40 CFR 86.1717-01 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. 86.1717-01 Section 86.1717-01 Protection of... diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. (a) The provisions of § 86...

40 CFR 86.1717-99 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. 86.1717-99 Section 86.1717-99 Protection of... diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. (a) The provisions of § 86...

40 CFR 86.1717-01 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. 86.1717-01 Section 86.1717-01 Protection of... diagnostic system for 1999 and later light-duty vehicles and light-duty trucks. (a) The provisions of § 86...

Method and Apparatus for Improved Spatial Light Modulation

NASA Technical Reports Server (NTRS)

Soutar, Colin (Inventor); Juday, Richard D. (Inventor)

2000-01-01

A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain the optical processing objective.

Method and Apparatus for Improved Spatial Light Modulation

NASA Technical Reports Server (NTRS)

Colin, Soutar (Inventor); Juday, Richard D. (Inventor)

1999-01-01

A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain die optical processing objective.

Near-infrared light-controlled systems for gene transcription regulation, protein targeting and spectral multiplexing.

PubMed

Redchuk, Taras A; Kaberniuk, Andrii A; Verkhusha, Vladislav V

2018-05-01

Near-infrared (NIR, 740-780 nm) optogenetic systems are well-suited to spectral multiplexing with blue-light-controlled tools. Here, we present two protocols, one for regulation of gene transcription and another for control of protein localization, that use a NIR-responsive bacterial phytochrome BphP1-QPAS1 optogenetic pair. In the first protocol, cells are transfected with the optogenetic constructs for independently controlling gene transcription by NIR (BphP1-QPAS1) and blue (LightOn) light. The NIR and blue-light-controlled gene transcription systems show minimal spectral crosstalk and induce a 35- to 40-fold increase in reporter gene expression. In the second protocol, the BphP1-QPAS1 pair is combined with a light-oxygen-voltage-sensing (LOV) domain-based construct into a single optogenetic tool, termed iRIS. This dual-light-controllable protein localization tool allows tridirectional protein translocation among the cytoplasm, nucleus and plasma membrane. Both procedures can be performed within 3-5 d. Use of NIR light-controlled optogenetic systems should advance basic and biomedical research.

Illumination control apparatus for compensating solar light

NASA Technical Reports Server (NTRS)

Owens, L. J. (Inventor)

1978-01-01

An illumination control apparatus is presented for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light. The apparatus maintains a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with a switch means for selectively energizing said light source. An actuator means for controlling the on-off operation of the switch means is connected to a light sensor which responses to the illumination level of the interior space. A limit switch carried adjacent to the actuator limits the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

Effects of light quality on the accumulation of phytochemicals in vegetables produced in controlled environments: a review.

PubMed

Bian, Zhong Hua; Yang, Qi Chang; Liu, Wen Ke

2015-03-30

Phytochemicals in vegetables are important for human health, and their biosynthesis, metabolism and accumulation are affected by environmental factors. Light condition (light quality, light intensity and photoperiod) is one of the most important environmental variables in regulating vegetable growth, development and phytochemical accumulation, particularly for vegetables produced in controlled environments. With the development of light-emitting diode (LED) technology, the regulation of light environments has become increasingly feasible for the provision of ideal light quality, intensity and photoperiod for protected facilities. In this review, the effects of light quality regulation on phytochemical accumulation in vegetables produced in controlled environments are identified, highlighting the research progress and advantages of LED technology as a light environment regulation tool for modifying phytochemical accumulation in vegetables. © 2014 Society of Chemical Industry.

Modeling of lighting behaviour of a hybrid lighting system in inner spaces of Building of Electrical Engineering

NASA Astrophysics Data System (ADS)

Amado, L.; Osma, G.; Villamizar, R.

2016-07-01

This paper presents the modelling of lighting behaviour of a hybrid lighting system - HLS in inner spaces for tropical climate. HLS aims to mitigate the problem of high electricity consumption used by artificial lighting in buildings. These systems integrate intelligently the daylight and artificial light through control strategies. However, selection of these strategies usually depends on expertise of designer and of available budget. In order to improve the selection process of the control strategies, this paper analyses the Electrical Engineering Building (EEB) case, initially modelling of lighting behaviour is established for the HLS of a classroom and an office. This allows estimating the illuminance level of the mixed lighting in the space, and energy consumption by artificial light according to different lighting control techniques, a control strategy based on occupancy and a combination of them. The model considers the concept of Daylight Factor (DF) for the estimating of daylight illuminance on the work plane for tropical climatic conditions. The validation of the model was carried out by comparing the measured and model-estimated indoor illuminances.

Quantum Control of Light and Matter: From the Macroscopic to the Nano Scale

DTIC Science & Technology

2016-02-02

navigation, and hybrid bio -graphene devices, incorporating enzymes positioned on graphene, for light-driven bio -fuel production with controlled...enzymatic rates. 15. SUBJECT TERMS Light-matter interactions; Quantum control; Slow light; Bose-Einstein condensates; Nano-science; Hybrid bio -nano...precise navigation. They also include hybrid bio -graphene devices incorporating enzymes positioned on graphene for dynamic control of enzymatic

Abnormal hypothalamic response to light in seasonal affective disorder.

PubMed

Vandewalle, Gilles; Hébert, Marc; Beaulieu, Catherine; Richard, Laurence; Daneault, Véronique; Garon, Marie-Lou; Leblanc, Jean; Grandjean, Didier; Maquet, Pierre; Schwartz, Sophie; Dumont, Marie; Doyon, Julien; Carrier, Julie

2011-11-15

Vulnerability to the reduction in natural light associated with fall/winter is generally accepted as the main trigger of seasonal affective disorder (SAD), whereas light therapy is a treatment of choice of the disorder. However, the relationship between exposure to light and mood regulation remains unclear. As compared with green light, blue light was shown to acutely modulate emotion brain processing in healthy individuals. Here, we investigated the impact of light on emotion brain processing in patients with SAD and healthy control subjects and its relationship with retinal light sensitivity. Fourteen symptomatic untreated patients with SAD (34.5 ± 8.2 years; 9 women) and 16 healthy control subjects (32.3 ± 7.7 years; 11 women) performed an auditory emotional task in functional magnetic resonance imaging during the fall/winter season, while being exposed to alternating blue and green monochromatic light. Scotopic and photopic retinal light sensitivities were then evaluated with electroretinography. Blue light enhanced responses to auditory emotional stimuli in the posterior hypothalamus in patients with SAD, whereas green light decreased these responses. These effects of blue and green light were not observed in healthy control subjects, despite similar retinal sensitivity in SAD and control subjects. These results point to the posterior hypothalamus as the neurobiological substrate involved in specific aspects of SAD, including a distinctive response to light and altered emotional responses. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Intelligent Traffic Light Based on PLC Control

NASA Astrophysics Data System (ADS)

Mei, Lin; Zhang, Lijian; Wang, Lingling

2017-11-01

The traditional traffic light system with a fixed control mode and single control function is contradicted with the current traffic section. The traditional one has been unable to meet the functional requirements of the existing flexible traffic control system. This paper research and develop an intelligent traffic light called PLC control system. It uses PLC as control core, using a sensor module for receiving real-time information of vehicles, traffic control mode for information to select the traffic lights. Of which control mode is flexible and changeable, and it also set the countdown reminder to improve the effectiveness of traffic lights, which can realize the goal of intelligent traffic diversion, intelligent traffic diversion.

System and method for assaying radiation

DOEpatents

DiPrete, David P; Whiteside, Tad; Pak, Donald J; DiPrete, Cecilia C

2013-11-12

A system for assaying radiation includes a sample holder configured to hold a liquid scintillation solution. A photomultiplier receives light from the liquid scintillation solution and generates a signal reflective of the light. A control circuit biases the photomultiplier and receives the signal from the photomultiplier reflective of the light. A light impermeable casing surrounds the sample holder, photomultiplier, and control circuit. A method for assaying radiation includes placing a sample in a liquid scintillation solution, placing the liquid scintillation solution in a sample holder, and placing the sample holder inside a light impermeable casing. The method further includes positioning a photomultiplier inside the light impermeable casing and supplying power to a control circuit inside the light impermeable casing.

Light exclusion influence on grape anthocyanin

USDA-ARS?s Scientific Manuscript database

This study contrasted the anthocyanins of investigational grape clusters that developed without light incidence (light-excluded), to those of control clusters that were shaded naturally beneath the vine canopy (control-shaded). Treatment grape clusters were light-excluded during ripening by opaque w...

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback

PubMed Central

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-01-01

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes. PMID:28208781

Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback.

PubMed

Liu, Haoting; Zhou, Qianxiang; Yang, Jin; Jiang, Ting; Liu, Zhizhen; Li, Jie

2017-02-09

An imaging sensor-based intelligent Light Emitting Diode (LED) lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs) are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes.

Effect of various infection-control methods for light-cure units on the cure of composite resins.

PubMed

Chong, S L; Lam, Y K; Lee, F K; Ramalingam, L; Yeo, A C; Lim, C C

1998-01-01

This study (1) compared the curing-light intensity with various barrier infection-control methods used to prevent cross contamination, (2) compared the Knoop hardness value of cured composite resin when various barrier control methods were used, and (3) correlated the hardness of the composite resin with the light-intensity output when different infection-control methods were used. The light-cure unit tips were covered with barriers, such as cellophane wrap, plastic gloves, Steri-shields, and finger cots. The control group had no barrier. Composite resins were then cured for each of the five groups, and their Knoop hardness values recorded. The results showed that there was significant statistical difference in the light-intensity output among the five groups. However, there was no significant statistical difference in the Knoop hardness values among any of the groups. There was also no correlation between the Knoop hardness value of the composite resin with the light-intensity output and the different infection-control methods. Therefore, any of the five infection-control methods could be used as barriers for preventing cross-contamination of the light-cure unit tip, for the light-intensity output for all five groups exceeded the recommended value of 300 W/m2. However, to allow a greater margin of error in clinical situations, the authors recommend that the plastic glove or the cellophane wrap be used to wrap the light-cure tip, since these barriers allowed the highest light-intensity output.

A Programmable Optical Stimulator for the Drosophila Eye.

PubMed

Chen, Xinping; Leon-Salas, Walter D; Zigon, Taylor; Ready, Donald F; Weake, Vikki M

2017-10-01

A programmable optical stimulator for Drosophila eyes is presented. The target application of the stimulator is to induce retinal degeneration in fly photoreceptor cells by exposing them to light in a controlled manner. The goal of this work is to obtain a reproducible system for studying age-related changes in susceptibility to environmental ocular stress. The stimulator uses light emitting diodes and an embedded computer to control illuminance, color (blue or red) and duration in two independent chambers. Further, the stimulator is equipped with per-chamber light and temperature sensors and a fan to monitor light intensity and to control temperature. An ON/OFF temperature control implemented on the embedded computer keeps the temperature from reaching levels that will induce the heat shock stress response in the flies. A custom enclosure was fabricated to house the electronic components of the stimulator. The enclosure provides a light-impermeable environment that allows air flow and lets users easily load and unload fly vials. Characterization results show that the fabricated stimulator can produce light at illuminances ranging from 0 to 16000 lux and power density levels from 0 to 7.2 mW/cm 2 for blue light. For red light the maximum illuminance is 8000 lux which corresponds to a power density of 3.54 mW/cm 2 . The fans and the ON/OFF temperature control are able to keep the temperature inside the chambers below 28.17°C. Experiments with white-eye male flies were performed to assess the ability of the fabricated simulator to induce blue light-dependent retinal degeneration. Retinal degeneration is observed in flies exposed to 8 hours of blue light at 7949 lux. Flies in a control experiment with no light exposure show no retinal degeneration. Flies exposed to red light for the similar duration and light intensity (8 hours and 7994 lux) do not show retinal degeneration either. Hence, the fabricated stimulator can be used to create environmental ocular stress using blue light.

Bumblebees Perform Well-Controlled Landings in Dim Light.

PubMed

Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

2016-01-01

To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position-behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active.

International lighting in controlled environments workshop: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-12-31

Lighting is a central and critical aspect of control in environmental research for plant research and is gaining recognition as a significant factor to control carefully for animal and human research. Thus this workshop was convened to reevaluate the technology that is available today and to work toward developing guidelines for the most effective use of lighting in controlled environments with emphasis on lighting for plants but also to initiate interest in the development of improved guidelines for human and animal research. There are a number of established guidelines for lighting in human and animal environments. Development of new lightingmore » guidelines is necessary for three reasons: (1) recent scientific discoveries show that in addition to supporting the sensation of vision, light has profound nonvisual biological and behavioral effects in both animals and humans; (2) federal regulations (EPACT 1992) are requiring all indoor environments to become more energy efficient with a specific emphasis on energy conservation in lighting; (3) lighting engineers and manufacturers have developed a wealth of new light sources and lighting products that can be applied in animal and human environments. The workshop was aimed at bringing together plant scientists and physical scientists to interact in the discussions. It involved participation of biological scientists involved in studying mechanisms of light reactions and those involved in utilizing lighting for production of plants and maintenance of animals in controlled environments. It included participation of physical scientists from universities and government involved in research as well as those from industry involved in producing lamps and in construction of controlled growth facilities. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.« less

Outdoor Lighting Ordinances

NASA Astrophysics Data System (ADS)

Davis, S.

2004-05-01

A principal means to prevent poor exterior lighting practices is a lighting control ordinance. It is an enforceable legal restriction on specific lighting practices that are deemed unacceptable by the government body having jurisdiction. Outdoor lighting codes have proven to be effective at reducing polluting and trespassing light. A well written exterior lighting code will permit all forms of necessary illumination at reasonable intensities, but will demand shielding and other measures to prevent trespass and light pollution. A good code will also apply to all forms of outdoor lighting, including streets, highways, and exterior signs, as well as the lighting on dwellings, commercial and industrial buildings and building sites. A good code can make exceptions for special uses, provided it complies with an effective standard. The IDA Model Lighting Ordinance is a response to these requests. It is intended as an aid to communities that are seeking to take control of their outdoor lighting, to "take back the night" that is being lost to careless and excessive use of night lighting.

A light-controlled cell lysis system in bacteria.

PubMed

Wang, Geyi; Lu, Xin; Zhu, Yisha; Zhang, Wei; Liu, Jiahui; Wu, Yankang; Yu, Liyang; Sun, Dongchang; Cheng, Feng

2018-05-08

Intracellular products (e.g., insulin), which are obtained through cell lysis, take up a big share of the biotech industry. It is often time-consuming, laborious, and environment-unfriendly to disrupt bacterial cells with traditional methods. In this study, we developed a molecular device for controlling cell lysis with light. We showed that intracellular expression of a single lysin protein was sufficient for efficient bacterial cell lysis. By placing the lysin-encoding gene under the control of an improved light-controlled system, we successfully controlled cell lysis by switching on/off light: OD 600 of the Escherichia coli cell culture was decreased by twofold when the light-controlled system was activated under dark condition. We anticipate that our work would not only pave the way for cell lysis through a convenient biological way in fermentation industry, but also provide a paradigm for applying the light-controlled system in other fields of biotech industry.

Light Control of Insulin Release and Blood Glucose Using an Injectable Photoactivated Depot.

PubMed

Sarode, Bhagyesh R; Kover, Karen; Tong, Pei Y; Zhang, Chaoying; Friedman, Simon H

2016-11-07

In this work we demonstrate that blood glucose can be controlled remotely through light stimulated release of insulin from an injected cutaneous depot. Human insulin was tethered to an insoluble but injectable polymer via a linker, which was based on the light cleavable di-methoxy nitrophenyl ethyl (DMNPE) group. This material was injected into the skin of streptozotocin-treated diabetic rats. We observed insulin being released into the bloodstream after a 2 min trans-cutaneous irradiation of this site by a compact LED light source. Control animals treated with the same material, but in which light was blocked from the site, showed no release of insulin into the bloodstream. We also demonstrate that additional pulses of light from the light source result in additional pulses of insulin being absorbed into circulation. A significant reduction in blood glucose was then observed. Together, these results demonstrate the feasibility of using light to allow for the continuously variable control of insulin release. This in turn has the potential to allow for the tight control of blood glucose without the invasiveness of insulin pumps and cannulas.

Portable lamp with dynamically controlled lighting distribution

DOEpatents

Siminovitch, Michael J.; Page, Erik R.

2001-01-01

A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) arranged vertically with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum insures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. The lighting system may be designed for the home, hospitality, office or other environments.

Developmental variation during seed germination and biochemical responses of Brassica rapa exposed to various colored lights.

PubMed

Nawaz, Tausif; Ahmad, Nisar; Ali, Shahid; Khan, Maaz; Fazal, Hina; Khalil, Shahid Akbar

2018-02-01

Light acting as elicitor or stress inducer, it plays a pivotal role in all developmental processes of plant providing necessary building blocks for growth and primary and secondary metabolites production. The main objective of the current study was to investigate the individual effect of colored lights on developmental processes and production of polyphenolics contents in Brassica rapa. In this study, the red and white lights (control) were found to be the most effective sources for seed germination (91%) in Brassica rapa. Similarly, red light enhanced radicle growth (102 mm), while green light suppressed radicle growth (60 mm) as compared to control (67 mm). The red light also promoted the plumule growth (50 mm) as compared to control (37 mm). The maximum biomass gain (67 mg) was observed under red light as compared to control (55 mg). Currently, the maximum total phenolics content (9.49 mg/g-DW) and phenolics production (379.616 mg/L) was observed under the influence of blue lights as compared to control (0.23 mg/g-DW and 8.91 mg/L). Similarly, the blue lights also enhanced the biosynthesis of total flavonoids content (2.2611 mg/g-DW) and flavonoids production (90.44 mg/L) as compared to control (0.0318 md/g-DW and 0.8268 mg/L). The current results represents that red and blue lights are the most effective sources for plantlets development and production of polyphenolics content in Brassica rapa. Copyright © 2018. Published by Elsevier B.V.

Method for controlling boiling point distribution of coal liquefaction oil product

DOEpatents

Anderson, R.P.; Schmalzer, D.K.; Wright, C.H.

1982-12-21

The relative ratio of heavy distillate to light distillate produced in a coal liquefaction process is continuously controlled by automatically and continuously controlling the ratio of heavy distillate to light distillate in a liquid solvent used to form the feed slurry to the coal liquefaction zone, and varying the weight ratio of heavy distillate to light distillate in the liquid solvent inversely with respect to the desired weight ratio of heavy distillate to light distillate in the distillate fuel oil product. The concentration of light distillate and heavy distillate in the liquid solvent is controlled by recycling predetermined amounts of light distillate and heavy distillate for admixture with feed coal to the process in accordance with the foregoing relationships. 3 figs.

Method for controlling boiling point distribution of coal liquefaction oil product

DOEpatents

Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles H.

1982-12-21

The relative ratio of heavy distillate to light distillate produced in a coal liquefaction process is continuously controlled by automatically and continuously controlling the ratio of heavy distillate to light distillate in a liquid solvent used to form the feed slurry to the coal liquefaction zone, and varying the weight ratio of heavy distillate to light distillate in the liquid solvent inversely with respect to the desired weight ratio of heavy distillate to light distillate in the distillate fuel oil product. The concentration of light distillate and heavy distillate in the liquid solvent is controlled by recycling predetermined amounts of light distillate and heavy distillate for admixture with feed coal to the process in accordance with the foregoing relationships.

Improving School Lighting for Video Display Units.

ERIC Educational Resources Information Center

Parker-Jenkins, Marie; Parker-Jenkins, William

1985-01-01

Provides information to identify and implement the key characteristics which contribute to an efficient and comfortable visual display unit (VDU) lighting installation. Areas addressed include VDU lighting requirements, glare, lighting controls, VDU environment, lighting retrofit, optical filters, and lighting recommendations. A checklist to…

Light-controlled motility in prokaryotes and the problem of directional light perception

PubMed Central

Wilde, Annegret

2017-01-01

Abstract The natural light environment is important to many prokaryotes. Most obviously, phototrophic prokaryotes need to acclimate their photosynthetic apparatus to the prevailing light conditions, and such acclimation is frequently complemented by motility to enable cells to relocate in search of more favorable illumination conditions. Non-phototrophic prokaryotes may also seek to avoid light at damaging intensities and wavelengths, and many prokaryotes with diverse lifestyles could potentially exploit light signals as a rich source of information about their surroundings and a cue for acclimation and behavior. Here we discuss our current understanding of the ways in which bacteria can perceive the intensity, wavelength and direction of illumination, and the signal transduction networks that link light perception to the control of motile behavior. We discuss the problems of light perception at the prokaryotic scale, and the challenge of directional light perception in small bacterial cells. We explain the peculiarities and the common features of light-controlled motility systems in prokaryotes as diverse as cyanobacteria, purple photosynthetic bacteria, chemoheterotrophic bacteria and haloarchaea. PMID:29077840

Light-controlled motility in prokaryotes and the problem of directional light perception.

PubMed

Wilde, Annegret; Mullineaux, Conrad W

2017-11-01

The natural light environment is important to many prokaryotes. Most obviously, phototrophic prokaryotes need to acclimate their photosynthetic apparatus to the prevailing light conditions, and such acclimation is frequently complemented by motility to enable cells to relocate in search of more favorable illumination conditions. Non-phototrophic prokaryotes may also seek to avoid light at damaging intensities and wavelengths, and many prokaryotes with diverse lifestyles could potentially exploit light signals as a rich source of information about their surroundings and a cue for acclimation and behavior. Here we discuss our current understanding of the ways in which bacteria can perceive the intensity, wavelength and direction of illumination, and the signal transduction networks that link light perception to the control of motile behavior. We discuss the problems of light perception at the prokaryotic scale, and the challenge of directional light perception in small bacterial cells. We explain the peculiarities and the common features of light-controlled motility systems in prokaryotes as diverse as cyanobacteria, purple photosynthetic bacteria, chemoheterotrophic bacteria and haloarchaea. © FEMS 2017.

Light exposure via a head-mounted device suppresses melatonin and improves vigilant attention without affecting cortisol and comfort.

PubMed

Schmidt, Christina; Xhrouet, Marine; Hamacher, Manon; Delloye, Eric; LeGoff, Caroline; Cavalier, Etienne; Collette, Fabienne; Vandewalle, Gilles

2018-06-26

We aimed at assessing whether a head-mounted light therapy device, enriched in blue wavelengths, suppresses melatonin secretion and improves vigilant attention in the late evening hours. We also assessed whether using such light device is associated with discomfort and physiological stress. Seventeen healthy young participants (eight females) participated in a counterbalanced within-subject design during which they were exposed for 2 hr before habitual sleep time to a blue-enriched light (1500 lx) or to a lower intensity red-light (150 lx) control condition, using a new-generation light emitting diode (LED) head-mounted device. Compared to the red light control condition, blue-enriched light significantly reduced melatonin secretion and reaction times during a psychomotor vigilance task while no significant differences were detected in discomfort and cortisol levels. These results suggest that, compared to a control condition, blue-enriched light, delivered by a new-generation head-mounted device, elicits typical non-visual responses to light without detectable discomfort and physiological stress. They suggest that such devices might constitute an effective alternative to standard light boxes. © 2018 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Lamp control using the principles of mathematical logic

NASA Astrophysics Data System (ADS)

Yudianto, E.; Firmansyah, F. F.; Akbar, P. S. B. S.; Nisyak, R.; Maudi, F. A.; Saputri, A. N.

2018-03-01

Along with the rapid development of technology, there are so many innovations on tools that can facilitate human’s work, one of which is a remote lamp controller. This light controller can provide convenience and comfort for people in turning on or off lights, especially they are traveling. The way remote light controller is used applies the principle of mathematical logic, particularly biimplication. The principle of mathematical logic (biimplication) on this light controller is applied to GSM module (gprs) and SMS.

Correlation of different spectral lights with biomass accumulation and production of antioxidant secondary metabolites in callus cultures of medicinally important Prunella vulgaris L.

PubMed

Fazal, Hina; Abbasi, Bilal Haider; Ahmad, Nisar; Ali, Syed Shujait; Akbar, Fazal; Kanwal, Farina

2016-06-01

Light is one of the key elicitors that directly fluctuates plant developmental processes and biosynthesis of secondary metabolites. In this study, the effects of various spectral lights on biomass accumulation and production of antioxidant secondary metabolites in callus cultures of Prunella vulgaris were investigated. Among different spectral lights, green light induced the maximum callogenic response (95%). Enhanced fresh biomass accumulation was observed in log phases on day-35, when callus cultures were exposed to yellow and violet lights. Yellow light induced maximum biomass accumulation (3.67g/100ml) from leaf explants as compared to control (1.27g/100ml). In contrast, violet lights enhanced biomass accumulation (3.49g/100ml) from petiole explant. Maximum total phenolics content (TPC; 23.9mg/g-DW) and total flavonoids content (TFC; 1.65mg/g-DW) were observed when cultures were grown under blue lights. In contrast, green and yellow lights enhanced total phenolics production (TPP; 112.52g/100ml) and total flavonoids production (TFP; 9.64g/100ml) as compared to control. The calli grown under green, red and blue lights enhanced DPPH-free radical scavenging activity (DFRSA; 91.3%, 93.1% and 93%) than control (56.44%) respectively. The DFRSA was correlated either with TPC and TFC or TPP and TFP. Furthermore, yellow lights enhanced superoxide dismutase (SOD), peroxidase (POD) and protease activities, however, the content of total protein (CTP) was higher in control cultures (186μg BSAE/mg FW) as compared to spectral lights. These results suggest that the exposure of callus cultures to various spectral lights have shown a key role in biomass accumulation and production of antioxidant secondary metabolites. Copyright © 2016 Elsevier B.V. All rights reserved.

Design and implementation of green intelligent lights based on the ZigBee

NASA Astrophysics Data System (ADS)

Gan, Yong; Jia, Chunli; Zou, Dongyao; Yang, Jiajia; Guo, Qianqian

2013-03-01

By analysis of the low degree of intelligence of the traditional lighting control methods, the paper uses the singlechip microcomputer for the control core, and uses a pyroelectric infrared technology to detect the existence of the human body, light sensors to sense the light intensity; the interface uses infrared sensor module, photosensitive sensor module, relay module to transmit the signal, which based on ZigBee wireless network. The main function of the design is to realize that the lighting can intelligently adjust the brightness according to the indoor light intensity when people in door, and it can turn off the light when people left. The circuit and program design of this system is flexible, and the system achieves the effect of intelligent energy saving control.

Research on starlight hardware-in-the-loop simulator

NASA Astrophysics Data System (ADS)

Zhang, Ying; Gao, Yang; Qu, Huiyang; Liu, Dongfang; Du, Huijie; Lei, Jie

2016-10-01

The starlight navigation is considered to be one of the most important methods for spacecraft navigation. Starlight simulation system is a high-precision system with large fields of view, designed to test the starlight navigation sensor performance on the ground. A complete hardware-in-the-loop simulation of the system has been built. The starlight simulator is made up of light source, light source controller, light filter, LCD, collimator and control computer. LCD is the key display component of the system, and is installed at the focal point of the collimator. For the LCD cannot emit light itself, so light source and light source power controller is specially designed for the brightness demanded by the LCD. Light filter is designed for the dark background which is also needed in the simulation.

Lighting Control Best Practice Guide: Schools.

ERIC Educational Resources Information Center

2002

This publication offers design, specification, and installation guidance for lighting control appropriate for K-12 educational facilities. It features applications that illustrate the best control practices for a variety of spaces, facilitating lighting control design and application. Each best practice meets the provisions of relevant energy…

Non-invasive three-dimension control of light between turbid layers using a surface quasi-point light source for precorrection.

PubMed

Qiao, Mu; Liu, Honglin; Pang, Guanghui; Han, Shensheng

2017-08-29

Manipulating light non-invasively through inhomogeneous media is an attractive goal in many disciplines. Wavefront shaping and optical phase conjugation can focus light to a point. Transmission matrix method can control light on multiple output modes simultaneously. Here we report a non-invasive approach which enables three-dimension (3D) light control between two turbid layers. A digital optical phase conjugation mirror measured and conjugated the diffused wavefront, which originated from a quasi-point source on the front turbid layer and passed through the back turbid layer. And then, because of memory effect, the phase-conjugated wavefront could be used as a carrier wave to transport a pre-calculated wavefront through the back turbid layer. The pre-calculated wavefront could project a desired 3D light field inside the sample, which, in our experiments, consisted of two 220-grid ground glass plates spaced by a 20 mm distance. The controllable range of light, according to the memory effect, was calculated to be 80 mrad in solid angle and 16 mm on z-axis. Due to the 3D light control ability, our approach may find applications in photodynamic therapy and optogenetics. Besides, our approach can also be combined with ghost imaging or compressed sensing to achieve 3D imaging between turbid layers.

Open-source products for a lighting experiment device.

PubMed

Gildea, Kevin M; Milburn, Nelda

2014-12-01

The capabilities of open-source software and microcontrollers were used to construct a device for controlled lighting experiments. The device was designed to ascertain whether individuals with certain color vision deficiencies were able to discriminate between the red and white lights in fielded systems on the basis of luminous intensity. The device provided the ability to control the timing and duration of light-emitting diode (LED) and incandescent light stimulus presentations, to present the experimental sequence and verbal instructions automatically, to adjust LED and incandescent luminous intensity, and to display LED and incandescent lights with various spectral emissions. The lighting device could easily be adapted for experiments involving flashing or timed presentations of colored lights, or the components could be expanded to study areas such as threshold light perception and visual alerting systems.

Effectiveness of traffic light vs. boom barrier controls at road-rail level crossings: a simulator study.

PubMed

Rudin-Brown, Christina M; Lenné, Michael G; Edquist, Jessica; Navarro, Jordan

2012-03-01

Although collisions at level crossings are relatively uncommon occurrences, the potential severity of their consequences make them a top priority among safety authorities. Twenty-five fully-licensed drivers aged between 20 and 50 years participated in a driving simulator study that compared the efficacy, and drivers' subjective perception, of two active level crossing traffic control devices: flashing lights with boom barriers and standard traffic lights. Because of its common usage in most states in Australia, a stop sign-controlled level crossing served as the passive referent. Although crossing violations were less likely at the level crossings controlled by active devices than at those controlled by stop signs, both kinds of active control were associated with a similar number of violations. Further, the majority (72%) of drivers reported preferring flashing lights to traffic lights. Collectively, results indicate that the installation of traffic lights at real-world level crossings would not be likely to offer safety benefits over and above those provided already by flashing lights with boom barriers. Furthermore, the high rate of violations at passively controlled crossings strongly supports the continued practice of upgrading level crossings with active traffic control devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

γ-glutamyl transpeptidase 1 specifically suppresses green-light avoidance via GABAA receptors in Drosophila.

PubMed

Liu, Jiangqu; Gong, Zhefeng; Liu, Li

2014-08-01

Drosophila larvae innately show light avoidance behavior. Compared with robust blue-light avoidance, larvae exhibit relatively weaker green-light responses. In our previous screening for genes involved in larval light avoidance, compared with control w(1118) larvae, larvae with γ-glutamyl transpeptidase 1 (Ggt-1) knockdown or Ggt-1 mutation were found to exhibit higher percentage of green-light avoidance which was mediated by Rhodopsin6 (Rh6) photoreceptors. However, their responses to blue light did not change significantly. By adjusting the expression level of Ggt-1 in different tissues, we found that Ggt-1 in malpighian tubules was both necessary and sufficient for green-light avoidance. Our results showed that glutamate levels were lower in Ggt-1 null mutants compared with controls. Feeding Ggt-1 null mutants glutamate can normalize green-light avoidance, indicating that high glutamate concentrations suppressed larval green-light avoidance. However, rather than directly, glutamate affected green-light avoidance indirectly through GABA, the level of which was also lower in Ggt-1 mutants compared with controls. Mutants in glutamate decarboxylase 1, which encodes GABA synthase, and knockdown lines of the GABAA receptor, both exhibit elevated levels of green-light avoidance. Thus, our results elucidate the neurobiological mechanisms mediating green-light avoidance, which was inhibited in wild-type larvae. © 2014 International Society for Neurochemistry.

Recreating the shading effects of ship wake induced turbidity to test acclimation responses in the seagrass Thalassia hemprichii

NASA Astrophysics Data System (ADS)

Browne, Nicola K.; Yaakub, Siti Maryam; Tay, Jason K. L.; Todd, Peter A.

2017-12-01

Elevated sediment delivery and resuspension in coastal waters from human activities such as shipping can have detrimental effects on seagrass health by limiting light penetration. Managing seagrasses requires knowledge of their light acclamatory abilities so guidelines for coastal activities (e.g. ship movements) that influence sediment dynamics can be created. Guidelines typically focus on ensuring that seagrasses are able to meet their minimal light requirements (MLR). MLRs can be achieved by different light regimes, but it remains unknown whether a chronically low yet stable light regime is less or more detrimental than a highly variable regime with periods of extreme low to no light. To test this, we compared the physiological and morphological responses of Thalassia hemprichii among three light regimes: an open control (30-40% ambient light), a shaded control with (11-15% ambient light), and a fluctuating shade (4-30% ambient light). The MLR for the T. hemprichii we studied was lower (4-10% ambient light) than previous reports (mean = 18%) illustrating enhanced light acclimation in Singapore's chronically turbid waters. Seagrass shoots in the shaded control, however, exhibited significantly more morphological stress symptoms, with reduced shoot growth and lower below ground biomass. These data suggest that for seagrass exposed to periods of acute light stress, energetic costs associated with photo-acclimation to more variable light regimes can be offset if the plant can meet its daily light requirements during periods of high light. Management of seagrass beds should incorporate regular light monitoring and move towards an adaptive feedback-based approach to ensure the long-term viability of these vulnerable ecosystems.

Direct imaging of slow, stored and stationary EIT polaritons

NASA Astrophysics Data System (ADS)

Campbell, Geoff T.; Cho, Young-Wook; Su, Jian; Everett, Jesse; Robins, Nicholas; Lam, Ping Koy; Buchler, Ben

2017-09-01

Stationary and slow light effects are of great interest for quantum information applications. Using laser-cooled Rb87 atoms, we performed side imaging of our atomic ensemble under slow and stationary light conditions, which allows direct comparison with numerical models. The polaritons were generated using electromagnetically induced transparency (EIT), with stationary light generated using counter-propagating control fields. By controlling the power ratio of the two control fields, we show fine control of the group velocity of the stationary light. We also compare the dynamics of stationary light using monochromatic and bichromatic control fields. Our results show negligible difference between the two situations, in contrast to previous work in EIT-based systems.

Effects of 530 nm green light on refractive status, melatonin, MT1 receptor, and melanopsin in the guinea pig.

PubMed

Wang, Fei; Zhou, Jiaqi; Lu, Yi; Chu, Renyuan

2011-02-01

To investigate (i) the effect of monochromatic light on inhibiting induction of light-induced melatonin and (ii) the roles of melanopsin and MT1 receptor in light-induced myopia in the guinea pig. Forty-eight guinea pigs were randomly distributed into three treatment groups: white-light (control), green-light (530 nm), and blue-light (480 nm) groups. Levels of pineal gland melatonin were measured twice daily--10:00 a.m. and 10:00 p.m.--10 days after initial light treatment. Thirty additional guinea pigs were also assigned to these groups and treated similarly. For these latter animals, refractive status, ocular length, and vitreous depth were measured before and after light treatment. Eight weeks after light treatment, retinal and sceral levels of melanopsin, melatonin receptor type (MT) 1, and mRNA protein were determined by Western blotting, real-time polymerase chain reaction (RT-PCR), and immunohistochemistry. The level of pineal gland melatonin in the green-light group was significantly higher than that in the blue-light group. Biometric measurements showed that guinea pigs in the green-light group had a somewhat myopic refractive status. Expressions of retinal melanopsin mRNA and protein were significantly higher in the blue-light group and lower in the green-light group when compared to controls. Conversely, expressions of MT1 receptor mRNA and protein in retina and sclera were significantly higher in the green-light group and lower in the blue-light group when compared to controls. Green light appears to suppress induction of melatonin production. In addition, 530 nm of green light is involved in the development of myopia. In the guinea pig, MT1 receptor and melanopsin appear to play roles in the development of myopia induced by 530 nm of light.

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

PubMed

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 < 0.05) than with the control eyewear. Sleep efficacy and sleep latency were significantly superior for wearers of the blue-light shield (P < 0.05 for both), and this group reported greater sleepiness during portable device use compared to those using the control eyewear. Participants rated the blue-light shield as providing acceptable visual quality.

Cyber Security for Lighting Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Fact sheet discusses cyber threats unique to lighting control systems in buildings and helps facility managers identify the types of lighting control systems that could introduce cybersecurity risks. Download the fact sheet.

Thumb-actuated two-axis controller

NASA Technical Reports Server (NTRS)

Hollow, R. H. (Inventor)

1986-01-01

A two axis joystick controller is described. It produces at least one output signal in relation to pivotal displacement of a member with respect to an intersection of the two axes. The member is pivotally movable on a support with respect to the two axes. The support has a centrally disposed aperture. A light source is mounted on the pivotally movable member above the aperture to direct light through the aperture. A light sensor is mounted below the aperture in the support at the intersection of the two axes to receive the light from the light source directed through the aperture. The light sensor produces at least one output signal related to a location on the sensor at which the light from the light source strikes the sensor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Case study describes how the Byron G. Rogers Federal Building replaced existing T12 and T8 luminaires with LED dedicated troffers with advanced controls. Together these measures cut lighting energy use by nearly 60% in the 18-story, 791,000-square-foot facility. The new lighting control system provides automated dimming of lights down to 0% output when daylight provides adequate light levels. The project earned GSA an award for exemplary performance from the Interior Lighting Campaign in 2016.

Spatial Light Modulator Would Serve As Electronic Iris

NASA Technical Reports Server (NTRS)

Gutow, David A.

1991-01-01

In proposed technique for controlling brightness of image formed by lens, spatial light modulator serves as segmented, electronically variable aperture. Offers several advantages: spatial light modulator controlled remotely and responds faster than motorized iris or other remotely controlled mechanical iris. Unlike iris, modulator also configured so as not to vary depth of field appreciably. Unlike lead lanthanum zirconate titanate crystal, spatial light modulator does not require high voltage.

Photoresponsive lipid-polymer hybrid nanoparticles for controlled doxorubicin release

NASA Astrophysics Data System (ADS)

Yao, Cuiping; Wu, Ming; Zhang, Cecheng; Lin, Xinyi; Wei, Zuwu; Zheng, Youshi; Zhang, Da; Zhang, Zhenxi; Liu, Xiaolong

2017-06-01

Currently, photoresponsive nanomaterials are particularly attractive due to their spatial and temporal controlled drug release abilities. In this work, we report a photoresponsive lipid-polymer hybrid nanoparticle for remote controlled delivery of anticancer drugs. This hybrid nanoparticle comprises three distinct functional components: (i) a poly(D,L-lactide-co-glycolide) (PLGA) core to encapsulate doxorubicin; (ii) a soybean lecithin monolayer at the interface of the core and shell to act as a molecular fence to prevent drug leakage; (iii) a photoresponsive polymeric shell with anti-biofouling properties to enhance nanoparticle stability, which could be detached from the nanoparticle to trigger the drug release via a decrease in the nanoparticle’s stability under light irradiation. In vitro results revealed that this core-shell nanoparticle had excellent light-controlled drug release behavior (76% release with light irradiation versus 10% release without light irradiation). The confocal microscopy and flow cytometry results also further demonstrated the light-controlled drug release behavior inside the cancer cells. Furthermore, a CCK8 assay demonstrated that light irradiation could significantly improve the efficiency of killing cancer cells. Meanwhile, whole-animal fluorescence imaging of a tumor-bearing mouse also confirmed that light irradiation could trigger drug release in vivo. Taken together, our data suggested that a hybrid nanoparticle could be a novel light controlled drug delivery system for cancer therapy.

Photo-actuation of liquids for light-driven microfluidics: state of the art and perspectives.

PubMed

Baigl, Damien

2012-10-07

Using light to control liquid motion is a new paradigm for the actuation of microfluidic systems. We review here the different principles and strategies to induce or control liquid motion using light, which includes the use of radiation pressure, optical tweezers, light-induced wettability gradients, the thermocapillary effect, photosensitive surfactants, the chromocapillary effect, optoelectrowetting, photocontrolled electroosmotic flows and optical dielectrophoresis. We analyze the performance of these approaches to control using light many kinds of microfluidic operations involving discrete pL- to μL-sized droplets (generation, driving, mixing, reaction, sorting) or fluid flows in microchannels (valve operation, injection, pumping, flow rate control). We show that a complete toolbox is now available to control microfluidic systems by light. We finally discuss the perspectives of digital optofluidics as well as microfluidics based on all optical fluidic chips and optically reconfigurable devices.

Monolithically integrated Si gate-controlled light-emitting device: science and properties

NASA Astrophysics Data System (ADS)

Xu, Kaikai

2018-02-01

The motivation of this study is to develop a p-n junction based light emitting device, in which the light emission is conventionally realized using reverse current driving, by voltage driving. By introducing an additional terminal of insulated gate for voltage driving, a novel three-terminal Si light emitting device is described where both the light intensity and spatial light pattern of the device are controlled by the gate voltage. The proposed light emitting device employs injection-enhanced Si in avalanche mode where electric field confinement occurs in the corner of a reverse-biased p+n junction. It is found that, depending on the bias conditions, the light intensity is either a linear or a quadratic function of the applied gate voltage or the reverse-bias. Since the light emission is based on the avalanching mode, the Si light emitting device offers the potential for very large scale integration-compatible light emitters for inter- or intra-chip signal transmission and contactless functional testing of wafers.

75 FR 7426 - Tier 2 Light-Duty Vehicle and Light-Duty Truck Emission Standards and Gasoline Sulfur Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-19

... 2060-AI23; 2060-AQ12 Tier 2 Light-Duty Vehicle and Light-Duty Truck Emission Standards and Gasoline... February 10, 2000 (65 FR 6698), EPA published emission standards for light-duty vehicles and light-duty... new passenger cars and light trucks, including pickup trucks, vans, minivans, and sport-utility...

Flash protection controller

DOEpatents

Galbraith, L.K.

1979-12-07

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

Flash protection controller

DOEpatents

Galbraith, Lee K.

1981-01-01

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

International Lighting in Controlled Environments Workshop

NASA Technical Reports Server (NTRS)

Tibbits, Ted W. (Editor)

1994-01-01

Lighting is a central and critical aspect of control in environmental research for plant research and is gaining recognition as a significant factor to control carefully for animal and human research. Thus this workshop was convened to reevaluate the technology that is available today and to work toward developing guidelines for the most effective use of lighting in controlled environments with emphasis on lighting for plants but also to initiate interest in the development of improved guidelines for human and animal research.

Effect of a photoperiodic green light programme during incubation on embryo development and hatch process.

PubMed

Tong, Q; McGonnell, I M; Demmers, T G M; Roulston, N; Bergoug, H; Romanini, C E; Verhelst, R; Guinebretière, M; Eterradossi, N; Berckmans, D; Exadaktylos, V

2018-04-01

This study was conducted to evaluate the effect of a 12-h light, 12-h dark (12L : 12D) photoperiod of green light during day 1 to day 18 of incubation time, on embryo growth, hormone concentration and the hatch process. In the test group, monochromatic light was provided by a total of 204 green light-emitting diodes (522 nm) mounted in a frame which was placed above the top tray of eggs to give even spread of illumination. No light-dark cycle was used in the control group. Four batches of eggs (n=300/group per batch) from fertile Ross 308 broiler breeders were used in this experiment. The beak length and crown-rump length of embryos incubated under green light were significantly longer than that of control embryos at day 10 and day 12, respectively (P<0.01). Furthermore, green light-exposed embryos had a longer third toe length compared with control embryos at day 10, day 14 and day 17 (P=0.02). At group level (n=4 batches), light stimulation had no effect on chick weight and quality at take-off, the initiation of hatch and hatch window. However, the individual hatching time of the light exposure focal chicks (n=33) was 3.4 h earlier (P=0.49) than the control focal chicks (n=36) probably due to the change in melatonin rhythm of the light group. The results of this study indicate that green light accelerates embryo development and alters hatch-related hormones (thyroid and corticosterone), which may result in earlier hatching.

14 CFR 139.311 - Marking, signs, and lighting.

Code of Federal Regulations, 2011 CFR

2011-01-01

... prevent interference with air traffic control and aircraft operations. (f) Standards. FAA Advisory... following taxiway lighting systems: (i) Centerline lights. (ii) Centerline reflectors. (iii) Edge lights...

Redwood seedling responses to light patterns and intensities

Treesearch

Ronald W. Boldenow; Joe R. McBride

2017-01-01

Coast redwood (Sequoia sempervirens (D. Don) Endl.) seedlings were grown from seed in controlled environments with 16 hour photoperiods using three light patterns that mimicked full shade (constant light level), intermittent high light such as long duration sun flecks (low light with 15 minutes of intense light every 2 hours), and large...

40 CFR 86.1840-01 - Special test procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks... those set forth in this part, for any light-duty vehicle, light-duty truck, or complete heavy-duty... special test procedures but the Administrator determines that a light-duty vehicle, light-duty truck, or...

Getting back to nature: a reality check for experiments in controlled environments.

PubMed

Annunziata, Maria Grazia; Apelt, Federico; Carillo, Petronia; Krause, Ursula; Feil, Regina; Mengin, Virginie; Lauxmann, Martin A; Köhl, Karin; Nikoloski, Zoran; Stitt, Mark; Lunn, John E; Raines, Christine

2017-07-20

Irradiance from sunlight changes in a sinusoidal manner during the day, with irregular fluctuations due to clouds, and light-dark shifts at dawn and dusk are gradual. Experiments in controlled environments typically expose plants to constant irradiance during the day and abrupt light-dark transitions. To compare the effects on metabolism of sunlight versus artificial light regimes, Arabidopsis thaliana plants were grown in a naturally illuminated greenhouse around the vernal equinox, and in controlled environment chambers with a 12-h photoperiod and either constant or sinusoidal light profiles, using either white fluorescent tubes or light-emitting diodes (LEDs) tuned to a sunlight-like spectrum as the light source. Rosettes were sampled throughout a 24-h diurnal cycle for metabolite analysis. The diurnal metabolite profiles revealed that carbon and nitrogen metabolism differed significantly between sunlight and artificial light conditions. The variability of sunlight within and between days could be a factor underlying these differences. Pairwise comparisons of the artificial light sources (fluorescent versus LED) or the light profiles (constant versus sinusoidal) showed much smaller differences. The data indicate that energy-efficient LED lighting is an acceptable alternative to fluorescent lights, but results obtained from plants grown with either type of artificial lighting might not be representative of natural conditions. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Enhancing Three-dimensional Movement Control System for Assemblies of Machine-Building Facilities

NASA Astrophysics Data System (ADS)

Kuzyakov, O. N.; Andreeva, M. A.

2018-01-01

Aspects of enhancing three-dimensional movement control system are given in the paper. Such system is to be used while controlling assemblies of machine-building facilities, which is a relevant issue. The base of the system known is three-dimensional movement control device with optical principle of action. The device consists of multi point light emitter and light receiver matrix. The processing of signals is enhanced to increase accuracy of measurements by switching from discrete to analog signals. Light receiver matrix is divided into four areas, and the output value of each light emitter in each matrix area is proportional to its luminance level. Thus, determing output electric signal value of each light emitter in corresponding area leads to determing position of multipoint light emitter and position of object tracked. This is done by using Case-based reasoning method, the precedent in which is described as integral signal value of each matrix area, coordinates of light receivers, which luminance level is high, and decision to be made in this situation.

Smart lighting using a liquid crystal modulator

NASA Astrophysics Data System (ADS)

Baril, Alexandre; Thibault, Simon; Galstian, Tigran

2017-08-01

Now that LEDs have massively invaded the illumination market, a clear trend has emerged for more efficient and targeted lighting. The project described here is at the leading edge of the trend and aims at developing an evaluation board to test smart lighting applications. This is made possible thanks to a new liquid crystal light modulator recently developed for broadening LED light beams. The modulator is controlled by electrical signals and is characterized by a linear working zone. This feature allows the implementation of a closed loop control with a sensor feedback. This project shows that the use of computer vision is a promising opportunity for cheap closed loop control. The developed evaluation board integrates the liquid crystal modulator, a webcam, a LED light source and all the required electronics to implement a closed loop control with a computer vision algorithm.

Apparatus and process for active pulse intensity control of laser beam

DOEpatents

Wilcox, Russell B.

1992-01-01

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Feasibility of touch-less control of operating room lights.

PubMed

Hartmann, Florian; Schlaefer, Alexander

2013-03-01

Today's highly technical operating rooms lead to fairly complex surgical workflows where the surgeon has to interact with a number of devices, including the operating room light. Hence, ideally, the surgeon could direct the light without major disruption of his work. We studied whether a gesture tracking-based control of an automated operating room light is feasible. So far, there has been little research on control approaches for operating lights. We have implemented an exemplary setup to mimic an automated light controlled by a gesture tracking system. The setup includes a articulated arm to position the light source and an off-the-shelf RGBD camera to detect the user interaction. We assessed the tracking performance using a robot-mounted hand phantom and ran a number of tests with 18 volunteers to evaluate the potential of touch-less light control. All test persons were comfortable with using the gesture-based system and quickly learned how to move a light spot on flat surface. The hand tracking error is direction-dependent and in the range of several centimeters, with a standard deviation of less than 1 mm and up to 3.5 mm orthogonal and parallel to the finger orientation, respectively. However, the subjects had no problems following even more complex paths with a width of less than 10 cm. The average speed was 0.15 m/s, and even initially slow subjects improved over time. Gestures to initiate control can be performed in approximately 2 s. Two-thirds of the subjects considered gesture control to be simple, and a majority considered it to be rather efficient. Implementation of an automated operating room light and touch-less control using an RGBD camera for gesture tracking is feasible. The remaining tracking error does not affect smooth control, and the use of the system is intuitive even for inexperienced users.

Artwork visualization using a solid-state lighting engine with controlled photochemical safety.

PubMed

Tuzikas, Arūnas; Žukauskas, Artūras; Vaicekauksas, Rimantas; Petrulis, Andrius; Vitta, Pranciškus; Shur, Michael

2014-07-14

A concept of a solid-state lighting engine for artwork-specific illumination with controlled photochemical safety is introduced. The engine is based on a tetrachromatic cluster of colored light-emitting diodes wirelessly controlled via an external smart device. By using an instantaneous dimming functionality, the driving software allows for maintaining the damage irradiance relevant to a particular type of photosensitive artwork material at a constant value, while varying the chromaticity and color rendition properties of the generated light. The effect of the constant damage irradiance on the visual impression from artworks is demonstrated for the lighting engine operating in three modes, such as selecting color temperature, tuning color saturating ability, and shifting chromaticity outside white light locus, respectively.

LightLeaves: computer controlled kinetic reflection hologram installation and a brief discussion of earlier work

NASA Astrophysics Data System (ADS)

Connors Chen, Betsy

2013-02-01

LightLeaves is an installation combining leaf shaped, white light reflection holograms of landscape images with a special kinetic lighting device that houses a lamp and moving leaf shaped masks. The masks are controlled by an Arduino microcontroller and servomotors that position the masks in front of the illumination source of the holograms. The work is the most recent in a long series of landscapes that combine multi-hologram installations with computer controlled devices that play with the motion of the holograms, the light, sound or other elements in the work. LightLeaves was first exhibited at the Peabody Essex Museum in Salem, Massachusetts in a show titled "Eye Spy: Playing with Perception".

Daily Profiles of Light Exposure and Evening Use of Light-emitting Devices in Young Adults Complaining of a Delayed Sleep Schedule.

PubMed

Van der Maren, Solenne; Moderie, Christophe; Duclos, Catherine; Paquet, Jean; Daneault, Véronique; Dumont, Marie

2018-04-01

A number of factors can contribute to a delayed sleep schedule. An important factor could be a daily profile of light exposure favoring a later circadian phase. This study aimed to compare light exposure between 14 young adults complaining of a delayed sleep schedule and 14 matched controls and to identify possible associations between habitual light exposure and circadian phase. Exposure to white and blue light was recorded with ambulatory monitors for 7 consecutive days. Participants also noted their daily use of light-emitting devices before bedtime. Endogenous circadian phase was estimated with the dim light melatonin onset (DLMO) in the laboratory. The amplitude of the light-dark cycle to which the subjects were exposed was smaller in delayed than in control subjects, and smaller amplitude was associated with a later DLMO. Smaller amplitude was due to both decreased exposure in the daytime and increased exposure at night. Total exposure to blue light, but not to white light, was lower in delayed subjects, possibly due to lower exposure to blue-rich outdoor light. Lower daily exposure to blue light was associated with a later DLMO. Timing of relative increases and decreases of light exposure in relation to endogenous circadian phase was also compared between the 2 groups. In delayed subjects, there was a relatively higher exposure to white and blue light 2 h after DLMO, a circadian time with maximal phase-delaying effect. Delayed participants also had higher exposure to light 8 to 10 h after DLMO, which occurred mostly during their sleep episode but may have some phase-advancing effects. Self-reported use of light-emitting devices before bedtime was higher in delayed than in control subjects and was associated with a later DLMO. This study suggests that individuals complaining of a delayed sleep schedule engage in light-related behaviors favoring a later circadian phase and a later bedtime.

Efficient semiconductor light-emitting device and method

DOEpatents

Choquette, Kent D.; Lear, Kevin L.; Schneider, Jr., Richard P.

1996-01-01

A semiconductor light-emitting device and method. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL).

Efficient semiconductor light-emitting device and method

DOEpatents

Choquette, K.D.; Lear, K.L.; Schneider, R.P. Jr.

1996-02-20

A semiconductor light-emitting device and method are disclosed. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL). 12 figs.

Optical Fiber Illumination System for visual flight simulation

NASA Technical Reports Server (NTRS)

Hollow, R. H.

1981-01-01

An electronically controlled lighting system simulating runway, aircraft carrier, and landing aid lights for flight simulations is described. The various colored lights that would be visible to a pilot by day, at dusk, or at night are duplicated at the distances the lights would normally become visible. Plastic optical fiber illuminators using tungsten halogen lights are distributed behind the model. The tips of the fibers of illuminators simulating runway lights are bevelled in order that they may be seen from long distances and at low angles. Fibers representing taxiway lights are pointed and polished for omni-directional visibility. The electronic intensity controls, which can be operated either manually or remotely, regulate the intensity of the lights to simulate changes in distance. A dichronic mirror, infrared filter system is used to maintain color integrity.

Tools for controlling protein interactions with light

PubMed Central

Tucker, Chandra L.; Vrana, Justin D.; Kennedy, Matthew J.

2014-01-01

Genetically-encoded actuators that allow control of protein-protein interactions with light, termed ‘optical dimerizers’, are emerging as new tools for experimental biology. In recent years, numerous new and versatile dimerizer systems have been developed. Here we discuss the design of optical dimerizer experiments, including choice of a dimerizer system, photoexcitation sources, and coordinate use of imaging reporters. We provide detailed protocols for experiments using two dimerization systems we previously developed, CRY2/CIB and UVR8/UVR8, for use controlling transcription, protein localization, and protein secretion with light. Additionally, we provide instructions and software for constructing a pulse-controlled LED light device for use in experiments requiring extended light treatments. PMID:25181301

Control over high peak-power laser light and laser-driven X-rays

NASA Astrophysics Data System (ADS)

Zhao, Baozhen; Banerjee, Sudeep; Yan, Wenchao; Zhang, Ping; Zhang, Jun; Golovin, Grigory; Liu, Cheng; Fruhling, Colton; Haden, Daniel; Chen, Shouyuan; Umstadter, Donald

2018-04-01

An optical system was demonstrated that enables continuous control over the peak power level of ultrashort duration laser light. The optical characteristics of amplified and compressed femtosecond-duration light from a chirped-pulse amplification laser are shown to remain invariant and maintain high-fidelity using this system. When the peak power was varied by an order-of-magnitude, up to its maximum attainable value, the phase, spectral bandwidth, polarization state, and focusability of the light remained constant. This capability led to precise control of the focused laser intensity and enabled a correspondingly high level of control over the power of an all-laser-driven Thomson X-ray light source.

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

PubMed

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.

Blue light-mediated transcriptional activation and repression of gene expression in bacteria

PubMed Central

Jayaraman, Premkumar; Devarajan, Kavya; Chua, Tze Kwang; Zhang, Hanzhong; Gunawan, Erry; Poh, Chueh Loo

2016-01-01

Light-regulated modules offer unprecedented new ways to control cellular behavior in precise spatial and temporal resolution. The availability of such tools may dramatically accelerate the progression of synthetic biology applications. Nonetheless, current optogenetic toolbox of prokaryotes has potential issues such as lack of rapid and switchable control, less portable, low dynamic expression and limited parts. To address these shortcomings, we have engineered a novel bidirectional promoter system for Escherichia coli that can be induced or repressed rapidly and reversibly using the blue light dependent DNA-binding protein EL222. We demonstrated that by modulating the dosage of light pulses or intensity we could control the level of gene expression precisely. We show that both light-inducible and repressible system can function in parallel with high spatial precision in a single cell and can be switched stably between ON- and OFF-states by repetitive pulses of blue light. In addition, the light-inducible and repressible expression kinetics were quantitatively analysed using a mathematical model. We further apply the system, for the first time, to optogenetically synchronize two receiver cells performing different logic behaviors over time using blue light as a molecular clock signal. Overall, our modular approach layers a transformative platform for next-generation light-controllable synthetic biology systems in prokaryotes. PMID:27353329

Effect of light intensity on flight control and temporal properties of photoreceptors in bumblebees.

PubMed

Reber, Therese; Vähäkainu, Antti; Baird, Emily; Weckström, Matti; Warrant, Eric; Dacke, Marie

2015-05-01

To control flight, insects rely on the pattern of visual motion generated on the retina as they move through the environment. When light levels fall, vision becomes less reliable and flight control thus becomes more challenging. Here, we investigated the effect of light intensity on flight control by filming the trajectories of free-flying bumblebees (Bombus terrestris, Linnaeus 1758) in an experimental tunnel at different light levels. As light levels fell, flight speed decreased and the flight trajectories became more tortuous but the bees were still remarkably good at centring their flight about the tunnel's midline. To investigate whether this robust flight performance can be explained by visual adaptations in the bumblebee retina, we also examined the response speed of the green-sensitive photoreceptors at the same light intensities. We found that the response speed of the photoreceptors significantly decreased as light levels fell. This indicates that bumblebees have both behavioural (reduction in flight speed) and retinal (reduction in response speed of the photoreceptors) adaptations to allow them to fly in dim light. However, the more tortuous flight paths recorded in dim light suggest that these adaptations do not support flight with the same precision during the twilight hours of the day. © 2015. Published by The Company of Biologists Ltd.

Visible light reduces C. elegans longevity.

PubMed

De Magalhaes Filho, C Daniel; Henriquez, Brian; Seah, Nicole E; Evans, Ronald M; Lapierre, Louis R; Dillin, Andrew

2018-03-02

The transparent nematode Caenorhabditis elegans can sense UV and blue-violet light to alter behavior. Because high-dose UV and blue-violet light are not a common feature outside of the laboratory setting, we asked what role, if any, could low-intensity visible light play in C. elegans physiology and longevity. Here, we show that C. elegans lifespan is inversely correlated to the time worms were exposed to visible light. While circadian control, lite-1 and tax-2 do not contribute to the lifespan reduction, we demonstrate that visible light creates photooxidative stress along with a general unfolded-protein response that decreases the lifespan. Finally, we find that long-lived mutants are more resistant to light stress, as well as wild-type worms supplemented pharmacologically with antioxidants. This study reveals that transparent nematodes are sensitive to visible light radiation and highlights the need to standardize methods for controlling the unrecognized biased effect of light during lifespan studies in laboratory conditions.

