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Sample records for fluorescent lighting product

  1. NEXT GENERATION ENERGY EFFICIENT FLUORESCENT LIGHTING PRODUCT

    SciTech Connect

    Alok Srivastava; Anant Setlur

    2003-04-01

    This is the Final Report of the Next-Generation Energy Efficient Fluorescent Lighting Products program, Department of Energy (DOE). The overall goal of this three-year program was to develop novel phosphors to improve the color rendition and efficiency of compact and linear fluorescent lamps. The prime technical approach was the development of quantum-splitting phosphor (QSP) to further increase the efficiency of conventional linear fluorescent lamps and the development of new high color rendering phosphor blends for compact fluorescent lamps (CFLs) as potential replacements for the energy-hungry and short-lived incandescent lamps in market segments that demand high color rendering light sources. We determined early in the project that the previously developed oxide QSP, SrAl{sub 12}O{sub 19}:Pr{sup 3+}, did not exhibit an quantum efficiency higher than unity under excitation by 185 nm radiation, and we therefore worked to determine the physical reasons for this observation. From our investigations we concluded that the achievement of quantum efficiency exceeding unity in SrAl{sub 12}O{sub 19}:Pr{sup 3+} was not possible due to interaction of the Pr{sup 3+} 5d level with the conduction band of the solid. The interaction which gives rise to an additional nonradiative decay path for the excitation energy is responsible for the low quantum efficiency of the phosphor. Our work has led to the development of a novel spectroscopic method for determining photoionzation threshold of luminescent centers in solids. This has resulted in further quantification of the requirements for host phosphor lattice materials to optimize quantum efficiency. Because of the low quantum efficiency of the QSP, we were unable to demonstrate a linear fluorescent lamp with overall performance exceeding that of existing mercury-based fluorescent lamps. Our work on the high color rendering CFLs has been very successful. We have demonstrated CFLs that satisfies the EnergyStar requirement with color

  2. Shelf life of fresh meat products under LED or fluorescent lighting.

    PubMed

    Steele, K S; Weber, M J; Boyle, E A E; Hunt, M C; Lobaton-Sulabo, A S; Cundith, C; Hiebert, Y H; Abrolat, K A; Attey, J M; Clark, S D; Johnson, D E; Roenbaugh, T L

    2016-07-01

    Enhanced pork loin chops, beef longissimus lumborum steaks, semimembranosus steaks (superficial and deep portions), ground beef, and ground turkey were displayed under light emitting diode (LED) and fluorescent (FLS) lighting in two multi-shelf, retail display cases with identical operating parameters. Visual and instrumental color, internal product temperature, case temperature, case cycling, thiobarbituric acid reactive substances (TBARS), and Enterobacteriaceae and aerobic plate counts were evaluated. Under LED, beef products (except the deep portion of beef semimembranosus steaks) showed less (P<0.05) visual discoloration. Pork loin chops had higher (P<0.05) L* values for LED lighting. Other than beef longissimus lumborum steaks, products displayed under LED lights had colder internal temperatures than products under FLS lights (P<0.05). Under LED, pork loin chops, ground turkey, and beef semimembranosus steaks had higher (P<0.05) values for TBARS. LED provides colder case and product temperatures, more case efficiency, and extended color life by at least 0.5d for longissimus and semimembranosus steaks; however, some LED cuts showed increased lipid oxidation.

  3. Shedding Some Light on Fluorescent Bulbs.

    ERIC Educational Resources Information Center

    Guilbert, Nicholas R.

    1996-01-01

    Explores some of the principles behind the working of fluorescent bulbs using a specially prepared fluorescent bulb with the white inner fluorescent coating applied along only half its length. Discusses the spectrum, the bulb plasma, and light production. (JRH)

  4. Fluorescence and Light Scattering

    ERIC Educational Resources Information Center

    Clarke, Ronald J.; Oprysa, Anna

    2004-01-01

    The aim of the mentioned experiment is to aid students in developing tactics for distinguishing between signals originating from fluorescence and light scattering. Also, the experiment provides students with a deeper understanding of the physicochemical bases of each phenomenon and shows that the techniques are actually related.

  5. Effect of light-emitting diode vs. fluorescent lighting on laying hens in aviary hen houses: Part 1 - Operational characteristics of lights and production traits of hens.

    PubMed

    Long, H; Zhao, Y; Wang, T; Ning, Z; Xin, H

    2016-01-01

    Light-emitting diode (LED) lights are becoming more affordable for agricultural applications. Despite many lab-scale studies concerning impact of LED on poultry, little research has been documented under field production conditions, especially for laying hens. This 15-month field study was carried out to evaluate the effects of LED vs. fluorescent (FL) lights on laying hens (Dekalb white breed) using 4 (2 pairs) aviary hen houses each at a nominal capacity of 50,000 hens. The evaluation was done regarding operational characteristics of the lights and hen production traits. The results show that spatial distribution of the LED light was less uniform than that of the FL light. Light intensity of the LED light decreased by 27% after 3,360 h use but remained quite steady from 3,360 to 5,760 h use. Eleven out of 762 (1.44%) LED lamps (new at onset of the study) in the 2 houses failed during the 15-month experiment period. The neck area of the LED lamp was hottest, presumably the primary reason for the lamp failure as cracks were noticed in the neck region of all failed LED lamps. No differences were observed in egg weight, hen-day egg production, feed use, and mortality rate between LED and FL regimens. However, hens under the FL had higher eggs per hen housed and better feed conversion than those under the LED during 20 to 70 wk production (P < 0.05). Hens under the LED tended to have less feather uniformity and insulation than those under the FL (P < 0.05). Moreover, hens under the LED showed a larger median avoidance distance than those under the FL at 36 wk age (P < 0.05), indicating that hens under the LED were more alert; but no difference at 60 wk age. More comparative research to quantify behavioral and production responses of different breeds of hens to LED vs. FL lighting seems warranted.

  6. High intensity portable fluorescent light

    NASA Technical Reports Server (NTRS)

    Kendall, F. B.

    1972-01-01

    Eight high intensity portable fluorescent lights were produced. Three prototype lights were also produced, two of which were subsequently updated to the physical and operational configuration of the qualification and flight units. Positioning of lamp apertures and reflectors in these lights is such that the light is concentrated and intensified in a specific pattern rather than widely diffused. Indium amalgam control of mercury vapor pressure in the lamp gives high output at lamp ambient temperatures up to 105 C. A small amount of amalgam applied to each electrode stem helps to obtain fast warm-up. Shrinking a Teflon sleeve on the tube and potting metal caps on each end of the lamp minimizes dispersion of mercury vapor and glass particles in the event of accidental lamp breakage. Operation at 20 kHz allows the lamps to consume more power than at low frequency, thus increasing their light output and raising their efficiency. When used to expose color photographic film, light from the lamps produces results approximately equal to sunlight.

  7. Light Sheet Fluorescence Microscopy (LSFM)

    PubMed Central

    Adams, Michael W.; Loftus, Andrew F.; Dunn, Sarah E.; Joens, Matthew S.; Fitzpatrick, James A.J.

    2015-01-01

    The development of confocal microscopy techniques introduced the ability to optically section fluorescent samples in the axial dimension, perpendicular to the image plane. These approaches, via the placement of a pinhole in the conjugate image plane, provided superior resolution in the axial (z) dimension resulting in nearly isotropic optical sections. However, increased axial resolution, via pinhole optics, comes at the cost of both speed and excitation efficiency. Light Sheet Fluorescent Microscopy (LSFM), a century old idea (Siedentopf and Zsigmondy, 1902) made possible with modern developments in both excitation and detection optics, provides sub-cellular resolution and optical sectioning capabilities without compromising speed or excitation efficiency. Over the past decade, several variations of LSFM have been implemented each with its own benefits and deficiencies. Here we discuss LSFM fundamentals and outline the basic principles of several major light sheet based imaging modalities (SPIM, inverted SPIM, multi-view SPIM, Bessel beam SPIM, and stimulated emission depletion SPIM while considering their biological relevance in terms of intrusiveness, temporal resolution, and sample requirements. PMID:25559221

  8. Sustainable LED Fluorescent Light Replacement Technology

    SciTech Connect

    None, None

    2011-09-30

    Ilumisys and the National Center for Manufacturing Sciences (NCMS) partnered on a three-year project awarded by the United States (U.S.) Department of Energy (DOE), to quantify the impacts of LED lamps, incandescent lamps and fluorescent benchmark lamps over a product lifecycle – i.e. to develop a sustainable design and manufacturing strategy that addresses product manufacturing, use, recycling and disposal scenarios for LED-based lighting. Based on the knowledge gained from extensive product tear-down studies of fluorescent and screw-in lighting products, lifecycle assessment tools, and accelerated lifecycle testing protocols, an interactive Sustainable LED Design Guide has been developed to aid architectural and lighting designers and engineers in making design decisions that consider three important environmental impacts (greenhouse gas emissions, energy use and mercury emission) across all phases of the life of an LED lighting product. Critical information developed for the lifecycle analysis and product feature comparisons is the useful life of the lighting product as well as its performance. The Design Guide is available at www.ncms.org, and was developed based on operational and durability testing of a variety of lighting products including power consumption, light output, and useful life of a lamp in order to allow a more realistic comparison of lamp designs. This report describes the main project tasks, results and innovative features of the lifecycle assessment (LCA)-based design tools, and the key considerations driving the sustainable design of LED lighting systems. The Design Guide incorporates the following three novel features for efficiently evaluating LED lighting features in value-chains: Bill-of-Materials (BOM) Builder – Designers may import process data for each component and supply functional data for the product, including power, consumption, lumen output and expected useful life: Environmental Impact Review – Designs are comparable

  9. D-light for laparoscopic fluorescence diagnosis

    NASA Astrophysics Data System (ADS)

    Gahlen, Johannes; Laubach, Hans-Heinrich; Stern, Josef; Pressmar, Jochen; Pietschmann, Mathias; Herfarth, Christian

    1999-07-01

    To evaluate the role of ALA induced fluorescence diagnosis in laparoscopic surgery, we induced peritoneal carcinosis in rats by multilocular intraabdominal tumorcell implantation (CC531). The animals were photosensitized by intraabdominal ALA lavage. Laparoscopy was performed with both, conventional white and then blue light (D-Light, KARL STORZ Germany) excitation. Laparoscopy with conventional white light showed peritoneal carcinoma foci from 0.1 to 2 cm in diameter. All macroscopically visible tumors (n equals 142) were fluorescence positive after laparoscopic blue light excitation. In addition, 30 laparoscopic not visible (white light) tumors showed fluorescence and were histologically confirmed as colon carcinoma metastases. We conclude that only ALA induced laparoscopic fluorescence detection after blue light excitation is the adequate method to detect the entire extent of the intraabdominal tumor spread. Fluorescence laparoscopy is essential for laparoscopic staging of colorectal cancer because of a higher rate of cancer foci detection.

  10. Compact Fluorescent Light Bulbs (CFLs)

    EPA Pesticide Factsheets

    CFLs can help you save money, use less energy, reduce light bulb changes, and lower greenhouse gas emissions, which lead to climate change. Learn about proper cleanup, recycling and disposal, labels, mercury, and UV radiation.

  11. Light metal production

    DOEpatents

    Fan, Qinbai

    2016-04-19

    An electrochemical process for the production of light metals, particularly aluminum. Such a process involves contacting a light metal source material with an inorganic acid to form a solution containing the light metal ions in high concentration. The solution is fed to an electrochemical reactor assembly having an anode side containing an anode and a cathode side containing a cathode, with anode side and the cathode side separated by a bipolar membrane, with the solution being fed to the anode side. Light metal ions are electrochemically transferred through the bipolar membrane to the cathode side. The process further involves reducing the light metal ions to light metal powder. An associated processing system is also provided.

  12. Fluorescent lighting with aluminum nitride phosphors

    DOEpatents

    Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Srivastava, Alok M.

    2016-05-10

    A fluorescent lamp includes a glass envelope; at least two electrodes connected to the glass envelope; mercury vapor and an inert gas within the glass envelope; and a phosphor within the glass envelope, wherein the phosphor blend includes aluminum nitride. The phosphor may be a wurtzite (hexagonal) crystalline structure Al.sub.(1-x)M.sub.xN phosphor, where M may be drawn from beryllium, magnesium, calcium, strontium, barium, zinc, scandium, yttrium, lanthanum, cerium, praseodymium, europium, gadolinium, terbium, ytterbium, bismuth, manganese, silicon, germanium, tin, boron, or gallium is synthesized to include dopants to control its luminescence under ultraviolet excitation. The disclosed Al.sub.(1-x)M.sub.xN:Mn phosphor provides bright orange-red emission, comparable in efficiency and spectrum to that of the standard orange-red phosphor used in fluorescent lighting, Y.sub.2O.sub.3:Eu. Furthermore, it offers excellent lumen maintenance in a fluorescent lamp, and does not utilize "critical rare earths," minimizing sensitivity to fluctuating market prices for the rare earth elements.

  13. Light-induced fluorescence for pulpal diagnosis

    NASA Astrophysics Data System (ADS)

    Ebihara, Arata; Liaw, Lih-Huei L.; Krasieva, Tatiana B.; Wilder-Smith, Petra B. B.

    2001-04-01

    A direct non-histological means of pulpal diagnosis remains elusive to clinical practice. Clinical vitality testing remains limited to electric, thermal criteria, or laser Doppler flowmetry. The goal of these investigations was to determine the feasibility of using light-induced fluorescence as a non-invasive modality for pulpal evaluation. Such a capability would, for example, permit expanded use of pulpotomy/pulpectomy techniques. Clinically healthy and diseased human extirpated pulpal tissues were used in this study. After excision, they were rapidly frozen and standard cryosections prepared. Measurement of tissue excitation/emission characteristics was performed using spectrographic analysis. A low-light level fluorescence microscopy system was then used to image autofluorescence localization and intensity at optimal excitation/detection parameters. Excitation/detection parameters used in this study included 405/605, 405/635, 405/670, 440/550, and 440/635. Autofluorescence intensities in healthy tissues were significantly stronger than those in diseased tissues at optimal parameters. It is postulated that autofluorescence characteristics are related to pathology- related structural changes in the pulp. This work provides the basis for further investigation into the relation between autofluorescence, histology and clinical symptoms.

  14. Comparison of milk oxidation by exposure to LED and fluorescent light.

    PubMed

    Brothersen, C; McMahon, D J; Legako, J; Martini, S

    2016-04-01

    Light-induced oxidation of milk has been well studied. Exposure of milk to UV light facilitates the oxidation of fats to aldehydes, and the degradation of sulfur-containing amino acids, both of which contribute to off-flavors. In addition, vitamin A and riboflavin are easily degraded by UV light. These reactions occur rapidly and are exacerbated by bright fluorescent lights in retail dairy cases. The invention of white light-emitting diodes (LED) may provide a solution to this oxidation problem. In this study, fresh milk containing 1% fat and fortified with vitamin A and riboflavin was exposed to LED at 4,000 lx, or fluorescent light at 2,200 lx for 24 h. Milk samples exposed to LED or fluorescent light, as well as milk protected from light, were analyzed by a consumer acceptance panel, and a trained flavor panel. In addition, vitamin A, riboflavin, and the production of volatile compounds were quantified. Exposure to light resulted in a reduction of cooked/sweet, milkfat, and sweet flavors and increased the intensity of butterscotch, cardboard, and astringency. In general, exposure to fluorescent light resulted in greater changes in the milk than exposure to LED even though the LED was at higher intensity. Consumers were able detect off-flavors in milk exposed to fluorescent light after 12 h and LED after 24 h of exposure. The riboflavin and vitamin A content was reduced by exposure to fluorescent light, whereas there was no significant reduction caused by LED compared with the non-light-exposed control. Production of hexanal, heptanal, 2-heptanal, octanal, 2-octanal nonanal, dimethyl sulfide, and caproic acid vinyl ester from the light-induced degradation of fats was significantly higher with fluorescent than LED. Production of these compounds was significantly higher with both light treatments than in the control milk. This study indicates that LED is less destructive to milk than fluorescent light.

  15. High Hats, Swiss Cheese, and Fluorescent Lighting?

    SciTech Connect

    McCullough, Jeffrey J.; Gordon, Kelly L.

    2002-08-30

    For DOE, PNNL is conducting a competitive procurement to promote market introduction of new residential recessed downlights (also known as ''recessed cans'' or ''high hats'') that are airtight, rated for insulated ceilings, and hard-wired for CFLs. This paper discusses the potential energy savings of new high-efficiency downlights, and the results of product testing to date. Recessed downlights are the most popular residential lighting fixtures in the United States, with 21.7 million fixtures sold in 2000. An estimated 350 million are currently installed in American homes. Recessed cans are relatively inexpensive, and provide an unobtrusive, directed source of light for kitchens, hallways, and living rooms. Recessed cans are energy-intensive in three ways. First, virtually all recessed cans currently installed in the residential sector use incandescent light sources, typically reflector-type lamps drawing 65-150 watts. Second, heat from incandescent lamps adds to air-conditioning loads. Third, most installed recessed cans are not airtight, so they allow conditioned air to escape from the living area into unconditioned spaces such as attics. Addressing both lighting energy use and air leakage in recessed cans has proven challenging. Lighting energy efficiency is greatly improved by using CFLs. Air leakage can be addressed by making fixtures airtight. But when CFLs are used in an airtight recessed can, heat generated by the lamp and ballast is trapped within the fixture. Excessive heat causes reduced light output and shorter lifespan of the CFL. The procurement was designed to overcome these technical challenges and make new products available in the marketplace.

  16. Light cone matrix product

    SciTech Connect

    Hastings, Matthew B

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  17. 16 CFR 305.15 - Labeling for lighting products.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Labeling for lighting products. 305.15...) Required Disclosures § 305.15 Labeling for lighting products. (a) Fluorescent lamp ballasts and luminaires... the specifications and minimum sizes displayed in Prototype Label 5 in appendix L. (3) Lighting...

  18. 16 CFR 305.15 - Labeling for lighting products.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Labeling for lighting products. 305.15...) Required Disclosures § 305.15 Labeling for lighting products. (a) Fluorescent lamp ballasts and luminaires... the specifications and minimum sizes displayed in Prototype Label 5 in appendix L. (3) Lighting...

  19. Detail of window treatment, suspended radiators, and fluorescent lights, prop ...

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

    Detail of window treatment, suspended radiators, and fluorescent lights, prop shop. View to east. - San Bernardino Valley College, Auditorium, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  20. Light emission from compound eye with conformal fluorescent coating

    NASA Astrophysics Data System (ADS)

    Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

    2015-03-01

    Compound eyes of insects are attractive biological systems for engineered biomimicry as artificial sources of light, given their characteristic wide angular field of view. A blowfly eye was coated with a thin conformal fluorescent film, with the aim of achieving wide field-of-view emission. Experimental results showed that the coated eye emitted visible light and that the intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  1. Organimetallic Fluorescent Complex Polymers For Light Emitting Applications

    DOEpatents

    Shi, Song Q.; So, Franky

    1997-10-28

    A fluorescent complex polymer with fluorescent organometallic complexes connected by organic chain spacers is utilized in the fabrication of light emitting devices on a substantially transparent planar substrate by depositing a first conductive layer having p-type conductivity on the planar surface of the substrate, depositing a layer of a hole transporting and electron blocking material on the first conductive layer, depositing a layer of the fluorescent complex polymer on the layer of hole transporting and electron blocking material as an electron transporting emissive layer and depositing a second conductive layer having n-type conductivity on the layer of fluorescent complex polymer.

  2. 16 CFR 305.15 - Labeling for lighting products.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Labeling for lighting products. 305.15 Section 305.15 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC ACTS OF CONGRESS...) Required Disclosures § 305.15 Labeling for lighting products. (a) Fluorescent lamp ballasts and...

  3. New method of acne disease fluorescent diagnostics in natural and fluorescent light and treatment control

    NASA Astrophysics Data System (ADS)

    Karimova, L. N.; Berezin, A. N.; Shevchik, S. A.; Kharnas, S. S.; Kusmin, S. G.; Loschenov, V. B.

    2005-08-01

    In the given research the new method of fluorescent diagnostics (FD) and photodynamic therapy (PDT) control of acne disease is submitted. Method is based on simultaneous diagnostics in natural and fluorescent light. PDT was based on using 5-ALA (5- aminolevulinic acid) preparation and 600-730 nanometers radiation. If the examined site of a skin possessed a high endogenous porphyrin fluorescence level, PDT was carried out without 5-ALA. For FD and treatment control a dot spectroscopy and the fluorescent imaging of the affected skin were used.

  4. RNA fluorescence with light-up aptamers

    NASA Astrophysics Data System (ADS)

    Ouellet, Jonathan

    2016-06-01

    Seeing is not only believing; it also includes understanding. Cellular imaging with GFP in live cells has been transformative in many research fields. Modulation of cellular regulation is tightly regulated and innovative imaging technologies contribute to further understand cellular signaling and physiology. New types of genetically encoded biosensors have been developed over the last decade. They are RNA aptamers that bind with their cognate fluorogen ligands and activate their fluorescence. The emergence and the evolution of these RNA aptamers as well as their conversion into a wide spectrum of applications are examined in a global way.

  5. Benefits and Costs of Ultraviolet Fluorescent Lighting

    PubMed Central

    Lestina, Diane C.; Miller, Ted R.; Knoblauch, Richard; Nitzburg, Marcia

    1999-01-01

    Objective To demonstrate the improvements in detection and recognition distances using fluorescent roadway delineation and auxiliary ultra-violet (UVA) headlights and determine the reduction in crashes needed to recover increased costs of the UVA/flourescent technology. Methods Field study comparisons with and without UVA headlights. Crash types potentially reduced by UVA/flourescent technology were estimated using annual crash and injury incidence data from the General Estimates System (1995–1996) and the 1996 Fatality Analysis Reporting System. Crash costs were computed based on body region and threat-to-life injury severity. Results Significant improvements in detection and recognition distances for pedestrian scenarios, ranging from 34% to 117%. A 19% reduction in nighttime motor vehicle crashes involving pedestrians or pedal-cycles will pay for the additional UVA headlight costs. Alternatively, a 5.5% reduction in all relevant nighttime crashes will pay for the additional costs of UVA headlights and fluorescent highway paint combined. Conclusions If the increased detection and recognition distances resulting from using UVA/flourescent technology as shown in this field study reduce relevant crashes by even small percentages, the benefit cost ratios will still be greater than 2; thus, the UVA/flourescent technology is very cost-effective and a definite priority for crash reductions.

  6. Acrodynia: exposure to mercury from fluorescent light bulbs

    SciTech Connect

    Tunnessen, W.W. Jr.; McMahon, K.J.; Baser, M.

    1987-05-01

    Medical attention was sought for a 23-month-old toddler because of anorexia, weight loss, irritability, profuse sweating, peeling and redness of his fingers and toes, and a miliarial rash. The diagnosis was mercury poisoning, and an investigation of his environment disclosed that he had been exposed to mercury from broken fluorescent light bulbs. Acrodynia resulting from fluorescent bulbs has not been previously reported.

  7. Integrated ultrasonic particle positioning and low excitation light fluorescence imaging

    SciTech Connect

    Bernassau, A. L.; Al-Rawhani, M.; Beeley, J.; Cumming, D. R. S.

    2013-12-09

    A compact hybrid system has been developed to position and detect fluorescent micro-particles by combining a Single Photon Avalanche Diode (SPAD) imager with an acoustic manipulator. The detector comprises a SPAD array, light-emitting diode (LED), lenses, and optical filters. The acoustic device is formed of multiple transducers surrounding an octagonal cavity. By stimulating pairs of transducers simultaneously, an acoustic landscape is created causing fluorescent micro-particles to agglomerate into lines. The fluorescent pattern is excited by a low power LED and detected by the SPAD imager. Our technique combines particle manipulation and visualization in a compact, low power, portable setup.

  8. Light cluster production at NICA

    NASA Astrophysics Data System (ADS)

    Bastian, N.-U.; Batyuk, P.; Blaschke, D.; Danielewicz, P.; Ivanov, Yu. B.; Karpenko, Iu.; Röpke, G.; Rogachevsky, O.; Wolter, H. H.

    2016-08-01

    Light cluster production at the NICA accelerator complex offers unique possibilities to use these states as "rare probes" of in-medium characteristics such as phase space occupation and early flow. In order to explain this statement, in this contribution theoretical considerations from the nuclear statistical equilibrium model and from a quantum statistical model of cluster production are supplemented with a discussion of a transport model for light cluster formation and with results from hydrodynamic simulations combined with the coalescence model.

  9. Photocatalytic oxidation of volatile organic compounds using fluorescent visible light.

    PubMed

    Chapuis, Yannick; Klvana, Danilo; Guy, Christophe; Kirchnerova, Jitka

    2002-07-01

    Photocatalytic oxidation (PCO) of volatile organic compounds (VOCs) is a highly attractive alternative technology for purification and deodorization of indoor air. The main objectives of this study were to demonstrate that a common fluorescent visible light (FVL) lamp can be used to effectively remove by PCO low concentrations of VOCs from slightly contaminated air and to provide some fundamental and technical details on the process. The target VOC was n-butanol, which is a standard reference odorant. Its PCO was studied under a long residence time in a 3.7-L cylindrical reactor with commercial titanium dioxide (TiO2) as the reference photocatalyst and using mostly FVL for illumination. For comparison only, a UV (black) light lamp was used. The gas-phase products were detected and quantified online by gas chromatography (GC). The effects of reactor residence time, of inlet concentration, and of the relative light intensity on the efficiency of the process were also evaluated. At a high n-butanol concentration (0.1 vol %), butanal and propanal were identified as the intermediate products of the process; ethanal appeared when the initial concentration was < or = 850 ppm(v). This indicates that PCO leading to CO2 and H2O is relatively slow and proceeds in a stepwise manner. Although the efficiency of the process with an FVL lamp was significantly lower than when using a UV black light, complete PCO of low concentrations was achieved for 100 ppm(v). In a search for a material with photoactivation extended to higher wavelengths or increased photoactivity, several samples of transition metal- or silver ion-doped (2 atomic %) TiO2 as well as SrTi(1-x-)Fe(x)O3 (x = 0.1 and 0.15) perovskites were included in the study. None of these materials was more active than pure TiO2. The results of this study open new horizons in the area of in door air quality (IAQ) control.

  10. Blue-green phosphor for fluorescent lighting applications

    DOEpatents

    Srivastava, Alok; Comanzo, Holly; Manivannan, Venkatesan; Setlur, Anant Achyut

    2005-03-15

    A fluorescent lamp including a phosphor layer including Sr.sub.4 Al.sub.14 O.sub.25 :Eu.sup.2+ (SAE) and at least one of each of a red, green and blue emitting phosphor. The phosphor layer can optionally include an additional, deep red phosphor and a yellow emitting phosphor. The resulting lamp will exhibit a white light having a color rendering index of 90 or higher with a correlated color temperature of from 2500 to 10000 Kelvin. The use of SAE in phosphor blends of lamps results in high CRI light sources with increased stability and acceptable lumen maintenance over, the course of the lamp life.

  11. Spectroscopic Analysis of Today's Compact Fluorescent Light Bulbs

    NASA Astrophysics Data System (ADS)

    Pluhar, Edward

    2012-03-01

    In today's consumer market, there are many different light bulbs that claim to produce `natural' light. In my research, I both quantitatively and qualitatively analyzed this claim. First, utilizing a spectroscope, I compared the spectra emitted by different brands and types of compact fluorescent light (CFL) bulbs to the spectra emitted by the Sun. Once the bulbs were quantitatively analyzed, I proceeded to qualitatively analyze them by exposing subjects to the different bulbs. The subjects were asked to rate the quality of color in different pictures illuminated by each type of CFL. From these tests, I was able to determine the ``best'' CFL bulbs, and conclude whether the health risks associated with CFL bulbs outweigh the cost savings, longevity of the bulbs, and/or quality of light benefits.

  12. Affective and cognitive reactions to subliminal flicker from fluorescent lighting.

    PubMed

    Knez, Igor

    2014-05-01

    This study renews the classical concept of subliminal perception (Peirce & Jastrow, 1884) by investigating the impact of subliminal flicker from fluorescent lighting on affect and cognitive performance. It was predicted that low compared to high frequency lighting (latter compared to former emits non-flickering light) would evoke larger changes in affective states and also impair cognitive performance. Subjects reported high rather than low frequency lighting to be more pleasant, which, in turn, enhanced their problem solving performance. This suggests that sensory processing can take place outside of conscious awareness resulting in conscious emotional consequences; indicating a role of affect in subliminal/implicit perception, and that positive affect may facilitate cognitive task performance.

  13. Remediation plan for fluorescent light fixtures containing polychlorinated biphenyls (PCBs)

    SciTech Connect

    1992-04-30

    This report describes the remedial action to achieve compliance with 29 CFR 1910 Occupational Safety and Health Administration (OSHA) requirements of fluorescent light fixtures containing PCBs at K-25 site. This remedial action is called the Remediation Plan for Fluorescent Light Fixtures Containing PCBs at the K-25 Site (The Plan). The Plan specifically discusses (1) conditions of non-compliance, (2) alternative solutions, (3) recommended solution, (4) remediation plan costs, (5) corrective action, (6) disposal of PCB waste, (7) training, and (8) plan conclusions. The results from inspections by Energy Systems personnel in 2 buildings at K-25 site and statistical extension of this data to 91 selected buildings at the K-25 site indicates that there are approximately 28,000 fluorescent light fixtures containing 47,036 ballasts. Approximately 38,531 contain PCBs and 2,799 of the 38,531 ballasts are leaking PCBs. Review of reportable occurrences at K-25 for the 12 month period of September 1990 through August 1991 shows that Energy Systems personnel reported 69 ballasts leaking PCBs. Each leaking ballast is in non-compliance with 29 CFR 1910 - Table Z-1-A. The age of the K-25 facilities indicate a continued and potential increase in ballasts leaking PCBs. This report considers 4 alternative solutions for dealing with the ballasts leaking PCBs. The advantages and disadvantages of each alternative solution are discussed and ranked using cost of remediation, reduction of health risks, and compliance with OSHA as criteria.

  14. Light use efficiency of terrestrial vegetation from remote sensing of chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Badgley, G. M.; Guan, K.; Berry, J. A.; Lobell, D. B.; Ryu, Y.

    2014-12-01

    Light use efficiency, the rate with which plants use absorbed photons to fix carbon dioxide, is a crucial parameter for estimating terrestrial carbon fluxes. Estimates of light use efficiency lie at the heart of how we model and understand ecosystem productivity. Here, we make use of the recent availability of high-resolution, multi-year records of remotely sensed measurements of chlorophyll fluorescence to refine estimates of light use efficiency in terrestrial ecosystems at the global scale. Directly estimating light use efficiency from remote sensing can help guide the current approach of constraining a theoretical maximum light use efficiency using meteorological data. We explore the usefulness of a derived light use efficiency at the global scale from remotely sensed records of chlorophyll fluorescence, photosynthetically active radiation, and canopy leaf area. Our estimates of light use efficiency show good agreement with light use efficiency calculated using Fluxtower data spanning several continents and a wide variety of ecosystems. We further benchmark our approach against the light use efficiency estimated from a variety of ecosystem models, such as BESS. Further refinement of our proposed technique promises to advance our ability to detect ecosystem stresses and further constrain our estimates of carbon fluxes within terrestrial ecosystems.

  15. Infrared imaging of LED lighting tubes and fluorescent tubes

    NASA Astrophysics Data System (ADS)

    Siikanen, Sami; Kivi, Sini; Kauppinen, Timo; Juuti, Mikko

    2011-05-01

    The low energy efficiency of conventional light sources is mainly caused by generation of waste heat. We used infrared (IR) imaging in order to monitor the heating of both LED tube luminaires and ordinary T8 fluorescent tubes. The IR images showed clearly how the surface temperatures of the fluorescent tube ends quickly rose up to about +50...+70°C, whereas the highest surface temperatures seen on the LED tubes were only about +30...+40°C. The IR images demonstrated how the heat produced by the individual LED chips can be efficiently guided to the supporting structure in order to keep the LED emitters cool and hence maintain efficient operation. The consumed electrical power and produced illuminance were also recorded during 24 hour measurements. In order to assess the total luminous efficacy of the luminaires, separate luminous flux measurements were made in a large integrating sphere. The currently available LED tubes showed efficacies of up to 88 lm/W, whereas a standard "cool white" T8 fluorescent tube produced ca. 75 lm/W. Both lamp types gave ca. 110 - 130 lx right below the ceiling-mounted luminaire, but the LED tubes consume only 40 - 55% of the electric power compared to fluorescent tubes.

  16. Pulsed-light imaging for fluorescence guided surgery under normal room lighting.

    PubMed

    Sexton, Kristian; Davis, Scott C; McClatchy, David; Valdes, Pablo A; Kanick, Stephen C; Paulsen, Keith D; Roberts, David W; Pogue, Brian W

    2013-09-01

    Fluorescence guided surgery (FGS) is an emerging technology that has demonstrated improved surgical outcomes. However, dim lighting conditions required by current FGS systems are disruptive to standard surgical workflow. We present a novel FGS system capable of imaging fluorescence under normal room light by using pulsed excitation and gated acquisition. Images from tissue-simulating phantoms confirm visual detection down to 0.25 μM of protoporphyrin IX under 125 μW/cm2 of ambient light, more than an order of magnitude lower than that measured with the Zeiss Pentero in the dark. Resection of orthotopic brain tumors in mice also suggests that the pulsed-light system provides superior sensitivity in vivo.

  17. Photodynamic tumor therapy and on-line fluorescence spectroscopy after ALA administration using 633-nm light as therapeutic and fluorescence excitation radiation

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Kienle, Alwin; Boehncke, Wolf-Henning; Kaufmann, Roland; Rueck, Angelika C.; Meier, Thomas H.; Steiner, Rudolf W.

    1994-09-01

    Photodynamic therapy (PDT) and on-line fluorescence spectroscopy were carried out on human tumors after 5-aminolevulinic acid (ALA) administration using 633-nm light of a dye laser as therapeutic radiation and as fluorescence excitation radiation. This has the advantages of (1) enabling use of one laser for PDT and fluorescence diagnosis only, (2) enabling the possibility of on-line fluorescence measurements, and (3) exciting protoporphyrin molecules in deep tissue layers. Monte Carlo calculations were carried out to determine excitation and fluorescence phonon distribution in case of red and violet excitation radiation. The results show the possibility of depth-resolved measurements on the fluorophore distribution by variation of excitation wavelength. The high penetration depth of 633-nm radiation results in a higher ratio of the 700-nm protoporphyrin fluorescence of the xenotransplanted tumor It to Is compared with 407-nm excitation. No values greater than 1 for the ratio I/Is were found, however, in case of intravenous ALA injection even for red excitation. Therefore, a large amount of ALA will be metabolized in the skin and can cause photosensitivity of the patient when applied systematically. In contrast, protoporphyrin fluorescence limited to the pretreated skin area was detected in case of topically applied ALA to patients with mycosis funcoides and erythroplasy of Queyrat. The influence of remitted excitation light and of the spontaneous radiation from the laser as well as the possible excitation of foodbased degradation products of chlorophyll has to be considered in high-sensitivity fluorescence measurements.

  18. Photolysis of Indole-Containing Mycotoxins to Fluorescent Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Photochemical reaction of the non-fluorescent mycotoxin cyclopiazonic acid (CPA) to fluorescent products was recently reported. Because CPA contains an indole moiety, believed to contribute to the fluorescence, it was of interest to determine whether the effect might be more generally applicable to ...

  19. Simulating the illuminance and the efficiency of the LED and fluorescent lights used in indoor lighting design.

    PubMed

    Tsuei, Chih-Hsuan; Pen, Jui-Wen; Sun, Wen-Shing

    2008-11-10

    In this study we simulate the illuminance and efficiency of four different types of reflector LED and fluorescent light sources for interior illumination. According to our calculation results of the examination of simulations and real situations, we find that the LEDs do perform better than fluorescent lights. We also consider the problems of glare with LED lights by utilizing a diffuser to protect the eyes. We are assured of the potential advantages of LED lighting in the future.

  20. The effect of modern compact fluorescent lights on voltage distortion

    SciTech Connect

    Pileggi, D.J.; Gulachenski, E.M.; Root, C.E. ); Gentile, T.J. ); Emanuel, A.E. )

    1993-07-01

    This paper presents the results of a computer simulation of three real life 13.8kV feeders supplying consumers with non-linear loads which include CFL (Compact Fluorescent Lights) with electronic ballasts. The computer simulations are supported by laboratory testing and in-the-home installation/monitoring of CFL. The results of the laboratory tests and in-the-home monitoring were combined with load research information regarding residential load profiles to produce load models for use in computer simulation of the behavior of the three distribution feeders. The input current to electronically ballasted CFL has unusually high distortion, THD (total harmonic distortion) > 100%. The man conclusion of this work is that for a 15kV class feeder with a maximum 10 MVA load, the total load of electronically ballasted CFL should not exceed 100kW is the voltage THD is to be kept [<=] 5%.

  1. Using Light Sheet Fluorescence Microscopy to Image Zebrafish Eye Development

    PubMed Central

    Sidhaye, Jaydeep; Tomancak, Pavel; Preibisch, Stephan; Norden, Caren

    2016-01-01

    Light sheet fluorescence microscopy (LSFM) is gaining more and more popularity as a method to image embryonic development. The main advantages of LSFM compared to confocal systems are its low phototoxicity, gentle mounting strategies, fast acquisition with high signal to noise ratio and the possibility of imaging samples from various angles (views) for long periods of time. Imaging from multiple views unleashes the full potential of LSFM, but at the same time it can create terabyte-sized datasets. Processing such datasets is the biggest challenge of using LSFM. In this protocol we outline some solutions to this problem. Until recently, LSFM was mostly performed in laboratories that had the expertise to build and operate their own light sheet microscopes. However, in the last three years several commercial implementations of LSFM became available, which are multipurpose and easy to use for any developmental biologist. This article is primarily directed to those researchers, who are not LSFM technology developers, but want to employ LSFM as a tool to answer specific developmental biology questions. Here, we use imaging of zebrafish eye development as an example to introduce the reader to LSFM technology and we demonstrate applications of LSFM across multiple spatial and temporal scales. This article describes a complete experimental protocol starting with the mounting of zebrafish embryos for LSFM. We then outline the options for imaging using the commercially available light sheet microscope. Importantly, we also explain a pipeline for subsequent registration and fusion of multiview datasets using an open source solution implemented as a Fiji plugin. While this protocol focuses on imaging the developing zebrafish eye and processing data from a particular imaging setup, most of the insights and troubleshooting suggestions presented here are of general use and the protocol can be adapted to a variety of light sheet microscopy experiments. PMID:27167079

  2. Discrimination of Dendrobium officinale and its common adulterants by combination of normal light and fluorescence microscopy.

    PubMed

    Chu, Chu; Yin, Huimin; Xia, Li; Cheng, Dongping; Yan, Jizhong; Zhu, Lin

    2014-03-24

    The stems of Dendrobium officinale Kimura et Migo, named Tie-pi-shi-hu, is one of the most endangered and precious species in China. Because of its various pharmacodynamic effects, D. officinale is widely recognized as a high-quality health food in China and other countries in south and south-east Asia. With the rising interest of D. officinale, its products have a high price due to a limited supply. This high price has led to the proliferation of adulterants in the market. To ensure the safe use of D. officinale, a fast and convenient method combining normal and fluorescence microscopy was applied in the present study to distinguish D. officinale from three commonly used adulterants including Zi-pi-shi-hu (D. devonianum), Shui-cao-shi-hu (D. aphyllum), Guang-jie-shi-hu (D. gratiosissimum). The result demonstrated that D. officinale could be identified by the characteristic "two hat-shaped" vascular bundle sheath observed under the fluorescence microscopy and the distribution of raphides under normal light microscopy. The other three adulterants could be discriminated by the vascular bundle differences and the distribution of raphides under normal light microscopy. This work indicated that combination of normal light and fluorescence microscopy is a fast and efficient technique to scientifically distinguish D. officinale from the commonly confused species.

  3. A light diet for a giant appetite: An assessment of China's proposed fluorescent lamp standard

    SciTech Connect

    Lin, Jiang

    2002-04-11

    Lighting has been one of the fastest growing electric end-uses in China over the last twenty years, with an average annual growth rate of 14%. Fluorescent lighting provides a significant portion of China's lighting need. In 1998, China produced 680 million fluorescent lamps, of which 420 million were linear fluorescent lamps of various diameters (T8 to T12). There are substantial variations both in energy efficiency and lighting performance among locally produced fluorescent lamps. Such variations present a perfect opportunity for policy intervention through efficiency standards to promote the adoption of more efficient fluorescent lamps in China. This paper analyzes China's proposed minimum efficiency standard for fluorescent lamps and presents an assessment of its likely impacts on China's lighting energy consumption and GHG emissions.

  4. Neutral red as a specific light-up fluorescent probe for i-motif DNA.

    PubMed

    Xu, Lijun; Wang, Jine; Sun, Na; Liu, Min; Cao, Yi; Wang, Zhili; Pei, Renjun

    2016-12-06

    We report a specific light-up fluorescent probe for i-motif DNA for the first time. Compared with the previously reported probes, neutral red could selectively interact with an i-motif and show a significant increase in its fluorescence. This feature makes it advantageous for designing label-free fluorescent sensing systems.

  5. "Light" Tobacco Products Pose Heavy Health Risks

    MedlinePlus

    ... Products For Consumers Home For Consumers Consumer Updates "Light" Tobacco Products Pose Heavy Health Risks Share Tweet ... Feed A federal law is restricting the words “light,” “low,” and “mild” from tobacco products now on ...

  6. Physically-based in silico light sheet microscopy for visualizing fluorescent brain models

    PubMed Central

    2015-01-01

    Background We present a physically-based computational model of the light sheet fluorescence microscope (LSFM). Based on Monte Carlo ray tracing and geometric optics, our method simulates the operational aspects and image formation process of the LSFM. This simulated, in silico LSFM creates synthetic images of digital fluorescent specimens that can resemble those generated by a real LSFM, as opposed to established visualization methods producing visually-plausible images. We also propose an accurate fluorescence rendering model which takes into account the intrinsic characteristics of fluorescent dyes to simulate the light interaction with fluorescent biological specimen. Results We demonstrate first results of our visualization pipeline to a simplified brain tissue model reconstructed from the somatosensory cortex of a young rat. The modeling aspects of the LSFM units are qualitatively analysed, and the results of the fluorescence model were quantitatively validated against the fluorescence brightness equation and characteristic emission spectra of different fluorescent dyes. AMS subject classification Modelling and simulation PMID:26329404

  7. Characteristics of Fluorescence and Delayed Light Emission from Green Photosynthetic Bacteria and Algae

    PubMed Central

    Clayton, Roderick K.

    1965-01-01

    Green photosynthetic bacteria exhibit variations in the intensity of their fluorescence during illumination. The initial intensity of fluorescence, measured at the onset of illumination, has a spectrum in which the major pigment Chlorobium chlorophyll predominates. The minor pigment bacteriochlorophyll predominates in the spectrum of the time-varying part of the fluorescence. The spectrum of delayed light emission is identical to that of the time-varying fluorescence. The variations in fluorescence also resemble the delayed light in their kinetics and in their dependence on exciting light intensity. Similar results are obtained for the kinetics of prompt and delayed light emission in the algae Chlorella and Anacystis. These findings raise the possibility that the variations in fluorescence actually represent a fast component of delayed light emission, of intensity comparable to the intensity of fluorescence. In Anacystis there is an outburst of light emission that develops after the exciting light has been turned off, reaching a maximum intensity after 1 to 3 seconds. This emitted light has the spectrum of chlorophyll fluorescence. It appears to be a novel example of bioluminescence with singlet excited chlorophyll as the emitter. PMID:14324979

  8. Obstacles and opportunities in the commercialization of the solid-state-electronic fluorescent-lighting ballast

    SciTech Connect

    Johnson, D.R.; Marcus, A.A.; Campbell, R.S.; Sommers, P.; Skumatz, L.; Berk, B.; Petty, P.; Eschbach, C.

    1981-10-01

    The Solid State Ballast (SSB) Program, aimed at improving the efficiency of fluorescent lights, is described. The first generation of solid state electronic ballasts has been developed and the technology has been transferred to the private sector. This report examines the opportunities for rapid dissemination of this technology into the marketplace. It includes a description of product characteristics and their influence on the commercialization of the SSB, a description of the technology delivery system presently used by the ballast industry, an analysis of the market for SSB, and identification of some high-leverage opportunities to accelerate the commercialization process. (MCW)

  9. Obstacles and opportunities in the commercialization of the solid state electronic fluorescent lighting ballast

    NASA Astrophysics Data System (ADS)

    Johnson, D. R.; Marcus, A. A.; Campbell, R. S.; Sommers, P.; Skumatz, L.; Berk, B.; Petty, P.; Eschbach, C.

    1981-10-01

    A solid state ballast (SSB), which improves the efficiency of fluorescent lights, is described. The first generation of solid state electronic ballasts was developed and the technology was transferred to the private sector. The opportunities for rapid dissemination of this technology into the marketplace is examined. Product characteristics and their influence on the commercialization of the SSB, a description of the technology delivery system presently used by the ballast industry, an analysis of the market for SSB, and identification of some high leverage opportunities to accelerate the commercialization process are included.

  10. Heat generation and light scattering of green fluorescent protein-like pigments in coral tissue

    NASA Astrophysics Data System (ADS)

    Lyndby, Niclas H.; Kühl, Michael; Wangpraseurt, Daniel

    2016-05-01

    Green fluorescent protein (GFP)-like pigments have been proposed to have beneficial effects on coral photobiology. Here, we investigated the relationships between green fluorescence, coral heating and tissue optics for the massive coral Dipsastraea sp. (previously Favia sp.). We used microsensors to measure tissue scalar irradiance and temperature along with hyperspectral imaging and combined imaging of variable chlorophyll fluorescence and green fluorescence. Green fluorescence correlated positively with coral heating and scalar irradiance enhancement at the tissue surface. Coral tissue heating saturated for maximal levels of green fluorescence. The action spectrum of coral surface heating revealed that heating was highest under red (peaking at 680 nm) irradiance. Scalar irradiance enhancement in coral tissue was highest when illuminated with blue light, but up to 62% (for the case of highest green fluorescence) of this photon enhancement was due to green fluorescence emission. We suggest that GFP-like pigments scatter the incident radiation, which enhances light absorption and heating of the coral. However, heating saturates, because intense light scattering reduces the vertical penetration depth through the tissue eventually leading to reduced light absorption at high fluorescent pigment density. We conclude that fluorescent pigments can have a central role in modulating coral light absorption and heating.

  11. Heat generation and light scattering of green fluorescent protein-like pigments in coral tissue

    PubMed Central

    Lyndby, Niclas H.; Kühl, Michael; Wangpraseurt, Daniel

    2016-01-01

    Green fluorescent protein (GFP)-like pigments have been proposed to have beneficial effects on coral photobiology. Here, we investigated the relationships between green fluorescence, coral heating and tissue optics for the massive coral Dipsastraea sp. (previously Favia sp.). We used microsensors to measure tissue scalar irradiance and temperature along with hyperspectral imaging and combined imaging of variable chlorophyll fluorescence and green fluorescence. Green fluorescence correlated positively with coral heating and scalar irradiance enhancement at the tissue surface. Coral tissue heating saturated for maximal levels of green fluorescence. The action spectrum of coral surface heating revealed that heating was highest under red (peaking at 680 nm) irradiance. Scalar irradiance enhancement in coral tissue was highest when illuminated with blue light, but up to 62% (for the case of highest green fluorescence) of this photon enhancement was due to green fluorescence emission. We suggest that GFP-like pigments scatter the incident radiation, which enhances light absorption and heating of the coral. However, heating saturates, because intense light scattering reduces the vertical penetration depth through the tissue eventually leading to reduced light absorption at high fluorescent pigment density. We conclude that fluorescent pigments can have a central role in modulating coral light absorption and heating. PMID:27225857

  12. 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

    2017-03-02

    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 (∼710 nm) 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 710 nm 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.

  13. 78 FR 14357 - Certain Compact Fluorescent Reflector Lamps, Products Containing Same and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... COMMISSION Certain Compact Fluorescent Reflector Lamps, Products Containing Same and Components Thereof... importation of certain compact fluorescent reflector lamps, products containing same and components thereof by... importation of certain compact fluorescent reflector lamps, products containing same and components thereof...

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

    NASA Technical Reports Server (NTRS)

    Mickens, Matthew A.

    2012-01-01

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

  15. Ultraviolet light output of compact fluorescent lamps: comparison to conventional incandescent and halogen residential lighting sources.

    PubMed

    Nuzum-Keim, A D; Sontheimer, R D

    2009-05-01

    Patients with photosensitive dermatologic and systemic diseases often question the ultraviolet light (UVL) output of household lighting sources. Such individuals have increasing concern about potential UVL exposure from energy-efficient compact fluorescent lamps (CFL), as little data have been presented concerning their UVL output. The objective was to compare, via pilot study, the levels of ultraviolet A (UVA) and ultraviolet B (UVB) leak between residential lighting sources. Equivalent wattage CFL, incandescent and halogen bulbs were purchased from local retailers in Oklahoma City, Oklahoma, USA. The UVA and UVB outputs of these sources were measured under controlled conditions at 10, 25, 50, 100 and 150 cm away from the light source using an IL-1700 research radiometer equipped with UVA and UVB detectors. Negligible UVB and UVA was detected at 100 and 150 cm. Therefore, data were analysed from measurements at 10, 25 and 50 cm only. The results demonstrated UVA leak highest from incandescent and halogen bulbs, and UVB leak highest from CFL. The overall UVA/UVB leak was lowest from CFL shielded during the manufacturing process. In conclusion, patients with photosensitivity have choices depending on their relative risk from different UVL wavelength spectra. UVB exposure risk may be reduced the greatest by utilising CFL with manufacturer-provided shields.

  16. Fluorescent property of indocyanine green (ICG) rubber ring using LED and laser light sources

    PubMed Central

    Hong, Nha Young; Kim, Hong Rae; Lee, Hyun Min; Sohn, Dae Kyung; Kim, Kwang Gi

    2016-01-01

    Fluorescent properties of ICG depends on solvent. Fluorescent characteristics of ICG rubber rings and optimized detection system condition were identified. The fluorescent rubber rings are produced by drying mixture of ICG solution and liquid rubber. LED and laser light sources were used to test differences between them. Other variables are ICG molar concentration (100, 80, 60, 40, 20, 10μM), excitation light spectrum (740, 760, 785nm) and angle of view (0~80°). We observed that ICG ring emitted fluorescence at longer wavelength than in blood and aqueous state. Observation angle between 0 and 50 provided similar brightness of images, while others are significantly less luminous. Excitation light between 740~760nm ensured non-overlapping spectrums of excitation light and fluorescence emission. PMID:27280060

  17. Total light approach of time-domain fluorescence diffuse optical tomography.

    PubMed

    Marjono, Andhi; Yano, Akira; Okawa, Shinpei; Gao, Feng; Yamada, Yukio

    2008-09-15

    In this study, time-domain fluorescence diffuse optical tomography in biological tissue is numerically investigated using a total light approach. Total light is a summation of excitation light and zero-lifetime emission light divided by quantum yield. The zero-lifetime emission light is an emitted fluorescence light calculated by assuming that the fluorescence lifetime is zero. The zero-lifetime emission light is calculated by deconvolving the actually measured emission light with a lifetime function, an exponential function for fluorescence decay. The object for numerical simulation is a 2-D 10 mm-radius circle with the optical properties simulating biological tissues for near infrared light, and contains regions with fluorophore. The inverse problem of fluorescence diffuse optical tomography is solved using time-resolved simulated measurement data of the excitation and total lights for reconstructing the bsorption coefficient and fluorophore concentration simultaneously. The mean time of flight is used as the featured data-type extracted from the time-resolved data. The reconstructed images of fluorophore concentration show good quantitativeness and spatial reproducibility. By use of the total light approach, computation is performed much faster than the conventional ones.

  18. NMDA potentiation by visible light in the presence of a fluorescent neurosteroid analogue.

    PubMed

    Eisenman, Lawrence N; Shu, Hong-Jin; Wang, Cunde; Aizenman, Elias; Covey, Douglas F; Zorumski, Charles F; Mennerick, Steven

    2009-06-15

    N-Methyl-D-aspartate (NMDA) receptors are widely studied because of their importance in synaptic plasticity and excitotoxic cell death. Here we report a novel method of potentiating NMDA receptors with fluorescence excited by blue (480 nm) light. In the presence of 300 nM of a (7-nitro-2,1,3-benzoxadiazol-4-yl) amino (NBD)-tagged neuroactive steroid carrier C2-NBD-(3alpha,5alpha)-3-hydroxypregnan-20-one (C2-NBD 3alpha5alphaP), responses of cultured hippocampal neurons to 10 microM NMDA were potentiated to 219.2 +/- 9.2% of the baseline response (100%) by a 30 s exposure to 480 nm light. The potentiation decayed back to baseline with a time constant of 80.6 s. Responses to 1 microM and 100 microM NMDA were potentiated to 147.9 +/- 9.6% and 174.1 +/- 15.6% of baseline, respectively, suggesting that visible-light potentiation is relatively insensitive to NMDA concentration. Peak autaptic NMDA responses were potentiated to 178.9 +/- 22.4% of baseline. Similar potentiation was seen with 10 microM NBD-lysine, suggesting that visible-light potentiation is not a steroid effect. Potentiation was also seen with a steroid analogue in which the NBD was replaced with fluorescein, suggesting that NBD is not the only fluorophore capable of supporting visible-light potentiation. UV light and redox potentiation of NMDA receptors largely occluded subsequent blue light potentiation (127.7 +/- 7.4% and 120.2 +/- 6.2% of baseline, respectively). The NR1a(C744A,C798A) mutant that is insensitive to redox and UV potentiation was also largely unaffected by visible-light potentiation (135.0 +/- 10.0% of baseline). Finally, we found that the singlet oxygen scavenger furfuryl alcohol decreased visible-light potentiation. Collectively, these data suggest that visible-light potentiation of NMDA receptors by fluorescence excitation shares mechanisms with UV and redox potentiation and may involve singlet oxygen production.

  19. Impact of Fluorescent Lighting on Oxidation of Model Wine Solutions Containing Organic Acids and Iron.

    PubMed

    Grant-Preece, Paris; Barril, Celia; Schmidtke, Leigh M; Clark, Andrew C

    2017-03-22

    Previous studies have provided evidence that light exposure can increase oxygen consumption in wine and that the photodegradation of iron(III) tartrate could contribute to this process. In the present study, model wine solutions containing iron(III) and various organic acids, either alone or combined, were stored in sealed clear glass wine bottles and exposed to light from fluorescent lamps. Dissolved oxygen was monitored, and afterward the organic acid degradation products were determined and the capacity of the solutions to bind sulfur dioxide, the main wine preservative, was assessed. In the dark controls, little or no dissolved oxygen was consumed and the organic acids were stable. In the irradiated solutions, dissolved oxygen was consumed at a rate that was dependent on the specific organic acid present, and the latter were oxidized to various carbonyl compounds. For the solutions containing tartaric acid, malic acid, and/or citric acid, irradiation increased their sulfur dioxide-binding capacity.

  20. Deeper Insight into Fluorescence-Excitation of Molecules by Light

    ERIC Educational Resources Information Center

    Wahab, M. Farooq; Gore, Gordon R.

    2013-01-01

    In a recent issue of "TPT," Gordon Gore made interesting observations about the red or yellow fluorescence when laser beams are passed through olive oil. With the excellent visuals contained in that article, we present a pictorial explanation of the questions that were raised in Ref 1 ("Fun with Fluorescence in Olive Oil,"…

  1. Light-induced fluorescence endoscopy (LIFE) imaging system for early cancer detection

    NASA Astrophysics Data System (ADS)

    Zeng, Haishan; MacAulay, Calum E.; Lam, Stephen; Palcic, Branko

    1999-09-01

    This paper summarizes our experiences on the development of a Light Induced Fluorescence Endoscopy (LIFE) imaging system for early cancer detection in the respiratory and gastrointestinal tract. The system utilizes tissue autofluorescence to provide real time video imaging of the examined organ. No exogenous fluorescent tumor markers are needed. It is used by a physician in adjunct to conventional white-light endoscopy. Suspicious areas are identified in pseudo color to guide biopsy. A multi- center clinical trial has demonstrated that in the lung, the relative sensitivity of white-light imaging + LIFE imaging vs. white-light imaging alone was 6.3 for intraepithelial neoplastic lesion detection and 2.71 when invasive carcinomas were also included. The following issues will be discussed: (1) spectroscopy study design for imaging system development; (2) architecture of the imaging systems; (3) different imaging modalities (white-light imaging, dual channel fluorescence imaging, and combined fluorescence/reflectance imaging); and (4) clinical applications.

  2. Strong antenna-enhanced fluorescence of a single light-harvesting complex shows photon antibunching

    PubMed Central

    Wientjes, Emilie; Renger, Jan; Curto, Alberto G.; Cogdell, Richard; van Hulst, Niek F.

    2014-01-01

    The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of light-harvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna. The resonant antenna produces an excitation enhancement of circa 100 times and a fluorescence lifetime shortening to ~\

  3. White light-informed optical properties improve ultrasound-guided fluorescence tomography of photoactive protoporphyrin IX

    PubMed Central

    DSouza, Alisha V.; Kanick, Stephen C.; Davis, Scott C.; Pogue, Brian W.

    2013-01-01

    Abstract. Subsurface fluorescence imaging is desirable for medical applications, including protoporphyrin-IX (PpIX)-based skin tumor diagnosis, surgical guidance, and dosimetry in photodynamic therapy. While tissue optical properties and heterogeneities make true subsurface fluorescence mapping an ill-posed problem, ultrasound-guided fluorescence-tomography (USFT) provides regional fluorescence mapping. Here USFT is implemented with spectroscopic decoupling of fluorescence signals (auto-fluorescence, PpIX, photoproducts), and white light spectroscopy-determined bulk optical properties. Segmented US images provide a priori spatial information for fluorescence reconstruction using region-based, diffuse FT. The method was tested in simulations, tissue homogeneous and inclusion phantoms, and an injected-inclusion animal model. Reconstructed fluorescence yield was linear with PpIX concentration, including the lowest concentration used, 0.025  μg/ml. White light spectroscopy informed optical properties, which improved fluorescence reconstruction accuracy compared to the use of fixed, literature-based optical properties, reduced reconstruction error and reconstructed fluorescence standard deviation by factors of 8.9 and 2.0, respectively. Recovered contrast-to-background error was 25% and 74% for inclusion phantoms without and with a 2-mm skin-like layer, respectively. Preliminary mouse-model imaging demonstrated system feasibility for subsurface fluorescence measurement in vivo. These data suggest that this implementation of USFT is capable of regional PpIX mapping in human skin tumors during photodynamic therapy, to be used in dosimetric evaluations. PMID:23584445

  4. White light-informed optical properties improve ultrasound-guided fluorescence tomography of photoactive protoporphyrin IX

    NASA Astrophysics Data System (ADS)

    Flynn, Brendan P.; DSouza, Alisha V.; Kanick, Stephen C.; Davis, Scott C.; Pogue, Brian W.

    2013-04-01

    Subsurface fluorescence imaging is desirable for medical applications, including protoporphyrin-IX (PpIX)-based skin tumor diagnosis, surgical guidance, and dosimetry in photodynamic therapy. While tissue optical properties and heterogeneities make true subsurface fluorescence mapping an ill-posed problem, ultrasound-guided fluorescence-tomography (USFT) provides regional fluorescence mapping. Here USFT is implemented with spectroscopic decoupling of fluorescence signals (auto-fluorescence, PpIX, photoproducts), and white light spectroscopy-determined bulk optical properties. Segmented US images provide a priori spatial information for fluorescence reconstruction using region-based, diffuse FT. The method was tested in simulations, tissue homogeneous and inclusion phantoms, and an injected-inclusion animal model. Reconstructed fluorescence yield was linear with PpIX concentration, including the lowest concentration used, 0.025 μg/ml. White light spectroscopy informed optical properties, which improved fluorescence reconstruction accuracy compared to the use of fixed, literature-based optical properties, reduced reconstruction error and reconstructed fluorescence standard deviation by factors of 8.9 and 2.0, respectively. Recovered contrast-to-background error was 25% and 74% for inclusion phantoms without and with a 2-mm skin-like layer, respectively. Preliminary mouse-model imaging demonstrated system feasibility for subsurface fluorescence measurement in vivo. These data suggest that this implementation of USFT is capable of regional PpIX mapping in human skin tumors during photodynamic therapy, to be used in dosimetric evaluations.

  5. Fixation-resistant photoactivatable fluorescent proteins for correlative light and electron microscopy

    PubMed Central

    Paez Segala, Maria G.; Sun, Mei G.; Shtengel, Gleb; Viswanathan, Sarada; Baird, Michelle A.; Macklin, John J.; Patel, Ronak; Allen, John R.; Howe, Elizabeth S.; Piszczek, Grzegorz; Hess, Harald F.; Davidson, Michael W.; Wang, Yalin; Looger, Loren L.

    2014-01-01

    Fluorescent proteins facilitate a variety of imaging paradigms in live and fixed samples. However, they cease to function following heavy fixation, hindering advanced applications such as correlative light and electron microscopy. Here we report engineered variants of the photoconvertible Eos fluorescent protein that function normally in heavily fixed (0.5–1% OsO4), plastic resin-embedded samples, enabling correlative super-resolution fluorescence imaging and high-quality electron microscopy. PMID:25581799

  6. [Effects of different LED light qualities on photosynthetic characteristics, fruit production and quality of strawberry].

    PubMed

    Liu, Qing; Lian, Hai-feng; Liu, Shi-qi; Sun, Ya-li; Yu, Xin-hui; Guo, Hui-ping

    2015-06-01

    Taking 'Miaoxiang No.7' strawberry as material, full red light, full blue light, full yellow light, full white light, red/blue/yellow (7/2/1), red/blue (7/2) light generated by light emitting diode (LED) was applied to accurately modulate with white light generated as control. The indicators of photosynthetic and fluorescence parameters, pigment content, fruit production and quality, root activity were investigated. The effects of light quality under the light intensity (500 µmol · m(-2) · s(-1)) on the photosynthetic characteristic, fruit production and quality of strawberry were studied. The results showed that the red light could increase photosynthetic parameters (Pn, Tr), while blue light had inhibitory effect. Intercellular CO2 concentration (Ci) and conductance (g(s)) were the highest under blue light. The fluorescence parameters were significantly affected by light quality, Fo, Fm and Φ PS II the highest under red light, but values of the maximal photochemical of PS II (Fv/Fm), Fv/Fo and Fm/Fo highest under red/blue/yellow (7/2/1). In addition, the soluble solids content and vitamin C were highest under red light, the blue light could increase protein and titratable acid, sugar-acid ratio was the highest under red/blue/yellow (7/2/1). Comprehensive analysis indicated that red/blue/yellow (7/2/1) was more beneficial to the increase of pigment contents of leaves, fruit production and some qualities of strawberry.

  7. Energy Conservation Using Scotopically Enhanced Fluorescent Lighting In An Office Environment

    SciTech Connect

    2004-03-01

    This study was conducted in a recently built and occupied office building to determine whether the energy savings benefits of scotopically enhanced fluorescent lighting can be achieved while maintaining user acceptability.

  8. Cancer detection using NIR elastic light scattering and tissue fluorescence imaging

    SciTech Connect

    Demos, S G; Staggs, M; Radousky, H B; Gandour-Edwards, R; deVere White, R

    2000-12-04

    Near infrared imaging using elastic light scattering and tissue fluorescence under long-wavelength laser excitation are explored for cancer detection. Various types of normal and malignant human tissue samples were utilized in this investigation.

  9. Modulation of fluorescence signals from biomolecules along nanowires due to interaction of light with oriented nanostructures.

    PubMed

    Frederiksen, Rune S; Alarcon-Llado, Esther; Madsen, Morten H; Rostgaard, Katrine R; Krogstrup, Peter; Vosch, Tom; Nygård, Jesper; Fontcuberta I Morral, Anna; Martinez, Karen L

    2015-01-14

    High aspect ratio nanostructures have gained increasing interest as highly sensitive platforms for biosensing. Here, well-defined biofunctionalized vertical indium arsenide nanowires are used to map the interaction of light with nanowires depending on their orientation and the excitation wavelength. We show how nanowires act as antennas modifying the light distribution and the emitted fluorescence. This work highlights an important optical phenomenon in quantitative fluorescence studies and constitutes an important step for future studies using such nanostructures.

  10. Organic light-emitting device with a phosphor-sensitized fluorescent emission layer

    DOEpatents

    Forrest, Stephen; Kanno, Hiroshi

    2009-08-25

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters. The emissive region of the devices of the present invention comprise at least one phosphor-sensitized layer which has a combined emission from a phosphorescent emitter and a fluorescent emitter. In preferred embodiments, the invention relates to white-emitting OLEDS (WOLEDs).

  11. White light-emitting diode with quasisolar spectrum based on organic fluorescent dyes

    NASA Astrophysics Data System (ADS)

    Chung, Shuang-Chao; Li, Ming-Chia; Sun, Ching-Cherng

    2015-07-01

    We present a study of light-emitting diodes (LEDs) using organic fluorescent dyes to replace the general phosphor. The blue die with a specific organic fluorescent dye gives the LED a single color appearance. Through a color-mixing cavity, multiple LEDs are used to produce a quasisolar spectrum at a certain band and white light with a color rendering index as high as 97 at around 2800 K.

  12. Vibrio azureus emits blue-shifted light via an accessory blue fluorescent protein.

    PubMed

    Yoshizawa, Susumu; Karatani, Hajime; Wada, Minoru; Kogure, Kazuhiro

    2012-04-01

    Luminous marine bacteria usually emit bluish-green light with a peak emission wavelength (λ(max) ) at about 490 nm. Some species belonging to the genus Photobacterium are exceptions, producing an accessory blue fluorescent protein (lumazine protein: LumP) that causes a blue shift, from λ(max)  ≈ 490 to λ(max)  ≈ 476 nm. However, the incidence of blue-shifted light emission or the presence of accessory fluorescent proteins in bacteria of the genus Vibrio has never been reported. From our spectral analysis of light emitted by 16 luminous strains of the genus Vibrio, it was revealed that most strains of Vibrio azureus emit a blue-shifted light with a peak at approximately 472 nm, whereas other Vibrio strains emit light with a peak at around 482 nm. Therefore, we investigated the mechanism underlying this blue shift in V. azureus NBRC 104587(T) . Here, we describe the blue-shifted light emission spectra and the isolation of a blue fluorescent protein. Intracellular protein analyses showed that this strain had a blue fluorescent protein (that we termed VA-BFP), the fluorescent spectrum of which was almost identical to that of the in vivo light emission spectrum of the strain. This result strongly suggested that VA-BFP was responsible for the blue-shifted light emission of V. azureus.

