping concentration as part of the EML close to an electron transporting layer showed a maximum luminous efficiency of 20.74 cd/A, and a maximum external quantum efficiency of 10.52%. This can be explained by effective electron injection through a highly doped EML side. Additionally, a white OLED based on the doping profile was fabricated with two thin red EMLs within a blue EML maintaining a thickness of 30 nm for the entire EML. Keywords: Blue Phosphorescent Organic Light Emitting Diodes, Stepwise Doping Structure, Charge Trapping Effect.

  18. High color rendering index white organic light-emitting diode using levofloxacin as blue emitter

    Science.gov (United States)

    Miao, Yan-Qin; Gao, Zhi-Xiang; Zhang, Ai-Qin; Li, Yuan-Hao; Wang, Hua; Jia, Hu-Sheng; Liu, Xu-Guang; Tsuboi, Taijuf

    2015-05-01

    Levofloxacin (LOFX), which is well-known as an antibiotic medicament, was shown to be useful as a 452-nm blue emitter for white organic light-emitting diodes (OLEDs). In this paper, the fabricated white OLED contains a 452-nm blue emitting layer (thickness of 30 nm) with 1 wt% LOFX doped in CBP (4,4’-bis(carbazol-9-yl)biphenyl) host and a 584-nm orange emitting layer (thickness of 10 nm) with 0.8 wt% DCJTB (4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran) doped in CBP, which are separated by a 20-nm-thick buffer layer of TPBi (2,2’,2”-(benzene-1,3,5-triyl)-tri(1-phenyl-1H-benzimidazole). A high color rendering index (CRI) of 84.5 and CIE chromaticity coordinates of (0.33, 0.32), which is close to ideal white emission CIE (0.333, 0.333), are obtained at a bias voltage of 14 V. Taking into account that LOFX is less expensive and the synthesis and purification technologies of LOFX are mature, these results indicate that blue fluorescence emitting LOFX is useful for applications to white OLEDs although the maximum current efficiency and luminance are not high. The present paper is expected to become a milestone to using medical drug materials for OLEDs. Project supported by the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-13-0927), the International Science & Technology Cooperation Program of China (Grant No. 2012DFR50460), the National Natural Science Foundation of China (Grant Nos. 21101111 and 61274056), and the Shanxi Provincial Key Innovative Research Team in Science and Technology, China (Grant No. 2012041011).

  19. Randomised controlled trial of the efficacy of a blue-enriched light intervention to improve alertness and performance in night shift workers.

    Science.gov (United States)

    Sletten, Tracey L; Ftouni, Suzanne; Nicholas, Christian L; Magee, Michelle; Grunstein, Ronald R; Ferguson, Sally; Kennaway, David J; O'Brien, Darren; Lockley, Steven W; Rajaratnam, Shantha M W

    2017-11-01

    Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. Participants were 71 night shift workers (42 males; 32.8±10.5 years) who worked at least 6 hours between 22:00 and 08:00 hours. Sleep-wake logs and wrist actigraphy were collected for 1-3 weeks, followed by 48-hour urine collection to measure the circadian 6-sulphatoxymelatonin (aMT6s) rhythm. On the night following at least two consecutive night shifts, workers attended a simulated night shift in the laboratory which included subjective and objective assessments of sleepiness and performance. Workers were randomly assigned for exposure to one of two treatment conditions from 23:00 hours to 07:00 hours: blue-enriched white light (17 000 K, 89 lux; n=36) or standard white light (4000 K, 84 lux; n=35). Subjective and objective sleepiness increased during the night shift in both light conditions (pnight shift workers, further research is needed in the selection of light properties to maximise the benefits. The Australian New Zealand Clinical Trials Registry ACTRN12610000097044 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=320845&isReview=true). © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Blue-light digital communication in underwater environments utilizing orbital angular momentum

    Science.gov (United States)

    Baghdady, Joshua; Miller, Keith; Osler, Sean; Morgan, Kaitlyn; Li, Wenzhe; Johnson, Eric; Cochenour, Brandon

    2016-05-01

    Underwater optical communication has recently become the topic of much investigation as the demands for underwater data transmission have rapidly grown in recent years. The need for reliable, high-speed, secure underwater communication has turned increasingly to blue-light optical solutions. The blue-green visible wavelength window provides an attractive solution to the problem of underwater data transmission thanks to its low attenuation, where traditional RF solutions used in free-space communications collapse. Beginning with GaN laser diodes as the optical source, this work explores the encoding and transmission of digital data across underwater environments of varying turbidities. Given the challenges present in an underwater environment, such as the mechanical and optical turbulences that make proper alignment difficult to maintain, it is desirable to achieve extremely high data rates in order to allow the time window of alignment between the transmitter and receiver to be as small as possible. In this paper, work is done to increase underwater data rates through the use of orbital angular momentum. Results are shown for a range of data rates across a variety of channel types ranging in turbidity from that of a clear ocean to a dirty harbor.

  1. A first-principles study of light non-metallic atom substituted blue phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Minglei [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Tang, Wencheng, E-mail: 101000185@seu.edu.cn [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Ren, Qingqiang [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, Hunan (China); Wang, Sa-ke [Department of Physics, Southeast University, Nanjing 210096, Jiangsu (China); Yu, Jin [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189, Jiangsu (China); Du, Yanhui [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China)

    2015-11-30

    Graphical abstract: - Highlights: • All the impurities are covalently bonded to blue phosphorene (with a single vacancy). • All the substituted systems are semiconductors. • B-substituted system exhibits direct bandgap semiconductor behavior. • The band gaps with spin polarization are found in C and O-substituted systems. • Our works can paves a new route at nanoscale for novel functionalities of optical and spintronics devices. - Abstract: First-principles calculations are implemented to study the geometric, electronic and magnetic properties of light non-metallic atom (B, C, N, O and F) substituted blue phosphorene. All the substituted systems are highly stable. The B-substituted system is a direct bandgap semiconductor with a bandgap size about 1.5 eV. The C, O-substituted systems are promising systems to explore two-dimensional diluted magnetic semiconductors. Magnetism is observed for C and O substitution, while for the other impurities no magnetic moment is detected. Our works paves a new route at nanoscale for novel functionalities of optical and spintronics devices.

  2. Ultraviolet and short wavelength visible light exposure: why ultraviolet protection alone is not adequate.

    Science.gov (United States)

    Reichow, Alan W; Citek, Karl; Edlich, Richard F

    2006-01-01

    The danger of exposure to ultraviolet (UV) radiation in both the natural environment and artificial occupational settings has long been recognized by national and international standards committees and worker safety agencies. There is an increasing body of literature that suggests that protection from UV exposure is not enough. Unprotected exposure to the short wavelengths of the visible spectrum, termed the "blue light hazard", is gaining acceptance as a true risk to long-term visual health. Global standards and experts in the field are now warning that those individuals who spend considerable time outdoors should seek sun filter eyewear with high impact resistant lenses that provide 100% UV filtration, high levels of blue light filtration, and full visual field lens/frame coverage as provided by high wrap eyewear. The Skin Cancer Foundation has endorsed certain sunglasses as "product[s]...effective [as] UV filter[s] for the eyes and surrounding skin". However, such endorsement does not necessarily mean that the eyewear meets all the protective needs for outdoor use. There are several brands that offer products with such protective characteristics. Performance sun eyewear by Nike Vision, available in both corrective and plano (nonprescription) forms, is one such brand incorporating these protective features.

  3. The reduction of retinal autofluorescence caused by light exposure.

    Science.gov (United States)

    Morgan, Jessica I W; Hunter, Jennifer J; Merigan, William H; Williams, David R

    2009-12-01

    A prior study showed that long exposure to 568-nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. The present study shows how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568-nm light over a square subtending 0.5 degrees with energies ranging from 1 to 788 J/cm(2), where power and duration were independently varied. In vivo exposures of 5 J/cm(2) and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures or= 247 J/cm(2)). No significant autofluorescence reduction was observed for exposures of 2 J/cm(2) and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. That reciprocity held is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence.

  4. Design and fabrication of adjustable red-green-blue LED light arrays for plant research

    Directory of Open Access Journals (Sweden)

    Kenitz J Dustin

    2005-08-01

    Full Text Available Abstract Background Although specific light attributes, such as color and fluence rate, influence plant growth and development, researchers generally cannot control the fine spectral conditions of artificial plant-growth environments. Plant growth chambers are typically outfitted with fluorescent and/or incandescent fixtures that provide a general spectrum that is accommodating to the human eye and not necessarily supportive to plant development. Many studies over the last several decades, primarily in Arabidopsis thaliana, have clearly shown that variation in light quantity, quality and photoperiod can be manipulated to affect growth and control developmental transitions. Light emitting diodes (LEDs has been used for decades to test plant responses to narrow-bandwidth light. LEDs are particularly well suited for plant growth chambers, as they have an extraordinary life (about 100,000 hours, require little maintenance, and use negligible energy. These factors render LED-based light strategies particularly appropriate for space-biology as well as terrestrial applications. However, there is a need for a versatile and inexpensive LED array platform where individual wavebands can be specifically tuned to produce a series of light combinations consisting of various quantities and qualities of individual wavelengths. Two plans are presented in this report. Results In this technical report we describe the practical construction of tunable red-green-blue LED arrays to support research in plant growth and development. Two light fixture designs and corresponding circuitry are presented. The first is well suited for a laboratory environment for use in a finite area with small plants, such as Arabidopsis. The second is expandable and appropriate for growth chambers. The application of these arrays to early plant developmental studies has been validated with assays of hypocotyl growth inhibition/promotion and phototropic curvature in Arabidopsis seedlings

  5. Evidence for the Role of Blue Light in the Development of Uveal Melanoma

    Directory of Open Access Journals (Sweden)

    Patrick Logan

    2015-01-01

    Full Text Available Uveal melanoma is the most common malignancy of the adult eye. Although it is a relatively infrequent tumor, clinical prognosis is often poor owing to a high incidence of aggressive metastatic disease, for which there are limited treatment options. Little is known about the etiology of this condition, although several risk factors have been identified. Unlike cutaneous melanoma, however, ultraviolet radiation does not figure prominently among these risk factors. In this review, we focus on an associated form of visible electromagnetic radiation, high-energy short-wave (blue light, a causative agent in various forms of age-related retina damage, as a previously overlooked risk factor in uveal melanoma development and progression. Finally, we discuss the impact of these data on contemporary ocular therapy, particularly the debate surrounding the filtering capabilities of intraocular lenses used to replace dysfunctional crystalline lenses during cataract surgery.

  6. Efficient red, green, blue and white organic light-emitting diodes with same exciplex host

    Science.gov (United States)

    Chang, Chih-Hao; Wu, Szu-Wei; Huang, Chih-Wei; Hsieh, Chung-Tsung; Lin, Sung-En; Chen, Nien-Po; Chang, Hsin-Hua

    2016-03-01

    Recently, exciplex had drawn attention because of its potential for efficient electroluminescence or for use as a host in organic light-emitting diodes (OLEDs). In this study, four kinds of hole transport material/electron transport material combinations were examined to verify the formation of exciplex and the corresponding energy bandgaps. We successfully demonstrated that the combination of tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 3,5,3‧,5‧-tetra(m-pyrid-3-yl)phenyl[1,1‧]biphenyl (BP4mPy) could form a stable exciplex emission with an adequate energy gap. Using exciplex as a host in red, green, and blue phosphorescent OLEDs with an identical trilayer architecture enabled effective energy transfer from exciplex to emitters, achieving corresponding efficiencies of 8.8, 14.1, and 15.8%. A maximum efficiency of 11.3% and stable emission was obtained in white OLEDs.

  7. Advanced Oxidation of Tartrazine and Brilliant Blue with Pulsed Ultraviolet Light Emitting Diodes.

    Science.gov (United States)

    Scott, Robert; Mudimbi, Patrick; Miller, Michael E; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Harper, Willie F

    2017-01-01

      This study investigated the effect of ultraviolet light-emitting diodes (UVLEDs) coupled with hydrogen peroxide as an advanced oxidation process (AOP) for the degradation of two test chemicals. Brilliant Blue FCF consistently exhibited greater degradation than tartrazine, with 83% degradation after 300 minutes at the 100% duty cycle compared with only 17% degradation of tartrazine under the same conditions. These differences are attributable to the structural properties of the compounds. Duty cycle was positively correlated with the first-order rate constants (k) for both chemicals but, interestingly, negatively correlated with the normalized first-order rate constants (k/duty cycle). Synergistic effects of both hydraulic mixing and LED duty cycle were manifested as novel oscillations in the effluent contaminant concentration. Further, LED output and efficiency were dependent upon duty cycle and less efficient over time perhaps due to heating effects on semiconductor performance.

  8. Photocatalytic decolorization of methylene blue over Zn1-xCoxO under visible light irradiation

    International Nuclear Information System (INIS)

    Xiao Qi; Zhang Jiang; Xiao Chong; Tan Xiaoke

    2007-01-01

    Co-doped ZnO photocatalysts were prepared by hydrothermal method. The obtained Co-doped ZnO powders were characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy and photoluminescence (PL) spectra. The prepared Co-doped ZnO photocatalysts showed high photocatalytic activities for methylene blue decolorization at pH 10.5 under visible light irradiation. It was found that there were certain relationships between PL spectra and photocatalytic activity, namely, the stronger the PL intensity, the larger the content of oxygen vacancies and defects, the higher the photocatalytic activity. Therefore, in this study 3.0 mol% was the most suitable content of Co 2+ in ZnO, at which the recombination of photoinduced electrons and holes could be effectively inhibited and thereby the highest photocatalytic activity was formed

  9. Do Wild Great Tits Avoid Exposure to Light at Night?

    Directory of Open Access Journals (Sweden)

    Maaike de Jong

    Full Text Available Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their nighttime light exposure by seeking dark spots within illuminated areas. This uncertainty makes it difficult to attribute effects to a direct effect of light at night, or to indirect effects, e.g., via an effect of light at night on food availability. In this study, we aim to quantify the nocturnal light exposure of wild birds in a previously dark forest-edge habitat, experimentally illuminated with three different colors of street lighting, in comparison to a dark control. During two consecutive breeding seasons, we deployed male great tits (Parus major with a light logger measuring light intensity every five minutes over a 24h period. We found that three males from pairs breeding in brightly illuminated nest boxes close to green and red lamp posts, were not exposed to more artificial light at night than males from pairs breeding further away. This suggests, based on our limited sample size, that these males could have been avoiding light at night by choosing a roosting place with a reduced light intensity. Therefore, effects of light at night previously reported for this species in our experimental set-up might be indirect. In contrast to urban areas where light is omnipresent, bird species in non-urban areas may evade exposure to nocturnal artificial light, thereby avoiding direct consequences of light at night.

  10. Pyridine substituted spirofluorene derivative as an electron transport material for high efficiency in blue organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soon Ok; Yook, Kyoung Soo; Lee, Jun Yeob, E-mail: leej17@dankook.ac.k

    2010-11-01

    The quantum efficiency of blue fluorescent organic light-emitting diodes was enhanced by 20% using a pyridine substituted spirofluorene-benzofluorene derivative as an electron transport material. 2',7'-Di(pyridin-3-yl)spiro[benzofluorene-7,9'-fluorene] (SPBP) was synthesized and it was used as the electron transport material to block the hole leakage from the emitting layer. The improvement of the quantum efficiency and power efficiency of the blue fluorescent organic light-emitting diodes using the SPBP was investigated.

  11. Dimeric Structure of the Blue Light Sensor Protein Photozipper in the Active State.

    Science.gov (United States)

    Ozeki, Kohei; Tsukuno, Hiroyuki; Nagashima, Hiroki; Hisatomi, Osamu; Mino, Hiroyuki

    2018-02-06

    The light oxygen voltage-sensing (LOV) domain plays a crucial role in blue light (BL) sensing in plants and microorganisms. LOV domains are usually associated with the effector domains and regulate the activities of effector domains in a BL-dependent manner. Photozipper (PZ) is monomeric in the dark state. BL induces reversible dimerization of PZ and subsequently increases its affinity for the target DNA sequence. In this study, we report the analyses of PZ by pulsed electron-electron double resonance (PELDOR). The neutral flavin radical was formed by BL illumination in the presence of dithiothreitol in the LOV-C254S (without the bZIP domain) and PZ-C254S mutants, where the cysteine residue responsible for adduct formation was replaced with serine. The magnetic dipole interactions of 3 MHz between the neutral radicals were detected in both LOV-C254S and PZ-C254S, indicating that these mutants are dimeric in the radical state. The PELDOR simulation showed that the distance between the radical pair is close to that estimated from the dimeric crystal structure in the "light state" [Heintz, U., and Schlichting, I. (2016) eLife 5, e11860], suggesting that in the radical state, LOV domains in PZ-C254S form a dimer similar to that of LOV-C254S, which lacks the bZIP domain.

  12. Evidence for Tautomerisation of Glutamine in BLUF Blue Light Receptors by Vibrational Spectroscopy and Computational Chemistry

    Science.gov (United States)

    Domratcheva, Tatiana; Hartmann, Elisabeth; Schlichting, Ilme; Kottke, Tilman

    2016-01-01

    BLUF (blue light sensor using flavin) domains regulate the activity of various enzymatic effector domains in bacteria and euglenids. BLUF features a unique photoactivation through restructuring of the hydrogen-bonding network as opposed to a redox reaction or an isomerization of the chromophore. A conserved glutamine residue close to the flavin chromophore plays a central role in the light response, but the underlying modification is still unclear. We labelled this glutamine with 15N in two representative BLUF domains and performed time-resolved infrared double difference spectroscopy. The assignment of the signals was conducted by extensive quantum chemical calculations on large models with 187 atoms reproducing the UV-vis and infrared signatures of BLUF photoactivation. In the dark state, the comparatively low frequency of 1,667 cm−1 is assigned to the glutamine C=O accepting a hydrogen bond from tyrosine. In the light state, the signature of a tautomerised glutamine was extracted with the C=N stretch at ~1,691 cm−1 exhibiting the characteristic strong downshift by 15N labelling. Moreover, an indirect isotope effect on the flavin C4=O stretch was found. We conclude that photoactivation of the BLUF receptor does not only involve a rearrangement of hydrogen bonds but includes a change in covalent bonds of the protein. PMID:26947391

  13. Comparative Study of Lettuce and Radish Grown Under Red and Blue Light-Emitting Diodes (LEDs) and White Fluorescent Lamps

    Science.gov (United States)

    Mickens, Matthew A.

    2012-01-01

    Growing vegetable crops in space will be an essential part of sustaining astronauts during long-term missions. To drive photosynthesis, red and blue light-emitting diodes (LEDs) have attracted attention because of their efficiency, longevity, small size, and safety. In efforts to optimize crop production, there have also been recent interests in analyzing the subtle effects of green light on plant growth, and to determine if it serves as a source of growth enhancement or suppression. A comparative study was performed on two short cycle crops of lettuce (Outredgeous) and radish (Cherry Bomb) grown under two light treatments. The first treatment being red and blue LEDs, and the second treatment consisting of white fluorescent lamps which contain a portion of green light. In addition to comparing biomass production, physiological characterizations were conducted on how the light treatments influence morphology, water use, chlorophyll content, and the production of A TP within plant tissues.

  14. Damage to the macula associated with LED-derived blue laser exposure: A case report.

    Science.gov (United States)

    Liang, Lingling; Cui, Zhihua; Lu, Chengwei; Hao, Qian; Zheng, Yajuan

    2017-04-24

    Light emitting diodes laser is emerging as an important source of light replacing conventional lights. It is widely used for illumination in the bar where young people love to go. But not everyone knows about the light damage to the eye especially to the macula. In this article, we report the case of a macular damage induced by LED-derived blue laser in a bar, studied with optical coherence tomography (OCT) to evaluate the retinal lesion and multifocal electroretinography (mfERG) to evaluate functional damage. Four days after the photo injury to the right eye, the visual acuity was 0.5. Funduscopy revealed a round red lesion in the macula of the right eye. Fluorescein angiography (FA) revealed no leakage. OCT revealed a deficiency in the center of the fovea. MfERG revealed a reduction of the peak value in the right eye compared to the left eye. One month later, although the vision was 1.0 in the right eye, OCT revealed a hyporeflectivity of the ellipsoid zone. MfERG still showed a reduction of the peak value in the right eye compared to the left eye. We believe that general knowledge about laser injuries to the eye should be realized widely. We also think in cases of macular laser damage, the recovery of vision can not demonstrate the recovery of the function of photoreceptors.

  15. Dynamic Blue Light-Inducible T7 RNA Polymerases (Opto-T7RNAPs) for Precise Spatiotemporal Gene Expression Control.

    Science.gov (United States)

    Baumschlager, Armin; Aoki, Stephanie K; Khammash, Mustafa

    2017-11-17

    Light has emerged as a control input for biological systems due to its precise spatiotemporal resolution. The limited toolset for light control in bacteria motivated us to develop a light-inducible transcription system that is independent from cellular regulation through the use of an orthogonal RNA polymerase. Here, we present our engineered blue light-responsive T7 RNA polymerases (Opto-T7RNAPs) that show properties such as low leakiness of gene expression in the dark state, high expression strength when induced with blue light, and an inducible range of more than 300-fold. Following optimization of the system to reduce expression variability, we created a variant that returns to the inactive dark state within minutes once the blue light is turned off. This allows for precise dynamic control of gene expression, which is a key aspect for most applications using optogenetic regulation. The regulators, which only require blue light from ordinary light-emitting diodes for induction, were developed and tested in the bacterium Escherichia coli, which is a crucial cell factory for biotechnology due to its fast and inexpensive cultivation and well understood physiology and genetics. Opto-T7RNAP, with minor alterations, should be extendable to other bacterial species as well as eukaryotes such as mammalian cells and yeast in which the T7 RNA polymerase and the light-inducible Vivid regulator have been shown to be functional. We anticipate that our approach will expand the applicability of using light as an inducer for gene expression independent from cellular regulation and allow for a more reliable dynamic control of synthetic and natural gene networks.

  16. Anatomical features of pepper plants (Capsicum annuum L.) grown under red light-emitting diodes supplemented with blue or far-red light

    Science.gov (United States)

    Schuerger, A. C.; Brown, C. S.; Stryjewski, E. C.

    1997-01-01

    Pepper plants (Capsicum annuum L. cv., Hungarian Wax) were grown under metal halide (MH) lamps or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on plant anatomy of leaves and stems. One LED (660) array supplied 90% red light at 660 nm (25nm band-width at half-peak height) and 1% far-red light between 700-800nm. A second LED (660/735) array supplied 83% red light at 660nm and 17% far-red light at 735nm (25nm band-width at half-peak height). A third LED (660/blue) array supplied 98% red light at 660nm, 1% blue light between 350-550nm, and 1% far-red light between 700-800nm. Control plants were grown under broad spectrum metal halide lamps. Plants were gron at a mean photon flux (300-800nm) of 330 micromol m-2 s-1 under a 12 h day-night photoperiod. Significant anatomical changes in stem and leaf morphologies were observed in plants grown under the LED arrays compared to plants grown under the broad-spectrum MH lamp. Cross-sectional areas of pepper stems, thickness of secondary xylem, numbers of intraxylary phloem bundles in the periphery of stem pith tissues, leaf thickness, numbers of choloplasts per palisade mesophyll cell, and thickness of palisade and spongy mesophyll tissues were greatest in peppers grown under MH lamps, intermediate in plants grown under the 660/blue LED array, and lowest in peppers grown under the 660 or 660/735 LED arrays. Most anatomical features of pepper stems and leaves were similar among plants grown under 660 or 660/735 LED arrays. The effects of spectral quality on anatomical changes in stem and leaf tissues of peppers generally correlate to the amount of blue light present in the primary light source.

  17. Blue light irradiation triggers the antimicrobial potential of ZnO nanoparticles on drug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Yang, Ming-Yeh; Chang, Kai-Chih; Chen, Liang-Yu; Wang, Po-Ching; Chou, Chih-Chiang; Wu, Zhong-Bin; Hu, Anren

    2018-03-01

    Photodynamic inactivation (PDI) is a non-invasive and safe therapeutic method for microbial infections. Bacterial antibiotic resistance is caused by antibiotics abuse. Drug-resistant Acinetobacter spp. is a serious problem in hospitals around the world. These pathogens from nosocomial infections have high mortality rates in frailer people, and Acinetobacter spp. is commonly found in immunocompromised patients. Visible light is safer than ultraviolet light (UV) for PDI of nosocomial pathogens with mammalian cells. Zinc oxide nanoparticles (ZnO-NPs) were used in this study as an antimicrobial agent and a photosensitizer. ZnO is recognized as safe and has extensive usage in food additives, medical and cosmetic products. In this study, we used 0.125 mg/ml ZnO-NPs combined with 10.8 J/cm 2 blue light (BL) on Acinetobacter baumannii (A. baumannii) that could significantly reduce microbial survival. However, individual exposure to ZnO-NPs does not affect the viability of A. baumannii. BL irradiation could trigger the antimicrobial ability of ZnO nanoparticles on A. baumannii. The mechanism of photocatalytic ZnO-NPs treatment for sterilization occurs through bacterial membrane disruptions. Otherwise, the photocatalytic ZnO-NPs treatment showed high microbial eradication in nosocomial pathogens, including colistin-resistant and imipenem-resistant A. baumannii and Klebsiella pneumoniae. Based on our results, the photocatalytic ZnO-NPs treatment could support hygiene control and clinical therapies without antibiotics to nosocomial bacterial infections. Copyright © 2018. Published by Elsevier B.V.

  18. From Plant Infectivity to Growth Patterns: The Role of Blue-Light Sensing in the Prokaryotic World

    Directory of Open Access Journals (Sweden)

    Aba Losi

    2014-01-01

    Full Text Available Flavin-based photoreceptor proteins of the LOV (Light, Oxygen, and Voltage and BLUF (Blue Light sensing Using Flavins superfamilies are ubiquitous among the three life domains and are essential blue-light sensing systems, not only in plants and algae, but also in prokaryotes. Here we review their biological roles in the prokaryotic world and their evolution pathways. An unexpected large number of bacterial species possess flavin-based photosensors, amongst which are important human and plant pathogens. Still, few cases are reported where the activity of blue-light sensors could be correlated to infectivity and/or has been shown to be involved in the activation of specific genes, resulting in selective growth patterns. Metagenomics and bio-informatic analysis have only recently been initiated, but signatures are beginning to emerge that allow definition of a bona fide LOV or BLUF domain, aiming at better selection criteria for novel blue-light sensors. We also present here, for the first time, the phylogenetic tree for archaeal LOV domains that have reached a statistically significant number but have not at all been investigated thus far.

  19. effect of continous light and darkness exposures on the pituitary

    African Journals Online (AJOL)

    Dr Olaleye

    The effects of constant light and dark exposure of pubertal male rats on the pituitary-gonadal axis and thyroid activity were studied. ... In the rats exposed to continuous light, the weight of the thyroid gland increased significantly (P<0.02) and the serum level of T4 also ... 3minutes) per day when food in the cages was being.

  20. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...

  1. Thermally Activated Delayed Fluorescence Emitters for Deep Blue Organic Light Emitting Diodes: A Review of Recent Advances

    Directory of Open Access Journals (Sweden)

    Thanh-Tuân Bui

    2018-03-01

    Full Text Available Organic light-emitting diodes offer attractive perspectives for the next generation display and lighting technologies. The potential is huge and the list of potential applications is almost endless. So far, blue emitters still suffer from noticeably inferior electroluminescence performances in terms of efficiency, lifespan, color quality, and charge injection/transport when compared to that of the other colors. Emitting materials matching the NTSC standard blue of coordinates (0.14, 0.08 are extremely rare and still constitutes the focus of numerous academic and industrial researches. In this context, we review herein the recent developments on highly emissive deep-blue thermally activated delayed fluorescence emitters that constitute the third-generation electroluminescent materials.

  2. Controlled light emission from white organic light-emitting devices with a single blue-emitting host and multiple fluorescent dopants

    International Nuclear Information System (INIS)

    Chin, Byung Doo; Kim, Jai Kyeong; Park, O Ok

    2007-01-01

    In this work, we fabricated white organic light-emitting devices (WOLEDs) containing a layered light-emitting region composed of a single blue-emitting host and different fluorescent dopant materials. The effects of varying the dye-doping ratio and emitting layer thickness on the efficiency, lifetime, spectral voltage-dependence and white balance were investigated for devices with a blue/orange stacked layer structure. Addition of a blue host layer doped with a green-emitting dopant, to give a blue/green/orange emitter, resulted in a broadband white spectrum without the need for a charge-blocking interlayer. The composition of blue, green and orange dopants in the host and the thickness of each emitting layer were optimized, resulting in a device efficiency of 9-11 cd A -1 even at a high brightness of 10 000 cd m -2 (achieved at a bias voltage of less than 9 V) with an emission spectrum suitable for lighting applications

  3. Red photoluminescent property and modification of WO3:Eu3+ inverse opal for blue light converted LEDs

    Science.gov (United States)

    Ruan, Jiufeng; Yang, Zhengwen; Huang, Anjun; Chai, Zhuangzhuang; Qiu, Jianbei; Song, Zhiguo

    2018-01-01

    Blue light converted light-emitting diodes is of great significance as a candidate for next generation lighting. In this work, the WO3:Eu3+ inverse opal photonic crystals were prepared and their luminescence properties were studied. The results demonstrated that the main excitation peak of WO3:Eu3+ inverse opals were located at 465 nm. The red luminescence peak at the 613 nm was observed in the WO3:Eu3+ inverse opal upon 465 nm excitation, exhibiting better red color purity. The influence of photonic band gap on the photoluminescence of WO3:Eu3+ inverse opal was obtained. When the red luminescence peak is in the regions of the photonic band gap and the edge of the band-gap, the red luminescence suppression and enhancement was observed respectively. The WO3:Eu3+ inverse opals may be a promising candidate for the blue light converted LEDs.

  4. Antimicrobial blue light: a drug-free approach for inactivating pathogenic microbes

    Science.gov (United States)

    Wang, Ying; Dai, Tianhong

    2018-02-01

    Due to the growing global threat of antibiotic resistance, there is a critical need for the development of alternative therapeutics for infectious diseases. Antimicrobial blue light (aBL), as an innovative non-antibiotic approach, has attracted increasing attention. This paper discussed the basic concepts of aBL and recent findings in the studies of aBL. It is commonly hypothesized that the antimicrobial property of aBL is attributed to the presence of endogenous photosensitizing chromophores in microbial cells, which produce cytotoxic reactive oxygen species upon light irradiation. A wide range of important microbes are found to be susceptible to aBL inactivation. Studies have also shown there exist therapeutic windows where microbes are selectively inactivated by aBL while host cells are preserved. The combination of aBL with some other agents result in synergistically improved antimicrobial efficacy. Future efforts should be exerted on the standardization of study design for evaluating aBL efficacy, further elucidation of the mechanism of action, optimization of the technical parameters, and translation of this technique to clinic.

  5. Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chih-Hao, E-mail: chc@saturn.yzu.edu.tw [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh [Department of Photonics Engineering, Yuan Ze University, Chung-Li, Taiwan 32003 (China); Chang, Hsin-Hua, E-mail: hhua3@mail.vnu.edu.tw [Department of Electro-Optical Engineering, Vanung University, Chung-Li, Taiwan 32061 (China)

    2011-09-01

    Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m{sup 2}) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

  6. AZO/Ag/AZO anode for resonant cavity red, blue, and yellow organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Gentle, A. R., E-mail: angus.gentle@uts.edu.au; Smith, G. B. [School of Mathematical and Physical Sciences and Institute of Nanoscale Technology, University of Technology Sydney, P.O. Box 123, Broadway, New South Wales 2007 (Australia); Yambem, S. D.; Burn, P. L.; Meredith, P. [Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072 (Australia)

    2016-06-28

    Indium tin oxide (ITO) is the transparent electrode of choice for organic light-emitting diodes (OLEDs). Replacing ITO for cost and performance reasons is a major drive across optoelectronics. In this work, we show that changing the transparent electrode on red, blue, and yellow OLEDs from ITO to a multilayer buffered aluminium zinc oxide/silver/aluminium zinc oxide (AZO/Ag/AZO) substantially enhances total output intensity, with better control of colour, its constancy, and intensity over the full exit hemisphere. The thin Ag containing layer induces a resonant cavity optical response of the complete device. This is tuned to the emission spectra of the emissive material while minimizing internally trapped light. A complete set of spectral intensity data is presented across the full exit hemisphere for each electrode type and each OLED colour. Emission zone modelling of output spectra at a wide range of exit angles to the normal was in excellent agreement with the experimental data and hence could, in principle, be used to check and adjust production settings. These multilayer transparent electrodes show significant potential for both eliminating indium from OLEDs and spectrally shaping the emission.

  7. Highly efficient phosphorescent blue and white organic light-emitting devices with simplified architectures

    International Nuclear Information System (INIS)

    Chang, Chih-Hao; Ding, Yong-Shung; Hsieh, Po-Wei; Chang, Chien-Ping; Lin, Wei-Chieh; Chang, Hsin-Hua

    2011-01-01

    Blue phosphorescent organic light-emitting devices (PhOLEDs) with quantum efficiency close to the theoretical maximum were achieved by utilizing a double-layer architecture. Two wide-triplet-gap materials, 1,3-bis(9-carbazolyl)benzene and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, were employed in the emitting and electron-transport layers respectively. The opposite carrier-transport characteristics of these two materials were leveraged to define the exciton formation zone and thus increase the probability of recombination. The efficiency at practical luminance (100 cd/m 2 ) was as high as 20.8%, 47.7 cd/A and 31.2 lm/W, respectively. Furthermore, based on the design concept of this simplified architecture, efficient warmish-white PhOLEDs were developed. Such two-component white organic light-emitting devices exhibited rather stable colors over a wide brightness range and yielded electroluminescence efficiencies of 15.3%, 33.3 cd/A, and 22.7 lm/W in the forward directions.

  8. Ultraviolet Laser SQUID Microscope for GaN Blue Light Emitting Diode Testing

    International Nuclear Information System (INIS)

    Daibo, M; Kamiwano, D; Kurosawa, T; Yoshizawa, M; Tayama, N

    2006-01-01

    We carried out non-contacting measurements of photocurrent distributions in GaN blue light emitting diode (LED) chips using our newly developed ultraviolet (UV) laser SQUID microscope. The UV light generates the photocurrent, and then the photocurrent induces small magnetic fields around the chip. An off-axis arranged HTS-SQUID magnetometer is employed to detect a vector magnetic field whose typical amplitude is several hundred femto-tesla. Generally, it is difficult to obtain Ohmic contacts for p-type GaN because of the low hole concentration in the p-type epitaxial layer and the lack of any available metal with a higher work function compared with the p-type GaN. Therefore, a traditional probecontacted electrical test is difficult to conduct for wide band gap semiconductors without an adequately annealed electrode. Using the UV-laser SQUID microscope, the photocurrent can be measured without any electrical contact. We show the photocurrent vector map which was reconstructed from measured magnetic fields data. We also demonstrate how we found the position of a defect of the electrical short circuits in the LED chip

  9. Bright light in elderly subjects with nonseasonal major depressive disorder: a double blind randomised clinical trial using early morning bright blue light comparing dim red light treatment

    Directory of Open Access Journals (Sweden)

    van Someren Eus JW

    2008-07-01

    Full Text Available Abstract Background Depression frequently occurs in the elderly. Its cause is largely unknown, but several studies point to disturbances of biological rhythmicity. In both normal aging, and depression, the functioning of the suprachiasmatic nucleus (SCN is impaired, as evidenced by an increased prevalence of day-night rhythm perturbations, such as sleeping disorders. Moreover, the inhibitory SCN neurons on the hypothalamus-pituitary adrenocortical axis (HPA-axis have decreased activity and HPA-activity is enhanced, when compared to non-depressed elderly. Using bright light therapy (BLT the SCN can be stimulated. In addition, the beneficial effects of BLT on seasonal depression are well accepted. BLT is a potentially safe, nonexpensive and well accepted treatment option. But the current literature on BLT for depression is inconclusive. Methods/Design This study aims to show whether BLT can reduce non-seasonal major depression in elderly patients. Randomized double blind placebo controlled trial in 126 subjects of 60 years and older with a diagnosis of major depressive disorder (MDD, DSM-IV/SCID-I. Subjects are recruited through referrals of psychiatric outpatient clinics and from case finding from databases of general practitioners and old-people homes in the Amsterdam region. After inclusion subjects are randomly allocated to the active (bright blue light vs. placebo (dim red light condition using two Philips Bright Light Energy boxes type HF 3304 per subject, from which the light bulbs have been covered with bright blue- or dim red light- permitting filters. Patients will be stratified by use of antidepressants. Prior to treatment a one-week period without light treatment will be used. At three time points several endocrinological, psychophysiological, psychometrically, neuropsychological measures are performed: just before the start of light therapy, after completion of three weeks therapy period, and three weeks thereafter. Discussion If BLT

  10. The Impact of Blue Light Cystoscopy with Hexaminolevulinate (HAL) on Progression of Bladder Cancer - A New Analysis

    NARCIS (Netherlands)

    Kamat, A.M.; Cookson, M.; Witjes, J.A.; Stenzl, A.; Grossman, H.B.

    2016-01-01

    Background: The International Bladder Cancer Group (IBCG) recently proposed a new definition of disease progression in non-muscle invasive bladder cancer (NMIBC), including change in T-stage, change to T2 or higher or change from low to high grade. Objective: To establish whether blue light

  11. Evaluation of 405nm CW visible blue light as a means of inactivating Tulane Virus on Blueberries

    Science.gov (United States)

    Introduction: Visible blue light (405nm) is effective against bacteria but its potential as a nonthermal intervention for viruses on foods, such as berries that are prone to norovirus contamination has not been evaluated. Tulane virus (TV) is now a common human norovirus surrogate that can be propa...

  12. Influence of blue and red light illumination on the holographic storage in an azopolyester–PMMA blend

    DEFF Research Database (Denmark)

    Berges, C.; Díez, I.; Javakhishvili, Irakli

    2014-01-01

    . The dependence of holographic storage on the recording condition has been studied. No stable gratings can be recorded in thermally quenched films. The presence of cis isomers that can be induced by blue light irradiation seems to be necessary to store stable gratings. The cis isomer content and consequently...

  13. Effect of arylamine hole-transport units on the performance of blue polyspirobifulorene light-emitting diodes

    NARCIS (Netherlands)

    Abbaszadeh, D.; Nicolai, H.T.; Crəciun, N.I.; Blom, P.W.M.

    2014-01-01

    The operation of blue light-emitting diodes based on polyspirobifluorene with a varying number of N,N,N′,N′ tetraaryldiamino biphenyl (TAD) hole-transport units (HTUs) is investigated. Assuming that the electron transport is not affected by the incorporation of TAD units, model calculations predict

  14. HOT DUST OBSCURED GALAXIES WITH EXCESS BLUE LIGHT: DUAL AGN OR SINGLE AGN UNDER EXTREME CONDITIONS?

    Energy Technology Data Exchange (ETDEWEB)

    Assef, R. J.; Diaz-Santos, T. [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Walton, D. J.; Brightman, M. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Stern, D.; Eisenhardt, P. R. M.; Tsai, C.-W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-236, Pasadena, CA 91109 (United States); Alexander, D. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Bauer, F. [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Blain, A. W. [Physics and Astronomy, University of Leicester, 1 University Road, Leicester LE1 7RH (United Kingdom); Finkelstein, S. L. [The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Hickox, R. C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Wu, J. W., E-mail: roberto.assef@mail.udp.cl [UCLA Astronomy, P.O. Box 951547, Los Angeles, CA 90095-1547 (United States)

    2016-03-10

    Hot dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous infrared galaxies identified by the Wide-field Infrared Survey Explorer (WISE) mission from their very red mid-IR colors, and characterized by hot dust temperatures (T > 60 K). Several studies have shown clear evidence that the IR emission in these objects is powered by a highly dust-obscured active galactic nucleus (AGN) that shows close to Compton-thick absorption at X-ray wavelengths. Thanks to the high AGN obscuration, the host galaxy is easily observable, and has UV/optical colors usually consistent with those of a normal galaxy. Here we discuss a sub-population of eight Hot DOGs that show enhanced rest-frame UV/optical emission. We discuss three scenarios that might explain the excess UV emission: (i) unobscured light leaked from the AGN by reflection over the dust or by partial coverage of the accretion disk; (ii) a second unobscured AGN in the system; or (iii) a luminous young starburst. X-ray observations can help discriminate between these scenarios. We study in detail the blue excess Hot DOG WISE J020446.13–050640.8, which was serendipitously observed by Chandra/ACIS-I for 174.5 ks. The X-ray spectrum is consistent with a single, hyper-luminous, highly absorbed AGN, and is strongly inconsistent with the presence of a secondary unobscured AGN. Based on this, we argue that the excess blue emission in this object is most likely either due to reflection or a co-eval starburst. We favor the reflection scenario as the unobscured star formation rate needed to power the UV/optical emission would be ≳1000 M{sub ⊙} yr{sup −1}. Deep polarimetry observations could confirm the reflection hypothesis.