Effects of bright and blue light on acoustic reaction time and maximum handgrip strength in male athletes: a randomized controlled trial.

PubMed

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

2017-08-01

To assess which type of evening light exposure has the greatest effect on reaction time and maximum handgrip strength. These were pre-specified secondary outcomes in a trial which primarily investigated the influence of light on cycling performance. Seventy-four male athletes were allocated at random to either bright light (BRIGHT), monochromatic blue light (BLUE), or a control condition (CONTROL). Light exposure lasted for 60 min and started 17 h after the individual midpoint of sleep. Reaction time, handgrip strength, and melatonin levels were measured before and after the light exposure. We used analysis of covariance to compare the groups with respect to the investigated outcomes. Two participants had to be excluded retrospectively. The remaining 72 participants had a median age of 23 years. The adjusted difference in reaction time was -1 ms [95% confidence interval (CI) -8, 6] for participants in BRIGHT and 2 ms (95% CI -5, 9) for participants in BLUE, both relative to participants in CONTROL. The adjusted difference in handgrip strength was 0.9 kg (95% CI -1.5, 3.3) for participants in BRIGHT and -0.3 kg (95% CI -2.7, 2.0) for participants in BLUE, both relative to participants in CONTROL. After the light exposure, 17% of participants in BRIGHT, 22% in BLUE, and 29% in CONTROL showed melatonin concentrations of 2 pg/ml or higher. The results suggest that bright light might reduce melatonin levels but neither bright nor blue light exposure in the evening seem to improve reaction time or handgrip strength in athletes.

Developing Flexible Networked Lighting Control Systems

Science.gov Websites

, Bluetooth, ZigBee and others are increasingly used for building control purposes. Low-cost computation : Bundling digital intelligence at the sensors and lights adds virtually no incremental cost. Coupled with cost. Research Goals and Objectives This project "Developing Flexible, Networked Lighting Control

HORIZONTAL HYBRID SOLAR LIGHT PIPE: AN INTEGRATED SYSTEM OF DAYLIGHT AND ELECTRIC LIGHT

EPA Science Inventory

This project will test the feasibility of an advanced energy efficient perimeter lighting system that integrates daylighting, electric lighting, and lighting controls to reduce electricity consumption. The system is designed to provide adequate illuminance levels in deep-floor...

Management of fluorescent lamps in controlled environment chambers

NASA Technical Reports Server (NTRS)

Romer, Mark

1994-01-01

Management of fluorescent lights is recommended to (1) maintain uniformity of light intensity over time and (2) permit reproducibility of lighting conditions during experimental replications. At the McGill Phytotron, the lighting intensity can be controlled to desired level because any individual pair of the 40 lamps in each chamber can be set to be 'on' at any particular time. A lamp canopy service history is maintained for each experiment permitting accurate replication of lighting conditions for subsequent replicate trials.

Design considerations for a backlight with switchable viewing angles

NASA Astrophysics Data System (ADS)

Fujieda, Ichiro; Takagi, Yoshihiko; Rahadian, Fanny

2006-08-01

Small-sized liquid crystal displays are widely used for mobile applications such as cell phones. Electronic control of a viewing angle range is desired in order to maintain privacy for viewing in public as well as to provide wide viewing angles for solitary viewing. Conventionally, a polymer-dispersed liquid crystal (PDLC) panel is inserted between a backlight and a liquid crystal panel. The PDLC layer either transmits or scatters the light from the backlight, thus providing an electronic control of viewing angles. However, such a display system is obviously thick and expensive. Here, we propose to place an electronically-controlled, light-deflecting device between an LED and a light-guide of a backlight. For example, a liquid crystal lens is investigated for other applications and its focal length is controlled electronically. A liquid crystal phase grating either transmits or diffracts an incoming light depending on whether or not a periodic phase distribution is formed inside its liquid crystal layer. A bias applied to such a device will control the angular distribution of the light propagating inside a light-guide. Output couplers built in the light-guide extract the propagating light to outside. They can be V-shaped grooves, pyramids, or any other structures that can refract, reflect or diffract light. When any of such interactions occur, the output couplers translate the changes in the propagation angles into the angular distribution of the output light. Hence the viewing-angle characteristic can be switched. The designs of the output couplers and the LC devices are important for such a backlight system.

Light-switchable systems for remotely controlled drug delivery.

PubMed

Shim, Gayong; Ko, Seungbeom; Kim, Dongyoon; Le, Quoc-Viet; Park, Gyu Thae; Lee, Jaiwoo; Kwon, Taekhyun; Choi, Han-Gon; Kim, Young Bong; Oh, Yu-Kyoung

2017-12-10

Light-switchable systems have recently received attention as a new mode of remotely controlled drug delivery. In the past, a multitude of nanomedicine studies have sought to enhance the specificity of drug delivery to target sites by focusing on receptors overexpressed on malignant cells or environmental features of diseases sites. Despite these immense efforts, however, there are few clinically available nanomedicines. We need a paradigm shift in drug delivery. One strategy that may overcome the limitations of pathophysiology-based drug delivery is the use of remotely controlled delivery technology. Unlike pathophysiology-based active drug targeting strategies, light-switchable systems are not affected by the heterogeneity of cells, tissue types, and/or microenvironments. Instead, they are triggered by remote light (i.e., near-infrared) stimuli, which are absorbed by photoresponsive molecules or three-dimensional nanostructures. The sequential conversion of light to heat or reactive oxygen species can activate drug release and allow it to be spatio-temporally controlled. Light-switchable systems have been used to activate endosomal drug escape, modulate the release of chemical and biological drugs, and alter nanoparticle structures to control the release rates of drugs. This review will address the limitations of pathophysiology-based drug delivery systems, the current status of light-based remote-switch systems, and future directions in the application of light-switchable systems for remotely controlled drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

Apparatus and Method for Focusing a Light Beam in a Three-Dimensional Recording Medium by a Dynamic Holographic Device

NASA Technical Reports Server (NTRS)

Juday, Richard D. (Inventor)

1998-01-01

An apparatus is disclosed for reading and/or writing information or to from an optical recording medium having a plurality of information storage layers. The apparatus includes a dynamic holographic optical element configured to focus light on the optical recording medium. a control circuit arranged to supply a drive signal to the holographic optical element, and a storage device in communication with the control circuit and storing at least a first drive signal and a second drive signal. The holographic optical element focusses light on a first one of the plurality of information storage layers when driven by the first drive signal on a second one of the plurality of information storage layers when driven by the second drive signal. An optical switch is also disclosed for connecting at least one light source in a source array to at least one light receiver in a receiver array. The switch includes a dynamic holographic optical element configured to receive light from the source array and to transmit light to the receiver array, a control circuit arranged to supply a drive signal to the holographic optical element, and a storage device in communication with the control circuit and storing at least a first drive signal and a second drive signal. The holographic optical element connects a first light source in the source array to a first light receiver in the receiver array when driven by the first drive signal and the holographic optical element connects the first light source with the first light receiver and a second light receiver when driven by the second drive signal.

A novel phototropic response to red light is revealed in microgravity.

PubMed

Millar, Katherine D L; Kumar, Prem; Correll, Melanie J; Mullen, Jack L; Hangarter, Roger P; Edelmann, Richard E; Kiss, John Z

2010-05-01

The aim of this study was to investigate phototropism in plants grown in microgravity conditions without the complications of a 1-g environment. Experiments performed on the International Space Station (ISS) were used to explore the mechanisms of both blue-light- and red-light-induced phototropism in plants. This project utilized the European Modular Cultivation System (EMCS), which has environmental controls for plant growth as well as centrifuges for gravity treatments used as a 1-g control. Images captured from video tapes were used to analyze the growth, development, and curvature of Arabidopsis thaliana plants that developed from seed in space. A novel positive phototropic response to red light was observed in hypocotyls of seedlings that developed in microgravity. This response was not apparent in seedlings grown on Earth or in the 1-g control during the space flight. In addition, blue-light-based phototropism had a greater response in microgravity compared with the 1-g control. Although flowering plants are generally thought to lack red light phototropism, our data suggest that at least some flowering plants may have retained a red light sensory system for phototropism. Thus, this discovery may have important implications for understanding the evolution of light sensory systems in plants.

Controllable light beam shaper in LED lamp

NASA Astrophysics Data System (ADS)

Nessemon, K. D.; Popov, I. V.; Belyaev, V. V.; Belyaev, A. A.; Velichko, V. K.

2018-03-01

A design of an LED lamp with controllable shape and intensity of the light beam formed is described. The effect is achieved by dividing the light irradiating area for four section and their special fixation and fastening.

Adaptive lighting controllers using smart sensors

NASA Astrophysics Data System (ADS)

Papantoniou, Sotiris; Kolokotsa, Denia; Kalaitzakis, Kostas; Cesarini, Davide Nardi; Cubi, Eduard; Cristalli, Cristina

2016-07-01

The aim of this paper is to present an advanced controller for artificial lights evaluated in several rooms in two European Hospitals located in Chania, Greece and Ancona, Italy. Fuzzy techniques have been used for the architecture of the controller. The energy efficiency of the controllers has been calculated by running the controller coupled with validated models of the RADIANCE back-wards ray tracing software. The input of the controller is the difference between the current illuminance value and the desired one, while the output is the change of the light level that should be applied in the artificial lights. Simulation results indicate significant energy saving potentials. Energy saving potential is calculated from the comparison of the current use of the artificial lights by the users and the proposed one. All simulation work has been conducted using Matlab and RADIANCE environment.

49 CFR 533.6 - Measurement and calculation procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LIGHT TRUCK FUEL ECONOMY STANDARDS § 533.6... manufacturer shall be deemed— (1) To include all light trucks in that class manufactured by persons who control, are controlled by, or are under common control with, such manufacturer; and (2) To exclude all light...

49 CFR 533.6 - Measurement and calculation procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LIGHT TRUCK FUEL ECONOMY STANDARDS § 533.6... manufacturer shall be deemed— (1) To include all light trucks in that class manufactured by persons who control, are controlled by, or are under common control with, such manufacturer; and (2) To exclude all light...

Bimorphic polymeric photomechanical actuator

NASA Technical Reports Server (NTRS)

Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

2006-01-01

A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

Efficient in vitro photodynamic inactivation of Candida albicans by repetitive light doses

NASA Astrophysics Data System (ADS)

Torres-Hurtado, S. A.; Ramírez Ramírez, J.; Ramos-García, R.; Ramírez-San-Juan, J. C.; Spezzia-Mazzocco, T.

2018-02-01

The aim of this study was to compare the effectiveness of Rose Bengal (RB) and Methylene Blue (MB) as photosensitizers (PS) in Photodynamic Inactivation (PDI) on planktonic cultures of Candida albicans, a well-known opportunistic pathogen. RB and MB at concentrations ranging from 0.5 to 60 μM and fluences of 10, 30, 45 and 60 J/cm2 were tested. The light sources consist of an array of 12 led diodes with 30 mW of optical power each; 490-540 nm (green light) to activate RB and 600 -650 nm (red light) to activate MB. We first optimize the in vitro PDI technique using a single light dose and the optimum PS concentration. The novelty of our approach consist in reducing further the PS concentration than the optimum obtained with a single light exposure and using smaller light fluence doses by using repetitive light exposures (two to three times). MB and RB were tested for repetitive exposures at concentrations ranging from 0.1 to 10 μM, with fluences of 3 to 20 J/cm2, doses well below than those reported previously. All experiments were done in triplicate with the corresponding controls; cells without treatment, light control and dark toxicity control. RB-PDI and MB-PDI significantly reduced the number of CFU/mL when compared to the control groups. The results showed that RB was more effective than MB for C. albicans inactivation. Thus, we show that is possible to reduce significantly the amount of PS and light fluence requirements using repetitive light doses of PDI in vitro.

Exposure to Visible Light Emitted from Smartphones and Tablets Increases the Proliferation of Staphylococcus aureus: Can this be Linked to Acne?

PubMed Central

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

40 CFR 86.1771-99 - Fuel specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Provisions for the Voluntary National Low Emission Vehicle Program for Light-Duty Vehicles and Light-Duty... following exceptions and additions. (1) For light-duty vehicles and light light-duty trucks, gasoline having...

40 CFR 86.1771-99 - Fuel specifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Provisions for the Voluntary National Low Emission Vehicle Program for Light-Duty Vehicles and Light-Duty... following exceptions and additions. (1) For light-duty vehicles and light light-duty trucks, gasoline having...

40 CFR 86.1848-01 - Certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and... the implementation schedule shall not be covered by the certificate. (4) For incomplete light-duty... new light-duty vehicles, light-duty trucks, and complete heavy-duty vehicles must obtain a certificate...

14 CFR 23.1381 - Instrument lights.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Instrument lights. 23.1381 Section 23.1381... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1381 Instrument lights. The instrument lights must— (a) Make each instrument and control easily readable and discernible...

14 CFR 23.1381 - Instrument lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Instrument lights. 23.1381 Section 23.1381... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1381 Instrument lights. The instrument lights must— (a) Make each instrument and control easily readable and discernible...

14 CFR 23.1381 - Instrument lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Instrument lights. 23.1381 Section 23.1381... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1381 Instrument lights. The instrument lights must— (a) Make each instrument and control easily readable and discernible...

14 CFR 23.1381 - Instrument lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Instrument lights. 23.1381 Section 23.1381... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1381 Instrument lights. The instrument lights must— (a) Make each instrument and control easily readable and discernible...

14 CFR 23.1381 - Instrument lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Instrument lights. 23.1381 Section 23.1381... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Lights § 23.1381 Instrument lights. The instrument lights must— (a) Make each instrument and control easily readable and discernible...

Multichannel optical sensing device

DOEpatents

Selkowitz, S.E.

1985-08-16

A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

Multichannel optical sensing device

DOEpatents

Selkowitz, Stephen E.

1990-01-01

A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

Imaging arrangement and microscope

DOEpatents

Pertsinidis, Alexandros; Chu, Steven

2015-12-15

An embodiment of the present invention is an imaging arrangement that includes imaging optics, a fiducial light source, and a control system. In operation, the imaging optics separate light into first and second tight by wavelength and project the first and second light onto first and second areas within first and second detector regions, respectively. The imaging optics separate fiducial light from the fiducial light source into first and second fiducial light and project the first and second fiducial light onto third and fourth areas within the first and second detector regions, respectively. The control system adjusts alignment of the imaging optics so that the first and second fiducial light projected onto the first and second detector regions maintain relatively constant positions within the first and second detector regions, respectively. Another embodiment of the present invention is a microscope that includes the imaging arrangement.

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks Certifying to the Provisions of Part 86... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

40 CFR Appendix Xviii to Part 86 - Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Statistical Outlier Identification Procedure for Light-Duty Vehicles and Light Light-Duty Trucks Certifying to the Provisions of Part 86... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

The treatment of early-morning awakening insomnia with 2 evenings of bright light.

PubMed

Lack, Leon; Wright, Helen; Kemp, Kristyn; Gibbon, Samantha

2005-05-01

To assess the effectiveness of brief bright-light therapy for the treatment of early-morning awakening insomnia. Twenty-four healthy adults with early-morning awakening insomnia were assigned to either the bright-light condition (2,500-lux white light) or the control (dim red light) condition. The circadian phase of rectal temperature and urinary melatonin rhythms were assessed with 26-hour constant routines before and after 2 evenings of light therapy. Sleep and daytime functioning were monitored using sleep diaries, activity monitors, and mood scales before light therapy and for 4 weeks during the follow-up period. While there were no significant circadian phase changes in the dim-light control group, the bright-light group had significant 2-hour phase delays of circadian temperature and melatonin rhythm. Compared to pretreatment measures, over the 4-week follow-up period, the bright-light group had a greater reduction of time awake after sleep onset, showed a trend toward waking later, and had a greater increase of total sleep time. Participants in the bright-light condition also tended to report greater reductions of negative daytime symptoms, including significantly fewer days of feeling depressed at the 4-week follow-up, as compared with the control group. Two evenings of bright-light exposure phase delayed the circadian rhythms of early-morning awakening insomniacs. It also improved diary and actigraphy sleep measures and improved some indexes of daytime functioning for up to 1 month after light exposure. The study suggests that a brief course of evening bright-light therapy can be an effective treatment for early-morning awakening insomniacs who have relatively phase advanced circadian rhythms.

Intersection Monitor for Traffic-Light-Preemption System

NASA Technical Reports Server (NTRS)

Bachelder, Aaron; Foster, Conrad

2006-01-01

The figure shows an intersection monitor that is a key subsystem of an emergency traffic-light-preemption system that could be any of the systems described in the three immediately preceding articles and in Systems Would Preempt Traffic Lights for Emergency Vehicles (NPO-30573), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 36. This unit is so named because it is installed at an intersection, where it monitors the phases (in the sense of timing) of the traffic lights. The mode of operation of this monitor is independent of the type of traffic-light-controller hardware or software in use at the intersection. Moreover, the design of the monitor is such that (1) the monitor does not, by itself, affect the operation of the traffic- light controller and (2) in the event of a failure of the monitor, the trafficlight controller continues to function normally (albeit without preemption). The monitor is installed in series with the traffic-light controller at an intersection. The control signals of interest are monitored by use of high-impedance taps on affected control lines. These taps are fully isolated and further protected by high-voltage diodes that prevent any voltages or short circuits that arise within the monitor from affecting the controller. The signals from the taps are processed digitally and cleaned up by use of high-speed logic gates, and the resulting data are passed on to other parts of the traffic-light-preemption intersection subsystem. The data are compared continuously with data from vehicles and used to calculate timing for reliable preemption of the traffic lights. The pedestrian crossing at the intersection is also monitored, and pedestrians are warned not to cross during preemption.

Light-Induced Capacitance Tunability in Ferroelectric Crystals.

PubMed

Páez-Margarit, David; Rubio-Marcos, Fernando; Ochoa, Diego A; Del Campo, Adolfo; Fernández, José F; García, José E

2018-06-25

The remote controlling of ferroic properties with light is nowadays a hot and highly appealing topic in materials science. Here, we shed light on some of the unresolved issues surrounding light-matter coupling in ferroelectrics. Our findings show that the capacitance and, consequently, its related intrinsic material property, i.e., the dielectric constant, can be reversibly adjusted through the light power control. High photodielectric performance is exhibited across a wide range of the visible light wavelength because of the wavelength-independence of the phenomenon. We have verified that this counterintuitive behavior can be strongly ascribed to the existence of "locally free charges" at domain wall.

Dynamic Optical Grating Device and Associated Method for Modulating Light

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Chu, Sang-Hyon (Inventor)

2012-01-01

A dynamic optical grating device and associated method for modulating light is provided that is capable of controlling the spectral properties and propagation of light without moving mechanical components by the use of a dynamic electric and/or magnetic field. By changing the electric field and/or magnetic field, the index of refraction, the extinction coefficient, the transmittivity, and the reflectivity fo the optical grating device may be controlled in order to control the spectral properties of the light reflected or transmitted by the device.

Adapting Wireless Technology to Lighting Control and Environmental Sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dana Teasdale; Francis Rubinstein; David S. Watson

Although advanced lighting control systems offer significant energy savings, the high cost of retrofitting buildings with advanced lighting control systems is a barrier to adoption of this energy-saving technology. Wireless technology, however, offers a solution to mounting installation costs since it requires no additional wiring to implement. To demonstrate the feasibility of such a system, a prototype wirelessly-controlled advanced lighting system was designed and built. The system includes the following components: a wirelessly-controllable analog circuit module (ACM), a wirelessly-controllable electronic dimmable ballast, a T8 3-lamp fixture, an environmental multi-sensor, a current transducer, and control software. The ACM, dimmable ballast, multi-sensor,more » and current transducer were all integrated with SmartMesh{trademark} wireless mesh networking nodes, called motes, enabling wireless communication, sensor monitoring, and actuator control. Each mote-enabled device has a reliable communication path to the SmartMesh Manager, a single board computer that controls network functions and connects the wireless network to a PC running lighting control software. The ACM is capable of locally driving one or more standard 0-10 Volt electronic dimmable ballasts through relay control and a 0-10 Volt controllable output, in addition to 0-24 Volt and 0-10 Volt inputs. The mote-integrated electronic dimmable ballast is designed to drive a standard 3-lamp T8 light fixture. The environmental multisensor measures occupancy, light level and temperature. The current transducer is used to measure the power consumed by the fixture. Control software was developed to implement advanced lighting algorithms, including open and closed-loop daylight ramping, occupancy control, and demand response. Engineering prototypes of each component were fabricated and tested in a bench-scale system. Based on standard industry practices, a cost analysis was conducted. It is estimated that the installation cost of a wireless advanced lighting control system for a retrofit application is at least 20% lower than a comparable wired system for a typical 16,000 square-foot office building, with a payback period of less than 3 years. At 30% market penetration saturation, a cumulative 695 Billion kWh of energy could be saved through 2025, a cost savings of $52 Billion.« less

Degree of conversion of two lingual retainer adhesives cured with different light sources.

PubMed

Usümez, Serdar; Büyükyilmaz, Tamer; Karaman, Ali Ihya; Gündüz, Beniz

2005-04-01

The aim of this study was to evaluate the degree of conversion (DC) of two lingual retainer adhesives, Transbond Lingual Retainer (TLR) and Light Cure Retainer (LCR), cured with a fast halogen light, a plasma arc light and a light-emitting diode (LED) at various curing times. A conventional halogen light served as the control. One hundred adhesive samples (five per group) were cured for 5, 10 or 15 seconds with an Optilux 501 (fast halogen light), for 3, 6 or 9 seconds with a Power Pac (plasma arc light), or for 10, 20 or 40 seconds with an Elipar Freelight (LED). Samples cured for 40 seconds with the conventional halogen lamp were used as the controls. Absorbance peaks were recorded using Fourier transform infrared (FT-IR) spectroscopy. DC values were calculated. Data were analysed using Kruskal-Wallis and Mann-Whitney U-tests. For the TLR, the highest DC values were achieved in 6 and 9 seconds with the plasma arc light. Curing with the fast halogen light for 15 seconds and with the LED for 40 seconds produced statistically similar DC values, but these were lower than those with the plasma arc light. All of these light exposures yielded a statistically significantly higher DC than 40 seconds of conventional halogen light curing. The highest DC value for the LCR was achieved in 15 seconds with the fast halogen light, then the plasma arc light curing for 6 seconds. These two combinations produced a statistically significantly higher DC when compared with the 40 seconds of conventional halogen light curing. The lowest DC for the LCR was achieved with 10 seconds of LED curing. The overall DC of the LCR was significantly higher than that of the TLR. The results suggest that a similar or higher DC than the control values could be achieved in 6-9 seconds by plasma arc curing, in 10-15 seconds by fast halogen curing or in 20 seconds by LED curing.

40 CFR 86.1818-12 - Greenhouse gas emission standards for light-duty vehicles, light-duty trucks, and medium-duty...

Code of Federal Regulations, 2014 CFR

2014-07-01

...-equivalent debits for a test group using an alternative N2O or CH4 standard; GWP = 25 if calculating CH4...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and Complete Otto...

Cascading effects of artificial light at night: resource-mediated control of herbivores in a grassland ecosystem

PubMed Central

Bennie, Jonathan; Davies, Thomas W.; Cruse, David; Inger, Richard; Gaston, Kevin J.

2015-01-01

Artificial light at night has a wide range of biological effects on both plants and animals. Here, we review mechanisms by which artificial light at night may restructure ecological communities by modifying the interactions between species. Such mechanisms may be top-down (predator, parasite or grazer controlled), bottom-up (resource-controlled) or involve non-trophic processes, such as pollination, seed dispersal or competition. We present results from an experiment investigating both top-down and bottom-up effects of artificial light at night on the population density of pea aphids Acyrthosiphon pisum in a diverse artificial grassland community in the presence and absence of predators and under low-level light of different spectral composition. We found no evidence for top-down control of A. pisum in this system, but did find evidence for bottom-up effects mediated through the impact of light on flower head density in a leguminous food plant. These results suggest that physiological effects of light on a plant species within a diverse plant community can have detectable demographic effects on a specialist herbivore. PMID:25780243

NASA Lighting Research, Test, & Analysis

NASA Technical Reports Server (NTRS)

Clark, Toni

2015-01-01

The Habitability and Human Factors Branch, at Johnson Space Center, in Houston, TX, provides technical guidance for the development of spaceflight lighting requirements, verification of light system performance, analysis of integrated environmental lighting systems, and research of lighting-related human performance issues. The Habitability & Human Factors Lighting Team maintains two physical facilities that are integrated to provide support. The Lighting Environment Test Facility (LETF) provides a controlled darkroom environment for physical verification of lighting systems with photometric and spetrographic measurement systems. The Graphics Research & Analysis Facility (GRAF) maintains the capability for computer-based analysis of operational lighting environments. The combined capabilities of the Lighting Team at Johnson Space Center have been used for a wide range of lighting-related issues.

Do Wild Great Tits Avoid Exposure to Light at Night?

PubMed Central

de Jong, Maaike; Ouyang, Jenny Q.; van Grunsven, 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 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. PMID:27355354

Herbivores and nutrients control grassland plant diversity via light limitation

USGS Publications Warehouse

Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

2014-01-01

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Herbivores and nutrients control grassland plant diversity via light limitation.

PubMed

Borer, Elizabeth T; Seabloom, Eric W; Gruner, Daniel S; Harpole, W Stanley; Hillebrand, Helmut; Lind, Eric M; Adler, Peter B; Alberti, Juan; Anderson, T Michael; Bakker, Jonathan D; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S; Brudvig, Lars A; Buckley, Yvonne M; Cadotte, Marc; Chu, Chengjin; Cleland, Elsa E; Crawley, Michael J; Daleo, Pedro; Damschen, Ellen I; Davies, Kendi F; DeCrappeo, Nicole M; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A; Knops, Johannes M H; La Pierre, Kimberly J; Leakey, Andrew D B; Li, Wei; MacDougall, Andrew S; McCulley, Rebecca L; Melbourne, Brett A; Mitchell, Charles E; Moore, Joslin L; Mortensen, Brent; O'Halloran, Lydia R; Orrock, John L; Pascual, Jesús; Prober, Suzanne M; Pyke, David A; Risch, Anita C; Schuetz, Martin; Smith, Melinda D; Stevens, Carly J; Sullivan, Lauren L; Williams, Ryan J; Wragg, Peter D; Wright, Justin P; Yang, Louie H

2014-04-24

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Light-induced protein degradation in human-derived cells.

PubMed

Sun, Wansheng; Zhang, Wenyao; Zhang, Chao; Mao, Miaowei; Zhao, Yuzheng; Chen, Xianjun; Yang, Yi

2017-05-27

Controlling protein degradation can be a valuable tool for posttranslational regulation of protein abundance to study complex biological systems. In the present study, we designed a light-switchable degron consisting of a light oxygen voltage (LOV) domain of Avena sativa phototropin 1 (AsLOV2) and a C-terminal degron. Our results showed that the light-switchable degron could be used for rapid and specific induction of protein degradation in HEK293 cells by light in a proteasome-dependent manner. Further studies showed that the light-switchable degron could also be utilized to mediate the degradation of secreted Gaussia princeps luciferase (GLuc), demonstrating the adaptability of the light-switchable degron in different types of protein. We suggest that the light-switchable degron offers a robust tool to control protein levels and may serves as a new and significant method for gene- and cell-based therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of light pollution on the emergent fauna of shallow marine ecosystems: Amphipods as a case study.

PubMed

Navarro-Barranco, Carlos; Hughes, Lauren Elizabeth

2015-05-15

Light pollution from coastal urban development is a widespread and increasing threat to biodiversity. Many amphipod species migrate between the benthos and the pelagic environment and light seems is a main ecological factor which regulates migration. We explore the effect of artificial lighting on amphipod assemblages using two kind of lights, LED and halogen, and control traps in shallow waters of the Great Barrier Reef. Both types of artificial light traps showed a significantly higher abundance of individuals for all species in comparison to control traps. LED lights showed a stronger effect over the amphipod assemblages, with these traps collecting a higher number of individuals and differing species composition, with some species showing a specific attraction to LED light. As emergent amphipods are a key ecological group in the shallow water environment, the impact of artificial light can affect the broader functioning of the ecosystem. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multi-Level Light Capture Control in Plants and Green Algae.

PubMed

Wobbe, Lutz; Bassi, Roberto; Kruse, Olaf

2016-01-01

Life on Earth relies on photosynthesis, and the ongoing depletion of fossil carbon fuels has renewed interest in phototrophic light-energy conversion processes as a blueprint for the conversion of atmospheric CO2 into various organic compounds. Light-harvesting systems have evolved in plants and green algae, which are adapted to the light intensity and spectral composition encountered in their habitats. These organisms are constantly challenged by a fluctuating light supply and other environmental cues affecting photosynthetic performance. Excess light can be especially harmful, but plants and microalgae are equipped with different acclimation mechanisms to control the processing of sunlight absorbed at both photosystems. We summarize the current knowledge and discuss the potential for optimization of phototrophic light-energy conversion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Diffraction-Based Optical Switch

NASA Technical Reports Server (NTRS)

Sperno, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

2005-01-01

Method and system for controllably redirecting a light beam, having a central wavelength lambda, from a first light-receiving site to a second light-receiving site. A diffraction grating is attached to or part of a piezoelectric substrate, which is connected to one or two controllable voltage difference sources. When a substrate voltage difference is changed and the diffraction grating length in each of one or two directions is thereby changed, at least one of the diffraction angle, the diffraction order and the central wavelength is controllably changed. A diffracted light beam component, having a given wavelength, diffraction angle and diffraction order, that is initially received at a first light receiving site (e.g., a detector or optical fiber) is thereby controllably shifted or altered and can be received at a second light receiving site. A polynomially stepped, chirped grating is used in one embodiment. In another embodiment, an incident light beam, having at least one of first and second wavelengths, lambda1 and lambda2, is received and diffracted at a first diffraction grating to provide a first diffracted beam. The first diffracted beam is received and diffracted at a second diffraction grating to produce a second diffracted beam. The second diffracted beam is received at a light-sensitive transducer, having at least first and second spaced apart light detector elements that are positioned so that, when the incident light beam has wavelength lambda1 or lambda2 (lambda1 not equal to lambda2), the second diffracted beam is received at the first element or at the second element, respectively; change in a selected physical parameter at the second grating can also be sensed or measured. A sequence of spaced apart light detector elements can be positioned along a linear or curvilinear segment with equal or unequal spacing.

Table lamp with dynamically controlled lighting distribution and uniformly illuminated luminous shade

DOEpatents

Siminovitch, Michael J.; Page, Erik R.

2002-01-01

A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) or other lamps arranged vertically, i.e. one lamp above the other, with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum ensures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. In a particular configuration, the reflective septum is bowl shaped, with the upper CFL sitting in the bowl, and a luminous shade hanging down from the bowl. The lower CFL provides both task lighting and uniform shade luminance. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. However, other types of lamps, including incandescent, halogen, and LEDs can also be used in the fixture. The lighting system may be designed for the home, hospitality, office or other environments.

Reducing Barriers To The Use of High-Efficiency Lighting Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peter Morante

2005-12-31

With funding from the U.S. Department of Energy (DOE), the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute completed the four-year research project, Reducing Barriers to the Use of High-Efficiency Lighting Systems. The initial objectives were: (1) identifying barriers to widespread penetration of lighting controls in commercial/industrial (C/I) applications that employ fluorescent lamp technologies, and (2) making recommendations to overcome these barriers. The addition of a fourth year expanded the original project objectives to include an examination of the impact on fluorescent lamps from dimming utilizing different lamp electrode heating and dimming ratios. The scope of the project was narrowedmore » to identify barriers to the penetration of lighting controls into commercial-industrial (C/I) applications that employ fluorescent lamp technologies, and to recommend means for overcoming these barriers. Working with lighting manufacturers, specifiers, and installers, the project identified technological and marketing barriers to the widespread use of lighting controls, specifically automatic-off controls, occupancy sensors, photosensors, dimming systems, communication protocols and load-shedding ballasts. The primary barriers identified include cost effectiveness of lighting controls to the building owner, lack of standard communication protocols to allow different part of the control system to communicate effectively, and installation and commissioning issues. Overcoming the identified barriers requires lighting control products on the market to achieve three main goals: (1) Achieve sufficient functionality to meet the key requirements of their main market. (2) Allow significant cost reduction compared to current market standard systems. Cost should consider: hardware capital cost including wiring, design time required by the specifier and the control system manufacturer, installation time required by the electrician, and commissioning time and remedial time required by the electrician and end user. (3) Minimize ongoing perceived overhead costs and inconvenience to the end user, or in other words, systems should be simple to understand and use. In addition, we believe that no lighting controls solution is effective or acceptable unless it contributes to, or does not compromise, the following goals: (1) Productivity--Planning, installation, commissioning, maintenance, and use of controls should not decrease business productivity; (2) Energy savings--Lighting controls should save significant amounts of energy and money in relation to the expense involved in using them (acceptable payback period); and/or (3) Reduced power demand--Society as a whole should benefit from the lowered demand for expensive power and for more natural resources. Discussions of technology barriers and developments are insufficient by themselves to achieve higher penetration of lighting controls in the market place. Technology transfer efforts must play a key role in gaining market acceptance. The LRC developed a technology transfer model to better understand what actions are required and by whom to move any technology toward full market acceptance.« less

Arbitrary helicity control of circularly polarized light from lateral-type spin-polarized light-emitting diodes at room temperature

NASA Astrophysics Data System (ADS)

Nishizawa, Nozomi; Aoyama, Masaki; Roca, Ronel C.; Nishibayashi, Kazuhiro; Munekata, Hiro

2018-05-01

We demonstrate arbitrary helicity control of circularly polarized light (CPL) emitted at room temperature from the cleaved side facet of a lateral-type spin-polarized light-emitting diode (spin-LED) with two ferromagnetic electrodes in an antiparallel magnetization configuration. Driving alternate currents through the two electrodes results in polarization switching of CPL with frequencies up to 100 kHz. Furthermore, tuning the current density ratio in the two electrodes enables manipulation of the degree of circular polarization. These results demonstrate arbitrary electrical control of polarization with high speed, which is required for the practical use of lateral-type spin-LEDs as monolithic CPL light sources.

Adapting Wireless Technology to Lighting Control and Environmental Sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dana Teasdale; Francis Rubinstein; Dave Watson

The high cost of retrofitting buildings with advanced lighting control systems is a barrier to adoption of this energy-saving technology. Wireless technology, however, offers a solution to mounting installation costs since it requires no additional wiring to implement. To demonstrate the feasibility of such a system, a prototype wirelessly-controlled advanced lighting system was designed and built. The system includes the following components: a wirelessly-controllable analog circuit module (ACM), a wirelessly-controllable electronic dimmable ballast, a T8 3-lamp fixture, an environmental multi-sensor, a current transducer, and control software. The ACM, dimmable ballast, multi-sensor, and current transducer were all integrated with SmartMesh{trademark} wirelessmore » mesh networking nodes, called motes, enabling wireless communication, sensor monitoring, and actuator control. Each mote-enabled device has a reliable communication path to the SmartMesh Manager, a single board computer that controls network functions and connects the wireless network to a PC running lighting control software. The ACM is capable of locally driving one or more standard 0-10 Volt electronic dimmable ballasts through relay control and a 0-10 Volt controllable output. The mote-integrated electronic dimmable ballast is designed to drive a standard 3-lamp T8 light fixture. The environmental multi-sensor measures occupancy, light level and temperature. The current transducer is used to measure the power consumed by the fixture. Control software was developed to implement advanced lighting algorithms, including daylight ramping, occupancy control, and demand response. Engineering prototypes of each component were fabricated and tested in a bench-scale system. Based on standard industry practices, a cost analysis was conducted. It is estimated that the installation cost of a wireless advanced lighting control system for a retrofit application is at least 30% lower than a comparable wired system for a typical 16,000 square-foot office building, with a payback period of less than 3 years.« less

Impact of light exposure on thyroid-stimulating hormone results using the Siemens Advia Centaur TSH-3Ultra assay.

PubMed

Armer, Jane; Giles, Diane; Lancaster, Ian; Brownbill, Kathryn

2017-09-01

Background Thyroid-stimulating hormone (TSH) is used as the first-line test of thyroid function. Siemens Healthcare Diagnostics recommend that Siemens Centaur reagents must be protected from light in the assay information and on reagent packaging. We have compared the effect of light exposure on results using Siemens TSH-3Ultra and follicle-stimulating hormone reagents. The thyroid-stimulating hormone reagent includes fluoroscein thiocyanate whereas the follicle-stimulating hormone reagent does not. Methods Three levels of quality controls were analysed using SiemensTSH-3Ultra and follicle-stimulating hormone reagent packs that had been kept protected from light or exposed to light at 6-h intervals for 48 h and then at 96 h. Results Thyroid-stimulating hormone results were significantly lower after exposure of TSH-3Ultra reagent packs to light. Results were >15% lower at all three levels of quality control following 18 h of light exposure and continued to decrease until 96 h. There was no significant difference in follicle-stimulating hormone results whether reagents had been exposed to or protected from light. Conclusions Thyroid-stimulating hormone results but not follicle-stimulating hormone results are lowered after exposure of reagent packs to light. Laboratories must ensure that TSH-3Ultra reagents are not exposed to light and analyse quality control samples on every reagent pack to check that there has not been light exposure prior to delivery. The labelling on TSH-3Ultra reagent packs should reflect the significant effect of light exposure compared with the follicle-stimulating hormone reagent. We propose that the effect of light exposure on binding of fluoroscein thiocyanate to the solid phase antibody causes the falsely low results.

Optical control of resonant light transmission for an atom-cavity system

NASA Astrophysics Data System (ADS)

Sharma, Arijit; Ray, Tridib; Sawant, Rahul V.; Sheikholeslami, G.; Rangwala, S. A.; Budker, D.

2015-04-01

We demonstrate the manipulation of transmitted light through an optical Fabry-Pérot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the 87RbD2 (F =2 ,F =1 ) ↔F' manifold is controlled by the transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of the cavity-mode control is the precipitous destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity on intersection of the transverse control beam with the cavity mode. Both the steady-state and transient responses are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief.

Controls for and constraints on auto-shaping

PubMed Central

Bilbrey, John; Winokur, Stephen

1973-01-01

Auto-shaping the pigeon's key-peck response was examined as a respondent conditioning procedure with the use of Rescorla's truly-random control procedure. In the first experiment, pigeons received presentations of brief light on the response key and brief presentations of food where the light and the food were independently presented. All birds failed to key peck after many light and food presentations, but explicit pairing of the light and food rapidly conditioned pecking to the light. Experiment 2 showed that even when an independent light/food presentation schedule was reduced to variable-time 30 sec, additional naive birds would not key peck and only one bird pecked when the schedules were variable-time 15 sec. A third experiment examined an explicit-unpairing control procedure, where the light and food were not only presented on independent schedules but were also separated by a minimum time, and found that auto-shaping did not occur. A fourth experiment investigated a number of control procedures and found them ineffective. A fifth experiment investigated the effects of a physical separation of the locus of the response key and the food dispenser, and a sixth experiment investigated using a tone in place of the light. It was concluded that pecking is generated by auto-shaping procedures only when an intermittently presented keylight is regularly paired with food. PMID:16811710

Light qualities and dose influence ascorbate pool size in detached oat leaves.

PubMed

Mastropasqua, Linda; Borraccino, Giuseppe; Bianco, Laura; Paciolla, Costantino

2012-02-01

In this work, we studied the mechanism of light influence on AsA pool size in Avena sativa L. under the effects of low intensity light at different wavelengths. Exposure to low intensity light of oat leaf segments incubated in water or in l-galactono-1,4-lactone (GL), resulted in an increase in AsA content compared with the dark control. This increase was due to modulation of l-galactono-1,4-lactone dehydrogenase (GLDH; EC 1.3.2.3) light-dependent activity and was dependent on the size of the endogenous GL pool. Both blue and red light were effective in increasing AsA, and this increase depended on both exposure time and light intensity. Protein biosynthesis, photosynthesis and calcium were involved in controlling the level of light-dependent AsA. We suggest that multiple checkpoints correlated to the presence of light underlie the ascorbate pool size. The presence of a light-activated switch for the maintenance of an adequate AsA level seems to be necessary for the various tasks of scavenging reactive oxygen species, in response to the dark-light cycle which plants experience under natural conditions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

LED Context Lighting System in Residential Areas

PubMed Central

Im, Kyoung-Mi

2014-01-01

As issues of environment and energy draw keen interest around the globe due to such problems as global warming and the energy crisis, LED with high optical efficiency is brought to the fore as the next generation lighting. In addition, as the national income level gets higher and life expectancy is extended, interest in the enhancement of life quality is increasing. Accordingly, the trend of lightings is changing from mere adjustment of light intensity to system lighting in order to enhance the quality of one's life as well as reduce energy consumption. Thus, this study aims to design LED context lighting system that automatically recognizes the location and acts of a user in residential areas and creates an appropriate lighting environment. The proposed system designed in this study includes three types of processing: first, the creation of a lighting environment index suitable for the user's surroundings and lighting control scenarios and second, it measures and analyzes the optical characteristics that change depending on the dimming control of lighting and applies them to the index. Lastly, it adopts PIR, piezoelectric, and power sensor to grasp the location and acts of the user and create a lighting environment suitable for the current context. PMID:25101325

Lifelog-based lighting design for biofied building

NASA Astrophysics Data System (ADS)

Kake, Fumika; Mita, Akira

2016-04-01

A design tool is proposed for lighting control system that reflects histories of residents' past life using a genetic mechanism. There are many previous researches which show the preference of lighting design differs depending on people and their behaviors. And recently, due to the appearance of LED which can change light color easily, the number of lighting scenes have drastically increased. It is difficult for residents to grasp all patterns of lighting and understand what pattern of lighting design fits for their behaviors. So if we can extract lighting preferences and demands of each resident from histories of past life and reflect these information in next lighting control, it's possible to make living space more comfortable. An evolutionally adaptation mechanism learnt from living organisms is proposed in this research to extract the information from lifelog, especially focusing on methylation and mutation. Methylation is one of the epigenetic algorithms making a difference in phenotype without changing DNA sequence. Mutation is one of the genetic algorithms making a difference in phenotype by changing DNA sequence. Those two mechanisms are applied in the system. First, the lifelog of residents and using hysteresis of lighting equipment are collected. Then the lifelog is converted into the genetic information and stored. When the lifelog is stored enough, the superior genes will be picked up from the stored genetic information to be reflected in lighting control in next generation. Simulations to verify the versatility of the system were conducted.

Development of a circadian light source

NASA Astrophysics Data System (ADS)

Nicol, David B.; Ferguson, Ian T.

2002-11-01

Solid state lighting presents a new paradigm for lighting - controllability. Certain characteristics of the lighting environment can be manipulated, because of the possibility of using multiple LEDs of different emission wavelengths as the illumination source. This will provide a new, versatile, general illumination source due to the ability to vary the spectral power distribution. New effects beyond the visual may be achieved that are not possible with conventional light sources. Illumination has long been the primary function of lighting but as the lighting industry has matured the psychological aspects of lighting have been considered by designers; for example, choosing a particular lighting distribution or color variation in retail applications. The next step in the evolution of light is to consider the physiological effects of lighting that cause biological changes in a person within the environment. This work presents the development of a source that may have important bearing on this area of lighting. A circadian light source has been developed to provide an illumination source that works by modulating its correlated color temperature to mimic the changes in natural daylight through the day. In addition, this source can cause or control physiological effects for a person illuminated by it. The importance of this is seen in the human circadian rhythm's peak response corresponding to blue light at ~460 nm which corresponds to the primary spectral difference in increasing color temperature. The device works by adding blue light to a broadband source or mixing polychromatic light to mimic the variation of color temperature observed for the Planckian Locus on the CIE diagram. This device can have several applications including: a tool for researchers in this area, a general illumination lighting technology, and a light therapy device.

Lighting: Green Light.

ERIC Educational Resources Information Center

Maniccia, Dorine

2003-01-01

Explains that by using sustainable (green) building practices, schools and universities can make their lighting systems more efficient, noting that embracing green design principles can help schools attract students. Discusses lighting-control technologies (occupancy sensing technology, daylighting technology, and scheduling based technologies),…

Low Power Switching for Antenna Reconfiguration

NASA Technical Reports Server (NTRS)

Bauhahn, Paul E. (Inventor); Becker, Robert C. (Inventor); Meyers, David W. (Inventor); Muldoon, Kelly P. (Inventor)

2008-01-01

Methods and systems for low power switching are provided. In one embodiment, an optical switching system is provided. The system comprises at least one optically controlled switch adapted to maintain one of an open state and a closed state based on an associated light signal; and at least one light source adapted to output the associated light signal to the at least one switch, wherein the at least one light source cycles the light signal on and off, wherein the at least one light source is cycled on for a sufficient duration of time and with a sufficient periodicity to maintain the optically controlled switch in one of an open state and a closed state.

Light Effects on Behavioural Performance Depend on the Individual State of Vigilance

PubMed Central

Barba, Antonio; Padilla, Francisca

2016-01-01

Research has shown that exposure to bright white light or blue-enriched light enhances alertness, but this effect is not consistently observed in tasks demanding high-level cognition (e.g., Sustained Attention to Response Task—SART, which measures inhibitory control). Individual differences in sensitivity to light effects might be mediated by variations in the basal level of arousal. We tested this hypothesis by measuring the participants’ behavioural state of vigilance before light exposure, through the Psychomotor Vigilance Task. Then we compared the effects of a blue-enriched vs. dim light at nighttime on the performance of the auditory SART, by controlling for individual differences in basal arousal. The results replicated the alerting effects of blue-enriched light, as indexed by lower values of both proximal temperature and distal-proximal gradient. The main finding was that lighting effects on SART performance were highly variable across individuals and depended on their prior state of vigilance. Specifically, participants with higher levels of basal vigilance before light exposure benefited most from blue-enriched lighting, responding faster in the SART. These results highlight the importance of considering basal vigilance to define the boundary conditions of light effects on cognitive performance. Our study adds to current research delineating the complex and reciprocal interactions between lighting effects, arousal, cognitive task demands and behavioural performance. PMID:27820822

Light Effects on Behavioural Performance Depend on the Individual State of Vigilance.

PubMed

Correa, Ángel; Barba, Antonio; Padilla, Francisca

2016-01-01

Research has shown that exposure to bright white light or blue-enriched light enhances alertness, but this effect is not consistently observed in tasks demanding high-level cognition (e.g., Sustained Attention to Response Task-SART, which measures inhibitory control). Individual differences in sensitivity to light effects might be mediated by variations in the basal level of arousal. We tested this hypothesis by measuring the participants' behavioural state of vigilance before light exposure, through the Psychomotor Vigilance Task. Then we compared the effects of a blue-enriched vs. dim light at nighttime on the performance of the auditory SART, by controlling for individual differences in basal arousal. The results replicated the alerting effects of blue-enriched light, as indexed by lower values of both proximal temperature and distal-proximal gradient. The main finding was that lighting effects on SART performance were highly variable across individuals and depended on their prior state of vigilance. Specifically, participants with higher levels of basal vigilance before light exposure benefited most from blue-enriched lighting, responding faster in the SART. These results highlight the importance of considering basal vigilance to define the boundary conditions of light effects on cognitive performance. Our study adds to current research delineating the complex and reciprocal interactions between lighting effects, arousal, cognitive task demands and behavioural performance.

Dynamic generation and coherent control of beating stationary light pulses by a microwave coupling field in five-level cold atoms

NASA Astrophysics Data System (ADS)

Bao, Qian-Qian; Zhang, Yan; Cui, Cui-Li; Meng, Shao-Ying; Fang, You-Wei; Tian, Xue-Dong

2018-04-01

We propose an efficient scheme for generating and controlling beating stationary light pulses in a five-level atomic sample driven into electromagnetically induced transparency condition. This scheme relies on an asymmetrical procedure of light storage and retrieval tuned by two counter-propagating control fields where an additional coupling field, such as the microwave field, is introduced in the retrieval stage. A quantum probe field, incident upon such an atomic sample, is first transformed into spin coherence excitation of the atoms and then retrieved as beating stationary light pulses exhibiting a series of maxima and minima in intensity due to the alternative constructive and destructive interference. It is convenient to control the beating stationary light pulses just by manipulating the intensity and detuning of the additional microwave field. This interesting phenomenon involves in fact the coherent manipulation of dark-state polaritons and could be explored to achieve the efficient temporal splitting of stationary light pulses and accurate measurement of the microwave intensity.

Light Spectral Quality Effects on the Growth of Potato (Solanum Tuberosum L.) Nodal Cutttings in Vitro

NASA Technical Reports Server (NTRS)

Wilson, Deborah A.; Weigel, Russell, C.; Wheeler, Raymond M.; Sager, John C.

1993-01-01

The effects of light spectral quality on the growth of in vitro nodal cutting of potato (Solanum tuberosum) cultivars Norland, Superior, Kennebec, and Denali were examined. The different light spectra were provided by Vita-Lite fluorescent (VF) (a white light control), blue fluorescent (BF), red fluorescent (RF), low-pressure sodium (LPS), and a combination of low-pressure sodium plus cool-white fluorescent lamp (LPS/CWF). Results suggested that shoot morphologic development of in vitro grown potato plants can be controlled by controlling irradiant spectral quality.

Effect of LED Blue Light on Penicillium digitatum and Penicillium italicum Strains.

PubMed

Lafuente, María T; Alférez, Fernando

2015-11-01

Studies on the antimicrobial properties of light have considerably increased due in part to the development of resistance to actual control methods. This study investigates the potential of light-emitting diodes (LED) blue light for controlling Penicillium digitatum and Penicillium italicum. These fungi are the most devastating postharvest pathogens of citrus fruit and cause important losses due to contaminations and the development of resistant strains against fungicides. The effect of different periods and quantum fluxes, delaying light application on the growth and morphology of P. digitatum strains resistant and sensitive to fungicides, and P. italicum cultured at 20°C was examined. Results showed that blue light controls the growth of all strains and that its efficacy increases with the quantum flux. Spore germination was always avoided by exposing the cultures to high quantum flux (700 μmol m(-2) s(-1) ) for 18 h. Continuous light had an important impact on the fungus morphology and a fungicidal effect when applied at a lower quantum flux (120 μmol m(-2) s(-1) ) to a growing fungus. Sensitivity to light increased with mycelium age. Results show that blue light may be a tool for P. digitatum and P. italicum infection prevention during handling of citrus fruits. © 2015 The American Society of Photobiology.

Superstructures of chiral nematic microspheres as all-optical switchable distributors of light

PubMed Central

Aβhoff, Sarah J.; Sukas, Sertan; Yamaguchi, Tadatsugu; Hommersom, Catharina A.; Le Gac, Séverine; Katsonis, Nathalie

2015-01-01

Light technology is based on generating, detecting and controlling the wavelength, polarization and direction of light. Emerging applications range from electronics and telecommunication to health, defence and security. In particular, data transmission and communication technologies are currently asking for increasingly complex and fast devices, and therefore there is a growing interest in materials that can be used to transmit light and also to control the distribution of light in space and time. Here, we design chiral nematic microspheres whose shape enables them to reflect light of different wavelengths and handedness in all directions. Assembled in organized hexagonal superstructures, these microspheres of well-defined sizes communicate optically with high selectivity for the colour and chirality of light. Importantly, when the microspheres are doped with photo-responsive molecular switches, their chiroptical communication can be tuned, both gradually in wavelength and reversibly in polarization. Since the kinetics of the “on” and “off” switching can be adjusted by molecular engineering of the dopants and because the photonic cross-communication is selective with respect to the chirality of the incoming light, these photo-responsive microspheres show potential for chiroptical all-optical distributors and switches, in which wavelength, chirality and direction of the reflected light can be controlled independently and reversibly. PMID:26400584

Carambola optics for recycling of light.

PubMed

Leutz, Ralf; Fu, Ling; Ries, Harald

2006-04-20

Recycling of light allows the luminance (radiance) emitted by a light source to be increased at the cost of reducing the total luminous flux (radiant power). Recycling of light means returning part of the emitted light to the source, where part of it will escape absorption. An optical design that is suitable for multiple and controlled recycling is described. Carambola optics is named for its resemblance to star fruit. Several pairs of mirrors or prisms redirect light repeatedly onto the source, thus achieving multiple transits of the light through the source. This recycled light exits the carambola in the same phase space as light directly emitted and not recycled.

Advanced lighting guidelines: 1993. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eley, C.; Tolen, T.M.; Benya, J.R.

1993-12-31

The 1993 Advanced Lighting Guidelines document consists of twelve guidelines that provide an overview of specific lighting technologies and design application techniques utilizing energy-efficient lighting practice. Lighting Design Practice assesses energy-efficient lighting strategies, discusses lighting issues, and explains how to obtain quality lighting design and consulting services. Luminaires and Lighting Systems surveys luminaire equipment designed to take advantage of advanced technology lamp products and includes performance tables that allow for accurate estimation of luminaire light output and power input. The additional ten guidelines -- Computer-Aided Lighting Design, Energy-Efficient Fluorescent Ballasts, Full-Size Fluorescent Lamps, Compact Fluorescent Lamps, Tungsten-Halogen Lamps, Metal Halidemore » and HPS Lamps, Daylighting and Lumen Maintenance, Occupant Sensors, Time Scheduling Systems, and Retrofit Control Technologies -- each provide a product technology overview, discuss current products on the lighting equipment market, and provide application techniques. This document is intended for use by electric utility personnel involved in lighting programs, lighting designers, electrical engineers, architects, lighting manufacturers` representatives, and other lighting professionals.« less

Retinal endoilluminator toxicity of xenon and light-emitting diode (LED) light source: rabbit model.

PubMed

Aydin, Bahri; Dinç, Erdem; Yilmaz, S Necat; Altiparmak, U Emrah; Yülek, Fatma; Ertekin, Sevda; Yilmaz, Mustafa; Yakın, Mehmet

2014-09-01

This study evaluates retinal toxicity due to endoillumination with the light-emitting diode (LED) light source in comparison to endoillumination with xenon light source. Twenty-five eyes of 14 New Zealand pigmented rabbits were used in the study. The LED light (Omesis Medical Systems, Turkey) group was composed of 7 right eyes, while the other 7 right eyes constituted the xenon group (420 nm filter, 357mW/cm(2)) (Bright Star; DORC, Zuidland, Netherlands). Eleven untreated left eyes composed the control group. Twenty gauge pars plana incision 1.5 mm behind the limbus was performed in the right eyes. Twenty gauge bullet type fiberoptic endoilluminator was inserted into the eye from the incision without any pars plana vitrectomy. Fiberoptic endoilluminator was placed in such a way that it was directed toward visual streak of the rabbit retina with a 5 mm distance to retinal surface. Endoillumination was then applied for 20 min with a maximum light intensity for LED and xenon light. In left control eyes, no surgical procedure and no endoillumination were performed. One week after the endoillumination procedure, both eyes of the rabbits were enucleated following electroretinography. Sections stained with hematoxylin and eosin to evaluate morphologic changes. Retina tissues were assessed by active caspase-3 staining. There was no difference in the shape of the waveforms recorded in the eyes endoilluminated with LED light and xenon light sources compared to control eyes both before and after endoillumination application (p > 0.05). Microscopic evaluation of the retinas with hematoxylin and eosin staining demonstrated that all study groups have normal histologic properties similar to control group. No apoptosis positive cells were found within all sections in all groups. When the LED light source is used with maximum power and limited duration for endoillumination in rabbit eyes it does not produce phototoxic effects that may be detectable by electrophysiology and histology similar to xenon light.

Gravi- and photostimuli in moss protonema growth movements

NASA Astrophysics Data System (ADS)

Demkiv, O. T.; Kordyum, E. L.; Khorkavtsiv, Ya D.; Kardash, O. R.; Chaban, Ch. I.

Moss protonemal growth direction is controlled by at least three factors, photo-, gravi- and autotropism. It is possible to experimentally separate these factors and to control selectively their morphological appearance. In darkness protonema grow negatively gravitropically, and unilateral illumination initiated positive phototropism. Red light suppressed auto- and gravitropism, blue light suppressed only gravitropism. Green light allowed both gravi- and autotropism. The effect of light on gravitropism might involve changes in starch synthesis.

Literature survey for suppression of scattered light in large space telescopes

NASA Technical Reports Server (NTRS)

Tifft, W. G.; Fannin, B. B.

1973-01-01

A literature survey is presented of articles dealing with all aspects of predicting, measuring, and controlling unwanted scattered (stray) light. The survey is divided into four broad classifications: (1) existing baffle/telescope designs; (2) computer programs for the analysis/design of light suppression systems; (3) the mechanism, measurement, and control of light scattering; and (4) the advantages and problems introduced by the space environment for the operation of diffraction-limited optical systems.

Gravi- and photostimuli in moss protonema growth movements.

PubMed

Demkiv, O T; Kordyum, E L; Khorkavtsiv YaD; Kardash, O R; Chaban ChI

1998-01-01

Moss protonemal growth direction is controlled by at least three factors, photo-, gravi- and autotropism. It is possible to experimentally separate these factors and to control selectively their morphological appearance. In darkness protonema grow negatively gravitropically, and unilateral illumination initiated positive phototropism. Red light suppressed auto- and gravitropism, blue light suppressed only gravitropism. Green light allowed both gravi- and autotropism. The effect of light on gravitropism might involve changes in starch synthesis.

Depth-tunable three-dimensional display with interactive light field control

NASA Astrophysics Data System (ADS)

Xie, Songlin; Wang, Peng; Sang, Xinzhu; Li, Chenyu; Dou, Wenhua; Xiao, Liquan

2016-07-01

A software-defined depth-tunable three-dimensional (3D) display with interactive 3D depth control is presented. With the proposed post-processing system, the disparity of the multi-view media can be freely adjusted. Benefiting from a wealth of information inherently contains in dense multi-view images captured with parallel arrangement camera array, the 3D light field is built and the light field structure is controlled to adjust the disparity without additional acquired depth information since the light field structure itself contains depth information. A statistical analysis based on the least square is carried out to extract the depth information inherently exists in the light field structure and the accurate depth information can be used to re-parameterize light fields for the autostereoscopic display, and a smooth motion parallax can be guaranteed. Experimental results show that the system is convenient and effective to adjust the 3D scene performance in the 3D display.

Introduction to the Solid State Based Interior Lighting System for ISS

NASA Technical Reports Server (NTRS)

Maida, James C.

2014-01-01

Solid state lighting assembly (SSLA) were designed to replace general luminaire assembly (GLA) for both general interior illumination and improved circadian rhythm through melatonin control using multiple spectrums. To accomplish these goals, the light is design to operate in 3 modes with 3 distinct spectrum. The different spectrum provide control of the blue portion of the light which impacts melatonin production in humans which impacts sleep. General mode is a 4500K "neutral" light spectrum intended to the be the default mode of operation for day to day operations. Pre-sleep mode is a 2700K "warm" light spectrum intended to be used by the crew at the end of the work day. Phase-shift mode is a 6500K "cool" light spectrum intended to be used for altering the crew's sleep patterns.