  13. In Vivo Lighted Fluorescence via Fenton Reaction: Approach for Imaging of Hydrogen Peroxide in Living Systems.

    PubMed

    Liu, Changhui; Chen, Weiju; Qing, Zhihe; Zheng, Jing; Xiao, Yue; Yang, Sheng; Wang, Lili; Li, Yinhui; Yang, Ronghua

    2016-04-05

    By virtue of its high sensitivity and rapidity, Fenton reaction has been demonstrated as a powerful tool for in vitro biochemical analysis; however, in vivo applications of Fenton reaction still remain to be exploited. Herein, we report, for the first time, the design, formation and testing of Fenton reaction for in vivo fluorescence imaging of hydrogen peroxide (H2O2). To realize in vivo fluorescence imaging of H2O2 via Fenton reaction, a functional nanosphere, Fc@MSN-FDNA/PTAD, is fabricated from mesoporous silica nanoparticle (MSN), a Fenton reagent of ferrocene (Fc), ROX-labeled DNA (FDNA), and a cationic perylene derivative (PTAD). The ferrocene molecules are locked in the pore entrances of MSN, and exterior of MSN is covalently immobilized with FDNA. As a key part, PTAD acts as not only the gatekeeper of MSN but also the efficient quencher of ROX. H2O2 can permeate into the nanosphere and react with ferrocene to product hydroxyl radical (·OH) via Fenton reaction, which cleaves FDNA to detach ROX from PTAD, thus in turn, lights the ROX fluorescence. Under physiological condition, H2O2 can be determined from 5.0 nM to 1.0 μM with a detection limit of 2.4 nM. Because of the rapid kinetics of Fenton reaction and high specificity for H2O2, the proposed method meets the requirement for real applications. The feasibility of Fc@MSN-FDNA/PTAD for in vivo applications is demonstrated for fluorescence imaging of exogenous and endogenous H2O2 in cells and mice. We expect that this work will not only contribute to the H2O2-releated studies but also open up a new way to exploit in vivo Fenton reaction for biochemical research.

  14. On the advantages of using green light to study fluorescence yield changes in leaves.

    PubMed

    Rappaport, Fabrice; Béal, Daniel; Joliot, Anne; Joliot, Pierre

    2007-01-01

    In photosynthetic chains, the kinetics of fluorescence yield depends on the photochemical rates at the level of both Photosystem I and II and thus on the absorption cross section of the photosynthetic units as well as on the coupling between light harvesting complexes and photosynthetic traps. A new set-up is described which, at variance with the commonly used set-ups, uses of a weakly absorbed light source (light-emitting diodes with maximum output at 520 nm) to excite the photosynthetic electron chain and probe the resulting fluorescence yield changes and their time course. This approach optimizes the homogeneity of the exciting light throughout the leaf and we show that this homogeneity narrows the distribution of the photochemical rates. Although the exciting light is weakly absorbed, the possibility to tune the intensity of the light emitting diodes allows one to reach photochemical rates ranging from 10(4) s(-1) to 0.25 s(-1) rendering experimentally accessible different functional regimes. The variations of the fluorescence yield induced by the photosynthetic activity are qualitatively and quantitatively discussed. When illuminating dark-adapted leaves by a weak light, the kinetics of fluorescence changes displays a pronounced plateau which precedes the fluorescence increase reflecting the full reduction of the plastoquinone pool. We ascribe this plateau to the time delay needed to reduce the photosystem I electron acceptors.

  15. Regulation of red fluorescent light emission in a cryptic marine fish

    PubMed Central

    2014-01-01

    Introduction Animal colouration is a trade-off between being seen by intended, intra- or inter-specific receivers while not being seen by the unintended. Many fishes solve this problem by adaptive colouration. Here, we investigate whether this also holds for fluorescent pigments. In those aquatic environments in which the ambient light is dominated by bluish light, red fluorescence can generate high-contrast signals. The marine, cryptic fish Tripterygion delaisi inhabits such environments and has a bright red-fluorescent iris that can be rapidly up- and down-regulated. Here, we described the physiological and cellular mechanism of this phenomenon using a neurostimulation treatment with KCl and histology. Results KCl-treatment revealed that eye fluorescence regulation is achieved through dispersal and aggregation of black-pigmented melanosomes within melanophores. Histology showed that globular, fluorescent iridophores on the anterior side of the iris are grouped and each group is encased by finger-like extensions of a single posterior melanophore. Together they form a so-called chromatophore unit. By dispersal and aggregation of melanosomes into and out of the peripheral membranous extensions of the melanophore, the fluorescent iridophores are covered or revealed on the anterior (outside) of the iris. Conclusion T. delaisi possesses a well-developed mechanism to control the fluorescent emission from its eyes, which may be advantageous given its cryptic lifestyle. This is the first time chromatophore units are found to control fluorescent emission in marine teleost fishes. We expect other fluorescent fish species to use similar mechanisms in the iris or elsewhere in the body. In contrast to a previously described mechanism based on dendritic fluorescent chromatophores, chromatophore units control fluorescent emission through the cooperation between two chromatophore types: an emitting and an occluding type. The discovery of a second mechanism for fluorescence

  16. UV/blue light-induced fluorescence for assessing apple maturity

    NASA Astrophysics Data System (ADS)

    Noh, Hyun Kwon; Lu, Renfu

    2005-11-01

    Chlorophyll fluorescence has been researched for assessing fruit post-harvest quality and condition. The objective of this preliminary research was to investigate the potential of fluorescence spectroscopy for measuring apple fruit quality. Ultraviolet (UV) and blue light was used as an excitation source for inducing fluorescence in apples. Fluorescence spectra were measured from 'Golden Delicious' (GD) and 'Red Delicious' (RD) apples by using a visible/near-infrared spectrometer after one, three, and five minutes of continuous UV/blue light illumination. Standard destructive tests were performed to measure fruit firmness, skin and flesh color, soluble solids and acid content from the apples. Calibration models for each of the three illumination time periods were developed to predict fruit quality indexes. The results showed that fluorescence emission decreased steadily during the first three minutes of UV/blue light illumination and was stable within five minutes. The differences were minimal in the model prediction results based on fluorescence data at one, three or five minutes of illumination. Overall, better predictions were obtained for apple skin chroma and hue and flesh hue with values for the correlation coefficient of validation between 0.80 and 0.90 for both GD and RD. Relatively poor predictions were obtained for fruit firmness, soluble solids content, titrational acid, and flesh chroma. This research demonstrated that fluorescence spectroscopy is potentially useful for assessing selected quality attributes of apple fruit and further research is needed to improve fluorescence measurements so that better predictions of fruit quality can be achieved.

  17. Red fluorescence of the triplefin Tripterygion delaisi is increasingly visible against background light with increasing depth

    PubMed Central

    Harant, Ulrike K.; Fritsch, Roland; Michiels, Nico K.

    2017-01-01

    The light environment in water bodies changes with depth due to the absorption of short and long wavelengths. Below 10 m depth, red wavelengths are almost completely absent rendering any red-reflecting animal dark and achromatic. However, fluorescence may produce red coloration even when red light is not available for reflection. A large number of marine taxa including over 270 fish species are known to produce red fluorescence, yet it is unclear under which natural light environment fluorescence contributes perceptively to their colours. To address this question we: (i) characterized the visual system of Tripterygion delaisi, which possesses fluorescent irides, (ii) separated the colour of the irides into its reflectance and fluorescence components and (iii) combined these data with field measurements of the ambient light environment to calculate depth-dependent perceptual chromatic and achromatic contrasts using visual modelling. We found that triplefins have cones with at least three different spectral sensitivities, including differences between the two members of the double cones, giving them the potential for trichromatic colour vision. We also show that fluorescence contributes increasingly to the radiance of the irides with increasing depth. Our results support the potential functionality of red fluorescence, including communicative roles such as species and sex identity, and non-communicative roles such as camouflage.

  18. Light illumination and detection patterns for fluorescence diffuse optical tomography based on compressive sensing.

    PubMed

    Jin, An; Yazici, Birsen; Ntziachristos, Vasilis

    2014-06-01

    Fluorescence diffuse optical tomography (FDOT) is an emerging molecular imaging modality that uses near infrared light to excite the fluorophore injected into tissue; and to reconstruct the fluorophore concentration from boundary measurements. The FDOT image reconstruction is a highly ill-posed inverse problem due to a large number of unknowns and limited number of measurements. However, the fluorophore distribution is often very sparse in the imaging domain since fluorophores are typically designed to accumulate in relatively small regions. In this paper, we use compressive sensing (CS) framework to design light illumination and detection patterns to improve the reconstruction of sparse fluorophore concentration. Unlike the conventional FDOT imaging where spatially distributed light sources illuminate the imaging domain one at a time and the corresponding boundary measurements are used for image reconstruction, we assume that the light sources illuminate the imaging domain simultaneously several times and the corresponding boundary measurements are linearly filtered prior to image reconstruction. We design a set of optical intensities (illumination patterns) and a linear filter (detection pattern) applied to the boundary measurements to improve the reconstruction of sparse fluorophore concentration maps. We show that the FDOT sensing matrix can be expressed as a columnwise Kronecker product of two matrices determined by the excitation and emission light fields. We derive relationships between the incoherence of the FDOT forward matrix and these two matrices, and use these results to reduce the incoherence of the FDOT forward matrix. We present extensive numerical simulation and the results of a real phantom experiment to demonstrate the improvements in image reconstruction due to the CS-based light illumination and detection patterns in conjunction with relaxation and greedy-type reconstruction algorithms.

  19. Implantable biosensors: analysis of fluorescent light propagation through skin

    NASA Astrophysics Data System (ADS)

    O'Neal, D. P.; McShane, Michael J.; Pishko, Michael V.; Cote, Gerard L.

    2001-06-01

    Progress towards a painless and hygienic glucose monitoring procedure for diabetics continues as the growth of diabetes mellitus reaches epidemic proportions in the American population. Utilizing an implantable fluorescence based glucose assay, the minimally invasive approach presented here has previously shown promise towards this goal in terms of glucose specificity and quantification for in vitro environments. However, in realistic physiological circumstances the depth of the implant can vary and optical properties of skin can change due to normal physiological conditions. Additionally, naturally occurring auto-fluorescence can obscure the sensor signal. An important concern under these conditions is that variations of fluorescent intensity due to these or other causes might be mistaken for glucose concentration fluctuations. New data shows that fluorescence-based glucose assays can be probed and interpreted in terms of glucose concentrations through pig skin at depths of up to 700 mm when immobilized in a bio-compatible polymer. When a combination of two fluorophores are employed as demonstrated here, reasonable changes in skin thickness and the confounding effects of the variations inherent in skin can be overcome for this glucose sensing application.

  20. Deeper Insight into Fluorescence--Excitation of Molecules by Light

    NASA Astrophysics Data System (ADS)

    Wahab, M. Farooq; Gore, Gordon R.

    2013-05-01

    In a recent issue of TPT, Gordon Gore made interesting observations about the red or yellow fluorescence when laser beams are passed through olive oil. With the excellent visuals contained in that article, we present a pictorial explanation of the questions that were raised in Ref 1.

  1. Fluorescence enhancement and reflection of the excitation light observed with a multilayered substrate.

    PubMed

    Akimoto, Takuo; Yasuda, Mitsuru

    2010-01-01

    Fluorescence enhancement from a multilayered substrate fabricated with Ag and Al(2)O(3) was investigated using fluorescein, rhodamine B, Cy3, and Cy5 as fluorophores. The change in the fluorescence enhancement with Al(2)O(3) had two peaks and one valley in the range from 0 to 300 nm of Al(2)O(3) thickness, and such peaks and valley were found to appear periodically. Moreover, the reflection of the excitation light from the multilayered substrate was investigated. The reflection of the excitation light periodically changed depending on the Al(2)O(3) thickness as well, and the maximum reflection was observed near the Al(2)O(3) thickness of the peak fluorescence enhancement. It was found that the periodic changes of the fluorescence enhancement and the reflection of the excitation light could be explained, for the most part, with the integral multiples of the lambda/4 derived by a simple interference theory.

  2. Angular distribution of light emission from compound-eye cornea with conformal fluorescent coating

    NASA Astrophysics Data System (ADS)

    Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

    2014-09-01

    The complex morphology of the apposition compound eyes of insects of many species provides them a wide angular field of view. This characteristic makes these eyes attractive for bioreplication as artificial sources of light. The cornea of a blowfly eye was conformally coated with a fluorescent thin film with the aim of achieving wide field-of-view emission. On illumination by shortwave-ultraviolet light, the conformally coated eye emitted visible light whose intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  3. Highly bright broadband red light produced by fluorescence polymer/InGaN hybrid light-emitting diodes.

    PubMed

    Lai, Chun-Feng; Chang, Chi-Jung; Hsieh, Cheng-Liang; Chen, Yung-Lin; Tuan, Chi-Shen

    2013-10-15

    The fabrication of fluorescence polymer/InGaN hybrid light-emitting diodes (LEDs) that emit highly bright broadband red light is presented in this Letter. The absorption peak of the fluorescence polymer was 455 nm, and the emission peak was 640 nm. The light output power and external quantum efficiency of hybrid LEDs at a driving current of 100 mA were 46.6 mW and 24.1%, respectively. The emission spectrum of hybrid LEDs was located at a wavelength of 641 nm, with a broadband FWHM of 106 nm. Thus this study offers potential methods for enhancing the output power of commercial white-light-emitting devices.

  4. [Effect of Methylmercury on the Light Dependence Fluorescence Parameters in a Green Alga Chlamydomonas moewusii].

    PubMed

    Protopopov, F F; Matorin, D N; Seifullina, N H; Bratkovskaya, L B; Zayadan, B K

    2015-01-01

    The effect of a dangerous toxic substance, methylmercury, on light dependence curves of chlorophyll fluorescence in Chlamydomonas moewusii was studied. We found low concentration of methylmercury (10(-7) M) to cause a decrease in the relative rate of the non-cyclic electron transport activity of PS 2, a decline in the maximum utilization of light energy (α), and a decline in the saturation light intensity (E(s)). Non-photochemical fluorescence quenching increased after short-term exposure and decreased in the course of prolonged incubation. These parameters were more sensitive to the action of the toxic substance than the widely used parameter F(V)/F(M), which reflects the maximum quantum yield of PS 2. We propose the use of the method of fast measurement of light dependence curves of fluorescence to detect the changes in algal cells at the early stages of exposure to mercury salts.

  5. Cobalt phosphide nanowires: efficient nanostructures for fluorescence sensing of biomolecules and photocatalytic evolution of dihydrogen from water under visible light.

    PubMed

    Tian, Jingqi; Cheng, Ningyan; Liu, Qian; Xing, Wei; Sun, Xuping

    2015-04-27

    The detection of specific DNA sequences plays an important role in the identification of disease-causing pathogens and genetic diseases, and photochemical water splitting offers a promising avenue to sustainable, environmentally friendly hydrogen production. Cobalt-phosphorus nanowires (CoP NWs) show a high fluorescence quenching ability and different affinity toward single- versus double-stranded DNA. Based on this result, the utilization of CoP NWs as fluorescent DNA nanosensors with a detection limit of 100 pM and a selectivity down to single-base mismatch was demonstrated. The use of a thrombin-specific DNA aptamer also enabled the selective detection of thrombin. The photoinduced electron transfer from the excited dye that labels the oligonucleotide probe to the CoP semiconductor led to efficient fluorescence quenching, and largely enhanced the photocatalytic evolution of hydrogen from water under visible light.

  6. Variability in chlorophyll fluorescence spectra of eggplant fruit grown under different light environments: a case study.

    PubMed

    Ospina Calvo, Brian; Parapugna, Tamara L; Lagorio, M Gabriela

    2017-03-13

    The main goal of the present work was to clarify physiological strategies in plants whose chloroplasts were developed under different light environments. The specific objective was to elucidate the influence of the spectral distribution of light on the chlorophyll fluorescence ratio and on photosynthetic parameters. To achieve this purpose, three species of eggplant fruit (black, purple and white striped and white) were used as a case study and their chlorophyll fluorescence was analyzed in detail. Spectra of the non-variable fluorescence in each part of the fruit were corrected for distortions by light reabsorption processes using a physical model. The main conclusion of this work was that the corrected fluorescence ratio was dependent on the contribution of each photosystem to the fluorescence and consequently on the environmental lighting conditions, becoming higher when illumination was rich in long wavelengths. Variable chlorophyll fluorescence, similar to that observed from plant leaves, was detected for the pulp of the black eggplant, for the pulp of the purple and white striped eggplant and for the intact fruit of the black eggplant. The maximum quantum efficiency of photosystem II in the light-adapted state (F'v/F'm), the quantum efficiency of photosystem II (ΦPSII), and the photochemical and non-photochemical quenching coefficients (qP and qNP/NPQ respectively) were determined in each case. The results could be explained very interestingly, in relation with the proportion of exciting light reaching each photosystem (I and II). The photochemical parameters obtained from variable chlorophyll fluorescence, allowed us to monitor non-destructively the physiological state of the black fruit during storage under both chilled or room-temperature conditions.

  7. Separation of ballistic and diffusive fluorescence photons in confocal Light-Sheet Microscopy of Arabidopsis roots

    NASA Astrophysics Data System (ADS)

    Meinert, Tobias; Tietz, Olaf; Palme, Klaus J.; Rohrbach, Alexander

    2016-08-01

    Image quality in light-sheet fluorescence microscopy is strongly affected by the shape of the illuminating laser beam inside embryos, plants or tissue. While the phase of Gaussian or Bessel beams propagating through thousands of cells can be partly controlled holographically, the propagation of fluorescence light to the detector is difficult to control. With each scatter process a fluorescence photon loses information necessary for the image generation. Using Arabidopsis root tips we demonstrate that ballistic and diffusive fluorescence photons can be separated by analyzing the image spectra in each plane without a priori knowledge. We introduce a theoretical model allowing to extract typical scattering parameters of the biological material. This allows to attenuate image contributions from diffusive photons and to amplify the relevant image contributions from ballistic photons through a depth dependent deconvolution. In consequence, image contrast and resolution are significantly increased and scattering artefacts are minimized especially for Bessel beams with confocal line detection.

  8. Separation of ballistic and diffusive fluorescence photons in confocal Light-Sheet Microscopy of Arabidopsis roots

    PubMed Central

    Meinert, Tobias; Tietz, Olaf; Palme, Klaus J.; Rohrbach, Alexander

    2016-01-01

    Image quality in light-sheet fluorescence microscopy is strongly affected by the shape of the illuminating laser beam inside embryos, plants or tissue. While the phase of Gaussian or Bessel beams propagating through thousands of cells can be partly controlled holographically, the propagation of fluorescence light to the detector is difficult to control. With each scatter process a fluorescence photon loses information necessary for the image generation. Using Arabidopsis root tips we demonstrate that ballistic and diffusive fluorescence photons can be separated by analyzing the image spectra in each plane without a priori knowledge. We introduce a theoretical model allowing to extract typical scattering parameters of the biological material. This allows to attenuate image contributions from diffusive photons and to amplify the relevant image contributions from ballistic photons through a depth dependent deconvolution. In consequence, image contrast and resolution are significantly increased and scattering artefacts are minimized especially for Bessel beams with confocal line detection. PMID:27553506

  9. Light propagation and fluorescence quantum yields in liquid scintillators

    NASA Astrophysics Data System (ADS)

    Buck, C.; Gramlich, B.; Wagner, S.

    2015-09-01

    For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.

  10. A visible-light-excited fluorescence method for imaging protein crystals without added dyes.

    PubMed

    Lukk, Tiit; Gillilan, Richard E; Szebenyi, Doletha M E; Zipfel, Warren R

    2016-02-01

    Fluorescence microscopy methods have seen an increase in popularity in recent years for detecting protein crystals in screening trays. The fluorescence-based crystal detection methods have thus far relied on intrinsic UV-inducible tryptophan fluorescence, nonlinear optics or fluorescence in the visible light range dependent on crystals soaked with fluorescent dyes. In this paper data are presented on a novel visible-light-inducible autofluorescence arising from protein crystals as a result of general stabilization of conjugated double-bond systems and increased charge delocalization due to crystal packing. The visible-light-inducible autofluorescence serves as a complementary method to bright-field microscopy in beamline applications where accurate crystal centering about the rotation axis is essential. Owing to temperature-dependent chromophore stabilization, protein crystals exhibit tenfold higher fluorescence intensity at cryogenic temperatures, making the method ideal for experiments where crystals are cooled to 100 K with a cryostream. In addition to the non-damaging excitation wavelength and low laser power required for imaging, the method can also serve a useful role for differentiating protein crystals from salt crystals in screening trays.

  11. Metal-enhanced fluorescence of chlorophylls in light-harvesting complexes coupled to silver nanowires.

    PubMed

    Kowalska, Dorota; Krajnik, Bartosz; Olejnik, Maria; Twardowska, Magdalena; Czechowski, Nikodem; Hofmann, Eckhard; Mackowski, Sebastian

    2013-01-01

    We investigate metal-enhanced fluorescence of peridinin-chlorophyll protein coupled to silver nanowires using optical microscopy combined with spectrally and time-resolved fluorescence techniques. In particular we study two different sample geometries: first, in which the light-harvesting complexes are deposited onto silver nanowires, and second, where solution of both nanostructures are mixed prior deposition on a substrate. The results indicate that for the peridinin-chlorophyll complexes placed in the vicinity of the silver nanowires we observe higher intensities of fluorescence emission as compared to the reference sample, where no nanowires are present. Enhancement factors estimated for the sample where the light-harvesting complexes are mixed together with the silver nanowires prior deposition on a substrate are generally larger in comparison to the other geometry of a hybrid nanostructure. While fluorescence spectra are identical both in terms of overall shape and maximum wavelength for peridinin-chlorophyll-protein complexes both isolated and coupled to metallic nanostructures, we conclude that interaction with plasmon excitations in the latter remains neutral to the functionality of the biological system. Fluorescence transients measured for the PCP complexes coupled to the silver nanowires indicate shortening of the fluorescence lifetime pointing towards modifications of radiative rate due to plasmonic interactions. Our results can be applied for developing ways to plasmonically control the light-harvesting capability of photosynthetic complexes.

  12. A visible-light-excited fluorescence method for imaging protein crystals without added dyes

    PubMed Central

    Lukk, Tiit; Gillilan, Richard E.; Szebenyi, Doletha M. E.; Zipfel, Warren R.

    2016-01-01

    Fluorescence microscopy methods have seen an increase in popularity in recent years for detecting protein crystals in screening trays. The fluorescence-based crystal detection methods have thus far relied on intrinsic UV-inducible tryptophan fluorescence, nonlinear optics or fluorescence in the visible light range dependent on crystals soaked with fluorescent dyes. In this paper data are presented on a novel visible-light-inducible autofluorescence arising from protein crystals as a result of general stabilization of conjugated double-bond systems and increased charge delocalization due to crystal packing. The visible-light-inducible autofluorescence serves as a complementary method to bright-field microscopy in beamline applications where accurate crystal centering about the rotation axis is essential. Owing to temperature-dependent chromophore stabilization, protein crystals exhibit tenfold higher fluorescence intensity at cryogenic temperatures, making the method ideal for experiments where crystals are cooled to 100 K with a cryostream. In addition to the non-damaging excitation wavelength and low laser power required for imaging, the method can also serve a useful role for differentiating protein crystals from salt crystals in screening trays. PMID:26937240

  13. Light adaptation of the unicellular red alga, Cyanidioschyzon merolae, probed by time-resolved fluorescence spectroscopy.

    PubMed

    Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

    2015-08-01

    Photosynthetic organisms change the quantity and/or quality of their pigment-protein complexes and the interactions among these complexes in response to light conditions. In the present study, we analyzed light adaptation of the unicellular red alga Cyanidioschyzon merolae, whose pigment composition is similar to that of cyanobacteria because its phycobilisomes (PBS) lack phycoerythrin. C. merolae were grown under different light qualities, and their responses were measured by steady-state absorption, steady-state fluorescence, and picosecond time-resolved fluorescence spectroscopies. Cells were cultivated under four monochromatic light-emitting diodes (blue, green, yellow, and red), and changes in pigment composition and energy transfer were observed. Cells grown under blue and green light increased their relative phycocyanin levels compared with cells cultured under white light. Energy-transfer processes to photosystem I (PSI) were sensitive to yellow and red light. The contribution of direct energy transfer from PBS to PSI increased only under yellow light, while red light induced a reduction in energy transfer from photosystem II to PSI and an increase in energy transfer from light-harvesting chlorophyll protein complex I to PSI. Differences in pigment composition, growth, and energy transfer under different light qualities are discussed.

  14. Quantitative in vivo imaging of entire embryos with Digital Scanned Laser Light Sheet Fluorescence Microscopy.

    PubMed

    Keller, Philipp J; Stelzer, Ernst H K

    2008-12-01

    The observation of biological processes in their natural in vivo context is a key requirement for quantitative experimental studies in the life sciences. In many instances, it will be crucial to achieve high temporal and spatial resolution over long periods of time without compromising the physiological development of the specimen. Here, we discuss the principles underlying light sheet-based fluorescence microscopes. The most recent implementation DSLM is a tool optimized to deliver quantitative data for entire embryos at high spatio-temporal resolution. We compare DSLM to the two established light microscopy techniques: confocal and two-photon fluorescence microscopy. DSLM provides up to 50 times higher imaging speeds and a 10-100 times higher signal-to-noise ratio, while exposing the specimens to at least three orders of magnitude less light energy than confocal and two-photon fluorescence microscopes. We conclude with a perspective for future development.

  15. Investigation of Relative Illuminance as a Function of Distance between Reflector and Fluorescent Light Source

    NASA Astrophysics Data System (ADS)

    Softic, Amela

    2007-04-01

    Although fluorescent lighting is considerably more efficient then incandescent, and is in wide use, manufacturers find new ways to improve its configuration and reduce energy use. Based on the fundamentals of ``Non-imaging Optics'', was experimentally investigated the dependence of illumination of a point in the space on the distance between the reflection and fluorescent light source. Monitoring of changes in illumination is performed by optical sensor and corresponding computer software. Investigation of the influence of the distance between the fluorescent light and the reflector on the relative illumination has shown, for the tested geometries, that by reducing the distance between them the illumination increased, even though the distance among the source and the measuring point got greater.

  16. Up-converted fluorescence from photosynthetic light-harvesting complexes linearly dependent on excitation intensity.

    PubMed

    Leiger, Kristjan; Freiberg, Arvi

    2016-01-01

    Weak up-converted fluorescence related to bacteriochlorophyll a was recorded from various detergent-isolated and membrane-embedded light-harvesting pigment-protein complexes as well as from the functional membranes of photosynthetic purple bacteria under continuous-wave infrared laser excitation at 1064 nm, far outside the optically allowed singlet absorption bands of the chromophore. The fluorescence increases linearly with the excitation power, distinguishing it from the previously observed two-photon excited fluorescence upon femtosecond pulse excitation. Possible mechanisms of this excitation are discussed.

  17. Fluorescence enhancement of light-harvesting complex 2 from purple bacteria coupled to spherical gold nanoparticles

    SciTech Connect

    Bujak, Ł.; Czechowski, N.; Piatkowski, D.; Litvin, R.; Mackowski, S.; Brotosudarmo, T. H. P.; Pichler, S.; Cogdell, R. J.; Heiss, W.

    2011-10-24

    The influence of plasmon excitations in spherical gold nanoparticles on the optical properties of a light-harvesting complex 2 (LH2) from the purple bacteria Rhodopseudomonas palustris has been studied. Systematic analysis is facilitated by controlling the thickness of a silica layer between Au nanoparticles and LH2 complexes. Fluorescence of LH2 complexes features substantial increase when these complexes are separated by 12 nm from the gold nanoparticles. At shorter distances, non-radiative quenching leads to a decrease of fluorescence emission. The enhancement of fluorescence originates predominantly from an increase of absorption of pigments comprising the LH2 complex.

  18. Molecular basis of the light-driven switching of the photochromic fluorescent protein Padron.

    PubMed

    Brakemann, Tanja; Weber, Gert; Andresen, Martin; Groenhof, Gerrit; Stiel, Andre C; Trowitzsch, Simon; Eggeling, Christian; Grubmüller, Helmut; Hell, Stefan W; Wahl, Markus C; Jakobs, Stefan

    2010-05-07

    Reversibly switchable fluorescent proteins can be repeatedly photoswitched between a fluorescent and a nonfluorescent state by irradiation with the light of two different wavelengths. The molecular basis of the switching process remains a controversial topic. Padron0.9 is a reversibly switchable fluorescent protein with "positive" switching characteristics, exhibiting excellent spectroscopic properties. Its chromophore is formed by the amino acids Cys-Tyr-Gly. We obtained high resolution x-ray structures of Padron0.9 in both the fluorescent and the nonfluorescent states and used the structural information for molecular dynamics simulations. We found that in Padron0.9 the chromophore undergoes a cis-trans isomerization upon photoswitching. The molecular dynamics simulations clarified the protonation states of the amino acid residues within the chromophore pocket that influence the protonation state of the chromophore. We conclude that a light driven cis-trans isomerization of the chromophore appears to be the fundamental switching mechanism in all photochromic fluorescent proteins known to date. Distinct absorption cross-sections for the switching wavelengths in the fluorescent and the nonfluorescent state are not essential for efficient photochromism in fluorescent proteins, although they may facilitate the switching process.

  19. Combination of normal light and fluorescence microscopy for authentication of five Lonicera species flower buds.

    PubMed

    Chu, Chu; Liu, Hui-Juan; Qi, Lian-Wen; Liu, E-Hu; Li, Ping

    2011-02-01

    The flower buds of five Lonicera species, Lonicera japonica Thunb., L. macranthoides Hand.-Mazz., L. hypoglauca Miq., L. confusa DC. and L. fulvotomentosa Hsu et S.C. Cheng are confusable and usually utilized under the same name "Jinyinhua" in different areas for morphological similarity. Studies found that these five species possess extreme differences in chemical compounds, correspondingly showing different pharmacological activities and clinical applications. To ensure efficacy and safety of these herbal medicines and prevent unknown adverse effect, in this work, a simple, rapid and effective method combining normal light and fluorescence microscopy was developed for authentication. Surface slides and transverse sections of these buds were investigated to reveal their differences. As a routine technique, normal light microscopy which gives detailed microscopic features such as glandular hairs and nonglandular hairs, can easily distinguish four species except L. confusa. Fluorescence technique, which could present different distribution of fluorescence materials, is further employed to identify three species including L. confusa successfully. It is the first report to identify these five Lonicera species by combining normal light and fluorescence microscopy. This work indicated combining normal light and fluorescence microscopy could be a powerful method in authentication of confused species.

  20. High efficiency and brightness fluorescent organic light emitting diode by triplet-triplet fusion

    DOEpatents

    Forrest, Stephen; Zhang, Yifan

    2015-02-10

    A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer may include an organic host compound and at least one organic emitting compound capable of fluorescent emission at room temperature. Various configurations are described for providing a range of current densities in which T-T fusion dominates over S-T annihilation, leading to very high efficiency fluorescent OLEDs.

  1. Iron oxide nanozyme catalyzed synthesis of fluorescent polydopamine for light-up Zn2+ detection

    NASA Astrophysics Data System (ADS)

    Liu, Biwu; Han, Xiao; Liu, Juewen

    2016-07-01

    Fluorescent polydopamine (FPD) is an interesting material with excellent biocompatibility. However, its preparation is currently a lengthy and potentially dangerous process. We herein employ magnetic iron oxide (Fe3O4) nanoparticles as a peroxidase-mimicking nanozyme to produce FPD under mild conditions. Different from previous protocols using multiple steps with up to 6% (~2 M) H2O2, this preparation takes place in a single step with just 5 mM H2O2 at room temperature. The oxidized product shows excitation-wavelength-dependent emission peaks, similar to previous reports. The reaction kinetics, pH, temperature, and ionic strength are individually optimized. Among a diverse range of other nanomaterials tested, including Fe2O3, CeO2, CoO, Co3O4, NiO, TiO2, gold nanoparticles, and graphene oxide, Fe2O3 and graphene oxide yielded relatively weak emission, while the rest of the materials failed to produce FPD. The Fe3O4 nanoparticles retained ~90% catalytic activity even after ten cycles of synthesis. Finally, Zn2+ can enhance the fluorescence of FPD under 360 nm excitation but not under 480 nm excitation, leading to a sensitive light-up sensor with a detection limit of 60 nM Zn2+. Therefore, this work has demonstrated not only a novel use of nanozymes, but also an interesting application of FPD.Fluorescent polydopamine (FPD) is an interesting material with excellent biocompatibility. However, its preparation is currently a lengthy and potentially dangerous process. We herein employ magnetic iron oxide (Fe3O4) nanoparticles as a peroxidase-mimicking nanozyme to produce FPD under mild conditions. Different from previous protocols using multiple steps with up to 6% (~2 M) H2O2, this preparation takes place in a single step with just 5 mM H2O2 at room temperature. The oxidized product shows excitation-wavelength-dependent emission peaks, similar to previous reports. The reaction kinetics, pH, temperature, and ionic strength are individually optimized. Among a diverse range

  2. Supplemental photosynthetic lighting for greenhouse tomato production

    SciTech Connect

    Godfriaux, B.L.; Wittman, W.K. ); Janes, H.W.; McAvoy, R.J.; Putman, J.; Logendra, S. . Dept. of Horticulture and Forestry); Mears, D.R.; Giacommelli, G.; Giniger, M. . Dept. of Biological and Agricultural Engineering)

    1989-12-01

    The influence of supplemental light on the growth and productivity of greenhouse tomatoes grown to a single cluster on movable benches is examined, and the economic feasibility of such a system is evaluated. Experiments were conducted to quantify the tomato plants' response to various levels of supplemental light in terms of growth rate and yield at various stages in their development (e.g., seedling, flowering plant, etc.). The 1984--85 experiments showed that supplemental photosynthetic lighting nearly doubled tomato yields, from 0.48 to 0.86 lbs/plant. Subsequent experiments in 1985--86 identified the best tomato varieties for this treatment and further increased yields to 1.3 lbs/plant. In addition, the use of supplemental lighting was found to hasten tomato crop maturity. An economic analysis was performed on the 1985--86 empirical data using the tax rates and provisions then in force. It indicated that a 10-acre greenhouse could provide an after-tax internal rate of return of 10% to 12% using only equity financing. This return could likely be increased to 15--18% with the use of combined debt/equity financing. Using supplemental lighting on 10,000 acres of greenhouse production would require an estimated 7.5 billion kWh of additional electricity per year and, at 4.7 cents/kWh, generate an estimated $350 million in additional utility revenues. 48 refs., 34 figs., 24 tabs.

  3. Enhanced biomass production and lipid accumulation of Picochlorum atomus using light-emitting diodes (LEDs).

    PubMed

    Ra, Chae Hun; Kang, Chang-Han; Jung, Jang-Hyun; Jeong, Gwi-Taek; Kim, Sung-Koo

    2016-10-01

    The effects of light-emitting diode (LED) wavelength, light intensity, nitrate concentration, and time of exposure to different LED wavelength stresses in a two-phase culture on lipid production were evaluated in the microalga, Picochlorum atomus. The biomass produced by red LED light was higher than that produced by purple, blue, green, or yellow LED and fluorescent lights from first phase of two-phase culture. The highest lipid production of P. atomus was 50.3% (w/w) with green LED light at 2days of second phase as light stress. Fatty acid analysis of the microalgae showed that palmitic acid (C16:0) and linolenic acid (C18:3) accounted for 84-88% (w/w) of total fatty acids from P. atomus. The two-phase culture of P. atomus is suitable for biofuel production due to higher lipid productivity and favorable fatty acid composition.

  4. Chemical nature of the light emitter of the Aequorea green fluorescent protein.

    PubMed

    Niwa, H; Inouye, S; Hirano, T; Matsuno, T; Kojima, S; Kubota, M; Ohashi, M; Tsuji, F I

    1996-11-26

    The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda max = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser65-Tyr66-Gly67-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced. To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore. The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore. Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission.

  5. In situ response of phytoplankton fluorescence to rapid variations in light

    SciTech Connect

    Abbott, M.R.; Richerson, P.J.; Powell, T.M.

    1982-03-01

    Phytoplankton chlorophyll a fluorescence responded to rapid fluctuations in light intensity in Lake Tahoe at three depths: 10, 35, and 60 m. Fluroescence yield was negatively correlated with surface irradiance at all depths, but there was a strong depth dependence in the intensity of this response. Phytoplankton at 35 m reacted more strongly to fluctuations than those at 10 or 60 m and therefore could show a noticeable response to more rapid variations. This may have been due to near-optimal light levels at 35 m, light inhibition at 10, and light limitation at 60 m.

  6. Mechanistic studies of the genetically encoded fluorescent protein voltage probe ArcLight.

    PubMed

    Han, Zhou; Jin, Lei; Chen, Fuyi; Loturco, Joseph J; Cohen, Lawrence B; Bondar, Alexey; Lazar, Josef; Pieribone, Vincent A

    2014-01-01

    ArcLight, a genetically encoded fluorescent protein voltage probe with a large ΔF/ΔV, is a fusion between the voltage sensing domain of the Ciona instestinalis voltage sensitive phosphatase and super ecliptic pHluorin carrying a single mutation (A227D in the fluorescent protein). Without this mutation the probe produces only a very small change in fluorescence in response to voltage deflections (∼ 1%). The large signal afforded by this mutation allows optical detection of action potentials and sub-threshold electrical events in single-trials in vitro and in vivo. However, it is unclear how this single mutation produces a probe with such a large modulation of its fluorescence output with changes in membrane potential. In this study, we identified which residues in super ecliptic pHluorin (vs eGFP) are critical for the ArcLight response, as a similarly constructed probe based on eGFP also exhibits large response amplitude if it carries these critical residues. We found that D147 is responsible for determining the pH sensitivity of the fluorescent protein used in these probes but by itself does not result in a voltage probe with a large signal. We also provide evidence that the voltage dependent signal of ArcLight is not simply sensing environmental pH changes. A two-photon polarization microscopy study showed that ArcLight's response to changes in membrane potential includes a reorientation of the super ecliptic pHluorin. We also explored different changes including modification of linker length, deletion of non-essential amino acids in the super ecliptic pHluorin, adding a farnesylation site, using tandem fluorescent proteins and other pH sensitive fluorescent proteins.

  7. 78 FR 24233 - Certain Dimmable Compact Fluorescent Lamps and Products Containing Same: Notice of Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Dimmable Compact Fluorescent Lamps and Products Containing Same: Notice of Institution of... importation of certain dimmable compact fluorescent lamps (``CFLs'') and products containing the same by...

  8. The Effect of Time on Bone Fluorescence: Implications for Using Alternate Light Sources to Search for Skeletal Remains.

    PubMed

    Swaraldahab, Mohamed A H; Christensen, Angi M

    2016-03-01

    Bones fluoresce when exposed to certain wavelengths of shortwave light, and this property can be useful in locating and sorting skeletal remains in forensic contexts. The proteins in bone collagen are largely responsible for its fluorescent properties, but these proteins degrade and denature over time. This study examined the fluorescence of bones from four temporal groups (recent, semi-recent, ancient, and historic) ranging from 0 to 1064 years before present. Specimens were photographed under 490 nm wavelength light, and fluorescence was quantified by converting intensity to a gray scale value based on the RGB color model using ImageJ(®) software. Significant (p < 0.05) differences were found in mean fluorescence between all four temporal groups, and a 0.324 coefficient of correlation indicates a significant (inverse) relationship between fluorescence and time. Bone fluorescence decreases with time, but some fluorescence is retained even in older samples. Fluorescence can therefore be reliably used in many modern skeletal remains searches.

  9. Online multispectral fluorescence lifetime values estimation and overlay onto tissue white-light video frames

    NASA Astrophysics Data System (ADS)

    Gorpas, Dimitris; Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Marcu, Laura

    2016-03-01

    Fluorescence lifetime imaging has been shown to be a robust technique for biochemical and functional characterization of tissues and to present great potential for intraoperative tissue diagnosis and guidance of surgical procedures. We report a technique for real-time mapping of fluorescence parameters (i.e. lifetime values) onto the location from where the fluorescence measurements were taken. This is achieved by merging a 450 nm aiming beam generated by a diode laser with the excitation light in a single delivery/collection fiber and by continuously imaging the region of interest with a color CMOS camera. The interrogated locations are then extracted from the acquired frames via color-based segmentation of the aiming beam. Assuming a Gaussian profile of the imaged aiming beam, the segmentation results are fitted to ellipses that are dynamically scaled at the full width of three automatically estimated thresholds (50%, 75%, 90%) of the Gaussian distribution's maximum value. This enables the dynamic augmentation of the white-light video frames with the corresponding fluorescence decay parameters. A fluorescence phantom and fresh tissue samples were used to evaluate this method with motorized and hand-held scanning measurements. At 640x512 pixels resolution the area of interest augmented with fluorescence decay parameters can be imaged at an average 34 frames per second. The developed method has the potential to become a valuable tool for real-time display of optical spectroscopy data during continuous scanning applications that subsequently can be used for tissue characterization and diagnosis.

  10. Highly linearly polarized white light emission from InGaN light-emitting diode with nanograting-integrated fluorescent ceramics

    NASA Astrophysics Data System (ADS)

    Chen, Linghua; Wang, Miao; Cao, Bing; Zhou, Shengming; Lin, Yu; Hu, Jingpei; Wang, Chinhua; Wang, Jianfeng; Sun, Qian; Xu, Ke

    2017-01-01

    We proposed and demonstrated a linearly polarized white light emission from an InGaN light-emitting diode with nanograting-integrated fluorescent ceramics. By incorporating a dielectric layer with low refractive index between multilayer nanogratings and a fluorescent ceramic, both high TM transmission (TMT) and high extinction ratio (ER) were effectively achieved across the entire range of white light. An ER higher than 20 dB and a TMT of 60% were obtained experimentally for a GaN/fluorescent-ceramic-integrated white LED with a multilayer grating of 150 nm period. The fluorescent-ceramic-integrated structure showed possibilities of implementing a polarized white LED with high performance.

  11. A model considering light reabsorption processes to correct in vivo chlorophyll fluorescence spectra in apples.

    PubMed

    Ramos, María E; Lagorio, María G

    2006-05-01

    Chlorophyll-a contained in the peel of Granny Smith apples emits fluorescence upon excitation with blue light. The observed emission, collected by an external detector and corrected by its spectral response, is still distorted by light reabsorption processes taking place in the fruit skin and differs appreciably from the true spectral distribution of fluorescence emerging from chlorophyll molecules in the biological tissue. Reabsorption processes particularly affect the ratio of fluorescence intensities at 680 nm and at 730 nm. A model to obtain the correct spectral distribution of the emission, from the experimental fluorescence recorded at a fluorometer detector and corrected for the detector spectral sensitivity, is developed in the present work. Measurements of the whole fruit reflectance, the peel transmittance and the flesh reflectance allow the calculation of the reabsorption-corrected spectra. The model is validated by comparing the corrected emission spectra with that obtained for a thin layer of apple-peel-chloroplasts, where no reabsorption takes place. It is recommended to correct distortions in emission spectra of intact fruits due to light reabsorption effects whenever a correlation between the physiological state of the fruit and its fluorescence spectra is investigated.

  12. 77 FR 11587 - Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-27

    ... COMMISSION Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Institution of... States after importation of certain dimmable compact fluorescent lamps and products containing same by... certain dimmable compact fluorescent lamps and products containing same that infringe one or more of...

  13. Decrease in fluorescence lifetime by glycation of collagen and its application in determining advanced glycation end-products in human dentin

    PubMed Central

    Fukushima, Shuichiro; Shimizu, Masato; Miura, Jiro; Matsuda, Yusuke; Kubo, Mizuho; Hashimoto, Mamoru; Aoki, Takuya; Takeshige, Fumio; Araki, Tsutomu

    2015-01-01

    Advanced Glycation End-products (AGEs) are produced by the Maillard reaction, which causes cross-linking of collagen and results in changes in the mechanical properties of collagen tissues. Several types of AGE fluoresce, and measurement of this fluorescence is effective for determining the presence of AGEs. Because fluorescence intensity by steady-state fluorometry is affected by sample surface condition and light source, we focused on fluorescence lifetime measurement (FLM). We found that fluorescence lifetime of collagen gel decreased with glycation progress. In vivo application of FLM for determination of AGEs was confirmed in human dentin. PMID:26137384

  14. Light induced fluorescence lidar developed and employed at the National Aviation Academy of Azerbaijan

    NASA Astrophysics Data System (ADS)

    Pashayev, Arif M.; Allahverdiyev, Kerim R.; Tagiyev, Bahadir G.; Sadikhov, Ilham A.

    2016-01-01

    A new laser induced fluorescence (LIF) KA-14 LIDAR (Light Identification Detection and Ranging) system for detecting of oil spills on the sea surface was developed and employed at the National Aviation Academy of Azerbaijan. Laser's parameters used in LIDAR are as follows: •laser CFR 200- type QUANTEL, λ = 355 nm, beam ∅ = 5.35 mm, f = 20 Hz, pulse duration and power τ = 7 ns and 60 mJ, respectively. The first results of measurements in the laboratory and the results of measurements at natural environment from distances up to 200 m revealed perspectives for using this LIDAR for detection of oil contaminations on sea as well as on earth surfaces (these measurements have been performed at Pirallahi Oil-Gas Production Company, Absheron peninsula, Baku, Azerbaijan). In the present work the results of emission spectra of crude oils taken from different regions of Absheron peninsula as well as the emission spectra of the oil spills on the surface of Caspian sea will be reported and discussed. These measurements open perspectives for using developed LIDAR for determination of place of oil-gas production company from which leakage takes place.

  15. Front-face fluorescence measurement of photosensitizers and lipid oxidation products during the photooxidation of butter.

    PubMed

    Veberg, A; Olsen, E; Nilsen, A N; Wold, J P

    2007-05-01

    This paper shows that fluorescence spectroscopy can measure both degradation of photosensitizers and formation of lipid oxidation products in light-exposed butter. The photosensitizers were already notably degraded after 4 h of light exposure, whereas fluorescent lipid oxidation products were detected after 5 d. The fluorescence measurements were highly correlated with sensory assessments of acidic and rancid flavor. Photosensitizer degradation is therefore a promising indirect indicator of the onset of lipid oxidation in butter. Sensory analysis and measurement of peroxide value showed that the level of lipid oxidation was significantly higher for butter stored in air compared with butter stored in nitrogen (N2). This might be explained by the formation of singlet oxygen from direct photooxidation and type II photosensitized oxidation. Addition of the singlet oxygen quencher beta-carotene reduced the rancid flavor intensity in the air and N2 packages from 9.0 to 4.9 and from 6.5 to 4.7, respectively. Results indicate that lipid oxidation in the butter stored in N2 was mainly caused by type I photosensitized reactions, because addition of beta-carotene had little effect on the rancid flavor intensity.

  16. Deep-tissue focal fluorescence imaging with digitally time-reversed ultrasound-encoded light

    PubMed Central

    Wang, Ying Min; Judkewitz, Benjamin; DiMarzio, Charles A.; Yang, Changhuei

    2012-01-01

    Fluorescence imaging is one of the most important research tools in biomedical sciences. However, scattering of light severely impedes imaging of thick biological samples beyond the ballistic regime. Here we directly show focusing and high-resolution fluorescence imaging deep inside biological tissues by digitally time-reversing ultrasound-tagged light with high optical gain (~5×105). We confirm the presence of a time-reversed optical focus along with a diffuse background—a corollary of partial phase conjugation—and develop an approach for dynamic background cancellation. To illustrate the potential of our method, we image complex fluorescent objects and tumour microtissues at an unprecedented depth of 2.5 mm in biological tissues at a lateral resolution of 36 μm×52 μm and an axial resolution of 657 μm. Our results set the stage for a range of deep-tissue imaging applications in biomedical research and medical diagnostics. PMID:22735456

  17. Live imaging of Tribolium castaneum embryonic development using light-sheet-based fluorescence microscopy.

    PubMed

    Strobl, Frederic; Schmitz, Alexander; Stelzer, Ernst H K

    2015-10-01

    Tribolium castaneum has become an important insect model organism for evolutionary developmental biology, genetics and biotechnology. However, few protocols for live fluorescence imaging of Tribolium have been reported, and little image data is available. Here we provide a protocol for recording the development of Tribolium embryos with light-sheet-based fluorescence microscopy. The protocol can be completed in 4-7 d and provides procedural details for: embryo collection, microscope configuration, embryo preparation and mounting, noninvasive live imaging for up to 120 h along multiple directions, retrieval of the live embryo once imaging is completed, and image data processing, for which exemplary data is provided. Stringent quality control criteria for developmental biology studies are also discussed. Light-sheet-based fluorescence microscopy complements existing toolkits used to study Tribolium development, can be adapted to other insect species, and requires no advanced imaging or sample preparation skills.

  18. Light scattering measurement of sodium polyacrylate products

    NASA Astrophysics Data System (ADS)

    Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie

    2015-03-01

    In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.

  19. Light-Enhanced Fluorescence of Multi-Level Cavitands Possessing Pyridazine Upper rim.

    PubMed

    Janosi, Tibor Zoltan; Makkai, Geza; Kegl, Timea; Matyus, Peter; Kollar, Laszlo; Erostyak, Janos

    2016-03-01

    Completely different fluorescence behaviour of cavitands based on a same calix[4]resorcinarene compound was observed. While the fluorescence intensity of the parent compound, tetramethyl-cavitand (1) slowly faded as a result of UV-light exposure, the emission of the three-level cavitand with pyridazine moieties at the upper rim (5a) was enhanced by the excitation in the UV-region. The structure of fluorescence emission (characterized by excitation-emission matrices) and the absorption of 5a remained unaltered. The analysis of fluorescence decay curves reveals the presence of two separated components assigned to two individual emitting species. The measured significant increase of the average lifetime and quantum yield is the consequence of the UV-light induced transition between the different states of 5a. These observations can be explained by the structural difference between 5a and 1. As a counterpart of the naked cavitand (1) with methyl substituents at the upper rim only, 5a has three additional moieties benzene, triazole and pyridazine levels. Computational studies proved the existence of two conformational isomers of 5a. Upon ultraviolet light excitation a "dark" to "light" conformational transition occurs between the two isomers. This hypothesis was confirmed by anisotropy decay measurements.

  20. The influence of visible light and inorganic pigments on fluorescence excitation emission spectra of egg-, casein- and collagen-based painting media

    NASA Astrophysics Data System (ADS)

    Nevin, A.; Anglos, D.; Cather, S.; Burnstock, A.

    2008-07-01

    Spectrofluorimetric analysis of proteinaceous binding media is particularly promising because proteins employed in paintings are often fluorescent and media from different sources have significantly different fluorescence spectral profiles. Protein-based binding media derived from eggs, milk and animal tissue have been used for painting and for conservation, but their analysis using non-destructive techniques is complicated by interferences with pigments, their degradation and their low concentration. Changes in the fluorescence excitation emission spectra of films of binding media following artificial ageing to an equivalent of 50 and 100 years of museum lighting include the reduction of bands ascribed to tyrosine, tryptophan and Maillard reaction products and an increase in fluorescent photodegradation. Fluorescence of naturally aged paint is dependent on the nature of the pigment present and, with egg-based media, in comparison with un-pigmented films, emissions ascribed to amino acids are more pronounced.

  1. Flexible fluorescent white organic light emitting diodes with ALD encapsulation

    NASA Astrophysics Data System (ADS)

    Tsai, Yu-Sheng; Chittawanij, Apisit; Juang, Fuh-Shyang; Lin, Pen-Chu; Hong, Lin-Ann; Tsai, Feng-Yu; Tseng, Ming-Hong; Wang, Ching-Chiun; Chen, Chien-Chih; Lin, Kung-Liang; Chen, Szu-Hao

    2015-08-01

    In this paper, the flexible white organic light-emitting diodes (WOLED) was fabricated on polyethylene naphthalate (PEN) with structure of ITO/EHI608 (75 nm)/HTG-1 (10 nm)/3% EB502:0.8% EY53 (5 nm)/3% EB502 (35 nm)/Alq3 (10 nm)/LiF (0.8 nm)/Al (150 nm) and was compared with glass substrate the same structure. It was seen that the performances of flexible and glass substrate are almost the same. The luminance, current efficiency, and CIE coordinates of flexible device is 6351 cd/m2, 12.7 cd/A, and (0.31, 0.38) at 50 mA/cm2, respectively. Then, an Al2O3/HfO2 film on polyethylene terephthalate (PET) was deposited using atomic layer deposition (ALD) as a thin film encapsulation layer have been described and compared, such as the characteristics of water permeability and lifetime of flexible WOLED. The results show that the PET/ALD film low value of about 0.04 g/m2d, and the PET film shows WVTR of about 3.8 g/m2/d. The lifetimes of PET/ALD and PET encapsulations are 840 min and 140 min, respectively. Simultaneous deposition of ALD film on PET film gave the lifetime of flexible WOLED is six times longer than device without ALD encapsulation.

  2. Self-assembled fluorescent hexaazatriphenylenes that act as a light-harvesting antenna.

    PubMed

    Ishi-i, Tsutomu; Murakami, Koh-ichi; Imai, Yusuke; Mataka, Shuntaro

    2006-07-21

    In this paper we report the self-assembling nature of fluorescent hexaazatriphenylenes (HATs) 6a-d with six alkyl/alkoxy-chain-containing biphenyl groups and their application to light-harvesting antennae. In a nonpolar solvent and the film state, the HAT derivatives form one-dimensional aggregates with an H-type parallel stacking mode, which were analyzed by 1H NMR, UV-vis, and steady-state and time-resolved fluorescence spectroscopy. When HAT derivative 7 with six perylenediimide moieties is incorporated into the one-dimensional aggregates, an efficient energy transfer takes place from the self-assembled HAT moiety as a light-harvesting antenna to the perylenediimide moiety as an energy acceptor. Further, when HAT derivative 8 with six triphenylamino moieties is newly added to the light-harvesting system, an intermolecular electron transfer occurs subsequently between the electron-accepting perylenediimide molecule and the electron-donating triphenylamino molecule.

  3. Compact fluorescence and white-light imaging system for intraoperative visualization of nerves

    NASA Astrophysics Data System (ADS)

    Gray, Dan; Kim, Evgenia; Cotero, Victoria; Staudinger, Paul; Yazdanfar, Siavash; tan Hehir, Cristina

    2012-02-01

    Fluorescence image guided surgery (FIGS) allows intraoperative visualization of critical structures, with applications spanning neurology, cardiology and oncology. An unmet clinical need is prevention of iatrogenic nerve damage, a major cause of post-surgical morbidity. Here we describe the advancement of FIGS imaging hardware, coupled with a custom nerve-labeling fluorophore (GE3082), to bring FIGS nerve imaging closer to clinical translation. The instrument is comprised of a 405nm laser and a white light LED source for excitation and illumination. A single 90 gram color CCD camera is coupled to a 10mm surgical laparoscope for image acquisition. Synchronization of the light source and camera allows for simultaneous visualization of reflected white light and fluorescence using only a single camera. The imaging hardware and contrast agent were evaluated in rats during in situ surgical procedures.

  4. A compact fluorescence and white light imaging system for intraoperative visualization of nerves

    NASA Astrophysics Data System (ADS)

    Gray, Dan; Kim, Evgenia; Cotero, Victoria; Staudinger, Paul; Yazdanfar, Siavash; Tan Hehir, Cristina

    2012-03-01

    Fluorescence image guided surgery (FIGS) allows intraoperative visualization of critical structures, with applications spanning neurology, cardiology and oncology. An unmet clinical need is prevention of iatrogenic nerve damage, a major cause of post-surgical morbidity. Here we describe the advancement of FIGS imaging hardware, coupled with a custom nerve-labeling fluorophore (GE3082), to bring FIGS nerve imaging closer to clinical translation. The instrument is comprised of a 405nm laser and a white light LED source for excitation and illumination. A single 90 gram color CCD camera is coupled to a 10mm surgical laparoscope for image acquisition. Synchronization of the light source and camera allows for simultaneous visualization of reflected white light and fluorescence using only a single camera. The imaging hardware and contrast agent were evaluated in rats during in situ surgical procedures.

  5. High-power, computer-controlled, light-emitting diode-based light sources for fluorescence imaging and image-guided surgery.

    PubMed

    Gioux, Sylvain; Kianzad, Vida; Ciocan, Razvan; Gupta, Sunil; Oketokoun, Rafiou; Frangioni, John V

    2009-01-01

    Optical imaging requires appropriate light sources. For image-guided surgery, in particular fluorescence-guided surgery, a high fluence rate, a long working distance, computer control, and precise control of wavelength are required. In this article, we describe the development of light-emitting diode (LED)-based light sources that meet these criteria. These light sources are enabled by a compact LED module that includes an integrated linear driver, heat dissipation technology, and real-time temperature monitoring. Measuring only 27 mm wide by 29 mm high and weighing only 14.7 g, each module provides up to 6,500 lx of white (400-650 nm) light and up to 157 mW of filtered fluorescence excitation light while maintaining an operating temperature < or = 50 degrees C. We also describe software that can be used to design multimodule light housings and an embedded processor that permits computer control and temperature monitoring. With these tools, we constructed a 76-module, sterilizable, three-wavelength surgical light source capable of providing up to 40,000 lx of white light, 4.0 mW/cm2 of 670 nm near-infrared (NIR) fluorescence excitation light, and 14.0 mW/cm2 of 760 nm NIR fluorescence excitation light over a 15 cm diameter field of view. Using this light source, we demonstrated NIR fluorescence-guided surgery in a large-animal model.

  6. Calibration of a wide-field frequency-domain fluorescence lifetime microscopy system using light emitting diodes as light sources.

    PubMed

    Elder, A D; Frank, J H; Swartling, J; Dai, X; Kaminski, C F

    2006-11-01

    High brightness light emitting diodes are an inexpensive and versatile light source for wide-field frequency-domain fluorescence lifetime imaging microscopy. In this paper a full calibration of an LED based fluorescence lifetime imaging microscopy system is presented for the first time. A radio-frequency generator was used for simultaneous modulation of light emitting diode (LED) intensity and the gain of an intensified charge coupled device (CCD) camera. A homodyne detection scheme was employed to measure the demodulation and phase shift of the emitted fluorescence, from which phase and modulation lifetimes were determined at each image pixel. The system was characterized both in terms of its sensitivity to measure short lifetimes (500 ps to 4 ns), and its capability to distinguish image features with small lifetime differences. Calibration measurements were performed in quenched solutions containing Rhodamine 6G dye and the results compared to several independent measurements performed with other measurement methodologies, including time correlated single photon counting, time gated detection, and acousto optical modulator (AOM) based modulation of excitation sources. Results are presented from measurements and simulations. The effects of limited signal-to-noise ratios, baseline drifts and calibration errors are discussed in detail. The implications of limited modulation bandwidth of high brightness, large area LED devices ( approximately 40 MHz for devices used here) are presented. The results show that phase lifetime measurements are robust down to sub ns levels, whereas modulation lifetimes are prone to errors even at large signal-to-noise ratios. Strategies for optimizing measurement fidelity are discussed. Application of the fluorescence lifetime imaging microscopy system is illustrated with examples from studies of molecular mixing in microfluidic devices and targeted drug delivery research.

  7. Fluorescent Carbon Quantum Dots as Single Light Converter for White LEDs

    NASA Astrophysics Data System (ADS)

    Feng, Xiaoting; Zhang, Feng; Wang, Yaling; Zhang, Yi; Yang, Yongzhen; Liu, Xuguang

    2016-06-01

    Synthesis of fluorescent carbon quantum dots (CQDs) as single light converter and their application in white light-emitting diodes (LEDs) are reported. CQDs were prepared by a one-step hydrothermal method using glucose and polyethylene glycol 200 as precursors. The structural and optical properties of the CQDs were investigated. The CQDs with uniform size of 4 nm possessed typical excitation-dependent emission wavelength and quantum yield of 3.5%. Under ultraviolet illumination, the CQDs in deionized water emitted bright blue fluorescence and produced broad visible-light emission with high red, green, and blue spectral component ratio of 63.5% (red-to-blue intensity to total intensity), suggesting great potential as single light converter for white LEDs. To demonstrate their potential, a white LED using CQDs as a single light converter was built. The device exhibited cool white light with corresponding color temperature of 5584 K and color coordinates of (0.32, 0.37), belonging to the white gamut. This research suggests that CQDs could be a promising candidate single light converter for white LEDs.

  8. Quasi-continuous combined scattered light and fluorescence measurements: a novel measurement technique for shaken microtiter plates.

    PubMed

    Samorski, M; Müller-Newen, G; Büchs, J

    2005-10-05

    A novel quasi-continuous on-line measuring technique for shaken microtiter plates is presented. Light scattering as well as intracellular and/or protein fluorescence (e.g. NADH, YFP) is measured during the shaking procedure, thus allowing a process monitoring of 96 different simultaneous cultures in a microtiter plate. In contrast to existing measurement techniques, the shaking process does not have to be stopped to take the measurements, thus avoiding the corresponding interruption of the cultures' oxygen supply and any unpredictable effects on the cultures. Experiments were conducted with E. coli in LB, TB, and MOPS minimal medium and V. natriegens in modified LB and TB media. Intensity curves of scattered light and NADH fluorescence were used to distinguish different lag phases, growth velocities, or inoculation densities. Data from this new method corresponded well to the off-line measured optical densities and to the oxygen transfer rates of cultures run in simultaneously conducted shake flask experiments at equivalent oxygen transfer capacities. With the aid of yellow fluorescence protein fused to interleukin-6 the optimal induction time of an expressing E. coli strain could be determined by on-line monitoring of product formation. Thus, this measuring technique enables the researcher to evaluate and to discriminate different cultures on a screening level and to improve screening conditions, process development and scale-up.

  9. Optical fiber light-emitting diode-induced fluorescence detection for capillary electrophoresis.

    PubMed

    Zhao, Shulin; Yuan, Hongyan; Xiao, Dan

    2006-02-01

    A highly sensitive optical fiber light-emitting diode (LED)-induced fluorescence detector for CE has been constructed and evaluated. In this detector, a violet or blue LED was used as the excitation source and an optical fiber with 40 microm OD was used to transmit the excitation light. The upper end of the fiber was inserted into the separation capillary and was situated right at the detection window. Fluorescence emission was collected by a 40 x microscope objective, focused on a spatial filter, and passed through a cutoff filter before reaching the photomultiplier tube. Output signals were recorded and processed with a computer using in-house written software. The present CE/fluorescence detector deploys a simple and inexpensive optical system that requires only an LED as the light source. Its utility was successfully demonstrated by the separation and determination of amino acids (AAs) labeled with naphthalene-2,3-dicarboxaldehyde (NDA) and FITC. Low detection limits were obtained ranging from 17 to 23 nM for NDA-tagged AAs and 8 to 12 nM for FITC-labeled AAs (S/N=3). By virtue of such valuable features as low cost, convenience, and miniaturization, the presented detection scheme was proven to be attractive for sensitive fluorescence detection in CE.

  10. Spectral composition of light and plant productivity.

    PubMed

    Tikhomirov, A A

    1996-01-01

    Among other problems the Institute of Biophysics is working on the development of physiological and fundamental aspects of intensive light cultivation of higher plants. These technologies can be used in life support systems for stationary space station such as a Lunar base, a planetary base or a large orbital station. The source of energy may be the Sun or a nuclear reactor. In certain conditions, such sources of energy allow the use of a very broad range of irradiance of plants, in particular in the light energy range up to 2-3 times the solar energy (up to 100-1200 W/m2 PAR). Our Institute was the first to show that under such a high irradiance, some plants (radish, wheat, for example) can actively photosynthesize and exhibit high productivity on a sowing area basis. These results were later confirmed in the laboratory of Prof. Salisbury (USA).

  11. Production of diesel fuel from light olefins

    SciTech Connect

    Tabak, S.A.; Krambeck, F.J.

    1986-03-01

    Mobile Research and Development Corporation has developed a catalytic process for converting light olefinic compounds to high quality gasoline and distillate. The process has been named Mobil Olefin to Gasoline and Distillate (MOGD) Process. Based on the Mobile zeolite catalyst ZSM-5, light olefins can be shape selectively oligomerized to higher molecular weight iso-olefins. In the gasoline boiling range, these olefins have a high octane number and for the diesel fuel range product a high cetane number and low pour point following hydrogenation. Through normally designed to process propylene or butylene, MOGD is applicable to a wide range of feed streams ranging from ethylene to 400/sup 0/F endpoint olefinic naphtha. The process has been tested using commercially-produced catalyst in refinery scale equipment.

  12. Far-red light photoactivatable near-infrared fluorescent proteins engineered from a bacterial phytochrome

    PubMed Central

    Piatkevich, Kiryl D.; Subach, Fedor V.; Verkhusha, Vladislav V.

    2013-01-01

    Ability to modulate fluorescence of optical probes can be used to enhance signal-to-noise ratio for imaging within highly autofluorescent environments, such as intact tissues and living organisms. Here we report two phytochrome-based photoactivatable near-infrared fluorescent proteins, named PAiRFP1 and PAiRFP2. PAiRFPs utilize heme-derived biliverdin, ubiquitous in mammalian tissues, as the chromophore. Initially weakly fluorescent PAiRFPs undergo photoconversion into a highly fluorescent state with excitation/emission at 690 nm/717 nm following a brief irradiation with far-red light. After photoactivation, PAiRFPs slowly revert back to initial state, enabling multiple photoactivation-relaxation cycles. Low-temperature optical spectroscopy reveals several intermediates involved in PAiRFP photocycles, which all differ from that of the bacteriophytochrome precursor. PAiRFPs can be photoactivated in a spatially selective manner in mouse tissues, and optical modulation of their fluorescence allows for substantial contrast enhancement, making PAiRFPs advantageous over permanently fluorescent probes for in vivo imaging conditions of high autofluorescence and low signal levels. PMID:23842578

  13. Image-guided surgery using near-infrared fluorescent light: from bench to bedside

    NASA Astrophysics Data System (ADS)

    Boogerd, Leonora S. F.; Handgraaf, Henricus J. M.; van de Velde, Cornelis J. H.; Vahrmeijer, Alexander L.

    2015-03-01

    Due to its relatively high tissue penetration, near-infrared (NIR; 700-900 nm) fluorescent light has the potential to visualize structures that need to be resected (e.g. tumors, lymph nodes) and structures that need to be spared (e.g. nerves, ureters, bile ducts). Until now, most clinical trials have focused on suboptimal, non-targeted dyes. Although successful, a new era in image-guided surgery has begun by the introduction of tumor-targeted agents. In this paper, we will describe how tumor-targeted NIR fluorescent imaging can be applied in a clinical setting.

  14. Fluorescence in scorpions under UV light; can chaerilids be a possible exception?

    PubMed

    Lourenço, Wilson R

    2012-12-01

    The fluorescence of scorpions in ultraviolet light, a well-known phenomenon, was discovered more than 60 years ago. Its possible function remains, however, a matter of discussion. Even during very recent studies, no conclusion has been reached. As suggested in these recent publications, the lack of or reduction of fluorescence could be a useful tool to explain the phenomenon. It is suggested here that, in at least some species of the family Chaerilidae Simon, this phenomenon is absent. This new discovery may initiate important comparative eco-physiological studies.

  15. 77 FR 4363 - Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Receipt of Complaint...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-27

    ... COMMISSION Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Receipt of Complaint... complaint entitled In Re Certain Dimmable Compact Fluorescent Lamps and Products Containing Same, DN 2873... within the United States after importation of certain dimmable compact fluorescent lamps and...