  15. HOT DUST OBSCURED GALAXIES WITH EXCESS BLUE LIGHT: DUAL AGN OR SINGLE AGN UNDER EXTREME CONDITIONS?

    International Nuclear Information System (INIS)

    Assef, R. J.; Diaz-Santos, T.; Walton, D. J.; Brightman, M.; Stern, D.; Eisenhardt, P. R. M.; Tsai, C.-W.; Alexander, D.; Bauer, F.; Blain, A. W.; Finkelstein, S. L.; Hickox, R. C.; Wu, J. W.

    2016-01-01

    Hot dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous infrared galaxies identified by the Wide-field Infrared Survey Explorer (WISE) mission from their very red mid-IR colors, and characterized by hot dust temperatures (T > 60 K). Several studies have shown clear evidence that the IR emission in these objects is powered by a highly dust-obscured active galactic nucleus (AGN) that shows close to Compton-thick absorption at X-ray wavelengths. Thanks to the high AGN obscuration, the host galaxy is easily observable, and has UV/optical colors usually consistent with those of a normal galaxy. Here we discuss a sub-population of eight Hot DOGs that show enhanced rest-frame UV/optical emission. We discuss three scenarios that might explain the excess UV emission: (i) unobscured light leaked from the AGN by reflection over the dust or by partial coverage of the accretion disk; (ii) a second unobscured AGN in the system; or (iii) a luminous young starburst. X-ray observations can help discriminate between these scenarios. We study in detail the blue excess Hot DOG WISE J020446.13–050640.8, which was serendipitously observed by Chandra/ACIS-I for 174.5 ks. The X-ray spectrum is consistent with a single, hyper-luminous, highly absorbed AGN, and is strongly inconsistent with the presence of a secondary unobscured AGN. Based on this, we argue that the excess blue emission in this object is most likely either due to reflection or a co-eval starburst. We favor the reflection scenario as the unobscured star formation rate needed to power the UV/optical emission would be ≳1000 M ⊙ yr −1 . Deep polarimetry observations could confirm the reflection hypothesis

  16. Color Degradation of Textiles with Natural Dyes and of Blue Scale Standards Exposed to White LED Lamps:Evaluation of White LED Lamps for Effectiveness as Museum Lighting

    Science.gov (United States)

    Ishii, Mie; Moriyama, Takayoshi; Toda, Masahiro; Kohmoto, Kohtaro; Saito, Masako

    White light-emitting diodes (LED) are well suited for museum lighting because they emit neither UV nor IR radiation, which damage artifacts. The color degradation of natural dyes and blue scale standards (JIS L 0841) by white LED lamps are examined, and the performance of white LED lamps for museum lighting is evaluated. Blue scale standard grades 1-6 and silk fabrics dyed with 22 types of natural dyes classified as mid to highly responsive in a CIE technical report (CIE157:2004) were exposed to five types of white LED lamps using different luminescence methods and color temperatures. Color changes were measured at each 15000 lx·hr (500 lx at fabric surface × 300 hr) interval ten times. The accumulated exposure totaled 150000 lx·hr. The data on conventional white LED lamps and previously reported white fluorescent (W) and museum fluorescent (NU) lamps was evaluated. All the white LED lamps showed lower fading rates compared with a W lamp on a blue scale grade 1. The fading rate of natural dyes in total was the same between an NU lamp (3000 K) and a white LED lamp (2869 K). However, yellow natural dyes showed higher fading rates with the white LED lamp. This tendency is due to the high power characteristic of the LED lamp around 400-500 nm, which possibly contributes to the photo-fading action on the dyes. The most faded yellow dyes were Ukon (Curcuma longa L.) and Kihada (Phellodendron amurense Rupr.), and these are frequently used in historic artifacts such as kimono, wood-block prints, and scrolls. From a conservation point of view, we need to continue research on white LED lamps for use in museum lighting.

  17. High-Brightness Blue Light-Emitting Diodes Enabled by a Directly Grown Graphene Buffer Layer.

    Science.gov (United States)

    Chen, Zhaolong; Zhang, Xiang; Dou, Zhipeng; Wei, Tongbo; Liu, Zhiqiang; Qi, Yue; Ci, Haina; Wang, Yunyu; Li, Yang; Chang, Hongliang; Yan, Jianchang; Yang, Shenyuan; Zhang, Yanfeng; Wang, Junxi; Gao, Peng; Li, Jinmin; Liu, Zhongfan

    2018-06-08

    Single-crystalline GaN-based light-emitting diodes (LEDs) with high efficiency and long lifetime are the most promising solid-state lighting source compared with conventional incandescent and fluorescent lamps. However, the lattice and thermal mismatch between GaN and sapphire substrate always induces high stress and high density of dislocations and thus degrades the performance of LEDs. Here, the growth of high-quality GaN with low stress and a low density of dislocations on graphene (Gr) buffered sapphire substrate is reported for high-brightness blue LEDs. Gr films are directly grown on sapphire substrate to avoid the tedious transfer process and GaN is grown by metal-organic chemical vapor deposition (MOCVD). The introduced Gr buffer layer greatly releases biaxial stress and reduces the density of dislocations in GaN film and In x Ga 1- x N/GaN multiple quantum well structures. The as-fabricated LED devices therefore deliver much higher light output power compared to that on a bare sapphire substrate, which even outperforms the mature process derived counterpart. The GaN growth on Gr buffered sapphire only requires one-step growth, which largely shortens the MOCVD growth time. This facile strategy may pave a new way for applications of Gr films and bring several disruptive technologies for epitaxial growth of GaN film and its applications in high-brightness LEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Plasma temperature during methylene blue/light treatment influences virus inactivation capacity and product quality.

    Science.gov (United States)

    Gravemann, U; Handke, W; Sumian, C; Alvarez, I; Reichenberg, S; Müller, T H; Seltsam, A

    2018-02-27

    Photodynamic treatment using methylene blue (MB) and visible light is in routine use for pathogen inactivation of human plasma in different countries. Ambient and product temperature conditions for human plasma during production may vary between production sites. The influence of different temperature conditions on virus inactivation capacity and plasma quality of the THERAFLEX MB-Plasma procedure was investigated in this study. Plasma units equilibrated to 5 ± 2°C, room temperature (22 ± 2°C) or 30 ± 2°C were treated with MB/light and comparatively assessed for the inactivation capacity for three different viruses, concentrations of MB and its photoproducts, activity of various plasma coagulation factors and clotting time. Reduced solubility of the MB pill was observed at 5 ± 2°C. Photocatalytic degradation of MB increased with increasing temperature, and the greatest formation of photoproducts (mainly azure B) occurred at 30 ± 2°C. Inactivation of suid herpesvirus, bovine viral diarrhoea virus and vesicular stomatitis virus was significantly lower at 5 ± 2°C than at higher temperatures. MB/light treatment affected clotting times and the activity of almost all investigated plasma proteins. Factor VIII (-17·7 ± 8·3%, 22 ± 2°C) and fibrinogen (-14·4 ± 16·4%, 22 ± 2°C) showed the highest decreases in activity. Increasing plasma temperatures resulted in greater changes in clotting time and higher losses of plasma coagulation factor activity. Temperature conditions for THERAFLEX MB-Plasma treatment must be carefully controlled to assure uniform quality of pathogen-reduced plasma in routine production. Inactivation of cooled plasma is not recommended. © 2018 International Society of Blood Transfusion.

  19. Gigabit-per-second white light-based visible light communication using near-ultraviolet laser diode and red-, green-, and blue-emitting phosphors

    KAUST Repository

    Lee, Changmin; Shen, Chao; Cozzan, Clayton; Farrell, Robert M.; Speck, James S.; Nakamura, Shuji; Ooi, Boon S.; DenBaars, Steven P.

    2017-01-01

    Data communication based on white light generated using a near-ultraviolet (NUV) laser diode (LD) pumping red-, green-, and blue-emitting (RGB) phosphors was demonstrated for the first time. A III-nitride laser diode (LD) on a semipolar (2021

  20. A sensitive resveratrol assay with a simple probe methylene blue by resonance light scattering technique

    Science.gov (United States)

    Xiang, Haiyan; Dai, Kaijin; Luo, Qizhi; Duan, Wenjun; Xie, Yang

    2011-01-01

    A novel resonance light scattering (RLS) method was developed for the determination of resveratrol based on the interaction between resveratrol and methylene blue (MB). It was found that at pH 8.69, the weak RLS intensity of MB was remarkably enhanced by the addition of trace amount of resveratrol with the maximum peak located at 385.0 nm. Under the optimum conditions, a good linear relationship between the enhanced RLS intensities and the concentrations of resveratrol was obtained over the range of 2.0-14.0 μg ml -1 with the detection limit (3 σ) of 0.63 μg ml -1. The results of the analysis of resveratrol in synthetic samples and human urine are satisfactory, which showed it may provide a more sensitive, convenient, rapid and reproducible method for the detection of resveratrol, especially in biological and pharmaceutical field. In this work, the characteristics of RLS, absorption and fluorescence spectra of the resveratrol-MB system, the influencing factors and the optimum conditions of the reaction were investigated.

  1. Blue emitting 1,8-naphthalimides with electron transport properties for organic light emitting diode applications

    Science.gov (United States)

    Ulla, Hidayath; Kiran, M. Raveendra; Garudachari, B.; Ahipa, T. N.; Tarafder, Kartick; Adhikari, Airody Vasudeva; Umesh, G.; Satyanarayan, M. N.

    2017-09-01

    In this article, the synthesis, characterization and use of two novel naphthalimides as electron-transporting emitter materials for organic light emitting diode (OLED) applications are reported. The molecules were obtained by substituting electron donating chloro-phenoxy group at the C-4 position. A detailed optical, thermal, electrochemical and related properties were systematically studied. Furthermore, theoretical calculations (DFT) were performed to get a better understanding of the electronic structures. The synthesized molecules were used as electron transporters and emitters in OLEDs with three different device configurations. The devices with the molecules showed blue emission with efficiencies of 1.89 cdA-1, 0.98 lmW-1, 0.71% at 100 cdm-2. The phosphorescent devices with naphthalimides as electron transport materials displayed better performance in comparison to the device without any electron transporting material and were analogous with the device using standard electron transporting material, Alq3. The results demonstrate that the naphthalimides could play a significant part in the progress of OLEDs.

  2. Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO2

    Directory of Open Access Journals (Sweden)

    Zatil Amali Che Ramli

    2014-01-01

    Full Text Available This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC, TiO2/carbon (C, and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, thermogravimetric analysis (TG-DTA, Brunauer-Emmet-Teller (BET, and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m2 g−1. The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

  3. Photoinhibition of stem elongation by blue and red light: effects on hydraulic and cell wall properties

    Science.gov (United States)

    Kigel, J.; Cosgrove, D. J.

    1991-01-01

    The underlying mechanism of photoinhibition of stem elongation by blue (BL) and red light (RL) was studied in etiolated seedlings of pea (Pisum sativum L. cv Alaska). Brief BL irradiations resulted in fast transient inhibition of elongation, while a delayed (lag approximately 60 minutes) but prolonged inhibition was observed after brief RL. Possible changes in the hydraulic and wall properties of the growing cells during photoinhibition were examined. Cell sap osmotic pressure was unaffected by BL and RL, but both irradiations increased turgor pressure by approximately 0.05 megapascal (pressure-probe technique). Cell wall yielding was analyzed by in vivo stress relaxation (pressure-block technique). BL and RL reduced the initial rate of relaxation by 38 and 54%, while the final amount of relaxation was decreased by 48 and 10%, respectively. These results indicate that RL inhibits elongation mainly by lowering the wall yield coefficient, while most of the inhibitory effect of BL was due to an increase of the yield threshold. Mechanical extensibility of cell walls (Instron technique) was decreased by BL and RL, mainly due to a reduction in the plastic component of extensibility. Thus, photoinhibitions of elongation by both BL and RL are achieved through changes in cell wall properties, and are not due to effects on the hydraulic properties of the cell.

  4. Mechanism of blue-light-induced plasma-membrane depolarization in etiolated cucumber hypocotyls

    Science.gov (United States)

    Spalding, E. P.; Cosgrove, D. J.

    1992-01-01

    A large, transient depolarization of the plasma membrane precedes the rapid blue-light (BL)-induced growth suppression in etiolated seedlings of Cucumis sativus L. The mechanism of this voltage transient was investigated by applying inhibitors of ion channels and the plasma-membrane H(+)-ATPase, by manipulating extracellular ion concentrations, and by measuring cell input resistance and ATP levels. The depolarizing phase was not affected by Ca(2+)-channel blockers (verapamil, La3+) or by reducing extracellular free Ca2+ by treatment with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). However, these treatments did reduce the rate of repolarization, indicating an inward movement of Ca2+ is involved. No effects of the K(+)-channel blocker tetraethylammonium (TEA+) were detected. Vanadate and KCN, used to inhibit the H(+)-ATPase, reduced or completely inhibited the BL-induced depolarization. Levels of ATP increased by 11-26% after 1-2 min of BL. Input resistance of trichrome cells, measured with double-barreled microelectrodes, remained constant during the onset of the depolarization but decreased as the membrane voltage became more positive than -90 mV. The results indicate that the depolarization mechanism initially involves inactivation of the H(+)-ATPase with subsequent transient activation of one or more types of ion channels.

  5. Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses.

    Science.gov (United States)

    Nagai, Hiroyuki; Hirano, Yoshio; Yasukawa, Tsutomu; Morita, Hiroshi; Nozaki, Miho; Wolf-Schnurrbusch, Ute; Wolf, Sebastian; Ogura, Yuichiro

    2015-09-01

    To observe changes in fundus autofluorescence 2 years after implantation of blue light-filtering (yellow-tinted) and ultraviolet light-filtering (colorless) intraocular lenses (IOLs). Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, and the Department of Ophthalmology, University of Bern, Bern, Switzerland. Prospective comparative observational study. Patients were enrolled who had cataract surgery with implantation of a yellow-tinted or colorless IOL and for whom images were obtained on which the fundus autofluorescence was measurable using the Heidelberg Retina Angiogram 2 postoperatively. The fundus autofluorescence in the images was classified into 8 abnormal patterns based on the classification of the International Fundus Autofluorescence Classification Group, The presence of normal fundus autofluorescence, geographic atrophy, and wet age-related macular degeneration (AMD) also was recorded. The fundus findings at baseline and 2 years postoperatively were compared. Fifty-two eyes with a yellow-tinted IOL and 79 eyes with a colorless IOL were included. Abnormal fundus autofluorescence did not develop or increase in the yellow-tinted IOL group; however, progressive abnormal fundus autofluorescence developed or increased in 12 eyes (15.2%) in the colorless IOL group (P = .0016). New drusen, geographic atrophy, and choroidal neovascularization were observed mainly in the colorless IOL group. The incidence of AMD was statistically significantly higher in the colorless IOL group (P = .042). Two years after cataract surgery, significant differences were seen in the progression of abnormal fundus autofluorescence between the 2 groups. The incidence of AMD was lower in eyes with a yellow-tinted IOL. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. Female Sprague Dawley Rats Show Impaired Spatial Memory in the 8-Arm Radial Maze under Dim Blue and Red Light

    OpenAIRE

    Pirchl, Michael; Kemmler, Georg; Humpel, Christian

    2010-01-01

    Light intensity and wavelength strongly influence mood and cognition in humans and rodent animal models. The aim of the present study was to explore if dim white (7.6–17.7 lux) , blue (1.3–2.3 lux), and red light (0.8–1.4 lux) affect spatial memory of male and female Sprague Dawley rats in the 8-arm radial maze. Our data show that spatial memory significantly improved within 5 daily learning sessions (each 5 trials) under dim white light, which was not different between male and female rats. ...

  7. White emission from nano-structured top-emitting organic light-emitting diodes based on a blue emitting layer

    International Nuclear Information System (INIS)

    Hyun, Woo Jin; Park, Jung Jin; Park, O Ok; Im, Sang Hyuk; Chin, Byung Doo

    2013-01-01

    We demonstrated that white emission can be obtained from nano-structured top-emitting organic light-emitting diodes (TEOLEDs) based on a blue emitting layer (EML). The nano-structured TEOLEDs were fabricated on nano-patterned substrates, in which both optical micro-cavity and scattering effects occur simultaneously. Due to the combination of these two effects, the electroluminescence spectra of the nano-structured device with a blue EML exhibited not only blue but also yellow colours, which corresponded to the intrinsic emission of the EML and the resonant emission of the micro-cavity effect. Consequently, it was possible to produce white emission from nano-structured TEOLEDs without employing a multimode micro-cavity. The intrinsic emission wavelength can be varied by altering the dopant used for the EML. Furthermore, the emissive characteristics turned out to be strongly dependent on the nano-pattern sizes of the nano-structured devices. (paper)

  8. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin

    Science.gov (United States)

    Cai, Qing; Ren, Qu; Wei, Lizhao

    2015-01-01

    Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25–3.12 μM) has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes. PMID:26382065

  9. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin.

    Directory of Open Access Journals (Sweden)

    Tianhui Niu

    Full Text Available Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25-3.12 μM has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes.

  10. Introduction of Red-Green-Blue Fluorescent Dyes into a Metal-Organic Framework for Tunable White Light Emission.

    Science.gov (United States)

    Wen, Yuehong; Sheng, Tianlu; Zhu, Xiaoquan; Zhuo, Chao; Su, Shaodong; Li, Haoran; Hu, Shengmin; Zhu, Qi-Long; Wu, Xintao

    2017-10-01

    The unique features of the metal-organic frameworks (MOFs), including ultrahigh porosities and surface areas, tunable pores, endow the MOFs with special utilizations as host matrices. In this work, various neutral and ionic guest dye molecules, such as fluorescent brighteners, coumarin derivatives, 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM), and 4-(p-dimethylaminostyryl)-1-methylpyridinium (DSM), are encapsulated in a neutral MOF, yielding novel blue-, green-, and red-phosphors, respectively. Furthermore, this study introduces the red-, green-, and blue-emitting dyes into a MOF together for the first time, producing white-light materials with nearly ideal Commission International ed'Eclairage (CIE) coordinates, high color-rendering index values (up to 92%) and quantum yields (up to 26%), and moderate correlated color temperature values. The white light is tunable by changing the content or type of the three dye guests, or the excitation wavelength. Significantly, the introduction of blue-emitting guests in the methodology makes the available MOF host more extensive, and the final white-light output more tunable and high-quality. Such strategy can be widely adopted to design and prepare white-light-emitting materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Light exposure before learning improves memory consolidation at night

    Science.gov (United States)

    Shan, Li-Li; Guo, Hao; Song, Ning-Ning; Jia, Zheng-Ping; Hu, Xin-Tian; Huang, Jing-Fei; Ding, Yu-Qiang; Richter-Levine, Gal; Zhou, Qi-Xin; Xu, Lin

    2015-01-01

    Light is recently recognized as a modulator able to activate the hippocampus and modulate memory processing, but little is known about the molecular mechanisms. Here, we report that in mice, a short pulse of white light before learning dramatically improves consolidation of contextual fear memory during the night. The light exposure increases hippocampal active p21-activated kinase 1 (PAK1) and CA1 long-term potentiation (LTP). These light effects are abolished in PAK1 knockout and dominant-negative transgenic mice, but preserved by expression of constitutively active PAK1 in the hippocampus. Our results indicate that light can act as a switch of PAK1 activity that modulate CA1 LTP and thereby memory consolidation without affecting learning and short-term memory. PMID:26493375

  12. Sleep-Wake Actigraphy and Light Exposure During Spaceflight - Short

    Science.gov (United States)

    Czeisler, Charles A.; Wright, Kenneth P., Jr.; Ronda, Joseph

    2009-01-01

    Sleep-Wake Actigraphy and Light Exposure During Spaceflight - Short (Sleep-Short) will examine the effects of spaceflight on the sleep of the astronauts during space shuttle missions. Advancing state-of-the-art technology for monitoring, diagnosing and assessing treatment of sleep patterns is vital to treating insomnia on Earth and in space.

  13. The first neural probe integrated with light source (blue laser diode) for optical stimulation and electrical recording.

    Science.gov (United States)

    Park, HyungDal; Shin, Hyun-Joon; Cho, Il-Joo; Yoon, Eui-sung; Suh, Jun-Kyo Francis; Im, Maesoon; Yoon, Euisik; Kim, Yong-Jun; Kim, Jinseok

    2011-01-01

    In this paper, we report a neural probe which can selectively stimulate target neurons optically through Si wet etched mirror surface and record extracellular neural signals in iridium oxide tetrodes. Consequently, the proposed approach provides to improve directional problem and achieve at least 150/m gap distance between stimulation and recording sites by wet etched mirror surface in V-groove. Also, we developed light source, blue laser diode (OSRAM Blue Laser Diode_PL 450), integration through simple jig for one-touch butt-coupling. Furthermore, optical power and impedance of iridium oxide tetrodes were measured as 200 μW on 5 mW from LD and 206.5 k Ω at 1 kHz and we demonstrated insertion test of probe in 0.5% agarose-gel successfully. We have successfully transmitted a light of 450 nm to optical fiber through the integrated LD using by butt-coupling method.

  14. Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

    Directory of Open Access Journals (Sweden)

    Arno Schmidt-Trucksäss

    2017-05-01

    Full Text Available Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range age of 23 (21; 29 years and maximum oxygen uptake (VO2max of 63 (58; 66 ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT, blue monochromatic light (BLUE, and control light (CONTROL. Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm. Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004 and a melatonin decrease of −0.9 pg/ml (95% confidence interval: −1.5, −0.3; P = 0.006. Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent

  15. Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

    Science.gov (United States)

    Knaier, Raphael; Schäfer, Juliane; Rossmeissl, Anja; Klenk, Christopher; Hanssen, Henner; Höchsmann, Christoph; Cajochen, Christian; Schmidt-Trucksäss, Arno

    2017-01-01

    Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range) age of 23 (21; 29) years and maximum oxygen uptake (VO2max) of 63 (58; 66) ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT), blue monochromatic light (BLUE), and control light (CONTROL). Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm). Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm) measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004) and a melatonin decrease of −0.9 pg/ml (95% confidence interval: −1.5, −0.3; P = 0.006). Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent an

  16. Low-intensity blue-enriched white light (750 lux) and standard bright light (10,000 lux) are equally effective in treating SAD. A randomized controlled study.

    Science.gov (United States)

    Meesters, Ybe; Dekker, Vera; Schlangen, Luc J M; Bos, Elske H; Ruiter, Martine J

    2011-01-28

    Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT) of SAD with treatment using short-wavelength blue-enriched white light (BLT). Both treatments used the same illuminance (10,000 lux) and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on SAD. Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT. In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD) were given light treatment (10,000 lux) for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000 °K) with the EnergyLight® (Philips, Consumer Lifestyle) with a vertical illuminance of 10,000 lux at eye position or BLT (17,000 °K) with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools. On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%). On the basis of all assessments no statistically significant differences were found between the two conditions. With sample size being small, conclusions can only be preliminary. Both treatment conditions were found to be highly effective. The therapeutic effects of low

  17. Low-intensity blue-enriched white light (750 lux and standard bright light (10 000 lux are equally effective in treating SAD. A randomized controlled study

    Directory of Open Access Journals (Sweden)

    Bos Elske H

    2011-01-01

    Full Text Available Abstract Background Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT of SAD with treatment using short-wavelength blue-enriched white light (BLT. Both treatments used the same illuminance (10 000 lux and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on SAD. Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT. Method In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD were given light treatment (10 000 lux for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000°K with the EnergyLight® (Philips, Consumer Lifestyle with a vertical illuminance of 10 000 lux at eye position or BLT (17 000°K with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools. Results On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%. On the basis of all assessments no statistically significant differences were found between the two conditions. Conclusion With sample size being small, conclusions can only be preliminary. Both treatment conditions were found

  18. Overexpression of sweet sorghum cryptochrome 1a confers hypersensitivity to blue light, abscisic acid and salinity in Arabidopsis.

    Science.gov (United States)

    Zhou, Tingting; Meng, Lingyang; Ma, Yue; Liu, Qing; Zhang, Yunyun; Yang, Zhenming; Yang, Deguang; Bian, Mingdi

    2018-02-01

    This work provides the bioinformatics, expression pattern and functional analyses of cryptochrome 1a from sweet sorghum (SbCRY1a), together with an exploration of the signaling mechanism mediated by SbCRY1a. Sweet sorghum [Sorghum bicolor (L.) Moench] is considered to be an ideal candidate for biofuel production due to its high efficiency of photosynthesis and the ability to maintain yield under harsh environmental conditions. Blue light receptor cryptochromes regulate multiple aspects of plant growth and development. Here, we reported the function and signal mechanism of sweet sorghum cryptochrome 1a (SbCRY1a) to explore its potential for genetic improvement of sweet sorghum varieties. SbCRY1a transcripts experienced almost 24 h diurnal cycling; however, its protein abundance showed no oscillation. Overexpression of SbCRY1a in Arabidopsis rescued the phenotype of cry1 mutant in a blue light-specific manner and regulated HY5 accumulation under blue light. SbCRY1a protein was present in both nucleus and cytoplasm. The photoexcited SbCRY1a interacted directly with a putative RING E3 ubiquitin ligase constitutive photomorphogenesis 1 (COP1) from sweet sorghum (SbCOP1) instead of SbSPA1 to suppress SbCOP1-SbHY5 interaction responding to blue light. These observations indicate that the function and signaling mechanism of cryptochromes are basically conservative between monocotyledons and dicotyledons. Moreover, SbCRY1a-overexpressed transgenic Arabidopsis showed oversensitive to abscisic acid (ABA) and salinity. The ABA-responsive gene ABI5 was up-regulated evidently in SbCRY1a transgenic lines, suggesting that SbCRY1a might regulate ABA signaling through the HY5-ABI5 regulon.

  19. Blue light treatment of Pseudomonas aeruginosa: Strong bactericidal activity, synergism with antibiotics and inactivation of virulence factors.

    Science.gov (United States)

    Fila, Grzegorz; Kawiak, Anna; Grinholc, Mariusz Stanislaw

    2017-08-18

    Pseudomonas aeruginosa is among the most common pathogens responsible for both acute and chronic infections of high incidence and severity. Additionally, P. aeruginosa resistance to conventional antimicrobials has increased rapidly over the past decade. Therefore, it is crucial to explore new therapeutic options, particularly options that specifically target the pathogenic mechanisms of this microbe. The ability of a pathogenic bacterium to cause disease is dependent upon the production of agents termed 'virulence factors', and approaches to mitigate these agents have gained increasing attention as new antibacterial strategies. Although blue light irradiation is a promising alternative approach, only limited and preliminary studies have described its effect on virulence factors. The current study aimed to investigate the effects of lethal and sub-lethal doses of blue light treatment (BLT) on P. aeruginosa virulence factors. We analyzed the inhibitory effects of blue light irradiation on the production/activity of several virulence factors. Lethal BLT inhibited the activity of pyocyanin, staphylolysin, pseudolysin and other proteases, but sub-lethal BLT did not affect the production/expression of proteases, phospholipases, and flagella- or type IV pili-associated motility. Moreover, a eukaryotic cytotoxicity test confirmed the decreased toxicity of blue light-treated extracellular P. aeruginosa fractions. Finally, the increased antimicrobial susceptibility of P. aeruginosa treated with sequential doses of sub-lethal BLT was demonstrated with a checkerboard test. Thus, this work provides evidence-based proof of the susceptibility of drug-resistant P. aeruginosa to BLT-mediated killing, accompanied by virulence factor reduction, and describes the synergy between antibiotics and sub-lethal BLT.

  20. Optimization of sensitometric properties of blue and green light sensitive dental radiographic films employing an automatic processor

    OpenAIRE

    Suchetha N Malleshi; Karthikeya Patil; Mahima V Guledgud

    2011-01-01

    Background: Accurate film processing is of paramount importance in acquiring a good diagnostic radiograph. Radiographic films show variations in densities and contrast, with changes in processing conditions, and also film type, all of which are interdependent. Therefore, this research was conducted to recognize the effect of time and temperature variations of automatic processor on the sensitometric properties of blue and green light sensitive screen films. The study also aimed to note the ef...

  1. High-efficiency pyrene-based blue light emitting diodes: Aggregation suppression using a calixarene 3D-scaffold

    KAUST Repository

    Chan, Khaileok

    2012-01-01

    An efficient blue light emitting diode based on solution processable pyrene-1,3-alt-calix[4]arene is demonstrated, providing a record current efficiency of 10.5 cd A -1 in a simple non-doped OLED configuration. Complete suppression of pyrene aggregation in the solid state is achieved by controlling chromophore dispersion using the 1,3-alt-calix[4]arene scaffold. © 2012 The Royal Society of Chemistry.

  2. High speed visible light communication using blue GaN laser diodes

    Science.gov (United States)

    Watson, S.; Viola, S.; Giuliano, G.; Najda, S. P.; Perlin, P.; Suski, T.; Marona, L.; Leszczyński, M.; Wisniewski, P.; Czernecki, R.; Targowski, G.; Watson, M. A.; White, H.; Rowe, D.; Laycock, L.; Kelly, A. E.

    2016-10-01

    GaN-based laser diodes have been developed over the last 20 years making them desirable for many security and defence applications, in particular, free space laser communications. Unlike their LED counterparts, laser diodes are not limited by their carrier lifetime which makes them attractive for high speed communication, whether in free space, through fiber or underwater. Gigabit data transmission can be achieved in free space by modulating the visible light from the laser with a pseudo-random bit sequence (PRBS), with recent results approaching 5 Gbit/s error free data transmission. By exploiting the low-loss in the blue part of the spectrum through water, data transmission experiments have also been conducted to show rates of 2.5 Gbit/s underwater. Different water types have been tested to monitor the effect of scattering and to see how this affects the overall transmission rate and distance. This is of great interest for communication with unmanned underwater vehicles (UUV) as the current method using acoustics is much slower and vulnerable to interception. These types of laser diodes can typically reach 50-100 mW of power which increases the length at which the data can be transmitted. This distance could be further improved by making use of high power laser arrays. Highly uniform GaN substrates with low defectivity allow individually addressable laser bars to be fabricated. This could ultimately increase optical power levels to 4 W for a 20-emitter array. Overall, the development of GaN laser diodes will play an important part in free space optical communications and will be vital in the advancement of security and defence applications.

  3. Regulation of the subunit composition of plastidic glutamine synthetase of the wild-type and of the phytochrome-deficient aurea mutant of tomato by blue/UV-A- or by UV-B-light

    International Nuclear Information System (INIS)

    Migge, A.; Carrayol, E.; Hirel, B.; Lohmann, M.; Meya, G.; Becker, T.W.

    1998-01-01

    The photomorphogenetic aurea mutant of tomato severely deficient in spectrophotometrically active phytochromes was used to study the light-regulation of the single-copy nuclear gene encoding plastidic glutamine synthetase (GS-2; EC 6.1.3.2). The de-etiolation of dark-grown aurea mutant seedling cotyledons showed an obligatory dependency on blue light. A limited red light-responsiveness of etiolated aurea cotyledons is, however, retained as seen by the stimulation of both the GS-2 transcript and protein level in the cotyledons of aurea seedlings during growth in red light. The subunits of the octameric GS-2 enzyme were represented by polypeptides with similar electrophoretic mobilities (polypeptides a) in etiolated wild-type or aurea mutant cotyledons. GS-2 proteins with similar apparent molecular masses were also seen in the cotyledons of red light-grown aurea mutant seedlings. In contrast, GS-2 polypeptides with different apparent molecular masses (polypeptides a and b) were detected in the cotyledons of wild-type seedlings grown in red light. This difference indicates that the (post-translational) modification of tomato GS-2 subunit composition is mediated by the photoreceptor phytochrome. The illumination of etiolated wild-type or aurea cotyledons with UV-A- or UV-B-light light resulted in an increase in both the GS-2 transcript and protein level. Following illumination of etiolated wild-type seedlings with UV-A-light, the relative proportion of the GS-2 polypeptides a and b was similar than upon irradiation with blue light but different than after exposure to UV-B- or red light. This result suggests the involvement of a blue/ UV-A-light-specific photoreceptor in the regulation of tomato GS-2 subunit composition. (author)

  4. Leaf Morphology, Photosynthetic Performance, Chlorophyll Fluorescence, Stomatal Development of Lettuce (Lactuca sativa L.) Exposed to Different Ratios of Red Light to Blue Light.

    Science.gov (United States)

    Wang, Jun; Lu, Wei; Tong, Yuxin; Yang, Qichang

    2016-01-01

    Red and blue light are both vital factors for plant growth and development. We examined how different ratios of red light to blue light (R/B) provided by light-emitting diodes affected photosynthetic performance by investigating parameters related to photosynthesis, including leaf morphology, photosynthetic rate, chlorophyll fluorescence, stomatal development, light response curve, and nitrogen content. In this study, lettuce plants (Lactuca sativa L.) were exposed to 200 μmol⋅m(-2)⋅s(-1) irradiance for a 16 h⋅d(-1) photoperiod under the following six treatments: monochromatic red light (R), monochromatic blue light (B) and the mixture of R and B with different R/B ratios of 12, 8, 4, and 1. Leaf photosynthetic capacity (A max) and photosynthetic rate (P n) increased with decreasing R/B ratio until 1, associated with increased stomatal conductance, along with significant increase in stomatal density and slight decrease in stomatal size. P n and A max under B treatment had 7.6 and 11.8% reduction in comparison with those under R/B = 1 treatment, respectively. The effective quantum yield of PSII and the efficiency of excitation captured by open PSII center were also significantly lower under B treatment than those under the other treatments. However, shoot dry weight increased with increasing R/B ratio with the greatest value under R/B = 12 treatment. The increase of shoot dry weight was mainly caused by increasing leaf area and leaf number, but no significant difference was observed between R and R/B = 12 treatments. Based on the above results, we conclude that quantitative B could promote photosynthetic performance or growth by stimulating morphological and physiological responses, yet there was no positive correlation between P n and shoot dry weight accumulation.

  5. Enhanced visible light photocatalytic degradation of methylene blue by F-doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wei [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 (China); Liu, Xinjuan, E-mail: lxj669635@126.com [Shanghai Nanotechnlogy Promotion Center, Shanghai 200237 (China); Center for Coordination Bond and Electronic Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 (China); Li, Jinliang; Liu, Junying [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 (China); Zhang, Jing; Li, Ping; Chen, Chen [Shanghai Nanotechnlogy Promotion Center, Shanghai 200237 (China); Sun, Zhuo [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2014-11-15

    Graphical abstract: F-doped TiO2 is synthesized using a modified sol–gel method for visible photocatalytic degradation of MB with a high degradation rate of 91%. - Highlights: • F-doped TiO{sub 2} are synthesized using a modified sol–gel method. • The photocatalytic degradation of methylene blue by F-doped TiO{sub 2} is investigated. • A high methylene blue degradation rate of 91% is achieved under visible light irradiation. - Abstract: F-doped TiO{sub 2} (F-TiO{sub 2}) were successfully synthesized using a modified sol–gel method. The morphologies, structures, and photocatalytic performance in the degradation of methylene blue (MB) were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–vis absorption spectroscopy, and electrochemical impedance spectra, respectively. The results show that F-TiO{sub 2} exhibits an enhanced photocatalytic performance in the degradation of MB with a maximum degradation rate of 91% under visible light irradiation as compared with pure TiO{sub 2} (32%). The excellent photocatalytic activity is due to the contribution from the increased visible light absorption, promoted separation of photo-generated electrons and holes as well as enhanced photocatalytic oxidizing species with the doping of F in TiO{sub 2}.

  6. Effect of Blue Light on Endogenous Isopentenyladenine and Endoreduplication during Photomorphogenesis and De-Etiolation of Tomato (Solanum lycopersicum L.) Seedlings

    Science.gov (United States)

    Bergougnoux, Véronique; Zalabák, David; Jandová, Michaela; Novák, Ondřej; Wiese-Klinkenberg, Anika; Fellner, Martin

    2012-01-01

    Light is one of the most important factor influencing plant growth and development all through their life cycle. One of the well-known light-regulated processes is de-etiolation, i.e. the switch from skotomorphogenesis to photomorphogenesis. The hormones cytokinins (CKs) play an important role during the establishment of photomorphogenesis as exogenous CKs induced photomorphogenesis of dark-grown seedlings. Most of the studies are conducted on the plant model Arabidopsis, but no or few information are available for important crop species, such as tomato (Solanum lycopersicum L.). In our study, we analyzed for the first time the endogenous CKs content in tomato hypocotyls during skotomorphogenesis, photomorphogenesis and de-etiolation. For this purpose, two tomato genotypes were used: cv. Rutgers (wild-type; WT) and its corresponding mutant (7B-1) affected in its responses to blue light (BL). Using physiological and molecular approaches, we identified that the skotomorphogenesis is characterized by an endoreduplication-mediated cell expansion, which is inhibited upon BL exposure as seen by the accumulation of trancripts encoding CycD3, key regulators of the cell cycle. Our study showed for the first time that iP (isopentenyladenine) is the CK accumulated in the tomato hypocotyl upon BL exposure, suggesting its specific role in photomorphogenesis. This result was supported by physiological experiments and gene expression data. We propose a common model to explain the role and the relationship between CKs, namely iP, and endoreduplication during de-etiolation and photomorphogenesis. PMID:23049779

  7. Uveal melanoma in relation to ultraviolet light exposure and host factors.

    Science.gov (United States)

    Holly, E A; Aston, D A; Char, D H; Kristiansen, J J; Ahn, D K

    1990-09-15

    We conducted a case-control interview study among 1277 subjects (407 patients, 870 controls selected by using random digit dial) in 11 western United States to determine whether uveal melanoma and cutaneous melanoma shared common risk factors. After adjustment for other factors, the risk of uveal melanoma was increased for those with green, gray, or hazel eyes [relative risk (RR) = 2.5, P less than 0.001] or blue eyes (RR = 2.2, P less than 0.001) when compared to brown. A tendency to sunburn after 0.5 h midday summer sun exposure increased risk for uveal melanoma (burn with tanning RR = 1.5, P = 0.02; burn with little tanning RR = 1.8, P less than 0.001; burn with no tanning RR = 1.7, P = 0.002); as did exposure to UV or black lights (RR = 3.7, P = 0.003); and welding burn, sunburn of the eye, or snow blindness (RR = 7.2, P less than 0.001). An association with uveal melanoma was also noted with an increasing number of large nevi (P = 0.04 for trend), although the individual risk estimates were not remarkable. These data suggest that host factors and exposure to UV light are risk factors for uveal melanoma.

  8. Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression

    Directory of Open Access Journals (Sweden)

    Hidemasa Torii

    2017-02-01

    Full Text Available Prevalence of myopia is increasing worldwide. Outdoor activity is one of the most important environmental factors for myopia control. Here we show that violet light (VL, 360–400 nm wavelength suppresses myopia progression. First, we confirmed that VL suppressed the axial length (AL elongation in the chick myopia model. Expression microarray analyses revealed that myopia suppressive gene EGR1 was upregulated by VL exposure. VL exposure induced significantly higher upregulation of EGR1 in chick chorioretinal tissues than blue light under the same conditions. Next, we conducted clinical research retrospectively to compare the AL elongation among myopic children who wore eyeglasses (VL blocked and two types of contact lenses (partially VL blocked and VL transmitting. The data showed the VL transmitting contact lenses suppressed myopia progression most. These results suggest that VL is one of the important outdoor environmental factors for myopia control. Since VL is apt to be excluded from our modern society due to the excessive UV protection, VL exposure can be a preventive strategy against myopia progression.