Simulating and evaluating an adaptive and integrated traffic lights control system for smart city application

NASA Astrophysics Data System (ADS)

Djuana, E.; Rahardjo, K.; Gozali, F.; Tan, S.; Rambung, R.; Adrian, D.

2018-01-01

A city could be categorized as a smart city when the information technology has been developed to the point that the administration could sense, understand, and control every resource to serve its people and sustain the development of the city. One of the smart city aspects is transportation and traffic management. This paper presents a research project to design an adaptive traffic lights control system as a part of the smart system for optimizing road utilization and reducing congestion. Research problems presented include: (1) Congestion in one direction toward an intersection due to dynamic traffic condition from time to time during the day, while the timing cycles in traffic lights system are mostly static; (2) No timing synchronization among traffic lights in adjacent intersections that is causing unsteady flows; (3) Difficulties in traffic condition monitoring on the intersection and the lack of facility for remotely controlling traffic lights. In this research, a simulator has been built to model the adaptivity and integration among different traffic lights controllers in adjacent intersections, and a case study consisting of three sets of intersections along Jalan K. H. Hasyim Ashari has been simulated. It can be concluded that timing slots synchronization among traffic lights is crucial for maintaining a steady traffic flow.

Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity.

PubMed

Baird, Emily; Fernandez, Diana C; Wcislo, William T; Warrant, Eric J

2015-01-01

Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion-a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta's flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta's adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus.

Flight control and landing precision in the nocturnal bee Megalopta is robust to large changes in light intensity

PubMed Central

Baird, Emily; Fernandez, Diana C.; Wcislo, William T.; Warrant, Eric J.

2015-01-01

Like their diurnal relatives, Megalopta genalis use visual information to control flight. Unlike their diurnal relatives, however, they do this at extremely low light intensities. Although Megalopta has developed optical specializations to increase visual sensitivity, theoretical studies suggest that this enhanced sensitivity does not enable them to capture enough light to use visual information to reliably control flight in the rainforest at night. It has been proposed that Megalopta gain extra sensitivity by summing visual information over time. While enhancing the reliability of vision, this strategy would decrease the accuracy with which they can detect image motion—a crucial cue for flight control. Here, we test this temporal summation hypothesis by investigating how Megalopta's flight control and landing precision is affected by light intensity and compare our findings with the results of similar experiments performed on the diurnal bumblebee Bombus terrestris, to explore the extent to which Megalopta's adaptations to dim light affect their precision. We find that, unlike Bombus, light intensity does not affect flight and landing precision in Megalopta. Overall, we find little evidence that Megalopta uses a temporal summation strategy in dim light, while we find strong support for the use of this strategy in Bombus. PMID:26578977

Light-emitting Diode Blue Light Alters the Ability of Penicillium digitatum to Infect Citrus Fruits.

PubMed

Lafuente, María T; Alférez, Fernando; González-Candelas, Luis

2018-04-27

Penicillium digitatum (Pers.:Fr.) Sacc. is the main fungus causing postharvest losses in citrus fruits. Previous work showed the potential of LED blue light (LBL) in controlling P. digitatum growth. Here, we have investigated whether LBL alters the ability of this fungus to infect citrus fruits. Before fruit infection, Petri plates inoculated with the same conidia concentration were held under darkness (control) or LBL (100 μmol m -2 s -1 ) for 8 d (continuous light), or were treated with the same LBL for 3 d and then shifted to darkness for 5 d (non-continuous light). Spores from cultures exposed to continuous light showed very low capacity to germinate (1.8% respect to control) but a high viability and a similar morphology and ability to infect the fruits than spores from control cultures. The number of spores produced in plates exposed to non-continuous light was slightly lower than in control plates, but they showed much lower viability and lower capacity to infect the fruits. This effect was more likely related to aberrant morphology of spores, which formed aggregates, than to its metabolic activity or its ability to produce ethylene that might contribute to destroy natural defense barriers from the fruit. © 2018 The American Society of Photobiology.

Electrowetting-driven solar indoor lighting (e-SIL): an optofluidic approach towards sustainable buildings.

PubMed

Thio, Si Kuan; Jiang, Dongyue; Park, Sung-Yong

2018-06-12

Optofluidics is an emerging research field that combines the two disciplines of microfluidics and optics. By using microfluidic technologies for light control, optofluidic devices can offer several advantages over solid-type optical components, including optical-grade smoothness at the fluidic interface and a high degree of optical tunability without bulky and complex mechanical moving parts. These features have made optofluidic devices more versatile and reconfigurable to improve their optical performances. In this paper, we present a novel optofluidic sunlight manipulation technology for solar indoor lighting using the electrowetting principle. Rooftop sunlight is collected by a solar concentrator and guided to individual rooms along an optical fiber (waveguide) on the bottom of which tunable liquid prisms are linearly integrated. In the light-off mode, electrowetting controls the apex angle of the prisms to be φ = 0°. Under this condition, incoming sunlight experiences total internal reflection and thus keeps propagating along the optical fiber without leaking to the prism bottom for indoor lighting. In contrast, when liquid prisms are controlled to have the angle at φ > 0°, incoming sunlight is partially transmitted to the bottom surface of the arrayed prisms to contribute to interior illumination. Simulation studies validate that our electrowetting-driven solar indoor lighting (e-SIL) system is capable of variably tuning the lighting power from 0% to 98.6% of the input solar power by controlling the prism angle and varying the refractive index of prism materials. For experimental studies, we fabricated an array of 5 prisms filled with silicone oil and water. Using a fiber illuminator as a white light source that includes visible light with various incident angles, we have demonstrated two important lighting functions, (1) light on/off and (2) illumination power control. Lighting performance can be further enhanced by lowering the aspect ratio of the prism as well as increasing the number of prisms. The e-SIL technology based on tunable liquid prisms offers a new approach towards sustainable buildings that are able to reduce their electricity usage as well as provide a healthy and comfortable indoor environment under illumination of natural sunlight.

40 CFR 85.2101 - General applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emissions Control System Performance Warranty Regulations and... through 85.2111 are applicable to all 1981 and later model year light-duty vehicles and light-duty trucks... apply to durability groups and test groups as applicable for manufacturers certifying new light-duty...

Optically programmable encoder based on light propagation in two-dimensional regular nanoplates.

PubMed

Li, Ya; Zhao, Fangyin; Guo, Shuai; Zhang, Yongyou; Niu, Chunhui; Zeng, Ruosheng; Zou, Bingsuo; Zhang, Wensheng; Ding, Kang; Bukhtiar, Arfan; Liu, Ruibin

2017-04-07

We design an efficient optically controlled microdevice based on CdSe nanoplates. Two-dimensional CdSe nanoplates exhibit lighting patterns around the edges and can be realized as a new type of optically controlled programmable encoder. The light source is used to excite the nanoplates and control the logical position under vertical pumping mode by the objective lens. At each excitation point in the nanoplates, the preferred light-propagation routes are along the normal direction and perpendicular to the edges, which then emit out from the edges to form a localized lighting section. The intensity distribution around the edges of different nanoplates demonstrates that the lighting part with a small scale is much stronger, defined as '1', than the dark section, defined as '0', along the edge. These '0' and '1' are the basic logic elements needed to compose logically functional devices. The observed propagation rules are consistent with theoretical simulations, meaning that the guided-light route in two-dimensional semiconductor nanoplates is regular and predictable. The same situation was also observed in regular CdS nanoplates. Basic theoretical analysis and experiments prove that the guided light and exit position follow rules mainly originating from the shape rather than material itself.

New Carrollton Federal Building Lighting Retrofit Captures Cool Savings

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2017-01-01

Case study describes how the U.S. General Services Administration cut a $291,000 annual lighting electric bill to an estimated $53,500 by upgrading their fluorescent lighting to a new LED troffer lighting and controls system in the New Carrollton Federal Building in Lanham, Maryland. The lighting project yielded an 82% reduction in energy use and earned GSA two awards for exemplary performance from the Interior Lighting Campaign in 2016.

Plasma melatonin circadian rhythms during the menstrual cycle and after light therapy in premenstrual dysphoric disorder and normal control subjects.

PubMed

Parry, B L; Berga, S L; Mostofi, N; Klauber, M R; Resnick, A

1997-02-01

The aim of this study was to replicate and extend previous work in which the authors observed lower, shorter, and advanced nocturnal melatonin secretion patterns in premenstrually depressed patients compared to those in healthy control women. The authors also sought to test the hypothesis that the therapeutic effect of bright light in patients was associated with corrective effects on the phase, duration, and amplitude of melatonin rhythms. In 21 subjects with premenstrual dysphoric disorder (PMDD) and 11 normal control (NC) subjects, the authors measured the circadian profile of melatonin during follicular and luteal menstrual cycle phases and after 1 week of light therapy administered daily, in a randomized crossover design. During three separate luteal phases, the treatments were either (1) bright (> 2,500 lux) white morning (AM; 06:30 to 08:30 h), (2) bright white evening (PM; 19:00 to 21:00 h), or (3) dim (< 10 lux) red evening light (RED). In PMDD subjects, during the luteal phase compared to the follicular menstrual cycle phase, melatonin onset time was delayed, duration was compressed, and area under the curve, amplitude, and mean levels were decreased. In NC subjects, melatonin rhythms did not change significantly during the menstrual cycle. After AM light in PMDD subjects, onset and offset times were advanced and both duration and midpoint concentration were decreased as compared to RED light. After PM light in PMDD subjects, onset and offset times were delayed, midpoint concentration was increased, and duration was decreased as compared to RED light. By contrast, after light therapy in NC subjects, duration did not change; onset, offset, and midpoint concentration changed as they did in PMDD subjects. When the magnitude of advance and delay phase shifts in onset versus offset time with AM, PM, or RED light were compared, the authors found that in PMDD subjects light shifted offset time more than onset time and that AM light had a greater effect on shifting melatonin offset time (measured the following night in RED light), whereas PM light had a greater effect in shifting melatonin onset time. These findings replicate the authors' previous observation that nocturnal melatonin concentrations are decreased in women with PMDD and suggest specific effects of light therapy on melatonin circadian rhythms that are associated with mood changes in patient versus control groups. The differential changes in onset and offset times during the menstrual cycle, and in response to AM and PM bright light compared with RED light, support a two-oscillator (complex) model of melatonin regulation in humans.

Independent polarisation control of multiple optical traps

PubMed Central

Preece, Daryl; Keen, Stephen; Botvinick, Elliot; Bowman, Richard; Padgett, Miles; Leach, Jonathan

2009-01-01

We present a system which uses a single spatial light modulator to control the spin angular momentum of multiple optical traps. These traps may be independently controlled both in terms of spatial location and in terms of their spin angular momentum content. The system relies on a spatial light modulator used in a “split-screen” configuration to generate beams of orthogonal polarisation states which are subsequently combined at a polarising beam splitter. Defining the phase difference between the beams with the spatial light modulator enables control of the polarisation state of the light. We demonstrate the functionality of the system by controlling the rotation and orientation of birefringent vaterite crystals within holographic optical tweezers. PMID:18825226

33 CFR 88.12 - Public safety activities.

Code of Federal Regulations, 2011 CFR

2011-07-01

...; traffic control; salvage; firefighting; medical assistance; assisting disabled vessels; and search and... alternately flashing red and yellow light signal. This identification light signal must be located so that it does not interfere with the visibility of the vessel's navigation lights. The identification light...

33 CFR 88.12 - Public safety activities.

Code of Federal Regulations, 2010 CFR

2010-07-01

...; traffic control; salvage; firefighting; medical assistance; assisting disabled vessels; and search and... alternately flashing red and yellow light signal. This identification light signal must be located so that it does not interfere with the visibility of the vessel's navigation lights. The identification light...

46 CFR 169.738 - Emergency lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Emergency lights. 169.738 Section 169.738 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.738 Emergency lights. Each emergency light...

46 CFR 169.738 - Emergency lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Emergency lights. 169.738 Section 169.738 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.738 Emergency lights. Each emergency light...

46 CFR 169.738 - Emergency lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Emergency lights. 169.738 Section 169.738 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.738 Emergency lights. Each emergency light...

46 CFR 169.738 - Emergency lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Emergency lights. 169.738 Section 169.738 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.738 Emergency lights. Each emergency light...

46 CFR 169.738 - Emergency lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Emergency lights. 169.738 Section 169.738 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.738 Emergency lights. Each emergency light...

Sleep deprivation decreases phase-shift responses of circadian rhythms to light in the mouse: role of serotonergic and metabolic signals.

PubMed

Challet, E; Turek, F W; Laute, M; Van Reeth, O

2001-08-03

The circadian pacemaker in the suprachiasmatic nuclei is primarily synchronized to the daily light-dark cycle. The phase-shifting and synchronizing effects of light can be modulated by non-photic factors, such as behavioral, metabolic or serotonergic cues. The present experiments examine the effects of sleep deprivation on the response of the circadian pacemaker to light and test the possible involvement of serotonergic and/or metabolic cues in mediating the effects of sleep deprivation. Photic phase-shifting of the locomotor activity rhythm was analyzed in mice transferred from a light-dark cycle to constant darkness, and sleep-deprived for 8 h from Zeitgeber Time 6 to Zeitgeber Time 14. Phase-delays in response to a 10-min light pulse at Zeitgeber Time 14 were reduced by 30% in sleep-deprived mice compared to control mice, while sleep deprivation without light exposure induced no significant phase-shifts. Stimulation of serotonin neurotransmission by fluoxetine (10 mg/kg), a serotonin reuptake inhibitor that decreases light-induced phase-delays in non-deprived mice, did not further reduce light-induced phase-delays in sleep-deprived mice. Impairment of serotonin neurotransmission with p-chloroamphetamine (three injections of 10 mg/kg), which did not increase light-induced phase-delays in non-deprived mice significantly, partially normalized light-induced phase-delays in sleep-deprived mice. Injections of glucose increased light-induced phase-delays in control and sleep-deprived mice. Chemical damage of the ventromedial hypothalamus by gold-thioglucose (600 mg/kg) prevented the reduction of light-induced phase-delays in sleep-deprived mice, without altering phase-delays in control mice. Taken together, the present results indicate that sleep deprivation can reduce the light-induced phase-shifts of the mouse suprachiasmatic pacemaker, due to serotonergic and metabolic changes associated with the loss of sleep.

Light Moderates the Induction of Phosphoenolpyruvate Carboxylase by NaCl and Abscisic Acid in Mesembryanthemum crystallinum 1

PubMed Central

McElwain, Elizabeth F.; Bohnert, Hans J.; Thomas, John C.

1992-01-01

In Mesembryanthemum crystallinum, phosphoenolpyruvate carboxylase is synthesized de novo in response to osmotic stress, as part of the switch from C3-photosynthesis to Crassulacean acid metabolism. To better understand the environmental signals involved in this pathway, we have investigated the effects of light on the induced expression of phosphoenolpyruvate carboxylase mRNA and protein in response to stress by 400 millimolar NaCl or 10 micromolar abscisic acid in hydroponically grown plants. When plants were grown in high-intensity fluorescent or incandescent light (850 microeinsteins per square meter per second), NaCl and abscisic acid induced approximately an eightfold accumulation of phosphoenolpyruvate carboxylase mRNA when compared to untreated controls. Levels of phosphoenolpyruvate carboxylase protein were high in these abscisic acid- and NaCl-treated plants, and detectable in the unstressed control. Growth in high-intensity incandescent (red) light resulted in approximately twofold higher levels of phosphoenolpyruvate carboxylase mRNA in the untreated plants when compared to control plants grown in high-intensity fluorescent light. In low light (300 microeinsteins per square meter per second fluorescent), only NaCl induced mRNA levels significantly above the untreated controls. Low light grown abscisic acid- and NaCl-treated plants contained a small amount of phosphoenolpyruvate carboxylase protein, whereas the (untreated) control plants did not contain detectable amounts of phosphoenolpyruvate carboxylase. Environmental stimuli, such as light and osmotic stress, exert a combined effect on gene expression in this facultative halophyte. ImagesFigure 1Figure 2 PMID:16668999

Comparison of Light Emitting Diodes (LED) and Fluorescent Light on Suppression of Pineal Melatonin in the Rat

NASA Technical Reports Server (NTRS)

Winget, Charles M.; Heeke, D. S.; Holley, D. C.; Mele, G.; Brainard, G. C.; Hanifin, J. P.; Rollag, M. D.; Savage, Paul D. (Technical Monitor)

1997-01-01

To validate a novel LED array for use in animal habitat lighting by comparing its effectiveness to cool-white fluorescent (CWF) lighting in suppressing pineal gland melatonin. Male Sprague-Dawley rats, 175-200 g, were maintained under control conditions for 2 weeks (food and water ad lib, 12L: 12D CWF, 18 uW/square cm). Dark adapted animals (animals before lights on) were exposed to 5 min of LED or CWF light of similar spectral power distribution. Two groups of rats (LED vs. CWF) were compared at 5 light intensities (100, 40, 1, 1.0, and 0. 1 lux). A control group was placed into the exposure apparatus but not exposed to light. After exposure, pineal glands were rapidly removed and assayed for melatonin by RIA. Results. The dark-exposed control groups matched with the 5 intensity groups (100, 40, 10, 1.0, and 0.1 lux) showed mean + SEM pineal melatonin values of 1167 +/- 136, 1569 +/- 126, 353 +/- 34, 650 +/- 124, and 464 +/- 85, pg/ml respectively. The corresponding CWF exposure data were 393 1 41, 365 +34, 257 +/- 13, 218 +/- 42, and 239 +/- 71 pg/ml, respectively. Corresponding LED exposure data were 439 +/- 25, 462 +/- 50, 231 +/- 6, 164 +/- 12, and 158 +/- 12 pg/ml, respectively. Rats exposed to both experimental light conditions at all illuminances studied showed significant melatonin suppression (p less than 0.01, ANOVA). In no case was the melatonin suppression induced by LED illuminance significantly different from the melatonin suppression elicited by the same intensity of CWF light. The results show that a novel LED light source can suppress pineal melatonin equal to that of a conventional CWF light source.

Evidence-Based Recommendations for Optimizing Light in Day-to-Day Spaceflight Operations

NASA Technical Reports Server (NTRS)

Whitmire, Alexandra; Leveton, Lauren; Barger, Laura; Clark, Toni; Bollweg, Laura; Ohnesorge, Kristine; Brainard, George

2015-01-01

NASA Behavioral Health and Performance Element (BHP) personnel have previously reported on efforts to transition evidence-based recommendations for a flexible lighting system on the International Space Station (ISS). Based on these recommendations, beginning in 2016 the ISS will replace the current fluorescent-based lights with an LED-based system to optimize visual performance, facilitate circadian alignment, promote sleep, and hasten schedule shifting. Additional efforts related to lighting countermeasures in spaceflight operations have also been underway. As an example, a recent BHP research study led by investigators at Harvard Medical School and Brigham and Women's Hospital, evaluated the acceptability, feasibility, and effectiveness of blue-enriched light exposure during exercise breaks for flight controllers working the overnight shift in the Mission Control Center (MCC) at NASA Johnson Space Center. This effort, along with published laboratory studies that have demonstrated the effectiveness of appropriately timed light for promoting alertness, served as an impetus for new light options, and educational protocols for flight controllers. In addition, a separate set of guidelines related to the light emitted from electronic devices, were provided to the Astronaut Office this past year. These guidelines were based on an assessment led by NASA's Lighting Environment Test Facility that included measuring the spectral power distribution, irradiance, and radiance of light emitted from ISS-grade laptops and I-Pads, as well as Android devices. Evaluations were conducted with and without the use of off-the-shelf screen filters as well as a software application that touts minimizing the short-wave length of the visible light spectrum. This presentation will focus on the transition for operations process related to lighting countermeasures in the MCC, as well as the evidence to support recommendations for optimal use of laptops, I-Pads, and Android devices during all phases of spaceflight operations.

A parallel bubble column system for the cultivation of phototrophic microorganisms.

PubMed

Havel, Jan; Franco-Lara, Ezequiel; Weuster-Botz, Dirk

2008-07-01

An incubator with up to 16 parallel bubble columns was equipped with artificial light sources assuring a light supply with a homogenous light spectrum directly above the bioreactors. Cylindrical light reflecting tubes were positioned around every single bubble column to avoid light scattering effects and to redirect the light from the top onto the cylindrical outer glass surface of each bubble column. The light reflecting tubes were equipped with light intensity filters to control the total light intensity for every single photo-bioreactor. Parallel cultivations of the unicellular obligate phototrophic cyanobacterium, Synechococcus PCC7942, were studied under different constant light intensities ranging from 20 to 102 microE m(-2)s(-1) at a constant humidified air flow rate supplemented with CO(2).

Effect of raceme-localized supplemental light on soybean reproductive abscission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, R.L.; Brun, W.A.; Brenner, M.L.

The percentage of soybean (Glycine max (L.) Merr.) reproductive structures that abscise is a potentially important yield factor. To better understand the involvement of light in the abscission of reproductive structures, a series of in vitro raceme-culture and growth-chamber experiments were conducted. In the in vitro raceme-culture experiments, racemes with four to six flowers at or past anthesis were excised from the soybean plant (genotype IX93-100), embedded in a complete nutrient, solid agar medium, and subjected to various light treatments. A series of three experiments indicated that the racemes contain a photoreceptor, possibly phytochrome, capable of regulating sucrose accumulation. Inmore » each of the growth chamber studies, supplemental light was supplied directly to individual soybean flowers via fiber optic light guides. The light source increased the photon flux to the flowers by 10-fold. The first growth chamber experiment showed that flowers receiving supplemental light were more intense sinks for /sup 14/C-sucrose than were controls (intensity value of 1.0 vs 0.4 x 10/sup -7/, intensity = (dps of flower/dps of raceme)/(kg dry wt of flower)). In a second study, 42% of flowers treated with supplemental light set pods, while only 26% of control flowers set pods. A third experiment showed that red supplemental light produced 55% fruit set, compared to 41% set for far-red light, and 35% for controls. These experiments indicate that both photoassimilate accumulation and abscission in young soybean reproductive structures may be regulated by light quality.« less

Effects of continuous white light and 12h white-12h blue light-cycles on the expression of clock genes in diencephalon, liver, and skeletal muscle in chicks.

PubMed

Honda, Kazuhisa; Kondo, Makoto; Hiramoto, Daichi; Saneyasu, Takaoki; Kamisoyama, Hiroshi

2017-05-01

The core circadian clock mechanism relies on a feedback loop comprised of clock genes, such as the brain and muscle Arnt-like 1 (Bmal1), chriptochrome 1 (Cry1), and period 3 (Per3). Exposure to the light-dark cycle synchronizes the master circadian clock in the brain, and which then synchronizes circadian clocks in peripheral tissues. Birds have long been used as a model for the investigation of circadian rhythm in human neurobiology. In the present study, we examined the effects of continuous light and the combination of white and blue light on the expression of clock genes (Bmal1, Cry1, and Per3) in the central and peripheral tissues in chicks. Seventy two day-old male chicks were weighed, allocated to three groups and maintained under three light schedules: 12h white light-12h dark-cycles group (control); 24h white light group (WW group); 12h white light-12h blue light-cycles group (WB group). The mRNA levels of clock genes in the diencephalon were significantly different between the control and WW groups. On the other hand, the alteration in the mRNA levels of clock genes was similar between the control and WB groups. Similar phenomena were observed in the liver and skeletal muscle (biceps femoris). These results suggest that 12h white-12h blue light-cycles did not disrupt the circadian rhythm of clock gene expression in chicks. Copyright © 2017 Elsevier Inc. All rights reserved.

Visible-Light-Driven BiOI-Based Janus Micromotor in Pure Water.

PubMed

Dong, Renfeng; Hu, Yan; Wu, Yefei; Gao, Wei; Ren, Biye; Wang, Qinglong; Cai, Yuepeng

2017-02-08

Light-driven synthetic micro-/nanomotors have attracted considerable attention due to their potential applications and unique performances such as remote motion control and adjustable velocity. Utilizing harmless and renewable visible light to supply energy for micro-/nanomotors in water represents a great challenge. In view of the outstanding photocatalytic performance of bismuth oxyiodide (BiOI), visible-light-driven BiOI-based Janus micromotors have been developed, which can be activated by a broad spectrum of light, including blue and green light. Such BiOI-based Janus micromotors can be propelled by photocatalytic reactions in pure water under environmentally friendly visible light without the addition of any other chemical fuels. The remote control of photocatalytic propulsion by modulating the power of visible light is characterized by velocity and mean-square displacement analysis of optical video recordings. In addition, the self-electrophoresis mechanism has been confirmed for such visible-light-driven BiOI-based Janus micromotors by demonstrating the effects of various coated layers (e.g., Al 2 O 3 , Pt, and Au) on the velocity of motors. The successful demonstration of visible-light-driven Janus micromotors holds a great promise for future biomedical and environmental applications.

Doehlert experimental design applied to optimization of light emitting textile structures

NASA Astrophysics Data System (ADS)

Oguz, Yesim; Cochrane, Cedric; Koncar, Vladan; Mordon, Serge R.

2016-07-01

A light emitting fabric (LEF) has been developed for photodynamic therapy (PDT) for the treatment of dermatologic diseases such as Actinic Keratosis (AK). A successful PDT requires homogenous and reproducible light with controlled power and wavelength on the treated skin area. Due to the shape of the human body, traditional PDT with external light sources is unable to deliver homogenous light everywhere on the skin (head vertex, hand, etc.). For better light delivery homogeneity, plastic optical fibers (POFs) have been woven in textile in order to emit laterally the injected light. The previous studies confirmed that the light power could be locally controlled by modifying the radius of POF macro-bendings within the textile structure. The objective of this study is to optimize the distribution of macro-bendings over the LEF surface in order to increase the light intensity (mW/cm2), and to guarantee the best possible light deliver homogeneity over the LEF which are often contradictory. Fifteen experiments have been carried out with Doehlert experimental design involving Response Surface Methodology (RSM). The proposed models are fitted to the experimental data to enable the optimal set up of the warp yarns tensions.

Monolithic LED arrays, next generation smart lighting sources

NASA Astrophysics Data System (ADS)

Lagrange, Alexandre; Bono, Hubert; Templier, François

2016-03-01

LED have become the main light sources of the future as they open the path for intelligent use of light in time, intensity and color. In many usages, strong energy economy is done by adjusting these properties. The smart lighting has three dimensions, energy efficiency brought by GaN blue emitting LEDs, integration of electronics, sensors, microprocessors in the lighting system and development of new functionalities and services provided by the light. Monolithic LED arrays allow two major innovations, the spatial control of light emission and the adjustment of the electrical properties of the source.

Self-control of traffic lights and vehicle flows in urban road networks

NASA Astrophysics Data System (ADS)

Lämmer, Stefan; Helbing, Dirk

2008-04-01

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

Budget-Minded Renovation Lights Up Students' Learning.

ERIC Educational Resources Information Center

McDaniel, Craig

1998-01-01

Provides considerations for educational facility lighting designs that support student learning while controlling costs. Lighting design decision factors include the types of classroom activities involved, the importance of properly using artificial and indirect lighting, the importance of color rendering, the positioning of windows and skylights,…

Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

PubMed

Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

2015-04-01

Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of night illumination, red and infrared light, on locomotor activity, behaviour and melatonin of Senegalese sole (Solea senegalensis) broodstock.

PubMed

Carazo, I; Norambuena, F; Oliveira, C; Sánchez-Vázquez, F J; Duncan, N J

2013-06-13

The present study aimed to determine a non-invasive nocturnal lighting system for the behavioural observation of a highly light sensitive species, Senegalese sole (Solea senegalensis). Locomotor activity, four types of behaviour and plasma melatonin were analysed in groups of 12 adult Senegalese sole (Solea senegalensis) reared in captivity and held under four night illumination treatments: total darkness (control), high 50lux intensity red light (group RH), low 5lux intensity red light (group RL) and infrared light (group IR). All groups experienced the same conditions during the day (lights on from 07:00 to 19:00) with white lighting of 125lux. Clarity of video images taken at night for the observation of fish behaviour were ranked as follows: group RH>RL>IR>control. All treatments presented a daily rhythm in locomotor activity with high activity from 14:00 to 18:00 and low activity from 21:00 to 12:00. The sole exposed to the high intensity red light at night appeared to be disturbed as during the low nocturnal locomotor activity period group RH presented higher activity and significantly higher nocturnal behaviour related to escape or fear than was observed in the other groups. The groups control, RL and IR exhibited similar levels of nocturnal locomotor activity and nocturnal behaviour related to escape or fear. Plasma melatonin, at mid-dark was not significantly different between the control and groups RL and IR, while melatonin was significantly lower in group RH compared to the control. The authors recommended low intensity red night illumination for the non-invasive study of nocturnal behaviour of Senegalese sole adults. Copyright © 2013 Elsevier Inc. All rights reserved.

Long-term effects of chronic light pollution on seasonal functions of European blackbirds (Turdus merula).

PubMed

Dominoni, Davide M; Quetting, Michael; Partecke, Jesko

2013-01-01

Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems.

Effect of ambient light and age-related macular degeneration on precision walking.

PubMed

Alexander, M Scott; Lajoie, Kim; Neima, David R; Strath, Robert A; Robinovitch, Stephen N; Marigold, Daniel S

2014-08-01

To determine how age-related macular degeneration (AMD) and changes in ambient light affect the control of foot placement while walking. Ten older adults with AMD and 11 normal-sighted controls performed a precision walking task under normal (∼600 lx), dim (∼0.7 lx), and after a sudden reduction (∼600 to 0.7 lx) of light. The precision walking task involved subjects walking and stepping to the center of a series of irregularly spaced, low-contrast targets. Habitual visual acuity and contrast sensitivity and visual field function were also assessed. There were no differences between groups when performing the walking task in normal light (p > 0.05). In reduced lighting, older adults with AMD were less accurate and more variable when stepping across the targets compared to controls (p < 0.05). A sudden reduction of light proved the most challenging for this population. In the AMD group, contrast sensitivity and visual acuity were not significantly correlated with walking performance. Visual field thresholds in the AMD group were only associated with greater foot placement error and variability in the dim light walking condition (r = -0.69 to -0.87, p < 0.05). While walking performance is similar between groups in normal light, poor ambient lighting results in decreased foot placement accuracy in older adults with AMD. Improper foot placement while walking can lead to a fall and possible injury. Thus, to improve the mobility of those with AMD, strategies to enhance the environment in reduced lighting situations are necessary.

Hyperspectral Image-Based Night-Time Vehicle Light Detection Using Spectral Normalization and Distance Mapper for Intelligent Headlight Control.

PubMed

Kim, Heekang; Kwon, Soon; Kim, Sungho

2016-07-08

This paper proposes a vehicle light detection method using a hyperspectral camera instead of a Charge-Coupled Device (CCD) or Complementary metal-Oxide-Semiconductor (CMOS) camera for adaptive car headlamp control. To apply Intelligent Headlight Control (IHC), the vehicle headlights need to be detected. Headlights are comprised from a variety of lighting sources, such as Light Emitting Diodes (LEDs), High-intensity discharge (HID), and halogen lamps. In addition, rear lamps are made of LED and halogen lamp. This paper refers to the recent research in IHC. Some problems exist in the detection of headlights, such as erroneous detection of street lights or sign lights and the reflection plate of ego-car from CCD or CMOS images. To solve these problems, this study uses hyperspectral images because they have hundreds of bands and provide more information than a CCD or CMOS camera. Recent methods to detect headlights used the Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM), and Euclidean Distance Mapper (EDM). The experimental results highlight the feasibility of the proposed method in three types of lights (LED, HID, and halogen).

In situ calibration of a light source in a sensor device

DOEpatents

Okandan, Murat; Serkland, Darwin k.; Merchant, Bion J.

2015-12-29

A sensor device is described herein, wherein the sensor device includes an optical measurement system, such as an interferometer. The sensor device further includes a low-power light source that is configured to emit an optical signal having a constant wavelength, wherein accuracy of a measurement output by the sensor device is dependent upon the optical signal having the constant wavelength. At least a portion of the optical signal is directed to a vapor cell, the vapor cell including an atomic species that absorbs light having the constant wavelength. A photodetector captures light that exits the vapor cell, and generates an electrical signal that is indicative of intensity of the light that exits the vapor cell. A control circuit controls operation of the light source based upon the electrical signal, such that the light source emits the optical signal with the constant wavelength.

A superior architecture of brightness enhancement for display backlighting

NASA Astrophysics Data System (ADS)

Dross, Oliver; Parkyn, William A.; Chaves, Julio; Falicoff, Waqidi; Miñano, Juan Carlos; Benitez, Pablo; Alvarez, Roberto

2006-08-01

Brightness enhancement of backlighting for displays is typically achieved via crossed micro prismatic films that are introduced between a backlight unit and a transmissive (LCD) display. Prismatic films let pass light only into a restricted angular range, while, in conjunction with other reflective elements below the backlight, all other light is recycled within the backlight unit, thereby increasing the backlight luminance. This design offers no free parameters to influence the resulting light distribution and suffers from insufficient stray light control. A novel strategy of light recycling is introduced, using a microlens array in conjunction with a hole array in a reflective surface, that can provide higher luminance, superior stray light control, and can be designed to meet almost any desired emission pattern. Similar strategies can be applied to mix light from different colored LEDs being mounted upside down to shine into a backlight unit.

Light-regulated leaf expansion in two Populus species: dependence on developmentally controlled ion transport.

PubMed

Stiles, Kari A; Van Volkenburgh, Elizabeth

2002-07-01

Leaf growth responses to light have been compared in two species of Populus, P. deltoides and P. trichocarpa. These species differ markedly in morphology, anatomy, and dependence on light during leaf expansion. Light stimulates the growth rate and acidification of cell walls in P. trichocarpa but not in P. deltoides, whereas leaves of P. deltoides maintain growth in the dark. Light-induced growth is promoted in P. deltoides when cells are provided 50-100 mM KCl. In both species, light initially depolarizes, then hyperpolarizes mesophyll plasma membranes. However, in the dark, the resting E(m) of mesophyll cells in P. deltoides, but not in P. trichocarpa, is relatively insensitive to decade changes in external [K+]. Results suggest that light-stimulated leaf growth depends on developmentally regulated cellular mechanisms controlling ion fluxes across the plasma membrane. These developmental differences underlie species-level differences in growth and physiological responses to the photoenvironment.

AUTOMATIC LIGHT CONTROL

DOEpatents

Artzt, M.

1957-08-27

A control system for a projection kinescope used in a facsimile scanning system and, in particular, meams for maintaining substantially constant the light emanating from the flying spot on the face of the kinescope are described. In general, the invention provides a feeler member disposed in such a position with respect to a projecting lens as to intercept a portion of the light striking the lens. Suitable circuitry in conjunction with a photomultiplier tube provides a signal proportional to the light intensity of the flying spot. The grid bias on the kinescope is controlled by this signal to maintain the intensity of the spot substantially constant.

Effects of periodic photoinhibitory light exposure on physiology and productivity of Arabidopsis plants grown under low light.

PubMed

Tian, Yonglan; Sacharz, Joanna; Ware, Maxwell A; Zhang, Huayong; Ruban, Alexander V

2017-07-10

This work examined the long-term effects of periodic high light stress on photosynthesis, morphology, and productivity of low-light-acclimated Arabidopsis plants. Significant photoinhibition of Arabidopsis seedlings grown under low light (100 μmol photons m-2 s-1) was observed at the beginning of the high light treatment (three times a day for 30 min at 1800 μmol photons m-2 s-1). However, after 2 weeks of treatment, similar photosynthesis yields (Fv/Fm) to those of control plants were attained. The daily levels of photochemical quenching measured in the dark (qPd) indicated that the plants recovered from photoinhibition within several hours once transferred back to low light conditions, with complete recovery being achieved overnight. Acclimation to high light stress resulted in the modification of the number, structure, and position of chloroplasts, and an increase in the average chlorophyll a/b ratio. During ontogenesis, high-light-exposed plants had lower total leaf areas but higher above-ground biomass. This was attributed to the consumption of starch for stem and seed production. Moreover, periodic high light exposure brought forward the reproductive phase and resulted in higher seed yields compared with control plants grown under low light. The responses to periodic high light exposure of mature Arabidopsis plants were similar to those of seedlings but had higher light tolerance. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Daily light integral and day light quality: Potentials and pitfalls of nighttime UV treatments on cucumber powdery mildew.

PubMed

Suthaparan, Aruppillai; Solhaug, Knut Asbjørn; Stensvand, Arne; Gislerød, Hans Ragnar

2017-10-01

Nighttime ultraviolet (UV) radiation, if applied properly, has a significant potential for management of powdery mildews in many crop species. In this study, the role of growth light duration, irradiance, a combination of both (daily light integral) and light spectral quality (blue or red) on the efficacy of UV treatments against powdery mildew caused by Podosphaera xanthii and the growth performance of cucumber plants was studied in growth chambers. Increasing daily light integral provided by high-pressure sodium lamps (HPS) decreased efficacy of nighttime UV treatments against P. xanthii, but it increased plant growth. Furthermore, the efficacy of nighttime UV decreased when day length was increased from 16 to 20h at a constant daily light integral. The efficacy of nighttime UV increased if red light was applied after UV treatment, showing the possibility of day length extension without reducing the effect of UV. Increasing the dose of blue light during daytime reduced the efficacy of nighttime UV in controlling the disease, whereas blue deficient growth light (<6% of blue) caused UV mediated curling of young leaves. Furthermore, application of blue light after nighttime UV reduced its disease control efficacy. This showed the importance of maintaining a minimum of blue light in the growth light before nighttime UV treatment. Findings from this study showed that optimization of nighttime UV for management of powdery mildew is dependent on the spectral composition of the photosynthetically active radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals - A randomized controlled trial.

PubMed

Knaier, Raphael; Klenk, Christopher; Königstein, Karsten; Hinrichs, Timo; Rossmeissl, Anja; Infanger, Denis; Cajochen, Christian; Schmidt-Trucksäss, Arno

2018-04-01

Overweight is a worldwide increasing public health issue. Physical exercise is a useful countermeasure. Overweight individuals choose rather low exercise intensities, but especially high exercise intensities lead to higher energy expenditure and show beneficial health effects compared to lower exercise intensities. However, especially in the morning higher exercise intensities are likely to be avoided due to higher subjective effort. Bright light exposure has shown to increase maximum performance. The aim of this study was to investigate if bright light exposure can also increase self-chosen exercise intensity. We hypothesized that morning bright light exposure increases self-chosen exercise intensity of subsequent exercise through increased mood and reduced sleepiness in overweight individuals. In this randomized controlled single-blind parallel group design, 26 overweight individuals (11 males, 15 females; age 25 ± 5.7 years; body mass index 28.9 ± 2.1 kg/m 2 ) underwent three measurement appointments. On the first appointment, subjects performed a cardiopulmonary exercise test to measure maximum oxygen uptake (VO2max). Two days later a 30-min exercise session with self-chosen exercise intensity was performed for familiarization. Then subjects were randomly allocated to bright light (~4400 lx) or a control light (~230 lx) condition. Three to seven days later, subjects were exposed to light for 30 min starting at 8:00 am, immediately followed by a 30-min exercise session with persisting light exposure. Multidimensional mood questionnaires were filled out before and after the light exposure and after the exercise session. The primary outcome was the mean power output during the exercise session and the secondary outcome the rating on the three domains (i.e. good-bad; awake-tired; calm-nervous) of the multidimensional mood questionnaire. Mean power output during the exercise session was 92 ± 19 W in bright light and 80 ± 37 W in control light, respectively. In the multivariate analysis adjusted for VO2max, the mean power output during the exercise session was 8.5 W higher (95% confidence interval -12.7, 29.7; p = 0.416) for participants in bright light compared to control light. There were no significant differences between the groups for any of the three domains of the questionnaire at any time point. This is in contrast to longer lasting intervention studies that show positive influences on mood and suggests that bright light therapy requires repetitive sessions to improve mood in overweight individuals. In conclusion bright light exposure does not acutely increase self-chosen exercise intensity or improve mood in a 30-min exercise session starting at 08:30. However, regarding the fact that overweight is a worldwide and rapidly increasing public health issue even small increases in exercise intensity may be relevant. The trend toward superiority of bright light over control light implicates that further studies may be conducted in a larger scale. VO2max: maximum oxygen uptake; 95% CI: 95% confidence interval; SD: standard deviation.

40 CFR 86.1401 - Scope; applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Gasoline-Fueled Otto-Cycle Light-Duty Vehicles and New Gasoline-Fueled Otto-Cycle Light-Duty... procedures for gasoline-fueled Otto-cycle light-duty vehicles, and for gasoline-fueled Otto-cycle light-duty...

47 CFR 17.56 - Maintenance of lighting equipment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... § 17.56 Maintenance of lighting equipment. (a) Replacing or repairing of lights, automatic indicators or automatic control or alarm systems shall be accomplished as soon as practicable. (b) The flash tubes in a high intensity obstruction lighting system shall be replaced whenever the peak effective...

Transmitting and reflecting diffuser. [for ultraviolet light

NASA Technical Reports Server (NTRS)

Keafer, L. S., Jr.; Burcher, E. E.; Kopia, L. P. (Inventor)

1973-01-01

A near-Lambertian diffuser is described which transmits and reflects ultraviolet light. An ultraviolet grade fused silica substrate is coated with vaporized fuse silica. The coating thickness is controlled, one thickness causing ultraviolet light to diffuse and another thickness causing ultraviolet light to reflect a near Lambertian pattern.

Advanced Lighting Controls for Reducing Energy use and Cost in DoD Installations

DTIC Science & Technology

2013-05-01

OccuSwitch Wireless is a room-based lighting control system employing dimmable light sources, occupancy and daylight sensors , wireless interconnection...combination of wireless and wired control solution for building-wide networked system that maximizes the use of daylight while improving visual...architecture of Hybrid ILDC. Architecture: The system features wireless connectivity among sensors and actuators within a zone and exploits wired

Experimental light scattering by positionally-controlled small particles — Implications for Planetary Science

NASA Astrophysics Data System (ADS)

Gritsevich, M.; Penttilä, A.; Maconi, G.; Kassamakov, I.; Martikainen, J.; Markkanen, J.; Vaisanen, T.; Helander, P.; Puranen, T.; Salmi, A.; Hæggström, E.; Muinonen, K.

2017-12-01

Electromagnetic scattering is a fundamental physical process that allows inferring characteristics of an object studied remotely. This possibility is enhanced by obtaining the light-scattering response at multiple wavelengths and viewing geometries, i.e., by considering a wider range of the phase angle (the angle between the incident light and the light reflected from the object) in the experiment. Within the ERC Advanced Grant project SAEMPL (http://cordis.europa.eu/project/rcn/107666_en.html) we have assembled an interdisciplinary group of scientists to develop a fully automated, 3D scatterometer that can measure scattered light at different wavelengths from small particulate samples. The setup comprises: (a) the PXI Express platform to synchronously record data from several photomultiplier tubes (PMTs); (b) a motorized rotation stage to precisely control the azimuthal angle of the PMTs around 360°; and (c) a versatile light source, whose wavelength, polarization, intensity, and beam shape can be precisely controlled. An acoustic levitator is used to hold the sample without touching it. The device is the first of its kind, since it measures controlled spectral angular scattering including all polarization effects, for an arbitrary object in the µm-cm size scale. It permits a nondestructive, disturbance-free measurement with control of the orientation and location of the scattering object. To demonstrate our approach we performed detailed measurements of light scattered by a Chelyabinsk LL5 chondrite particle, derived from the light-colored lithology sample of the meteorite. These measurements are cross-validated against the modeled light-scattering characteristics of the sample, i.e., the intensity and the degree of linear polarization of the reflected light, calculated with state-of-the-art electromagnetic techniques (see Muinonen et al., this meeting). We demonstrate a unique non-destructive approach to derive the optical properties of small grain samples which facilitates research on highly valuable planetary materials, such as samples returned from space missions or rare meteorites.

The utilization of nonthermal blue (405-425 nm) and near infrared (850-890 nm) light in aesthetic dermatology and surgery-a multicenter study.

PubMed

Lask, Gary; Fournier, Nathalie; Trelles, Mario; Elman, Monica; Scheflan, Michael; Slatkine, Michael; Naimark, Jenny; Harth, Yoram

2005-12-01

A major cause of skin aging is a chronic micro-inflammation triggered by UV radiation and external pollutants. It has been demonstrated that blue light diminishes inflammatory conditions and near infrared light enhances circulation. To assess the effectiveness of a non thermal dual wavelength -- blue (405 - 420 nm) and near infrared (850 - 900 nm) -- light source in skin rejuvenation, in the reduction of the duration of post skin resurfacing erythema and in the acceleration of healing of post surgical conditions (face lift and breast augmentation). We have utilized a non contact, hand free dual wavelength light source (iClearXL and Clear100XL, Curelight Ltd) to treat over 60 patients and perform three controlled studies in four centers. Follow up duration was three months. Control group for photo-rejuvenation consisted of patients treated with Glycolic peeling and daily appliance of vitamin C Control group for post skin resurfacing erythema duration consisted of patients untreated by the light source and control group for post surgical healing consisted of patients untreated by the light source or treated by the light source on one side only. Post skin resurfacing erythema duration is reduced by 90%. The healing of post surgical conditions is substantially accelerated and discomfort is reduced. The anti aging effect of the light source includes: reduction of pore size in 90% of patients with stable results at three months follow up, enhanced skin radiance in 90% of patients with stable results at three months follow up and smoothing of fine wrinkles in 45% of patients with stable results at three months follow up. The control group showed poor results which were stable for a duration of less than one month. A non thermal, non contact / hand free light source emitting at 405-420 nm and 850-900 nm considerably enhances aesthetic and surgical aesthetic procedures without consuming user time.

Modelling the effect of diffuse light on canopy photosynthesis in controlled environments

NASA Technical Reports Server (NTRS)

Cavazzoni, James; Volk, Tyler; Tubiello, Francesco; Monje, Oscar; Janes, H. W. (Principal Investigator)

2002-01-01

A layered canopy model was used to analyze the effects of diffuse light on canopy gross photosynthesis in controlled environment plant growth chambers, where, in contrast to the field, highly diffuse light can occur at high irradiance. The model suggests that high diffuse light fractions (approximately 0.7) and irradiance (1400 micromoles m-2 s-1) may enhance crop life-cycle canopy gross photosynthesis for hydroponic wheat by about 20% compared to direct light at the same irradiance. Our simulations suggest that high accuracy is not needed in specifying diffuse light fractions in chambers between approximately 0.7 and 1, because simulated photosynthesis for closed canopies plateau in this range. We also examined the effect of leaf angle distribution on canopy photosynthesis under growth chamber conditions, as these distributions determine canopy extinction coefficients for direct and diffuse light. We show that the spherical leaf angle distribution is not suitable for modeling photosynthesis of planophile canopies (e.g., soybean and peanut) in growth chambers. Also, the absorption of the light reflected from the surface below the canopy should generally be included in model simulations, as the corresponding albedo values in the photosynthetically active range may be quite high in growth chambers (e.g., approximately 0.5). In addition to the modeling implications, our results suggest that diffuse light conditions should be considered when drawing conclusions from experiments in controlled environments.

Light scattering and light transmittance of cadaver eye-explanted intraocular lenses of different materials.

PubMed

Morris, Caleb; Werner, Liliana; Barra, Daniel; Liu, Erica; Stallings, Shannon; Floyd, Anne

2014-01-01

To evaluate light scattering and light transmittance in cadaver eye-explanted intraocular lenses (IOLs) manufactured from different materials. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Forty-nine pseudophakic cadaver eyes were selected according to IOL material/type and implantation duration, and the IOLs were explanted. Hydrophobic acrylic, hydrophilic acrylic, poly(methyl methacrylate) (PMMA), and silicone IOLs were included. Gross and light microscopy was performed for all IOLs. Light scattering was measured with an EAS 1000 Scheimpflug camera, and light transmittance was assessed using a Lambda 35 UV/Vis spectrophotometer (single-beam configuration with an RSA PE-20 integrating sphere). Analyses were performed at room temperature in the hydrated state and compared with analyses of controls. The highest levels of surface light scattering were measured for 3-piece hydrophobic acrylic, which was also the IOL type with the longest implantation duration among the Acrysof hydrophobic acrylic IOLs. Hydrophilic acrylic, PMMA, and silicone IOLs exhibited relatively low light-scattering levels. The lowest light-scattering levels were observed with PMMA IOLs (1-piece looped and 3-piece) and plate silicone IOLs, which represent the IOL types with the longest implantation duration in this series. Light transmittance values measured for all IOL types appeared to be similar to the values of the corresponding control IOLs. The phenomenon of surface light scattering (nanoglistenings) is more particularly related to hydrophobic acrylic IOLs and increases with implantation time. No significant effect of surface light scattering on IOL light transmittance was found. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Ocular forward light scattering and corneal backward light scattering in patients with dry eye.

PubMed

Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Asonuma, Sanae; Mitamura, Hayato; Oie, Yoshinori; Soma, Takeshi; Tsujikawa, Motokazu; Kawasaki, Satoshi; Nishida, Kohji

2014-09-18

To evaluate ocular forward light scattering and corneal backward light scattering in patients with dry eye. Thirty-five eyes in 35 patients with dry eye and 20 eyes of 20 healthy control subjects were enrolled. The 35 dry eyes were classified into two groups according to whether superficial punctate keratopathy in the central 6-mm corneal zone (cSPK) was present or not. Ocular forward light scattering was quantified with a straylight meter. Corneal backward light scattering from the anterior, middle, and posterior corneal parts was assessed with a corneal densitometry program using the Scheimpflug imaging system. Both dry eye groups had significantly higher intraocular forward light scattering than the control group (both P<0.05). The dry eye group with cSPK had significantly higher values in anterior and total corneal backward light scattering than the other two groups. Moderate positive correlations were observed between the cSPK score and corneal backward light scattering from the anterior cornea (R=0.60, P<0.001) and corneal backward light scattering from the total cornea (R=0.54, P<0.001); however, no correlation was found between cSPK score and ocular forward light scattering (R=0.01, P=0.932). Ocular forward light scattering and corneal backward light scattering from the anterior cornea were greater in dry eyes than in normal eyes. Increased corneal backward light scattering in dry eye at least partially results from cSPK overlying the optical zone. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Chapter 2: Commercial and Industrial Lighting Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurnik, Charles W; Gowans, Dakers; Telarico, Chad

The Commercial and Industrial Lighting Evaluation Protocol (the protocol) describes methods to account for gross energy savings resulting from the programmatic installation of efficient lighting equipment in large populations of commercial, industrial, and other nonresidential facilities. This protocol does not address savings resulting from changes in codes and standards, or from education and training activities. A separate Uniform Methods Project (UMP) protocol, Chapter 3: Commercial and Industrial Lighting Controls Evaluation Protocol, addresses methods for evaluating savings resulting from lighting control measures such as adding time clocks, tuning energy management system commands, and adding occupancy sensors.

Active Beam Shaping System and Method Using Sequential Deformable Mirrors

NASA Technical Reports Server (NTRS)

Pueyo, Laurent A. (Inventor); Norman, Colin A. (Inventor)

2015-01-01

An active optical beam shaping system includes a first deformable mirror arranged to at least partially intercept an entrance beam of light and to provide a first reflected beam of light, a second deformable mirror arranged to at least partially intercept the first reflected beam of light from the first deformable mirror and to provide a second reflected beam of light, and a signal processing and control system configured to communicate with the first and second deformable mirrors. The first deformable mirror, the second deformable mirror and the signal processing and control system together provide a large amplitude light modulation range to provide an actively shaped optical beam.

Blue light (470 nm) effectively inhibits bacterial and fungal growth.

PubMed

De Lucca, A J; Carter-Wientjes, C; Williams, K A; Bhatnagar, D

2012-12-01

Blue light (470 nm) LED antimicrobial properties were studied alone against bacteria and with or without the food grade photosensitizer, erythrosine (ERY) against filamentous fungi. Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA) or Pseudomonas aeruginosa (PA) aliquots were exposed on nutrient agar plates to Array 1 (AR1, 0·2 mW cm(-2)) or Array 2 (AR2, 80 mW cm(-2)), which emitted impure or pure blue light (0-300 J cm(-2)), respectively. Inoculated control (room light only) plates were incubated (48 h) and colonies enumerated. The antifungal properties of blue light combined with ERY (11·4 and 22·8 μmol l(-1)) on Penicillium digitatum (PD) and Fusarium graminearum (FG) conidia were determined. Conidial controls consisted of: no light, room light-treated conidia and ERY plus room light. Light-treated (ERY + blue light) conidial samples were exposed only to AR2 (0-100 J cm(-2)), aliquots spread on potato dextrose agar plates, incubated (48 h, 30°C) and colonies counted. Blue light alone significantly reduced bacterial and FG viability. Combined with ERY, it significantly reduced PD viability. Blue light is lethal to bacteria and filamentous fungi although effectiveness is dependent on light purity, energy levels and microbial genus. Light from two arrays of different blue LEDs significantly reduced bacterial (Leuconostoc mesenteroides, Bacillus atrophaeus and Pseudomonas aeruginosa) viabilities. Significant in vitro viability loss was observed for the filamentous fungi, Penicillium digitatum and Fusarium graminearum when exposed to pure blue light only plus a photosensitizer. F. graminearum viability was significantly reduced by blue light alone. Results suggest that (i) the amount of significant loss in bacterial viability observed for blue light that is pure or with traces of other wavelengths is genus dependent and (ii) depending on fungal genera, pure blue light is fungicidal with or without a photosensitizer. © 2012 The Society for Applied Microbiology.

Effect of disposable infection control barriers on light output from dental curing lights.

PubMed

Scott, Barbara A; Felix, Corey A; Price, Richard B T

2004-02-01

To prevent contamination of the light guide on a dental curing light, barriers such as disposable plastic wrap or covers may be used. This study compared the effect of 3 disposable barriers on the spectral output and power density from a curing light. The hypothesis was that none of the barriers would have a significant clinical effect on the spectral output or the power density from the curing light. Three disposable barriers were tested against a control (no barrier). The spectra and power from the curing light were measured with a spectrometer attached to an integrating sphere. The measurements were repeated on 10 separate occasions in a random sequence for each barrier. Analysis of variance (ANOVA) followed by Fisher's protected least significant difference test showed that the power density was significantly less than control (by 2.4% to 6.1%) when 2 commercially available disposable barriers were used (p < 0.05). There was no significant difference in the power density when general-purpose plastic wrap was used (p > 0.05). The effect of each of the barriers on the power output was small and probably clinically insignificant. ANOVA comparisons of mean peak wavelength values indicated that none of the barriers produced a significant shift in the spectral output relative to the control ( p > 0.05). Two of the 3 disposable barriers produced a significant reduction in power density from the curing light. This drop in power was small and would probably not adversely affect the curing of composite resin. None of the barriers acted as light filters.

Enlightening Butterfly Conservation Efforts: The Importance of Natural Lighting for Butterfly Behavioral Ecology and Conservation

PubMed Central

2018-01-01

Light is arguably the most important abiotic factor for living organisms. Organisms evolved under specific lighting conditions and their behavior, physiology, and ecology are inexorably linked to light. Understanding light effects on biology could not be more important as present anthropogenic effects are greatly changing the light environments in which animals exist. The two biggest anthropogenic contributors changing light environments are: (1) anthropogenic lighting at night (i.e., light pollution); and (2) deforestation and the built environment. I highlight light importance for butterfly behavior, physiology, and ecology and stress the importance of including light as a conservation factor for conserving butterfly biodiversity. This review focuses on four parts: (1) Introducing the nature and extent of light. (2) Visual and non-visual light reception in butterflies. (3) Implications of unnatural lighting for butterflies across several different behavioral and ecological contexts. (4). Future directions for quantifying the threat of unnatural lighting on butterflies and simple approaches to mitigate unnatural light impacts on butterflies. I urge future research to include light as a factor and end with the hopeful thought that controlling many unnatural light conditions is simply done by flipping a switch. PMID:29439549

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

PubMed Central

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

14 CFR 23.812 - Emergency lighting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... light that illuminates in the cockpit when power is on in the airplane and the emergency lighting... station and be provided with automatic activation. The cockpit control device must have “on,” “off,” and... “armed” or “on” positions. (e) The cockpit control device must have provisions to allow the emergency...

Design of a Programmable Star Tracker-Based Reference System for a Simulated Spacecraft

DTIC Science & Technology

2014-03-27

This reduces the overall light intensity hitting the sensor, as indicated by the darker color. However, the red and green circles are also forming...may be beneficial on SimSat since we can control the light output depending on the source chosen. It is possible to sacrifice some star light intensity ...could be done to improve accuracy based on what could be controlled and changed easily. 3.2.3.1 Focal Length. The optics portion of the light collection

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

PubMed

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 important performance advantage justifying further studies. In conclusion, we report novel evidence that evening light exposure, which strongly impacts the human circadian timing system, enables elite athletes to better maintain performance across a 12-min cycling time trial.

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

PubMed Central

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 important performance advantage justifying further studies. In conclusion, we report novel evidence that evening light exposure, which strongly impacts the human circadian timing system, enables elite athletes to better maintain performance across a 12-min cycling time trial. PMID:28507521

Human phase response curve to intermittent blue light using a commercially available device

PubMed Central

Revell, Victoria L; Molina, Thomas A; Eastman, Charmane I

2012-01-01

Light shifts the timing of the circadian clock according to a phase response curve (PRC). To date, all human light PRCs have been to long durations of bright white light. However, melanopsin, the primary photopigment for the circadian system, is most sensitive to short wavelength blue light. Therefore, to optimise light treatment it is important to generate a blue light PRC. We used a small, commercially available blue LED light box, screen size 11.2 × 6.6 cm at ∼50 cm, ∼200 μW cm−2, ∼185 lux. Subjects participated in two 5 day laboratory sessions 1 week apart. Each session consisted of circadian phase assessments to obtain melatonin profiles before and after 3 days of free-running through an ultradian light–dark cycle (2.5 h wake in dim light, 1.5 h sleep in the dark), forced desynchrony protocol. During one session subjects received intermittent blue light (three 30 min pulses over 2 h) once a day for the 3 days of free-running, and in the other session (control) they remained in dim room light, counterbalanced. The time of blue light was varied among subjects to cover the entire 24 h day. For each individual, the phase shift to blue light was corrected for the free-run determined during the control session. The blue light PRC had a broad advance region starting in the morning and extending through the afternoon. The delay region started a few hours before bedtime and extended through the night. This is the first PRC to be constructed to blue light and to a stimulus that could be used in the real world. PMID:22753544

Human phase response curve to intermittent blue light using a commercially available device.

PubMed

Revell, Victoria L; Molina, Thomas A; Eastman, Charmane I

2012-10-01

Light shifts the timing of the circadian clock according to a phase response curve (PRC). To date, all human light PRCs have been to long durations of bright white light. However, melanopsin, the primary photopigment for the circadian system, is most sensitive to short wavelength blue light. Therefore, to optimise light treatment it is important to generate a blue light PRC.We used a small, commercially available blue LED light box, screen size 11.2 × 6.6 cm at ∼50 cm, ∼200 μW cm(−2), ∼185 lux. Subjects participated in two 5 day laboratory sessions 1 week apart. Each session consisted of circadian phase assessments to obtain melatonin profiles before and after 3 days of free-running through an ultradian light–dark cycle (2.5 h wake in dim light, 1.5 h sleep in the dark), forced desynchrony protocol. During one session subjects received intermittent blue light (three 30 min pulses over 2 h) once a day for the 3 days of free-running, and in the other session (control) they remained in dim room light, counterbalanced. The time of blue light was varied among subjects to cover the entire 24 h day. For each individual, the phase shift to blue light was corrected for the free-run determined during the control session. The blue light PRC had a broad advance region starting in the morning and extending through the afternoon. The delay region started a few hours before bedtime and extended through the night. This is the first PRC to be constructed to blue light and to a stimulus that could be used in the real world.