  16. Photocatalytic bactericidal action of fluorescent light in a titanium dioxide particle mixture: an in vitro study.

    PubMed

    Koseki, Hironobu; Shiraishi, Koutaro; Asahara, Tomohiko; Tsurumoto, Toshiyuki; Shindo, Hiroyuki; Baba, Koumei; Taoda, Hiroshi; Terasaki, Nao

    2009-06-01

    Traditional titanium dioxide (TiO(2)) has photocatalytic bactericidal properties only under ultraviolet (UV) irradiation, which restricts its use in clinical treatment regimens. In this study, we evaluated the photocatalytic bactericidal effects of an aqueous system of TiO(2) particles irradiated by fluorescent light (FL) on Staphylococcus aureus. A TiO(2) particle mixture containing 19 ppm (0.019 mg/mL) of TiO(2) was prepared. A bacterial solution of 1 x 10(5) CFU/mL was added one drop at a time to the TiO(2) mixture. The resulting product was then irradiated with FL. The bacterial survival rate decreased steadily in the TiO(2) mixture group, reaching 76.7% after 30 min of FL irradiation and 10.9% after 60 min. After 60 to 180 min, the bacterial survival ratio of the TiO(2) mixture group was significantly lower than that of the control group (P < 0.05). The present study indicates that treating the surfaces of surgical devices and the surgical field with a TiO(2) particle mixture can create a nearly sterile environment that can be maintained throughout surgery, even at low luminous intensities.

  17. 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.

  18. Enhanced Phycocyanin Production from Spirulina platensis using Light Emitting Diode

    NASA Astrophysics Data System (ADS)

    Bachchhav, Manisha Bhanudas; Kulkarni, Mohan Vinayak; Ingale, Arun G.

    2016-12-01

    This work investigates the performance of different cultivation conditions using Light Emitting Diode (LED) as a light source for the production of phycocyanin from Spirulina platensis. With LEDs under autotrophic conditions, red LED produced maximum amount of biomass (8.95 g/l). As compared to autotrophic cultivation with fluorescent lamp (control), cultivations using LEDs under autotrophic and mixotrophic mode significantly enhanced the phycocyanin content. For autotrophic conditions (with LED) phycocyanin content was in the range of 103-242 mg/g of dry biomass, whereas for mixotrophic conditions (0.1% glucose and LED) it was in the range of 254-380 mg/g of dry biomass. Spirulina cultivated with yellow LED under mixotrophic conditions had 5.4-fold more phycocyanin (380 mg/g of dry biomass) than control (70 mg/g of dry biomass). The present study demonstrates that the LEDs under mixotrophic conditions gave sixfold (2497 mg/l) higher yields of phycocyanin as compared to autotrophic condition under white light (415 mg/l).

  19. Associated strangeness production on light nuclei

    NASA Astrophysics Data System (ADS)

    Ernst, J.; Kingler, J.; Lippert, C.

    1991-04-01

    The study of light hyper-nuclei via associated strangeness production in (p, K+) reactions is discussed. Though the process is characterized by a very large momentum transfer the presence of short range correlations is expected to rise the cross section up to the order of nb/sr. Two approved proposals for high resolution studies of this reaction are discussed and respective detection limits are presented. The first is scheduled for October 1990 at the SPES4 spectrometer at the SATURNE acclerator (LNS Saclay). The second deals with the planned upgrading of the BIG KARL magnetic spectrograph at the cooled beam facility COSY being bulit at Forschungsanlage Jülich.

  20. High Power, Computer-Controlled, LED-Based Light Sources for Fluorescence Imaging and Image-Guided Surgery

    PubMed Central

    Gioux, Sylvain; Kianzad, Vida; Ciocan, Razvan; Gupta, Sunil; Oketokoun, Rafiou; Frangioni, John V.

    2009-01-01

    Optical imaging requires appropriate light sources. For image-guided surgery, and in particular fluorescence-guided surgery, high fluence rate, long working distance, computer control, and precise control of wavelength are required. In this study, we describe the development of light emitting diode (LED)-based light sources that meet these criteria. These light sources are enabled by a compact LED module that includes an integrated linear driver, heat-dissipation technology, and real-time temperature monitoring. Measuring only 27 mm W by 29 mm H, and weighing only 14.7 g, each module provides up to 6500 lx of white (400-650 nm) light and up to 157 mW of filtered fluorescence excitation light, while maintaining an operating temperature ≤ 50°C. We also describe software that can be used to design multi-module light housings, and an embedded processor that permits computer control and temperature monitoring. With these tools, we constructed a 76-module, sterilizable, 3-wavelength surgical light source capable of providing up to 40,000 lx of white light, 4.0 mW/cm2 of 670 nm near-infrared (NIR) fluorescence excitation light, and 14.0 mW/cm2 of 760 nm NIR fluorescence excitation light over a 15-cm diameter field-of-view. Using this light source, we demonstrate NIR fluorescence-guided surgery in a large animal model. PMID:19723473

  1. Light quality treatments enhance somatic seedling production in three southern pine species.

    PubMed

    Merkle, Scott A; Montello, Paul M; Xia, Xiuqin; Upchurch, Bruce L; Smith, Dale R

    2006-02-01

    Embryogenic cultures of loblolly pine (Pinus taeda L.), slash pine (Pinus elliottii Engelm.), longleaf pine (Pinus palustris Mill.) and slash pine x longleaf pine hybrids were initiated from immature seeds on an initiation medium containing 13.57 microM 2,4-dichlorophenoxyacetic acid and 2.22 microM benzylaminopurine. Embryogenic cultures proliferated and somatic embryos developed, matured and germinated following a modified protocol and media originally developed for radiata pine (Pinus radiata D. Don.) somatic seedling production. A discrete, light-sensitive pre-germination stage and a later germination (radicle emergence) stage were identified by the differential response of somatic embryos to light of different wavelengths. Different light quality treatments were applied during the pre-germination and germination steps, using cool white fluorescent bulbs or light-emitting diodes (LEDs), or both. In general, red wavelengths provided by LEDs during these steps resulted in higher frequencies of somatic embryo germination (up to 64%) and conversion (up to 50%), longer tap roots and more first-order lateral roots than the standard cool white fluorescent treatments or treatment with blue wavelengths from LEDs. In addition, exposure to red light allowed germination of somatic embryos of some clones that failed to produce germinants under fluorescent light. Germination and conversion were further enhanced by sequential application of cool white fluorescent light and red light, resulting in up to 100% germination and conversion in one experiment. Longleaf pine somatic embryos were especially responsive to the light quality treatments, resulting in the first report of somatic seedling production for this species.

  2. Life History Changes in Coral Fluorescence and the Effects of Light Intensity on Larval Physiology and Settlement in Seriatopora hystrix

    PubMed Central

    Roth, Melissa S.; Fan, Tung-Yung; Deheyn, Dimitri D.

    2013-01-01

    Fluorescence is common in both coral adult and larval stages, and is produced by fluorescent proteins that absorb higher energy light and emit lower energy light. This study investigated the changes of coral fluorescence in different life history stages and the effects of parental light environment on larval fluorescence, larval endosymbiotic dinoflagellate abundance, larval size and settlement in the brooding coral Seriatopora hystrix. Data showed that coral fluorescence changed during development from green in larvae to cyan in adult colonies. In larvae, two green fluorescent proteins (GFPs) co-occur where the peak emission of one GFP overlaps with the peak excitation of the second GFP allowing the potential for energy transfer. Coral larvae showed great variation in GFP fluorescence, dinoflagellate abundance, and size. There was no obvious relationship between green fluorescence intensity and dinoflagellate abundance, green fluorescence intensity and larval size, or dinoflagellate abundance and larval size. Larvae of parents from high and low light treatments showed similar green fluorescence intensity, yet small but significant differences in size, dinoflagellate abundance, and settlement. The large variation in larval physiology combined with subtle effects of parental environment on larval characteristics seem to indicate that even though adult corals produce larvae with a wide range of physiological capacities, these larvae can still show small preferences for settling in similar habitats as their parents. These data highlight the importance of environmental conditions at the onset of life history and parent colony effects on coral larvae. PMID:23544072

  3. Direct Evidence of Lack of Colocalisation of Fluorescently Labelled Gold Labels Used in Correlative Light Electron Microscopy

    PubMed Central

    Miles, Benjamin T.; Greenwood, Alexander B.; Benito-Alifonso, David; Tanner, Hugh; Galan, M. Carmen; Verkade, Paul; Gersen, Henkjan

    2017-01-01

    Fluorescently labelled nanoparticles are routinely used in Correlative Light Electron Microscopy (CLEM) to combine the capabilities of two separate microscope platforms: fluorescent light microscopy (LM) and electron microscopy (EM). The inherent assumption is that the fluorescent label observed under LM colocalises well with the electron dense nanoparticle observed in EM. Herein we show, by combining single molecule fluorescent imaging with optical detection of the scattering from single gold nanoparticles, that for a commercially produced sample of 10 nm gold nanoparticles tagged to Alexa-633 there is in fact no colocalisation between the fluorescent signatures of Alexa-633 and the scattering associated with the gold nanoparticle. This shows that the attached gold nanoparticle quenches the fluorescent signal by ~95%, or less likely that the complex has dissociated. In either scenario, the observed fluorescent signal in fact arises from a large population of untagged fluorophores; rendering these labels potentially ineffective and misleading to the field. PMID:28317888

  4. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    NASA Astrophysics Data System (ADS)

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-12-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p < 0.0001), suggesting a link to organic matter degradation. This inference was supported by the positive correlation (R2 > 0.95, p < 0.0001) between the net production of FDOM and the modeled degradation rates of particulate organic carbon sulfate reduction. The production of FDOM was more pronounced in a shallow shelf site S1 with a total net production ranging from 17.9 to 62.3 RU for different FDOM components above the SMTZ depth of ca. 4.1 mbsf, which presumably underwent more accumulation of particulate organic matter than the other three deeper sites. The sediments were generally found to be the sources of CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans.

  5. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    PubMed Central

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-01-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p < 0.0001), suggesting a link to organic matter degradation. This inference was supported by the positive correlation (R2 > 0.95, p < 0.0001) between the net production of FDOM and the modeled degradation rates of particulate organic carbon sulfate reduction. The production of FDOM was more pronounced in a shallow shelf site S1 with a total net production ranging from 17.9 to 62.3 RU for different FDOM components above the SMTZ depth of ca. 4.1 mbsf, which presumably underwent more accumulation of particulate organic matter than the other three deeper sites. The sediments were generally found to be the sources of CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans. PMID:27982085

  6. Quantified light-induced fluorescence, review of a diagnostic tool in prevention of oral disease

    NASA Astrophysics Data System (ADS)

    de Josselin de Jong, Elbert; Higham, Susan M.; Smith, Philip W.; van Daelen, Catherina J.; van der Veen, Monique H.

    2009-05-01

    Diagnostic methods for the use in preventive dentistry are being developed continuously. Few of these find their way into general practice. Although the general trend in medicine is to focus on disease prevention and early diagnostics, in dentistry this is still not the case. Nevertheless, in dental research some of these methods seem to be promising for near future use by the general dental professional. In this paper an overview is given of a method called quantitative light-induced fluorescence or (QLF) in which visible and harmless light excites the teeth in the patient's mouth to produce fluorescent images, which can be stored on disk and computer analyzed. White spots (early dental caries) are detected and quantified as well as bacterial metabolites on and in the teeth. An overview of research to validate the technique and modeling to further the understanding of the technique by Monte Carlo simulation is given and it is shown that the fluorescence phenomena can be described by the simulation model in a qualitative way. A model describing the visibility of red fluorescence from within the dental tissue is added, as this was still lacking in current literature. An overview is given of the clinical images made with the system and of the extensive research which has been done. The QLF™ technology has been shown to be of importance when used in clinical trials with respect to the testing of toothpastes and preventive treatments. It is expected that the QLF™ technology will soon find its way into the general dental practice.

  7. Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT

    NASA Astrophysics Data System (ADS)

    Hoyer, Patrick; de Medeiros, Gustavo; Balázs, Bálint; Norlin, Nils; Besir, Christina; Hanne, Janina; Kräusslich, Hans-Georg; Engelhardt, Johann; Sahl, Steffen J.; Hell, Stefan W.; Hufnagel, Lars

    2016-03-01

    We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5-12-fold compared with their conventional diffraction-limited LS analogs.

  8. Light-sheet fluorescence imaging to localize cardiac lineage and protein distribution

    PubMed Central

    Ding, Yichen; Lee, Juhyun; Ma, Jianguo; Sung, Kevin; Yokota, Tomohiro; Singh, Neha; Dooraghi, Mojdeh; Abiri, Parinaz; Wang, Yibin; Kulkarni, Rajan P.; Nakano, Atsushi; Nguyen, Thao P.; Fei, Peng; Hsiai, Tzung K.

    2017-01-01

    Light-sheet fluorescence microscopy (LSFM) serves to advance developmental research and regenerative medicine. Coupled with the paralleled advances in fluorescence-friendly tissue clearing technique, our cardiac LSFM enables dual-sided illumination to rapidly uncover the architecture of murine hearts over 10 by 10 by 10 mm3 in volume; thereby allowing for localizing progenitor differentiation to the cardiomyocyte lineage and AAV9-mediated expression of exogenous transmembrane potassium channels with high contrast and resolution. Without the steps of stitching image columns, pivoting the light-sheet and sectioning the heart mechanically, we establish a holistic strategy for 3-dimentional reconstruction of the “digital murine heart” to assess aberrant cardiac structures as well as the spatial distribution of the cardiac lineages in neonates and ion-channels in adults. PMID:28165052

  9. Light-sheet fluorescence imaging to localize cardiac lineage and protein distribution

    NASA Astrophysics Data System (ADS)

    Ding, Yichen; Lee, Juhyun; Ma, Jianguo; Sung, Kevin; Yokota, Tomohiro; Singh, Neha; Dooraghi, Mojdeh; Abiri, Parinaz; Wang, Yibin; Kulkarni, Rajan P.; Nakano, Atsushi; Nguyen, Thao P.; Fei, Peng; Hsiai, Tzung K.

    2017-02-01

    Light-sheet fluorescence microscopy (LSFM) serves to advance developmental research and regenerative medicine. Coupled with the paralleled advances in fluorescence-friendly tissue clearing technique, our cardiac LSFM enables dual-sided illumination to rapidly uncover the architecture of murine hearts over 10 by 10 by 10 mm3 in volume; thereby allowing for localizing progenitor differentiation to the cardiomyocyte lineage and AAV9-mediated expression of exogenous transmembrane potassium channels with high contrast and resolution. Without the steps of stitching image columns, pivoting the light-sheet and sectioning the heart mechanically, we establish a holistic strategy for 3-dimentional reconstruction of the “digital murine heart” to assess aberrant cardiac structures as well as the spatial distribution of the cardiac lineages in neonates and ion-channels in adults.

  10. Bright Multicolor Bandgap Fluorescent Carbon Quantum Dots for Electroluminescent Light-Emitting Diodes.

    PubMed

    Yuan, Fanglong; Wang, Zhibin; Li, Xiaohong; Li, Yunchao; Tan, Zhan'ao; Fan, Louzhen; Yang, Shihe

    2017-01-01

    Multicolor bandgap fluorescent carbon quantum dots (MCBF-CQDs) from blue to red with quantum yield up to 75% are synthesized using a solvothermal method. For the first time, monochrome electroluminescent light-emitting diodes (LEDs) with MCBF-CQDs directly as an active emission layer are fabricated. The maximum luminance of blue LEDs reaches 136 cd m(-2) , which is the best performance for CQD-based monochrome electroluminescent LEDs.

  11. Instrument for fluorescence sensing of circulating cells with diffuse light in mice in vivo

    NASA Astrophysics Data System (ADS)

    Zettergren, Eric; Vickers, Dwayne; Runnels, Judith; Murthy, Shashi K.; Lin, Charles P.; Niedre, Mark

    2012-03-01

    Accurate quantification of circulating cell populations in mice is important in many areas of preclinical biomedical research. Normally, this is done either by extraction and analysis of small blood samples or, more recently, by using microscopy-based in vivo fluorescence flow cytometry. We describe a new technological approach to this problem using detection of diffuse fluorescent light from relatively large blood vessels in vivo. The diffuse fluorescence flow cytometer (DFFC) uses a laser to illuminate a mouse limb and an array of optical fibers coupled to a high-sensitivity photomultiplier tube array operating in photon counting mode to detect weak fluorescence signals from cells. We first demonstrate that the DFFC instrument is capable of detecting fluorescent microspheres and Vybrant-DiD-labeled cells in a custom-made optical flow phantom with similar size, optical properties, linear flow rates, and autofluorescence as a mouse limb. We also present preliminary data demonstrating that the DFFC is capable of detecting circulating cells in nude mice in vivo. In principle, this device would allow interrogation of the whole blood volume of a mouse in minutes, with sensitivity improvement by several orders of magnitude compared to current approaches.

  12. High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence

    SciTech Connect

    Nishide, Jun-ichi; Hiraga, Yasuhide; Nakanotani, Hajime; Adachi, Chihaya

    2014-06-09

    White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).

  13. Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light.

    PubMed

    Wu, Qianyuan; Li, Chao; Wang, Wenlong; He, Tao; Hu, Hongying; Du, Ye; Wang, Ting

    2016-05-01

    Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter (DOM) was investigated in this study. Solar light significantly decreased the UV254 absorbance and fluorescence (FLU) intensity of reclaimed water. However, its effect on the dissolved organic carbon (DOC) value of reclaimed water was very limited. The decrease in the UV254 absorbance intensity and FLU excitation-emission matrix regional integration volume (FLU volume) of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV254 absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV254 absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV254 and FLU intensity were independent of light intensity. The peaks of the UV254 absorbance and FLU intensity with an apparent molecular weight (AMW) of 100Da to 2000Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change.

  14. Light irradiance and spectral distribution effects on cyanobacterial hydrogen production

    NASA Astrophysics Data System (ADS)

    Fatihah Salleh, Siti; Kamaruddin, Azlina; Hekarl Uzir, Mohamad; Rahman Mohamed, Abdul; Halim Shamsuddin, Abdul

    2016-03-01

    Light is an essential energy source for photosynthetic cyanobacteria. Changes in both light irradiance and spectral distribution will affect their photosynthetic productivity. Compared to the light irradiance, little investigations have been carried out on the effect of light spectra towards cyanobacterial hydrogen production. Hence, this work aims to investigate the effects of both light quantity and quality on biohydrogen productivity of heterocystous cyanobacterium, A.variabilis. Under white light condition, the highest hydrogen production rate of 31 µmol H2 mg chl a -1 h-1 was achieved at 70 µE m-2 s-1. When the experiment was repeated at the same light irradiance but different light spectra of blue, red and green, the accumulations of hydrogen were significantly lower than the white light except for blue light. As the light irradiance was increased to 350 µE m-2 s-1, the accumulated hydrogen under the blue light doubled that of the white light. Besides that, an unusual prolongation of the hydrogen production up to 120 h was observed. The results obtained suggest that blue light could be the most desirable light spectrum for cyanobacterial hydrogen production.

  15. Synthesis of polymeric fluorescent brightener based on coumarin and its performances on paper as light stabilizer, fluorescent brightener and surface sizing agent

    NASA Astrophysics Data System (ADS)

    Zhang, Guanghua; Zheng, Hua; Guo, Mingyuan; Du, Lun; Liu, Guojun; Wang, Peng

    2016-03-01

    In this work, a novel polymeric fluorescent brightener based on coumarin (PFBC) was synthesized, using three-step synthetic route, from 7-amino-4-methylcoumarin, coumarin monomer (FBC), Acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC). The structure of PFBC was characterized by FT-IR, 1HNMR and GPC. PFBC was applied to paper fiber as light stabilizer, fluorescent brightener and surface sizing agent and its performances were evaluated by measuring the UV-vis, fluorescence, thermal stability, the cationic degree, surface strength and smoothness of paper, the brightness degree of paper and the PC value of paper. Results showed that PFBC had better solubility in water than that of FBC, by measuring the optical properties. Through the surface sizing experiment and UV aging experiment, PFBC not only enhanced the surface strength and smoothness of paper as a surface sizing agent, but also had better effect on anti-UV aging than that of FBC as light stabilizer and fluorescent brightener.

  16. Filter-less fluorescence sensor with high separation ability achieved by the suppression of forward-scattered light in silicon

    NASA Astrophysics Data System (ADS)

    Choi, Yong Joon; Takahashi, Kazuhiro; Matsuda, Motoharu; Hizawa, Takeshi; Moriwaki, Yu; Dasai, Fumihiro; Kimura, Yasuyuki; Akita, Ippei; Iwata, Tatsuya; Ishida, Makoto; Sawada, Kazuaki

    2016-04-01

    The improvement of a filter-less fluorescence sensor, by suppressing forward scattering in silicon by surface planarization is presented. A fluorescence microscope has been widely used in biochemical fields. However, it is difficult to miniaturize because optical filters and other parts are necessary. We previously developed a filter-less fluorescence sensor. The separation ability of excitation light and fluorescence in the previous device was 550:1. It is necessary to improve the separation ability. This study focuses on the suppression of forward-scattered incident light in silicon, through the enhanced surface planarization of polysilicon, which is the gate electrode material. The separation ability of the filter-less fluorescence sensor was increased from 550:1 to 1250:1 by the suppression of forward-scattered light.

  17. Development of a High Output Fluorescent Light Module for the Commercial Plant Biotechnology Facility

    NASA Technical Reports Server (NTRS)

    Turner, Mark; Zhou, Wei-Jia; Doty, Laura (Technical Monitor)

    2000-01-01

    To maximize the use of available resources provided onboard the International Space Station, the development of an efficient lighting 1 system is critical to the overall performance of the CPBF. Not only is it important to efficiently generate photon energy, but thermal loads on the CPBF Temperature and Humidity Control System must be minimized. By utilizing optical coatings designed to produce highly diffuse reflectance in the visible wavelengths while minimizing reflectance in the infrared region, the design of the fluorescent light module for the CPBF is optimized for maximum photon flux, spatial uniformity and energy efficiency. Since the Fluorescent Light Module must be fully enclosed to meet (ISS) requirements for containment of particulates and toxic materials, heat removal from the lights presented some unique design challenges. By using the Express Rack moderate C, temperature-cooling loop, heat is rejected by means of a liquid/air coolant manifold. Heat transfer to the manifold is performed by conduction using copper fins, by forced air convection using miniature fans, and by radiation using optically selective coatings that absorb in the infrared wavelengths. Using this combination of heat transfer mechanisms builds in redundancy to prevent thermal build up and premature bulb failure.

  18. High-efficiency fluorescent organic light-emitting devices using sensitizing hosts with a small singlet-triplet exchange energy.

    PubMed

    Zhang, Dongdong; Duan, Lian; Li, Chen; Li, Yilang; Li, Haoyuan; Zhang, Deqiang; Qiu, Yong

    2014-08-06

    Materials with small singlet-triplet splits (ΔEST s) are introduced as sensitizing hosts to excite fluorescent dopants, breaking the trade-off between small ΔEST and high radiative decay rates. A highly efficient orange-fluorescent organic light-emitting diode (OLED) is prepared, showing a maximum external quantum efficiency of 12.2%.

  19. Generation of extended light-sheets for single and multi-photon fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Purnapatra, Subhajit B.; Pratim Mondal, Partha

    2013-07-01

    We theoretically propose and computationally demonstrate the generation of extended light-sheet for fluorescence microscopy. This is made possible by the introduction of a specially designed double-window spatial filter that allows the light to pass through the periphery and center of a cylindrical lens. When illuminated with a plane wave, the proposed filter results in an extended depth-of-focus along with side-lobes which are due to other interferences in the transverse focal plane. Computational studies show a maximum extension of light-sheet by 3.38 times for single photon excitation and 3.68 times for multiphoton excitation as compared to state-of-art single plane illumination microscopy system. This technique may facilitate the study of large biological specimens (such as Zebrafish embryo and tissue) with high spatial resolution and reduced photobleaching.

  20. Low Light CMOS Contact Imager with an Integrated Poly-Acrylic Emission Filter for Fluorescence Detection

    PubMed Central

    Dattner, Yonathan; Yadid-Pecht, Orly

    2010-01-01

    This study presents the fabrication of a low cost poly-acrylic acid (PAA) based emission filter integrated with a low light CMOS contact imager for fluorescence detection. The process involves the use of PAA as an adhesive for the emission filter. The poly-acrylic solution was chosen due its optical transparent properties, adhesive properties, miscibility with polar protic solvents and most importantly its bio-compatibility with a biological environment. The emission filter, also known as an absorption filter, involves dissolving an absorbing specimen in a polar protic solvent and mixing it with the PAA to uniformly bond the absorbing specimen and harden the filter. The PAA is optically transparent in solid form and therefore does not contribute to the absorbance of light in the visible spectrum. Many combinations of absorbing specimen and polar protic solvents can be derived, yielding different filter characteristics in different parts of the spectrum. We report a specific combination as a first example of implementation of our technology. The filter reported has excitation in the green spectrum and emission in the red spectrum, utilizing the increased quantum efficiency of the photo sensitive sensor array. The thickness of the filter (20 μm) was chosen by calculating the desired SNR using Beer-Lambert’s law for liquids, Quantum Yield of the fluorophore and the Quantum Efficiency of the sensor array. The filters promising characteristics make it suitable for low light fluorescence detection. The filter was integrated with a fully functional low noise, low light CMOS contact imager and experimental results using fluorescence polystyrene micro-spheres are presented. PMID:22399920

  1. Light induced fluorescence evaluation: A novel concept for caries diagnosis and excavation.

    PubMed

    Gugnani, Neeraj; Pandit, Ik; Srivastava, Nikhil; Gupta, Monika; Gugnani, Shalini

    2011-10-01

    In the era of minimal invasive dentistry, every effort should be directed to preserve the maximum tooth structure during cavity preparation. However, while making cavities, clinicians usually get indecisive at what point caries excavation should be stopped, so as to involve only the infected dentin. Apparent lack of valid clinical markers, difficulties with the use of caries detector dyes and chemo mechanical caries removal systems carve out a need for an improved system, which would be helpful to differentiate between the healthy and infected dentin during caries excavation. Light induced fluorescence evaluation is a novel concept implicated for caries detection and for making decisions while cavity preparation. This paper describes a few cases that explain the clinical applicability of this concept, using the SoproLife camera that works on this principle. Autofluorescence masking effect was found to be helpful for caries detection and the red fluorescence in the treatment mode was found helpful in deciding 'when to stop the excavation process.' Light induced fluorescence evaluation - Diagnosis - Treatment concept concept can be used as a guide for caries detection and excavation. It also facilitates decision making for stopping the caries excavation so as to involve infected dentin only.

  2. Light sheet fluorescence microscopy for in situ cell interaction analysis in mouse lymph nodes.

    PubMed

    Abe, Jun; Ozga, Aleksandra J; Swoger, Jim; Sharpe, James; Ripoll, Jorge; Stein, Jens V

    2016-04-01

    Reactive lymph nodes (LNs) are sites where pMHC-loaded dendritic cells (DCs) interact with rare cognate T cells, leading to their clonal expansion. While DC interactions with T cell subsets critically shape the ensuing immune response, surprisingly little is known on their spatial orchestration at physiologically T cell low precursor frequencies. Light sheet fluorescence microscopy and one of its implementations, selective plane illumination microscopy (SPIM), is a powerful method to obtain precise spatial information of entire organs of 0.5-10mm diameter, the size range of murine LNs. Yet, its usefulness for immunological research has thus far not been comprehensively explored. Here, we have tested and defined protocols that preserve fluorescent protein function during lymphoid tissue clearing required for SPIM. Reconstructions of SPIM-generated 3D data sets revealed that calibrated numbers of adoptively transferred T cells and DCs are successfully detected at a single cell level within optically cleared murine LNs. Finally, we define parameters to quantify specific interactions between antigen-specific T cells and pMHC-bearing DCs in murine LNs. In sum, our studies describe the successful application of light sheet fluorescence microscopy to immunologically relevant tissues.

  3. Quantitative Light Fluorescence (QLF) and Polarized White Light (PWL) assessments of dental fluorosis in an epidemiological setting

    PubMed Central

    2012-01-01

    Background To determine if a novel dual camera imaging system employing both polarized white light (PWL) and quantitative light induced fluorescence imaging (QLF) is appropriate for measuring enamel fluorosis in an epidemiological setting. The use of remote and objective scoring systems is of importance in fluorosis assessments due to the potential risk of examiner bias using clinical methods. Methods Subjects were recruited from a panel previously characterized for fluorosis and caries to ensure a range of fluorosis presentation. A total of 164 children, aged 11 years (±1.3) participated following consent. Each child was examined using the novel imaging system, a traditional digital SLR camera, and clinically using the Dean’s and Thylstrup and Fejerskov (TF) Indices on the upper central and lateral incisors. Polarized white light and SLR images were scored for both Dean’s and TF indices by raters and fluorescence images were automatically scored using software. Results Data from 164 children were available with a good distribution of fluorosis severity. The automated software analysis of QLF images demonstrated significant correlations with the clinical examinations for both Dean’s and TF index. Agreement (measured by weighted Kappa’s) between examiners scoring clinically, from polarized photographs and from SLR images ranged from 0.56 to 0.92. Conclusions The study suggests that the use of a digital imaging system to capture images for either automated software analysis, or remote assessment by raters is suitable for epidemiological work. The use of recorded images enables study archiving, assessment by multiple examiners, remote assessment and objectivity due to the blinding of subject status. PMID:22607363

  4. Lifetime of fluorescence from light-harvesting chlorophyll a/b proteins: excitation intensity dependence

    SciTech Connect

    Nordlund, T.M.; Knox, W.H.

    1981-10-01

    The fluorescence from a purified, aggregate form of the light-harvesting chlorophyll a/b protein has a lifetime of 1.2 +/- 0.5 ns at low excitation intensity, but the lifetime decreases significantly when the intensity of the 20-ps, 5300nm excitation pulse is increased above about 10/sup 16/ photons/cm/sup 2/. A solubilized, monomeric form of the protein, on the other hand, has a fluorescence lifetime of 3.1 +/- 0.3 ns independent of excitation intensity from 10/sup 14/-10/sup 18/ photons/cm/sup 2//pulse. We interpret the lifetime shortening in the aggregates and the lack of shortening in monomers in terms of exciton annihilation, facilitated in the aggregate by the larger population of interacting chlorophylls.

  5. Pulsed lasers versus continuous light sources in capillary electrophoresis and fluorescence detection studies: Photodegradation pathways and models.

    PubMed

    Boutonnet, Audrey; Morin, Arnaud; Petit, Pierre; Vicendo, Patricia; Poinsot, Véréna; Couderc, François

    2016-03-17

    Pulsed lasers are widely used in capillary electrophoresis (CE) studies to provide laser induced fluorescence (LIF) detection. Unfortunately pulsed lasers do not give linear calibration curves over a wide range of concentrations. While this does not prevent their use in CE/LIF studies, the non-linear behavior must be understood. Using 7-hydroxycoumarin (7-HC) (10-5000 nM), Tamra (10-5000 nM) and tryptophan (1-200 μM) as dyes, we observe that continuous lasers and LEDs result in linear calibration curves, while pulsed lasers give polynomial ones. The effect is seen with both visible light (530 nm) and with UV light (355 nm, 266 nm). In this work we point out the formation of byproducts induced by pulsed laser upon irradiation of 7-HC. Their separation by CE using two Zeta LIF detectors clearly shows that this process is related to the first laser detection. All of these photodegradation products can be identified by an ESI-/MS investigation and correspond to at least two 7HC dimers. By using the photodegradation model proposed by Heywood and Farnsworth (2010) and by taking into account the 7-HC results and the fact that in our system we do not have a constant concentration of fluorophore, it is possible to propose a new photochemical model of fluorescence in LIF detection. The model, like the experiment, shows that it is difficult to obtain linear quantitation curves with pulsed lasers while UV-LEDs used in continuous mode have this advantage. They are a good alternative to UV pulsed lasers. An application involving the separation and linear quantification of oligosaccharides labeled with 2-aminobezoic acid is presented using HILIC and LED (365 nm) induced fluorescence.

  6. Light quality and efficiency of consumer grade solid state lighting products

    NASA Astrophysics Data System (ADS)

    Dam-Hansen, Carsten; Corell, Dennis Dan; Thorseth, Anders; Poulsen, Peter Behrensdorff

    2013-03-01

    The rapid development in flux and efficiency of Light Emitting Diodes (LED) has resulted in a flooding of the lighting market with Solid State Lighting (SSL) products. Many traditional light sources can advantageously be replaced by SSL products. There are, however, large variations in the quality of these products, and some are not better than the ones they are supposed to replace. A lack of quality demands and standards makes it difficult for consumers to get an overview of the SSL products. Here the results of a two year study investigating SSL products on the Danish market are presented. Focus has been on SSL products for replacement of incandescent lamps and halogen spotlights. The warm white light and good color rendering properties of these traditional light sources are a must for lighting in Denmark and the Nordic countries. 266 SSL replacement lamps have been tested for efficiency and light quality with respect to correlated color temperature and color rendering properties. This shows a trade-off between high color rendering warm white light and energy efficiency. The lumen and color maintenance over time has been investigated and results for products running over 11000 h will be presented. A new internet based SSL product selection tool will be shown. Here the products can be compared on efficiency, light quality parameters, thus providing a better basis for the selection of SSL products for consumers.

  7. Resolving the depth of fluorescent light by structured illumination and shearing interferometry

    NASA Astrophysics Data System (ADS)

    Schindler, Johannes; Elmaklizi, Ahmed; Voit, Florian; Hohmann, Ansgar; Schau, Philipp; Brodhag, Nicole; Krauter, Philipp; Frenner, Karsten; Kienle, Alwin; Osten, Wolfgang

    2016-03-01

    A method for the depth-sensitive detection of fluorescent light is presented. It relies on a structured illumination restricting the excitation volume and on an interferometric detection of the wave front curvature. The illumination with two intersecting beams of a white-light laser separated in a Sagnac interferometer coupled to the microscope provides a coarse confinement in lateral and axial direction. The depth reconstruction is carried out by evaluating shearing interferograms produced with a Michelson interferometer. This setup can also be used with spatially and temporally incoherent light as emitted by fluorophores. A simulation workflow of the method was developed using a combination of a solution of Maxwell's equations with the Monte Carlo method. These simulations showed the principal feasibility of the method. The method is validated by measurements at reference samples with characterized material properties, locations and sizes of fluorescent regions. It is demonstrated that sufficient signal quality can be obtained for materials with scattering properties comparable to dental enamel while maintaining moderate illumination powers in the milliwatt range. The depth reconstruction is demonstrated for a range of distances and penetration depths of several hundred micrometers.

  8. Two-photon fluorescence and confocal reflected light imaging of thick tissue structures

    NASA Astrophysics Data System (ADS)

    Kim, Ki H.; So, Peter T. C.; Kochevar, Irene E.; Masters, Barry R.; Gratton, Enrico

    1998-04-01

    The technology of two-photon excitation has opened a window of opportunity for developing non-invasive medical diagnostic tools capable of monitoring thick tissue biochemical states. Using cellular endogenous chromophores, (beta) -nicotinamide- adenine dinucleotide phosphate [NAD(P)H], the cellular metabolic rates in living human skin were determined. Although important functional information can be obtained from the fluorescence spectroscopy of endogenous chromophores, these chromophores are rather poor contrast enhancing agent for mapping cellular morphology. First, most endogenous chromophores are confined to the cellular cytoplasm which prevents the visualization of other cellular organelles. Second, there is significant variability in the distribution and the quantum yield of endogenous chromophores which depends on tissue biochemistry but prevents consistent comparison of cellular morphology. On the other hand, the deep tissue cellular morphology has been imaged with excellent resolution using reflected light confocal microscopy. In reflected light microscopy, the image contrast originates from the index of refraction differences of the cellular structures. The organelle boundaries with significant index differences such as the plasma membrane and the nucleus envelope can be consistently visualized. A combination of morphological and functional information is required for a thorough tissue study. This presentation describes the development of a new microscope which is capable of simultaneously collecting both two-photon fluorescence and confocal reflected light signals. Promising biomedical applications include the non-invasive diagnosis of skin cancer and the study of wound healing.

  9. Localization of fluorescently labeled structures in frozen-hydrated samples using integrated light electron microscopy.

    PubMed

    Faas, F G A; Bárcena, M; Agronskaia, A V; Gerritsen, H C; Moscicka, K B; Diebolder, C A; van Driel, L F; Limpens, R W A L; Bos, E; Ravelli, R B G; Koning, R I; Koster, A J

    2013-03-01

    Correlative light and electron microscopy is an increasingly popular technique to study complex biological systems at various levels of resolution. Fluorescence microscopy can be employed to scan large areas to localize regions of interest which are then analyzed by electron microscopy to obtain morphological and structural information from a selected field of view at nm-scale resolution. Previously, an integrated approach to room temperature correlative microscopy was described. Combined use of light and electron microscopy within one instrument greatly simplifies sample handling, avoids cumbersome experimental overheads, simplifies navigation between the two modalities, and improves the success rate of image correlation. Here, an integrated approach for correlative microscopy under cryogenic conditions is presented. Its advantages over the room temperature approach include safeguarding the native hydrated state of the biological specimen, preservation of the fluorescence signal without risk of quenching due to heavy atom stains, and reduced photo bleaching. The potential of cryo integrated light and electron microscopy is demonstrated for the detection of viable bacteria, the study of in vitro polymerized microtubules, the localization of mitochondria in mouse embryonic fibroblasts, and for a search into virus-induced intracellular membrane modifications within mammalian cells.

  10. Spatial distribution of single-photon and two-photon fluorescence light in scattering media: Monte Carlo simulation.

    PubMed

    Gan, X; Gu, M

    2000-04-01

    Three-dimensional fluorescence spatial distributions under single-photon and two-photon excitation within a turbid medium are studied with Monte Carlo simulation. It is demonstrated that two-photon excitation has an advantage of producing much less fluorescence light outside the focal region compared with single-photon excitation. With the increase of the concentration of scattering particles in a turbid medium, the position of the maximum fluorescence intensity point shifts from the geometric focal region toward the medium surface. Further studies show that the optical sectioning property of two-photon fluorescence microscopy is degraded in thick turbid media or when the numerical aperture of an objective becomes low.

  11. Exposure to Fluorescent Light Triggers Down Regulation of Genes Involved with Mitotic Progression in Xiphophorus Skin

    PubMed Central

    Walter, Ronald B.; Walter, Dylan J.; Boswell, William T.; Caballero, Kaela L.; Boswell, Mikki; Lu, Yuan; Chang, Jordan; Savage, Markita G.

    2015-01-01

    We report RNA-Seq results from skin of X. maculatus Jp 163 B after exposure to various doses of “cool white” fluorescent light (FL). We show that FL exposure incites a genetic transcriptional response in skin nearly as great as observed for UVB exposure; however, the gene sets modulated due to exposure to the two light sources are quite different. Known light responsive genes involved in maintaining circadian cycling (e.g., clock, cry2a, cry1b, per1b, per2, per3, arntl1a, etc.) exhibited expected shifts in transcriptional expression upon FL exposure. Exposure to FL also resulted in down-regulated transcription of many genes involved with cell cycle progression (e.g., cdc20, cdc45, cdca7b, plk1, cdk1, ccnb-3, cdca7a, etc.) and chromosome segregation (e.g., cenpe, cenpf, cenpi, cenpk, cenpo, cenpp, and cenpu; cep70; knstrm, kntc, mcm2, mcm5; smc2, etc.). In addition, several DNA replication and recombination repair genes (e.g., pola1, pole, rec52, rad54l, rpa1, parpbp, etc.) exhibit reduced expression in FL exposed X. maculatus skin. Some genes down modulated by FL are known to be associated with DNA repair and human diseases (e.g., atm2, brip1, fanc1, fancl, xrcc4, etc.). The overall suppression of genes involved with mitotic progression in the skin of adult fish is consistent with entry into the light phase of the circadian cycle. Current efforts are aimed at determining specific wavelengths that may lead to differential expression among the many genes affected by fluorescent light exposure. PMID:26334372

  12. Light propagation from fluorescent probes in biological tissues by coupled time-dependent parabolic simplified spherical harmonics equations

    PubMed Central

    Domínguez, Jorge Bouza; Bérubé-Lauzière, Yves

    2011-01-01

    We introduce a system of coupled time-dependent parabolic simplified spherical harmonic equations to model the propagation of both excitation and fluorescence light in biological tissues. We resort to a finite element approach to obtain the time-dependent profile of the excitation and the fluorescence light fields in the medium. We present results for cases involving two geometries in three-dimensions: a homogeneous cylinder with an embedded fluorescent inclusion and a realistically-shaped rodent with an embedded inclusion alike an organ filled with a fluorescent probe. For the cylindrical geometry, we show the differences in the time-dependent fluorescence response for a point-like, a spherical, and a spherically Gaussian distributed fluorescent inclusion. From our results, we conclude that the model is able to describe the time-dependent excitation and fluorescent light transfer in small geometries with high absorption coefficients and in nondiffusive domains, as may be found in small animal diffuse optical tomography (DOT) and fluorescence DOT imaging. PMID:21483606

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

    NASA Astrophysics Data System (ADS)

    Groppo, D. P.; Caldas, L. V. E.

    2016-07-01

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

  14. Compact Fluorescent Lighting in America: Lessons Learned on the Way to Market

    SciTech Connect

    Sandahl, Linda J.; Gilbride, Theresa L.; Ledbetter, Marc R.; Steward, Heidi E.; Calwell, Chris

    2006-05-22

    This report describes the history of compact fluorescent lamps (CFLs) in America. CFLs were introduced in the 1970s; however, it has taken more than 20 years for them to gain widespread recognition in the U.S. residential lighting market. This report reviews the development of CFLs, efforts to increase market acceptance of them, and barriers to that acceptance. Lessons to be learned from this study of CFLs are identified in hopes of assisting future market introduction efforts for other promising energy-efficient technologies. This report was prepared by the Pacific Northwest National Laboratory for the U.S. Department of Energy’s Office of Building Technologies, Emerging Technologies Program.

  15. Development and application of fluorescent, green light-activatable caged compound

    NASA Astrophysics Data System (ADS)

    Umeda, Nobuhiro; Urano, Yasuteru; Nagano, Tetsuo

    2011-03-01

    Caged compound is one of the most powerful tools for spatiotemporal control of biomolecules in cells, which can be activated by irradiation of light. However, ultra violet light, which is required for activation of caged compounds, can damage cells and has poor permeability into tissues. In addition, invisibility of caged compounds makes it difficult to tell distribution of released small molecules. At the conference, we will describe the development of novel caging group and new caged compounds which are fluorescently visible and efficiently activatable with green light. We have found that boron dipyrromethene (BODIPY), known as a widely used fluorophore, is a potential caging group for phenol, carboxyl acid and amine, which can be photolized with irradiation of green light at around 500 nm wavelength. Based on the novel photo-reaction of 4-phenoxy BODIPY derivatives, we have developed caged histamine and applied it to HeLa cells. Photo-irradiation to cells in the presence of caged histamine induced transient increase of calcium ion in cytosol, which was specifically inhibited with pyrilamine, a H1 blocker. Also, we showed that BODIPY-caged compound can be utilized in vivo with tissue-permeable 500 nm green light.

  16. UV-A emission from fluorescent energy-saving light bulbs alters local retinoic acid homeostasis.

    PubMed

    Hellmann-Regen, Julian; Heuser, Isabella; Regen, Francesca

    2013-12-01

    Worldwide bans on incandescent light bulbs (ILBs) drive the use of compact fluorescent light (CFL) bulbs, which emit ultraviolet (UV) radiation. Potential health issues of these light sources have already been discussed, including speculation about the putative biological effects on light exposed tissues, yet the underlying mechanisms remain unclear. We hypothesized photoisomerization of all-trans retinoic acid (at-RA), a highly light sensitive morphogen, into biologically less active isomers, as a mechanism mediating biological effects of CFLs. Local at-RA is anti-carcinogenic, entrains molecular rhythms and is crucial for skin homeostasis. Therefore, we quantified the impact of CFL irradiation on extra- and intracellular levels of RA isomers using an epidermal cell culture model. Moreover, a biologically relevant impact of CFL irradiation was assessed using highly at-RA-sensitive human neuroblastoma cells. Dose-dependent conversion of extra- and intracellular at-RA into the biologically less active 13-cis-isomer was significantly higher in CFL vs. ILB exposure and completely preventable by employing a UV-filter. Moreover, pre-irradiation of culture media by CFL attenuated at-RA-specific effects on cell viability in human at-RA-sensitive cells in a dose-dependent manner. These findings point towards a biological relevance of CFL-induced at-RA decomposition, providing a mechanism for CFL-mediated effects on environmental health.

  17. Light stress effect and by nitrogen deficiency in plants of Petiveria alliacea measured with two-chlorophyll-fluorescence technique

    NASA Astrophysics Data System (ADS)

    Zuluaga, H.; Oviedo, A.; Solarte, Efrain; Pena, E. J.

    2004-10-01

    The chlorophyll fluorescence was studied in Petiveria alliacea plants exposed to different nitrogen concentrations and light radiation, the response was measured by two different forms; (1) measuring the photosynthetic efficiency with a pulse amplitude modulated fluorometro (PAM) emitted by a 650 nm diode and (2) measuring the fluorescence spectra caused by high power 452 nm diode with a SD2000 spectrometer. It was found out that the photosynthetic efficiency decreased in the plants exposed to high radiance and low nitrogen. Two chlorophyll fluorescence peaks were observed on 684 nm and 739 nm, the intensities in this wavelengths are inversely related with the light radiance. The correlation between the FIR and photosynthetic efficiency was very strong (r2 = -0.809, p <<0.01) this let us conclude that the fluorescence spectral analysis induced by the diode (excitation at 452 nm) is an efficient technique to detect stress by high light intensity and nitrogen in P. Alliacea plants.

  18. Fluorescent light activates the immunomodulator cis-urocanic acid in vitro: implications for patients with systemic lupus erythematosus.

    PubMed Central

    McGrath, H; Bell, J M; Haycock, J W

    1994-01-01

    OBJECTIVE--Erythemagenic (295-305 nm) ultraviolet-B (UVB) radiation is toxic to patients with systemic lupus erythematosus (SLE). Cool white fluorescent lamp emissions produce a similar toxicity even though the UVB radiation emitted is primarily at the relatively non-erythemagenic wavelength of 313 nm. The purpose of this study was to determine if fluorescent light, presumably acting predominantly along the 313 nm wavelength, exhibits photochemical activity sufficient to account for toxicity. METHODS--The photochemical activity of fluorescent light was assessed by testing its capacity to activate urocanic acid, a plentiful and potent epidermal immunological mediator normally activated by polychromatic UVB radiation but activated maximally at 313 nm. Irradiation-induced isomerisation of trans-urocanic to cis-urocanic acid was quantitated by UV spectroscopy after separation of the isomers by high performance liquid chromatography. RESULTS--Fluorescent light irradiation of solutions containing the photoreceptor trans-urocanic acid produced a cumulative conversion of trans-to-cis-urocanic acid. This photochemical activity was compared with that of erythemagenic sunlamps, high in polychromatic UVB emissions. When normalised for UVB irradiance, the accumulation of cis-urocanic acid produced by both light sources was essentially equivalent. Conventional acrylic diffusers that absorb UVB emissions eliminated the fluorescent light-induced reaction. CONCLUSION--The results indicate that radiation from fluorescent lamps possesses substantial photoimmunological capability, sufficient to activate a potent, potentially dangerous, disease-modifying, immunomodulatory pathway and that poorly erythemagenic, primarily monochromatic UVB photons are responsible. PMID:8037497

  19. Developing a genetically encoded green fluorescent protein mutant for sensitive light-up fluorescent sensing and cellular imaging of Hg(II).

    PubMed

    Jiang, Tao; Guo, Daiping; Wang, Qian; Wu, Xin; Li, Zhao; Zheng, Zhenhua; Yin, Boyuan; Xia, Lin; Tang, Jixian; Luo, Wenxin; Xia, Ningshao; Jiang, Yunbao

    2015-05-30

    Hg(II) is well-known for quenching fluorescence in a distance dependent manner. Nevertheless, when we exposed the fluorophore of a green fluorescent protein (GFP) toward Hg(II), through H148C mutation, the GFP fluorescence could be "lighted up" by Hg(II) down to sub-nM level. The detection linear range is 0.5-3.0 nM for protein solutions at 8.0 nM. The GFPH148C protein displayed a promising selectivity toward Hg(II) and also the cellular imaging capacity. Spectra measurements suggested that the ground-state redistribution of protein contributed to the fluorescence enhancement, which was found not limited to Hg(II), and thus presented an opening for building a pool of GFP-based chemosensors toward other heavy metal ions.

  20. Far-red light activatable, multifunctional prodrug for fluorescence optical imaging and combinational treatment.

    PubMed

    Bio, Moses; Rajaputra, Pallavi; Nkepang, Gregory; You, Youngjae

    2014-04-24

    We recently developed "photo-unclick chemistry", a novel chemical tool involving the cleavage of aminoacrylate by singlet oxygen, and demonstrated its application to visible light-activatable prodrugs. In this study, we prepared an advanced multifunctional prodrug, Pc-(L-CA4)2, composed of the fluorescent photosensitizer phthalocyanine (Pc), an SO-labile aminoacrylate linker (L), and a cytotoxic drug combretastatin A-4 (CA4). Pc-(L-CA4)2 had reduced dark toxicity compared with CA4. However, once illuminated, it showed improved toxicity similar to CA4 and displayed bystander effects in vitro. We monitored the time-dependent distribution of Pc-(L-CA4)2 using optical imaging with live mice. We also effectively ablated tumors by the illumination with far-red light to the mice, presumably through the combined effects of photodynamic therapy (PDT) and released chemotherapy drug, without any sign of acute systemic toxicity.

  1. Effects of fluorescent lighting on in vitro micropropagation of Lemna minor

    NASA Astrophysics Data System (ADS)

    Somsri, Kollawat; Pinyopich, Pataradawn; Mohammed, Waleed S.

    2010-05-01

    The vegetative in vitro propagation of Lemna minor stain SING-4 exposed to two different types of fluorescent light sources, Philips TLD 36W/54 and Toshiba FL40T8BRF/36, was studied. The liquid culture medium contained 4.43gl-1 phytohormone-free full-strength Murashige & Skoog (MS) basal medium with vitamins, 30gl-1 sucrose, and 1gl-1 MES. The results showed that both plant cultures had undergone normal asexual reproduction with an exponential increase trend. Cultures exposed to Toshiba FL40T8BRF/36 reproduced at a slightly faster rate while expressing significantly greener foliage (leaf color chart shade No.8), which indicates the presence of more chlorophyll, than cultures exposed to Philips TLD 36W/54 (leaf color chart shade No.4). The data obtained from our experiment reveals that light emitted from Toshiba FL40T8BRF/36 produces healthier and higher quality cultures.

  2. Purely Organic Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes.

    PubMed

    Wong, Michael Y; Zysman-Colman, Eli

    2017-03-03

    The design of thermally activated delayed fluorescence (TADF) materials both as emitters and as hosts is an exploding area of research. The replacement of phosphorescent metal complexes with inexpensive organic compounds in electroluminescent (EL) devices that demonstrate comparable performance metrics is paradigm shifting, as these new materials offer the possibility of developing low-cost lighting and displays. Here, a comprehensive review of TADF materials is presented, with a focus on linking their optoelectronic behavior with the performance of the organic light-emitting diode (OLED) and related EL devices. TADF emitters are cross-compared within specific color ranges, with a focus on blue, green-yellow, orange-red, and white OLEDs. Organic small-molecule, dendrimer, polymer, and exciplex emitters are all discussed within this review, as is their use as host materials. Correlations are provided between the structure of the TADF materials and their optoelectronic properties. The success of TADF materials has ushered in the next generation of OLEDs.

  3. Far-Red Light Activatable, Multifunctional Prodrug for Fluorescence Optical Imaging and Combinational Treatment

    PubMed Central

    2015-01-01

    We recently developed “photo-unclick chemistry”, a novel chemical tool involving the cleavage of aminoacrylate by singlet oxygen, and demonstrated its application to visible light-activatable prodrugs. In this study, we prepared an advanced multifunctional prodrug, Pc-(L-CA4)2, composed of the fluorescent photosensitizer phthalocyanine (Pc), an SO-labile aminoacrylate linker (L), and a cytotoxic drug combretastatin A-4 (CA4). Pc-(L-CA4)2 had reduced dark toxicity compared with CA4. However, once illuminated, it showed improved toxicity similar to CA4 and displayed bystander effects in vitro. We monitored the time-dependent distribution of Pc-(L-CA4)2 using optical imaging with live mice. We also effectively ablated tumors by the illumination with far-red light to the mice, presumably through the combined effects of photodynamic therapy (PDT) and released chemotherapy drug, without any sign of acute systemic toxicity. PMID:24694092

  4. Fluorescent chlorophyll catabolites in bananas light up blue halos of cell death.

    PubMed

    Moser, Simone; Müller, Thomas; Holzinger, Andreas; Lütz, Cornelius; Jockusch, Steffen; Turro, Nicholas J; Kräutler, Bernhard

    2009-09-15

    Breakdown of chlorophyll is a major contributor to the diagnostic color changes in fall leaves, and in ripening apples and pears, where it commonly provides colorless, nonfluorescent tetrapyrroles. In contrast, in ripening bananas (Musa acuminata) chlorophylls fade to give unique fluorescent catabolites (FCCs), causing yellow bananas to glow blue, when observed under UV light. Here, we demonstrate the capacity of the blue fluorescent chlorophyll catabolites to signal symptoms of programmed cell death in a plant. We report on studies of bright blue luminescent rings on the peel of very ripe bananas, which arise as halos around necrotic areas in 'senescence associated' dark spots. These dark spots appear naturally on the peel of ripe bananas and occur in the vicinity of stomata. Wavelength, space, and time resolved fluorescence measurements allowed the luminescent areas to be monitored on whole bananas. Our studies revealed an accumulation of FCCs in luminescent rings, within senescing cells undergoing the transition to dead tissue, as was observable by morphological textural cellular changes. FCCs typically are short lived intermediates of chlorophyll breakdown. In some plants, FCCs are uniquely persistent, as is seen in bananas, and can thus be used as luminescent in vivo markers in tissue undergoing senescence. While FCCs still remain to be tested for their own hypothetical physiological role in plants, they may help fill the demand for specific endogenous molecular reporters in noninvasive assays of plant senescence. Thus, they allow for in vivo studies, which provide insights into critical stages preceding cell death.

  5. Retrieving the axial position of fluorescent light emitting spots by shearing interferometry

    NASA Astrophysics Data System (ADS)

    Schindler, Johannes; Schau, Philipp; Brodhag, Nicole; Frenner, Karsten; Osten, Wolfgang

    2016-12-01

    A method for the depth-resolved detection of fluorescent radiation based on imaging of an interference pattern of two intersecting beams and shearing interferometry is presented. The illumination setup provides the local addressing of the excitation of fluorescence and a coarse confinement of the excitation volume in axial and lateral directions. The reconstruction of the depth relies on the measurement of the phase of the fluorescent wave fronts. Their curvature is directly related to the distance of a source to the focus of the imaging system. Access to the phase information is enabled by a lateral shearing interferometer based on a Michelson setup. This allows the evaluation of interference signals even for spatially and temporally incoherent light such as emitted by fluorophors. An analytical signal model is presented and the relations for obtaining the depth information are derived. Measurements of reference samples with different concentrations and spatial distributions of fluorophors and scatterers prove the experimental feasibility of the method. In a setup optimized for flexibility and operating in the visible range, sufficiently large interference signals are recorded for scatterers placed in depths in the range of hundred micrometers below the surface in a material with scattering properties comparable to dental enamel.

  6. Lighting Up Clostridium Difficile: Reporting Gene Expression Using Fluorescent Lov Domains

    PubMed Central

    Buckley, Anthony M.; Jukes, Caitlin; Candlish, Denise; Irvine, June J.; Spencer, Janice; Fagan, Robert P.; Roe, Andrew J.; Christie, John M.; Fairweather, Neil F.; Douce, Gillian R.

    2016-01-01

    The uses of fluorescent reporters derived from green fluorescent protein have proved invaluable for the visualisation of biological processes in bacteria grown under aerobic conditions. However, their requirement for oxygen has limited their application in obligate anaerobes such as Clostridium difficile. Fluorescent proteins derived from Light, Oxygen or Voltage sensing (LOV) domains have been shown to bridge this limitation, but their utility as translational fusions to monitor protein expression and localisation in a strict anaerobic bacterium has not been reported. Here we demonstrate the utility of phiLOV in three species of Clostridium and its application as a marker of real-time protein translation and dynamics through genetic fusion with the cell division protein, FtsZ. Time lapse microscopy of dividing cells suggests that Z ring assembly arises through the extension of the FtsZ arc starting from one point on the circumference. Furthermore, through incorporation of phiLOV into the flagella subunit, FliC, we show the potential of bacterial LOV-based fusion proteins to be successfully exported to the extracellular environment. PMID:26996606

  7. Fluorescent chlorophyll catabolites in bananas light up blue halos of cell death

    PubMed Central

    Moser, Simone; Müller, Thomas; Holzinger, Andreas; Lütz, Cornelius; Jockusch, Steffen; Turro, Nicholas J.; Kräutler, Bernhard

    2009-01-01

    Breakdown of chlorophyll is a major contributor to the diagnostic color changes in fall leaves, and in ripening apples and pears, where it commonly provides colorless, nonfluorescent tetrapyrroles. In contrast, in ripening bananas (Musa acuminata) chlorophylls fade to give unique fluorescent catabolites (FCCs), causing yellow bananas to glow blue, when observed under UV light. Here, we demonstrate the capacity of the blue fluorescent chlorophyll catabolites to signal symptoms of programmed cell death in a plant. We report on studies of bright blue luminescent rings on the peel of very ripe bananas, which arise as halos around necrotic areas in ‘senescence associated’ dark spots. These dark spots appear naturally on the peel of ripe bananas and occur in the vicinity of stomata. Wavelength, space, and time resolved fluorescence measurements allowed the luminescent areas to be monitored on whole bananas. Our studies revealed an accumulation of FCCs in luminescent rings, within senescing cells undergoing the transition to dead tissue, as was observable by morphological textural cellular changes. FCCs typically are short lived intermediates of chlorophyll breakdown. In some plants, FCCs are uniquely persistent, as is seen in bananas, and can thus be used as luminescent in vivo markers in tissue undergoing senescence. While FCCs still remain to be tested for their own hypothetical physiological role in plants, they may help fill the demand for specific endogenous molecular reporters in noninvasive assays of plant senescence. Thus, they allow for in vivo studies, which provide insights into critical stages preceding cell death. PMID:19805212

  8. Use of quantitative light-induced fluorescence to monitor tooth whitening

    NASA Astrophysics Data System (ADS)

    Amaechi, Bennett T.; Higham, Susan M.

    2001-04-01

    The changing of tooth shade by whitening agents occurs gradually. Apart from being subjective and affected by the conditions of the surroundings, visual observation cannot detect a very slight change in tooth color. An electronic method, which can communicate the color change quantitatively, would be more reliable. Quantitative Light- induced Fluorescence (QLF) was developed to detect and assess dental caries based on the phenomenon of change of autofluorescence of a tooth by demineralization. However, stains on the tooth surface exhibit the same phenomenon, and therefore QLF can be used to measure the percentage fluorescence change of stained enamel with respect to surrounding unstained enamel. The present study described a technique of assessing the effect of a tooth-whitening agent using QLF. This was demonstrated in two experiments in which either wholly or partially stained teeth were whitened by intermittent immersion in sodium hypochlorite. Following each immersion, the integrated fluorescence change due to the stain was quantified using QLF. In either situation, the value of (Delta) Q decreased linearly as the tooth regained its natural shade. It was concluded that gradual changing of the shade of discolored teeth by a whitening agent could be quantified using QLF.

  9. Nuclear export of single native mRNA molecules observed by light sheet fluorescence microscopy.

    PubMed

    Siebrasse, Jan Peter; Kaminski, Tim; Kubitscheck, Ulrich

    2012-06-12

    Nuclear export of mRNA is a key transport process in eukaryotic cells. To investigate it, we labeled native mRNP particles in living Chironomus tentans salivary gland cells with fluorescent hrp36, the hnRNP A1 homolog, and the nuclear envelope by fluorescent NTF2. Using light sheet microscopy, we traced single native mRNA particles across the nuclear envelope. The particles were observed to often probe nuclear pore complexes (NPC) at their nuclear face, and in only 25% of the cases yielded actual export. The complete export process took between 65 ms up to several seconds. A rate-limiting step was observed, which could be assigned to the nuclear basket of the pore and might correspond to a repositioning and unfolding of mRNPs before the actual translocation. Analysis of single fluorescent Dbp5 molecules, the RNA helicase essential for mRNA export, revealed that Dbp5 most often approached the cytoplasmic face of the NPC, and exhibited a binding duration of approximately 55 ms. Our results have allowed a refinement of the current models for mRNA export.

  10. In vitro quantitative light-induced fluorescence to measure changes in enamel mineralization.

    PubMed

    Gmür, Rudolf; Giertsen, Elin; van der Veen, Monique H; de Josselin de Jong, Elbert; ten Cate, Jacob M; Guggenheim, Bernhard

    2006-09-01

    A sensitive, quantitative method for investigating changes in enamel mineralization of specimens subjected to in vitro or in situ experimentation is presented. The fluorescence-detecting instrument integrates a Xenon arc light source and an object positioning stage, which makes it particularly suitable for the nondestructive assessment of demineralized or remineralized enamel. We demonstrate the ability of in vitro quantitative light-induced fluorescence (QLF) to quantify changes in mineralization of bovine enamel discs that had been exposed in vitro to a demineralizing gel (n=36) or biofilm-mediated demineralization challenges (n=10), or were carried in situ by three volunteers during a 10-day experiment (n=12). Further experiments show the technique's value for monitoring the extent of remineralization in 36 specimens exposed in vitro to oral multispecies biofilms and document the repeatability of in vitro QLF measurements (n=10) under standardized assay conditions. The validity of the method is illustrated by comparison with transversal microradiography (TMR), the invasive current gold standard for assessing experimental changes in enamel mineralization. Ten discs with 22 measurement areas for comparison demonstrated a positive correlation between TMR and QLF (r=0.82). Filling a technological gap, this QLF system is a promising tool to assay in vitro nondestructively localized changes in mineralization of enamel specimens.

  11. Compact fluorescent lighting in Wisconsin: elevated atmospheric emission and landfill deposition post-EISA implementation.

    PubMed

    Arendt, John D; Katers, John F

    2013-07-01

    The majority of states in the USA, including Wisconsin, have been affected by elevated air, soil and waterborne mercury levels. Health risks associated with mercury increase from the consumption of larger fish species, such as Walleye or Pike, which bio-accumulate mercury in muscle tissue. Federal legislation with the 2011 Mercury and Air Toxics Standards and the Wisconsin legislation on mercury, 2009 Wisconsin Act 44, continue to aim at lowering allowable levels of mercury emissions. Meanwhile, mercury-containing compact fluorescent lights (CFL) sales continue to grow as businesses and consumers move away from energy intensive incandescent light bulbs. An exchange in pollution media is occurring as airborne mercury emissions from coal-burning power plants, the largest anthropogenic source of mercury, are being reduced by lower energy demand and standards, while more universal solid waste containing mercury is generated each time a CFL is disposed. The treatment of CFLs as a 'universal waste' by the Environmental Protection Agency (EPA) led to the banning of non-household fluorescent bulbs from most municipal solid waste. Although the EPA encourages recycling of bulbs, industry currently recycles fluorescent lamps and CFLs at a rate of only 29%. Monitoring programs at the federal and state level have had only marginal success with industrial and business CFL recycling. The consumer recycling rate is even lower at only 2%. A projected increase in residential CFL use in Wisconsin owing to the ramifications of the Energy Independence and Security Act of 2007 will lead to elevated atmospheric mercury and landfill deposition in Wisconsin.

  12. Intraoperative Localization of Insulinoma and Normal Pancreas using Invisible Near-Infrared Fluorescent Light

    PubMed Central

    Winer, Joshua; Choi, Hak Soo; Gibbs-Strauss, Summer L.; Ashitate, Yoshitomo; Colson, Yolonda L.; Frangioni, John V.

    2009-01-01

    Background: Neuroendocrine tumors of the pancreas, such as insulinoma, are difficult to localize and complete resection is essential for cure. Our hypothesis is that a near-infrared (NIR) fluorophore exhibiting uptake in insulinoma could provide high sensitivity detection intraoperatively. Methods: The optical properties of methylene blue (MB) were measured in vitro in 100% serum at 37°C, and in vivo after tissue uptake. MB was injected as a rapid intravenous bolus at doses ranging from 0.25 to 2 mg/kg into wildtype rats and pigs, and into insulinoma-bearing transgenic mice. The FLARE™ imaging system was used to acquire color video and NIR fluorescence images simultaneously, and in real-time. The signal-to-background ratios (SBR) of tissues and tumors were quantified using FLARE™ software. Results: When appropriately diluted, MB exhibits moderate NIR fluorescence emission peaking at 688 nm. At doses ≥ 1 mg/kg, certain normal tissues, such as pancreas, accumulate MB and remain NIR fluorescent for up to 1 hr with an SBR ≥ 1.6. MB spectral properties are maintained after uptake into tissue. Interestingly, insulinoma exhibits even higher uptake for MB than normal pancreas, resulting in insulinoma-to-pancreas ratios of 3.7 and insulinoma-to-muscle ratios of 16.2. MB permitted high-sensitivity, real-time localization of primary, multi-centric, and metastatic insulinoma, and permitted differentiation among tumor, normal pancreas, and other abdominal structures. Conclusion: A single intravenous injection of a clinically available, commonly used NIR fluorophore provides prolonged intraoperative localization of normal pancreas and insulinoma using invisible NIR fluorescent light. PMID:20033320

  13. Estimate of federal relighting potential and demand for efficient lighting products

    SciTech Connect

    Shankle, S.A.; Dirks, J.A.; Elliott, D.B.; Richman, E.E.; Grover, S.E.

    1993-11-01

    The increasing level of electric utility rebates for energy-efficient lighting retrofits has recently prompted concern over the adequacy of the market supply of energy-efficient lighting products (Energy User News 1991). In support of the U.S. Department of Energy`s Federal Energy Management Program, Pacific Northwest Laboratory (PNL) has developed an estimate of the total potential for energy-efficient lighting retrofits in federally owned buildings. This estimate can be used to address the issue of the impact of federal relighting projects on the supply of energy-efficient lighting products. The estimate was developed in 1992, using 1991 data. Any investments in energy-efficient lighting products that occurred in 1992 will reduce the potential estimated here. This analysis proceeds by estimating the existing stock of lighting fixtures in federally owned buildings. The lighting technology screening matrix is then used to determine the minimum life-cycle cost retrofit for each type of existing lighting fixture. Estimates of the existing stock are developed for (1) four types of fluorescent lighting fixtures (2-, 3-, and 4-lamp, F40 4-foot fixtures, and 2-lamp, F96 8-foot fixtures, all with standard magnetic ballasts); (2) one type of incandescent fixture (a 75-watt single bulb fixture); and (3) one type of exit sign (containing two 20-watt incandescent bulbs). Estimates of the existing stock of lighting fixtures in federally owned buildings, estimates of the total potential demand for energy-efficient lighting products if all cost-effective retrofits were undertaken immediately, and total potential annual energy savings (in MWh and dollars), the total investment required to obtain the energy savings and the present value of the efficiency investment, are presented.