  9. Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa.

    Directory of Open Access Journals (Sweden)

    Theoharis eOuzounis

    2015-02-01

    Full Text Available To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. ’Batavia’ (green and cv. ‘Lollo Rossa’ (red] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T lamps yielding 90 (±10 µmol m-2 s-1 for up to 20 hr, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED light treatments were Control (no blue addition, 1B 06-08 (Blue light at 45 µmol m-2 s-1 from 06:00 to 08:00, 1B 21-08 (Blue light at 45 µmol m-2 s-1 from 21:00 to 08:00, 2B 17-19 (Blue at 80 µmol m-2 s-1 from 17:00 to 19:00, and (1B 17-19 Blue at 45 µmol m-2 s-1from 17:00 to 19:00. Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent.

  10. Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa.

    Science.gov (United States)

    Ouzounis, Theoharis; Razi Parjikolaei, Behnaz; Fretté, Xavier; Rosenqvist, Eva; Ottosen, Carl-Otto

    2015-01-01

    To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. "Batavia" (green) and cv. "Lollo Rossa" (red)] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T) lamps yielding 90 (±10) μmol m(-2) s(-1) for up to 20 h, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED) light treatments were Control (no blue addition), 1B 06-08 (Blue light at 45 μmol m(-2) s(-1) from 06:00 to 08:00), 1B 21-08 (Blue light at 45 μmol m(-2) s(-1) from 21:00 to 08:00), 2B 17-19 (Blue at 80 μmol m(-2) s(-1) from 17:00 to 19:00), and 1B 17-19 (Blue at 45 μmol m(-2) s(-1) from 17:00 to 19:00). Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent.

  11. Predawn and high intensity application of supplemental blue light decreases the quantum yield of PSII and enhances the amount of phenolic acids, flavonoids, and pigments in Lactuca sativa

    Science.gov (United States)

    Ouzounis, Theoharis; Razi Parjikolaei, Behnaz; Fretté, Xavier; Rosenqvist, Eva; Ottosen, Carl-Otto

    2015-01-01

    To evaluate the effect of blue light intensity and timing, two cultivars of lettuce [Lactuca sativa cv. “Batavia” (green) and cv. “Lollo Rossa” (red)] were grown in a greenhouse compartment in late winter under natural light and supplemental high pressure sodium (SON-T) lamps yielding 90 (±10) μmol m−2 s−1 for up to 20 h, but never between 17:00 and 21:00. The temperature in the greenhouse compartments was 22/11°C day/night, respectively. The five light-emitting diode (LED) light treatments were Control (no blue addition), 1B 06-08 (Blue light at 45 μmol m−2 s−1 from 06:00 to 08:00), 1B 21-08 (Blue light at 45 μmol m−2 s−1 from 21:00 to 08:00), 2B 17-19 (Blue at 80 μmol m−2 s−1 from 17:00 to 19:00), and 1B 17-19 (Blue at 45 μmol m−2 s−1 from 17:00 to 19:00). Total fresh and dry weight was not affected with additional blue light; however, plants treated with additional blue light were more compact. The stomatal conductance in the green lettuce cultivar was higher for all treatments with blue light compared to the Control. Photosynthetic yields measured with chlorophyll fluorescence showed different response between the cultivars; in red lettuce, the quantum yield of PSII decreased and the yield of non-photochemical quenching increased with increasing blue light, whereas in green lettuce no difference was observed. Quantification of secondary metabolites showed that all four treatments with additional blue light had higher amount of pigments, phenolic acids, and flavonoids compared to the Control. The effect was more prominent in red lettuce, highlighting that the results vary among treatments and compounds. Our results indicate that not only high light level triggers photoprotective heat dissipation in the plant, but also the specific spectral composition of the light itself at low intensities. However, these plant responses to light are cultivar dependent. PMID:25767473

  12. Low driving voltage blue, green, yellow, red and white organic light-emitting diodes with a simply double light-emitting structure.

    Science.gov (United States)

    Zhang, Zhensong; Yue, Shouzhen; Wu, Yukun; Yan, Pingrui; Wu, Qingyang; Qu, Dalong; Liu, Shiyong; Zhao, Yi

    2014-01-27

    Low driving voltage blue, green, yellow, red and white phosphorescent organic light-emitting diodes (OLEDs) with a common simply double emitting layer (D-EML) structure are investigated. Our OLEDs without any out-coupling schemes as well as n-doping strategies show low driving voltage, e.g. white OLED, respectively. This work demonstrates that the low driving voltages and high efficiencies can be simultaneously realized with a common simply D-EML structure.

  13. Comparison of light out-coupling enhancements in single-layer blue-phosphorescent organic light emitting diodes using small-molecule or polymer hosts

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yung-Ting [Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Taiwan (China); Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan 10617, Taiwan (China); Liu, Shun-Wei [Department of Electronic Engineering, Mingchi University of Technology, New Taipei, Taiwan 24301, Taiwan (China); Yuan, Chih-Hsien; Lee, Chih-Chien [Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan 10607, Taiwan (China); Ho, Yu-Hsuan; Wei, Pei-Kuen [Research Center for Applied Science Academia Sinica, Taipei, Taiwan 11527, Taiwan (China); Chen, Kuan-Yu [Chilin Technology Co., LTD, Tainan City, Taiwan 71758, Taiwan (China); Lee, Yi-Ting; Wu, Min-Fei; Chen, Chin-Ti, E-mail: cchen@chem.sinica.edu.tw, E-mail: chihiwu@cc.ee.ntu.edu.tw [Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Taiwan (China); Wu, Chih-I, E-mail: cchen@chem.sinica.edu.tw, E-mail: chihiwu@cc.ee.ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan 10617, Taiwan (China)

    2013-11-07

    Single-layer blue phosphorescence organic light emitting diodes (OLEDs) with either small-molecule or polymer hosts are fabricated using solution process and the performances of devices with different hosts are investigated. The small-molecule device exhibits luminous efficiency of 14.7 cd/A and maximum power efficiency of 8.39 lm/W, which is the highest among blue phosphorescence OLEDs with single-layer solution process and small molecular hosts. Using the same solution process for all devices, comparison of light out-coupling enhancement, with brightness enhancement film (BEF), between small-molecule and polymer based OLEDs is realized. Due to different dipole orientation and anisotropic refractive index, polymer-based OLEDs would trap less light than small molecule-based OLEDs internally, about 37% better based simulation results. In spite of better electrical and spectroscopic characteristics, including ambipolar characteristics, higher carrier mobility, higher photoluminescence quantum yield, and larger triplet state energy, the overall light out-coupling efficiency of small molecule-based devices is worse than that of polymer-based devices without BEF. However, with BEF for light out-coupling enhancement, the improved ratio in luminous flux and luminous efficiency for small molecule based device is 1.64 and 1.57, respectively, which are significantly better than those of PVK (poly-9-vinylcarbazole) devices. In addition to the theoretical optical simulation, the experimental data also confirm the origins of differential light-outcoupling enhancement. The maximum luminous efficiency and power efficiency are enhanced from 14.7 cd/A and 8.39 lm/W to 23 cd/A and 13.2 lm/W, respectively, with laminated BEF, which are both the highest so far for single-layer solution-process blue phosphorescence OLEDs with small molecule hosts.

  14. Comparison of light out-coupling enhancements in single-layer blue-phosphorescent organic light emitting diodes using small-molecule or polymer hosts

    International Nuclear Information System (INIS)

    Chang, Yung-Ting; Liu, Shun-Wei; Yuan, Chih-Hsien; Lee, Chih-Chien; Ho, Yu-Hsuan; Wei, Pei-Kuen; Chen, Kuan-Yu; Lee, Yi-Ting; Wu, Min-Fei; Chen, Chin-Ti; Wu, Chih-I

    2013-01-01

    Single-layer blue phosphorescence organic light emitting diodes (OLEDs) with either small-molecule or polymer hosts are fabricated using solution process and the performances of devices with different hosts are investigated. The small-molecule device exhibits luminous efficiency of 14.7 cd/A and maximum power efficiency of 8.39 lm/W, which is the highest among blue phosphorescence OLEDs with single-layer solution process and small molecular hosts. Using the same solution process for all devices, comparison of light out-coupling enhancement, with brightness enhancement film (BEF), between small-molecule and polymer based OLEDs is realized. Due to different dipole orientation and anisotropic refractive index, polymer-based OLEDs would trap less light than small molecule-based OLEDs internally, about 37% better based simulation results. In spite of better electrical and spectroscopic characteristics, including ambipolar characteristics, higher carrier mobility, higher photoluminescence quantum yield, and larger triplet state energy, the overall light out-coupling efficiency of small molecule-based devices is worse than that of polymer-based devices without BEF. However, with BEF for light out-coupling enhancement, the improved ratio in luminous flux and luminous efficiency for small molecule based device is 1.64 and 1.57, respectively, which are significantly better than those of PVK (poly-9-vinylcarbazole) devices. In addition to the theoretical optical simulation, the experimental data also confirm the origins of differential light-outcoupling enhancement. The maximum luminous efficiency and power efficiency are enhanced from 14.7 cd/A and 8.39 lm/W to 23 cd/A and 13.2 lm/W, respectively, with laminated BEF, which are both the highest so far for single-layer solution-process blue phosphorescence OLEDs with small molecule hosts

  15. Blue-light mediated accumulation of nuclear-encoded transcripts coding for proteins of the thylakoid membrane is absent in the phytochrome-deficient aurea mutant of tomato

    International Nuclear Information System (INIS)

    Oelmueller, R.; Kendrick, R.E.; Briggs, W.R.

    1989-01-01

    Polyclonal antibodies against pea phytochrome detect 2 protein bands (about 116 and 120 kDa) on blots of crude protein extracts and protein of microsomal preparations of dark-grown tomato seedlings. Both protein bands are undetectable in Western blots of the aurea mutant extracts. Neither protein band is detectable after isogenic wild-type seedlings are illuminated with 3 h of red light, either in the crude extract or in the membrane fraction of the irradiated seedlings; this result is consistent with the hypothesis that both bands are phytochrome. When dark-grown wild-type seedlings are illuminated with 3 h of red light or blue light against a red light background, the transcript levels for chlorophyll a/b-binding proteins of photosystem I and II, plastocyanin, and the subunit II of photosystem I increase. In all cases, the same fluence rate of blue light is much more effective than red light alone, a result that indicates the involvement of a blue/UV-A light photoreceptor in addition to the involvement of the far-red-absorbing form of phytochrome, Pfr. The aurea mutant responds neither to red light nor to blue light. Thus, no Pfr-independent induction of the four transcripts by a blue/UV-A light photoreceptor can be measured in the aurea mutant

  16. Afternoon nap and bright light exposure improve cognitive flexibility post lunch.

    Directory of Open Access Journals (Sweden)

    Hichem Slama

    Full Text Available Beneficial effects of napping or bright light exposure on cognitive performance have been reported in participants exposed to sleep loss. Nonetheless, few studies investigated the effect of these potential countermeasures against the temporary drop in performance observed in mid-afternoon, and even less so on cognitive flexibility, a crucial component of executive functions. This study investigated the impact of either an afternoon nap or bright light exposure on post-prandial alterations in task switching performance in well-rested participants. Twenty-five healthy adults participated in two randomized experimental conditions, either wake versus nap (n=15, or bright light versus placebo (n=10. Participants were tested on a switching task three times (morning, post-lunch and late afternoon sessions. The interventions occurred prior to the post-lunch session. In the nap/wake condition, participants either stayed awake watching a 30-minute documentary or had the opportunity to take a nap for 30 minutes. In the bright light/placebo condition, participants watched a documentary under either bright blue light or dim orange light (placebo for 30 minutes. The switch cost estimates cognitive flexibility and measures task-switching efficiency. Increased switch cost scores indicate higher difficulties to switch between tasks. In both control conditions (wake or placebo, accuracy switch-cost score increased post lunch. Both interventions (nap or bright light elicited a decrease in accuracy switch-cost score post lunch, which was associated with diminished fatigue and decreased variability in vigilance. Additionally, there was a trend for a post-lunch benefit of bright light with a decreased latency switch-cost score. In the nap group, improvements in accuracy switch-cost score were associated with more NREM sleep stage N1. Thus, exposure to bright light during the post-lunch dip, a countermeasure easily applicable in daily life, results in similar

  17. Effects of electron transport material on blue organ light-emitting diode with fluorescent dopant of BCzVBi.

    Science.gov (United States)

    Meng, Mei; Song, Wook; Kim, You-Hyun; Lee, Sang-Youn; Jhun, Chul-Gyu; Zhu, Fu Rong; Ryu, Dae Hyun; Kim, Woo-Young

    2013-01-01

    High efficiency blue organic light emitting diodes (OLEDs), based on 2-me-thyl-9,10-di(2-naphthyl) anthracene (MADN) doped with 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi), were fabricated using two different electron transport layers (ETLs) of tris(8-hydroxyquinolino)-aluminum (Alq3) and 4,7-di-phenyl-1,10-phenanthroline (Bphen). Bphen ETL layers favored the efficient hole-electron recombination in the emissive layer of the BCzVBi-doped blue OLEDs, leading to high luminous efficiency and quantum efficiency of 8.34 cd/A at 100 mA/cm2 and 5.73% at 100 cd/m2, respectively. Maximum luminance of blue OLED with Bphen ETL and Alq3 ETL were 10670 cd/m2, and CIExy coordinates of blue OLEDs were (0.180, 0279) and (0.155, 0.212) at 100 cd/m2.

  18. VALIDITATION OF A LIGHT QUESTIONNAIRE WITH REAL-LIFE PHOTOPIC ILLUMINANCE MEASUREMENTS: THE HARVARD LIGHT EXPOSURE ASSESSMENT QUESTIONNAIRE

    Science.gov (United States)

    Bajaj, Archna; Rosner, Bernard; Lockley, Steven; Schernhammer, Eva S.

    2011-01-01

    Background Light exposure at night is now considered a probable carcinogen. To study the effects of light on chronic diseases like cancer, methods to measure light exposure in large observational studies are needed. We aimed to investigate the validity of self-reported current light exposure. Methods We developed a self-administered semiquantitative light questionnaire, the Harvard Light Exposure Assessment (H-LEA) questionnaire, and compared photopic scores derived from this questionnaire with actual photopic and circadian measures obtained from a real-life 7-day light meter application among 132 women (85 rotating night shift workers and 47 day workers) participating in the Nurses' Health Study II. Results After adjustment for age, BMI, collection day, and night work status, the overall partial Spearman correlation between self-report of light exposure and actual photopic light measurements was 0.72 (P<0.001; Kendall τ =0.57) and 0.73 (P<0.0001; Kendall τ =0.58) when correlating circadian light measurements. There were only minimal differences in accuracy of self-report of light exposure and photopic or circadian light measurement between day (r=0.77 and 0.78, respectively) and rotating night shift workers (r=0.68 and 0.69, respectively). Conclusions The results of this study provide evidence of the criterion validity of self-reported light exposure using the H-LEA questionnaire. Impact: This questionnaire is a practical method of assessing light exposure in large scale epidemiologic studies. PMID:21737411

  19. Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcome in vitro

    Science.gov (United States)

    Helander, Linda; Krokan, Hans E.; Johnsson, Anders; Gederaas, Odrun A.; Plaetzer, Kristjan

    2014-08-01

    Hexyl 5-aminolevulinate (HAL) is a lipophilic derivative of 5-aminolevulinate, a key intermediate in biosynthesis of the photosensitizer protoporphyrin IX (PpIX). The photodynamic efficacy and cell death mode after red versus blue light illumination of HAL-induced PpIX have been examined and compared using five different cancer cell lines. LED arrays emitting at 410 and 624 nm served as homogenous and adjustable light sources. Our results show that the response after HAL-PDT is cell line specific, both regarding the shape of the dose-survival curve, the overall dose required for efficient cell killing, and the relative amount of apoptosis. The ratio between 410 and 624 nm in absorption coefficient correlates well with the difference in cell killing at the same wavelengths. In general, the PDT efficacy was several folds higher for blue light as compared with red light, as expected. However, HAL-PDT624 induced more apoptosis than HAL-PDT410 and illumination with low irradiance resulted in more apoptosis than high irradiance at the same lethal dose. This indicates differences in death modes after low and high irradiance after similar total light doses. From a treatment perspective, these differences may be important.

  20. Red versus blue light illumination in hexyl 5-aminolevulinate photodynamic therapy: the influence of light color and irradiance on the treatment outcome in vitro.

    Science.gov (United States)

    Helander, Linda; Krokan, Hans E; Johnsson, Anders; Gederaas, Odrun A; Plaetzer, Kristjan

    2014-08-01

    Hexyl 5-aminolevulinate (HAL) is a lipophilic derivative of 5-aminolevulinate, a key intermediate in biosynthesis of the photosensitizer protoporphyrin IX (PpIX). The photodynamic efficacy and cell death mode after red versus blue light illumination of HAL-induced PpIX have been examined and compared using five different cancer cell lines. LED arrays emitting at 410 and 624 nm served as homogenous and adjustable light sources. Our results show that the response after HAL-PDT is cell line specific, both regarding the shape of the dose-survival curve, the overall dose required for efficient cell killing, and the relative amount of apoptosis. The ratio between 410 and 624 nm in absorption coefficient correlates well with the difference in cell killing at the same wavelengths. In general, the PDT efficacy was several folds higher for blue light as compared with red light, as expected. However, HAL-PDT₆₂₄ induced more apoptosis than HAL-PDT₄₁₀ and illumination with low irradiance resulted in more apoptosis than high irradiance at the same lethal dose. This indicates differences in death modes after low and high irradiance after similar total light doses. From a treatment perspective, these differences may be important.

  1. Low-potential electrosynthesis of novel electroactive poly(9-fluorenemethanol) and its electrochromic and blue-light-emitting properties

    International Nuclear Information System (INIS)

    Zhang, Shimin; Qin, Leiqiang; Lu, Baoyang; Xu, Jingkun

    2013-01-01

    Highlights: ► The electropolymerization of 9-fluorenemethanol (FMO) was reported. ► Semiconducting poly(9-fluorenemethanol) (PFMO) film was electrosynthesized. ► PFMO shows favorable solubility and good redox activity and stability. ► PFMO exhibits electrochromic nature from pale brown to dark blue. ► PFMO is highly fluorescent with its emission at 418 nm and a quantum yield of 0.52. -- Abstract: In this paper we describe the electropolymerization of 9-fluorenemethanol (FMO) in boron trifluoride diethyl etherate, which leads to low-potential electrodeposition of semiconducting poly(9-fluorenemethanol) (PFMO) film under optimized conditions. The as-formed PFMO film shows favorable solubility in common organic solvents, good redox activity and stability with a conductivity of 10 −2 S cm −1 , good thermal stability, and uniform morphology. Besides, PFMO exhibits electrochromic nature with its color changing from pale brown in its reduced form to dark blue upon oxidation, but its electrochromic performances are relatively poor. Fluorescence spectral studies demonstrated that soluble PFMO is highly fluorescent with its maximum emission at 418 nm and a quantum yield of 0.52, and it can emit bright blue light under 365 nm UV light irradiation

  2. Theoretical study on alkyne-linked carbazole polymers for blue-light multifunctional materials

    International Nuclear Information System (INIS)

    Yi Ling; Wang Xueye

    2011-01-01

    This paper studied poly[(3,6-di-tert-butyl-N-hexadecyl-1,8-carbazolylene) butadiynylene] (P1), butadiynylene-linked poly (3,6-carbazole) (P2) and butadiynylene-linked poly (2,7-carbazole) (P3) through the theoretical measurements with Gaussian 03 program package. To investigate the relationship between structures and properties of these multifunctional electroluminescent materials, their geometrical structures of ground and excited-states were optimized by B3LYP/6-31G (d) and CIS/6-31G (d) methods, respectively. The lowest excitation energies (E g 's), and the maximum absorption and emission wavelengths of these polymers were calculated by time-dependent density functional theory methods (TD-DFT). The important parameters for luminescent materials were also predicated including the ionization potentials (I p 's) and electron affinities (E a 's). The calculated results show that the highest-occupied molecular orbital (HOMO) energies lift about 0.27-0.49 eV compared to N,N'-bis(naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB), suggesting the significant improved hole-accepting and transporting abilities. In addition, substitution of alkyne for carbazole resulted in a narrow band gap and a red shift of both the absorption and emission peaks. Through above calculations, it is evidenced that these polymers can be considered as candidates for excellent OLEDs with good hole-creating abilities and high blue-light emission. - Highlights: → We studied poly [(3,6-di-tert-butyl-N-hexadecyl-1,8-carbazolylene) butadiynylene] by theoretical method. → The geometrical structures of ground and excited-states had been optimized by B3LYP/6-31G (d) and CIS/6-31G (d). → The relationship between structures and properties of these multifunctional electroluminescent materials had been investigated. → These molecules are excellent candidates for multifunctional OLED materials. → The substitution of alkyne for carbazole results in a narrow band gap and a red shift of both

  3. Effects of UV-B radiation on tetraspores of Chondrus ocellatus Holm (Rhodophyta), and effects of red and blue light on repair of UV-B-induced damage

    Science.gov (United States)

    Ju, Qing; Xiao, Hui; Wang, You; Tang, Xuexi

    2015-05-01

    We evaluated the effects of red and blue light on the repair of UV-B radiation-induced damage in tetraspores of Chondrus ocellatus Holm. Tetraspores of C. ocellatus were treated with different UV-B radiation levels (0, 36, 72, 108, 144 and 180 J/m2), and thereafter subjected to PAR, darkness, or red or blue light during a 2-h repair stage, each day for 48 days. The diameters and cellular contents of cyclobutane pyrimidine dimmers (CPDs), chlorophyll a (Chl a), phycoerythrin, and UV-B-absorbing mycosporinelike amino acids (MAAs) contents of the tetraspores were determined. Our results show that low doses of UV-B radiation (36 and 72 J/m2) promoted the growth of C. ocellatus; however, increased UV-B radiation gradually reduced the C. ocellatus growth (greater than 72 J/m2). The MAAs (palythine and asterina-330) in C. ocellatus were detected and analyzed by LC/MS. Our results suggest that moderate red light could induce the growth of this alga in aquaculture. In addition, photorepair was inhibited by red light, so there may be some other DNA repair mechanism activated by red light. Blue light promoted the activity of DNA photolyase, greatly improving remediation efficiency. Red and blue lights were found to reduce the capacity of C. ocellatus to form MAAs. Therefore, PAR, red light, and blue light play different roles during the repair processes for damage induced by UV-B radiation.

  4. The photocatalytic degradation of methylene blue by green semiconductor films that is induced by irradiation by a light-emitting diode and visible light.

    Science.gov (United States)

    Yang, Chih-Chi; Doong, Ruey-An; Chen, Ku-Fan; Chen, Giin-Shan; Tsai, Yung-Pin

    2018-01-01

    This study develops a low-energy rotating photocatalytic contactor (LE-RPC) that has Cu-doped TiO 2 films coated on stainless-steel rotating disks, to experimentally evaluate the efficiency of the degradation and decolorization of methylene blue (MB) under irradiation from different light sources (visible 430 nm, light-emitting diode [LED] 460 nm, and LED 525 nm). The production of hydroxyl radicals is also examined. The experimental results show that the photocatalytic activity of TiO 2 that is doped with Cu 2+ is induced by illumination with visible light and an LED. More than 90% of methylene blue at a 10 mg/L concentration is degraded after illumination by visible light (430 nm) for 4 hr at 20 rpm. This study also demonstrates that the quantity of hydroxyl radicals produced is directly proportional to the light energy intensity. The greater the light energy intensity, the greater is the number of hydroxyl radicals produced. The CuO-doped anatase TiO 2 powder was successfully synthesized in this study by a sol-gel method. The catalytic abilities of the stainless-steel film were enhanced in the visible light regions. This study has successfully modified the nano-photocatalytic materials to drop band gap and has also successfully fixed the nano-photocatalytic materials on a substratum to effectively treat dye wastewater in the range of visible light. The results can be useful to the development of a low-energy rotating photocatalytic contactor for decontamination purposes.

  5. The Impact of Blue Light Cystoscopy with Hexaminolevulinate (HAL) on Progression of Bladder Cancer - A New Analysis.

    Science.gov (United States)

    Kamat, Ashish M; Cookson, Michael; Witjes, J Alfred; Stenzl, Arnulf; Grossman, H Barton

    2016-04-27

    Background: The International Bladder Cancer Group (IBCG) recently proposed a new definition of disease progression in non-muscle invasive bladder cancer (NMIBC), including change in T-stage, change to T2 or higher or change from low to high grade. Objective: To establish whether blue light cystoscopy with hexaminolevulinate (HAL) impacts the rate of progression and time to progression using the revised definition. Methods: An earlier long-term follow-up of a controlled Phase III study reported outcomes following blue light cystoscopy with HAL (255 patients) or white light (WL) cystoscopy (261 patients) in NMIBC patients. The data was re-analysed according to the new definition. Results: In the original analysis, after 4.5 years (median), eight HAL and 16 WL patients were deemed to have progressed (transition from NMIBC to muscle invasive bladder cancer, (T2-4)). According to the new definition, additional patients in both groups were found to have progressed: 31 (12.2%) HAL vs 46 (17.6%) WL ( p  = 0.085) with four (1.6%) HAL and 11 (4.2%) WL patients progressing from Ta to CIS. Time to progression was longer in the HAL group ( p  = 0.05). Conclusions: Applying the new IBCG definition there was a trend towards a lower rate of progression in HAL patients, particularly in those progressing from Ta to CIS. Time to progression was significantly prolonged. This suggests that patients should receive blue light cystoscopy with HAL rather than WL at resection. Adoption of the new definition could allow more patients at risk of progression to be treated appropriately earlier.

  6. Improving the color purity and efficiency of blue organic light-emitting diodes (BOLED) by adding hole-blocking layer

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.J., E-mail: chien@nuk.edu.t [Department of Applied Physics, National University of Kaohsiung, 700 Kaohsiung University Road, Nan-Tzu, Kaohsiung, Taiwan (China); Kang, C.C. [Department of Electro-Optical Engineering, Southern Taiwan University of Technology, 1 Nan-Tai St., Yung-Kang City, Tainan, Taiwan (China); Lee, T.C. [Department of Electrical Engineering, Southern Taiwan University of Technology, 1 Nan-Tai St., Yung-Kang City, Tainan, Taiwan (China); Chen, W.R.; Meen, T.H. [Department of Electronic Engineering, National Formosa University, 64 Wen-Hwa Road, Hu-Wei, Yunlin, Taiwan (China)

    2009-11-15

    This work demonstrates the fabrication of a bright blue organic light-emitting diode (BOLED) with good color purity using 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi) and bathocuproine (BCP) as the emitting layer (EML) and the hole-blocking layer (HBL), respectively. Devices were prepared by vacuum deposition on indium tin oxide (ITO)-glass substrates. The thickness of DPVBi used in the OLED has an important effect on color and efficiency. The blue luminescence is maximal at 7670 cd/m{sup 2} when 13 V is applied and the BCP thickness is 2 nm. The CIE coordinate at a luminance of 7670 cd/m{sup 2} is (0.165, 0.173). Furthermore, the current efficiency is maximum at 4.25 cd/A when 9 V is applied.

  7. Improving the color purity and efficiency of blue organic light-emitting diodes (BOLED) by adding hole-blocking layer

    International Nuclear Information System (INIS)

    Huang, C.J.; Kang, C.C.; Lee, T.C.; Chen, W.R.; Meen, T.H.

    2009-01-01

    This work demonstrates the fabrication of a bright blue organic light-emitting diode (BOLED) with good color purity using 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl (DPVBi) and bathocuproine (BCP) as the emitting layer (EML) and the hole-blocking layer (HBL), respectively. Devices were prepared by vacuum deposition on indium tin oxide (ITO)-glass substrates. The thickness of DPVBi used in the OLED has an important effect on color and efficiency. The blue luminescence is maximal at 7670 cd/m 2 when 13 V is applied and the BCP thickness is 2 nm. The CIE coordinate at a luminance of 7670 cd/m 2 is (0.165, 0.173). Furthermore, the current efficiency is maximum at 4.25 cd/A when 9 V is applied.

  8. A fluorescent stilbenoid dendrimer for solution-processed blue light emitting diodes

    Science.gov (United States)

    Coya, C.; Álvarez, A. L.; Ramos, M.; de Andrés, A.; Zaldo, C.; Gómez, R.; Segura, J. L.; Seoane, C.

    2008-04-01

    We report a solution processed blue stilbenoid dendrimer based on a 1, 3, 5 - benzene core and endowed with a periphery of electron donating and solubilizing alkoxy chains. Raman analysis it is revealed as a helpful tool to investigate changes from the pristine material to the material in the OLED structure, explaining the differences between the dendrimer single layer thin film photoluminescence (PL) and the electroluminescence (EL) dendrimer active layer emission in the device. We report a blue EL emission (439 nm) and a very promising effective mobility value of 2.55 × 10 -5 cm2/(V•s) suggesting good transport properties for non doped blue OLEDs that use air stable Al as the cathode.

  9. Carcinogenesis related to intense pulsed light and UV exposure

    DEFF Research Database (Denmark)

    Hedelund, L; Lerche, C; Wulf, H C

    2006-01-01

    This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three...... observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks...... in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent...

  10. Effects of light exposure and sleep displacement on dim light melatonin onset

    NARCIS (Netherlands)

    Gordijn, MCM; Beersma, DGM; Korte, HJ; Van den Hoofdakker, RH

    The purpose of the study was to induce in two different ways, a phase-angle difference between the circadian pacemaker and the imposed sleep-wake cycle in humans, we intended to: (i) shift the circadian pacemaker by exposure to bright light and keep the timing of the sleep-wake cycle fixed; and (ii)

  11. PtAUREO1a and PtAUREO1b knockout mutants of the diatom Phaeodactylum tricornutum are blocked in photoacclimation to blue light.

    Science.gov (United States)

    Mann, Marcus; Serif, Manuel; Jakob, Torsten; Kroth, Peter G; Wilhelm, Christian

    2017-10-01

    Aureochromes are blue light receptors specifically found in photosynthetic Stramenopiles (algae). Four different Aureochromes have been identified in the marine diatom Phaeodactylum tricornutum (PtAUREO 1a, 1b, 1c, and 2). Since blue light is necessary for high light acclimation in diatoms, it has been hypothesized that Aureochromes might play an important role in the light acclimation capacity of diatoms. This hypothesis was supported by an RNAi knockdown line of PtAUREO1a, which showed a phenotype different from wild type cells when grown in either blue or red light. Here, we show for the first time the phenotype and the photoacclimation reaction of TALEN-mediated knockout mutants of PtAUREO1a and PtAUREO1b, clearly proving the necessity of Aureochromes for light acclimation under blue light. However, both mutants do also show specific differences in their respective phenotypes. Hence, PtAUREO1a and 1b are not functionally redundant in photoacclimation to blue light, and their specific contribution needs to be clarified further. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Red, green, blue and white light upconversion emission in Yb3+/Tm3+/Ho3+ co-doped tellurite glasses

    International Nuclear Information System (INIS)

    Desirena, H; De la Rosa, E; Meza, O; Salas, P

    2011-01-01

    Several Yb 3+ /Tm 3+ /Ho 3+ co-doped transparent TeO 2 -ZnO-Na 2 O-Yb 2 O 3 -Ho 2 O 3 -Tm 2 O 3 glasses were prepared and luminescence properties were characterized. Simultaneous red, green and blue (RGB) emission were obtained after excitation at 970 nm. Colour emission was tuned from multicolour to white light with colour coordinate (0.32, 0.33) matching very well with the white reference (0.33, 0.33). Changes in colour emission were obtained by varying the intensity ratios between RGB bands that are strongly concentration dependent because of the interaction of co-dopants. The colour tunability, high quality of white light and high intensity of the emitted signal make these transparent glasses excellent candidates for applications in solid-state lighting.

  13. Recombination zone in white organic light emitting diodes with blue and orange emitting layers

    Science.gov (United States)

    Tsuboi, Taiju; Kishimoto, Tadashi; Wako, Kazuhiro; Matsuda, Kuniharu; Iguchi, Hirofumi

    2012-10-01

    White fluorescent OLED devices with a 10 nm thick blue-emitting layer and a 31 nm thick orange-emitting layer have been fabricated, where the blue-emitting layer is stacked on a hole transport layer. An interlayer was inserted between the two emitting layers. The thickness of the interlayer was changed among 0.3, 0.4, and 1.0 nm. White emission with CIE coordinates close to (0.33, 0.33) was observed from all the OLEDs. OLED with 0.3 nm thick interlayer gives the highest maximum luminous efficiency (11 cd/A), power efficiency (9 lm/W), and external quantum efficiency (5.02%). The external quantum efficiency becomes low with increasing the interlayer thickness from 0 nm to 1.0 nm. When the location of the blue- and orange-emitting layers is reversed, white emission was not obtained because of too weak blue emission. It is suggested that the electron-hole recombination zone decreases nearly exponentially with a distance from the hole transport layer.

  14. Absorption and emission spectroscopic characterization of blue-light receptor Slr1694 from Synechocystis sp. PCC6803.

    Science.gov (United States)

    Zirak, P; Penzkofer, A; Lehmpfuhl, C; Mathes, T; Hegemann, P

    2007-01-03

    The BLUF protein Slr1694 from the cyanobacterium Synechocystis sp. PCC6803 is characterized by absorption and emission spectroscopy. Slr1694 expressed from E. coli which non-covalently binds FAD, FMN, and riboflavin (called Slr1694(I)), and reconstituted Slr1694 which dominantly contains FAD (called Slr1694(II)) are investigated. The receptor conformation of Slr1694 (dark adapted form Slr1694(r)) is transformed to the putative signalling state (light adapted form Slr1694(s)) with red-shifted absorption and decreased fluorescence efficiency by blue-light excitation. In the dark at 22 degrees C, the signalling state recovers back to the initial receptor state with a time constants of about 14.2s for Slr1694(I) and 17s for Slr1694(II). Quantum yields of signalling state formation of approximately 0.63+/-0.07 for both Slr1694(I) and Slr1694(II) were determined by transient transmission measurements and intensity dependent steady-state transmission measurements. Extended blue-light excitation causes some bound flavin conversion to the hydroquinone form and some photo-degradation, both with low quantum efficiency. The flavin-hydroquinone re-oxidizes slowly back (time constant 5-9 min) to the initial flavoquinone form in the dark. A photo-cycle dynamics scheme is presented.

  15. Molecular cloning and functional analysis of a blue light receptor gene MdCRY2 from apple (Malus domestica).

    Science.gov (United States)

    Li, Yuan-Yuan; Mao, Ke; Zhao, Cheng; Zhao, Xian-Yan; Zhang, Rui-Fen; Zhang, Hua-Lei; Shu, Huai-Rui; Hao, Yu-Jin

    2013-04-01

    MdCRY2 was isolated from apple fruit skin, and its function was analyzed in MdCRY2 transgenic Arabidopsis. The interaction between MdCRY2 and AtCOP1 was found by yeast two-hybrid and BiFC assays. Cryptochromes are blue/ultraviolet-A (UV-A) light receptors involved in regulating various aspects of plant growth and development. Investigations of the structure and functions of cryptochromes in plants have largely focused on Arabidopsis (Arabidopsis thaliana), tomato (Solanum lycopersicum), pea (Pisum sativum), and rice (Oryza sativa). However, no data on the function of CRY2 are available in woody plants. In this study, we isolated a cryptochrome gene, MdCRY2, from apple (Malus domestica). The deduced amino acid sequences of MdCRY2 contain the conserved N-terminal photolyase-related domain and the flavin adenine dinucleotide (FAD) binding domain, as well as the C-terminal DQXVP-acidic-STAES (DAS) domain. Relationship analysis indicates that MdCRY2 shows the highest similarity to the strawberry FvCRY protein. The expression of MdCRY2 is induced by blue/UV-A light, which represents a 48-h circadian rhythm. To investigate the function of MdCRY2, we overexpressed the MdCRY2 gene in a cry2 mutant and wild type (WT) Arabidopsis, assessed the phenotypes of the resulting transgenic plants, and found that MdCRY2 functions to regulate hypocotyl elongation, root growth, flower initiation, and anthocyanin accumulation. Furthermore, we examined the interaction between MdCRY2 and AtCOP1 using a yeast two-hybrid assay and a bimolecular fluorescence complementation assay. These data provide functional evidence for a role of blue/UV-A light-induced MdCRY2 in controlling photomorphogenesis in apple.

  16. Efficient blue and white polymer light emitting diodes based on a well charge balanced, core modified polyfluorene derivative.

    Science.gov (United States)

    Das, Dipjyoti; Gopikrishna, Peddaboodi; Singh, Ashish; Dey, Anamika; Iyer, Parameswar Krishnan

    2016-03-14

    Fabrication of efficient blue and white polymer light-emitting diodes (PLEDs) using a well charge balanced, core modified polyfluorene derivative, poly[2,7-(9,9'-dioctylfluorene)-co-N-phenyl-1,8-naphthalimide (99:01)] (PFONPN01), is presented. The excellent film forming properties as observed from the morphological study and the enhanced electron transport properties due to the inclusion of the NPN unit in the PFO main chain resulted in improved device properties. Bright blue light was observed from single layer PLEDs with PFONPN01 as an emissive layer (EML) as well as from double layer PLEDs using tris-(8-hydroxyquinoline) aluminum (Alq3) as an electron transporting layer (ETL) and LiF/Al as a cathode. The effect of ETL thickness on the device performance was studied by varying the Alq3 thickness (5 nm, 10 nm and 20 nm) and the device with an ETL thickness of 20 nm was found to exhibit the maximum brightness value of 11 662 cd m(-2) with a maximum luminous efficiency of 4.87 cd A(-1). Further, by using this highly electroluminescent blue PFONPN01 as a host and a narrow band gap, yellow emitting small molecule, dithiophene benzothiadiazole (DBT), as a guest at three different concentrations (0.2%, 0.4% and 0.6%), WPLEDs with the ITO/PEDOT:PSS/emissive layer/Alq3(20 nm)/LiF/Al configuration were fabricated and maximum brightness values of 8025 cd m(-2), 9565 cd m(-2) and 10 180 cd m(-2) were achieved respectively. 0.4% DBT in PFONPN01 was found to give white light with Commission International de l'Echairage (CIE) coordinates of (0.31, 0.38), a maximum luminous efficiency of 6.54 cd A(-1) and a color-rendering index (CRI) value of 70.

  17. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao

    2016-05-25

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  18. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao; Ng, Tien Khee; Leonard, John T.; Pourhashemi, Arash; Nakamura, Shuji; DenBaars, Steven P.; Speck, James S.; Alyamani, Ahmed Y.; El-desouki, Munir M.; Ooi, Boon S.

    2016-01-01

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  19. Observation of intermediate bands in Eu3+ doped YPO4 host: Li+ ion effect and blue to pink light emitter

    Directory of Open Access Journals (Sweden)

    Abdul Kareem Parchur

    2012-09-01

    Full Text Available This article explores the tuning of blue to pink colour generation from Li+ ion co-doped YPO4:5Eu nanoparticles prepared by polyol method at ∼100-120 °C with ethylene glycol (EG as a capping agent. Interaction of EG molecules capped on the surface of the nanoparticles and/or created oxygen vacancies induces formation of intermediate/mid gap bands in the host structure, which is supported by UV-Visible absorption data. Strong blue and pink colors can be observed in the cases of as-prepared and 500 °C annealed samples, respectively. Co-doping of Li+ enhances the emission intensities of intermediate band as well as Eu3+. On annealing as-prepared sample to 500 °C, the intermediate band emission intensity decreases, whereas Eu3+ emission intensity increases suggesting increase of extent of energy transfer from the intermediate band to Eu3+ on annealing. Emission intensity ratio of electric to magnetic dipole transitions of Eu3+ can be varied by changing excitation wavelength. The X-ray photoelectron spectroscopy (XPS study of as-prepared samples confirms the presence of oxygen vacancies and Eu3+ but absence of Eu2+. Dispersed particles in ethanol and polymer film show the strong blue color, suggesting that these materials will be useful as probes in life science and also in light emitting device applications.