New lighting and controls to save 67% at mall

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, K.

1985-06-17

A metal halide lighting system and a Staco control system that dims lighting in response to sunlight should save a Dallas hotel and office mall 67% in electricity costs. The new system replaces quartz lamps in the 160-foot-high atrium. The savings are a combination of state tax credits and lower air conditioning costs, which will pay for the $25,000 project in about 18 months. The metal halide system was chosen over sodium lighting in order to have more attractive color rendition and because it provides about twice as many lumens per watt as the quartz lamps. The Staco system willmore » dim lamps in response to outdoor light and turn lights above a skating rink on and off at prescribed times.« less

40 CFR 86.201-11 - General applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... new gasoline-fueled and diesel-fueled light-duty vehicles and light-duty trucks. (b) All of the... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium...

Light and nitrogen nutrition regulate apical control in Rosa hybrida L.

PubMed

Furet, Pierre-Maxime; Lothier, Jérémy; Demotes-Mainard, Sabine; Travier, Sandrine; Henry, Clémence; Guérin, Vincent; Vian, Alain

2014-03-01

Apical control is defined as the inhibition of basal axillary bud outgrowth by an upper actively growing axillary axis, whose regulation is poorly understood yet differs markedly from the better-known apical dominance. We studied the regulation of apical control by environmental factors in decapitated Rosa hybrida in order to remove the apical hormonal influence and nutrient sink. In this plant model, all the buds along the main axis have a similar morphology and are able to burst in vitro. We concentrated on the involvement of light intensity and nitrate nutrition on bud break and axillary bud elongation in the primary axis pruned above the fifth leaf of each rose bush. We observed that apical control took place in low light (92 μmol m(-2)s(-1)), where only the 2-apical buds grew out, both in low (0.25 mM) and high (12.25 mM) nitrate. In contrast, in high light (453 μmol m(-2)s(-1)), the apical control only operates in low nitrate while all the buds along the stem grew out when the plant was supplied with a high level of nitrate. We found a decreasing photosynthetic activity from the top to the base of the plant concomitant with a light gradient along the stem. The quantity of sucrose, fructose, glucose and starch are higher in high light conditions in leaves and stem. The expression of the sucrose transporter RhSUC2 was higher in internodes and buds in this lighting condition, suggesting an increased capacity for sucrose transport. We propose that light intensity and nitrogen availability both contribute to the establishment of apical control. Copyright © 2013 Elsevier GmbH. All rights reserved.

Driving platform for OLED lighting investigations

NASA Astrophysics Data System (ADS)

Vogel, Uwe; Elgner, Andreas; Kreye, Daniel; Amelung, Jörg; Scholles, Michael

2006-08-01

OLED technology may be excellently suitable for lighting applications by combining high efficiency, cost effective manufacturing and the use of low cost materials. Certain issues remain to be solved so far, including OLED brightness, color, lifetime, large area uniformity and encapsulation. Another aspect, that might be capable in addressing some of the mentioned issues, is OLED lighting electrical driving. We report on the design of a driving platform for OLED lighting test panels or substrates. It is intended for being a test environment for lighting substrates as well as demonstration/presentation environment. It is based on a 128-channel passive-matrix driver/controller ASIC OC2. Its key component is an MSP430-compatible 16-bit micro-controller core including embedded Flash memory (program), EEPROM (parameter), and RAM (data memory). A significant feature of the device is an electronic approach for improving the lifetime/uniformity behavior of connected OLED. The embedded micro-controller is the key to the high versatility of OC2, since by firmware modification it can be adapted to various applications and conditions. Here its application for an OLED lighting driving platform is presented. Major features of this platform are PC-control mode (via USB interface), stand-alone mode (no external control necessary, just power supply), on-board OLED panel parameter storage, flat geometry of OLED lighting panel carrier (board), AC and DC driving regimes, adjustable reverse voltage, dedicated user SW (PC/Windows-based), sub-tile patterning and single sub-tile control, combination of multiple channels for increasing driving current. This publication contains results of the project "High Brightness OLEDs for ICT & Next Generation Lighting Applications" (OLLA), funded by the European Commission.

Light-mediated control of DNA transcription in yeast

PubMed Central

Hughes, Robert M.; Bolger, Steven; Tapadia, Hersh; Tucker, Chandra L.

2012-01-01

A variety of methods exist for inducible control of DNA transcription in yeast. These include the use of native yeast promoters or regulatory elements that are responsive to small molecules such as galactose, methionine, and copper, or engineered systems that allow regulation by orthogonal small molecules such as estrogen. While chemically regulated systems are easy to use and can yield high levels of protein expression, they often provide imprecise control over protein levels. Moreover, chemically regulated systems can affect many other proteins and pathways in yeast, activating signaling pathways or physiological responses. Here, we describe several methods for light mediated control of DNA transcription in vivo in yeast. We describe methodology for using a red light and phytochrome dependent system to induce transcription of genes under GAL1 promoter control, as well as blue light / cryptochrome dependent systems to control transcription of genes under GAL1 promoter or LexA operator control. Light is dose dependent, inexpensive to apply, easily delivered, and does not interfere with cellular pathways, and thus has significant advantages over chemical systems. PMID:22922268

Shedding light on walking in the dark: the effects of reduced lighting on the gait of older adults with a higher-level gait disorder and controls.

PubMed

Kesler, Anat; Leibovich, Gregory; Herman, Talia; Gruendlinger, Leor; Giladi, Nir; Hausdorff, Jeffrey M

2005-08-28

To study the effects of reduced lighting on the gait of older adults with a high level gait disorder (HLGD) and to compare their response to that of healthy elderly controls. 22 patients with a HLGD and 20 age-matched healthy controls were studied under usual lighting conditions (1000 lumens) and in near darkness (5 lumens). Gait speed and gait dynamics were measured under both conditions. Cognitive function, co-morbidities, depressive symptoms, and vision were also evaluated. Under usual lighting conditions, patients walked more slowly, with reduced swing times, and increased stride-to-stride variability, compared to controls. When walking under near darkness conditions, both groups slowed their gait. All other measures of gait were not affected by lighting in the controls. In contrast, patients further reduced their swing times and increased their stride-to-stride variability, both stride time variability and swing time variability. The unique response of the patients was not explained by vision, mental status, co-morbidities, or the values of walking under usual lighting conditions. Walking with reduced lighting does not affect the gait of healthy elderly subjects, except for a reduction in speed. On the other hand, the gait of older adults with a HLGD becomes more variable and unsteady when they walk in near darkness, despite adapting a slow and cautious gait. Further work is needed to identify the causes of the maladaptive response among patients with a HLGD and the potential connection between this behavior and the increased fall risk observed in these patients.

Effective Light Directed Assembly of Building Blocks with Microscale Control.

PubMed

Dinh, Ngoc-Duy; Luo, Rongcong; Christine, Maria Tankeh Asuncion; Lin, Weikang Nicholas; Shih, Wei-Chuan; Goh, James Cho-Hong; Chen, Chia-Hung

2017-06-01

Light-directed forces have been widely used to pattern micro/nanoscale objects with precise control, forming functional assemblies. However, a substantial laser intensity is required to generate sufficient optical gradient forces to move a small object in a certain direction, causing limited throughput for applications. A high-throughput light-directed assembly is demonstrated as a printing technology by introducing gold nanorods to induce thermal convection flows that move microparticles (diameter = 40 µm to several hundreds of micrometers) to specific light-guided locations, forming desired patterns. With the advantage of effective light-directed assembly, the microfluidic-fabricated monodispersed biocompatible microparticles are used as building blocks to construct a structured assembly (≈10 cm scale) in ≈2 min. The control with microscale precision is approached by changing the size of the laser light spot. After crosslinking assembly of building blocks, a novel soft material with wanted pattern is approached. To demonstrate its application, the mesenchymal stem-cell-seeded hydrogel microparticles are prepared as functional building blocks to construct scaffold-free tissues with desired structures. This light-directed fabrication method can be applied to integrate different building units, enabling the bottom-up formation of materials with precise control over their internal structure for bioprinting, tissue engineering, and advanced manufacturing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthetic dual-input mammalian genetic circuits enable tunable and stringent transcription control by chemical and light.

PubMed

Chen, Xianjun; Li, Ting; Wang, Xue; Du, Zengmin; Liu, Renmei; Yang, Yi

2016-04-07

Programmable transcription factors can enable precise control of gene expression triggered by a chemical inducer or light. To obtain versatile transgene system with combined benefits of a chemical inducer and light inducer, we created various chimeric promoters through the assembly of different copies of the tet operator and Gal4 operator module, which simultaneously responded to a tetracycline-responsive transcription factor and a light-switchable transactivator. The activities of these chimeric promoters can be regulated by tetracycline and blue light synergistically or antagonistically. Further studies of the antagonistic genetic circuit exhibited high spatiotemporal resolution and extremely low leaky expression, which therefore could be used to spatially and stringently control the expression of highly toxic protein Diphtheria toxin A for light regulated gene therapy. When transferring plasmids engineered for the gene switch-driven expression of a firefly luciferase (Fluc) into mice, the Fluc expression levels of the treated animals directly correlated with the tetracycline and light input program. We suggest that dual-input genetic circuits using TET and light that serve as triggers to achieve expression profiles may enable the design of robust therapeutic gene circuits for gene- and cell-based therapies. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

The Control of Lighting Heat

ERIC Educational Resources Information Center

Modern Schools, 1973

1973-01-01

The trend toward increased lighting has accelerated the acceptance of heat recovery systems. A heating-lighting-cooling system is a responsible and efficient use of energy for future school buildings. (Author/MLF)

Lighting Control System for Premises with Display Screen Equipment

NASA Astrophysics Data System (ADS)

Kudryashov, A. V.

2017-11-01

The use of Display Screen Equipment (DSE) at enterprises allows one to increase the productivity and safety of production, minimize the number of personnel and leads to the simplification of the work of specialists, but on the other side, changes usual working conditions. If the personnel works with displays, visual fatigue develops more quickly which contributes to the emergence of nervous tension, stress and possible erroneous actions. Low interest of the lighting control system developers towards the rooms with displays is dictated by special requirements for coverage by sanitary and hygienic standards (limiting excess workplace illumination). We decided to create a combined lighting system which works considering daylight illumination and artificial light sources. The brightness adjustment of the LED lamps is carried out according to the DALI protocol, adjustment of the natural illumination by means of smart glasses. The technical requirements for a lighting control system, the structural-functional scheme and the algorithm for controlling the operation of the system have been developed. The elements of control units, sensors and actuators have been selected.

The lantern shark's light switch: turning shallow water crypsis into midwater camouflage

PubMed Central

Claes, Julien M.; Mallefet, Jérôme

2010-01-01

Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment. PMID:20410033

Light Regulation of the Arabidopsis Respiratory Chain. Multiple Discrete Photoreceptor Responses Contribute to Induction of Type II NAD(P)H Dehydrogenase Genes1

PubMed Central

Escobar, Matthew A.; Franklin, Keara A.; Svensson, Å. Staffan; Salter, Michael G.; Whitelam, Garry C.; Rasmusson, Allan G.

2004-01-01

Controlled oxidation reactions catalyzed by the large, proton-pumping complexes of the respiratory chain generate an electrochemical gradient across the mitochondrial inner membrane that is harnessed for ATP production. However, several alternative respiratory pathways in plants allow the maintenance of substrate oxidation while minimizing the production of ATP. We have investigated the role of light in the regulation of these energy-dissipating pathways by transcriptional profiling of the alternative oxidase, uncoupling protein, and type II NAD(P)H dehydrogenase gene families in etiolated Arabidopsis seedlings. Expression of the nda1 and ndc1 NAD(P)H dehydrogenase genes was rapidly up-regulated by a broad range of light intensities and qualities. For both genes, light induction appears to be a direct transcriptional effect that is independent of carbon status. Mutant analyses demonstrated the involvement of two separate photoreceptor families in nda1 and ndc1 light regulation: the phytochromes (phyA and phyB) and an undetermined blue light photoreceptor. In the case of the nda1 gene, the different photoreceptor systems generate distinct kinetic induction profiles that are integrated in white light response. Primary transcriptional control of light response was localized to a 99-bp region of the nda1 promoter, which contains an I-box flanked by two GT-1 elements, an arrangement prevalent in the promoters of photosynthesis-associated genes. Light induction was specific to nda1 and ndc1. The only other substantial light effect observed was a decrease in aox2 expression. Overall, these results suggest that light directly influences the respiratory electron transport chain via photoreceptor-mediated transcriptional control, likely for supporting photosynthetic metabolism. PMID:15333756

Manipulation of light wavelength at appropriate growth stage to enhance biomass productivity and fatty acid methyl ester yield using Chlorella vulgaris.

PubMed

Kim, Dae Geun; Lee, Changsu; Park, Seung-Moon; Choi, Yoon-E

2014-05-01

LEDs light offer several advantages over the conventional lamps, thereby being considered as the optimal light sources for microalgal cultivation. In this study, various light-emitting diodes (LEDs) especially red and blue color with different light wavelengths were employed to explore the effects of light source on phototrophic cultivation of Chlorella vulgaris. Blue light illumination led to significantly increased cell size, whereas red light resulted in small-sized cell with active divisions. Based on the discovery of the effect of light wavelengths on microalgal biology, we then applied appropriate wavelength at different growth stages; blue light was illuminated first and then shifted to red light. By doing so, biomass and lipid productivity of C. vulgaris could be significantly increased, compared to that in the control. These results will shed light on a novel approach using LED light for microalgal biotechnology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Double-layered liquid crystal light shutter for control of absorption and scattering of the light incident to a transparent display device

NASA Astrophysics Data System (ADS)

Huh, Jae-Won; Yu, Byeong-Hun; Shin, Dong-Myung; Yoon, Tae-Hoon

2015-03-01

Recently, a transparent display has got much attention as one of the next generation display devices. Especially, active studies on a transparent display using organic light-emitting diodes (OLEDs) are in progress. However, since it is not possible to obtain black color using a transparent OLED, it suffers from poor visibility. This inevitable problem can be solved by using a light shutter. Light shutter technology can be divided into two types; light absorption and scattering. However, a light shutter based on light absorption cannot block the background image perfectly and a light shutter based on light scattering cannot provide black color. In this work we demonstrate a light shutter using two liquid crystal (LC) layers, a light absorption layer and a light scattering layer. To realize a light absorption layer and a light scattering layer, we use the planar state of a dye-doped chiral nematic LC (CNLC) cell and the focal-conic state of a long-pitch CNLC cell, respectively. The proposed light shutter device can block the background image perfectly and show black color. We expect that the proposed light shutter can increase the visibility of a transparent display.

Phototaxis of larval and juvenile northern pike

USGS Publications Warehouse

Zigler, S.J.; Dewey, M.R.

1995-01-01

Age- Phi northern pike Esox lucius prefer vegetated habitats that are difficult to sample with standard towed gears. Light traps can be effective for sampling larval fishes in dense vegetation, given positive phototaxis of fish. We evaluated the phototactic response of young northern pike by comparing the catches of larvae and juveniles obtained with plexiglass traps deployed with a chemical light stick versus traps deployed without a light source (controls) in a laboratory raceway and in a vegetated pond. In the laboratory tests, catches of protolarvae and mesolarvae in lighted traps were 11-35 times greater than catches in control traps. The catches of juvenile northern pike in field and laboratory experiments were 3-15 times greater in lighted traps than in control traps, even though the maximum body width of the larger juveniles was similar to the width of the entrance slots of the traps (5 mm). Larval and juvenile northern pike were photopositive; thus, light traps should effectively sample age-0 northern pike for at least 6 weeks after hatching.

Facile fabrication of BiVO4 nanofilms with controlled pore size and their photoelectrochemical performances

NASA Astrophysics Data System (ADS)

Feng, Chenchen; Jiao, Zhengbo; Li, Shaopeng; Zhang, Yan; Bi, Yingpu

2015-12-01

We demonstrate a facile method for the rational fabrication of pore-size controlled nanoporous BiVO4 photoanodes, and confirmed that the optimum pore-size distributions could effectively absorb visible light through light diffraction and confinement functions. Furthermore, in situ X-ray photoelectron spectroscopy (XPS) reveals more efficient photoexcited electron-hole separation than conventional particle films, induced by light confinement and rapid charge transfer in the inter-crossed worm-like structures.We demonstrate a facile method for the rational fabrication of pore-size controlled nanoporous BiVO4 photoanodes, and confirmed that the optimum pore-size distributions could effectively absorb visible light through light diffraction and confinement functions. Furthermore, in situ X-ray photoelectron spectroscopy (XPS) reveals more efficient photoexcited electron-hole separation than conventional particle films, induced by light confinement and rapid charge transfer in the inter-crossed worm-like structures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06584d

Photic Resetting and Entrainment in CLOCK-Deficient Mice

PubMed Central

Dallmann, Robert; DeBruyne, Jason P.; Weaver, David R.

2012-01-01

Mice lacking CLOCK protein have a relatively subtle circadian phenotype, including a slightly shorter period in constant darkness, differences in phase resetting after 4-hr light pulses in the early and late night, and a variably advanced phase angle of entrainment in a light-dark (LD) cycle (DeBruyne et al., Neuron 50:465–477, 2006). The present series of experiments was conducted to more fully characterize the circadian phenotype of Clock−/− mice under various lighting conditions. A phase-response curve (PRC) to 4-hour light pulses in free-running mice was conducted; the results confirm that Clock−/− mice exhibit very large phase advances after 4 hrs light pulses in the late subjective night, but have relatively normal responses to light at other phases. The abnormal shape of the PRC to light may explain the tendency of CLOCK-deficient mice to begin activity before lights-out when housed in a 12 hrs light: 12 hrs dark lighting schedule. To assess this relationship further, Clock−/− and wild-type control mice were entrained to skeleton lighting cycles (1L:23D, and 1L:10D:1L:12D). Comparing entrainment under the two types of skeleton photoperiods revealed that exposure to 1 hr light in the morning leads to a phase advance of activity onset (expressed the following afternoon) in Clock−/− mice, but not in the controls. Constant light typically causes an intensity-dependent increase in circadian period in mice, but this did not occur in CLOCK-deficient mice. The failure of Clock−/− mice to respond to the period-lengthening effect of constant light likely results from the increased functional impact of light falling in the phase advance zone of the PRC. Collectively, these experiments reveal that alterations in the response of CLOCK-deficient mice to light in several paradigms are likely due to an imbalance in the shape of the PRC to light. PMID:21921293

Applications of Light-Responsive Systems for Cancer Theranostics.

PubMed

Chen, Hongzhong; Zhao, Yanli

2018-06-27

Achieving controlled and targeted delivery of chemotherapeutic drugs and other therapeutic agents to tumor sites is challenging. Among many stimulus strategies, light as a mode of action shows various advantages such as high spatiotemporal selectivity, minimal invasiveness and easy operation. Thus, drug delivery systems (DDSs) have been designed with the incorporation of various functionalities responsive to light as an exogenous stimulus. Early development has focused on guiding chemotherapeutic drugs to designated location, followed by the utilization of UV irradiation for controlled drug release. Because of the disadvantages of UV light such as phototoxicity and limited tissue penetration depth, scientists have moved the research focus onto developing nanoparticle systems responsive to light in the visible region (400-700 nm), aiming to reduce the phototoxicity. In order to enhance the tissue penetration depth, near-infrared light triggered DDSs become increasingly important. In addition, light-based advanced systems for fluorescent and photoacoustic imaging, as well as photodynamic and photothermal therapy have also been reported. Herein, we highlight some of recent developments by applying light-responsive systems in cancer theranostics, including light activated drug release, photodynamic and photothermal therapy, and bioimaging techniques such as fluorescent and photoacoustic imaging. Future prospect of light-mediated cancer treatment is discussed at the end of the review. This Spotlights on Applications article aims to provide up-to-date information about the rapidly developing field of light-based cancer theranostics.

Disruption of Circadian Rhythms by Light During Day and Night.

PubMed

Figueiro, Mariana G

2017-06-01

This study aims to discuss possible reasons why research to date has not forged direct links between light at night, acute melatonin suppression or circadian disruption, and risks for disease. Data suggest that irregular light-dark patterns or light exposures at the wrong circadian time can lead to circadian disruption and disease risks. However, there remains an urgent need to: (1) specify light stimulus in terms of circadian rather than visual response; (2) when translating research from animals to humans, consider species-specific spectral and absolute sensitivities to light; (3) relate the characteristics of photometric measurement of light at night to the operational characteristics of the circadian system; and (4) examine how humans may be experiencing too little daytime light, not just too much light at night. To understand the health effects of light-induced circadian disruption, we need to measure and control light stimulus during the day and at night.

Hybrid daylight/light-emitting diode illumination system for indoor lighting.

PubMed

Ge, Aiming; Qiu, Peng; Cai, Jinlin; Wang, Wei; Wang, Junwei

2014-03-20

A hybrid illumination method using both daylight and light-emitting diodes (LEDs) for indoor lighting is presented in this study. The daylight can be introduced into the indoor space by a panel-integration system. The daylight part and LEDs are combined within a specific luminaire that can provide uniform illumination. The LEDs can be turned on and dimmed through closed-loop control when the daylight illuminance is inadequate. We simulated the illumination and calculated the indoor lighting efficiency of our hybrid daylight and LED lighting system, and compared this with that of LED and fluorescent lighting systems. Simulation results show that the efficiency of the hybrid daylight/LED illumination method is better than that of LED and traditional lighting systems, under the same lighting conditions and lighting time; the method has hybrid lighting average energy savings of T5 66.28%, and that of the LEDs is 41.62%.

Computational Modeling to Limit the Impact Displays and Indicator Lights Have on Habitable Volume Operational Lighting Constraints

NASA Technical Reports Server (NTRS)

Clark, T. A.; Salazar, G. A.; Brainard, G. C.; Litaker, H. L.; Hanifin, J.; Schwing, B. M.

2016-01-01

Even with no ambient lighting system "on", the International Space Station glows at night. The glow is caused by indicator lamps and displays that are not included with the specification of the ambient lighting system. How does this impact efforts to improve the astronaut's lighting environment to promote more effective sleep patterns? Do the extra indicators and displays add enough light to change the spectrum of light the crew sees during the day as well? If spacecraft environments are specifically engineered to have an ambient lighting system that emits a spectrum promoting a healthy circadian response, is there a way control the impact? The goal of this project is to investigate how additional light sources, such as displays and indicators change the effective light spectrum of the architectural lighting system and how impacts can be mitigated.

A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments

PubMed Central

2017-01-01

Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because—in nature—photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded by At4g02530) is required for growth acclimation of Arabidopsis thaliana plants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented that mph2 mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover, mph2—and previously characterized PSII repair-defective mutants—exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair. PMID:28874535

Light and maternal influence in the entrainment of activity circadian rhythm in infants 4-12 weeks of age.

PubMed

Thomas, Karen A; Burr, Robert L; Spieker, Susan

2016-07-01

The influence of light and maternal activity on early infant activity rhythm were studied in 43 healthy, maternal-infant pairs. Aims included description of infant and maternal circadian rhythm of environmental light, assessing relations among of activity and light circadian rhythm parameters, and exploring the influence of light on infant activity independent of maternal activity. Three-day light and activity records were obtained using actigraphy monitors at infant ages 4, 8, and 12 weeks. Circadian rhythm timing, amplitude, 24-hour fit, rhythm center, and regularity were determined using cosinor and nonparametric circadian rhythm analyses (NPCRA). All maternal and infant circadian parameters for light were highly correlated. When maternal activity was controlled, the partial correlations between infant activity and light rhythm timing, amplitude, 24-hour fit, and rhythm center demonstrated significant relation (r = .338 to .662) at infant age 12 weeks, suggesting entrainment. In contrast, when maternal light was controlled there was significant relation between maternal and infant activity rhythm (r = 0.470, 0.500, and 0.638 at 4, 8 and 12 weeks, respectively) suggesting the influence of maternal-infant interaction independent of photo entrainment of cycle timing over the first 12 weeks of life. Both light and maternal activity may offer avenues for shaping infant activity rhythm during early infancy.

Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students.

PubMed

Figueiro, Mariana G; Rea, Mark S

2010-01-01

Circadian timing affects sleep onset. Delayed sleep onset can reduce sleep duration in adolescents required to awake early for a fixed school schedule. The absence of short-wavelength ("blue") morning light, which helps entrain the circadian system, can hypothetically delay sleep onset and decrease sleep duration in adolescents. The goal of this study was to investigate whether removal of short-wavelength light during the morning hours delayed the onset of melatonin in young adults. Dim light melatonin onset (DLMO) was measured in eleven 8th-grade students before and after wearing orange glasses, which removed short-wavelength light, for a five-day school week. DLMO was significantly delayed (30 minutes) after the five-day intervention, demonstrating that short-wavelength light exposure during the day can be important for advancing circadian rhythms in students. Lack of short-wavelength light in the morning has been shown to delay the circadian clock in controlled laboratory conditions. The results presented here are the first to show, outside laboratory conditions, that removal of short-wavelength light in the morning hours can delay DLMO in 8th-grade students. These field data, consistent with results from controlled laboratory studies, are directly relevant to lighting practice in schools.

A chloroplast thylakoid lumen protein is required for proper photosynthetic acclimation of plants under fluctuating light environments.

PubMed

Liu, Jun; Last, Robert L

2017-09-19

Despite our increasingly sophisticated understanding of mechanisms ensuring efficient photosynthesis under laboratory-controlled light conditions, less is known about the regulation of photosynthesis under fluctuating light. This is important because-in nature-photosynthetic organisms experience rapid and extreme changes in sunlight, potentially causing deleterious effects on photosynthetic efficiency and productivity. Here we report that the chloroplast thylakoid lumenal protein MAINTENANCE OF PHOTOSYSTEM II UNDER HIGH LIGHT 2 (MPH2; encoded by At4g02530 ) is required for growth acclimation of Arabidopsis thaliana plants under controlled photoinhibitory light and fluctuating light environments. Evidence is presented that mph2 mutant light stress susceptibility results from a defect in photosystem II (PSII) repair, and our results are consistent with the hypothesis that MPH2 is involved in disassembling monomeric complexes during regeneration of dimeric functional PSII supercomplexes. Moreover, mph2 -and previously characterized PSII repair-defective mutants-exhibited reduced growth under fluctuating light conditions, while PSII photoprotection-impaired mutants did not. These findings suggest that repair is not only required for PSII maintenance under static high-irradiance light conditions but is also a regulatory mechanism facilitating photosynthetic adaptation under fluctuating light environments. This work has implications for improvement of agricultural plant productivity through engineering PSII repair.

Effect of Twice-Daily Blue Light Treatment on Matrix-Rich Biofilm Development.

PubMed

de Sousa, Denise Lins; Lima, Ramille Araújo; Zanin, Iriana Carla; Klein, Marlise I; Janal, Malvin N; Duarte, Simone

2015-01-01

The use of blue light has been proposed as a direct means of affecting local bacterial infections, however the use of blue light without a photosensitizer to prevent the biofilm development has not yet been explored. The aim of this study was to determine how the twice-daily treatment with blue light affects the development and composition of a matrix-rich biofilm. Biofilms of Streptococcus mutans UA159 were formed on saliva-coated hydroxyapatite discs for 5 days. The biofilms were exposed twice-daily to non-coherent blue light (LumaCare; 420 nm) without a photosensitizer. The distance between the light and the sample was 1.0 cm; energy density of 72 J cm-2; and exposure time of 12 min 56 s. Positive and negative controls were twice-daily 0.12% chlorhexidine (CHX) and 0.89% NaCl, respectively. Biofilms were analyzed for bacterial viability, dry-weight, and extra (EPS-insoluble and soluble) and intracellular (IPS) polysaccharides. Variable pressure scanning electron microscopy and confocal scanning laser microscopy were used to check biofilm morphology and bacterial viability, respectively. When biofilms were exposed to twice-daily blue light, EPS-insoluble was reduced significantly more than in either control group (CHX and 0.89% NaCl). Bacterial viability and dry weight were also reduced relative to the negative control (0.89% NaCl) when the biofilms were treated with twice-daily blue light. Different morphology was also visible when the biofilms were treated with blue light. Twice-daily treatment with blue light without a photosensitizer is a promising mechanism for the inhibition of matrix-rich biofilm development.

Responses of Crepis japonica induced by supplemental blue light and UV-A radiation.

PubMed

Constantino, L F da S; Nascimento, L B Dos S; Casanova, L M; Moreira, N Dos S; Menezes, E A; Esteves, R L; Costa, S S; Tavares, E S

2017-02-15

Crepis japonica (L.) D.C. (Asteraceae), a weed with antioxidant, antiallergenic, antiviral and antitumor properties displays both medicinal properties and nutritional value. This study aims to assess the effects of a supplementation of blue light and UV-A radiation on the growth, leaf anatomical structure and phenolic profile of the aerial parts of Crepis japonica. Plants were grown under two light treatments: W (control - white light), W + B (white light supplemented with blue light) and W + UV-A (white light supplemented with UV-A radiation). We recorded the length, width, and weight of fresh and dry leaves, the thickness of the epidermis and mesophyll, and stomata density. The phenolic profiles of the aqueous extracts of the aerial parts were analyzed by HPLC-DAD. There was an increase in the leaf size, stomatal density, and phenolic production, and a thickening of the mesophyll and epidermis. UV-A radiation increased the phenolic production more than blue light. Blue light and UV-A radiation both improved the production of caffeic acid by about 6 and 3 times, respectively, in comparison to control. This compound was first reported as a constituent of the extract from the aerial parts together with caftaric acid. UV-A also promoted the production of chlorogenic acid (about 1.5 times in comparison to the control). We observed that the morphological and chemical parameters of C. japonica are modified in response to blue light and UV-A radiation, which can be used as tools in the cultivation of this species in order to improve its medicinal properties and nutritional value.

High-Fluence Light-Emitting Diode-Generated Red Light Modulates the Transforming Growth Factor-Beta Pathway in Human Skin Fibroblasts.

PubMed

Mamalis, Andrew; Jagdeo, Jared

2018-05-24

Skin fibrosis is a significant medical problem with limited available treatment modalities. The key cellular characteristics include increased fibroblast proliferation, collagen production, and transforming growth factor-beta (TGF-B)/SMAD pathway signaling. The authors have previously shown that high-fluence light-emitting diode red light (HF-LED-RL) decreases cellular proliferation and collagen production. Herein, the authors investigate the ability of HF-LED-RL to modulate the TGF-B/SMAD pathway. Normal human dermal fibroblasts were cultured and irradiated with a commercially available hand-held LED array. After irradiation, cell lysates were collected and levels of pSMAD2, TGF-Beta 1, and TGF-Beta I receptor were measured using Western blot. High-fluence light-emitting diode red light decreased TGF-Beta 1 ligand (TGF-B1) levels after irradiation. 320 J/cm HF-LED-RL resulted in 59% TGF-B1 and 640 J/cm HF-LED-RL resulted in 54% TGF-B1, relative to controls. 640 J/cm HF-LED-RL resulted in 62% pSMAD2 0 hours after irradiation, 65% pSMAD2 2 hours after irradiation, and 95% 4 hours after irradiation, compared with matched controls. High-fluence light-emitting diode red light resulted in no significant difference in transforming growth factor-beta receptor I levels compared with matched controls. Skin fibrosis is a significant medical problem with limited available treatment modalities. Light-emitting diode-generated red light is a safe, economic, and noninvasive modality that has a body of in vitro evidence supporting the reduction of key cellular characteristics associated with skin fibrosis.

Modeling of an Adjustable Beam Solid State Light Project

NASA Technical Reports Server (NTRS)

Clark, Toni

2015-01-01

This proposal is for the development of a computational model of a prototype variable beam light source using optical modeling software, Zemax Optics Studio. The variable beam light source would be designed to generate flood, spot, and directional beam patterns, while maintaining the same average power usage. The optical model would demonstrate the possibility of such a light source and its ability to address several issues: commonality of design, human task variability, and light source design process improvements. An adaptive lighting solution that utilizes the same electronics footprint and power constraints while addressing variability of lighting needed for the range of exploration tasks can save costs and allow for the development of common avionics for lighting controls.

Cavities shield birds from effects of artificial light at night on sleep.

PubMed

Raap, Thomas; Pinxten, Rianne; Eens, Marcel

2018-05-20

Light pollution is an ever increasing worldwide problem disrupting animal behavior. Artificial light at night (ALAN) has been shown to affect sleep in wild birds. Even cavity-nesting bird species may be affected when sleeping inside their cavity. Correlational studies suggest that light from outside the cavity/nest box, for example from street lights, may affect sleep. We used an experimental design to study to what extent nest boxes shield animals from effects of ALAN on sleep. We recorded individual sleep behavior of free-living great tits (Parus major) that were roosting in dark nest boxes and exposed their nest box entrance to ALAN the following night (1.6 lux white LED light; a similar light intensity as was found at nest boxes near street lights). Their behavior was compared to that of control birds sleeping in dark nest boxes on both nights. Our experimental treatment did not affect sleep behavior. Sleep behavior of birds in the control group did not differ from that of individuals in the light treated group. Our results suggest that during winter cavities shield birds from some effects of ALAN. Furthermore, given that effects of ALAN and exposure to artificial light are species-, sex-, and season-dependent, it is important that studies using wild animals quantify individual exposure to light pollution, and be cautious in the interpretation and generalization of the effects, or lack thereof, from light pollution. Rigorous studies are necessary to examine individual light exposure and its consequences in cavity- and open-nesting birds. © 2018 Wiley Periodicals, Inc.

BLAM (Benthic Light Availability Model): A Proposed Model of Hydrogeomorphic Controls on Light in Rivers

NASA Astrophysics Data System (ADS)

Julian, J. P.; Doyle, M. W.; Stanley, E. H.

2006-12-01

Light is vital to the dynamics of aquatic ecosystems. It drives photosynthesis and photochemical reactions, affects thermal structure, and influences behavior of aquatic biota. Despite the fundamental role of light to riverine ecosystems, light studies in rivers have been mostly neglected because i) boundary conditions (e.g., banks, riparian vegetation) make ambient light measurements difficult, and ii) the optical water quality of rivers is highly variable and difficult to characterize. We propose a benthic light availability model (BLAM) that predicts the percent of incoming photosynthetically active radiation (PAR) available at the river bed. BLAM was developed by quantifying light attenuation of the five hydrogeomorphic controls that dictate riverine light availability: topography, riparian vegetation, channel geometry, optical water quality, and water depth. BLAM was calibrated using hydrogeomorphic data and light measurements from two rivers: Deep River - a 5th-order, turbid river in central North Carolina, and Big Spring Creek - a 2nd-order, optically clear stream in central Wisconsin. We used a series of four PAR sensors to measure i) above-canopy PAR, ii) PAR above water surface, iii) PAR below water surface, and iv) PAR on stream bed. These measurements were used to develop empirical light attenuation coefficients, which were then used in combination with optical water quality measurements, shading analyses, channel surveys, and flow records to quantify the spatial and temporal variability in riverine light availability. Finally, we apply BLAM to the Baraboo River - a 6th-order, 120-mile, unimpounded river in central Wisconsin - in order to characterize light availability along the river continuum (from headwaters to mouth).

Psychophysical investigations of discomfort and disability glare from underground coal mine illumination systems. Open File Report, May 1980-July 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitehead, K.L.; Lindahl, P.; Vincent, R.

1983-10-01

A literature search was conducted to identify current light-control technology and hardware that may be applicable on underground lighting systems to minimize disability and discomfort glare. No research dealing specifically with mine lighting was found, but abstracts on research considered potentially applicable are included in the report. Information on several commercial light-control products for use in controlling glare are also included. Vision tests conducted on 137 mine personnel to determine their discomfort and disability glare sensitivity indicate their sensitivity to disability glare is about the same as the general population.

40 CFR 86.1848-10 - Certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and... be covered by the certificate. (4) For incomplete light-duty trucks and incomplete heavy-duty...

Spectrally resolved infrared microscopy and chemometric tools to reveal the interaction between blue light (470nm) and methicillin-resistant Staphylococcus aureus.

PubMed

Bumah, Violet V; Aboualizadeh, Ebrahim; Masson-Meyers, Daniela S; Eells, Janis T; Enwemeka, Chukuka S; Hirschmugl, Carol J

2017-02-01

Blue light inactivates methicillin-resistant Staphylococcus aureus (MRSA), a Gram-positive antibiotic resistant bacterium that leads to fatal infections; however, the mechanism of bacterial death remains unclear. In this paper, to uncover the mechanism underlying the bactericidal effect of blue light, a combination of Fourier transform infrared (FTIR) spectroscopy and chemometric tools is employed to detect the photoreactivity of MRSA and its distinctive pathway toward apoptosis after treatment. The mechanism of action of UV light and vancomycin against MRSA is also investigated to support the findings. Principal component analysis followed by linear discriminant analysis (PCA- LDA) is employed to reveal clustering of five groups of MRSA samples, namely untreated (control I), untreated and incubated at ambient air (control II), irradiated with 470nm blue light, irradiated with 253.5 UV light, and vancomycin-treated MRSA. Loadings plot from PCA-LDA analysis reveals important functional groups in proteins (1683, 1656, 1596, 1542cm -1 ), lipids (1743, 1409cm -1 ), and nucleic acids region of the spectrum (1060, 1087cm -1 ) that are responsible for the classification of blue light irradiated spectra and control spectra. Cluster vector plots and scores plot reveals that UV light-irradiated spectra are the most biochemically similar to blue light- irradiated spectra; however, some wavenumbers experience a shift. The shifts between blue light and UV light irradiated loadings plot at ν asym PO 2- band (from 1228 to 1238cm -1 ), DNA backbone (from 970 to 966cm -1 ) and base pairing vibration of DNA (from 1717 to 1712cm -1 ) suggest distinctive changes in DNA conformation in response to irradiation. Our findings indicate that irradiation of MRSA with 470nm light induces A-DNA cleavage and that B-DNA is more resistant to damage by blue light. Blue light and UV light treatment of MRSA are complementary and distinct from the known antimicrobial effect of vancomycin. Moreover, it is known that UV-induced cleavage of DNA predominantly targets B-DNA, which is in agreement with the FTIR findings. Overall the results suggest that the combination of light and vancomycin could be a more robust approach in treating MRSA infections. Published by Elsevier B.V.

2001 Gordon Research Conference on Quantum Control of Light and Matter. Final progress report [agenda and attendee list

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, Moshe

2001-08-03

The Gordon Research Conference on Quantum Control of Light and Matter [Quantum Control of Atomic and Molecular Motion] was held at Mount Holyoke College, South Hadley, Massachusetts, July 29 - August 3, 2001. The conference was attended by 119 participants. The attendees represented the spectrum of endeavor in this field, coming from academia, industry, and government laboratories, and included US and foreign scientists, senior researchers, young investigators, and students. Emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate discussion about the key issues in themore » field today. Session topics included the following: General perspectives, Phase control, Optimal control, Quantum information, Light manipulation and manipulation with light, Control in the condensed phase, Strong field control, Laser cooling and Bose-Einstein Condensate dynamics, and Control in the solid phase.« less

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks

NASA Astrophysics Data System (ADS)

Gul, M. Shahzeb Khan; Gunturk, Bahadir K.

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks.

PubMed

Gul, M Shahzeb Khan; Gunturk, Bahadir K

2018-05-01

Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

The effects of feedback lighting on the circadian rhythm of locomotor activity and the reproductive maturation of the male Djungarian hamster (Phodopus sungorus)

NASA Technical Reports Server (NTRS)

Ferraro, J. S.

1988-01-01

The non-parametric model of entrainment suggests that brief pulses of light, delivered between dusk and dawn can simulate the phasing effects of full photoperiods or even constant light (LL). Feedback lighting (LDFB) is a lighting condition where individual animals, otherwise in constant darkness (DD), are exposed to light in response to a monitored behavior. The specific purpose of this type of illumination is to expose the circadian cycle to light only during the subjective night. LDFB has been used to support this hypothesis in several species of nocturnal rodents and one species of diurnal primate by producing similar free-running periods in LDFB as in LL. This lighting condition has also been used to test the hypothesis that exposing the subjective night to even short duration light pulses will maintain reproductive function in long day breeders. In the Syrian hamster (Mesocricetus auratus), however, LDFB is not as photostimulatory as LL despite extensive light exposure during the subjective night. In the experiments presented here, a group of immature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight sound attenuated chambers where they had free access to food, water and an activity wheel. The animals were exposed to one of four lighting conditions [DD, LL, LDFB or a neighbor control of feedback lighting (LDFB NC)] for approximately 30 days shortly after weaning. LDFB NC is a lighting condition where a neighbor control hamster receives the identical lighting regime as a paired animal exposing itself to LDFB, yet the neighbor has no control over it. A fifth group was exposed to a light-dark cycle of 16 hours of light and 8 hours of dark (LD16:8). This group was housed in cages in a colony room and did not have access to a running wheel. The free-running periods of the locomotor activity rhythms for hamsters exposed to LDFB and LL were not similar, unlike the results for rats, Syrian hamsters, mice, monkeys and even mature Djungarian hamsters. Immature hamsters exposed to DD and LDFB NC developed more slowly than animals exposed to LL or LD16:8, while hamsters in LDFB developed at an intermediate rate. Thus, it appears that LDFB, although capable of inducing reproductive function in immature Djungarian hamsters, is not as photostimulatory as may have been expected from current photoperiodic models, despite substantial light exposure during the subjective night. Furthermore, this data may suggest that the circadian system of 18-48 day old Djungarian hamsters are still undergoing organizational maturation.

Photocontrol of Spirodela intermedia flavonoids 1

PubMed Central

McClure, Jerry W.

1968-01-01

Clone 115 of Spirodela intermedia W. Koch grown in Hutner's medium with sucrose produces the glycoflavones vitexin and orientin in darkness or in light of various wavelengths. The anthocyanin cyanidin-3-monoglucoside was present only after prolonged illumination of the plants with white or blue light. No cyanidin-glucoside was formed under constant red light. The substitution of red, blue, or far-red light for the last 24 hours of culture under constant white light reduced each flavonoid over those maintained in white light or given 24 hours of darkness. Reducing the light intensity from 900 to 400 ft-c of constant cool-white fluorescent light had no appreciable influence on vitexin (4′-hydroxyl) but markedly reduced orientin and cyanidin-glucoside (both 3′4′-hydroxyl). Substituting alternate 12-hour periods of light and darkness for continuous light reduced the glycoflavones approximately 50% while cyanidin-glucoside was reduced about 85%. Most responses to red, blue, or far-red light are consistent with a phytochrome-controlled promotion of vitexin synthesis. The evidence suggests that in S. intermedia: A) Environmental conditions which elicit cyanidin-glucoside and glycoflavone synthesis are different since a prolonged illumination with white light is required for the former but not the latter. B) The availability of a 3′4′-hydroxyl precursor for orientin and anthocyanin probably limits their synthesis in low intensity light. Since vitexin is essentially unaltered under these conditions this also suggests that acetate or malonate units for the A-ring and the deamination products of aromatic amino acids for the B-ring and carbons of the C-ring are not limiting factors. C) Light controls the biosynthesis of flavonols in the same manner as glycoflavones; under all experimental conditions the synthesis of kaempferol paralleled vitexin while quercetin responded in the same manner as crientin. PMID:16656751

Light sources and output couplers for a backlight with switchable emission angles

NASA Astrophysics Data System (ADS)

Fujieda, Ichiro; Imai, Keita; Takagi, Yoshihiko

2007-09-01

For switching viewing angles of a liquid crystal display, we proposed to place a liquid crystal device between an LED and a light-guide of a backlight. The first key component for this configuration is a light source with electronically-controlled emission angles. Here, we construct such a device by stacking an optical film and a polymer-network liquid crystal (PNLC) cell on top of a chip-type LED. The optical film contains opaque parallel plates that limit the LED output in a narrow angular range. The PNLC cell either transmits or scatters the light emerging from the optical film. Experiment using a 15μm-thick PNLC cell shows that the angular distribution becomes 2.3 times wider by turning off the PNLC cell. We place this light source at one end of a light-guide so that the angular distribution of the light propagating inside is controlled. The second key component is some types of micro-strucrures built on the light-guide to out-couple the propagating light. We first attached various optical films on a light-guide surface. Although the angular distribution of the extracted light was switched successfully, light was mostly emitted into an oblique direction, approximately 60° from the plane normal. Next, we used a half-cylinder in place of the optical films. The curved surface of the cylinder was attached to the light-guide with a small amount of matching oil, which constituted an optical window. We measured that the angular distribution of the extracted light decreased to 35° FWHM from 62° FWHM by turning on the PNLC cell.

Colour and Light Effects on Students' Achievement, Behavior and Physiology.

ERIC Educational Resources Information Center

Wohlfarth, H.

A quasi-experimental non-equivalent control group design was used to investigate the effects of full-spectrum light, prescribed color and light/color combinations, ultra-violet light, and electromagnetic radiation in an elementary school environment. Four schools in the Wetaskiwin School District, Alberta, were involved in the study; three served…

Interface Control Document for the Traffic Lights and Emergency Communications System at Gretna and Governor Nicholls Traffic Light Facilities

DOT National Transportation Integrated Search

1997-11-06

Gretna and Governor Nicholls Light facilities are two manned shore side : facilities mounted in critical areas on the banks of the Mississippi River in : the port of New Orleans, Louisiana. Coast Guard plans call for the lights to : be remotely contr...

EFFECT OF AMBIENT LIGHT, AERIAL EXPOSURE, AND SEASON ON EELGRASS (ZOSTERA MARINA) METRICS IN A NORTHEAST PACIFIC (USA) ESTUARY

EPA Science Inventory

Although light is the principal factor controlling the lower depth limit of seagrasses, little attention has been given to how reduced winter lighting may affect intertidal plants. In the present study intertidal light intensity, temperature, and aerial exposure were measured ove...

LED Lighting in a Performing Arts Building

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, N. J.; Kaye, S. M.; Coleman, P. M.

At the University of Florida in Gainesville, the DOE Solid-State Lighting GATEWAY program evaluated LED architectural and theatrical lighting in four academic/performance-related spaces within the Nadine McGuire Theatre + Dance Pavilion. Due to a wise choice of products and luminaire light distributions, the change brought significant quality improvements including improved controllability and color.

Measuring light in uneven-aged hardwood stands

Treesearch

Leon S. Minckler

1961-01-01

Light, essential in the development of a forest, can be controlled within a stand by silvicultural practices. Measuring it, however, has always been a problem for silvicultural researchers. And accurate measurements are necessary, especially in studying the relation between light and reproduction. The desired objective is to measure the total visible light in specific...

Controlling slow and fast light and dynamic pulse-splitting with tunable optical gain in a whispering-gallery-mode microcavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asano, M.; Ikuta, R.; Imoto, N.

We report controllable manipulation of slow and fast light in a whispering-gallery-mode microtoroid resonator fabricated from Erbium (Er{sup 3+}) doped silica. We observe continuous transition of the coupling between the fiber-taper waveguide and the microresonator from undercoupling to critical coupling and then to overcoupling regimes by increasing the pump power even though the spatial distance between the resonator and the waveguide was kept fixed. This, in turn, enables switching from fast to slow light and vice versa just by increasing the optical gain. An enhancement of delay of two-fold over the passive silica resonator (no optical gain) was observed inmore » the slow light regime. Moreover, we show dynamic pulse splitting and its control in slow/fast light systems using optical gain.« less

Suppression of melatonin secretion by bright light in seasonal affective disorder.

PubMed

Partonen, T; Vakkuri, O; Lönnqvist, J

1997-09-15

Eleven patients with winter seasonal affective disorder and 10 healthy controls were exposed to light of 3300 lux for 5 min and for 1 hour respectively on consecutive evenings at 22:00 hours during winter and summer. In the winter, the measurements were undertaken both before and after the treatment with bright light for 2 weeks. In the summer, there was no treatment. Melatonin concentration in saliva and subjective sleepiness were measured at 22:00 and 23:00 hours on each test. There was no significant difference in the suppression of melatonin in response to the light tests between the patients and the controls. Exposure to light reduced the level of subjective sleepiness more among the patients compared to the control subjects. This reduction was not associated with the change in melatonin secretion nor the improvement in depressive symptoms.

In Situ Formation of an Azo Bridge on Proteins Controllable by Visible Light.

PubMed

Hoppmann, Christian; Maslennikov, Innokentiy; Choe, Senyon; Wang, Lei

2015-09-09

Optical modulation of proteins provides superior spatiotemporal resolution for understanding biological processes, and photoswitches built on light-sensitive proteins have been significantly advancing neuronal and cellular studies. Small molecule photoswitches could complement protein-based switches by mitigating potential interference and affording high specificity for modulation sites. However, genetic encodability and responsiveness to nonultraviolet light, two desired properties possessed by protein photoswitches, are challenging to be engineered into small molecule photoswitches. Here we developed a small molecule photoswitch that can be genetically installed onto proteins in situ and controlled by visible light. A pentafluoro azobenzene-based photoswitchable click amino acid (F-PSCaa) was designed to isomerize in response to visible light. After genetic incorporation into proteins via the expansion of the genetic code, F-PSCaa reacts with a nearby cysteine within the protein generating an azo bridge in situ. The resultant bridge is switchable by visible light and allows conformation and binding of CaM to be regulated by such light. This photoswitch should prove valuable in optobiology for its minimal interference, site flexibility, genetic encodability, and response to the more biocompatible visible light.

Ellipsoidal cell flow system

DOEpatents

Salzman, Gary C.; Mullaney, Paul F.

1976-01-01

The disclosure relates to a system incorporating an ellipsoidal flow chamber having light reflective walls for low level light detection in practicing cellular analysis. The system increases signal-to-noise ratio by a factor of ten over prior art systems. In operation, laser light passes through the primary focus of the ellipsoid. A controlled flow of cells simultaneously passes through this focus so that the laser light impinges on the cells and is modulated by the cells. The reflective walls of the ellipsoid reflect the cell-modulated light to the secondary focus of the ellipsoid. A tapered light guide at the secondary focus picks up a substantial portion of modulated reflective light and directs it onto a light detector to produce a signal. The signal is processed to obtain the intensity distribution of the modulated light and hence sought after characteristics of the cells. In addition, cells may be dyed so as to fluoresce in response to the laser light and their fluorescence may be processed as cell-modulated light above described. A light discriminating filter would be used to distinguish reflected modulated laser light from reflected fluorescent light.

Aerosol mass spectrometry systems and methods

DOEpatents

Fergenson, David P.; Gard, Eric E.

2013-08-20

A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

Justification of Natural Lighting Management for Workplaces with Displays

NASA Astrophysics Data System (ADS)

Kudryashov, A. V.; Erunova, A. V.; Kalinina, A. S.

2017-11-01

The article is devoted to the study of the influence of the orientation of light apertures (windows) on the distribution of illumination in a room inside the workplaces equipped with displays. The measurements of natural light were carried out in two similar rooms, in the first room the windows are oriented to the north and in the second - to the south. The normative illumination value in a workplace equipped with a personal computer or display must be between 300 and 500 lux. However, during the daytime, the value of natural illumination at the workplace can exceed the normalized value by several times, and in the morning and evening hours is not sufficient. Such distribution of illumination involves the use a combined lighting control system (with daylight time control and switching on artificial lighting in the morning and evening hours). In the article it is justified that the orientation of the windows in the room does not have a significant effect on the distribution of illumination throughout the room which makes it possible not to take into account the restrictions concerning the orientation of the room’s light apertures when combined lighting control systems are used.

Hyperspectral Image-Based Night-Time Vehicle Light Detection Using Spectral Normalization and Distance Mapper for Intelligent Headlight Control

PubMed Central

Kim, Heekang; Kwon, Soon; Kim, Sungho

2016-01-01

This paper proposes a vehicle light detection method using a hyperspectral camera instead of a Charge-Coupled Device (CCD) or Complementary metal-Oxide-Semiconductor (CMOS) camera for adaptive car headlamp control. To apply Intelligent Headlight Control (IHC), the vehicle headlights need to be detected. Headlights are comprised from a variety of lighting sources, such as Light Emitting Diodes (LEDs), High-intensity discharge (HID), and halogen lamps. In addition, rear lamps are made of LED and halogen lamp. This paper refers to the recent research in IHC. Some problems exist in the detection of headlights, such as erroneous detection of street lights or sign lights and the reflection plate of ego-car from CCD or CMOS images. To solve these problems, this study uses hyperspectral images because they have hundreds of bands and provide more information than a CCD or CMOS camera. Recent methods to detect headlights used the Spectral Angle Mapper (SAM), Spectral Correlation Mapper (SCM), and Euclidean Distance Mapper (EDM). The experimental results highlight the feasibility of the proposed method in three types of lights (LED, HID, and halogen). PMID:27399720

In-ovo green light photostimulation during different embryonic stages affect somatotropic axis.

PubMed

Dishon, L; Avital-Cohen, N; Zaguri, S; Bartman, J; Heiblum, R; Druyan, S; Porter, T E; Gumulka, M; Rozenboim, I

2018-06-01

Previous studies demonstrated that in-ovo photostimulation with monochromatic green light increased the somatotropic axis expression in broilers embryos. The objective of the current study was to detect the critical period for in-ovo GL photostimulation, in order to find the optimal targeted photostimulation period during the incubation process. Three hundred thirty-six fertile broiler eggs were divided into 4 groups. The first group was incubated under dark conditions as a negative control. The second incubated under intermittent monochromatic green light using light-emitting diode (LED) lamps with an intensity of 0.1 W\\m2 at shell level from d 0 of the incubation as a positive control. The third group incubated under intermittent monochromatic green light from d 10 of the incubation. The last group incubated under intermittent monochromatic green light from d 15 of the incubation. In-ovo green light photostimulation from embryonic d 0 (ED0) increased plasma growth hormone (GH), as well as hypothalamic growth hormone releasing hormone (GHRH) and liver growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF-1) mRNA levels. In-ovo green light photostimulation from ED10 increased the GH plasma levels compared to the negative control group, without affecting somatotropic axis mRNA genes expressions of GHRH, GHR, and IGF-1. In-ovo green light photostimulation from ED15 caused an increase in both the plasma GH levels and the somatotropic axis mRNA genes expressions of GHRH, GHR, and IGF-1, compared to the negative control group. These results suggest that the critical period of somatotropic axis acceleration by GL photostimulation start at 15 d of incubation.

Melanopsin Phototransduction Contributes to Light-Evoked Choroidal Expansion and Rod L-Type Calcium Channel Function In Vivo.

PubMed

Berkowitz, Bruce A; Schmidt, Tiffany; Podolsky, Robert H; Roberts, Robin

2016-10-01

In humans, rodents, and pigeons, the dark → light transition signals nonretinal brain tissue to increase choroidal thickness, a major control element of choroidal blood flow, and thus of photoreceptor and retinal pigment epithelium function. However, it is unclear which photopigments in the retina relay the light signal to the brain. Here, we test the hypothesis that melanopsin (Opn4)-regulated phototransduction modulates light-evoked choroidal thickness expansion in mice. Two-month-old C57Bl/6 wild-type (B6), 4- to 5-month-old C57Bl/6/129S6 wild-type (B6 + S6), and 2-month-old melanopsin knockout (Opn4-/-) on a B6 + S6 background were studied. Retinal anatomy was evaluated in vivo by optical coherence tomography and MRI. Choroidal thickness in dark and light were measured by diffusion-weighted MRI. Rod cell L-type calcium channel (LTCC) function in dark and light (manganese-enhanced MRI [MEMRI]) was also measured. Opn4-/- mice did not show the light-evoked expansion of choroidal thickness observed in B6 and B6 + S6 controls. Additionally, Opn4-/- mice had lower than normal rod cell and inner retinal LTCC function in the dark but not in the light. These deficits were not due to structural abnormalities because retinal laminar architecture and thickness, and choroidal thickness in the Opn4-/- mice were similar to controls. First time evidence is provided that melanopsin phototransduction contributes to dark → light control of murine choroidal thickness. The data also highlight a contribution in vivo of melanopsin phototransduction to rod cell and inner retinal depolarization in the dark.

Thermoresponsive scattering coating for smart white LEDs.

PubMed

Bauer, Jurica; Verbunt, Paul P C; Lin, Wan-Yu; Han, Yang; Van, My-Phung; Cornelissen, Hugo J; Yu, Joan J H; Bastiaansen, Cees W M; Broer, Dirk J

2014-12-15

White light emitting diode (LED) systems, capable of lowering the color temperature of emitted light on dimming, have been reported in the literature. These systems all use multiple color LEDs and complex control circuitry. Here we present a novel responsive lighting system based on a single white light emitting LED and a thermoresponsive scattering coating. The coated LED automatically emits light of lower correlated color temperature (CCT) when the power is reduced. We also present results on the use of multiple phosphors in the white light LED allowing for the emission of warm white light in the range between 2900 K and 4150 K, and with a chromaticity complying with the ANSI standards (C78.377). This responsive warm white light LED-system with close-to-ideal emission characteristics is highly interesting for the lighting industry.

One-Pot Synthesis of Multifunctional Polymers by Light-Controlled Radical Polymerization and Enzymatic Catalysis with Candida antarctica Lipase B.

PubMed

Hrsic, Emin; Keul, Helmut; Möller, Martin

2015-12-01

The preparation of multifunctional polymers and block copolymers by a straightforward one-pot reaction process that combines enzymatic transacylation with light-controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light-controlled polymerization, leading to multifunctional methacrylate-based polymers with well-defined microstructure. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Smart Mirrors for Photorefractive Control of Light with Tim Bunning, RX - Agile Filters Application

DTIC Science & Technology

2016-11-08

AFRL-AFOSR-UK-TR-2017-0008 Smart Mirrors for photorefractive control of light with Tim Bunning, RX-- Agile filters application Luciano De Sio...photorefractive control of light with Tim Bunning, RX-- Agile filters application 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-14-1-0050 5c.  PROGRAM...photorefractive, switchable optical filters , liquide crystalline composite materials, Switchable reflective holographic gratings, polymer-dispersed liquid

Direct measurement of light waves.

PubMed

Goulielmakis, E; Uiberacker, M; Kienberger, R; Baltuska, A; Yakovlev, V; Scrinzi, A; Westerwalbesloh, Th; Kleineberg, U; Heinzmann, U; Drescher, M; Krausz, F

2004-08-27

The electromagnetic field of visible light performs approximately 10(15) oscillations per second. Although many instruments are sensitive to the amplitude and frequency (or wavelength) of these oscillations, they cannot access the light field itself. We directly observed how the field built up and disappeared in a short, few-cycle pulse of visible laser light by probing the variation of the field strength with a 250-attosecond electron burst. Our apparatus allows complete characterization of few-cycle waves of visible, ultraviolet, and/or infrared light, thereby providing the possibility for controlled and reproducible synthesis of ultrabroadband light waveforms.

Advanced Solid State Lighting for Human Evaluation Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Holbert, Eirik

2015-01-01

Lighting intensity and color have a significant impact on human circadian rhythms. Advanced solid state lighting was developed for the Advanced Exploration System (AES) Deep Space Habitat(DSH) concept demonstrator. The latest generation of assemblies using the latest commercially available LED lights were designed for use in the Bigelow Aerospace Environmental Control and Life Support System (ECLSS) simulator and the University of Hawaii's Hawaii Space Exploration Analog and Simulation (Hi-SEAS) habitat. Agreements with both these organizations will allow the government to receive feedback on the lights and lighting algorithms from long term human interaction.