  14. Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting

    PubMed Central

    Toninelli, Andrea Efrem; Wang, Junfeng; Liu, Mingshen; Wu, Hong; Liu, Tianzhong

    2016-01-01

    This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m−2 d−1 biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase. PMID:27561323

  15. Enhancement of growth and lipid production from microalgae using fluorescent paint under the solar radiation.

    PubMed

    Seo, Yeong Hwan; Cho, Changsoon; Lee, Jung-Yong; Han, Jong-In

    2014-12-01

    Solar radiation has intensity that is too high to inhibit microalgae activity and is composed of wide light spectrum including ultraviolet (UV) range which cannot be utilized for microalgae. For these reasons, the modification of solar radiation is required for effective microalgae cultivation, and to do that, fluorescent paint was used for not only blocking excessive solar energy but also converting UV to visible light. With fluorescent aqueous layer, microalgae was protected from photoinhibition and could grow well, but there was difference in growth and lipid accumulation efficiencies depending on the color; maximum dry weight of 1.7 g/L was achieved in red paint, whereas best lipid content of 30% was obtained in blue one. This phenomenon was due to the different light spectrum made by colors. With simple process using fluorescent paint, modification of light was successfully done and allowing microalgae to grow under strong radiation such as solar radiation.

  16. State transitions and fluorescence quenching in the cyanobacterium Synechocystis PCC 6803 in response to changes in light quality and intensity.

    PubMed

    Zhao, Wenfeng; Xie, Jie; Xu, Xiuling; Zhao, Jingquan

    2015-01-01

    State transition and non-photochemical fluorescence quenching in cyanobacteria are short-term adaptations of photosynthetic apparatus to changes in light quality and intensity, however, the kinetic details and relationship are still not clear. In this work, time-dependent 77K fluorescence spectra were monitored for cyanobacterium Synechocystis PCC 6803 cells under blue, orange and blue-green light in a series of intensities. The characteristic fluorescence signals indicated state transition taking place exclusively under 430-450 or 580-600nm light or 480-550nm light at the intensities ⩽150μEm(-2)s(-1) to achieve a conserved level with variable rate constant. Under 480-500nm or 530-550nm light at the intensities ⩾160μEm(-2)s(-1), state transition took place at first but stopped as soon as the fluorescence quenching appeared. The dependence of appearance, induction period, level and rate constant for the quenching on light intensity suggests that a critical concentration of photo-activated OCPs is necessary and may be achieved by a dynamic equilibrium between the activation and deactivation under light.

  17. Relating productivity to visibility and lighting

    SciTech Connect

    Clear, R.; Berman, S.

    1982-01-01

    The problem of determining the appropriate light levels for visual tasks is a cost-benefit problem. Existing light level recommendations seriously underweight the importance of economic factors. Furthermore, the relative importance of the visibility factors in determining the optimal light levels appears inconsistent with the importance of these factors in determining visibility and visual performance. It is shown that calculations based on acuities give a lower limit of 100 to 200 lux for cost-effective light levels for office tasks. Upper limits are calculated from correlations of task performance to visibility levels. Visibility levels become progressively insensitive to luminance as luminance increases. Average power densities above 100 watts/m/sup 2/ are cost-effective only when visibility is very low. However, there is a 3-to-10 times larger increase in benefits from improving contrast or contrast sensitivity than from using more than 10 watts/m/sup 2/. Contrast or contrast sensitivity can be improved by using forms with larger print, using xerographic copy instead of carbon or mimeo, making sure office workers have the right eyeglasses, or even by transferring workers with visual problems to less visually demanding tasks. Once these changes are made it is no longer cost-effective to use more than 10 watts/m/sup 2/. This conclusion raises serious questions about recommendations that lead to greater than about 10 watts/m/sup 2/ of installed lighting for general office work.

  18. Developing methods based on light sheet fluorescence microscopy for biophysical investigations of larval zebrafish

    NASA Astrophysics Data System (ADS)

    Taormina, Michael J.

    Adapting the tools of optical microscopy to the large-scale dynamic systems encountered in the development of multicellular organisms provides a path toward understanding the physical processes necessary for complex life to form and function. Obtaining quantitatively meaningful results from such systems has been challenging due to difficulty spanning the spatial and temporal scales representative of the whole, while also observing the many individual members from which complex and collective behavior emerges. A three-dimensional imaging technique known as light sheet fluorescence microscopy provides a number of significant benefits for surmounting these challenges and studying developmental systems. A thin plane of fluorescence excitation light is produced such that it coincides with the focal plane of an imaging system, providing rapid acquisition of optically sectioned images that can be used to construct a three-dimensional rendition of a sample. I discuss the implementation of this technique for use in larva of the model vertebrate Danio rerio (zebrafish). The nature of light sheet imaging makes it especially well suited to the study of large systems while maintaining good spatial resolution and minimizing damage to the specimen from excessive exposure to excitation light. I show the results from a comparative study that demonstrates the ability to image certain developmental processes non-destructively, while in contrast confocal microscopy results in abnormal growth due to phototoxicity. I develop the application of light sheet microscopy to the study of a previously inaccessible system: the bacterial colonization of a host organism. Using the technique, we are able to obtain a survey of the intestinal tract of a larval zebrafish and observe the location of microbes as they grow and establish a stable population in an initially germ free fish. Finally, I describe a new technique to measure the fluid viscosity of this intestinal environment in vivo using

  19. Light emitting diode, photodiode-based fluorescence detection system for DNA analysis with microchip electrophoresis.

    PubMed

    Hall, Gordon H; Glerum, D Moira; Backhouse, Christopher J

    2016-02-01

    Electrophoretic separation of fluorescently end-labeled DNA after a PCR serves as a gold standard in genetic diagnostics. Because of their size and cost, instruments for this type of analysis have had limited market uptake, particularly for point-of-care applications. This might be changed through a higher level of system integration and lower instrument costs that can be realized through the use of LEDs for excitation and photodiodes for detection--if they provide sufficient sensitivity. Here, we demonstrate an optimized microchip electrophoresis instrument using polymeric fluidic chips with fluorescence detection of end-labeled DNA with a LOD of 0.15 nM of Alexa Fluor 532. This represents orders of magnitude improvement over previously reported instruments of this type. We demonstrate the system with an electrophoretic separation of two PCR products and their respective primers. We believe that this is the first LED-induced fluorescence microchip electrophoresis system with photodiode-based detection that could be used for standard applications of PCR and electrophoresis.

  20. Replacement of fluorescent lamps with high-brightness LEDs in a bridge lighting application

    NASA Astrophysics Data System (ADS)

    Curran, John W.; Keeney, Shawn P.

    2006-08-01

    There are many advantages that LEDs offer for use in general illumination. The use of LEDs in certain applications can provide improved energy efficiency. For example, in traffic lights in the United States, LED technology has taken over the market not only because of the energy savings as compared to standard incandescents, but also because of the reduced maintenance costs associated with bulb replacement and improved reliability. With useful lifetimes exceeding 40,000 hours or more, today's high flux LEDs can provide illumination solutions with replacement periods of 8 to 10 years or more. This paper will examine a bridge roadway lighting feasibility study which the authors' company recently undertook. The application required the LED units to reproduce the photometric performance of 64-inch (1.625m) fluorescent lamps. In addition, the LED units were required to survive a harsh, outdoor marine environment with an expected lifetime of 7 years or more. To achieve these results, a number of design elements were studied including: optimum heat dissipation in a sealed enclosure, ease of installation, and design of power supplies having expected lifetimes to match the LED light engines. Results of these studies will be discussed as well as illustrations of the designs chosen.

  1. Light-Emitting Diodes and Cool White Fluorescent Light Similarly Suppress Pineal Gland Melatonin and Maintain Retinal Function and Morphology in the Rat. Part 1

    NASA Technical Reports Server (NTRS)

    Holley, Daniel C.; Heeke, D.; Mele, G.

    1999-01-01

    Currently, the light sources most commonly used in animal habitat lighting are cool white fluorescent or incandescent lamps. We evaluated a novel light-emitting diode (LED) light source for use in animal habitat lighting by comparing its effectiveness to cool white fluorescent light (CWF) in suppressing pineal gland melatonin and maintaining normal retinal physiology and morphology in the rat. Results of pineal melatonin suppression experiments showed equal suppression of pineal melatonin concentrations for LED light and CWF light at five different light illuminances (100, 40, 10, 1 and 0.1 lux). There were no significant differences in melatonin suppression between LED and CWF light when compared to unexposed controls. Retinal physiology was evaluated using electroretinography. Results show no differences in a-wave implicit times and amplitudes or b-wave implicit times and amplitudes between 100-lux LED-exposed rats and 100-lux CWF-exposed rats. Results of retinal histology assessment show no differences in retinal thickness rod outer segment length and number of rod nuclei between rats exposed to 100-lux LED and 100-lux CWF for days. Furthermore, the retinal pigmented epithelium and rod outer segments of all eyes observed were in good condition and of normal thickness. This study indicates that LED light does not cause retinal damage and can suppress pineal melatonin at similar intensities as a conventional CWF light source. These data suggest that LED light sources may be suitable replacements for conventional light sources used in the lighting of rodent vivariums while providing many mechanical and economical advantages.

  2. Visible-light optical coherence tomography-based multimodal retinal imaging for improvement of fluorescent intensity quantification

    PubMed Central

    Nafar, Zahra; Jiang, Minshan; Wen, Rong; Jiao, Shuliang

    2016-01-01

    We developed a spectral-domain visible-light optical coherence tomography (VIS-OCT) based multimodal imaging technique which can accomplish simultaneous OCT and fluorescence imaging with a single broadband light source. Phantom experiments showed that by using the simultaneously acquired OCT images as a reference, the effect of light attenuation on the intensity of the fluorescent images by materials in front of the fluorescent target can be compensated. This capability of the multimodal imaging technique is of high importance for achieving quantification of the true intensities of autofluorescence (AF) imaging of the retina. We applied the technique in retinal imaging including AF imaging of the retinal pigment epithelium and fluorescein angiography (FA). We successfully demonstrated the effect of compensation on AF and FA images with the simultaneously acquired VIS-OCT images. PMID:27699094

  3. Enhanced photocatalytic inactivation of bacteria on Fe-containing TiO2 nanoparticles under fluorescent light.

    PubMed

    Yadav, Hemraj M; Kolekar, Tanaji V; Pawar, Shivaji H; Kim, Jung-Sik

    2016-03-01

    In this paper, the photocatalytic activity of Fe-TiO2 nanoparticles (NPs) under fluorescent light was studied using Escherichia coli and Staphylococcus aureus. Fe-TiO2 NPs were synthesized using a sol-gel method and characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS) and transmission electron microscopy. The efficiency of photocatalytic inactivation towards E. coli was studied under different physicochemical parameters. The photocatalytic inactivation rate increased with increasing Fe content in TiO2 NPs and the highest inactivation was achieved for 3.0 mol% Fe-TiO2 NPs under fluorescent light. These results demonstrate that the presence of an optimum concentration of Fe in TiO2 matrix enhances the photocatalytic inactivation of TiO2 NPs under fluorescent light.

  4. Production of green fluorescent protein in transgenic rice seeds.

    PubMed

    Li, Ding; Gao, Jing; Shen, Chunxiu; Fang, Zhen; Xia, Yumei; Yuan, Longping; Cao, Mengliang

    2013-03-01

    Immature embryos from immature seeds of rice (Oryza sativa L.) were transformed by biolistic bombardment with the plasmid carrying the coding region of the hygromycin phosphotransferase gene under the control of the 5' region of the cauliflower mosaic virus 35S promoter and the synthetic green fluorescence protein gene (sgfp) under the control of the maize ubiquitine promoter. Southern blot analysis confirmed the stable integration of hpt and sgfp genes in transformants. Subsequently leaves from regenerated plants were resistant to hygromycin, and microscopic observation of the green fluorescence and immunoblotting analysis revealed that green fluorescence protein was not only detected in the leaf and pollen of primary transformants but also in mature seeds. The results bear out the importance of the suitability of GFP as an in vivo marker to follow the processes of selection of somatic hybrid embryos and plants.

  5. Highly Efficient Sky-Blue Fluorescent Organic Light Emitting Diode Based on Mixed Cohost System for Thermally Activated Delayed Fluorescence Emitter (2CzPN).

    PubMed

    Sun, Jin Won; Kim, Kwon-Hyeon; Moon, Chang-Ki; Lee, Jeong-Hwan; Kim, Jang-Joo

    2016-04-20

    The mixed cohosts of 1,3-bis(N-carbazolyl)benzene and 2,8-bis(diphenylphosphoryl)dibenzothiophene have been developed for a highly efficient blue fluorescent oragnic light emitting diode (OLED) doped with a thermally activated delayed fluorescence (TADF) emitter [4,5-di (9H-carbazol-9-yl) phthalonitrile (2CzPN)]. We have demonstrated one of the highest external quantum efficiency of 21.8% in blue fluorescent OLEDs, which is identical to the theoretically achievable maximum electroluminescence efficiency using the emitter. Interestingly, the efficiency roll-off is large even under the excellent charge balance in the device and almost the same as the single host based devices, indicating that the efficiency roll-off in 2CzPN based TADF host is related to the material characteristics, such as low reverse intesystem crossing rate rather than charge imbalance.

  6. Assessing the Association between Oral Hygiene and Preterm Birth by Quantitative Light-Induced Fluorescence

    PubMed Central

    Hope, Christopher K.; Wang, Qian; Adeyemi, Adejumoke A.; Quenby, Siobhan; Smith, Philip W.; Higham, Susan M.; Whitworth, Melissa

    2014-01-01

    The aim of this study was to investigate the purported link between oral hygiene and preterm birth by using image analysis tools to quantify dental plaque biofilm. Volunteers (n = 91) attending an antenatal clinic were identified as those considered to be “at high risk” of preterm delivery (i.e., a previous history of idiopathic preterm delivery, case group) or those who were not considered to be at risk (control group). The women had images of their anterior teeth captured using quantitative light-induced fluorescence (QLF). These images were analysed to calculate the amount of red fluorescent plaque (ΔR%) and percentage of plaque coverage. QLF showed little difference in ΔR% between the two groups, 65.00% case versus 68.70% control, whereas there was 19.29% difference with regard to the mean plaque coverage, 25.50% case versus 20.58% control. A logistic regression model showed a significant association between plaque coverage and case/control status (P = 0.031), controlling for other potential predictor variables, namely, smoking status, maternal age, and body mass index (BMI). PMID:24511282

  7. Light induced fluorescence for predicting API content in tablets: sampling and error.

    PubMed

    Domike, Reuben; Ngai, Samuel; Cooney, Charles L

    2010-05-31

    The use of a light induced fluorescence (LIF) instrument to estimate the total content of fluorescent active pharmaceutical ingredient in a tablet from surface sampling was demonstrated. Different LIF sampling strategies were compared to a total tablet ultraviolet (UV) absorbance test for each tablet. Testing was completed on tablets with triamterene as the active ingredient and on tablets with caffeine as the active ingredient, each with a range of concentrations. The LIF instrument accurately estimated the active ingredient within 10% of total tablet test greater than 95% of the time. The largest error amongst all of the tablets tested was 13%. The RMSEP between the techniques was in the range of 4.4-7.9%. Theory of the error associated with the surface sampling was developed and found to accurately predict the experimental error. This theory uses one empirically determined parameter: the deviation of estimations at different locations on the tablet surface. As this empirical parameter can be found rapidly, correct use of this prediction of error may reduce the effort required for calibration and validation studies of non-destructive surface measurement techniques, and thereby rapidly determine appropriate analytical techniques for estimating content uniformity in tablets.

  8. Light-emitting diode and laser fluorescence-based devices in detecting occlusal caries

    NASA Astrophysics Data System (ADS)

    Rodrigues, Jonas A.; Hug, Isabel; Neuhaus, Klaus W.; Lussi, Adrian

    2011-10-01

    The aim of this study was to assess the performance of two light-emitting diode (LED)- and two laser fluorescence-based devices in detecting occlusal caries in vitro. Ninety-seven permanent molars were assessed twice by two examiners using two LED- (Midwest Caries - MID and VistaProof - VP) and two laser fluorescence-based (DIAGNOdent 2095 - LF and DIAGNOdent pen 2190 - LFpen) devices. After measuring, the teeth were histologically prepared and classified according to lesion extension. At D1 the specificities were 0.76 (LF and LFpen), 0.94 (MID), and 0.70 (VP); the sensitivities were 0.70 (LF), 0.62 (LFpen), 0.31 (MID), and 0.75 (VP). At D3 threshold the specificities were 0.88 (LF), 0.87 (LFpen), 0.90 (MID), and 0.70 (VP); the sensitivities were 0.63 (LF and LFpen), 0.70 (MID), and 0.96 (VP). Spearman's rank correlations with histology were 0.56 (LF), 0.51 (LFpen), 0.55 (MID), and 0.58 (VP). Inter- and intraexaminer ICC values were high and varied from 0.83 to 0.90. Both LF devices seemed to be useful auxiliary tools to the conventional methods, presenting good reproducibility and better accuracy at D3 threshold. MID was not able to differentiate sound surfaces from enamel caries and VP still needs improvement on the cut-off limits for its use.

  9. Robust measurement of membrane bending moduli using light sheet fluorescence imaging of vesicle fluctuations.

    PubMed

    Loftus, Andrew F; Noreng, Sigrid; Hsieh, Vivian L; Parthasarathy, Raghuveer

    2013-11-26

    The mechanical rigidity of lipid membranes is a key determinant of the energetics of cellular membrane deformation. Measurements of membrane bending moduli remain rare, however, and show a large variance, a situation that can be addressed by the development of improved techniques and by comparisons between disparate techniques applied to the same systems. We introduce here the use of selective plane illumination microscopy (SPIM, also known as light sheet fluorescence microscopy) to image thermal fluctuations of giant vesicles. The optical sectioning of SPIM enables high-speed fluorescence imaging of freely suspended vesicles and quantification of edge localization precision, yielding robust fluctuation spectra and rigidity estimates. For both lipid-only membranes and membranes bound by the intracellular trafficking protein Sar1p, which lowers membrane rigidity in a concentration-dependent manner, we show that the resulting bending modulus values are in close agreement with those derived from an independent assay based on membrane tether pulling. We also show that the fluctuation spectra of vesicles bound by the mammalian Sar1A protein, which stiffens membranes at high concentrations, are not well fit by a model of homogeneous quasi-spherical vesicles, suggesting that SPIM-based analysis can offer insights into spatially inhomogeneous properties induced by protein assemblies.

  10. Selective light-triggered chemiluminescence between fluorescent dyes and luminol, and its analytical application.

    PubMed

    Ma, Mingyang; Diao, Fangning; Zheng, Xingwang; Guo, Zhihui

    2012-08-01

    We report herein a novel chemiluminescence (CL) phenomenon triggered by light irradiation when a fluorescent dye, for example hematoporphyrin, fluorescein, eosin, or methylene blue is present in the luminol solution. A possible mechanism is proposed for the photoinduced chemiluminescence (PICL) reaction. Compared with reported methods for CL triggering, for example flow-injection, static reagent injection, and the electrochemical technique, the proposed in-situ PICL method presented has three advantages. First, the method is more selective, because the PICL signal of the target fluorescent dyes is initiated by excitation at a selective wavelength only. Second, the space and time resolution of the PICL method are better. Last, and most important, compared with injecting a reagent or inserting a electrode into the CL system to initiate the CL reaction, with the in-situ PICL method there is no physical interference with the target detecting system. All these advantages of the PICL method indicate it has many potential applications in the analytical sciences. The proposed method was applied to analysis of urine containing adrenaline. The linear range for adrenaline is 2.0 × 10(-10)-1.0 × 10(-7) g mL(-1) and the detection limit is 6.0 × 10(-11) g mL(-1).

  11. Eyecup scope—optical recordings of light stimulus-evoked fluorescence signals in the retina

    PubMed Central

    Hausselt, Susanne E.; Breuninger, Tobias; Castell, Xavier; Denk, Winfried; Margolis, David J.; Detwiler, Peter B.

    2009-01-01

    Dendritic signals play an essential role in processing visual information in the retina. To study them in neurites too small for electrical recording, we developed an instrument that combines a multi-photon (MP) microscope with a through-the-objective high-resolution visual stimulator. An upright microscope was designed that uses the objective lens for both MP imaging and delivery of visual stimuli to functionally intact retinal explants or eyecup preparations. The stimulator consists of a miniature liquid-crystal-on-silicon display coupled into the optical path of an infrared-excitation laser-scanning microscope. A pair of custom-made dichroic filters allows light from the excitation laser and three spectral bands (‘colors’) from the stimulator to reach the retina, leaving two intermediate bands for fluorescence imaging. Special optics allow displacement of the stimulator focus relative to the imaging focus. Spatially resolved changes in calcium-indicator fluorescence in response to visual stimuli were recorded in dendrites of different types of mammalian retinal neurons. PMID:19023590

  12. Polarized fluorescence and absorption of macroscopically aligned Light Harvesting Complex II.

    PubMed

    van Amerongen, H; Kwa, S L; van Bolhuis, B M; van Grondelle, R

    1994-08-01

    Polarized absorption and fluorescence measurements have been performed at 77 K on isotropic and anisotropic preparations of trimeric Light Harvesting Complex II (LHC-II) from spinach. The results enable a decomposition of the absorption spectrum into components parallel and perpendicular to the trimeric plane. For the first time, it is shown quantitatively that the strong absorption band around 676 nm is polarized essentially parallel to the plane of the trimer, i.e., the average angle between the corresponding transition dipole moments and this plane is at most 12 degrees. The different absorption bands for LHC-II should not be considered as corresponding to individual pigments but to collective excitations of different pigments. Nevertheless, the average angle between the Qy transition dipole moments of all chlorophyll a pigments in LHC-II and the trimeric plane could be determined and was found to be 17.5 degrees +/- 2.5 degrees. For the chlorophyll b pigments, this angle is significantly larger (close to 35 degrees). At 77 K, most of the fluorescence stems from a weak band above 676 nm and the corresponding transition dipole moments are oriented further out of plane than the dipole moments corresponding to the 676-nm band. The results are shown to be of crucial significance for understanding the relation between the LHC-II structure and its spectroscopy.

  13. Robust incremental compensation of the light attenuation with depth in 3D fluorescence microscopy.

    PubMed

    Kervrann, C; Legland, D; Pardini, L

    2004-06-01

    Summary Fluorescent signal intensities from confocal laser scanning microscopes (CLSM) suffer from several distortions inherent to the method. Namely, layers which lie deeper within the specimen are relatively dark due to absorption and scattering of both excitation and fluorescent light, photobleaching and/or other factors. Because of these effects, a quantitative analysis of images is not always possible without correction. Under certain assumptions, the decay of intensities can be estimated and used for a partial depth intensity correction. In this paper we propose an original robust incremental method for compensating the attenuation of intensity signals. Most previous correction methods are more or less empirical and based on fitting a decreasing parametric function to the section mean intensity curve computed by summing all pixel values in each section. The fitted curve is then used for the calculation of correction factors for each section and a new compensated sections series is computed. However, these methods do not perfectly correct the images. Hence, the algorithm we propose for the automatic correction of intensities relies on robust estimation, which automatically ignores pixels where measurements deviate from the decay model. It is based on techniques adopted from the computer vision literature for image motion estimation. The resulting algorithm is used to correct volumes acquired in CLSM. An implementation of such a restoration filter is discussed and examples of successful restorations are given.

  14. A wide field fluorescence lifetime imaging system using a light sheet microscope

    NASA Astrophysics Data System (ADS)

    Birch, Phil M.; Moore, Lamar; Li, Xiaofei; Phillips, Roger; Young, Rupert; Chatwin, Chris

    2016-04-01

    Fluorescence lifetime imaging microscopy (FLIM) has allowed scientists to discern information about the chemical properties of biological processes and has become a vital tool in the life sciences and medical research communities. Measuring the spatial lifetime distribution of the fluorophores as well as the intensity distribution enables users to discern vital information about the chemical environment. It however, remains challenging and often involves slow scanning. We present a new microscope system based on light sheet illumination that uses a micro channel plate (MCP) device called a Capacitive Division Imaging Readout (CDIR) which has been developed by Photek Ltd. The device uses an array of capacitors to move the charge site from the MCP to four pre-amplifiers and time-over-threshold discriminators. This camera has the ability to image photons as well as measure the arrival time, enabling high speed FLIM imaging of biological samples.

  15. Light Sheet Fluorescence Microscopy Quantifies Calcium Oscillations in Root Hairs of Arabidopsis thaliana.

    PubMed

    Candeo, Alessia; Doccula, Fabrizio G; Valentini, Gianluca; Bassi, Andrea; Costa, Alex

    2017-03-31

    Calcium oscillations play a role in the regulation of the development of tip-growing plant cells. Using optical microscopy, calcium oscillations have been observed in a few systems (e.g. pollen tubes, fungal hyphae, algal rhizoids). High resolution, non-phototoxic and rapid imaging methods are required to study the calcium oscillation in root hairs. We show that Light Sheet Fluorescence Microscopy is optimal to image growing root hairs of Arabidopsis thaliana and to follow their oscillatory tip-focused calcium gradient. We describe a protocol for performing live imaging of root hairs in seedlings expressing the cytosolic localised ratiometric calcium indicator Yellow Cameleon 3.6. Using this protocol, we measured the calcium gradient in a large number of root hairs. We characterised their calcium oscillations and correlated them with the rate of hair growth. The method was then used to screen the effect of auxin on the properties of the growing root hairs.

  16. Combined application of dynamic light scattering imaging and fluorescence intravital microscopy in vascular biology

    NASA Astrophysics Data System (ADS)

    Kalchenko, V.; Ziv, K.; Addadi, Y.; Madar-Balakirski, N.; Meglinski, I.; Neeman, M.; Harmelin, A.

    2010-08-01

    The dynamic light scattering imaging (DLSI) system combined with the conventional fluorescence intravital microscope (FIM) has been applied for the examination of blood and lymph vessels in the mouse ear in vivo. While the CCD camera can be shared by both techniques the combined application of DLSI and FIM allows rapid switching between the modalities. In current study temporal speckles fluctuations are used for rendering blood vessels structure and monitoring blood perfusion with the higher spatial resolution, whereas FIM provides the images of lymphatic vessels. The results clearly demonstrate that combined application of DLSI and FIM approaches provides synchronic in vivo images of blood and lymph vessels with higher contrast and specificity. The use of this new dual-modal diagnostic system is particularly important and has a great potential to significantly expand the capabilities of vascular diagnostics providing synchronic in vivo images of blood and lymph vessels.

  17. Red-emitting fluorescent organic light emitting diodes with low sensitivity to self-quenching

    NASA Astrophysics Data System (ADS)

    Forget, S.; Chenais, S.; Tondelier, D.; Geffroy, B.; Gozhyk, I.; Lebental, M.; Ishow, E.

    2010-09-01

    Concentration quenching is a major impediment to efficient organic light-emitting devices (OLEDs). We herein report on OLEDs based on a fluorescent amorphous red-emitting starbust triarylamine molecule [4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene, named FVIN], exhibiting a very small sensitivity to concentration quenching. OLEDs are fabricated with various doping levels of FVIN into Alq3, and show a remarkably stable external quantum efficiency of 1.5% for doping rates ranging from 5% up to 40%, which strongly relaxes the technological constraints on the doping accuracy. An efficiency of 1% is obtained for a pure undoped active region, along with deep red emission (x=0.6; y=0.35 in the Commission Internationale de l'Energie (CIE) coordinates). A comparison of FVIN with the archetypal 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye is presented in an identical multilayer OLED structure.

  18. High-efficiency fluorescent organic light-emitting diodes enabled by triplet-triplet annihilation and horizontal emitter orientation

    SciTech Connect

    Mayr, Christian Schmidt, Tobias D.; Brütting, Wolfgang

    2014-11-03

    A green organic light-emitting diode with the fluorescent emitter Coumarin 545T shows an external quantum efficiency (η{sub EQE}) of 6.9%, clearly exceeding the classical limit of 5% for fluorescent emitters. The analysis of the angular dependent photoluminescence spectrum of the emission layer reveals that 86% of the transition dipole moments are horizontally oriented. Furthermore, transient electroluminescence measurements demonstrate the presence of a delayed emission originating from triplet-triplet annihilation. A simulation based efficiency analysis reveals quantitatively the origin for the high η{sub EQE}: a radiative exciton fraction higher than 25% and a light-outcoupling efficiency of nearly 30%.

  19. Enhancing lutein productivity of an indigenous microalga Scenedesmus obliquus FSP-3 using light-related strategies.

    PubMed

    Ho, Shih-Hsin; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Wen-Lung; Lee, Duu-Jong; Chang, Jo-Shu

    2014-01-01

    Lutein, one of the main photosynthetic pigments, is a promising natural product with both nutritional and pharmaceutical applications. In this study, light-related strategies were applied to enhance the cell growth and lutein production of a lutein-rich microalga Scenedesmus obliquus FSP-3. The results demonstrate that using white LED resulted in better lutein production efficiency when compared to the other three monochromatic LEDs (red, blue, and green). The lutein productivity of S. obliquus FSP-3 was further improved by adjusting the type of light source and light intensity. The optimal lutein productivity of 4.08 mg/L/d was obtained when using a TL5 fluorescent lamp at a light intensity of 300 μmol/m(2)/s, and this performance is better than that reported in most related studies. Moreover, the time-course profile of lutein accumulation in the microalga shows that the maximal lutein content and productivity were obtained at the onset of nitrogen depletion.

  20. 78 FR 46368 - Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Termination of an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Dimmable Compact Fluorescent Lamps and Products Containing Same; Termination of an Investigation AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given...

  1. NLO Vector Boson Production With Light Jets

    SciTech Connect

    Bern, Z.; Diana, G.; Dixon, L.J.; Febres Cordero, F.; Forde, D.; Gleisberg, T.; Hoeche, S.; Ita, H.; Kosower, D.A.; Maitre, D.; Ozeren, K.

    2012-02-15

    In this contribution we present recent progress in the computation of next-to-leading order (NLO) QCD corrections for the production of an electroweak vector boson in association with jets at hadron colliders. We focus on results obtained using the virtual matrix element library BlackHat in conjunction with SHERPA, focusing on results relevant to understanding the background to top production. The production of a vector boson in association with several jets at the Large Hadron Collider (LHC) is an important background for other Standard Model processes as well as new physics signals. In particular, the production of a W boson in association with many jets is an important background for processes involving one or more top quarks. Precise predictions for the backgrounds are crucial to measurement of top-quark processes. Vector boson production in association with multiple jets is also a very important background for many SUSY searches, as it mimics the signatures of many typical decay chains. Here we will discuss how polarization information can be used as an additional handle to differentiate top pair production from 'prompt' W-boson production. More generally, ratios of observables, for example for events containing a W boson versus those containing a Z boson, are expected to be better-behaved as many uncertainties cancel in such ratios. Precise calculation of ratios, along with measurement of one of the two processes in the ratio, can be used in data-driven techniques for estimating backgrounds.

  2. Low-frequency wide-field fluorescence lifetime imaging using a high-power near-infrared light-emitting diode light source.

    PubMed

    Gioux, Sylvain; Lomnes, Stephen J; Choi, Hak Soo; Frangioni, John V

    2010-01-01

    Fluorescence lifetime imaging (FLi) could potentially improve exogenous near-infrared (NIR) fluorescence imaging, because it offers the capability of discriminating a signal of interest from background, provides real-time monitoring of a chemical environment, and permits the use of several different fluorescent dyes having the same emission wavelength. We present a high-power, LED-based, NIR light source for the clinical translation of wide-field (larger than 5 cm in diameter) FLi at frequencies up to 35 MHz. Lifetime imaging of indocyanine green (ICG), IRDye 800-CW, and 3,3(')-diethylthiatricarbocyanine iodide (DTTCI) was performed over a large field of view (10 cm by 7.5 cm) using the LED light source. For comparison, a laser diode light source was employed as a gold standard. Experiments were performed both on the bench by diluting the fluorescent dyes in various chemical environments in Eppendorf tubes, and in vivo by injecting the fluorescent dyes mixed in Matrigel subcutaneously into CD-1 mice. Last, measured fluorescence lifetimes obtained using the LED and the laser diode sources were compared with those obtained using a state-of-the-art time-domain imaging system and with those previously described in the literature. On average, lifetime values obtained using the LED and the laser diode light sources were consistent, exhibiting a mean difference of 3% from the expected values and a coefficient of variation of 12%. Taken together, our study offers an alternative to laser diodes for clinical translation of FLi and explores the use of relatively low frequency modulation for in vivo imaging.

  3. Quality and safety assessment of food and agricultural products by hyperspectral fluorescence imaging.

    PubMed

    Zhang, Ruoyu; Ying, Yibin; Rao, Xiuqin; Li, Jiangbo

    2012-09-01

    Hyperspectral fluorescence imaging (HSFI) is potentially useful for assessing food and agricultural products, because it combines the merits of both hyperspectral imaging and fluorescence spectroscopy. This paper provides an introduction to HSFI: the principle and components of HSFI, calibration and image processing are described. In addition, recent advances in the application of HSFI to food and agricultural product assessment are reviewed, such as contaminant detection, constituent analysis and quality evaluation. Finally, current limitations and likely future development trends are discussed.

  4. New global observations of the terrestrial carbon cycle from GOSAT: Patterns of vegetation fluorescence with gross primary productivity

    NASA Astrophysics Data System (ADS)

    Frankenberg, C.; Fisher, J. B.; Lee, J.; Guanter, L.; Van der Tol, C.; Toon, G. C.; kuze, A.; Yokota, T.; Badgley, G. M.; Butz, A.; Jung, M.; Saatchi, S. S.; Worden, J.

    2011-12-01

    Our ability to close the Earth's carbon budget and predict feedbacks in a warming climate depends critically on knowing where, when and how carbon dioxide is exchanged between the land and atmosphere. Terrestrial gross primary production (GPP) constitutes the largest flux component in the global carbon budget, however significant uncertainties remain in GPP estimates and its seasonality. Solar-induced chlorophyll fluorescence is a powerful proxy for assessing biomass photosynthetic activity since photosynthesis and fluorescence are directly coupled processes. This gives rise to re-emission of light between approximately 670 and 780 nm. Passive methods to quantify the fluorescence signal are mainly based on the filling-in of highly saturated O2 absorption structures. This method, however, was mostly applied in field-based measurements and is not directly applicable to space-borne retrievals. We show that variability of aerosols in the atmosphere load and surface pressure cannot be unequivocally disentangled from fluorescence since all these factor impact the absorption depths of O2 lines. This gives rise to biases in the retrieved scattering properties in typical multi-spectral XCO2 retrievals when using the O2 A band but not when focussing solely of solar Fraunhofer lines. We will a) present our retrieval method based on an iterative, non-linear least-squares fitting of Fraunhofer lines, b) discuss the potential impact on XCO2 retrievals and c) show recent fluorescence results from more than one year of GOSAT data. Empirically, we show that global spaceborne observations of solar induced chlorophyll fluorescence exhibit a strong linear correlation with GPP. We found that the fluorescence emission even without any additional meteorological, vegetation type or model information has the same or better predictive skill in estimating GPP as those derived from traditional remotely-sensed vegetation indices using ancillary data and model assumptions. Our results

  5. Efficient stray-light suppression for resonance fluorescence in quantum dot micropillars using self-aligned metal apertures

    NASA Astrophysics Data System (ADS)

    Hopfmann, Caspar; Musiał, Anna; Maier, Sebastian; Emmerling, Monika; Schneider, Christian; Höfling, Sven; Kamp, Martin; Reitzenstein, Stephan

    2016-09-01

    Within this work we propose and demonstrate a technological approach to efficiently suppress excitation laser stray-light in resonance fluorescence experiments on quantum dot micropillars. To ensure efficient stray-light suppression, their fabrication process includes a planarization step and subsequent covering with a titanium mask to fabricate self-aligned apertures at the micropillar positions. These apertures aim to limit laser stray-light in the side-excitation vertical-detection configuration, while enabling detection of the optical signal through the top facet of the micropillars. The beneficial effects of these apertures are proven and quantitatively evaluated within a statistical study in which we determine and compare the stray-light suppression of 48 micropillars with and without metal apertures. Actual resonance fluorescence experiments on single quantum dots coupled to the cavity mode prove the relevance of the proposed approach and demonstrate that it will foster further studies on cavity quantum electrodynamics phenomena under coherent optical excitation.

  6. Potential mercury emissions from fluorescent lamps production and obsolescence in mainland China.

    PubMed

    Tan, Quanyin; Li, Jinhui

    2016-01-01

    The use of fluorescent lamps has expanded rapidly all over the world in recent years, because of their energy-saving capability. Consequently, however, mercury emissions from production, breakage, and discard of the lamps are drawing increasing concern from the public. This article focuses on evaluating the amount of mercury used for fluorescent lamp production, as well as the potential mercury emissions during production and breakage, in mainland China. It is expected to provide a comprehensive understanding about the risks present in the mercury from fluorescent lamps, and to know about the impacts of the policies on fluorescent lamps after their implementation. It is estimated that, in 2020, mercury consumption will be about 11.30-15.69 tonnes, a significant reduction of 34.9%-37.4% from that used in 2013, owing to improvement in mercury dosing dosage technology and tighter limitations on mercury content in fluorescent lamps. With these improvements, the amount of mercury remaining in fluorescent lamps and released during production is estimated to be 10.71-14.86 and 0.59-0.83 tonnes, respectively; the mercury released from waste fluorescent lamps is estimated to be about 5.37-7.59 tonnes. Also, a significant reduction to the mercury emission can be expected when a collection and treatment system is well established and conducted in the future.

  7. Virtual unfolding of light sheet fluorescence microscopy dataset for quantitative analysis of the mouse intestine

    NASA Astrophysics Data System (ADS)

    Candeo, Alessia; Sana, Ilenia; Ferrari, Eleonora; Maiuri, Luigi; D'Andrea, Cosimo; Valentini, Gianluca; Bassi, Andrea

    2016-05-01

    Light sheet fluorescence microscopy has proven to be a powerful tool to image fixed and chemically cleared samples, providing in depth and high resolution reconstructions of intact mouse organs. We applied light sheet microscopy to image the mouse intestine. We found that large portions of the sample can be readily visualized, assessing the organ status and highlighting the presence of regions with impaired morphology. Yet, three-dimensional (3-D) sectioning of the intestine leads to a large dataset that produces unnecessary storage and processing overload. We developed a routine that extracts the relevant information from a large image stack and provides quantitative analysis of the intestine morphology. This result was achieved by a three step procedure consisting of: (1) virtually unfold the 3-D reconstruction of the intestine; (2) observe it layer-by-layer; and (3) identify distinct villi and statistically analyze multiple samples belonging to different intestinal regions. Even if the procedure has been developed for the murine intestine, most of the underlying concepts have a general applicability.

  8. Analysis of Compact Fluorescent Lights for Use by Patients with Photosensitive Conditions

    PubMed Central

    Klein, Rachel S.; Werth, Victoria P.; Dowdy, John C.; Sayre, Robert M.

    2010-01-01

    Ultraviolet radiation (UVR) is hazardous to patients with photosensitive skin disorders, such as lupus erythematosus, xeroderma pigmentosum and skin cancer. As such, these patients are advised to minimize their exposure to UVR. Classically, this is accomplished through careful avoidance of sun exposure and artificial tanning booths. Indoor light bulbs, however, are generally not considered to pose significant UVR hazard. We sought to test this notion by measuring the UV emissions of 19 different compact fluorescent light bulbs. The ability to induce skin damage was assessed with the CIE erythema action spectrum, ANSI S(λ) generalized UV hazard spectrum and the CIE photocarcinogenesis action spectrum. The results indicate that there is a great deal of variation amongst different bulbs, even within the same class. Although the irradiance of any given bulb is low, the possible daily exposure time is rather lengthy. This results in potential daily UVR doses ranging from 0.1 to 625 mJ cm−2, including a daily UVB (290–320 nm) dose of 0.01 to 15 mJ cm−2. Because patients are exposed continually over long time frames, this could lead to significant cumulative damage. It would therefore be prudent for patients to use bulbs with the lowest UV irradiance. PMID:19320850

  9. Stripe artifact elimination based on nonsubsampled contourlet transform for light sheet fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Liang, Xiao; Zang, Yali; Dong, Di; Zhang, Liwen; Fang, Mengjie; Yang, Xin; Arranz, Alicia; Ripoll, Jorge; Hui, Hui; Tian, Jie

    2016-10-01

    Stripe artifacts, caused by high-absorption or high-scattering structures in the illumination light path, are a common drawback in both unidirectional and multidirectional light sheet fluorescence microscopy (LSFM), significantly deteriorating image quality. To circumvent this problem, we present an effective multidirectional stripe remover (MDSR) method based on nonsubsampled contourlet transform (NSCT), which can be used for both unidirectional and multidirectional LSFM. In MDSR, a fast Fourier transform (FFT) filter is designed in the NSCT domain to shrink the stripe components and eliminate the noise. Benefiting from the properties of being multiscale and multidirectional, MDSR succeeds in eliminating stripe artifacts in both unidirectional and multidirectional LSFM. To validate the method, MDSR has been tested on images from a custom-made unidirectional LSFM system and a commercial multidirectional LSFM system, clearly demonstrating that MDSR effectively removes most of the stripe artifacts. Moreover, we performed a comparative experiment with the variational stationary noise remover and the wavelet-FFT methods and quantitatively analyzed the results with a peak signal-to-noise ratio, showing an improved noise removal when using the MDSR method.

  10. Imaging of trabecular meshwork using Bessel–Gauss light sheet with fluorescence

    NASA Astrophysics Data System (ADS)

    Jie Jeesmond Hong, Xun; Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, Tin

    2017-03-01

    Ocular imaging technology that holds promise for both fundamental investigation and clinical detection of glaucoma is still a challenging research area. A direct view of the trabecular meshwork (TM) with high resolution is not generally possible because the iridocorneal angle region is obstructed by the sclera overlap. The best approach to observe the aqueous outflow system (AOS) is therefore to view from the opposite angle. In this research work, we developed two imaging systems for the high resolution ex vivo studies of the AOS inside porcine eye, based on a Gaussian illuminated and a digitally scanned Bessel–Gauss beam light sheet fluorescence configurations. The digitally scanned Bessel–Gauss beam is able to overcome the trade-off between the length and thickness of the Gaussian light sheet to give better imaging performance. It has adequate spatial resolution to resolve critical anatomical structures such as the TM, thereby enabling objective information about the AOS. This non-contact and non-invasive imaging methodology with excellent safety profile is expected to be well received by vision researchers and clinicians in the evaluation and management of glaucoma.

  11. Enantiomerically pure trans-beta-lactams from alpha-amino acids via compact fluorescent light (CFL) continuous-flow photolysis.

    PubMed

    Vaske, Yvette S Mimieux; Mahoney, Maximillian E; Konopelski, Joseph P; Rogow, David L; McDonald, William J

    2010-08-18

    Photolysis of alpha-diazo-N-methoxy-N-methyl (Weinreb) beta-ketoamides derived from enantiomerically pure (EP) alpha-amino acids affords the corresponding EP beta-lactams via an intramolecular Wolff rearrangement. The photochemistry is promoted with either standard UV irradiation or through the use of a 100 W compact fluorescent light; the latter affords a safe and environmentally friendly alternative to standard photolysis conditions. A continuous-flow photochemical reactor made from inexpensive laboratory equipment reduced reaction times and was amenable to scale-up. The diastereoselectivity (cis or trans) of the product beta-lactams has been shown to vary from modest to nearly complete. An extremely facile, atom-economical method for the epimerization of the product mixture to the trans isomer, which is generally highly crystalline, has been developed. Evidence for C3 epimerization of Weinreb amide structures via a nonbasic, purely thermal route is presented. Subsequent transformations of both the Weinreb amide at C3 (beta-lactam numbering) and the amino acid side chain at C4 are well-tolerated, allowing for a versatile approach to diverse beta-lactam structures. The technology is showcased in the synthesis of a common intermediate used toward several carbapenem-derived structures starting from unfunctionalized aspartic acid.

  12. Enantiomerically Pure trans-β-Lactams from α-Amino Acids via Compact Fluorescent Light (CFL) Continuous Flow Photolysis

    PubMed Central

    Mimieux Vaske, Yvette S.; Mahoney, Maximillian E.; Konopelski, Joseph P.; Rogow, David L.; McDonald, William J.

    2010-01-01

    Photolysis of α-diazo N-methoxy-N-methyl (Weinreb) β-ketoamides derived from enantiomerically pure (EP) α-amino acids affords the corresponding EP β-lactam via an intramolecular Wolff rearrangement. Photochemistry is promoted with either standard UV irradiation or through the use of a 100W compact fluorescent light (CFL); the latter affords a safe and environmentally friendly alternative to standard photolysis conditions. A continuous-flow photochemical reactor, made from inexpensive laboratory equipment, expedites reaction times and is amenable to scale-up. Diastereoselectivity (cis or trans) of the product β-lactams has been shown to vary from modest to nearly complete. An extremely facile, atom-economical method for the epimerization of the product mixture to the trans isomer, generally highly crystalline, has been developed. Evidence is presented for C-3 epimerization of Weinreb amide structures via a non-basic, purely thermal route. Subsequent transformations of both the Weinreb amide at C-3 (β-lactam numbering) and amino acid side chain at C-4 are well tolerated, allowing for a versatile approach to diverse β-lactam structures. The technology is showcased in the synthesis of a common intermediate used toward several carbapenem-derived structures starting from unfunctionalized aspartic acid. PMID:20698705

  13. Lighting up G protein-coupled purinergic receptors with engineered fluorescent ligands

    PubMed Central

    Ciruela, Francisco; Fernández-Dueñas, Víctor; Jacobson, Kenneth A.

    2015-01-01

    The use of G protein-coupled receptors fluorescent ligands is undergoing continuous expansion. In line with this, fluorescent agonists and antagonists of high affinity for G protein-coupled adenosine and P2Y receptors have been shown to be useful pharmacological probe compounds. Fluorescent ligands for A1R, A2AR, and A3R (adenosine receptors) and P2Y2R, P2Y4R, P2Y6R, and P2Y14R (nucleotide receptors) have been reported. Such ligands have been successfully applied to drug discovery and to GPCR characterization by flow cytometry, fluorescence correlation spectroscopy, fluorescence microscopy, fluorescence polarization, fluorescence resonance energy transfer and scanning confocal microscopy. Here we summarize recently reported and readily available representative fluorescent ligands of purinergic receptors. In addition, we pay special attention on the use of this family of fluorescent ligands revealing two main aspects of purinergic receptor biology, namely ligand binding and receptor oligomerization. PMID:25890205

  14. Production Process for Strong, Light Ceramic Tiles

    NASA Technical Reports Server (NTRS)

    Holmquist, G. R.; Cordia, E. R.; Tomer, R. S.

    1985-01-01

    Proportions of ingredients and sintering time/temperature schedule changed. Production process for lightweight, high-strength ceramic insulating tiles for Space Shuttle more than just scaled-up version of laboratory process for making small tiles. Boron in aluminum borosilicate fibers allows fusion at points where fibers contact each other during sintering, thereby greatly strengthening tiles structure.

  15. Elemental mercury emission in the indoor environment due to broken compact fluorescent light (CFL) bulbs--paper

    EPA Science Inventory

    Compact fluorescent light (CFL) bulbs contain a few milligrams (mg) of elemental mercury. When a CFL breaks, some of the mercury is immediately released as elemental mercury vapor and the remainder is deposited on indoor surfaces with the bulb debris. In a controlled study design...

  16. Application of CORSIKA Simulation Code to Study Lateral and Longitudinal Distribution of Fluorescence Light in Cosmic Ray Extensive Air Showers

    NASA Astrophysics Data System (ADS)

    Bagheri, Zahra; Davoudifar, Pantea; Rastegarzadeh, Gohar; Shayan, Milad

    2017-03-01

    In this paper, we used CORSIKA code to understand the characteristics of cosmic ray induced showers at extremely high energy as a function of energy, detector distance to shower axis, number, and density of secondary charged particles and the nature particle producing the shower. Based on the standard properties of the atmosphere, lateral and longitudinal development of the shower for photons and electrons has been investigated. Fluorescent light has been collected by the detector for protons, helium, oxygen, silicon, calcium and iron primary cosmic rays in different energies. So we have obtained a number of electrons per unit area, distance to the shower axis, shape function of particles density, percentage of fluorescent light, lateral distribution of energy dissipated in the atmosphere and visual field angle of detector as well as size of the shower image. We have also shown that location of highest percentage of fluorescence light is directly proportional to atomic number of elements. Also we have shown when the distance from shower axis increases and the shape function of particles density decreases severely. At the first stages of development, shower axis distance from detector is high and visual field angle is small; then with shower moving toward the Earth, angle increases. Overall, in higher energies, the fluorescent light method has more efficiency. The paper provides standard calibration lines for high energy showers which can be used to determine the nature of the particles.

  17. Using peel fluorescence in black light rooms to identify navel oranges with shorter storage life and poor rind quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this project is to minimize postharvest decay losses of fresh citrus fruits. Among the approaches recently examined was peel fluorescence under ultraviolet light. In addition to its usual application to identify fruit with developing decay lesions (“blister” or “clear” rot) in black...

  18. Improving recombinant protein production in the Chlamydomonas reinhardtii chloroplast using vivid Verde Fluorescent Protein as a reporter.

    PubMed

    Braun-Galleani, Stephanie; Baganz, Frank; Purton, Saul

    2015-08-01

    Microalgae have potential as platforms for the synthesis of high-value recombinant proteins due to their many beneficial attributes including ease of cultivation, lack of pathogenic agents, and low-cost downstream processing. However, current recombinant protein levels are low compared to other microbial platforms and stable insertion of transgenes is available in only a few microalgal species. We have explored different strategies aimed at increasing growth rate and recombinant protein production in the Chlamydomonas reinhardtii chloroplast. A novel fluorescent protein (vivid Verde Fluorescent Protein, VFP) was expressed under the control of the native atpA promoter/5'UTR element. VFP levels were detected by western blotting, with increased protein levels observed when co-expressed with a gene encoding the Escherichia coli Spy chaperone. We used these transformant lines to study the effect of temperature, light and media on recombinant protein production and cell growth. VFP levels and fluorescence, assessed by flow cytometry, allowed a determination of improved cultivation conditions as 30°C under mixotrophic mode. These conditions were tested for the accumulation of an antimicrobial endolysin (Cpl-1) of potential commercial interest, observing that the outcome obtained for VFP could not be easily replicated for Cpl-1. This study suggests that recombinant protein expression is product-specific and needs to be optimized individually.

  19. Light sheet-based fluorescence microscopy (LSFM) reduces phototoxic effects and provides new means for the modern life sciences

    NASA Astrophysics Data System (ADS)

    Pampaloni, Francesco; Ansari, Nari; Girard, Philippe; Stelzer, Ernst H. K.

    2011-07-01

    Most optical technologies are applied to flat, basically two-dimensional cellular systems. However, physiological meaningful information relies on the morphology, the mechanical properties and the biochemistry of a cell's context. A cell requires the complex three-dimensional relationship to other cells. However, the observation of multi-cellular biological specimens remains a challenge. Specimens scatter and absorb light, thus, the delivery of the probing light and the collection of the signal light become inefficient; many endogenous biochemical compounds also absorb light and suffer degradation of some sort (photo-toxicity), which induces malfunction of a specimen. In conventional and confocal fluorescence microscopy, whenever a single plane, the entire specimen is illuminated. Recording stacks of images along the optical Z-axis thus illuminates the entire specimen once for each plane. Hence, cells are illuminated 10-20 and fish 100-300 times more often than they are observed. This can be avoided by changing the optical arrangement. The basic idea is to use light sheets, which are fed into the specimen from the side and overlap with the focal plane of a wide-field fluorescence microscope. In contrast to an epi-fluorescence arrangement, such an azimuthal fluorescence arrangement uses two independently operated lenses for illumination and detection. Optical sectioning and no photo-toxic damage or photo-bleaching outside a small volume close to the focal plane are intrinsic properties. Light sheet-based fluorescence microscopy (LSFM) takes advantage of modern camera technologies. LSFM can be operated with laser cutters and for fluorescence correlation spectroscopy. During the last few years, LSFM was used to record zebrafish development from the early 32-cell stage until late neurulation with sub-cellular resolution and short sampling periods (60-90 sec/stack). The recording speed was five 4-Megapixel large frames/sec with a dynamic range of 12-14 bit. We followed

  20. Detection of Biomass in New York City Aerosols: Light Scattering and Optical Fluorescence Techniques

    NASA Astrophysics Data System (ADS)

    Niebauer, M.; Alimova, A.; Katz, A.; Xu, M.; Rudolph, E.; Steiner, J.; Alfano, R. R.

    2005-12-01

    Optical spectroscopy is an ideal method for detecting bacteria and spores in real time. Optical fluorescence spectroscopy examination of New York City aerosols is used to quantify the mass of bacteria spores present in air masses collected at 14 liters/minute onto silica fiber filters, and on silica fiber ribbons using an Environmental Beta Attenuation Monitor manufactured by MetOne Instruments configured for the PM2.5 fraction. Dipicolinic acid (DPA), a molecule found primarily in bacterial spores, is the most characteristic component of spores in trial experiments on over 200 collected aerosol samples. DPA is extracted from the spores using a heat bath and chelated with Terbium. The DPA:Tb is detected by measuring its characteristic fluorescence with emission bands at 490, 545 and 585 nm for 270 nm excitation. Light scattering also measures the size distribution for a number of a variety of bacteria - Bacillus subtilis (rod shaped), Staphylococcus aureus (spherical) and Pseudomonas aeruginosa (short rods) establishing that optical techniques satisfactorily distinguish populations based on their variable morphology. Size and morphology are obtained by applying a variation of the Gaussian Ray Approximation theory of anomalous diffraction theory to an analysis of the transmission spectra in the range of 0.4 to 1.0 microns. In test experiments, the refractive index of the inner spore core of Bacillus subtilis decreases from 1.51 to 1.39 while the spore radius enlarges from 0.38 to 0.6 micrometers. Optical determinations are verified by oil-immersion techniques and by scanning electron microscope measurements. Characterization of spores, germinating spore materials, and bacteria is considered vital to tracing bacteria in the environment, for the development of life-detection systems for planetary exploration, monitoring pathogens in environmental systems, and for the preparation of anti-terrorism strategies.

  1. Melatonin production and light exposure of rotating night workers.

    PubMed

    Dumont, Marie; Lanctôt, Valérie; Cadieux-Viau, Raphaëlle; Paquet, Jean

    2012-03-01

    Decreased melatonin production, due to acute suppression of pineal melatonin secretion by light exposure during night work, has been suggested to underlie higher cancer risks associated with prolonged experience of night work. However, the association between light exposure and melatonin production has never been measured in the field. In this study, 24-h melatonin production and ambulatory light exposure were assessed during both night-shift and day/evening-shift periods in 13 full-time rotating shiftworkers. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s), and light exposure was measured with an ambulatory photometer. There was no difference in total 24-h aMT6s excretion between the two work periods. The night-shift period was characterized by a desynchrony between melatonin and sleep-wake rhythms, as shown by higher melatonin production during work and lower melatonin production during sleep when working night shifts than when working day/evening shifts. Light exposure during night work showed no correlation with aMT6s excreted during the night of work (p > .5), or with the difference in 24-h aMT6s excretion between the two work periods (p > .1). However, light exposure during night work was negatively correlated with total 24-h aMT6s excretion over the entire night-shift period (p < .01). In conclusion, there was no evidence of direct melatonin suppression during night work in this population. However, higher levels of light exposure during night work may have decreased total melatonin production, possibly by initiating re-entrainment and causing internal desynchrony. This interpretation is consistent with the proposition that circadian disruption, of which decreased melatonin production is only one of the adverse consequences, could be the mediator between night shiftwork and cancer risks.

  2. Potential environmental impacts from the metals in incandescent, compact fluorescent lamp (CFL), and light-emitting diode (LED) bulbs.

    PubMed

    Lim, Seong-Rin; Kang, Daniel; Ogunseitan, Oladele A; Schoenung, Julie M

    2013-01-15

    Artificial lighting systems are transitioning from incandescent to compact fluorescent lamp (CFL) and light-emitting diode (LED) bulbs in response to the U.S. Energy Independence and Security Act and the EU Ecodesign Directive, which leads to energy savings and reduced greenhouse gas emissions. Although CFLs and LEDs are more energy-efficient than incandescent bulbs, they require more metal-containing components. There is uncertainty about the potential environmental impacts of these components and whether special provisions must be made for their disposal at the end of useful life. Therefore, the objective of this study is to analyze the resource depletion and toxicity potentials from the metals in incandescent, CFL, and LED bulbs to complement the development of sustainable energy policy. We assessed the potentials by examining whether the lighting products are to be categorized as hazardous waste under existing U.S. federal and California state regulations and by applying life cycle impact-based and hazard-based assessment methods (note that "life cycle impact-based method" does not mean a general life cycle assessment (LCA) but rather the elements in LCA used to quantify toxicity potentials). We discovered that both CFL and LED bulbs are categorized as hazardous, due to excessive levels of lead (Pb) leachability (132 and 44 mg/L, respectively; regulatory limit: 5) and the high contents of copper (111,000 and 31,600 mg/kg, respectively; limit: 2500), lead (3860 mg/kg for the CFL bulb; limit: 1000), and zinc (34,500 mg/kg for the CFL bulb; limit: 5000), while the incandescent bulb is not hazardous (note that the results for CFL bulbs excluded mercury vapor not captured during sample preparation). The CFLs and LEDs have higher resource depletion and toxicity potentials than the incandescent bulb due primarily to their high aluminum, copper, gold, lead, silver, and zinc. Comparing the bulbs on an equivalent quantity basis with respect to the expected lifetimes of

  3. 75 FR 36119 - In the Matter of Certain Cold Cathode Fluorescent Lamp (“CCFL”) Inverter Circuits and Products...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Cold Cathode Fluorescent Lamp (``CCFL'') Inverter Circuits and Products... United States after importation of certain cold cathode fluorescent lamp inverter circuits and...

  4. 78 FR 16709 - Certain Cold Cathode Fluorescent Lamp (“CCFL”) Inverter Circuits and Products Containing Same...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-18

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Cold Cathode Fluorescent Lamp (``CCFL'') Inverter Circuits and Products Containing Same... importation, and the sale within the United States after importation of certain cold cathode fluorescent...

  5. Electromagnetic production of very light gluinos

    SciTech Connect

    Carlson, C.E.; Sher, M.; Weinstein, L.

    1994-04-01

    Current experiments allow the possibility of gluino masses below about 600 MeV if the lifetime of the gluino is longer than 100 picoseconds. If the mass and lifetime are in this window, then electromagnetic production of pairs of gluino-gluon bound states can provide a means to observe them. The cross section is large enough that the window can be fully explored, up to lifetimes exceeding a microsecond, at high luminosity electron accelerators. A discussion of signatures and a table of event rates for various possibilities at CEBAF is given.

  6. Supplementary artificial light to increase egg production of geese under natural lighting conditions.

    PubMed

    Wang, Chin-Meng; Chen, Lih-Ren; Lee, Shuen-Rong; Jea, Yu-Shine; Kao, Jung-Yie

    2009-07-01

    A new supplementary lighting program was designed to increase the egg production of geese under natural light conditions. The objective of this study was to evaluate the effects of the supplementary lighting program on egg production of White Roman geese in an open housing system at the Tropic of Cancer. Forty mature White Roman geese were randomly allocated into two groups (male:female=1:4). The supplementary lighting program with a total daily photoperiod of between 12.0 h and 13.5 h was initiated on 1 November and withdrawn from the experimental group on 30 January. In contrast, the geese in the control group were kept under natural lighting conditions throughout this study. The results showed that the laying peak of the experimental group occurred earlier than normal in the reproductive season and the geese continued laying throughout the breeding season. The geese in the experimental group had 47.6 eggs/goose which was significantly (P<0.05) more than that of the control group having 26.4 eggs/goose. We can conclude that the supplemental lighting method will result in an earlier laying peak of the geese in the breeding season and higher egg production. The supplementary lighting program was able to maximize egg production in geese at the Tropic of Cancer.

  7. Lighting for summer egg production by turkeys: day length and light intensity.

    PubMed

    Siopes, T D

    2007-11-01

    This experiment tested the hypothesis that typical poor egg production during the summer is a consequence of insufficient lighting and reduced photoperiodic drive. Large White turkey breeder hens were photostimulated at 30 wk of age with incandescent light on May 12 for summer (off-season) egg production and continued for 28 wk. The lighting treatments were given in a 2 x 2 factorial arrangement with day length and light intensity as main effects. Day lengths used were 15L:9D and 18L:6D, whereas the intensities were 567 +/- 67 and 22 +/- 2 lx. All the treatments were within a light-controlled building, and there were 8 replicate pens of 4 hens for each treatment. Data were collected, by pen, for onset and the rate of lay; BW and feed consumption at 4-wk intervals; and egg weight (EW) at 4-wk intervals including the weight of the first 14 eggs laid, livability, and plasma thyroid hormones for 8 wk postlighting. The rate of egg production through 28 wk of photostimulation was better in the hens receiving 18 than 15 h of light per day (14 eggs/hen difference) but was similar between the 2 intensity treatments. The lower number of eggs in the 15-h group was associated with a greater number of photorefractory hens than in the 18 h of light per day group (39 vs. 14%, respectively). Egg weights were similar between the 18 and 15 h of light/day treatment groups but was significantly greater in the low intensity treatment as compared with the high intensity treatment. We may conclude that by increasing photoperiodic drive by increased day length, but not light intensity, there results an improved summer egg production by turkeys and reduced incidence of photorefractoriness. Egg weight was best at a reduced light intensity.

  8. Maximizing Light Utilization Efficiency and Hydrogen Production in Microalgal Cultures

    SciTech Connect

    Melis, Anastasios

    2014-12-31

    The project addressed the following technical barrier from the Biological Hydrogen Production section of the Fuel Cell Technologies Program Multi-Year Research, Development and Demonstration Plan: Low Sunlight Utilization Efficiency in Photobiological Hydrogen Production is due to a Large Photosystem Chlorophyll Antenna Size in Photosynthetic Microorganisms (Barrier AN: Light Utilization Efficiency).

  9. Improving the estimation of terrestrial gross primary productivity by downscaling global sun-induced chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Cescatti, A.; Duveiller, G.

    2015-12-01

    The synoptic nature of satellite remote sensing makes this technique a key tool to contribute to estimating the amount of Carbon fixed by vegetation at global scale. From the various types of information that can be derived from space, the recent capacity to create global datasets of sun-induced chlorophyll fluorescence (SIF) may prove to be a game-changer. SIF is a signal emitted by the photosynthetic machinery itself that, under the illumination conditions in which it can be estimated by satellite, has been shown to be proportional to gross primary productivity (GPP). However, this relationship is dependent on vegetation types that are typically spatially mixed at the coarse spatial resolution of SIF datasets (at best 0.5°), which in turn is a consequence of the complexity of the SIF retrieval itself. This study demonstrates how 0.5° SIF derived from GOME-2 data can be downscaled to a more adequate spatial resolution of 0.05° by combining 3 explanatory biophysical variables derived from the MODIS sensor (NDVI, land surface temperature and evapotranspiration) under a semi-empirical light-use efficiency framework. The finer spatial resolution results in a cleaner signal when aggregating it per land cover type. The signal is also better correlated in time with GPP estimated from flux towers, reaching the same level of performance than global GPP products calibrated on such flux towers and driven by meteorological and remote sensing variables (other than SIF). Establishing linear relationships between SIF and flux-tower GPP at vegetation type level allows to estimate values of global terrestrial vegetation gross productivity that have different magnitude but similar temporal patterns as other GPP products. Based on downscaled SIF, the mean global GPP values over the period 2007 to 2013 are (for deciduous broadleaf and mixed forests) 13.7, (for evergreen needleleaf forests) 2.5, (for grasslands) 12.5 and (savannahs and woody savannas) 36.8 Pg of Carbon per year.

  10. Fluorescence of aqueous solutions of commercial humic products

    NASA Astrophysics Data System (ADS)

    Gosteva, O. Yu.; Izosimov, A. A.; Patsaeva, S. V.; Yuzhakov, V. I.; Yakimenko, O. S.

    2012-01-01

    We have studied the spectral luminescence characteristics of aqueous solutions of humic products obtained from different raw material sources, and their behavior as the excitation wavelength increases from 270 nm to 355 nm. We have identified differences in the spectral properties of industrial humic products from coalified materials, lignin-containing organic waste, and humic products from plant raw material (peat, sapropel, vermicompost). We have shown that humic products from plant raw material have spectral properties closer to those for humic substances in natural water or soil than humic products from coalified materials.

  11. Remote sensing for oil products on water surface via fluorescence induced by UV filaments

    NASA Astrophysics Data System (ADS)

    Sunchugasheva, E. S.; Ionin, A. A.; Mokrousova, D. V.; Seleznev, L. V.; Sinitsyn, D. V.; Geints, Yu. E.; Zemlyanov, A. A.

    2016-10-01

    Remote monitoring of water pollution, namely thin films of oil or oil products on water surface, can be carried out by laser fluorimetry. The pollutants fluorescence during its interaction with ultrashort UV laser pulses was experimentally studied in this paper. The laser pulses power was considered in a wide range of values including the filamentation regime. We compared fluorescence stimulated by femtosecond UV laser pulses with two central wavelengths (248 and 372 nm) for detection of crude oil and the following oil products: oil VM-5, oil 5W-40 and solvent WhiteSpirit. It was shown that shorter UV wavelengths are more suitable for fluorescence excitation. The spatial resolution of the fluorescence localization was no worse than 30 cm. We discuss techniques of high intensity emission delivery to the remote target as post-filamentation channels and multifilamentation beam propagation regime as well experimentally and numerically.

  12. [Hydrogen production by the cyanobacterium Anabaena variablis in the light].

    PubMed

    Gogotov, I N; Kosiak, A V; Krupenko, A N

    1976-01-01

    Light of low intensity (less than or equal to 25-10(5) erg-cm(-2)-sec(-1)) stimulates hydrogen production by cell suspensions of Anabaena variabilis in the presence of glucose, pyruvate or formate. The maximum rate of hydrogen production in the presence of these substrates was observed at light intensities of 650, 1400 and 2250 erg-cm(-2)-sec(-1), respectively. The rate of oxygen production by the cells increases while the rate of hydrogen evolution decreases with increase in light intensity (2.5-6.0-10(3) erg-cm(-2)-sec(-1)). In the presence of DCMU (10(-5)-10(-4) M), hydrogen evolution is not inhibited in the presence of pyruvate or formiate and is inhibited to a less extent in the presence of glucose. According to the results obtained, hydrogen evolution by A. variabilis in the light does not require the action of two photosystems. Inhibition of hydrogen production at significant light intensities is due to the action of oxygen on this process; the rate of oxygen evolution increases with light intensity.