  20. Strong blue and white photoluminescence emission of BaZrO{sub 3} undoped and lanthanide doped phosphor for light emitting diodes application

    Energy Technology Data Exchange (ETDEWEB)

    Romero, V.H. [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A. P. 1-948, Leon Gto., 37160 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro, Qro. 76000 (Mexico); Velazquez-Salazar, J.J. [Department of Physics and Astronomy, The University of Texas at San Antonio One UTSA Circle, San Antonio TX 78249 (United States)

    2012-12-15

    In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for undoped BaZrO{sub 3} observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm{sup 3+} ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb{sup 3+} and Eu{sup 3+} ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides. - Graphical abstract: Strong blue emission from undoped BaZrO{sub 3} phosphor and white light emission by doping with Tb{sup 3+} (green) and Eu{sup 3+} (red) after 266 nm excitation. Highlights: Black-Right-Pointing-Pointer Blue emission from BaZrO{sub 3} phosphor. Black-Right-Pointing-Pointer Blue emission enhanced with Tm{sup 3+}. Black-Right-Pointing-Pointer White light from BaZrO{sup 3+} phosphor.

  1. Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

    International Nuclear Information System (INIS)

    Li Fushan; Chen Zhijian; Wei Wei; Cao Huayu; Gong Qihuang; Teng Feng; Qian Lei; Wang Yuanmin

    2004-01-01

    The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq 3 )) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq 3 /LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m -2 were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage

  2. Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

    Energy Technology Data Exchange (ETDEWEB)

    Li Fushan [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Chen Zhijian [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Wei Wei [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Cao Huayu [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Gong Qihuang [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Teng Feng [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Qian Lei [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Wang Yuanmin [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China)

    2004-06-21

    The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq{sub 3})) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq{sub 3}/LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m{sup -2} were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage.

  3. Dose response of hydrazine - Deproteinated tooth enamel under blue light stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuece, Ulkue Rabia, E-mail: ulkuyuce@hotmail.co [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Meric, Niyazi, E-mail: meric@ankara.edu.t [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Atakol, Orhan, E-mail: atakol@science.ankara.edu.t [Ankara University, Science Faculty, Department of Chemistry, 06100, Tandogan - Ankara (Turkey); Yasar, Fusun, E-mail: ab121310@adalet.gov.t [Council of Forensic Medicine, Ankara Branch, Ankara (Turkey)

    2010-08-15

    The beta dose response and Optically Stimulated Luminescence (OSL) signal stability characteristics of human tooth enamel deproteinated by hydrazine reagent under blue photon stimulation are reported. Removal of the protein organic component of tooth enamel resulted in a higher OSL sensitivity and slower fading of OSL signals. The effect of chemical sample preparation on the enamel sample sensitivity is discussed and further steps to make this deproteinization treatment suitable for in vitro dose reconstruction studies are suggested.

  4. Dose response of hydrazine - Deproteinated tooth enamel under blue light stimulation

    International Nuclear Information System (INIS)

    Yuece, Ulkue Rabia; Meric, Niyazi; Atakol, Orhan; Yasar, Fusun

    2010-01-01

    The beta dose response and Optically Stimulated Luminescence (OSL) signal stability characteristics of human tooth enamel deproteinated by hydrazine reagent under blue photon stimulation are reported. Removal of the protein organic component of tooth enamel resulted in a higher OSL sensitivity and slower fading of OSL signals. The effect of chemical sample preparation on the enamel sample sensitivity is discussed and further steps to make this deproteinization treatment suitable for in vitro dose reconstruction studies are suggested.

  5. Out of the Lab and into the Bathroom: Evening Short-Term Exposure to Conventional Light Suppresses Melatonin and Increases Alertness Perception

    Directory of Open Access Journals (Sweden)

    Heinz Schoepp

    2013-01-01

    Full Text Available Life in 24-h society relies on the use of artificial light at night that might disrupt synchronization of the endogenous circadian timing system to the solar day. This could have a negative impact on sleep–wake patterns and psychiatric symptoms. The aim of the study was to investigate the influence of evening light emitted by domestic and work place lamps in a naturalistic setting on melatonin levels and alertness in humans. Healthy subjects (6 male, 3 female, 22–33 years were exposed to constant dim light (<10 lx for six evenings from 7:00 p.m. to midnight. On evenings 2 through 6, 1 h before habitual bedtime, they were also exposed to light emitted by 5 different conventional lamps for 30 min. Exposure to yellow light did not alter the increase of melatonin in saliva compared to dim light baseline during (38 ± 27 pg/mL vs. 39 ± 23 pg/mL and after light exposure (39 ± 22 pg/mL vs. 44 ± 26 pg/mL. In contrast, lighting conditions including blue components reduced melatonin increase significantly both during (office daylight white: 25 ± 16 pg/mL, bathroom daylight white: 24 ± 10 pg/mL, Planon warm white: 26 ± 14 pg/mL, hall daylight white: 22 ± 14 pg/mL and after light exposure (office daylight white: 25 ± 15 pg/mL, bathroom daylight white: 23 ± 9 pg/mL, Planon warm white: 24 ± 13 pg/mL, hall daylight white: 22 ± 26 pg/mL. Subjective alertness was significantly increased after exposure to three of the lighting conditions which included blue spectral components in their spectra. Evening exposure to conventional lamps in an everyday setting influences melatonin excretion and alertness perception within 30 min.

  6. Study on enhanced lymphatic tracing of isosulfan blue injection by influence of osmotic pressure on lymphatic exposure.

    Science.gov (United States)

    Ye, Tiantian; He, Rui; Wu, Yue; Shang, Lei; Wang, Shujun

    2018-04-01

    Isosulfan blue (IB) is being used as a lymphatic tracer has been approved by the FDA in 1981. This study aimed at improving lymphatic exposure of IB injection by osmotic pressure regulation to achieve step-by step lymphatic tracing. First, IB injection with appropriate osmotic pressure, stability, and suitable pH was prepared. Next, the lymphatic tracing ability of different osmotic pressure was studied to determine the blue-stained state of IB in three-level lymph nodes after subcutaneous administration. Furthermore, pharmacokinetics of lymphatic drainage, lymph node uptake, and plasma concentration was investigate to explore the improving law of the lymphatic tracing by osmotic pressure, and combined with tissue irritation to determine the optimal osmotic pressure. At last, the tissue distribution in mice of IB injection which had the property of optimal osmotic pressure was investigated. The results showed that increasing osmotic pressure could significantly reduce injection site retention and increase IB concentration of lymph node. The lymph nodes could be obviously blue-stained by IB injection which had 938 mmol/kg osmotic pressure and would not cause inflammatory reaction and blood exposure. The tissue distribution study suggested that IB injection which had 938 mmol/kg osmotic pressure was mainly distributed into gallbladder and duodenum that verified the reports that 90% IB was excreted through the feces through biliary excretion. In conclusion, this study provides the basic study to improve lymphatic exposure of IB injection by regulate the osmotic pressure and have the potential to be the helpful guidance for the elective lymph node dissection.

  7. System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum.

    Directory of Open Access Journals (Sweden)

    Kristin Collier Valle

    Full Text Available Due to the selective attenuation of solar light and the absorption properties of seawater and seawater constituents, free-floating photosynthetic organisms have to cope with rapid and unpredictable changes in both intensity and spectral quality. We have studied the transcriptional, metabolic and photo-physiological responses to light of different spectral quality in the marine diatom Phaeodactylum tricornutum through time-series studies of cultures exposed to equal doses of photosynthetically usable radiation of blue, green and red light. The experiments showed that short-term differences in gene expression and profiles are mainly light quality-dependent. Transcription of photosynthesis-associated nuclear genes was activated mainly through a light quality-independent mechanism likely to rely on chloroplast-to-nucleus signaling. In contrast, genes encoding proteins important for photoprotection and PSII repair were highly dependent on a blue light receptor-mediated signal. Changes in energy transfer efficiency by light-harvesting pigments were spectrally dependent; furthermore, a declining trend in photosynthetic efficiency was observed in red light. The combined results suggest that diatoms possess a light quality-dependent ability to activate photoprotection and efficient repair of photodamaged PSII. In spite of approximately equal numbers of PSII-absorbed quanta in blue, green and red light, the spectral quality of light is important for diatom responses to ambient light conditions.

  8. REVIEW OF DRAFT REVISED BLUE BOOK ON ESTIMATING CANCER RISKS FROM EXPOSURE TO IONIZING RADIATION

    Science.gov (United States)

    In 1994, EPA published a report, referred to as the “Blue Book,” which lays out EPA’s current methodology for quantitatively estimating radiogenic cancer risks. A follow-on report made minor adjustments to the previous estimates and presented a partial analysis of the uncertainti...

  9. Visible-light photocatalytic degradation of methylene blue with laser-induced Ag/ZnO nanoparticles

    International Nuclear Information System (INIS)

    Whang, Thou-Jen; Hsieh, Mu-Tao; Chen, Huang-Han

    2012-01-01

    The preparation of Ag doped ZnO nanoparticles conducted through the method of laser-induction is presented in this work. The Ag/ZnO nanoparticles attained from various weight percentages of added AgNO 3 relative to ZnO were applied under visible-light irradiation for evaluating the heterogeneous photocatalytic degradations of methylene blue (MB) solutions. It was shown that the catalytic behavior of Ag/ZnO nanoparticles in the visible-light range is notably improved through the Ag deposition onto ZnO nanoparticles by the method of laser-induction with a maximum effectiveness of 92% degradation. The properties of the nanoparticles were characterized by the employments of UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and selected-area electron diffraction (SAED).

  10. The acclimation of Phaeodactylum tricornutum to blue and red light does not influence the photosynthetic light reaction but strongly disturbs the carbon allocation pattern.

    Directory of Open Access Journals (Sweden)

    Anne Jungandreas

    Full Text Available Diatoms are major contributors to the aquatic primary productivity and show an efficient acclimation ability to changing light intensities. Here, we investigated the acclimation of Phaeodactylum tricornutum to different light quality with respect to growth rate, photosynthesis rate, macromolecular composition and the metabolic profile by shifting the light quality from red light (RL to blue light (BL and vice versa. Our results show that cultures pre-acclimated to BL and RL exhibited similar growth performance, photosynthesis rates and metabolite profiles. However, light shift experiments revealed rapid and severe changes in the metabolite profile within 15 min as the initial reaction of light acclimation. Thus, during the shift from RL to BL, increased concentrations of amino acids and TCA cycle intermediates were observed whereas during the BL to RL shift the levels of amino acids were decreased and intermediates of glycolysis accumulated. Accordingly, on the time scale of hours the RL to BL shift led to a redirection of carbon into the synthesis of proteins, whereas during the BL to RL shift an accumulation of carbohydrates occurred. Thus, a vast metabolic reorganization of the cells was observed as the initial reaction to changes in light quality. The results are discussed with respect to a putative direct regulation of cellular enzymes by light quality and by transcriptional regulation. Interestingly, the short-term changes in the metabolome were accompanied by changes in the degree of reduction of the plastoquinone pool. Surprisingly, the RL to BL shift led to a severe inhibition of growth within the first 48 h which was not observed during the BL to RL shift. Furthermore, during the phase of growth arrest the photosynthetic performance did not change. We propose arguments that the growth arrest could have been caused by the reorganization of intracellular carbon partitioning.

  11. Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night.

    Science.gov (United States)

    Kozaki, Tomoaki; Kubokawa, Ayaka; Taketomi, Ryunosuke; Hatae, Keisuke

    2015-07-04

    Bright nocturnal light has been known to suppress melatonin secretion. However, bright light exposure during the day-time might reduce light-induced melatonin suppression (LIMS) at night. The effective proportion of day-time light to night-time light is unclear; however, only a few studies on accurately controlling both day- and night-time conditions have been conducted. This study aims to evaluate the effect of different day-time light intensities on LIMS. Twelve male subjects between the ages of 19 and 23 years (mean ± S.D., 20.8 ± 1.1) gave informed consent to participate in this study. They were exposed to various light conditions (day-time light conditions). They were then exposed to bright light (300 lx) again between 01:00 and 02:30 (night-time light exposure). They provided saliva samples before (00:55) and after night-time light exposure (02:30). A one-tailed paired t test yielded significant decrements of melatonin concentration after night-time light exposure under day-time dim, 100- and 300-lx light conditions. No significant differences exist in melatonin concentration between pre- and post-night-time light exposure under day-time 900- and 2700-lx light conditions. Present findings suggest the amount of light exposure needed to prevent LIMS caused by ordinary nocturnal light in individuals who have a general life rhythm (sleep/wake schedule). These findings may be useful in implementing artificial light environments for humans in, for example, hospitals and underground shopping malls.

  12. SrTiO3 Nanocube-Doped Polyaniline Nanocomposites with Enhanced Photocatalytic Degradation of Methylene Blue under Visible Light

    Directory of Open Access Journals (Sweden)

    Syed Shahabuddin

    2016-02-01

    Full Text Available The present study highlights the facile synthesis of polyaniline (PANI-based nanocomposites doped with SrTiO3 nanocubes synthesized via the in situ oxidative polymerization technique using ammonium persulfate (APS as an oxidant in acidic medium for the photocatalytic degradation of methylene blue dye. Field emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, thermogravimetric analysis (TGA, X-ray diffraction (XRD, UV–Vis spectroscopy, Brunauer–Emmett–Teller analysis (BET and Fourier transform infrared spectroscopy (FTIR measurements were used to characterize the prepared nanocomposite photocatalysts. The photocatalytic efficiencies of the photocatalysts were examined by degrading methylene blue (MB under visible light irradiation. The results showed that the degradation efficiency of the composite photocatalysts that were doped with SrTiO3 nanocubes was higher than that of the undoped polyaniline. In this study, the effects of the weight ratio of polyaniline to SrTiO3 on the photocatalytic activities were investigated. The results revealed that the nanocomposite P-Sr500 was found to be an optimum photocatalyst, with a 97% degradation efficiency after 90 min of irradiation under solar light.

  13. Highly efficient and stable white organic light emitting diode base on double recombination zones of phosphorescent blue/orange emitters.

    Science.gov (United States)

    Lee, Seok Jae; Koo, Ja Ryong; Lim, Dong Hwan; Park, Hye Rim; Kim, Young Kwan; Ha, Yunkyoung

    2011-08-01

    We demonstrated efficient and stable white phosphorescent organic light-emitting diodes (OLEDs) with double-emitting layers (D-EMLs), which were comprised of two emissive layers with a hole transport-type host of N,N'-dicarbazolyl-3,5-benzene (mCP) and a electron transport-type host of 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) with blue/orange emitters, respectively. We fabricated two type white devices with single emitting layer (S-EML) and D-EML of orange emitter, maintaining double recombination zone of blue emitter. In addition, the device architecture was developed to confine excitons inside the D-EMLs and to manage triplet excitons by controlling the charge injection. As a result, light-emitting performances of white OLED with D-EMLs were improved and showed the steady CIE coordinates compared to that with S-EML of orange emitter, which demonstrated the maximum luminous efficiency and external quantum efficiency were 21.38 cd/A and 11.09%. It also showed the stable white emission with CIE(x,y) coordinates from (x = 0.36, y = 0.37) at 6 V to (x = 0.33, y = 0.38) at 12 V.

  14. Photocurrent response of B12As2 crystals to blue light, and its temperature- dependent electrical characterizations

    Directory of Open Access Journals (Sweden)

    R. Gul

    2016-02-01

    Full Text Available With the global shortage of 3He gas, researchers worldwide are looking for alternative materials for detecting neutrons. Among the candidate materials, semiconductors are attractive because of their light weight and ease in handling. Currently, we are looking into the suitability of boron arsenide (B12As2 for this specific application. As the first step in evaluating the material qualitatively, the photo-response of B12As2 bulk crystals to light with different wavelengths was examined. The crystals showed photocurrent response to a band of 407- and 470- nm blue light. The maximum measured photoresponsivity and the photocurrent density at 0.7 V for 470 nm blue light at room temperature were 0.25 A ⋅ W−1 and 2.47 mA ⋅ cm−2, respectively. In addition to photo current measurements, the electrical properties as a function of temperature (range: 50-320 K were measured. Reliable data were obtained for the low-temperature I-V characteristics, the temperature dependence of dark current and its density, and the resistivity variations with temperature in B12As2 bulk crystals. The experiments showed an exponential dependence on temperature for the dark current, current density, and resistivity; these three electrical parameters, respectively, had a variation of a few nA to μA, 1-100 μA ⋅ cm−2 and 7.6x105-7.7x103 Ω ⋅ cm, for temperature increasing from 50 K to 320 K. The results from this study reported the first photoresponse and demonstrated that B12As2 is a potential candidate for thermal-neutron detectors.

  15. Hexaminolevulinate blue-light cystoscopy in non-muscle-invasive bladder cancer: review of the clinical evidence and consensus statement on appropriate use in the USA

    NARCIS (Netherlands)

    Daneshmand, S.; Schuckman, A.K.; Bochner, B.H.; Cookson, M.S.; Downs, T.M.; Gomella, L.G.; Grossman, H.B.; Kamat, A.M.; Konety, B.R.; Lee, C.T.; Pohar, K.S.; Pruthi, R.S.; Resnick, M.J.; Smith, N.D.; Witjes, J.A.; Schoenberg, M.P.; Steinberg, G.D.

    2014-01-01

    Hexaminolevulinate (HAL) is a tumour photosensitizer that is used in combination with blue-light cystoscopy (BLC) as an adjunct to white-light cystoscopy (WLC) in the diagnosis and management of non-muscle-invasive bladder cancer (NMIBC). Since being licensed in Europe in 2005, HAL has been used in

  16. Quantitative evaluation of plasma after methylene blue and white light treatment in four Chinese blood centers.

    Science.gov (United States)

    Chunhui, Yang; Guohui, Bian; Hong, Yang; Xiaopu, Xiao; Zherong, Bai; Mingyuan, Wang; Xinsheng, Zhang; Juanjuan, Wang; Changqing, Li; Wuping, Li

    2013-12-01

    Pathogen reduction technology is an important process in the blood safety system, including solvent/detergent treatment, filtration and methylene blue-photochemical technology (MB-PCT). To investigate the quality of MB-PCT-treated plasma, plasma samples from four Chinese blood centers were analyzed over 12 months of storage to determine the recovery of activities and levels of various plasma proteins. Ten plasma units each from the Suzhou, Yancheng, Chongqing and Shandong blood centers were divided into two aliquots. One was subjected to treatment with one of two methylene blue-photochemical technology instruments and the other was used as control. The treated and untreated sample pairs were stored at -30°C. The recovery rates of coagulation factors, inhibitor proteins, total protein, immunoglobulins, and complement proteins were measured at different time points after storage. The mean recovery of most proteins exceeded 80% after MB treatment. The exceptions were factor XI and fibrinogen, of which only 71.3-74% and 69.0-92.3% were retained during storage. The two equipment types differed in terms of residual MB concentration in the plasma samples (0.18 μM and 0.29 μM, respectively). They had similar protein recovery rates at 0.5 month but differed at later time points. The four blood centers differed significantly with regard to factor II, V, VIII and fibrinogen activities. Only the samples from the Shandong blood center met the methylene blue treated fresh frozen plasma requirement. The major factor that influenced the quality of the MB-FFP samples was the time taken between blood collection and storage. Methylene blue treated plasma showed reduced coagulation factor (CF) activity and protein levels. The MB treatment-induced damage to the proteins was acceptable at the four Chinese blood centers, but the quality of the MB-treated plasma in general was not satisfactory. The main factor affecting plasma quality may be the duration of the collection and

  17. Gigabit-per-second white light-based visible light communication using near-ultraviolet laser diode and red-, green-, and blue-emitting phosphors

    KAUST Repository

    Lee, Changmin

    2017-07-12

    Data communication based on white light generated using a near-ultraviolet (NUV) laser diode (LD) pumping red-, green-, and blue-emitting (RGB) phosphors was demonstrated for the first time. A III-nitride laser diode (LD) on a semipolar (2021) substrate emitting at 410 nm was used for the transmitter. The measured modulation bandwidth of the LD was 1 GHz, which was limited by the avalanche photodetector. The emission from the NUV LD and the RGB phosphor combination measured a color rendering index (CRI) of 79 and correlated color temperature (CCT) of 4050 K, indicating promise of this approach for creating high quality white lighting. Using this configuration, data was successfully transmitted at a rate of more than 1 Gbps. This NUV laser-based system is expected to have lower background noise from sunlight at the LD emission wavelength than a system that uses a blue LD due to the rapid fall off in intensity of the solar spectrum in the NUV spectral region.

  18. Gigabit-per-second white light-based visible light communication using near-ultraviolet laser diode and red-, green-, and blue-emitting phosphors.

    Science.gov (United States)

    Lee, Changmin; Shen, Chao; Cozzan, Clayton; Farrell, Robert M; Speck, James S; Nakamura, Shuji; Ooi, Boon S; DenBaars, Steven P

    2017-07-24

    Data communication based on white light generated using a near-ultraviolet (NUV) laser diode (LD) pumping red-, green-, and blue-emitting (RGB) phosphors was demonstrated for the first time. A III-nitride laser diode (LD) on a semipolar (2021¯)  substrate emitting at 410 nm was used for the transmitter. The measured modulation bandwidth of the LD was 1 GHz, which was limited by the avalanche photodetector. The emission from the NUV LD and the RGB phosphor combination measured a color rendering index (CRI) of 79 and correlated color temperature (CCT) of 4050 K, indicating promise of this approach for creating high quality white lighting. Using this configuration, data was successfully transmitted at a rate of more than 1 Gbps. This NUV laser-based system is expected to have lower background noise from sunlight at the LD emission wavelength than a system that uses a blue LD due to the rapid fall off in intensity of the solar spectrum in the NUV spectral region.

  19. Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light

    KAUST Repository

    Ooi, Amanda Siok Lee

    2016-09-23

    Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available horticultural lighting is suboptimal, and therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. They are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Furthermore, laser beams can be tailored to match the absorption profiles of different plant species. We have developed a prototype laser growth chamber and demonstrate that plants grown under laser illumination can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs reported previously. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteome data show that the single-wavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture.

  20. Blue-light induced accumulation of reactive oxygen species is a consequence of the Drosophila cryptochrome photocycle.

    Directory of Open Access Journals (Sweden)

    Louis-David Arthaut

    Full Text Available Cryptochromes are evolutionarily conserved blue-light absorbing flavoproteins which participate in many important cellular processes including in entrainment of the circadian clock in plants, Drosophila and humans. Drosophila melanogaster cryptochrome (DmCry absorbs light through a flavin (FAD cofactor that undergoes photoreduction to the anionic radical (FAD•- redox state both in vitro and in vivo. However, recent efforts to link this photoconversion to the initiation of a biological response have remained controversial. Here, we show by kinetic modeling of the DmCry photocycle that the fluence dependence, quantum yield, and half-life of flavin redox state interconversion are consistent with the anionic radical (FAD•- as the signaling state in vivo. We show by fluorescence detection techniques that illumination of purified DmCry results in enzymatic conversion of molecular oxygen (O2 to reactive oxygen species (ROS. We extend these observations in living cells to demonstrate transient formation of superoxide (O2•-, and accumulation of hydrogen peroxide (H2O2 in the nucleus of insect cell cultures upon DmCry illumination. These results define the kinetic parameters of the Drosophila cryptochrome photocycle and support light-driven electron transfer to the flavin in DmCry signaling. They furthermore raise the intriguing possibility that light-dependent formation of ROS as a byproduct of the cryptochrome photocycle may contribute to its signaling role.

  1. Impact of blue, red, and far-red light treatments on gene expression and steviol glycoside accumulation in Stevia rebaudiana.

    Science.gov (United States)

    Yoneda, Yuki; Nakashima, Hiroshi; Miyasaka, Juro; Ohdoi, Katsuaki; Shimizu, Hiroshi

    2017-05-01

    Stevia rebaudiana (Bertoni) Bertoni is a plant that biosynthesizes a group of natural sweeteners that are up to approximately 400 times sweeter than sucrose. The sweetening components of S. rebaudiana are steviol glycosides (SGs) that partially share their biosynthesis pathway with gibberellins (GAs). However, the molecular mechanisms through which SGs levels can be improved have not been studied. Therefore, transcription levels of several SG biosynthesis-related genes were analyzed under several light treatments involved in GA biosynthesis. We detected higher transcription of UGT85C2, which is one of the UDP-glycosyltransferases (UGTs) involved in catalyzing the sugar-transfer reaction, under red/far-red (R/FR) 1.22 light-emitting diodes (LEDs) and blue LEDs treatment. In this study, it was demonstrated that transcription levels of SG-related genes and the SGs content are affected by light treatments known to affect the GA contents. It is expected that this approach could serve as a practical way to increase SG contents using specific light treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hybrid white organic light-emitting devices based on phosphorescent iridium-benzotriazole orange-red and fluorescent blue emitters

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Zhen-Yuan, E-mail: xiazhenyuan@hotmail.com [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Su, Jian-Hua [Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237 (China); Chang, Chi-Sheng; Chen, Chin H. [Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu, Taiwan 300 (China)

    2013-03-15

    We demonstrate that high color purity or efficiency hybrid white organic light-emitting devices (OLEDs) can be generated by integrating a phosphorescent orange-red emitter, bis[4-(2H-benzotriazol-2-yl)-N,N-diphenyl-aniline-N{sup 1},C{sup 3}] iridium acetylacetonate, Ir(TBT){sub 2}(acac) with fluorescent blue emitters in two different emissive layers. The device based on deep blue fluorescent material diphenyl-[4-(2-[1,1 Prime ;4 Prime ,1 Double-Prime ]terphenyl-4-yl-vinyl)-phenyl]-amine BpSAB and Ir(TBT){sub 2}(acac) shows pure white color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33,0.30). When using sky-blue fluorescent dopant N,N Prime -(4,4 Prime -(1E,1 Prime E)-2,2 Prime -(1,4-phenylene)bis(ethene-2,1-diyl) bis(4,1-phenylene))bis(2-ethyl-6-methyl-N-phenylaniline) (BUBD-1) and orange-red phosphor with a color-tuning phosphorescent material fac-tris(2-phenylpyridine) iridium (Ir(ppy){sub 3} ), it exhibits peak luminance yield and power efficiency of 17.4 cd/A and 10.7 lm/W, respectively with yellow-white color and CIE color rendering index (CRI) value of 73. - Highlights: Black-Right-Pointing-Pointer An iridium-based orange-red phosphor Ir(TBT){sub 2}(acac) was applied in hybrid white OLEDs. Black-Right-Pointing-Pointer Duel- and tri-emitter WOLEDs were achieved with either high color purity or efficiency performance. Black-Right-Pointing-Pointer Peak luminance yield of tri-emitter WOLEDs was 17.4 cd/A with yellow-white color and color rendering index (CRI) value of 73.

  3. Hybrid white organic light-emitting devices based on phosphorescent iridium–benzotriazole orange–red and fluorescent blue emitters

    International Nuclear Information System (INIS)

    Xia, Zhen-Yuan; Su, Jian-Hua; Chang, Chi-Sheng; Chen, Chin H.

    2013-01-01

    We demonstrate that high color purity or efficiency hybrid white organic light-emitting devices (OLEDs) can be generated by integrating a phosphorescent orange–red emitter, bis[4-(2H-benzotriazol-2-yl)-N,N-diphenyl-aniline-N 1 ,C 3 ] iridium acetylacetonate, Ir(TBT) 2 (acac) with fluorescent blue emitters in two different emissive layers. The device based on deep blue fluorescent material diphenyl-[4-(2-[1,1′;4′,1″]terphenyl-4-yl-vinyl)-phenyl]-amine BpSAB and Ir(TBT) 2 (acac) shows pure white color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33,0.30). When using sky-blue fluorescent dopant N,N′-(4,4′-(1E,1′E)-2,2′-(1,4-phenylene)bis(ethene-2,1-diyl) bis(4,1-phenylene))bis(2-ethyl-6-methyl-N-phenylaniline) (BUBD-1) and orange–red phosphor with a color-tuning phosphorescent material fac-tris(2-phenylpyridine) iridium (Ir(ppy) 3 ), it exhibits peak luminance yield and power efficiency of 17.4 cd/A and 10.7 lm/W, respectively with yellow-white color and CIE color rendering index (CRI) value of 73. - Highlights: ► An iridium-based orange–red phosphor Ir(TBT) 2 (acac) was applied in hybrid white OLEDs. ► Duel- and tri-emitter WOLEDs were achieved with either high color purity or efficiency performance. ► Peak luminance yield of tri-emitter WOLEDs was 17.4 cd/A with yellow-white color and color rendering index (CRI) value of 73.

  4. Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light

    KAUST Repository

    Ooi, Amanda Siok Lee; Wong, Aloysius Tze; Ng, Tien Khee; Marondedze, Claudius; Gehring, Christoph A; Ooi, Boon S.

    2016-01-01

    Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent

  5. Penetration of UV-A, UV-B, blue, and red light into leaf tissues of pecan measured by a fiber optic microprobe system

    Science.gov (United States)

    Qi, Yadong; Bai, Shuju; Vogelmann, Thomas C.; Heisler, Gordon M.

    2003-11-01

    The depth of light penetration from the adaxial surfaces of the mature leaves of pecan (Carya illinoensis) was measured using a fiber optic microprobe system at four wavelengths: UV-B (310nm), UV-A (360 nm), blue light (430nm), and red light (680nm). The average thickness of the leaf adaxial epidermal layer was 15um and the total leaf thickness was 219um. The patterns of the light attenuation by the leaf tissues exhibited strong wavelength dependence. The leaf adaxial epidermal layer was chiefly responsible for absorbing the UV-A UV-B radiation. About 98% of 310 nm light was steeply attenuated within the first 5 um of the adaxial epidermis; thus, very little UV-B radiation was transmitted to the mesophyll tissues where contain photosynthetically sensitive sites. The adaxial epidermis also attenuated 96% of the UV-A radiation. In contrast, the blue and red light penetrated much deeper and was gradually attenutated by the leaves. The mesophyll tissues attenuated 17% of the blue light and 42% of the red light, which were available for photosynthesis use. Since the epidermal layer absorbed nearly all UV-B light, it acted as an effective filter screening out the harmful radiation and protecting photosynthetically sensitive tissues from the UV-B damage. Therefore, the epidermal function of the UV-B screening effectiveness can be regarded as one of the UV-B protection mechanisms in pecan.

  6. Distinct UV-B and UV-A/blue light signal transduction pathways induce chalcone synthase gene expression in Arabidopsis cells

    International Nuclear Information System (INIS)

    Christie, J.M.; Jenkins, G.I.

    1996-01-01

    UV and blue light control the expression of flavonoid biosynthesis genes in a range of higher plants. To investigate the signal transduction processes involved in the induction of chalcone synthase (CHS) gene expression by UV-B and UV-A/blue light, we examined the, effects of specific agonists and inhibitors of known signaling components in mammalian systems in a photomixotrophic Arabidopsis cell suspension culture. CHS expression is induced specifically by these wavelengths in the cell culture, in a manner similar to that in mature Arabidopsis leaf tissue. Both the UV-B and UV-A/blue phototransduction processes involve calcium, although the elevation of cytosolic calcium is insufficient on its own to stimulate CHS expression. The UV-A/blue light induction of CHS expression does not appear to involve calmodulin, whereas the UV-B response does; this difference indicates that the signal transduction pathways are, at least in part, distinct. We provide evidence that both pathways involve reversible protein phosphorylation and require protein synthesis. The UV-B and UV-A/blue light signaling pathways are therefore different from the phytochrome signal transduction pathway regulating CHS expression in other species

  7. Photocatalytic dechlorination of PCB 138 using leuco-methylene blue and visible light; reaction conditions and mechanisms

    International Nuclear Information System (INIS)

    Izadifard, Maryam; Langford, Cooper H.; Achari, Gopal

    2010-01-01

    A study of dechlorination of PCB 138, under visible light employing methylene blue (MB) and triethylamine (TEA) in acetonitrile/water has been conducted to investigate the details of the mechanism of dechlorination and to determine the efficiency of the process for this representative congener. Two other amines, N-methyldiethanolamine (MEDA) and (triethanolamine) TEOA also replaced TEA and two other solvents, methanol and ethanol replacing acetonitrile were examined for effects on reaction rates. The results show that PCB 138 can be dechlorinated efficiently in this photocatalytic reaction. Clarifying ambiguities in several previous reports, the reduced form of MB, leuco-methylene blue (LMB) was identified as responsible for the photoreaction with its excited state transferring an electron to PCBs; oxidized LMB (i.e. MB) is reduced back to LMB by the excess amine present. The reaction depends on a cycle driven by the amine as a sacrificial electron donor. MEDA proved to be the most efficient electron donor; apparently in consequence of the most favourable steady state concentration of LMB. Methanol and ethanol may be used to replace acetonitrile with little change in the efficiency of the reaction.

  8. Tuning Ag29 nanocluster light emission from red to blue with one and two-photon excitation.

    Science.gov (United States)

    Russier-Antoine, Isabelle; Bertorelle, Franck; Hamouda, Ramzi; Rayane, Driss; Dugourd, Philippe; Sanader, Željka; Bonačić-Koutecký, Vlasta; Brevet, Pierre-François; Antoine, Rodolphe

    2016-02-07

    We demonstrate that the tuning of the light emission from red to blue in dihydrolipoic acid (DHLA) capped Ag29 nanoclusters can be trigged with one and two photon excitations. The cluster stoichiometry was determined with mass spectrometry and found to be Ag29(DHLA)12. In a detailed optical investigation, we show that these silver nanoclusters exhibit a strong red photoluminescence visible to the naked eye and characterized by a quantum yield of nearly ∼2% upon one-photon excitation. In the nonlinear optical (NLO) study of the properties of the clusters, the two-photon excited fluorescence spectra were recorded and their first hyperpolarizability obtained. The two-photon absorption cross-section at ∼800 nm for Ag29(DHLA)12 is higher than 10(4) GM and the hyperpolarizability is 106 × 10(-30) esu at the same excitation wavelength. The two-photon excited fluorescence spectrum appears strongly blue-shifted as compared to the one-photon excited spectrum, displaying a broad band between 400 and 700 nm. The density functional theory (DFT) provides insight into the structural and electronic properties of Ag29(DHLA)12 as well as into interplay between metallic subunit or core and ligands which is responsible for unique optical properties.

  9. [Preparation and spectral analysis of a new type of blue light-emitting material delta-Alq3].

    Science.gov (United States)

    Wang, Hua; Hao, Yu-ying; Gao, Zhi-xiang; Zhou, He-feng; Xu, Bing-she

    2006-10-01

    In the present article, delta-Alq3, a new type of blue light-emitting material, was synthesized and investigated by IR spectra, XRD spectra, UV-Vis absorption spectra, photoluminescence (PL) spectra, and electroluminescence (EL) spectra. The relationship between molecular spatial structure and spectral characteristics was studied by the spectral analysis of delta-Alq3 and alpha-Alq3. Results show that a new phase of Alq3 (delta-Alq3) can be obtained by vacuum heating alpha-Alq3, and the molecular spatial structure of alpha-Alq3 changes during the vacuum heating. The molecular spatial structure of delta-Alq3 lacks symmetry compared to alpha-Alq3. This transformation can reduce the electron cloud density on phenoxide of Alq3 and weaken the intermolecular conjugated interaction between adjacent Alq3 molecules. Hence, the pi--pi* electron transition absorption peak of delta-Alq3 shifts toward short wavelength in UV-Vis absorption spectra, and the maximum emission peak of delta-Alq3 (lamda max = 480 nm) blue-shifts by 35 nm compared with that of alpha-Alq3 (lamda max = 515 nm) in PL spectra. The maximum emission peaks of delta-Alq3 and alpha-Alq3 are all at 520 nm in EL spectra.

  10. The effect of blue-enriched white light on cognitive performances and sleepiness of night-shift workers: A field study.

    Science.gov (United States)

    Motamedzadeh, Majid; Golmohammadi, Rostam; Kazemi, Reza; Heidarimoghadam, Rashid

    2017-08-01

    Night-shift works are basically accompanied by reduced cognitive performance, sleepiness, and higher possibility for human error and related incidents. It is therefore crucial to improve individuals' performance and alertness in sensitive places like industries' control room with the ultimate goal of increasing efficiency and reducing the number of possible incidents. Previous research has indicated that blue light is a critical cue for entraining circadian rhythm. As a result, the present study was an attempt to investigate whether blue-enriched white light illumination was a practical strategy to decrease sleepiness and improve cognitive performance during night shifts. The study, which adopted a before-after interventional design, was conducted among 30 control room staff members of petrochemical industry. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions (namely, 17,000K and 6500K blue-enriched white light), each lasting for a week. Assessments were conducted again at the end of these treatments. In order to measure the subjective sleepiness, Karolinska Sleepiness Scale (KSS) was utilized. Subjects also performed the Conners' Continuous Performance Test II (CPT-II) and 1-back test in order to gauge their cognitive performance, and melatonin assessment was carried out using salivary and Eliza technique. The data was analyzed using two-way repeated measure ANOVA. The results indicated that, compared to normal lighting conditions, participants' sleepiness and melatonin rhythm significantly declined when they were exposed to blue-enriched white light. Furthermore, the experimental condition had a significant effect on the reduction of working memory errors. It also decreased omission errors and the reaction time during the sustained attention task. Thus, using blue-enriched white light may be a proper ergonomic strategy for improving performance and alertness, especially during night, in

  11. Two pathogen reduction technologies--methylene blue plus light and shortwave ultraviolet light--effectively inactivate hepatitis C virus in blood products.

    Science.gov (United States)

    Steinmann, Eike; Gravemann, Ute; Friesland, Martina; Doerrbecker, Juliane; Müller, Thomas H; Pietschmann, Thomas; Seltsam, Axel

    2013-05-01

    Contamination of blood products with hepatitis C virus (HCV) can cause infections resulting in acute and chronic liver diseases. Pathogen reduction methods such as photodynamic treatment with methylene blue (MB) plus visible light as well as irradiation with shortwave ultraviolet (UVC) light were developed to inactivate viruses and other pathogens in plasma and platelet concentrates (PCs), respectively. So far, their inactivation capacities for HCV have only been tested in inactivation studies using model viruses for HCV. Recently, a HCV infection system for the propagation of infectious HCV in cell culture was developed. Inactivation studies were performed with cell culture-derived HCV and bovine viral diarrhea virus (BVDV), a model for HCV. Plasma units or PCs were spiked with high titers of cell culture-grown viruses. After treatment of the blood units with MB plus light (Theraflex MB-Plasma system, MacoPharma) or UVC (Theraflex UV-Platelets system, MacoPharma), residual viral infectivity was assessed using sensitive cell culture systems. HCV was sensitive to inactivation by both pathogen reduction procedures. HCV in plasma was efficiently inactivated by MB plus light below the detection limit already by 1/12 of the full light dose. HCV in PCs was inactivated by UVC irradiation with a reduction factor of more than 5 log. BVDV was less sensitive to the two pathogen reduction methods. Functional assays with human HCV offer an efficient tool to directly assess the inactivation capacity of pathogen reduction procedures. Pathogen reduction technologies such as MB plus light treatment and UVC irradiation have the potential to significantly reduce transfusion-transmitted HCV infections. © 2012 American Association of Blood Banks.

  12. Photocatalytic degradation of methylene blue on magnetically separable MgFe2O4 under visible light irradiation

    KAUST Repository

    Shahid, Muhammad

    2013-05-01

    A magnetically separable single-phase MgFe2O4 photocatalyst with a spinel crystal structure was synthesized by using the solid-state reaction method. The formation of spinel structure is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic measurements showed that the photocatalyst material can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for waste water treatment. The photocatalytic activity of MgFe2O4 was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe2O4 was studied by measuring their photocurrent-potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm-2 illumination. © 2013 Elsevier B.V. All rights reserved.

  13. Phototropism and Protein Phosphorylation in Higher Plants: Unilateral Blue Light Irradiation Generates a Directional Gradient of Protein Phosphorylation Across the Oat Coleoptile

    International Nuclear Information System (INIS)

    Salomon, M.; Zacherl, M.; Rüdiger, W.