Influence of pre-harvest red light irradiation on main phytochemicals and antioxidant activity of Chinese kale sprouts.

PubMed

Deng, Mingdan; Qian, Hongmei; Chen, Lili; Sun, Bo; Chang, Jiaqi; Miao, Huiying; Cai, Congxi; Wang, Qiaomei

2017-05-01

The effects of pre-harvest red light irradiation on main healthy phytochemicals as well as antioxidant activity of Chinese kale sprouts during postharvest storage were investigated. 6-day-old sprouts were treated by red light for 24h before harvest and sampled for further analysis of nutritional quality on the first, second and third day after harvest. The results indicated that red light exposure notably postponed the degradation of aliphatic, indole, and total glucosinolates during postharvest storage. The vitamin C level was remarkably higher in red light treated sprouts on the first and second day after harvest when compared with the control. In addition, red light treatment also enhanced the accumulation of total phenolics and maintained higher level of antioxidant activity than the control. All above results suggested that pre-harvest red light treatment might provide a new strategy to maintain the nutritive value of Chinese kale sprouts during postharvest storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

A nitric oxide concentration clamp.

PubMed

Zhelyaskov, V R; Godwin, D W

1999-10-01

We report a new method of generating nitric oxide (NO) that possesses several advantages for experimental use. This method consists of a photolysis chamber where NO is released by illuminating photolabile NO donors with light from a xenon lamp, in conjunction with feedback control. Control of the photolysis light was achieved by selectively gating light projected through a shutter before the light was launched into a light guide that conveyed the light to the photolysis chamber. By gating the light in proportion to a sensor that reported nearly instantaneous concentration from the photolysis chamber, a criterion NO concentration could be achieved, which could be easily adjusted to higher or lower criterion levels. To denote the similarity of this process with the electrophysiological process of voltage clamp, we term this process a concentration "clamp." This development enhances the use of the fiber-optic-based system for NO delivery and should enable the execution of experiments where the in situ concentration of NO is particularly critical, such as in biological preparations. Copyright 1999 Academic Press.

A sensor-less LED dimming system based on daylight harvesting with BIPV systems.

PubMed

Yoo, Seunghwan; Kim, Jonghun; Jang, Cheol-Yong; Jeong, Hakgeun

2014-01-13

Artificial lighting in office buildings typically requires 30% of the total energy consumption of the building, providing a substantial opportunity for energy savings. To reduce the energy consumed by indoor lighting, we propose a sensor-less light-emitting diode (LED) dimming system using daylight harvesting. In this study, we used light simulation software to quantify and visualize daylight, and analyzed the correlation between photovoltaic (PV) power generation and indoor illumination in an office with an integrated PV system. In addition, we calculated the distribution of daylight illumination into the office and dimming ratios for the individual control of LED lights. Also, we were able directly to use the electric power generated by PV system. As a result, power consumption for electric lighting was reduced by 40 - 70% depending on the season and the weather conditions. Thus, the dimming system proposed in this study can be used to control electric lighting to reduce energy use cost-effectively and simply.

Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

PubMed

Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

2015-04-14

This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

Solid state light source driver establishing buck or boost operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, Fred

A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boostmore » converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.« less

Electrical tuning of the polarization state of light using graphene-integrated anisotropic metasurfaces

NASA Astrophysics Data System (ADS)

Dutta-Gupta, Shourya; Dabidian, Nima; Kholmanov, Iskandar; Belkin, Mikhail A.; Shvets, Gennady

2017-03-01

Plasmonic metasurfaces have been employed for moulding the flow of transmitted and reflected light, thereby enabling numerous applications that benefit from their ultra-thin sub-wavelength format. Their appeal is further enhanced by the incorporation of active electro-optic elements, paving the way for dynamic control of light's properties. In this paper, we realize a dynamic polarization state generator using a graphene-integrated anisotropic metasurface (GIAM) that converts the linear polarization of the incident light into an elliptical one. This is accomplished by using an anisotropic metasurface with two principal polarization axes, one of which possesses a Fano-type resonance. A gate-controlled single-layer graphene integrated with the metasurface was employed as an electro-optic element controlling the phase and intensity of light polarized along the resonant axis of the GIAM. When the incident light is polarized at an angle to the resonant axis of the metasurface, the ellipticity of the reflected light can be dynamically controlled by the application of a gate voltage. Thus accomplished dynamic polarization control is experimentally demonstrated and characterized by measuring the Stokes polarization parameters. Large changes of the ellipticity and the tilt angle of the polarization ellipse are observed. Our measurements show that the tilt angle can be changed from positive values through zero to negative values while keeping the ellipticity constant, potentially paving the way to rapid ellipsometry and other characterization techniques requiring fast polarization shifting. This article is part of the themed issue 'New horizons for nanophotonics'.

Low light intensity effects on the growth, photosynthetic characteristics, antioxidant capacity, yield and quality of wheat (Triticum aestivum L.) at different growth stages in BLSS

NASA Astrophysics Data System (ADS)

Dong, Chen; Fu, Yuming; Liu, Guanghui; Liu, Hong

2014-06-01

Minimizing energy consumption and maximizing crop productivity are major challenges to growing plants in Bioregenerative Life Support System (BLSS) for future long-term space mission. As a primary source of energy, light is one of the most important environmental factors for plant growth. The purpose of this study is to investigate the effects of low light intensity at different stages on growth, pigment composition, photosynthetic efficiency, biological production and antioxidant defence systems of wheat (Triticum aestivum L.) cultivars during ontogenesis. Experiments were divided into 3 intensity-controlled stages according to growth period (a total of 65 days): seedling stage (first 20 days), heading and flowering stage (middle 30 days) and grain filling stage (last 15 days). Initial light condition of the control was 420 μmol m-2 s-1 and the light intensity increased with the growth of wheat plants. The light intensities of group I and II at the first stage and the last stage were adjusted to the half level of the control respectively. For group III, the first and the last stage were both adjusted to half level of the control. During the middle 30 days, all treatments were kept the same intensity. The results indicated that low-light treatment at seedling stage, biomass, nutritional contents, components of inedible biomass and healthy index (including peroxidase (POD) activity, malondialdehyde (MDA) and proline content) of wheat plants have no significant difference to the control. Furthermore, unit kilojoule yield of group I reached 0.591 × 10-3 g/kJ and induced the highest energy efficiency. However, low-light treatment at grain filling stage affected the final production significantly.

Orbital experiment ``Gravisensor'': phototropic reactions of the moss Physcomitrella patens to different types of LED lighting.

NASA Astrophysics Data System (ADS)

Nikitin, Vladimir; Berkovich, Yuliy A.; Skripnikov, Alexander; Zyablova, Natalya; Mukhoyan, Makar; Emelianov, Grigory

The experiment was conducted on Russian Biological Satelite Bion-M #1 19.04-19.05 2013. Five transparent plastic cultural flasks were placed in five light isolated sections of Biocont-B2 cylindrical container with inner diameter of 120 mm and height of 230 mm. In four sections the flasks could be illuminated by top or side LED with wavelength of 458 nm, 630 nm, 730 nm, and white (color temperature 5000° K, peaks 453, 559 nm). Photon flux in each variant was 15 umol/(m2c). In the fifth section the flask with the shoots was in conditions of constant dark. Each section was equipped with its own video camera module. Cameras, video recorder and lighting were managed by micro controller. 12 days before launch, 5 tips of the moss shoots were explanted at each of the five flasks on the agar medium with nutrient components and were cultivated under white fluorescent lamps at 12 hour photo period till the launch. After entering the orbit and during next 14 days of flight top LEDs were turned on above the flasks. Then for the following 14 days of flight the side LEDs of similar wavelength were turned on. The moss gametophores were cultivated at 12-h photoperiod. During the experiment on an hourly basis a video recording of the moss was performed. Similar equipment was used for ground control. After the experiment video files were used to produce separate time-lapse films for each flask using AviSynth program. In flight the shoots demonstrated the maximum growth speed with far red lighting and slower speed with white lighting. With blue and red lighting after switching to side light stimuli the growth of shoots almost stopped. In the dark the shoots continued to grow until the 13 day after launch of the satellite, then their growth stopped. In ground control the relation of growth rate with various LEDs remained basically the same, with the exception of side blue lighting, where the shoots demonstrated considerable vertical growth. In flight the angle of inclination towards the light source was maximal (about 90º) with white lighting, and somewhat smaller with 730 nm. Under red and blue light the angle of phototropic inclination was difficult to measure due to poor growth of the shoots.In ground control the growth rate under blue light was several times higher, than in flight and final degree of inclination of the shoot tip came to about 10º. In ground control under side red lighting the growth was weak, while demonstrating a pronounced phototropic bend of 90º. In ground control in the dark a vertical growth of one shoot was observed with the rate somewhat larger, than in flight variant. Data on the dynamics of inclination of experimental and control plants are presented. The acquired data will be used to analyse the mechanisms of phototropic growth changes of moss shoots.

Application of 3D printing to prototype and develop novel plant tissue culture systems.

PubMed

Shukla, Mukund R; Singh, Amritpal S; Piunno, Kevin; Saxena, Praveen K; Jones, A Maxwell P

2017-01-01

Due to the complex process of designing and manufacturing new plant tissue culture vessels through conventional means there have been limited efforts to innovate improved designs. Further, development and availability of low cost, energy efficient LEDs of various spectra has made it a promising light source for plant growth in controlled environments. However, direct replacement of conventional lighting sources with LEDs does not address problems with uniformity, spectral control, or the challenges in conducting statistically valid experiments to assess the effects of light. Prototyping using 3D printing and LED based light sources could help overcome these limitations and lead to improved culture systems. A modular culture vessel design in which the fluence rate and spectrum of light are independently controlled was designed, prototyped using 3D printing, and evaluated for plant growth. This design is compatible with semi-solid and liquid based culture systems. Observations on morphology, chlorophyll content, and chlorophyll fluorescence based stress parameters from in vitro plants cultured under different light spectra with similar overall fluence rate indicated different responses in Nicotiana tabacum and Artemisia annua plantlets. This experiment validates the utility of 3D printing to design and test functional vessels and demonstrated that optimal light spectra for in vitro plant growth is species-specific. 3D printing was successfully used to prototype novel culture vessels with independently controlled variable fluence rate/spectra LED lighting. This system addresses several limitations associated with current lighting systems, providing more uniform lighting and allowing proper replication/randomization for experimental plant biology while increasing energy efficiency. A complete procedure including the design and prototyping of a culture vessel using 3D printing, commercial scale injection molding of the prototype, and conducting a properly replicated experiment are discussed. This open source design has the scope for further improvement and adaptation and demonstrates the power of 3D printing to improve the design of culture systems.

A field demonstration of energy conservation using occupancy sensor lighting control in equipment rooms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagle, J.E.

1992-09-01

The Pacific Northwest Laboratory identified energy savings potential of automatic equipment-room lighting controls, which was demonstrated by the field experiment described in this report. Occupancy sensor applications have gained popularity in recent years due to improved technology that enhances reliability and reduces cost. Automatic lighting control using occupancy sensors has been accepted as an energy-conservation measure because it reduces wasted lighting. This study focused on lighting control for equipment rooms, which have inherent conditions ideal for automatic lighting control, i.e., an area which is seldom occupied, multiple users of the area who would not know if others are in themore » room when they leave, and high lighting energy intensity in the area. Two rooms were selected for this study: a small equipment room in the basement of the 337 Building, and a large equipment area in the upper level of the 329 Building. The rooms were selected to demonstrate the various degrees of complexity which may be encountered in equipment rooms throughout the Hanford Site. The 337 Building equipment-room test case demonstrated a 97% reduction in lighting energy consumption, with an annual energy savings of $184. Including lamp-replacement savings, a total savings of $306 per year is offset by an initial installation cost of $1,100. The installation demonstrates a positive net present value of $2,858 when the lamp-replacement costs are included in a life-cycle analysis. This also corresponds to a 4.0-year payback period. The 329 Building equipment-room installation resulted in a 92% reduction in lighting energy consumption. This corresponds to annual energy savings of $1,372, and a total annual savings of $2,104 per year including lamp-replacement savings. The life-cycle cost analysis shows a net present value of $15,855, with a 5.8-year payback period.« less

Focusing light through strongly scattering media by controlling binary amplitude optimization using genetic algorithm

NASA Astrophysics Data System (ADS)

Liu, Zhipeng; Zhang, Bin; Feng, Qi; Chen, Zhaoyang; Lin, Chengyou; Ding, Yingchun

2017-06-01

Focusing light through strongly scattering media plays an important role in biomedical imaging and therapy. Here, we experimentally demonstrate light focusing through ZnO sample by controlling binary amplitude optimization using genetic algorithm. In the experiment, we use a Micro Electro-Mechanical System (MEMS)-based digital micromirror device (DMD) which is in amplitude-only modulation mode. The DMD consists of 1920×1080 square mirrors that can be independently controlled to reflect light to a desired position. We control only 160 thousand mirrors which are divided into 400 segments to modulate light focusing through the scattering media using advanced genetic algorithm. Light intensity at the target position is enhanced up to 50+/-5 times the average speckle intensity. The diameters of focusing spot can be changed ranging from 7 μm to 70 μm at arbitrary positions and multiple foci are obtained simultaneously. The spatial arrangement of multiple foci can be flexibly controlled. The advantage of DMDs lies in their switching speed up to 30 kHz, which has the potential to generate a focus in an ultra-short period of time. Our work provides a reference for the study of high speed wavefront shaping that is required in vivo tissues imaging.

Attosecond control of electronic processes by intense light fields.

PubMed

Baltuska, A; Udem, Th; Uiberacker, M; Hentschel, M; Goulielmakis, E; Gohle, Ch; Holzwarth, R; Yakovlev, V S; Scrinzi, A; Hänsch, T W; Krausz, F

2003-02-06

The amplitude and frequency of laser light can be routinely measured and controlled on a femtosecond (10(-15) s) timescale. However, in pulses comprising just a few wave cycles, the amplitude envelope and carrier frequency are not sufficient to characterize and control laser radiation, because evolution of the light field is also influenced by a shift of the carrier wave with respect to the pulse peak. This so-called carrier-envelope phase has been predicted and observed to affect strong-field phenomena, but random shot-to-shot shifts have prevented the reproducible guiding of atomic processes using the electric field of light. Here we report the generation of intense, few-cycle laser pulses with a stable carrier envelope phase that permit the triggering and steering of microscopic motion with an ultimate precision limited only by quantum mechanical uncertainty. Using these reproducible light waveforms, we create light-induced atomic currents in ionized matter; the motion of the electronic wave packets can be controlled on timescales shorter than 250 attoseconds (250 x 10(-18) s). This enables us to control the attosecond temporal structure of coherent soft X-ray emission produced by the atomic currents--these X-ray photons provide a sensitive and intuitive tool for determining the carrier-envelope phase.

Light Emitting Diodes and Astronomical Environments: Results from in situ Field Measurements

NASA Astrophysics Data System (ADS)

Craine, Brian L.; Craine, Eric R.

2015-05-01

Light emitting diode (LED) light fixtures are rapidly becoming industry standards for outdoor lighting. They are promoted on the strength of long lifetimes (hence economic efficiencies), low power requirements, directability, active brightness controls, and energy efficiency. They also tend to produce spectral shifts that are undesirable in astronomical settings, but which can be moderated by filters. LED lighting for continuous roadway and parking lot lighting is particularly popular, and many communities are in the process of retrofitting Low Pressure Sodium (LPS) and other lights by tens of thousands of new LED fixtures at a time. What is the impact of this process on astronomical observatories and on dark skies upon which amateur astronomers rely? We bypass modeling and predictions to make actual measurements of these lights in the field. We report on original ground, airborne, and satellite observations of LED lights and discuss their light budgets, zenith angle functions, and impacts on observatory environs.

Lighting Automation - Flying an Earthlike Habit Project

NASA Technical Reports Server (NTRS)

Falker, Jay; Howard, Ricky; Culbert, Christopher; Clark, Toni Anne; Kolomenski, Andrei

2017-01-01

Our proposal will enable the development of automated spacecraft habitats for long duration missions. Majority of spacecraft lighting systems employ lamps or zone specific switches and dimmers. Automation is not in the "picture". If we are to build long duration environments, which provide earth-like habitats, minimize crew time, and optimize spacecraft power reserves, innovation in lighting automation is a must. To transform how spacecraft lighting environments are automated, we will provide performance data on a standard lighting communication protocol. We will investigate utilization and application of an industry accepted lighting control protocol, DMX512. We will demonstrate how lighting automation can conserve power, assist with lighting countermeasures, and utilize spatial body tracking. By using DMX512 we will prove the "wheel" does not need to be reinvented in terms of smart lighting and future spacecraft can use a standard lighting protocol to produce an effective, optimized and potentially earthlike habitat.

Effect of Light on Anthocyanin Levels in Submerged, Harvested Cranberry Fruit

PubMed Central

Singh, Bal Ram

2004-01-01

Anthocyanins are a group of plant antioxidants known for their therapeutic use. The effects of natural light, red light, and far-red light on individual as well as total anthocyanin content in cranberry fruit (Vaccinium macrocarpon Ait) were examined in an experimental setting designed to mimic water-harvesting conditions. The reversed-phase high-performance liquid chromatography (HPLC) method was used to separate and analyze the anthocyanins. In contrast to the case of the control sample that was kept in the dark, natural light increased the total anthocyanin level by 75.3% and 87.2% after 24 and 48 hours of water immersion, respectively. Red light and far-red light increased the total anthocyanin level by 41.5% and 34.7%, respectively. The amount of each individual anthocyanin increased differently under natural light, red light, and far-red light, suggesting that expressions of enzymes that catalyze the anthocyanin biosynthesis are regulated differently by environments. PMID:15577187

Approaches to Study Light Effects on Brassinosteroid Sensitivity.

PubMed

Paulišić, Sandi; Molina-Contreras, Maria José; Roig-Villanova, Irma; Martínez-García, Jaime F

2017-01-01

Light perception and hormone signaling in plants are likely connected at multiple points. Light conditions, perceived by photoreceptors, control plant responses by altering hormone concentration, tissue sensitivity, or a combination of both. Whereas it is relatively straightforward to assess the light effects on hormone levels, hormone sensitivity is subjected to interpretation. In Arabidopsis thaliana seedlings, hypocotyl length is strongly affected by light conditions. As hypocotyl elongation also depends on brassinosteroids (BRs), assaying this response provides a valuable and easy way to measure the responsiveness of seedlings to BRs and the impact of light. We describe a simple protocol to evaluate the responsiveness of hypocotyls to commercial BRs and/or BR inhibitors under a range of light conditions. These assays can be used to establish whether light affects BR sensitivity or whether BRs affect light sensitivity. Overall, our protocol can be easily applied for deetiolation (under polychromatic or monochromatic light) and simulated shade treatments combined with BR treatments.

Indocyanine Green-Loaded Liposomes for Light-Triggered Drug Release.

PubMed

Lajunen, Tatu; Kontturi, Leena-Stiina; Viitala, Lauri; Manna, Moutusi; Cramariuc, Oana; Róg, Tomasz; Bunker, Alex; Laaksonen, Timo; Viitala, Tapani; Murtomäki, Lasse; Urtti, Arto

2016-06-06

Light-triggered drug delivery systems enable site-specific and time-controlled drug release. In previous work, we have achieved this with liposomes containing gold nanoparticles in the aqueous core. Gold nanoparticles absorb near-infrared light and release the energy as heat that increases the permeability of the liposomal bilayer, thus releasing the contents of the liposome. In this work, we replaced the gold nanoparticles with the clinically approved imaging agent indocyanine green (ICG). The ICG liposomes were stable at storage conditions (4-22 °C) and at body temperature, and fast near-infrared (IR) light-triggered drug release was achieved with optimized phospholipid composition and a 1:50 ICG-to-lipid molar ratio. Encapsulated small molecular calcein and FITC-dextran (up to 20 kDa) were completely released from the liposomes after light exposure for 15 s. Location of ICG in the PEG layer of the liposomes was simulated with molecular dynamics. ICG has important benefits as a light-triggering agent in liposomes: fast content release, improved stability, improved possibility of liposomal size control, regulatory approval to use in humans, and the possibility of imaging the in vivo location of the liposomes based on the fluorescence of ICG. Near-infrared light used as a triggering mechanism has good tissue penetration and safety. Thus, ICG liposomes are an attractive option for light-controlled and efficient delivery of small and large drug molecules.

Light emission mechanism of mixed host organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Song, Wook; Lee, Jun Yeob

2015-03-01

Light emission mechanism of organic light-emitting diodes with a mixed host emitting layer was studied using an exciplex type mixed host and an exciplex free mixed host. Monitoring of the current density and luminance of the two type mixed host devices revealed that the light emission process of the exciplex type mixed host was dominated by energy transfer, while the light emission of the exciplex free mixed host was controlled by charge trapping. Mixed host composition was also critical to the light emission mechanism, and the contribution of the energy transfer process was maximized at 50:50 mixed host composition. Therefore, it was possible to manage the light emission process of the mixed host devices by managing the mixed host composition.

A Green-Light-Responsive System for the Control of Transgene Expression in Mammalian and Plant Cells.

PubMed

Chatelle, Claire; Ochoa-Fernandez, Rocio; Engesser, Raphael; Schneider, Nils; Beyer, Hannes M; Jones, Alex R; Timmer, Jens; Zurbriggen, Matias D; Weber, Wilfried

2018-05-18

The ever-increasing complexity of synthetic gene networks and applications of synthetic biology requires precise and orthogonal gene expression systems. Of particular interest are systems responsive to light as they enable the control of gene expression dynamics with unprecedented resolution in space and time. While broadly used in mammalian backgrounds, however, optogenetic approaches in plant cells are still limited due to interference of the activating light with endogenous photoreceptors. Here, we describe the development of the first synthetic light-responsive system for the targeted control of gene expression in mammalian and plant cells that responds to the green range of the light spectrum in which plant photoreceptors have minimal activity. We first engineered a system based on the light-sensitive bacterial transcription factor CarH and its cognate DNA operator sequence CarO from Thermus thermophilus to control gene expression in mammalian cells. The system was functional in various mammalian cell lines, showing high induction (up to 350-fold) along with low leakiness, as well as high reversibility. We quantitatively described the systems characteristics by the development and experimental validation of a mathematical model. Finally, we transferred the system into A. thaliana protoplasts and demonstrated gene repression in response to green light. We expect that this system will provide new opportunities in applications based on synthetic gene networks and will open up perspectives for optogenetic studies in mammalian and plant cells.

"Crypto-Display" in Dual-Mode Metasurfaces by Simultaneous Control of Phase and Spectral Responses.

PubMed

Yoon, Gwanho; Lee, Dasol; Nam, Ki Tae; Rho, Junsuk

2018-06-26

Although conventional metasurfaces have demonstrated many promising functionalities in light control by tailoring either phase or spectral responses of subwavelength structures, simultaneous control of both responses has not been explored yet. Here, we propose a concept of dual-mode metasurfaces that enables simultaneous control of phase and spectral responses for two kinds of operation modes of transmission and reflection, respectively. In the transmission mode, the dual-mode metasurface acts as conventional metasurfaces by tailoring phase distribution of incident light. In the reflection mode, a reflected colored image is produced under white light illumination. We also experimentally demonstrate a crypto-display as one application of the dual-mode metasurface. The crypto-display looks a normal reflective display under white light illumination but generates a hologram that reveals the encrypted phase information under single-wavelength coherent light illumination. Because two operation modes do not affect each other, the crypto-display can have applications in security techniques.

Wavelength-Selective Light-Responsive DASA-Functionalized Polymersome Nanoreactors.

PubMed

Rifaie-Graham, Omar; Ulrich, Sebastian; Galensowske, Nikolas F B; Balog, Sandor; Chami, Mohamed; Rentsch, Daniel; Hemmer, James R; Read de Alaniz, Javier; Boesel, Luciano F; Bruns, Nico

2018-06-27

Transient activation of biochemical reactions by visible light and subsequent return to the inactive state in the absence of light is an essential feature of the biochemical processes in photoreceptor cells. To mimic such light-responsiveness with artificial nanosystems, polymersome nanoreactors were developed that can be switched on by visible light and self-revert fast in the dark at room temperature to their inactive state. Donor-acceptor Stenhouse adducts (DASAs), with their ability to isomerize upon irradiation with visible light, were employed to change the permeability of polymersome membranes by switching polarity from a nonpolar triene-enol form to a cyclopentenone with increased polarity. To this end, amphiphilic block copolymers containing poly(pentafluorophenyl methacrylate) in their hydrophobic block were synthesized by reversible addition-fragmentation chain-transfer (RAFT) radical polymerization and functionalized either with a DASA that is based on Meldrum's acid or with a novel fast-switching pyrazolone-based DASA. These polymers were self-assembled into vesicles. Release of hydrophilic payload could be triggered by light and stopped as soon as the light was turned off. The encapsulation of enzymes yielded photoresponsive nanoreactors that catalyzed reactions only if they were irradiated with light. A mixture of polymersome nanoreactors, one that switches in green light, the other switching in red light, permitted specific control of the individual reactions of a reaction cascade in one pot by irradiation with varied wavelengths, thus enabling light-controlled wavelength-selective catalysis. The DASA-based nanoreactors demonstrate the potential of DASAs to switch permeability of membranes and could find application to switch reactions on and off, on demand, e.g., in microfluidics or in drug delivery.

Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Yun; Ling, Li; Li, Xiaofang

This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe{sub 3}O{sub 4} nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N{sub 2} adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emissionmore » spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe{sub 3}O{sub 4} core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s.« less

Hydrogels for efficient light delivery in optogenetic applications

NASA Astrophysics Data System (ADS)

Johannsmeier, S.; Torres, M. L.; Ripken, T.; Heinemann, D.; Heisterkamp, A.

2018-02-01

Light-based therapies have been established for various indications, such as skin conditions, cancer or neonatal jaundice. Advances in the field of optogenetics open up new horizons for light-tissue interactions with an organism-wide impact. Excitable tissues, such as nerve and muscle tissues, can be controlled by light after the introduction of light-sensitive ion channels. Since these organs are generally not easily accessible to illumination in vivo, there is an increasing need for effective biocompatible waveguides for light delivery. These devices not only have to guide and distribute the light as desired with minimal losses, they should also mimic the mechanical properties of the surrounding tissue to ensure compatibility. In this project, we are tuning the properties of hydrogels from poly(ethylene glycol) derivatives to achieve compatibility with muscle tissue as well as optimal light guiding and distribution for optogenetic applications at the heart. The excitation light is coupled into the hydrogel with a biocompatible fiber. Properties of the hydrogel are mainly tuned by monomer length and concentration. Total reflection can be achieved by embedding a fiber-like hydrogel with a high refractive index into a second, low refractive index gel. Different geometries and scattering microparticles are used for light distribution in a flat gel patch. Targeted cell attachment can be achieved by introducing a protein layer to the otherwise bioinert gel. After optimization, the hydrogel may be used to deliver light for the excitation of genetically altered cardiomyocytes for controlled contraction.

Bright light therapy decreases winter binge frequency in women with bulimia nervosa: a double-blind, placebo-controlled study.

PubMed

Braun, D L; Sunday, S R; Fornari, V M; Halmi, K A

1999-01-01

The study objective was to determine the effect of winter bright light therapy on binge and purge frequencies and depressive symptoms in subjects with bulimia nervosa. Thirty-four female bulimic outpatients were treated with either 10,000 lux bright white light or 50 lux dim red light (placebo control) during the winter months. In this double-blind study, the placebo group (n = 18) and the bright light group (n = 16) were matched for age, degree of seasonality (measured by the Seasonal Patterns Assessment Questionnaire [SPAQ]), and concurrent depression (measured by Structured Clinical Interview for DSM-IV [SCID]). Three weeks of baseline data collection were followed by 3 weeks of half-hour daily morning light treatment and 2 weeks of follow-up evaluation. There was a significant light-treatment by time interaction (Wilks' lambda = .81, F(2,28) = 3.31, P = .05). The mean binge frequency decreased significantly more from baseline to the end of treatment for the bright light group (F(1,29) = 6.41, P = .017) than for the placebo group. The level of depression (measured by daily Beck Depression Inventory [BDI] scores) did not significantly differ between the groups during any phase, and neither depression nor seasonality affected the response to light treatment. In this double-blind study, bulimic women who received 3 weeks of winter bright light treatment reported a reduced binge frequency between baseline and the active treatment period in comparison to subjects receiving dim red light.

Adult Tea Green Leafhoppers, Empoasca onukii (Matsuda), Change Behaviors under Varying Light Conditions

PubMed Central

Shi, Longqing; Vasseur, Liette; Huang, Huoshui; Zeng, Zhaohua; Hu, Guiping; Liu, Xin; You, Minsheng

2017-01-01

Insect behaviors are often influenced by light conditions including photoperiod, light intensity, and wavelength. Understanding pest insect responses to changing light conditions may help with developing alternative strategies for pest control. Little is known about the behavioral responses of leafhoppers (Hemiptera: Cicadellidae) to light conditions. The behavior of the tea green leafhopper, Empoasca onukii Matsuda, was examined when exposed to different light photoperiods or wavelengths. Observations included the frequency of locomotion and cleaning activities, and the duration of time spent searching. The results suggested that under normal photoperiod both female and male adults were generally more active in darkness (i.e., at night) than in light. In continuous darkness (DD), the locomotion and cleaning events in Period 1 (7:00–19:00) were significantly increased, when compared to the leafhoppers under normal photoperiod (LD). Leafhoppers, especially females, changed their behavioral patterns to a two day cycle under DD. Under continuous illumination (continuous quartz lamp light, yellow light at night, and green light at night), the activities of locomotion, cleaning, and searching were significantly suppressed during the night (19:00–7:00) and locomotion activities of both females and males were significantly increased during the day (7:00–19:00), suggesting a shift in circadian rhythm. Our work suggests that changes in light conditions, including photoperiod and wavelength, can influence behavioral activities of leafhoppers, potentially affecting other life history traits such as reproduction and development, and may serve as a method for leafhopper behavioral control. PMID:28103237

Effect of Dynamic Light Application on Cognitive Performance and Well-being of Intensive Care Nurses.

PubMed

Simons, Koen S; Boeijen, Enzio R K; Mertens, Marlies C; Rood, Paul; de Jager, Cornelis P C; van den Boogaard, Mark

2018-05-01

Exposure to bright light has alerting effects. In nurses, alertness may be decreased because of shift work and high work pressure, potentially reducing work performance and increasing the risk for medical errors. To determine whether high-intensity dynamic light improves cognitive performance, self-reported depressive signs and symptoms, fatigue, alertness, and well-being in intensive care unit nurses. In a single-center crossover study in an intensive care unit of a teaching hospital in the Netherlands, 10 registered nurses were randomly divided into 2 groups. Each group worked alternately for 3 to 4 days in patients' rooms with dynamic light and 3 to 4 days in control lighting settings. High-intensity dynamic light was administered through ceiling-mounted fluorescent tubes that delivered bluish white light up to 1700 lux during the daytime, versus 300 lux in control settings. Cognitive performance, self-reported depressive signs and symptoms, fatigue, and well-being before and after each period were assessed by using validated cognitive tests and questionnaires. Cognitive performance, self-reported depressive signs and symptoms, and fatigue did not differ significantly between the 2 light settings. Scores of subjective well-being were significantly lower after a period of working in dynamic light. Daytime lighting conditions did not affect intensive care unit nurses' cognitive performance, perceived depressive signs and symptoms, or fatigue. Perceived quality of life, predominantly in the psychological and environmental domains, was lower for nurses working in dynamic light. © 2018 American Association of Critical-Care Nurses.

Adult Tea Green Leafhoppers, Empoasca onukii (Matsuda), Change Behaviors under Varying Light Conditions.

PubMed

Shi, Longqing; Vasseur, Liette; Huang, Huoshui; Zeng, Zhaohua; Hu, Guiping; Liu, Xin; You, Minsheng

2017-01-01

Insect behaviors are often influenced by light conditions including photoperiod, light intensity, and wavelength. Understanding pest insect responses to changing light conditions may help with developing alternative strategies for pest control. Little is known about the behavioral responses of leafhoppers (Hemiptera: Cicadellidae) to light conditions. The behavior of the tea green leafhopper, Empoasca onukii Matsuda, was examined when exposed to different light photoperiods or wavelengths. Observations included the frequency of locomotion and cleaning activities, and the duration of time spent searching. The results suggested that under normal photoperiod both female and male adults were generally more active in darkness (i.e., at night) than in light. In continuous darkness (DD), the locomotion and cleaning events in Period 1 (7:00-19:00) were significantly increased, when compared to the leafhoppers under normal photoperiod (LD). Leafhoppers, especially females, changed their behavioral patterns to a two day cycle under DD. Under continuous illumination (continuous quartz lamp light, yellow light at night, and green light at night), the activities of locomotion, cleaning, and searching were significantly suppressed during the night (19:00-7:00) and locomotion activities of both females and males were significantly increased during the day (7:00-19:00), suggesting a shift in circadian rhythm. Our work suggests that changes in light conditions, including photoperiod and wavelength, can influence behavioral activities of leafhoppers, potentially affecting other life history traits such as reproduction and development, and may serve as a method for leafhopper behavioral control.

Partially coherent polarized atmospheric transmission characteristics and application technology research

NASA Astrophysics Data System (ADS)

Fu, Qiang; Gao, Duorui; Liu, Zhi; Chen, Chunyi; Lou, Yan; Jiang, Huilin

2014-11-01

Based on partially coherent polarized light transmission characteristics of the atmosphere, an intensity expression of completely coherent flashing light is derived from Andrews scale modulation method. According to the generalized Huygens-Fresnel principle and Rytov theory, the phase fluctuation structure function is obtained on condition that the refractive index profile in the atmosphere meet Von Karman spectrum, then get the arrival Angle fluctuation variance. Through the RMS beam width of gaussian beams in turbulent atmosphere, deviation angle formula of fully coherent gaussian beams in turbulence atmosphere is attained, then get the RMS beam width of partially coherent and derivation angle expression of GSM beam in turbulent atmosphere. Combined with transmission properties of radial polarized laser beam, cross spectral density matrix of partially coherent radially polarized light can be gained by using generalized huygens-fresnel principle. And light intensity and polarization after transmission can be known according to the unity of coherence and polarization theory. On the basis of the analysis model and numerical simulation, the simulation results show that: the light spot caused by atmospheric turbulence of partially coherent polarization will be superior to completely polarized light.Taking advantage of this feature, designed a new wireless suppression technology of atmospheric turbulence, that is the optimization criterion of initial degree of coherent light beam. The optimal initial degree of coherent light beam will change along with the change of atmospheric turbulence conditions,make control the beam's initial degree of coherence to realize the initial degree of coherence of light beam in real time and dynamic control. A spatial phase screen before emission aperture of fully coherent light is to generate the partially coherent light, liquid crystal spatial light modulator is is a preferable way to realize the dynamic random phase. Finally look future of the application research of partially coherent light.

Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset

PubMed Central

2012-01-01

Background A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band “green” light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep). The second study investigated whether two individual-specific light doses expected to suppress melatonin by 30% and 60% and delivered through subjects’ closed eyelids before the time of their predicted minimum core body temperature would phase delay the timing of their dim light melatonin onset (DLMO). Findings Compared to a dark control night, light delivered through eyelids suppressed melatonin by 36% (p = 0.01) after 60-minute light exposure at the beginning, 45% (p = 0.01) at the middle, and 56% (p < 0.0001) at the end of the night. In the second study, compared to a dark control night, melatonin was suppressed by 25% (p = 0.03) and by 45% (p = 0.009) and circadian phase, as measured by DLMO, was delayed by 17 minutes (p = 0.03) and 71 minutes (ns) after 60-minute exposures to light levels 1 and 2, respectively. Conclusions These studies demonstrate that individual-specific doses of light delivered through closed eyelids can suppress melatonin and phase shift DLMO and may be used to treat circadian sleep disorders. PMID:22564396

Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset.

PubMed

Figueiro, Mariana G; Rea, Mark S

2012-05-07

A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band "green" light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep). The second study investigated whether two individual-specific light doses expected to suppress melatonin by 30% and 60% and delivered through subjects' closed eyelids before the time of their predicted minimum core body temperature would phase delay the timing of their dim light melatonin onset (DLMO). Compared to a dark control night, light delivered through eyelids suppressed melatonin by 36% (p = 0.01) after 60-minute light exposure at the beginning, 45% (p = 0.01) at the middle, and 56% (p < 0.0001) at the end of the night. In the second study, compared to a dark control night, melatonin was suppressed by 25% (p = 0.03) and by 45% (p = 0.009) and circadian phase, as measured by DLMO, was delayed by 17 minutes (p = 0.03) and 71 minutes (ns) after 60-minute exposures to light levels 1 and 2, respectively. These studies demonstrate that individual-specific doses of light delivered through closed eyelids can suppress melatonin and phase shift DLMO and may be used to treat circadian sleep disorders.

Light-controlled inhibition of malignant glioma by opsin gene transfer

PubMed Central

Yang, F; Tu, J; Pan, J-Q; Luo, H-L; Liu, Y-H; Wan, J; Zhang, J; Wei, P-F; Jiang, T; Chen, Y-H; Wang, L-P

2013-01-01

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach. PMID:24176851

Natural changes in light interact with circadian regulation at promoters to control gene expression in cyanobacteria

PubMed Central

2017-01-01

The circadian clock interacts with other regulatory pathways to tune physiology to predictable daily changes and unexpected environmental fluctuations. However, the complexity of circadian clocks in higher organisms has prevented a clear understanding of how natural environmental conditions affect circadian clocks and their physiological outputs. Here, we dissect the interaction between circadian regulation and responses to fluctuating light in the cyanobacterium Synechococcus elongatus. We demonstrate that natural changes in light intensity substantially affect the expression of hundreds of circadian-clock-controlled genes, many of which are involved in key steps of metabolism. These changes in expression arise from circadian and light-responsive control of RNA polymerase recruitment to promoters by a network of transcription factors including RpaA and RpaB. Using phenomenological modeling constrained by our data, we reveal simple principles that underlie the small number of stereotyped responses of dusk circadian genes to changes in light. PMID:29239721

Light-controlled inhibition of malignant glioma by opsin gene transfer.

PubMed

Yang, F; Tu, J; Pan, J-Q; Luo, H-L; Liu, Y-H; Wan, J; Zhang, J; Wei, P-F; Jiang, T; Chen, Y-H; Wang, L-P

2013-10-31

Glioblastomas are aggressive cancers with low survival rates and poor prognosis because of their highly proliferative and invasive capacity. In the current study, we describe a new optogenetic strategy that selectively inhibits glioma cells through light-controlled membrane depolarization and cell death. Transfer of the engineered opsin ChETA (engineered Channelrhodopsin-2 variant) gene into primary human glioma cells or cell lines, but not normal astrocytes, unexpectedly decreased cell proliferation and increased mitochondria-dependent apoptosis, upon light stimulation. These optogenetic effects were mediated by membrane depolarization-induced reductions in cyclin expression and mitochondrial transmembrane potential. Importantly, the ChETA gene transfer and light illumination in mice significantly inhibited subcutaneous and intracranial glioma growth and increased the survival of the animals bearing the glioma. These results uncover an unexpected effect of opsin ion channels on glioma cells and offer the opportunity for the first time to treat glioma using a light-controllable optogenetic approach.

A Novel Design of an Automatic Lighting Control System for a Wireless Sensor Network with Increased Sensor Lifetime and Reduced Sensor Numbers

PubMed Central

Mohamaddoust, Reza; Haghighat, Abolfazl Toroghi; Sharif, Mohamad Javad Motahari; Capanni, Niccolo

2011-01-01

Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a Lighting Automatic Control System (LACS). The LACS system contains a centralized or distributed architecture determined by application requirements and space usage. The system optimizes the calculations and communications for lighting intensity, incorporates user illumination requirements according to their activities and performs adjustments based on external lighting effects in external sensor and external sensor-less architectures. Methods are proposed for reducing the number of sensors required and increasing the lifetime of those used, for considerably reduced energy consumption. Additionally we suggest methods for improving uniformity of illuminance distribution on a workplane’s surface, which improves user satisfaction. Finally simulation results are presented to verify the effectiveness of our design. PMID:22164114

Light-Inducible Gene Regulation with Engineered Zinc Finger Proteins

PubMed Central

Polstein, Lauren R.; Gersbach, Charles A.

2014-01-01

The coupling of light-inducible protein-protein interactions with gene regulation systems has enabled the control of gene expression with light. In particular, heterodimer protein pairs from plants can be used to engineer a gene regulation system in mammalian cells that is reversible, repeatable, tunable, controllable in a spatiotemporal manner, and targetable to any DNA sequence. This system, Light-Inducible Transcription using Engineered Zinc finger proteins (LITEZ), is based on the blue light-induced interaction of GIGANTEA and the LOV domain of FKF1 that drives the localization of a transcriptional activator to the DNA-binding site of a highly customizable engineered zinc finger protein. This chapter provides methods for modifying LITEZ to target new DNA sequences, engineering a programmable LED array to illuminate cell cultures, and using the modified LITEZ system to achieve spatiotemporal control of transgene expression in mammalian cells. PMID:24718797

A novel design of an automatic lighting control system for a wireless sensor network with increased sensor lifetime and reduced sensor numbers.

PubMed

Mohamaddoust, Reza; Haghighat, Abolfazl Toroghi; Sharif, Mohamad Javad Motahari; Capanni, Niccolo

2011-01-01

Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a lighting automatic control system (LACS). The LACS system contains a centralized or distributed architecture determined by application requirements and space usage. The system optimizes the calculations and communications for lighting intensity, incorporates user illumination requirements according to their activities and performs adjustments based on external lighting effects in external sensor and external sensor-less architectures. Methods are proposed for reducing the number of sensors required and increasing the lifetime of those used, for considerably reduced energy consumption. Additionally we suggest methods for improving uniformity of illuminance distribution on a workplane's surface, which improves user satisfaction. Finally simulation results are presented to verify the effectiveness of our design.

Genotoxicity and carcinogenicity of the light emitted by artificial illumination systems.

PubMed

De Flora, Silvio

2013-03-01

The light delivered by artificial illumination systems, and in particular by halogen quartz bulbs, contains UVA, UVB, and UVC radiation, is genotoxic to both bacterial and human cells and is potently carcinogenic to hairless mice. Since IARC has classified UV radiation in Group 1, any source of UV light poses a carcinogenic hazard to humans. Suitable regulations would be needed in order to control the safety of the light emitted by artificial light sources.

Interactions of chromatic and lens-induced defocus during visual control of eye growth in guinea pigs (Cavia porcellus).

PubMed

Jiang, Liqin; Zhang, Sen; Schaeffel, Frank; Xiong, Shibo; Zheng, Yibo; Zhou, Xiangtian; Lu, Fan; Qu, Jia

2014-01-01

It was recently demonstrated that chromaticity could affect eye growth and refractive development in guinea pigs but it remained unclear whether correction with spectacle lenses could balance these effects and how retinal responses change with different spectral compositions of light. Three illumination conditions were tested: blue, red and white light. Animals were raised without or with monocular spectacle lenses from three to seven weeks of age. Luminance electroretinograms (ERGs) were recorded to explore retinal responses with the different spectral compositions. In our special colony of pigmented guinea pigs, characterized by residual hyperopia, spontaneous myopia and poor emmetropization, red light induced early thinning of the choroid and relative myopia, compared to white light. Effects of red light could not be suppressed if positive spectacle lenses were worn. ERGs showed that red light failed to elicit robust retinal responses. Blue light inhibited axial eye growth, even when animals were reared with negative lenses. Intensity-matched blue and white light elicited similar a-waves but different b-waves, suggesting that the wavelength of light affects visual control of eye growth through different processing in the inner retina. We hypothesize that blue light might stimulate preferentially the ON pathway to inhibit myopia induced by negative lenses, at least in guinea pigs. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Arabidopsis ANGUSTIFOLIA3 (AN3) is associated with the promoter of CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) to regulate light-mediated stomatal development.

PubMed

Meng, Lai-Sheng; Li, Cong; Xu, Meng-Ke; Sun, Xu-Dong; Wan, Wen; Cao, Xiao-Ying; Zhang, Jin-Lin; Chen, Kun-Ming

2018-04-12

Light signals are perceived by multiple photoreceptors that converge to suppress the RING E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) for the regulation of stomatal development. Thus, COP1 is a point of integration between light signaling and stomatal patterning. However, how light signaling is collected into COP1 for the production and spacing of stomata is still unknown. Here, we report that the loss-of-function mutant of ANGUSTIFOLIA3 (AN3) delays asymmetric cell division, which leads to decreased stomatal index. Furthermore, overexpression of AN3 accelerates asymmetric cell division, which results in clusters of stomata. In addition, the stomatal development through AN3 regulation is mediated by light signaling. Finally, we find that an3 is a light-signaling mutant, and that AN3 protein is light regulated. Self-activation by AN3 contributes to the control of AN3 expression. Thus, AN3 is a point of collection between light signaling and stomatal patterning. Target-gene analysis indicates that AN3 is associated with COP1 promoter for the regulation of light-controlling stomatal development. Together, these components for regulating stomatal development form an AN3-COP1-E3 ubiquitin ligase complex, allowing the integration of light signaling into the production and spacing of stomata. © 2018 John Wiley & Sons Ltd.

Retail lighting and packaging influence consumer acceptance of fluid milk.

PubMed

Potts, H L; Amin, K N; Duncan, S E

2017-01-01

Little is known about the effect of retail light-emitting diode (LED) exposure on consumer acceptance of milk. The study objective was to determine effects of fluorescent and LED lighting under retail storage conditions on consumer acceptance of milk. Consumer acceptance of milk stored under retail conditions was determined through sensory evaluation (2 studies; n=150+ each) and analytical measures (dissolved oxygen, secondary oxidation products, riboflavin retention). Study 1 evaluated milk stored in high-density polyethylene (HDPE) packages for 4h under LED light (960 lx). Commercially available HDPE package treatments included translucent HDPE (most commonly used), white HDPE [low concentration (1.3%) TiO 2 ], and yellow HDPE; in addition, HDPE with a higher TiO 2 concentration (high white; 4.9% TiO 2 ) and a foil-wrapped translucent HDPE (control) were tested. Translucent and control packages also were tested under fluorescent light. Study 2 evaluated polyethylene terephthalate (PET) packages for 4h under fluorescent and LED light (1,460 lx). The PET packaging included 2 treatments (medium, 4.0% TiO 2 ; high, 6.6% TiO 2 ) as well as translucent HDPE (exposed to fluorescent), clear PET (fluorescent and LED), and light-protected control. Overall mean acceptability of milk ranged from "like slightly" to "like moderately" with significantly lower acceptability for milk exposed to fluorescent light. Milk in HDPE and PET packages had comparable overall acceptability scores when exposed to LED light. Only the fluorescent light condition (both PET and HDPE) diminished overall acceptability. Fluorescent light exposure negatively influenced flavor with significant penalty (2.0-2.5 integers) to overall acceptability of milk in translucent HDPE and clear PET. The LED also diminished aftertaste of milk packaged in translucent HDPE. Changes in dissolved oxygen content, as an indication of oxidation, supported the observed differences in consumer acceptance of milk stored under fluorescent and LED light. Consumers like the flavor of fresh milk, which can be protected by selecting appropriate packaging that blocks detrimental light wavelengths. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Lighting Efficiency Changes On Horizon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richman, Eric E.; Rosenberg, Michael I.

2017-04-03

This article answers four questions posed by Facility Executive Magazine regarding the new 2016 edition of ASHRAE Standard 90.1. The discussion centers on new lighting power limits, lighting controls, and the new simulation based performance path in the standard.

Fabrication of Multi-point Side-Firing Optical Fiber by Laser Micro-ablation

PubMed Central

Nguyen, Hoang; Arnob, Md Masud Parvez; Becker, Aaron T; Wolfe, John C; Hogan, Matthew K; Horner, Philip J; Shih, Wei-Chuan

2018-01-01

A multi-point, side-firing design enables an optical fiber to output light at multiple desired locations along the fiber body. This provides advantages over traditional end-to-end fibers, especially in applications requiring fiber bundles such as brain stimulation or remote sensing. This paper demonstrates that continuous wave (CW) laser micro-ablation can controllably create conical-shaped cavities, or side windows, for outputting light. The dimensions of these cavities determine the amount of firing light and their firing angle. Experimental data show that a single side window on a 730 μm fiber can deliver more than 8 % of the input light. This was increased to more than 19 % on a 65 μm fiber with side windows created using femtosecond (fs) laser ablation and chemical etching. Fine control of light distribution along an optical fiber is critical for various biomedical applications such as light activated drug-release and optogenetics studies. PMID:28454166

Light treatment for NASA shiftworkers.

PubMed

Stewart, K T; Hayes, B C; Eastman, C I

1995-04-01

Intense artificial light can phase-shift circadian rhythms and improve performance, sleep, and well-being during shiftwork simulations. In real shiftworkers, however, exposure to sunlight and other time cues may decrease the efficacy of light treatment, and occupational and family responsibilities may make it impractical. With these considerations in mind, we designed and tested light-treatment protocols for NASA personnel who worked on shifted schedules during two Space Shuttle missions. During the prelaunch week, treatment subjects self-administered light of approximately 10,000 lux at times of day that phase-delay circadian rhythms. Treatment continued during the missions and for several days afterward. No treatment was administered to subjects in the control group. Treatment subjects reported better sleep, performance, and physical and emotional well-being than control subjects and rated the treatment as highly effective for promoting adjustment to their work schedules. Light treatment is both feasible and beneficial for NASA personnel who must work on shifted schedules during Space Shuttle missions.

Novel concept of the smart NIR-light-controlled drug release of black phosphorus nanostructure for cancer therapy.

PubMed

Qiu, Meng; Wang, Dou; Liang, Weiyuan; Liu, Liping; Zhang, Yin; Chen, Xing; Sang, David Kipkemoi; Xing, Chenyang; Li, Zhongjun; Dong, Biqin; Xing, Feng; Fan, Dianyuan; Bao, Shiyun; Zhang, Han; Cao, Yihai

2018-01-16

A biodegradable drug delivery system (DDS) is one the most promising therapeutic strategies for cancer therapy. Here, we propose a unique concept of light activation of black phosphorus (BP) at hydrogel nanostructures for cancer therapy. A photosensitizer converts light into heat that softens and melts drug-loaded hydrogel-based nanostructures. Drug release rates can be accurately controlled by light intensity, exposure duration, BP concentration, and hydrogel composition. Owing to sufficiently deep penetration of near-infrared (NIR) light through tissues, our BP-based system shows high therapeutic efficacy for treatment of s.c. cancers. Importantly, our drug delivery system is completely harmless and degradable in vivo. Together, our work proposes a unique concept for precision cancer therapy by external light excitation to release cancer drugs. If these findings are successfully translated into the clinic, millions of patients with cancer will benefit from our work.

Optical set-reset latch

DOEpatents

Skogen, Erik J.

2013-01-29

An optical set-reset (SR) latch is formed from a first electroabsorption modulator (EAM), a second EAM and a waveguide photodetector (PD) which are arranged in an optical and electrical feedback loop which controls the transmission of light through the first EAM to latch the first EAM in a light-transmissive state in response to a Set light input. A second waveguide PD controls the transmission of light through the second EAM and is used to switch the first EAM to a light-absorptive state in response to a Reset light input provided to the second waveguide PD. The optical SR latch, which may be formed on a III-V compound semiconductor substrate (e.g. an InP or a GaAs substrate) as a photonic integrated circuit (PIC), stores a bit of optical information and has an optical output for the logic state of that bit of information.

Tunneling-injection in vertical quasi-2D heterojunctions enabled efficient and adjustable optoelectronic conversion

PubMed Central

Tan, Wei-Chun; Chiang, Chia-Wei; Hofmann, Mario; Chen, Yang-Fang

2016-01-01

The advent of 2D materials integration has enabled novel heterojunctions where carrier transport proceeds thrsough different ultrathin layers. We here demonstrate the potential of such heterojunctions on a graphene/dielectric/semiconductor vertical stack that combines several enabling features for optoelectronic devices. Efficient and stable light emission was achieved through carrier tunneling from the graphene injector into prominent states of a luminescent material. Graphene’s unique properties enable fine control of the band alignment in the heterojunction. This advantage was used to produce vertical tunneling-injection light-emitting transistors (VtiLET) where gating allows adjustment of the light emission intensity independent of applied bias. This device was shown to simultaneously act as a light detecting transistor with a linear and gate tunable sensitivity. The presented development of an electronically controllable multifunctional light emitter, light detector and transistor open up a new route for future optoelectronics. PMID:27507171

Tunneling-injection in vertical quasi-2D heterojunctions enabled efficient and adjustable optoelectronic conversion

NASA Astrophysics Data System (ADS)

Tan, Wei-Chun; Chiang, Chia-Wei; Hofmann, Mario; Chen, Yang-Fang

2016-08-01

The advent of 2D materials integration has enabled novel heterojunctions where carrier transport proceeds thrsough different ultrathin layers. We here demonstrate the potential of such heterojunctions on a graphene/dielectric/semiconductor vertical stack that combines several enabling features for optoelectronic devices. Efficient and stable light emission was achieved through carrier tunneling from the graphene injector into prominent states of a luminescent material. Graphene’s unique properties enable fine control of the band alignment in the heterojunction. This advantage was used to produce vertical tunneling-injection light-emitting transistors (VtiLET) where gating allows adjustment of the light emission intensity independent of applied bias. This device was shown to simultaneously act as a light detecting transistor with a linear and gate tunable sensitivity. The presented development of an electronically controllable multifunctional light emitter, light detector and transistor open up a new route for future optoelectronics.

Fabrication of multipoint side-firing optical fiber by laser micro-ablation.

PubMed

Nguyen, Hoang; Parvez Arnob, Md Masud; Becker, Aaron T; Wolfe, John C; Hogan, Matthew K; Horner, Philip J; Shih, Wei-Chuan

2017-05-01

A multipoint, side-firing design enables an optical fiber to output light at multiple desired locations along the fiber body. This provides advantages over traditional end-to-end fibers, especially in applications requiring fiber bundles such as brain stimulation or remote sensing. This Letter demonstrates that continuous wave (CW) laser micro-ablation can controllably create conical-shaped cavities, or side windows, for outputting light. The dimensions of these cavities determine the amount of firing light and their firing angle. Experimental data show that a single side window on a 730 μm fiber can deliver more than 8% of the input light. This can be increased to more than 19% on a 65 μm fiber with side windows created using femtosecond laser ablation and chemical etching. Fine control of light distribution along an optical fiber is critical for various biomedical applications such as light-activated drug-release and optogenetics studies.

Does Long-Term Elevation of CO2 Concentration Increase Photosynthesis in Forest Floor Vegetation? (Indiana Strawberry in a Maryland Forest).

PubMed

Osborne, C. P.; Drake, B. G.; LaRoche, J.; Long, S. P.

1997-05-01

As the partial pressure of CO2 (pCO2) in the atmosphere rises, photorespiratory loss of carbon in C3 photosynthesis will diminish and the net efficiency of light-limited photosynthetic carbon uptake should rise. We tested this expectation for Indiana strawberry (Duchesnea indica) growing on a Maryland forest floor. Open-top chambers were used to elevate the pCO2 of a forest floor habitat to 67 Pa and were paired with control chambers providing an ambient pCO2 of 38 Pa. After 3.5 years, D. indica leaves grown and measured in the elevated pCO2 showed a significantly greater maximum quantum efficiency of net photosynthesis (by 22%) and a lower light compensation point (by 42%) than leaves grown and measured in the control chambers. The quantum efficiency to minimize photorespiration, measured in 1% O2, was the same for controls and plants grown at elevated pCO2. This showed that the maximum efficiency of light-energy transduction into assimilated carbon was not altered by acclimation and that the increase in light-limited photosynthesis at elevated pCO2 was simply a function of the decrease in photorespiration. Acclimation did decrease the ribulose-1,5-bisphosphate carboxylase/oxygenase and light-harvesting chlorophyll protein content of the leaf by more than 30%. These changes were associated with a decreased capacity for light-saturated, but not light-limited, photosynthesis. Even so, leaves of D. indica grown and measured at elevated pCO2 showed greater light-saturated photosynthetic rates than leaves grown and measured at the current atmospheric pCO2. In situ measurements under natural forest floor lighting showed large increases in leaf photosynthesis at elevated pCO2, relative to controls, in both summer and fall. The increase in efficiency of light-limited photosynthesis with elevated pCO2 allowed positive net photosynthetic carbon uptake on days and at locations on the forest floor that light fluxes were insufficient for positive net photosynthesis in the current atmospheric pCO2.

Does long-term elevation of CO{sub 2} concentration increase photosynthesis in forest floor vegetation? Indiana strawberry in a Maryland forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborne, C.P.; Long, S.P.; Drake, B.G.

1997-05-01

As the partial pressure of CO{sub 2} (pCO{sub 2}) in the atmosphere rises, photorespiratory loss of carbon in C, photosynthesis will diminish and the net efficiency of light-limited photosynthetic carbon uptake should rise. Indiana strawberry (Duchesnea indica) growing on a Maryland forest floor was tested. Open-top chambers were used to elevate the pCO{sub 2} of a forest floor habitat to 67 Pa and were paired with control chambers with an ambient pCO{sub 2} of 38 Pa. After 3.5 years, D. indica leaves in the elevated pCO{sub 2} showed a significantly greater maximum quantum efficiency of net photosynthesis (by 22%) andmore » a lower light compensation point (by 42%) than leaves in the control chambers. The quantum efficiency to minimize photorespiration was the same for controls and plants grown at elevated pCO{sub 2}, showing the maximum efficiency of light-energy transduction into assimilated carbon was not altered by acclimation and the increase in light-limited photosynthesis at elevated pCO{sub 2} was a function of the decrease in photorespiration. Acclimation did decrease the ribulose-1,5-bisphosphate carboxylase/oxygenase and light-harvesting chlorophyll protein content of the leaf by more than 30%. These changes were associated with a decreased capacity for light-saturated, but not light-limited, photosynthesis. Leaves of D. indica grown and measured at elevated pCO{sub 2} showed greater light-saturated photosynthetic rates than leaves grown and measured at the current atmospheric pCO{sub 2}. In situ measurements under natural lighting showed large increases in leaf photosynthesis at elevated pCO{sub 2}, relative to controls, in both summer and fall. The increase in efficiency of light-limited photosynthesis with elevated pCO{sub 2} allowed positive net photosynthetic carbon uptake on days and at locations on the forest floor that light fluxes were insufficient for positive net photosynthesis in the current atmospheric pCO{sub 2}. 33 refs., 3 figs., 3 tabs.« less

Circadian Rhythm in the Expression of the mRNA Coding for the Apoprotein of the Light-Harvesting Complex of Photosystem II 1

PubMed Central

Tavladoraki, Paraskevi; Kloppstech, Klaus; Argyroudi-Akoyunoglou, Joan

1989-01-01

The mRNA coding for light-harvesting complex of PSII (LHC-II) apoprotein is present in etiolated bean (Phaseolus vulgaris L.) leaves; its level is low in 5-day-old leaves, increases about 3 to 4 times in 9- to 13-day-old leaves, and decreases thereafter. A red light pulse induces an increase in LHC-II mRNA level, which is reversed by far red light, in all ages of the etiolated tissue tested. The phytochrome-controlled initial increase of LHC-II mRNA level is higher in 9- and 13-day-old than in 5- and 17-day-old bean leaves. The amount of LHC-II mRNA, accumulated in the dark after a red light pulse, oscillates rhythmically with a period of about 24 hours. This rhythm is also observed in continuous white light and in the dark following exposure to continuous white light, and persists for at least 70 hours. A second red light pulse, applied 36 hours after initiation of the rhythm, induces a phase-shift, which is prevented by far red light immediately following the second red light pulse. A persistent, but gradually reduced, far red reversibility of the red light-induced increase in LHC-II mRNA level is observed. In contrast, far red reversibility of the red light-induced clock setting is only observed when far red follows immediately the red light. It is concluded that (a) the light-induced LHC-II mRNA accumulation follows an endogenous, circadian rhythm, for the appearance of which a red light pulse is sufficient, (b) the circadian oscillator is under phytochrome control, and (c) a stable Pfr form, which exists for several hours, is responsible for sustaining LHC-II gene transcription. Images Figure 1 Figure 2 Figure 8 PMID:16666825

Wireless control system for two-axis linear oscillating motion applying CBR technology

NASA Astrophysics Data System (ADS)

Kuzyakov, O. N.; Andreeva, M. A.

