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Sample records for light chemical effects

  1. Chemical and size effects of hygroscopic aerosols on light scattering coefficients

    NASA Astrophysics Data System (ADS)

    Tang, Ignatius N.

    1996-08-01

    The extensive thermodynamic and optical properties recently reported [Tang and Munkelwitz, 1994a] for sulfate and nitrate solution droplets are incorporated into a visibility model for computing light scattering by hygroscopic aerosols. The following aerosol systems are considered: NH4HSO4, (NH4)2SO4, (NH4)3H(SO4), NaHSO4, Na2SO4, NH4NO3, and NaNO3. In addition, H2SO4 and NaCl are included to represent freshly formed sulfate and background sea-salt aerosols, respectively. Scattering coefficients, based on 1 μg dry salt per cubic meter of air, are calculated as a function of relative humidity for aerosols of various chemical compositions and lognormal size distributions. For a given size distribution the light scattered by aerosol particles per unit dry-salt mass concentration is only weakly dependent on chemical constituents of the hygroscopic sulfate and nitrate aerosols. Sulfuric acid and sodium chloride aerosols, however, are exceptions and scatter light more efficiently than all other inorganic salt aerosols considered in this study. Both internal and external mixtures exhibit similar light-scattering properties. Thus for common sulfate and nitrate aerosols, since the chemical effect is outweighed by the size effect, it follows that observed light scattering by the ambient aerosol can be approximated, within practical measurement uncertainties, by assuming the aerosol being an external mixture. This has a definite advantage for either visibility degradation or climatic impact modeling calculations, because relevant data are now available for external mixtures but only very scarce for internal mixtures.

  2. Chemical and sensory effects of storing sauvignon Blanc wine in colored bottles under artificial light.

    PubMed

    Cáceres-Mella, Alejandro; Flores-Valdivia, Daniela; Laurie, V Felipe; López-Solís, Remigio; Peña-Neira, Álvaro

    2014-07-23

    The chemical and sensory effects of storing Sauvignon Blanc in colored bottles and exposing them to artificial light were examined. The colors of the bottles chosen were Dead Leaf Green, Antique Green, Amber, and Flint. The light was provided by fluorescent tubes with a regime of 16 h of exposure during 8 months of storage. The results indicated that the wine's chemical composition was affected by the type of bottle used. The Flint bottle presented the lowest concentration of total phenols. Yellow coloration was not dependent on the bottle color, as the wine in darker bottles (Amber, Antique Green, and Dead Leaf Green) had considerably more yellow color development than the wine in clear bottles. With regard to the sensory analyses performed, a trend showing an increase in color intensity and a decrease in overall aromas depending on the bottle color was observed. The wine's aromatic description changed significantly during its storage under artificial light conditions, demonstrating a decrease in vegetal aromas and an increase in citrus and tropical flavors that was dependent on the bottle color. PMID:24983902

  3. Tetracene films for light-emitting transistors: chemical and physical effects of the organic dielectric substrates

    NASA Astrophysics Data System (ADS)

    Santato, Clara; Cicoira, Fabio; Bertolazzi, Simone

    2010-03-01

    Tetracene vacuum-sublimed films have been used to demonstrate the first Organic Light Emitting Field Effect Transistor (OLEFET), in 2003. Because of their planar configuration, OLEFET are excellent systems to study fundamental processes such as charge injection, transport, and light emission in organic semiconductor films. OLEFET are intensively investigated for applications in active matrix full-color displays and, ultimately, lasers. Since the first Tetracene-OLEFET, a number of excellent studies have been reported on vacuum-sublimed as well as solution-processed films of organic semiconductors incorporated into OLEFET. Investigating the role played by the surface substrate chemistry and establishing sound structure-property relationships in organic semiconductor films incorporated into OLEFET structures are the keys to understand and improve the optoelectronic characteristics of OLEFET. Here we present our results on the morphological, structural, light-emission, and charge transport properties in field-effect transistor configuration of vacuum-sublimed tetracene films deposited on chemically and physically different organic dielectric substrates (HMDS- and OTS-treated SiO2, polystyrene, parylene, PMMA).

  4. Green light radiation effects on free radicals inhibition in cellular and chemical systems.

    PubMed

    Comorosan, Sorin; Polosan, Silviu; Jipa, Silviu; Popescu, Irinel; Marton, George; Ionescu, Elena; Cristache, Ligia; Badila, Dumitru; Mitrica, Radu

    2011-01-10

    Free radicals generation is inhibited through green light (GL) irradiation in cellular systems and in chemical reactions. Standard melanocyte cultures were UV-irradiated and the induced cellular reactive oxygen species (ROS) were quantified by the fluorescence technique. The same cell cultures, previously protected by a 24h GL exposure, displayed a significantly lower ROS production. A simple chemical reaction is subsequently chosen, in which the production of free radicals is well defined. Paraffin wax and mineral oil were GL irradiated during thermal degradation and the oxidation products checked by chemiluminescence [CL] and Fourier transform infrared spectra [FT-IR]. The same clear inhibition of the radical oxidation of alkanes is recorded. A quantum chemistry modeling of these results is performed and a mechanism involving a new type of Rydberg macromolecular systems with implications for biology and medicine is suggested. PMID:20934350

  5. Infrared light actuated shape memory effects in crystalline polyurethane/graphene chemical hybrids

    NASA Astrophysics Data System (ADS)

    Park, J. H.; Kim, B. K.

    2014-02-01

    A series of crystalline shape memory polyurethanes (SMPUs) were synthesized from polycaprolactone diols and 4,4‧-methylenedicyclohexyl diisocyanate (H12MDI) with chemical incorporation of allyl isocyanate modified graphene oxide (iGO) into the PU. Actuation of hybrid SMPUs by infrared (IR) absorption of iGO as well as the direct heat actuated SMPUs has been studied in terms of the isothermal crystallization rate, near-IR absorption, and thermal, mechanical, and shape memory properties. It was found that iGO functions as a multifunctional cross-linker at low contents and a nucleating agent at high contents, and as a reinforcing filler, while light absorption by the iGO induced melting of the PU soft segment, giving rise to a shape recovery of over 90% at 1% iGO (G10).

  6. Relativistic environmental effects in (29)Si NMR chemical shifts of halosilanes: light nucleus, heavy environment.

    PubMed

    Fedorov, Sergey V; Rusakov, Yury Yu; Krivdin, Leonid B

    2015-06-01

    Relativistic calculations of (29)Si NMR shielding constants (chemical shifts) in the series of halosilanes SiX(n)H(4-n) (X = F, Cl, Br and I) are performed within a full four-component relativistic Dirac's scheme using relativistic Dyall's basis sets. Three different theoretical levels are tested in the computation of (29)Si NMR chemical shifts in comparison with experiment: namely, four-component relativistic GIAO-DFT, four-component relativistic GIAO-RPA, and a hybrid scheme of a nonrelativistic GIAO-MP2 with taking into account relativistic corrections using the four-component relativistic GIAO-RPA. The DFT results give larger relativistic effects as compared to the RPA data which might be rationalized in terms of the manifestation of correlation effects taken into account at the DFT level and not accounted for at the uncorrelated RPA level. Taking into account solvent effects slightly improves agreement with experiment, however, being not a matter of principle. Generally, relativistic pure nonempirical wave function methods perform much better as compared to relativistic DFT methods when benchmarked to experiment. PMID:25946056

  7. Functionalized Nanoparticles and Surfaces for Controlled Chemical Catalysis and Effective Light Harvesting

    SciTech Connect

    Marye Anne Fox, James K. Whitesell

    2012-11-02

    We have prepared a range of such arrays as key components for biotechnology and photonic applications. These involve self-assembled arrays of increasing complexity with three-dimensionally disposed multilayer interactions. These arrays also include dendrimers as the distinguishing structural building blocks. These photoactive integrated systems have a regular, highly-branched, three-dimensional architecture. Structural modifications of these units include variation of the core, bridging layers, and terminal groups. These modifications result in a large array of dendritic molecules with potential applications for light harvesting.

  8. Effect of ultraviolet light irradiation and sandblasting treatment on bond strengths between polyamide and chemical-cured resin.

    PubMed

    Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

    2014-01-01

    The aim of this study was to evaluate the effects of ultraviolet light (UV) irradiation and sandblasting treatment on the shear bond strength between polyamide and chemical-cured resin. Three types of commercial polyamides were treated using UV irradiation, sandblasting treatment, and a combining sandblasting and UV irradiation. The shear bond strength was measured and analyzed using the Kruskal-Wallis test (α=0.05). Comparing shear bond strengths without surface treatment, from 4.1 to 5.7 MPa, the UV irradiation significantly increased the shear bond strengths except for Valplast, whose shear bond strengths ranged from 5.2 to 9.3 MPa. The sandblasting treatment also significantly increased the shear bond strengths (8.0 to 11.4 MPa). The combining sandblasting and UV irradiation significantly increased the shear bond strengths (15.2 to 18.3 MPa) comparing without surface treatment. This combined treatment was considered the most effective at improving the shear bond strength between polyamide and chemical-cured resin. PMID:25087663

  9. Effect of smokeless tobacco and tobacco-related chemical carcinogens on survival of ultraviolet light-inactivated herpes simplex virus

    SciTech Connect

    Dokko, H.; Min, P.S.; Cherrick, H.M.; Park, N.H. )

    1991-04-01

    Low doses of ultraviolet (UV) light, x-rays, photodynamic treatment, or aflatoxins increase the survival of UV-irradiated virus in cells. This effect is postulated to occur by enhancement of the error-prone cellular repair function, which could also be associated with oncogenic cell transformation. The present study was designed to investigate whether treatment of green monkey kidney cells with water extract of snuff (snuff extract), benzo(a)pyrene, nicotine, or tobacco-specific N'-nitrosamines would result in enhanced survival of UV-irradiated herpes simplex virus (HSV). Exposure of the cells with snuff extract, benzo(a)pyrene, N'-nitrosonornicotine, or 4-(N-methyl-N'-nitrosamino)-1-(3-pyridyl)-1-butanone resulted in an enhancement of survival of UV-irradiated HSV type 1 compared with the control whereas exposure of the cells with nicotine did not. These data indicate that the water-extractable component of snuff and tobacco-related chemical carcinogens increase the cellular repair mechanism and provides for increased survival of UV-irradiated HSV.

  10. Effect of monochromatic light stimuli during embryogenesis on muscular growth, chemical composition, and meat quality of breast muscle in male broilers.

    PubMed

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

    2012-04-01

    This study was conducted to evaluate the effect of monochromatic light stimuli during embryogenesis on breast muscle growth, chemical composition, and meat quality of male broilers. Fertile broiler eggs (Arbor Acres; n = 1,320) were preweighed and randomly assigned to 1 of 3 treatment groups in 3 modified incubators: 1) control group (in dark condition), 2) monochromatic green light group (560 nm), and 3) monochromatic blue light group (480 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. After hatch, 120 male chicks from each group were placed in 6 replicates with 20 birds each. All of the birds were housed under white light (30 lx at bird-head level) with a light schedule of 23L:1D. At 21, 35, and 42 d of age, BW and breast muscle weight in the green light group were significantly increased compared with birds in the blue or dark groups (P < 0.05). The breast muscle weight and breast muscle percentages in birds incubated under green light were significantly elevated by 50.39 g (0.76%) and 54.07 g (1.20%) than those in the dark condition or blue group at 42 d of market age (P < 0.05), respectively. In the green light group, feed intake during 0~42 d was higher than that in the other 2 treatment groups (P < 0.05); feed conversion ratio during 0~35 and 0~42 d were lower than that in the dark condition (P < 0.05). No significant differences in the contents of breast moisture, CP, crude fat, and crude ash among all groups were observed (P > 0.05). Green light stimuli tended to increase cooking loss (P = 0.08) and L* value of 24-h meat color (P = 0.09). These results suggest that green light stimuli during embryogenesis enhanced the posthatch BW of male broilers, increased breast muscle growth, and improved the feed conversion ratio, but it did not cause any noticeable changes in breast chemical composition or overall meat quality characteristics. PMID:22399743

  11. Fine particulate chemical composition and light extinction at Meadview, AZ.

    PubMed

    Eatough, Delbert J; Cui, Wenxuan; Hull, Jeffery; Farber, Robert J

    2006-12-01

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr day-night samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was +/- 0.6 microg/m3 organic material, +/- 0.3 microg/m3 ammonium sulfate, and +/- 0.07 microg/m3 ammonium nitrate. Data were also available on fine particulate crustal material, fine and coarse particulate mass from the Interagency Monitoring of Protected Visual Environments sampling system, and relative humidity (RH), light absorption, particle scattering, and light extinction measurements from Project MOHAVE. An extinction budget was obtained using mass scattering coefficients estimated from particle size distribution data. Literature data were used to estimate the change in the mass scattering coefficients for the measured species as a function of RH and for the absorption of light by elemental carbon. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. During periods of highest light extinction, contributions from fine particulate organic material, sulfate, and light-absorbing carbon dominated the extinction of light by particles. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides

  12. Neuroendocrine effects of light

    NASA Astrophysics Data System (ADS)

    Reiter, Russel J.

    1991-09-01

    The light/dark cycle to which animals, and possibly humans, are exposed has a major impact on their physiology. The mechanisms whereby specific tissues respond to the light/dark cycle involve the pineal hormone melatonin. The pineal gland, an end organ of the visual system in mammals, produces the hormone melatonin only at night, at which time it is released into the blood. The duration of elevated nightly melatonin provides every tissue with information about the time of day and time of year (in animals that are kept under naturally changing photoperiods). Besides its release in a circadian mode, melatonin is also discharged in a pulsatile manner; the physiological significance, if any, of pulsatile melatonin release remains unknown. The exposure of animals including man to light at night rapidly depresses pineal melatonin synthesis and, therefore, blood melatonin levels drop precipitously. The brightness of light at night required to depress melatonin production is highly species specific. In general, the pineal gland of nocturnally active mammals, which possess rod-dominated retinas, is more sensitive to inhibition by light than is the pineal gland of diurnally active animals (with cone-dominated retinas). Because of the ability of the light/dark cycle to determine melatonin production, the photoperiod is capable of influencing the function of a variety of endocrine and non-endocrine organs. Indeed, melatonin is a ubiquitously acting pineal hormone with its effects on the neuroendocrine system having been most thoroughly investigated. Thus, in nonhuman photoperiodic mammals melatonin regulates seasonal reproduction; in humans also, the indole has been implicated in the control of reproductive physiology.