    1997-01-01

    Blue light induces the phosphorylation of a 116 kDa oat protein found in plasma membrane preparations from coleoptile tips. We developed a very sensitive in vitro method that allowed us to determine the tissue distribution of protein phosphorylation after applying unilateral and bilateral blue light pulses in vivo. We found that following unilateral in vivo irradiation the degree in phosphorylation of the 116 kDa protein is significantly higher at the irradiated than at the shaded side of the coleoptile tip. This asymmetry can be considered as previously missing criterion that protein phosphorylation represents an early event within the transduction chain for phototropism. (author)

  14. Structural Insights into the HWE Histidine Kinase Family: The Brucella Blue Light-Activated Histidine Kinase Domain.

    Science.gov (United States)

    Rinaldi, Jimena; Arrar, Mehrnoosh; Sycz, Gabriela; Cerutti, María Laura; Berguer, Paula M; Paris, Gastón; Estrín, Darío Ariel; Martí, Marcelo Adrián; Klinke, Sebastián; Goldbaum, Fernando Alberto

    2016-03-27

    In response to light, as part of a two-component system, the Brucella blue light-activated histidine kinase (LOV-HK) increases its autophosphorylation, modulating the virulence of this microorganism. The Brucella histidine kinase (HK) domain belongs to the HWE family, for which there is no structural information. The HWE family is exclusively present in proteobacteria and usually coupled to a wide diversity of light sensor domains. This work reports the crystal structure of the Brucella HK domain, which presents two different dimeric assemblies in the asymmetric unit: one similar to the already described canonical parallel homodimers (C) and the other, an antiparallel non-canonical (NC) dimer, each with distinct relative subdomain orientations and dimerization interfaces. Contrary to these crystallographic structures and unlike other HKs, in solution, the Brucella HK domain is monomeric and still active, showing an astonishing instability of the dimeric interface. Despite this instability, using cross-linking experiments, we show that the C dimer is the functionally relevant species. Mutational analysis demonstrates that the autophosphorylation activity occurs in cis. The different relative subdomain orientations observed for the NC and C states highlight the large conformational flexibility of the HK domain. Through the analysis of these alternative conformations by means of molecular dynamics simulations, we also propose a catalytic mechanism for Brucella LOV-HK. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The 7B-1 mutant in tomato shows blue-light-specific resistance to osmotic stress and abscisic acid.

    Science.gov (United States)

    Fellner, Martin; Sawhney, Vipen K

    2002-03-01

    Germination of wild-type (WT) tomato ( Lycopersicon esculentum Mill.) seed is inhibited by mannitol (100-140 mM) in light, but not in darkness, suggesting that light amplifies the responsiveness of the seed to osmotic stress (M. Fellner, V.K. Sawhney (2001) Theor Appl Genet 102:215-221). Here we report that white light (W) and especially blue light (B) strongly enhance the mannitol-induced inhibition of seed germination, and that the effect of red light (R) is weak or nil. The inhibitory effect of mannitol could be completely overcome by fluridone, an inhibitor of abscisic acid (ABA) biosynthesis, indicating that mannitol inhibits seed germination via ABA accumulation in seeds. The inhibition of WT seed germination by exogenous ABA was also amplified by W or B, but not by R. In a recessive, ABA-overproducing, 7B-1 mutant of tomato, seed germination and hypocotyl growth were resistant to inhibition by mannitol or exogenous ABA, both in W or B. Experiments with fluridone suggested that inhibition of hypocotyl growth by W or B is also partially via ABA accumulation. De-etiolation in the mutant was especially less in B compared to the WT, and there was no difference in hypocotyl growth between the two genotypes in R. Our data suggest that B amplifies the responsiveness of tomato seeds and hypocotyls to mannitol and ABA, and that W- or B-specific resistance of the 7B-1 mutant to osmotic stress or ABA is a consequence of a defect in B perception or signal transduction.

  16. Influence of UV irradiation on the blue and red light photoinduced processes in azobenzene polyesters

    DEFF Research Database (Denmark)

    Rodríguez, F.J.; Sánchez, C.; Villacampa, B.

    2004-01-01

    light that yields the films into the isotropic state at room temperature (RT) was compared with the quenching from temperatures above the isotropic transition temperature Ti. UV–visible spectra of the thermally quenched films show the presence of aggregates when measured at RT. We have found that UV......Birefringence induced in a series of liquid crystalline side-chain azobenzene polyesters with different substituent groups was investigated under irradiation with 488 and 633 nm linearly polarized lights. Two different initial conditions have been used: the effect of a previous irradiation with UV...

  17. Antimicrobial photodynamic activity and cytocompatibility of Au25(Capt18 clusters photoexcited by blue LED light irradiation

    Directory of Open Access Journals (Sweden)

    Miyata S

    2017-04-01

    Full Text Available Saori Miyata,1 Hirofumi Miyaji,1 Hideya Kawasaki,2 Masaki Yamamoto,2 Erika Nishida,1 Hiroko Takita,3 Tsukasa Akasaka,4 Natsumi Ushijima,3 Toshihiko Iwanaga,5 Tsutomu Sugaya1 1Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo, 2Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita-shi, Osaka, 3Support Section for Education and Research, Hokkaido University Graduate School of Dental Medicine, 4Department of Biomedical, Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, 5Department of Anatomy, Laboratory of Histology and Cytology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan Abstract: Antimicrobial photodynamic therapy (aPDT has beneficial effects in dental treatment. We applied captopril-protected gold (Au25(Capt18 clusters as a novel photosensitizer for aPDT. Photoexcited Au clusters under light irradiation generated singlet oxygen (1O2. Accordingly, the antimicrobial and cytotoxic effects of Au25(Capt18 clusters under dental blue light-emitting diode (LED irradiation were evaluated. 1O2 generation of Au25(Capt18 clusters under blue LED irradiation (420–460 nm was detected by a methotrexate (MTX probe. The antimicrobial effects of photoexcited Au clusters (0, 5, 50, and 500 µg/mL on oral bacterial cells, such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis, were assessed by morphological observations and bacterial growth experiments. Cytotoxicity testing of Au clusters and blue LED irradiation was then performed against NIH3T3 and MC3T3-E1 cells. In addition, the biological performance of Au clusters (500 µg/mL was compared to an organic dye photosensitizer, methylene blue (MB; 10 and 100 µg/mL. We confirmed the 1O2 generation ability of Au25(Capt18 clusters through the fluorescence

  18. Growth and maturation of Penaeus indicus under blue and green light

    African Journals Online (AJOL)

    growth of the penaeid prawn Penaeus indicus was tested by comparing dim green ... light quantity and quality. tank size and/or handling stress. It was decided to ... Three circular, temperature-controlled 8000 e (2,8 m diameter) glass ... of eggs and nauplii in the water. Occasional ..... Penaeus vannamei Boone. J. expo mar.

  19. Designing metallic iron based water filters: Light from methylene blue discoloration.

    Science.gov (United States)

    Btatkeu-K, B D; Tchatchueng, J B; Noubactep, C; Caré, S

    2016-01-15

    Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Analysis of circadian properties and healthy levels of blue light from smartphones at night

    Science.gov (United States)

    Oh, Ji Hye; Yoo, Heeyeon; Park, Hoo Keun; Do, Young Rag

    2015-06-01

    This study proposes representative figures of merit for circadian and vision performance for healthy and efficient use of smartphone displays. The recently developed figures of merit for circadian luminous efficacy of radiation (CER) and circadian illuminance (CIL) related to human health and circadian rhythm were measured to compare three kinds of commercial smartphone displays. The CIL values for social network service (SNS) messenger screens from all three displays were higher than 41.3 biolux (blx) in a dark room at night, and the highest CIL value reached 50.9 blx. These CIL values corresponded to melatonin suppression values (MSVs) of 7.3% and 11.4%, respectively. Moreover, smartphone use in a bright room at night had much higher CIL and MSV values (58.7 ~ 105.2 blx and 15.4 ~ 36.1%, respectively). This study also analyzed the nonvisual and visual optical properties of the three smartphone displays while varying the distance between the screen and eye and controlling the brightness setting. Finally, a method to possibly attenuate the unhealthy effects of smartphone displays was proposed and investigated by decreasing the emitting wavelength of blue LEDs in a smartphone LCD backlight and subsequently reducing the circadian effect of the display.

  1. Highly Efficient White Organic Light Emitting Diodes Using New Blue Fluorescence Emitter.

    Science.gov (United States)

    Kim, Seungho; Kim, Beomjin; Lee, Jaehyun; Yu, Young-Jun; Park, Jongwook

    2015-07-01

    Two different emitting compounds, 1-[1,1';3',1"]Terphenyl-5'-yl-6-(10-[1,1';3',1"]terpheny-5'-yl- anthracen-9-yl)-pyrene (TP-AP-TP) and Poly-phenylene vinylene derivative (PDY 132) were used to white OLED device. By incorporating adjacent blue and yellow emitting layers in a multi-layered structure, highly efficient white emission has been attained. The device was fabricated with a hybrid configuration structure: ITO/PEDOT (40 nm)/PDY-132 (8-50 nm)/ NPB (10 nm)/TP-AP-TP (30 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm). After fixing TP-AP-TP thickness of 30 nm by evaporation, PDY-132 thickness varied with 8, 15, 35, and 50 nm by spin coating in device. The luminance efficiency of the white devices at 10 mA/cm2 were 2.93 cd/A-6.55 cd/A. One of white devices showed 6.55 cd/A and white color of (0.290, 0.331).

  2. Design and optimization of a volume-phase holographic grating for simultaneous use with red, green, and blue light using unpolarized light.

    Science.gov (United States)

    Mahamat, Adoum H; Narducci, Frank A; Schwiegerling, James

    2016-03-01

    Volume-phase holographic (VPH) gratings have been designed for use in many areas of science and technology, such as optical communication, optical imaging, and astronomy. In this paper, the design of a volume-phase holographic grating, simultaneously optimized to operate in the red, green, and blue wavelengths, is presented along with a study of its fabrication tolerances. The grating is optimized to produce 98% efficiency at λ=532  nm and at least 75% efficiency in the region between 400 and 700 nm, when the incident light is unpolarized. The optimization is done for recording in dichromated gelatin with a thickness of 12 μm, an average refractive index of 1.5, and a refractive index modulation of 0.022.

  3. Light extraction efficiency improvement in GaN-based blue light emitting diode with two-dimensional nano-cavity structure

    International Nuclear Information System (INIS)

    Cho, Joong-Yeon; Hong, Sung-Hoon; Byeon, Kyeong-Jae; Lee, Heon

    2012-01-01

    The light extraction efficiency of light emitting diode (LED) devices was improved by embedding nano-sized two-dimensional, air cavity photonic crystal (PC) structure on the indium tin oxide (ITO) layer of GaN-based LEDs. The embedded air cavity PC structure was fabricated using a reversal imprint lithography technique. The nano-cavity patterns had a width of 560 nm, a space of 240 nm and a height of 280 nm. According to current–voltage characterization, the electrical performance of the LED devices was not degraded by the fabrication process of air cavity PC structure. The optical output power of the LED device was increased by up to 10% at a drive current of 20 mA by forming the nano-cavity PC structure on the transparent electrode of the blue LED device, which was grown on a patterned sapphire substrate, to maximize the photon extraction. Since photons are scattered with cavities and are unaffected by the packaging process, which is the encapsulation of a LED device with epoxy resin, this enhancement in light extraction efficiency will not be decreased after the packaging process.

  4. Dry etching characteristics of GaN for blue/green light-emitting diode fabrication

    International Nuclear Information System (INIS)

    Baik, K.H.; Pearton, S.J.

    2009-01-01

    The etch rates, surface morphology and sidewall profiles of features formed in GaN/InGaN/AlGaN multiple quantum well light-emitting diodes by Cl 2 -based dry etching are reported. The chlorine provides an enhancement in etch rate of over a factor of 40 relative to the physical etching provided by Ar and the etching is reactant-limited until chlorine gas flow rates of at least 50 standard cubic centimeters per minute. Mesa sidewall profile angle control is possible using a combination of Cl 2 /Ar plasma chemistry and SiO 2 mask. N-face GaN is found to etch faster than Ga-face surfaces under the same conditions. Patterning of the sapphire substrate for improved light extraction is also possible using the same plasma chemistry

  5. Photodynamics of BLUF domain proteins: a new class of the biological blue-light photoreceptors

    OpenAIRE

    Zirak Yousefabadi, Peyman

    2008-01-01

    BLUF domains are light sensors of many microorganisms. They are present in the multi-domain proteins e.g. AppA from the phototrophic proteobacterium Rhodobacter sphaeroides, YcgF from Escherichia coli, PAC (photoactive adenylyl cyclase) from the unicellular flagellate Euglena gracilis and single domain proteins e.g. BlrB from Rhodobacter sphaeroides, Slr1694 from cyanobacterium Synechocystis sp.PCC6803, and Tll0078 of the thermophilic unicellular cyanobacterium Thermosynechococcus elongates B...

  6. Dose determination with nitro blue tetrazolium containing radiochromic dye films by measuring absorbed and reflected light

    DEFF Research Database (Denmark)

    Kovács, A.; Baranyai, M.; Wojnárovits, L.

    2000-01-01

    determination in a wide dose range both by absorbance and reflectance measurements. The concept of measuring reflected light from dose labels has been discussed earlier and emerged recently due to the requirement of introducing semiquantitative label dose indicators for quarantine control. The usefulness...... of the method was studied using the newly developed radiochromic dye films as well as already existing ones. (C) 2000 Elsevier Science Ltd. All rights reserved....

  7. Photocatalytic degradation of methylene blue on Fe3+-doped TiO2 nanoparticles under visible light irradiation

    Institute of Scientific and Technical Information of China (English)

    SU Bitao; WANG Ke; BAI Jie; MU Hongmei; TONG Yongchun; MIN Shixiong; SHE Shixiong; LEI Ziqiang

    2007-01-01

    Fe3+-doped TiO2 composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy (UV-Vis) diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of Fe3+/TiO2 nanoparticles under visible light irradia-tion. The influence of doping amount of Fe3+ (ω: 0.00%-3.00%) on photocatalytic activities of TiO2 was investigated.Results show that the size of Fe3+/TiO2 particles decreases with the increase of the amount of Fe3+ and their absorptionspectra are broaden and absorption intensities are also increased. Doping Fe3+ can control the conversion of TiO2 from anatase to rutile. The doping amount of Fe3+ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The appropriate doping of Fe3+ can markedly increase the catalytic activity of TiO2 under visible light irradiation.

  8. Enhanced visible-light-response photocatalytic degradation of methylene blue on Fe-loaded BiVO{sub 4} photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Chala, Sinaporn [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Khatcharin [Program of Physics, Faculty of Science, Ubon Ratchathani Rajabhat University, Ubon Ratchathani 34000 (Thailand); Phanichphant, Sukon [Materials Science Research Centre, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Inceesungvorn, Burapat [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Natda, E-mail: natda_we@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-06-01

    Highlights: • Fe-loaded BiVO{sub 4} particles were prepared by hydrothermal method. • Physicochemical properties played a significant role in photocatalytic process. • All Fe-loaded BiVO{sub 4} samples showed higher photocatalytic activity than pure BiVO{sub 4}. • The Fe{sup 3+} ions may improve the separation of photogenerated electrons and holes. - Abstract: Pure BiVO{sub 4} and nominal 0.5–5.0 mol% Fe-loaded BiVO{sub 4} samples were synthesized by hydrothermal method. All samples were characterized in order to obtain the correlation between structure and photocatalytic properties by X-ray diffraction, Brunauer, Emmett and Teller, UV–vis diffuse reflectance spectrophotometry, photoluminescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and inductively coupled plasma-optical emission spectroscopy. The structure of all samples was single-phase monoclinic scheelite. The absorption spectrum of 5.0 mol% Fe-loaded BiVO{sub 4} shifted to the visible region, suggesting the potential application of this material as a superior visible-light driven photocatalyst in comparison with pure BiVO{sub 4}. Photocatalytic activities of all photocatalyst samples were examined by studying the degradation of methylene blue under visible light irradiation. The results clearly showed that Fe-loaded BiVO{sub 4} sample exhibited remarkably higher activity than pure BiVO{sub 4}.

  9. Enhanced visible-light-response photocatalytic degradation of methylene blue on Fe-loaded BiVO4 photocatalyst

    International Nuclear Information System (INIS)

    Chala, Sinaporn; Wetchakun, Khatcharin; Phanichphant, Sukon; Inceesungvorn, Burapat; Wetchakun, Natda

    2014-01-01

    Highlights: • Fe-loaded BiVO 4 particles were prepared by hydrothermal method. • Physicochemical properties played a significant role in photocatalytic process. • All Fe-loaded BiVO 4 samples showed higher photocatalytic activity than pure BiVO 4 . • The Fe 3+ ions may improve the separation of photogenerated electrons and holes. - Abstract: Pure BiVO 4 and nominal 0.5–5.0 mol% Fe-loaded BiVO 4 samples were synthesized by hydrothermal method. All samples were characterized in order to obtain the correlation between structure and photocatalytic properties by X-ray diffraction, Brunauer, Emmett and Teller, UV–vis diffuse reflectance spectrophotometry, photoluminescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and inductively coupled plasma-optical emission spectroscopy. The structure of all samples was single-phase monoclinic scheelite. The absorption spectrum of 5.0 mol% Fe-loaded BiVO 4 shifted to the visible region, suggesting the potential application of this material as a superior visible-light driven photocatalyst in comparison with pure BiVO 4 . Photocatalytic activities of all photocatalyst samples were examined by studying the degradation of methylene blue under visible light irradiation. The results clearly showed that Fe-loaded BiVO 4 sample exhibited remarkably higher activity than pure BiVO 4

  10. Effect of red and blue light on the timing of cyclin-dependent kinase activity and the timing of cell division in Chlamydomonas reinhardtii

    Czech Academy of Sciences Publication Activity Database

    Oldenhof, H.; Bišová, Kateřina; Ende, H.; Zachleder, Vilém

    2004-01-01

    Roč. 42, - (2004), s. 341-348 ISSN 0981-9428 R&D Projects: GA ČR GA204/02/1438 Institutional research plan: CEZ:AV0Z5020903 Keywords : blue light * chlamydomonas reingardtii * cell cycle Subject RIV: EA - Cell Biology Impact factor: 1.414, year: 2004

  11. Safety of hexaminolevulinate for blue light cystoscopy in bladder cancer. A combined analysis of the trials used for registration and postmarketing data

    NARCIS (Netherlands)

    Witjes, J.A.; Gomella, L.G.; Stenzl, A.; Chang, S.S.; Zaak, D.; Grossman, H.B.

    2014-01-01

    OBJECTIVE: To detail and put into perspective, safety of hexaminolevulinate blue light cystoscopy (HAL-BLC), including repeated use, based on combined data of controlled trials used for registration of HAL and postmarketing experience. METHODS: Safety data of 2 randomized comparative studies (group

  12. The 7B-1 mutation in tomato (Solanum lycopersicum L.) confers a blue light-specific lower sensitivity to coronatine, a toxin produced by Pseudomonas syringae pv. tomato

    Czech Academy of Sciences Publication Activity Database

    Bergougnoux, V.; Hlaváčková, V.; Plotzová, R.; Novák, Ondřej; Fellner, Martin

    2009-01-01

    Roč. 60, č. 4 (2009), s. 1219-1230 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : Blue light-specific response * COI1 * coronatine Subject RIV: EF - Botanics Impact factor: 4.271, year: 2009

  13. Modulation by phytochrome of the blue light-induced extracellular acidification by leaf epidermal cells of pea (Pisum sativum L.) : a kinetic analysis

    NARCIS (Netherlands)

    Elzenga, JTM; Staal, M; Prins, HBA

    Blue light induces extracellular acidification, a prerequisite of cell expansion, in epidermis cells of young pea leaves, by stimulation of the proton pumping-ATPase activity in the plasma membrane. A transient acidification, reaching a maximum 2.5-5 min after the start of the pulse, could be

  14. Blue and white phosphorescent organic light emitting diode performance improvement by confining electrons and holes inside double emitting layers

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yu-Sheng; Hong, Lin-Ann; Juang, Fuh-Shyang; Chen, Cheng-Yin

    2014-09-15

    In this research, complex emitting layers (EML) were fabricated using TCTA doping hole-transport material in the front half of a bipolar 26DCzPPy as well as PPT doping electron-transport material in the back half of 26DCzPPy. Blue dopant FIrpic was also mixed inside the complex emitting layer to produce a highly efficient blue phosphorescent organic light emitting diode (OLED). The hole and electron injection and carrier recombination rate were effectively increased. The fabricated complex emitting layers exhibited current efficiency of 42 cd/A and power efficiency of 30 lm/W when the luminance was 1000 cd/m{sup 2}, driving voltage was 4.4 V, and current density was 2.4 mA/cm{sup 2}. A white OLED component was then manufactured by doping red dopant [Os(bpftz){sub 2}(PPh{sub 2}Me){sub 2}] (Os) in proper locations. When the Os dopant was doped in between the complex emitting layers, excitons were effectively confined within, increasing the recombination rate and therefore reducing the color shift. The resulting Commission Internationale de L’Eclairage (CIE) coordinates shifted from 4 to 10 V is (Δx=−0.04, Δy=+0.01). The component had a current efficiency of 35.7 cd/A, a power efficiency of 24 lm/W, driving voltage of 4.6 V and a CIE{sub x,y} of (0.31,0.35) at a luminance of 1000 cd/m{sup 2}, with a maximum luminance of 15,600 cd/m{sup 2} at 10 V. Attaching an outcoupling enhancement film was applied to increase the luminance efficiency to 30 lm/W. - Highlights: • Used the complex double emitting layers. • Respectively doped hole and electron transport material in the bipolar host. • Electrons and holes are effectively confined within EMLs to produce excitons.

  15. Solution-processed small molecules as mixed host for highly efficient blue and white phosphorescent organic light-emitting diodes.

    Science.gov (United States)

    Fu, Qiang; Chen, Jiangshan; Shi, Changsheng; Ma, Dongge

    2012-12-01

    The widely used hole-transporting host 4,4',4″-tris(N-carbazolyl)-triphenylamine (TCTA) blended with either a hole-transporting or an electron-transporting small-molecule material as a mixed-host was investigated in the phosphorescent organic light-emitting diodes (OLEDs) fabricated by the low-cost solution-process. The performance of the solution-processed OLEDs was found to be very sensitive to the composition of the mixed-host systems. The incorporation of the hole-transporting 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) into TCTA as the mixed-host was demonstrated to greatly reduce the driving voltage and thus enhance the efficiency due to the improvement of hole injection and transport. On the basis of the mixed-host of TCTA:TAPC, we successfully fabricated low driving voltage and high efficiency blue and white phosphorescent OLEDs. A maximum forward viewing current efficiency of 32.0 cd/A and power efficiency of 25.9 lm/W were obtained in the optimized mixed-host blue OLED, which remained at 29.6 cd/A and 19.1 lm/W at the luminance of 1000 cd/m(2) with a driving voltage as low as 4.9 V. The maximum efficiencies of 37.1 cd/A and 32.1 lm/W were achieved in a single emissive layer white OLED based on the TCTA:TAPC mixed-host. Even at 1000 cd/m(2), the efficiencies still reach 34.2 cd/A and 23.3 lm/W and the driving voltage is only 4.6 V, which is comparable to those reported from the state-of-the-art vacuum-evaporation deposited white OLEDs.

  16. Blue and white phosphorescent organic light emitting diode performance improvement by confining electrons and holes inside double emitting layers

    International Nuclear Information System (INIS)

    Tsai, Yu-Sheng; Hong, Lin-Ann; Juang, Fuh-Shyang; Chen, Cheng-Yin

    2014-01-01

    In this research, complex emitting layers (EML) were fabricated using TCTA doping hole-transport material in the front half of a bipolar 26DCzPPy as well as PPT doping electron-transport material in the back half of 26DCzPPy. Blue dopant FIrpic was also mixed inside the complex emitting layer to produce a highly efficient blue phosphorescent organic light emitting diode (OLED). The hole and electron injection and carrier recombination rate were effectively increased. The fabricated complex emitting layers exhibited current efficiency of 42 cd/A and power efficiency of 30 lm/W when the luminance was 1000 cd/m 2 , driving voltage was 4.4 V, and current density was 2.4 mA/cm 2 . A white OLED component was then manufactured by doping red dopant [Os(bpftz) 2 (PPh 2 Me) 2 ] (Os) in proper locations. When the Os dopant was doped in between the complex emitting layers, excitons were effectively confined within, increasing the recombination rate and therefore reducing the color shift. The resulting Commission Internationale de L’Eclairage (CIE) coordinates shifted from 4 to 10 V is (Δx=−0.04, Δy=+0.01). The component had a current efficiency of 35.7 cd/A, a power efficiency of 24 lm/W, driving voltage of 4.6 V and a CIE x,y of (0.31,0.35) at a luminance of 1000 cd/m 2 , with a maximum luminance of 15,600 cd/m 2 at 10 V. Attaching an outcoupling enhancement film was applied to increase the luminance efficiency to 30 lm/W. - Highlights: • Used the complex double emitting layers. • Respectively doped hole and electron transport material in the bipolar host. • Electrons and holes are effectively confined within EMLs to produce excitons

  17. Bright light exposure reduces TH-positive dopamine neurons: implications of light pollution in Parkinson's disease epidemiology.

    Science.gov (United States)

    Romeo, Stefania; Viaggi, Cristina; Di Camillo, Daniela; Willis, Allison W; Lozzi, Luca; Rocchi, Cristina; Capannolo, Marta; Aloisi, Gabriella; Vaglini, Francesca; Maccarone, Rita; Caleo, Matteo; Missale, Cristina; Racette, Brad A; Corsini, Giovanni U; Maggio, Roberto

    2013-01-01

    This study explores the effect of continuous exposure to bright light on neuromelanin formation and dopamine neuron survival in the substantia nigra. Twenty-one days after birth, Sprague-Dawley albino rats were divided into groups and raised under different conditions of light exposure. At the end of the irradiation period, rats were sacrificed and assayed for neuromelanin formation and number of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra. The rats exposed to bright light for 20 days or 90 days showed a relatively greater number of neuromelanin-positive neurons. Surprisingly, TH-positive neurons decreased progressively in the substantia nigra reaching a significant 29% reduction after 90 days of continuous bright light exposure. This decrease was paralleled by a diminution of dopamine and its metabolite in the striatum. Remarkably, in preliminary analysis that accounted for population density, the age and race adjusted Parkinson's disease prevalence significantly correlated with average satellite-observed sky light pollution.

  18. Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison.

    Science.gov (United States)

    Heo, Jung-Yoon; Kim, Kiwon; Fava, Maurizio; Mischoulon, David; Papakostas, George I; Kim, Min-Ji; Kim, Dong Jun; Chang, Kyung-Ah Judy; Oh, Yunhye; Yu, Bum-Hee; Jeon, Hong Jin

    2017-04-01

    Smartphones deliver light to users through Light Emitting Diode (LED) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of smartphone blue light LED on humans at night. We investigated changes in serum melatonin levels, cortisol levels, body temperature, and psychiatric measures with a randomized, double-blind, cross-over, placebo-controlled design of two 3-day admissions. Each subject played smartphone games with either conventional LED or suppressed blue light from 7:30 to 10:00PM (150 min). Then, they were readmitted and conducted the same procedure with the other type of smartphone. Serum melatonin levels were measured in 60-min intervals before, during and after use of the smartphones. Serum cortisol levels and body temperature were monitored every 120 min. The Profile of Mood States (POMS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and auditory and visual Continuous Performance Tests (CPTs) were administered. Among the 22 participants who were each admitted twice, use of blue light smartphones was associated with significantly decreased sleepiness (Cohen's d = 0.49, Z = 43.50, p = 0.04) and confusion-bewilderment (Cohen's d = 0.53, Z = 39.00, p = 0.02), and increased commission error (Cohen's d = -0.59, t = -2.64, p = 0.02). Also, users of blue light smartphones experienced a longer time to reach dim light melatonin onset 50% (2.94 vs. 2.70 h) and had increases in body temperature, serum melatonin levels, and cortisol levels, although these changes were not statistically significant. Use of blue light LED smartphones at night may negatively influence sleep and commission errors, while it may not be enough to lead to significant changes in serum melatonin and cortisol levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Bright Light Delights: Effects of Daily Light Exposure on Emotions, Restactivity Cycles, Sleep and Melatonin Secretion in Severely Demented Patients.

    Science.gov (United States)

    Münch, Mirjam; Schmieder, Michael; Bieler, Katharina; Goldbach, Rolf; Fuhrmann, Timo; Zumstein, Naomi; Vonmoos, Petra; Scartezzini, Jean-Louis; Wirz-Justice, Anna; Cajochen, Christian

    2017-01-01

    We tested whether the effects of a dynamic lighting system are superior to conventional lighting on emotions, agitation behaviour, quality of life, melatonin secretion and circadian restactivity cycles in severely demented patients. As a comparison, an age matched control patient group was exposed to conventional lighting. For none of the output measures were significant differences between the two lighting conditions found during the 8 study weeks in fall/winter. Thus, we divided the patient cohort (n = 89) into two groups, solely based on the median of their daily individual light exposure. Patients with higher average daily light exposure (>417 lx) showed significantly longer emotional expressions of pleasure and alertness per daily observations than patients with lower daily light exposure. Moreover, they had a higher quality of life, spent less time in bed, went to bed later and initiated their sleep episodes later, even though the two groups did not differ with respect to age, severity of cognitive impairment and mobility. In general, men were more agitated, had shorter sleep with more wake episodes, had a lower circadian amplitude of relative rest-wake activity and interdaily circadian stability than women. In particular, lower daily light exposures significantly predicted lower circadian amplitudes of rest-activity cycles in men but not in women. This may indicate sex specific susceptibility to daily light exposures for rest-activity regulation in older demented patients. Our results provide evidence that a higher daily light exposure has beneficial effects on emotions and thus improved quality of life in a severely demented patient group. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. Blue light alters miR167 expression and microRNA-targeted auxin response factor genes in Arabidopsis thaliana plants.

    Science.gov (United States)

    Pashkovskiy, Pavel P; Kartashov, Alexander V; Zlobin, Ilya E; Pogosyan, Sergei I; Kuznetsov, Vladimir V

    2016-07-01

    The effect of blue LED (450 nm) on the photomorphogenesis of Arabidopsis thaliana Col-0 plants and the transcript levels of several genes, including miRNAs, photoreceptors and auxin response factors (ARF) was investigated. It was observed that blue light accelerated the generative development, reduced the rosette leaf number, significantly reduced the leaf area, dry biomass and led to the disruption of conductive tissue formation. The blue LED differentially influenced the transcript levels of several phytochromes (PHY a, b, c, d, and e), cryptochromes (CRY 1 and 2) and phototropins (PHOT 1 and 2). At the same time, the blue LED significantly increased miR167 expression compared to a fluorescent lamp or white LEDs. This increase likely resulted in the enhanced transcription of the auxin response factor genes ARF4 and ARF8, which are regulated by this miRNA. These findings support the hypothesis that the effects of blue light on A. thaliana are mediated by auxin signalling pathway involving miRNA-dependent regulation of ARF gene expression. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Further investigations into pulsed optically stimulated luminescence from feldspars using blue and green light

    International Nuclear Information System (INIS)

    Ankjaergaard, C.; Jain, M.; Kalchgruber, R.; Lapp, T.; Klein, D.; McKeever, S.W.S.; Murray, A.S.; Morthekai, P.

    2009-01-01

    The purpose of this paper is to investigate characteristics of luminescence signals resulting from pulsed optical stimulation of feldspars and thereby to understand the underlying processes giving rise to the signal. Fourteen different feldspar specimens were investigated using time-resolved optically stimulated luminescence (TR-OSL), and these signals can be mathematically described as a sum of 4 exponential components (a, b, c, d). The slowest component, d, increases with the duration of the light pulse as expected from the exponential model. The stimulation temperature dependence experiment suggests that the TR-OSL signal decay is governed by the recombination process and not by the excited state lifetime. Furthermore data from the TR-OSL signal dependence on stimulation time and preheat temperature suggest that the recombination process may not be a sum of exponentials, although the model cannot be rejected definitively.

  2. The blue light indicator in rubidium 5S-5P-5D cascade excitation

    Science.gov (United States)

    Raja, Waseem; Ali, Md. Sabir; Chakrabarti, Alok; Ray, Ayan

    2017-07-01

    The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump-probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon-atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits 420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.

  3. Efficient single light-emitting layer pure blue phosphorescent organic light-emitting devices with wide gap host and matched interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yunlong; Zhou, Liang, E-mail: zhoul@ciac.ac.cn; Cui, Rongzhen; Li, Yanan; Zhao, Xuesen; Zhang, Hongjie, E-mail: hongjie@ciac.ac.cn

    2015-12-15

    In this work, we report the highly efficient pure blue electroluminescent (EL) device based on bis[(3,5-difluoro-4-cyanophenyl)pyridine]picolinate iridium(III) (FCNIrpic) doped 9-(4-tert-Butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi) film. The matched energy levels of FCNIrpic and CzSi are helpful in facilitating the trapping of carriers, while the high triplet energy of CzSi can well avoid the undesired reverse energy transfer. More importantly, the injection of holes was further accelerated by inserting 5 nm 4,4′,4″-Tri(9-carbazoyl)triphenylamine (TcTa) film between hole transport layer and lighting-emitting layer (EML) as interlayer. Consequently, EL performances were significantly enhanced attributed to wider recombination zone and better balance of holes and electrons. Interestingly, single-EML device displayed higher performances than those of double-EMLs device. Finally, pure blue EL device with the structure of ITO/MoO{sub 3} (3 nm)/TAPC (40 nm)/TcTa (5 nm)/FCNIrpic (20%): CzSi (30 nm)/TmPyPB (40 nm)/LiF (1 nm)/Al (100 nm) realized the maximum brightness, current efficiency, power efficiency and external quantum efficiency up to 12,505 cd/m{sup 2}, 36.20 cd/A, 28.42 lm/W and 16.9%, respectively. Even at the high brightness of 1000 cd/m{sup 2}, current efficiency and external quantum efficiency up to 17.40 cd/A and 8.1%, respectively, can be retained by the same device.

  4. Extracellular digestion during hyposaline exposure in the Dungeness crab, Cancer magister, and the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Curtis, Daniel L; van Breukelen, Frank; McGaw, Iain J

    2013-12-01

    Extracellular digestive processes were examined in the Dungeness crab, Cancer magister and the blue crab, Callinectes sapidus, during hyposaline exposure. Both species are found in estuaries as adults, but vary in their ability to balance the cardiovascular and respiratory demands of concurrent osmoregulation and digestion. The weak osmoregulator, C. magister, is unable to balance the demands of osmoregulation and digestion. Concordant with observed decreases in oxygen consumption and mechanical digestion, proteolytic digestion within the foregut and hepatopancreas was delayed, resulting in a relative reduction of circulating amino acids post-feeding in low salinity. In contrast, the efficient osmoregulator, C. sapidus, balances the demands of osmoregulation and digestion, and mechanical digestion continues unabated in low salinity. Protease activity in the gut fluid and hepatopancreas showed either no change or a reduction over time. The transport of amino acids into the cells post-feeding is opposed by an efflux of amino acids at the cellular level, and resulted in a build up of amino acids in the hemolymph. Despite differences in the extracellular responses to low salinity exposure following feeding, both species were able to maintain high digestive efficiencies. © 2013.

  5. Near Infrared Photoimmunotherapy with Combined Exposure of External and Interstitial Light Sources.

    Science.gov (United States)

    Maruoka, Yasuhiro; Nagaya, Tadanobu; Sato, Kazuhide; Ogata, Fusa; Okuyama, Shuhei; Choyke, Peter L; Kobayashi, Hisataka

    2018-02-21

    Near infrared photoimmunotherapy (NIR-PIT) is a new target-cell-specific cancer treatment that induces highly selective necrotic/immunogenic cell death after systemic administration of a photoabsorber antibody conjugate and subsequent NIR light exposure. However, the depth of NIR light penetration in tissue (approximately 2 cm) with external light sources limits the therapeutic effects of NIR-PIT. Interstitial light exposure using cylindrical diffusing optical fibers can overcome this limitation. The purpose in this study was to compare three NIR light delivery methods for treating tumors with NIR-PIT using a NIR laser system at an identical light energy; external exposure alone, interstitial exposure alone, and the combination. Panitumumab conjugated with the photoabsorber IRDye-700DX (pan-IR700) was intravenously administered to mice with A431-luc xenografts which are epithelial growth factor receptor (EGFR) positive. One and 2 days later, NIR light was administered to the tumors using one of three methods. Interstitial exposure alone and in combination with external sources showed the greatest decrease in bioluminescence signal intensity. Additionally, the combination of external and interstitial NIR light exposure showed significantly greater tumor size reduction and prolonged survival after NIR-PIT compared to external exposure alone. This result suggested that the combination of external and interstitial NIR light exposure was more effective than externally applied light alone. Although external exposure is the least invasive means of delivering light, the combination of external and interstitial exposures produces superior therapeutic efficacy in tumors greater than 2 cm in depth from the tissue surface.

  6. Carrier Injection and Transport in Blue Phosphorescent Organic Light-Emitting Device with Oxadiazole Host

    Directory of Open Access Journals (Sweden)

    Tien-Lung Chiu

    2012-06-01

    Full Text Available In this paper, we investigate the carrier injection and transport characteristics in iridium(IIIbis[4,6-(di-fluorophenyl-pyridinato-N,C2']picolinate (FIrpic doped phosphorescent organic light-emitting devices (OLEDs with oxadiazole (OXD as the bipolar host material of the emitting layer (EML. When doping Firpic inside the OXD, the driving voltage of OLEDs greatly decreases because FIrpic dopants facilitate electron injection and electron transport from the electron-transporting layer (ETL into the EML. With increasing dopant concentration, the recombination zone shifts toward the anode side, analyzed with electroluminescence (EL spectra. Besides, EL redshifts were also observed with increasing driving voltage, which means the electron mobility is more sensitive to the electric field than the hole mobility. To further investigate carrier injection and transport characteristics, FIrpic was intentionally undoped at different positions inside the EML. When FIrpic was undoped close to the ETL, driving voltage increased significantly which proves the dopant-assisted-electron-injection characteristic in this OLED. When the undoped layer is near the electron blocking layer, the driving voltage is only slightly increased, but the current efficiency is greatly reduced because the main recombination zone was undoped. However, non-negligible FIrpic emission is still observed which means the recombination zone penetrates inside the EML due to certain hole-transporting characteristics of the OXD.

  7. Sleep-Wake Actigraphy and Light Exposure During Spaceflight-Long

    Science.gov (United States)

    Czeisler, Charles A.; Barger, Laura K.; Wright, Kenneth P., Jr.; Ronda, Joseph

    2009-01-01

    Sleep-Wake Actigraphy and Light Exposure During Spaceflight-Long (Sleep-Long) will examine the effects of spaceflight and ambient light exposure on the sleep-wake cycles of the crew members during long-duration stays on the space station.

  8. Ocular effects of chronic exposure to welding light on calabar welders

    African Journals Online (AJOL)

    It was generally observed that welders in Calabar, Nigeria did not always wear their protective goggles during welding. Since chronic exposure to welding light can impair vision this study was done to assess the effect of exposure to welding light on ocular function of welders in Calabar, Nigeria. There were 195 subjects ...