  13. Peptide-Induced AIEgen Self-Assembly: A New Strategy to Realize Highly Sensitive Fluorescent Light-Up Probes.

    PubMed

    Han, Aitian; Wang, Huaimin; Kwok, Ryan T K; Ji, Shenglu; Li, Jun; Kong, Deling; Tang, Ben Zhong; Liu, Bin; Yang, Zhimou; Ding, Dan

    2016-04-05

    Fluorescent light-up probes with aggregation-induced emission (AIE) characteristics have recently attracted great research interest due to their intelligent fluorescence activation mechanism and excellent photobleaching resistance. In this work, we report a new, simple, and generic strategy to design and prepare highly sensitive AIE fluorescent light-up bioprobe through facile incorporation of a self-assembling peptide sequence GFFY between the recognition element and the AIE luminogen (AIEgen). After the bioprobes respond to the targets, the peptide GFFY is capable of inducing the ordered self-assembly of AIEgens, yielding close and tight intermolecular steric interactions to restrict the intramolecular motions of AIEgens for excellent signal output. Using two proof-of-concepts, we have demonstrated that self-assembling peptide-incorporating AIE light-up probes show much higher sensitivity in sensing the corresponding targets in both solutions and cancer cells as compared to those without GFFY induced self-assembly. Taking the probe TPE-GFFYK(DVEDEE-Ac), for example, a detection limit as low as 0.54 pM can be achieved for TPE-GFFYK(DVEDEE-Ac) in caspase-3 detection, which is much lower than that of TPE-K(DVED-Ac) (3.50 pM). This study may inspire new insights into the design of advanced fluorescent molecular probes.

  14. High-Fidelity Modelling Methodology of Light-Limited Photosynthetic Production in Microalgae.

    PubMed

    Bernardi, Andrea; Nikolaou, Andreas; Meneghesso, Andrea; Morosinotto, Tomas; Chachuat, Benoît; Bezzo, Fabrizio

    2016-01-01

    Reliable quantitative description of light-limited growth in microalgae is key to improving the design and operation of industrial production systems. This article shows how the capability to predict photosynthetic processes can benefit from a synergy between mathematical modelling and lab-scale experiments using systematic design of experiment techniques. A model of chlorophyll fluorescence developed by the authors [Nikolaou et al., J Biotechnol 194:91-99, 2015] is used as starting point, whereby the representation of non-photochemical-quenching (NPQ) process is refined for biological consistency. This model spans multiple time scales ranging from milliseconds to hours, thus calling for a combination of various experimental techniques in order to arrive at a sufficiently rich data set and determine statistically meaningful estimates for the model parameters. The methodology is demonstrated for the microalga Nannochloropsis gaditana by combining pulse amplitude modulation (PAM) fluorescence, photosynthesis rate and antenna size measurements. The results show that the calibrated model is capable of accurate quantitative predictions under a wide range of transient light conditions. Moreover, this work provides an experimental validation of the link between fluorescence and photosynthesis-irradiance (PI) curves which had been theoricized.

  15. High-Fidelity Modelling Methodology of Light-Limited Photosynthetic Production in Microalgae

    PubMed Central

    Meneghesso, Andrea; Morosinotto, Tomas; Chachuat, Benoît; Bezzo, Fabrizio

    2016-01-01

    Reliable quantitative description of light-limited growth in microalgae is key to improving the design and operation of industrial production systems. This article shows how the capability to predict photosynthetic processes can benefit from a synergy between mathematical modelling and lab-scale experiments using systematic design of experiment techniques. A model of chlorophyll fluorescence developed by the authors [Nikolaou et al., J Biotechnol 194:91–99, 2015] is used as starting point, whereby the representation of non-photochemical-quenching (NPQ) process is refined for biological consistency. This model spans multiple time scales ranging from milliseconds to hours, thus calling for a combination of various experimental techniques in order to arrive at a sufficiently rich data set and determine statistically meaningful estimates for the model parameters. The methodology is demonstrated for the microalga Nannochloropsis gaditana by combining pulse amplitude modulation (PAM) fluorescence, photosynthesis rate and antenna size measurements. The results show that the calibrated model is capable of accurate quantitative predictions under a wide range of transient light conditions. Moreover, this work provides an experimental validation of the link between fluorescence and photosynthesis-irradiance (PI) curves which had been theoricized. PMID:27055271

  16. Making genes green: creating green fluorescent protein (GFP) fusions with blunt-end PCR products.

    PubMed

    Lo, W; Rodgers, W; Hughes, T

    1998-07-01

    The jellyfish green fluorescent protein (GFP) has proven to be a useful tool in protein localization and trafficking studies. Fused to GFP, a protein of interest can be visualized and tracked in vivo through fluorescence microscopy. However, the process of making these fusion proteins is often tedious and painstaking. Here, we describe a simple and quick method for creating GFP fusion proteins using blunt-end PCR product ligation.

  17. Field-induced control of universal fluorescence intermittency of a quantum dot light emitter

    NASA Astrophysics Data System (ADS)

    Lee, J. D.; Maenosono, S.

    2010-08-01

    With the nonstochastic quantum mechanical study of a quantum dot light emitter, we find that fluorescence intermittency statistics are universal and insensitive to the microscopic nature of the tunneling fluctuation between quantum dot and trapping state. We also investigate the power-law exponent θ and the crossover time τC of the on-time (τon) probability P(τon)∝τon-θ (for τon≲τC) and ∝e-Γτon (for τon≳τC) under an optical field of given energy and strength. For easy off-resonance excitation, it is found in both numerical and analytic ways that τC-1 is proportional to the intensity of the optical field (i.e., the square of the field strength) independent of the internal parameters of a quantum dot. Furthermore, it is also found that θ =2 in the limit of vanishing field strength is the upper bound of the exponent and θ becomes less than 2 as the field strength increases.

  18. Compact fluorescent lights and the impact of convenience and knowledge on household recycling rates.

    PubMed

    Wagner, Travis P

    2011-06-01

    Increased energy costs, social marketing campaigns, public subsidies, and reduced retail prices have dramatically increased the number of compact fluorescent lights (CFLs) installed worldwide. CFLs provide many benefits, but they contain a very small amount of mercury. Given the billions of CFLs in use worldwide, they represent a significant source of mercury unless CFLs are recycled and the mercury recovered in an environmentally sound manner. In the state of Maine (northeast United States), despite mandated recycling of CFLs and availability of free CFL recycling, the household CFL recycling rate is very low. A study was undertaken to identify the primary factors responsible for low recycling. The first step was to survey householders who use CFLs. The 520 survey responses indicated that insufficient knowledge regarding recycling and inconvenience of the collection system are the two primary factors for the low recycling rate. To validate these findings, the second step was an examination of the current collection system to assess (a) the knowledge requirements necessary for recycling and (b) the convenience of the collection system. The results of this examination validated that knowledge requirements were excessively difficult to fulfill and the collection system is not sufficiently convenient. Based on these results, waste managers should focus on increasing convenience and simplifying access to information when designing or improving household collection and recycling of CFLs.

  19. Multicolor fluorescent light-emitting diodes based on cesium lead halide perovskite quantum dots

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Bai, Xue; Sun, Chun; Zhang, Xiaoyu; Zhang, Tieqiang; Zhang, Yu

    2016-08-01

    High quantum yield, narrow full width at half-maximum and tunable emission color of perovskite quantum dots (QDs) make this kind of material good prospects for light-emitting diodes (LEDs). However, the relatively poor stability under high temperature and air condition limits the device performance. To overcome this issue, the liquid-type packaging structure in combination with blue LED chip was employed to fabricate the fluorescent perovskite quantum dot-based LEDs. A variety of monochromatic LEDs with green, yellow, reddish-orange, and red emission were fabricated by utilizing the inorganic cesium lead halide perovskite quantum dots as the color-conversion layer, which exhibited the narrow full width at half-maximum (<35 nm), the relatively high luminous efficiency (reaching 75.5 lm/W), and the relatively high external quantum efficiency (14.6%), making it the best-performing perovskite LEDs so far. Compared to the solid state LED device, the liquid-type LED devices exhibited excellent color stability against the various working currents. Furthermore, we demonstrated the potential prospects of all-inorganic perovskite QDs for the liquid-type warm white LEDs.

  20. Effects of a Fluorescent Myosin Light Chain Phosphatase Inhibitor on Prostate Cancer Cells

    PubMed Central

    Grindrod, Scott; Suy, Simeng; Fallen, Shannon; Eto, Masumi; Toretsky, Jeffrey; Brown, Milton L.

    2011-01-01

    Myosin light chain phosphatase (MLCP) is an enzyme important to regulation of cell cycle and motility that is shown to be upregulated in aggressive prostate cancer cells and tissue. We developed a fluorescent small molecule inhibitor of MLCP using structure based design in recombinant protein phosphatase 1C. Several best fit compounds were synthesized and evaluated by their inhibition of MLCP/32P-MLC dephosphorylation, which resulted in the identification of novel MLCP inhibitors. Androgen dependent (AD) and castration resistant prostate cancer cell (CRPC) lines were treated with the lead inhibitor resulting in decreased growth rate, reduced DNA synthesis, and G2/M cell cycle arrest. Moreover, CRPC cell lines showed an increased sensitivity to drug treatment having GI50 values four times lower than the AD prostate cancer cell line. This was reinforced by reduced BrdU DNA incorporation into CRPC cells compared to AD cells. β-actin disruption was also seen at much lower drug concentrations in CR cells which caused a dose dependent reduction in cellular chemotaxis of PC-3 cells. Since there are currently few clinical therapeutics targeting CR prostate cancer, MLCP represents a new target for preclinical and clinical development of new potential therapeutics which inhibit this disease phenotype. PMID:22655237

  1. [Theoretical study of fluorescence of photosynthetic pigments at complex dependence of intensity of exciting light on time].

    PubMed

    Alekseev, A A; Belov, A A; Kirzhanov, D V; Kukushkin, A K

    2012-01-01

    Now the methods using the radiance with complex dependence of light intensity on time are applied to research of photosynthesis by means of fluorescence, exciting photosynthetic pigments. One of these methods is applied in PAM-fluorometers--the commercial devices currently widely used to investigate a state of photosynthesizing systems. However, if excitation is performed in this way, the question, what components of fluorescence are registered at an output of such devices, remains to be open-ended. In this work an attempt to analyse this task has been made.

  2. Light dose versus rate of delivery: implications for macroalgal productivity.

    PubMed

    Desmond, Matthew J; Pritchard, Daniel W; Hepburn, Christopher D

    2017-04-07

    The role of how light is delivered over time is an area of macroalgal photosynthesis that has been overlooked but may play a significant role in controlling rates of productivity and the structure and persistence of communities. Here we present data that quantify the relative influence of total quantum dose and delivery rate on the photosynthetic productivity of five ecologically important Phaeophyceae species from southern New Zealand. Results suggested that greater net oxygen production occurs when light is delivered at a lower photon flux density (PFD) over a longer period compared to a greater PFD over a shorter period, given the same total dose. This was due to greater efficiency (α) at a lower PFD which, for some species, meant a compensatory effect can occur. This resulted in equal or greater productivity even when the total quantum dose of the lower PFD was significantly reduced. It was also shown that light limitation at Huriawa Peninsula, where macroaglae were sourced, may be restricting the acclimation potential of species at greater depths, and that even at shallow depth periods of significant light limitation are likely to occur. This research is of particular interest as the variability of light delivery to coastal reef systems increases as a result of anthropogenic disturbances, and as the value of in situ community primary productivity estimates is recognised.

  3. Acclimation of shade-tolerant and light-resistant Tradescantia species to growth light: chlorophyll a fluorescence, electron transport, and xanthophyll content.

    PubMed

    Mishanin, Vladimir I; Trubitsin, Boris V; Patsaeva, Svetlana V; Ptushenko, Vasily V; Solovchenko, Alexei E; Tikhonov, Alexander N

    2017-02-08

    In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m(-2) s(-1)) or high light (HL, 875-1000 µmol photons m(-2) s(-1)) conditions during their entire growth period. For monitoring the functional state of photosynthetic apparatus (PSA), we measured chlorophyll (Chl) a emission fluorescence spectra and kinetics of light-induced changes in the heights of fluorescence peaks at 685 and 740 nm (F 685 and F 740). We also compared the light-induced oxidation of P700 and assayed the composition of carotenoids in Tradescantia leaves grown under the LL and HL conditions. The analyses of slow induction of Chl a fluorescence (SIF) uncovered different traits in the LL- and HL-grown plants of ecologically contrasting Tradescantia species, which may have potential ecophysiological significance with respect to their tolerance to HL stress. The fluorometry and EPR studies of induction events in chloroplasts in situ demonstrated that acclimation of both Tradescantia species to HL conditions promoted faster responses of their PSA as compared to LL-grown plants. Acclimation of both species to HL also caused marked changes in the leaf anatomy and carotenoid composition (an increase in Violaxanthin + Antheraxantin + Zeaxanthin and Lutein pools), suggesting enhanced photoprotective capacity of the carotenoids in the plants grown in nature under high irradiance. Collectively, the results of the present work suggest that the mechanisms of long-term PSA photoprotection in Tradescantia are based predominantly on the light-induced remodeling of pigment-protein complexes in chloroplasts.

  4. Detection of silver nanoparticles in cells by flow cytometry using light scatter and far-red fluorescence.

    PubMed

    Zucker, R M; Daniel, K M; Massaro, E J; Karafas, S J; Degn, L L; Boyes, W K

    2013-10-01

    The cellular uptake of different sized silver nanoparticles (AgNP) (10, 50, and 75 nm) coated with polyvinylpyrrolidone (PVP) or citrate on a human derived retinal pigment epithelial cell line (ARPE-19) was detected by flow cytometry following 24-h incubation of the cells with AgNP. A dose dependent increase of side scatter and far red fluorescence was observed with both PVP and citrate-coated 50 nm or 75 nm silver particles. Using five different flow cytometers, a far red fluorescence signal in the 700-800 nm range increased as much as 100 times background as a ratio comparing the intensity measurements of treated sample and controls. The citrate-coated silver nanoparticles (AgNP) revealed slightly more side scatter and far red fluorescence than did the PVP coated silver nanoparticles. This increased far red fluorescence signal was observed with 50 and 75 nm particles, but not with 10 nm particles. Morphological evaluation by dark field microscopy showed silver particles (50 and 75 nm) clumped and concentrated around the nucleus. One possible hypothesis to explain the emission of far red fluorescence from cells incubated with silver nanoparticles is that the silver nanoparticles inside cells agglomerate into small nano clusters that form surface plasmon resonance which interacts with laser light to emit a strong far red fluorescence signal. The results demonstrate that two different parameters (side scatter and far red fluorescence) on standard flow cytometers can be used to detect and observe metallic nanoparticles inside cells. The strength of the far red fluorescence suggests that it may be particularly useful for applications that require high sensitivity. © Published 2013 Wiley-Periodicals, Inc.

  5. Levels of Visual Stress in Proficient Readers: Effects of Spectral Filtering of Fluorescent Lighting on Reading Discomfort.

    PubMed

    Loew, Stephen J; Rodríguez, Celestino; Marsh, Nigel V; Jones, Graham L; Núñez, Jose Carlos; Watson, Kenneth

    2015-08-10

    Visual stress (VS) affects reading in 5-12% of the general population and 31-36% of children with reading disorders. Symptoms include print distortions and visual discomfort when reading, and are exacerbated by fluorescent lighting. Prior research has indicated that VS can also affect proficient readers. We therefore examined levels of visual discomfort in a group of expert readers (n = 24) under both standard and spectrally-filtered fluorescent lighting. Participants rated their awareness of six symptoms of VS under each lighting condition. Under the standard condition, 4(16.7%) of the group recorded moderate to high levels of VS. Differences in symptom levels and reading speed between conditions were analysed using the Wilcoxon Signed Rank Test. Under the filter condition, the group reported less discomfort regarding all six symptoms of VS surveyed. The differences were significant with respect to three of the symptoms (p = .029 - p < .001), with a medium effect size in all of them (r = .31 - r = .46) and total score (p = .007; r = .39). Variations in reading proficiency included significantly fewer self-corrections (p = .019) and total errors (p = .004). Here we present evidence that VS-type symptoms of reading discomfort are not confined to populations with reading difficulties and may also occur in proficient readers, and that simple adaptations to fluorescent lighting may alleviate such symptoms.

  6. Product Quality Assurance for Off-Grid Lighting in Africa

    SciTech Connect

    World Bank; Mills, Evan; Mills, Evan

    2008-07-13

    Although the emergence of markets for high efficiency off-grid lighting technologies holds promise, realizing the potential of this opportunity on a long-term, sustainable basis requires careful attention to issues of product quality, consumer protection, and the potential for significant 'market spoiling', in anticipation of increases of sales of low cost, low performance off-grid lighting products. The goal of the Lighting Africa quality assurance workshop was to articulate strategies to mitigate the dangers of market spoiling and to explore ways to protect consumers from misleading advertising for sales of inferior, off-grid lighting products in the context of Lighting Africa's overarching objective to support the industry in developing a robust off-grid lighting market in Africa. The workshop resulted in the identification of two strategic approaches for meeting Lighting Africa quality assurance programmatic needs. The first strategy is intended to meet a short-term programmatic need for quality associated with requests for lighting products by bulk procurement agents, such as in a World Bank-financed project. The development of procurement specifications and test procedures that could be used in a quality/usability screening method in order to provide guidance for forthcoming large volume purchases emerged as the best solution to meet this need. Such approaches are used in World Bank-financed solar home systems (SHSs) projects in Bangladesh, Sri Lanka, and China, among others. However, unlike the SHSs which have multiple balance-of-system (BOS) components warranting the need for an array of specifications for individual components, stand alone lighting systems require specifications that are amenable to individual light points. To test this approach, Lighting Africa elected to use the technical specifications issued by the Photovoltaic Global Approval Program for solar lanterns that use CFL bulbs (PVRS11A) as the basis of qualifying such products. A contract

  7. Effect of Triplet Harvesting on the Lifetime Based on Fluorescence and Phosphorescence in Hybrid White Organic Light Emitting Diodes.

    PubMed

    Lee, Eun; Lee, Ho Won; Yang, Hyung Jin; Sun, Yong; Lee, Jae Woo; Hwang, Kyo Min; Kim, Woo Young; Kim, Young Kwan

    2016-03-01

    We investigated efficient hybrid white organic light emitting diodes (WOLEDs) apply to triplet harvesting (TH) concept based on three complementary colors by mixing containing blue fluorescent emitter with phosphorescent emitters. The TH is to transfer these triplet excitons from a fluorescence to a phosphorescence, where they can decay radiatively. We fabricated several hybrid WOLEDs, having various emitting layer structures with blue fluorescent emitter and red, green phosphorescent emitter. The WOLED exhibited maximum luminous efficiency of 9.02 cd/A, and a maximum external quantum efficiency of 4.17%. The WOLED showed a highly color-stable white emission with the Commission International de L'Éclairage chromaticity of (0.38, 0.36) at 1,000 cd/m2.

  8. Clinical comparison of the pharmacokinetics of m-THPC and Photofrin II as observed by light-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Braichotte, Daniel; Savary, Jean-Francois; Wagnieres, Georges A.; Mudry, A.; Fontolliet, Charlotte; Monnier, Philippe; van den Bergh, Hubert

    1994-01-01

    To optimize phototherapy and photodetection of cancer, one of the important variables is the localization of the dye after injection. To study this in a clinical context, we have constructed an apparatus based on a non-invasive optical fiber that detects the dye by light induced fluorescence. The time course of the fluorescence signal can be used directly for optimizing photodetection. However, complementary information on the detailed localization of the drug by fluorescence microscopy, and a correlation of this data with tumor necrosis efficacy, are necessary to optimize PDT timing. This will be demonstrated for the case of Photofrin II and tetra (meta- hydroxyphenyl) chlorin (mTHPC) and the two sets of data will be compared.

  9. Optimization of light use efficiency for biofuel production in algae.

    PubMed

    Simionato, Diana; Basso, Stefania; Giacometti, Giorgio M; Morosinotto, Tomas

    2013-12-01

    A major challenge for next decades is development of competitive renewable energy sources, highly needed to compensate fossil fuels reserves and reduce greenhouse gas emissions. Among different possibilities, which are currently under investigation, there is the exploitation of unicellular algae for production of biofuels and biodiesel in particular. Some algae species have the ability of accumulating large amount of lipids within their cells which can be exploited as feedstock for the production of biodiesel. Strong research efforts are however still needed to fulfill this potential and optimize cultivation systems and biomass harvesting. Light provides the energy supporting algae growth and available radiation must be exploited with the highest possible efficiency to optimize productivity and make microalgae large scale cultivation energetically and economically sustainable. Investigation of the molecular bases influencing light use efficiency is thus seminal for the success of this biotechnology. In this work factors influencing light use efficiency in algal biomass production are reviewed, focusing on how algae genetic engineering and control of light environment within photobioreactors can improve the productivity of large scale cultivation systems.

  10. Effect of ambient light on IgG1 monoclonal antibodies during drug product processing and development.

    PubMed

    Sreedhara, Alavattam; Yin, Jian; Joyce, Michael; Lau, Kimberly; Wecksler, Aaron T; Deperalta, Galahad; Yi, Li; John Wang, Y; Kabakoff, Bruce; Kishore, Ravuri S K

    2016-03-01

    Photostability studies are standard stress testing conducted during drug product development of various pharmaceutical compounds, including small molecules and proteins. These studies as recommended by ICH Q1B are carried out using no less than 1.2× 10(6)lux-hours in the visible region and no less than 200Wh/m(2) in UV light. However, normal drug product processing is carried out under fluorescent lamps that emit white light almost exclusively in the >400nm region with a small UV quotient. We term these as ambient or mild light conditions. We tested several IgG1 monoclonal antibodies (mAbs 1-5) under these ambient light conditions and compared them to the ICH light conditions. All the mAbs were significantly degraded under the ICH light but several mAbs (mAbs 3-5) were processed without impacting any product quality attributes under ambient or mild light conditions. Interestingly we observed site-specific Trp oxidation in mAb1, while higher aggregation and color change were observed for mAb2 under mild light conditions. The recommended ICH light conditions have a high UV component and hence may not help to rank order photosensitivity under normal protein DP processing conditions.

  11. Research of fluorescent spectra of oleic acid-stabilized ZnSe nanocrystals based on UV light modification

    NASA Astrophysics Data System (ADS)

    Hao, Licai; Bai, Zhongchen; Huang, Zhaoliang; Liao, Sha; Zhang, Zhengping

    2016-11-01

    The non-aqueous synthesized and post-preparative treatment of oleic acid (OA)-stabilized ZnSe nanocrystals were studied systematically. ZnSe nanocrystals were successfully synthesized via paraffin liquid and oleic acid system by using OA as stabilizer. Synthesized nanocrystals were characterized by means of absorption and fluorescent spectra, Fourier transform infrared spectrometer, transmission electron microscopy and selected area electron diffraction. Furthermore, solutions of ZnSe nanocrystals were illuminated with UV light. The experimental results showed that the fluorescent peak was red-shifted from 445 to 510 nm. The results suggested that, when the solution under illumination, OA was removed from the surface of ZnSe nanocrystals and the surface of ZnSe nanocrystals was oxidized to ZnO nanocrystals. ZnSe/ZnO core/shell nanocrystals were formed when the solution of ZnSe nanocrystals illuminated with UV light.

  12. Light-emitting diode fluorescence microscopy for tuberculosis diagnosis: a meta-analysis.

    PubMed

    Chang, Eva W; Page, Anne-Laure; Bonnet, Maryline

    2016-03-01

    Light-emitting diode fluorescence microscopy (LED-FM) is recommended by the World Health Organization to replace conventional Ziehl-Neelsen microscopy for pulmonary tuberculosis diagnosis. Uptake of LED-FM has been slow. One reason is its reported loss of specificity compared with Ziehl-Neelsen microscopy. We aimed to determine the diagnostic accuracy of LED-FM for tuberculosis detection and explore potential factors that might affect its performance.A comprehensive search strategy based on pre-specified criteria was employed to identify eligible studies between January 1, 2000 and April 1, 2014 in 11 databases. Standardised study selection, data extraction and quality assessment were conducted. Pooled sensitivity and specificity of LED-FM using culture as the reference standard were estimated through meta-analyses using a bivariate random-effects model. Investigation of heterogeneity was performed by subgroup analyses.We identified 12 unique studies, half of which were from peripheral healthcare facilities. LED-FM achieved a pooled sensitivity of 66.9% (95% CI 60.5-72.7%) and pooled specificity of 96.8% (95% CI 93.1-98.6%). A pooled sensitivity of 53.0% (95% CI 42.8-63.0%) and pooled specificity of 96.1% (95% CI 86.0-99.0%) were obtained by LED-FM among HIV-infected patients. Study methodology factors and differences in the LED-FM procedure or device could also affect the performance.LED-FM specificity is high and should not be a barrier to device introduction, particularly among peripheral healthcare settings where this technology is meant to be used. Sensitivity is reduced in HIV-infected patients.

  13. Relationships between human cataracts and environmental radiant energy. Cataract formation, light scattering and fluorescence.

    PubMed

    Zigman, S; Sutliff, G; Rounds, M

    1991-01-01

    This preliminary report has two parts. The first is based upon data obtained from a group of cataract patients in southern Florida (USA) with the object of relating the types of cataracts removed to their personal background and their protein biochemistry. Intra-capsular cataract surgery patients at the Venice Eye Clinic (Florida) were interviewed, and their extracted lenses were classified. The parameters were: age, place of residency, occupation, medical and family history and indoor/outdoor activity. Subcapsular cataracts were found mainly in the youngest patients and in those who were in Florida the least. Mixed cataracts predominated in the oldest patients, while non-nuclear cataracts were associated most with outdoor activity. Water-insoluble protein was elevated in nuclei of lenses with nuclear opacities. Soluble proteins in the nuclei of nuclear cataracts had increased levels of voided (heavy) protein, beta-crystallins, and less than 20 Kd peptides. The above changes were enhanced in brunescent cataracts. In lenses with cortical opacities, only increased size heterogeneity in the beta-crystallin region was observed. The second part of this report is based upon direct measurements of the optical properties of freshly extracted intra-capsular cataracts obtained in Rochester, New York (USA). The purpose was to attempt to learn the relative contributions that absorption, scattering, and fluorescence make toward obscuring vision. A general conclusion is that the shorter wavelengths of radiant energy in environmental lighting influence the above-stated optical properties the most, and thus appear to be the major contributors to obscured vision.

  14. Bimane: A Visible Light Induced Fluorescent Photoremovable Protecting Group for the Single and Dual Release of Carboxylic and Amino Acids.

    PubMed

    Chaudhuri, Amrita; Venkatesh, Yarra; Behara, Krishna Kalyani; Singh, N D Pradeep

    2017-03-10

    A series of ester conjugates of carboxylic and amino acids were synthesized based on bimane fluorescent photoremovable protecting group (FPRPG). The photorelease of single and dual (same as well as different) carboxylic and amino acids is demonstrated from a single bimane molecule on irradiation with visible light (λ ≥ 410 nm). The detailed mechanistic study of photorelease revealed that the release of two caged acids is simultaneous but in a stepwise pathway.

  15. Hadron production in light and heavy, quark and antiquark jets

    SciTech Connect

    Baird, K.G.; SLD Collaboration

    1996-08-01

    The authors review four hadronization studies performed by the SLD experiment at SLAC, involving separation of light (Z{sup 0} {r_arrow} u{anti u}, d{anti d}, s{anti s}), c, and b flavors using precision vertexing, and separation of q- and {anti q}-jets using the highly polarized SLC electron beam. They measured the differences between the average charged multiplicities in Z{sup 0} {r_arrow} light, {r_arrow} c{anti c}, and {r_arrow}b{anti b} events, and found that the results were consistent with predictions of perturbative QCD. Next, they measured {pi}/{Kappa}/p/{Kappa}{sup 0}/{Lambda}{sup 0} production in light events for the first time, and compared with production in c- and b-flavor events. They then examined particle production differences in light quark and antiquark hemispheres, and observed more high momentum baryons and K{sup {minus}}`s than antibaryons and K{sup +}`s in quark hemispheres, consistent with the leading particle hypothesis. Lastly, they performed a search for jet handedness in light q- and {anti q}-jets. Assuming Standard Model values of quark polarization in Z{sup 0} decays, they have set an improved upper limit on the analyzing power of the handedness method.

  16. Nanosecond ratio imaging of redox states in tumor cell spheroids using light sheet-based fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Schickinger, Sarah; Bruns, Thomas; Wittig, Rainer; Weber, Petra; Wagner, Michael; Schneckenburger, Herbert

    2013-12-01

    A new concept of three-dimensional imaging of tumor cell spheroids by light sheet-based fluorescence microscopy and nanosecond ratio imaging is described. Due to its low light dose and alternative excitation by two laser wavelengths (391 and 470 nm), this method maintains cell viability and permits recording of real-time kinetics. A genetically encoded sensor permits measurement of the redox state of glutathione and visualization of the impact of oxygen radicals. The pharmaceutically relevant system is tested upon addition of an oxidizing agent (H2O2), as well as upon addition of the apoptosis-inducing agent staurosporine.

  17. Perturbation by UV Light for Rapid Classification of Biological Particles by Fluorescence

    DTIC Science & Technology

    2007-01-01

    27 5 FIGURES 1. Fluorescence of two isogenic Bacillus subtilis spore samples (DPA- and DPA+) before...Ex-Em graphs for E. coli grown overnight in rich medium ............................. 15 4. Bacillus thuringiensis spores ...from the chemical as a spore component. These were followed by studies of the Ex-Em graph of Bacillus subtilis spores of two types: The fluorescence Ex

  18. LED-FISH: Fluorescence microscopy based on light emitting diodes for the molecular analysis of Her-2/neu oncogene amplification.

    PubMed

    Lang, Dagmar S; Zeiser, Tobias; Schultz, Holger; Stellmacher, Florian; Vollmer, Ekkehard; Zabel, Peter; Goldmann, Torsten

    2008-12-16

    Light emitting diodes (LED), which are available as small monochromatic light sources with characteristic features such as maximum illumination power combined with minimum energy consumption and extremely long lifespan have already proved as a highly potential low-cost alternative for specific diagnostic applications in clinical medicine such as tuberculosis fluorescence microscopy. Likewise, the most reliable evaluation of Her-2/neu (c-erbB2) gene amplification, which has been established in the last few years for routine diagnosis in clinical pathology as determinant towards Herceptin-based treatment of patients with breast cancer, is based on fluorescence in situ hybridization (FISH) and corresponding high priced fluorescence equipment. In order to test the possibility to utilize the advantages of low-cost LED technology on FISH analysis of c-erbB2 gene expression for routine diagnostic purposes, the applicability of a standard bright field Carl Zeiss Axiostar Plus microscope equipped with a Fraen AFTER (Amplified Fluorescence by Transmitted Excitation of Radiation) LED Fluorescence Microscope Kit for the detection of Her-2/neu gene signals was compared to an advanced Nikon Eclipse 80i fluorescence microscope in combination with a conventional 100W mercury vapor lamp. Both microscopes were fitted with the same Quicam FAST CCD digital camera to unequivocally compare the quality of the captured images. C-erbB2 gene expression was analyzed in 30 different human tissue samples of primary invasive breast cancer, following formalin fixation and subsequent paraffin-embedding. The Her2/neu gene signals (green) were identifiable in the tumor cells in all cases and images of equal quality were captured under almost identical conditions by 480 nm (blue) LED module equipped standard Axiostar microscope as compared to conventional fluorescence microscopy. In this first attempt, these monochromatic LED elements proved in principle to be suitable for the detection of Her-2/neu

  19. Review of organic light-emitting diodes with thermally activated delayed fluorescence emitters for energy-efficient sustainable light sources and displays

    NASA Astrophysics Data System (ADS)

    Volz, Daniel

    2016-04-01

    Thermally activated delayed fluorescence (TADF) is an emerging hot topic. Even though this photophysical mechanism itself has been described more than 50 years ago and optoelectronic devices with organic matter have been studied, improved, and even commercialized for decades now, the realization of the potential of TADF organic light-emitting diodes (OLEDs) happened only recently. TADF has been proven to be an attractive and very efficient alternative for phosphorescent materials, such as dopants in OLEDs, light-emitting electrochemical cells as well as potent emitters for chemiluminescence. In this review, the TADF concept is introduced in terms that are also understandable for nonchemists. The basic concepts behind this mechanism as well as state-of-the-art examples are discussed. In addition, the future economic impact, especially for the lighting and display market, is addressed here. We conclude that TADF materials are especially helpful to realize efficient, durable deep blue and white displays.

  20. Light Element Production in Type Ib/c Supernovae

    SciTech Connect

    Nakamura, Ko

    2008-05-21

    Recent observations of halo stars indicate non-primordial {sup 6}Li and Be, which are produced through cosmic-ray interactions. Some energetic supernovae can accelerate particles to energies enough to interact with ambient material and produce light elements including {sup 6}Li and {sup 9}Be. We investigate interactions between Type Ib/c supernova ejecta and the circumstellar matter (CSM) as production sites for the light elements, particularly {sup 6}Li and {sup 9}Be in the early stages of the Galactic chemical evolution. Considered are energetic Type Ib/c supernova explosions of Wolf-Rayet type stars at low metallicities, embedded in the dense CSM. The energetic portion of the supernova ejecta can interact directly with the circumstellar material and induce light-element production via spallation and {alpha}-{alpha} fusion reactions. We find that accelerated particles lose their energy through Coulomb collisions with free electrons near the stellar surface where very dense CSM resides, so that most of light elements are produced at the near-surface region. This fact suggests that the amounts of produced light elements and their ratios strongly depend on the chemical compositions of the region. The resulting {sup 6}Li and {sup 9}Be abundances in the ejecta and the cicumstellar material out of which very metal-poor stars form may show scattering, though it has not yet been confirmed.

  1. Multi-scale analyses reveal robust relations between solar induced fluorescence and gross primary production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remotely sensed solar induced fluorescence (SIF) has shown great promise for probing spatiotemporal variations in terrestrial gross primary production (GPP), the largest component flux of the global carbon cycle. However, scale mismatches between SIF and ground-based GPP have posed challenges toward...

  2. Fluorescence formation from the interaction of DNA with lipid oxidation degradation products.

    PubMed

    Frankel, E N; Neff, W E; Brooks, D D; Fujimoto, K

    1987-06-23

    To clarify the mechanism of fluorescence formation between DNA and lipid degradation products in the presence of ferric chloride and ascorbic acid, a number of carbonyl compounds and decomposition products of pure methyl linolenate hydroperoxides were examined. Keto derivatives of methyl ricinoleate, linoleate, and oleate, alkanals and 2-alkenals produced little or no fluorescence with DNA in the presence of ferric chloride-ascorbic acid. 2,4-Alkadienals were more active and 2,4,7-decatrienal was the most active. Mixtures of volatile aldehydes prepared from linolenate hydroperoxide decomposed either thermally or with iron and ascorbate had the same activity as 2,4,7-decatrienal. Higher molecular-weight products from the decomposition of methyl linolenate hydroperoxides showed relatively low activity. beta-Carotene, alpha-tocopherol and other antioxidants effectively reduced the amount of fluorescence formed by linolenate hydroperoxides. The results suggest that, in addition to hydroperoxide decomposition products, singlet oxygen and/or free radical species contribute significantly to the fluorescence formed from the interaction of methyl linolenate hydroperoxides with DNA in the presence of ferric chloride and ascorbic acid.

  3. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence.

    PubMed

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A; Guanter, Luis; Boyce, C Kevin; Fisher, Joshua B; Morrow, Eric; Worden, John R; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-06-22

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.

  4. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence

    PubMed Central

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A.; Guanter, Luis; Boyce, C. Kevin; Fisher, Joshua B.; Morrow, Eric; Worden, John R.; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-01-01

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r2 = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r2 = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009. PMID:23760636

  5. Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

    PubMed

    Hazrati, Saeid; Tahmasebi-Sarvestani, Zeinolabedin; Modarres-Sanavy, Seyed Ali Mohammad; Mokhtassi-Bidgoli, Ali; Nicola, Silvana

    2016-09-01

    Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments.

  6. Effect of light-emitting diode (LED) vs. fluorescent (FL) lighting on laying hens in aviary hen houses: Part 2 - Egg quality, shelf-life and lipid composition.

    PubMed

    Long, H; Zhao, Y; Xin, H; Hansen, H; Ning, Z; Wang, T

    2016-01-01

    In this 60-wk study, egg quality, egg shelf-life, egg cholesterol content, total yolk lipids, and yolk fatty acid composition of eggs produced by Dekalb white laying hens in commercial aviary houses with either light-emitting diode (LED) or fluorescent (FL) lighting were compared. All parameters were measured at 27, 40, and 60 wk of age, except for egg shelf-life, which was compared at 50 wk of age. The results showed that, compared to the FL regimen, the LED regimen resulted in higher egg weight, albumen height, and albumen weight at 27 wk of age, thicker shells at 40 wk of age, but lower egg weight at 60 wk of age. Egg quality change was similar between the lighting regimens during the 62-d egg storage study, indicating that LED lighting did not influence egg shelf-life. Eggs from both lighting regimens had similar cholesterol content. However, cholesterol concentration of the yolk (15.9 to 21.0 mg cholesterol/g wet weight yolk) observed in this study was higher than that of United States Department of Agriculture (USDA) database (10.85 mg/g). No significant differences in total lipids or fatty acid composition of the yolks were detected between the two lighting regimens.

  7. PsbS is required for systemic acquired acclimation and post-excess-light-stress optimization of chlorophyll fluorescence decay times in Arabidopsis.

    PubMed

    Ciszak, Kamil; Kulasek, Milena; Barczak, Anna; Grzelak, Justyna; Maćkowski, Sebastian; Karpiński, Stanisław

    2015-01-01

    Systemic acquired acclimation (SAA) is an important light acclimatory mechanism that depends on the global adjustments of non-photochemical quenching and chloroplast retrograde signaling. As the exact regulation of these processes is not known, we measured time-resolved fluorescence of chlorophyll a in Arabidopsis thaliana leaves exposed to excess light, in leaves undergoing SAA, and in leaves after excess light episode. We compare the behavior induced in wild-type plants with null mutant of non-photochemical quenching (npq4-1). The wild type rosettes exhibit a small reduction of fluorescence decay times in leaves directly exposed to excess light and in leaves undergoing SAA in ambient low light. However in npq4-1 exposition to excess light results in much faster fluorescence decay, which is insensitive to excitation power. At the same time npq4-1 leaves undergoing SAA displayed intermediate fluorescence decay. The npq4-1 plants also lost the ability to optimize florescence decay, and thus chlorophyll a dynamics up to 2 h after excess light episode. The fluorescence decay dynamics in both WT and npq4-1 can be described by a set of 3 maximum decay times. Based on the results, we concluded that functional PsbS is required for optimization of absorbed photon fate and optimal light acclimatory responses such as SAA or after excess light stress.

  8. PsbS is required for systemic acquired acclimation and post-excess-light-stress optimization of chlorophyll fluorescence decay times in Arabidopsis

    PubMed Central

    Ciszak, Kamil; Kulasek, Milena; Barczak, Anna; Grzelak, Justyna; Maćkowski, Sebastian; Karpiński, Stanisław

    2015-01-01

    Systemic acquired acclimation (SAA) is an important light acclimatory mechanism that depends on the global adjustments of non-photochemical quenching and chloroplast retrograde signaling. As the exact regulation of these processes is not known, we measured time-resolved fluorescence of chlorophyll a in Arabidopsis thaliana leaves exposed to excess light, in leaves undergoing SAA, and in leaves after excess light episode. We compare the behavior induced in wild-type plants with null mutant of non-photochemical quenching (npq4–1). The wild type rosettes exhibit a small reduction of fluorescence decay times in leaves directly exposed to excess light and in leaves undergoing SAA in ambient low light. However in npq4–1 exposition to excess light results in much faster fluorescence decay, which is insensitive to excitation power. At the same time npq4–1 leaves undergoing SAA displayed intermediate fluorescence decay. The npq4–1 plants also lost the ability to optimize florescence decay, and thus chlorophyll a dynamics up to 2 h after excess light episode. The fluorescence decay dynamics in both WT and npq4–1 can be described by a set of 3 maximum decay times. Based on the results, we concluded that functional PsbS is required for optimization of absorbed photon fate and optimal light acclimatory responses such as SAA or after excess light stress. PMID:25654166

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

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

  10. A Review of the Reflector Compact Fluorescent Lights Technology Procurement Program: Conclusions and Results

    SciTech Connect

    Sandahl, Linda J.; Gilbride, Theresa L.; Ledbetter, Marc R.; McCullough, Jeffrey J.

    2008-05-19

    This report describes a project sponsored by the U.S. Department of Energy (DOE) and implemented by the Pacific Northwest National Laboratory (PNNL), from 2000 to 2007 to improve the performance of reflector type (R-lamp) compact fluorescent lamps (CFLs) and increase their availability throughout the United States by means of a technology development and procurement strategy. In 2000, at the request of the U.S. Department of Energy’s Emerging Technologies Program and its predecessors, the Pacific Northwest National Laboratory undertook a technology procurement seeking R-CFLs that were specifically designed for use in ICAT recessed can fixtures and that met other minimum performance criteria including minimum light output and size restrictions (to ensure they fit in standard residential recessed cans). The technology procurement included two phases. In Phase I, requests for proposals (RFPs) were issued in October 2002 and five manufacturers responded with 12 lamp models. Eight of these models met the minimum requirements and passed the 6-hour short-term test in a simulated ICAT environment. These eight models were subjected to long-term tests of 6,000 or more hours in a simulated ICAT environment. Three of these models passed the short- and long-term tests and were promoted through the program website (www.pnl.gov/rlamps), press releases, and fliers. To increase the number of qualifying models, a second RFP was issued in June 2005. In April 2007, DOE announced that 16 reflector CFL (R-CFL) models by four manufacturers had met all the minimum requirements of Phase 2 of the R-CFL Technology Innovation Competition. PNNL developed both the criteria and the test apparatus design for Elevated Temperature Life Testing (ETLT), which has been included by DOE in its draft ENERGY STAR specifications for the reflector category of CFLs. PNNL promoted the winning lamps through a program website, press releases, and fliers as well as through program partners. PNNL also helped

  11. Bili lights

    MedlinePlus

    Phototherapy for jaundice; Bilirubin - bili lights; Neonatal care - bili lights; Newborn care - bili lights ... Phototherapy involves shining fluorescent light from the bili lights on bare skin. A specific wavelength of light can break down bilirubin into a form that ...

  12. Detection and quantification of trace elements in rice and rice products using x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Foran, Kelly A.; Fleming, David E. B.

    2015-12-01

    We used X-ray fluorescence (XRF) to examine the presence of arsenic (As) and other trace elements (manganese, iron, nickel, copper, and zinc) in rice and rice products. A portable XRF analyzer was used to test samples, and amplitudes for the analyzed elements were identified in the resulting data. The detection limit of the system was sufficiently low to detect As in some rice and rice product samples.

  13. Organic Fluorescent Dyes Supported on Activated Boron Nitride: A Promising Blue Light Excited Phosphors for High-Performance White Light-Emitting Diodes

    PubMed Central

    Li, Jie; Lin, Jing; Huang, Yang; Xu, Xuewen; Liu, Zhenya; Xue, Yanming; Ding, Xiaoxia; Luo, Han; Jin, Peng; Zhang, Jun; Zou, Jin; Tang, Chengchun

    2015-01-01

    We report an effective and rare-earth free light conversion material synthesized via a facile fabrication route, in which organic fluorescent dyes, i.e. Rhodamine B (RhB) and fluorescein isothiocyanate (FITC) are embedded into activated boron nitride (αBN) to form a composite phosphor. The composite phosphor shows highly efficient Förster resonance energy transfer and greatly improved thermal stability, and can emit at broad visible wavelengths of 500–650 nm under the 466 nm blue-light excitation. By packaging of the composite phosphors and a blue light-emitting diode (LED) chip with transparent epoxy resin, white LED with excellent thermal conductivity, current stability and optical performance can be realized, i.e. a thermal conductivity of 0.36 W/mk, a Commission Internationale de 1'Eclairage color coordinates of (0.32, 0.34), and a luminous efficiency of 21.6 lm·W−1. Our research opens the door toward to the practical long-life organic fluorescent dyes-based white LEDs. PMID:25682730

  14. Simplified, rapid, and inexpensive estimation of water primary productivity based on chlorophyll fluorescence parameter Fo.

    PubMed

    Chen, Hui; Zhou, Wei; Chen, Weixian; Xie, Wei; Jiang, Liping; Liang, Qinlang; Huang, Mingjun; Wu, Zongwen; Wang, Qiang

    2017-04-01

    Primary productivity in water environment relies on the photosynthetic production of microalgae. Chlorophyll fluorescence is widely used to detect the growth status and photosynthetic efficiency of microalgae. In this study, a method was established to determine the Chl a content, cell density of microalgae, and water primary productivity by measuring chlorophyll fluorescence parameter Fo. A significant linear relationship between chlorophyll fluorescence parameter Fo and Chl a content of microalgae, as well as between Fo and cell density, was observed under pure-culture conditions. Furthermore, water samples collected from natural aquaculture ponds were used to validate the correlation between Fo and water primary productivity, which is closely related to Chl a content in water. Thus, for a given pure culture of microalgae or phytoplankton (mainly microalgae) in aquaculture ponds or other natural ponds for which the relationship between the Fo value and Chl a content or cell density could be established, Chl a content or cell density could be determined by measuring the Fo value, thereby making it possible to calculate the water primary productivity. It is believed that this method can provide a convenient way of efficiently estimating the primary productivity in natural aquaculture ponds and bringing economic value in limnetic ecology assessment, as well as in algal bloom monitoring.

  15. Dual-channel red/blue fluorescence dosimetry with broadband reflectance spectroscopic correction measures protoporphyrin IX production during photodynamic therapy of actinic keratosis

    NASA Astrophysics Data System (ADS)

    Kanick, Stephen Chad; Davis, Scott C.; Zhao, Yan; Hasan, Tayyaba; Maytin, Edward V.; Pogue, Brian W.; Chapman, M. Shane

    2014-07-01

    Dosimetry for aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) photodynamic therapy of actinic keratosis was examined with an optimized fluorescence dosimeter to measure PpIX during treatment. While insufficient PpIX generation may be an indicator of incomplete response, there exists no standardized method to quantitate PpIX production at depths in the skin during clinical treatments. In this study, a spectrometer-based point probe dosimeter system was used to sample PpIX fluorescence from superficial (blue wavelength excitation) and deeper (red wavelength excitation) tissue layers. Broadband white light spectroscopy (WLS) was used to monitor aspects of vascular physiology and inform a correction of fluorescence for the background optical properties. Measurements in tissue phantoms showed accurate recovery of blood volume fraction and reduced scattering coefficient from WLS, and a linear response of PpIX fluorescence versus concentration down to 1.95 and 250 nM for blue and red excitations, respectively. A pilot clinical study of 19 patients receiving 1-h ALA incubation before treatment showed high intrinsic variance in PpIX fluorescence with a standard deviation/mean ratio of >0.9. PpIX fluorescence was significantly higher in patients reporting higher pain levels on a visual analog scale. These pilot data suggest that patient-specific PpIX quantitation may predict outcome response.

  16. Dual-channel red/blue fluorescence dosimetry with broadband reflectance spectroscopic correction measures protoporphyrin IX production during photodynamic therapy of actinic keratosis

    PubMed Central

    Kanick, Stephen Chad; Davis, Scott C.; Zhao, Yan; Hasan, Tayyaba; Maytin, Edward V.; Pogue, Brian W.; Chapman, M. Shane

    2014-01-01

    Abstract. Dosimetry for aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) photodynamic therapy of actinic keratosis was examined with an optimized fluorescence dosimeter to measure PpIX during treatment. While insufficient PpIX generation may be an indicator of incomplete response, there exists no standardized method to quantitate PpIX production at depths in the skin during clinical treatments. In this study, a spectrometer-based point probe dosimeter system was used to sample PpIX fluorescence from superficial (blue wavelength excitation) and deeper (red wavelength excitation) tissue layers. Broadband white light spectroscopy (WLS) was used to monitor aspects of vascular physiology and inform a correction of fluorescence for the background optical properties. Measurements in tissue phantoms showed accurate recovery of blood volume fraction and reduced scattering coefficient from WLS, and a linear response of PpIX fluorescence versus concentration down to 1.95 and 250 nM for blue and red excitations, respectively. A pilot clinical study of 19 patients receiving 1-h ALA incubation before treatment showed high intrinsic variance in PpIX fluorescence with a standard deviation/mean ratio of >0.9. PpIX fluorescence was significantly higher in patients reporting higher pain levels on a visual analog scale. These pilot data suggest that patient-specific PpIX quantitation may predict outcome response. PMID:24996661

  17. Level sequence and splitting identification of closely spaced energy levels by angle-resolved analysis of fluorescence light

    NASA Astrophysics Data System (ADS)

    Wu, Z. W.; Volotka, A. V.; Surzhykov, A.; Dong, C. Z.; Fritzsche, S.

    2016-06-01

    The angular distribution and linear polarization of the fluorescence light following the resonant photoexcitation is investigated within the framework of density matrix and second-order perturbation theory. Emphasis has been placed on "signatures" for determining the level sequence and splitting of intermediate (partially) overlapping resonances, if analyzed as a function of photon energy of incident light. Detailed computations within the multiconfiguration Dirac-Fock method have been performed, especially for the 1 s22 s22 p63 s ,Ji=1 /2 +γ1→(1s22 s 2 p63 s ) 13 p3 /2,J =1 /2 ,3 /2 →1 s22 s22 p63 s ,Jf=1 /2 +γ2 photoexcitation and subsequent fluorescence emission of atomic sodium. A remarkably strong dependence of the angular distribution and linear polarization of the γ2 fluorescence emission is found upon the level sequence and splitting of the intermediate (1s22 s 2 p63 s ) 13 p3 /2,J =1 /2 ,3 /2 overlapping resonances owing to their finite lifetime (linewidth). We therefore suggest that accurate measurements of the angular distribution and linear polarization might help identify the sequence and small splittings of closely spaced energy levels, even if they cannot be spectroscopically resolved.

  18. Fluorescence imaging of microbe-containing particles shot from a two-stage Light-gas gun into an aerogel

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Yuko; Sugino, Tomohiro; Tabata, Makoto; Okudaira, Kyoko; Imai, Eichi; Yano, Hajime; Hasegawa, Sunao; Hashimoto, Hirofumi; Yabuta, Hikaru; Kobayashi, Kensei; Kawai, Hideyuki; Mita, Hajime; Yokobori, Shin-ichi; Yamagishi, Akihiko

    2014-02-01

    We have proposed an experiment (the Tanpopo mission) to capture microbes on the Japan Experimental Module of the International Space Station. An ultra low-density silica aerogel will be exposed to space for more than 1 year. After retrieving the aerogel, particle tracks and particles found in it will be visualized by fluorescence microscopy after staining it with a DNA-specific fluorescence dye. In preparation for this study, we simulated particle trapping in an aerogel so that methods could be developed to visualize the particles and their tracks. During the Tanpopo mission, particles that have an orbital velocity of ~8 km/s are expected to collide with the aerogel. To simulate these collisions, we shot Deinococcus radiodurans-containing Lucentite particles into the aerogel from a two-stage light-gas gun (acceleration 4.2 km/s). The shapes of the captured particles, and their tracks and entrance holes were recorded with a microscope/camera system for further analysis. The size distribution of the captured particles was smaller than the original distribution, suggesting that the particles had fragmented. We were able to distinguish between microbial DNA and inorganic compounds after staining the aerogel with the DNA-specific fluorescence dye SYBR green I as the fluorescence of the stained DNA and the autofluorescence of the inorganic particles decay at different rates. The developed methods are suitable to determine if microbes exist at the International Space Station altitude.

  19. Integrated fluorescence detection of labeled biomolecules using a prism-like PDMS microfluidic chip and lateral light excitation.

    PubMed

    Novo, Pedro; Chu, Virginia; Conde, João Pedro

    2014-06-21

    Microfabricated amorphous silicon photodiodes were integrated with prism-like PDMS microfluidics for the detection and quantification of fluorescence signals. The PDMS device was fabricated with optical quality surfaces and beveled sides. A 405 nm laser beam perpendicular to the lateral sides of the microfluidic device excites the fluorophores in the microchannel at an angle of 70° to the normal to the microchannel/photodiode surface. This configuration, which makes use of the total internal reflection of the excitation beam and the isotropy of the fluorescence emission, minimizes the intensity of excitation light that reaches the integrated photodetector. A difference of two orders of magnitude was achieved in the reduction of the detection noise level as compared with a normally incident excitation configuration. A limit-of-detection of 5.6 × 10(10) antibodies per square centimeter was achieved using antibodies labeled with a model organic fluorophore. Furthermore, the results using the lateral excitation scheme are in good proportionality agreement with those by fluorescence quantification using wide-field fluorescence microscopy.

  20. A Bright Fluorescent Probe for H2S Enables Analyte-Responsive, 3D Imaging in Live Zebrafish Using Light Sheet Fluorescence Microscopy

    PubMed Central

    2015-01-01

    Hydrogen sulfide (H2S) is a critical gaseous signaling molecule emerging at the center of a rich field of chemical and biological research. As our understanding of the complexity of physiological H2S in signaling pathways evolves, advanced chemical and technological investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed an azide-functionalized O-methylrhodol fluorophore, MeRho-Az, which exhibits a rapid >1000-fold fluorescence response when treated with H2S, is selective for H2S over other biological analytes, and has a detection limit of 86 nM. Additionally, the MeRho-Az scaffold is less susceptible to photoactivation than other commonly used azide-based systems, increasing its potential application in imaging experiments. To demonstrate the efficacy of this probe for H2S detection, we demonstrate the ability of MeRho-Az to detect differences in H2S levels in C6 cells and those treated with AOAA, a common inhibitor of enzymatic H2S synthesis. Expanding the use of MeRho-Az to complex and heterogeneous biological settings, we used MeRho-Az in combination with light sheet fluorescence microscopy (LSFM) to visualize H2S in the intestinal tract of live zebrafish. This application provides the first demonstration of analyte-responsive 3D imaging with LSFM, highlighting the utility of combining new probes and live imaging methods for investigating chemical signaling in complex multicellular systems. PMID:26061541

  1. A Bright Fluorescent Probe for H2S Enables Analyte-Responsive, 3D Imaging in Live Zebrafish Using Light Sheet Fluorescence Microscopy.

    PubMed

    Hammers, Matthew D; Taormina, Michael J; Cerda, Matthew M; Montoya, Leticia A; Seidenkranz, Daniel T; Parthasarathy, Raghuveer; Pluth, Michael D

    2015-08-19

    Hydrogen sulfide (H2S) is a critical gaseous signaling molecule emerging at the center of a rich field of chemical and biological research. As our understanding of the complexity of physiological H2S in signaling pathways evolves, advanced chemical and technological investigative tools are required to make sense of this interconnectivity. Toward this goal, we have developed an azide-functionalized O-methylrhodol fluorophore, MeRho-Az, which exhibits a rapid >1000-fold fluorescence response when treated with H2S, is selective for H2S over other biological analytes, and has a detection limit of 86 nM. Additionally, the MeRho-Az scaffold is less susceptible to photoactivation than other commonly used azide-based systems, increasing its potential application in imaging experiments. To demonstrate the efficacy of this probe for H2S detection, we demonstrate the ability of MeRho-Az to detect differences in H2S levels in C6 cells and those treated with AOAA, a common inhibitor of enzymatic H2S synthesis. Expanding the use of MeRho-Az to complex and heterogeneous biological settings, we used MeRho-Az in combination with light sheet fluorescence microscopy (LSFM) to visualize H2S in the intestinal tract of live zebrafish. This application provides the first demonstration of analyte-responsive 3D imaging with LSFM, highlighting the utility of combining new probes and live imaging methods for investigating chemical signaling in complex multicellular systems.

  2. Integrated Fluorescence

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret (Inventor); Gruhlke, Russell W. (Inventor)

    1998-01-01

    A detection method is integrated with a filtering method and an enhancement method to create a fluorescence sensor that can be miniaturized. The fluorescence sensor comprises a thin film geometry including a waveguide layer, a metal film layer and sensor layer. The thin film geometry of the fluorescence sensor allows the detection of fluorescent radiation over a narrow wavelength interval. This enables wavelength discrimination and eliminates the detection of unwanted light from unknown or spurious sources.

  3. National voluntary laboratory accreditation program: Energy efficient lighting products. Handbook

    SciTech Connect

    Galowin, L.S.; Hall, W.; Rossiter, W.J.

    1994-07-01

    The purpose of this handbook is to set out procedures and technical requirements for the National Voluntary Laboratory Accreditation Program (NVLAP) accreditation of laboratories which perform test methods covered by the Energy Efficient Lighting (EEL) Products program. It complements and supplements the NVLAP programmatic procedures and general requirements found in NIST Handbook 150 (PB94-178225). The interpretive comments and additional requirements contained in this handbook make the general NVLAP criteria specifically applicable to the EEL program.

  4. Development of an integrated direct-contacting optical-fiber microchip with light-emitting diode-induced fluorescence detection.

    PubMed

    Liu, Changchun; Cui, Dafu; Chen, Xing

    2007-11-02

    In this paper, one poly(dimethylsiloxane) (PDMS) sandwich microchip integrated with one direct-contacting optical fiber was fabricated by using a thin-casting method. This novel integrated PDMS sandwich microchip included top glass plate, PDMS membrane replica with microfluidic networks and optical fiber, flat PDMS membrane and bottom glass plate. As the tip of excitation optical fiber completely contacted with the separation microchannel in this integrated microchip, it not only increased the excitation light intensity to achieve the high sensitivity, but also reduced the diameter of excitation beam to obtain high resolution. In addition, we found that this rigid PDMS sandwich microchip structure effectively prevented PDMS microchannel distortion from rigid optical fiber, and provided a substantial convenience for microchips manipulating. A blue light-emitting diode (LED) was applied as excitation source by using optical fiber to couple excitation light into its direct-contacting microchannel for fluorescence detection. The performances of this integrated PDMS sandwich microchip was demonstrated by separating the mixture of sodium fluorescein (SF) and fluorescein isothiocyanate isomer I (FITC), and showed a higher sensitive and resolution than those obtained from the conventional integrated optical-fiber PDMS microchip with a 100-microm distance between fiber tip and separation microchannel. Additionally, the reproducibility of this integrated microchip with LED-induced fluorescence detection was also examined by separation of a mixture of FITC-labeled amino acids.

  5. "DNA Origami Traffic Lights" with a Split Aptamer Sensor for a Bicolor Fluorescence Readout.

    PubMed

    Walter, Heidi-Kristin; Bauer, Jens; Steinmeyer, Jeannine; Kuzuya, Akinori; Niemeyer, Christof M; Wagenknecht, Hans-Achim

    2017-04-12

    A split aptamer for adenosine triphosphate (ATP) was embedded as a recognition unit into two levers of a nanomechanical DNA origami construct by extension and modification of selected staple strands. An additional optical module in the stem of the split aptamer comprised two different cyanine-styryl dyes that underwent an energy transfer from green (donor) to red (acceptor) emission if two ATP molecules were bound as target molecule to the recognition module and thereby brought the dyes in close proximity. As a result, the ATP as a target triggered the DNA origami shape transition and yielded a fluorescence color change from green to red as readout. Conventional atomic force microscopy (AFM) images confirmed the topology change from the open form of the DNA origami in the absence of ATP into the closed form in the presence of the target molecule. The obtained closed/open ratios in the absence and presence of target molecules tracked well with the fluorescence color ratios and thereby validated the bicolor fluorescence readout. The correct positioning of the split aptamer as the functional unit farthest away from the fulcrum of the DNA origami was crucial for the aptasensing by fluorescence readout. The fluorescence color change allowed additionally to follow the topology change of the DNA origami aptasensor in real time in solution. The concepts of fluorescence energy transfer for bicolor readout in a split aptamer in solution, and AFM on surfaces, were successfully combined in a single DNA origami construct to obtain a bimodal readout. These results are important for future custom DNA devices for chemical-biological and bioanalytical purposes because they are not only working as simple aptamers but are also visible by AFM on the single-molecule level.

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

    Red and blue light are both vital factors for plant growth and development. We examined how different ratios of red light to blue light (R/B) provided by light-emitting diodes affected photosynthetic performance by investigating parameters related to photosynthesis, including leaf morphology, photosynthetic rate, chlorophyll fluorescence, stomatal development, light response curve, and nitrogen content. In this study, lettuce plants (Lactuca sativa L.) were exposed to 200 μmol⋅m−2⋅s−1 irradiance for a 16 h⋅d−1 photoperiod under the following six treatments: monochromatic red light (R), monochromatic blue light (B) and the mixture of R and B with different R/B ratios of 12, 8, 4, and 1. Leaf photosynthetic capacity (Amax) and photosynthetic rate (Pn) increased with decreasing R/B ratio until 1, associated with increased stomatal conductance, along with significant increase in stomatal density and slight decrease in stomatal size. Pn and Amax under B treatment had 7.6 and 11.8% reduction in comparison with those under R/B = 1 treatment, respectively. The effective quantum yield of PSII and the efficiency of excitation captured by open PSII center were also significantly lower under B treatment than those under the other treatments. However, shoot dry weight increased with increasing R/B ratio with the greatest value under R/B = 12 treatment. The increase of shoot dry weight was mainly caused by increasing leaf area and leaf number, but no significant difference was observed between R and R/B = 12 treatments. Based on the above results, we conclude that quantitative B could promote photosynthetic performance or growth by stimulating morphological and physiological responses, yet there was no positive correlation between Pn and shoot dry weight accumulation. PMID:27014285

  8. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta).

    PubMed

    Wu, Huanyang

    2016-01-01

    Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.

  9. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta)

    PubMed Central

    2016-01-01

    Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation. PMID:27642603

  10. Mass-independent fractionation of mercury isotopes in compact fluorescent light bulbs

    NASA Astrophysics Data System (ADS)

    Mead, C.; Anbar, A. D.; Lyons, J. R.; Johnson, T. M.

    2010-12-01

    Compact fluorescent lightbulbs (CFLs) are a growing source of Hg pollution. The high-energy environment of the CFLs combined with the known partitioning of Hg into the bulb walls could provide an environment for unusual isotope fractionation that could be used to trace pollution from improper bulb disposal. To investigate this possibility, we analyzed the isotope composition of Hg in CFL glass, phosphor powder, and whole bulbs from CFLs of known ages. We observed large, mass-independent fractionation of Hg isotopes between Hg embedded in the bulb wall and Hg in the liquid and vapor phases, which are the initial reservoir of Hg in the bulb. This fractionation results in the bulb wall showing enrichment of 198Hg, 199Hg, 200Hg, 201Hg, and 204Hg relative to 202Hg, the most abundant isotope. Both the amount of Hg embedded in the glass and the magnitude of the isotope enrichment were found to increase with the number of hours of light bulb use. For a CFL used for 3600 hours (with a rated lifetime of 10,000 hours), the isotopic composition of the Hg in the glass was enriched by 34.5‰, 4.1‰, 6.3‰, 21.1‰, and 12.1‰ for 198Hg/202Hg, 199Hg/202Hg, 200Hg/202Hg, 201Hg/202Hg, and 204Hg/202Hg, respectively, compared to NIST SRM-3133. This pattern of isotope enrichments is not correlated with mass differences for any of the isotope ratios. In contrast, the other mass-independent effects that have recently been observed in Hg isotopes (i.e., the nuclear volume and magnetic isotope effects) resemble mass-dependent fractionation for the even mass isotopes and are anomalous only for the odd mass isotopes, 199Hg and 201Hg. First order theoretical calculations using Hg absorption and emission data for each of the hyperfine components of the 253.7 nm line have shown that similar fractionation can be produced through an optical self-shielding effect. This effect occurs because each Hg isotope has a different degree of optical saturation at their respective absorption wavelength

  11. Fluorescent Proteins as Biomarkers and Biosensors: Throwing Color Lights on Molecular and Cellular Processes

    PubMed Central

    Stepanenko, Olesya V.; Verkhusha, Vladislav V.; Kuznetsova, Irina M.; Uversky, Vladimir N.; Turoverov, K.K.

    2010-01-01

    Green fluorescent protein (GFP) from jellyfish Aequorea victoria is the most extensively studied and widely used in cell biology protein. GFP-like proteins constitute a fast growing family as several naturally occurring GFP-like proteins have been discovered and enhanced mutants of Aequorea GFP have been created. These mutants differ from wild-type GFP by conformational stability, quantum yield, spectroscopic properties (positions of absorption and fluorescence spectra) and by photochemical properties. GFP-like proteins are very diverse, as they can be not only green, but also blue, orange-red, far-red, cyan, and yellow. They also can have dual-color fluorescence (e.g., green and red) or be non-fluorescent. Some of them possess kindling property, some are photoactivatable, and some are photoswitchable. This review is an attempt to characterize the main color groups of GFP-like proteins, describe their structure and mechanisms of chromophore formation, systemize data on their conformational stability and summarize the main trends of their utilization as markers and biosensors in cell and molecular biology. PMID:18691124

  12. Fluorescent proteins as biomarkers and biosensors: throwing color lights on molecular and cellular processes.

    PubMed

    Stepanenko, Olesya V; Verkhusha, Vladislav V; Kuznetsova, Irina M; Uversky, Vladimir N; Turoverov, K K

    2008-08-01

    Green fluorescent protein (GFP) from jellyfish Aequorea victoria is the most extensively studied and widely used in cell biology protein. GFP-like proteins constitute a fast growing family as several naturally occurring GFP-like proteins have been discovered and enhanced mutants of Aequorea GFP have been created. These mutants differ from wild-type GFP by conformational stability, quantum yield, spectroscopic properties (positions of absorption and fluorescence spectra) and by photochemical properties. GFP-like proteins are very diverse, as they can be not only green, but also blue, orange-red, far-red, cyan, and yellow. They also can have dual-color fluorescence (e.g., green and red) or be non-fluorescent. Some of them possess kindling property, some are photoactivatable, and some are photoswitchable. This review is an attempt to characterize the main color groups of GFP-like proteins, describe their structure and mechanisms of chromophore formation, systemize data on their conformational stability and summarize the main trends of their utilization as markers and biosensors in cell and molecular biology.

  13. Recording of individual identification information on dental prostheses using fluorescent material and ultraviolet light.

    PubMed

    Naito, Yoshihito; Meinar, Ashrin N; Iwawaki, Yuki; Kashiwabara, Toshiya; Goto, Takaharu; Ito, Teruaki; Sakuma, Tetsuro; Ichikawa, Tetsuo

    2013-01-01

    The placement of individual identification on a prosthesis is very important for forensic dentistry and traceability. This article describes the unique naming/labeling of dentures with information for individual identification using a method in which information is invisible under natural light but visible under ultraviolet light-emitting diode/black light exposure. The use of laser beam machining with this method will enable the recording of a large amount of information.

  14. Design and development of a LabVIEW-based LED-induced fluorescence spectroscopy system with applications in non-destructive quality assessment of agricultural products

    NASA Astrophysics Data System (ADS)

    Abbasi, Hamed; Nazeri, Majid; Mireei, Seyed Ahmad

    2016-01-01

    Over the past several years, the demand for high quality agricultural products has been remarkably increased. Thus, it is important to use non-destructive methods for product quality monitoring. LED-induced fluorescence spectroscopy has proved its potential for nondestructive detection of some defects in agricultural products, such as tissue browning and bruising. Due to such defects, changes in the polyphenol and chlorophyll contents occur which can be considered as the visible marks of decreasing fruit quality. In the present work, a fluorescence spectrometer (spectrofluorometer) controlled by LabVIEW software was designed and developed. In this spectrometer, a consumer-grade webcam was used as an imaging sensor. The spectrometer was able to measure the fluorescence spectra directly from the fruit and vegetable surface in the desired regions. To do so, the spectrometer was equipped with a suitable fiber-optic probe. The hardware solution was based on data acquisition working on the USB platform and controlled by the application running on the PC. In this system, light emitting diodes with different wavelengths were used as the excitation sources for inducing fluorescence spectra of some famous fruits and vegetables.