  13. EFFECTS OF CHEMICAL PROCESSING AND OXIDE ETHYLENE STERILIZATION ON CORTICAL AND CANCELLOUS RAT BONE: A LIGHT AND ELECTRON SCANNING MICROSCOPY STUDY

    PubMed Central

    Castiglia, Marcello Teixeira; da Silva, Juliano Voltarelli F.; Frezarim Thomazini, José Armendir; Volpon, José Batista

    2015-01-01

    To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. Methods: Samples of cancellous and cortical bones obtained from young female albinus rats (Wistar) were assigned to four groups according to the type of treatment: Group I- drying; Group II- drying and ethylene oxide sterilization; III- chemical treatment; IV- chemical treatment and ethylene oxide sterilization. Half of this material was analyzed under ordinary light microscope and the other half using scanning electron microscopy. Results: In all the samples, regardless the group, there was good preservation of the general morphology. For samples submitted to the chemical processing there was better preservation of the cellular content, whereas there was amalgamation of the fibres when ethylene oxide was used. Conclusion: Treatment with ethylene oxide caused amalgamation of the fibers, possibly because of heating and the chemical treatment contributed to a better cellular preservation of the osseous structure. PMID:26998450

  14. Fine particulate chemical composition and light extinction at Meadview, AZ

    SciTech Connect

    Delbert J. Eatough; Wenxuan Cui; Jeffery Hull; Robert J. Farber

    2006-12-15

    The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr daynight samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was {+-} 0.6 {mu}g/m{sup 3} organic material, {+-} 0.3 {mu}g/m{sup 3} ammonium sulfate, and {+-} 0.07 {mu}g/m{sup 3} ammonium nitrate. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides sources in the region indicate that the major anthropogenic contributors to light extinction were from the Los Angeles, CA, and Las Vegas, NV, urban areas. Mohave Power Project associated secondary sulfate was a negligible contributor to light extinction. 49 refs., 12 figs., 7 tabs.

  15. Chemically enhanced bacteriorhodopsin thin-film spatial-light modulator

    NASA Astrophysics Data System (ADS)

    Song, Qi Wang; Zhang, Chunping; Blumer, Robert V.; Gross, Richard B.; Chen, Zhongping; Birge, Robert R.

    1994-01-01

    An optically addressed spatial light modulator that is based on the chemically enhanced bacteriorhodopsin thin film is demonstrated. The underlying principle is the light-induced shift of absorption band of the protein. The device can be chemically or genetically modified for different applications. In our preliminary experiment, a resolution of about 100 line pairs per millimeter with a linear dynamic range of above 100:1 is obtained.

  16. Chemically enhanced bacteriorhodopsin thin-film spatial light modulator

    NASA Astrophysics Data System (ADS)

    Song, Q. W.; Zhang, Chungping; Blumer, Robert; Gross, Richard B.; Chen, Zhongping; Birge, Robert R.

    1993-08-01

    An optically addressed spatial light modulator based on a thin film of chemically enhanced bacteriorhodopsin is demonstrated. Incoherent-to-coherent light conversion is achieved by exploitation of both the large shift in absorption maxima accompanying the bR - M phototransformation and the extended M-intermediate lifetime resulting from the chemical enhancement of the protein at high pH. The device exhibits a linear dynamic range of 120:1 at 514 nm and a resolution of about 100 line pairs/mm.

  17. Chemical physics: Quantum control of light-induced reactions

    NASA Astrophysics Data System (ADS)

    Chandler, David W.

    2016-07-01

    An investigation of how ultracold molecules are broken apart by light reveals surprising, previously unobserved quantum effects. The work opens up avenues of research in quantum optics. See Letter p.122

  18. High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes

    SciTech Connect

    Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M

    2011-03-01

    Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.

  19. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Optical strength of mirrors on fluorite substrates subjected to cw radiation from a chemical CO laser

    NASA Astrophysics Data System (ADS)

    Dudkin, V. A.; Rukhin, V. B.

    1994-02-01

    Optimisation of the energy characteristics of a chemical CO laser revealed damage to the optical resonator mirrors. Estimates indicated that when the power density of the incident cw laser radiation was 2-2.5 kW cm-2 the induced thermoelastic stresses could reach the damage threshold of mirrors on fluorite substrates.

  20. Detection of UV light based on chemically stimulated luminescence of crystal phosphors

    NASA Astrophysics Data System (ADS)

    Grankin, D. V.; Grankin, V. P.; Martysh, M. A.

    2016-06-01

    High-efficiency accommodation of heterogeneous-reaction energy via an electronic channel and the possibility of using this effect to design an ionizing (UV) radiation detector based on chemically stimulated luminescence have been investigated. Preliminary irradiation of a ZnS sample by UV light is found to cause a luminescence flash under subsequent exposure of the sample surface to a flux of hydrogen atoms. The flash intensity depends on the UV excitation level and increases by several orders of magnitude in comparison with an unirradiated sample. It is shown that a new method for detecting UV light using chemically stimulated luminescence of crystal phosphors accumulating light yield can be developed based on this effect.

  1. Health effects of chemical products.

    PubMed

    Steensberg, J

    1982-01-01

    An outline is given of the data on human health effects that are needed as a foundation for the administration of legislation on chemical substances and products. Danish data on mortality and morbidity from acute poisoning and some published clinical studies are presented. Serious problems may persist in subgroups of the population and the prevention of acute poisoning is still a basic aim of this legislation. Allergic reactions to chemicals are discussed. Not all sensitized individuals can be protected but steps should be taken to prevent contact with the sensitizing agents that are of the greatest public health importance. Chronic health effects following exposure to chemicals have influenced the recent strengthening of regulations but carcinogenic risks especially are extremely difficult for administrative and political systems to handle in an approximately rational way. While we are reducing the use of suspected carcinogenic chemicals our populations must, however, be given a greater appreciation of the cancer risk problem, particularly the fact that we cannot eliminate all cancer risks. Biological monitoring of human populations is a necessary supplement to the traditional registration of diseases as part of our health surveillance systems. Fortunately our societies have been able to pay increasing attention to the long-term public health consequences of exposures to chemical factors in our environment. PMID:6236969

  2. Chemical Imaging of Biological Tissue with Synchrotron Infrared Light

    SciTech Connect

    Miller,L.; Dumas, P.

    2006-01-01

    Fourier transform infrared micro-spectroscopy (FTIRM) and imaging (FTIRI) have become valuable techniques for examining the chemical makeup of biological materials by probing their vibrational motions on a microscopic scale. Synchrotron infrared (S-IR) light is an ideal source for FTIRM and FTIRI due to the combination of its high brightness (i.e., flux density), also called brilliance, and broadband nature. Through a 10-{mu}m pinhole, the brightness of a synchrotron source is 100-1000 times higher than a conventional thermal (globar) source. Accordingly, the improvement in spatial resolution and in spectral quality to the diffraction limit has led to a plethora of applications that is just being realized. In this review, we describe the development of synchrotron-based FTIRM, illustrate its advantages in many applications to biological systems, and propose some potential future directions for the technique.

  3. Light-induced chemical vapour deposition painting with titanium dioxide

    NASA Astrophysics Data System (ADS)

    Halary-Wagner, E.; Bret, T.; Hoffmann, P.

    2003-03-01

    Light-induced chemical vapour deposits of titanium dioxide are obtained from titanium tetra-isopropoxide (TTIP) in an oxygen and nitrogen atmosphere with a long pulse (250 ns) 308 nm XeCl excimer laser using a mask projection set-up. The demonstrated advantages of this technique are: (i) selective area deposition, (ii) precise control of the deposited thickness and (iii) low temperature deposition, enabling to use a wide range of substrates. A revolving mask system enables, in a single reactor load, to deposit shapes of controlled heights, which overlap to build up a complex pattern. Interferential multi-coloured deposits are achieved, and the process limitations (available colours and resolution) are discussed.

  4. Ship diesel emission aerosols: A comprehensive study on the chemical composition, the physical properties and the molecular biological and toxicological effects on human lung cells of aerosols from a ship diesel engine operated with heavy or light diesel fuel oil

    NASA Astrophysics Data System (ADS)

    Zimmermann, R.; Buters, J.; Öder, S.; Dietmar, G.; Kanashova, T.; Paur, H.; Dilger, M.; Mülhopt, S.; Harndorf, H.; Stengel, B.; Rabe, R.; Hirvonen, M.; Jokiniemi, J.; Hiller, K.; Sapcariu, S.; Berube, K.; Sippula, O.; Streibel, T.; Karg, E.; Schnelle-Kreis, J.; Lintelmann, J.; Sklorz, M.; Arteaga Salas, M.; Orasche, J.; Müller, L.; Reda, A.; Passig, J.; Radischat, C.; Gröger, T.; Weiss, C.

    2013-12-01

    The Virtual Helmholtz Institute-HICE (www.hice-vi.eu) addresses chemical & physical properties, transformation processes and health effects of anthropogenic combustion emissions. This is performed by thorough comprehensive chemical and physical characterization of combustion aerosols (including application of advantageous on-line methods) and studying of biological effects on human lung cell-cultures. A new ALI air-liquid-interface (ALI) exposition system and a mobile S2-biological laboratory were developed for the HICE-measurements. Human alveolar basal epithelial cells (A549 etc.) are ALI-exposed to fresh, diluted (1:40-1:100) combustion aerosols and subsequently were toxicologically and molecular-biologically characterized (e.g. proteomics). By using stable isotope labeling technologies (13C-Glucose/metabolomics; 2H-Lysine/SILAC-proteomics), high sensitivity and accuracy for detection of molecular-biological effects is achievable even at sub-toxic effect dose levels. Aerosols from wood combustion and ship diesel engine (heavy/light fuel oil) have been investigated. The effect of wood combustion and ship diesel PM e.g. on the protein expression of ALI-exposed A549 cells was compared. Filtered aerosol is used as gas-reference for the isotope labeling based method (SILAC). Therefore the effects of wood combustion- and shipping diesel-PM can be directly compared. Ship diesel aerosol causes a broader distribution in the observed fold changes (log2), i.e. more proteins are significantly up-/down-regulated in case of shipping diesel PM-exposure. This corresponds to a stronger biological reaction if compared to wood combustion-PM exposure. The chemical analysis results on wood combustion- and ship diesel-PM depict more polycyclic aromatic hydrocarbons (PAH)/oxidized-PAH but less of some transition metals (V, Fe) in the wood combustion case. Interestingly, alkylated PAH are considerably more abundant in shipping PM, suggesting that PAH/Oxy-PAH may be less relevant for

  5. Controlling charge transport in blue organic light-emitting devices by chemical functionalization of host materials

    SciTech Connect

    Polikarpov, Evgueni; Koech, Phillip K.; Wang, Liang; Swensen, James S.; Cosimbescu, Lelia; Rainbolt, James E.; Von Ruden, Amber L.; Gaspar, Daniel J.; Padmaperuma, Asanga B.

    2011-01-18

    Generation of white light from OLEDs for general lighting applications requires a highly efficient blue component. However, a stable and power efficient blue OLED component with simple device architecture remains a significant challenge partly due to lack of appropriate host materials. Here we report the photophysical and device properties of ambipolar host phosphine oxide based materials. In this work, we studied the effect of the structural modification made to phosphine oxide-based hosts on the charge balance. We observed significant changes in charge transport within the host occurred upon small modifications to their chemical structure. As a result, an alteration of the chemical design of these materials allows for the control of charge balance of the OLED.

  6. Effect of chemical peeling on photocarcinogenesis.

    PubMed

    Abdel-Daim, Mohamed; Funasaka, Yoko; Kamo, Tsuneyoshi; Ooe, Masahiko; Matsunaka, Hiroshi; Yanagita, Emmy; Itoh, Tomoo; Nishigori, Chikako

    2010-10-01

    Chemical peeling is one of the dermatological treatments available for certain cutaneous diseases and conditions or improvement of cosmetic appearance of photo-aged skin. We assessed the photo-chemopreventive effect of several clinically used chemical peeling agents on the ultraviolet-irradiated skin of hairless mice. Chemical peeling was done using 35% glycolic acid dissolved in distilled water, 30% salicylic acid in ethanol, and 10% or 35% trichloroacetic acid in distilled water at the right back of ultraviolet-irradiated hairless mice every 2 weeks for glycolic acid, salicylic acid and 10% trichloroacetic acid, and every 4 weeks for 35% trichloroacetic acid for a total of 18 weeks after the establishment of photo-aged mice by irradiation with ultraviolet B range light three times a week for 14 weeks at a total dose of 6.66 J/cm(2) . Tumor formation was assessed every week. Skin specimens were taken from treated and non-treated area for evaluation under microscopy, evaluation of p53 expression and mRNA expression of cyclooxygenase-2. Serum level of prostaglandin E(2) was also evaluated. All types of chemical peeling reduced tumor formation in treated mice, mostly in the treated area but also in the non-treated area. Peeling suppressed retention of p53-positive abnormal cells and reduced mRNA expression of cyclooxygenase-2 in treated skin. Further, serum prostaglandin E(2) level was decreased in chemical peeling treated mice. These results indicate that chemical peeling with glycolic acid, salicylic acid and trichloroacetic acid could serve tumor prevention by removing photo-damaged cells. PMID:20860736

  7. Color and Light Effects on Learning.

    ERIC Educational Resources Information Center

    Grangaard, Ellen Mannel

    This study examined the effects of color and light on the learning of eleven 6-year-old elementary school students. The students were videotaped to identify off-task behaviors and had their blood pressure measured while in a standard classroom with white walls and cool-white fluorescent lights, as well as in a classroom with light blue walls and…

  8. ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE

    SciTech Connect

    Martino, C.; King, W.; Ketusky, E.

    2012-07-10

    In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate Enhanced Chemical Cleaning (ECC), an alternative to the baseline 8 wt% oxalic acid (OA) chemical cleaning technology for tank sludge heel removal. ECC utilizes a more dilute OA solution (2 wt%) and an oxalate destruction technology using ozonolysis with or without the application of ultraviolet (UV) light. SRNL conducted tests of the ECC process using actual SRS waste material from Tanks 5F and 12H. The previous phase of testing involved testing of all phases of the ECC process (sludge dissolution, OA decomposition, product evaporation, and deposition tank storage) but did not involve the use of UV light in OA decomposition. The new phase of testing documented in this report focused on the use of UV light to assist OA decomposition, but involved only the OA decomposition and deposition tank portions of the process. Compared with the previous testing at analogous conditions without UV light, OA decomposition with the use of UV light generally reduced time required to reach the target of <100 mg/L oxalate. This effect was the most pronounced during the initial part of the decomposition batches, when pH was <4. For the later stages of each OA decomposition batch, the increase in OA decomposition rate with use of the UV light appeared to be minimal. Testing of the deposition tank storage of the ECC product resulted in analogous soluble concentrations regardless of the use or non-use of UV light in the ECC reactor.

  9. Effects of light on brain and behavior

    NASA Technical Reports Server (NTRS)

    Brainard, George C.

    1994-01-01

    It is obvious that light entering the eye permits the sensory capacity of vision. The human species is highly dependent on visual perception of the environment and consequently, the scientific study of vision and visual mechanisms is a centuries old endeavor. Relatively new discoveries are now leading to an expanded understanding of the role of light entering the eye in addition to supporting vision, light has various nonvisual biological effects. Over the past thirty years, animal studies have shown that environmental light is the primary stimulus for regulating circadian rhythms, seasonal cycles, and neuroendocrine responses. As with all photobiological phenomena, the wavelength, intensity, timing and duration of a light stimulus is important in determining its regulatory influence on the circadian and neuroendocrine systems. Initially, the effects of light on rhythms and hormones were observed only in sub-human species. Research over the past decade, however, has confirmed that light entering the eyes of humans is a potent stimulus for controlling physiological rhythms. The aim of this paper is to examine three specific nonvisual responses in humans which are mediated by light entering the eye: light-induced melatonin suppression, light therapy for winter depression, and enhancement of nighttime performance. This will serve as a brief introduction to the growing database which demonstrates how light stimuli can influence physiology, mood and behavior in humans. Such information greatly expands our understanding of the human eye and will ultimately change our use of light in the human environment.