  9. The Progression of Circadian Phase during Light Exposure in Animals and Humans

    NARCIS (Netherlands)

    Beersma, Domien G. M.; Comas, Marian; Hut, Roelof A.; Gordijn, Marijke C. M.; Rueger, Melanie; Daan, Serge

    Studies in humans and mice revealed that circadian phase shifting effects of light are larger at the beginning of a light exposure interval than during subsequent exposure. Little is known about the dynamics of this response reduction phenomenon. Here the authors propose a method to obtain

  10. The influence of bubble populations generated under windy conditions on the blue-green light transmission in the upper ocean: An exploratory approach

    Science.gov (United States)

    Wang, Chengan; Tan, Jianyu; Lai, Qingzhi

    2016-12-01

    The “blue-green window” in the ocean plays an important role in functions such as communication between vessels, underwater target identification, and remote sensing. In this study, the transmission process of blue-green light in the upper ocean is analyzed numerically using the Monte Carlo method. First, the effect of total number of photons on the numerical results is evaluated, and the most favorable number is chosen to ensure accuracy without excessive costs for calculation. Then, the physical and mathematical models are constructed. The rough sea surface is generated under windy conditions and the transmission signals are measured in the far field. Therefore, it can be conceptualized as a 1D slab with a rough boundary surface. Under windy conditions, these bubbles form layers that are horizontally homogeneous and decay exponentially with depth under the influence of gravity. The effects of bubble populations on the process of blue-green light transmission at different wind speeds, wavelengths, angle of incidence and chlorophyll-a concentrations are studied for both air-incident and water-incident cases. The results of this study indicate that the transmission process of blue-green light is significantly influenced by bubbles under high wind-speed conditions.

  11. Bactericidal effect of blue LED light irradiated TiO2/Fe3O4 particles on fish pathogen in seawater

    International Nuclear Information System (INIS)

    Cheng, T.C.; Yao, K.S.; Yeh, N.; Chang, C.I.; Hsu, H.C.; Gonzalez, F.; Chang, C.Y.

    2011-01-01

    This study uses blue LED light (λ max = 475 nm) activated TiO 2 /Fe 3 O 4 particles to evaluate the particles' photocatalytic activity efficiency and bactericidal effects in seawater of variable salinities. Different TiO 2 to Fe 3 O 4 mole ratios have been synthesized using sol-gel method. The synthesized particles contain mainly anatase TiO 2 , Fe 3 O 4 and FeTiO 3 . The study has identified TiO 2 /Fe 3 O 4 's bactericidal effect to marine fish pathogen (Photobacterium damselae subsp. piscicida BCRC17065) in seawater. The SEM photo reveals the surface destruction in bacteria incubated with blue LED irradiated TiO 2 /Fe 3 O 4 . The result of this study indicates that 1) TiO 2 /Fe 3 O 4 acquires photocatalytic activities in both the freshwater and the seawater via blue LED irradiation, 2) higher photocatalytic activities appear in solutions of higher TiO 2 /Fe 3 O 4 mole ratio, and 3) photocatalytic activity decreases as salinity increases. These results suggest that the energy saving blue LED light is a feasible light source to activate TiO 2 /Fe 3 O 4 photocatalytic activities in both freshwater and seawater.

  12. DNA damage in lung after oral exposure to diesel exhaust particles in Big Blue (R) rats

    DEFF Research Database (Denmark)

    Müller, Anne Kirstine; Farombi, E.O.; Møller, P.

    2004-01-01

    Several chemical mutagens and carcinogens, including polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs, are adsorbed to the surface of diesel exhaust particles (DEP). DEP can induce formation of reactive oxygen species and cause oxidative DNA damage as well as bulky carcinogen DNA adducts....... Lung tissue is a target organ for DEP induced cancer following inhalation. Recent studies have provided evidence that the lung is also a target organ for DNA damage and cancer after oral exposure to other complex mixtures of PAHs. The genotoxic effect of oral administration of DEP was investigated...

  13. Effects of blue light-filtering intraocular lenses on the macula, contrast sensitivity, and color vision after a long-term follow-up.

    Science.gov (United States)

    Kara-Junior, Newton; Espindola, Rodrigo F; Gomes, Beatriz A F; Ventura, Bruna; Smadja, David; Santhiago, Marcony R

    2011-12-01

    To evaluate the possible side effects and potential protection 5 years after implantation of an intraocular lens (IOL) with a blue-light filter (yellow tinted). Ophthalmology Department, University of São Paulo, São Paulo, Brazil. Prospective randomized clinical study. Patients with bilateral visually significant cataract randomly received an ultraviolet (UV) and blue light-filtering IOL (Acrysof Natural SN60AT) in 1 eye and an acrylic UV light-filtering only IOL (Acrysof SA60AT) in the fellow eye. The primary outcome measures were contrast sensitivity, color vision, and macular findings 5 years after surgery. The study enrolled 60 eyes of 30 patients. There were no significant clinical or optical coherence tomography findings in terms of age-related macular degeneration in any eye. There were no statistically significant differences in central macular thickness between the 2 IOL groups (P=.712). There were also no significant between-group differences under photopic or scotopic conditions at any spatial frequency studied. No statistically significant differences in the color discrimination test were found between the 2 IOL groups (P=.674). After 5 years, there were no significant differences in color perception, scotopic contrast sensitivity, or photopic contrast sensitivity between the blue light-filtering (yellow-tinted) IOL and the IOL with a UV-light filter only (untinted). The potential advantage of the tinted IOL in providing protection to macular cells remains unclear. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  14. Evidence from Studies with Acifluorfen for Participation of a Flavin-Cytochrome Complex in Blue Light Photoreception for Phototropism of Oat Coleoptiles 12

    Science.gov (United States)

    Leong, Ta-Yan; Briggs, Winslow R.

    1982-01-01

    The diphenyl ether acifluorfen enhances the blue light-induced absorbance change in Triton X100-solubilized crude membrane preparations from etiolated oat (Avena sativa L. cv. Lodi) coleoptiles. Enhancement of the spectral change is correlated with a change in rate of dark reoxidation of a b-type cytochrome. Similar, although smaller, enhancement was obtained with oxyfluorfen, nitrofen, and bifenox. Light-minus-dark difference spectra in the presence and absence of acifluorfen, and the dithionite-reduced-minus oxidized difference spectrum indicate that acifluorfen is acting specifically at a blue light-sensitive cytochrome-flavin complex. Sodium azide, a flavin inhibitor, decreases the light-induced absorbance change significantly, but does not affect the dark reoxidation of the cytochrome. Hence, it is acting on the light reaction, suggesting that the photoreceptor itself is a flavin. Acifluorfen sensitizes phototropism in dark-grown oat seedlings such that the first positive response occurs with blue light fluences as little as one-third of those required to elicit the same response in seedlings grown in the absence of the herbicide. Both this increase in sensitivity to light and the enhancement of the light-induced cytochrome reduction vary with the applied acifluorfen concentration in a similar manner. The herbicide is without effect either on elongation or on the geotropic response of dark-grown oat seedlings, indicating that acifluorfen is acting specifically close to, or at the photoreceptor end of, the stimulus-response chain. It seems likely that the flavin-cytochrome complex serves to transduce the light signal into curvature in phototropism in oats, with the flavin moiety itself serving as the photoreceptor. PMID:16662593

  15. Use of invisible near infrared light fluorescence with indocyanine green and methylene blue in urology. Part 2.

    Science.gov (United States)

    Polom, Wojciech; Markuszewski, Marcin; Rho, Young Soo; Matuszewski, Marcin

    2014-01-01

    In the second part of this paper, concerning the use of invisible near infrared light (NIR) fluorescence with indocyanine green (ICG) and methylene blue (MB) in urology, other possible uses of this new technique will be presented. In kidney transplantation, this concerns allograft perfusion and real time NIR-guided angiography; moreover, perfusion angiography of tissue flaps, NIRF visualization of ureters, NIR-guided visualization of urinary calcifications, NIRF in male infertility and semen quality assessment. In this part, we have also analysed cancer targeting and imaging fluorophores as well as cost benefits associated with the use of these new techniques. PubMed and Medline databases were searched for ICG and MB use in urological settings, along with data published in abstracts of urological conferences. Although NIR-guided ICG and MB are still in their initial phases, there have been significant developments in a few more major domains of urology, including 1) kidney transplantation: kidney allograft perfusion and vessel reconstruction; 2) angiography perfusion of tissue flaps; 3) visualization of ureters; 4) visualization of urinary calcifications; and 5) NIRF in male infertility and semen quality assessment. Near infrared technology in urology is at its early stages. More studies are needed to assess the true potential and limitations of the technology. Initial studies show that this pioneering tool may influence various aspects of urology.

  16. Adjunctive dental therapy via tooth plaque reduction and gingivitis treatment by blue light-emitting diodes tooth brushing

    Science.gov (United States)

    Genina, Elina A.; Titorenko, Vladimir A.; Belikov, Andrey V.; Bashkatov, Alexey N.; Tuchin, Valery V.

    2015-12-01

    The efficacy of blue light-emitting toothbrushes (B-LETBs) (405 to 420 nm, power density 2 mW/cm2) for reduction of dental plaques and gingival inflammation has been evaluated. Microbiological study has shown the multifactor therapeutic action of the B-LETBs on oral pathological microflora: in addition to partial mechanical removal of bacteria, photodynamic action suppresses them up to 97.5%. In the pilot clinical studies, subjects with mild to moderate gingivitis have been randomly divided into two groups: a treatment group that used the B-LETBs and a control group that used standard toothbrushes. Indices of plaque, gingival bleeding, and inflammation have been evaluated. A significant improvement of all dental indices in comparison with the baseline (by 59%, 66%, and 82% for plaque, gingival bleeding, and inflammation, respectively) has been found. The treatment group has demonstrated up to 50% improvement relative to the control group. We have proposed the B-LETBs to serve for prevention of gingivitis or as an alternative to conventional antibiotic treatment of this disease due to their effectiveness and the absence of drug side effects and bacterial resistance.

  17. DISCORDANCE BETWEEN BLUE-LIGHT AUTOFLUORESCENCE AND NEAR-INFRARED AUTOFLUORESCENCE IN AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    Heiferman, Michael J; Fawzi, Amani A

    2016-12-01

    To identify the origin and significance of discordance between blue-light autofluorescence (BL-AF; 488 nm) and near-infrared autofluorescence (NI-AF; 787 nm) in patients with age-related macular degeneration (AMD). A total of 86 eyes of 59 patients with a diagnosis of AMD were included in this cross-sectional study conducted between March 9, 2015 and May 1, 2015. A masked observer examined the BL-AF, NI-AF, and spectral-domain optical coherence tomography images. Areas with discordance of autofluorescence patterns between NI-AF and BL-AF images were correlated with structural findings at the corresponding location in optical coherence tomography scans. Seventy-nine eyes had discordance between BL-AF and NI-AF. The most common optical coherence tomography finding accounting for these discrepancies was pigment migration accounting for 35 lesions in 21 eyes. The most clinically relevant finding was geographic atrophy missed on BL-AF in 7 eyes. Our findings indicate that variations in the distribution of lipofuscin, melanin and melanolipofuscin account for the majority of discordance between BL-AF and NI-AF. Given our finding of missed geographic atrophy lesions on BL-AF in 24% of eyes with geographic atrophy (7/29 eyes), clinicians should consider multimodal imaging, including NI-AF and optical coherence tomography, especially in clinical trials of geographic atrophy.

  18. Comparison of collimated blue-light generation in 85Rb atoms via the D1 and D2 lines

    Science.gov (United States)

    Prajapati, Nikunj; Akulshin, Alexander M.; Novikova, Irina

    2018-05-01

    We experimentally studied the characteristics of the collimated blue light (CBL) produced in ${}^{85}$Rb vapor by two resonant laser fields exciting atoms into the $5D_{3/2}$ state, using either the $5P_{1/2}$ or the $5P_{3/2}$ intermediate state. We compared the CBL output at different values of frequency detunings, powers, and polarizations of the pump lasers in these two cases, and confirmed the observed trends using a simple theoretical model. We also demonstrated that the addition of the repump laser, preventing the accumulation of atomic population in the uncoupled hyperfine ground state, resulted in nearly an order of magnitude increase in CBL power output. Overall, we found that the $5S_{1/2} - 5P_{1/2} - 5D_{3/2}$ excitation pathway results in stronger CBL generation, as we detected up to $4.25~\\mu$W using two pumps of the same linear polarization. The optimum CBL output for the $5S_{1/2} - 5P_{3/2} - 5D_{3/2}$ excitation pathway required the two pump lasers to have the same circular polarization, but resulted only in a maximum CBL power of $450$~nW.

  19. The effect of a charge control layer on the electroluminescent characteristic of blue and white organic light-emitting diodes.

    Science.gov (United States)

    Lee, Dong Hyung; Lee, Seok Jae; Koo, Ja-Ryong; Lee, Ho Won; Shin, Hyun Su; Lee, Song Eun; Kim, Woo Young; Lee, Kum Hee; Yoon, Seung Soo; Kim, Young Kwan

    2014-08-01

    We investigated blue fluorescent organic light-emitting diode (OLED) with a charge control layer (CCL) to produce high efficiency and improve the half-decay lifetime. Three types of devices (device A, B, and C) were fabricated following the number of CCLs within the emitting layer (EML), maintaining the thickness of whole EML. The CCL and host material, 2-methyl-9,10-di(2-naphthyl)anthracene, which has a bipolar property, was able to control the carrier movement with ease inside the EML. Device B demonstrated a maximum luminous efficiency (LE) and external quantum efficiency (EQE) of 9.19 cd/A and 5.78%, respectively. It also showed that the enhancement of the half-decay lifetime, measured at an initial luminance of 1,000 cd/m2, was 1.5 times longer than that of the conventional structure. A hybrid white OLED (WOLED) was also fabricated using a phosphorescent red emitter, bis(2-phenylquinoline)-acetylacetonate iridium III doped in 4,4'-N,N'-dicarbazolyl-biphenyl. The property of the hybrid WOLED with CCL showed a maximum LE and an EQE of 13.46 cd/A and 8.32%, respectively. It also showed white emission with Commission International de L'Éclairage coordinates of (x = 0.41, y = 0.33) at 10 V.

  20. Auger-generated hot carrier current in photo-excited forward biased single quantum well blue light emitting diodes

    Science.gov (United States)

    Espenlaub, Andrew C.; Alhassan, Abdullah I.; Nakamura, Shuji; Weisbuch, Claude; Speck, James S.

    2018-04-01

    We report on measurements of the photo-modulated current-voltage and electroluminescence characteristics of forward biased single quantum well, blue InGaN/GaN light emitting diodes with and without electron blocking layers. Low intensity resonant optical excitation of the quantum well was observed to induce an additional forward current at constant forward diode bias, in contrast to the usual sense of the photocurrent in photodiodes and solar cells, as well as an increased electroluminescence intensity. The presence of an electron blocking layer only slightly decreased the magnitude of the photo-induced current at constant forward bias. Photo-modulation at constant forward diode current resulted in a reduced diode bias under optical excitation. We argue that this decrease in diode bias at constant current and the increase in forward diode current at constant applied bias can only be due to additional hot carriers being ejected from the quantum well as a result of an increased Auger recombination rate within the quantum well.

  1. Dengue and chikungunya viruses in plasma are effectively inactivated after treatment with methylene blue and visible light.

    Science.gov (United States)

    Fryk, Jesse J; Marks, Denese C; Hobson-Peters, Jody; Prow, Natalie A; Watterson, Daniel; Hall, Roy A; Young, Paul R; Reichenberg, Stefan; Sumian, Chryslain; Faddy, Helen M

    2016-09-01

    Arboviruses, such as dengue viruses (DENV) and chikungunya virus (CHIKV), pose a risk to the safe transfusion of blood components, including plasma. Pathogen inactivation is an approach to manage this transfusion transmission risk, with a number of techniques being used worldwide for the treatment of plasma. In this study, the efficacy of the THERAFLEX MB-Plasma system to inactivate all DENV serotypes (DENV-1, DENV-2, DENV-3, DENV-4) or CHIKV in plasma, using methylene blue and light illumination at 630 nm, was investigated. Pooled plasma units were spiked with DENV-1, DENV-2, DENV-3 DENV-4, or CHIKV and treated with the THERAFLEX MB-Plasma system at four light illumination doses: 20, 40, 60, and 120 (standard dose) J/cm(2) . Pre- and posttreatment samples were collected and viral infectivity was determined. The reduction in viral infectivity was calculated for each dose. Treatment of plasma with the THERAFLEX MB-Plasma system resulted in at least a 4.46-log reduction in all DENV serotypes and CHIKV infectious virus. The residual infectivity for each was at the detection limit of the assay used at 60 J/cm(2) , with dose dependency also observed. Our study demonstrated the THERAFLEX MB-Plasma system can reduce the infectivity of all DENV serotypes and CHIKV spiked into plasma to the detection limit of the assay used at half of the standard illumination dose. This suggests this system has the capacity to be an effective option for managing the risk of DENV or CHIKV transfusion transmission in plasma. © 2016 AABB.

  2. Photocatalytic degradation of methylene blue on magnetically separable MgFe2O4 under visible light irradiation

    International Nuclear Information System (INIS)

    Shahid, Muhammad; Jingling, Liu; Ali, Zahid; Shakir, Imran; Warsi, Muhammad Farooq; Parveen, Riffat; Nadeem, Muhammad

    2013-01-01

    A magnetically separable single-phase MgFe 2 O 4 photocatalyst with a spinel crystal structure was synthesized by using the solid-state reaction method. The formation of spinel structure is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic measurements showed that the photocatalyst material can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for waste water treatment. The photocatalytic activity of MgFe 2 O 4 was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe 2 O 4 was studied by measuring their photocurrent–potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm −2 illumination. - Graphical abstract: Highly efficient magnetically separable MgFe 2 O 4 photocatalyst for organic based impurities decomposition as well as for the production of H 2 gas was synthesized and characterized successfully (a) MgFe 2 O 4 photocatalyst in polluted water, (b) The photocatalyst (MgFe 2 O 4 ) is being attracted toward magnetic field for separation, (c) Hysteresis loop of MgFe 2 O 4 showing magnetic behavior. Highlights: ► New photocatalyst working in the visible range have been synthesized by facile cheap route. ► MgFe 2 O 4 photocatalyst showed well defined magnetically separable behavior. ► Excellent water splitting characteristics to produce H 2 was observed under visible light irradiation

  3. Exposure to Visible Light Emitted from Smartphones and Tablets Increases the Proliferation of Staphylococcus aureus: Can this be Linked to Acne?

    Directory of Open Access Journals (Sweden)

    Taheri M.

    2017-06-01

    Full Text Available Background: Due to rapid advances in modern technologies such as telecommunication technology, the world has witnessed an exponential growth in the use of digital handheld devices (e.g. smartphones and tablets. This drastic growth has resulted in increased global concerns about the safety of these devices. Smartphones, tablets, laptops, and other digital screens emit high levels of short-wavelength visible light (i.e. blue color region in the visible light spectrum. Material and Methods: At a dark environment, Staphylococcus aureus bacteria were exposed to the light emitted from common tablets/smartphones. The control samples were exposed to the same intensity of light generated by a conventional incandescent light bulb. The growth rate of bacteria was examined by measuring the optical density (OD at 625 nm by using a spectrophotometer before the light exposure and after 30 to 330 minutes of light exposure. Results: The growth rates of bacteria in both smartphone and tablet groups were higher than that of the control group and the maximum smartphone/control and tablet/control growth ratios were observed in samples exposed to digital screens’ light for 300 min (ratios of 3.71 and 3.95, respectively. Conclusion: To the best of our knowledge, this is the first study that investigates the effect of exposure to light emitted from digital screens on the proliferation of Staphylococcus aureus and its association with acne pathogenesis. Our findings show that exposure to short-wavelength visible light emitted from smartphones and tablets can increase the proliferation of Staphylococcus aureus.

  4. Exposure to Visible Light Emitted from Smartphones and Tablets Increases the Proliferation of Staphylococcus aureus: Can this be Linked to Acne?

    Science.gov (United States)

    Taheri, M.; Darabyan, M.; Izadbakhsh, E.; Nouri, F.; Haghani, M.; Mortazavi, S.A.R.; Mortazavi, G.; Mortazavi, S.M.J.; Moradi, M.

    2017-01-01

    Background: Due to rapid advances in modern technologies such as telecommunication technology, the world has witnessed an exponential growth in the use of digital handheld devices (e.g. smartphones and tablets). This drastic growth has resulted in increased global concerns about the safety of these devices. Smartphones, tablets, laptops, and other digital screens emit high levels of short-wavelength visible light (i.e. blue color region in the visible light spectrum). Material and Methods: At a dark environment, Staphylococcus aureus bacteria were exposed to the light emitted from common tablets/smartphones. The control samples were exposed to the same intensity of light generated by a conventional incandescent light bulb. The growth rate of bacteria was examined by measuring the optical density (OD) at 625 nm by using a spectrophotometer before the light exposure and after 30 to 330 minutes of light exposure. Results: The growth rates of bacteria in both smartphone and tablet groups were higher than that of the control group and the maximum smartphone/control and tablet/control growth ratios were observed in samples exposed to digital screens’ light for 300 min (ratios of 3.71 and 3.95, respectively). Conclusion: To the best of our knowledge, this is the first study that investigates the effect of exposure to light emitted from digital screens on the proliferation of Staphylococcus aureus and its association with acne pathogenesis. Our findings show that exposure to short-wavelength visible light emitted from smartphones and tablets can increase the proliferation of Staphylococcus aureus. PMID:28580338

  5. Light Exposure Assessment of Danish Indoor, outdoor and Night-Shift Workers

    DEFF Research Database (Denmark)

    Markvart, Jakob

    2017-01-01

    A research talk about: • The Lux@r project - The context of this talk • Light and light exposure - What When and Where • Light as a “one-dimensional unit” – things that matters: 1. Spectral sensitivity 2. Spatial sensitivity...

  6. Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study).

    Science.gov (United States)

    Ichikawa, Kazuo

    2014-07-01

    Blood pressure and sleep duration may be influenced by retinal light exposure. Cataracts may exert such an influence by decreasing the transparency of the crystalline lens. A large-scale clinical study was conducted to examine changes in blood pressure and sleep duration after intraocular lens (IOL) implantation during cataract surgery and to investigate how different types of IOL influence the degree of these effects. Using a questionnaire, we collected information, including blood pressure measurement and sleep duration, from 1367 patients (1367 eyes) before IOL implantation, 1 week after IOL implantation and 1 month after IOL implantation. Systolic and diastolic blood pressures were significantly decreased in the total patient group after implantation. The decrease in systolic blood pressure 1 month after implantation was significantly more in patients who received a yellow-tinted IOL than it was in those who received an ultraviolet (UV) light-filtering IOL. The post-implantation sleep duration, including naps, became shorter in patients who had slept too much and became longer in those who had slept too little before IOL implantation. Our observations suggest that a yellow-tinted IOL is better for patients with high blood pressure than a UV light-filtering IOL. Furthermore, the yellow-tinted IOL is as good as the UV light-filtering IOL for improving sleep duration. A pale yellow-tinted IOL is likely to be superior to a moderate yellow-tinted IOL in terms of allowing patients to discriminate different colors. Thus, the pale yellow-tinted IOL appears to be better for patients than the UV light-filtering IOL and the moderate yellow-tinted IOL.

  7. Reduction of Zika virus infectivity in platelet concentrates after treatment with ultraviolet C light and in plasma after treatment with methylene blue and visible light.

    Science.gov (United States)

    Fryk, Jesse J; Marks, Denese C; Hobson-Peters, Jody; Watterson, Daniel; Hall, Roy A; Young, Paul R; Reichenberg, Stefan; Tolksdorf, Frank; Sumian, Chryslain; Gravemann, Ute; Seltsam, Axel; Faddy, Helen M

    2017-11-01

    Zika virus (ZIKV) has emerged as a potential threat to transfusion safety worldwide. Pathogen inactivation is one approach to manage this risk. In this study, the efficacy of the THERAFLEX UV-Platelets system and THERAFLEX MB-Plasma system to inactivate ZIKV in platelet concentrates (PCs) and plasma was investigated. PCs spiked with ZIKV were treated with the THERAFLEX UV-Platelets system at 0.05, 0.10, 0.15, and 0.20 J/cm 2 UVC. Plasma spiked with ZIKV was treated with the THERAFLEX MB-Plasma system at 20, 40, 60, and 120 J/cm 2 light at 630 nm with at least 0.8 µmol/L methylene blue (MB). Samples were taken before the first and after each illumination dose and tested for residual virus. For each system the level of viral reduction was determined. Treatment of PCs with THERAFLEX UV-Platelets system resulted in a mean of 5 log reduction in ZIKV infectivity at the standard UVC dose (0.20 J/cm 2 ), with dose dependency observed with increasing UVC dose. For plasma treated with MB and visible light, ZIKV infectivity was reduced by a mean of at least 5.68 log, with residual viral infectivity reaching the detection limit of the assay at 40 J/cm 2 (one-third the standard dose). Our study demonstrates that the THERAFLEX UV-Platelets system and THERAFLEX MB-Plasma system can reduce ZIKV infectivity in PCs and pooled plasma to the detection limit of the assays used. These findings suggest both systems have the capacity to be an effective option to manage potential ZIKV transfusion transmission risk. © 2017 AABB.

  8. Blue Light-excited Light-Oxygen-Voltage-sensing Domain 2 (LOV2) Triggers a Rearrangement of the Kinase Domain to Induce Phosphorylation Activity in Arabidopsis Phototropin1.

    Science.gov (United States)

    Oide, Mao; Okajima, Koji; Kashojiya, Sachiko; Takayama, Yuki; Oroguchi, Tomotaka; Hikima, Takaaki; Yamamoto, Masaki; Nakasako, Masayoshi

    2016-09-16

    Phototropin1 is a blue light (BL) receptor in plants and shows BL-dependent kinase activation. The BL-excited light-oxygen-voltage-sensing domain 2 (LOV2) is primarily responsible for the activation of the kinase domain; however, the molecular mechanism by which conformational changes in LOV2 are transmitted to the kinase domain remains unclear. Here, we investigated BL-induced structural changes of a minimum functional fragment of Arabidopsis phototropin1 composed of LOV2, the kinase domain, and a linker connecting the two domains using small-angle x-ray scattering (SAXS). The fragment existed as a dimer and displayed photoreversible SAXS changes reflected in the radii of gyration of 42.9 Å in the dark and 48.8 Å under BL irradiation. In the dark, the molecular shape reconstructed from the SAXS profiles appeared as two bean-shaped lobes in a twisted arrangement that was 170 Å long, 80 Å wide, and 50 Å thick. The molecular shape under BL became slightly elongated from that in the dark. By fitting the crystal structure of the LOV2 dimer and a homology model of the kinase domain to their inferred shapes, the BL-dependent change could be interpreted as the positional shift in the kinase domain relative to that of the LOV2 dimer. In addition, we found that lysine 475, a functionally important residue, in the N-terminal region of LOV2 plays a critical role in transmitting the structural changes in LOV2 to the kinase domain. The interface between the domains is critical for signaling, suitably changing the structure to activate the kinase in response to conformational changes in the adjoining LOV2. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Synthesis and electroluminescent properties of blue emitting materials based on arylamine-substituted diphenylvinylbiphenyl derivatives for organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kum Hee; You, Jae Nam; Won, Jiyeon; Lee, Jin Yong [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Seo, Ji Hoon [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@hongik.ac.kr [Department of Information Display, Hongik University, Seoul, 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2011-10-31

    This paper reports the synthesis and electroluminescent properties of a series of blue emitting materials with arylamine and diphenylvinylbiphenyl groups for applications to efficient blue organic light-emitting diodes (OLEDs). All devices exhibited blue electroluminescence with electroluminescent properties that were quite sensitive to the structural features of the dopants in the emitting layers. In particular, the device using dopant 4 exhibited sky-blue emission with a maximum luminance, luminance efficiency, power efficiency, external quantum efficiency and CIE coordinates of 39,000 cd/m{sup 2}, 12.3 cd/A, 7.45 lm/W, 7.71% at 20 mA/cm{sup 2} and (x = 0.17, y = 0.31) at 8 V, respectively. In addition, a blue OLED using dopant 2 with CIE coordinates (x = 0.16, y = 0.18) at 8 V exhibited a luminous efficiency, power efficiency and external quantum efficiency of 4.39 cd/A, 2.46 lm/W and 2.97% at 20 mA/cm{sup 2}, respectively.

  10. FAKE STAR FORMATION BURSTS: BLUE HORIZONTAL BRANCH STARS MASQUERADE AS YOUNG MASSIVE STARS IN OPTICAL INTEGRATED LIGHT SPECTROSCOPY

    International Nuclear Information System (INIS)

    Ocvirk, P.

    2010-01-01

    Model color-magnitude diagrams of low-metallicity globular clusters (GCs) usually show a deficit of hot evolved stars with respect to observations. We investigate quantitatively the impact of such modeling inaccuracies on the significance of star formation history reconstructions obtained from optical integrated spectra. To do so, we analyze the sample of spectra of galactic globular clusters of Schiavon et al. with STECKMAP (Ocvirk et al.), and the stellar population models of Vazdekis et al. and Bruzual and Charlot, and focus on the reconstructed stellar age distributions. First, we show that background/foreground contamination correlates with E(B - V), which allows us to define a clean subsample of uncontaminated GCs, on the basis of an E(B - V) filtering. We then identify a 'confusion zone' where fake young bursts of star formation pop up in the star formation history although the observed population is genuinely old. These artifacts appear for 70%-100% of cases depending on the population model used, and contribute up to 12% of the light in the optical. Their correlation with the horizontal branch (HB) ratio indicates that the confusion is driven by HB morphology: red HB clusters are well fitted by old stellar population models while those with a blue HB require an additional hot component. The confusion zone extends over [Fe/H] = [ - 2, - 1.2], although we lack the data to probe extreme high and low metallicity regimes. As a consequence, any young starburst superimposed on an old stellar population in this metallicity range could be regarded as a modeling artifact, if it weighs less than 12% of the optical light, and if no emission lines typical of an H II region are present. This work also provides a practical method for constraining HB morphology from high signal to noise integrated light spectroscopy in the optical. This will allow post-asymptotic giant branch evolution studies in a range of environments and at distances where resolving stellar populations

  11. Manipulation of Thermally Activated Delayed Fluorescence of Blue Exciplex Emission: Fully Utilizing Exciton Energy for Highly Efficient Organic Light Emitting Diodes with Low Roll-Off.

    Science.gov (United States)

    Wang, Zixing; Wang, Hedan; Zhu, Jun; Wu, Peng; Shen, Bowen; Dou, Dehai; Wei, Bin

    2017-06-28

    The application of exciplex energy has become a unique way to achieve organic light-emitting diodes (OLEDs) with high efficiencies, low turn-on voltage, and low roll-off. Novel δ-carboline derivatives with high triplet energy (T 1 ≈ 2.92 eV) and high glass transition temperature (T g ≈ 153 °C) were employed to manipulate exciplex emissions in this paper. Deep blue (peak at 436 nm) and pure blue (peak at 468 nm) thermally activated delayed fluorescence (TADF) of exciplex OLEDs were demonstrated by utilizing them as emitters with the maximum current efficiency (CE) of 4.64 cd A -1 , power efficiency (PE) of 2.91 lm W -1 , and external quantum efficiency (EQE) of 2.36%. Highly efficient blue phosphorescent OLEDs doped with FIrpic showed a maximum CE of 55.6 cd A -1 , PE of 52.9 lm W -1 , and EQE of 24.6% respectively with very low turn on voltage at 2.7 V. The devices still remain high CE of 46.5 cd A -1 at 100 cd m -2 , 45.4 cd A -1 at 1000 cd m -2 and 42.3 cd A -1 at 5000 cd m -2 with EQE close to 20% indicating low roll-off. Manipulating blue exciplex emissions by chemical structure gives an ideal strategy to fully utilize all exciton energies for lighting of OLEDs.

  12. Do wild great tits avoid exposure to light at night?

    NARCIS (Netherlands)

    De Jong, M.; Ouyang, Jenny; van Grunsven, Roy H. A.; Visser, M.E.; Spoelstra, K.

    2016-01-01

    Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their

  13. Do wild great tits avoid exposure to light at night?

    NARCIS (Netherlands)

    Jong, De Maaike; Ouyang, Jenny Q.; Grunsven, van Roy H.A.; Visser, Marcel E.; Spoelstra, Kamiel

    2016-01-01

    Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their

  14. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    Science.gov (United States)

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. © 2014 John Wiley & Sons Ltd.

  15. Sonophotocatalytic degradation of trypan blue and vesuvine dyes in the presence of blue light active photocatalyst of Ag3PO4/Bi2S3-HKUST-1-MOF: Central composite optimization and synergistic effect study.

    Science.gov (United States)

    Mosleh, S; Rahimi, M R; Ghaedi, M; Dashtian, K

    2016-09-01

    An efficient simultaneous sonophotocatalytic degradation of trypan blue (TB) and vesuvine (VS) using Ag3PO4/Bi2S3-HKUST-1-MOF as a novel visible light active photocatalyst was carried out successfully in a continuous flow-loop reactor equipped to blue LED light. Ag3PO4/Bi2S3-HKUST-1-MOF with activation ability under blue light illumination was synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), photoluminescence (PL) and diffuse reflectance spectra (DRS). The effect of operational parameters such as the initial TB and VS concentration (5-45mg/L), flow rate (30-110mL/min), irradiation and sonication time (10-30min), pH (3-11) and photocatalyst dosage (0.15-0.35g/L) has been investigated and optimized using central composite design (CCD) combined with desirability function (DF). Maximum sonophotodegradation percentage (98.44% and 99.36% for TB and VS, respectively) was found at optimum condition set as: 25mg/L of each dye, 70mL/min of solution flow rate, 25min of irradiation and sonication time, pH 6 and 0.25g/L of photocatalyst dosage. At optimum conditions, synergistic index value was obtained 2.53 that indicated the hybrid systems including ultrasound irradiation and photocatalysis have higher efficiency compared with sum of the individual processes. Copyright © 2016. Published by Elsevier B.V.

  16. White organic light-emitting devices based on blue fluorescent dye combined with dual sub-monolayer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huishan, E-mail: yanghuishan1697@163.com

    2013-10-15

    White organic light-emitting devices have been realized by using highly blue fluorescent dye 4,4′-Bis(2,2-diphenyl-ethen-1-yl)-4,4′-di-(tert-butyl)phenyl(p-TDPVBi) and [2-methyl-6-[2-(2, 3,6,7-tetrahydro-1H, red fluorescent dye 5H-benzo[ij] quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene] propane-dinitrile(DCM2), together with well known green fluorescent dye quinacridone (QAD). The fabrication of multilayer WOLEDs did not involve the hard-to-control doping process. The structure of the device is ITO/m-MTDATA (45 nm)/NPB(8 nm)/p-TDPVBi(15 nm)/DCM2(x nm)/Alq{sub 3} (5 nm)/QAD(y nm)/Alq{sub 3}(55 nm)/LiF(1 nm)/Al, where 4,4′,4′′-tris{N,-(3-methylphenyl)-N-phenylamine}triphenylamine (m-MTDATA) acts as a hole injection layer, N,N′-bis-(1-naphthyl)-N, N′-diphenyl-1, 1′-biph-enyl-4, 4′-diamine (NPB) acts as a hole transport layer, p-TDPVBi acts as a blue emitting layer, DCM2 acts as a red emitting layer, QAD acts as a green emitting layer, tris-(8-hydroxyquinoline) aluminum (Alq{sub 3}) acts as an electron transport layer, and WOLEDs of devices A, B, C and D are different in layer thickness of DCM2 and QAD, respectively. To change the thickness of dual sub-monolayer DCM2 and QAD, the WOLEDs were obtained. When x, y=0.05, 0.1, the Commission Internationale de 1’Eclairage (CIE) coordinates of the device change from (0.4458, 0.4589) at 3 V to (0.3137, 0.3455) at 12 V that are well in the white region, and the color temperature and color rendering index were 5348 K and 85 at 8 V, respectively. Its maximum luminance was 35260 cd/m{sup 2} at 12 V, and maximum current efficiency and maximum power efficiency were 13.54 cd/A at 12 V and 6.68 lm/W at 5 V, respectively. Moreover, the current efficiency is largely insensitive to the applied voltage. The electroluminescence intensity of white EL devices varied only little at deferent dual sub-monolayer. Device D exhibited relatively high color rendering index (CRI) in the range of 88–90, which was essentially

  17. Remanagement of Singlet and Triplet Excitons in Single-Emissive-Layer Hybrid White Organic Light-Emitting Devices Using Thermally Activated Delayed Fluorescent Blue Exciplex.

    Science.gov (United States)

    Liu, Xiao-Ke; Chen, Zhan; Qing, Jian; Zhang, Wen-Jun; Wu, Bo; Tam, Hoi Lam; Zhu, Furong; Zhang, Xiao-Hong; Lee, Chun-Sing

    2015-11-25

    A high-performance hybrid white organic light-emitting device (WOLED) is demonstrated based on an efficient novel thermally activated delayed fluorescence (TADF) blue exciplex system. This device shows a low turn-on voltage of 2.5 V and maximum forward-viewing external quantum efficiency of 25.5%, which opens a new avenue for achieving high-performance hybrid WOLEDs with simple structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Solution processed multilayer red, green and blue phosphorescent organic light emitting diodes using carbazole dendrimer as a host

    International Nuclear Information System (INIS)

    Hasan, Zainal Abidin; Woon, Kai Lin; Wong, Wah Seng; Ariffin, Azhar; Chen, Show-An

    2017-01-01

    4, 4'-bis(3,6-bis(3, 6-ditert-pentyl-carbazol-9-yl)carbazol-9-yl)-2,2'-dimethylbiphenyl, a novel carbazole dendrimer, has been synthesized. This compound shows an excellent thermal stability with a high glass transition temperature of 283 °C and decomposition temperature of 487 °C. Density functional theory is used to investigate the frontier orbitals. It was found that the Highest Occupied Molecular Orbital and the Lowest Unoccupied Molecular Orbital levels of 4, 4'-bis(3,6-bis(3, 6-ditert-pentyl-carbazol-9-yl)carbazol-9-yl)-2,2'-dimethylbiphenyl are nearly degenerate to the next highest or lowest frontier orbitals. The electron rich outer dendrons along with Highest Occupied Molecular Orbital level of 5.24 eV as determined from cyclic voltammetry makes 4, 4'-bis(3,6-bis(3,6-ditert-pentyl-carbazol-9-yl)carbazol-9-yl)-2, 2'-dimethylbiphenyl a good hole transporting material. This compound also shows a triplet energy of 2.83 eV. Solution processable multilayer red, green and blue phosphorescent organic light emitting diodes are fabricated having 4, 4'-bis(3,6-bis(3,6-ditert-pentyl-carbazol-9-yl) carbazol-9-yl)-2,2'-dimethylbiphenyl as a hole transporting host. It was found that the CIE-coordinates remain constant within a wide range of brightness.

  19. Photophysical study of blue-light excitable ternary Eu(III) complexes and their encapsulation into polystyrene nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Räsänen, Markus, E-mail: mpvras@utu.fi [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland); Takalo, Harri [DHR Finland Oy, Innotrac Diagnostics, Biolinja 12, FIN-20750 Turku (Finland); Soukka, Tero [Department of Biochemistry/Biotechnology, University of Turku, FIN-20014 Turku (Finland); Haapakka, Keijo; Kankare, Jouko [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland)

    2015-04-15

    In this work, 14 ternary Eu(III) complexes were studied by means of spectroscopy. The studied Eu(III) complexes consisted of Lewis bases (4′-(4-diethylaminophenyl)-2,2′:6′,2″-terpyridine (L{sup 8}) or 1,10-phenanthroline (L{sup 9})) and differently substituted β-diketones. The ternary complexes with L{sup 8} show the excitation peak at 405 nm and the quantum yield even 76%. The brightest ternary complex at the 405 nm excitation was Eu(L{sup 3}){sub 3}L{sup 8} while Eu(L{sup 7}){sub 3}L{sup 8} (HL{sup 3}=4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione, HL{sup 7}=1-(9-ethyl-9H-carbazol-3-yl)-4,4,5,5,5-pentafluoro-1,3-pentanedione) was found to be the brightest at the ligand-centred excitation maximum. The ternary complexes were studied mainly in toluene as the model environment for the polystyrene nanoparticle cavities. The complexes were successfully loaded into the polystyrene nanoparticles enabling their bioanalytical application in aqueous environment. The encapsulation of the complexes preserved, or even enhanced, their good photophysical features. - Highlights: • Ternary Eu{sup 3+} complexes with some β-diketone and substituted terpyridine were studied. • Ternary complexes with substituted terpyridine showed blue-light excitability. • Ternary complexes were successfully loaded into the polystyrene nanoparticles. • Encapsulation of the complexes preserved their good photophysical features.