  15. Enhancement of fluorescence development of end products by use of a fluorescence developer solution in a rapid and sensitive fluorescent spot test for specific detection of microbial beta-lactamases.

    PubMed

    Chen, K C; Holmes, K K

    1986-03-01

    A fluorescent spot test method for specific detection of microbial beta-lactamases as previously published (K. C. S. Chen, J. S. Knapp, and K. K. Holmes, J. Clin. Microbiol. 19:818-825, 1984) was improved by the use of a fluorescence developer solution. The fluorescence developer solution used in this study consisted of 0.78 M sodium tartrate buffer containing 12% formaldehyde at a final pH of 4.5. An addition of 1 volume of fluorescence developer solution to 5 volumes of ampicillin or cephalex substrate solution incubated with beta-lactamase-producing organisms, followed by heating the mixture at 45 degrees C for 10 min resulted in enhancement of fluorescence of the end products of beta-lactamase activity. This provides a more sensitive assay for microbial beta-lactamases and offers the potential for direct detection of beta-lactamases in clinical specimens.

  16. Promising operational stability of high-efficiency organic light-emitting diodes based on thermally activated delayed fluorescence

    PubMed Central

    Nakanotani, Hajime; Masui, Kensuke; Nishide, Junichi; Shibata, Takumi; Adachi, Chihaya

    2013-01-01

    Organic light-emitting diodes (OLEDs) are attractive for next-generation displays and lighting applications because of their potential for high electroluminescence (EL) efficiency, flexibility and low-cost manufacture. Although phosphorescent emitters containing rare metals such as iridium or platinum produce devices with high EL efficiency, these metals are expensive and their blue emission remains unreliable for practical applications. Recently, a new route to high EL efficiency using materials that emit through thermally activated delayed fluorescence (TADF) was demonstrated. However, it is unclear whether devices that emit through TADF, which originates from the contributions of triplet excitons, are reliable. Here we demonstrate highly efficient, stable OLEDs that emit via TADF by controlling the position of the carrier recombination zone, resulting in projected lifetimes comparable to those of tris(2-phenylpyridinato)iridium(III)-based reference OLEDs. Our results indicate that TADF is intrinsically stable under electrical excitation and optimization of the surrounding materials will enhance device reliability. PMID:23820465

  17. Subtle spectral effects accompanying the assembly of bacteriochlorophylls into cyclic light harvesting complexes revealed by high-resolution fluorescence spectroscopy

    SciTech Connect

    Rätsep, Margus Pajusalu, Mihkel Linnanto, Juha Matti; Freiberg, Arvi

    2014-10-21

    We have observed that an assembly of the bacteriochloropyll a molecules into B850 and B875 groups of cyclic bacterial light-harvesting complexes LH2 and LH1, respectively, results an almost total loss of the intra-molecular vibronic structure in the fluorescence spectrum, and simultaneously, an essential enhancement of its phonon sideband due to electron-phonon coupling. While the suppression of the vibronic coupling in delocalized (excitonic) molecular systems is predictable, as also confirmed by our model calculations, a boost of the electron-phonon coupling is rather unexpected. The latter phenomenon is explained by exciton self-trapping, promoted by mixing the molecular exciton states with charge transfer states between the adjacent chromophores in the tightly packed B850 and B875 arrangements. Similar, although less dramatic trends were noted for the light-harvesting complexes containing chlorophyll pigments.

  18. Rewiring Multidomain Protein Switches: Transforming a Fluorescent Zn(2+) Sensor into a Light-Responsive Zn(2+) Binding Protein.

    PubMed

    Aper, Stijn J A; Merkx, Maarten

    2016-07-15

    Protein-based sensors and switches provide attractive tools for the real-time monitoring and control of molecular processes in complex biological environments. Fluorescent sensor proteins have been developed for a wide variety of small molecules, but the construction of genetically encoded light-responsive ligand binding proteins remains mostly unexplored. Here we present a generic approach to reengineer a previously developed FRET-based Zn(2+) sensor into a light-activatable Zn(2+) binding protein using a design strategy based on mutually exclusive domain interactions. These so-called VividZn proteins consist of two light-responsive Vivid domains that homodimerize upon illumination with blue light, thus preventing the binding of Zn(2+) between two Zn(2+) binding domains, Atox1 and WD4. Following optimization of the linker between WD4 and the N-terminus of one of the Vivid domains, VividZn variants were obtained that show a 9- to 55-fold decrease in Zn(2+) affinity upon illumination, which is fully reversible following dark adaptation. The Zn(2+) affinities of the switch could be rationally tuned between 1 pM and 2 nM by systematic variation of linker length and mutation of one of the Zn(2+) binding residues. Similarly, introduction of mutations in the Vivid domains allowed tuning of the switching kinetics between 10 min and 7 h. Low expression levels in mammalian cells precluded the demonstration of light-induced perturbation of cytosolic Zn(2+) levels. Nonetheless, our results firmly establish the use of intramolecular Vivid dimerization as an attractive light-sensitive input module to rationally engineer light-responsive protein switches based on mutually exclusive domain interactions.

  19. Fluorescence light microscopy of pulmonary surfactant at the air-water interface of an air bubble of adjustable size.

    PubMed

    Knebel, D; Sieber, M; Reichelt, R; Galla, H-J; Amrein, M

    2002-07-01

    The structural dynamics of pulmonary surfactant was studied by epifluorescence light microscopy at the air-water interface of a bubble as a model close to nature for an alveolus. Small unilamellar vesicles of dipalmitoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, a small amount of a fluorescent dipalmitoylphosphatidylcholine-analog, and surfactant-associated protein C were injected into the buffer solution. They aggregated to large clusters in the presence of Ca(2+) and adsorbed from these units to the interface. This gave rise to an interfacial film that eventually became fully condensed with dark, polygonal domains in a fluorescent matrix. When now the bubble size was increased or decreased, respectively, the film expanded or contracted. Upon expansion of the bubble, the dark areas became larger to the debit of the bright matrix and reversed upon contraction. We were able to observe single domains during the whole process. The film remained condensed, even when the interface was increased to twice its original size. From comparison with scanning force microscopy directly at the air-water interface, the fluorescent areas proved to be lipid bilayers associated with the (dark) monolayer. In the lung, such multilayer phase acts as a reservoir that guarantees a full molecular coverage of the alveolar interface during the breathing cycle and provides mechanical stability to the film.

  20. A Fluorescence Light-Up Ag Nanocluster Probe that Discriminates Single-Nucleotide Variants by Emission Color

    PubMed Central

    Yeh, Hsin-Chih; Sharma, Jaswinder; Shih, Ie-Ming; Vu, Dung M.; Martinez, Jennifer S.; Werner, James H.

    2012-01-01

    Rapid and precise screening of small genetic variations, such as single-nucleotide polymorphisms (SNPs), among an individual’s genome is still an unmet challenge at point-of-care settings. One crucial step towards this goal is the development of discrimination probes that require no enzymatic reaction and are easy to use. Here we report a new type of fluorescent molecular probe, termed a chameleon NanoCluster Beacon (cNCB), that lights up into different colors upon binding SNP targets. NanoCluster Beacons (NCBs) are collections of a small number of Ag atoms templated on single-stranded DNA that fluoresce strongly when placed in proximity to particular DNA sequences, termed enhancers. Here we show the fluorescence emission color of a NCB can change substantially (a shift of 60–70 nm in the emission maximum) depending upon the alignment between the silver nanocluster and the DNA enhancer sequence. Chameleon NCBs exploit this color shift to directly detect SNPs, based on the fact that different SNPs produce a different alignment between the Ag nanocluster and the enhancer. This SNP detection method has been validated on all single-nucleotide substitution scenarios in three synthetic DNA targets, in six disease-related SNP targets, and in two clinical samples taken from patients with ovarian serous borderline tumors. Samples with single-nucleotide variations can be easily identified by the naked eye under UV excitation, making this method a reliable and low-cost assay with a simple readout format. PMID:22775452

  1. A fluorescence light-up Ag nanocluster probe that discriminates single-nucleotide variants by emission color.

    PubMed

    Yeh, Hsin-Chih; Sharma, Jaswinder; Shih, Ie-Ming; Vu, Dung M; Martinez, Jennifer S; Werner, James H

    2012-07-18

    Rapid and precise screening of small genetic variations, such as single-nucleotide polymorphisms (SNPs), among an individual's genome is still an unmet challenge at point-of-care settings. One crucial step toward this goal is the development of discrimination probes that require no enzymatic reaction and are easy to use. Here we report a new type of fluorescent molecular probe, termed a chameleon NanoCluster Beacon (cNCB), that lights up into different colors upon binding SNP targets. NanoCluster Beacons (NCBs) are collections of a small number of Ag atoms templated on single-stranded DNA that fluoresce strongly when placed in proximity to particular DNA sequences, termed enhancers. Here we show the fluorescence emission color of a NCB can change substantially (a shift of 60-70 nm in the emission maximum) depending upon the alignment between the silver nanocluster and the DNA enhancer sequence. Chameleon NCBs exploit this color shift to directly detect SNPs, based on the fact that different SNPs produce a different alignment between the Ag nanocluster and the enhancer. This SNP detection method has been validated on all single-nucleotide substitution scenarios in three synthetic DNA targets, in six disease-related SNP targets, and in two clinical samples taken from patients with ovarian serous borderline tumors. Samples with single-nucleotide variations can be easily identified by the naked eye under UV excitation, making this method a reliable and low-cost assay with a simple readout format.

  2. LED Lighting Facts® Program Supports Accuracy in SSL Product Information

    SciTech Connect

    2013-09-30

    Fact sheet that provides a summary of LED Lighting Facts, a program to assure that LED lighting is accurately represented in the marketplace, illustrated by the LED Lighting Facts label to disclose product performance data.

  3. Microneedles rollers as a potential device to increase ALA diffusion and PpIX production: evaluations by wide-field fluorescence imaging and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Gracielli Sousa, R. Phamilla; de Menezes, Priscila F. C.; Fujita, Alessandra K. L.; Requena, Michelle B.; Govone, Angelo Biassi; Escobar, André; de Nardi, Andrigo B.; Kurachi, Cristina; Bagnato, Vanderlei Salvador

    2014-03-01

    One of the limitations of topical photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) is the poor ability to penetrate biological barriers of skin and the recurrence rates in treatments. This study aimed to identify possible signs of increased diffusion of ALA-induced PpIX by fluorescence images and fluorescence spectroscopy. The research was done using in vivo porcine skin model. Before the cream application, microholes was performed with microneedles rollers in only one direction, afterward the ALA cream was applied at a 2.5cm2 area in triplicate and an occlusive dressing was placed. PpIX production was monitored using fluorescence spectroscopy collected at skin surface after 70, 100, 140, and 180 minutes of ALA incubation. About 100 fluorescence spectra of each treatment were collected, distributed by about five points for each site. Wide-field fluorescence imaging was made after 70, 90, and 170 minutes after treatment. The results obtained by imaging analysis indicated increase of the PpIX diffusion in the skin surface using the microneedles rollers (MNs) before ALA application. Circular regions of red fluorescence around the microholes were observed. In addition, the fluorescence spectra showed a greater intensity (2 times as many) in groups microneedles rollers associated. In conclusion, our data shown greater homogeneity and PpIX production in the groups pre-treated with microneedles indicating that the technique can be used to greater uniformity of PpIX production throughout the area to be treated reducing the chances of recurrent tumor as well as has potential for decreasing the time of therapy. (FUNDING SUPPORT:CAPES, CNPq and FAPESP)

  4. Design of chlorophyll-a and turbidity sensor based on fluorescence induction and scattering-light detection

    NASA Astrophysics Data System (ADS)

    Zhang, Keke; Liu, Shixuan; Chen, Shizhe; Qi, Yong; Miao, Bin; Yan, Xingkui; Bai, Xuejiao

    2014-07-01

    The chlorophyll-a and turbidity sensor based on the principles of fluorescence induction and scattering-light detection is designed. Using fluorescence induction technology, scattering-light detection technology and weak signal detection technology, chlorophyll-a concentration measurement and turbidity measurement in seawater are integrated in a set of testing equipment to implement software and hardware reuse and improve the integration of the device, which has the features of small size and easy operation. The comparative experiments and repetitive experiments are completed with ALEC ACLW-CAR chlorophyll / turbidity sensor. Experiment results show that chlorophyll-a concentration, turbidity and the system output values have good linear relationships, and the fitting coefficients are 0.999. Repeatability standard deviations of chlorophyll-a detection and turbidity detection are better than 0.08 μg/L and 0.04 FTU, respectively, and the accuracy of the device within +/- 2%. Chlorophyll-a and turbidity in-situ monitoring in seawater can be achieved using this testing equipment.

  5. A facile light-emitting-diode induced fluorescence detector coupled to an integrated microfluidic device for microchip electrophoresis.

    PubMed

    Yang, Fan; Li, Xin-chun; Zhang, Wen; Pan, Jian-bin; Chen, Zuan-guang

    2011-05-30

    In this paper, a compact and inexpensive light emitting diode induced fluorescence (LED-IF) detector with simplified optical configuration was developed and assembled in an integrated microfluidic device for microscale electrophoresis. The facile detector mainly consisted of an LED, a focusing pinhole, an emission filter and a photodiode, and was encapsulated in the upper layer of an aluminum alloy device with two layers. At the bottom layer, integrated circuit (IC) was assembled to manipulate the voltage for sample injection and separation, LED emission and signal amplifying. A high-power LED with fan-shaped heat sink was used as excitation source. The excitation light was focused by a 1.1mm diameter pinhole fabricated in a thin piece of silver foil, and the obtained sensitivity was about 3 times as high as that using electrode plate. Other important parameters including LED driven current, fluorescence collection angle and detection distance have also been investigated. Under optimal conditions, considerable high-response of 0.09 fmol and 0.18 fmol mass detection limits at 0.37 nL injection volume for sodium fluorescein (SF) and FITC was achieved, respectively. This device has been successfully employed to separate penicillamine (PA) enantiomers. Due to such significant features as low-cost, integration, miniaturization, and ease of commercialization, the presented microfluidic device may hold great promise for clinical diagnostics and bioanalytical applications.

  6. Tea quality and classification evaluation using multi-wavelength light-emitting diodes induced fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Liu, Xuan; Yan, Chunsheng; He, Sailing; Mei, Liang

    2013-03-01

    In this paper, we demonstrated a detective system to evaluate the quality and classification of different tea samples based on multi-wavelength LED-induced fluorescence spectroscopy. By utilizing multiple excitation wavelengths, we obtained much more physical and chemical information from the detected samples than single excitation wavelength. By utilizing principal component analysis (PCA), we extracted the dominant features of the samples to classify and characterize the tea samples.

  7. Two-photon light-sheet nanoscopy by fluorescence fluctuation correlation analysis

    NASA Astrophysics Data System (ADS)

    Chen, Xuanze; Zong, Weijian; Li, Rongqin; Zeng, Zhiping; Zhao, Jia; Xi, Peng; Chen, Liangyi; Sun, Yujie

    2016-05-01

    Advances in light-sheet microscopy have enabled the fast three-dimensional (3D) imaging of live cells and bulk specimens with low photodamage and phototoxicity. Combining light-sheet illumination with super-resolution imaging is expected to resolve subcellular structures. Actually, such kind of super-resolution light-sheet microscopy was recently demonstrated using a single-molecule localization algorithm. However, the imaging depth and temporal resolution of this method are limited owing to the requirements of precise single molecule localization and reconstruction. In this work, we present two-photon super-resolution light-sheet imaging via stochastic optical fluctuation imaging (2PLS-SOFI), which acquires high spatiotemporal resolution and excellent optical sectioning ability. 2PLS-SOFI is based on non-linear excitation of fluctuation/blinking probes using our recently developed fast two-photon three-axis digital scanned light-sheet microscope (2P3A-DSLM), which enables both deep penetration and thin sheet of light. Overall, 2PLS-SOFI demonstrates up to 3-fold spatial resolution enhancement compared with conventional two-photon light-sheet (2PLS) microscopy and about 40-fold temporal resolution enhancement compared with individual molecule localization-selective plane illumination microscopy (IML-SPIM). Therefore, 2PLS-SOFI is promising for 3D long-term, deep-tissue imaging with high spatiotemporal resolution.

  8. Comparison of solar-induced chlorophyll fluorescence, light-use efficiency, and process-based GPP models in maize.

    PubMed

    Wagle, Pradeep; Zhang, Yongguang; Jin, Cui; Xiao, Xiangming

    2016-06-01

    Accurately quantifying cropland gross primary production (GPP) is of great importance to monitor cropland status and carbon budgets. Satellite-based light-use efficiency (LUE) models and process-based terrestrial biosphere models (TBMs) have been widely used to quantify cropland GPP at different scales in past decades. However, model estimates of GPP are still subject to large uncertainties, especially for croplands. More recently, space-borne solar-induced chlorophyll fluorescence (SIF) has shown the ability to monitor photosynthesis from space, providing new insights into actual photosynthesis monitoring. In this study, we examined the potential of SIF data to describe maize phenology and evaluated three GPP modeling approaches (space-borne SIF retrievals, a LUE-based vegetation photosynthesis model [VPM], and a process-based soil canopy observation of photochemistry and energy flux [SCOPE] model constrained by SIF) at a maize (Zea mays L.) site in Mead, Nebraska, USA. The result shows that SIF captured the seasonal variations (particularly during the early and late growing season) of tower-derived GPP (GPP_EC) much better than did satellite-based vegetation indices (enhanced vegetation index [EVI] and land surface water index [LSWI]). Consequently, SIF was strongly correlated with GPP_EC than were EVI and LSWI. Evaluation of GPP estimates against GPP_EC during the growing season demonstrated that all three modeling approaches provided reasonable estimates of maize GPP, with Pearson's correlation coefficients (r) of 0.97, 0.94, and 0.93 for the SCOPE, VPM, and SIF models, respectively. The SCOPE model provided the best simulation of maize GPP when SIF observations were incorporated through optimizing the key parameter of maximum carboxylation capacity (Vcmax). Our results illustrate the potential of SIF data to offer an additional way to investigate the seasonality of photosynthetic activity, to constrain process-based models for improving GPP estimates, and to

  9. Thin Film Packaging Solutions for High Efficiency OLED Lighting Products

    SciTech Connect

    2008-06-30

    The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology was characterized

  10. Chlorophyll fluorescence and the polarized underwater light field: comparison of vector radiative transfer simulations and multi-angular hyperspectral polarization field measurements

    NASA Astrophysics Data System (ADS)

    El-habashi, Ahmed; Ahmed, Samir

    2016-05-01

    Previous partial simulations and field measurements by us, had demonstrated the impact of the un-polarized nature of algal chlorophyll fluorescence to reduce the observed degree of polarization of the underwater light field in the spectral vicinity of fluorescence. (Polarization otherwise existing as a result of non-algal particulate (NAP) and molecular elastic scattering). The magnitude of this fluorescence driven dip in the observed degree of polarization was also seen to be theoretically related to the fluorescence magnitude. The recent availability to us of the RayXP vector radiative transfer code (VRTE) for the coupled atmosphere ocean system now permits us to make complete simulations of the underwater polarized light field, using measured inherent optical properties (IOPs) as inputs. Based on these simulations, a much more comprehensive analysis of the fluorescence impact is now possible. Combining the results of these new simulations with underwater field measurements in eutrophic waters using our hyperspectral multi angle polarimeter, we verified the theoretical relationship. In addition, comparisons of VRTE simulations and hyperspectral polarized field measurements for various coastal water conditions permit retrieval of fluorescence magnitudes. Comparisons of these polarization based fluorescence retrievals with retrievals obtained using fluorescence height over baseline or Hydrolight scalar simulations, together with total unpolarized radiance measurements, show good agreement.

  11. Daytime Cognitive Performance in Response to Sunlight or Fluorescent Light Controlling for Sleep Duration

    NASA Technical Reports Server (NTRS)

    Ramos, Jhanic; Zamos, Adela; Rao, Rohit; Flynn-Evans, Erin

    2015-01-01

    Light is the primary synchronizer of the human circadian rhythm and also has acute alerting effects. Our study involves and comparing the alertness, performance and sleep of participants in the NASA Ames Sustainability Base, which uses sunlight as its primary light source, to in a traditional office building which uses overhead florescent lighting and varying exposure to natural light. The purpose of this study is to determine whether the use of natural lighting as a primary light source improves daytime cognitive function and promotes nighttime sleep. Participants from the Sustainability Base will be matched by gender and age to individuals working in other NASA buildings. In a prior study we found no differences in performance between those working in the Sustainability Base and those working in other buildings. Unexpectedly, we found that the average sleep duration among participants in both buildings was short, which likely obscured our ability to detect a difference the effect of light exposure on alertness. Given that such sleep deprivation has negative effects on cognitive performance, in this iteration of the study we are asking the participants to maintain a regular schedule with eight hours in bed each night in order to control for the effect of self-selected sleep restriction. Over the course of one week, we will ask the participants to wear actiwatches continuously, complete a psychomotor vigilance task (PVT) and digit symbol substitution task (DSST) three times per day, and keep daily sleepwork diaries. We hope that this study will provide data to support the idea that natural lighting and green architectural design are optimal to enhance healthy nighttime sleep patterns and daytime cognitive performance.

  12. Adaptation of photosystem II to high and low light in wild-type and triazine-resistant Canola plants: analysis by a fluorescence induction algorithm.

    PubMed

    van Rensen, Jack J S; Vredenberg, Wim J

    2011-09-01

    Plants of wild-type and triazine-resistant Canola (Brassica napus L.) were exposed to very high light intensities and after 1 day placed on a laboratory table at low light to recover, to study the kinetics of variable fluorescence after light, and after dark-adaptation. This cycle was repeated several times. The fast OJIP fluorescence rise curve was measured immediately after light exposure and after recovery during 1 day in laboratory room light. A fluorescence induction algorithm has been used for resolution and analysis of these curves. This algorithm includes photochemical and photo-electrochemical quenching release components and a photo-electrical dependent IP-component. The analysis revealed a substantial suppression of the photo-electrochemical component (even complete in the resistant biotype), a partial suppression of the photochemical component and a decrease in the fluorescence parameter F (o) after high light. These effects were recovered after 1 day in the indoor light.

  13. Acetoacetate promotes the formation of fluorescent advanced glycation end products (AGEs).

    PubMed

    Bohlooli, Mousa; Ghaffari-Moghaddam, Mansour; Khajeh, Mostafa; Aghashiri, Zohre; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2016-12-01

    Acetoacetate (AA) is an important ketone body, which produces reactive oxygen species (ROS). Advanced glycation end products (AGEs) are defined as final products of glycation process whose production is influenced by the levels of ROS. The accumulation of AGEs in the body contributes to pathogenesis of many diseases including complications of diabetes, and Alzheimer's and Parkinson's disease. Here, we evaluated the impact of AA on production of AGEs upon incubation of human serum albumin (HSA) with glucose. The effect of AA on the AGEs formation of HSA was studied under physiological conditions after incubation with glucose for 35 days. The physical techniques including circular dichroism (CD) and fluorescence spectroscopy were used to assess the impact of AA on formation and structural changes of glycated HSA (GHSA). Our results indicated that the secondary and tertiary structural changes of GHSA were increased in the presence of AA. The fluorescence intensity measurements of AGEs also showed an increase in AGEs formation. Acetoacetate has an activator effect in formation of AGEs through ROS production. The presence of AA may result in enhanced glycation in the presence of glucose and severity of complications associated with accumulation of AGEs.

  14. Production of the ideal sample shape for Total Reflection X-ray Fluorescence analysis

    NASA Astrophysics Data System (ADS)

    Horntrich, C.; Kregsamer, P.; Prost, J.; Stadlbauer, F.; Wobrauschek, P.; Streli, C.

    2012-11-01

    Total Reflection X-ray Fluorescence analysis (TXRF) is a well-established analytical method in the semiconductor industry for the analysis of silicon wafer surfaces. For the calibration of the spectrometer typically an external standard is used which is sensitive to quantification errors. In general TXRF is known to allow for linear calibration. For small sample amounts (pg to ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. For higher total amounts of sample the relation between fluorescence intensity and sample amount diverges from linearity (saturation effect). These deviations lead to difficulties in quantification with external standard. Content of the presented work is the production of the ideal TXRF sample shape, which was theoretically determined to be ring shaped. A possibility for the production of samples with ring shape is the use of a nanodispensing system combined with a positioning device. Therewith it is possible to produce ring shaped samples in a controlled way with the ring consisting of individual nanodroplets, so that the wanted diameter of the ring can be chosen. A comparison of the fluorescence intensities emitted by contracted and ring shaped samples shows that the ring shape is not only theoretically the best TXRF shape but also experimentally. It could be proven that for contracted samples the saturation effect occurs at a lower sample mass than for samples with ring shape.

  15. Degradation products from consumer nanocomposites - a case study on quantum dot lighting

    PubMed Central

    Liu, Jingyu; Katahara, John; Li, Guanglai; Coe-Sullivan, Seth; Hurt, Robert H.

    2012-01-01

    Most nanomaterials enter the natural environment as nano-enabled products, which are typically composites with primary nanoparticles bound on substrates or embedded in liquid or solid matrices. The environmental risks associated with these products are expected to differ from those associated with the as-produced particles. This article presents a case study on the end-of-life emission of a commercial prototype polymer/quantum-dot (QD) composite used in solid-state lighting for homes. We report the extent of cadmium release upon exposure to a series of environmental and biological simulant fluids, and track the loss of QD-characteristic fluorescence as a marker for chemical damage to the CdSe/ZnS nanoparticles. Measured cadmium releases after 30-day exposure range from 0.007-1.2 mg/g of polymer, and the higher values arise for low-pH simulants containing nitric or gastric acid. Centrifugal ultrafiltration and ICP was used to distinguish soluble cadmium from particulate forms. The leachate is found to contain soluble metals with no evidence of free QDs or QD-containing polymeric debris. The absence of free nanoparticles suggests that this product does not raise nanotechnology-specific environmental issues associated with degradation and leaching, but is more usefully regarded as a conventional chemical product that is a potential source of small amounts of soluble cadmium. PMID:22352378

  16. Interactions of hypericin with a model mutagen - Acridine orange analyzed by light absorption and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Pietrzak, Monika; Szabelski, Mariusz; Kasparek, Adam; Wieczorek, Zbigniew

    2017-02-01

    The present study was designed to estimate the ability of hypericin to interact with a model mutagen - acridine orange. The hetero-association of hypericin and acridine orange was investigated with absorption and fluorescence spectroscopy methods in aqueous solution of DMSO. The data indicate that hypericin forms complexes with acridine orange and that the association constants are relatively high and depend on DMSO concentration. The absorption spectra of the hypericin - acridine orange complexes were examined as well. Owing to its ability to interact with flat aromatic compounds, hypericin may potentially be used as an interceptor molecule.

  17. Indication of transthylakoid proton-fluxes in Aegopodium podagraria L. by light-induced changes of plasmalemma potential, chlorophyll fluorescence and light-scattering.

    PubMed

    Vanselow, K H; Dau, H; Hansen, U P

    1988-12-01

    The time course of the responses of chlorophyll fluorescence in leaves of Aegopodium podagraria to changes in irradiance does not necessarily show the time constant of thylakoid energization at energy fluence rates below 10-25 W·m(-2). In addition, other measures of thylakoid energization, such as lightscattering at 532 nm and the responses to saturating flashes, show that the related component disappears from these signals at low fluence rates, but not necessarily all together at the same fluence rate. However, this time constant still appears in the light-induced responses of the plasmalemma potential. This implies that the effect on the electrogenic proton pump in the plasmalemma is the most sensitive indicator of proton fluxes into the inner thylakoid space. These results are a further indication that energy-quenching is coupled ther indication that energy-quenching is coupled to transthylakoid proton fluxes via an intermediate, which is not active in Aegopodium podagraria at low irradiances.

  18. Study of photosynthetic productivity in the Northern Gulf of Mexico: Importance of diel cycles and light penetration

    NASA Astrophysics Data System (ADS)

    Zhao, Yan; Quigg, Antonietta

    2015-07-01

    Based on 14C uptake assays, in vivo chlorophyll (chl) a fluorescence and HPLC pigment analysis, phytoplankton photosynthetic physiology and productivity in 24-h diel cycles were characterized at three stations in April and August 2012 in the Northern Gulf of Mexico. The results indicated the sub-pycnocline primary production accounted for 5-48% of the total integrated primary production, emphasizing the important influence of euphotic zone in shallow coastal areas. During the diel cycles, chl a-specific light-saturated photosynthesis (PmaxB) as measured with photosynthesis versus irradiance curves (P-I) and the photoprotective pigment pool (diadinoxanthin, diatoxanthin, chl a) showed phytoplankton acclimation to be strongly influenced by water column structure (mixing versus stratification). Changes in chl a fluorescence and transformations between photoprotective pigments were most recognizable in surface samples. The dominate phytoplankton groups (diatoms and cyanobacteria in April and August respectively) also influenced the measured photosynthetic parameters. The Northern Gulf of Mexico is a typical coastal ecosystem with high variability of nutrients, light (intensity and attenuation) and mixing. Our study provided evidence that phytoplankton in this area are adapted to changing environmental conditions by means of fast responses as well as long-term photoacclimation strategies. Understanding the major drivers could help us to improve models involving the calculation of primary productivity, such as those focused towards understanding mechanisms controlling hypoxia.

  19. Trimodal detection of early childhood caries using laser light scanning and fluorescence spectroscopy: clinical prototype

    PubMed Central

    Kim, Amy S.; Ridge, Jeremy S.; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2013-01-01

    Abstract. There is currently a need for a safe and effective way to detect and diagnose early stages of childhood caries. A multimodal optical clinical prototype for diagnosing caries demineralization in vivo has been developed. The device can be used to quickly image and screen for any signs of demineralized enamel by obtaining high-resolution and high-contrast surface images using a 405-nm laser as the illumination source, as well as obtaining autofluorescence and bacterial fluorescence images. When a suspicious region of demineralization is located, the device also performs dual laser fluorescence spectroscopy using 405- and 532-nm laser excitation. An autofluorescence ratio of the two excitation lasers is computed and used to quantitatively diagnose enamel health. The device was tested on five patients in vivo as well as on 28 extracted teeth with clinically diagnosed carious lesions. The device was able to provide detailed images that highlighted the lesions identified by the clinicians. The autofluorescence spectroscopic ratios obtained from the extracted teeth successfully quantitatively discriminated between sound and demineralized enamel. PMID:23986369

  20. New light on ion channel imaging by total internal reflection fluorescence (TIRF) microscopy.

    PubMed

    Yamamura, Hisao; Suzuki, Yoshiaki; Imaizumi, Yuji

    2015-05-01

    Ion channels play pivotal roles in a wide variety of cellular functions; therefore, their physiological characteristics, pharmacological responses, and molecular structures have been extensively investigated. However, the mobility of an ion channel itself in the cell membrane has not been examined in as much detail. A total internal reflection fluorescence (TIRF) microscope allows fluorophores to be imaged in a restricted region within an evanescent field of less than 200 nm from the interface of the coverslip and plasma membrane in living cells. Thus the TIRF microscope is useful for selectively visualizing the plasmalemmal surface and subplasmalemmal zone. In this review, we focused on a single-molecule analysis of the dynamic movement of ion channels in the plasma membrane using TIRF microscopy. We also described two single-molecule imaging techniques under TIRF microscopy: fluorescence resonance energy transfer (FRET) for the identification of molecules that interact with ion channels, and subunit counting for the determination of subunit stoichiometry in a functional channel. TIRF imaging can also be used to analyze spatiotemporal Ca(2+) events in the subplasmalemma. Single-molecule analyses of ion channels and localized Ca(2+) signals based on TIRF imaging provide beneficial pharmacological and physiological information concerning the functions of ion channels.

  1. Water permeability through biological membranes by isotopic effects of fluorescence and light scattering.

    PubMed Central

    Lawaczeck, R

    1984-01-01

    A light-scattering technique used to measure the water permeability across closed biomembranes is described, which is based on the different indices of refraction of D2O and H2O. This transient technique is compared with a similar method using D2O-sensitive fluorophores in the intravesicular space. The results of both techniques are equivalent although the signal-to-noise ratio favors the light-scattering or turbidity experiment. The light-scattering method is only applicable to larger particles (no point-scatterers) and is easily extended to biological objects. Data on the H2O/D2O exchange across membranes of ghosts from human erythrocytes suggest two mechanisms: the D2O and H2O permeation through the membrane and a slower D2O-induced conformational change of membraneous proteins. PMID:6546887

  2. Limited-view light sheet fluorescence microscopy for three dimensional volume imaging

    NASA Astrophysics Data System (ADS)

    Rasmi, C. K.; Mohan, Kavya; Madhangi, M.; Rajan, K.; Nongthomba, U.; Mondal, Partha P.

    2015-12-01

    We propose and demonstrate a limited-view light sheet microscopy (LV-LSM) for three dimensional (3D) volume imaging. Realizing that longer and frequent image acquisition results in significant photobleaching, we have taken limited angular views (18 views) of the macroscopic specimen and integrated with maximum likelihood (ML) technique for reconstructing high quality 3D volume images. Existing variants of light-sheet microscopy require both rotation and translation with a total of approximately 10-fold more views to render a 3D volume image. Comparatively, LV-LSM technique reduces data acquisition time and consequently minimizes light-exposure by many-folds. Since ML is a post-processing technique and highly parallelizable, this does not cost precious imaging time. Results show noise-free and high contrast volume images when compared to the state-of-the-art selective plane illumination microscopy.

  3. Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn

    PubMed Central

    Linkosalo, Tapio; Heikkinen, Juha; Pulkkinen, Pertti; Mäkipää, Raisa

    2014-01-01

    We studied the photosynthetic activity of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst) in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 1–3 times per week. We began by measuring shoots present in late winter (i.e., March 2013) before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only. We analyzed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence. The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 2013–2014 was unusually mild and similar to future conditions predicted by global climate models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration. PMID:24982664

  4. Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn.

    PubMed

    Linkosalo, Tapio; Heikkinen, Juha; Pulkkinen, Pertti; Mäkipää, Raisa

    2014-01-01

    We studied the photosynthetic activity of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst) in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 1-3 times per week. We began by measuring shoots present in late winter (i.e., March 2013) before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only. We analyzed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence. The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 2013-2014 was unusually mild and similar to future conditions predicted by global climate models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration.

  5. Quenching of chlorophyll fluorescence in the major light-harvesting complex of photosystem II: a systematic study of the effect of carotenoid structure.

    PubMed Central

    Phillip, D; Ruban, A V; Horton, P; Asato, A; Young, A J

    1996-01-01

    The role of carotenoids in quenching of chlorophyll fluorescence in the major light-harvesting complex of photosystem II has been studied with a view to understanding the molecular basis of the control of photoprotective nonradiative energy dissipation by the xanthophyll cycle in vivo. The control of chlorophyll fluorescence quenching in the isolated complex has been investigated in terms of the number of the conjugated double bonds for a series of carotenoids ranging from n = 5-19, giving an estimated first excited singlet state energy from 20,700 cm-1 to 10,120 cm-1. At pH 7.8 the addition of exogenous carotenoids with >=10 conjugated double bonds (including zeaxanthin) stimulated fluorescence quenching relative to the control with no added carotenoid, whereas those with n fluorescence. When quenching in the light-harvesting complex of photosystem II was induced by a lowering of pH to 5.5, carotenoids with n fluorescence quenching relative to the control. Of the 10 carotenoids tested, quenching induced by the addition of the tertiary amine compound, dibucaine, to isolated light-harvesting complex of photosystem II could only be reversed by violaxanthin. These results are discussed in terms of the two theories developed to explain the role of zeaxanthin and violaxanthin in nonphotochemical quenching of chlorophyll fluorescence. PMID:11607629

  6. Ultraviolet-visible light (UV-Vis)-reversible but fluorescence-irreversible chemosensor for copper in water and its application in living cells.

    PubMed

    Huo, Fang-Jun; Yin, Cai-Xia; Yang, Yu-Tao; Su, Jing; Chao, Jian-Bin; Liu, Dian-Sheng

    2012-03-06

    An ultraviolet-visible light (UV-Vis)-reversible but fluorescence-irreversible chemosensor was developed for the detection of copper. Coordination between the probe, 2-pyridylaldehyde fluorescein hydrazone (FHP), and Cu(2+) gave a reversible UV-Vis response, Storage of the probe-Cu complex resulted in hydrolytic cleavage of the N═C bond, which released the fluorophore (ring-opened fluorescein hydrazine) and gave irreversible fluorescence. Thus, FHP becomes a multifunctional chemosensor, and its reversibility can be controlled by the reaction time. Cu(2+) in living cells could be detected using FHP and general fluorescence methods.

  7. Primary production estimates from recordings of solar-stimulated fluorescence in the equatorial Pacific at 150 deg W

    NASA Technical Reports Server (NTRS)

    Stegmann, P. M.; Lewis, M. R.; Davis, C. O.; Cullen, J. J.

    1992-01-01

    Biological, optical, and hydrographical data were collected on the WEC88 cruise along 150 deg W and during a 6-day time-series station on the equator during February/March 1988. This area was characterized by a subsurface chlorophyll maximum (SCM), located at 50-70 m depth at the equator and descending down to 120-125 m at the north and south end of the transect. Highest primary production rates were near-surface and confined to the equatorial region and stations between 7 deg and 11 deg N. To determine the relationship between solar-stimulated fluorescence (centered at 683 nm wavelength) and primary production, a production-fluorescence model based on phytoplankton physiology and marine optics is described. Results of model calculations predict that there is a linear relation between production and fluorescence. A comparison between morning and midday measurements of the production-fluorescence relation showed that there was some difference between the two, whereas evening measurements, on the other hand, were distinctly different from the morning/midday ones. This seems to suggest that diurnal variations contribute significantly to variability in the quantum yield of photochemical processes. The ratio of the quantum yield of photosynthesis to the quantum yield of fluorescence ranged between 0.24 and 0.44 molC/Ein for all stations. The highest value for this ratio occurred at the equatorial stations, indicating that latitudinal variability could have an effect on the production-fluorescence relation.

  8. Analysis of complex samples using a portable multi-wavelength light emitting diode (LED) fluorescence spectrometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spectroscopic analysis of chemically complex samples often requires an increase n the dimensionality of the measured response surface. This often involves the measurement of emitted light intensities as functions of both wavelengths of excitation and emission resulting in the generation of an excita...

  9. Enhanced visualization of the bile duct via parallel white light and indocyanine green fluorescence laparoscopic imaging

    NASA Astrophysics Data System (ADS)

    Demos, Stavros G.; Urayama, Shiro

    2014-03-01

    Despite best efforts, bile duct injury during laparoscopic cholecystectomy is a major potential complication. Precise detection method of extrahepatic bile duct during laparoscopic procedures would minimize the risk of injury. Towards this goal, we have developed a compact imaging instrumentation designed to enable simultaneous acquisition of conventional white color and NIR fluorescence endoscopic/laparoscopic imaging using ICG as contrast agent. The capabilities of this system, which offers optimized sensitivity and functionality, are demonstrated for the detection of the bile duct in an animal model. This design could also provide a low-cost real-time surgical navigation capability to enhance the efficacy of a variety of other image-guided minimally invasive procedures.

  10. Use of time-resolved fluorescence spectroscopy to evaluate diagnostic value of collagen degradation products.

    PubMed

    Sikora, Joanna; Cyrankiewicz, Michał; Wybranowski, Tomasz; Ziomkowska, Blanka; Ośmiałowski, Borys; Obońska, Ewa; Augustyńska, Beata; Kruszewski, Stefan; Kubica, Jacek

    2015-05-01

    The concentration of collagen degradation products (CDPs) may reflect the process of left ventricular remodeling (LVR). The aim of this study was to evaluate the potential diagnostic usefulness of time-resolved fluorescence spectroscopy (TRFS) in assessment of CDPs. The preliminary experiment was designed to establish if CDPs’ characteristics might be visible by mean fluorescence lifetime (FLT) in determined conditions. The in vitro model of CDPs was prepared by conducting the hydrolysis of type III collagen. The FLT of samples was measured by the time-resolved spectrometer Life Spec II with the subnanosecond pulsed 360-nm EPLED diode. The FLTs were obtained by deconvolution analysis of the data using a multiexponential model of fluorescence decay. In order to determine the limit of traceability of CDPs, a comparison of different collagen/plasma ratio in samples was performed. The results of our study showed that the increase of added plasma to hydrolyzed collagen extended the mean FLT. Thus, the diagnosis of LVR based on measurements using TRFS is possible. However, it is important to point out the experiment was preliminary and further investigation in this field of research is crucial.

  11. Use of time-resolved fluorescence spectroscopy to evaluate diagnostic value of collagen degradation products

    NASA Astrophysics Data System (ADS)

    Sikora, Joanna; Cyrankiewicz, Michał; Wybranowski, Tomasz; Ziomkowska, Blanka; Ośmiałowski, Borys; Obońska, Ewa; Augustyńska, Beata; Kruszewski, Stefan; Kubica, Jacek

    2015-05-01

    The concentration of collagen degradation products (CDPs) may reflect the process of left ventricular remodeling (LVR). The aim of this study was to evaluate the potential diagnostic usefulness of time-resolved fluorescence spectroscopy (TRFS) in assessment of CDPs. The preliminary experiment was designed to establish if CDPs' characteristics might be visible by mean fluorescence lifetime (FLT) in determined conditions. The in vitro model of CDPs was prepared by conducting the hydrolysis of type III collagen. The FLT of samples was measured by the time-resolved spectrometer Life Spec II with the subnanosecond pulsed 360-nm EPLED diode. The FLTs were obtained by deconvolution analysis of the data using a multiexponential model of fluorescence decay. In order to determine the limit of traceability of CDPs, a comparison of different collagen/plasma ratio in samples was performed. The results of our study showed that the increase of added plasma to hydrolyzed collagen extended the mean FLT. Thus, the diagnosis of LVR based on measurements using TRFS is possible. However, it is important to point out the experiment was preliminary and further investigation in this field of research is crucial.

  12. Aggregation and fluorescence quenching of chlorophyll a of the light-harvesting complex II from spinach in vitro.

    PubMed

    Kirchhoff, Helmut; Hinz, Hans-Jürgen; Rösgen, Jörg

    2003-09-30

    The salt-induced aggregation of the light-harvesting complex (LHC) II isolated from spinach and its correlation with fluorescence quenching of chlorophyll a is reported. Two transitions with distinctly different properties were observed. One transition related to salt-induced fluorescence quenching takes place at low salt concentration and is dependent both on temperature and detergent concentration. This transition seems to be related to a change in the lateral microorganization of LHCII. The second transition occurs at higher salt concentration and involves aggregation. It is independent of temperature and of detergent at sub-cmc concentrations. During the latter transition the small LHCII sheets (approximately 100 nm in diameter) are stacked to form larger aggregates of approximately 3 microm diameter. Based on the comparison between the physical properties of the transition and theoretical models, direct and specific binding of cations can practically be ruled out as driving force for the aggregation. It seems that in vitro aggregation of LHCII is caused by a complex mixture of different effects such as dielectric and electrostatic properties of the solution and surface charges.

  13. Photon Production through Multi-step Processes Important in Nuclear Fluorescence Experiments

    SciTech Connect

    Hagmann, C; Pruet, J

    2006-10-26

    The authors present calculations describing the production of photons through multi-step processes occurring when a beam of gamma rays interacts with a macroscopic material. These processes involve the creation of energetic electrons through Compton scattering, photo-absorption and pair production, the subsequent scattering of these electrons, and the creation of energetic photons occurring as these electrons are slowed through Bremsstrahlung emission. Unlike single Compton collisions, during which an energetic photon that is scattered through a large angle loses most of its energy, these multi-step processes result in a sizable flux of energetic photons traveling at large angles relative to an incident photon beam. These multi-step processes are also a key background in experiments that measure nuclear resonance fluorescence by shining photons on a thin foil and observing the spectrum of back-scattered photons. Effective cross sections describing the production of backscattered photons are presented in a tabular form that allows simple estimates of backgrounds expected in a variety of experiments. Incident photons with energies between 0.5 MeV and 8 MeV are considered. These calculations of effective cross sections may be useful for those designing NRF experiments or systems that detect specific isotopes in well-shielded environments through observation of resonance fluorescence.

  14. Light element production by low energy nuclei from massive stars

    NASA Technical Reports Server (NTRS)

    Vangioni-Flam, E.; Casse, M.; Ramaty, R.

    1997-01-01

    The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.

  15. Ubiquitous Autofragmentation of Fluorescent Proteins Creates Abundant Defective Ribosomal Products (DRiPs) for Immunosurveillance*

    PubMed Central

    Wei, Jiajie; Gibbs, James S.; Hickman, Heather D.; Cush, Stephanie S.; Bennink, Jack R.; Yewdell, Jonathan W.

    2015-01-01

    Green fluorescent protein (GFP) and other fluorescent proteins are essential tools for biological research. When fused to peptides or proteins as a reporter, GFP enables localization and quantitation of gene products in otherwise unmanipulated live cells or organisms. We previously reported that a sizable fraction of nascent GFP is post-translationally converted into a 20-kDa Triton X-100-insoluble proteasome substrate (Qian, S. B., Princiotta, M. F., Bennink, J. R., and Yewdell, J. W. (2006) J. Biol. Chem. 281, 392–400; Dolan, B. P., Li, L., Veltri, C. A., Ireland, C. M., Bennink, J. R., and Yewdell, J. W. (2011) J. Immunol. 186, 2065–2072). Here, we show that a similarly sized fragment is generated by all GFP and red fluorescent protein family members we examined. We demonstrate that fragmentation is a by-product of GFP chromophore rearrangement. A non-rearranging GFP mutant fails to fragment and generates diminished levels of Kb-SIINFEKL complexes when SIINFEKL is genetically fused to either the C- or N-terminal domains of GFP fusion proteins. Instructively, another fragmenting GFP mutant that cannot create the functional chromophore but still generates fragments also demonstrates diminished Kb-SIINFEKL generation. However, the mutant and wild-type fragments differ fundamentally in that wild-type fragments are rapidly liberated from the intact molecule and degraded quickly, accounting for increased Kb-SIINFEKL generation. In the fragmenting mutant, the fragments are generated slowly and remain associated, likely in a native conformation based on their original structural description (Barondeau, D. P., Kassmann, C. J., Tainer, J. A., and Getzoff, E. D. (2006) J. Am. Chem. Soc. 128, 4685–4693). The wild-type GFP fragments represent the first biochemically defined natural defective ribosomal products to contribute peptides for immunosurveillance, enabling quantitation of peptide generation efficiency from this source of defective ribosomal products. More

  16. Ultrasensitive detection of waste products in water using fluorescence emission cavity-enhanced spectroscopy.

    PubMed

    Bixler, Joel N; Cone, Michael T; Hokr, Brett H; Mason, John D; Figueroa, Eleonora; Fry, Edward S; Yakovlev, Vladislav V; Scully, Marlan O

    2014-05-20

    Clean water is paramount to human health. In this article, we present a technique for detection of trace amounts of human or animal waste products in water using fluorescence emission cavity-enhanced spectroscopy. The detection of femtomolar concentrations of urobilin, a metabolic byproduct of heme metabolism that is excreted in both human and animal waste in water, was achieved through the use of an integrating cavity. This technique could allow for real-time assessment of water quality without the need for expensive laboratory equipment.

  17. Light Sheet Fluorescence Microscopy of Plant Roots Growing on the Surface of a Gel

    PubMed Central

    von Wangenheim, Daniel; Hauschild, Robert; Friml, Jiří

    2017-01-01

    One of the key questions in understanding plant development is how single cells behave in a larger context of the tissue. Therefore, it requires the observation of the whole organ with a high spatial- as well as temporal resolution over prolonged periods of time, which may cause photo-toxic effects. This protocol shows a plant sample preparation method for light-sheet microscopy, which is characterized by mounting the plant vertically on the surface of a gel. The plant is mounted in such a way that the roots are submerged in a liquid medium while the leaves remain in the air. In order to ensure photosynthetic activity of the plant, a custom-made lighting system illuminates the leaves. To keep the roots in darkness the water surface is covered with sheets of black plastic foil. This method allows long-term imaging of plant organ development in standardized conditions. PMID:28190052

  18. Numerical modelling and in vivo analysis of fluorescent and laser light backscattered from glial brain tumors

    NASA Astrophysics Data System (ADS)

    Savelieva, Tatiana A.; Kalyagina, Nina A.; Kholodtsova, Maria N.; Loschenov, Victor B.; Goryainov, Sergey A.; Potapov, Aleksander A.

    2012-03-01

    Brain glial tumors have peculiar features of the perifocal region extension, characterized by its indistinct area, which complicates determination of the borders for tissue resection. In the present study filter-reduced back-scattered laser light signals, compared to the data from mathematical modeling, were used for description of the brain white matter. The simulations of the scattered light distributions were performed in a Monte Carlo program using scattering and absorption parameters of the different grades of the brain glial tumors. The parameters were obtained by the Mie calculations for three main types of scatterers: myelinated axon fibers, cell nuclei and mitochondria. It was revealed that diffuse-reflected light, measured at the perifocal areas of the glial brain tumors, shows a significant difference relative to the signal, measured at the normal tissue, which signifies the possibility to provide diagnostically useful information on the tissue state, and to determine the borders of the tumor, thus to reduce the recurrence appearance. Differences in the values of ratios of diffuse reflectance from active growth parts of tumors and normal white matter can be useful for determination of the degree of tumor progress during the spectroscopic analysis.

  19. ultraLM and miniLM: Locator tools for smart tracking of fluorescent cells in correlative light and electron microscopy

    PubMed Central

    2016-01-01

    In-resin fluorescence (IRF) protocols preserve fluorescent proteins in resin-embedded cells and tissues for correlative light and electron microscopy, aiding interpretation of macromolecular function within the complex cellular landscape. Dual-contrast IRF samples can be imaged in separate fluorescence and electron microscopes, or in dual-modality integrated microscopes for high resolution correlation of fluorophore to organelle. IRF samples also offer a unique opportunity to automate correlative imaging workflows. Here we present two new locator tools for finding and following fluorescent cells in IRF blocks, enabling future automation of correlative imaging. The ultraLM is a fluorescence microscope that integrates with an ultramicrotome, which enables ‘smart collection’ of ultrathin sections containing fluorescent cells or tissues for subsequent transmission electron microscopy or array tomography. The miniLM is a fluorescence microscope that integrates with serial block face scanning electron microscopes, which enables ‘smart tracking’ of fluorescent structures during automated serial electron image acquisition from large cell and tissue volumes. PMID:28090593

  20. Fluorescent optical position sensor

    DOEpatents

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  1. Quantification of zinc-porphyrin in dry-cured ham products by spectroscopic methods Comparison of absorption, fluorescence and X-ray fluorescence spectroscopy.

    PubMed

    Laursen, Kristoffer; Adamsen, Christina E; Laursen, Jens; Olsen, Karsten; Møller, Jens K S

    2008-03-01

    Zinc-protoporphyrin (Zn-pp), which has been identified as the major pigment in certain dry-cured meat products, was extracted with acetone/water (75%) and isolated from the following meat products: Parma ham, Iberian ham and dry-cured ham with added nitrite. The quantification of Zn-pp by electron absorption, fluorescence and X-ray fluorescence (XRF) spectroscopy was compared (concentration range used [Zn-pp]=0.8-9.7μM). All three hams were found to contain Zn-pp, and the results show no significant difference among the content of Zn-pp quantified by fluorescence, absorbance and X-ray fluorescence spectroscopy for Parma ham and Iberian ham. All three methods can be used for quantification of Zn-pp in acetone/water extracts of different ham types if the content is higher than 1.0ppm. For dry-cured ham with added nitrite, XRF was not applicable due to the low content of Zn-pp (<0.1ppm). In addition, XRF spectroscopy provides further information regarding other trace elements and can therefore be advantageous in this aspect. This study also focused on XRF determination of Fe in the extracts and as no detectable Fe was found in the three types of ham extracts investigated (limit of detection; Fe⩽1.8ppm), it allows the conclusion that iron containing pigments, e.g., heme, do not contribute to the noticeable red colour observed in some of the extracts.

  2. Flavonoid content in fresh, home-processed, and light-exposed onions and in dehydrated commercial onion products.

    PubMed

    Lee, Seung Un; Lee, Jong Ha; Choi, Suk Hyun; Lee, Jin Shik; Ohnisi-Kameyama, Mayumi; Kozukue, Nobuyuki; Levin, Carol E; Friedman, Mendel

    2008-09-24

    Onion plants synthesize flavonoids as protection against damage by UV radiation and by intracellular hydrogen peroxide. Because flavonoids also exhibit health-promoting effects in humans, a need exists to measure their content in onions and in processed onion products. To contribute to the knowledge about the levels of onion flavonoids, HPLC and LC-MS were used to measure levels of seven quercetin and isorhamnetin glucosides in four Korean commercial onion bulb varieties and their distribution within the onion, in scales of field-grown onions exposed to home processing or to fluorescent light and in 16 commercial dehydrated onion products sold in the United States. Small onions had higher flavonoid content per kilogram than large ones. There was a graduated decrease in the distribution of the flavonoids across an onion bulb from the first (outside) to the seventh (innermost) scale. Commercial, dehydrated onion products contained low amounts or no flavonoids. Losses of onion flavonoids subjected to "cooking" (in percent) ranged as follows: frying, 33; sauteing, 21; boiling, 14-20; steaming, 14; microwaving, 4; baking, 0. Exposure to fluorescent light for 24 and 48 h induced time-dependent increases in the flavonoid content. The results extend the knowledge about the distribution of flavonoids in fresh and processed onions.

  3. Status of Solid State Lighting Product Development and Future Trends for General Illumination.

    PubMed

    Katona, Thomas M; Pattison, P Morgan; Paolini, Steve

    2016-06-07

    After decades of research and development on fabrication of efficient light-emitting diodes (LEDs) throughout the visible spectrum, LED-based lighting has reached unparalleled performance with respect to energy efficiency and has become the light source for virtually all new lighting products being designed today. The development of the core light sources and their subsequent integration into lighting systems continue to present unique challenges and opportunities for product designers. We review these systems and the current development status, as well as provide context for the trends in solid state lighting that are leading to the development of value-added lighting solutions that extend the domain of lighting beyond light generation, into fields as diverse as communications, healthcare, and agricultural production.

  4. Fluorometric flow-immunoassay for alkylphenol polyethoxylates on a microchip containing a fluorescence detector comprised of an organic light emitting diode and an organic photodiode.

    PubMed

    Liu, Rong; Ishimatsu, Ryoichi; Yahiro, Masayuki; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko

    2015-03-01

    A compact fluorescence detector was constructed on a microchip from an organic light emitting diode (OLED) as the light source and an organic photodiode (OPD) as the photo-detector and was used in an immunoassay for alkylphenol polyethoxylates (APE). The OLED based on a terbium complex emitted a sharp light at the main wavelength of 546 nm with a full width at half maximum of 9 nm. The incident photo-to-current conversion efficiency (IPCE) of the OPD fabricated with Fullerene 70 (C70) and tris[4-(5-phenylthiopen-2-yl)phenyl]-amine (TPTPA) was approximately 44% for light at a wavelength of 586 nm. The performance of the fluorescence detector was evaluated for the determination of resorufin (λ(em)=586 nm) and the photocurrent of the OPD due to the fluorescence of resorufin was proportional to the concentration of resorufin in the range from 0 to 18 µM with a detection limit (S/N=3) of 0.6 µM. The fluorescence detector was successfully utilized in a competitive enzyme-linked immunosorbent assay for APE, where an anti-APE antibody was immobilized on the surface of the channel of the Polydimethylsiloxane (PDMS) microchip or on the surface of magnetic microbeads. After an immunoreaction with a sample solution of APE containing a horse radish peroxidase (HRP)-labeled APE, the fluorescence of resorufin generated just after introduction of a mixed solution of Amplex Red and H2O2 was measured using the fluorescence detector. The calibration curve for the photocurrent signals of the OPD due to the fluorescence of resorufin against the logarithmic concentration of APE was sigmoidal in shape. The detection limits defined as IC80 were ca. 1 ppb and ca. 2 ppb, respectively, for the methods using the anti-APE antibody immobilized on the surface of the microchannel and in the case where the antibody was immobilized on the surface of magnetic microbeads.

  5. Comparison of light and fluorescence microscopy for xylem analysis in tomato pedicels during fruit development.

    PubMed

    Rancić, D; Quarrie, S Pekić; Terzić, M; Savić, S; Stikić, R

    2008-12-01

    The xylem hydraulic connection between shoot and fruits has previously been investigated, but contradictory conclusions were drawn about the presence of a flow resistance barrier in the pedicel. In this paper we were studying effect of the drought on the functional xylem vessels in the pedicels of tomato fruit. Commercial tomato genotype was grown in cabinet conditions under two watering regimes (full and deficit irrigation). An aqueous solution of eosin Y were used to visualize the path of water movement through tomato fruit pedicel and fluorescence microscopy observations were done on transversal and longitudinal sections. Dye uptake studies suggested that in well watered plants and in plants exposed to drought, a large majority of xylem vessels are not functional in water transport. Reduced-irrigation treatment significantly altered number and width of functional xylem elements in the fruit pedicel, especially in the abscission zone. This indicates that drought modifies xylem architecture and, thus, environmentally produced change in the hydraulic property of pedicel may affect fruit development.

  6. Lighting Up the Force: Investigating Mechanisms of Mechanotransduction Using Fluorescent Tension Probes

    PubMed Central

    Jurchenko, Carol

    2015-01-01

    The ability of cells to sense the physical nature of their surroundings is critical to the survival of multicellular organisms. Cellular response to physical cues from adjacent cells and the extracellular matrix leads to a dynamic cycle in which cells respond by remodeling their local microenvironment, fine-tuning cell stiffness, polarity, and shape. Mechanical regulation is important in cellular development, normal morphogenesis, and wound healing. The mechanisms by which these finely balanced mechanotransduction events occur, however, are not well understood. In large part, this is due to the limited availability of tools to study molecular mechanotransduction events in live cells. Several classes of molecular tension probes have been recently developed which are rapidly transforming the study of mechanotransduction. Molecular tension probes are primarily based on fluorescence resonance energy transfer (FRET) and report on piconewton scale tension events in live cells. In this minireview, we describe the two main classes of tension probes, genetically encoded tension sensors and immobilized tension sensors, and discuss the advantages and limitations of each type. We discuss future opportunities to address major biological questions and outline the challenges facing the next generation of molecular tension probes. PMID:26031334

  7. Photosynthetic acclimation to light in woody and herbaceous species: a comparison of leaf structure, pigment content and chlorophyll fluorescence characteristics measured in the field.

    PubMed

    Hallik, L; Niinemets, U; Kull, O

    2012-01-01

    Acclimation of foliage photosynthetic properties occurs with varying time kinetics, but structural, chemical and physiological factors controlling the kinetics of acclimation are poorly understood, especially in field environments. We measured chlorophyll fluorescence characteristics, leaf total carotenoid (Car), chlorophyll (Chl) and nitrogen (N) content and leaf dry mass per area (LMA) along vertical light gradients in natural canopies of the herb species, Inula salicina and Centaurea jacea, and tree species, Populus tremula and Tilia cordata, in the middle of the growing season. Presence of stress was assessed on the basis of night measurements of chlorophyll fluorescence. Our aim was to compare the light acclimation of leaf traits, which respond to light availability at long (LMA and N), medium (Chl a/b ratio, Car/Chl ratio) and short time scales (fluorescence characteristics). We found that light acclimation of nitrogen content per unit leaf area (N(area)), chlorophyll content per unit dry mass (Chl(mass)) and Chl/N ratio were related to modifications in LMA. The maximum PSII quantum yield (F(v) /F(m)) increased with increasing growth irradiance in I. salicina and P. tremula but decreased in T. cordata. Leaf growth irradiance, N content and plant species explained the majority of variability in chlorophyll fluorescence characteristics, up to 90% for steady-state fluorescence yield, while the contribution of leaf total carotenoid content was generally not significant. Chlorophyll fluorescence characteristics did not differ strongly between growth forms, but differed among species within a given growth form. These data highlight that foliage acclimation to light is driven by interactions between traits with varying time kinetics.

  8. Market Trial: Selling Off-Grid Lighting Products in Rural Kenya

    SciTech Connect

    Tracy, Jennifer; Alstone, Peter; Jacobson, Arne; Mills, Evan

    2010-06-21

    In this study, we performed a market trial of off-grid LED lighting products in Maai Mahiu, arural Kenyan town. Our goals were to assess consumer demand and consumer preferences with respect to off-grid lighting systems and to gain feedback from off-grid lighting users at the point of purchase and after they have used to products for some time.

  9. Fluorescent minerals - A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments

    NASA Astrophysics Data System (ADS)

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  10. Fluorescent minerals--A potential source of UV protection and visible light for the growth of green algae and cyanobacteria in extreme cosmic environments.

    PubMed

    Omairi, Tareq; Wainwright, Milton

    2015-07-01

    We propose that green algae (Chlorella variabilis and Dunaliella tertiolecta) and cyanobacteria (Synechococcus elongatus and Nostoc commune) can grow inside fluorescent rock minerals which convert damaging UV light to visible light, thereby allowing these organisms to survive and thrive in UV-rich environments without (or with limited) visible light, which would otherwise be inimical to them. The four microorganisms were incubated inside fluorescent rocks composed of fluorite, calcite and pyrite. The resultant growth was then measured following exposure to UV radiation, with the use of optical density and measurement of chlorophyll concentration. Results show that the microorganisms were shielded from harmful UV in these semi-transparent rocks, while at the same time benefiting from the fact that the minerals converted UV to visible light; this have been shown by a statistically significant increase in their growth, which although lower than when the cells were incubated in sunlight, was significantly higher than in controls incubated in the dark.

  11. Breakthrough of ultraviolet light from various brands of fluorescent lamps: lethal effects on DNA repair-defective bacteria.

    PubMed

    Hartman, P E; Biggley, W H

    1996-01-01

    In a comparative study of 17 pairs of 15 W fluorescent lamps intended for use in homes and purchased in local stores, we detect over 10-fold differences in UVB + UVC emissions between various lamps. This breakthrough of ultraviolet (UV) light is in part correlated with ability of lamps to kill DNA repair-defective recA-uvrB- Salmonella. Relative proficiency of lamps in eliciting photoreactivation of UV-induced DNA lesions also plays a prominent role in the relative rates of bacterial inactivation by emissions from different lamps. Lamps made in Chile, such as Philips brand lamps and one type of General Electric lamp, produce far less UVB + UVC and fail to kill recA-uvrB- bacteria. In contrast, all tested lamps manufactured in the USA, Hungary, and Japan exhibit readily observed deleterious biological effects. When an E. coli recA-uvrB-phr- (photolyase-negative) triple mutant is used for assay, lethal radiations are detected from all lamps, and single-hit exponential inactivation rates rather closely correlate to amount of directly measured UVB + UVC output of each pair of lamps. Although all lamps tested may meet international and United States standards for radiation safety, optimal practices in lamp manufacture are clearly capable of decreasing human exposure to indoor UV light.

  12. Breakthrough of ultraviolet light from various brands of fluorescent lamps: Lethal effects on DNA repair-defective bacteria

    SciTech Connect

    Hartman, P.E.; Biggley, W.H.

    1996-12-31

    In a comparative study of 17 pairs of 15 W fluorescent lamps intended for use in homes and purchased in local stores, we detect over 10-fold differences in UVB + UVC emissions between various lamps. This breakthrough of ultraviolet (UV) light is in part correlated with ability of lamps to kill DNA repair-defective recA{sup {minus}}uvrB{sup {minus}} Salmonella. Relative proficiency of lamps in eliciting photoreactivation of UV-induced DNA lesions also plays a prominent role in the relative rates of bacterial inactivation by emissions from different lamps. Lamps made in Chile, such as Phillips brand lamps and one type of General Electric lamp, produce far less UVB + UVC and fail to kill recA{sup {minus}} uvrB{sup {minus}} bacteria. In contrast, all tested lamps manufactured in the USA, Hungary, and Japan exhibit readily observed deleterious biological effects. When an E. coli recA{sup {minus}} uvrB{sup {minus}} phr{sup {minus}} (photolyase-negative) triple mutant is used for assay, lethal radiations are detected from all lamps, and single-hit exponential inactivation rates rather closely correlate to amount of directly measured UVB + UVC output of each pair of lamps. Although all lamps tested may meet international and Unite States standards for radiation safely, optimal practices in lamp manufacture are clearly capable of decreasing human exposure to indoor UV light. 38 refs., 3 figs., 1 tab.

  13. Fluorescent light mediated a green synthesis of silver nanoparticles using the protein extract of weaver ant larvae.

    PubMed

    Khamhaengpol, Arunrat; Siri, Sineenat

    2016-10-01

    Alternative to crude plant extracts, a crude protein extract derived from animal cells is one of the potential sources of biomolecules for mediating a reduction of silver ions and a formation of silver nanoparticles (AgNPs) under a mild condition, which very few works have been reported. This work demonstrated a use of the protein extract of weaver ant larvae as a bio-facilitator for a simple, green synthesis of AgNPs under fluorescent light at room temperature. The protein extract of weaver ant larvae exhibited the reducing and antioxidant activities, which assisted a formation of AgNPs in the reaction containing only silver nitrate under light exposure. Transmission electron microscopy images revealed the dispersed, spherical AgNPs with an average size of 7.87±2.54nm. The maximum surface plasmon resonance (SPR) band of the synthesized AgNPs was at 435nm. The energy-dispersive X-ray analysis revealed that silver was a major element of the particles. The identity of AgNPs was confirmed by X-ray diffraction pattern, selected area electron diffraction and high resolution transmission electron microscopy analyses, which demonstrated the planes of face centered cubic silver. The synthesized AgNPs showed antibacterial activity against both Escherichia coli and Staphylococcus aureus with the minimum bactericidal concentration (MBC) values equally at 250μg/ml, suggesting their potential application as an effective antibacterial agent.

  14. Blue organic light-emitting diodes realizing external quantum efficiency over 25% using thermally activated delayed fluorescence emitters.

    PubMed

    Miwa, Takuya; Kubo, Shosei; Shizu, Katsuyuki; Komino, Takeshi; Adachi, Chihaya; Kaji, Hironori

    2017-03-21

    Improving the performance of blue organic light-emitting diodes (OLEDs) is needed for full-colour flat-panel displays and solid-state lighting sources. The use of thermally activated delayed fluorescence (TADF) is a promising approach to efficient blue electroluminescence. However, the difficulty of developing efficient blue TADF emitters lies in finding a molecular structure that simultaneously incorporates (i) a small energy difference between the lowest excited singlet state (S1) and the lowest triplet state (T1), ΔE ST, (ii) a large oscillator strength, f, between S1 and the ground state (S0), and (iii) S1 energy sufficiently high for blue emission. In this study, we develop TADF emitters named CCX-I and CCX-II satisfying the above requirements. They show blue photoluminescence and high triplet-to-singlet up-conversion yield. In addition, their transition dipole moments are horizontally oriented, resulting in further increase of their electroluminescence efficiency. Using CCX-II as an emitting dopant, we achieve a blue OLED showing a high external quantum efficiency of 25.9%, which is one of the highest EQEs in blue OLEDs reported previously.