  10. Nanofabrication and applications of subwavelength optical probes: Chemical and biological sensors, light sources and exciton probes

    SciTech Connect

    Tan, W.

    1993-01-01

    The author has developed a new and controllable nanofabrication technique, photo-nanofabrication, based on near-field photo-chemical synthesis and nanometer optical sources. Photo-nanofabrication can produce subwavelength light and exciton probes with or without specific chemical or biological sensitivity. By applying near-field optics, the author has successfully demonstrated a new concept of near-field photochemical synthesis, in which the dimension of a product is solely determined by the size of the light source. The most successful application to date is the development of the smallest fiberoptic chemical sensors. Specifically, a thousandfold miniaturization of an immobilized fiberoptic pH sensor has been achieved, leading to at least a millionfold decrease in necessary sample volume and to at least a hundredfold shorter response time. The sensors have high fluorescence intensity and excellent detection limit. New internal calibration methods have also been developed for accurate pH quantification. The newly developed optical sensors have been used in real time measurements of pH on individual, viable, intact rat conceptuses during the period of organogenesis. The sensors can discriminate pH changes of less than 0.1 pH unit in the physiologic pH range. Static determinations of pH in rat conceptuses of varying gestational ages show decreasing pH with conceptal age. Chemical dynamic alterations in pH of intact rat conceptuses, in response to several variations in their environmental conditions, have been measured. Passive and active subwavelength light sources have been constructed with both micropipettes and fiberoptic tips. They have been used as exciton and light sources and in preliminary probe-to-sample distance regulated, Foerster energy transfer studies as well as in studies of the probe-to-sample interfacial Kasha effect. They were also used in supertip development for near-field scanning optical microscopy and for molecular exciton microscopy.

  11. [Mutagenic effects of ionized plasma light flux].

    PubMed

    Stupin, I V; Dombrovskiĭ, A M; Novokshonov, A I; Belova, L L; Belous, G G

    1990-10-01

    The effect of ion plasma light flux on the genomes of auxotrophic Escherichia coli strain and Drosophilla melanogaster has been examined. Essentially no mutagenic effect was found in doses close to therapeutic ones. PMID:2126213

  12. Tooth bleaching using three laser systems, halogen-light unit, and chemical action agents

    NASA Astrophysics Data System (ADS)

    Dostalova, Tatjana; Jelinkova, Helena; Housova, Devana; Sulc, Jan; Nemec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2004-09-01

    μThe study describes the preclinical experience with laser-activated bleaching agent for discolored teeth. Extracted human upper central incisors were selected, and in the bleaching experiment 35% hydrogen peroxide was used. Three various laser systems and halogen-light unit for activation of the bleaching agent were applied. They were Alexandrite laser (wavelength 750 nm and 375 nm - SHG), Nd:YAG laser (wavelength 1.064 m), and Er:YAG laser (wavelength 2.94 μm). The halogen-light unit was used in a standard regime. The enamel surface was analyzed in the scanning electron microscope. The method of chemical oxidation results in a 2-3 shade change in one treatment. The halogen-light units produced the same effect with shorter time of bleaching process (from 630 s to 300 s). The Alexandrite laser (750 nm) and bleaching agent helped to reach the desired color shade after a shorter time (400 s). Alexandrite laser (375 nm) and Nd:YAG laser had no effect on the longevity of the process of bleaching. Overheating of the chemical bleaching agent was visible after Er:YAG laser activation (195 s). Slight surface modification after bleaching process was detected in SEM.

  13. Visible light Cr(VI) reduction and organic chemical oxidation by TiO2 photocatalysis.

    PubMed

    Sun, Bo; Reddy, Ettireddy P; Smirniotis, Panagiotis G

    2005-08-15

    Here we report the simultaneous Cr(VI) reduction and 4-chlorophenol (4-CP) oxidation in water under visible light (wavelength > 400 nm) using commercial Degussa P25 TiO2. This remarkable observation was attributed to a synergistic effect among TiO2, Cr(VI), and 4-CP. It is well known that TiO2 alone cannot remove either 4-CP or Cr(VI) efficiently under visible light. Moreover, the interaction between Cr(VI) and 4-CP is minimal if not negligible. However, we found that the combination of TiO2, Cr(VI), and 4-CP together can enable efficient Cr(VI) reduction and 4-CP oxidation under visible light. The specific roles of the three ingredients in the synergistic system were studied parametrically. It was found that optimal concentrations of Cr(VI) and TiO2 exist for the Cr(VI) reduction and 4-CP oxidation. Cr(VI) was compared experimentally with other metals such as Cu(ll), Fe(lll), Mn(IV), Ce(IV), and V(V). Among all these metal ions, only Cr(VI) promotes the photocatalytic oxidation of 4-CP. The amount of 4-CP removed was directly related to the initial concentration of Cr(VI). The system was also tested with four other chemicals (aniline, salicylic acid, formic acid, and diethyl phosphoramidate). We found that the same phenomenon occurred for organics containing acid and/or phenolic groups. Cr(VI) was reduced at the same time as the organic chemicals being oxidized during photoreaction under visible light. The synergistic effect was also found with pure anatase TiO2 and rutile TiO2. This study demonstrates a possible economical way for environmental cleanup under visible light. PMID:16173589

  14. Damaging effects of visible light

    NASA Astrophysics Data System (ADS)

    Williams, T. P.; Baker, B. N.

    1982-02-01

    The right eyes of anesthetized, ten week old albino rats are exposed to constant photon fluxes at 6 wavelengths for 6 hours. The left eye of each animal is patched during the exposure and is used as control. Histologic examination of retinal sections disclosed a region in the superior retina which is more damaged than are other areas. Attempting to ascertain an action spectrum by measuring outer nuclear layer (ONL) lost in this sensitive region fails. However, it is shown that when ONL thickness is integrated over the entire retinal sections, a rhodopsin action-spectrum emerges. It is concluded that retinal light damage in the albina rat under these conditions is rhodopsin mediated; and assessment of the extent of damage is best made by some method which integrates over the entire retinal section. The latter methodology is not routinely incorporated into studies of retinal light-damage but probably should be.

  15. Radial spin Hall effect of light

    NASA Astrophysics Data System (ADS)

    Shu, Weixing; Ke, Yougang; Liu, Yachao; Ling, Xiaohui; Luo, Hailu; Yin, Xiaobo

    2016-01-01

    We propose and realize a radial spin Hall effect (SHE) of light by using a dielectric metasurface. The metasurface with radially varying optical axes introduces a Pancharatnam-Berry (PB) geometrical phase to the incident light. The spatial gradient of PB phase accounts for a shift in the momentum space and thus leads the light to split radially into two concentric rays with opposite spin in the position space, which is called a radial SHE. Further experiments verify that the magnitude of the splitting increases with the rotation rate of the optical-axis orientation and the propagation distance, thereby allowing for macroscopic observation of the SHE. We also find that the phase of the incident light influences the profiles of the two split rays, while the polarization determines their intensities. The results provide methods to tune the SHE of light by engineering metasurfaces and modulating the incident light, and this radial SHE may be extrapolated to other physical systems.

  16. Permeability-increasing effects of low-power light

    NASA Astrophysics Data System (ADS)

    Nemtsev, Igor Z.; Koudryavtsev, N. N.

    1996-01-01

    The actions of physico-chemical mechanisms of low power light, applied in medicine are discussed. The investigations were prepared both in experiment on laboratory animals and in emergency-care clinics, where I worked with physicians as the theory-investigator. In this message I propose the theory of permeability increasing effects of low power light. Proton- permeability increasing effects on membranes go to the bioenergetic mechanism of low power light action. Sodium-permeability increasing effects on excitable membranes go to the reflex mechanism of low power light action. We suppose the medical mechanism of laser irradiation effects on the blood to be connected with water-permeability increasing effects because of blood cell membrane depolarization and shaking. We measured the dependence of red blood cell membrane water-permeability coefficient upon the low power light irradiation wavelength in the range 625 - 645 nm. So it was proved that He-Ne laser irradiation with 633 nm wavelength excites dissolved molecular oxygen from the ground triplet state to the singlet state. Fast relaxation of singlet oxygen to triplet state in water medium near membrane with the time 10-6 sec go to the membrane purification mechanism of low power light action.

  17. Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

    PubMed

    Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

    2012-05-01

    In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly. PMID:22407402

  18. Shedding Light on Synergistic Chemical Genetic Connections with Machine Learning.

    PubMed

    Ekins, Sean; Siqueira-Neto, Jair Lage

    2015-12-23

    Machine learning can be used to predict compounds acting synergistically, and this could greatly expand the universe of available potential treatments for diseases that are currently hidden in the dark chemical matter. PMID:27136350

  19. Catalytic effect of light illumination on bioleaching of chalcopyrite.

    PubMed

    Zhou, Shuang; Gan, Min; Zhu, Jianyu; Li, Qian; Jie, Shiqi; Yang, Baojun; Liu, Xueduan

    2015-04-01

    The influence of visible light exposure on chalcopyrite bioleaching was investigated using Acidithiobacillus ferrooxidans. The results indicated, in both shake-flasks and aerated reactors with 8500-lux light, the dissolved Cu was 91.80% and 23.71% higher, respectively, than that in the controls without light. The catalytic effect was found to increase bioleaching to a certain limit, then plateaued as the initial chalcopyrite concentration increased from 2% to 4.5%. Thus a balanced mineral concentration is highly amenable to bioleaching via offering increased available active sites for light adsorption while eschewing mineral aggregation and screening effects. Using semiconducting chalcopyrite, the light facilitated the reduction of Fe(3+) to Fe(2+) as metabolic substrates for A.ferrooxidans, leading to better biomass, lower pH and redox potential, which are conducive to chalcopyrite leaching. The light exposure on iron redox cycling was further confirmed by chemical leaching tests using Fe(3+), which exhibited higher Fe(2+) levels in the light-induced system. PMID:25722073

  20. Chemically driven tunable light emission of charged and neutral excitons in monolayer WS₂.

    PubMed

    Peimyoo, Namphung; Yang, Weihuang; Shang, Jingzhi; Shen, Xiaonan; Wang, Yanlong; Yu, Ting

    2014-11-25

    Monolayer (1L) semiconducting transition metal dichacogenides (TMDs) possess remarkable physical and optical properties, promising for a wide range of applications from nanoelectronics to optoelectronics such as light-emitting and sensing devices. Here we report how the molecular adsorption can modulate the light emission and electrical properties of 1L WS2. The dependences of trion and exciton emission on chemical doping are investigated in 1L WS2 by microphotoluminescence (μPL) measurements, where different responses are observed and simulated theoretically. The total PL is strongly enhanced when electron-withdrawing molecules adsorb on 1L WS2, which is attributed to the increase of the exciton formation due to charge transfer. The electrical transport measurements of a 1L WS2 field effect transistor elucidate the effect of the adsorbates on the conductivity, which give evidence for charge transfer between molecules and 1L WS2. These findings open up many opportunities to manipulate the electrical and optical properties of two-dimensional TMDs, which are particularly important for developing optoelectronic devices for chemical and biochemical sensing applications. PMID:25317839

  1. Chemical communication: a jewel sheds light on signal evolution.

    PubMed

    Lassance, Jean-Marc; Löfstedt, Christer

    2013-05-01

    When others show sexy tails or sing elaborate songs, many animals use the language of chemistry to attract potential mates. A study provides insights into the evolutionary conundrum of how new chemical signals can evolve in an established communication system. PMID:23660353

  2. Controllable light-induced conic structures in silicon nanowire arrays by metal-assisted chemical etching

    NASA Astrophysics Data System (ADS)

    Zhang, Shenli; Wang, Xinwei; Liu, Hong; Shen, Wenzhong

    2014-01-01

    Silicon nanowires (SiNWs) have long been considered a promising material due to their extraordinary electrical and optical properties. As a simple, highly efficient fabrication method for SiNWs, metal-assisted chemical etching (MACE) has been intensively studied over recent years. However, effective control by modulation of simple parameters is still a challenging topic and some key questions still remain in the mechanistic processes. In this work, a novel method to manipulate SiNWs with a light-modulated MACE process has been systematically investigated. Conic structures consisting of inclined and clustered SiNWs can be generated and effectively modified by the incident light while new patterns such as ‘bamboo shoot’ arrays can also be formed under certain conditions. More importantly, detailed study has revealed a new top-down ‘diverting etching’ model of the conic structures in this process, different from the previously proposed ‘bending’ model. As a consequence of this mechanism, preferential lateral mass transport of silver particles occurs. Evidence suggests a relationship of this phenomenon to the inhomogeneous distribution of the light-induced electron-hole pairs beneath the etching front. Study on the morphological change and related mechanism will hopefully open new routes to understand and modulate the formation of SiNWs and other nanostructures.

  3. Retinal Effects Of Blue Light Exposure

    NASA Astrophysics Data System (ADS)

    Ham, William T.; Mueller, Harold A.; Ruffolo, J. J.

    1980-10-01

    Recent research has shown that blue light exposure is an important factor in certain types of retinal injury. The mammalian ocular media transmits the spectral band 400-1400 nm to the retina. The short wavelengths (400-550 nm) produce a photochemical or actinic type of damage, while the longer wavelengths (550-1400 nm) produce thermal damage. Distinction between the two types of retinal damage are discussed briefly and the importance of the blue light effect for solar retinitis and eclipse blindness is emphasized. The significance of blue light retinal injury is summarized for various environmental and occupational exposures.

  4. Effect of Light on Human Circadian Physiology

    PubMed Central

    Duffy, Jeanne F.; Czeisler, Charles A.

    2009-01-01

    Synopsis The circadian system in animals and humans, being near but not exactly 24-hours in cycle length, must be reset on a daily basis in order to remain in synchrony with external environmental time. This process of entrainment is achieved in most mammals through regular exposure to light and darkness. In this chapter, we review the results of studies conducted in our laboratory and others over the past 25 years in which the effects of light on the human circadian timing system were investigated. These studies have revealed, how the timing, intensity, duration, and wavelength of light affect the human biological clock. Our most recent studies also demonstrate that there is much yet to learn about the effects of light on the human circadian timing system. PMID:20161220

  5. Effects of supplementary lighting by natural light for growth of Brassica chinensis

    NASA Astrophysics Data System (ADS)

    Yeh, Shih-Chuan; Lee, Hui-Ping; Kao, Shih-Tse; Lu, Ju-Lin

    2016-04-01

    This paper present a model of cultivated chamber with supplementary natural colour light. We investigate the effects of supplementary natural red light and natural blue light on growth of Brassica chinensis under natural white light illumination. After 4 weeks of supplementary colour light treatment, the experiment results shown that the weight of fresh leaf were not affected by supplementary natural blue light. However, those Brassica chinensis were cultivated in the chambers with supplementary natural red light obtained a significant increasing of fresh weight of leaf under both white light illuminate models. The combination of natural white light with supplementary natural red light illumination will be benefits in growth for cultivation and energy saving.

  6. Adverse Health Effects of Nighttime Lighting

    NASA Astrophysics Data System (ADS)

    Motta, M.