  20. Effects of the cryptochrome CryB from Rhodobacter sphaeroides on global gene expression in the dark or blue light or in the presence of singlet oxygen.

    Directory of Open Access Journals (Sweden)

    Sebastian Frühwirth

    Full Text Available Several regulators are controlling the formation of the photosynthetic apparatus in the facultatively photosynthetic bacterium Rhodobacter sphaeroides. Among the proteins affecting photosynthesis gene expression is the blue light photoreceptor cryptochrome CryB. This study addresses the effect of CryB on global gene expression. The data reveal that CryB does not only influence photosynthesis gene expression but also genes for the non-photosynthetic energy metabolism like citric acid cycle and oxidative phosphorylation. In addition several genes involved in RNA processing and in transcriptional regulation are affected by a cryB deletion. Although CryB was shown to undergo a photocycle it does not only affect gene expression in response to blue light illumination but also in response to singlet oxygen stress conditions. While there is a large overlap in these responses, some CryB-dependent effects are specific for blue-light or photooxidative stress. In addition to protein-coding genes some genes for sRNAs show CryB-dependent expression. These findings give new insight into the function of bacterial cryptochromes and demonstrate for the first time a function in the oxidative stress response.

  1. Characterization of a rapid, blue light-mediated change in detectable phosphorylation of a plasma membrane protein from etiolated pea (Pisum sativum L.) seedlings

    International Nuclear Information System (INIS)

    Short, T.W.; Briggs, W.R.

    1990-01-01

    When crude microsomal membranes from apical stem segments of etiolated Pisum sativum L. cv Alaska are mixed in vitro with γ-[ 32 P]ATP, a phosphorylated band of apparent molecular mass 120 kilodaltons can be detected on autoradiographs of sodium dodecyl sulfate electrophoresis gels. If the stem sections are exposed to blue light immediately prior to membrane isolation, this band is not evident. Comparisons of the kinetics, tissue distribution, and dark recovery of the phosphorylation response with those published for blue light mediated phototropism or rapid growth inhibition indicate that the phosphorylation could be linked to one or both of the reactions described. However, the fluence-response relationships for the change in detectable phosphorylation match quite closely those reported for phototropism but not those for growth inhibition. Blue light has also been found to regulate the capacity for in vitro phosphorylation of a second protein. It has an apparent molecular mass of 84 kilodaltons and is localized primarily in basal stem sections

  2. Prenatal radiation exposure. Conclusions in the light of radiology

    International Nuclear Information System (INIS)

    Leppin, W.

    1987-01-01

    Within 6 years of the appearance of the guideline for action to be taken by doctors in the event of prenatal exposure to radiation, intended as a proposal for discussion, the following has turned out: in no case has termination of pregnancy become necessary following prenatal radiation exposure, prenatal radiation exposure was always low (about 20 mSv), there is no risk below respective threshold doses, teratogenesis is a non-stochastic process, which is why risk assessment was modified, the sensitivity of the human fetus to radiation is highest during the period of neuroblast development (9th to 16th week p.c.), and knowledge about an existing pregnancy can be taken for granted by that time, so radiation exposure is calculable and can be restricted to negligible quantities. (TRV) [de

  3. Transfer from blue light or green light to white light partially reverses changes in ocular refraction and anatomy of developing guinea pigs.

    Science.gov (United States)

    Qian, Yi-Feng; Liu, Rui; Dai, Jin-Hui; Chen, Min-Jie; Zhou, Xing-Tao; Chu, Ren-Yuan

    2013-09-26

    Relative to the broadband white light (BL), postnatal guinea pigs develop myopia in a monochromic middle-wavelength light (ML, 530 nm) environment and develop hyperopia in a monochromic short-wavelength light (SL, 430 nm) environment. We investigated whether transfer from SL or ML to BL leads to recuperation of ocular refraction and anatomy of developing guinea pigs. Two-week-old guinea pigs were given (a) SL for 20 weeks, (b) SL recuperation (SLR, SL for 10 weeks then BL for 10 weeks), (c) ML for 20 weeks, (d) ML recuperation (MLR, ML for 10 weeks then BL for 10 weeks), or (e) BL for 20 weeks. Two weeks after transfer from ML to BL (MLR group), ocular refraction increased from 1.95 ± 0.35 D to 2.58 ± 0.24 D, and vitreous length decreased from 3.48 ± 0.06 mm to 3.41 ± 0.06 mm. Two weeks after transfer from SL to BL (SLR group), ocular refraction decreased from 5.65 ± 0.61 D to 4.33 ± 0.49 D, and vitreous length increased from 3.18 ± 0.07 mm to 3.26 ± 0.11 mm. The MLR and SLR groups had final ocular refractions that were significantly different from those of the ML and SL groups at 20 weeks (ML vs. MLR: p < 0.0001; SL vs. SLR: p < 0.0001) but were still significantly different from the BL group (BL vs. MLR: p = 0.0120; BL vs. SLR: p = 0.0010). These results suggest that recuperation was not complete after return to BL for 10 weeks.

  4. Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study

    Directory of Open Access Journals (Sweden)

    Lameese D. Akacem

    2016-11-01

    Full Text Available Light exposure and sleep timing are two factors that influence inter-individual variability in the timing of the human circadian clock. The aim of this study was to quantify the degree to which evening light exposure predicts variance in circadian timing over and above bedtime alone in preschool children. Participants were 21 children ages 4.5–5.0 years (4.7±0.2 years; 9 females. Children followed their typical sleep schedules for 4 days during which time they wore a wrist actigraph to assess sleep timing and a pendant light meter to measure minute-by-minute illuminance levels in lux. On the 5th day, children participated in an in-home dim-light melatonin onset (DLMO assessment. Light exposure in the 2 h before bedtime was averaged and aggregated across the 4 nights preceding the DLMO assessment. Mean DLMO and bedtime were 19:22±01:04 and 20:07±00:46, respectively. Average evening light exposure was 710.1±1418.2 lux. Children with later bedtimes (lights-off time had more delayed melatonin onset times (r=0.61, p=0.002. Evening light exposure was not independently associated with DLMO (r=0.32, p=0.08; however, a partial correlation between evening light exposure and DLMO when controlling for bedtime yielded a positive correlation (r=0.46, p=0.02. Bedtime explained 37.3% of the variance in the timing of DLMO, and evening light exposure accounted for an additional 13.3% of the variance. These findings represent an important step in understanding factors that influence circadian phase in preschool-age children and have implications for understanding a modifiable pathway that may underlie late sleep timing and the development of evening settling problems in early childhood.

  5. Single-frequency blue light generation by single-pass sum-frequency generation in a coupled ring cavity tapered laser

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    A generic approach for generation of tunable single frequency light is presented. 340 mW of near diffraction limited, single-frequency, and tunable blue light around 459 nm is generated by sum-frequency generation (SFG) between two tunable tapered diode lasers. One diode laser is operated in a ring...... cavity and another tapered diode laser is single-passed through a nonlinear crystal which is contained in the coupled ring cavity. Using this method, the single-pass conversion efficiency is more than 25%. In contrast to SFG in an external cavity, the system is entirely self-stabilized with no electronic...

  6. Accumulation of Phenylpropanoids by White, Blue, and Red Light Irradiation and Their Organ-Specific Distribution in Chinese Cabbage (Brassica rapa ssp. pekinensis).

    Science.gov (United States)

    Kim, Yeon Jeong; Kim, Yeon Bok; Li, Xiaohua; Choi, Su Ryun; Park, Suhyoung; Park, Jong Seok; Lim, Yong Pyo; Park, Sang Un

    2015-08-05

    This study investigated optimum light conditions for enhancing phenylpropanoid biosynthesis and the distribution of phenylpropanoids in organs of Chinese cabbage (Brassica rapa ssp. pekinensis). Blue light caused a high accumulation of most phenolic compounds, including p-hydroxybenzoic acid, ferulic acid, quercetin, and kaempferol, at 12 days after irradiation (DAI). This increase was coincident with a noticeable increase in expression levels of BrF3H, BrF3'H, BrFLS, and BrDFR. Red light led to the highest ferulic acid content at 12 DAI and to elevated expression of the corresponding genes during the early stages of irradiation. White light induced the highest accumulation of kaempferol and increased expression of BrPAL and BrDFR at 9 DAI. The phenylpropanoid content analysis in different organs revealed organ-specific accumulation of p-hydroxybenzoic acid, quercetin, and kaempferol. These results demonstrate that blue light is effective at increasing phenylpropanoid biosynthesis in Chinese cabbage, with leaves and flowers representing the most suitable organs for the production of specific phenylpropanoids.

  7. Two- and 4-hour bright-light exposures differentially effect sleepiness and performance the subsequent night.

    Science.gov (United States)

    Thessing, V C; Anch, A M; Muehlbach, M J; Schweitzer, P K; Walsh, J K

    1994-03-01

    The effect of two durations of bright light upon sleepiness and performance during typical night shift hours was assessed. Thirty normal, healthy young adults participated in a 2-night protocol. On the 1st night subjects were exposed to bright or dim light beginning at 2400 hours, under one of the following three conditions: bright light for 4 hours, dim light for 2 hours followed by bright light for 2 hours or dim light for 4 hours. Following light exposure, subjects remained awake until 0800 hours in a dimly lit room and slept in the laboratory between 0800 and 1600 hours, during which time sleep was estimated with actigraphy. Throughout the 2nd night, the multiple sleep latency test (MSLT), simulated assembly line task (SALT) performance, and subjective sleepiness were recorded. The single, 4-hour exposure to bright light was found to significantly increase MSLT scores and improve SALT performance during the early morning hours on the night following bright-light exposure. No significant effects were noted with a 2-hour exposure. The most likely explanation for these findings is a phase delay in the circadian rhythm of sleepiness-alertness.

  8. Impaired increase of retinal capillary blood flow to flicker light exposure in arterial hypertension.

    Science.gov (United States)

    Ritt, Martin; Harazny, Joanna M; Ott, Christian; Raff, Ulrike; Bauernschubert, Philipp; Lehmann, Marina; Michelson, Georg; Schmieder, Roland E

    2012-09-01

    We hypothesized that the increase of retinal capillary blood flow (RCF) to flicker light exposure is impaired in subjects with arterial hypertension. In 146 nondiabetic untreated male subjects with (n=50) or without (n=96) arterial hypertension, RCF was measured before and after flicker light exposure noninvasively and in vivo using scanning laser Doppler flowmetry. In addition, in a subgroup of 28 subjects, the change of RCF to flicker light exposure was again assessed during parallel infusion of nitric oxide synthase inhibitor N-monomethyl-L-arginine (L-NMMA). The increase of RCF to flicker light exposure was lower in patients with untreated hypertension compared with normotensive subjects when expressed in absolute terms (7.69±54 versus 27.2±44 AU; P adjusted=0.013) or percent changes (2.95±14 versus 8.33±12%; P adjusted=0.023). Systolic (β=-0.216; P=0.023) but not diastolic blood pressure (β=-0.117; P=0.243) or mean arterial pressure (β=-0.178; P=0.073) was negatively related to the percent change of RCF to flicker light exposure, independently of other cardiovascular risk factors. In the subgroup of 28 subjects, the increase of RCF to flicker light exposure was similar at baseline and during parallel infusion of L-NMMA when expressed in absolute terms (20.0±51 versus 22.6±56 AU; P=0.731) or percent changes (7.12±16 versus 8.29±18%; P=0.607). The increase of RCF to flicker light exposure is impaired in arterial hypertension. In the subgroup of the total study cohort, nitric oxide was not a major determinant of the increase of RCF to flicker light exposure.

  9. Bactericidal effect of blue LED light irradiated TiO{sub 2}/Fe{sub 3}O{sub 4} particles on fish pathogen in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, T.C. [Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Taiwan (China); Yao, K.S. [Department of Horticulture, National Taitung Junior College, Taiwan (China); Yeh, N. [Mingdao University, Taiwan (China); Chang, C.I. [Aquaculture Division, Fisheries Research Institute, Council of Agriculture, Taiwan (China); Hsu, H.C. [Department of Life Science, Mingdao University, Taiwan (China); Gonzalez, F. [Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Taiwan (China); Chang, C.Y., E-mail: cyc1136@yahoo.com.tw [Center of General Education, National Taitung Junior College, Taiwan (China)

    2011-05-31

    This study uses blue LED light ({lambda}{sub max} = 475 nm) activated TiO{sub 2}/Fe{sub 3}O{sub 4} particles to evaluate the particles' photocatalytic activity efficiency and bactericidal effects in seawater of variable salinities. Different TiO{sub 2} to Fe{sub 3}O{sub 4} mole ratios have been synthesized using sol-gel method. The synthesized particles contain mainly anatase TiO{sub 2}, Fe{sub 3}O{sub 4} and FeTiO{sub 3}. The study has identified TiO{sub 2}/Fe{sub 3}O{sub 4}'s bactericidal effect to marine fish pathogen (Photobacterium damselae subsp. piscicida BCRC17065) in seawater. The SEM photo reveals the surface destruction in bacteria incubated with blue LED irradiated TiO{sub 2}/Fe{sub 3}O{sub 4}. The result of this study indicates that 1) TiO{sub 2}/Fe{sub 3}O{sub 4} acquires photocatalytic activities in both the freshwater and the seawater via blue LED irradiation, 2) higher photocatalytic activities appear in solutions of higher TiO{sub 2}/Fe{sub 3}O{sub 4} mole ratio, and 3) photocatalytic activity decreases as salinity increases. These results suggest that the energy saving blue LED light is a feasible light source to activate TiO{sub 2}/Fe{sub 3}O{sub 4} photocatalytic activities in both freshwater and seawater.

  10. Electroplex as a New Concept of Universal Host for Improved Efficiency and Lifetime in Red, Yellow, Green, and Blue Phosphorescent Organic Light-Emitting Diodes.

    Science.gov (United States)

    Song, Wook; Lee, Jun Yeob; Cho, Yong Joo; Yu, Hyeonghwa; Aziz, Hany; Lee, Kang Mun

    2018-02-01

    A new concept of host, electroplex host, is developed for high efficiency and long lifetime phosphorescent organic light-emitting diodes by mixing two host materials generating an electroplex under an electric field. A carbazole-type host and a triazine-type host are selected as the host materials to form the electroplex host. The electroplex host is found to induce light emission through an energy transfer process rather than charge trapping, and universally improves the lifetime of red, yellow, green, and blue phosphorescent organic light-emitting diodes by more than four times. Furthermore, the electroplex host shows much longer lifetime than a common exciplex host. This is the first demonstration of using the electroplex as the host of high efficiency and long lifetime phosphorescent organic light-emitting diodes.

  11. Highly efficient blue organic light emitting device using indium-free transparent anode Ga:ZnO with scalability for large area coating

    International Nuclear Information System (INIS)

    Wang Liang; Matson, Dean W.; Polikarpov, Evgueni; Swensen, James S.; Bonham, Charles C.; Cosimbescu, Lelia; Gaspar, Daniel J.; Padmaperuma, Asanga B.; Berry, Joseph J.; Ginley, David S.

    2010-01-01

    Organic light emitting devices have been achieved with an indium-free transparent anode, Ga doped ZnO (GZO). A large area coating technique was used (RF magnetron sputtering) to deposit the GZO films onto glass. The respective organic light emitting devices exhibited an operational voltage of 3.7 V, an external quantum efficiency of 17%, and a power efficiency of 39 lm/W at a current density of 1 mA/cm 2 . These parameters are well within acceptable standards for blue OLEDs to generate a white light with high enough brightness for general lighting applications. It is expected that high-efficiency, long-lifetime, large area, and cost-effective white OLEDs can be made with these indium-free anode materials.

  12. Blue gods, blue oil, and blue people.

    Science.gov (United States)

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today.

  13. Bilirubin isomer distribution in jaundiced neonates during phototherapy with LED light centered at 497 nm (turquoise) vs. 459 nm (blue).

    Science.gov (United States)

    Ebbesen, Finn; Madsen, Poul H; Vandborg, Pernille K; Jakobsen, Lasse H; Trydal, Torleif; Vreman, Hendrik J

    2016-10-01

    Phototherapy using blue light is the treatment of choice worldwide for neonatal hyperbilirubinemia. However, treatment with turquoise light may be a desirable alternative. Therefore, the aim of this randomized, controlled study was to compare the bilirubin isomer distribution in serum of jaundiced neonates after 24 h of therapy with narrow-band (LED) light centered at 497 nm (turquoise) vs. 459 nm (blue), of essentially equal irradiance. Eighty-three neonates (≥33 wk gestational age) with uncomplicated hyperbilirubinemia were included in the study. Forty neonates were exposed to light centered at 497 nm and 43 infants with light centered at 459 nm. Irradiances were 5.2 × 10(15) and 5.1 × 10(15) photons/cm(2)/s, respectively. After 24 h of treatment no significant differences in serum concentrations of total bilirubin isomers and Z,Z-bilirubin were observed between the 2 groups. Interestingly, concentrations of Z,E-bilirubin, and thus also total bilirubin isomers formed during therapy, were highest for infants receiving light centered at 459 nm, while the concentration of E,Z-bilirubin was highest for those receiving light centered at 497 nm. No significant difference was found between concentrations of E,Z-lumirubin. Therapy with LED light centered at 497 nm vs. 459 nm, applied with equal irradiance on the infants, resulted in a different distribution of bilirubin isomers in serum.

  14. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  15. Treatment Results of Corneal Collagen Cross-Linking Combined with Riboflavin and 440 Nm Blue Light for Bacterial Corneal Ulcer in Rabbits.

    Science.gov (United States)

    Wei, Shufang; Zhang, Cuiying; Zhang, Shaoru; Xu, Yanyun; Mu, Guoying

    2017-10-01

    To study the treatment effect of corneal collagen cross-linking (CXL) combined with 440 nm blue light and riboflavin on bacterial corneal ulcer using animal experiments. A total of 21 New Zealand white rabbits that developed Staphylococcus aureus corneal ulcer were randomly divided into three groups. Seven rabbits were used as blank control groups; seven rabbits were treated with CXL combined with riboflavin and 440 nm blue light; and seven rabbits were treated with CXL combined with riboflavin and 370 nm ultraviolet A light. Necrotic tissues or secretions from the ulcer surface, eye secretions, conjunctival hyperemia, hypopyon, corneal infiltration, and pathological changes of the cornea were all observed. The 1st, 3th, and 7th day after CXL treatment, a statistically significant difference was found among the inflammation scores of the three groups. The scores of 440 and 370 groups decreased gradually, significantly lower than that of the control group. Bacterial cultures of 440 and 370 groups turned to be negative while that of the control group remained positive. After 1 day of CXL treatment, pathology pictures of the three groups all showed loss of corneal epithelia with many inflammatory cells in deep stroma. After 7 days of CXL treatment, abscess formed in almost all corneal area in the control group, while in 440 and 370 groups, multilayer healing of corneal epithelia, neovascularization, and many inflammatory cells within ulcers and proliferation of a small amount of fibroblast were seen. CXL combined with riboflavin and 440 nm blue light is effective in treating S. aureus corneal ulcer.

  16. Reverse leakage current characteristics of InGaN/GaN multiple quantum well ultraviolet/blue/green light-emitting diodes

    Science.gov (United States)

    Zhou, Shengjun; Lv, Jiajiang; Wu, Yini; Zhang, Yuan; Zheng, Chenju; Liu, Sheng

    2018-05-01

    We investigated the reverse leakage current characteristics of InGaN/GaN multiple quantum well (MQW) near-ultraviolet (NUV)/blue/green light-emitting diodes (LEDs). Experimental results showed that the NUV LED has the smallest reverse leakage current whereas the green LED has the largest. The reason is that the number of defects increases with increasing nominal indium content in InGaN/GaN MQWs. The mechanism of the reverse leakage current was analyzed by temperature-dependent current–voltage measurement and capacitance–voltage measurement. The reverse leakage currents of NUV/blue/green LEDs show similar conduction mechanisms: at low temperatures, the reverse leakage current of these LEDs is attributed to variable-range hopping (VRH) conduction; at high temperatures, the reverse leakage current of these LEDs is attributed to nearest-neighbor hopping (NNH) conduction, which is enhanced by the Poole–Frenkel effect.

  17. Exposure to red light, temperature and exogenous gibberellins ...

    African Journals Online (AJOL)

    Red light, temperature and gibberellins are well known for their capacity to induce higher germination in dormant seeds of several plant species. In the current study, we investigated the effect of various temperature (10, 13, 16, 19, 22 and 25°C) and gibberellic acid (GA3) and GA4+7 concentrations (0.1, 1, 10, and 100 uM) ...

  18. Exposure to 4100K fluorescent light elicits sex specific transcriptional responses in Xiphophorus maculatus skin.

    Science.gov (United States)

    Boswell, William T; Boswell, Mikki; Walter, Dylan J; Navarro, Kaela L; Chang, Jordan; Lu, Yuan; Savage, Markita G; Shen, Jianjun; Walter, Ronald B

    2018-06-01

    It has been reported that exposure to artificial light may affect oxygen intake, heart rate, absorption of vitamins and minerals, and behavioral responses in humans. We have reported specific gene expression responses in the skin of Xiphophorus fish after exposure to ultraviolet light (UV), as well as, both broad spectrum and narrow waveband visible light. In regard to fluorescent light (FL), we have shown that male X. maculatus exposed to 4100K FL (i.e. "cool white") rapidly suppress transcription of many genes involved with DNA replication and repair, chromosomal segregation, and cell cycle progression in skin. We have also detailed sex specific transcriptional responses of Xiphophorus skin after exposure to UVB. However, investigation of gender differences in global gene expression response after exposure to 4100K FL has not been reported, despite common use of this FL source for residential, commercial, and animal facility illumination. Here, we compare RNA-Seq results analyzed to assess changes in the global transcription profiles of female and male X. maculatus skin in response to 4100K FL exposure. Our results suggest 4100K FL exposure incites a sex-biased genetic response including up-modulation of inflammation in females and down modulation of DNA repair/replication in males. In addition, we identify clusters of genes that become oppositely modulated in males and females after FL exposure that are principally involved in cell death and cell proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Association of Light Exposure on Physical Activity and Sedentary Time in Young People

    Directory of Open Access Journals (Sweden)

    Daniel Aggio

    2015-03-01

    Full Text Available Background: To investigate whether light exposure was associated with objectively measured physical activity (PA and sedentary behaviour in young people. Methods: Participants (n = 229, 46.7% female were young people (mean 8.8 years [SD ± 2.2] from the borough of Camden, UK. Daily sedentary time, moderate and vigorous PA (MVPA and light exposure were measured using a tri-axial accelerometer with an ambient light sensor during the summer. Multiple linear regression models examined associations between average daily light exposure, sedentary time and time in MVPA. Models were repeated investigating weekdays and weekend days separately. Analyses were adjusted for pre-specified covariables, including age, sex, device wear time, ethnic group, school and body fat. Results: There were significant associations between average daily light exposure and time sedentary (β coefficient = −11.2, 95% CI, −19.0 to −3.4 and in MVPA (β coefficient = 3.5, 95% CI, 1.2 to 5.9. Light exposure was significantly associated with weekend sedentary time (β coefficient = −10.0, 95% CI, −17.6, −2.4, weekend MVPA (β coefficient = 3.7, 95% CI, 1.7, 5.7, weekday sedentary time (β coefficient = −15.0, 95% CI, −22.7 to −7.2, but not weekday MVPA (β coefficient = 2.0, 95% CI, −0.5 to 4.5. Conclusion: Average daily light exposure is positively associated with time in MVPA and negatively associated with sedentary time. Increasing daylight exposure may be a useful intervention strategy for promoting physical activity.

  20. Aging characteristics of blue InGaN micro-light emitting diodes at an extremely high current density of 3.5 kA cm−2

    International Nuclear Information System (INIS)

    Tian, Pengfei; Liu, Ran; Althumali, Ahmad; Gu, Erdan; Watson, Ian M; Dawson, Martin D

    2016-01-01

    The aging characteristics of blue InGaN micro-light emitting diodes (micro-LEDs) with different sizes have been studied at an extremely high current density 3.5 kA cm −2 for emerging micro-LED applications including visible light communication (VLC), micro-LED pumped organic lasers and optogenetics. The light output power of micro-LEDs first increases and then decreases due to the competition of Mg activation in p-GaN layer and defect generation in the active region. The smaller micro-LEDs show less light output power degradation compared with larger micro-LEDs, which is attributed to the lower junction temperature of smaller micro-LEDs. It is found that the high current density without additional junction temperature cannot induce significant micro-LED degradation at room temperature but the combination of the high current density and high junction temperature leads to strong degradation. Furthermore, the cluster LEDs, composed of a micro-LED array, have been developed with both high light output power and less light output degradation for micro-LED applications in solid state lighting and VLC. (paper)

  1. Astrophotography on the go using short exposures with light mounts

    CERN Document Server

    Ashley, Joseph

    2015-01-01

    No longer are heavy, sturdy, expensive mounts and tripods required to photograph deep space. With today's advances in technology, all that is required is an entry-DSLR and an entry level GoTo telescope. Here is all of the information needed to start photographing the night sky without buying expensive tracking mounts. By using multiple short exposures and combining them with mostly ‘freeware’ computer programs, the effect of image rotation can be minimized to a point where it is undetectable in normal astrophotography, even for a deep-sky object such as a galaxy or nebula. All the processes, techniques, and equipment needed to use inexpensive, lightweight altazimuth and equatorial mounts and very short exposures photography to image deep space objects are explained, step-by-step, in full detail, supported by clear, easy to understand graphics and photographs.   Currently available lightweight mounts and tripods are identified and examined from an economic versus capability perspective to help users deter...

  2. White organic light-emitting diodes utilized by near UV-deep blue emitter and exciplex emission.

    Science.gov (United States)

    Park, Young Wook; Kim, Young Min; Choi, Jin Hwan; Park, Tae Hyun; Choi, Hyun Ju; Yu, Hong Jung; Cho, Min Ju; Choi, Dong Hoon; Kim, Sung Hyun; Ju, Byeong Kwon

    2011-02-01

    Numerous investigations have been made into the development of wide color gamut displays for deep-blue OLEDs, including the RGB sub pixels, and white OLEDs (WOLEDs). One of the well known deep-blue emissive dopants, tris(phenyl-methyl-benzimidazolyl)iridium(III) [Ir(pmb)3], successfully introduced its fascinating color coordinate of Commission Internationale de l'Eclairage (CIE) 1931 (0.17, 0.06), however there have been no reports utilizing its accomplishments as WOLEDs. In this report, using only one phosphorescent dopant, the near UV-deep blue emissive Ir(pmb)3, the WOLEDs having the CIE 1931 coordinate of (0.33, 0.38) at 100 cd/m2 with a color rendering index of 85 are demonstrated. The white emission of the fabricated OLEDs are oriented from the near UV-deep blue emission of Ir(pmb)3 and the successfully controlled exciplex emission, between the Ir(pmb)3-host, and the Ir(pmb)3-interfaced material.

  3. Global Trends in Exposure to Light Pollution in Natural Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Jonathan Bennie

    2015-03-01

    Full Text Available The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000 to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.

  4. The behavior of thermally and optically stimulated luminescence of SrAl2O4:Eu2+,Dy3+ long persistent phosphor after blue light illumination

    International Nuclear Information System (INIS)

    Chernov, V.; Melendrez, R.; Pedroza-Montero, M.; Yen, W.M.; Barboza-Flores, M.

    2008-01-01

    The behavior of afterglow (AG), thermoluminescence (TL), infrared stimulated luminescence (IRSL) and phototransferred TL (PTTL) under thermal and/or infrared (IR) stimulation in blue (470 nm) light illuminated at room temperature (RT) SrAl 2 O 4 :Eu 2+ , Dy 3+ is presented. The TL glow curve consists of four peaks with maxima at about 340, 430, 560 and 680 K. The 340 and 440 K peaks are described well by second order kinetics with activation energies of 0.83 and 1.05 eV, respectively. The AG decay is fitted by the Becquerel's law with exponent 1.5 and correlates well with the thermal emptying of the traps responsible for the 340 K peak. The 340 and 430 K TL peak traps are destroyed under IR (830 nm) stimulation creating IRSL. IR stimulation after illumination with blue light and preliminary heating restore partially the 340 and 430 K TL peaks by phototransfer from deeper traps. The shape of the IRSL decay curves depends strongly on the preheating temperature and is determined by simultaneous refilling of the 340 and 430 K TL traps and their reverse filling due to phototransfer from the deeper traps under IR stimulation. The obtained data are interpreted by the transformation of Eu 2+ and Dy 3+ to Eu 3+ and Dy 2+ under blue light illumination and their reverse transformation under thermal or IR stimulation. The Eu 2+ ions are the luminescent centers and the Dy 2+ centers are the IR sensitive traps responsible for the TL peaks, AG and IRSL

  5. Exploring the Impact of Natural Light Exposure on Sleep of Healthy Older Adults: A Field Study

    Directory of Open Access Journals (Sweden)

    Mariëlle P. J. Aarts

    2018-05-01

    Full Text Available Studies among people with dementia demonstrated that the sleep quality and rhythm improves significantly when people are exposed to ambient bright light. Since almost half of the healthy older people also indicate to suffer from chronic sleep disorders, the question arises whether ambient bright light can be beneficial to healthy older people. Particularly the effect on sleep/wake rhythm in relation to the exposure to natural light is the focus. It was hypothesised that the sleep quality would be worse in winter due to a lower daylight dose than in summer due to the lower illuminance and exposure duration. A field study was conducted to examine the relationship between daylight exposure and sleep quality in 14 healthy older adults living independently in their own dwellings in the Netherlands. All participants were asked to take part of the study both during the summer period as well as during the winter period. Therefore, they had to wear an actigraph for five consecutive days which measured sleep, activity and light exposure. Results confirmed that people were significantly longer exposed to high illumination levels (>1000 lx in summer than in winter. Sleep quality measures, however, did not differ significantly between summer and winter. A significant, positive correlation was found between exposure duration to high illuminance from daylight during the day and the sleep efficiency the following night in summer, implying that being exposed to high illuminance for a longer time period has a positive effect on sleep efficiency for the individual data. There was also a tendency of less frequent napping in case of longer exposure duration to light for both seasons. Sleep quality does not differ between summer and winter but is related to the duration of the exposure to bright light the day prior to the night.

  6. Multiple experimental approaches of immunotoxic effects of mercury chloride in the blue mussel, Mytilus edulis, through in vivo, in tubo and in vitro exposures

    International Nuclear Information System (INIS)

    Duchemin, Matthieu B.; Auffret, Michel; Wessel, Nathalie; Fortier, Marlene; Morin, Yves; Pellerin, Jocelyne; Fournier, Michel

    2008-01-01

    Biological impairments due to mercury discharge into the environment are now an issue of global concern. From the three forms of mercury found in aquatic ecosystems, the immunotoxic effects of mercury chloride were examined in the model animal, the blue mussel. In order to investigate the toxic potency of this chemical, three exposure regimes were carried out: chronic exposure of groups of individuals, a new protocol 'in tubo' designed for sub-acute exposures of individuals, and acute exposures of target cells. Chronic exposure revealed significant immunotoxic effects after 7 days at 10 -6 M, while acute exposures showed significant inhibition of phagocytosis at 10 -4 M and 10 -3 M. In sub-acute exposures both circulating haemocytes and haemocyte mortality increased at 10 -4 M and 10 -3 M while phagocytosis and the clearance rate drew hormetic toxic effects on healthy individuals. These results suggest the use of the 'in tubo' design for bivalve toxicological individual studies. - HgCl 2 impairs the immune system of test-tube mussels

  7. Long-term reduction in infrared autofluorescence caused by infrared light below the maximum permissible exposure.

    Science.gov (United States)

    Masella, Benjamin D; Williams, David R; Fischer, William S; Rossi, Ethan A; Hunter, Jennifer J

    2014-05-20

    Many retinal imaging instruments use infrared wavelengths to reduce the risk of light damage. However, we have discovered that exposure to infrared illumination causes a long-lasting reduction in infrared autofluorescence (IRAF). We have characterized the dependence of this effect on radiant exposure and investigated its origin. A scanning laser ophthalmoscope was used to obtain IRAF images from two macaques before and after exposure to 790-nm light (15-450 J/cm(2)). Exposures were performed with either raster-scanning or uniform illumination. Infrared autofluorescence images also were obtained in two humans exposed to 790-nm light in a separate study. Humans were assessed with direct ophthalmoscopy, Goldmann visual fields, multifocal ERG, and photopic microperimetry to determine whether these measures revealed any effects in the exposed locations. A significant decrease in IRAF after exposure to infrared light was seen in both monkeys and humans. In monkeys, the magnitude of this reduction increased with retinal radiant exposure. Partial recovery was seen at 1 month, with full recovery within 21 months. Consistent with a photochemical origin, IRAF decreases caused by either raster-scanning or uniform illumination were not significantly different. We were unable to detect any effect of the light exposure with any measure other than IRAF imaging. We cannot exclude the possibility that changes could be detected with more sensitive tests or longer follow-up. This long-lasting effect of infrared illumination in both humans and monkeys occurs at exposure levels four to five times below current safety limits. The photochemical basis for this phenomenon remains unknown. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  8. Effect of ambient light exposure of media and embryos on development and quality of porcine parthenogenetically activated embryos

    DEFF Research Database (Denmark)

    Li, Rong; Liu, Ying; Callesen, Henrik

    2015-01-01

    Light exposure is a common stress factor during in vitro handling of oocytes and embryos that originates from both microscope and ambient light. In the current study, the effect of two types of ambient light (daylight and laboratory light) on porcine parthenogenetically activated (PA) embryos...... was tested in two experiments: (1) ambient light on medium subsequently used for embryo in vitro development; and (2) ambient light exposure on activated oocytes before in vitro development. The results from Experiment 1 showed that exposure of culture medium to both types of ambient light decreased...... the percentage of blastocysts that showed good morphology, only after 24 h exposure. The results from Experiment 2 revealed a reduction in both blastocyst formation and quality when activated oocytes were exposed to both types of ambient light. This effect was seen after only 1 h exposure and increased with time...

  9. Organic light-emitting diodes based on 9-(2-naphthyl)anthracene derivatives with a triphenylsilane unit as the deep-blue emitting layer

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ji Young; Lee, Seul Bee [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Seok Jae [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@wow.hongik.ac.kr [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-02-27

    A series of 9-(2-naphthyl)anthracene derivatives with a triphenylsilane unit, which prevented molecular aggregation and self-quenching effect, was designed and synthesized. By using various bridges between the 9-(2-naphthyl)anthracene group and the triphenylsilane unit, five deep-blue emitters were obtained and applied as non-doped emitting materials in organic light-emitting diodes (OLEDs) with a device structure of indium–tin-oxide (ITO) (180 nm)/4,4-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) (50 nm)/emitting materials (30 nm)/4,7-diphenyl-1,10-phenanthroline (Bphen) (30 nm)/lithium quinolate (Liq) (2 nm)/Aluminium (100 nm). All devices showed blue emissions and their electroluminescence efficiencies are sensitive to the structural changes of the emitting materials. In particular, a device using 9-(2-naphthalenyl)-10-[6-(triphenylsilyl)-2-naphthalenyl]-anthracene (4) exhibited high luminous, power and quantum efficiencies of 2.28 cd/A, 1.42 lm/W and 2.40% at 20 mA/cm{sup 2}, respectively, and this device showed the deep blue emission with the CIE coordinates of (0.16, 0.10) at 6.0 V. - Highlights: • We synthesized 9-(2-naphthyl)anthracene derivatives with a triphenylsilane unit. • We study the conjugation-length effect on the electroluminescence properties. • The bulky triphenylsilane-anthracene derivatives show resistance to self-aggregation.

  10. Visible Light-Induced Degradation of Methylene Blue in the Presence of Photocatalytic ZnS and CdS Nanoparticles

    Directory of Open Access Journals (Sweden)

    Parisa Vaziri

    2012-09-01

    Full Text Available ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10−3 min−1. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution.

  11. Doping-free white organic light-emitting diodes without blue molecular emitter: An unexplored approach to achieve high performance via exciplex emission

    Science.gov (United States)

    Luo, Dongxiang; Xiao, Ye; Hao, Mingming; Zhao, Yu; Yang, Yibin; Gao, Yuan; Liu, Baiquan

    2017-02-01

    Doping-free white organic light-emitting diodes (DF-WOLEDs) are promising for the low-cost commercialization because of their simplified device structures. However, DF-WOLEDs reported thus far in the literature are based on the use of blue single molecular emitters, whose processing can represent a crucial point in device manufacture. Herein, DF-WOLEDs without the blue single molecular emitter have been demonstrated by managing a blue exciplex system. For the single-molecular-emitter (orange or yellow emitter) DF-WOLEDs, (i) a color rendering index (CRI) of 81 at 1000 cd/m2 can be obtained, which is one of the highest for the single-molecular-emitter WOLEDs, or (ii) a high efficiency of 35.4 lm/W can be yielded. For the dual-molecular-emitter (yellow/red emitters) DF-WOLED, a high CRI of 85 and low correlated color temperature of 2376 K at 1000 cd/m2 have been simultaneously achieved, which has not been reported by previous DF-WOLEDs. Such presented findings may unlock an alternative avenue to the simplified but high-performance WOLEDs.

  12. Effect of evening exposure to bright or dim light after daytime bright light on absorption of dietary carbohydrates the following morning.

    Science.gov (United States)

    Hirota, Naoko; Sone, Yoshiaki; Tokura, Hiromi

    2010-01-01

    We had previously reported on the effect of exposure to light on the human digestive system: daytime bright light exposure has a positive effect, whereas, evening bright light exposure has a negative effect on the efficiency of dietary carbohydrate absorption from the evening meal. These results prompted us to examine whether the light intensity to which subjects are exposed in the evening affects the efficiency of dietary carbohydrate absorption the following morning. In this study, subjects were exposed to either 50 lux (dim light conditions) or 2,000 lux (bright light conditions) in the evening for 9 h (from 15:00 to 24:00) after staying under bright light in the daytime (under 2,000 lux from 07:00 to 15:00). We measured unabsorbed dietary carbohydrates using the breath-hydrogen test the morning after exposure to either bright light or dim light the previous evening. Results showed that there was no significant difference between the two conditions in the amount of breath hydrogen. This indicates that evening exposure to bright or dim light after bright light exposure in the daytime has no varying effect on digestion or absorption of dietary carbohydrates in the following morning's breakfast.

  13. Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes

    Directory of Open Access Journals (Sweden)

    Fábio Rogério Cury

    2008-06-01

    Full Text Available In this work we investigated the effect of visible radiation on the electrical properties of poly[(2-methoxy-5-hexyloxy-p-phenylenevinylene]- MH-PPV films and light emitting diodes. Complex impedance measurements of (Au or ITO/MH-PPV/(Au or Al samples were carried out at room temperature and exposed to white light. Over the frequency range from 100 mHz to 2 MHz, the electrical results of Au/MH-PPV/Au was dominated by the Cole-Cole approach, where the electrode influence is negligible. However, some additional influence of the interface was observed to occur when Al was used as electrode. These effects were observed under both dark and visible-light illumination conditions. A simple model based on resistor-capacitor parallel circuits was developed to represent the complex impedance of the samples, thereby separating bulk and interface contributions. We observed that the polymer electrical resistivity decreased while the dielectric constant of the polymer and the thickness of the Al/MH-PPV layer were almost constant with increasing light intensity. The decrease of the polymer layer resistance comes from a better charge injection due to a light induced dissociation of positive charge carriers at the electrode.

  14. Light emission ranging from blue to red from a series of Iguana/GaN single quantum wells

    International Nuclear Information System (INIS)

    Martin, R.W.; Edwards, P.R.; Pecharroman-Gallego, R.; O'Donnell, K.P.; Liu, C.; Deatcher, C.J.; Watson, I.M.