2018-03-01

The paper presents the aspects of elaborating a movement control system. The system is to implement determination of movement characteristics of the object controlled, which performs an oscillating linear motion in a two-axis direction. The system has an electronic-optical principle of action: light receivers are attached to a controlled object, and a laser light emitter is attached to a static construction. While the object performs movement along the construction, the light emitter signal is registered by light receivers, based on which determination of the object position and characteristic of its movement are performed. An algorithm of system implementation is elaborated. Signal processing is performed on the basis of the case-based reasoning method. The system is to be used in machine-building industry in controlling relative displacement of the dynamic object or its assembly.

Morphological responses of wheat to blue light

NASA Technical Reports Server (NTRS)

Barnes, C.; Bugbee, B.

1992-01-01

Blue light significantly increased tillering in wheat (Triticum aestivum L.) plants grown at the same photosynthetic photon flux (PPF). Plants were grown under two levels of blue light (400-500 nm) in a controlled environment with continuous irradiation. Plants received either 50 micromoles m-2 s-1 of blue light or 2 micromoles m-2 s-1 blue light from filtered metal halide lamps at a total irradiance of 200 micromoles m-2 s-1 PPF (400-700 nm). Plants tillered an average of 25% more under the higher level of blue light. Blue light also caused a small, but consistent, increase in main culm development, measured as Haun stage. Leaf length was reduced by higher levels of blue light, while plant dry-mass was not significantly affected by blue light. Applying the principle of equivalent light action, the results suggest that tillering and leaf elongation are mediated by the blue-UV light receptor(s) because phytochrome photoequilibrium for each treatment were nearly identical.

Luminescence- and nanoparticle-mediated increase of light absorption by photoreceptor cells: Converting UV light to visible light.

PubMed

Li, Lei; Sahi, Sunil K; Peng, Mingying; Lee, Eric B; Ma, Lun; Wojtowicz, Jennifer L; Malin, John H; Chen, Wei

2016-02-10

We developed new optic devices - singly-doped luminescence glasses and nanoparticle-coated lenses that convert UV light to visible light - for improvement of visual system functions. Tb(3+) or Eu(3+) singly-doped borate glasses or CdS-quantum dot (CdS-QD) coated lenses efficiently convert UV light to 542 nm or 613 nm wavelength narrow-band green or red light, or wide-spectrum white light, and thereby provide extra visible light to the eye. In zebrafish (wild-type larvae and adult control animals, retinal degeneration mutants, and light-induced photoreceptor cell degeneration models), the use of Tb(3+) or Eu(3+) doped luminescence glass or CdS-QD coated glass lenses provide additional visible light to the rod and cone photoreceptor cells, and thereby improve the visual system functions. The data provide proof-of-concept for the future development of optic devices for improvement of visual system functions in patients who suffer from photoreceptor cell degeneration or related retinal diseases.

An integration time adaptive control method for atmospheric composition detection of occultation

NASA Astrophysics Data System (ADS)

Ding, Lin; Hou, Shuai; Yu, Fei; Liu, Cheng; Li, Chao; Zhe, Lin

2018-01-01

When sun is used as the light source for atmospheric composition detection, it is necessary to image sun for accurate identification and stable tracking. In the course of 180 second of the occultation, the magnitude of sun light intensity through the atmosphere changes greatly. It is nearly 1100 times illumination change between the maximum atmospheric and the minimum atmospheric. And the process of light change is so severe that 2.9 times per second of light change can be reached. Therefore, it is difficult to control the integration time of sun image camera. In this paper, a novel adaptive integration time control method for occultation is presented. In this method, with the distribution of gray value in the image as the reference variable, and the concepts of speed integral PID control, the integration time adaptive control problem of high frequency imaging. The large dynamic range integration time automatic control in the occultation can be achieved.

Light distribution properties in spinal cord for optogenetic stimulation (Conference Presentation)

NASA Astrophysics Data System (ADS)

GÄ secka, Alicja; Bahdine, Mohamed; Lapointe, Nicolas; Rioux, Veronique; Perez-Sanchez, Jimena; Bonin, Robert P.; De Koninck, Yves; Côté, Daniel

2016-03-01

Optogenetics is currently one of the most popular technique in neuroscience. It enables cell-selective and temporally-precise control of neuronal activity. Good spatial control of the stimulated area and minimized tissue damage requires a specific knowledge about light scattering properties. Light propagation in cell cultures and brain tissue is relatively well documented and allows for a precise and reliable delivery of light to the neurons. In spinal cord, light must pass through highly organized white matter before reaching cell bodies present in grey matter, this heterogenous structure makes it difficult to predict the propagation pattern. In this work we investigate the light distribution properties through mouse and monkey spinal cord. The light propagation depends on a fibers orientation, leading to less deep penetration profile in the direction perpendicular to the fibers and lower attenuation in the direction parallel to the fibers. Additionally, the use of different illumination wavelengths results in variations of the attenuation coefficient. Next, we use Monte-Carlo simulation to study light transport. The model gives a full 3-D simulation of light distribution in spinal cord and takes into account different scattering properties related to the fibers orientation. These studies are important to estimate the minimum optical irradiance required at the fiber tip to effectively excite the optogenetic proteins in a desired region of spinal cord.

Light Spectral Quality Effects on the Growth of Potato (Solanum Tuberosum L.) Nodal Cuttings in Vitro

NASA Technical Reports Server (NTRS)

Wilson, Deborah A.; Weigel, Russell C.; Wheeler, Raymond M.; Sager, John C.

1993-01-01

The effects of light spectral quality on the growth of in vitro nodal cuttings of potato (Solanum tuberosum L.) cultivars Norland, Superior, Kennebec, and Denali were examined. The different light spectra were provided by Vita-Lite fluorescent (VF) (a white light control), blue fluorescent (BF), red fluorescent (RF), low-pressure sodium (LPS), and a combination of low-pressure sodium plus cool-white fluorescent lamps (LPS/CWF). For cultivars, stem lengths after 4 wks were longest under LPS, follow by RF, LPS/CWF, VF, and BF (in descending order). Microscopic studies revealed that cells were shortest when cultured in BF or VF environments, and were longest in RF or LPS lamp environments. The highest number axillary branches occurred on plantlets grown with LPS or LPS/CWF, whereas the lowest number occurred with BF. No leaf or stem edema (callus or gall-like growths) occurred iwth LPS or LPS/cwf lighting, and no edema occurred on cv. Norland plantlets, regardless of lighting. Results suggest that shoot morphologic development of in vitro grown potato plants can be controlled by controlling irradiant spectral quality.

Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans.

PubMed

Fracalossi, Camila; Nagata, Juliana Yuri; Pellosi, Diogo Silva; Terada, Raquel Sano Suga; Hioka, Noboru; Baesso, Mauro Luciano; Sato, Francielle; Rosalen, Pedro Luiz; Caetano, Wilker; Fujimaki, Mitsue

2016-09-01

Photodynamic inactivation of microorganisms is based on a photosensitizing substance which, in the presence of light and molecular oxygen, produces singlet oxygen, a toxic agent to microorganisms and tumor cells. This study aimed to evaluate singlet oxygen quantum yield of erythrosine solutions illuminated with a halogen light source in comparison to a LED array (control), and the photodynamic effect of erythrosine dye in association with the halogen light source on Streptococcus mutans. Singlet oxygen quantum yield of erythrosine solutions was quantified using uric acid as a chemical-probe in an aqueous solution. The in vitro effect of the photodynamic antimicrobial activity of erythrosine in association with the halogen photopolimerizing light on Streptococcus mutans (UA 159) was assessed during one minute. Bacterial cultures treated with erythrosine alone served as negative control. Singlet oxygen with 24% and 2.8% degradation of uric acid in one minute and a quantum yield of 0.59 and 0.63 was obtained for the erythrosine samples illuminated with the halogen light and the LED array, respectively. The bacterial cultures with erythrosine illuminated with the halogen light presented a decreased number of CFU mL(-1) in comparison with the negative control, with minimal inhibitory concentrations between 0.312 and 0.156mgmL(-1). The photodynamic response of erythrosine induced by the halogen light was capable of killing S. mutans. Clinical trials should be conducted to better ascertain the use of erythrosine in association with halogen light source for the treatment of dental caries. Copyright © 2016 Elsevier B.V. All rights reserved.

Cardio-autonomic control and wellbeing due to oscillating color light exposure.

PubMed

Grote, Vincent; Kelz, Christina; Goswami, Nandu; Stossier, Harald; Tafeit, Erwin; Moser, Maximilian

2013-04-10

We investigated the cardio-autonomic and psychological effects of colored light cycling with the wavelength of ultradian rhythms. In two consecutive experiments, an explorative, longitudinal test followed by a randomized crossover design, 20 healthy subjects each were exposed to oscillating red, green and blue light. Heart rate, heart rate variability (HRV) and subjective wellbeing were measured. Significant effects of the oscillating color light exposure were observed for heart rate and cardio-autonomic control rhythms, derived from HRV (p≤.001). These effects on HRV were replicated in the second experiment in comparison to a similar white light exposure protocol (p≤.05). Vigilance showed improvement over the two weeks (p≤.001) in the longitudinal study. External color light cycling at the wavelength of blood pressure oscillations appears to amplify the endogenous autonomic oscillations. This leads to an optimization of cardio-autonomic control; an effect that was reflected shortly after the onset of the light exposure sessions by the increase of heart rate variability. From the results, we conclude that it takes repeated light exposure session to foster the positive effects on the psychological aspects, as we observed an increase of subjectively perceived mood only in the longitudinal study, not for the crossover design study. The results of our study imply some possible health effects of a color light exposure that is adjusted to 10 s and 1 min oscillations of humans' ultradian rhythms. These novel results show possible applications of oscillating visual inputs to the activation of processes connected to physiological regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

Light Source

NASA Technical Reports Server (NTRS)

1993-01-01

Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

JWST NIRSpec Cryogenic Light Shield Mechanism

NASA Technical Reports Server (NTRS)

Hale, Kathleen; Sharma, Rajeev

2006-01-01

The focal plane detectors for the Near-Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST) require a light tight cover for calibration along with an open field-of-view during ground performance testing within a cryogenic dewar. In order to meet the light attenuation requirements and provide open and closed fields of view without breaking vacuum, a light shield mechanism was designed. This paper describes the details of the light shield mechanism design and test results. Included is information on the labyrinth light path design, motor capability and performance, dry film lubrication, mechanism control, and mechanism cryogenic performance results.

Caged molecular beacons: controlling nucleic acid hybridization with light.

PubMed

Wang, Chunming; Zhu, Zhi; Song, Yanling; Lin, Hui; Yang, Chaoyong James; Tan, Weihong

2011-05-28

We have constructed a novel class of light-activatable caged molecular beacons (cMBs) that are caged by locking two stems with a photo-labile biomolecular interaction or covalent bond. With the cMBs, the nucleic acid hybridization process can be easily controlled with light, which offers the possibility for a high spatiotemporal resolution study of intracellular mRNAs. © The Royal Society of Chemistry 2011

Spectral lights trigger biomass accumulation and production of antioxidant secondary metabolites in adventitious root cultures of Stevia rebaudiana (Bert.).

PubMed

Idrees, Muhammad; Sania, Bibi; Hafsa, Bibi; Kumari, Sana; Khan, Haji; Fazal, Hina; Ahmad, Ishfaq; Akbar, Fazal; Ahmad, Naveed; Ali, Sadeeq; Ahmad, Nisar

2018-05-30

Stevia rebaudiana (S. rebaudiana) is the most important therapeutic plant species and has been accepted as such worldwide. It has a tendency to accumulate steviol glycosides, which are 300 times sweeter than marketable sugar. Recently, diabetic patients commonly use this plant as a sugar substitute for sweet taste. In the present study, the effects of different spectral lights were investigated on biomass accumulation and production of secondary metabolites in adventitious root cultures of S. rebaudiana. For callus development, leaf explants were excised from seed-derived plantlets and inoculated on a Murashige and Skoog (MS) medium containing the combination of 2,4-dichlorophenoxy acetic acid (2, 4-D, 2.0mg/l) and 6-benzyladenine (BA, 2.0mg/l), while 0.5mg/l naphthalene acetic acid (NAA) was used for adventitious root culture. Adventitious root cultures were exposed to different spectral lights (blue, green, violet, red and yellow) for a 30-day period. White light was used as control. The growth kinetics was studied for 30days with 3-day intervals. In this study, the violet light showed the maximum accumulation of fresh biomass (2.495g/flask) as compared to control (1.63g/flask), while red light showed growth inhibition (1.025g/flask) as compared to control. The blue light enhanced the highest accumulation of phenolic content (TPC; 6.56mg GAE/g DW), total phenolic production (TPP; 101mg/flask) as compared to control (5.44mg GAE/g DW; 82.2mg GAE/g DW), and exhibited a strong correlation with dry biomass. Blue light also improved the accumulation of total flavonoid content (TFC; 4.33mg RE/g DW) and total flavonoid production (TFP; 65mg/flask) as compared to control. The violet light showed the highest DPPH inhibition (79.72%), while the lowest antioxidant activity was observed for control roots (73.81%). Hence, we concluded that the application of spectral lights is an auspicious strategy for the enhancement of the required antioxidant secondary metabolites in adventitious root cultures of S. rebaudiana and of other medicinal plants. Copyright © 2018 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Photocontrol of Drug Release from Supramolecular Hydrogels with Green Light.

PubMed

Karcher, Johannes; Pianowski, Zbigniew

2018-06-26

Photoresponsive smart materials transform light energy into sophisticated functions. They find increasing biomedical applications in light-induced drug release and photopharmacology, as they can locally provide the desired therapeutic effect due to precise spatiotemporal dosage control. However, the majority of reported studies rely on cytotoxic UV light that poorly penetrates tissues. Here we report the first drug-releasing system based on photochromic low molecular weight supramolecular hydrogels that is triggered with visible light. We demonstrated green-light-induced release of structurally unmodified antibiotic, anticancer, and anti-inflammatory drugs under physiological conditions. Using the antibiotic-loaded gel, we selectively inhibited bacterial growth with green light. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aluminum-nanodisc-induced collective lattice resonances: Controlling the light extraction in organic light emitting diodes

NASA Astrophysics Data System (ADS)

Auer-Berger, Manuel; Tretnak, Veronika; Wenzl, Franz-Peter; Krenn, Joachim R.; List-Kratochvil, Emil J. W.

2017-10-01

We examine aluminum-nanodisc-induced collective lattice resonances as a means to enhance the efficiency of organic light emitting diodes. Thus, nanodisc arrays were embedded in the hole transporting layer of a solution-processed phosphorescent organic blue-light emitting diode. Through extinction spectroscopy, we confirm the emergence of array-induced collective lattice resonances within the organic light emitting diode. Through finite-difference time domain simulations, we show that the collective lattice resonances yield an enhancement of the electric field intensity within the emissive layer. The effectiveness for improving the light generation and light outcoupling is demonstrated by electro-optical characterization, realizing a gain in a current efficiency of 35%.

Suppression of cucumber powdery mildew by UV-B is affected by background light quality

USDA-ARS?s Scientific Manuscript database

Brief (5-10 min) exposure to UV-B radiation (280-300 nm) suppressed powdery mildew (Podosphaera xanthii) on Cucumis sativus. The effect was enhanced by red light (600-660 nm), but offset by blue light (420-500 nm) and UV-A (300-420 nm). Compared to untreated controls, 2 h red light from specific lig...

40 CFR 86.099-17 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Model Year New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Engines, and for 1985 and Later Model Year New Gasoline Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled... regulations shall be evaluated periodically, but no less frequently than once per Urban Dynamometer Driving...

Light pollution disrupts sleep in free-living animals.

PubMed

Raap, Thomas; Pinxten, Rianne; Eens, Marcel

2015-09-04

Artificial lighting can alter individual behaviour, with often drastic and potentially negative effects on biological rhythms, daily activity and reproduction. Whether this is caused by a disruption of sleep, an important widespread behaviour enabling animals to recover from daily stress, is unclear. We tested the hypothesis that light pollution disrupts sleep by recording individual sleep behaviour of great tits, Parus major, that were roosting in dark nest-boxes and were exposed to light-emitting diode light the following night. Their behaviour was compared to that of control birds sleeping in dark nest-boxes on both nights. Artificial lighting caused experimental birds to wake up earlier, sleep less (-5%) and spent less time in the nest-box as they left their nest-box earlier in the morning. Experimental birds did not enter the nest-box or fall asleep later than controls. Although individuals in lit nest-boxes did not wake up more often nor decreased the length of their sleep bouts, females spent a greater proportion of the night awake. Our study provides the first direct proof that light pollution has a significant impact on sleep in free-living animals, in particular in the morning, and highlights a mechanism for potential effects of light pollution on fitness.

Energy Engineering Analysis Program (EEAP), Limited Energy Study-Lighting Fort Campbell, Kentucky: Volume 1-Sections 1-5

DTIC Science & Technology

1994-09-23

Buildings, and Blanchfield Hospital buildings B and C. The energy conservation opportunities (ECOs) evaluated were high efficiency interior and exterior lighting, and indoor lighting controls . Cost estimates were prepared.

40 CFR Appendix III to Subpart S... - As-Received Inspection

Code of Federal Regulations, 2010 CFR

2010-07-01

...) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... Reading 7. Build Date 8. MIL light on/off status 9. Readiness code status 10. Stored OBD codes 11.Any...

14. INTERIOR OF BEDROOM NO. 1 SHOWING ORIGINAL 6LIGHT OVER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. INTERIOR OF BEDROOM NO. 1 SHOWING ORIGINAL 6-LIGHT OVER 1-LIGHT WINDOWS ON SOUTH AND WEST WALLS. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Control Station, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

Improving NIR snow pit stratigraphy observations by introducing a controlled NIR light source

NASA Astrophysics Data System (ADS)

Dean, J.; Marshall, H.; Rutter, N.; Karlson, A.

2013-12-01

Near-infrared (NIR) photography in a prepared snow pit measures mm-/grain-scale variations in snow structure, as reflectivity is strongly dependent on microstructure and grain size at the NIR wavelengths. We explore using a controlled NIR light source to maximize signal to noise ratio and provide uniform incident, diffuse light on the snow pit wall. NIR light fired from the flash is diffused across and reflected by an umbrella onto the snow pit; the lens filter transmits NIR light onto the spectrum-modified sensor of the DSLR camera. Lenses are designed to refract visible light properly, not NIR light, so there must be a correction applied for the subsequent NIR bright spot. To avoid interpolation and debayering algorithms automatically performed by programs like Adobe's Photoshop on the images, the raw data are analyzed directly in MATLAB. NIR image data show a doubling of the amount of light collected in the same time for flash over ambient lighting. Transitions across layer boundaries in the flash-lit image are detailed by higher camera intensity values than ambient-lit images. Curves plotted using median intensity at each depth, normalized to the average profile intensity, show a separation between flash- and ambient-lit images in the upper 10-15 cm; the ambient-lit image curve asymptotically approaches the level of the flash-lit image curve below 15cm. We hypothesize that the difference is caused by additional ambient light penetrating the upper 10-15 cm of the snowpack from above and transmitting through the wall of the snow pit. This indicates that combining NIR ambient and flash photography could be a powerful technique for studying penetration depth of radiation as a function of microstructure and grain size. The NIR flash images do not increase the relative contrast at layer boundaries; however, the flash more than doubles the amount of recorded light and controls layer noise as well as layer boundary transition noise.

Modification in oxidative processes in muscle tissues exposed to laser- and light-emitting diode radiation.

PubMed

Monich, Victor A; Bavrina, Anna P; Malinovskaya, Svetlana L

2018-01-01

Exposure of living tissues to high-intensity red or near-infrared light can produce the oxidative stress effects both in the target zone and adjacent ones. The protein oxidative modification (POM) products can be used as reliable and early markers of oxidative stress. The contents of modified proteins in the investigated specimens can be evaluated by the 2,4-dinitrophenylhydrazine assay (the DNPH assay). Low-intensity red light is able to decrease the activity of oxidative processes and the DNPH assay data about the POM products in the biological tissues could show both an oxidative stress level and an efficiency of physical agent protection against the oxidative processes. Two control groups of white rats were irradiated by laser light, the first control group by red light and the second one by near-infrared radiation (NIR).Two experimental groups were consequently treated with laser and red low-level light-emitting diode radiation (LED). One of them was exposed to red laser light + LED and the other to NIR + LED. The fifth group was intact. Each group included ten animals. The effect of laser light was studied by methods of protein oxidative modifications. We measured levels of both induced and spontaneous POM products by the DNPH assay. The dramatic increase in levels of POM products in the control group samples when compared with the intact group data as well as the sharp decrease in the POM products in the experimental groups treated with LED low-level light were statistically significant (p ≤ 0.05). Exposure of skeletal muscles to high-intensity red and near-infrared laser light causes oxidative stress that continues not less than 3 days. The method of measurement of POM product contents by the DNPH assay is a reliable test of an oxidative process rate. Red low-intensity LED radiation can provide rehabilitation of skeletal muscle tissues treated with high-intensity laser light.

Anchoring energy of photo-sensitive polyimide alignment film containing methoxy cinnamate

NASA Astrophysics Data System (ADS)

Kim, Suyoung; Shin, Sung Eui; Shin, DongMyung

2010-02-01

Photosensitive polyimide containing 2-methoxy cinnamate was synthesized for photo-alignment layer of liquid crystals (LCs). 2-Methoxy cinnamic acid was confirmed photo-sensitive material by linearly polarized UV light. We studied that effect of polarized UV light on rubbed polyimide film. Anchoring energy of liquid crystal with aligning surface was measured. Irradiation of depolarized UV light on rubbed Polyimide film suppressed effective anchoring energy. Linearly polarized UV light on rubbed polyimide film controlled anchoring energy effectively. Polyimide film containing 2-methoxy cinnamate can control the photo-alignment layer easily due to its photo-sensitivity.

Phototropism: at the crossroads of light-signaling pathways.

PubMed

Goyal, Anupama; Szarzynska, Bogna; Fankhauser, Christian

2013-07-01

Phototropism enables plants to orient growth towards the direction of light and thereby maximizes photosynthesis in low-light environments. In angiosperms, blue-light photoreceptors called phototropins are primarily involved in sensing the direction of light. Phytochromes and cryptochromes (sensing red/far-red and blue light, respectively) also modulate asymmetric hypocotyl growth, leading to phototropism. Interactions between different light-signaling pathways regulating phototropism occur in cryptogams and angiosperms. In this review, we focus on the molecular mechanisms underlying the co-action between photosensory systems in the regulation of hypocotyl phototropism in Arabidopsis thaliana. Recent studies have shown that phytochromes and cryptochromes enhance phototropism by controlling the expression of important regulators of phototropin signaling. In addition, phytochromes may also regulate growth towards light via direct interaction with the phototropins. Copyright © 2013 Elsevier Ltd. All rights reserved.

49 CFR 218.5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... distinguishable blue flag or blue light by day and a blue light at night. When attached to the operating controls... the exclusive control of mechanical department personnel. Controlling locomotive means a locomotive arranged as having the only controls over all electrical, mechanical and pneumatic functions for one or...

49 CFR 218.5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... distinguishable blue flag or blue light by day and a blue light at night. When attached to the operating controls... the exclusive control of mechanical department personnel. Controlling locomotive means a locomotive arranged as having the only controls over all electrical, mechanical and pneumatic functions for one or...

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

PubMed Central

Xu, Yanfeng; Han, Yunlin; Jiang, Binbin; Huang, Lan; Zhu, Hua; Xu, Yuhuan; Yang, Weiling; Qin, Chuan

2016-01-01

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 endothelial cell proliferation. An increase in the exposure time to 30 min did not confer any additional benefit in both red and blue light groups. This study provides a theoretical basis for the potential therapeutic application of LED light in clinical settings. PMID:27347879

Coherent control in bulk and nanostructure semiconductors

NASA Astrophysics Data System (ADS)

Sipe, John E.; van Driel, Henry M.

1998-04-01

Laser light has been used as a probe of atoms, molecules, and solids since the invention of the laser. The use of laser light in a more active role, to modify and process surfaces, and initiate chemical reactions, followed shortly thereafter. But usually it is the intensity and the directionality of the laser light that is employed, not necessarily its coherence, and not particularly the fact that it has a well-defined phase. 'Coherence control' can be broadly understood as the set of processes whereby light modifies matter in a way that is critically dependent on the incident light beams possessing well-defined phases. While in a laser matter is manipulated to produce light of the desired properties, in coherent control light is manipulated -- in particular, its phase and intensity is adjusted -- to produce a material response of the desired type. Of the various coherent control processes that are currently being investigated, some involve a transition in the material medium from an initial state to a final state by two or more possible processes. With each of these is associated a quantum mechanical amplitude, and hence the probability for the transition can show interference effects between the two amplitudes, just as in the familiar two-slit interference experiment the probability for the electron to be observed at a given position involves a probability that is the square of the sum of two amplitudes. In quantum interference control (QUIC), the relative phase of the two amplitudes is adjusted by adjusting the relative phase of two polarizations of a single beam, or the relative phase of two beams at different frequencies. It is this particular type of coherent control that is of interest in this communication.

A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Bennett N., E-mail: bennett.walker@fda.hhs.gov; Office of Device Evaluation, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993; James, Robert H.

Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearlymore » 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.« less

System and Method for Scan Range Gating

NASA Technical Reports Server (NTRS)

Lindemann, Scott (Inventor); Zuk, David M. (Inventor)

2017-01-01

A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

Light emitting diodes as a plant lighting source

NASA Technical Reports Server (NTRS)

Bula, R. J.; Tennessen, D. J.; Morrow, R. C.; Tibbitts, T. W.

1994-01-01

Electroluminescence in solid materials is defined as the generation of light by the passage of an electric current through a body of solid material under an applied electric field. A specific type of electroluminescence, first noted in 1923, involves the generation of photons when electrons are passed through a p-n junction of certain solid materials (junction of a n-type semiconductor, an electron donor, and a p-type semiconductor, an electron acceptor). The development of this light emitting semiconductor technology dates back less than 30 years. During this period of time, the LED has evolved from a rare and expensive light generating device to one of the most widely used electronic components. A number of LED characteristics are of considerable importance in selecting a light source for plant lighting in a controlled environment facility. Of particular importance is the characteristic that light is generated by an LED at a rate far greater than the corresponding thermal radiation predicted by the bulk temperature of the device as defined by Plank's radiation law. This is in sharp contrast to other light sources, such as an incandescent or high intensity discharge lamp. A plant lighting system for controlled environments must provide plants with an adequate flux of photosynthetically active radiation, plus providing photons in the spectral regions that are involved in the photomorphogenic and phototropic responses that result in normal plant growth and development. Use of light sources that emit photons over a broad spectral range generally meet these two lighting requirements. Since the LED's emit over specific spectral regions, they must be carefully selected so that the levels of photsynthetically active and photomorphogenic and phototropic radiation meet these plant requirements.

Stimulation with monochromatic green light during incubation alters satellite cell mitotic activity and gene expression in relation to embryonic and posthatch muscle growth of broiler chickens.

PubMed

Zhang, L; Zhang, H J; Wang, J; Wu, S G; Qiao, X; Yue, H Y; Yao, J H; Qi, G H

2014-01-01

Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1- and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.

Polarization Control of Morphological Pattern Orientation During Light-Mediated Synthesis of Nanostructured Se–Te Films

DOE PAGES

Carim, Azhar I.; Batara, Nicolas A.; Premkumar, Anjali; ...

2015-11-23

The template-free growth of well ordered, highly anisotropic lamellar structures has been demonstrated during the photoelectrodeposition of Se–Te films, wherein the orientation of the pattern can be directed by orienting the linear polarization of the incident light. This control mechanism was investigated further herein by examining the morphologies of films grown photoelectrochemically using light from two simultaneous sources that had mutually different linear polarizations. Photoelectrochemical growth with light from two nonorthogonally polarized same-wavelength sources generated lamellar morphologies in which the long axes of the lamellae were oriented parallel to the intensity-weighted average polarization orientation. Simulations of light scattering at themore » solution–film interface were consistent with this observation. Computer modeling of these growths using combined full-wave electromagnetic and Monte Carlo growth simulations successfully reproduced the experimental morphologies and quantitatively agreed with the pattern orientations observed experimentally by considering only the fundamental light-material interactions during growth. Deposition with light from two orthogonally polarized same-wavelength as well as different-wavelength sources produced structures that consisted of two intersecting sets of orthogonally oriented lamellae in which the relative heights of the two sets could be varied by adjusting the relative source intensities. Simulations of light absorption were performed in analogous, idealized intersecting lamellar structures and revealed that the lamellae preferentially absorbed light polarized with the electric field vector along their long axes. In conclusion, these data sets cumulatively indicate that anisotropic light scattering and light absorption generated by the light polarization produces the anisotropic morphology and that the resultant morphology is a function of all illumination inputs despite differing polarizations.« less

Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

PubMed Central

Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

2015-01-01

This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work. PMID:25875189

Focused fluorescence excitation with time-reversed ultrasonically encoded light and imaging in thick scattering media

NASA Astrophysics Data System (ADS)

Lai, Puxiang; Suzuki, Yuta; Xu, Xiao; Wang, Lihong V.

2013-07-01

Scattering dominates light propagation in biological tissue, and therefore restricts both resolution and penetration depth in optical imaging within thick tissue. As photons travel into the diffusive regime, typically 1 mm beneath human skin, their trajectories transition from ballistic to diffusive due to the increased number of scattering events, which makes it impossible to focus, much less track, photon paths. Consequently, imaging methods that rely on controlled light illumination are ineffective in deep tissue. This problem has recently been addressed by a novel method capable of dynamically focusing light in thick scattering media via time reversal of ultrasonically encoded (TRUE) diffused light. Here, using photorefractive materials as phase conjugate mirrors, we show a direct visualization and dynamic control of optical focusing with this light delivery method, and demonstrate its application for focused fluorescence excitation and imaging in thick turbid media. These abilities are increasingly critical for understanding the dynamic interactions of light with biological matter and processes at different system levels, as well as their applications for biomedical diagnosis and therapy.

Fluorescent light induces neurodegeneration in the rodent nigrostriatal system but near infrared LED light does not.

PubMed

Romeo, Stefania; Vitale, Flora; Viaggi, Cristina; di Marco, Stefano; Aloisi, Gabriella; Fasciani, Irene; Pardini, Carla; Pietrantoni, Ilaria; Di Paolo, Mattia; Riccitelli, Serena; Maccarone, Rita; Mattei, Claudia; Capannolo, Marta; Rossi, Mario; Capozzo, Annamaria; Corsini, Giovanni U; Scarnati, Eugenio; Lozzi, Luca; Vaglini, Francesca; Maggio, Roberto

2017-05-01

We investigated the effects of continuous artificial light exposure on the mouse substantia nigra (SN). A three month exposure of C57Bl/6J mice to white fluorescent light induced a 30% reduction in dopamine (DA) neurons in SN compared to controls, accompanied by a decrease of DA and its metabolites in the striatum. After six months of exposure, neurodegeneration progressed slightly, but the level of DA returned to the basal level, while the metabolites increased with respect to the control. Three month exposure to near infrared LED light (∼710nm) did not alter DA neurons in SN, nor did it decrease DA and its metabolites in the striatum. Furthermore mesencephalic cell viability, as tested by [ 3 H]DA uptake, did not change. Finally, we observed that 710nm LED light, locally conveyed in the rat SN, could modulate the firing activity of extracellular-recorded DA neurons. These data suggest that light can be detrimental or beneficial to DA neurons in SN, depending on the source and wavelength. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses

PubMed Central

Brown, Barbara B.; Tribby, Calvin P.; Tharp, Doug; Flick, Kristi; Miller, Harvey J.; Smith, Ken R.; Jensen, Wyatt

2015-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the “displacement” measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant (p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services. PMID:26543329

Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses.

PubMed

Werner, Carol M; Brown, Barbara B; Tribby, Calvin P; Tharp, Doug; Flick, Kristi; Miller, Harvey J; Smith, Ken R; Jensen, Wyatt

2016-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the "displacement" measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant ( p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services.

Coral photobiology: new light on old views.

PubMed

Iluz, David; Dubinsky, Zvy

2015-04-01

The relationship between reef-building corals and light-harvesting pigments of zooxanthellae (Symbiodinium sp.) has been acknowledged for decades. The photosynthetic activity of the algal endocellular symbionts may provide up to 90% of the energy needed for the coral holobiont. This relationship limits the bathymetric distribution of coral reefs to the upper 100 m of tropical shorelines. However, even corals growing under high light intensities have to supplement the photosynthates translocated from the algae by predation on nutrient-rich zooplankton. New information has revealed how the fate of carbon acquired through photosynthesis differs from that secured by predation, whose rates are controlled by light-induced tentacular extension. The Goreau paradigm of "light-enhanced calcification" is being reevaluated, based on evidence that blue light stimulates coral calcification independently from photosynthesis rates. Furthermore, under dim light, calcification rates were stoichiometrically uncoupled from photosynthesis. The rates of photosynthesis of the zooxanthellae exhibit a clear endogenous rhythmicity maintained by light patterns. This daily pattern is concomitant with a periodicity of all the antioxidant protective mechanisms that wax and wane to meet the concomitant fluctuation in oxygen evolution. The phases of the moon are involved in the triggering of coral reproduction and control the spectacular annual mass-spawning events taking place in several reefs. The intensity and directionality of the underwater light field affect the architecture of coral colonies, leading to an optimization of the exposure of the zooxanthellae to light. We present a summary of major gaps in our understanding of the relationship between light and corals as a roadmap for future research. Copyright © 2014 Elsevier GmbH. All rights reserved.

Upper-Room Ultraviolet Light and Negative Air Ionization to Prevent Tuberculosis Transmission

PubMed Central

Escombe, A. Roderick; Moore, David A. J; Gilman, Robert H; Navincopa, Marcos; Ticona, Eduardo; Mitchell, Bailey; Noakes, Catherine; Martínez, Carlos; Sheen, Patricia; Ramirez, Rocio; Quino, Willi; Gonzalez, Armando; Friedland, Jon S; Evans, Carlton A

2009-01-01

Background Institutional tuberculosis (TB) transmission is an important public health problem highlighted by the HIV/AIDS pandemic and the emergence of multidrug- and extensively drug-resistant TB. Effective TB infection control measures are urgently needed. We evaluated the efficacy of upper-room ultraviolet (UV) lights and negative air ionization for preventing airborne TB transmission using a guinea pig air-sampling model to measure the TB infectiousness of ward air. Methods and Findings For 535 consecutive days, exhaust air from an HIV-TB ward in Lima, Perú, was passed through three guinea pig air-sampling enclosures each housing approximately 150 guinea pigs, using a 2-d cycle. On UV-off days, ward air passed in parallel through a control animal enclosure and a similar enclosure containing negative ionizers. On UV-on days, UV lights and mixing fans were turned on in the ward, and a third animal enclosure alone received ward air. TB infection in guinea pigs was defined by monthly tuberculin skin tests. All guinea pigs underwent autopsy to test for TB disease, defined by characteristic autopsy changes or by the culture of Mycobacterium tuberculosis from organs. 35% (106/304) of guinea pigs in the control group developed TB infection, and this was reduced to 14% (43/303) by ionizers, and to 9.5% (29/307) by UV lights (both p < 0.0001 compared with the control group). TB disease was confirmed in 8.6% (26/304) of control group animals, and this was reduced to 4.3% (13/303) by ionizers, and to 3.6% (11/307) by UV lights (both p < 0.03 compared with the control group). Time-to-event analysis demonstrated that TB infection was prevented by ionizers (log-rank 27; p < 0.0001) and by UV lights (log-rank 46; p < 0.0001). Time-to-event analysis also demonstrated that TB disease was prevented by ionizers (log-rank 3.7; p = 0.055) and by UV lights (log-rank 5.4; p = 0.02). An alternative analysis using an airborne infection model demonstrated that ionizers prevented 60% of TB infection and 51% of TB disease, and that UV lights prevented 70% of TB infection and 54% of TB disease. In all analysis strategies, UV lights tended to be more protective than ionizers. Conclusions Upper-room UV lights and negative air ionization each prevented most airborne TB transmission detectable by guinea pig air sampling. Provided there is adequate mixing of room air, upper-room UV light is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings. PMID:19296717

Wireless sensor and actuator networks for lighting energy efficiency and user satisfaction

NASA Astrophysics Data System (ADS)

Wen, Yao-Jung

Buildings consume more than one third of the primary energy generated in the U.S., and lighting alone accounts for approximately 30% of the energy usage in commercial buildings. As the largest electricity consumer of all building electrical systems, lighting harbors the greatest potential for energy savings in the commercial sector. Fifty percent of current energy consumption could be reduced with energy-efficient lighting management strategies. While commercial products do exist, they are poorly received due to exorbitant retrofitting cost and unsatisfactory performance. As a result, most commercial buildings, especially legacy buildings, have not taken advantage of the opportunity to generate savings from lighting. The emergence of wireless sensor and actuator network (WSAN) technologies presents an alternative that circumvents costly rewiring and promises better performance than existing commercial lighting systems. The goal of this dissertation research is to develop a framework for wireless-networked lighting systems with increased cost effectiveness, energy efficiency, and user satisfaction. This research is realized through both theoretical developments and implementations. The theoretical research aims at developing techniques for harnessing WSAN technologies to lighting hardware and control strategies. Leveraging redundancy, a sensor validation and fusion algorithm is developed for extracting pertinent lighting information from the disturbance-prone desktop-mounted photosensors. An adaptive sensing strategy optimizes the timing of data acquisition and power-hungry wireless transmission of sensory feedback in real-time lighting control. Exploiting the individual addressability of wireless-enabled luminaires, a lighting optimization algorithm is developed to create the optimal lighting that minimizes energy usage while satisfying occupants' diverse lighting preferences. The wireless-networked lighting system was implemented and tested in a number of real-life settings. A human subject study conducted in a private office concluded that the research system was competitive with the commercial lighting system with much fewer retrofitting requirements. The system implemented in a shared-space office realized a self-configuring mesh network with wireless photosensors and light actuators, and demonstrated a 50% energy savings and increased performance when harvesting daylight through windows is possible. The cost analysis revealed a reasonable payback period after the system is optimized for commercialization and confirms the marketing feasibility.

Reduction of lighting energy consumption in office buildings through improved daylight design

NASA Astrophysics Data System (ADS)

Papadouri, Maria Violeta Prado

This study aims to investigate the lighting energy consumption in office buildings and the options for its reduction. One way to reduce lighting energy consumption is by improving the daylight design. A better use of daylight in buildings might be an outcome from the effort made in different directions. Like the improvement of a building's fabric and layout, the materials, even the furniture in a space influences the daylight quality considerably. Also very important role in lighting energy consumption has the development of more efficient lighting technology like the electric lighting control systems, such as photo sensors and occupancy sensors. Both systems are responsible so that the electric light is not used without reason. As the focusing area of this study, is to find ways to improve the daylight use in buildings, a consequent question is which are the methods provided in order to achieve this The accuracy of the methodology used is also an important issue in order to achieve reliable results. The methodology applied in this study includes the analysis of a case study by taking field measurements and computer simulations. The first stage included gathering information about the lighting design of the building and monitoring the light levels, both from natural and from the electric lighting. The second stage involved testing with computer simulations, different parameters that were expected to improve the daylight exploitation of the specific area. The results of the field measurements showed that the main problems of the space were the low natural light levels and the poor daylight distribution. The annual electric lighting energy consumption, as it was calculated with the use of computer simulations, represented the annual energy consumption of a typical air-conditioned prestige office building (energy consumption guide 19, for energy use in offices, 2000). After several computer simulations, the results showed that initial design parameters of the building can affect the lighting energy consumption of the space significantly. On the other hand, relatively small changes, like changing the reflectance of the surfaces and the lighting control systems can make even more difference to the light quality of the space and the reduction of lighting energy consumption.

Natural light illumination system.

PubMed

Whang, Allen Jong-Woei; Chen, Yi-Yung; Yang, Shu-Hua; Pan, Po-Hsuan; Chou, Kao-Hsu; Lee, Yu-Chi; Lee, Zong-Yi; Chen, Chi-An; Chen, Cheng-Nan

2010-12-10

In recent years, green energy has undergone a lot of development and has been the subject of many applications. Many research studies have focused on illumination with sunlight as a means of saving energy and creating healthy lighting. Natural light illumination systems have collecting, transmitting, and lighting elements. Today, most daylight collectors use dynamic concentrators; these include Sun tracking systems. However, this design is too expensive to be cost effective. To create a low-cost collector that can be easily installed on a large building, we have designed a static concentrator, which is prismatic and cascadable, to collect sunlight for indoor illumination. The transmission component uses a large number of optical fibers. Because optical fibers are expensive, this means that most of the cost for the system will be related to transmission. In this paper, we also use a prismatic structure to design an optical coupler for coupling n to 1. With the n-to-1 coupler, the number of optical fibers necessary can be greatly reduced. Although this new natural light illumination system can effectively guide collected sunlight and send it to the basement or to other indoor places for healthy lighting, previously there has been no way to manage the collected sunlight when lighting was not desired. To solve this problem, we have designed an optical switch and a beam splitter to control and separate the transmitted light. When replacing traditional sources, the lighting should have similar characteristics, such as intensity distribution and geometric parameters, to those of traditional artificial sources. We have designed, simulated, and optimized an illumination lightpipe with a dot pattern to redistribute the collected sunlight from the natural light illumination system such that it equals the qualities of a traditional lighting system. We also provide an active lighting module that provides lighting from the natural light illumination system or LED auxiliary sources, depending on circumstances. The system is controlled by a light detector. We used optical simulation tools to design and simulate the efficiency of the active module. Finally, we used the natural light illumination system to provide natural illumination for a traffic tunnel. This system will provide a great number of benefits for the people who use it.

Ferroelectric Light Control Device

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Kim, Jae-Woo (Inventor); Elliott, Jr., James R. (Inventor)

2008-01-01

A light control device is formed by ferroelectric material and N electrodes positioned adjacent thereto to define an N-sided regular polygonal region or circular region there between where N is a multiple of four.

Ultra-high enhancement of light focusing through disordered media controlled by mega-pixel modes (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yu, Hyeonseung; Lee, KyeoReh; Park, YongKeun

2017-02-01

Developing an efficient strategy for light focusing through scattering media is an important topic in the study of multiple light scattering. The enhancement factor of the light focusing, defined as the ratio between the optimized intensity and the background intensity is proportional to the number of controlling modes in a spatial light modulator (SLM). The demonstrated enhancement factors in previous studies are typically less than 1,000 due to several limiting factors, such as the slow refresh rate of a LCoS SLM, long optimization time, and lack of an efficient algorithm for high controlling modes. A digital micro-mirror device is an amplitude modulator, which is recently widely used for fast optimization through dynamic biological tissues. The fast frame rate of the DMD up to 16 kHz can also be exploited for increasing the number of controlling modes. However, the manipulation of large pattern data and efficient calculation of the optimized pattern remained as an issue. In this work, we demonstrate the enhancement factor more than 100,000 in focusing through scattering media by using 1 Mega controlling modes of a DMD. Through careful synchronization between a DMD, a photo-detector and an additional computer for parallel optimization, we achieved the unprecedented enhancement factor with 75 mins of the optimization time. We discuss the design principles of the system and the possible applications of the enhanced light focusing.

Genome-wide regulation of light-controlled seedling morphogenesis by three families of transcription factors.

PubMed

Shi, Hui; Lyu, Mohan; Luo, Yiwen; Liu, Shoucheng; Li, Yue; He, Hang; Wei, Ning; Deng, Xing Wang; Zhong, Shangwei

2018-06-19

Three families of transcription factors have been reported to play key roles in light control of Arabidopsis seedling morphogenesis. Among them, bHLH protein PIFs and plant-specific protein EIN3/EIN3-LIKE 1 (EIN3/EIL1) accumulate in the dark to maintain skotomorphogenesis. On the other hand, HY5 and HY5 HOMOLOG (HYH), two related bZIP proteins, are stabilized in light and promote photomorphogenic development. To systemically investigate the transcriptional regulation of light-controlled seedling morphogenesis, we generated HY5 ox/ pifQein3eil1 , which contained mutations of EIN3/EIL1 and four PIF genes ( pifQein3eil1 ) and overexpression of HY5 Our results show that dark-grown HY5 ox/ pifQein3eil1 seedlings display a photomorphogenesis highly similar to that of wild-type seedlings grown in continuous light, with remarkably enhanced photomorphogenic phenotypes compared with the pifQ mutants. Consistent with the genetic evidence, transcriptome analysis indicated that PIFs, EIN3/EIL1, and HY5 are dominant transcription factors in collectively mediating a wide range of light-caused genome-wide transcriptional changes. Moreover, PIFs and EIN3/EIL1 independently control the expression of light-regulated genes such as HLS1 to cooperatively regulate apical hook formation, hypocotyl elongation, and cotyledon opening and expansion. This study illustrates a comprehensive regulatory network of transcription activities that correspond to specific morphological aspects in seedling skotomorphogenesis and photomorphogenesis.

LED-based endoscopic light source for spectral imaging

NASA Astrophysics Data System (ADS)

Browning, Craig M.; Mayes, Samuel; Favreau, Peter; Rich, Thomas C.; Leavesley, Silas J.

2016-03-01

Colorectal cancer is the United States 3rd leading cancer in death rates.1 The current screening for colorectal cancer is an endoscopic procedure using white light endoscopy (WLE). There are multiple new methods testing to replace WLE, for example narrow band imaging and autofluorescence imaging.2 However, these methods do not meet the need for a higher specificity or sensitivity. The goal for this project is to modify the presently used endoscope light source to house 16 narrow wavelength LEDs for spectral imaging in real time while increasing sensitivity and specificity. The process to do such was to take an Olympus CLK-4 light source, replace the light and electronics with 16 LEDs and new circuitry. This allows control of the power and intensity of the LEDs. This required a larger enclosure to house a bracket system for the solid light guide (lightpipe), three new circuit boards, a power source and National Instruments hardware/software for computer control. The results were a successfully designed retrofit with all the new features. The LED testing resulted in the ability to control each wavelength's intensity. The measured intensity over the voltage range will provide the information needed to couple the camera for imaging. Overall the project was successful; the modifications to the light source added the controllable LEDs. This brings the research one step closer to the main goal of spectral imaging for early detection of colorectal cancer. Future goals will be to connect the camera and test the imaging process.

The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights

PubMed Central

Rowse, Elizabeth G.; Harris, Stephen; Jones, Gareth

2016-01-01

We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS) to light emitting diode (LED) street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum ‘white’ light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes), or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these ‘light-intolerant’ bat species. PMID:27008274

Photoreactivity of the occipital cortex measured by functional magnetic resonance imaging-blood oxygenation level dependent in migraine patients and healthy volunteers: pathophysiological implications.

PubMed

Martín, Helena; Sánchez del Río, Margarita; de Silanes, Carlos López; Álvarez-Linera, Juan; Hernández, Juan Antonio; Pareja, Juan A

2011-01-01

The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. To study light sensitivity and photophobia by assessing the response to light stimuli with functional magnetic resonance imaging-blood oxygenation level dependent (fMRI-BOLD) of the occipital cortex in migraineurs and in controls. Also, to try to decipher the contribution of the occipital cortex to photophobia and whether the cortical reactivity of migraineurs may be part of a constitutional (defensive) mechanism or represents an acquired (sensitization) phenomenon. Nineteen patients with migraine (7 with aura and 12 without aura) and 19 controls were studied with fMRI-BOLD during 4 increasing light intensities. Eight axial image sections of 0.5 cm that covered the occipital cortex were acquired for each intensity. We measured the extension and the intensity of activation for every light stimuli. Photophobia was estimated according to a 0 to 3 semiquantitative scale of light discomfort. Migraineurs had a significantly higher number of fMRI-activated voxels at low (320.4 for migraineurs [SD = 253.9] and 164.3 for controls [SD = 102.7], P = .027) and medium-low luminance levels (501.2 for migraineurs [SD = 279.5] and 331.1 for controls [SD = 194.3], P = .034) but not at medium-high (579.5 for migraineurs [SD = 201.4] and 510.2 for controls [SD = 239.5], P = .410) and high light stimuli (496.2 for migraineurs [SD = 216.2] and 394.7 for controls [SD = 240], P = .210). No differences were found with respect to the voxel activation intensity (amplitude of the BOLD wave) between migraineurs and controls (8.98 [SD = 2.58] vs 7.99 [SD = 2.57], P = .25; 10.82 [SD = 3.27] vs 9.81 [SD = 3.19], P = .31; 11.90 [SD = 3.18] vs 11.06 [SD = 2.56], P = .62; 11.45 [SD = 2.65] vs 10.25 [SD = 2.22], P = .16). Light discomfort was higher in the group of migraineurs at all the intensities tested, but there was no correlation with the number of activated voxels in the occipital cortex and photophobia. Repetitive light stimuli failed to demonstrate a lack of habituation in migraineurs. Migraineurs during interictal periods showed hyperxcitability of the visual cortex with a wider photoresponsive area, the underlying mechanism probably being dual: constitutional-defensive and acquired-sensitizating. © 2011 American Headache Society.

Demonstration of a light-redirecting skylight system at the Palm Springs Chamber of Commerce

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, E.S.; Beltran, L.O.; Selkowitz, S.E.

1996-05-01

As part of a demonstration project to provide a comprehensive energy upgrade to a 294 m{sup 2} (3168 ft{sup 2}) commercial building, an advanced skylight design was developed using optical light control materials and geometry to provide daylight to two adjoining offices. The skylight system was developed using outdoor physical model tests and simulation tools Limited on-site measurements and occupant polls were conducted. Market issues were addressed. The skylight systems were found to improve lighting quality and to control excessive daylight illuminance levels compared to a conventional diffusing bubble skylight. Daylighting principles developed in earlier work for vertical glazing systemsmore » (light shelves and light pipes) were shown to be applicable in skylight designs at full-scale.« less

Light harvesting control in plants.

PubMed

Ruban, Alexander V

2018-05-23

In 1991, my colleagues and I published a hypothesis article that proposed a mechanism that controls light harvesting in plants and protects them against photodamage. The major light harvesting complex, LHCII, was suggested to undergo aggregation upon exposure of the plant to damaging levels of light. Aggregated LHCII was found to be much less efficient in light harvesting, as it promptly dissipated absorbed energy into heat, possessing a very low chlorophyll fluorescence yield. Non-photochemical quenching (NPQ) is a term coined to describe this reduction in chlorophyll fluorescence yield. This article is a story of how the hypothesis that LHCII aggregation is involved in NPQ is developed into a model that is now becoming broadly accepted by the research community. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Method and system for controlling the position of a beam of light

DOEpatents

Steinkraus, Jr., Robert F.; Johnson, Gary W [Livermore, CA; Ruggiero, Anthony J [Livermore, CA

2011-08-09

An method and system for laser beam tracking and pointing is based on a conventional position sensing detector (PSD) or quadrant cell but with the use of amplitude-modulated light. A combination of logarithmic automatic gain control, filtering, and synchronous detection offers high angular precision with exceptional dynamic range and sensitivity, while maintaining wide bandwidth. Use of modulated light enables the tracking of multiple beams simultaneously through the use of different modulation frequencies. It also makes the system resistant to interfering light sources such as ambient light. Beam pointing is accomplished by feeding back errors in the measured beam position to a beam steering element, such as a steering mirror. Closed-loop tracking performance is superior to existing methods, especially under conditions of atmospheric scintillation.

Shedding Light on Nanomedicine

PubMed Central

Tong, Rong

2012-01-01

Light is electromagnetic radiation that can convert its energy into different forms (e.g., heat, chemical energy, and acoustic waves). This property has been exploited in phototherapy (e.g., photothermal therapy and photodynamic therapy) and optical imaging (e.g., fluorescence imaging) for therapeutic and diagnostic purposes. Light-controlled therapies can provide minimally or non-invasive spatiotemporal control as well as deep tissue penetration. Nanotechnology provides a numerous advantages, including selective targeting of tissues, prolongation of therapeutic effect, protection of active payloads, and improved therapeutic indices. This review explores the advances that nanotechnology can bring to light-based therapies and diagnostics, and vice versa, including photo-triggered systems, nanoparticles containing photoactive molecules, and nanoparticles that are themselves photoactive. Limitations of light-based therapies such as photic injury and phototoxicity will be discussed. PMID:22887840

High-fidelity phase and amplitude control of phase-only computer generated holograms using conjugate gradient minimisation.

PubMed

Bowman, D; Harte, T L; Chardonnet, V; De Groot, C; Denny, S J; Le Goc, G; Anderson, M; Ireland, P; Cassettari, D; Bruce, G D

2017-05-15

We demonstrate simultaneous control of both the phase and amplitude of light using a conjugate gradient minimisation-based hologram calculation technique and a single phase-only spatial light modulator (SLM). A cost function, which incorporates the inner product of the light field with a chosen target field within a defined measure region, is efficiently minimised to create high fidelity patterns in the Fourier plane of the SLM. A fidelity of F = 0.999997 is achieved for a pattern resembling an LG10 mode with a calculated light-usage efficiency of 41.5%. Possible applications of our method in optical trapping and ultracold atoms are presented and we show uncorrected experimental realisation of our patterns with F = 0.97 and 7.8% light efficiency.

Optical detector calibrator system

NASA Technical Reports Server (NTRS)

Strobel, James P. (Inventor); Moerk, John S. (Inventor); Youngquist, Robert C. (Inventor)

1996-01-01

An optical detector calibrator system simulates a source of optical radiation to which a detector to be calibrated is responsive. A light source selected to emit radiation in a range of wavelengths corresponding to the spectral signature of the source is disposed within a housing containing a microprocessor for controlling the light source and other system elements. An adjustable iris and a multiple aperture filter wheel are provided for controlling the intensity of radiation emitted from the housing by the light source to adjust the simulated distance between the light source and the detector to be calibrated. The geared iris has an aperture whose size is adjustable by means of a first stepper motor controlled by the microprocessor. The multiple aperture filter wheel contains neutral density filters of different attenuation levels which are selectively positioned in the path of the emitted radiation by a second stepper motor that is also controlled by the microprocessor. An operator can select a number of detector tests including range, maximum and minimum sensitivity, and basic functionality. During the range test, the geared iris and filter wheel are repeatedly adjusted by the microprocessor as necessary to simulate an incrementally increasing simulated source distance. A light source calibration subsystem is incorporated in the system which insures that the intensity of the light source is maintained at a constant level over time.

Synthesis of Carbon Dots with Multiple Color Emission by Controlled Graphitization and Surface Functionalization.

PubMed

Miao, Xiang; Qu, Dan; Yang, Dongxue; Nie, Bing; Zhao, Yikang; Fan, Hongyou; Sun, Zaicheng

2018-01-01

Multiple-color-emissive carbon dots (CDots) have potential applications in various fields such as bioimaging, light-emitting devices, and photocatalysis. The majority of the current CDots to date exhibit excitation-wavelength-dependent emissions with their maximum emission limited at the blue-light region. Here, a synthesis of multiple-color-emission CDots by controlled graphitization and surface function is reported. The CDots are synthesized through controlled thermal pyrolysis of citric acid and urea. By regulating the thermal-pyrolysis temperature and ratio of reactants, the maximum emission of the resulting CDots gradually shifts from blue to red light, covering the entire light spectrum. Specifically, the emission position of the CDots can be tuned from 430 to 630 nm through controlling the extent of graphitization and the amount of surface functional groups, COOH. The relative photoluminescence quantum yields of the CDots with blue, green, and red emission reach up to 52.6%, 35.1%, and 12.9%, respectively. Furthermore, it is demonstrated that the CDots can be uniformly dispersed into epoxy resins and be fabricated as transparent CDots/epoxy composites for multiple-color- and white-light-emitting devices. This research opens a door for developing low-cost CDots as alternative phosphors for light-emitting devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Addressing Challenges to the Design & Test of Operational Lighting Environments for the International Space Station

NASA Technical Reports Server (NTRS)

Clark, Toni A.

2014-01-01

In our day to day lives, the availability of light, with which to see our environment, is often taken for granted. The designers of land based lighting systems use sunlight and artificial light as their toolset. The availability of power, quantity of light sources, and variety of design options are often unlimited. The accessibility of most land based lighting systems makes it easy for the architect and engineer to verify and validate their design ideas. Failures with an implementation, while sometimes costly, can easily be addressed by renovation. Consider now, an architectural facility orbiting in space, 260 miles above the surface of the earth. This human rated architectural facility, the International Space Station (ISS) must maintain operations every day, including life support and appropriate human comforts without fail. The facility must also handle logistics of regular shipments of cargo, including new passengers. The ISS requires accommodations necessary for human control of machine systems. Additionally, the ISS is a research facility and supports investigations performed inside and outside its livable volume. Finally, the facility must support remote operations and observations by ground controllers. All of these architectural needs require a functional, safe, and even an aesthetic lighting environment. At Johnson Space Center, our Habitability and Human Factors team assists our diverse customers with their lighting environment challenges, via physical test and computer based analysis. Because of the complexity of ISS operational environment, our team has learned and developed processes that help ISS operate safely. Because of the dynamic exterior lighting environment, uses computational modeling to predict the lighting environment. The ISS' orbit exposes it to a sunrise every 90 minutes, causing work surfaces to quickly change from direct sunlight to earthshine to total darkness. Proper planning of vehicle approaches, robotics operations, and crewed Extra Vehicular Activities are mandatory to ensure safety to the crew and all others involved. Innovation in testing techniques is important as well. The advent of Solid State Lighting technology and the lack of stable national and international standards for its implementation pose new challenges on how to design, test and verify individual light fixtures and the environment that uses them. The ISS will soon be replacing its internal fluorescent lighting system to a solid state LED system. The Solid State Lighting Assembly will be used not only for general lighting, but also as a medical countermeasure to control the circadian rhythm of the crew. The new light source has performance criteria very specific to its spectral fingerprint, creating new challenges that were originally not as significant during the original design of the ISS. This presentation will showcase findings and toolsets our team is using to assist in the planning of tasks, and design of operational lighting environments on the International Space Station.