    2012-06-01

    The effects of poor lighting and glare on public safety are well-known, as are the harmful environmental effects on various species and the environment in general. What is less well-known is the potential harmful medical effects of excessive poor nighttime lighting. A significant body of research has been developed over the last few years regarding this problem. One of the most significant effects is the startling increased risk for breast cancer by excessive exposure to nighttime lighting. The mechanism is felt to be by disruption of the circadian rhythm and suppression of melatonin production from the pineal gland. Melatonin has an anticancer effect that is lost when its production is disrupted. I am in the process of developing a monograph that will summarize this important body of research, to be presented and endorsed by the American Medical Association, and its Council of Science and Public health. This paper is a brief overall summary of this little known potential harmful effect of poor and excessive nighttime lighting.

  7. Light Controlled Modulation of Gene Expression by Chemical Optoepigenetic Probes

    PubMed Central

    Reis, Surya A.; Ghosh, Balaram; Hendricks, J. Adam; Szantai-Kis, D. Miklos; Törk, Lisa; Ross, Kenneth N.; Lamb, Justin; Read-Button, Willis; Zheng, Baixue; Wang, Hongtao; Salthouse, Christopher; Haggarty, Stephen J.; Mazitschek, Ralph

    2016-01-01

    Epigenetic gene regulation is a dynamic process orchestrated by chromatin-modifying enzymes. Many of these master regulators exert their function through covalent modification of DNA and histone proteins. Aberrant epigenetic processes have been implicated in the pathophysiology of multiple human diseases. Small-molecule inhibitors have been essential to advancing our understanding of the underlying molecular mechanisms of epigenetic processes. However, the resolution offered by small molecules is often insufficient to manipulate epigenetic processes with high spatio-temporal control. Here, we present a novel and generalizable approach, referred to as ‘Chemo-Optical Modulation of Epigenetically-regulated Transcription’ (COMET), enabling high-resolution, optical control of epigenetic mechanisms based on photochromic inhibitors of human histone deacetylases using visible light. COMET probes may translate into novel therapeutic strategies for diseases where conditional and selective epigenome modulation is required. PMID:26974814

  8. Vertically aligned boron nitride nanosheets: chemical vapor synthesis, ultraviolet light emission, and superhydrophobicity.

    PubMed

    Yu, Jie; Qin, Li; Hao, Yufeng; Kuang, Shengyong; Bai, Xuedong; Chong, Yat-Ming; Zhang, Wenjun; Wang, Enge

    2010-01-26

    Boron nitride (BN) is a promising semiconductor with a wide band gap ( approximately 6 eV). Here, we report the synthesis of vertically aligned BN nanosheets (BNNSs) on silicon substrates by microwave plasma chemical vapor deposition from a gas mixture of BF(3)-N(2)-H(2). The size, shape, thickness, density, and alignment of the BNNSs were well-controlled by appropriately changing the growth conditions. With changing the gas flow rates of BF(3) and H(2) as well as their ratio, the BNNSs evolve from three-dimensional with branches to two-dimensional with smooth surface and their thickness changes from 20 to below 5 nm. The growth of the BNNSs rather than uniform granular films is attributed to the particular chemical properties of the gas system, mainly the strong etching effect of fluorine. The alignment of the BNNSs is possibly induced by the electrical field generated in plasma sheath. Strong UV light emission with a broad band ranging from 200 to 400 nm and superhydrophobicity with contact angles over 150 degrees were obtained for the vertically aligned BNNSs. The present BNNSs possess the properties complementary to carbon nanosheets such as intrinsically semiconducting, high temperature stability, and high chemical inertness and may find applications in ultraviolet nanoelectronics, catalyst supports, electron field emission, and self-cleaning coatings, etc., especially those working at high temperature and in harsh environments. PMID:20047271

  9. Aerosol chemical composition and light scattering during a winter season in Beijing

    NASA Astrophysics Data System (ADS)

    Tao, Jun; Zhang, Leiming; Gao, Jian; Wang, Han; Chai, Faihe; Wang, Shulan

    2015-06-01

    To evaluate PM2.5 contributions to light scattering under different air pollution levels, PM2.5 and its major chemical components, PM10, size-segregated water-soluble ions, and aerosol scattering coefficient (bsp) under dry conditions were measured at an urban site in Beijing in January 2013 when heavy pollution events frequently occurred. Measurements were categorized into three pollution levels including heavy-polluted (Air Quality Index (AQI) ≥ 200), light-polluted (200 > AQI ≥ 100) and clean periods (AQI < 100). The average PM2.5 mass concentration was 248 μg m-3 during the heavy-polluted period, which was 2.4 and 5.6 times of those during the light-polluted (104 μg m-3) and clean (44 μg m-3) periods, respectively. The concentrations of SO42-, NO3- and NH4+ increased much more than those of OC and EC during the heavy-polluted period compared with those during the light-polluted and clean periods. Good correlations between PM2.5 and bsp were found (R2 > 0.95) during the different pollution levels. The mass scattering efficiency (MSE) of PM2.5 was 4.9 m2 g-1 during the heavy-polluted period, which was higher than those during the light-polluted (4.3 m2 g-1) and clean periods (3.6 m2 g-1). To further evaluate the impact of individual chemical components of PM2.5 on light scattering, a multiple linear regression equation of measured bsp against the mass concentration of (NH4)2SO4, NH4NO3, Organic Matter (OM), EC, Fine Soil (FS), Coarse Matter (CM) and Other chemical compounds were performed. (NH4)2SO4, NH4NO3 and OM were the dominant species contributing to bsp under both dry and ambient conditions. OM contributed more to bsp than the sum of (NH4)2SO4 and NH4NO3 did under the dry condition during all the pollution periods and this was also the case under the ambient condition during the light-polluted and clean periods. However, the total contributions of (NH4)2SO4 and NH4NO3 to bsp under the ambient condition was 55%, much more than

  10. Effect of light conditions on the resistance of current-year Fagus Crenata seedlings against fungal pathogens causing damping-off in a natural beech forest: fungus isolation and histological and chemical resistance.

    PubMed

    Ichihara, Yu; Yamaji, Keiko

    2009-09-01

    Forest gap dynamics affects light intensity on the forest floor, which in turn may influence defense and survival of tree seedlings. Current-year Fagus crenata seedlings show high mortality under the canopy caused by damping-off. In contrast, they survive pathogen attacks in gaps. However, defense mechanisms against damping-off have not been fully understood. In order to determine the resistance factors that affect mortality in current-year seedlings, we compared seedling survival and chemical and histological characteristics of the hypocotyls of seedlings from closed-stand and forest-edge plots. Damping-off occurred in the current-year seedlings mainly from the end of June to July; survival rate of the seedlings was higher in the forest-edge plot than in the closed-stand plot. By performing an inoculation test on the seedling hypocotyls, we identified Colletotrichum dematium and Cylindrocarpon sp. as the causative pathogens under low illumination only. In the beginning of July, only seedling hypocotyls from the forest-edge plot exhibited periderm formation. From mid-June to July, seedling hypocotyls from the forest-edge plot accumulated approximately twice the amount of total phenols as those accumulated by seedling hypocotyls from the closed-stand plot. The ethyl acetate phase of methanol extracts of hypocotyls showed antifungal activity. We conclude that seedlings from the forest-edge plot may resist pathogenic attack via periderm formation and increased phenol synthesis. Plant defense mechanisms that are controlled by light intensity may be important for promoting seedling regeneration in forest gap dynamics. PMID:19774414

  11. Light induced chemical vapour deposition of titanium oxide thin films at room temperature

    NASA Astrophysics Data System (ADS)

    Halary, E.; Benvenuti, G.; Wagner, F.; Hoffmann, P.

    2000-02-01

    High resolution patterned deposition of titania is achieved by light induced chemical vapour deposition (LICVD), by imaging a mask onto a glass substrate. A long pulse XeCl Excimer laser (308 nm) provides, by perpendicular irradiation, the energy to convert titanium tetraisopropoxide (TTIP) vapour into titanium dioxide films, in an oxygen atmosphere, on unheated glass substrates. The amorphous titania deposits contain about 6% carbon contamination according to X-ray photoelectron spectroscopy (XPS) measurements. The deposition rate increases with increasing laser fluence until a maximum value is reached, then remains constant over a wide range, and finally decreases with further fluence increase due to titania ablation or thermal effects. The film thickness increases linearly with the number of pulses after a nucleation period. The strong influence of the laser pulse repetition rate on the growth rate and the thickness profile are reported.

  12. Chemically Induced Changes to Membrane Permeability in Living Cells Probed with Nonlinear Light Scattering.

    PubMed

    Wilhelm, Michael J; Sharifian Gh, Mohammad; Dai, Hai-Lung

    2015-07-28

    Second-harmonic light scattering (SHS) permits characterization of membrane-specific molecular transport in living cells. Herein, we demonstrate the use of time-resolved SHS for quantifying chemically induced enhancements in membrane permeability. As proof of concept, we examine the enhanced permeability of the cytoplasmic membrane in living Escherichia coli following addition of extracellular adenosine triphosphate (ATPe). The transport rate of the hydrophobic cation, malachite green, increases nearly an order of magnitude following addition of 0.1 mM ATPe. The absence of an ATPe-enhanced permeability in liposomes strongly suggests the induced effect is protein-mediated. The utility of SHS for elucidating the mechanism of action of antimicrobials is discussed. PMID:26122620

  13. Electromagnetic effects on the light hadron spectrum

    NASA Astrophysics Data System (ADS)

    Basak, S.; Bazavov, A.; Bernard, C.; DeTar, C.; Freeland, E.; Foley, J.; Gottlieb, Steven; Heller, U. M.; Komijani, J.; Laiho, J.; Levkova, L.; Li, R.; Osborn, J.; Sugar, R. L.; Torok, A.; Toussaint, D.; Van de Water, R. S.; Zhou, R.; Collaboration MILC

    2015-09-01

    For some time, the MILC Collaboration has been studying electromagnetic effects on light mesons. These calculations use fully dynamical QCD, but only quenched photons, which suffices to NLO in χPT. That is, the sea quarks are electrically neutral, while the valence quarks carry charge. For the photons we use the non-compact formalism. We have new results with lattice spacing as small as 0.045 fm and a large range of volumes. We consider how well chiral perturbation theory describes these results and the implications for light quark masses.

  14. Electromagnetic effects on the light hadron spectrum

    DOE PAGESBeta

    Basak, S.; Bazavov, A.; Bernard, C.; DeTar, C.; Freeland, E.; Foley, J.; Gottlieb, Steven; Heller, U. M.; Komijani, J.; Laiho, J.; et al

    2015-01-01

    Calculations studying electromagnetic effects on light mesons are reported. The calculations use fully dynamical QCD, but only quenched photons, which suffices to NLO in χPT; that is, the sea quarks are electrically neutral, while the valence quarks carry charge. The non-compact formalism is used for photons. New results are obtained with lattice spacing as small as 0.045 fm and a large range of volumes. The success of chiral perturbation theory in describing these results and the implications for light quark masses are considered.

  15. Zeeman effect induced by intense laser light.

    PubMed

    Stambulchik, E; Maron, Y

    2014-08-22

    We analyze spectral line shapes of hydrogenlike species subjected to fields of electromagnetic waves. It is shown that the magnetic component of an electromagnetic wave may significantly influence the spectra. In particular, the Zeeman effect induced by a visible or infrared light can be experimentally observed using present-day powerful lasers. In addition, the effect may be used for diagnostics of focused beam intensities achieved at existing and newly built laser facilities. PMID:25192094

  16. Thyroid effects of endocrine disrupting chemicals.

    PubMed

    Boas, Malene; Feldt-Rasmussen, Ulla; Main, Katharina M

    2012-05-22

    In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert thyroid effects through a variety of mechanisms of action, and some animal experiments and in vitro studies have focused on elucidating the mode of action of specific chemical compounds. Long-term human studies on effects of environmental chemicals on thyroid related outcomes such as growth and development are still lacking. The human exposure scenario with life long exposure to a vast mixture of chemicals in low doses and the large physiological variation in thyroid hormone levels between individuals render human studies very difficult. However, there is now reasonably firm evidence that PCBs have thyroid-disrupting effects, and there is emerging evidence that also phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals may have thyroid disrupting properties. PMID:21939731

  17. Building Twilight "Light Sensors" to Study the Effects of Light Pollution on Fireflies

    ERIC Educational Resources Information Center

    Thancharoen, Anchana; Branham, Marc A.; Lloyd, James E.

    2008-01-01

    Light pollution negatively affects many nocturnal organisms. We outline two experiments that can be conducted by students to examine the effects of light pollution on firefly behavior. Inexpensive electronic light sensors, which are easy to construct and calibrate, are used to sample light levels along transects in spaces where fireflies are…

  18. Studying the Effect of Light Quality on the Size of the Photosystem II Light Harvesting Complex

    ERIC Educational Resources Information Center

    Muhoz, Romualdo; Quiles, Maria J.

    2003-01-01

    In this article the effect of light quality on the size of the photosystem II (PSII) light harvesting complex (LHCII) is studied by measuring the chlorophyll fluorescence emitted by leaf sections of oat ("Avena sativa," var. Prevision) plants previously treated with either white light or with light filtered through blue, green, red or farred…

  19. Light-triggered chemical amplification to accelerate degradation and release from polymeric particles.

    PubMed

    Olejniczak, Jason; Nguyen Huu, Viet Anh; Lux, Jacques; Grossman, Madeleine; He, Sha; Almutairi, Adah

    2015-12-11

    We describe a means of chemical amplification to accelerate triggered degradation of a polymer and particles composed thereof. We designed a light-degradable copolymer containing carboxylic acids masked by photolabile groups and ketals. Photolysis allows the unmasked acidic groups in the polymer backbone to accelerate ketal hydrolysis even at neutral pH. PMID:26445896

  20. Light-emitting channelrhodopsins for combined optogenetic and chemical-genetic control of neurons.

    PubMed

    Berglund, Ken; Birkner, Elisabeth; Augustine, George J; Hochgeschwender, Ute

    2013-01-01

    Manipulation of neuronal activity through genetically targeted actuator molecules is a powerful approach for studying information flow in the brain. In these approaches the genetically targeted component, a receptor or a channel, is activated either by a small molecule (chemical genetics) or by light from a physical source (optogenetics). We developed a hybrid technology that allows control of the same neurons by both optogenetic and chemical genetic means. The approach is based on engineered chimeric fusions of a light-generating protein (luciferase) to a light-activated ion channel (channelrhodopsin). Ionic currents then can be activated by bioluminescence upon activation of luciferase by its substrate, coelenterazine (CTZ), as well as by external light. In cell lines, expression of the fusion of Gaussia luciferase to Channelrhodopsin-2 yielded photocurrents in response to CTZ. Larger photocurrents were produced by fusing the luciferase to Volvox Channelrhodopsin-1. This version allowed chemical modulation of neuronal activity when expressed in cultured neurons: CTZ treatment shifted neuronal responses to injected currents and sensitized neurons to fire action potentials in response to subthreshold synaptic inputs. These luminescent channelrhodopsins--or luminopsins--preserve the advantages of light-activated ion channels, while extending their capabilities. Our proof-of-principle results suggest that this novel class of tools can be improved and extended in numerous ways. PMID:23544095

  1. Lethal effects of short-wavelength visible light on insects

    NASA Astrophysics Data System (ADS)

    Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

    2014-12-01

    We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

  2. All-in-one light-tunable borated phosphors with chemical and luminescence dynamical control resolution.

    PubMed

    Lin, Chun Che; Liu, Yun-Ping; Xiao, Zhi Ren; Wang, Yin-Kuo; Cheng, Bing-Ming; Liu, Ru-Shi