  15. Quantification of Fungal DNA by Using Fluorescence Resonance Energy Transfer and the Light Cycler System

    PubMed Central

    Loeffler, Juergen; Henke, Norbert; Hebart, Holger; Schmidt, Diethard; Hagmeyer, Lars; Schumacher, Ulrike; Einsele, Hermann

    2000-01-01

    The Light Cycler technique combines rapid in vitro amplification of DNA in glass capillaries with real-time species determination and quantification of DNA load. We have established a quantitative PCR protocol for two clinically important pathogens, Candida albicans and Aspergillus fumigatus. The sensitivity of the assay was comparable to those of previously described PCR protocols (5 CFU/ml). Specific detection of C. albicans and A. fumigatus could be achieved. The assay showed a high reproducibility of 96 to 99%. The assay was linear in a range between 101 and 104 Aspergillus conidia. As capillaries do not have to be reopened for post-PCR analysis, the risk of carryover contaminations could be minimized. The Light Cycler allowed quantification of the fungal loads in a limited number of clinical specimens from patients with hematological malignancies and histologically proven invasive fungal infections. Five of nine positive samples had fungal loads between 5 and 10 CFU/ml of blood, two of nine positive samples had fungal loads between 10 and 100 CFU/ml of blood, and two of nine samples had fungal loads of more than 100 CFU/ml of blood. All samples were also found to be PCR positive by PCR–enzyme-linked immunosorbent assay analysis. PMID:10655350

  16. Self-assembly-induced far-red/near-infrared fluorescence light-up for detecting and visualizing specific protein-Peptide interactions.

    PubMed

    Wang, Huaimin; Liu, Jie; Han, Aitian; Xiao, Nannan; Xue, Zhaosheng; Wang, Gang; Long, Jiafu; Kong, Deling; Liu, Bin; Yang, Zhimou; Ding, Dan

    2014-02-25

    Understanding specific protein-peptide interactions could offer a deep insight into the development of therapeutics for many human diseases. In this work, we designed and synthesized a far-red/near-infrared (FR/NIR) fluorescence light-up probe (DBT-2EEGWRESAI) by simply integrating two tax-interacting protein-1 (TIP-1)-specific peptide ligands (EEGWRESAI) with one 4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole (DBT) unit. We first demonstrated that DBT is an environment-sensitive fluorophore with FR/NIR fluorescence due to its strong charge transfer character in the excited state. Thanks to the environmental sensitivity of DBT, the probe DBT-2EEGWRESAI is very weakly fluorescent in aqueous solution but lights up its fluorescence when the probe specifically binds to TIP-1 protein or polyprotein (ULD-TIP-1 tetramer). It is found that the DBT-2EEGWRESAI/TIP-1 protein and the DBT-2EEGWRESAI/ULD-TIP-1 tetramer could self-assemble into spherical nanocomplexes and a nanofiber network, respectively, which lead to probe fluorescence turn-on through providing DBT with a hydrophobic microenvironment. By virtue of the self-assembly-induced FR/NIR fluorescence turn-on, DBT-2EEGWRESAI can detect and visualize specific protein/polyprotein-peptide interactions in both solution and live bacteria in a high contrast and selective manner.

  17. Identification of Daqingye and Banlangen including crude drugs and decoction dregs from three plant species by normal light and fluorescence microscopy.

    PubMed

    Xiaojing, Wan; Liang, Zhitao; Chen, Hu-Biao; Zhao, Zhongzhen; Li, Ping

    2013-08-01

    Daqingye and Banlangen are commonly used Chinese medicinal materials derived from the leaves and roots of Isatis indigotica Fort., respectively, which clinical effects have been confirmed by many studies in recent years. However, many problems have arisen concerning the quality and identity of materials sold in the market under these two names. Thus, the identification of Daqingye and Banlangen has drawn public attention. In this work, transverse sections of Daqingye and Banlangen from I. indigotica Fort. and two easily confused species, namely Baphicacanthus cusia (Nees) Bremek. and Clerodendrum cyrtophyllum Turcz., were investigated with normal light and fluorescence microscopy. The distinguishing features were 7-9 vascular bundles, cystoliths and nonglandular hairs in the leaves of I. indigotica, B. cusia, and C. cyrtophyllum, respectively. The Banlangen could be distinguished according to the characteristics of parenchymous cells, cystoliths, and stone cells. Moreover, the fluorescence features of Daqingye and Banlangen investigated in this study can provide direct points for differentiating those samples. Importantly, whether the crude drugs were decocted could be easily identified by their different fluorescence features, which can ensure their quality in clinical application. This is the first report to distinguish the three species that are commonly found in the market sold as Daqingye and Banlangen by normal light and fluorescence microscopy. This work indicates that the combination of normal light and fluorescence microscopy could be powerful, convenient, and economical for authenticating Daqingye and Banlangen from the three species, including crude drugs and decoction dregs.

  18. New global observations of the terrestrial carbon cycle from GOSAT: Patterns of plant fluorescence with gross primary productivity

    NASA Astrophysics Data System (ADS)

    Frankenberg, Christian; Fisher, Joshua B.; Worden, John; Badgley, Grayson; Saatchi, Sassan S.; Lee, Jung-Eun; Toon, Geoffrey C.; Butz, André; Jung, Martin; Kuze, Akihiko; Yokota, Tatsuya

    2011-09-01

    Our ability to close the Earth's carbon budget and predict feedbacks in a warming climate depends critically on knowing where, when and how carbon dioxide is exchanged between the land and atmosphere. Terrestrial gross primary production (GPP) constitutes the largest flux component in the global carbon budget, however significant uncertainties remain in GPP estimates and its seasonality. Empirically, we show that global spaceborne observations of solar induced chlorophyll fluorescence - occurring during photosynthesis - exhibit a strong linear correlation with GPP. We found that the fluorescence emission even without any additional climatic or model information has the same or better predictive skill in estimating GPP as those derived from traditional remotely-sensed vegetation indices using ancillary data and model assumptions. In boreal summer the generally strong linear correlation between fluorescence and GPP models weakens, attributable to discrepancies in savannas/croplands (18-48% higher fluorescence-based GPP derived by simple linear scaling), and high-latitude needleleaf forests (28-32% lower fluorescence). Our results demonstrate that retrievals of chlorophyll fluorescence provide direct global observational constraints for GPP and open an entirely new viewpoint on the global carbon cycle. We anticipate that global fluorescence data in combination with consolidated plant physiological fluorescence models will be a step-change in carbon cycle research and enable an unprecedented robustness in the understanding of the current and future carbon cycle.

  19. Relationship between the Fluorescence Lifetime of Chlorophyll 'a' and Primary Productivity within the Mississippi River Plume and Adjacent Shelf Region

    NASA Technical Reports Server (NTRS)

    Hall, Callie; Miller, Richard L.; Fernandez, Salvador M.; McKee, Brent A.

    2000-01-01

    In situ measurements of chlorophyll fluorescence intensity have been widely used to estimate phytoplankton biomass. However, because the fluorescence quantum yield of chlorophyll a in vivo can be highly variable, measurements of chlorophyll fluorescence intensity cannot be directly correlated with phytoplankton biomass and do not provide information on the physiological state of the phytoplankton under study. Conversely, lifetime-based measurements of chlorophyll fluorescence provide a framework in which photosynthetic rates of phytoplankton can be analyzed according to phytoplankton physiology. Along with the measurement of primary production and ambient nutrient concentrations within the Mississippi River plume in the northern Gulf of Mexico, phytoplankton fluorescence lifetimes were measured using a Fluorescence Lifetime Phytoplankton Analyzer (developed under a NASA Small Business Innovative Research contract to Ciencia, Inc.). Variability of fluorescence lifetimes within the plume can be used as a background from which to interpret variations in the maximum quantum yield of photochemistry. The extent to which nutrient and effluent loading in this dynamic coastal area affect the photosynthetic performance of phytoplankton will be presented as a function of phytoplankton fluorescence lifetimes.

  20. 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.

  1. Photocatalytic oxidation removal of Hg0 using ternary Ag/AgI-Ag2CO3 hybrids in wet scrubbing process under fluorescent light

    NASA Astrophysics Data System (ADS)

    Zhang, Anchao; Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao; Xiang, Jun

    2017-01-01

    A series of ternary Ag/AgI-Ag2CO3 photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg0 removal in a wet scrubbing reactor. The hybrids were characterized by N2 adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg0 removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg0 removal. NO exhibited significant effect on Hg0 removal in comparison to SO2. Among these ternary Ag/AgI-Ag2CO3 hybrids, Ag/AgI(0.1)-Ag2CO3 showed the highest Hg0 removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag2CO3 and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag0 NPs). The trapping studies of reactive radicals showed that the superoxide radicals (rad O2-) may play a key role in Hg0 removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg0 removal over Ag/AgI(0.1)-Ag2CO3 hybrid under fluorescent light was proposed.

  2. Single-wavelength-controlled in situ dynamic super-resolution fluorescence imaging for block copolymer nanostructures via blue-light-switchable FRAP.

    PubMed

    Gong, Wen-Liang; Yan, Jie; Zhao, Ling-Xi; Li, Chong; Huang, Zhen-Li; Tang, Ben Zhong; Zhu, Ming-Qiang

    2016-11-02

    Photoswitchable fluorophores are promising in single-molecule optical devices and super-resolution fluorescence imaging, especially in single-molecule photo-activated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM). However, the scarcity of current photoswitchable fluorophores stimulates researchers to develop complicated optical systems and processing software, in accordance with the limited photoswitchable fluorescent proteins and organic fluorophores. Previous efforts to develop synthetic photoswitchable fluorophores have exhibited their promising potential in super-resolution fluorescence imaging. Here, we have designed and synthesized a fluorescence molecular switch with reversible green emission, a napthalimide-hexaarylbiimidazole conjugate (NI-N-HABI), which exhibits strong fluorescence in the emissive state, with fast thermal fading of the photochromism and spontaneous fluorescence recovery after photobleaching (FRAP) induced by blue-light. The photoswitchable fluorophore enables the red-edge wavelength of the optical response to red-shift from the initial near-UV region at less than 400 nm, to 500 nm. The relatively fast fading speed of NI-N-HABI and its sensitivity to longer blue-light irradiation (400-500 nm) have allowed simplification of the optical microscopic system from a two-wavelength laser source to a single-wavelength laser. We applied NI-N-HABI in single-wavelength-controlled in situ dynamic super-resolution fluorescence imaging for the self-assembly and solvent annealing of amphiphilic block polymers, with 50 nm of optical resolution. Single-wavelength-controlled dynamic super-resolution fluorescence imaging facilitates nanoscale optical visualization for the dynamic physical and chemical fluctuation processes of stimuli-responsive nanostructures.

  3. Design and evaluation of capillary coupled with optical fiber light-emitting diode induced fluorescence detection for capillary electrophoresis.

    PubMed

    Ji, Hongyun; Li, Meng; Guo, Lihong; Yuan, Hongyan; Wang, Chunling; Xiao, Dan

    2013-09-01

    A new detector, capillary coupled with optical fiber LED-induced fluorescence detector (CCOF-LED-IFD, using CCOF for short), is introduced for CE. The strategy of the present work was that the optical fiber and separation capillary were, in the parallel direction, fastened in a fixation capillary with larger inner diameter. By employing larger inner diameter, the fixation capillary allowed the large diameter of the optical fiber to be inserted into it. By transmitting an enhanced excitation light through the optical fiber, the detection sensitivity was improved. The advantages of the CCOF-CE system were validated by the detection of riboflavin, and the results were compared to those obtained by the in-capillary common optical fiber LED-induced fluorescence detector (IC-COF-LED-IFD, using COF for short). The LODs of CCOF-CE and COF-CE were 0.29 nM and 11.0 nM (S/N = 3), respectively. The intraday (n = 6) repeatability and interday (n = 6) reproducibility of migration time and corresponding peak area for both types of CE were all less than 1.10 and 3.30%, respectively. The accuracy of the proposed method was judged by employing standard addition method, and recoveries obtained were in the range of 98.0-102.4%. The results indicated that the sensitivity of the proposed system was largely improved, and that its reproducibility and accuracy were satisfactory. The proposed system was successfully applied to separate and determine riboflavin in real sample.

  4. Enamel demineralization and remineralization under plaque fluid-like conditions: a quantitative light-induced fluorescence study.

    PubMed

    Lippert, F; Butler, A; Lynch, R J M

    2011-01-01

    The present study investigated de- and remineralization in enamel lesions under plaque fluid (PF)-like conditions using quantitative light-induced fluorescence (QLF). Preformed lesions were exposed to partially saturated lactic acid solutions, varying in pH and fluoride concentration ([F]) based on a 5 × 3 factorial study design (0/0.1/0.5/1.5/4 ppm F; pH 4.9/5.2/5.5). Average fluorescence loss (ΔF) was monitored for 11 days. Subsequently, lesions were demineralized in a partially saturated acetic acid solution for two 24-hour periods. Data were analyzed using repeated measures analysis of covariance. Lesions exposed to PF at 4 ppm F and pH 5.5 showed not only the most remineralization (ΔΔF = 28.2 ± 14.0%) for all groups after 11 days, but also the most demineralization (ΔΔF = -19.3 ± 13.5%) after subsequent acetic acid exposure. Increased [F] resulted in more remineralization, regardless of pH. Higher pH values resulted in more remineralization. No remineralization was observed in lesions exposed to F-free solutions, regardless of pH. Remineralization was noticeable under the following conditions: pH 4.9 - [F] = 4 ppm, pH 5.2 - [F] ≥ 1.5 ppm, and pH 5.5 - [F] ≥ 0.5 ppm. Overall, [F] had a stronger effect on remineralization than pH. Subsequent demineralization showed that little protection was offered by PF-like solutions, and further demineralization compared with baseline was observed on lesions not remineralized initially. [F] had a stronger effect on net mineral change than pH. The present study has shown that QLF is a valuable tool in studying lesion de- and remineralization under PF-like conditions, where [F] was shown to be more important than pH.

  5. Inactivation of Escherichia coli on anatase and rutile nanoparticles using UV and fluorescent light

    SciTech Connect

    Caratto, V.; Aliakbarian, B.; Casazza, A.A.; Setti, L.; Bernini, C.; Perego, P.; Ferretti, M.

    2013-06-01

    Highlights: ► Photocatalytic deactivation of Escherichia coli in presence of TiO{sub 2} nanoparticles ► The presence of catalyst is less important when the radiation is in the UV range ► Rutile has an higher efficiency respect to anatase under visible light. - Abstract: The photocatalytic deactivation of Escherichia coli HB101 by two different structures of TiO{sub 2}, rutile and anatase (used separately and in a 1:1 mixture), was examined. The microorganism was deposited on a filter membrane containing 520 mg/m{sup 2} of TiO{sub 2} and then irradiated by a neon lamp. In order to study the rate of deactivation of the microorganism we studied four different exposure times: 20, 40, 60 and 90 min. The results showed that rutile has an antimicrobial activity higher than anatase, while the mixture had values near to the average between them in every condition. The highest difference in the inactivation capacity of the two structures is observable at shorter times. The effect of the different crystal phases was evaluated by Scanning Electron Microscopy.

  6. SuperNova, a monomeric photosensitizing fluorescent protein for chromophore-assisted light inactivation.

    PubMed

    Takemoto, Kiwamu; Matsuda, Tomoki; Sakai, Naoki; Fu, Donald; Noda, Masanori; Uchiyama, Susumu; Kotera, Ippei; Arai, Yoshiyuki; Horiuchi, Masataka; Fukui, Kiichi; Ayabe, Tokiyoshi; Inagaki, Fuyuhiko; Suzuki, Hiroshi; Nagai, Takeharu

    2013-01-01

    Chromophore-assisted light inactivation (CALI) is a powerful technique for acute perturbation of biomolecules in a spatio-temporally defined manner in living specimen with reactive oxygen species (ROS). Whereas a chemical photosensitizer including fluorescein must be added to specimens exogenously and cannot be restricted to particular cells or sub-cellular compartments, a genetically-encoded photosensitizer, KillerRed, can be controlled in its expression by tissue specific promoters or subcellular localization tags. Despite of this superiority, KillerRed hasn't yet become a versatile tool because its dimerization tendency prevents fusion with proteins of interest. Here, we report the development of monomeric variant of KillerRed (SuperNova) by direct evolution using random mutagenesis. In contrast to KillerRed, SuperNova in fusion with target proteins shows proper localization. Furthermore, unlike KillerRed, SuperNova expression alone doesn't perturb mitotic cell division. Supernova retains the ability to generate ROS, and hence promote CALI-based functional analysis of target proteins overcoming the major drawbacks of KillerRed.

  7. Synthesis of fluorescent core-shell nanomaterials and strategies to generate white light

    SciTech Connect

    Singh, Amandeep; Kaur, Ramanjot; Pandey, O. P.; Wei, Xueyong; Sharma, Manoj E-mail: manojsharma@bilkent.edu.tr

    2015-07-28

    In this work, cadmium free core-shell ZnS:X/ZnS (X = Mn, Cu) nanoparticles have been synthesized and used for white light generation. First, the doping concentration of Manganese (Mn) was varied from 1% to 4% to optimize the dopant related emission and its optimal value was found to be 1%. Then, ZnS shell was grown over ZnS:Mn(1%) core to passivate the surface defects. Similarly, the optimal concentration of Copper (Cu) was found to be 0.8% in the range varied from 0.6% to 1.2%. In order to obtain an emission in the whole visible spectrum, dual doping of Mn and Cu was done in the core and the shell, respectively. A solid-solid mixing in different ratios of separately doped quantum dots (QDs) emitting in the blue green and the orange region was performed. Results show that the optimum mixture of QDs excited at 300 nm gives Commission Internationale del'Éclairage color coordinates of (0.35, 0.36), high color rendering index of 88, and correlated color temperature of 4704 K with minimum self-absorption.

  8. Synthesis of fluorescent core-shell nanomaterials and strategies to generate white light

    NASA Astrophysics Data System (ADS)

    Singh, Amandeep; Kaur, Ramanjot; Pandey, O. P.; Wei, Xueyong; Sharma, Manoj

    2015-07-01

    In this work, cadmium free core-shell ZnS:X/ZnS (X = Mn, Cu) nanoparticles have been synthesized and used for white light generation. First, the doping concentration of Manganese (Mn) was varied from 1% to 4% to optimize the dopant related emission and its optimal value was found to be 1%. Then, ZnS shell was grown over ZnS:Mn(1%) core to passivate the surface defects. Similarly, the optimal concentration of Copper (Cu) was found to be 0.8% in the range varied from 0.6% to 1.2%. In order to obtain an emission in the whole visible spectrum, dual doping of Mn and Cu was done in the core and the shell, respectively. A solid-solid mixing in different ratios of separately doped quantum dots (QDs) emitting in the blue green and the orange region was performed. Results show that the optimum mixture of QDs excited at 300 nm gives Commission Internationale del'Éclairage color coordinates of (0.35, 0.36), high color rendering index of 88, and correlated color temperature of 4704 K with minimum self-absorption.

  9. The physics of Cerenkov light production during proton therapy.

    PubMed

    Helo, Y; Kacperek, A; Rosenberg, I; Royle, G; Gibson, A P

    2014-12-07

    There is increasing interest in using Cerenkov emissions for quality assurance and in vivo dosimetry in photon and electron therapy. Here, we investigate the production of Cerenkov light during proton therapy and its potential applications in proton therapy. A primary proton beam does not have sufficient energy to generate Cerenkov emissions directly, but we have demonstrated two mechanisms by which such emissions may occur indirectly: (1) a fast component from fast electrons liberated by prompt gamma (99.13%) and neutron (0.87%) emission; and (2) a slow component from the decay of radioactive positron emitters. The fast component is linear with dose and doserate but carries little spatial information; the slow component is non-linear but may be localised. The properties of the two types of emission are explored using Monte Carlo modelling in GEANT4 with some experimental verification. We propose that Cerenkov emissions could contribute to the visual sensation reported by some patients undergoing proton therapy of the eye and we discuss the feasibility of some potential applications of Cerenkov imaging in proton therapy.

  10. Ozone production at the National Synchrotron Light Source

    SciTech Connect

    Weilandics, C.; Rohrig, N.; Gmur, N.F.

    1987-01-01

    Ozone production by synchrotron radiation as a function of power density in air was investigated using a white beam at the BNL National Synchrotron Light Source (NSLS) x-ray ring. Power densities were calculated from the energy spectrum at 2.52 GeV. Ozone concentrations in small beam pipes were measured for power densities between I = 10/sup 12/ and 10/sup 15/ eV . cm/sup -3/ . sec/sup -1/. The measured ozone half-life was 37 +- 2 min. The measured G-value was 2.69 +- 0.14 mol/100 eV and the ozone destruction factor k was less than 7 x 10/sup -19/ cm/sup 3/ . eV/sup -1/. The random uncertainties stated are approximately one standard error. The large departure of the values for G and k from previous values suggest that some undiscovered systematic error may exist in the experiment. Ozone concentration in excess of the 0.1 ppM ACGIH TLV can be generated in the experimental hutches but can readily be controlled. Industrial hygiene aspects of operation and possible control measures will be discussed. 19 refs., 7 figs., 3 tabs.

  11. Assessment of advanced glycated end product accumulation in skin using auto fluorescence multispectral imaging.

    PubMed

    Larsson, Marcus; Favilla, Riccardo; Strömberg, Tomas

    2016-04-12

    Several studies have shown that advanced glycation end products (AGE) play a role in both the microvascular and macrovascular complications of diabetes and are closely linked to inflammation and atherosclerosis. AGEs accumulate in skin and can be detected using their auto fluorescence (AF). A significant correlation exists between AGE AF and the levels of AGEs as obtained from skin biopsies. A commercial device, the AGE Reader, has become available to assess skin AF for clinical purposes but, while displaying promising results, it is limited to single-point measurements performed in contact to skin tissue. Furthermore, in vivo imaging of AGE accumulation is virtually unexplored. We proposed a non-invasive, contact-less novel technique for quantifying fluorescent AGE deposits in skin tissue using a multispectral imaging camera setup (MSI) during ultraviolet (UV) exposure. Imaging involved applying a region-of-interest mask, avoiding specular reflections and a simple calibration. Results of a study conducted on 16 subjects with skin types ranging from fair to deeply pigmented skin, showed that AGE measured with MSI in forearm skin was significantly correlated with the AGE reference method (AGE Reader on forearm skin, R=0.68, p=0.005). AGE measured in facial skin was borderline significantly related to AGE Reader on forearm skin (R=0.47, p=0.078). These results support the use of the technique in devices for non-touch measurement of AGE content in either facial or forearm skin tissue over time.

  12. Integrating Solar Induced Fluorescence and the Photochemical Reflectance Index for Estimating Gross Primary Production in a Cornfield

    NASA Technical Reports Server (NTRS)

    Cheng, Yen-Ben; Middleton, Elizabeth M.; Zhang, Qingyuan; Huemmrich, Karl F.; Campbell, Petya K. E.; Corp, Lawrence A.; Cook, Bruce D.; Kustas, William P.; Daughtry, Criag S.

    2013-01-01

    The utilization of remotely sensed observations for light use efficiency (LUE) and tower-based gross primary production (GPP) estimates was studied in a USDA cornfield. Nadir hyperspectral reflectance measurements were acquired at canopy level during a collaborative field campaign conducted in four growing seasons. The Photochemical Reflectance Index (PRI) and solar induced chlorophyll fluorescence (SIF), were derived. SIF retrievals were accomplished in the two telluric atmospheric oxygen absorption features centered at 688 nm (O2-B) and 760 nm (O2-A). The PRI and SIF were examined in conjunction with GPP and LUE determined by flux tower-based measurements. All of these fluxes, environmental variables, and the PRI and SIF exhibited diurnal as well as day-to-day dynamics across the four growing seasons. Consistent with previous studies, the PRI was shown to be related to LUE (r2 = 0.54 with a logarithm fit), but the relationship varied each year. By combining the PRI and SIF in a linear regression model, stronger performances for GPP estimation were obtained. The strongest relationship (r2 = 0.80, RMSE = 0.186 mg CO2/m2/s) was achieved when using the PRI and SIF retrievals at 688 nm. Cross-validation approaches were utilized to demonstrate the robustness and consistency of the performance. This study highlights a GPP retrieval method based entirely on hyperspectral remote sensing observations.

  13. The Top 10 Products

    ERIC Educational Resources Information Center

    American School & University, 2008

    2008-01-01

    In 2008, American School & University showcased some of the hottest products in the industry. This article presents the 10 most requested, as determined by readers. Products include fluorescent lighting, concrete floor maintenance and exterior sheathing.

  14. Electrophoretic deposition of fluorescent Cu and Au sheets for light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Liu, Jiale; Wu, Zhennan; Li, Tingting; Zhou, Ding; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

    2015-12-01

    Electrophoretic deposition (EPD) is a conventional method for fabricating film materials from nanometer-sized building blocks, and exhibits the advantages of low-cost, high-efficiency, wide-range thickness adjustment, and uniform deposition. Inspired by the interest in the application of two-dimensional (2D) nanomaterials, the EPD technique has been recently extended to building blocks with 2D features. However, the studies are mainly focused on simplex building blocks. The utilization of multiplex building blocks is rarely reported. In this work, we demonstrate a controlled EPD of Cu and Au sheets, which are 2D assemblies of luminescent Cu and Au nanoclusters. Systematic investigations reveal that both the deposition efficiency and the thickness are determined by the lateral size of the sheets. For Cu sheets with a large lateral size, a high ζ-potential and strong face-to-face van der Waals interactions facilitate the deposition with high efficiency. However, for Au sheets, the small lateral size and ζ-potential limit the formation of a thick film. To solve this problem, the deposition dynamics are controlled by increasing the concentration of the Au sheets and adding acetone. This understanding permits the fabrication of a binary EPD film by the stepwise deposition of Cu and Au sheets, thus producing a luminescent film with both Cu green emission and Au red emission. A white light-emitting diode prototype with color coordinates (x, y) = (0.31, 0.36) is fabricated by employing the EPD film as a color conversion layer on a 365 nm GaN clip and further tuning the amount of deposited Cu and Au sheets.Electrophoretic deposition (EPD) is a conventional method for fabricating film materials from nanometer-sized building blocks, and exhibits the advantages of low-cost, high-efficiency, wide-range thickness adjustment, and uniform deposition. Inspired by the interest in the application of two-dimensional (2D) nanomaterials, the EPD technique has been recently extended to

  15. A Fluorescence Approach to Assess the Production of Soluble Microbial Products from Aerobic Granular Sludge Under the Stress of 2,4-Dichlorophenol.

    PubMed

    Wei, Dong; Dong, Heng; Wu, Na; Ngo, Huu Hao; Guo, Wenshan; Du, Bin; Wei, Qin

    2016-04-14

    In this study, a fluorescence approach was used to evaluate the production of soluble microbial products (SMP) in aerobic granular sludge system under the stress of 2,4-dichlorophenol (2,4-DCP). A combined use of three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM), Parallel factor analysis (PARAFAC), synchronous fluorescence and two-dimensional correlation spectroscopy (2D-COS) were explored to respect the SMP formation in the exposure of different doses of 2,4-DCP. Data implied that the presence of 2,4-DCP had an obvious inhibition on biological nitrogen removal. According to EEM-PARAFAC, two fluorescent components were derived and represented to the presence of fulvic-like substances and humic-like substances in Component 1 and protein-like substances in Component 2. It was found from synchronous fluorescence that protein-like peak presented slightly higher intensity than that of fulvic-like peak. 2D-COS further revealed that fluorescence change took place sequentially in the following order: protein-like fraction > fulvic-like fraction. The obtained results could provide a potential application of fluorescence spectra in the released SMP assessment in the exposure of toxic compound during wastewater treatment.

  16. A Fluorescence Approach to Assess the Production of Soluble Microbial Products from Aerobic Granular Sludge Under the Stress of 2,4-Dichlorophenol

    PubMed Central

    Wei, Dong; Dong, Heng; Wu, Na; Ngo, Huu Hao; Guo, Wenshan; Du, Bin; Wei, Qin

    2016-01-01

    In this study, a fluorescence approach was used to evaluate the production of soluble microbial products (SMP) in aerobic granular sludge system under the stress of 2,4-dichlorophenol (2,4-DCP). A combined use of three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM), Parallel factor analysis (PARAFAC), synchronous fluorescence and two-dimensional correlation spectroscopy (2D-COS) were explored to respect the SMP formation in the exposure of different doses of 2,4-DCP. Data implied that the presence of 2,4-DCP had an obvious inhibition on biological nitrogen removal. According to EEM-PARAFAC, two fluorescent components were derived and represented to the presence of fulvic-like substances and humic-like substances in Component 1 and protein-like substances in Component 2. It was found from synchronous fluorescence that protein-like peak presented slightly higher intensity than that of fulvic-like peak. 2D-COS further revealed that fluorescence change took place sequentially in the following order: protein-like fraction > fulvic-like fraction. The obtained results could provide a potential application of fluorescence spectra in the released SMP assessment in the exposure of toxic compound during wastewater treatment. PMID:27075778

  17. CH3 NH3 PbBr3 Perovskite Nanocrystals as Efficient Light-Harvesting Antenna for Fluorescence Resonance Energy Transfer.

    PubMed

    Muthu, Chinnadurai; Vijayan, Anuja; Nair, Vijayakumar C

    2017-03-16

    Hybrid perovskites have created enormous research interest as a low-cost material for high-performance photovoltaic devices, light-emitting diodes, photodetectors, memory devices and sensors. Perovskite materials in nanocrystal form that display intense luminescence due to the quantum confinement effect were found to be particularly suitable for most of these applications. However, the potential use of perovskite nanocrystals as a light-harvesting antenna for possible applications in artificial photosynthesis systems is not yet explored. In the present work, we study the light-harvesting antenna properties of luminescent methylammonium lead bromide (CH3 NH3 PbBr3 )-based perovskite nanocrystals using fluorescent dyes (rhodamine B, rhodamine 101, and nile red) as energy acceptors. Our studies revealed that CH3 NH3 PbBr3 nanocrystals are an excellent light-harvesting antenna, and efficient fluorescence resonance energy transfer occurs from the nanocrystals to fluorescent dyes. Further, the energy transfer efficiency is found to be highly dependent on the number of anchoring groups and binding ability of the dyes to the surface of the nanocrystals. These observations may have significant implications for perovskite-based light-harvesting devices and their possible use in artificial photosynthesis systems.

  18. 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.

  19. Production of Superoxide in Bacteria Is Stress- and Cell State-Dependent: A Gating-Optimized Flow Cytometry Method that Minimizes ROS Measurement Artifacts with Fluorescent Dyes.

    PubMed

    McBee, Megan E; Chionh, Yok H; Sharaf, Mariam L; Ho, Peiying; Cai, Maggie W L; Dedon, Peter C

    2017-01-01

    The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions. False positives and variability among sample types (e.g., bacterial species, stress conditions) are reduced with a flexible four-step gating scheme that accounts for side- and forward-scattered light (morphological changes), background fluorescence, DNA content, and dye uptake to identify cells producing ROS. Using CellROX Green dye with Escherichia coli, Mycobacterium smegmatis, and Mycobacterium bovis BCG as diverse model bacteria, we show that (1) the generation of a quantifiable CellROX Green signal for superoxide, but not hydrogen peroxide-induced hydroxyl radicals, validates this dye as a superoxide detector; (2) the level of dye-detectable superoxide does not correlate with cytotoxicity or antibiotic sensitivity; (3) the non-replicating, antibiotic tolerant state of nutrient-deprived mycobacteria is associated with high levels of superoxide; and (4) antibiotic-induced production of superoxide is idiosyncratic with regard to both the species and the physiological state of the bacteria. We also show that the gating method is applicable to other fluorescent indicator dyes, such as the 5-carboxyfluorescein diacetate acetoxymethyl ester and 5-cyano-2,3-ditolyl tetrazolium chloride for cellular esterase and reductive respiratory activities, respectively. These results demonstrate that properly controlled flow cytometry coupled

  20. Production of Superoxide in Bacteria Is Stress- and Cell State-Dependent: A Gating-Optimized Flow Cytometry Method that Minimizes ROS Measurement Artifacts with Fluorescent Dyes

    PubMed Central

    McBee, Megan E.; Chionh, Yok H.; Sharaf, Mariam L.; Ho, Peiying; Cai, Maggie W. L.; Dedon, Peter C.

    2017-01-01

    The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions. False positives and variability among sample types (e.g., bacterial species, stress conditions) are reduced with a flexible four-step gating scheme that accounts for side- and forward-scattered light (morphological changes), background fluorescence, DNA content, and dye uptake to identify cells producing ROS. Using CellROX Green dye with Escherichia coli, Mycobacterium smegmatis, and Mycobacterium bovis BCG as diverse model bacteria, we show that (1) the generation of a quantifiable CellROX Green signal for superoxide, but not hydrogen peroxide-induced hydroxyl radicals, validates this dye as a superoxide detector; (2) the level of dye-detectable superoxide does not correlate with cytotoxicity or antibiotic sensitivity; (3) the non-replicating, antibiotic tolerant state of nutrient-deprived mycobacteria is associated with high levels of superoxide; and (4) antibiotic-induced production of superoxide is idiosyncratic with regard to both the species and the physiological state of the bacteria. We also show that the gating method is applicable to other fluorescent indicator dyes, such as the 5-carboxyfluorescein diacetate acetoxymethyl ester and 5-cyano-2,3-ditolyl tetrazolium chloride for cellular esterase and reductive respiratory activities, respectively. These results demonstrate that properly controlled flow cytometry coupled

  1. Dynamics of triacylglycerol and EPA production in Phaeodactylum tricornutum under nitrogen starvation at different light intensities.

    PubMed

    Remmers, Ilse M; Martens, Dirk E; Wijffels, René H; Lamers, Packo P

    2017-01-01

    Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 μmol m-2 s-1). The highest TAG yield on light (112 mg TAG molph-1) was found at the lowest light intensity tested (60 μmol m-2 s-1), which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.

  2. Spectral conversion of light for enhanced microalgae growth rates and photosynthetic pigment production.

    PubMed

    Mohsenpour, Seyedeh Fatemeh; Richards, Bryce; Willoughby, Nik

    2012-12-01

    The effect of light conditions on the growth of green algae Chlorella vulgaris and cyanobacteria Gloeothece membranacea was investigated by filtering different wavelengths of visible light and comparing against a model daylight source as a control. Luminescent acrylic sheets containing violet, green, orange or red dyes illuminated by a solar simulator produced the desired wavelengths of light for this study. From the experimental results the highest specific growth rate for C. vulgaris was achieved using the orange range whereas violet light promoted the growth of G. membranacea. Red light exhibited the least efficiency in conversion of light energy into biomass in both strains of microalgae. Photosynthetic pigment formation was examined and maximum chlorophyll-a production in C. vulgaris was obtained by red light illumination. Green light yielded the best chlorophyll-a production in G. membranacea. The proposed illumination strategy offers improved microalgae growth without resorting to artificial light sources, reducing energy use and costs of cultivation.

  3. Advantages of diffuse light for horticultural production and perspectives for further research

    PubMed Central

    Li, Tao; Yang, Qichang

    2015-01-01

    Plants use diffuse light more efficiently than direct light, which is well established due to diffuse light penetrates deeper into the canopy and photosynthetic rate of a single leaf shows a non-linear response to the light flux density. Diffuse light also results in a more even horizontal and temporal light distribution in the canopy, which plays substantial role for crop photosynthesis enhancement as well as production improvement. Here we show some of the recent findings about the effect of diffuse light on light distribution over the canopy and its direct and indirect effects on crop photosynthesis and plant growth, and suggest some perspectives for further research which could strengthen the scientific understanding of diffuse light modulate plant processes and its application in horticultural production. PMID:26388890

  4. Light Sources and Lighting Circuits

    NASA Astrophysics Data System (ADS)

    Honda, Hisashi; Suwa, Takumi; Yasuda, Takeo; Ohtani, Yoshihiko; Maehara, Akiyoshi; Okada, Atsunori; Komatsu, Naoki; Mannami, Tomoaki

    According to the Machinery Statistics of the Ministry of Economy, Trade and Industry, the production of incandescent lamps in Japan in 2007 was 990 million units (90.0% of the previous year's total), in which the production of incandescent lamps for general lighting was 110 million units (90.0% of the previous year's total) and of tungsten-halogen lamps was 44 million units (96.6% of the previous year's total). The production of fluorescent lamps was 927 million units (93.9% of the previous year's total), in which general fluorescent lamps, excluding those for LCD back lighting, was 320 million units (87.2% of the previous year's total). Also, the production of HID lamps was 10 million units (101.5% of the previous year's total). On the other hand, when the numbers of sales are compared with the sales of the previous year, incandescent lamps for general use was 99.8%, tungsten-halogen lamps was 96.9%, fluorescent lamps was 95.9%, and HID lamps was 98.9%. Self-ballasted fluorescent lamps alone showed an increase in sales as strong as 29 million units, or 121.7% of the previous year's sales. It is considered that the switchover of incandescent lamps to HID lamps was promoted for energy conservation and carbon dioxide reduction with the problem of global warming in the background. In regard to exhibitions, Lighting Fair 2007 was held in Tokyo in March, and LIGHTFAIR INTERNATIONAL 2007 was held in New York in May. Regarding academic conferences, LS:11 (the 11th International Symposium on the Science & Technology of Light Sources) was held in Shanghai in May, and the First International Conference on White LEDs and Solid State Lighting was held in Tokyo in November. Both conferences suggested that there are strong needs and concerns now about energy conservation, saving natural resources, and restrictions of hazardous materials. In regard to incandescent lamps, the development of products aiming at higher efficacy, electric power savings, and longer life was advanced by

  5. Production and Reutilization of Fluorescent Dissolved Organic Matter by a Marine Bacterial Strain, Alteromonas macleodii

    PubMed Central

    Goto, Shuji; Tada, Yuya; Suzuki, Koji; Yamashita, Youhei

    2017-01-01

    The recalcitrant fraction of marine dissolved organic matter (DOM) plays an important role in carbon storage on the earth’s surface. Bacterial production of recalcitrant DOM (RDOM) has been proposed as a carbon sequestration process. It is still unclear whether bacterial physiology can affect RDOM production. In this study, we conducted a batch culture using the marine bacterial isolate Alteromonas macleodii, a ubiquitous gammaproteobacterium, to evaluate the linkage between bacterial growth and DOM production. Glucose (1 mmol C L-1) was used as the sole carbon source, and the bacterial number, the DOM concentration in terms of carbon, and the excitation–emission matrices (EEMs) of DOM were monitored during the 168-h incubation. The incubation period was partitioned into the exponential growth (0–24 h) and stationary phases (24–168 h) based on the growth curve. Although the DOM concentration decreased during the exponential growth phase due to glucose consumption, it remained stable during the stationary phase, corresponding to approximately 4% of the initial glucose in terms of carbon. Distinct fluorophores were not evident in the EEMs at the beginning of the incubation, but DOM produced by the strain exhibited five fluorescent peaks during exponential growth. Two fluorescent peaks were similar to protein-like fluorophores, while the others could be categorized as humic-like fluorophores. All fluorophores increased during the exponential growth phase. The tryptophan-like fluorophore decreased during the stationary phase, suggesting that the strain reused the large exopolymer. The tyrosine-like fluorophore seemed to be stable during the stationary phase, implying that the production of tyrosine-containing small peptides through the degradation of exopolymers was correlated with the reutilization of the tyrosine-like fluorophore. Two humic-like fluorophores that showed emission maxima at the longer wavelength (525 nm) increased during the stationary phase

  6. Colour and surface fluorescence development and their relationship with Maillard reaction markers as influenced by structural changes during cornflakes production.

    PubMed

    Farroni, Abel; Buera, María Del Pilar

    2012-12-01

    The aim of this work was to study colour and surface fluorescence development in relation to the chemical markers for the Maillard reaction at the cooking, flaking and toasting stages of cornflake production process. Colour was measured by a calibrated computer vision system. Surface fluorescence was measured on compressed samples. Aqueous extracted Maillard reaction markers (hydroxymethylfurfural, carboxymethyl-lysine, absorbance at 420nm and total fluorescence) were measured on protease hydrolyzed samples. Sample microstructure was observed by scanning electron microscopy. During cooking the colour coordinates L(∗) and b(∗) decreased and a(∗) increased. After flaking, the samples appeared lighter, while the pigment concentration, fluorescence and hydroxymethylfurfural did not change. Toasting generated bubbles in the matrix and L(∗) apparently increased, although brown pigment concentration increased. Pigment concentration did not correlate with surface colour due to the destruction or generation of interfaces. Surface and microstructure effects can be avoided by milling and compressing the samples.

  7. Hypertriton and light nuclei production at Lambda-production subthreshold energy in heavy-ion collisions

    SciTech Connect

    Zhang, S.; Zu, Z.; Chen, J.H., Ma, Y.G., Cai, X-Z, Ma, G.L., Zhong, C.

    2011-08-01

    High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion ({sup 3}He), and hypertriton ({sub {Lambda}}{sup 3}H) at subthreshold energy of Aproduction ({approx} 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S{sub 3} = {sup 3}{sub {Lambda}}H/({sup 3}He x {Lambda}/p)) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few {mu}b in {sup 36}Ar+{sup 36}Ar, {sup 40}Ca+{sup 40}Ca and {sup 56}Ni+{sup 56}Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at {Lambda} subthreshold energy are suitable for breaking new ground in hypernuclear physics.

  8. Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime.

    PubMed

    van Oort, Bart; Maréchal, Amandine; Ruban, Alexander V; Robert, Bruno; Pascal, Andrew A; de Ruijter, Norbert C A; van Grondelle, Rienk; van Amerongen, Herbert

    2011-07-21

    In 2005, it was found that the fluorescence of crystals of the major light-harvesting complex LHCII of green plants is significantly quenched when compared to the fluorescence of isolated LHCII (A. A. Pascal et al., Nature, 2005, 436, 134-137). The Raman spectrum of crystallized LHCII was also found to be different from that of isolated LHCII but very similar to that of aggregated LHCII, which has often been considered a good model system for studying nonphotochemical quenching (NPQ), the major protection mechanism of plants against photodamage in high light. It was proposed that in the crystal LHCII adopts a similar (quenching) conformation as during NPQ and indeed similar changes in the Raman spectrum were observed during NPQ in vivo (A. V. Ruban et al., Nature, 2007, 450, 575-579). We now compared the fluorescence of various types of crystals, differing in morphology and age. Each type gave rise to its own characteristic mono-exponential fluorescence lifetime, which was 5 to 10 times shorter than that of isolated LHCII. This indicates that fluorescence is not quenched by random impurities and packing defects (as proposed recently by T. Barros et al., EMBO Journal, 2009, 28, 298-306), but that LHCII adopts a particular structure in each crystal type, that leads to fluorescence quenching. Most interestingly, the extent of quenching appears to depend on the crystal morphology, indicating that also the crystal structure depends on this crystal morphology but at the moment no data are available to correlate the crystals' structural changes to changes in fluorescence lifetime.

  9. Correlated light and electron microscopy observations of the uterine epithelial cell actin cytoskeleton using fluorescently labeled resin-embedded sections.

    PubMed

    Moore, Chad L; Cheng, Delfine; Shami, Gerald J; Murphy, Christopher R

    2016-05-01

    In order to perform correlative light and electron microscopy (CLEM) more precisely, we have modified existing specimen preparation protocols allowing fluorescence retention within embedded and sectioned tissue, facilitating direct observation across length scales. We detail a protocol which provides a precise correlation accuracy using accessible techniques in biological specimen preparation. By combining a pre-embedding uranyl acetate staining step with the progressive lowering of temperature (PLT) technique, a methacrylate embedded tissue specimen is ultrathin sectioned and mounted onto a TEM finder grid for immediate viewing in the confocal and electron microscope. In this study, the protocol is applied to rat uterine epithelial cells in vivo during early pregnancy. Correlative overlay data was used to track changes in filamentous actin that occurs in these cells from fertilization (Day 1) to implantation on Day 6 as part of the plasma membrane transformation, a process essential in the development of uterine receptivity in the rat. CLEM confirmed that the actin cytoskeleton is disrupted as apical microvilli are progressively lost toward implantation, and revealed the thick and continuous terminal web is replaced by a thinner and irregular actin band, with individually distinguishable filaments connecting actin meshworks which correspond with remaining plasma membrane protrusions.

  10. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function

    NASA Astrophysics Data System (ADS)

    Fei, Peng; Lee, Juhyun; Packard, René R. Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C.-C. Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K.

    2016-03-01

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases.

  11. Acoustic waves from mechanical impulses due to fluorescence resonant energy (Förster) transfer: Blowing a whistle with light

    NASA Astrophysics Data System (ADS)

    Zurita-Sánchez, J. R.; Henkel, C.

    2012-02-01

    We present a momentum transfer mechanism mediated by electromagnetic fields that originates in a system of two nearby molecules: one excited (donor D*) and the other in ground state (acceptor A). An intermolecular force related to fluorescence resonant energy or Förster transfer (FRET) arises in the unstable D*A molecular system, which differs from the equilibrium van der Waals interaction. Due to the its finite lifetime, a mechanical impulse is imparted to the relative motion in the system. We analyze the FRET impulse when the molecules are embedded in free space and find that its magnitude can be much greater than the single recoil photon momentum, getting comparable with the thermal momentum (Maxwell-Boltzmann distribution) at room temperature. In addition, we propose that this FRET impulse can be exploited in the generation of acoustic waves inside a film containing layers of donor and acceptor molecules, when a picosecond laser pulse excites the donors. This acoustic transient is distinguishable from that produced by thermal stress due to laser absorption, and may therefore play a role in photoacoustic spectroscopy. The effect can be seen as exciting a vibrating system like a string or organ pipe with light; it may be used as an opto-mechanical transducer.

  12. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function.

    PubMed

    Fei, Peng; Lee, Juhyun; Packard, René R Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C-C Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K

    2016-03-03

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases.

  13. Non-rigid contour-to-pixel registration of photographic and quantitative light-induced fluorescence imaging of decalcified teeth

    NASA Astrophysics Data System (ADS)

    Berkels, Benjamin; Deserno, Thomas; Ehrlich, Eva E.; Fritz, Ulrike B.; Sirazitdinova, Ekaterina; Tatano, Rosalia

    2016-03-01

    Quantitative light-induced fluorescence (QLF) is widely used to assess the damage of a tooth due to decalcification. In digital photographs, decalcification appears as white spot lesions, i.e. white spots on the tooth surface. We propose a novel multimodal registration approach for the matching of digital photographs and QLF images of decalcified teeth. The registration is based on the idea of contour-to-pixel matching. Here, the curve, which represents the shape of the tooth, is extracted from the QLF image using a contour segmentation by binarization and morphological processing. This curve is aligned to the photo with a non-rigid variational registration approach. Thus, the registration problem is formulated as minimization problem with an objective function that consists of a data term and a regularizer for the deformation. To construct the data term, the photo is pointwise classified into tooth and non-tooth regions. Then, the signed distance function of the tooth region allows to measure the mismatch between curve and photo. As regularizer a higher order, linear elastic prior is used. The resulting minimization problem is solved numerically using bilinear Finite Elements for the spatial discretization and the Gauss-Newton algorithm. The evaluation is based on 150 image pairs, where an average of 5 teeth have been captured from 32 subjects. All registrations have been confirmed correctly by a dental expert. The contour-to-pixel methods can directly be used in 3D for surface-to-voxel tasks.

  14. The role of cerebral spinal fluid in light propagation through the mouse head: improving fluorescence tomography with Monte Carlo modeling

    NASA Astrophysics Data System (ADS)

    Ancora, Daniele; Zacharopoulos, Athanasios; Ripoll, Jorge; Zacharakis, Giannis

    2016-03-01

    Optical Neuroimaging is a highly dynamical field of research owing to the combination of many advanced imaging techniques and computational tools that uncovered unexplored paths through the functioning of the brain. Light propagation modelling through such complicated structures has always played a crucial role as the basis for a high resolution and quantitative imaging where even the slightest improvement could lead to significant results. Fluorescence Diffuse Optical Tomography (fDOT), a widely used technique for three dimensional imaging of small animals and tissues, has been proved to be inaccurate for neuroimaging the mouse head without the knowledge of a-priori anatomical information of the subject. Commonly a normalized Born approximation model is used in fDOT reconstruction based on forward photon propagation using Diffusive Equation (DE) which has strong limitations in the optically clear regime. The presence of the Cerebral Spinal Fluid (CSF) instead, a thin optically clear layer surrounding the brain, can be more accurately taken into account using Monte Carlo approaches which nowadays is becoming more usable thanks to parallelized GPU algorithms. In this work we discuss the results of a synthetic experimental comparison, resulting to the increase of the accuracy for the Born approximation by introducing the CSF layer in a realistic mouse head structure with respect to the current model. We point out the importance of such clear layer for complex geometrical models, while for simple slab phantoms neglecting it does not introduce a significant error.

  15. Cardiac Light-Sheet Fluorescent Microscopy for Multi-Scale and Rapid Imaging of Architecture and Function

    PubMed Central

    Fei, Peng; Lee, Juhyun; Packard, René R. Sevag; Sereti, Konstantina-Ioanna; Xu, Hao; Ma, Jianguo; Ding, Yichen; Kang, Hanul; Chen, Harrison; Sung, Kevin; Kulkarni, Rajan; Ardehali, Reza; Kuo, C.-C. Jay; Xu, Xiaolei; Ho, Chih-Ming; Hsiai, Tzung K.

    2016-01-01

    Light Sheet Fluorescence Microscopy (LSFM) enables multi-dimensional and multi-scale imaging via illuminating specimens with a separate thin sheet of laser. It allows rapid plane illumination for reduced photo-damage and superior axial resolution and contrast. We hereby demonstrate cardiac LSFM (c-LSFM) imaging to assess the functional architecture of zebrafish embryos with a retrospective cardiac synchronization algorithm for four-dimensional reconstruction (3-D space + time). By combining our approach with tissue clearing techniques, we reveal the entire cardiac structures and hypertrabeculation of adult zebrafish hearts in response to doxorubicin treatment. By integrating the resolution enhancement technique with c-LSFM to increase the resolving power under a large field-of-view, we demonstrate the use of low power objective to resolve the entire architecture of large-scale neonatal mouse hearts, revealing the helical orientation of individual myocardial fibers. Therefore, our c-LSFM imaging approach provides multi-scale visualization of architecture and function to drive cardiovascular research with translational implication in congenital heart diseases. PMID:26935567

  16. High Power Efficiency Blue-to-Green Organic Light-Emitting Diodes Using Isonicotinonitrile-Based Fluorescent Emitters.

    PubMed

    Sasabe, Hisahiro; Onuma, Natsuki; Nagai, Yuji; Ito, Takashi; Kido, Junji

    2017-03-16

    Herein, 9,10-dihydro-9,9-dimethylacridine (Ac) or phenoxazine (PXZ)-substituted isonicotinonitrile (INN) derivatives, denoted as 2AcINN, 26AcINN, and 26PXZINN, were developed as a series of thermally activated delayed fluorescence (TADF) emitters. These emitters showed reasonably high photoluminescence quantum yields of 71-79 % in the host films and high power efficiency organic light-emitting diodes (OLEDs). Sky-blue emitter 26AcINN exhibited a low turn-on voltage of 2.9 V, a high external quantum efficiency (ηext ) of 22 %, and a high power efficiency (ηp ) of 66 lm W(-1) with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.22, 0.45), whereas green emitter 26PXZINN exhibited a low turn-on voltage of 2.2 V, a high ηext of 22 %, and a high ηp of 99 lm W(-1) with CIE chromaticity coordinates of (0.37, 0.58). These performances are among the best for TADF OLEDs to date.

  17. Improving the monitoring of crop productivity using spaceborne solar-induced fluorescence.

    PubMed

    Guan, Kaiyu; Berry, Joseph A; Zhang, Yongguang; Joiner, Joanna; Guanter, Luis; Badgley, Grayson; Lobell, David B

    2016-02-01

    Large-scale monitoring of crop growth and yield has important value for forecasting food production and prices and ensuring regional food security. A newly emerging satellite retrieval, solar-induced fluorescence (SIF) of chlorophyll, provides for the first time a direct measurement related to plant photosynthetic activity (i.e. electron transport rate). Here, we provide a framework to link SIF retrievals and crop yield, accounting for stoichiometry, photosynthetic pathways, and respiration losses. We apply this framework to estimate United States crop productivity for 2007-2012, where we use the spaceborne SIF retrievals from the Global Ozone Monitoring Experiment-2 satellite, benchmarked with county-level crop yield statistics, and compare it with various traditional crop monitoring approaches. We find that a SIF-based approach accounting for photosynthetic pathways (i.e. C3 and C4 crops) provides the best measure of crop productivity among these approaches, despite the fact that SIF sensors are not yet optimized for terrestrial applications. We further show that SIF provides the ability to infer the impacts of environmental stresses on autotrophic respiration and carbon-use-efficiency, with a substantial sensitivity of both to high temperatures. These results indicate new opportunities for improved mechanistic understanding of crop yield responses to climate variability and change.

  18. A fluorescent light-up aggregation-induced emission probe for screening gefitinib-sensitive non-small cell lung carcinoma.

    PubMed

    Hu, Yi; Shi, Leilei; Su, Yue; Zhang, Chuan; Jin, Xin; Zhu, Xinyuan

    2017-03-07

    Fluorescent light-up probes with aggregation-induced emission (AIE) characteristics have been focused on recently. In this report, a new fluorescent probe, namely, DEVD-TPE, which consisted of the substrate peptide Asp-Glu-Val-Asp (DEVD) and the AIE reporter group tetraphenylethene (TPE), was developed for detecting caspase-3 in living cells. In a slightly alkaline solution, the DEVD-TPE probe displayed almost no fluorescence owing to the dynamic rotation of the phenyl rings in solution. However, DEVD-TPE exhibited significant fluorescence when it was cleaved by caspase-3, as well as when the reporter group TPE underwent aggregation. The epidermal growth factor receptor (EGFR) inhibitor gefitinib was used for determining the screening efficacy of the probe for different non-small cell lung carcinoma (NSCLC) cell lines, namely, HCC827, A549 and H1650 cells. Cell proliferation and apoptosis assays indicated that the three cell lines had different sensitivities to gefitinib. The results of analysis by living-cell fluorescence imaging and flow cytometry were consistent with those of the cell proliferation and apoptosis assays. This demonstrated that our probe could detect caspase-3 in living cells, which confirmed the apoptosis of NSCLC cells. Furthermore, our probe indicated that gefitinib was more efficient against HCC827 cells than against the other two NSCLC cell lines. This report proves that the fluorescent probe DEVD-TPE is highly sensitive to caspase-3 and has potential prospects in the rapid screening of NSCLC.

  19. Analysis of the effects of blue light on morphofunctional status of in vitro cultured blastocysts from mice carrying gene of enhanced green fluorescent protein (EGFP).

    PubMed

    Sakharova, N Yu; Mezhevikina, L M; Smirnov, A A; Vikhlyantseva, E F

    2014-05-01

    We studied the effect of blue light (440-490 nm) on the development of late blastocysts of mice carrying the gene of enhanced green fluorescent protein (EGFP). Exposure to blue light for 20 min reduced adhesive properties of blastocysts and their capacity to form primary colonies consisting of the cells of inner cell mass, trophoblast, and extraembryonic endoderm. The negative effects of blue light manifested in morphological changes in the primary colonies and impairment of differentiation and migration of cells of the trophoblast and extraembryonic endoderm. The problems of cell-cell interaction and inductive influences of the inner cell mass on other cell subpopulations are discussed. EGFP blastocysts were proposed as the model for evaluation of the mechanisms underlying the effects of blue light as the major negative factor of visible light used in in vitro experiments on mammalian embryos.

  20. Impact of light quality on biomass production and fatty acid content in the microalga Chlorella vulgaris.

    PubMed

    Hultberg, Malin; Jönsson, Helene Larsson; Bergstrand, Karl-Johan; Carlsson, Anders S

    2014-05-01

    In this study, the green microalga Chlorella vulgaris was exposed to monochromatic light at six different wavelengths in order to study the effect on biomass productivity and fatty acid content. A significantly higher amount of biomass by produced in the treatments with yellow, red and white light compared with blue, green and purple light. There were also significant differences in total lipid content and fatty acid profile between the treatments. The green light regime gave the lowest concentration of lipids, but increased the concentration of polyunsaturated fatty acids. Thus it can be concluded that light quality significantly affects biomass productivity, total lipid concentration and fatty acid profile in the microalga C. vulgaris.

  1. Analysis of Light Gathering Abilities of Dynamically Solidified Micro-lenses, and Their Implementation to Improve Sensitivity of Fluorescent PCR Micro-detectors.

    PubMed

    Wu, Jian; Guo, Wei; Wang, Chunyan; Yu, Kuanxin; Chen, Tao; Li, Yinghui

    2015-06-01

    Fluorescent polymerase chain reaction (PCR) is becoming the preferred method of quantitative analysis due to its high specificity and sensitivity. We propose to use a new kind of micro-lens, dynamically solidified with optic glue, to improve the sensitivity of fluorescent PCR micro-detector. We developed light ray track equations for these lenses and used them to calculate relative light intensity distribution curve for stimulation lenses and illumination point probability distribution curve for detection lenses. We manufactured dynamically solidified micro-lenses using optic glue NOA61, and measured their light gathering ability. Lenses with radius/thickness (R/H) ratio of 4 reached light focusing ratio of 3.85 (stimulation lens) and photon collection efficiency of 0.86 (detection lens). We then used dynamically solidified lenses in PCR fluorescence micro-detector and analyzed their effect on the detector sensitivity. We showed that the use of dynamically solidified micro-lenses with R/H = 4 resulted in over 4.4-fold increased sensitivity of the detector.

  2. Fluorescent redox dyes. 1. Production of fluorescent formazan by unstimulated and phorbol ester- or digitonin-stimulated Ehrlich ascites tumor cells.

    PubMed

    Stellmach, J

    1984-01-01

    The reduction of a new series of tetrazolium salts to red fluorescent formazans by Ehrlich ascites tumor cells is described. The qualitative effect on this reaction of two cell surface-active compounds and of six exogenous electron carriers was investigated by varying the incubation conditions. After incubation of Ehrlich ascites cells with the new colourless, water soluble 5-cyan-2.3-ditolyltetrazolium salts, bright red water-insoluble formazan crystals on the cell surface can be observed under fluorescence microscopy. The production of formazan is enhanced by 12-0-tetradecanoyl-phorbol-13-acetate (TPA) or digitonin (DIG), two potent stimulators of oxygen consumption or by the electron carriers phenazine methosulphate (PMS), 1-methoxy-phenazine methosulphate (MPMS), meldola blue (MB), methylene blue (MTB), and 2.6-dichlorindophenol (DCIP). These results provide further evidence for the existence of redox enzymes bound to the plasma membrane of intact ascites cells and for a free radical mechanism of tetrazolium salt reduction. The fluorescence property of the new redox dyes offers the advantage of high sensitivity. Moreover, their greater homogeneity relative to the commonly used di-tetrazolium salts lowers the chances of misinterpretations due to impurities. The possible application of these new mono-tetrazolium salts to cytochemical investigations of oxidative metabolic reactions is discussed.

  3. Enhancement of microalgae production by embedding hollow light guides to a flat-plate photobioreactor.

    PubMed

    Sun, Yahui; Huang, Yun; Liao, Qiang; Fu, Qian; Zhu, Xun

    2016-05-01

    To offset the adverse effects of light attenuation on microalgae growth, hollow polymethyl methacrylate (PMMA) tubes were embedded into a flat-plate photobioreactor (PBR) as light guides. In this way, a fraction of incident light could be transmitted and emitted to the interior of the PBR, providing a secondary light source for cells in light-deficient regions. The average light intensity of interior regions 3-6cm from surfaces with 70μmolm(-2)s(-1) incident light was enhanced 2-6.5 times after 3.5days cultivation, resulting in a 23.42% increase in biomass production to that cultivated in PBR without PMMA tubes. The photosynthetic efficiency of microalgae in the proposed PBR was increased to 12.52%. Moreover, the installation of hollow PMMA tubes induced turbulent flow in the microalgae suspension, promoting microalgae suspension mixing. However, the enhanced biomass production was mainly attributed to the optimized light distribution in the PBR.

  4. Stimulatory effects of blue light on the growth, monascin and ankaflavin production in Monascus.

    PubMed

    Wang, Changlu; Chen, Di; Chen, Mianhua; Wang, Yurong; Li, Zhenjing; Li, Fengjuan

    2015-05-01

    Light is an important signal for fungi. We analyzed the influence of blue light of various intensities and illumination times on growth, monascin (MS) and ankaflavin (AK) biosyntheses in Monascus strain M9. Blue light changed the color of colonies. The colonies grown in the dark were orange, but turned pale when exposed to continuous blue light. MS production increased by 12.5, 27, and 14.5 % under blue light of 100 lux for 15 min/day, 100 lux for 30 min/day, and 200 lux for 15 min/day, respectively, compared to growth in the dark. AK production increased by 14.4, 22, and 13 % under the same condition. MS and AK production decreased when exposed to blue light of 300 and 450 lux. The expression of pigment biosynthetic genes were analyzed by real-time quantitative PCR and correlated with phenotypic production of MS and AK.

  5. Effects of fluid and light dynamics on H2 production in a mechanically stirred photobioreactor.

    PubMed

    Zhang, T

    2013-10-01

    Hydrogen productions through biophotolysis by microalgae in photobioreactors (PBRs) were studied using a computational model integrated with fluid dynamics, particle tracking technique, light attenuation dynamics, biochemical kinetics, and mass transport. The trajectories of microalgae entrained in the flow fields within these PBRs were traced by the particle tracking technique and were used to determine the dynamics of light attenuation subjected by the cells, which were analyzed and compared with those obtained from the unstirred PBR under different incident light illuminations. The results show an improvement on the light penetration depth in the mechanically stirred cultures. The dynamics of light attenuation was incorporated into the kinetics equations for the analysis of the inhomogeneous biochemical process for hydrogen production by microalgae. Hydrogen production in the unstirred and the impeller-stirred PBRs were determined under different light illumination conditions and the results show an improvement on hydrogen production in the impeller-stirred PBRs.

  6. 77 FR 55499 - Certain Light-Emitting Diodes and Products Containing Same; Commission Determination Not To...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-10

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Light-Emitting Diodes and Products Containing Same; Commission Determination Not To Review... States after importation of certain light-emitting diodes and products containing same by reason...

  7. Tuning the production of variable length, fluorescent polyisoprenoids using surfactant-controlled enzymatic synthesis.

    PubMed

    Troutman, Jerry M; Erickson, Katelyn M; Scott, Phillip M; Hazel, Joseph M; Martinez, Christina D; Dodbele, Samantha

    2015-05-12

    Bactoprenyl diphosphate (BPP), a two-E eight-Z configuration C55 isoprenoid, serves as a critical anchor for the biosynthesis of complex glycans central to bacterial survival and pathogenesis. BPP is formed by the polymerase undecaprenyl pyrophosphate synthase (UppS), which catalyzes the elongation of a single farnesyl diphosphate (FPP) with eight Z-configuration isoprene units from eight isopentenyl diphosphates. In vitro analysis of UppS and other polyprenyl diphosphate synthases requires the addition of a surfactant such as Triton X-100 to stimulate the release of the hydrophobic product from the enzyme for effective and efficient turnover. Here using a fluorescent 2-nitrileanilinogeranyl diphosphate analogue of FPP, we have found that a wide range of surfactants can stimulate release of product from UppS and that the structure of the surfactant has a major impact on the lengths of products produced by the protein. Of particular importance, shorter chain surfactants promote the release of isoprenoids with four to six Z-configuration isoprene additions, while larger chain surfactants promote the formation of natural isoprenoid lengths (8Z) and larger. We have found that the product chain lengths can be readily controlled and coarsely tuned by adjusting surfactant identity, concentration, and reaction time. We have also found that binary mixtures of just two surfactants can be used to fine-tune isoprenoid lengths. The surfactant effects discovered do not appear to be significantly altered with an alternative isoprenoid substrate. However, the surfactant effects do appear to be dependent on differences in UppS between bacterial species. This work provides new insights into surfactant effects in enzymology and highlights how these effects can be leveraged for the chemoenzymatic synthesis of otherwise difficult to obtain glycan biosynthesis probes. This work also provides key reagents for the systematic analysis of structure-activity relationships between glycan

  8. Selective excitation of tryptophan fluorescence decay in proteins using a subnanosecond 295 nm light-emitting diode and time-correlated single-photon counting

    NASA Astrophysics Data System (ADS)

    McGuinness, Colin D.; Sagoo, Kulwinder; McLoskey, David; Birch, David J. S.

    2005-06-01

    We demonstrate an AlGaN light-emitting diode (LED) giving pulses of ˜600ps full width half maximum, 0.35μW average power, 0.6mW peak power, and ˜12nm bandwidth at 295nm. This source is ideal for protein intrinsic tryptophan fluorescence decay research without the unwanted excitation of tyrosine and paves the way to lab-on-a-chip protein assays using fluorescence decay times. Fluorescence decay and anisotropy decay measurements of human serum albumin are reported and the usefulness of the 295nm LED demonstrated in comparisons with a nanosecond flashlamp and LEDs with nominal wavelength emission of 280nm.

  9. Effects of Light and Salinity Stresses in Production of Mycosporine-Like Amino Acids by Gymnodinium catenatum (Dinophyceae).

    PubMed

    Vale, Paulo

    2015-01-01

    Mycosporine-like amino acids (MAAs) were analyzed in a Portuguese Gymnodinium catenatum strain when transferred to high salinity and high light conditions. Total MAA concentrations increased progressively between 30 and 36 psu, attaining at 36 psu 2.9-fold the 30 psu treatment. When abruptly transferred to solar light in an outdoor shadowed location, MAA concentration increased steadily along the day for most compounds. After 8 h, mycosporine-glycine, palythene and M-319 attained or surpassed 25-fold their initial concentration, while M-370 only attained 4-fold concentration. When transferred from halogen to fluorescent light, polar MAAs such as shinorine and porphyra-334, increased until day two and then declined, while M-370 increase slowly, becoming the dominant compound from the profile after 1 week. These experiments put into evidence the relation of palythene with M-319, which was further identified as its acid degradation product, palythine. Acid degradation of M-370 originated M-324, while M-311 seems to be the precursor of M-370. Under high salinity and high light conditions chain formation was altered toward shorter chains or solitary cells. This alteration can represent a morphological stress sign, which in the natural environment could affect average population speed during daily vertical migrations.