    2002-01-01

    In this paper, we describe the growth and characterization of InGaN single quantum wells with emission peaks in the blue, green, amber and red spectral regions, grown by metal-organic vapour phase epitaxy. Starting from the growth of a blue-emitting (peak ∼430 nm) InGaN quantum well at 860 deg. C the InGaN growth temperature was progressively reduced. The photoluminescence peak wavelength, measured at low temperature, shifts through the green and orange spectral regions and reaches 670 nm for an InGaN growth temperature of 760 deg. C. This corresponds to an energy lower than the currently accepted band-gap of the binary compound, InN. Spectral characteristics of the luminescence peaks will be discussed, including an analysis of the phonon-assisted contribution. Low energy secondary ion mass spectrometry analysis provides information on the indium content and thickness of the 'blue' and 'red' quantum wells. The results are combined to discuss the origin of the 'sub-band-gap' luminescence in terms of the combined influence of InN-GaN segregation and the effect of intense piezoelectric fields. (author)

  15. Light emission ranging from blue to red from a series of Iguana/GaN single quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.W. [Department of Physics, University of Strathclyde, Glasgow (United Kingdom)]. E-mail: r.w.martin@strath.ac.uk; Edwards, P.R.; Pecharroman-Gallego, R.; O' Donnell, K.P. [Department of Physics, University of Strathclyde, Glasgow (United Kingdom); Liu, C.; Deatcher, C.J.; Watson, I.M. [Institute of Photonics, University of Strathclyde, Glasgow (United Kingdom)

    2002-04-07

    In this paper, we describe the growth and characterization of InGaN single quantum wells with emission peaks in the blue, green, amber and red spectral regions, grown by metal-organic vapour phase epitaxy. Starting from the growth of a blue-emitting (peak {approx}430 nm) InGaN quantum well at 860 deg. C the InGaN growth temperature was progressively reduced. The photoluminescence peak wavelength, measured at low temperature, shifts through the green and orange spectral regions and reaches 670 nm for an InGaN growth temperature of 760 deg. C. This corresponds to an energy lower than the currently accepted band-gap of the binary compound, InN. Spectral characteristics of the luminescence peaks will be discussed, including an analysis of the phonon-assisted contribution. Low energy secondary ion mass spectrometry analysis provides information on the indium content and thickness of the 'blue' and 'red' quantum wells. The results are combined to discuss the origin of the 'sub-band-gap' luminescence in terms of the combined influence of InN-GaN segregation and the effect of intense piezoelectric fields. (author)

  16. Untargeted Metabolomics Reveals Predominant Alterations in Lipid Metabolism Following Light Exposure in Broccoli Sprouts

    Directory of Open Access Journals (Sweden)

    Mariateresa Maldini

    2015-06-01

    Full Text Available The consumption of vegetables belonging to the family Brassicaceae (e.g., broccoli and cauliflower is linked to a reduced incidence of cancer and cardiovascular diseases. The molecular composition of such plants is strongly affected by growing conditions. Here we developed an unbiased metabolomics approach to investigate the effect of light and dark exposure on the metabolome of broccoli sprouts and we applied such an approach to provide a bird’s-eye view of the overall metabolic response after light exposure. Broccoli seeds were germinated and grown hydroponically for five days in total darkness or with a light/dark photoperiod (16 h light/8 h dark cycle. We used an ultra-performance liquid-chromatography system coupled to an ion-mobility, time-of-flight mass spectrometer to profile the large array of metabolites present in the sprouts. Differences at the metabolite level between groups were analyzed using multivariate statistical analyses, including principal component analysis and correlation analysis. Altered metabolites were identified by searching publicly available and in-house databases. Metabolite pathway analyses were used to support the identification of subtle but significant changes among groups of related metabolites that may have gone unnoticed with conventional approaches. Besides the chlorophyll pathway, light exposure activated the biosynthesis and metabolism of sterol lipids, prenol lipids, and polyunsaturated lipids, which are essential for the photosynthetic machinery. Our results also revealed that light exposure increased the levels of polyketides, including flavonoids, and oxylipins, which play essential roles in the plant’s developmental processes and defense mechanism against herbivores. This study highlights the significant contribution of light exposure to the ultimate metabolic phenotype, which might affect the cellular physiology and nutritional value of broccoli sprouts. Furthermore, this study highlights the

  17. The Use of Ultra-Violet (UV) Light Emitting Diodes (LEDS) in an Advanced Oxidation Process (AOP) with Brilliant Blue FCF as an Indicator

    Science.gov (United States)

    2015-03-26

    LEDs have the potential to replace mercury lamps in many UV processes, as well as open the door to new applications of UV light based on their unique...al. 2007, Autin, Romelot, et al. 2013). UV LEDs in AOPs While most data on AOP experimentation are based on experiments that use mercury lamps ...metaldehyde in solution. Their experiments found that similar UV light exposure levels from UV LEDs and traditional mercury lamps produced similar

  18. Effects of blue light irradiation on dental enamel remineralization in vitro; Avaliacao dos efeitos promovidos pela radiacao azul na remineralizacao do esmalte dentario in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ilka Tiemy

    2009-07-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm{sup 2} e 6.25 mL/mm{sup 2}). The lesions were irradiated with blue LED (l=455{+-}20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm{sup 2}, radiant exposure of 13.8 J/{sup c}m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  19. Exposure of fluid milk to LED light negatively affects consumer perception and alters underlying sensory properties.

    Science.gov (United States)

    Martin, Nicole; Carey, Nancy; Murphy, Steven; Kent, David; Bang, Jae; Stubbs, Tim; Wiedmann, Martin; Dando, Robin

    2016-06-01

    Fluid milk consumption per capita in the United States has been steadily declining since the 1940s. Many factors have contributed to this decline, including the increasing consumption of carbonated beverages and bottled water. To meet the challenge of stemming the decline in consumption of fluid milk, the dairy industry must take a systematic approach to identifying and correcting for factors that negatively affect consumers' perception of fluid milk quality. To that end, samples of fluid milk were evaluated to identify factors, with a particular focus on light-emitting diode (LED) light exposure, which negatively affect the perceived sensory quality of milk, and to quantify their relative effect on the consumer's experience. Fluid milk samples were sourced from 3 processing facilities with varying microbial postprocessing contamination patterns based on historical testing. The effect of fat content, light exposure, age, and microbiological content were assayed across 23 samples of fluid milk, via consumer, descriptive sensory, and instrumental analyses. Most notably, light exposure resulted in a broad negative reaction from consumers, more so than samples with microbiological contamination exceeding 20,000 cfu/mL on days approaching code. The predominant implication of the study is that a component of paramount importance in ensuring the success of the dairy industry would be to protect fluid milk from all sources of light exposure, from processing plant to consumer. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Parental Exposure to Dim Light at Night Prior to Mating Alters Offspring Adaptive Immunity

    OpenAIRE

    Ciss?, Yasmine M.; Russart, Kathryn L.G.; Nelson, Randy J.

    2017-01-01

    Exposure to dim light at night (dLAN) disrupts natural light/dark cycles and impairs endogenous circadian rhythms necessary to maintain optimal biological function, including the endocrine and immune systems. We have previously demonstrated that white dLAN compromises innate and cell mediated immune responses in adult Siberian hamsters (Phodopus sungorus). We hypothesized that dLAN has transgenerational influences on immune function. Adult male and female Siberian hamsters were exposed to eit...

  1. Exposure to dim light at night during early development increases adult anxiety-like responses.

    Science.gov (United States)

    Borniger, Jeremy C; McHenry, Zachary D; Abi Salloum, Bachir A; Nelson, Randy J

    2014-06-22

    Early experiences produce effects that may persist throughout life. Therefore, to understand adult phenotype, it is important to investigate the role of early environmental stimuli in adult behavior and health. Artificial light at night (LAN) is an increasingly common phenomenon throughout the world. However, animals, including humans, evolved under dark night conditions. Many studies have revealed affective, immune, and metabolic alterations provoked by aberrant light exposure and subsequent circadian disruption. Pups are receptive to entraining cues from the mother and then light early during development, raising the possibility that the early life light environment may influence subsequent behavior. Thus, to investigate potential influences of early life exposure to LAN on adult phenotype, we exposed mice to dim (~5 lux; full spectrum white light) or dark (~0 lux) nights pre- and/or postnatally. After weaning at 3 weeks of age, all mice were maintained in dark nights until adulthood (9 weeks of age) when behavior was assessed. Mice exposed to dim light in early life increased anxiety-like behavior and fearful responses on the elevated plus maze and passive avoidance tests. These mice also displayed reduced growth rates, which ultimately normalized during adolescence. mRNA expression of brain derived neurotrophic factor (BDNF), a neurotrophin previously linked to early life environment and adult phenotype, was not altered in the prefrontal cortex or hippocampus by early life LAN exposure. Serum corticosterone concentrations were similar between groups at weaning, suggesting that early life LAN does not elicit a long-term physiologic stress response. Dim light exposure did not influence behavior on the open field, novel object, sucrose anhedonia, or forced swim tests. Our data highlight the potential deleterious consequences of low levels of light during early life to development and subsequent behavior. Whether these changes are due to altered maternal behavior

  2. Biosynthetic pathways to delta-aminolevulinic acid induced by blue light in the pigment mutant C-2A' of Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Klein, O.; Senger, H.

    1978-01-01

    The X-ray induced mutant C-2A' of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, delta-aminolevulinic acid (ALA) is synthesized and chlorophyll is formed. These processes are blue light dependent and ceased immediately when the cells were transferred back into darkness. Addition of levulinic acid (LA) inhibited the light-dependent formation of chlorophyll and caused accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled 14 C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominated over the glutamate pathway, but both led to chlorophyll formation. (author)

  3. Exposure to scenic lighting devices: risk to the health of entertainment professionals

    International Nuclear Information System (INIS)

    Salsi, S.; Barlier-Salsi, A.

    2013-01-01

    The European directive 2006/25/EC on minimum health and safety requirements regarding the exposure of workers to the risks arising from optical radiation provides for risk assessment in workplaces. This is particularly important in entertainment, where intentional exposure to spotlights may be required for periods of 8 hours per working day. The aim of the study was to provide the lighting engineers with information, relative to the risks associated with spotlights, to help them to estimate the risks a priori of a lighting plan. This study consisted of determining the risks associated with 63 different spotlights, then distributing them into 4 groups of risks defined by the standard EN 62471, in calculating their permissible minimal exposure distance, corresponding to the use of 1 and 5 spotlights for a daily exposure time of 8 hours. This study highlighted that spotlights may cause health problems for entertainment workers. The classification proposed by the standard EN 62471 is not sufficient to estimate the risks of a lighting plan. Furthermore, the permissible minimal exposure distance and the permissible maximal exposure time do not constitute relevant parameters to reduce the risks to acceptable values. (authors)

  4. MoS{sub 2}–GO nanocomposites synthesized via a hydrothermal hydrogel method for solar light photocatalytic degradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yong; Zhou, Yifeng, E-mail: yifengzhou@126.com; Nie, Wangyan; Chen, Pengpeng, E-mail: chenpp@ahu.edu.cn

    2015-12-01

    Graphical abstract: - Highlights: • The molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) nanocomposite was synthesized via a one-step hydrothermal hydrogel method. • MoS{sub 2} and GO were composited fairly well in the obtained nanocomposites. • The electrons–hole pair recombination rate of MoS{sub 2} was greatly reduced via compositing with graphene. • The MoS{sub 2}–GO nanocomposite exhibited excellent photocatalytic performance for the degradation of methylene blue under solar light irradiation. - Abstract: In this work, molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) composite hydrogel was prepared via a one-step hydrothermal method. The morphology and structure of the as-prepared hydrogels with different proportions of MoS{sub 2} and GO were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical impedance spectra and UV–vis absorption spectroscopy. The photocatalytic performance of MoS{sub 2}–GO nanocomposites was studied toward the degradation of methylene blue (MB). Results showed that the MoS{sub 2}–GO nanocomposites exhibited improved photocatalytic activities in the degradation of MB with a maximum degradation rate of 99% under solar lights irradiation within 60 min. The synthesized MoS{sub 2}–GO composite hydrogel possesses great potential toward the development of newly synthesizable catalysts in the field of organic degradation in water.

  5. Highly efficient and simplified phosphorescence white organic light-emitting diodes based on synthesized deep-blue host and orange emitter

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Ja Ryong; Lee, Seok Jae; Hyung, Gun Woo; Kim, Bo Young; Lee, Dong Hyung [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Woo Young [Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Kum Hee [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@hongik.ac.kr [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of)

    2013-10-01

    The authors have demonstrated a highly efficient and stable phosphorescent white organic light-emitting diode (WOLED), which has been achieved by doping only one orange phosphorescent emitter, Bis(5-benzoyl-2-(4-fluorophenyl)pyridinato-C,N)iridium(III) acetylacetonate into an appropriate deep blue phosphorescent host, 4,4'-bis(4-(triphenylsilyl)phenyl)-1,1'-binaphthyl as an emitting layer (EML). The WOLED has been achieved by effective confinement of triplet excitons to emit a warm white color. The optimized WOLED, with a simple structure as a hole transporting layer-EML-electron transporting layer, showed a maximum luminous efficiency of 22.38 cd/A, a maximum power efficiency of 12.01 lm/W, a maximum external quantum efficiency of 7.32%, and CIEx,y coordinates of (0.38,0.42) at 500 cd/m{sup 2}, respectively. - Highlights: • Highly efficient phosphorescent white organic light-emitting diode (WOLED) • Single emitting layer consists of synthesized deep blue host and orange emitter • The WOLED with high EL efficiencies due to efficient triplet exciton confinement.

  6. Efficient degradation of Methylene Blue dye over highly reactive Cu doped strontium titanate (SrTiO3) nanoparticles photocatalyst under visible light.

    Science.gov (United States)

    Rahman, Qazi Inamur; Ahmad, Musheer; Misra, Sunil Kumar; Lohani, Minaxi

    2012-09-01

    Visible light induced photocatalysts of Cu doped SrTiO3 (Cu/SrTiO3) nanoparticles with the size -60-75 nm were prepared via facile sol-gel method. The morphological, optical, crystalline properties and compositions of synthesized Cu/SrTiO3 nanoparticles were thoroughly characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), ultra violet-visible spectroscopy (UV-Vis) and energy dispersive X-ray (EDX). A significant red shift in the UV-diffused reflectance spectrum was observed and the absorption edge shifted to visible region by the Cu doping. Surprisingly, the band gap of SrTiO3 was changed from 3.2 eV drop to 2.96 eV. The photocatalytic activity of the synthesized Cu/SrTiO3 nanoparticles was demonstrated for the degradation of Methylene Blue dye under visible light irradiation. The formation of new acceptor region in Cu/SrTiO3 was responsible for high photocatalytic activity of Cu/SrTiO3 nanoparticles. The results showed that the Methylene Blue dye was degraded by -66% within time span of 2 h over the Cu/SrTiO3 nanoparticles. This dye degradation reaction followed the Langmuir-Hinshelwood kinetics and also exhibited first order reaction rate. The calculated rate constant for the degradation reaction following first order kinetics was k = 0.0016 min(-1).

  7. Synthesis, photoluminescence and forensic applications of blue light emitting azomethine-zinc (II complexes of bis(salicylidenecyclohexyl-1,2-diamino based organic ligands

    Directory of Open Access Journals (Sweden)

    M. Srinivas

    2017-06-01

    Full Text Available Various azomethine-zinc(II complexes (3a-c of bis(salicylidenecyclohexyl-1,2-diamino organic ligands were synthesized by one pot reaction of salicylaldehydes/2-hydroxy-1-naphthaldehyde (2 eq, cyclohexyl-1,2-diamine (1 eq and zinc acetate (1 eq in methanol solvent at reflux temperature. The synthesized complexes were characterized by FTIR, 1H NMR, and SEM. Their photophysical properties such as Photoluminescence (PL and Diffused Reflectance Spectra (DRS were studied. PL studies revealed that the emission peaks of the complexes in both solution and solid states appeared to occur at 395–600 nm and emitted blue light. The band gap energies determined from DRS were 2.98 eV (3a, 2.91 eV (3b, and 2.73 eV (3c. Based on these results, we ascertain that these Zn(II complexes can serve as a suitable non-dopant blue light emitting compound for flat panel display applications. Latent fingerprint detection study indicated that the powder compounds show good adhesion and finger ridge details without background staining. The demonstrated method can be applied to detect fingerprints on all types of smooth surfaces.

  8. Synthesis and characterization of pure and Li⁺ activated Alq₃ complexes for green and blue organic light emitting diodes and display devices.

    Science.gov (United States)

    Bhagat, S A; Borghate, S V; Kalyani, N Thejo; Dhoble, S J

    2014-08-01

    Pure and Li(+)-doped Alq3 complexes were synthesized by simple precipitation method at room temperature, maintaining the stoichiometric ratio. These complexes were characterized by X-ray diffraction, ultraviolet-visible absorption and Fourier transform infrared and photoluminescence (PL) spectra. X-ray diffraction analysis reveals the crystalline nature of the synthesized complexes, while Fourier transform infrared spectroscopy confirm the molecular structure, the completion of quinoline ring formation and presence of quinoline structure in the metal complex. Ultraviolet-visible and PL spectra revealed that Li(+) activated Alq3 complexes exhibit the highest intensity in comparison to pure Alq3 phosphor. Thus, Li(+) enhances PL emission intensity when doped into Alq3 phosphor. The excitation spectra lie in the range of 383-456 nm. All the synthesized complexes other than Liq give green emission, while Liq gives blue emission with enhanced intensity. Thus, he synthesized phosphors are the best suitable candidates for green- and blue-emitting organic light emitting diode, PL liquid-crystal display and solid-state lighting applications. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Utilization of visible to NIR light energy by Yb"+"3, Er"+"3 and Tm"+"3 doped BiVO_4 for the photocatalytic degradation of methylene blue

    International Nuclear Information System (INIS)

    Regmi, Chhabilal; Kshetri, Yuwaraj K.; Ray, Schindra Kumar; Pandey, Ramesh Prasad; Lee, Soo Wohn

    2017-01-01

    Highlights: • Lanthanide doped BiVO_4 as highly efficient upconversion and photocatalytic material. • Well defined beads like morphology for better photocatalytic activity. • Effective utilization of NIR and visible light for efficient photocatalytic degradation of methylene blue. • Nontoxic to human cells, potential for application in biological fields. - Abstract: Lanthanide-doped BiVO_4 semiconductors with efficient photocatalytic activities over a broad range of the solar light spectrum have been synthesized by the microwave hydrothermal method using ethylenediaminetetraacetic acid (EDTA). The structural, morphological, and optical properties of the as-synthesized samples were evaluated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray powder diffraction (XRD), Raman spectroscopy, FT-IR spectroscopy, UV–vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The chemical compositions were analyzed by X-ray photoelectron spectroscopy (XPS). The toxicity of the samples was measured using Mus musculus skin melanoma cells (B16-F10 (ATCC"® CRL-6475™)) and were found to be nontoxic for human cells. The photocatalytic efficiency of the prepared samples was evaluated by methylene blue (MB) degradation. The best photocatalytic activity was shown by BiVO_4 with 6:3:3 mol percentage of Yb"+"3:Er"+"3:Tm"+"3 in all solar light spectrum. The synthesized samples possess low band gap energy and a hollow structure suitable for the better photocatalytic activity. The observed NIR photoactivity supports that the upconversion mechanism is involved in the overall photocatalytic process. Therefore, this approach provides a better alternative upconversion material for integral solar light absorption.

  10. Acute short-term dim light exposure can lower muscle strength endurance

    OpenAIRE

    Arnold G. Nelson; Joke Kokkonen; Megan Mickenberg

    2015-01-01

    Background: Since it has been shown that spending 18 h under dim light conditions can result in reduced handgrip endurance, it was questioned whether or not a shorter exposure to dim light (i.e., 1 h) would have similar influence upon muscular endurance. Therefore this study compared the number of weighted knee extension lifts that could be done after spending 1 h in either dim or bright light. Methods: Participants (5 women, 11 men, college students 19–26 years) performed knee extension l...

  11. Controlled patterns of daytime light exposure improve circadian adjustment in simulated night work.

    Science.gov (United States)

    Dumont, Marie; Blais, Hélène; Roy, Joanie; Paquet, Jean

    2009-10-01

    Circadian misalignment between the endogenous circadian signal and the imposed rest-activity cycle is one of the main sources of sleep and health troubles in night shift workers. Timed bright light exposure during night work can reduce circadian misalignment in night workers, but this approach is limited by difficulties in incorporating bright light treatment into most workplaces. Controlled light and dark exposure during the daytime also has a significant impact on circadian phase and could be easier to implement in real-life situations. The authors previously described distinctive light exposure patterns in night nurses with and without circadian adaptation. In the present study, the main features of these patterns were used to design daytime light exposure profiles. Profiles were then tested in a laboratory simulation of night work to evaluate their efficacy in reducing circadian misalignment in night workers. The simulation included 2 day shifts followed by 4 consecutive night shifts (2400-0800 h). Healthy subjects (15 men and 23 women; 20-35 years old) were divided into 3 groups to test 3 daytime light exposure profiles designed to produce respectively a phase delay (delay group, n=12), a phase advance (advance group, n=13), or an unchanged circadian phase (stable group, n=13). In all 3 groups, light intensity was set at 50 lux during the nights of simulated night work. Salivary dim light melatonin onset (DLMO) showed a significant phase advance of 2.3 h (+/-1.3 h) in the advance group and a significant phase delay of 4.1 h (+/-1.3 h) in the delay group. The stable group showed a smaller but significant phase delay of 1.7 h (+/-1.6 h). Urinary 6-sulfatoxymelatonin (aMT6s) acrophases were highly correlated to salivary DLMOs. Urinary aMT6s acrophases were used to track daily phase shifts. They showed that phase shifts occurred rapidly and differed between the 3 groups by the 3rd night of simulated night work. These results show that significant phase shifts can

  12. Long-lived hot-carrier light emission and large blue shift in formamidinium tin triiodide perovskites

    OpenAIRE

    Fang, Hong-Hua; Adjokatse, Sampson; Shao, Shuyan; Even, Jacky; Loi, Maria Antonietta

    2018-01-01

    A long-lived hot carrier population is critical in order to develop working hot carrier photovoltaic devices with efficiencies exceeding the Shockley-Queisser limit. Here, we report photoluminescence from hot-carriers with unexpectedly long lifetime (a few ns) in formamidinium tin triiodide. An unusual large blue shift of the time-integrated photoluminescence with increasing excitation power (150 meV at 24 K and 75 meV at 293 K) is displayed. On the basis of the analysis of energy-resolved an...

  13. Effect of sub-acute exposure to bonny light crude oil on plasma ...

    African Journals Online (AJOL)

    Effect of sub-acute exposure to bonny light crude oil on plasma biochemistry and liver histopathology of albino rat. Christopher Efe Oritseweyinmi Ikanone, Oluseyi Adeboye Akinloye, Regina Ngozi Ugbaja, Samuel Olatunbosun Omotainse, Olusola Lawrence Ajayi, Tolumide Michael Shopein ...

  14. Modifications of γ-ray sensitivity of bacterial membranes by pre-exposure to light

    International Nuclear Information System (INIS)

    Misiti-Dorello, P.; Cancelliere, G.; De Martino, G.; Quintilini, M.

    1976-01-01

    The exposure of E. coli B/r cells to ultraviolet or to visible light prior to irradiation with γ-rays modifies the sensitivity of the cell membrane to radiation damage responsible for the intracellular K + content. Exposure of bacterial cells to sublethal doses of UV radiation increases their sensitivity to γ-induced membrane damage, while exposure to visible light has the opposite effect. In combined exposures, the visible light, either given before or after the UV always produces a strong photoprotective effect. In either case, the photosensitizing effect of UV is completely suppressed. The photoprotection decays with time if cell suspensions are left in the dark before γ-irradiation. At O 0 C, the half-life of the photoprotective effect is 25 min at pH 7 and 100 min at pH 7.5. The decay is due to the presence of oxygen. The light band responsible for the induction of photoprotection has been estimated to lie in the wavelenght region between 540 and 580 nm. (orig./MG) [de

  15. Prenatal light exposure affects early feather-pecking behaviour in the domestic chick

    NARCIS (Netherlands)

    Riedstra, B; Groothuis, TGG

    Recently we proposed that early feather pecking is a form of social exploration. Social recognition, important for exploration, is a lateralized function in the domestic chick. Lateralization of functions can be influenced by light exposure late in embryonic development. Therefore, we investigated

  16. Natural light exposure, healthy elderly people and sleep : a field study

    NARCIS (Netherlands)

    Aarts, M.P.J.; Schoutens, A.M.C.; Stapel, J.C.

    2006-01-01

    Among 14 independently living, mobile and healthy elderly people in The Netherlands was conducted to see whether exposure duration of high intensity, natural, light is related to sleep quality, and more general the amplitude of the sleep-wake cycle. The elderly wore for 5 consecutive days in summer

  17. Nighttime dim light exposure alters the responses of the circadian system.

    Science.gov (United States)

    Shuboni, D; Yan, L

    2010-11-10

    The daily light dark cycle is the most salient entraining factor for the circadian system. However, in modern society, darkness at night is vanishing as light pollution steadily increases. The impact of brighter nights on wild life ecology and human physiology is just now being recognized. In the present study, we tested the possible detrimental effects of dim light exposure on the regulation of circadian rhythms, using CD1 mice housed in light/dim light (LdimL, 300 lux:20 lux) or light/dark (LD, 300 lux:1 lux) conditions. We first examined the expression of clock genes in the suprachiasmatic nucleus (SCN), the locus of the principal brain clock, in the animals of the LD and LdimL groups. Under the entrained condition, there was no difference in PER1 peak expression between the two groups, but at the trough of the PER 1 rhythm, there was an increase in PER1 in the LdimL group, indicating a decrease in the amplitude of the PER1 rhythm. After a brief light exposure (30 min, 300 lux) at night, the light-induced expression of mPer1 and mPer2 genes was attenuated in the SCN of LdimL group. Next, we examined the behavioral rhythms by monitoring wheel-running activity to determine whether the altered responses in the SCN of LdimL group have behavioral consequence. Compared to the LD controls, the LdimL group showed increased daytime activity. After being released into constant darkness, the LdimL group displayed shorter free-running periods. Furthermore, following the light exposure, the phase shifting responses were smaller in the LdimL group. The results indicate that nighttime dim light exposure can cause functional changes of the circadian system, and suggest that altered circadian function could be one of the mechanisms underlying the adverse effects of light pollution on wild life ecology and human physiology. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes

    International Nuclear Information System (INIS)

    Karabourniotis, G.; Bornman, J.F.

    1999-01-01

    Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development. (author)

  19. White light generation from YAG/YAM:Ce{sup 3+}, Pr{sup 3+}, Cr{sup 3+} nanophosphors mixed with a blue dye under 340 nm excitation

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, J. [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); Diaz-Torres, L.A [Centro de Investigaciones en Optica, A.P. 1-948, León, Gto 37150, México (Mexico); Torres, A. [Universidad Autónoma de Nuevo León, A.P. 126-F, Monterrey, NL 66450, México (Mexico); Salas, P. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Juriquilla, Qro. 76000, México (Mexico); Meza, O. [Benemérita Universidad Autónoma de Puebla, 4 Sur 104 Centro Historico, 72000 Puebla, México (Mexico)

    2014-10-15

    The structural and luminescent properties of Y{sub 3}Al{sub 5}O{sub 12}/Y{sub 4}Al{sub 2}O{sub 9}:Ce{sup 3+}(0.1%)–Pr{sup 3+}(0.1%) –Cr{sup 3+} (trace impurities) nanophosphors synthesized by a simple hydrothermal method were studied. The crystalline phase was composed of Yttrium Aluminum Garnet (YAG) and Yttrium Aluminum Monoclinic (YAM) depending on the ammonia concentration and annealing temperature. Ammonia increased the stabilization of YAG from 55 wt% to 63 wt% in the samples annealed at 900 °C, and an increment of 83% of the overall emission under 460 nm excitation was observed. Quenching of the emitted signal after annealing at 1100 °C was observed in spite of single YAG crystalline phase stabilization, due to the formation of Ce{sup 4+}, Pr{sup 4+}, and color centers. In addition to the green–yellow emission from Ce{sup 3+}, all samples present a broad red emission band produced by the relaxations from the broad band {sup 4}T{sub 2} toward the {sup 4}A{sub 2} energy level of Cr{sup 3+} impurities, under 340 nm excitation. By taking advantage of this broad green–yellow–red emission and using a blue dye, white light with CIE coordinates of (0.30, 0.36) under 340 nm excitation was produced. - Highlights: • YAG/YAM:Ce{sup 3+}, Pr{sup 3+}, Cr{sup 3+} nanophosphors were synthesized with a hydrothermal method. • Ammonia introduced during the synthesis increased the emission of nanophosphors. • White light was obtained by combining the emissions of a blue dye and nanophosphors. • The CIE coordinates for this white light are (0.30, 0.36)

  20. Light exposure influences the diurnal oscillation of gut microbiota in mice.

    Science.gov (United States)

    Wu, Guangyan; Tang, Wenli; He, Yan; Hu, Jingjuan; Gong, Shenhai; He, Zhanke; Wei, Guoquan; Lv, Liyi; Jiang, Yong; Zhou, Hongwei; Chen, Peng

    2018-05-03

    The gut microbiota exhibit diurnal compositional and functional oscillations that influence the host homeostasis. However, the upstream factors that affect the microbial oscillations remain elusive. Here, we focused on the potential impact of light exposure, the main factor that affects the host circadian oscillation, on the diurnal oscillations of intestinal microflora to explore the upstream factor that governs the fluctuations of the gut microbes. The gut microbiota of the mice that were underwent regular light/dark (LD) cycles exhibited a robust rhythm at both compositional and functional level, in all parts of the intestine. Comparably, constant darkness (DD) led to the loss of the rhythmic oscillations in almost all parts of the intestine. Additionally, the abundance of Clostridia in DD conditions was dramatically enhanced in the small intestine. Our data indicated light exposure is the upstream factor that governs the regular diurnal fluctuations of gut microbiota in vivo. Copyright © 2018. Published by Elsevier Inc.

  1. Visible light-induced photocatalytic degradation of Reactive Blue-19 over highly efficient polyaniline-TiO2 nanocomposite: a comparative study with solar and UV photocatalysis.

    Science.gov (United States)

    Kalikeri, Shankramma; Kamath, Nidhi; Gadgil, Dhanashri Jayant; Shetty Kodialbail, Vidya

    2018-02-01

    Polyaniline-TiO 2 (PANI-TiO 2 ) nanocomposite was prepared by in situ polymerisation method. X-ray diffractogram (XRD) showed the formation of PANI-TiO 2 nanocomposite with the average crystallite size of 46 nm containing anatase TiO 2 . The PANI-TiO 2 nanocomposite consisted of short-chained fibrous structure of PANI with spherical TiO 2 nanoparticles dispersed at the tips and edge of the fibres. The average hydrodynamic diameter of the nanocomposite was 99.5 nm. The band gap energy was 2.1 eV which showed its ability to absorb light in the visible range. The nanocomposite exhibited better visible light-mediated photocatalytic activity than TiO 2 (Degussa P25) in terms of degradation of Reactive Blue (RB-19) dye. The photocatalysis was favoured under initial acidic pH, and complete degradation of 50 mg/L dye could be achieved at optimum catalyst loading of 1 g/L. The kinetics of degradation followed the Langmuir-Hinshelhood model. PANI-TiO 2 nanocomposite showed almost similar photocatalytic activity under UV and visible light as well as in the solar light which comprises of radiation in both UV and visible light range. Chemical oxygen demand removal of 86% could also be achieved under visible light, confirming that simultaneous mineralization of the dye occurred during photocatalysis. PANI-TiO 2 nanocomposites are promising photocatalysts for the treatment of industrial wastewater containing RB-19 dye.

  2. Exposure to bright light for several hours during the daytime lowers tympanic temperature.

    Science.gov (United States)

    Aizawa, S; Tokura, H

    1997-11-01

    The present study investigates the effect on thympanic temperature of exposure to different light intensities for several hours during the daytime. Nine healthy young adult volunteers (two male, seven female) were exposed to bright light of 4000 lx or dim light of 100 lx during the daytime from 0930 to 1800 hours; the light condition was then kept at 100 lx for a further hour. Tympanic temperature was measured continuously at a neutral condition (28 degrees C, 60% relative humidity) from 1000 to 1800 hours. Urinary samples were collected from 1100 to 1900 hours every 2 h, and melatonin excretion rate was measured by enzyme immunoassay. Of nine subjects, six showed clearly lower tympanic temperatures in the bright compared with the dim condition from 1400 to 1800 hours. Average tympanic temperatures were significantly lower in the bright than in the dim condition from 1645 to 1800 hours. Melatonin excretion rate tended to be higher in the bright than in the dim condition. It was concluded that exposure to bright light of 4000 lx during the daytime for several hours could reduce tympanic temperature, compared with that measured in dim light of 100 lx.

  3. Exposure to bright light for several hours during the daytime lowers tympanic temperature

    Science.gov (United States)

    Aizawa, Seika; Tokura, H.

    The present study investigates the effect on thympanic temperature of exposure to different light intensities for several hours during the daytime. Nine healthy young adult volunteers (two male, seven female) were exposed to bright light of 4000 lx or dim light of 100 lx during the daytime from 0930 to 1800 hours; the light condition was then kept at 100 lx for a further hour. Tympanic temperature was measured continuously at a neutral condition (28° C, 60% relative humidity) from 1000 to 1800 hours. Urinary samples were collected from 1100 to 1900 hours every 2 h, and melatonin excretion rate was measured by enzyme immunoassay. Of nine subjects, six showed clearly lower tympanic temperatures in the bright compared with the dim condition from 1400 to 1800 hours. Average tympanic temperatures were significantly lower in the bright than in the dim condition from 1645 to 1800 hours. Melatonin excretion rate tended to be higher in the bright than in the dim condition. It was concluded that exposure to bright light of 4000 lx during the daytime for several hours could reduce tympanic temperature, compared with that measured in dim light of 100 lx.

  4. Origin of a counterintuitive yellow light-emitting electrochemical cell based on a blue-emitting heteroleptic copper(i) complex.

    Science.gov (United States)

    Weber, Michael D; Garino, Claudio; Volpi, Giorgio; Casamassa, Enrico; Milanesio, Marco; Barolo, Claudia; Costa, Rubén D

    2016-06-07

    This work provides the synthesis, structural characterization, electrochemical and photophysical features, as well as the application in light-emitting electrochemical cells (LECs) of a novel heteroleptic copper(i) complex - [Cu(impy)(POP)][PF6], where impy is 3-(2-methoxyphenyl)-1-(pyridine-2-yl)imidazo[1,5-a]pyridine and POP is bis{2-(diphenylphosphanyl)phenyl}ether. This compound shows blue photoluminescence (PL, λ = 450 nm) in solution and solid-state and excellent redox stability. Despite these excellent features, the electroluminescence (EL) response is located at ∼550 nm. Although the EL spectrum of LECs is typically red-shifted compared to the PL of the electroluminescent material, a shift of ca. 100 nm represents the largest one reported in LECs. To date, the large shift phenomena have been attributed to (i) a change in the nature of the lowest emitting state due to a concentration effect of the films, (ii) a reversible substitution of the ligands due to the weak coordination to the Cu(i), and (iii) a change in the distribution of the excited states due to polarization effects. After having discarded these along with others like the irreversible degradation of the emitter during device fabrication and/or under operation conditions, driving conditions, active layer composition, and changes in the excited states under different external electrical stimuli, we attribute the origin of this unexpected shift to a lack of a thermally activated delayed fluorescence (TADF) process due to the solely ligand-centered character of the excited states. As such, the lack of a charge transfer character in the excited states leads to a blue-fluorescence and yellow-phosphorescence photo- and electro-responses, respectively. This corroborates recent studies focused on the design of TADF for heteroleptic copper(i) complexes. Overall, this work is a clear insight into the design of new copper(i) complexes towards the preparation of blue LECs, which are still unexplored.

  5. Luminescent properties of Mg3Ca3(PO4)4: Eu2+ blue-emitting phosphor for white light emitting diodes

    International Nuclear Information System (INIS)

    Li Yinqun; Deng Degang; Wang Qian; Li Gaofeng; Hua Youjie; Jia Guohua; Huang Lihui; Zhao Shilong; Wang Huanping; Li Chenxia; Xu Shiqing

    2012-01-01

    A blue-emitting phosphor, Eu 2+ -activated Mg 3 Ca 3 (PO 4 ) 4 phosphor was synthesized by conventional solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the phase formation. Photoluminescence (PL) results showed that Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ could be efficiently excited by UV–visible light from 250 to 430 nm, which matched well with the emission wavelengths of near-UV and UV LED chips. The effects of the doped-Eu 2+ concentration in Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ on the PL were also investigated. The result reveals that Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ is a potential blue-emitting phosphor for white LEDs. - Graphical Abstract: The excitation spectra show a broad peak from 250 to 430 nm, which means Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor can be suitable for application in white LEDs excited by the near-UV and UV LEDs. The emission spectrum peaked at 456 nm with the full-width half-maximum (FWHM) of 102 nm is attributed to the 4f 6 5d 1 –4f 7 transition of the Eu 2+ ion. The asymmetric emission spectra show that Eu 2+ has more one emission center in Mg 3 Ca 3 (PO 4 ) 4 , which can be deconvoluted into at least four Gaussian components peaked at 423, 446, 483 and 510 nm. Highlights: ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor could be effectively excited by UV chips (360–430 nm). ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor is a potential blue-emitting phosphor for white LEDs. ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor shows a broadband emission.

  6. Long-lived hot-carrier light emission and large blue shift in formamidinium tin triiodide perovskites.

    Science.gov (United States)

    Fang, Hong-Hua; Adjokatse, Sampson; Shao, Shuyan; Even, Jacky; Loi, Maria Antonietta

    2018-01-16

    A long-lived hot carrier population is critical in order to develop working hot carrier photovoltaic devices with efficiencies exceeding the Shockley-Queisser limit. Here, we report photoluminescence from hot-carriers with unexpectedly long lifetime (a few ns) in formamidinium tin triiodide. An unusual large blue shift of the time-integrated photoluminescence with increasing excitation power (150 meV at 24 K and 75 meV at 293 K) is displayed. On the basis of the analysis of energy-resolved and time-resolved photoluminescence, we posit that these phenomena are associated with slow hot carrier relaxation and state-filling of band edge states. These observations are both important for our understanding of lead-free hybrid perovskites and for an eventual future development of efficient lead-free perovskite photovoltaics.

  7. The colour-tuning effect of 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline in blue-red organic light-emitting devices

    International Nuclear Information System (INIS)

    Lin Jian; Xia, Yi-Jie; Tang Chao; Yin Kun; Zhong Gaoyu; Ni Gang; Peng Bo; Hou Xiaoyuan; Gan Fuxi; Huang Wei

    2007-01-01

    This paper reports the fabrication and measurement of organic light-emitting devices comprised of indium-tin-oxide (ITO)/4,4',4-prime-tris(N-carbazolyl)-triphenylamine (TCTA, 8 nm)/2-pyrenyl-9-phenyl-9-pyrenylfluorene(2P9PPF, 30 nm)/ bathocuproine (BCP, with different thickness)/Alq 3 : DCJTB (DCJTB = 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7- tetramethyljulolidyl-9-enyl)-4H-pyran, Alq 3 = tris(8-hydroxyquinolino) aluminium(III), 2% in mass ratio, 30 nm)/Mg : Ag(250 nm). The dependence of electroluminescence (EL) spectra on the BCP layer thickness and operating voltage has been investigated quantitatively. It is shown that the emission colour of the devices changes from red to blue at 8 V when the BCP layer thickness changes from 1 to 10 nm. The emission colour of the devices also varies with the applying voltage even in a given device. The ratio of blue emission originating from 2P9PPF to the red emission originating from DCJTB increases with the applying voltage. Based on the hole blocking effect of the BCP layer, we deduced the dependence of this ratio on the BCP layer thickness and simulated the experimental result well. It is also proposed that the variation of the EL spectrum with the voltage can be attributed to the varying hole blocking effect under the varying electric field, which resulted in a recombination zone shift, and the exciton dissociation effect in the electric field

  8. Modified solvothermal synthesis of cobalt ferrite (CoFe2O4) magnetic nanoparticles photocatalysts for degradation of methylene blue with H2O2/visible light