    2014-06-25

    Single-composition white-emitting phosphors with superior intrinsic properties upon excitation by ultraviolet light-emitting diodes are important constituents of next-generation light sources. Borate-based phosphors, such as NaSrBO3:Ce(3+) and NaCaBO3:Ce(3+), have stronger absorptions in the near-ultraviolet region as well as better chemical/physical stability than oxides. Energy transfer effects from sensitizer to activator caused by rare-earth ions are mainly found in the obtained photoluminescence spectra and lifetime. The interactive mechanisms of multiple dopants are ambiguous in most cases. We adjust the doping concentration in NaSrBO3:RE (RE = Ce(3+), Tb(3+), Mn(2+)) to study the energy transfer effects of Ce(3+) to Tb(3+) and Mn(2+) by comparing the experimental data and theoretical calculation. The vacuum-ultraviolet experimental determination of the electronic energy levels for Ce(3+) and Tb(3+) in the borate host regarding the 4f-5d and 4f-4f configurations are described. Evaluation of the Ce(3+)/Mn(2+) intensity ratios as a function of Mn(2+) concentration is based on the analysis of the luminescence dynamical process and fluorescence lifetime measurements. The results closely agree with those directly obtained from the emission spectra. Density functional calculations are performed using the generalized gradient approximation plus an on-site Coulombic interaction correction scheme to investigate the forbidden mechanism of interatomic energy transfer between the NaSrBO3:Ce(3+) and NaSrBO3:Eu(2+) systems. Results indicate that the NaSrBO3:Ce(3+), Tb(3+), and Mn(2+) phosphors can be used as a novel white-emitting component of UV radiation-excited devices. PMID:24844411

  3. Preparation and Effect of Lighting on Structures and Properties of GSH Capped ZnSe QDs.

    PubMed

    Ding, Ling; Peng, Zeze; Zhou, Peijiang; Cheng, Gary J; Nian, Qiong; Lin, Dong; Zhou, Jinhui; Liang, Yuhe

    2015-11-01

    L-glutathione (GSH) capped ZnSe quantum dots (QDs) were prepared by microwave-assisted aqueous synthesis. Then, the resulting QDs were illuminated under dark, ultraviolet light and incandescent light, respectively. Thereby effect of lighting on the structures and properties of QDs were studied systematically. It was revealed that particle size and element content of QDs took a sharp change after irradiation, while the crystal structure maintains nearly unaffected. Comparing to the ZnSe QDs under dark condition, counterparts irradiated by UV light possessed outstanding sphericity, size distribution and dispersion. And the content of sulfur (S) in ZnSe QDs irradiated by UV light was much higher relatively. The effect of lighting on vibration peaks of O-H was considerable. However, this effect was observed to be weak on other chemical bonds. The possible explanation ascribes to photo-chemical interactions can occur between S-H and O-H bonds on the surface of GSH ligand. The lighting induced GSH to occur photocatalytic oxidation on the surface of ZnSe QDs, which improved the optical properties of QDs. The effects of lighting rely on irradiation types, the sequence is UV light, incandescent light and dark from high to low. PMID:26377128

  4. Effect of wettability on light oil steamflooding

    SciTech Connect

    Olsen, D.K.

    1991-12-01

    This report summarizes NIPER's research on four interrelated topics for Light Oil Steamflooding. Four interrelated topics are described: The methodology for measuring capillary pressure and wettability at elevated temperature, the use of silylating agents to convert water-wet Berea sandstones or unconsolidated quartz sands to oil-wetted surfaces, the evaluation of the thermal hydrolytic stability of these oil-wet surfaces for possible use in laboratory studies using steam and hot water to recover oil, and the effect of porous media of different wettabilities on oil recovery where the porous media is first waterflooded and then steamflooded.

  5. Effect of wettability on light oil steamflooding

    SciTech Connect

    Olsen, D.K.

    1991-12-01

    This report summarizes NIPER`s research on four interrelated topics for Light Oil Steamflooding. Four interrelated topics are described: The methodology for measuring capillary pressure and wettability at elevated temperature, the use of silylating agents to convert water-wet Berea sandstones or unconsolidated quartz sands to oil-wetted surfaces, the evaluation of the thermal hydrolytic stability of these oil-wet surfaces for possible use in laboratory studies using steam and hot water to recover oil, and the effect of porous media of different wettabilities on oil recovery where the porous media is first waterflooded and then steamflooded.

  6. Detailed chemical abundances of extragalactic globular clusters using high resolution, integrated light spectra

    NASA Astrophysics Data System (ADS)

    Colucci, Janet E.

    Globular clusters (GCs) are luminous, observationally accessible objects that are good tracers of the total star formation and evolutionary history of galaxies. We present the first detailed chemical abundances for GCs in M31 using a new abundance analysis technique designed for high resolution, integrated light (IL) spectra of GCs. This technique has recently been developed using a training set of old GCS in the Milky Way (MW), and makes possible detailed chemical evolution studies of distant galaxies, where high resolution abundance analysis of individual stars are not obtainable. For the 5 M31 GCs presented here, we measure abundances of 14 elements: Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, and Ba. We find the M31 GCs have ages (>10 Gyr) and chemical properties similar to MW GCs, including an enhancement in the alpha-elements Ca, Ti and Si of [alpha/Fe]˜ +0.4. In this thesis, we also further develop this IL abundance analysis method to include GCs of ages 10 Myr--12 Gyrs using GCs in the Large Magellanic Cloud (LMC), which contains the necessary sample of clusters over this wide age range. This work demonstrates for the first time that this IL abundance analysis method can be used on clusters of all ages, and that ages can be constrained to within 1--2 Gyr for clusters with ages of ˜2 Gyr and within a few 100 Myr for clusters with ages <1 Gyr. We find that we can measure [Fe/H] in clusters with ages <12 Gyrs with similar or only slightly larger uncertainties (0.1--0.25 dex) than those obtained for old GCs; the slightly larger uncertainties are due to the rapid evolution in stellar populations at these ages. Using the LMC clusters, we also investigate the effects of statistical fluctuations in the theoretical cluster stellar populations used in our analysis. We also develop strategies to allow for statistical variations in these stellar populations, and find that the stability of the Fe line abundance solution can provide tight constraints on the

  7. Effective Chemical Inactivation of Ebola Virus

    PubMed Central

    Haddock, Elaine; Feldmann, Friederike

    2016-01-01

    Reliable inactivation of specimens before removal from high-level biocontainment is crucial for safe operation. To evaluate efficacy of methods of chemical inactivation, we compared in vitro and in vivo approaches using Ebola virus as a surrogate pathogen. Consequently, we have established parameters and protocols leading to reliable and effective inactivation. PMID:27070504

  8. Effective Chemical Inactivation of Ebola Virus.

    PubMed

    Haddock, Elaine; Feldmann, Friederike; Feldmann, Heinz

    2016-07-01

    Reliable inactivation of specimens before removal from high-level biocontainment is crucial for safe operation. To evaluate efficacy of methods of chemical inactivation, we compared in vitro and in vivo approaches using Ebola virus as a surrogate pathogen. Consequently, we have established parameters and protocols leading to reliable and effective inactivation. PMID:27070504

  9. Changes in the chemical components of light crude oil during simulated short term weathering

    NASA Astrophysics Data System (ADS)

    Ma, Qimin; Luo, Xia; Yu, Zhigang

    2007-07-01

    To unambiguously identify spilled oils and to link them to the known sources are extremely important in settling questions of environmental impact and legal liability. The fate and behavior of spilled oils in the environment depend on a number of physicochemical and biological factors. This paper presents the results regarding changes in chemical composition of light crude oil during simulated short-term weathering based on natural environmental conditions. The results show that the saturated hydrocarbons of the light crude oil mainly distribute between n-C8 and n-C23 and the most abundant n-alkanes are found in the n-C10 to n-C16. The main chemical components of the light crude oil are n-alkanes and isoprenoids. The aromatic compounds are subordinate chemical components. Under the conditions of the weathering simulation experiment, n-alkanes less than n-C12, toluene and 1,3-dimethyl benzene are lost after 1 d weathering, the n-C13, n-C14, naphthalene and 2-methyl-naphthalene are lost on the fifth day of weathering, and n-C15 alkane components show certain weatherproof capability. The ratios n-C17/pristane and n-C18/phytane are unaltered and can be used to identify the source of the light crude oil during the first 8 d of weathering. After 21 d, the ratio pristine/phytane can not provide much information on the source of the spilled light crude oil. Triterpanes (m/z 191) as biomarker compounds of light crude oil are more valuable.

  10. Fabrication of broadband antireflective black metal surfaces with ultra-light-trapping structures by picosecond laser texturing and chemical fluorination

    NASA Astrophysics Data System (ADS)

    Zheng, Buxiang; Wang, Wenjun; Jiang, Gedong; Mei, Xuesong

    2016-06-01

    A hybrid method consisting of ultrafast laser-assisted texturing and chemical fluorination treatment was applied for efficiently enhancing the surface broadband antireflection to fabricate black titanium alloy surface with ultra-light-trapping micro-nanostructure. Based on the theoretical analysis of surface antireflective principle of micro-nanostructures and fluoride film, the ultra-light-trapping micro-nanostructures have been processed using a picosecond pulsed ultrafast laser on titanium alloy surfaces. Then fluorination treatment has been performed by using fluoroalkyl silane solution. According to X-ray diffraction phase analysis of the surface compositions and measurement of the surface reflectance using spectrophotometer, the broadband antireflective properties of titanium alloy surface with micro-nano structural characteristics were investigated before and after fluorination treatment. The results show that the surface morphology of micro-nanostructures processed by picosecond laser has significant effects on the antireflection of light waves to reduce the surface reflectance, which can be further reduced using chemical fluorination treatment. The high antireflection of over 98 % in a broad spectral range from ultraviolet to infrared on the surface of metal material has been achieved for the surface structures, and the broadband antireflective black metal surfaces with an extremely low reflectance of ultra-light-trapping structures have been obtained in the wavelength range from ultraviolet-visible to near-infrared, middle-wave infrared. The average reflectance of microgroove groups structured surface reaches as low as 2.43 % over a broad wavelength range from 200 to 2600 nm. It indicates that the hybrid method comprising of picosecond laser texturing and chemical fluorination can effectively induce the broadband antireflective black metal surface. This method has a potential application for fabricating antireflective surface used to improve the

  11. Damaging effects of visible light. Comprehensive progress report

    SciTech Connect

    1981-01-01

    Research progress is reported on studies of retinal light damage. A myriad of variables effect the production of light damage. These include age, prior light history, body temperature, vitamin A status, intensity, wavelength and duration of light. The intensity-duration function and the age function have been studied in detail in rats. Studies have been begun on the wavelength variable. (ACR)

  12. The difference of the PDT's effects between interstitial lighting and continuous lighting in low oxygen density

    NASA Astrophysics Data System (ADS)

    Yang, Jiumin; Li, Yingxin; Liu, Tiegen; Xu, Tao

    2008-02-01

    Tumor oxygen depletion plays an important role in the process of Photodynamic Therapy (PDT). The paper focuses on the improvement of the lighting mode to carry out this cancer therapy more effectively in low oxygen content. The effect of interstitial lighting was compared with that of continuous lighting in different oxygen density measured with a homemade device in PDT. 90 mice were divided into 3 groups: the contrast group, the continuous lighting group and the interstitial lighting group. The initial oxygen content was measured with a homemade device before the treatment. To examine the different effects, both the interstitial lighting and the continuous lighting have the same fluent rates (30mW/cm2, 32.4J/ cm2). The continuous lighting lasted 18 minutes while the interstitial lighting lasted 36 minutes with 1 second's idle time and 1 second's effective time of each pulse. The result shows that the volume of tumor doubling duration in interstitial lighting group is longer in the condition of low initial oxygen content. Thus with low initial oxygen content, the interstitial lighting is more effective than the continuous lighting during PDT.

  13. A SIGNATURE OF CHEMICAL SEPARATION IN THE COOLING LIGHT CURVES OF TRANSIENTLY ACCRETING NEUTRON STARS

    SciTech Connect

    Medin, Zach; Cumming, Andrew E-mail: cumming@physics.mcgill.ca

    2014-03-01

    We show that convection driven by chemical separation can significantly affect the cooling light curves of accreting neutron stars after they go into quiescence. We calculate the thermal relaxation of the neutron star ocean and crust including the thermal and compositional fluxes due to convection. After the inward propagating cooling wave reaches the base of the neutron star ocean, the ocean begins to freeze, driving chemical separation. The resulting convection transports heat inward, giving much faster cooling of the surface layers than found assuming the ocean cools passively. The light curves including convection show a rapid drop in temperature weeks after outburst. Identifying this signature in observed cooling curves would constrain the temperature and composition of the ocean as well as offer a real time probe of the freezing of a classical multicomponent plasma.

  14. Chemical Pressure Effects in Layered Manganites

    NASA Astrophysics Data System (ADS)

    Moritomo, Yutaka; Maruyama, Yousuke; Nakamura, Arao

    1998-03-01

    Lattice effects on the magnetic and transport properties have been investigated for layered-type doped mangaites. The insulator-to-metal transition temperature for La_1.2Sr_1.8Mn_2O7 (T_C=130 K) is significantly suppressed with chemical substitution of the trivalent La^3+ ions to smaller Nd^3+ (or Sm^3+) ions(Y. Moritomo et al), Phys. Rev. B56(1997)R7057. Similarly, the charge-ordering temperature for La_0.5Sr_1.5MnO4 (T_CO=230 K) is suppresses with chemical substitution(Y. Moritomo et al), Phys. Rev. B56, in press. Systematic x-ray as well as neutron diffraction measurements have revealed that above chemical pressure enhances the static Jahn-Teller distortion of the MnO6 octahedra in both the system. We will explain the suppressions of TC and T_CO in terms of the increasing d_3z^2-r^2 character in the occupied eg state. Our observation indicates that the chemical pressure effects are qualitatively different between the cubic and layered manganites systems. The authors are grateful to K. Ohoyama and M. Ohashi for their help in neutron diffraction measurements, and to S. Mori for his help in electron diffraction measurements. This work was supported by a Grant-In-Aid for Scientific Research from the Ministry of Education, Science, Sport and Culture and from PRESTO, Japan Scienece and Technology Corporation (JST), Japan.

  15. Spectral and temperature characteristics of light transmission in solutions of chemical indicators

    NASA Astrophysics Data System (ADS)

    Gavrichev, V. D.; Dmitriev, A. L.; Karacharov, G.; Nagibin, Yu. T.

    2015-12-01

    Spectral and temperature characteristics of light transmission in water solutions of chemical indicators— bromophenol blue, bromothymol blue, and cresol red—were measured in the wavelength range of 500-750 nm and the temperature range from 20 to 90°C. It was demonstrated that these solutions can be applied in optical fiber thermometers with continuous reading which are not affected by strong external electromagnetic fields.