  10. Cross-talk between light and glucose regulation controls toxin production and morphogenesis in Aspergillus nidulans.

    PubMed

    Atoui, A; Kastner, C; Larey, C M; Thokala, R; Etxebeste, O; Espeso, E A; Fischer, R; Calvo, A M

    2010-12-01

    Light is a major environmental stimulus that has a broad effect on organisms, triggering a cellular response that results in an optimal adaptation enhancing fitness and survival. In fungi, light affects growth, and causes diverse morphological changes such as those leading to reproduction. Light can also affect fungal metabolism, including the biosynthesis of natural products. In this study we show that in Aspergillus nidulans the effect of light on the production of the sterigmatocystin (ST) toxin depends on the glucose concentration. In cultures grown with 1% glucose and exposed to light, ST production was lower than when grown in the dark. This lower ST production coincided with an elevated rate of cellular damage with partial loss of nuclear integrity and vacuolated cytoplasm. However, in cultures grown with 2% glucose these effects were reversed and light enhanced ST production. Glucose abundance also affected the light-dependent subcellular localization of the VeA (velvet) protein, a key regulator necessary for normal light-dependent morphogenesis and secondary metabolism in Aspergilli and other fungal genera. The role of other VeA-associated proteins, particularly the blue-light-sensing proteins LreA and LreB (WC-1 and WC-2 orthologs), on conidiation could also be modified by the abundance of glucose. We also show that LreA and LreB, as well as the phytochrome FphA, modulate not only the synthesis of sterigmatocystin, but also the production of the antibiotic penicillin.

  11. Fluorescence microscopy image-analysis (FMI) for the characterization of interphase HO˙ production originated by heterogeneous catalysis.

    PubMed

    Zhang, Shuo; Quan, Xie; Wang, Dong

    2017-02-23

    Herein, fluorescence microscopy image-analysis (FMI) visualized the information of interphase HO˙ radicals using luminescent 7-hydroxycoumarin as the marker, revealing the inhomogeneity and intensity of HO˙ production originated by surface-mediated catalysis. The FMI is recommended as a quick-response method for the evaluation of HO˙-assigned heterogeneous catalysis.

  12. Species-specific and seasonal differences in chlorophyll fluorescence and photosynthetic light response among three evergreen species in a Madrean sky island mixed conifer forest

    NASA Astrophysics Data System (ADS)

    Potts, D. L.; Minor, R. L.; Braun, Z.; Barron-Gafford, G. A.

    2012-12-01

    Unlike the snowmelt-dominated hydroclimate of more northern mountainous regions, the hydroclimate of the Madrean sky islands is characterized by snowmelt and convective storms associated with the North American Monsoon. These mid-summer storms trigger biological activity and are important drivers of primary productivity. For example, at the highest elevations where mixed conifer forests occur, ecosystem carbon balance is influenced by monsoon rains. Whereas these storms' significance is increasingly recognized at the ecosystem scale, species-specific physiological responses to the monsoon are poorly known. Prior to and following monsoon onset, we measured pre-dawn and light-adapted chlorophyll fluorescence as well as photosynthetic light response in southwestern white pine (Pinus strobiformis), ponderosa pine (Pinus ponderosa), and Douglas fir (Pseudotsuga menziesii) in a Madrean sky island mixed conifer forest near Tucson, Arizona. Photochemical quenching (qp), an indicator of the proportion of open PSII reaction centers, was greatest in P. strobiformis and least in P. menziesii and increased in response to monsoon rains (repeated-measures ANOVA; species, F2,14 = 6.17, P = 0.012; time, F2,14= 8.17, P = 0.013). In contrast, non-photochemical quenching (qN), an indicator of heat dissipation ability, was greatest in P. ponderosa and least in P. menziesii, but was not influenced by monsoon onset (repeated-measures ANOVA; species, F2,12 = 4.18, P = 0.042). Estimated from leaf area-adjusted photosynthetic light response curves, maximum photosynthetic rate (Amax) was greatest in P. ponderosa and least in P. menziesii (repeated-measures ANOVA; species, F2,8= 40.8, P = 0.001). Surprisingly, while the monsoon positively influenced Amax among P. ponderosa and P. strobiformis, Amax of P. menziesii declined with monsoon onset (repeated-measures ANOVA; species x time, F2,8 = 13.8, P = 0.002). Calculated as the initial slope of the photosynthetic light response curve, light

  13. Photosynthetically supplemental lighting for vegetable crop production with super-bright laser diode

    NASA Astrophysics Data System (ADS)

    Hu, Yongguang; Li, Pingping; Shi, Jintong

    2007-02-01

    Although many artificial light sources like high-pressure sodium lamp, metal halide lamp, fluorescent lamp and so on are commonly used in horticulture, they are not widely applied because of the disadvantages of unreasonable spectra, high cost and complex control. Recently new light sources of light-emitting diode (LED) and laser diode (LD) are becoming more and more popular in the field of display and illumination with the improvement of material and manufacturing, long life-span and increasingly low cost. A new type of super-bright red LD (BL650, central wavelength is 650 nm) was selected to make up of the supplemental lighting panel, on which LDs were distributed with regular hexagon array. Drive circuit was designed to power it and adjust light intensity. System performance including temperature rise and light intensity distribution under different vertical/horizontal distances were tested. Photosynthesis of sweet pepper and eggplant leaf under LD was measured with LI-6400 to show the supplemental lighting effects. The results show that LD system can supply the maximum light intensity of 180 μmol/m2 •s at the distance of 50 mm below the panel and the temperature rise is little within 1 °C. Net photosynthetic rate became faster when LD system increased light intensity. Compared with sunlight and LED supplemental lighting system, LD's promotion on photosynthesis is in the middle. Thus it is feasible for LD light source to supplement light for vegetable crops. Further study would focus on the integration of LD and other artificial light sources.

  14. Transfer of ultraviolet photon energy into fluorescent light in the visible path represents a new and efficient protection mechanism of sunscreens

    NASA Astrophysics Data System (ADS)

    Vergou, Theognosia; Patzelt, Alexa; Richter, Heike; Schanzer, Sabine; Zastrow, Leonhard; Golz, Karin; Doucet, Olivier; Antoniou, Christina; Sterry, Wolfram; Lademann, Juergen

    2011-10-01

    The development of sunscreens with high sun protection factor (SPF) values but low filter concentrations is the ultimate goal. The purpose of the present study was to investigate why a sunscreen spray and cream with different concentrations of the same UV-filters provided the same SPF. Therefore, the homogeneity of the distribution of both sunscreens was investigated by laser scanning microscopy (LSM) and tape stripping (TS). Additionally, the energy transfer mechanisms of the sunscreens on the skin were analyzed. The TS and LSM showed a better homogeneity of the distribution of the spray. With Wood's light, a total absorption of the irradiation was detected in the spray area. In contrast, after cream treatment, an intensive fluorescent signal was observed. It was demonstrated that this fluorescent signal was caused by nonthermal energy transferred from the UV-filters to one compound of the cream releasing its excitation energy by fluorescence. This nonthermal energy transfer seemed to be the reason for the high efficiency of the cream, which is subjected to thermal relaxation. The transfer of UV photon energy into fluorescent light represents a new approach to increase the efficiency of sunscreens and could form the basis for a new generation of sunscreens.

  15. Transfer of ultraviolet photon energy into fluorescent light in the visible path represents a new and efficient protection mechanism of sunscreens.

    PubMed

    Vergou, Theognosia; Patzelt, Alexa; Richter, Heike; Schanzer, Sabine; Zastrow, Leonhard; Golz, Karin; Doucet, Olivier; Antoniou, Christina; Sterry, Wolfram; Lademann, Juergen

    2011-10-01

    The development of sunscreens with high sun protection factor (SPF) values but low filter concentrations is the ultimate goal. The purpose of the present study was to investigate why a sunscreen spray and cream with different concentrations of the same UV-filters provided the same SPF. Therefore, the homogeneity of the distribution of both sunscreens was investigated by laser scanning microscopy (LSM) and tape stripping (TS). Additionally, the energy transfer mechanisms of the sunscreens on the skin were analyzed. The TS and LSM showed a better homogeneity of the distribution of the spray. With Wood's light, a total absorption of the irradiation was detected in the spray area. In contrast, after cream treatment, an intensive fluorescent signal was observed. It was demonstrated that this fluorescent signal was caused by nonthermal energy transferred from the UV-filters to one compound of the cream releasing its excitation energy by fluorescence. This nonthermal energy transfer seemed to be the reason for the high efficiency of the cream, which is subjected to thermal relaxation. The transfer of UV photon energy into fluorescent light represents a new approach to increase the efficiency of sunscreens and could form the basis for a new generation of sunscreens.

  16. Light and exercise and melatonin production in women.

    PubMed

    Knight, Julia A; Thompson, Suzanne; Raboud, Janet M; Hoffman, Barry R

    2005-12-01

    Melatonin may protect against breast cancer. Light and other factors influence melatonin, but the evidence is limited. The authors conducted a study to determine factors related to melatonin. Women volunteers recruited in Toronto, Canada, from 2002 to 2004 collected urine for three nights (winter and summer), took periodic light measurements, and recorded exposures in a diary. The relation of each variable to log-transformed creatinine-corrected 6-sulfatoxymelatonin in overnight urine was determined by use of generalized estimating equation linear regression. The final model was based on 1,054 measurement days from 213 participating women. None of the light variables was related to the log of 6-sulfatoxymelatonin. A significant interaction between season and day length was included in the final model. The most significant factor was duration of exercise (beta = 0.072; p = 0.004, two-tailed), which increased the amount of melatonin produced. Exercise duration later in the day was more significant (beta = 0.108; p = 0.0009, two-tailed). There was no difference between moderate or strenuous exercise. The failure to find a relation between light brightness and melatonin may be due to the difficulty of measuring this, as well as the importance of the light spectrum, which could not be measured. It is possible that the protective effect of exercise with respect to breast cancer may operate in part through an effect on melatonin.

  17. Predicting caries by measuring its activity using quantitative light-induced fluorescence in vivo: a 2-year caries increment analysis.

    PubMed

    Meller, C; Santamaria, R M; Connert, T; Splieth, C

    2012-01-01

    The aim of this study was to analyse the predictive power of several clinical baseline parameters and the de-/remineralisation properties of in vivo etched sites measured with quantitative light-induced fluorescence (QLF) for subsequent 2-year caries increment. At baseline, in 44 children (8.23 ± 1.5 years) two areas (diameter 2 mm) of the buccal surface of a primary posterior tooth were etched with 36% phosphoric acid gel for 1 and 4 min, respectively. The etched sites were analysed immediately after etching (ΔQ1) and 24 h (ΔQ2) later by QLF. Additionally, caries status (deft/DMFT and initial caries), approximal plaque, bleeding on probing, and the patient's current use of fluorides were recorded. In the 2-year follow-up, 29 children were re-assessed. After clinical examination, the caries increment was calculated (ΔDMFT) and correlated with the baseline clinical variables and the QLF readings. Results showed a significant positive correlation between ΔQ(1 min) and the ΔDMFT (r = 0.44, p = 0.02). The ΔDMFT was significantly correlated with the baseline deft (r = 0.56, p = 0.002), cavitated active caries lesions (r = 0.52, p = 0.003), and filled teeth (r = 0.53, p = 0.003). In a regression analysis the use of fluoridated salt (SC = -0.10) and fluoride gel (SC = -0.14) were negatively associated with ΔDMFT. In conclusion, these findings suggest that the demineralisation properties of the etched sites and the outcome of the 24-hour measurements with QLF are significantly associated with caries increment. Previous caries experience strongly correlated with caries increment in this group of children.

  18. 16 CFR 305.15 - Labeling for lighting products.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...; (vi) The ENERGY STAR logo as illustrated in Prototype Label 6 to appendix L for certified products, if... ENERGY STAR logo to labels on certified covered products; such manufacturers or private labelers may add the ENERGY STAR logo to labels only on those products that are covered by the Memorandum...

  19. Highly Automated Module Production Incorporating Advanced Light Management

    SciTech Connect

    Perelli-Minetti, Michael; Roof, Kyle

    2015-08-11

    The objective was to enable a high volume, cost effective solution for increasing the amount of light captured by PV modules through utilization of an advanced Light Re-directing Film and to follow a phased approach to develop and implement this new technology in order to achieve an expected power gain of up to 12 watts per module. Full size PV modules were manufactured using a new Light Redirecting Film (LRF) material applied to two different areas of PV modules in order to increase the amount of light captured by the modules. One configuration involved applying thin strips of LRF film over the tabbing ribbon on the cells in order to redirect the light that is normally absorbed by the tabbing ribbon to the active areas of the cells. A second configuration involved applying thin strips of LRF film over the white spaces between cells within a module in order to capture some of the light that is normally reflected from the white areas back through the front glass of the modules. Significant power increases of 1.4% (3.9 watts) and 1.0% (3.2 watts), respectively, compared to standard PV modules were measured under standard test conditions. The performance of PV modules with LRF applied to the tabbing ribbon was modeled. The results showed that the power increase provided by LRF depended greatly on the angle of incident light with the optimum performance only occurring when the light was within a narrow range of being perpendicular to the solar module. The modeling showed that most of the performance gain would be lost when the angle of incident light was greater than 28 degrees off axis. This effect made the orientation of modules with LRF applied to tabbing ribbons very important as modules mounted in “portrait” mode were predicted to provide little to no power gain from LRF under real world conditions. Based on these results, modules with LRF on tabbing ribbons would have to be mounted in “landscape” mode to realize a performance advantage. In addition

  20. An unexpected negative influence of light intensity on hydrogen production by dark fermentative bacteria Clostridium beijerinckii.

    PubMed

    Zagrodnik, R; Laniecki, M

    2016-01-01

    The role of light intensity on biohydrogen production from glucose by Clostridium beijerinckii, Clostridium acetobutylicum, and Rhodobacter sphaeroides was studied to evaluate the performance and possible application in co-culture fermentation system. The applied source of light had spectrum similar to the solar radiation. The influence of light intensity on hydrogen production in dark process by C. acetobutylicum was negligible. In contrast, dark fermentation by C. beijerinckii bacteria showed a significant decrease (83%) in produced hydrogen at light intensity of 540W/m(2). Here, the redirection of metabolism from acetic and butyric acid formation towards lactic acid was observed. This not yet reported effect was probably caused by irradiation of these bacteria by light within UVA range, which is an important component of the solar radiation. The excessive illumination with light of intensity higher than 200W/m(2) resulted in decrease in hydrogen production with photofermentative bacteria as well.

  1. Production and laser-induced fluorescence spectroscopy (L.I.F.S.) of different Hypericum perforatum L. extracts

    NASA Astrophysics Data System (ADS)

    Skalkos, Dimitris; Filippidis, George; Kapsokalyvas, Dimitris; Meyer, Heiko; Papazoglou, Theodore; Karentzou, Eleni; Dimitriou, Heleni; Kalmanti, M.

    2005-04-01

    We are reporting elsewhere, the promising photodynamic effect of Hypericum perforatum L. extract (PMF) against T24, NBT-II tumor bladder cells, and HL-60 leukemic cells (using 630nm, and 530nm laser light respectively). The main advantages of the extract as a photosensitizer are its low cost, extensive availability, adequate solubility, minimal toxicity, and use with a range of wavelengths. Extraction of dry herb with methanol yields the methanolic extract (ME) in 11%, which is then fractionated using liquid / liquid extraction, yielding the polar methanolic fraction (PMF) in 9,9% overall yield. Hypericin, a photosensitizing ingredient of the herb, was found in these extracts in concentrations as low as 0,51%, and 0,57% respectively. Laser induced fluorescence spectra from the ME and PMF were recorded in order to evaluate their photodiagnostic capacity. An Argon-ion laser was employed for the excitation of the samples. It was shown that the extracts resulted in different fluorescence spectra related both to their intensity, and shape. The intensities of these spectra were only 8 times less compared to the fluorescence of pure hypericin. The dependence of the signal on the pH of the medium of pure hypericin and of PMF was also investigated in order to determine specific spectra variations. According to the results hypericin fluorescence signal fades smoothly in highly acidic medium, while it decreases sharply in highly basic environment. On the contrary PMF gives a slow decrease of fluorescence in both acidic and basic medium. These data suggest that PMF-induced fluorescence is highly sensitive in basic and acidic environment.

  2. 16 CFR 305.15 - Labeling for lighting products.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... When used on the normal line voltage of 120 volts, the light output and energy efficiency are... Appendix L. The text and lines shall be all black or one color type, printed on a white or other neutral... information as illustrated in Prototype Labels 6 in Appendix L; and (F) The minimum font sizes and...

  3. Protoporphyrin IX Functionalised AgSiO2 Core-shell Nanoparticle: Plasmonic Enhancement of Fluorescence and Singlet Oxygen Production.

    PubMed

    Lismont, Marjorie; Dreesen, Laurent; Heinrichs, Benoît; Páez, Carlos A

    2015-12-15

    Metal-enhanced processes arising from the coupling of a dye with metallic nanoparticles (NPs) have been widely reported. However, few studies have simultaneously investigated these mechanisms from the viewpoint of dye fluorescence and photoactivity. Herein, protoporphyrin IX (PpIX) is grafted onto the surface of silver core silica shell NPs in order to investigate the effect of silver (Ag) localised surface plasmon resonance (LSPR) on PpIX fluorescence and PpIX singlet oxygen ((1) O2 ) production. Using two Ag core sizes, we report a systematic study of these photophysical processes as a function of silica (SiO2 ) spacer thickness, LSPR band position and excitation wavelength. The excitation of Ag NP LSPR, which overlaps the PpIX absorption band, leads to the concomitant enhancement of PpIX fluorescence and (1) O2 production independently of the Ag core size, but in a more pronounced way for larger Ag cores. These enhancements result from the increase of the PpIX excitation rate through the LSPR excitation and decrease when the distance between PpIX and Ag NPs increases. A maximum fluorescence enhancement of up to 14-fold, together with an increase of photogenerated (1) O2 production of up to 5 times are obtained using 100 nm Ag cores coated with a 5 nm thick silica coating. This article is protected by copyright. All rights reserved.

  4. X-ray fluorescence analysis of low concentrations metals in geological samples and technological products

    NASA Astrophysics Data System (ADS)

    Lagoida, I. A.; Trushin, A. V.

    2016-02-01

    For the past several years many nuclear physics methods of quantitative elemental analysis have been designed. Many of these methods have applied in different devices which have become useful and effective instrument in many industrial laboratories. Methods of a matter structure analysis are based on the intensity detection of the X-ray radiation from the nuclei of elements which are excited by external X-ray source. The production of characteristic X-rays involves transitions of the orbital electrons of atoms in the target material between allowed orbits, or energy states, associated with ionization of the inner atomic shells. One of these methods is X-ray fluorescence analysis, which is widespread in metallurgical and processing industries and is used to identify and measure the concentration of the elements in ores and minerals on a conveyor belt. Samples of copper ore with known concentrations of elements, were taken from the Ural deposit. To excite the characteristic X-rays radionuclide sources 109Cd, with half-life 461.4 days were used. After finding the calibration coefficients, control measurements of samples and averaging of overall samples were made. The measurement error did not exceed 3%.

  5. The production of consuming less: Energy efficiency, climate change, and light bulbs in North Carolina

    NASA Astrophysics Data System (ADS)

    Thoyre, Autumn

    In this research, I have analyzed the production of consuming less electricity through a case study of promotions of compact fluorescent light bulbs (CFLs). I focused on the CFL because it has been heavily promoted by environmentalists and electricity companies as a key tool for solving climate change, yet such promotions appear counter-intuitive. The magnitude of CFL promotions by environmentalists is surprising because CFLs can only impact less than 1% of U.S. greenhouse gas emissions. CFL promotions by electricity providers are surprising given such companies' normal incentives to sell more of their product. I used political ecological and symbolic interactionist theories, qualitative methods of data collection (including interviews, participant-observation, texts, and images), and a grounded theory analysis to understand this case. My findings suggest that, far from being a self-evident technical entity, energy efficiency is produced as an idea, a part of identities, a resource, and a source of value through social, political, and economic processes. These processes include identity formation and subjectification; gender-coded household labor; and corporate appropriation of household value resulting from environmental governance. I show how environmentalists use CFLs to make and claim neoliberal identities, proposing the concept of green neoliberal identity work as a mechanism through which neoliberal ideologies are translated into practices. I analyze how using this seemingly easy energy efficient technology constitutes labor that is gendered in ways that reflect and reproduce inequalities. I show how electricity companies have used environmental governance to valorize and appropriate home energy efficiency as an accumulation strategy. I conclude by discussing the symbolic power of CFLs, proposing a theory of green obsolescence, and framing the production of energy efficiency as a global production network. I found that promoting energy efficiency involves

  6. LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus

    NASA Astrophysics Data System (ADS)

    Choi, Yong-Keun; Kumaran, Rangarajulu Senthil; Jeon, Hyeon Jin; Song, Hak-Jin; Yang, Yung-Hun; Lee, Sang Hyun; Song, Kyung-Guen; Kim, Kwang Jin; Singh, Vijay; Kim, Hyung Joo

    2015-06-01

    Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2 mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.

  7. LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus.

    PubMed

    Choi, Yong-Keun; Kumaran, Rangarajulu Senthil; Jeon, Hyeon Jin; Song, Hak-Jin; Yang, Yung-Hun; Lee, Sang Hyun; Song, Kyung-Guen; Kim, Kwang Jin; Singh, Vijay; Kim, Hyung Joo

    2015-06-15

    Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.

  8. Biomass and pigments production in photosynthetic bacteria wastewater treatment: effects of light sources.

    PubMed

    Zhou, Qin; Zhang, Panyue; Zhang, Guangming

    2015-03-01

    This study is aimed at enhancing biomass and pigments production together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via different light sources. Red, yellow, blue, white LED and incandescent lamp were used. Results showed different light sources had great effects on the PSB. PSB had the highest biomass production, COD removal and biomass yield with red LED. The corresponding biomass, COD removal and biomass yield reached 2580 mg/L, 88.6% and 0.49 mg-biomass/mg-COD-removal, respectively. The hydraulic retention time of wastewater treatment could be shortened to 72 h with red LED. Mechanism analysis showed higher ATP was produced with red LED than others. Light sources could significantly affect the pigments production. The pigments productions were greatly higher with LED than incandescent lamp. Yellow LED had the highest pigments production while red LED produced the highest carotenoid/bacteriochlorophyll ratio. Considering both efficiency and energy cost, red LED was the optimal light source.

  9. Phytoplankton productivity in relation to light intensity: A simple equation

    USGS Publications Warehouse

    Peterson, D.H.; Perry, M.J.; Bencala, K.E.; Talbot, M.C.

    1987-01-01

    A simple exponential equation is used to describe photosynthetic rate as a function of light intensity for a variety of unicellular algae and higher plants where photosynthesis is proportional to (1-e-??1). The parameter ?? (=Ik-1) is derived by a simultaneous curve-fitting method, where I is incident quantum-flux density. The exponential equation is tested against a wide range of data and is found to adequately describe P vs. I curves. The errors associated with photosynthetic parameters are calculated. A simplified statistical model (Poisson) of photon capture provides a biophysical basis for the equation and for its ability to fit a range of light intensities. The exponential equation provides a non-subjective simultaneous curve fitting estimate for photosynthetic efficiency (a) which is less ambiguous than subjective methods: subjective methods assume that a linear region of the P vs. I curve is readily identifiable. Photosynthetic parameters ?? and a are used widely in aquatic studies to define photosynthesis at low quantum flux. These parameters are particularly important in estuarine environments where high suspended-material concentrations and high diffuse-light extinction coefficients are commonly encountered. ?? 1987.

  10. Fluorescent protein-mediated colour polymorphism in reef corals: multicopy genes extend the adaptation/acclimatization potential to variable light environments.

    PubMed

    Gittins, John R; D'Angelo, Cecilia; Oswald, Franz; Edwards, Richard J; Wiedenmann, Jörg

    2015-01-01

    The genomic framework that enables corals to adjust to unfavourable conditions is crucial for coral reef survival in a rapidly changing climate. We have explored the striking intraspecific variability in the expression of coral pigments from the green fluorescent protein (GFP) family to elucidate the genomic basis for the plasticity of stress responses among reef corals. We show that multicopy genes can greatly increase the dynamic range over which corals can modulate transcript levels in response to the light environment. Using the red fluorescent protein amilFP597 in the coral Acropora millepora as a model, we demonstrate that its expression increases with light intensity, but both the minimal and maximal gene transcript levels vary markedly among colour morphs. The pigment concentration in the tissue of different morphs is strongly correlated with the number of gene copies with a particular promoter type. These findings indicate that colour polymorphism in reef corals can be caused by the environmentally regulated expression of multicopy genes. High-level expression of amilFP597 is correlated with reduced photodamage of zooxanthellae under acute light stress, supporting a photoprotective function of this pigment. The cluster of light-regulated pigment genes can enable corals to invest either in expensive high-level pigmentation, offering benefits under light stress, or to rely on low tissue pigment concentrations and use the conserved resources for other purposes, which is preferable in less light-exposed environments. The genomic framework described here allows corals to pursue different strategies to succeed in habitats with highly variable light stress levels. In summary, our results suggest that the intraspecific plasticity of reef corals' stress responses is larger than previously thought.

  11. The diatom Phaeodactylum tricornutum adjusts nonphotochemical fluorescence quenching capacity in response to dynamic light via fine-tuned Lhcx and xanthophyll cycle pigment synthesis.

    PubMed

    Lepetit, Bernard; Gélin, Gautier; Lepetit, Mariana; Sturm, Sabine; Vugrinec, Sascha; Rogato, Alessandra; Kroth, Peter G; Falciatore, Angela; Lavaud, Johann

    2017-04-01

    Diatoms contain a highly flexible capacity to dissipate excessively absorbed light by nonphotochemical fluorescence quenching (NPQ) based on the light-induced conversion of diadinoxanthin (Dd) into diatoxanthin (Dt) and the presence of Lhcx proteins. Their NPQ fine regulation on the molecular level upon a shift to dynamic light conditions is unknown. We investigated the regulation of Dd + Dt amount, Lhcx gene and protein synthesis and NPQ capacity in the diatom Phaeodactylum tricornutum after a change from continuous low light to 3 d of sine (SL) or fluctuating (FL) light conditions. Four P. tricornutum strains with different NPQ capacities due to different expression of Lhcx1 were included. All strains responded to dynamic light comparably, independently of initial NPQ capacity. During SL, NPQ capacity was strongly enhanced due to a gradual increase of Lhcx2 and Dd + Dt amount. During FL, cells enhanced their NPQ capacity on the first day due to increased Dd + Dt, Lhcx2 and Lhcx3; already by the second day light acclimation was accomplished. While quenching efficiency of Dt was strongly lowered during SL conditions, it remained high throughout the whole FL exposure. Our results highlight a more balanced and cost-effective photoacclimation strategy of P. tricornutum under FL than under SL conditions.

  12. Implications of Increasing Light Tight Oil Production for U.S. Refining

    EIA Publications

    2015-01-01

    EIA retained Turner, Mason & Company to provide analysis of the implications of increasing domestic light tight oil production for U.S. refining, focusing on regional crude supply/demand balances, refinery crude slates, operations, capital investment, product yields, crude oil exports/imports, petroleum product exports, infrastructure constraints and expansions, and crude oil price relationships.

  13. Emergency Lighting

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A lighting system originally developed for NASA's Apollo and Skylab manned spacecraft resulted in a industrial spinoff and creation of a whole new company to produce and market the product line. The company is UDEC Corp., Waltham, Mass. UDEC's "Multi-Mode" electronic lighting systems are designed for plant emergency and supplemental use, such as night lighting, "always-on" stairwell lights and illuminated exit signs. Their advantages stem from the qualities demanded for spacecraft installation: extremely high fight output with very low energy drain, compactness, light weight, and high reliability. The Multi-Mode system includes long-life fluorescent lamps operated by electronic circuitry, a sealed battery that needs no maintenance for 10 years, and a solid-state battery charger. A typical emergency installation consists of a master module with battery and an eight watt lamp, together with four remote "Satellight" modules powered by the master's battery. As a night lighting system for maintenance or I security, UDEC fixtures can bypass the battery and 1 operate on normal current at a fraction of the energy 1 demand of conventional night lighting. Industrial customers have realized savings of better than ninety percent with UDEC night lights. UDEC started as a basement industry in 1972 but the company has already sold more than 1,000 lighting systems to building operators.

  14. Luminescent photobioreactor design for improved algal growth and photosynthetic pigment production through spectral conversion of light.

    PubMed

    Mohsenpour, Seyedeh Fatemeh; Willoughby, Nik

    2013-08-01

    Growth characteristics of two strains of microalgae in bubble column photobioreactors were investigated under different cultivation conditions. Chlorella vulgaris and Gloeothece membranacea were cultivated in luminescent acrylic photobioreactors at different seed culture densities. Luminescent acrylic photobioreactors in blue, green, yellow, orange, and red colours capable of spectral conversion of light were used. The results indicated that the red luminescent photobioreactor enhanced biomass production in both strains of microalgae while pigmentation was induced under different light colours. Green light promoted chlorophyll production in C. vulgaris however chlorophyll production in G. membranacea cultures was less influenced by the light condition or culture density. Phycobiliproteins were the dominant pigments in G. membranacea and red light favoured synthesis of these pigments.

  15. Ultraviolet light exposure, skin cancer risk and vitamin D production

    PubMed Central

    RIVAS, MIGUEL; ROJAS, ELISA; ARAYA, MARÍA C.; CALAF, GLORIA M.

    2015-01-01

    The danger of overexposure to solar ultraviolet radiation has been widely reviewed since the 1980s due to the depletion of the ozone layer. However, the benefits of mild exposure of the skin to ultraviolet (UV) light have not been widely investigated. Numerous reports have demonstrated that an association exists between low light exposure to the sun, non-melanoma skin cancer and a lack of vitamin D synthesis. As vitamin D synthesis in the body depends on skin exposure to UVB radiation from the sun (wavelength, 290–320 nm), experimental measurements for this type of solar radiation are important. The present study analyzed data obtained from a laboratory investigating UV radiation from the sun at the University of Tarapacá (Arica, Chile), where systematic experimental UVB measurements had been performed using a calibrated biometer instrument since 2006. These data were compared with skin cancer data from the local population. The results demonstrated that the incidence of skin cancer systematically increased from 7.4 to 18.7 in men and from 10.0 to 21.7 in women between 2000 and 2006 in Arica, respectively; this increase may be due to multiple factors, including the lack of adequate levels of vitamin D in risk groups such as post-menopausal women and senior age. This marked increase may also be due to the high levels of UV radiation measured in this region throughout the year. However, it is not certain that the local population has adequate vitamin D levels, nor that their skin has been predominantly exposed to artificial light that does not allow adequate vitamin D synthesis. Thus, the current study presents the association between skin type IV, the time to induce solar erythema and the time required to produce 1,000 international units of vitamin D. PMID:26622830

  16. Ultraviolet light exposure, skin cancer risk and vitamin D production.

    PubMed

    Rivas, Miguel; Rojas, Elisa; Araya, María C; Calaf, Gloria M

    2015-10-01

    The danger of overexposure to solar ultraviolet radiation has been widely reviewed since the 1980s due to the depletion of the ozone layer. However, the benefits of mild exposure of the skin to ultraviolet (UV) light have not been widely investigated. Numerous reports have demonstrated that an association exists between low light exposure to the sun, non-melanoma skin cancer and a lack of vitamin D synthesis. As vitamin D synthesis in the body depends on skin exposure to UVB radiation from the sun (wavelength, 290-320 nm), experimental measurements for this type of solar radiation are important. The present study analyzed data obtained from a laboratory investigating UV radiation from the sun at the University of Tarapacá (Arica, Chile), where systematic experimental UVB measurements had been performed using a calibrated biometer instrument since 2006. These data were compared with skin cancer data from the local population. The results demonstrated that the incidence of skin cancer systematically increased from 7.4 to 18.7 in men and from 10.0 to 21.7 in women between 2000 and 2006 in Arica, respectively; this increase may be due to multiple factors, including the lack of adequate levels of vitamin D in risk groups such as post-menopausal women and senior age. This marked increase may also be due to the high levels of UV radiation measured in this region throughout the year. However, it is not certain that the local population has adequate vitamin D levels, nor that their skin has been predominantly exposed to artificial light that does not allow adequate vitamin D synthesis. Thus, the current study presents the association between skin type IV, the time to induce solar erythema and the time required to produce 1,000 international units of vitamin D.

  17. Designing inorganic light-protective skin nanotechnology products.

    PubMed

    Popov, Alexey P; Zvyagin, Andrei V; Lademann, Juergen; Roberts, Michael S; Sanchez, Washington; Priezzhev, Alexander V; Myllylä, Risto

    2010-10-01

    In this review, we discuss the use of inorganic nanoparticles, mainly zinc oxide (ZnO) and titanium dioxide (TiO2), for sunscreen applications considering their intrinsic physical properties and the Mie theory. These properties cause, from one side, attenuation of the ultraviolet light by absorption and scattering (dependent on a particle size), which is the purpose sunscreens are designed for, and formation of free radicals (i.e., phototoxicity) during this process--from the other. Particle penetration into skin is also an important issue addressed in this review due to possible adverse effects associated with interaction between nanoparticles and skin living cells.

  18. A direct and simultaneous detection of zinc protoporphyrin IX, free protoporphyrin IX, and fluorescent heme degradation product in red blood cell hemolysates.

    PubMed

    Chen, Qiuying; Hirsch, Rhoda Elison

    2006-03-01

    Fluorescence emission of free protoporphyrin IX (PPIX, em. approximately 626 nm), zinc protoporphyrin IX (ZPP, em. approximately 594 nm) and fluorescent heme degradation product (FHDP, em. approximately 466 nm) are identified and simultaneously detected in mouse and human red cell hemolysates, when excited at 365 nm. A novel method is established for comparing relative FHDP, PPIX and ZPP levels in hemolysates without performing red cell porphyrin extractions. The ZPP fluorescence directly measured in hemolysates (F(365/594)) correlates with the ZPP fluorescence obtained from acetone/water extraction (R(2) = 0.9515, P < 0.0001). The relative total porphyrin (ZPP and PPIX) fluorescence obtained from direct hemolysate fluorescence measurements also correlates with red blood cell total porphyrins determined by ethyl acetate extraction (Piomelli extraction, R(2) = 0.88, P < 0.0001). These fluorescent species serves as biomarkers for alterations in Hb synthesis and Hb stability.

  19. Far-red/near-infrared fluorescence light-up probes for specific in vitro and in vivo imaging of a tumour-related protein.

    PubMed

    Chen, Chao; Hua, Yongquan; Hu, Yawen; Fang, Yuan; Ji, Shenglu; Yang, Zhimou; Ou, Caiwen; Kong, Deling; Ding, Dan

    2016-03-17

    As lysosomal protein transmembrane 4 beta (LAPTM4B) is an important biomarker for many solid tumours, development of small-molecule fluorescence light-up probes for detection and imaging of LAPTM4B proteins is particularly valuable. In this work, we reported the design and synthesis of a far-red/near-infrared (FR/NIR) fluorescence light-up probe DBT-2EEGIHGHHIISVG, which could specifically visualize LAPTM4B proteins in cancer cells and tumour-bearing live mice. DBT-2EEGIHGHHIISVG was synthesized by the conjugation of two LAPTM4B-binding peptide ligands (EEGIHGHHIISVG) with one environment-sensitive fluorogen, 4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole (DBT). Owing to the intramolecular charge transfer character of DBT, DBT-2EEGIHGHHIISVG is weakly emissive in aqueous solution, but switches to fluoresce upon LAPTM4B proteins specifically bind to the peptide ligand of the probe, which provide the DBT with hydrophobic microenvironment, greatly reducing its charge transfer effect with water. It is found that DBT-2EEGIHGHHIISVG can achieve targeted imaging of LAPTM4B proteins in HepG2 cancer cells and visualize LAPTM4B protein-expressed tumour tissues of live mice in a selective and high-contrast manner.

  20. Far-red/near-infrared fluorescence light-up probes for specific in vitro and in vivo imaging of a tumour-related protein

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Hua, Yongquan; Hu, Yawen; Fang, Yuan; Ji, Shenglu; Yang, Zhimou; Ou, Caiwen; Kong, Deling; Ding, Dan

    2016-03-01

    As lysosomal protein transmembrane 4 beta (LAPTM4B) is an important biomarker for many solid tumours, development of small-molecule fluorescence light-up probes for detection and imaging of LAPTM4B proteins is particularly valuable. In this work, we reported the design and synthesis of a far-red/near-infrared (FR/NIR) fluorescence light-up probe DBT-2EEGIHGHHIISVG, which could specifically visualize LAPTM4B proteins in cancer cells and tumour-bearing live mice. DBT-2EEGIHGHHIISVG was synthesized by the conjugation of two LAPTM4B-binding peptide ligands (EEGIHGHHIISVG) with one environment-sensitive fluorogen, 4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole (DBT). Owing to the intramolecular charge transfer character of DBT, DBT-2EEGIHGHHIISVG is weakly emissive in aqueous solution, but switches to fluoresce upon LAPTM4B proteins specifically bind to the peptide ligand of the probe, which provide the DBT with hydrophobic microenvironment, greatly reducing its charge transfer effect with water. It is found that DBT-2EEGIHGHHIISVG can achieve targeted imaging of LAPTM4B proteins in HepG2 cancer cells and visualize LAPTM4B protein-expressed tumour tissues of live mice in a selective and high-contrast manner.

  1. Far-red/near-infrared fluorescence light-up probes for specific in vitro and in vivo imaging of a tumour-related protein

    PubMed Central

    Chen, Chao; Hua, Yongquan; Hu, Yawen; Fang, Yuan; Ji, Shenglu; Yang, Zhimou; Ou, Caiwen; Kong, Deling; Ding, Dan

    2016-01-01

    As lysosomal protein transmembrane 4 beta (LAPTM4B) is an important biomarker for many solid tumours, development of small-molecule fluorescence light-up probes for detection and imaging of LAPTM4B proteins is particularly valuable. In this work, we reported the design and synthesis of a far-red/near-infrared (FR/NIR) fluorescence light-up probe DBT-2EEGIHGHHIISVG, which could specifically visualize LAPTM4B proteins in cancer cells and tumour-bearing live mice. DBT-2EEGIHGHHIISVG was synthesized by the conjugation of two LAPTM4B-binding peptide ligands (EEGIHGHHIISVG) with one environment-sensitive fluorogen, 4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole (DBT). Owing to the intramolecular charge transfer character of DBT, DBT-2EEGIHGHHIISVG is weakly emissive in aqueous solution, but switches to fluoresce upon LAPTM4B proteins specifically bind to the peptide ligand of the probe, which provide the DBT with hydrophobic microenvironment, greatly reducing its charge transfer effect with water. It is found that DBT-2EEGIHGHHIISVG can achieve targeted imaging of LAPTM4B proteins in HepG2 cancer cells and visualize LAPTM4B protein-expressed tumour tissues of live mice in a selective and high-contrast manner. PMID:26984064

  2. Use of edible coatings to preserve quality of lightly (and slightly) processed products.

    PubMed

    Baldwin, E A; Nisperos-Carriedo, M O; Baker, R A

    1995-11-01

    Lightly processed agricultural products present a special problem to the food industry and to scientists involved in postharvest and food technology research. Light or minimal processing includes cutting, slicing, coring, peeling, trimming, or sectioning of agricultural produce. These products have an active metabolism that can result in deteriorative changes, such as increased respiration and ethylene production. If not controlled, these changes can lead to rapid senescence and general deterioration of the product. In addition, the surface water activity of cut fruits and vegetables is generally quite high, inviting microbial attack, which further reduces product stability. Methods for control of these changes are numerous and can include the use of edible coatings. Also mentioned in this review are coating of nut products, and dried, dehydrated, and freeze-dried fruits. Technically, these are not considered to be minimally processed, but many of the problems and benefits of coating these products are similar to coating lightly processed products. Generally, the potential benefits of edible coatings for processed or lightly processed produce is to stabilize the product and thereby extend product shelf life. More specifically, coatings have the potential to reduce moisture loss, restrict oxygen entrance, lower respiration, retard ethylene production, seal in flavor volatiles, and carry additives that retard discoloration and microbial growth.

  3. QM/MM study on the light emitters of aequorin chemiluminescence, bioluminescence, and fluorescence: a general understanding of the bioluminescence of several marine organisms.

    PubMed

    Chen, Shu-Feng; Ferré, Nicolas; Liu, Ya-Jun

    2013-06-24

    Aequorea victoria is a type of jellyfish that is known by its famous protein, green fluorescent protein (GFP), which has been widely used as a probe in many fields. Aequorea has another important protein, aequorin, which is one of the members of the EF-hand calcium-binding protein family. Aequorin has been used for intracellular calcium measurements for three decades, but its bioluminescence mechanism remains largely unknown. One of the important reasons is the lack of clear and reliable knowledge about the light emitters, which are complex. Several neutral and anionic forms exist in chemiexcited, bioluminescent, and fluorescent states and are connected with the H-bond network of the binding cavity in the protein. We first theoretically investigated aequorin chemiluminescence, bioluminescence, and fluorescence in real proteins by performing hybrid quantum mechanics and molecular mechanics methods combined with a molecular dynamics method. For the first time, this study reported the origin and clear differences in the chemiluminescence, bioluminescence and fluorescence of aequorin, which is important for understanding the bioluminescence not only of jellyfish, but also of many other marine organisms (that have the same coelenterazine caved in different coelenterazine-type luciferases).

  4. Image-Guided Sentinel Lymph Node Mapping and Nanotechnology-Based Nodal Treatment in Lung Cancer using Invisible Near-Infrared Fluorescent Light

    PubMed Central

    Khullar, Onkar; Frangioni, John V.; Colson, Yolonda L.

    2011-01-01

    Current methods for sentinel lymph node (SLN) mapping and nodal treatment in lung cancer remain inadequate for routine clinical use. Here we discuss the potential for using the combination of invisible near-infrared (NIR) fluorescent light and nanotechnology for these applications. NIR fluorescence imaging has recently received significant attention for in vivo imaging applications because of its low tissue autofluorescence, high photon penetration into living tissue, and high signal-to-background ratio. Our large animal in vivo studies have been able to successfully identify sentinel lymph nodes in lung tissue and several clinical studies have examined the use of NIR fluorescence imaging systems for SLN mapping in breast and gastric cancer. Promising new nanoparticle technologies, when combined with NIR fluorescence imaging, offer the potential for image-guided treatment of lymph nodes at high risk for tumor recurrence. This review provides a theoretical and empirical framework for developing the next-generation of diagnostic and therapeutic agents for lung cancer. PMID:20226343

  5. Solar light-induced production of reactive oxygen species by single walled carbon nanotubes in water

    EPA Science Inventory

    Photosensitizing processes of engineered nanomaterials (ENMs) which include photo-induced production of reactive oxygen species (ROS) convert light energy into oxidizing chemical energy that mediates transformations of nanomaterials. The oxidative stress associated with ROS may p...

  6. Biomass and carotenoid production in photosynthetic bacteria wastewater treatment: effects of light intensity.

    PubMed

    Zhou, Qin; Zhang, Panyue; Zhang, Guangming

    2014-11-01

    This study investigated the feasibility of using photosynthetic bacteria (PSB) to produce biomass and carotenoid while treating wastewater. The effects of light intensity on the biomass, carotenoid and bacteriochlorophyll accumulation in together with pollutant removal were studied. Results showed that it was feasible to use PSB to treat wastewater as well as to produce biomass or carotenoid. 2000 lux was an optimal intensity for biomass production and COD removal, and the corresponding values were 2645 mg/L and 94.7%. 8000 lux was an optimal light intensity for carotenoid production (1.455 mg/L). Mechanism analysis displayed that the greater the bacteriochlorophyll and carotenoid were secreted, the lower the light conversion efficiency turned out to be. The highest light conversion efficiency was achieved at 500 lux; the ATP production, biomass production, and COD removal were the highest at 2000 lux, but the bacteriochlorophyll and carotenoid content were the lowest at 2000 lux.

  7. Production of Ultra-Light Normal Incidence Mirrors

    NASA Technical Reports Server (NTRS)

    Jones, Ruth; Muntele, Iulia; Muntele, Claudiu; Zimmerman, Robert L.; Ila, Daryush; Burdine, Robert V. (Technical Monitor)

    2002-01-01

    Mirrors fabrication for large aperture telescopes is an important aspect in space exploration programs. One of the cost effective techniques to obtain such mirrors is electroplating of Ni-Co alloys from sulfamate solution. The Center for Irradiation of Materials at Alabama A&M University - Research Institute has been involved in a NASA-MSFC project for producing ultra-light Ni-Co alloy mirrors since the summer of year 2000. The goal of this project is to obtain ultra-light, high strength electroformed large aperture normal incidence replicated mirrors, (weighting less than 5 kg/m2), free of stress, with a good figure and reproducible thickness variation. In order to simplify the control of parameters such as temperature gradient, concentration gradient, distribution of the electric field lines and flow control, the proposed geometry involves a cylindrical main tank contained in another cylindrical tank, which plays the role of a weir. Designs were created to accommodate the new horizontal position of the mandrel and the pipes fitting through the outer tank's lid. The inner tank contains the working electrodes and a series of sensors for monitoring temperature, flow, stress and pH. The outer tank holds the electric heaters, the filters and a part of the piping system. Another two tanks complete the setup and serve for rinsing/preheating and equilibrating the electroplating bath. This paper will describe advantages of the new experimental setup and the parameters achieved in the electroplating bath for the proposed geometry.

  8. The influence of light intensity and photoperiod on duckweed biomass and starch accumulation for bioethanol production.

    PubMed

    Yin, Yehu; Yu, Changjiang; Yu, Li; Zhao, Jinshan; Sun, Changjiang; Ma, Yubin; Zhou, Gongke

    2015-01-01

    Duckweed has been considered as a valuable feedstock for bioethanol production due to its high biomass and starch production. To investigate the effects of light conditions on duckweed biomass and starch production, Lemna aequinoctialis 6000 was cultivated at different photoperiods (12:12, 16:8 and 24:0h) and light intensities (20, 50, 80, 110, 200 and 400μmolm(-2)s(-1)). The results showed that the duckweed biomass and starch production was increased with increasing light intensity and photoperiod except at 200 and 400μmolm(-2)s(-1). Considering the light cost, 110μmolm(-2)s(-1) was optimum light condition for starch accumulation with the highest maximum growth rate, biomass and starch production of 8.90gm(-2)day(-1), 233.25gm(-2) and 98.70gm(-2), respectively. Moreover, the results suggested that high light induction was a promising method for duckweed starch accumulation. This study provides optimized light conditions for future industrial large-scale duckweed cultivation.

  9. Consistency Between Sun-Induced Chlorophyll Fluorescence and Gross Primary Production of Vegetation in North America

    NASA Technical Reports Server (NTRS)

    Zhang, Yao; Xiao, Xiangming; Jin, Cui; Dong, Jinwei; Zhou, Sha; Wagle, Pradeep; Joiner, Joanna; Guanter, Luis; Zhang, Yongguang; Zhang , Geli; Qin, Yuanwei; Wang, Jie; Moore, Berrien, III

    2016-01-01

    Accurate estimation of the gross primary production (GPP) of terrestrial ecosystems is vital for a better understanding of the spatial-temporal patterns of the global carbon cycle. In this study,we estimate GPP in North America (NA) using the satellite-based Vegetation Photosynthesis Model (VPM), MODIS (Moderate Resolution Imaging Spectrometer) images at 8-day temporal and 500 meter spatial resolutions, and NCEP-NARR (National Center for Environmental Prediction-North America Regional Reanalysis) climate data. The simulated GPP (GPP (sub VPM)) agrees well with the flux tower derived GPP (GPPEC) at 39 AmeriFlux sites (155 site-years). The GPP (sub VPM) in 2010 is spatially aggregated to 0.5 by 0.5-degree grid cells and then compared with sun-induced chlorophyll fluorescence (SIF) data from Global Ozone Monitoring Instrument 2 (GOME-2), which is directly related to vegetation photosynthesis. Spatial distribution and seasonal dynamics of GPP (sub VPM) and GOME-2 SIF show good consistency. At the biome scale, GPP (sub VPM) and SIF shows strong linear relationships (R (sup 2) is greater than 0.95) and small variations in regression slopes ((4.60-5.55 grams Carbon per square meter per day) divided by (milliwatts per square meter per nanometer per square radian)). The total annual GPP (sub VPM) in NA in 2010 is approximately 13.53 petagrams Carbon per year, which accounts for approximately 11.0 percent of the global terrestrial GPP and is within the range of annual GPP estimates from six other process-based and data-driven models (11.35-22.23 petagrams Carbon per year). Among the seven models, some models did not capture the spatial pattern of GOME-2 SIF data at annual scale, especially in Midwest cropland region. The results from this study demonstrate the reliable performance of VPM at the continental scale, and the potential of SIF data being used as a benchmark to compare with GPP models.

  10. Healthy Dietary Patterns and Oxidative Stress as Measured by Fluorescent Oxidation Products in Nurses’ Health Study

    PubMed Central

    Jung, Seungyoun; Smith-Warner, Stephanie A.; Willett, Walter C.; Wang, Molin; Wu, Tianying; Jensen, Majken; Hankinson, Susan E.; Eliassen, A. Heather

    2016-01-01

    Healthy diets may lower oxidative stress and risk of chronic diseases. However, no previous studies examined associations between diet and fluorescent oxidation products (FlOP), a global marker of oxidative stress. We evaluated associations between healthy eating patterns (Alternative Healthy Eating Index (AHEI), Dietary Approach to Stop Hypertension (DASH), and Alternate Mediterranean Diet (aMED)) and FlOP, measured at three excitation/emission wavelengths (FlOP_360, FlOP_320, FlOP_400) from 2021 blood samples collected from 1688 women within the Nurses’ Health Study. AHEI, DASH, and aMED scores were significantly positively associated with FlOP_360 and FlOP_320 concentrations (p-trend ≤ 0.04), but not associated with FlOP_400. Among specific food groups that contribute to these diet scores, significantly positive associations were observed with legumes and vegetables for FlOP_360, vegetables and fruits for FlOP_320, and legumes and alcohol for FlOP_400. Inverse associations were observed with nuts, sweets or desserts, and olive oil for FlOP_360, nuts for FlOP_320 and sweets or desserts for FlOP_400 (all p-trend ≤ 0.05). However, FlOP variation due to diet was small compared to overall FlOP variation. In conclusion, AHEI, DASH, and aMED scores were unexpectedly positively, but weakly, associated with FlOP_360 and FlOP_320. However, these findings should be interpreted cautiously as the determinants of FlOP concentrations are not fully understood. PMID:27657128

  11. Daily light use efficiency in a cornfield can be related to the canopy red/far-red fluorescence ratio and leaf light use efficiency across a growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In multiple years (2008-2013), we collected canopy and leaf fluorescence, photosynthesis, hyperspectral reflectance spectra, and biophysical measurements along transects within a USDA/Beltsville experimental cornfield treated with optimal nitrogen application (100%N) and which has an eddy covariance...

  12. Probing the micellization kinetics of pyrene end-labeled diblock copolymer via a combination of stopped-flow light-scattering and fluorescence techniques.

    PubMed

    Zhang, Jingyan; Li, Yuting; Armes, Steven P; Liu, Shiyong

    2007-10-25

    A pyrene end-labeled double hydrophilic diblock copolymer, poly(2-(diethylamino)ethyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (Py-PDEA-b-PDMA), was synthesized by sequential monomer addition via oxyanionic polymerization using a 1-pyrenemethanol-based initiator. This diblock copolymer exhibits reversible pH-responsive micellization behavior in aqueous solution, forming PDEA-core micelles stabilized by the soluble PDMA block at neutral or alkaline pH. Taking advantage of the pyrene probe covalently attached to the end of the PDEA block, the pH-induced micellization kinetics of Py-PDEA-b-PDMA was monitored by stopped-flow light scattering using a fluorescence detector. Upon a pH jump from 4.0 to 9.0, both the scattered light intensity and excimer/monomer fluorescence intensity ratios (IE/IM) increase abruptly initially, followed by a more gradual increase to reach plateau values. Interestingly, the IE/IM ratio increases abruptly within the first 10 ms: a triple exponential function is needed to fit the corresponding dynamic trace, leading to three characteristic relaxation time constants (tau(1,fluo) < tau(2,fluo) < tau(3,fluo)). On the other hand, dynamic traces for the scattered light intensity can be well-fitted by double exponential functions: the resulting time constants tau(1,scat) and tau(2,scat) can be ascribed to formation of the quasi-equilibrium micelles and relaxation into their final equilibrium state, respectively. Most importantly, tau(1,scat) obtained from stopped-flow light scattering is in general agreement with tau(2,fluo) obtained from stopped-flow fluorescence. The fastest process (tau(1,fluo) approximately 4 ms) detected by stopped-flow fluorescence is ascribed to the burst formation of small transient micelles comprising only a few chains, which are too small to be detected by conventional light scattering. These nascent micelles undergo rapid fusion and grow into quasi-equilibrium micelles and then slowly approach their final

  13. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2010-08-03

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  14. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen R.; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2009-01-06

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  15. A new on-axis micro-spectrophotometer for combining Raman, fluorescence and UV/Vis absorption spectroscopy with macromolecular crystallography at the Swiss Light Source.

    PubMed

    Pompidor, Guillaume; Dworkowski, Florian S N; Thominet, Vincent; Schulze-Briese, Clemens; Fuchs, Martin R

    2013-09-01

    The combination of X-ray diffraction experiments with optical methods such as Raman, UV/Vis absorption and fluorescence spectroscopy greatly enhances and complements the specificity of the obtained information. The upgraded version of the in situ on-axis micro-spectrophotometer, MS2, at the macromolecular crystallography beamline X10SA of the Swiss Light Source is presented. The instrument newly supports Raman and resonance Raman spectroscopy, in addition to the previously available UV/Vis absorption and fluorescence modes. With the recent upgrades of the spectral bandwidth, instrument stability, detection efficiency and control software, the application range of the instrument and its ease of operation were greatly improved. Its on-axis geometry with collinear X-ray and optical axes to ensure optimal control of the overlap of sample volumes probed by each technique is still unique amongst comparable facilities worldwide and the instrument has now been in general user operation for over two years.

  16. A new on-axis micro-spectrophotometer for combining Raman, fluorescence and UV/Vis absorption spectroscopy with macromolecular crystallography at the Swiss Light Source

    PubMed Central

    Pompidor, Guillaume; Dworkowski, Florian S. N.; Thominet, Vincent; Schulze-Briese, Clemens; Fuchs, Martin R.

    2013-01-01

    The combination of X-ray diffraction experiments with optical methods such as Raman, UV/Vis absorption and fluorescence spectroscopy greatly enhances and complements the specificity of the obtained information. The upgraded version of the in situ on-axis micro-spectrophotometer, MS2, at the macromolecular crystallography beamline X10SA of the Swiss Light Source is presented. The instrument newly supports Raman and resonance Raman spectroscopy, in addition to the previously available UV/Vis absorption and fluorescence modes. With the recent upgrades of the spectral bandwidth, instrument stability, detection efficiency and control software, the application range of the instrument and its ease of operation were greatly improved. Its on-axis geometry with collinear X-ray and optical axes to ensure optimal control of the overlap of sample volumes probed by each technique is still unique amongst comparable facilities worldwide and the instrument has now been in general user operation for over two years. PMID:23955041

  17. Rational design, synthesis, and spectroscopic and photophysical properties of a visible-light-excitable, ratiometric, fluorescent near-neutral pH indicator based on BODIPY.

    PubMed

    Boens, Noël; Qin, Wenwu; Baruah, Mukulesh; De Borggraeve, Wim M; Filarowski, Aleksander; Smisdom, Nick; Ameloot, Marcel; Crovetto, Luis; Talavera, Eva M; Alvarez-Pez, Jose M

    2011-09-19

    A visible-light-excitable, ratiometric, brightly fluorescent pH indicator for measurements in the pH range 5-7 has been designed and synthesized by conjugatively linking the BODIPY fluorophore at the 3-position to the pH-sensitive ligand imidazole through an ethenyl bridge. The probe is available as cell membrane permeable methyl ester 8-(4-carbomethoxyphenyl)-4,4-difluoro-3-[2-(1H-imidazol-4-yl)ethenyl]-1,5,7-trimethyl-3a,4a-diaza-4-bora-s-indacene (I) and corresponding water-soluble sodium carboxylate, sodium 8-(4-carboxylatophenyl)-4,4-difluoro-3-[2-(1H-imidazol-4-yl)ethenyl]-1,5,7-trimethyl-3a,4a-diaza-4-bora-s-indacene (II). The fluorescence quantum yield Φ(f) of ester I is very high (0.8-1.0) in the organic solvents tested. The fluorescence lifetime (ca. 4 ns) of I in organic solvents with varying polarity/polarizability (from cyclohexane to acetonitrile) is independent of the solvent with a fluorescence rate constant k(f) of 2.4×10(8) s(-1). Probe I is readily loaded in the cytosol of live cells, where its high fluorescence intensity remains nearly constant over an extended time period. Water-soluble indicator II exhibits two acid-base equilibria in aqueous solution, characterized by pK(a) values of 6.0 and 12.6. The Φ(f) value of II in aqueous solution is high: 0.6 for the cationic and anionic forms of the imidazole ligand, and 0.8 for neutral imidazole. On protonation-deprotonation in the near-neutral pH range, UV/Vis absorption and fluorescence spectral shifts along with isosbestic and pseudo-isoemissive points are observed. This dual-excitation and dual-emission pH indicator emits intense green-yellow fluorescence at lower pH and intense orange fluorescence at higher pH. The influence of ionic strength and buffer concentration on the absorbance and steady-state fluorescence of II has also been investigated. The apparent pK(a) of the near-neutral acid-base equilibrium determined by spectrophotometric and fluorometric titration is nearly independent of

  18. Effect of short-time hydrothermal pretreatment of kitchen waste on biohydrogen production: fluorescence spectroscopy coupled with parallel factor analysis.

    PubMed

    Li, Mingxiao; Xia, Tianming; Zhu, Chaowei; Xi, Beidou; Jia, Xuan; Wei, Zimin; Zhu, Jinlong

    2014-11-01

    The enhancement of bio-hydrogen production from kitchen waste by a short-time hydrothermal pretreatment at different temperatures (i.e., 90°C, 120°C, 150°C and 200°C) was evaluated. The effects of temperature for the short-time hydrothermal pretreatment on kitchen waste protein conversion and dissolved organic matter characteristics were investigated in this study. A maximum bio-hydrogen yield of 81.27mL/g VS was acquired at 200°C by the short-time hydrothermal pretreatment during the anaerobic fermentative hydrogen production. Analysis of the dissolved organic matter composition showed that the protein-like peak dominated and that three fluorescent components were separated using fluorescence excitation-emission matrix spectra coupled with the parallel factor model. The maximum fluorescence intensities of protein-like components decomposed through the parallel factor analysis has a significant correlation with the raw protein concentration, showed by further correlation analysis. This directly impacted the hydrogen production ability.

  19. Digital video technology and production 101: lights, camera, action.

    PubMed

    Elliot, Diane L; Goldberg, Linn; Goldberg, Michael J

    2014-01-01

    Videos are powerful tools for enhancing the reach and effectiveness of health promotion programs. They can be used for program promotion and recruitment, for training program implementation staff/volunteers, and as elements of an intervention. Although certain brief videos may be produced without technical assistance, others often require collaboration and contracting with professional videographers. To get practitioners started and to facilitate interactions with professional videographers, this Tool includes a guide to the jargon of video production and suggestions for how to integrate videos into health education and promotion work. For each type of video, production principles and issues to consider when working with a professional videographer are provided. The Tool also includes links to examples in each category of video applications to health promotion.

  20. Quantitative modeling of Cerenkov light production efficiency from medical radionuclides.

    PubMed

    Beattie, Bradley J; Thorek, Daniel L J; Schmidtlein, Charles R; Pentlow, Keith S; Humm, John L; Hielscher, Andreas H

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use.

  1. Advanced lighting guidelines: 1993. Final report

    SciTech Connect

    Eley, C.; Tolen, T.M.; Benya, J.R.; Rubinstein, F.; Verderber, 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 Halide 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.

  2. Determination of free amino acids in African gourd seed milks by capillary electrophoresis with light-emitting diode induced fluorescence and laser-induced fluorescence detection.

    PubMed

    Enzonga, Josiane; Ong-Meang, Varravaddheay; Couderc, François; Boutonnet, Audrey; Poinsot, Véréna; Tsieri, Michel Mvoula; Silou, Thomas; Bouajila, Jalloul

    2013-09-01

    A CE technique coupled to LIF detection (488 nm) or LED-induced fluorescence detection (470 nm) has been evaluated to acquire a cheap way to analyze amino acids (AAs) whilst maintaining the best sensitivity. To quantitate AAs in milk of Cucurbitaceae of Sub-Saharan Africa, they were labeled with FITC. We used an optimized separation buffer composed of 30 mM boric acid buffer adjusted to pH 9.3 with NaOH (1 M) containing 12 mM SDS and 5% ethylene glycol v/v; prior to the injections, the derivatized samples are diluted 100 times. The LOQs in the sample are Arg: 1.1 μM, Ala: 3.5 μM, and Glu 8.9 μM. Cucumeropsis mannii (CM) Naudin and Citrullus lanatus (CL) are vegetable sources rich in proteins and AAs of high quality. Our analyses have led to the identification of 11 AAs in CL and CM milks. Phe, Trp, and Ala are predominant in the two types of lyophilized milks, while Asp and Val demonstrate very low contents. Six essential AAs (Phe, Thr, Val, Trp, Ile, and Leu) are present in both types of extracts, but lysine was not detected, indicating that this AA is missing in gourd milk. These results should be useful in efforts to complement or replace very expensive cow milk or the less-appreciated soya milk with milk from available local agroressources.

  3. Light

    NASA Astrophysics Data System (ADS)

    Vernon, C. G.

    2016-09-01

    Preface; 1. Historical; 2. Waves and wave-motion; 3. The behaviour of ripples; 4. The behaviour of light; 5. Refraction through glass blocks and prisms; 6. The imprinting of curvatures; 7. Simple mathematical treatment; 8. More advanced mathematical treatment; 9. The velocity of light; 10. The spectrum and colour; 11. Geometrical optics; 12. The eye and optical instruments; 13. Sources of light; 14. Interference, diffraction and polarisation; 15. Suggestions for class experiments; Index.

  4. Above 20% external quantum efficiency in novel hybrid white organic light-emitting diodes having green thermally activated delayed fluorescent emitter

    PubMed Central

    Kim, Bo Seong; Yook, Kyoung Soo; Lee, Jun Yeob

    2014-01-01

    High efficiency hybrid type white organic light-emitting diodes (WOLEDs) combining a green thermally activated delayed fluorescent (TADF) emitting material with red/blue phosphorescent emitting materials were developed by manipulating the device architecture of WOLEDs. Energy transfer between a blue phosphorescent emitting material and a green TADF emitter was efficient and could be managed by controlling the doping concentration of emitters. A high quantum efficiency above 20% was achieved in the hybrid WOLEDs by optimizing the device structure of the hybrid type WOLEDs for the first time and the device performances of the hybrid WOLEDs were comparable to those of all phosphorescent WOLEDs. PMID:25317855

  5. Influence of dehydrated nanotubed titanic acid on charge transport and luminescent properties of polymer light-emitting diodes with fluorescent dye

    NASA Astrophysics Data System (ADS)

    Qian, Lei; Bera, Debasis; Jin, Zhen-Sheng; Du, Zu-Liang; Xu, Zheng; Teng, Feng; Liu, Wei

    2007-09-01

    In this paper, we discuss the influence of dehydrated nanotubed titanic acid (DNTA) on charge transport and luminescent properties of polymer light-emitting diodes (PLEDs) doped with fluorescent dye. Photoluminescence results confirm the efficient energy transfer from PVK to 4-(dicyanom-ethylene)-2- t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) and tris-(8-hydroxtquinoline) aluminum (Alq 3) in a DNTA-doped device. The device showed lower turn-on voltages and higher charge current by doping with DNTA, which also caused a shift in the exciton's recombination region.

  6. Above 20% external quantum efficiency in novel hybrid white organic light-emitting diodes having green thermally activated delayed fluorescent emitter

    NASA Astrophysics Data System (ADS)

    Kim, Bo Seong; Yook, Kyoung Soo; Lee, Jun Yeob

    2014-08-01

    High efficiency hybrid type white organic light-emitting diodes (WOLEDs) combining a green thermally activated delayed fluorescent (TADF) emitting material with red/blue phosphorescent emitting materials were developed by manipulating the device architecture of WOLEDs. Energy transfer between a blue phosphorescent emitting material and a green TADF emitter was efficient and could be managed by controlling the doping concentration of emitters. A high quantum efficiency above 20% was achieved in the hybrid WOLEDs by optimizing the device structure of the hybrid type WOLEDs for the first time and the device performances of the hybrid WOLEDs were comparable to those of all phosphorescent WOLEDs.

  7. Production of light oil by injection of hot inert gas

    NASA Astrophysics Data System (ADS)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2016-05-01

    Hot inert gas, when injected into an oil reservoir is capable of generating a vaporization-condensation drive and as a consequence, a preferential movement of the lighter components to the production well. This form of displacement is an important unit mechanism in hot flue-gas injection, or in thermal recovery from a watered-out oil reservoir. This article presents the movement of heat front vis-à-vis the changes in the saturation profile, and the gas-phase composition. The plateau in the temperature profile due to the exchange of latent heat, and the formation of water bank at the downstream are elaborated. The broadening of the vaporization-condensation zone with continued progression is discussed. The effect of inert gas temperature on the cumulative production of oil is reviewed. The results provide insight to the vaporization-condensation drive as a stand-alone mechanism. The paper underscores the relative importance of this mechanism, when operated in tandem with other processes in improved oil recovery and CO2 sequestration.

  8. Quantitative Modeling of Cerenkov Light Production Efficiency from Medical Radionuclides

    PubMed Central

    Beattie, Bradley J.; Thorek, Daniel L. J.; Schmidtlein, Charles R.; Pentlow, Keith S.; Humm, John L.; Hielscher, Andreas H.

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use. PMID:22363636

  9. Non-UV light influences the degradation rate of crop protection products.

    PubMed

    Davies, Lawrence O; Bramke, Irene; France, Emma; Marshall, Samantha; Oliver, Robin; Nichols, Carol; Schäfer, Hendrik; Bending, Gary D

    2013-08-06

    Crop protection products (CPPs) are subject to strict regulatory evaluation, including laboratory and field trials, prior to approval for commercial use. Laboratory tests lack environmental realism, while field trials are difficult to control. Addition of environmental complexity to laboratory systems is therefore desirable to mimic a field environment more effectively. We investigated the effect of non-UV light on the degradation of eight CPPs (chlorotoluron, prometryn, cinosulfuron, imidacloprid, lufenuron, propiconazole, fludioxonil, and benzovindiflupyr) by addition of non-UV light to standard OECD 307 guidelines. Time taken for 50% degradation of benzovindiflupyr was halved from 373 to 183 days with the inclusion of light. Similarly, time taken for 90% degradation of chlorotoluron decreased from 79 to 35 days under light conditions. Significant reductions in extractable parent compound occurred under light conditions for prometryn (4%), imidacloprid (8%), and fludioxonil (24%) compared to dark controls. However, a significantly slower rate of cinosulfuron (14%) transformation was observed under light compared to dark conditions. Under light conditions, nonextractable residues were significantly higher for seven of the CPPs. Soil biological and chemical analyses suggest that light stimulates phototroph growth, which may directly and/or indirectly impact CPP degradation rates. The results of this study strongly suggest that light is an important parameter affecting CPP degradation, and inclusion of light into regulatory studies may enhance their environmental realism.