Heat meets light on the nanoscale

DOE PAGES

Boriskina, Svetlana V.; Tong, Jonathan K.; Hsu, Wei -Chun; ...

2016-06-11

We discuss the state-of-the-art and remaining challenges in the fundamental understanding and technology development for controlling light-matter interactions in nanophotonic environments in and away from thermal equilibrium. Furthermore, the topics covered range from the basics of the thermodynamics of light emission and absorption to applications in solar thermal energy generation, thermophotovoltaics, optical refrigeration, personalized cooling technologies, development of coherent incandescent light sources, and spinoptics.

40 CFR 86.1811-10 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-10 Section 86.1811-10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND...

40 CFR 86.1811-10 - Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Emission standards for light-duty vehicles, light-duty trucks and medium-duty passenger vehicles. 86.1811-10 Section 86.1811-10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND...

Evaluation of Light Attraction for the Stored-Product Psocids, Liposcelis entomophila, Liposcelis paeta, and Liposcelis brunnea.

PubMed

Diaz-Montano, John; Campbell, James F; Phillips, Thomas W; Throne, James E

2018-05-28

Psocids have become global pests of stored commodities as they can cause considerable economic losses. These insects are difficult to control because they have developed resistance to many chemical insecticides. Therefore, it is crucial to investigate alternative integrated pest management (IPM) approaches, such as the use of light attraction for monitoring and/or controlling psocids. Light attraction has been studied for Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae) but not for other psocid species. In this study, we investigated the response of adults of three psocid species (Psocoptera: Liposcelididae), Liposcelis entomophila (Enderlein), Liposcelis paeta Pearman, and Liposcelis brunnea Motschulsky, to six wavelengths of light from light-emitting diode (LED) in paired-choice pitfall tests. L. entomophila females and males were not attracted to any of the wavelengths tested. L. paeta females responded positively to two ultraviolet (UV) wavelengths (351 and 400 nm) and to green light (527 nm), while males did not respond to any light. L. brunnea females and males responded positively to all six wavelengths evaluated. Most of the LEDs that elicited positive responses to L. paeta females and L. brunnea females and males were also preferred when these lights were presented against brewer's yeast, a food attractant highly preferred by several psocid species. Females of L. paeta and L. brunnea were attracted to white light when compared with a blank, but females of L. entomophila were not attracted to white light compared to a blank.

Engineering of a green-light inducible gene expression system in Synechocystis sp. PCC6803.

PubMed

Abe, Koichi; Miyake, Kotone; Nakamura, Mayumi; Kojima, Katsuhiro; Ferri, Stefano; Ikebukuro, Kazunori; Sode, Koji

2014-03-01

In order to construct a green-light-regulated gene expression system for cyanobacteria, we characterized a green-light sensing system derived from Synechocystis sp. PCC6803, consisting of the green-light sensing histidine kinase CcaS, the cognate response regulator CcaR, and the promoter of cpcG2 (PcpcG 2 ). CcaS and CcaR act as a genetic controller and activate gene expression from PcpcG 2 with green-light illumination. The green-light induction level of the native PcpcG 2 was investigated using GFPuv as a reporter gene inserted in a broad-host-range vector. A clear induction of protein expression from native PcpcG 2 under green-light illumination was observed; however, the expression level was very low compared with Ptrc , which was reported to act as a constitutive promoter in cyanobacteria. Therefore, a Shine-Dalgarno-like sequence derived from the cpcB gene was inserted in the 5' untranslated region of the cpcG2 gene, and the expression level of CcaR was increased. Thus, constructed engineered green-light sensing system resulted in about 40-fold higher protein expression than with the wild-type promoter with a high ON/OFF ratio under green-light illumination. The engineered green-light gene expression system would be a useful genetic tool for controlling gene expression in the emergent cyanobacterial bioprocesses. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Structured light optical microscopy for three-dimensional reconstruction of technical surfaces

NASA Astrophysics Data System (ADS)

Kettel, Johannes; Reinecke, Holger; Müller, Claas

2016-04-01

In microsystems technology quality control of micro structured surfaces with different surface properties is playing an ever more important role. The process of quality control incorporates three-dimensional (3D) reconstruction of specularand diffusive reflecting technical surfaces. Due to the demand on high measurement accuracy and data acquisition rates, structured light optical microscopy has become a valuable solution to solve this problem providing high vertical and lateral resolution. However, 3D reconstruction of specular reflecting technical surfaces still remains a challenge to optical measurement principles. In this paper we present a measurement principle based on structured light optical microscopy which enables 3D reconstruction of specular- and diffusive reflecting technical surfaces. It is realized using two light paths of a stereo microscope equipped with different magnification levels. The right optical path of the stereo microscope is used to project structured light onto the object surface. The left optical path is used to capture the structured illuminated object surface with a camera. Structured light patterns are generated by a Digital Light Processing (DLP) device in combination with a high power Light Emitting Diode (LED). Structured light patterns are realized as a matrix of discrete light spots to illuminate defined areas on the object surface. The introduced measurement principle is based on multiple and parallel processed point measurements. Analysis of the measured Point Spread Function (PSF) by pattern recognition and model fitting algorithms enables the precise calculation of 3D coordinates. Using exemplary technical surfaces we demonstrate the successful application of our measurement principle.

Light-induced biochemical variations in secondary metabolite production and antioxidant activity in callus cultures of Stevia rebaudiana (Bert).

PubMed

Ahmad, Naveed; Rab, Abdur; Ahmad, Nisar

2016-01-01

Stevia rebaudiana (S. rebaudiana) is a very important species with worldwide medicinal and commercial uses. Light is one of the major elicitors that fluctuate morphogenic potential and biochemical responses. In the present study, we investigated the effect of various spectral lights on biomass accumulation and secondary metabolite production in callus cultures of S. rebaudiana. Leaf explants were placed on Murashige and Skoog (MS) medium and exposed to various spectral lights. 6-Benzyle adenine (BA) and 2, 4-dichlorophenoxy acetic acid (2, 4-D; 2.0 mgl(-1)) were used for callus induction. The control light (16/8h) produced optimum callogenic response (92.73%) than other colored lights. Compared to other colored lights, control grown cultures displayed maximum biomass accumulation (5.78 gl(-1)) during a prolonged log phase at the 18th day of growth kinetics. Cultures grown under blue light enhanced total phenolic content (TPC; 102.32 μg/g DW), total flavonoid content (TFC; 22.07 μg/g DW) and total antioxidant capacity (TAC; 11.63 μg/g DW). On the contrary, green and red lights improved reducing power assay (RPA; 0.71Fe(II)g(-1) DW) and DPPH-radical scavenging activity (DRSA; 80%). Herein, we concluded that the utilization of colored lights is a promising strategy for enhanced production of antioxidant secondary metabolites in callus cultures of S. rebaudiana. Copyright © 2015 Elsevier B.V. All rights reserved.

Monitoring and Detecting the Cigarette Beetle (Coleoptera: Anobiidae) Using Ultraviolet (LED) Direct and Reflected Lights and/or Pheromone Traps in a Laboratory and a Storehouse.

PubMed

Miyatake, Takahisa; Yokoi, Tomoyuki; Fuchikawa, Taro; Korehisa, Nobuyoshi; Kamura, Toru; Nanba, Kana; Ryouji, Shinsuke; Kamioka, Nagisa; Hironaka, Mantaro; Osada, Midori; Hariyama, Takahiko; Sasaki, Rikiya; Shinoda, Kazutaka

2016-12-01

The cigarette beetle, Lasioderma serricorne (F.), is an important stored-product pest worldwide because it damages dry foods. Detection and removal of the female L. serricorne will help to facilitate the control of the insect by removal of the egg-laying populations. In this manuscript, we examined the responses by L. serricorne to direct and reflected light in transparent cube (50 m3) set in a chamber (200 m3) and a stored facility with both direct and reflected UV-LED lights. The study also examined the responses by the beetles to light in the presence or absence of pheromone in traps that are placed at different heights. Reflected light attracted more beetles than the direct light in the experimental chamber, but the direct light traps attracted more beetles than the reflected light traps in the storehouse. Pheromone traps attracted only males; UV-LED traps attracted both sexes. The UV-LED traps with a pheromone, i.e., combined trap, attracted more males than UV-LED light traps without a pheromone, whereas the attraction of UV-LED traps with and without the pheromone was similar in females. The results suggest that UV-LED light trap combined with a sex pheromone is the best solution for monitoring and controlling L. serricorne. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Influence of Red Light Exposure at Night on Circadian Metabolism and Physiology in Sprague–Dawley Rats

PubMed Central

Dauchy, Robert T; Wren, Melissa A; Dauchy, Erin M; Hoffman, Aaron E; Hanifin, John P; Warfield, Benjamin; Jablonski, Michael R; Brainard, George C; Hill, Steven M; Mao, Lulu; Dobek, Georgina L; Dupepe, Lynell M; Blask, David E

2015-01-01

Early studies on rodents showed that short-term exposure to high-intensity light (> 70 lx) above 600 nm (red-appearing) influences circadian neuroendocrine and metabolic physiology. Here we addressed the hypothesis that long-term, low-intensity red light exposure at night (rLEN) from a ‘safelight’ emitting no light below approximately 620 nm disrupts the nocturnal circadian melatonin signal as well as circadian rhythms in circulating metabolites, related regulatory hormones, and physiologic parameters. Male Sprague–Dawley rats (n = 12 per group) were maintained on control 12:12-h light:dark (300 lx; lights on, 0600) or experimental 12:12 rLEN (8.1 lx) lighting regimens. After 1 wk, rats underwent 6 low-volume blood draws via cardiocentesis (0400, 0800, 1200, 1600, 2000, and 2400) over a 4-wk period to assess arterial plasma melatonin, total fatty acid, glucose, lactic acid, pO2, pCO2, insulin, leptin and corticosterone concentrations. Results revealed plasma melatonin levels (mean ± 1 SD) were high in the dark phase (197.5 ± 4.6 pg/mL) and low in the light phase (2.6 ± 1.2 pg/mL) of control conditions and significantly lower than controls under experimental conditions throughout the 24-h period (P < 0.001). Prominent circadian rhythms of plasma levels of total fatty acid, glucose, lactic acid, pO2, pCO2, insulin, leptin, and corticosterone were significantly (P < 0.05) disrupted under experimental conditions as compared with the corresponding entrained rhythms under control conditions. Therefore, chronic use of low-intensity rLEN from a common safelight disrupts the circadian organization of neuroendocrine, metabolic, and physiologic parameters indicative of animal health and wellbeing. PMID:25651090

Control of Adventitious Root Architecture in Rice by Darkness, Light, and Gravity1[OPEN

PubMed Central

2018-01-01

Rice (Oryza sativa) is a semiaquatic plant that is well adapted to partial flooding. Rice stems develop adventitious root (AR) primordia at each node that slowly mature but emerge only when the plant gets flooded, leading to the formation of a whole new secondary root system upon flooding. AR growth is induced by ethylene that accumulates in submerged plant tissues due to its lowered diffusion rate in water. Here, we report that the architecture of the secondary root system in flooded rice plants is controlled not only by altered gas diffusion but also by gravity and light. While ethylene promotes the emergence and growth of ARs, gravity and light determine their gravitropic setpoint angle (i.e. the deviation of growth direction relative to vertical). ARs grow upward at about 120° in the dark and downward at 54° in the light. The upward growth direction is conserved in indica and japonica rice varieties, suggestive of a conserved trait in rice. Experiments with a klinostat and with inverted stem orientation revealed that gravity promotes upward growth by about 10°. Red, far-red, and blue light lead to negative phototropism in a dose-dependent manner, with blue light being most effective, indicating that phytochrome and blue light signaling control AR system architecture. The cpt1 (coleoptile phototropism1) mutant, which lacks one of the phototropin-interacting CPT proteins, shows reduced sensitivity to blue light. Hence, the gravitropic setpoint angle of rice ARs is controlled by genetic and environmental factors that likely balance the need for oxygen supply (upward growth) with avoidance of root desiccation (downward growth). PMID:29242375

Control of Adventitious Root Architecture in Rice by Darkness, Light, and Gravity.

PubMed

Lin, Chen; Sauter, Margret

2018-02-01

Rice ( Oryza sativa ) is a semiaquatic plant that is well adapted to partial flooding. Rice stems develop adventitious root (AR) primordia at each node that slowly mature but emerge only when the plant gets flooded, leading to the formation of a whole new secondary root system upon flooding. AR growth is induced by ethylene that accumulates in submerged plant tissues due to its lowered diffusion rate in water. Here, we report that the architecture of the secondary root system in flooded rice plants is controlled not only by altered gas diffusion but also by gravity and light. While ethylene promotes the emergence and growth of ARs, gravity and light determine their gravitropic setpoint angle (i.e. the deviation of growth direction relative to vertical). ARs grow upward at about 120° in the dark and downward at 54° in the light. The upward growth direction is conserved in indica and japonica rice varieties, suggestive of a conserved trait in rice. Experiments with a klinostat and with inverted stem orientation revealed that gravity promotes upward growth by about 10°. Red, far-red, and blue light lead to negative phototropism in a dose-dependent manner, with blue light being most effective, indicating that phytochrome and blue light signaling control AR system architecture. The cpt1 ( coleoptile phototropism1 ) mutant, which lacks one of the phototropin-interacting CPT proteins, shows reduced sensitivity to blue light. Hence, the gravitropic setpoint angle of rice ARs is controlled by genetic and environmental factors that likely balance the need for oxygen supply (upward growth) with avoidance of root desiccation (downward growth). © 2018 American Society of Plant Biologists. All Rights Reserved.

Energy-Efficient and Comfortable Buildings through Multivariate Integrated Control (ECoMIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birru, Dagnachew; Wen, Yao-Jung; Rubinstein, Francis M.

2013-10-28

This project aims to develop an integrated control solution for enhanced energy efficiency and user comfort in commercial buildings. The developed technology is a zone-based control framework that minimizes energy usage while maintaining occupants’ visual and thermal comfort through control of electric lights, motorized venetian blinds and thermostats. The control framework is designed following a modular, scalable and flexible architecture to facilitate easy integration with exiting building management systems. The control framework contains two key algorithms: 1) the lighting load balancing algorithm and 2) the thermostat control algorithm. The lighting load balancing algorithm adopts a model-based closed-loop control approach tomore » determine the optimal electric light and venetian blind settings. It is formulated into an optimization problem with minimizing lighting-related energy consumptions as the objective and delivering adequate task light and preventing daylight glare as the constraints. The thermostat control algorithm is based on a well-established thermal comfort model and formulated as a root-finding problem to dynamically determine the optimal thermostat setpoint for both energy savings and improved thermal comfort. To address building-wide scalability, a system architecture was developed for the zone-based control technology. Three levels of services are defined in the architecture: external services, facility level services and zone level services. The zone-level service includes the control algorithms described above as well as the corresponding interfaces, profiles, sensors and actuators to realize the zone controller. The facility level services connect to the zones through a backbone network, handle supervisory level information and controls, and thus facilitate building-wide scalability. The external services provide communication capability to entities outside of the building for grid interaction and remote access. Various aspects of the developed control technology were evaluated and verified through both simulations and testbed implementations. Simulations coupling a DOE medium office reference building in EnergyPlus building simulation software and a prototype controller in Matlab were performed. During summer time in a mixed-humid climate zone, the simulations revealed reductions of 27% and 42% in electric lighting load and cooling load, respectively, when compared to an advanced base case with daylight dimming and blinds automatically tilted to block direct sun. Two single-room testbeds were established. The testbed at Philips Lighting business building (Rosemont, IL) was designed for quantifying energy performance of integrated controls. This particular implementation achieved 40% and 79% savings on lighting and HVAC energy, respectively, compared to a relatively simple base case operated on predefined schedules. While the resulting energy savings was very encouraging, it should be noted that there may be several caveats associated with it. 1) The test was run during late spring and early summer, and the savings numbers might not be directly used to extrapolate the annual energy savings. 2) Due to the needs for separate control and metering of the small-scale demonstrator within a large building, the HVAC system, hence the corresponding savings, did not represent a typical energy code-compliant design. 3) The light level in the control case was regulated at a particular setpoint, which was lower than then the full-on light level in the base case, and the savings resulted from tuning down the light level to the setpoint was not attributable to the contribution of the developed technology. The testbed at the Lawrence Berkeley National Laboratory (Berkeley, CA) specifically focused on glare control integration, and has demonstrated the feasibility and capability of the glare detection and prevention technique. While the short one-month test in this testbed provided a functional indication of the developed technology, and it would require at least a full solstice-to-solstice cycle to ruinously quantify the performance, which was not possible within the project timeframe. There are certain limitations inherited from the operational assumptions, which could potentially affect the effectiveness and applicability of the developed control technologies. The system takes a typical ceiling-mounting approach for the photosensor locations, and therefore, the control performance relies on proper commissioning or the built-in intelligence of the photosensor for pertinent task light level estimations. For spaces where daylight penetration diminishes significantly deeper into the zone, certain modification to the control algorithms is required to accommodate multiple lighting control subzones and the corresponding sensors for providing a more uniform light level across the entire zone. Integrated control of visual and thermal comfort requires the lighting control zone and thermal control zone to coincide with each other. In other words, the area illuminated by a lighting circuit needs to be the same area served by the thermostat. Thus, the original zoning will potentially constrain the applicability of this technology in retrofitting projects. This project demonstrated the technical feasibility of a zone-based integrated control technology. From the simulation results and testbed implementations, up to 60% lighting energy savings in daylit areas relative to a “no-controls” case can easily be achieved. A 20% reduction of whole building energy consumption is also attainable. In the aspect of occupant comfort, the testbed demonstrated the ability to maintain specified light level on the workplane while promptly mitigate daylight glare 90% of the time. The control system also managed to maintain the thermal environment at a comfortable level 90% of the time. The aspect of system scalability was guaranteed by the system architecture design, based on which the testbeds were instantiated. Analysis on the aspect of economic benefit has yielded an about 6-year payback time for a medium-sized building, including the installation of all hardware and software, such as motorized blinds and LED luminaires. The payback time can be significantly reduced if part of the hardware is already in place for retrofitting projects. It needs to be noted that since the payback analysis was partly based on the testbed performance results, it is constrained by the caveats associated with the testbed implementations. The main uncertainty lies in the contribution from the space conditioning energy savings as it was non-trivial to realistically configure a room-size HVAC system for directly extrapolating whole-building HVAC energy savings. It is recommended to further evaluate the developed technology at a larger scale, where the lighting and HVAC energy consumption can be realistically measured at the building level, to more rigorously quantify the performance potentials.« less

Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer.

PubMed

Tewolde, Fasil T; Lu, Na; Shiina, Kouta; Maruo, Toru; Takagaki, Michiko; Kozai, Toyoki; Yamori, Wataru

2016-01-01

Greenhouses with sophisticated environmental control systems, or so-called plant factories with solar light, enable growers to achieve high yields of produce with desirable qualities. In a greenhouse crop with high planting density, low photosynthetic photon flux density (PPFD) at the lower leaves tends to limit plant growth, especially in the winter when the solar altitude and PPFD at the canopy are low and day length is shorter than in summer. Therefore, providing supplemental lighting to the lower canopy can increase year-round productivity. However, supplemental lighting can be expensive. In some places, the cost of electricity is lower at night, but the effect of using supplemental light at night has not yet been examined. In this study, we examined the effects of supplemental LED inter-lighting (LED inter-lighting hereafter) during the daytime or nighttime on photosynthesis, growth, and yield of single-truss tomato plants both in winter and summer. We used LED inter-lighting modules with combined red and blue light to illuminate lower leaves right after the first anthesis. The PPFD of this light was 165 μmol m(-2) s(-1) measured at 10 cm from the LED module. LED inter-lighting was provided from 4:00 am to 4:00 pm for the daytime treatments and from 10:00 pm to 10:00 am for the nighttime treatments. Plants exposed only to solar light were used as controls. Daytime LED inter-lighting increased the photosynthetic capacity of middle and lower canopy leaves, which significantly increased yield by 27% in winter; however, photosynthetic capacity and yield were not significantly increased during summer. Nighttime LED inter-lighting increased photosynthetic capacity in both winter and summer, and yield increased by 24% in winter and 12% in summer. In addition, nighttime LED inter-lighting in winter significantly increased the total soluble solids and ascorbic acid content of the tomato fruits, by 20 and 25%, respectively. Use of nighttime LED inter-lighting was also more cost-effective than daytime inter-lighting. Thus, nighttime LED inter-lighting can effectively improve tomato plant growth and yield with lower energy cost compared with daytime both in summer and winter.

Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer

PubMed Central

Tewolde, Fasil T.; Lu, Na; Shiina, Kouta; Maruo, Toru; Takagaki, Michiko; Kozai, Toyoki; Yamori, Wataru

2016-01-01

Greenhouses with sophisticated environmental control systems, or so-called plant factories with solar light, enable growers to achieve high yields of produce with desirable qualities. In a greenhouse crop with high planting density, low photosynthetic photon flux density (PPFD) at the lower leaves tends to limit plant growth, especially in the winter when the solar altitude and PPFD at the canopy are low and day length is shorter than in summer. Therefore, providing supplemental lighting to the lower canopy can increase year-round productivity. However, supplemental lighting can be expensive. In some places, the cost of electricity is lower at night, but the effect of using supplemental light at night has not yet been examined. In this study, we examined the effects of supplemental LED inter-lighting (LED inter-lighting hereafter) during the daytime or nighttime on photosynthesis, growth, and yield of single-truss tomato plants both in winter and summer. We used LED inter-lighting modules with combined red and blue light to illuminate lower leaves right after the first anthesis. The PPFD of this light was 165 μmol m-2 s-1 measured at 10 cm from the LED module. LED inter-lighting was provided from 4:00 am to 4:00 pm for the daytime treatments and from 10:00 pm to 10:00 am for the nighttime treatments. Plants exposed only to solar light were used as controls. Daytime LED inter-lighting increased the photosynthetic capacity of middle and lower canopy leaves, which significantly increased yield by 27% in winter; however, photosynthetic capacity and yield were not significantly increased during summer. Nighttime LED inter-lighting increased photosynthetic capacity in both winter and summer, and yield increased by 24% in winter and 12% in summer. In addition, nighttime LED inter-lighting in winter significantly increased the total soluble solids and ascorbic acid content of the tomato fruits, by 20 and 25%, respectively. Use of nighttime LED inter-lighting was also more cost-effective than daytime inter-lighting. Thus, nighttime LED inter-lighting can effectively improve tomato plant growth and yield with lower energy cost compared with daytime both in summer and winter. PMID:27092163

ZnOEP based phototransistor: signal amplification and light-controlled switch.

PubMed

Ji, Heng-Xing; Hu, Jin-Song; Wan, Li-Jun

2008-06-21

A phototransistor with a field-effect transistor configuration was fabricated using a single zinc octaethylporphyrin (ZnOEP) nanorod; the device showed ability in signal amplification and reversible light-controlled switching.

Spectral and Radiometric Calibration Using Tunable Lasers

NASA Technical Reports Server (NTRS)

McCorkel, Joel (Inventor)

2017-01-01

A tunable laser system includes a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, and a controller operable to simultaneously control parameters of at least the tunable laser, the first optical parametric oscillator, and the adjustable laser cavity to produce a range of wavelengths emitted from the tunable laser system. A method of operating a tunable laser system includes using a controller to simultaneously control parameters of a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, and a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, to produce a range of wavelengths emitted from the tunable laser system.

Hybrid solar lighting systems and components

DOEpatents

Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN

2007-06-12

A hybrid solar lighting system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates each component.

Eye Disease Resulting From Increased Use of Fluorescent Lighting as a Climate Change Mitigation Strategy

PubMed Central

Walls, Kelvin L.; Benke, Geza

2011-01-01

Increased use of fluorescent lighting as a climate change mitigation strategy may increase eye disease. The safe range of light to avoid exposing the eye to potentially damaging ultraviolet (UV) radiation is 2000 to 3500K and greater than 500 nanometers. Some fluorescent lights fall outside this safe range. Fluorescent lighting may increase UV-related eye diseases by up to 12% and, according to our calculations, may cause an additional 3000 cases of cataracts and 7500 cases of pterygia annually in Australia. Greater control of UV exposure from fluorescent lights is required. This may be of particular concern for aging populations in developed countries and countries in northern latitudes where there is a greater dependence on artificial lighting. PMID:22021286

The effect of reinforcement differences on choice and response distribution during stimulus compounding.

PubMed

Bushnell, M C; Weiss, S J

1977-03-01

In Experiments I and II, rats were trained to respond on one lever during light and another during tone. The absence of tone and light controlled response cessation. In the multiple schedule of Experiment I, all reinforcements were received for responding in tone or light; in the chain schedule of Experiment II, all reinforcements were received in no tone + no light for not responding. Experiment I subjects, for which tone and light were associated with response and reinforcement increase, responded significantly more to tone-plus-light than to tone or light alone (additive summation). Experiment II subjects, for which tone and light were associated with response increase and reinforcement decrease, responded comparably to tone, light, and tone + light. Thus, additive summation was observed when stimulus-response and stimulus-reinforcer associations in tone and light were both positive, but not when they were conflicting. All subjects in both experiments responded predominantly on the light-correlated lever during tone + light, even when light intensity was reduced in testing. Furthermore, when a light was presented to a subject engaged in tone-associated responding, all subjects immediately switched the locus of responding to the light-correlated lever. No change in locus occurred when a tone was presented to a subject engaged in light-associated responding, irrespective of the stimulus-reinforcer association conditioned to tone. The light-lever preference in tone + light indicates that the heightened responding observed in Experiment I was not the summation of tone-associated behavior with light-associated behavior. Rather, it appears to be the result of a facilitation of one operant (light-associated responding) by the reinforcement-associated cue for the other.

Head-mounted LED for optogenetic experiments of freely-behaving animal

NASA Astrophysics Data System (ADS)

Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

2016-03-01

Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal characteristics of the head-mounted LED were evaluated.

LIGHT-EMITTING DIODE TECHNOLOGY IMPROVES INSECT TRAPPING

PubMed Central

GILLEN, JONATHON I.; MUNSTERMANN, LEONARD E.

2008-01-01

In a climate of increased funding for vaccines, chemotherapy, and prevention of vector-borne diseases, fewer resources have been directed toward improving disease and vector surveillance. Recently developed light-emitting diode (LED) technology was applied to standard insect-vector traps to produce a more effective lighting system. This approach improved phlebotomine sand fly capture rates by 50%, and simultaneously reduced the energy consumption by 50–60%. The LEDs were incorporated into 2 lighting designs, 1) a LED combination bulb for current light traps and 2) a chip-based LED design for a modified Centers for Disease Control and Prevention light trap. Detailed descriptions of the 2 designs are presented. PMID:18666546

Complex Light

NASA Astrophysics Data System (ADS)

Secor, Jeff; Alfano, Robert; Ashrafi, Solyman

2017-01-01

The emerging field of complex light-the study and application of custom light beams with tailored intensity, polarization or phase-is a focal point for fundamental breakthroughs in optical science. As this review will show, those advances in fundamental understanding, coupled with the latest developments in complex light generation, are translating into a range of diverse and cross-disciplinary applications that span microscopy, high-data-rate communications, optical trapping and quantum optics. We can expect more twists along the way, too, as researchers seek to manipulate and control the propagation speed of complex light beams, while others push the more exotic possibilities afforded by complex light in quantum-entanglement experiments.

Characterization of hybrid lighting systems of the Electrical Engineering Building in the Industrial University of Santander

NASA Astrophysics Data System (ADS)

Galvis, D.; Exposito, C.; Osma, G.; Amado, L.; Ordóñez, G.

2016-07-01

This paper presents an analysis of hybrid lighting systems of Electrical Engineering Building in the Industrial University of Santander, which is a pilot of green building for warm- tropical conditions. Analysis of lighting performance of inner spaces is based on lighting curves obtained from characterization of daylighting systems of these spaces. A computation tool was made in Excel-Visual Basic to simulate the behaviour of artificial lighting system considering artificial control system, user behaviour and solar condition. Also, this tool allows to estimate the electrical energy consumption of the lighting system for a day, a month and a year.

Phototaxis of Propsilocerus akamusi (Diptera: Chironomidae) From a Shallow Eutrophic Lake in Response to Led Lamps.

PubMed

Hirabayashi, Kimio; Nagai, Yoshinari; Mushya, Tetsuya; Higashino, Makoto; Taniguchi, Yoshio

2017-06-01

A study on the attraction of adult Propsilocerus akamusi midges to different-colored light traps was carried out from October 21 to November 15, 2013. The 6 colored lights used in light-emitting diode (LED) lamps were white, green, red, blue, amber, and ultraviolet (UV). The UV lamp attracted the most P. akamusi, followed by green, white, blue, amber, and red. A white pulsed LED light attracted only half the number of midges as did a continuous-emission white LED light. The result indicated that manipulation of light color, considering that the red LED light and/or pulsed LED light are not as attractive as the other colors, may be appropriate for the development of an overall integrated strategy to control nuisance P. akamusi in the Lake Suwa area.

Design and evaluation of excitation light source device for fluorescence endoscope

NASA Astrophysics Data System (ADS)

Lim, Hyun Soo

2009-06-01

This study aims at designing and evaluating light source devices that can stably generate light with various wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, and 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

Light at night disrupts nocturnal rest and elevates glucocorticoids at cool color temperatures.

PubMed

Alaasam, Valentina J; Duncan, Richard; Casagrande, Stefania; Davies, Scott; Sidher, Abhijaat; Seymoure, Brett; Shen, Yantao; Zhang, Yong; Ouyang, Jenny Q

2018-05-15

Nighttime light pollution is quickly becoming a pervasive, global concern. Since the invention and proliferation of light-emitting diodes (LED), it has become common for consumers to select from a range of color temperatures of light with varying spectra. Yet, the biological impacts of these different spectra on organisms remain unclear. We tested if nighttime illumination of LEDs, at two commercially available color temperatures (3000 and 5000 K) and at ecologically relevant illumination levels affected body condition, food intake, locomotor activity, and glucocorticoid levels in zebra finches (Taeniopygia guttata). We found that individuals exposed to 5000 K light had higher rates of nighttime activity (peaking after 1 week of treatment) compared to 3000 K light and controls (no nighttime light). Birds in the 5000 K treatment group also had increased corticosterone levels from pretreatment levels compared to 3000 K and control groups but no changes in body condition or food intake. Individuals that were active during the night did not consequently decrease daytime activity. This study adds to the growing evidence that the spectrum of artificial light at night is important, and we advocate the use of nighttime lighting with warmer color temperatures of 3000 K instead of 5000 K to decrease energetic costs for avian taxa. © 2018 Wiley Periodicals, Inc.

Integration of light and circadian signals that regulate chloroplast transcription by a nuclear-encoded sigma factor.

PubMed

Belbin, Fiona E; Noordally, Zeenat B; Wetherill, Sarah J; Atkins, Kelly A; Franklin, Keara A; Dodd, Antony N

2017-01-01

We investigated the signalling pathways that regulate chloroplast transcription in response to environmental signals. One mechanism controlling plastid transcription involves nuclear-encoded sigma subunits of plastid-encoded plastid RNA polymerase. Transcripts encoding the sigma factor SIG5 are regulated by light and the circadian clock. However, the extent to which a chloroplast target of SIG5 is regulated by light-induced changes in SIG5 expression is unknown. Moreover, the photoreceptor signalling pathways underlying the circadian regulation of chloroplast transcription by SIG5 are unidentified. We monitored the regulation of chloroplast transcription in photoreceptor and sigma factor mutants under controlled light regimes in Arabidopsis thaliana. We established that a chloroplast transcriptional response to light intensity was mediated by SIG5; a chloroplast transcriptional response to the relative proportions of red and far red light was regulated by SIG5 through phytochrome and photosynthetic signals; and the circadian regulation of chloroplast transcription by SIG5 was predominantly dependent on blue light and cryptochrome. Our experiments reveal the extensive integration of signals concerning the light environment by a single sigma factor to regulate chloroplast transcription. This may originate from an evolutionarily ancient mechanism that protects photosynthetic bacteria from high light stress, which subsequently became integrated with higher plant phototransduction networks. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Effect of ambient light on the time needed to complete a fetal biophysical profile: A randomized controlled trial.

PubMed

Said, Heather M; Gupta, Shweta; Vricella, Laura K; Wand, Katy; Nguyen, Thinh; Gross, Gilad

2017-10-01

The objective of this study is to determine whether ambient light serves as a fetal stimulus to decrease the amount of time needed to complete a biophysical profile. This is a randomized controlled trial of singleton gestations undergoing a biophysical profile. Patients were randomized to either ambient light or a darkened room. The primary outcome was the time needed to complete the biophysical profile. Secondary outcomes included total and individual component biophysical profile scores and scores less than 8. A subgroup analysis of different maternal body mass indices was also performed. 357 biophysical profile studies were analyzed. 182 studies were performed with ambient light and 175 were performed in a darkened room. There was no difference in the median time needed to complete the biophysical profile based on exposure to ambient light (6.1min in darkened room versus 6.6min with ambient light; P=0.73). No difference was found in total or individual component biophysical profile scores. Subgroup analysis by maternal body mass index did not demonstrate shorter study times with ambient light exposure in women who were normal weight, overweight or obese. Ambient light exposure did not decrease the time needed to complete the biophysical profile. There was no evidence that ambient light altered fetal behavior observed during the biophysical profile. Copyright © 2017 Elsevier B.V. All rights reserved.

Streetlight Control System Based on Wireless Communication over DALI Protocol

PubMed Central

Bellido-Outeiriño, Francisco José; Quiles-Latorre, Francisco Javier; Moreno-Moreno, Carlos Diego; Flores-Arias, José María; Moreno-García, Isabel; Ortiz-López, Manuel

2016-01-01

Public lighting represents a large part of the energy consumption of towns and cities. Efficient management of public lighting can entail significant energy savings. This work presents a smart system for managing public lighting networks based on wireless communication and the DALI protocol. Wireless communication entails significant economic savings, as there is no need to install new wiring and visual impacts and damage to the facades of historical buildings in city centers are avoided. The DALI protocol uses bidirectional communication with the ballast, which allows its status to be controlled and monitored at all times. The novelty of this work is that it tackles all aspects related to the management of public lighting: a standard protocol, DALI, was selected to control the ballast, a wireless node based on the IEEE 802.15.4 standard with a DALI interface was designed, a network layer that considers the topology of the lighting network has been developed, and lastly, some user-friendly applications for the control and maintenance of the system by the technical crews of the different towns and cities have been developed. PMID:27128923

Design of transient light signal simulator based on FPGA

NASA Astrophysics Data System (ADS)

Kang, Jing; Chen, Rong-li; Wang, Hong

2014-11-01

A design scheme of transient light signal simulator based on Field Programmable gate Array (FPGA) was proposed in this paper. Based on the characteristics of transient light signals and measured feature points of optical intensity signals, a fitted curve was created in MATLAB. And then the wave data was stored in a programmed memory chip AT29C1024 by using SUPERPRO programmer. The control logic was realized inside one EP3C16 FPGA chip. Data readout, data stream cache and a constant current buck regulator for powering high-brightness LEDs were all controlled by FPGA. A 12-Bit multiplying CMOS digital-to-analog converter (DAC) DAC7545 and an amplifier OPA277 were used to convert digital signals to voltage signals. A voltage-controlled current source constituted by a NPN transistor and an operational amplifier controlled LED array diming to achieve simulation of transient light signal. LM3405A, 1A Constant Current Buck Regulator for Powering LEDs, was used to simulate strong background signal in space. Experimental results showed that the scheme as a transient light signal simulator can satisfy the requests of the design stably.

The Influence of Low Intensities of Light Pollution on Bat Communities in a Semi-Natural Context

PubMed Central

Lacoeuilhe, Aurelie; Machon, Nathalie; Julien, Jean-François; Le Bocq, Agathe; Kerbiriou, Christian

2014-01-01

Anthropogenic light pollution is an increasingly significant issue worldwide. Over the past century, the use of artificial lighting has increased in association with human activity. Artificial lights are suspected to have substantial effects on the ecology of many species, e.g., by producing discontinuities in the territories of nocturnal animals. We analyzed the potential influence of the intensity and type of artificial light on bat activity in a semi-natural landscape in France. We used a species approach, followed by a trait-based approach, to light sensitivity. We also investigated whether the effect of light could be related to foraging traits. We performed acoustic surveys at sites located along a gradient of light intensities to assess the activity of 15 species of bats. We identified 2 functional response groups of species: one group that was light-tolerant and one group that was light-intolerant. Among the species in the latter group that appear to be disadvantaged by lighting conditions, many are rare and threatened in Europe, whereas the species from the former group are better able to thrive in disturbed habitats such as lighted areas and may actually benefit from artificial lighting. Finally, several methods of controlling light pollution are suggested for the conservation of bat communities. Recommendations for light management and the creation of dim-light corridors are proposed; these strategies may play an important role in protecting against the impact of light pollution on nocturnal animals. PMID:25360638

Light use efficiency for vegetables production in protected and indoor environments

NASA Astrophysics Data System (ADS)

Cocetta, Giacomo; Casciani, Daria; Bulgari, Roberta; Musante, Fulvio; Kołton, Anna; Rossi, Maurizio; Ferrante, Antonio

2017-01-01

In recent years, there is a growing interest for vegetables production in indoor or disadvantaged climatic zones by using greenhouses. The main problem of crop growing indoor or in environment with limited light availability is the correct choice of light source and the quality of lighting spectrum. In greenhouse and indoor cultivations, plant density is higher than in the open field and plants have to compete for light and nutrients. Nowadays, advanced systems for indoor horticulture use light emitting diodes (LED) for improving crop growth, enhancing the plant productivity and favouring the best nutritional quality formation. In closed environments, as indoor growing modules, the lighting system represents the only source of light and its features are fundamental for obtaining the best lighting performances for plant and the most efficient solution. LED lighting engines are more efficient compared to the lighting sources used traditionally in horticulture and allow light spectrum and intensity modulations to enhance the light use efficiency for plants. The lighting distribution and the digital controls are fundamental for tailoring the spectral distribution on each plant in specific moments of its growth and play an important role for optimizing growth and produce high-quality vegetables. LED lights can increase plant growth and yield, but also nutraceutical quality, since some light intensities increase pigments biosynthesis and enhance the antioxidants content of leaves or fruits: in this regards the selection of LED primary light sources in relation to the peaks of the absorbance curve of the plants is important.

The influence of low intensities of light pollution on bat communities in a semi-natural context.

PubMed

Lacoeuilhe, Aurelie; Machon, Nathalie; Julien, Jean-François; Le Bocq, Agathe; Kerbiriou, Christian

2014-01-01

Anthropogenic light pollution is an increasingly significant issue worldwide. Over the past century, the use of artificial lighting has increased in association with human activity. Artificial lights are suspected to have substantial effects on the ecology of many species, e.g., by producing discontinuities in the territories of nocturnal animals. We analyzed the potential influence of the intensity and type of artificial light on bat activity in a semi-natural landscape in France. We used a species approach, followed by a trait-based approach, to light sensitivity. We also investigated whether the effect of light could be related to foraging traits. We performed acoustic surveys at sites located along a gradient of light intensities to assess the activity of 15 species of bats. We identified 2 functional response groups of species: one group that was light-tolerant and one group that was light-intolerant. Among the species in the latter group that appear to be disadvantaged by lighting conditions, many are rare and threatened in Europe, whereas the species from the former group are better able to thrive in disturbed habitats such as lighted areas and may actually benefit from artificial lighting. Finally, several methods of controlling light pollution are suggested for the conservation of bat communities. Recommendations for light management and the creation of dim-light corridors are proposed; these strategies may play an important role in protecting against the impact of light pollution on nocturnal animals.

Tolerance of the eriophyid mite Aceria salsolae to UV-A light and implications for biological control of Russian thistle.

PubMed

Moran, Patrick J; Wibawa, M Irene; Smith, Lincoln

2017-12-01

Aceria salsolae (Acari: Eriophyidae) is being evaluated as a candidate biological control agent of Russian thistle (Salsola tragus, Chenopodiaceae), a major invasive weed of rangelands and dryland crops in the western USA. Prior laboratory host range testing under artificial lighting indicated reproduction on non-native Bassia hyssopifolia and on a native plant, Suaeda calceoliformis. However, in field tests in the native range, mite populations released on these 'nontarget' plants remained low. We hypothesized that UV-A light, which can affect behavior of tetranychid mites, would affect populations of the eriophyid A. salsolae differently on the target and nontarget plant species, decreasing the mite's realized host range. Plants were infested with A. salsolae under lamps that emitted UV-A, along with broad-spectrum lighting, and the size of mite populations and plant growth was compared to infested plants exposed only to broad-spectrum light. Russian thistle supported 3- to 55-fold larger mite populations than nontarget plants regardless of UV-A treatment. UV-A exposure did not affect mite populations on Russian thistle or S. calceoliformis, whereas it increased populations 7-fold on B. hyssopifolia. Main stems on nontarget plants grew 2- to 6-fold faster than did Russian thistle under either light treatment. The two nontarget plants attained greater volume under the control light regime than UV-A, but Russian thistle was unaffected. Although Russian thistle was always the superior host, addition of UV-A light to the artificial lighting regime did not reduce the ability of A. salsolae to reproduce on the two nontarget species, suggesting that UV-B or other environmental factors may be more important in limiting mite populations in the field.

The Effects of Light and Temperature on Biotin Synthesis in Pea Sprouts.

PubMed

Kamiyama, Shin; Ohnuki, Risa; Moriki, Aoi; Abe, Megumi; Ishiguro, Mariko; Sone, Hideyuki

2016-01-01

Biotin is an essential micronutrient, and is a cofactor for several carboxylases that are involved in the metabolism of glucose, fatty acids, and amino acids. Because plant cells can synthesize their own biotin, a wide variety of plant-based foods contains significant amounts of biotin; however, the influence of environmental conditions on the biotin content in plants remains largely unclear. In the present study, we investigated the effects of different cultivation conditions on the biotin content and biotin synthesis in pea sprouts (Pisum sativum). In the experiment, the pea sprouts were removed from their cotyledons and cultivated by hydroponics under five different lighting and temperature conditions (control [25ºC, 12-h light/12-h dark cycle], low light [25ºC, 4-h light/20-h dark cycle], dark [25ºC, 24 h dark], low temperature [12ºC, 12-h light/12-h dark cycle], and cold [6ºC, 12-h light/12-h dark cycle]) for 10 d. Compared to the biotin content of pea sprouts under the control conditions, the biotin contents of pea sprouts under the low-light, dark, and cold conditions had significantly decreased. The dark group showed the lowest biotin content among the groups. Expression of the biotin synthase gene (bio2) was also significantly decreased under the dark and cold conditions compared to the control condition, in a manner similar to that observed for the biotin content. No significant differences in the adenosine triphosphate content were observed among the groups. These results indicate that environmental conditions such as light and temperature modulate the biotin content of pea plant tissues by regulating the expression of biotin synthase.

The effect of light touch on balance control during overground walking in healthy young adults.

PubMed

Oates, A R; Unger, J; Arnold, C M; Fung, J; Lanovaz, J L

2017-12-01

Balance control is essential for safe walking. Adding haptic input through light touch may improve walking balance; however, evidence is limited. This research investigated the effect of added haptic input through light touch in healthy young adults during challenging walking conditions. Sixteen individuals walked normally, in tandem, and on a compliant, low-lying balance beam with and without light touch on a railing. Three-dimensional kinematic data were captured to compute stride velocity (m/s), relative time spent in double support (%DS), a medial-lateral margin of stability (MOS ML ) and its variance (MOS ML CV), as well as a symmetry index (SI) for the MOS ML . Muscle activity was evaluated by integrating electromyography signals for the soleus, tibialis anterior, and gluteus medius muscles bilaterally. Adding haptic input decreased stride velocity, increased the %DS, had no effect on the MOS ML magnitude, decreased the MOS ML CV, had no effect on the SI, and increased activity of most muscles examined during normal walking. During tandem walking, stride velocity and the MOS ML CV decreased, while %DS, MOS ML magnitude, SI, and muscle activity did not change with light touch. When walking on a low-lying, compliant balance beam, light touch had no effect on walking velocity, MOS ML magnitude, or muscle activity; however, the %DS increased and the MOS ML CV and SI decreased when lightly touching a railing while walking on the balance beam. The decreases in the MOS ML CV with light touch across all walking conditions suggest that adding haptic input through light touch on a railing may improve balance control during walking through reduced variability.

Way Beyond Widgets: Delivering Integrated Lighting Design in Actionable Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myer, Michael; Richman, Eric E.; Jones, Carol C.

2008-08-17

Previously, energy-efficiency strategies for commercial spaces have focused on using efficient equipment without providing specific detailed instructions. Designs by experts in their fields are an energy-efficiency product in its own right. A new national program has developed interactive application-specific lighting designs for widespread use in four major commercial sectors. This paper will describe the technical basis for the solutions, energy efficiency and cost-savings methodology, and installations and measurement/verification to-date. Lighting designs have been developed for five types of retail stores (big box, small box, grocery, specialty market, and pharmacy) and are planned for the office, healthcare, and education sectors asmore » well. Nationally known sustainable lighting designers developed the designs using high-performance commercially available products, daylighting, and lighting controls. Input and peer review was received by stakeholders, including manufacturers, architects, utilities, energy-efficiency program sponsors (EEPS), and end-users (i.e., retailers). An interactive web tool delivers the lighting solutions and analyzes anticipated energy savings using project-specific inputs. The lighting solutions were analyzed against a reference building using the space-by-space method as allowed in the Energy Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE 2004) co-sponsored by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) and the Illuminating Engineering Society of North America (IESNA). The results showed that the design vignettes ranged from a 9% to 28% reduction in the allowed lighting power density. Detailed control strategies are offered to further reduce the actual kilowatt-hour power consumption. When used together, the lighting design vignettes and control strategies show a modeled decrease in energy consumption (kWh) by 33% to 50% below the baseline design.« less

Engineering an improved light-induced dimer (iLID) for controlling the localization and activity of signaling proteins

DOE PAGES

Guntas, Gurkan; Hallett, Ryan A.; Zimmerman, Seth P.; ...

2014-12-22

The discovery of light-inducible protein–protein interactions has allowed for the spatial and temporal control of a variety of biological processes. To be effective, a photodimerizer should have several characteristics: it should show a large change in binding affinity upon light stimulation, it should not cross-react with other molecules in the cell, and it should be easily used in a variety of organisms to recruit proteins of interest to each other. In this study, to create a switch that meets these criteria we have embedded the bacterial SsrA peptide in the C-terminal helix of a naturally occurring photoswitch, the light-oxygen-voltage 2more » (LOV2) domain from Avena sativa. In the dark the SsrA peptide is sterically blocked from binding its natural binding partner, SspB. When activated with blue light, the C-terminal helix of the LOV2 domain undocks from the protein, allowing the SsrA peptide to bind SspB. Without optimization, the switch exhibited a twofold change in binding affinity for SspB with light stimulation. Here, we describe the use of computational protein design, phage display, and high-throughput binding assays to create an improved light inducible dimer (iLID) that changes its affinity for SspB by over 50-fold with light stimulation. A crystal structure of iLID shows a critical interaction between the surface of the LOV2 domain and a phenylalanine engineered to more tightly pin the SsrA peptide against the LOV2 domain in the dark. Finally, we demonstrate the functional utility of the switch through light-mediated subcellular localization in mammalian cell culture and reversible control of small GTPase signaling.« less

Adjustable task lighting: Field study assesses the benefits in an office environment.

PubMed

Joines, Sharon; James, Tamara; Liu, Siwen; Wang, Wenjiao; Dunn, Rebecca; Cohen, Shane

2015-01-01

Lighting is a part of every work task in the office environment, yet it is often overlooked. Research links direct and indirect glare to increased risk of visual discomfort among office workers with symptoms ranging from dry eyes to blurry vision or headaches. Researchers have been primarily concerned with those characteristics of task lighting that cause glare including luminance level, position (line of sight), and control. It is unknown what the benefits of adjustable task lights are and whether or not their use has an effect on musculoskeletal comfort or posture. No comprehensive field evaluations of this type were found among peer-reviewed, indexed journals. The purpose of this study was to assess the ergonomic and calculated utility power consumption benefits of adjustable LED task lighting in an office environment using a control/intervention experiment design. One hundred participants were originally recruited and randomly assigned to intervention and control groups. Self-reported data was collected on level of eye fatigue, perception of job content, intervention usability, and musculoskeletal discomfort. Data was also collected on workspace level of illumination and posture during standardized tasks (assessed using RULA). Comparing baseline data to follow-up data for the intervention group, the use of the adjustable, LED task lights provided statistically significant, positive impacts on users' rating of discomfort, eye fatigue, perception of job content, and posture between baseline and the short-term follow up. Significant benefits to musculoskeletal comfort, posture, and visual comfort were documented when participants used the adjustable task lights. Participants' assessments of the light's usability, usefulness and desirability were positive. There were no negative results found with adjustable task light use.

Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes.

PubMed

Costa-Neta, B M; da Silva, A A; Brito, J M; Moraes, J L P; Rebêlo, J M M; Silva, F S

2017-11-07

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

PubMed

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.

Eternal triangle: the interaction of light source, electrical control gear, and optics

NASA Astrophysics Data System (ADS)

S'heeren, Griet

1998-04-01

In this particular 'affair' the participants are less than human but have individual personalities they bring to their relationship with each other. High pressure metal halide lamps such as BriteArc lamps have the highest luminance and radiance of all continuously operating practical light source. Since these lamps have short arcs and are available in power ratings from about 30W to 30kW they have found applications with various optical systems. Besides the lamps, such systems include an electrical control device and an optical system. To fulfil the user's requirements for a specific application, it is not only important to choose the right lamp, but crucial to achieve a harmonious marriage between the light source, electrical control device and the optics. To run a high pressure discharge lamp an ignitor/ballast system is essential This stabilizes the lamp parameters. The chemical components inside the lamp determine the lamp voltage and the gear determines, via the current, the lamp power. These are directly related in the luminance and color temperature of the emitted light. Therefore lamp performance and effective life are dependent on the ignitor, control gear and lamp combination. Since the lamp emits radiation in all directions, collection of the light from a lamp can be improved by using reflectors to deliver the light into a lens system. Since lamps with short arc gaps approach a point source they appear ideal for optical system applications. The shape of the reflector and the focusing of the lamp determine which part of the light is collected out of the light-arc. In the case of an LCD projector, the final light output also depends on the transmission characteristics of the LCD panels. Their nonlinearity causes the color of the emitted light to be different from the lamp color. All these parameters have to be optimized to obtain the highest performance. This leads to the conclusion that a carefully matched combination of lamp, ignitor/ballast and optics should guarantee the best system performance. This paper sets out to provide some guidelines on attempting to achieve a harmonious relationship between the three partners in this particular eternal triangle.

Effects of light-emitting diode supplementary lighting on the winter growth of greenhouse plants in the Yangtze River Delta of China.

PubMed

Li, Xue; Lu, Wei; Hu, Guyue; Wang, Xiao Chan; Zhang, Yu; Sun, Guo Xiang; Fang, Zhichao

2016-12-01

The winter in the Yangtze River Delta area of China involves more than 1 month of continuous low temperature and poor light (CLTL) weather conditions, which impacts horticultural production in an unheated greenhouse; however, few greenhouses in this area are currently equipped with a heating device. The low-cost and long-living light-emitting diode (LED) was used as an artificial light source to explore the effects of supplementary lighting during the dark period in CLTL winter on the vegetative characteristics, early yield, and physiology of flowering for pepper plants grown in a greenhouse without heating. Two LED lighting sets were employed with different light source to provide 65 μmol m -2  s -1 at night: (1) LED-A: red LEDs (R, peak wavelength 660 nm) and blue LEDs (B, peak wavelength 460 nm) with an R:B ratio of 6:3; and (2) LED-B: R and B LEDs at an R:B ratio of 8:1. Plants growth parameters and chlorophyll fluorescence characteristics were compared between lighting treatments and the control group. Plants' yield and photosynthesis ability were improved by LED-A. Pepper grown under the LED-A1 strategy showed a 303.3 % greater fresh weight of fruits and a 501.3 % greater dry mass compared with the control group. Plant leaves under LED-A1 showed maximum efficiency of the light quantum yield of PSII, electron transfer rate, and the proportion of the open fraction of PSII centers, with values 113.70, 114.34, and 211.65 % higher than those of the control group, respectively, and showed the lowest rate constant of thermal energy dissipation of all groups. LED-B was beneficial to the plant height and stems diameter of the pepper plants more than LED-A. These results can serve as a guide for environment control and for realizing low energy consumption for products grown in a greenhouse in the winter in Southern China.

Optimization approach to LED crop illumination inside a controlled ecological life support system

NASA Astrophysics Data System (ADS)

Avercheva, Olga; Berkovich, Yuliy A.; Bassarskaya, Elizaveta; Zhigalova, Tatiana; Smolyanina, Svetlana O.; Kochetova, Galina; Konovalova, Irina

Artificial lighting sources for growing plants can be efficiently used to control gas exchange and preserve the necessary closure of internal matter turnover in the atmosphere of a controlled ecological life support system (CELSS). However, the lighting sources contribute strongly to the equivalent mass of a CELSS. Thus, the choice of an optimal plant lighting regime largely determines the efficiency of the artificial ecosystem. Lighting systems based on light-emitting diodes (LEDs) are now considered the most promising for space applications (Massa et al., 2006). Many types of LEDs have been developed in recent years. Because of this, the problem of optimizing a lighting source for space vegetation chambers has become more difficult: we need to optimize more parameters (such as emission spectrum, light intensity, frequency of light pulses and the shape of the lighting field inside a vegetation chamber), and in a wider range of values. In this presentation we discuss approaches to optimizing the emission spectrum of a lighting source for the use in space applications, including CELSS. One of the benefits of LEDs is their narrow-band emission spectrum, which allows us to construct a lighting source with an optimal spectrum for plant growth and production. A number of experiments have shown that the reaction of plants to a narrow-band emission spectrum of LEDs is highly species-specific and affects many processes in plants. Adding a small amount of far red light to red and blue quanta increased biomass in radish and lettuce (Tamulaitis et al., 2005). Adding blue and near UV light of different wavelengths to red light decreased total sugar content in lettuce (Urbonavičiūtė et al., 2007) and Chinese cabbage (Avercheva et al., 2009). Supplemental green light improved the nutrition quality of some lettuce varieties: decreased nitrate content and increased ascorbic acid content (Samuoliene et al., 2012). It has also been shown that changes in lighting spectrum can lead to changes in hormone content in plant tissues, and to changes in the ratio of active and inactive forms of hormones (Golovatskaya, 2005; Tamulaitis et al., 2005; Minich et al., 2006). This, in turn, may lead to changes in plant growth and biomass composition. Thus, we should vary the emission spectrum of a lighting source to improve both the productivity (i.e. gas exchange) and nutrition quality of plants growing inside a CELSS. However, it is hard to find a universal spectrum for all plants and all applications. Fundamental studies of the finer effects of narrow-band light on plant growth and metabolism may be beneficial to explain these effects. On the basis of these studies, we may be able to formulate recommendations to optimize lighting sources for different plant species. One optimization approach to LED crop illumination inside CELSS could be use of white LEDs with proper addition of red LEDs. A more difficult approach is to construct lighting sources with a multiband spectrum to adjust it for specific applications experimentally.

Controlling Light Transmission Through Highly Scattering Media Using Semi-Definite Programming as a Phase Retrieval Computation Method.

PubMed

N'Gom, Moussa; Lien, Miao-Bin; Estakhri, Nooshin M; Norris, Theodore B; Michielssen, Eric; Nadakuditi, Raj Rao

2017-05-31

Complex Semi-Definite Programming (SDP) is introduced as a novel approach to phase retrieval enabled control of monochromatic light transmission through highly scattering media. In a simple optical setup, a spatial light modulator is used to generate a random sequence of phase-modulated wavefronts, and the resulting intensity speckle patterns in the transmitted light are acquired on a camera. The SDP algorithm allows computation of the complex transmission matrix of the system from this sequence of intensity-only measurements, without need for a reference beam. Once the transmission matrix is determined, optimal wavefronts are computed that focus the incident beam to any position or sequence of positions on the far side of the scattering medium, without the need for any subsequent measurements or wavefront shaping iterations. The number of measurements required and the degree of enhancement of the intensity at focus is determined by the number of pixels controlled by the spatial light modulator.

The effect of UV light on the inactivation of Giardia lamblia and Giardia muris cysts as determined by animal infectivity assay (P-2951-01).

PubMed

Mofidi, Alexander A; Meyer, Ernest A; Wallis, Peter M; Chou, Connie I; Meyer, Barbara P; Ramalingam, Shivaji; Coffey, Bradley M

2002-04-01

This study measured the effect of germicidal ultraviolet (UV) light on Giardia lamblia and Giardia muris cysts, as determined by their infectivity in Mongolian gerbils and CD-1 mice, respectively. Reduction of cyst infectivity due to UV exposure was quantified by applying most probable number techniques. Controlled bench-scale, collimated-beam tests exposed cysts suspended in filtered natural water to light from a low-pressure UV lamp. Both G. lamblia and G. muris cysts showed similar sensitivity to UV light. At 3 mJ/cm2, a dose 10-fold lower than what large-scale UV reactors may be designed to provide, > 2-log10 (99 percent) inactivation was observed. These results, combined with previously published data showing other protozoa and bacteria have similar, high sensitivity to UV light, establish that UV disinfection of drinking water is controlled by viruses which may require over 10-fold more UV dose for the same level of control.

CMOS-compatible plenoptic detector for LED lighting applications.

PubMed

Neumann, Alexander; Ghasemi, Javad; Nezhadbadeh, Shima; Nie, Xiangyu; Zarkesh-Ha, Payman; Brueck, S R J

2015-09-07

LED lighting systems with large color gamuts, with multiple LEDs spanning the visible spectrum, offer the potential of increased lighting efficiency, improved human health and productivity, and visible light communications addressing the explosive growth in wireless communications. The control of this "smart lighting system" requires a silicon-integrated-circuit-compatible, visible, plenoptic (angle and wavelength) detector. A detector element, based on an offset-grating-coupled dielectric waveguide structure and a silicon photodetector, is demonstrated with an angular resolution of less than 1° and a wavelength resolution of less than 5 nm.

Twin-Mirrored-Galvanometer Laser-Light-Sheet Generator

NASA Technical Reports Server (NTRS)

Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Leighty, Bradley D.

1991-01-01

Multiple, rotating laser-light sheets generated to illuminate flows in wind tunnels. Designed and developed to provide flexibility and adaptability to wide range of applications. Design includes capability to control size and location of laser-light sheet in real time, to generate horizontal or vertical sheets, to sweep sheet repeatedly through volume, to generate multiple sheets with controllable separation, and to rotate single or multiple laser-light sheets. Includes electronic equipment and laser mounted on adjustable-height platform. Twin-mirrored galvanometer unit supported by tripod to reduce vibration. Other possible applications include use in construction industry to align beams of building. Artistic or display applications also possible.

[Scattered light and glare sensitivity after wavefront-guided photorefractive keratectomy (WFG-PRK) and laser in situ keratomileusis (WFG-LASIK)].