  16. Chemically unassisted phototherapy: dose effects via real-time optical monitoring of cancer cells

    NASA Astrophysics Data System (ADS)

    Landry, Sylvie; Keeler, Werden

    2010-03-01

    Ultraviolet (UV) light and short wavelength visible (VIS) light have been used to kill pathogens for many years. Although the adverse effects of UV radiation on living cells have been extensively studied using biochemical and biomolecular techniques, most of the light therapies used for medical treatment are chemically assisted (i.e., photodynamic therapy). However, the use of light alone could prove both cost and therapeutically effective as an alternative treatment modality for localized diseases. In this study, real-time oblique incidence reflection (OIR) microscopy and image analysis were used to visualize and quantify the effects of chemically unassisted light therapy on untagged live cancer cells in vitro. The incident radiation fluence (in mJ/cm^2) required to induce cell death was determined for selected quasi-monochromatic UV to VIS wavelengths ranging from 275nm to 460nm. A predictive mathematical equation quantifying the lethal fluence as a function of wavelength will be discussed.

  17. Spatial resolution effect of light coupling structures

    NASA Astrophysics Data System (ADS)

    Li, Juntao; Li, Kezheng; Schuster, Christian; Su, Rongbin; Wang, Xuehua; Borges, Ben-Hur V.; Krauss, Thomas F.; Martins, Emiliano R.

    2015-12-01

    The coupling of light between free space and thin film semiconductors is an essential requirement of modern optoelectronic technology. For monochromatic and single mode devices, high performance grating couplers have been developed that are well understood. For broadband and multimode devices, however, more complex structures, here referred to as “coupling surfaces”, are required, which are often difficult to realise technologically. We identify general design rules based on the Fourier properties of the coupling surface and show how they can be used to determine the spatial resolution required for the coupler’s fabrication. To our knowledge, this question has not been previously addressed, but it is important for the understanding of diffractive nanostructures and their technological realisation. We exemplify our insights with solar cells and UV photodetectors, where high-performance nanostructures that can be realised cost-effectively are essential.

  18. Effects of light on scintillating fibers

    NASA Astrophysics Data System (ADS)

    Chung, Manho; Margulies, Seymour

    1993-10-01

    Tracking detectors based on scintillating-fiber technology are being developed for the Solenoidal Detector Collaboration at the Superconducting Super Collider and for the D0 collaboration at Fermilab. An important part of the work is to insure that the fibers will not be damaged by environmental conditions in the course of detector construction. This paper presents preliminary results of the effects of ambient fluorescent light on scintillating fibers containing 3-hydroxyflavone (3HF) waveshifter. Six fiber types having 3HF concentrations between 100 ppm and 6000 ppm were studied; both single-clad fibers from Bicron and Kuraray and a new Kuraray multiclad fiber were included. A blue fiber containing no 3HF was used to provide a comparison.

  19. Spatial resolution effect of light coupling structures

    PubMed Central

    Li, Juntao; Li, Kezheng; Schuster, Christian; Su, Rongbin; Wang, Xuehua; Borges, Ben-Hur V.; Krauss, Thomas F.; Martins, Emiliano R.

    2015-01-01

    The coupling of light between free space and thin film semiconductors is an essential requirement of modern optoelectronic technology. For monochromatic and single mode devices, high performance grating couplers have been developed that are well understood. For broadband and multimode devices, however, more complex structures, here referred to as “coupling surfaces”, are required, which are often difficult to realise technologically. We identify general design rules based on the Fourier properties of the coupling surface and show how they can be used to determine the spatial resolution required for the coupler’s fabrication. To our knowledge, this question has not been previously addressed, but it is important for the understanding of diffractive nanostructures and their technological realisation. We exemplify our insights with solar cells and UV photodetectors, where high-performance nanostructures that can be realised cost-effectively are essential. PMID:26678574

  20. Chemical amplification of magnetic field effects relevant to avian magnetoreception

    NASA Astrophysics Data System (ADS)

    Kattnig, Daniel R.; Evans, Emrys W.; Déjean, Victoire; Dodson, Charlotte A.; Wallace, Mark I.; MacKenzie, Stuart R.; Timmel, Christiane R.; Hore, P. J.

    2016-04-01

    Magnetic fields as weak as the Earth's can change the yields of radical pair reactions even though the energies involved are orders of magnitude smaller than the thermal energy, kBT, at room temperature. Proposed as the source of the light-dependent magnetic compass in migratory birds, the radical pair mechanism is thought to operate in cryptochrome flavoproteins in the retina. Here we demonstrate that the primary magnetic field effect on flavin photoreactions can be amplified chemically by slow radical termination reactions under conditions of continuous photoexcitation. The nature and origin of the amplification are revealed by studies of the intermolecular flavin-tryptophan and flavin-ascorbic acid photocycles and the closely related intramolecular flavin-tryptophan radical pair in cryptochrome. Amplification factors of up to 5.6 were observed for magnetic fields weaker than 1 mT. Substantial chemical amplification could have a significant impact on the viability of a cryptochrome-based magnetic compass sensor.

  1. Chemical aspects of pellet-cladding interaction in light water reactor fuel elements

    SciTech Connect

    Olander, D.R.

    1982-01-01

    In contrast to the extensive literature on the mechanical aspects of pellet-cladding interaction (PCI) in light water reactor fuel elements, the chemical features of this phenomenon are so poorly understood that there is still disagreement concerning the chemical agent responsible. Since the earliest work by Rosenbaum, Davies and Pon, laboratory and in-reactor experiments designed to elucidate the mechanism of PCI fuel rod failures have concentrated almost exclusively on iodine. The assumption that this is the reponsible chemical agent is contained in models of PCI which have been constructed for incorporation into fuel performance codes. The evidence implicating iodine is circumstantial, being based primarily upon the volatility and significant fission yield of this element and on the microstructural similarity of the failed Zircaloy specimens exposed to iodine in laboratory stress corrosion cracking (SCC) tests to cladding failures by PCI.

  2. Kinetic Effects of Laser Light on Rubidium

    NASA Astrophysics Data System (ADS)

    Xie, Chuan

    1995-01-01

    In part one of this dissertation, a derivation of the semi-classical kinetic theory of laser-atom interaction for a general multilevel atom is presented, followed by a complete algorithm for the calculation of the force and diffusion as functions of atomic velocity. In contrast to previous numerical methods, the excited states of the atom are not eliminated in this algorithm. Velocity dependent Raman resonances (Ramanons) in a three level Lambda-system are calculated using the general algorithm and physical origin of these resonances is discussed. In part two of the thesis, two novel experiments on the kinetic effects of laser light on rubidium atoms are reported. Transient effects in laser cooling are reported and studied in detail. A semiclassical simulation based on the physical interpretation of these effects agrees well with both the experimental data and results from the quantum calculations, indicating a good understanding of the phenomena. Results of systematic study of a new cooling scheme using a standing wave laser field of two frequencies are presented. In this scheme, sub-Doppler cooling is achieved without either a polarization gradient or a B-field. In addition to cooling and heating, deflection of atoms by a rectified dipole force is observed for certain laser parameters.

  3. Chemical and thermodynamic control of the surface of semiconductor nanocrystals for designer white light emitters.

    PubMed

    Krause, Michael M; Mooney, Jonathan; Kambhampati, Patanjali

    2013-07-23

    Small CdSe semiconductor nanocrystals with diameters below 2 nm are thought to emit white light due to random surface defects which result in a broad distribution of midgap emitting states, thereby preventing rational design of small nanocrystal white light emitters. We perform temperature dependent photoluminescence experiments before and after ligand exchange and electron transfer simulations to reveal a very simple microscopic picture of the origin of the white light. These experiments and simulations reveal that these small nanocrystals can be physically modeled in precisely the same way as normal-sized semiconductor nanocrystals; differences in their emission spectra arise from their surface thermodynamics. The white light emission is thus a consequence of the thermodynamic relationship between a core excitonic state and an optically bright surface state with good quantum yield. By virtue of this understanding of the surface and the manner in which it is coupled to the core excitonic states of these nanocrystals, we show both chemical and thermodynamic control of the photoluminescence spectra. We find that using both temperature and appropriate choice in ligands, one can rationally control the spectra so as to engineer the surface to target color rendering coordinates for displays and white light emitters. PMID:23802709

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

    PubMed Central

    Niwa, Haruki; Inouye, Satoshi; Hirano, Takashi; Matsuno, Tatsuki; Kojima, Satoshi; Kubota, Masayuki; Ohashi, Mamoru; Tsuji, Frederick I.

    1996-01-01

    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 (λmax = 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. PMID:8942983

  5. 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.

  6. Effect of light sources and light intensity on growth performance and behaviour of female turkeys.

    PubMed

    Denbow, D M; Leighton, A T; Hulet, R M

    1990-09-01

    1. The effect of different light sources (incandescent, sodium vapour, daylight fluorescent and warm fluorescent) and light intensities (10.8 and 86.1 lux) on growth performance and behaviour of female turkeys was investigated in two experiments conducted at different times of the year. 2. Although light source influenced body weight and efficiency of food utilisation, there was no consistent effect between experiments in favour of any particular source. 3. Light intensity had no effect on body weight, efficiency of food utilisation or behaviour. PMID:2245342

  7. Light-induced nitrous acid (HONO) production from NO2 heterogeneous reactions on household chemicals

    NASA Astrophysics Data System (ADS)

    Gómez Alvarez, Elena; Sörgel, Matthias; Gligorovski, Sasho; Bassil, Sabina; Bartolomei, Vincent; Coulomb, Bruno; Zetzsch, Cornelius; Wortham, Henri

    2014-10-01

    Nitrous acid (HONO) can be generated in various indoor environments directly during combustion processes or indirectly via heterogeneous NO2 reactions with water adsorbed layers on diverse surfaces. Indoors not only the concentrations of NO2 are higher but the surface to volume (S/V) ratios are larger and therefore the potential of HONO production is significantly elevated compared to outdoors. It has been claimed that the UV solar light is largely attenuated indoors. Here, we show that solar light (λ > 340 nm) penetrates indoors and can influence the heterogeneous reactions of gas-phase NO2 with various household surfaces. The NO2 to HONO conversion mediated by light on surfaces covered with domestic chemicals has been determined at atmospherically relevant conditions i.e. 50 ppb NO2 and 50% RH. The formation rates of HONO were enhanced in presence of light for all the studied surfaces and are determined in the following order: 1.3·109 molecules cm-2 s-1 for borosilicate glass, 1.7·109 molecules cm-2 s-1 for bathroom cleaner, 1.0·1010 molecules cm-2 s-1 on alkaline detergent (floor cleaner), 1.3·1010 molecules cm-2 s-1 for white wall paint and 2.7·1010 molecules cm-2 s-1 for lacquer. These results highlight the potential of household chemicals, used for cleaning purposes to generate HONO indoors through light-enhanced NO2 heterogeneous reactions. The results obtained have been applied to predict the timely evolution of HONO in a real indoor environment using a dynamic mass balance model. A steady state mixing ratio of HONO has been estimated at 1.6 ppb assuming a contribution from glass, paint and lacquer and considering the photolysis of HONO as the most important loss process.

  8. Geometric spin Hall effect of light in tightly focused polarization-tailored light beams

    NASA Astrophysics Data System (ADS)

    Neugebauer, Martin; Banzer, Peter; Bauer, Thomas; Orlov, Sergej; Lindlein, Norbert; Aiello, Andrea; Leuchs, Gerd

    2014-01-01

    Recently, it was shown that a nonzero transverse angular momentum manifests itself in a polarization-dependent intensity shift of the barycenter of a paraxial light beam [Aiello et al., Phys. Rev. Lett. 103, 100401 (2009), 10.1103/PhysRevLett.103.100401]. The underlying effect is phenomenologically similar to the spin Hall effect of light but does not depend on the specific light-matter interaction and can be interpreted as a purely geometric effect. Thus, it was named the geometric spin Hall effect of light. Here, we experimentally investigate the appearance of this effect in tightly focused vector beams. We use an experimental nanoprobing technique in combination with a reconstruction algorithm to verify the relative shifts of the components of the electric energy density and the shift of the intensity in the focal plane. By that, we experimentally demonstrate the geometric spin Hall effect of light in a highly nonparaxial beam.

  9. Lighting up stars in chemical evolution models: the CMD of Sculptor

    NASA Astrophysics Data System (ADS)

    Vincenzo, F.; Matteucci, F.; de Boer, T. J. L.; Cignoni, M.; Tosi, M.

    2016-08-01

    We present a novel approach to draw the synthetic color-magnitude diagram of galaxies, which can provide - in principle - a deeper insight in the interpretation and understanding of current observations. In particular, we `light up' the stars of chemical evolution models, according to their initial mass, metallicity and age, to eventually understand how the assumed underlying galaxy formation and evolution scenario affects the final configuration of the synthetic CMD. In this way, we obtain a new set of observational constraints for chemical evolution models beyond the usual photospheric chemical abundances. The strength of our method resides in the very fine grid of metallicities and ages of the assumed database of stellar isochrones. In this work, we apply our photo-chemical model to reproduce the observed CMD of the Sculptor dSph and find that we can reproduce the main features of the observed CMD. The main discrepancies are found at fainter magnitudes in the main sequence turn-off and sub-giant branch, where the observed CMD extends towards bluer colors than the synthetic one; we suggest that this is a signature of metal-poor stellar populations in the data, which cannot be captured by our assumed one-zone chemical evolution model.

  10. A fibre-optic mode-filtered light sensor for general and fast chemical assay

    NASA Astrophysics Data System (ADS)

    Zhou, Leiji; Wang, Kemin; Choi, Martin M. F.; Xiao, Dan; Yang, Xiaohai; Chen, Rui; Tan, Weihong

    2004-01-01

    A simple and fast-response fibre-optic chemical sensor based on mode-filtered light detection (MFLD) has been successfully developed. The sensor was constructed by inserting an unmodified fibre core into a silica capillary tubing; a charge-coupled device which acted as a multi-channel detector was positioned alongside the capillary to detect the emanated mode-filtered light. An interesting finding was observed: there was an increase in the signal upon the decrease in the sample refractive index when an unclad optical fibre was employed, which was different from the results of a polymer-clad fibre reported previously. This phenomenon of opposite signal trend can clearly be interpreted by applying a mathematical derivation based on light propagation in the optical fibre. The derived mathematical model correlates well with the experimental results. It also provides a good theoretical foundation for the future development of MFLD-based analyser in conjunction with liquid chromatographic separation and assay. The proposed MFLD sensor was successfully applied to determine acetic acid with a linear response in the range 0-90 v/v % and a correlation coefficient of 0.9959. The sensor has the advantages of high S/N ratio and very fast response time. It offers the potential for use as a general sensor in food and chemical industries.

  11. Brooding light intensity effects on broiler performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Light intensity is an environmental factor which is used with a high degree of variation throughout the US Broiler Industry. Light intensity influences bird activity, immune response, growth rate and has been used to alleviate mortality issues related to metabolic disease (spiking mortality). The ...

  12. Pharmacological and Chemical Effects of Cigarette Additives

    PubMed Central

    Rabinoff, Michael; Caskey, Nicholas; Rissling, Anthony; Park, Candice

    2007-01-01

    We investigated tobacco industry documents and other sources for evidence of possible pharmacological and chemical effects of tobacco additives. Our findings indicated that more than 100 of 599 documented cigarette additives have pharmacological actions that camouflage the odor of environmental tobacco smoke emitted from cigarettes, enhance or maintain nicotine delivery, could increase the addictiveness of cigarettes, and mask symptoms and illnesses associated with smoking behaviors. Whether such uses were specifically intended for these agents is unknown. Our results provide a clear rationale for regulatory control of tobacco additives. PMID:17666709

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

    ERIC Educational Resources Information Center

    Wohlfarth, H.

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

  14. Real-time detection of concealed chemical hazards under ambient light conditions using Raman spectroscopy.

    PubMed

    Cletus, Biju; Olds, William; Fredericks, Peter M; Jaatinen, Esa; Izake, Emad L

    2013-07-01

    Current concerns regarding terrorism and international crime highlight the need for new techniques for detecting unknown and hazardous substances. A novel Raman spectroscopy-based technique, spatially offset Raman spectroscopy (SORS), was recently devised for noninvasively probing the contents of diffusely scattering and opaque containers. Here, we demonstrate a modified portable SORS sensor for detecting concealed substances in-field under different background lighting conditions. Samples including explosive precursors, drugs, and an organophosphate insecticide (chemical warfare agent surrogate) were concealed inside diffusely scattering packaging including plastic, paper, and cloth. Measurements were carried out under incandescent and fluorescent light as well as under daylight to assess the suitability of the probe for different real-life conditions. In each case, it was possible to identify the substances against their reference Raman spectra in less than 1 min. The developed sensor has potential for rapid detection of concealed hazardous substances in airports, mail distribution centers, and customs checkpoints. PMID:23692353

  15. Equine cutaneous amyloidosis derived from an immunoglobulin lambda-light chain. Immunohistochemical, immunochemical and chemical results.

    PubMed

    Linke, R P; Geisel, O; Mann, K

    1991-09-01

    Amyloid deposits from equine cutaneous nodular amyloidosis associated with extramedullary plasmacytoma were classified immunohistochemically as equine immunoglobulin lambda-light chain-derived and designated eA lambda (HIP). For chemical identification, the amyloid fibril proteins were separated on Sephadex G-100 in 6M guanidine.HCl. Polypeptides of predominantly 24 kDa and 50 kDa were found by polyacrylamide gel electrophoresis. They have preponderance of immunoglobulin lambda-antigenic determinants as detected by immunodiffusion and immunoblotting. Since the N-terminus of the major proteins was blocked, peptides were generated with trypsin and endoproteinase Asp-N and then isolated using reversed-phase high-performance liquid chromatography. Automatic amino-acid sequence determination of seven peptides showed novel sequences. Data bank comparison indicated that these peptides were derived from a monoclonal immunoglobulin lambda-light and a gamma-heavy chain. The light chain was considered to be the leading amyloidogenic polypeptide, since it was the predominant component in a virtually pure amyloid fibril preparation. Thus, immunoglobulin lambda-light chain-derived amyloidosis, so far established only in man and cat, has now also been identified in the horse. PMID:1772596

  16. Melanopsin Is Highly Resistant to Light and Chemical Bleaching in Vivo*

    PubMed Central

    Sexton, Timothy J.; Golczak, Marcin; Palczewski, Krzysztof; Van Gelder, Russell N.

    2012-01-01

    Melanopsin is the photopigment of mammalian intrinsically photosensitive retinal ganglion cells, where it contributes to light entrainment of circadian rhythms, and to the pupillary light response. Previous work has shown that the melanopsin photocycle is independent of that used by rhodopsin (Tu, D. C., Owens, L. A., Anderson, L., Golczak, M., Doyle, S. E., McCall, M., Menaker, M., Palczewski, K., and Van Gelder, R. N. (2006) Inner retinal photoreception independent of the visual retinoid cycle. Proc. Natl. Acad. Sci. U.S.A. 103, 10426–10431). Here we determined the ability of apo-melanopsin, formed by ex vivo UV light bleaching, to use selected chromophores. We found that 9-cis-retinal, but not all-trans-retinal or 9-cis-retinol, is able to restore light-dependent ipRGC activity after bleaching. Melanopsin was highly resistant to both visible-spectrum photic bleaching and chemical bleaching with hydroxylamine under conditions that fully bleach rod and cone photoreceptor cells. These results suggest that the melanopsin photocycle can function independently of both rod and cone photocycles, and that apo-melanopsin has a strong preference for binding cis-retinal to generate functional pigment. The data support a model in which retinal is continuously covalently bound to melanopsin and may function through a reversible, bistable mechanism. PMID:22547062

  17. Role of chemical reactions of arylamine hole transport materials in operational degradation of organic light-emitting diodes

    SciTech Connect

    Kondakov, Denis Y.

    2008-10-15

    We report that the representative arylamine hole transport materials undergo chemical transformations in operating organic light-emitting diode (OLED) devices. Although the underlying chemical mechanisms are too complex to be completely elucidated, structures of several identified degradation products point at dissociations of relatively weak carbon-nitrogen and carbon-carbon bonds in arylamine molecules as the initiating step. Considering the photochemical reactivities, the bond dissociation reactions of arylamines occur by the homolysis of the lowest singlet excited states formed by recombining charge carriers in the operating OLED device. The subsequent chemical reactions are likely to yield long-lived, stabilized free radicals capable of acting as deep traps--nonradiative recombination centers and fluorescence quenchers. Their presence in the hole transport layer results in irreversible hole trapping and manifests as a positive fixed charge. The extent and localization of chemical transformations in several exemplary devices suggest that the free radical reactions of hole transporting materials, arylamines, can be sufficient to account for the observed luminance efficiency loss and voltage rise in operating OLEDs. The relative bond strengths and excited state energies of OLED materials appear to have a determining effect on the operational stability of OLED devices.

  18. Conversion of light hydrocarbon gases to metal carbides for production of liquid fuels and chemicals

    SciTech Connect

    Diaz, A.F.; Modestino, A.J.; Howard, J.B.; Peters, W.A.

    1993-02-01

    Light hydrocarbon gases could be reacted with low cost alkaline earth metal oxide (CaO, MgO) in high-temperature plasma reactor to achieve very high ([le]100%) gas conversion to H[sub 2], CO, and the corresponding metal carbides. These carbides could be stored, transported, and hydrolyzed to acetylene or methyl acetylene, which in turn could be upgraded to a wide range of chemicals and premium liquid hydrocarbon fuels. An electric arc discharge reactor was built for converting methane. Literature reviews were made.

  19. Structurally Integrated Photoluminescent Chemical and Biological Sensors: An Organic Light-Emitting Diode-Based Platform

    NASA Astrophysics Data System (ADS)

    Shinar, J.; Shinar, R.

    The chapter describes the development, advantages, challenges, and potential of an emerging, compact photoluminescence-based sensing platform for chemical and biological analytes, including multiple analytes. In this platform, the excitation source is an array of organic light-emitting device (OLED) pixels that is structurally integrated with the sensing component. Steps towards advanced integration with additionally a thin-film-based photodetector are also described. The performance of the OLED-based sensing platform is examined for gas-phase and dissolved oxygen, glucose, lactate, ethanol, hydrazine, and anthrax lethal factor.

  20. The fungicidal effect of ultraviolet light on impression materials

    SciTech Connect

    Ishida, H.; Nahara, Y.; Tamamoto, M.; Hamada, T. )

    1991-04-01

    The effects of ultraviolet (UV) light on fungi and impression materials were tested. UV light (250 microW/cm2) killed most Candida organisms (10(3) cells/ml) within 5 minutes. UV light (8000 microW/cm2) killed most C. albicans (10(7) cells/ml) within 2 minutes of exposure. The effect of UV light on dimensional change and surface roughness of impression materials (irreversible hydrocolloid, agar, and silicone rubber) was tested. The results showed that neither dimensional change nor surface roughness of the impression materials were affected. The results of this study indicate that UV light disinfects impression materials that are contaminated with Candida organisms.

  1. Lighting up stars in chemical evolution models: the CMD of Sculptor

    NASA Astrophysics Data System (ADS)

    Vincenzo, F.; Matteucci, F.; de Boer, T. J. L.; Cignoni, M.; Tosi, M.

    2016-08-01

    We present a novel approach to draw the synthetic colour-magnitude diagram (CMD) of galaxies, which can provide - in principle - a deeper insight in the interpretation and understanding of current observations. In particular, we `light up' the stars of chemical evolution models, according to their initial mass, metallicity and age, to eventually understand how the assumed underlying galaxy formation and evolution scenario affects the final configuration of the synthetic CMD. In this way, we obtain a new set of observational constraints for chemical evolution models beyond the usual photospheric chemical abundances. The strength of our method resides in the very fine grid of metallicities and ages of the assumed data base of stellar isochrones. In this work, we apply our photochemical model to reproduce the observed CMD of the Sculptor dSph and find that we can reproduce the main features of the observed CMD. The main discrepancies are found at fainter magnitudes in the main sequence turn-off and sub-giant branch, where the observed CMD extends towards bluer colours than the synthetic one; we suggest that this is a signature of metal-poor stellar populations in the data, which cannot be captured by our assumed one-zone chemical evolution model.

  2. The effect of sterilization methods on the light transmission characteristics and structure of light-curing tips.

    PubMed

    Kakaboura, A; Tzoutzas, J; Pitsinigos, D; Vougiouklakis, G

    2004-09-01

    The purpose of this study was to investigate the effect of various sterilization methods on the light transmission and the structural characteristics of two light-curing tips. Twenty tips from two light-curing devices [Elipar II (EL) and Heliolux II (HL)] were classified into four groups. The tips in groups A to C were subjected to sterilization with 0.2% sodium dichloroisacyanurate solution (Presept), 2% glutaraldehyde solution (Cidex) (2 h cycle(-1)) and water-steam autoclave (120 degrees C, 1 bar, 12 min cycle(-1)), respectively. A total of 2100 sterilization cycles was performed for all methods tested. The transmitted light intensity (TLI) was measured at specific sterilization time intervals by a curing radiometer (Model 100, Demetron). The final % TLI reduction of the sterilized tips was calculated relative to the corresponding control ones. The topography and composition of the front curing tip surfaces were determined using scanning electron microscopy combined with electron probe microanalyser. Autoclaving caused the lowest final TLI decrease (EL: 15%, HL: 19%) compared with Presept (EL: 60%, HL: 42%) and with Cidex (EL: 68%, HL: 52%). Cidex yielded higher TLI drop than Presept for both types of tips examined. Elipar tips were found to be more sensitive than Heliolux tips to both chemical sterilization techniques. Total or partial coating of the tip surfaces with insoluble salts after sterilization with Presept and Cidex was detected, mainly composed of Ca, Cl, Al, Pd and Mg traces. No changes were noted on the surfaces after autoclave. Water-steam autoclave is safer than the 0.2% sodium dicloroisocyanorate and 2% glutaraldehyde chemical sterilization agents regarding the light transmission characteristics and the structure of the light-curing tips. PMID:15369476

  3. Optical and chemical characterization of aerosols emitted from coal, heavy and light fuel oil, and small-scale wood combustion.

    PubMed

    Frey, Anna K; Saarnio, Karri; Lamberg, Heikki; Mylläri, Fanni; Karjalainen, Panu; Teinilä, Kimmo; Carbone, Samara; Tissari, Jarkko; Niemelä, Ville; Häyrinen, Anna; Rautiainen, Jani; Kytömäki, Jorma; Artaxo, Paulo; Virkkula, Aki; Pirjola, Liisa; Rönkkö, Topi; Keskinen, Jorma; Jokiniemi, Jorma; Hillamo, Risto

    2014-01-01

    Particle emissions affect radiative forcing in the atmosphere. Therefore, it is essential to know the physical and chemical characteristics of them. This work studied the chemical, physical, and optical characteristics of particle emissions from small-scale wood combustion, coal combustion of a heating and power plant, as well as heavy and light fuel oil combustion at a district heating station. Fine particle (PM1) emissions were the highest in wood combustion with a high fraction of absorbing material. The emissions were lowest from coal combustion mostly because of efficient cleaning techniques used at the power plant. The chemical composition of aerosols from coal and oil combustion included mostly ions and trace elements with a rather low fraction of absorbing material. The single scattering albedo and aerosol forcing efficiency showed that primary particles emitted from wood combustion and some cases of oil combustion would have a clear climate warming effect even over dark earth surfaces. Instead, coal combustion particle emissions had a cooling effect. Secondary processes in the atmosphere will further change the radiative properties of these emissions but are not considered in this study. PMID:24328080

  4. Effect of light sources and light intensity on growth performance and behavior of male turkeys.

    PubMed

    Leighton, A T; Hulet, R M; Denbow, D M

    1989-09-01

    This study consisted of two experiments: the first was conducted with Large White turkey males during the spring and summer (experiment 1) and the second during the autumn and winter (experiment 2). When 56 d of age, the birds were assigned to light-controlled pens and exposed to continuous illumination. Light sources used were incandescent, daylight fluorescent, warm fluorescent or high pressure sodium vapour lamps at light intensities of 10.8 or 86.1 lux. Results obtained showed that the light sources used had no significant effects on growth performance, efficiency of food utilization, feather scores or live bird quality of Large White turkeys. Social encounters were higher in birds reared under fluorescent and sodium vapour lights and mortality was higher in birds under fluorescent lights in experiment 1. Behaviour, feather scores, live bird grade and mortality were unaffected by light source treatments in experiment 2. Light intensity had no significant effect on growth, efficiency of food utilization, feather scores or bird market quality. Social encounters and mortality were higher in males exposed to 86.1 lux of light intensity. PMID:2819500

  5. Lighting.

    SciTech Connect

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  6. Electromagnetic effects on the light hadron spectrum

    SciTech Connect

    Basak, S.; et al.

    2015-10-16

    Calculations studying electromagnetic eff ects on light mesons are reported. The calculations use fully dynamical QCD, but only quenched photons, which suffi ces to NLO in χ PT; that is, the sea quarks are electrically neutral, while the valence quarks carry charge. The non-compact formalism is used for photons. New results are obtained with lattice spacing as small as 0.045 fm and a large range of volumes. The success of chiral perturbation theory in describing these results and the implications for light quark masses are considered.

  7. Effects of School Lighting on Physical Development and School Performance.

    ERIC Educational Resources Information Center

    Hathaway, Warren E.

    1995-01-01

    This study collected data on the physical development, attendance, and school performance effects of four types of school lighting on elementary students over a two-year period. Results indicated that regular exposure to the lights had important nonvisual effects on students. Full-spectrum fluorescent lamps with ultraviolet supplements were found…

  8. Conquering the Pumpkin Effect: A Lighting Alternative.

    ERIC Educational Resources Information Center

    Stanley, Gary B.

    1993-01-01

    Turning off all the interior and exterior lighting when school buildings are closed saves money. In a small Illinois school district, nearly $14,000 were saved in electrical expenditures for six buildings. Another Illinois district currently has 19 of its 32 buildings blacked out at night and saves over $150,000 annually. Vandalism and loitering…

  9. Effect of ultraviolet light on toxicity of the PAH fluoranthene to freshwater organisms

    SciTech Connect

    Brooke, L.T.; Cox, D.; Kahl, M.; Spehar, R.L.