PubMed

Vignal, R; Tanzer, D; Brunstetter, T; Schallhorn, S

2008-05-01

To compare glare sensitivity measured by the intraocular scattered light between WFG-PRK and WFG-LASIK at 12 months follow-up and to assess its correlation to patients' complaints. Prospective and randomized study on 13 patients treated with WFG-LASIK, 13 patients with WFG-PRK and a control group of 35 patients. The intraocular stray light was measured by the Oculus C-Quant 12 months after surgery and before surgery for the control group. Photopic and mesopic contrast acuity and glare symptoms were reported pre- and postoperatively. Stray light values were normal in 79% of patients after WFG-LASIK and PRK and 86% in the control group, with mean values of 1.05 log, 1.03 log, and 0.99 log, respectively (p>0.05). All the patients with significant glare complaints had impaired stray light values versus 31.5% in the no-complaint group. Photopic and mesopic contrast acuity and glare symptoms were improved 1 year after surgery compared to preoperatively (no significant difference between groups). WFG-LASIK and PRK are safe and equivalent procedures regarding quality of vision. The measurement of stray light can be a discriminative test to assessing patients' glare complaints.

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)

1996-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Applications of Light Emitting Diodes in Health Care.

PubMed

Dong, Jianfei; Xiong, Daxi

2017-11-01

Light emitting diodes (LEDs) have become the main light sources for general lighting, due to their high lumen efficiency and long life time. Moreover, their high bandwidth and the availability of diverse wavelength contents ranging from ultraviolet to infrared empower them with great controllability in tuning brightness, pulse durations and spectra. These parameters are the essential ingredients of the applications in medical imaging and therapies. Despite the fast advances in both LED technologies and their applications, few reviews have been seen to link the controllable emission properties of LEDs to these applications. The objective of this paper is to bridge this gap by reviewing the main control techniques of LEDs that enable creating enhanced lighting patterns for imaging and generating effective photon doses for photobiomodulation. This paper also provides the basic mechanisms behind the effective LED therapies in treating cutaneous and neurological diseases. The emerging field of optogenetics is also discussed with a focus on the application of LEDs. The multidisciplinary topics reviewed in this paper can help the researchers in LEDs, imaging, light therapy and optogenetics better understand the basic principles in each other's field; and hence to stimulate the application of LEDs in health care.

Global Positioning System Synchronized Active Light Autonomous Docking System

NASA Technical Reports Server (NTRS)

Howard, Richard (Inventor)

1994-01-01

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Light Redirective Display Panel And A Method Of Making A Light Redirective Display Panel

DOEpatents

Veligdan, James T.

2005-07-26

An optical display panel which provides improved light intensity at a viewing angle by redirecting light emitting from the viewing screen, and a method of making a light redirective display panel, are disclosed. The panel includes an inlet face at one end for receiving light, and an outlet screen at an opposite end for displaying the light. The inlet face is defined at one end of a transparent body, which body may be formed by a plurality of waveguides, and the outlet screen is defined at an opposite end of the body. The screen includes light redirective elements at the outlet screen for re-directing light emitting from the outlet screen. The method includes stacking a plurality of glass sheets, with a layer of adhesive or epoxy between each sheet, curing the adhesive to form a stack, placing the stack against a saw and cutting the stack at two opposite ends to form a wedge-shaped panel having an inlet face and an outlet face, and forming at the outlet face a plurality of light redirective elements which direct light incident on the outlet face into a controlled light cone.

Light redirective display panel and a method of making a light redirective display panel

DOEpatents

Veligdan, James T.

2002-01-01

An optical display panel which provides improved light intensity at a viewing angle by redirecting light emitting from the viewing screen, and a method of making a light redirective display panel, are disclosed. The panel includes an inlet face at one end for receiving light, and an outlet screen at an opposite end for displaying the light. The inlet face is defined at one end of a transparent body, which body may be formed by a plurality of waveguides, and the outlet screen is defined at an opposite end of the body. The screen includes light redirective elements at the outlet screen for re-directing light emitting from the outlet screen. The method includes stacking a plurality of glass sheets, with a layer of adhesive or epoxy between each sheet, curing the adhesive to form a stack, placing the stack against a saw and cutting the stack at two opposite ends to form a wedge-shaped panel having an inlet face and an outlet face, and forming at the outlet face a plurality of light redirective elements which direct light incident on the outlet face into a controlled light cone.

A light-induced shortcut in the planktonic microbial loop

NASA Astrophysics Data System (ADS)

Ptacnik, Robert; Gomes, Ana; Royer, Sarah-Jeanne; Berger, Stella A.; Calbet, Albert; Nejstgaard, Jens C.; Gasol, Josep M.; Isari, Stamatina; Moorthi, Stefanie D.; Ptacnikova, Radka; Striebel, Maren; Sazhin, Andrey F.; Tsagaraki, Tatiana M.; Zervoudaki, Soultana; Altoja, Kristi; Dimitriou, Panagiotis D.; Laas, Peeter; Gazihan, Ayse; Martínez, Rodrigo A.; Schabhüttl, Stefanie; Santi, Ioulia; Sousoni, Despoina; Pitta, Paraskevi

2016-07-01

Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores should be regulated by light. To test this hypothesis, we incubated natural plankton from the ultra-oligotrophic Eastern Mediterranean in a set of mesocosms maintained at 4 light levels spanning a 10-fold light gradient. Picoplankton (heterotrophic bacteria (HB), pico-sized cyanobacteria, and small-sized flagellates) showed the fastest and most marked response to light, with pronounced predator-prey cycles, in the high-light treatments. Albeit cell specific activity of heterotrophic bacteria was constant across the light gradient, bacterial abundances exhibited an inverse relationship with light. This pattern was explained by light-induced top-down control of HB by bacterivorous phototrophic eukaryotes (PE), which was evidenced by a significant inverse relationship between HB net growth rate and PE abundances. Our results show that light mediates the impact of mixotrophic bacterivores. As mixo- and heterotrophs differ in the way they remineralize nutrients, these results have far-reaching implications for how nutrient cycling is affected by light.

Bright to Dim Oscillatory Response of the Neurospora Circadian Oscillator

PubMed Central

Gooch, Van D.; Johnson, Alicia E.; Larrondo, Luis F.; Loros, Jennifer J.; Dunlap, Jay C.

2014-01-01

The fungus Neurospora crassa constitutes an important model system extensively used in chronobiology. Several studies have addressed how environmental cues, such as light, can reset or synchronize a circadian system. By means of an optimized firefly luciferase reporter gene and a controllable lighting system, we show that Neurospora can display molecular circadian rhythms in dim light when cultures receive bright light prior to entering dim light conditions. We refer to this behavior as the “bright to dim oscillatory response” (BDOR). The bright light treatment can be applied up to 76 h prior to dim exposure, and it can be as short as 15 min in duration. We have characterized this response in respect to the duration of the light pulse, the time of the light pulse before dim, the intensity of dim light, and the oscillation dynamics in dim light. Although the molecular mechanism that drives the BDOR remains obscure, these findings suggest that a long-term memory of bright light exists as part of the circadian molecular components. It is important to consider the ecological significance of such dim light responses in respect to how organisms naturally maintain their timing mechanism in moonlight. PMID:24492882

Bright to dim oscillatory response of the Neurospora circadian oscillator.

PubMed

Gooch, Van D; Johnson, Alicia E; Larrondo, Luis F; Loros, Jennifer J; Dunlap, Jay C

2014-02-01

The fungus Neurospora crassa constitutes an important model system extensively used in chronobiology. Several studies have addressed how environmental cues, such as light, can reset or synchronize a circadian system. By means of an optimized firefly luciferase reporter gene and a controllable lighting system, we show that Neurospora can display molecular circadian rhythms in dim light when cultures receive bright light prior to entering dim light conditions. We refer to this behavior as the "bright to dim oscillatory response" (BDOR). The bright light treatment can be applied up to 76 h prior to dim exposure, and it can be as short as 15 min in duration. We have characterized this response in respect to the duration of the light pulse, the time of the light pulse before dim, the intensity of dim light, and the oscillation dynamics in dim light. Although the molecular mechanism that drives the BDOR remains obscure, these findings suggest that a long-term memory of bright light exists as part of the circadian molecular components. It is important to consider the ecological significance of such dim light responses in respect to how organisms naturally maintain their timing mechanism in moonlight.

Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night.

PubMed

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 (<10, 100, 300, 900 and 2700 lx) between the hours of 09:00 and 12:00 (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.

40 CFR 92.111 - Smoke measurement system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... system of the light extinction meter, as follows: ER16AP98.000 (b) Equipment. The following equipment... the exhaust plume as it passes through the optical unit. (3) Smokemeter, (light extinction meter). A... a remote control unit. (ix) Light extinction meters employing substantially identical measurement...

40 CFR 92.111 - Smoke measurement system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... system of the light extinction meter, as follows: ER16AP98.000 (b) Equipment. The following equipment... the exhaust plume as it passes through the optical unit. (3) Smokemeter, (light extinction meter). A... a remote control unit. (ix) Light extinction meters employing substantially identical measurement...

40 CFR 92.111 - Smoke measurement system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... system of the light extinction meter, as follows: ER16AP98.000 (b) Equipment. The following equipment... the exhaust plume as it passes through the optical unit. (3) Smokemeter, (light extinction meter). A... a remote control unit. (ix) Light extinction meters employing substantially identical measurement...

40 CFR 92.111 - Smoke measurement system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... system of the light extinction meter, as follows: ER16AP98.000 (b) Equipment. The following equipment... the exhaust plume as it passes through the optical unit. (3) Smokemeter, (light extinction meter). A... a remote control unit. (ix) Light extinction meters employing substantially identical measurement...

40 CFR 92.111 - Smoke measurement system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... system of the light extinction meter, as follows: ER16AP98.000 (b) Equipment. The following equipment... the exhaust plume as it passes through the optical unit. (3) Smokemeter, (light extinction meter). A... a remote control unit. (ix) Light extinction meters employing substantially identical measurement...

Hybrid solar lighting distribution systems and components

DOEpatents

Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN

2011-07-05

A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2013-12-01

The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance-Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Maximum irradiances were 1,545 mW/cm(2) (SM), 2,179 mW/cm(2) (HPM), and 4,156 mW/cm(2) (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Size variability of the unit building block of peripheral light-harvesting antennas as a strategy for effective functioning of antennas of variable size that is controlled in vivo by light intensity.

PubMed

Taisova, A S; Yakovlev, A G; Fetisova, Z G

2014-03-01

This work continuous a series of studies devoted to discovering principles of organization of natural antennas in photosynthetic microorganisms that generate in vivo large and highly effective light-harvesting structures. The largest antenna is observed in green photosynthesizing bacteria, which are able to grow over a wide range of light intensities and adapt to low intensities by increasing of size of peripheral BChl c/d/e antenna. However, increasing antenna size must inevitably cause structural changes needed to maintain high efficiency of its functioning. Our model calculations have demonstrated that aggregation of the light-harvesting antenna pigments represents one of the universal structural factors that optimize functioning of any antenna and manage antenna efficiency. If the degree of aggregation of antenna pigments is a variable parameter, then efficiency of the antenna increases with increasing size of a single aggregate of the antenna. This means that change in degree of pigment aggregation controlled by light-harvesting antenna size is biologically expedient. We showed in our previous work on the oligomeric chlorosomal BChl c superantenna of green bacteria of the Chloroflexaceae family that this principle of optimization of variable antenna structure, whose size is controlled by light intensity during growth of bacteria, is actually realized in vivo. Studies of this phenomenon are continued in the present work, expanding the number of studied biological materials and investigating optical linear and nonlinear spectra of chlorosomes having different structures. We show for oligomeric chlorosomal superantennas of green bacteria (from two different families, Chloroflexaceae and Oscillochloridaceae) that a single BChl c aggregate is of small size, and the degree of BChl c aggregation is a variable parameter, which is controlled by the size of the entire BChl c superantenna, and the latter, in turn, is controlled by light intensity in the course of cell culture growth.

Optically Tunable Resistive-Switching Memory in Multiferroic Heterostructures

NASA Astrophysics Data System (ADS)

Zheng, Ming; Ni, Hao; Xu, Xiaoke; Qi, Yaping; Li, Xiaomin; Gao, Ju

2018-04-01

Electronic phase separation has been used to realize exotic functionalities in complex oxides with external stimuli, such as magnetic field, electric field, current, light, strain, etc. Using the Nd0.7Sr0.3MnO3/0.7 Pb (Mg1 /3Nb2 /3)O3-0 .3 PbTiO3 multiferroic heterostructure as a model system, we investigate the electric field and light cocontrol of phase separation in resistive switching. The electric-field-induced nonvolatile electroresistance response is achieved at room temperature using reversible ferroelastic domain switching, which can be robustly modified on illumination of light. Moreover, the electrically controlled ferroelastic strain can effectively enhance the visible-light-induced photoresistance effect. These findings demonstrate that the electric-field- and light-induced effects strongly correlate with each other and are essentially driven by electronic phase separation. Our work opens a gate to design electrically tunable multifunctional storage devices based on multiferroic heterostructures by adding light as an extra control parameter.

Light pollution from the ground, the air and the space

NASA Astrophysics Data System (ADS)

Sánchez de Miguel, A.; Zamorano, J.; Gómez Castaño, J.; Aubé, M.; Bará, S.; Gallego, J.; Kyba, C. C. M.; Lombraña, D.; Nievas, M.; Pascual, S.; Tapia, C.

2015-05-01

The sky brightness is one of the things that most harms astronomical observation, near cities and on mountain observatories. Currently there are several initiatives to control light pollution, but the sky brightness measurements are usually local. To exercise adequate control of light pollution is necessary measurements of light pollution sources and their relation to the spatiotemporal variation of the sky brightness. We use various approaches: data taken ashore with photometers SQM and relate emissions and detected with VIIRS and DMSP satellites. We also use multispectral data taken from the International Space Station to distinguish different types of lamps that contribute to light pollution. Finally we used a spectrograph SAND for temporal analysis of the evolution of the contribution of the lights in the sky brightness of a big city like Madrid. Also we have performed a citizen science program to classify the night time images taken from the ISS (Sánchez de Miguel et al. 2014, A&G, 55, 4, 36).

Initiator and Photocatalyst-Free Visible Light Induced One-Pot Reaction: Concurrent RAFT Polymerization and CuAAC Click Reaction.

PubMed

Wang, Jie; Wang, Xinbo; Xue, Wentao; Chen, Gaojian; Zhang, Weidong; Zhu, Xiulin

2016-05-01

A new, visible light-catalyzed, one-pot and one-step reaction is successfully employed to design well-controlled side-chain functionalized polymers, by the combination of ambient temperature revisible addtion-fragmentation chain transfer (RAFT) polymerization and click chemistry. Polymerizations are well controlled in a living way under the irradiation of visible light-emitting diode (LED) light without photocatalyst and initiator, using the trithiocarbonate agent as iniferter (initiator-transfer agent-terminator) agent at ambient temperature. Fourier transfer infrared spectroscopy (FT-IR), NMR, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) data confirm the successful one-pot reaction. Compared to the reported zero-valent metal-catalyzed one-pot reaction, the polymerization rate is much faster than that of the click reaction, and the visible light-catalyzed one-pot reaction can be freely and easily regulated by turning on and off the light. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Light driven optofluidic switch developed in a ZnO-overlaid microstructured optical fiber.

PubMed

Konidakis, Ioannis; Konstantaki, Maria; Tsibidis, George D; Pissadakis, Stavros

2015-11-30

A great challenge of Optofluidics remains the control of the fluidic properties of a photonic circuit by solely utilizing light. In this study, the development of a ZnO nanolayered microstructured optical fiber (MOF) Fabry-Perot interferometer is demonstrated, along with its fully reversible optofluidic switching behaviour. The actuation and switching principle is entirely based on the employment of light sources, i.e. UV 248 nm and green 532 nm lasers, while using modest irradiation doses. The synthesized ZnO within the MOF capillaries acts as a light triggered wettability transducer, allowing the controlled water filling and draining of the MOF Fabry-Perot cavity. The progression of the optofluidic cycle is monitored in situ with optical microscopy, while Fabry-Perot reflection spectra are monitored in real time to probe temporal infiltration behaviour. Finally, a first insight on the light triggered switching mechanism, employing photoluminescence and spectrophotometric measurements is presented. Results appear highly promising towards the design of smart in-fiber optofluidic light switching devices, suitable for actuating and sensing applications.

Thioredoxins Play a Crucial Role in Dynamic Acclimation of Photosynthesis in Fluctuating Light.

PubMed

Thormählen, Ina; Zupok, Arkadiusz; Rescher, Josephin; Leger, Jochen; Weissenberger, Stefan; Groysman, Julia; Orwat, Anne; Chatel-Innocenti, Gilles; Issakidis-Bourguet, Emmanuelle; Armbruster, Ute; Geigenberger, Peter

2017-01-09

Sunlight represents the energy source for photosynthesis and plant growth. When growing in the field, plant photosynthesis has to manage strong fluctuations in light intensities. Regulation based on the thioredoxin (Trx) system is believed to ensure light-responsive control of photosynthetic reactions in the chloroplast. However, direct evidence for a role of this system in regulating dynamic acclimation of photosynthesis in fluctuating conditions is largely lacking. In this report we show that the ferredoxin-dependent Trxs m1 and m2 as well as the NADPH-dependent NTRC are both indispensable for photosynthetic acclimation in fluctuating light intensities. Arabidopsis mutants with combined deficiency in Trxs m1 and m2 show wild-type growth and photosynthesis under constant light condition, while photosynthetic parameters are strongly modified in rapidly alternating high and low light. Two independent trxm1m2 mutants show lower photosynthetic efficiency in high light, but surprisingly significantly higher photosynthetic efficiency in low light. Our data suggest that a main target of Trx m1 and m2 is the NADP-malate dehydrogenase involved in export of excess reductive power from the chloroplast. The decreased photosynthetic efficiency in the high-light peaks may thus be explained by a reduced capacity of the trxm1m2 mutants in the rapid light activation of this enzyme. In the ntrc mutant, dynamic responses of non-photochemical quenching of excitation energy and plastoquinone reduction state both were strongly attenuated in fluctuating light intensities, leading to a massive decrease in PSII quantum efficiency and a specific decrease in plant growth under these conditions. This is likely due to the decreased ability of the ntrc mutant to control the stromal NADP(H) redox poise. Taken together, our results indicate that NTRC is indispensable in ensuring the full range of dynamic responses of photosynthesis to optimize photosynthesis and maintain growth in fluctuating light, while Trxs m1 and m2 are indispensable for full activation of photosynthesis in the high-light periods but negatively affect photosynthetic efficiency in the low-light periods of fluctuating light. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

Optically controlled electrophoresis with a photoconductive substrate

NASA Astrophysics Data System (ADS)

Inami, Wataru; Nagashima, Taiki; Kawata, Yoshimasa

2018-05-01

A photoconductive substrate is used to perform electrophoresis. Light-induced micro-particle flow manipulation is demonstrated without using a fabricated flow channel. The path along which the particles were moved was formed by an illuminated light pattern on the substrate. Because the substrate conductivity and electric field distribution can be modified by light illumination, the forces acting on the particles can be controlled. This technique has potential applications as a high functionality analytical device.

National Ignition Facility main laser stray light analysis and control

DOE Office of Scientific and Technical Information (OSTI.GOV)

English, R E; Miller, J L; Peterson, G

1998-06-26

Stray light analysis has been carried out for the main laser section of the National Ignition Facility main laser section using a comprehensive non-sequential ray trace model supplemented with additional ray trace and diffraction propagation modeling. This paper describes the analysis and control methodology, gives examples of ghost paths and required tilted lenses, baffles, absorbers, and beam dumps, and discusses analysis of stray light "pencil beams" in the system.

A lighting assembly based on red and blue light-emitting diodes as a lighting source for space agriculture

NASA Astrophysics Data System (ADS)

Avercheva, Olga; Berkovich, Yuliy A.; Smolyanina, Svetlana; Bassarskaya, Elizaveta; Zhigalova, Tatiana; Ptushenko, Vasiliy; Erokhin, Alexei

Light-emitting diodes (LEDs) are a promising lighting source for space agriculture due to their high efficiency, longevity, safety, and other factors. Assemblies based on red and blue LEDs have been recommended in literature, although not all plants show sufficient productivity in such lighting conditions. Adding of green LEDs proposed in some works was aimed at psychological support for the crew, and not at the improvement of plant growth. We studied the growth and the state of the photosynthetic apparatus in Chinese cabbage (Brassica chinensis L.) plants grown under red (650 nm) and blue (470 nm) light-emitting diodes (LEDs). Plants grown under a high-pressure sodium lamp (HPS lamp) were used as a control. The plants were illuminated with two photosynthetic photon flux levels: nearly 400 µE and about 100 µE. Plants grown under LEDs with 400 µE level, as compared to control plants, showed lower fresh weight, edible biomass, growth rate, and sugar content. The difference in fresh weight and edible biomass was even more pronounced in plants grown with 100 µE level; the data indicate that the adaptability of the test plants to insufficient lighting decreased. Under LEDs, we observed the decreasing of root growth and the absence of transition to the flowering stage, which points to a change in the hormonal balance in plants grown in such lighting conditions. We also found differences in the functioning of the photosynthetic apparatus and its reaction to a low lighting level. We have concluded that a lighting assembly with red and blue LEDs only is insufficient for the plant growth and productivity, and can bring about alterations in their adaptive and regulatory mechanisms. Further studies are needed to optimize the lighting spectrum for space agriculture, taking into account the photosynthetic, phototropic and regulatory roles of light. Using white LEDs or adding far-red and green LEDs might be a promising approach.

Light colour and intensity alters reproductive/seasonal responses in Japanese quail.

PubMed

Yadav, Suneeta; Chaturvedi, Chandra Mohini

2015-08-01

An extensive literature is available on the photoperiodic responses of avian species but studies on light colour and wavelength from light emitting diode (LED) sources on reproduction are limited. Hence, an experiment was designed to study the effect of different colours and intensities of light on the reproductive responses of Japanese quail. Three-week old quail were exposed to five different light conditions with a long photoperiod (LD 16:8): WT (white fluorescent light 100 lux as control), W LED (white light emitting diode, 30 lux), B LED (blue LED, 30 lux), G LED (green LED, 30 lux) and R-LED (red LED, 30 lux). The cloacal gland size, an indicator of androgenic activity, was monitored weekly. The results indicated an early initiation of gonadal growth in WT quail which continued and maintained a plateau throughout the period of study. On the other hand, in general low intensity light, there was a decreased amplitude of the reproductive cycle and the quail exposed to different colour lights (green, red and blue lights) used different incubation times to initiate their gonadal growth and exhibited a gonadal cycle of a different duration up to 15.5 weeks. Thereafter, the gonad of quail of all the LED groups started developing again (including the blue LED exposed quail which remained undeveloped until this age) and attained the increased degree of growth until 26.5 weeks of age. During the second cycle, gonads of green and red light exposed quail continued to increase and maintained a plateau of development similar to WT exposed control while white and blue LED exposed quail exhibited spontaneous regression and attained complete sexual quiescence. Based on our study, it is suggested that long term exposure to blue LED light of low intensity may induce gonadal regression even under long-day conditions (LD 16:8), while exposure to green and red lights appears to maintain a constant photosensitivity after one complete gonadal cycle. Copyright © 2015 Elsevier Inc. All rights reserved.

Impact of red versus blue light on tolerability and efficacy of PDT: a randomized controlled trial.

PubMed

Gholam, Patrick; Bosselmann, Ina; Enk, Alexander; Fink, Christine

2018-06-01

Various light sources may be used for photodynamic therapy of actinic keratosis since photosensitizing agents are activated by different wavelengths. However, the relative impact of red and blue light irradiation on the efficacy and tolerability of therapy is controversial. The aim of this study is to compare the efficacy and tolerability of therapy with red versus blue light sources, as well as the patients' evaluation of cosmetic results, clinical response, painfulness and preferred light source for future photodynamic treatments. This is a prospective, single-center, randomized, controlled, open-label study with 28 patients undergoing elective photodynamic therapy. Red and blue light sources both showed very good results with a complete response rate of 84 % and 85 % respectively. Pain during photodynamic therapy was 6.1 vs. 5.4 (and 2.1 vs. 1.5 eight hours after therapy) on the visual analogue scale. Although these differences were statistically significant, the clinical relevance is low, since the number of therapy interruptions were equally distributed in both groups, and patients' subjective evaluation of the treatment showed no personal preference towards the light sources. Both light sources showed very good clinical results and satisfactory tolerability in this study. © 2018 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Light pollution disrupts sleep in free-living animals

PubMed Central

Raap, Thomas; Pinxten, Rianne; Eens, Marcel

2015-01-01

Artificial lighting can alter individual behaviour, with often drastic and potentially negative effects on biological rhythms, daily activity and reproduction. Whether this is caused by a disruption of sleep, an important widespread behaviour enabling animals to recover from daily stress, is unclear. We tested the hypothesis that light pollution disrupts sleep by recording individual sleep behaviour of great tits, Parus major, that were roosting in dark nest-boxes and were exposed to light-emitting diode light the following night. Their behaviour was compared to that of control birds sleeping in dark nest-boxes on both nights. Artificial lighting caused experimental birds to wake up earlier, sleep less (–5%) and spent less time in the nest-box as they left their nest-box earlier in the morning. Experimental birds did not enter the nest-box or fall asleep later than controls. Although individuals in lit nest-boxes did not wake up more often nor decreased the length of their sleep bouts, females spent a greater proportion of the night awake. Our study provides the first direct proof that light pollution has a significant impact on sleep in free-living animals, in particular in the morning, and highlights a mechanism for potential effects of light pollution on fitness. PMID:26337732

Differential responses of invasive Celastrus orbiculatus (Celastraceae) and native C. scandens to changes in light quality.

PubMed

Leicht, Stacey A; Silander, John A

2006-07-01

When plants are subjected to leaf canopy shade in forest understories or from neighboring plants, they not only experience reduced light quantity, but light quality in lowered red : far red light (R : FR). Growth and other developmental responses of plants in reduced R : FR can vary and are not consistent across species. We compared how an invasive liana, Celastrus orbiculatus, and its closely related native congener, C. scandens, responded to changes in the R : FR under controlled, simulated understory conditions. We measured a suite of morphological and growth attributes under control, neutral shading, and low R : FR light treatments. Celastrus orbiculatus showed an increase in height, aboveground biomass, and total leaf mass in reduced R : FR treatments as compared to the neutral shade, while C. scandens had increased stem diameter, single leaf area, and leaf mass to stem mass ratio. These differences provide a mechanistic understanding of the ability of C. orbiculatus to increase height and actively forage for light resources in forest understories, while C. scandens appears unable to forage for light and instead depends upon a light gap forming. The plastic growth response of C. orbiculatus in shaded conditions points to its success in forested habitats where C. scandens is largely absent.

Development of acousto-optic spatial light modulator unit for effective control of light beam intensity and diffraction angle in 3D holographic display applications

NASA Astrophysics Data System (ADS)

Kondalkar, Vijay V.; Ryu, Geonhee; Lee, Yongbeom; Lee, Keekeun

2018-07-01

An acousto-optic (AO) based holographic display unit was developed using surface acoustic wave (SAW) with different wavelength to modulate the diffraction angles, intensities, and phases of light. The new configurations were employed to control two beams simultaneously by using a single chirp inter-digital transducer (IDT), and a micro-lens array was integrated at the end of the waveguide layer to focus the diffracted light on to the screen. Two incident light beams were simultaneously modulated by using different refractive grating periods generated from chirp IDT. A diffraction angle of about 5° was obtained by using a SAW with a frequency of 430 MHz. The increase in the SAW input power enhances the diffraction efficiency of the light beam at the exit. The obtained maximum diffraction efficiency is ~70% at a frequency of 430 MHz. The sloped shape of the waveguide entrance and a tall rounded Ni poles help in coupling the incident light to the waveguide layer. The diffracted beam was collected through the lens, which increased the intensity of light in the viewing plane. COMSOL multi-physics and coupling of mode (COM) modeling were performed to predict the device performance and compared with the experimental results.

The effect of 630-nm light stimulation on the sEMG signal of forearm muscle

NASA Astrophysics Data System (ADS)

Yang, Dan D.; Hou, W. Sheng; Wu, Xiao Y.; Zheng, Xiao L.; Zheng, Jun; Jiang, Ying T.

2010-11-01

This study aimed to explore if the red light irradiation can affect the electrophysiology performance of flexor digitorum superficialis (FDS) and fatigue recovery. Four healthy volunteers were randomly divided into two groups. In the designed force-tracking tasks, all subjects performed the four fingertip isometric force production except thumb with a load of 30% of the maximum voluntary contraction (MVC) force until exhaustion. Subsequently, for the red light group, red light irradiation (640 nm wavelength, 0.23J/cm2, 20 min) was used on the right forearm; for the control group, the subjects relaxed without red light irradiation. Then subjects were required to perform fatigue trail again, and sEMG signal was collected simultaneously from FDS during finger force production. Average rectified value (ARV) and median frequency (MF) of sEMG were calculated. Compared to the control group, the red light irradiation induced more smoother value of ARV between 30% and 40%, and the value of MF was obviously large and smooth. The above electrophysiological markers indicated that recovery from muscle fatigue may be positively affected by the red light irradiation, suggesting that sEMG would become a power tool for exploring the effect of red light irradiation on local muscle fatigue.

Examination of the interaction of different lighting conditions and chronic mild stress in animal model.

PubMed

Muller, A; Gal, N; Betlehem, J; Fuller, N; Acs, P; Kovacs, G L; Fusz, K; Jozsa, R; Olah, A

2015-09-01

We examined the effects of different shift work schedules and chronic mild stress (CMS) on mood using animal model. The most common international shift work schedules in nursing were applied by three groups of Wistar-rats and a control group with normal light-dark cycle. One subgroup from each group was subjected to CMS. Levels of anxiety and emotional life were evaluated in light-dark box. Differences between the groups according to independent and dependent variables were examined with one- and two-way analysis of variance, with a significance level defined at p < 0.05. Interaction of lighting regimen and CMS was proved to be significant according to time spent in the light compartment and the average number of changes between the light and dark compartments. Results of our examination confirm that the changes of lighting conditions evocate anxiety more prominently than CMS. No significant differences were found between the results of the low rotating group and the control group, supposing that this schedule is the least harmful to health. Our results on the association between the use of lighting regimens and the level of CMS provide evidence that the fast rotating shift work schedule puts the heaviest load on the organism of animals.

Differential responses of invasive Celastrus orbiculatus (Celastraceae) and native C. scandens to changes in light quality

USGS Publications Warehouse

Leicht, S.A.; Silander, J.A.

2006-01-01

When plants are subjected to leaf canopy shade in forest understories or from neighboring plants, they not only experience reduced light quantity, but light quality in lowered red:far red light (R:FR). Growth and other developmental responses of plants in reduced R:FR can vary and are not consistent across species. We compared how an invasive liana, Celastrus orbiculatus, and its closely related native congener, C. scandens, responded to changes in the R:FR under controlled, simulated understory conditions. We measured a suite of morphological and growth attributes under control, neutral shading, and low R:FR light treatments. Celastrus orbiculatus showed an increase in height, aboveground biomass, and total leaf mass in reduced R:FR treatments as compared to the neutral shade, while C. scandens had increased stem diameter, single leaf area, and leaf mass to stem mass ratio. These differences provide a mechanistic understanding of the ability of C. orbiculatus to increase height and actively forage for light resources in forest understories, while C. scandens appears unable to forage for light and instead depends upon a light gap forming. The plastic growth response of C. orbiculatus in shaded conditions points to its success in forested habitats where C. scandens is largely absent.

The chloroplast NADPH thioredoxin reductase C, NTRC, controls non-photochemical quenching of light energy and photosynthetic electron transport in Arabidopsis.

PubMed

Naranjo, Belén; Mignée, Clara; Krieger-Liszkay, Anja; Hornero-Méndez, Dámaso; Gallardo-Guerrero, Lourdes; Cejudo, Francisco Javier; Lindahl, Marika

2016-04-01

High irradiances may lead to photooxidative stress in plants, and non-photochemical quenching (NPQ) contributes to protection against excess excitation. One of the NPQ mechanisms, qE, involves thermal dissipation of the light energy captured. Importantly, plants need to tune down qE under light-limiting conditions for efficient utilization of the available quanta. Considering the possible redox control of responses to excess light implying enzymes, such as thioredoxins, we have studied the role of the NADPH thioredoxin reductase C (NTRC). Whereas Arabidopsis thaliana plants lacking NTRC tolerate high light intensities, these plants display drastically elevated qE, have larger trans-thylakoid ΔpH and have 10-fold higher zeaxanthin levels under low and medium light intensities, leading to extremely low linear electron transport rates. To test the impact of the high qE on plant growth, we generated an ntrc-psbs double-knockout mutant, which is devoid of qE. This double mutant grows faster than the ntrc mutant and has a higher chlorophyll content. The photosystem II activity is partially restored in the ntrc-psbs mutant, and linear electron transport rates under low and medium light intensities are twice as high as compared with plants lacking ntrc alone. These data uncover a new role for NTRC in the control of photosynthetic yield. © 2015 John Wiley & Sons Ltd.

Light-evoked currents in retinal ganglion cells from dystrophic RCS rats.

PubMed

Liu, Kang; Wang, Yi; Yin, Zhengqin; Weng, Chuanhuang

2013-01-01

To study the electrophysiological properties of the light-evoked currents in ganglion cells in situations of retinal degeneration. We investigated light-evoked currents in ganglion cells by performing whole-cell patch-clamp recordings from ganglion cells using a retina-stretched preparation from Royal College of Surgeons (RCS) rats, a model of retinal degeneration and congenic controls at different ages. Pharmacological inhibitors of the AMPA receptor (NBQX), GABA receptor (BMI), and sodium channels (TTX) were used to identify the components of the light-evoked currents in ON, OFF and ON-OFF retinal ganglion cells. We found that the light-evoked currents in ganglion cells from control rats were inhibited by NBQX, BMI and TTX, suggesting that AMPA receptors, GABA receptors and sodium channels contribute to these currents in ganglion cells. However, only AMPA receptor-mediated currents were recorded in RCS rats. Light-evoked inward currents were absent in the majority of ganglion cells from RCS rats, particularly at the later stages of retinal degeneration. At earlier stages of retinal degeneration, we found that both the timing and amplitude of light-evoked currents are significantly different in ganglion cells from RCS and control rats. Our study furthers the understanding of the electrophysiological characteristics of retinal ganglion cells during retinal degeneration, and provides insight into the optimal timing for the treatment of retinal degeneration. Copyright © 2013 S. Karger AG, Basel.

Prediction of outcome of bright light treatment in patients with seasonal affective disorder: Discarding the early response, confirming a higher atypical balance, and uncovering a higher body mass index at baseline as predictors of endpoint outcome.

PubMed

Dimitrova, Tzvetelina D; Reeves, Gloria M; Snitker, Soren; Lapidus, Manana; Sleemi, Aamar R; Balis, Theodora G; Manalai, Partam; Tariq, Muhammad M; Cabassa, Johanna A; Karim, Naila N; Johnson, Mary A; Langenberg, Patricia; Rohan, Kelly J; Miller, Michael; Stiller, John W; Postolache, Teodor T

2017-11-01

We tested the hypothesis that the early improvement in mood after the first hour of bright light treatment compared to control dim-red light would predict the outcome at six weeks of bright light treatment for depressed mood in patients with Seasonal Affective Disorder (SAD). We also analyzed the value of Body Mass Index (BMI) and atypical symptoms of depression at baseline in predicting treatment outcome. Seventy-eight adult participants were enrolled. The first treatment was controlled crossover, with randomized order, and included one hour of active bright light treatment and one hour of control dim-red light, with one-hour washout. Depression was measured on the Structured Interview Guide for the Hamilton Rating Scale for Depression-SAD version (SIGH-SAD). The predictive association of depression scores changes after the first session. BMI and atypical score balance with treatment outcomes at endpoint were assessed using multivariable linear and logistic regressions. No significant prediction by changes in depression scores after the first session was found. However, higher atypical balance scores and BMI positively predicted treatment outcome. Absence of a control intervention for the six-weeks of treatment (only the first session in the laboratory was controlled). Exclusion of patients with comorbid substance abuse, suicidality and bipolar I disorder, and patients on antidepressant medications, reducing the generalizability of the study. Prediction of outcome by early response to light treatment was not replicated, and the previously reported prediction of baseline atypical balance was confirmed. BMI, a parameter routinely calculated in primary care, was identified as a novel predictor, and calls for replication and then exploration of possible mediating mechanisms. Published by Elsevier B.V.

Influence of blood contamination during multimode adhesive application on the microtensile bond strength to dentin.

PubMed

Kucukyilmaz, E; Celik, E U; Akcay, M; Yasa, B

2017-12-01

The present study evaluated the effects of blood contamination performed at different steps of bonding on the microtensile bond strength (μTBS) of multimode adhesives to dentin when using the self-etch approach. Seventy-five molars were randomly assigned to three adhesive groups comprising 25 specimens each: two multimode adhesives [Single Bond Universal (SBU) and All-Bond Universal (ABU)] and a conventional one-step self-etch adhesive [Clearfil S3 Bond Plus (CSBP)]. Each group was subdivided as follows: (1) uncontaminated (control): bonding application/light curing as a positive control; (2) contamination-1 (cont-1): bonding application/light curing/blood contamination/dry as a negative control; (3) contamination-2 (cont-2): bonding application/light curing/blood contamination/rinse/dry; (4) contamination-3 (cont-3): bonding application/blood contamination/dry/bonding re-application/light curing; and (5) contamination-4 (cont-4): bonding application/blood contamination/rinse/dry/bonding re-application/light curing. Dentin specimens were prepared for μTBS testing after the composite resin application. Data were analyzed with two-way ANOVA and post-hoc tests (α = 0.05). μTBS values were similar in cont-3 groups, and ABU/cont-4 and corresponding control groups, but were significantly lower in the other groups than in their control groups (P < 0.05). Cont-1 groups showed the lowest μTBS values (P < 0.05). Neither decontamination method prevented the decrease in μTBS when contamination occurred after light curing. Drying the blood contaminants and reapplying the adhesive may regain the dentin adhesion when contamination occurs before light curing. Alternatively, rinsing and drying contaminants followed by adhesive re-application may be effective depending on adhesive type.

A tuneable approach to uniform light distribution for artificial daylight photodynamic therapy.

PubMed

O'Mahoney, Paul; Haigh, Neil; Wood, Kenny; Brown, C Tom A; Ibbotson, Sally; Eadie, Ewan

2018-06-16

Implementation of daylight photodynamic therapy (dPDT) is somewhat limited by variable weather conditions. Light sources have been employed to provide artificial dPDT indoors, with low irradiances and longer treatment times. Uniform light distribution across the target area is key to ensuring effective treatment, particularly for large areas. A novel light source is developed with tuneable direction of light emission in order to meet this challenge. Wavelength composition of the novel light source is controlled such that the protoporphyrin-IX (PpIX) weighed spectra of both the light source and daylight match. The uniformity of the light source is characterised on a flat surface, a model head and a model leg. For context, a typical conventional PDT light source is also characterised. Additionally, the wavelength uniformity across the treatment site is characterised. The PpIX-weighted spectrum of the novel light source matches with PpIX-weighted daylight spectrum, with irradiance values within the bounds for effective dPDT. By tuning the direction of light emission, improvements are seen in the uniformity across large anatomical surfaces. Wavelength uniformity is discussed. We have developed a light source that addresses the challenges in uniform, multiwavelength light distribution for large area artificial dPDT across curved anatomical surfaces. Copyright © 2018. Published by Elsevier B.V.

Evaluating office lighting environments: Second-level analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, B.L.; Fisher, W.S.; Gillette, G.L.

1989-04-01

Data from a post-occupancy evaluation (POE) of 912 work stations with lighting power density (LPD), photometric, and occupant-response measures were examined in a detailed, second-level analysis. Seven types of lighting systems were identified with different combinations of direct and indirect ambient lighting, and task lighting and daylight. The mean illuminances at the primary task location were within the IES target values for office task with a range of mean illuminances from 32 to 75 fc, depending on the lighting system. The median LPD was about 2.36 watts/sq ft, with about one-third the work stations having LPD's at or below 2.0more » watts/sq ft. Although a majority of the occupants (69%) were satisfied about their lighting, the highest percentage of those expressing dissatisfaction (37%) with lighting had an indirect fluorescent furniture-mounted (IFFM) system. The negative reaction of so many people to the IFFM system suggests that the combination of task lighting with an indirect ambient system had an important influence on lighting satisfaction, even though task illuminances tended to be higher with the IFFM system. Concepts of lighting quality, visual health, and control were explored, as well as average luminance to explain the negative reactions to the combination of indirect lighting with furniture-mounted lighting.« less

The impacts of new street light technologies: experimentally testing the effects on bats of changing from low-pressure sodium to white metal halide

PubMed Central

Stone, Emma Louise; Wakefield, Andrew; Harris, Stephen; Jones, Gareth

2015-01-01

Artificial light at night is a major feature of anthropogenic global change and is increasingly recognized as affecting biodiversity, often negatively. On a global scale, newer technology white lights are replacing orange sodium lights to reduce energy waste. In 2009, Cornwall County Council (UK) commenced replacement of existing low-pressure sodium (LPS) high intensity discharge (HID) street lights with new Phillips CosmoPolis white ceramic metal halide street lights to reduce energy wastage. This changeover provided a unique collaborative opportunity to implement a before-after-control-impact field experiment to investigate the ecological effects of newly installed broad spectrum light technologies. Activity of the bat species Pipistrellus pipistrellus, P. pygmaeus and Nyctalus/Eptesicus spp. was significantly higher at metal halide than LPS lights, as found in other studies of bat activity at old technology (i.e. mercury vapour) white light types. No significant difference was found in feeding attempts per bat pass between light types, though more passes overall were recorded at metal halide lights. Species-specific attraction of bats to the metal halide lights could have cascading effects at lower trophic levels. We highlight the need for further research on possible ecosystem-level effects of light technologies before they are installed on a wide scale. PMID:25780239

Nocturnal illumination maintains reproductive function and simulates the period-lengthening effect of constant light in the mature male Djungarian hamster (Phodopus sungorus)

NASA Technical Reports Server (NTRS)

Ferraro, J. S.

1990-01-01

Mature male Djungarian hamsters (Phodopus sungorus) were placed in individual light-tight, sound attenuated chambers and exposed to one of four lighting conditions for a duration of approximately seven weeks. The four lighting conditions were: constant light (LL); constant dark (DD); feedback lighting (LDFB; a condition that illuminates the cage in response to locomotor activity); or a feedback lighting neighbor control (LDFB NC; the animal receives the same light pattern as a paired animal in feedback lighting, but has no control over it). Exposure of hamsters to LL or LDFB produced significantly and similarly longer free-running periods of the locomotor activity rhythm than exposure of animals to DD. Hamsters exposed to LDFB NC did not free-run or entrain, but rather displayed "relative coordination". The paired testes and sex accessory glands weights suggest that in the Djungarian hamster, LL and LDFB exposed animals maintained reproductive function, whereas DD exposed animals did not. Animals exposed to LDFB NC had intermediate paired testes weights. Since several previous studies have demonstrated that short pulses of light, which are coincident with the subjective night, are photostimulatory, it is not surprising that LDFB maintained reproductive function in the mature Djungarian hamster. Feedback lighting, however, has been shown to be an insufficient stimulus to maintain reproductive function of mature male and female Syrian hamsters, and to the reproductive maturation of immature Djungarian hamsters. The results suggest that there may be slight, but significant differences in the way these two species interpret photoperiod, as well as a developmental change in the photoperiodic response of Djungarian hamsters.

Substrain and light regime effects on integrated anxiety-related behavioral z-scores in male C57BL/6 mice-Hypomagnesaemia has only a small effect on avoidance behavior.

PubMed

Labots, M; Zheng, X; Moattari, G; Lozeman-Van't Klooster, J G; Baars, J M; Hesseling, P; Lavrijsen, M; Kirchhoff, S; Ohl, F; van Lith, H A

2016-06-01

Magnesium (Mg) has been described to possess an anxiolytic function, but a number of studies present inconsistent results on this matter. In this study the effect of Mg deficiency on anxiety-related behavior, brain and blood plasma Mg in young adult male C57BL/6JOlaHsd and C57BL/6NCrl mice was studied. The animals were put on a control or Mg deficient diet from day 0 and significant hypomagnesaemia was evident from day 12 onwards in the test animals. Housing and test conditions were under either conventional light regime (white light behavioral test conditions) or reverse light regime (red light behavioral test conditions). The animals were tested in three tests for unconditioned anxiety: the modified Hole Board (day 14), the light-dark test (day 21) and the elevated plus maze (day 28). Overall integrated behavioral z-scores were calculated over these three behavioral tests. Mg showed a structure dependent distribution at the level of the brain, that differed between C57BL/6 substrain and light regime (conventional versus reverse), respectively. Likewise, total brain Mg did differ between substrain and light regime, but was not affected by the diet. Animals on the Mg deficient diet housed under conventional light regime had a higher final (day 28) blood plasma corticosterone level as compared to controls. Animals housed under reverse light regime exhibited no diet effect of plasma corticosterone levels. The significant hypomagnesaemia at blood plasma level resulted in an effect of Mg deficiency on avoidance, but not overall anxiety-related behavior. Significant differences regarding avoidance behavior were found between the two substrains and light regimes, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Size-controllable nanopyramids photonic crystal selectively grown on p-GaN for enhanced light-extraction of light-emitting diodes.

PubMed

Du, Chengxiao; Wei, Tongbo; Zheng, Haiyang; Wang, Liancheng; Geng, Chong; Yan, Qingfeng; Wang, Junxi; Li, Jinmin

2013-10-21

Size-controllable p-GaN hexagonal nanopyramids (HnPs)-photonic crystal (PhC) structures were selectively grown on flat p-GaN layer for the elimination of total internal reflection of light-emitting diodes (LEDs). The LEDs with HnPs-PhC of 46.3% bottom fill factor (PhC lattice constant is 730 nm) showed an improved light output power by 99.9% at forward current of 350 mA compared to the reference LEDs with flat p-GaN layer. We confirmed the effect of HnPs-PhC with different bottom fill factors and the effect of nanopyramid-shaped and nanocolumn-shaped PhC on the light-extraction of LEDs was also investigated by using three-dimensional finite-difference time-domain simulations.

Quantum enhanced feedback cooling of a mechanical oscillator using nonclassical light.

PubMed

Schäfermeier, Clemens; Kerdoncuff, Hugo; Hoff, Ulrich B; Fu, Hao; Huck, Alexander; Bilek, Jan; Harris, Glen I; Bowen, Warwick P; Gehring, Tobias; Andersen, Ulrik L

2016-11-29

Laser cooling is a fundamental technique used in primary atomic frequency standards, quantum computers, quantum condensed matter physics and tests of fundamental physics, among other areas. It has been known since the early 1990s that laser cooling can, in principle, be improved by using squeezed light as an electromagnetic reservoir; while quantum feedback control using a squeezed light probe is also predicted to allow improved cooling. Here we show the implementation of quantum feedback control of a micro-mechanical oscillator using squeezed probe light. This allows quantum-enhanced feedback cooling with a measurement rate greater than it is possible with classical light, and a consequent reduction in the final oscillator temperature. Our results have significance for future applications in areas ranging from quantum information networks, to quantum-enhanced force and displacement measurements and fundamental tests of macroscopic quantum mechanics.

A design of calibration single star simulator with adjustable magnitude and optical spectrum output system

NASA Astrophysics Data System (ADS)

Hu, Guansheng; Zhang, Tao; Zhang, Xuan; Shi, Gentai; Bai, Haojie

2018-03-01

In order to achieve multi-color temperature and multi-magnitude output, magnitude and temperature can real-time adjust, a new type of calibration single star simulator was designed with adjustable magnitude and optical spectrum output in this article. xenon lamp and halogen tungsten lamp were used as light source. The control of spectrum band and temperature of star was realized with different multi-beam narrow band spectrum with light of varying intensity. When light source with different spectral characteristics and color temperature go into the magnitude regulator, the light energy attenuation were under control by adjusting the light luminosity. This method can completely satisfy the requirements of calibration single star simulator with adjustable magnitude and optical spectrum output in order to achieve the adjustable purpose of magnitude and spectrum.

The implementation of intelligent home controller

NASA Astrophysics Data System (ADS)

Li, Biqing; Li, Zhao

2018-04-01

This paper mainly talks about the working way of smart home terminal controller and the design of hardware and software. Controlling the lights and by simulating the lamp and the test of the curtain, destroy the light of lamp ON-OFF and the curtain's UP-DOWN by simulating the lamp and the test of the cuetain. Through the sensor collects the ambient information and sends to the network, such as light, temperature and humidity. Besides, it can realise the control of intelligent home control by PCS. Terminal controller of intelligent home which is based on ZiBee technology has into the intelligent home system, it provides people with convenient, safe and intelligent household experience.

Detonation control

DOEpatents

Mace, Jonathan L.; Seitz, Gerald J.; Bronisz, Lawrence E.

2016-10-25

Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.

Efficiency Evaluation of Nozawa-Style Black Light Trap for Control of Anopheline Mosquitoes

PubMed Central

Lee, Hee Il; Seo, Bo Youl; Shin, E-Hyun; Burkett, Douglas A.; Lee, Jong-Koo

2009-01-01

House-residual spraying and insecticide-treated bed nets have achieved some success in controlling anthropophilic and endophagic vectors. However, these methods have relatively low efficacy in Korea because Anopheles sinensis, the primary malaria vector, is highly zoophilic and exophilic. So, we focused our vector control efforts within livestock enclosures using ultraviolet black light traps as a mechanical control measure. We found that black light traps captured significantly more mosquitoes at 2 and 2.5 m above the ground (P < 0.05). We also evaluated the effectiveness of trap spacing within the livestock enclosure. In general, traps spaced between 4 and 7 m apart captured mosquitoes more efficiently than those spaced closer together (P > 0.05). Based on these findings, we concluded that each black light trap in the livestock enclosures killed 7,586 female mosquitoes per trap per night during the peak mosquito season (July-August). In May-August 2003, additional concurrent field trials were conducted in Ganghwa county. We got 74.9% reduction (P < 0.05) of An. sinensis in human dwellings and 61.5% reduction (P > 0.05) in the livestock enclosures. The black light trap operation in the livestock enclosures proved to be an effective control method and should be incorporated into existing control strategies in developed countries. PMID:19488423

Serum neurofilament as a predictor of disease worsening and brain and spinal cord atrophy in multiple sclerosis.

PubMed

Barro, Christian; Benkert, Pascal; Disanto, Giulio; Tsagkas, Charidimos; Amann, Michael; Naegelin, Yvonne; Leppert, David; Gobbi, Claudio; Granziera, Cristina; Yaldizli, Özgür; Michalak, Zuzanna; Wuerfel, Jens; Kappos, Ludwig; Parmar, Katrin; Kuhle, Jens

2018-05-30

Neuro-axonal injury is a key factor in the development of permanent disability in multiple sclerosis. Neurofilament light chain in peripheral blood has recently emerged as a biofluid marker reflecting neuro-axonal damage in this disease. We aimed at comparing serum neurofilament light chain levels in multiple sclerosis and healthy controls, to determine their association with measures of disease activity and their ability to predict future clinical worsening as well as brain and spinal cord volume loss. Neurofilament light chain was measured by single molecule array assay in 2183 serum samples collected as part of an ongoing cohort study from 259 patients with multiple sclerosis (189 relapsing and 70 progressive) and 259 healthy control subjects. Clinical assessment, serum sampling and MRI were done annually; median follow-up time was 6.5 years. Brain volumes were quantified by structural image evaluation using normalization of atrophy, and structural image evaluation using normalization of atrophy, cross-sectional, cervical spinal cord volumes using spinal cord image analyser (cordial). Results were analysed using ordinary linear regression models and generalized estimating equation modelling. Serum neurofilament light chain was higher in patients with a clinically isolated syndrome or relapsing remitting multiple sclerosis as well as in patients with secondary or primary progressive multiple sclerosis than in healthy controls (age adjusted P < 0.001 for both). Serum neurofilament light chain above the 90th percentile of healthy controls values was an independent predictor of Expanded Disability Status Scale worsening in the subsequent year (P < 0.001). The probability of Expanded Disability Status Scale worsening gradually increased by higher serum neurofilament light chain percentile category. Contrast enhancing and new/enlarging lesions were independently associated with increased serum neurofilament light chain (17.8% and 4.9% increase per lesion respectively; P < 0.001). The higher the serum neurofilament light chain percentile level, the more pronounced was future brain and cervical spinal volume loss: serum neurofilament light chain above the 97.5th percentile was associated with an additional average loss in brain volume of 1.5% (P < 0.001) and spinal cord volume of 2.5% over 5 years (P = 0.009). Serum neurofilament light chain correlated with concurrent and future clinical and MRI measures of disease activity and severity. High serum neurofilament light chain levels were associated with both brain and spinal cord volume loss. Neurofilament light chain levels are a real-time, easy to measure marker of neuro-axonal injury that is conceptually more comprehensive than brain MRI.

Blue light versus red light for photodynamic therapy of basal cell carcinoma in patients with Gorlin syndrome: A bilaterally controlled comparison study.

PubMed

Maytin, Edward V; Kaw, Urvashi; Ilyas, Muneeb; Mack, Judith A; Hu, Bo

2018-06-01

Photodynamic therapy (PDT) is a non-scarring alternative for treating basal cell carcinoma (BCC) in patients with Basal Cell Nevus Syndrome (BCNS), also known as Gorlin syndrome. In Europe, red light (635 nm) is the predominant source for PDT, whereas in the United States blue light (400 nm) is more widely available. The objective of this study was to conduct a head-to-head comparison of blue light and red light PDT in the same BCNS patients. In a pilot study of three patients with 141 BCC lesions, 5-aminolevulinate (20% solution) was applied to all tumors. After 4 h, half of the tumors were illuminated with blue light and the remainder with red light. To ensure safety while treating this many tumors simultaneously, light doses were escalated gradually. Six treatments were administered in three biweekly sessions over 4 months, with a final evaluation at 6 months. Tumor status was documented with high-resolution photographs. Persistent lesions were biopsied at 6 months. Clearance rates after blue light (98%) were slightly better than after red light (93%), with blue light shown to be statistically non-inferior to red light. Eight suspicious lesions were biopsied, 5 after red light (5/5 were BCC) and 3 after blue light (1 was BCC). Blue light PDT was reportedly less painful. Blue light and red light PDT appear to be equally safe and perhaps equally effective for treating BCC tumors in BCNS patients. Further studies to evaluate long-term clearance after blue light PDT are needed. Copyright © 2018 Elsevier B.V. All rights reserved.

Delay of constant light-induced persistent vaginal estrus by 24-hour time cues in rats.

PubMed

Weber, A L; Adler, N T

1979-04-20

The normal ovarian cycle of female rats is typically replaced by persistent estrus when these animals are housed under constant light. Evidence presented here shows that the maintenance of periodicity in the environment can at least delay (if not prevent) the photic induction of persistent vaginal estrus. Female rats in constant light were exposed to vaginal smearing at random times or at the same time every day. In another experiment, female rats were exposed to either constant bright light, constant dim light, or a 24-hour photic cycle of bright and dim light. The onset of persistent vaginal estrus was delayed in rats exposed to 24-hour time cues even though the light intensities were the same as or greater than those for the aperiodic control groups. The results suggest that the absence of 24-hour time cues in constant light contributes to the induction of persistent estrus.

Adult Pacific Oyster (Crassostrea gigas) May Have Light Sensitivity

PubMed Central

Yang, Yanjian; Li, Zhuang; Guo, Ting; Li, Yongchuan; Wang, Xiaotong

2015-01-01

Light-sensitivity is an important aspect of mollusk survival as it plays a vital role in reproduction and predator avoidance. In the Pacific oyster Crassostrea gigas light sensitivity has been demonstrated in the larval stage but has not yet been conclusively demonstrated in adult oysters. In this paper we describe an experiment which was undertaken to determine if adult Pacific oysters were sensitive to light. One LED flashlight was used to shine light onto adult oysters while they were filtering seawater through their shell openings. We found that the degree of opening increased gradually during the light period but rapidly decreased when the flashlight was turned off in the treated group but not in the control group. These results suggest that adult Pacific oyster may be sensitive to light. PMID:26474058

Light use study for vertical channelization devices

DOT National Transportation Integrated Search

2003-05-01

Although the Manual on Uniform Traffic Control Devices (MUTCD) does not require the use of warning lights on channelization devices, the Arizona Department of Transportation (ADOT) has historically required their use on all traffic control devices us...

Effect of red and blue light emitting diodes "CRB-LED" on in vitro organogenesis of date palm (Phoenix dactylifera L.) cv. Alshakr.

PubMed

Al-Mayahi, Ahmed Madi Waheed

2016-10-01

The objective of the present study is to determine the effect of light source on enhancement of shoot multiplication, phytochemicals, as well as, antioxidant enzyme activities of in vitro cultures of date palm cv. Alshakr. In vitro-grown buds were cultured on Murashige and Skoog (MS) medium and incubated under a conventional white fluorescent light (control), and combinations of red + blue light emitting diode (18:2) (CRB-LED). Results revealed that the treatment of CRB-LED showed a significant increase in the number of shoots compared with the white florescent light. Total soluble carbohydrate "TSCH" (7.10 mg g(-1) DW.), starch (1.63 mg g(-1) DW.) and free amino acids (2.90 mg g(-1) DW.) were significantly higher in CRB-LED (p < 0.05). Additionally, CRB-LED induced a higher peroxidase activity (25.50 U ml(-1)) compared with the white fluorescent light treatment (19.74 U ml(-1)) as control treatment. Potassium, magnesium and sodium contents in (3.62, 13.99 and 2.76 mg g(-1) DW.) were increased in in vitro shoots under CRB-LED treatment in comparison with fluorescent light (p < 0.05). Protein profile showed the appearance of newly bands with the molecular weight of 38 and 60 kDa at the treatment CRB-LED compared with control treatment. Our results demonstrate the positive effects of CRB-LED light during the course of date palm tissue cultures.

Effect of Age and Glaucoma on the Detection of Darks and Lights

PubMed Central

Zhao, Linxi; Sendek, Caroline; Davoodnia, Vandad; Lashgari, Reza; Dul, Mitchell W.; Zaidi, Qasim; Alonso, Jose-Manuel

2015-01-01

Purpose We have shown previously that normal observers detect dark targets faster and more accurately than light targets, when presented in noisy backgrounds. We investigated how these differences in detection time and accuracy are affected by age and ganglion cell pathology associated with glaucoma. Methods We asked 21 glaucoma patients, 21 age-similar controls, and 5 young control observers to report as fast as possible the number of 1 to 3 light or dark targets. The targets were positioned at random in a binary noise background, within the central 30° of the visual field. Results We replicate previous findings that darks are detected faster and more accurately than lights. We extend these findings by demonstrating that differences in detection of darks and lights are found reliably across different ages and in observers with glaucoma. We show that differences in detection time increase at a rate of approximately 55 msec/dB at early stages of glaucoma and then remain constant at later stages at approximately 800 msec. In normal subjects, differences in detection time increase with age at a rate of approximately 8 msec/y. We also demonstrate that the accuracy to detect lights and darks is significantly correlated with the severity of glaucoma and that the mean detection time is significantly longer for subjects with glaucoma than age-similar controls. Conclusions We conclude that differences in detection of darks and lights can be demonstrated over a wide range of ages, and asymmetries in dark/light detection increase with age and early stages of glaucoma. PMID:26513506