    1994-12-31

    Certain polyaromatic hydrocarbons (PAHs) can be activated by irradiation with ultraviolet light in the near UV waveband to increase their biocidal qualities. Fluoranthene is one of the PAHs that has this capacity. Ten species of freshwater animals and one species of freshwater plant were acutely exposed to several concentrations of fluoranthene in the presence of additional UV light and to standard light conditions. Tests were conducted using flow-through static or renewal techniques. Fluoranthene concentrations were measured using high pressure liquid chromatography. UV light was produced by UV-emitting fluorescent lamps. UV-C was removed from the spectrum by cellulose triacetate filters. Separate measurements were made of spectral ranges 310 to 390, 265 to 328 and < 320 nm. All species tested except for a dragonfly, Ophiogomphus sp. were more sensitive to fluoranthene in the presence of UV light ranging from 449 to 926 {mu}W/CM{sup 2} than the same species exposed to this chemical in tests using standard light conditions. Sensitivity increased by factors of {<=}32 times in these tests. Two species were tested for effects of UV light during chronic exposure. The cladoceran, Daphnia magna, showed a 17.1 fold increase in sensitivity to fluoranthene due to UV light and the fathead minnow showed a 5.77 fold increase. Results show that water quality criteria for fluoranthene should be adjusted for UV light effects.

  10. Isotope effects in photo dissociation of ozone with visible light

    NASA Astrophysics Data System (ADS)

    Früchtl, Marion; Janssen, Christof; Röckmann, Thomas

    2014-05-01

    Ozone (O3) plays a key role for many chemical oxidation processes in the Earth's atmosphere. In these chemical reactions, ozone can transfer oxygen to other trace gases. This is particularly interesting, since O3 has a very peculiar isotope composition. Following the mass dependent fractionation equation δ17O = 0.52 * δ18O, most fractionation processes depend directly on mass. However, O3 shows an offset to the mass dependent fractionation line. Processes, which show such anomalies, are termed mass independent fractionations (MIF). A very well studied example for a chemical reaction that leads to mass independent fractionation is the O3 formation reaction. To what degree O3 destruction reactions need to be considered in order to understand the isotope composition of atmospheric O3 is still not fully understood and an open question within scientific community. We set up new experiments to investigate the isotope effect resulting from photo dissociation of O3 in the Chappuis band (R1). Initial O3 is produced by an electric discharge. After photolysis O3 is collected in a cold trap at the triple point temperature of nitrogen (63K). O3 is then converted to O2 in order to measure the oxygen isotopes of O3 using isotope ratio mass spectrometry. To isolate O3 photo dissociation (R1) from O3 decomposition (R2) and secondary O3 formation (R3), we use varying amounts of carbon monoxide (CO) as O atom quencher (R4). In this way we suppress the O + O3 reaction (R3) and determine the isotope fractionation in R1 and R2 separately. We present first results on the isotope effects in O3 photo dissociation with visible light in the presence of different bath gases. Results are interpreted based on chemical kinetics modeling. (R1) O3 + hυ → O (3P) + O2 (R2) O3 + O (3P) → 2 O2 (R3) O + O2 + M → O3 + M (R4) O (3P) + CO + M → CO2 + M

  11. Acute effects of bright light exposure on cortisol levels.

    PubMed

    Jung, Christopher M; Khalsa, Sat Bir S; Scheer, Frank A J L; Cajochen, Christian; Lockley, Steven W; Czeisler, Charles A; Wright, Kenneth P

    2010-06-01

    Multisynaptic neural and endocrine pathways from the suprachiasmatic nucleus of the hypothalamus have been hypothesized to communicate circadian and photic information to the adrenal glands. In humans, light exposure has been reported to have no effect, increase, or decrease cortisol levels. These inconsistent findings in humans may be related to differences among studies including the intensity (approximately 500 to 5500 lux), duration (15 min to 4 h), and circadian phase of light exposure. The authors assessed the influence of exposure to bright light on cortisol levels in humans during the rising and descending phases of the circadian rhythm of cortisol, that is, when cortisol levels are high. Twenty healthy men and women were studied using a within-subject research design. Subjects were studied in an environment free of time cues for 9 to 10 days. Subjects received a 6.7-h exposure of bright light (approximately 10,000 lux; equivalent to ambient light intensity just after sunrise or just before sunset) or dim light (approximately 3 lux; equivalent to candle light) during the biological night and morning. Bright light exposure significantly reduced plasma cortisol levels at both circadian phases studied, whereas dim light exposure had little effect on cortisol levels. The finding of an acute suppressive effect of bright light exposure on cortisol levels supports the existence of a mechanism by which photic information can acutely influence the human adrenal glands. PMID:20484692

  12. Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise.

    PubMed

    Youngstedt, Shawn D; Kline, Christopher E; Elliott, Jeffrey A; Zielinski, Mark R; Devlin, Tina M; Moore, Teresa A

    2016-01-01

    Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210-2340 h, (2) treadmill exercise alone from 2210-2340 h, or (3) bright light (2210-2340 h) followed by exercise from 0410-0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect. PMID:27103935

  13. Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise

    PubMed Central

    Kline, Christopher E.; Elliott, Jeffrey A.; Zielinski, Mark R.; Devlin, Tina M.; Moore, Teresa A.

    2016-01-01

    Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210–2340 h, (2) treadmill exercise alone from 2210–2340 h, or (3) bright light (2210–2340 h) followed by exercise from 0410–0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect. PMID:27103935

  14. Competition between the tensor light shift and nonlinear Zeeman effect

    SciTech Connect

    Chalupczak, W.; Wojciechowski, A.; Pustelny, S.; Gawlik, W.

    2010-08-15

    Many precision measurements (e.g., in spectroscopy, atomic clocks, quantum-information processing, etc.) suffer from systematic errors introduced by the light shift. In our experimental configuration, however, the tensor light shift plays a positive role enabling the observation of spectral features otherwise masked by the cancellation of the transition amplitudes and creating resonances at a frequency unperturbed either by laser power or beam inhomogeneity. These phenomena occur thanks to the special relation between the nonlinear Zeeman and light shift effects. The interplay between these two perturbations is systematically studied and the cancellation of the nonlinear Zeeman effect by the tensor light shift is demonstrated.

  15. The effect of light color on muscular strength and power.

    PubMed

    Crane, Daniel K; Hensarling, Robert W; Jung, Alan P; Sands, Charles D; Petrella, John K

    2008-06-01

    The purpose of this study was to assess the effect of the color of light in a room on muscular strength and power. A convenience sample of 18 men (M age = 20.4 yr., SD = 1.2) performed a modified Wingate Anaerobic Cycle Test for muscular power and a hand grip strength test in each of the following conditions: red, blue, and white (neutral) ambient light. A repeated-measures multivariate analysis of variance indicated that average muscular power was significantly higher when performing the test in the room with red light compared to rooms lit with blue light or white light. The results also indicated that grip strength was significantly higher in the room lit with white light as compared to the room lit with blue light. PMID:18712217

  16. Quantum spin Hall effect of light

    NASA Astrophysics Data System (ADS)

    Bliokh, Konstantin Y.; Smirnova, Daria; Nori, Franco

    2015-06-01

    Maxwell’s equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell’s theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces.

  17. OPTICS. Quantum spin Hall effect of light.

    PubMed

    Bliokh, Konstantin Y; Smirnova, Daria; Nori, Franco

    2015-06-26

    Maxwell's equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell's theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces. PMID:26113717

  18. Light Quality Effects on Corn Chloroplast Development

    PubMed Central

    Eskins, Kenneth; Duysen, Murray; Dybas, Linda; McCarthy, Susan

    1985-01-01

    Corn was grown under greenhouse and controlled light quality conditions incluing full spectrum, red (R), and far-red (FR) sources. Young leaf samples were analyzed for pigments, pigment-proteins, membrane polypeptides, and ultrastructure. Chloroplast development in full spectrum white light was similar to that found in R but different from that found in FR plus low R. Compared to greenhouse and R, FR plus low R (670-760) repressed the formation of photosystem I reaction center protein (CP1 + CP1a) and enhanced those of photosystem II (CPa) in both bundle sheath and mesophyll cells. Photosystem II polypeptides were present in both cell types, with the 46 and 34 kilodalton proteins predominant in mesophyll cells. Bundle sheath cells contained relatively more of the 51 kilodalton and less of the 46 kilodalton proteins. However, they also contained measurable amounts of ribulose bisphosphate carboxylase which may interfere with estimates of the 51 kilodalton protein. Images Fig. 4 PMID:16664023

  19. Effect of 670-nm Light-Emitting Diode Light On Neuronal Cultures

    NASA Technical Reports Server (NTRS)

    Wong-Riley, Margaret T. T.; Whelan, Harry T.

    2002-01-01

    Light close to and within the near infrared range has documented benefits for promoting wound healing in human and animal studies. Our preliminary results using light-emitting diodes (LEDs) in this range have also demonstrated two-to five-fold increases in growth-phase-specific DNA synthesis in normal fibroblasts, muscle cells, osteoblasts, and mucosal epithelial cells in tissue cultures. However, the mechanisms of action of such light on cells are poorly understood. We hypothesized that the therapeutic effects of such light result from the stimulation of cellular events associated with increases in cytochrome oxidase activity. As a first step in testing our hypothesis, we subjected primary neuronal cultures to impulse blockade by tetrodotoxin (TTX), a voltage-dependent sodium channel blocker, and applied LED light at 670 nm to determine if it could partially or fully reverse the reduction of cytochrome oxidase activity by TTX. The wavelength and parameters were previously tested to be beneficial for wound healing.

  20. Encapsulation effects on carbonaceous aerosol light absorption

    SciTech Connect

    Sedlacek, A.J.; Onasch, T.; Davidovits, P.; Cross, E.; Mazzoleni, C.

    2010-03-15

    The contribution of aerosol absorption on direct radiative forcing is still an active area of research, in part, because aerosol extinction is dominated by light scattering and, in part, because the primary absorbing aerosol of interest, soot, exhibits complex aging behavior that alters its optical properties. The consequences of this can be evidenced by the work of Ramanathan and Carmichael (2008) who suggest that incorporating the atmospheric heating due to brown clouds (plumes containing soot byproducts from automobiles, biomass burning, wood-burning kitchen stoves, and coal-fired power plants) will increase black carbon (BC) radiative forcing from the Intergovernmental Panel on Climate Change best estimate of 0.34 Wm-2 (±0.25 Wm-2) (IPCC 2007) to 0.9 Wm-2. This noteworthy degree of uncertainty is due largely to the interdependence of BC optical properties on particle mixing state and aggregate morphology, each of which changes as the particle ages in the atmosphere and becomes encapsulated within a coating of inorganic and/or organic substances. In July 2008, a laboratory-based measurement campaign, led by Boston College and Aerodyne, was initiated to begin addressing this interdependence. To achieve insights into the interdependence of BC optical properties on particle mixing state and aggregate morphology, measurements of both the optical and physical properties of flame-generated soot under nascent, coated, and denuded conditions were conducted. This poster presents data on black carbon (BC) light absorption measured by Photothermal Interferometry (Sedlacek and Lee 2007). In addition to examining nascent BC—to provide a baseline measurement—encapsulation with varying thicknesses of either dioctyl sebacate (DOS) or sulfuric acid was conducted to glean insights into the interplay between particle mixing state and optical properties. Additionally, some experiments were carried out where BC was coated and then denuded. In the case of DOS-coated soot, a

  1. Wet Chemical Controllable Synthesis of Hematite Ellipsoids with Structurally Enhanced Visible Light Property

    PubMed Central

    Han, Chengliang; Han, Jie; Li, Qiankun; Xie, Jingsong

    2013-01-01

    A facile and economic route has been presented for mass production of micro/nanostructured hematite microcrystals based on the wet chemical controllable method. The as-prepared samples were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-Vis absorption spectroscopy. The results showed that the product was mesoporous α-Fe2O3 and nearly elliptical in shape. Each hematite ellipsoid was packed by many α-Fe2O3 nanoparticles. The values of vapor pressure in reaction systems played vital roles in the formation of porous hematite ellipsoids. Optical tests demonstrated that the micro/nanostructured elliptical hematite exhibited enhanced visible light property at room temperature. The formation of these porous hematite ellipsoids could be attributed to the vapor pressure induced oriented assembling of lots of α-Fe2O3 nanoparticles. PMID:24222735

  2. The Detailed Chemical Properties of M31 Star Clusters. I. Fe, Alpha and Light Elements

    NASA Astrophysics Data System (ADS)

    Colucci, Janet E.; Bernstein, Rebecca A.; Cohen, Judith G.

    2014-12-01

    We present ages, [Fe/H] and abundances of the α elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters (GCs) in M31, which were obtained from high-resolution, high signal-to-noise ratio >60 echelle spectra of their integrated light (IL). All abundances and ages are obtained using our original technique for high-resolution IL abundance analysis of GCs. This sample provides a never before seen picture of the chemical history of M31. The GCs are dispersed throughout the inner and outer halo, from 2.5 kpc < R M31 < 117 kpc. We find a range of [Fe/H] within 20 kpc of the center of M31, and a constant [Fe/H] ~ - 1.6 for the outer halo clusters. We find evidence for at least one massive GC in M31 with an age between 1 and 5 Gyr. The α-element ratios are generally similar to the Milky Way GC and field star ratios. We also find chemical evidence for a late-time accretion origin for at least one cluster, which has a different abundance pattern than other clusters at similar metallicity. We find evidence for star-to-star abundance variations in Mg, Na, and Al in the GCs in our sample, and find correlations of Ca, Mg, Na, and possibly Al abundance ratios with cluster luminosity and velocity dispersion, which can potentially be used to constrain GC self-enrichment scenarios. Data presented here were obtained with the HIRES echelle spectrograph on the Keck I telescope. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  3. THE DETAILED CHEMICAL PROPERTIES OF M31 STAR CLUSTERS. I. Fe, ALPHA AND LIGHT ELEMENTS

    SciTech Connect

    Colucci, Janet E.; Bernstein, Rebecca A.; Cohen, Judith G.

    2014-12-20

    We present ages, [Fe/H] and abundances of the α elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters (GCs) in M31, which were obtained from high-resolution, high signal-to-noise ratio >60 echelle spectra of their integrated light (IL). All abundances and ages are obtained using our original technique for high-resolution IL abundance analysis of GCs. This sample provides a never before seen picture of the chemical history of M31. The GCs are dispersed throughout the inner and outer halo, from 2.5 kpc < R {sub M31} < 117 kpc. We find a range of [Fe/H] within 20 kpc of the center of M31, and a constant [Fe/H] ∼ – 1.6 for the outer halo clusters. We find evidence for at least one massive GC in M31 with an age between 1 and 5 Gyr. The α-element ratios are generally similar to the Milky Way GC and field star ratios. We also find chemical evidence for a late-time accretion origin for at least one cluster, which has a different abundance pattern than other clusters at similar metallicity. We find evidence for star-to-star abundance variations in Mg, Na, and Al in the GCs in our sample, and find correlations of Ca, Mg, Na, and possibly Al abundance ratios with cluster luminosity and velocity dispersion, which can potentially be used to constrain GC self-enrichment scenarios. Data presented here were obtained with the HIRES echelle spectrograph on the Keck I telescope.

  4. Effects of laryngoscope handle light source on the light intensity from disposable laryngoscope blades.

    PubMed

    Milne, A D; Brousseau, P A; Brousseau, C A

    2014-12-01

    A bench-top study was performed to assess the effects of different laryngoscope handles on the light intensity delivered from disposable metal or plastic laryngoscope blades. The light intensity from both the handle light sources themselves and the combined handle and laryngoscope blade sets was measured using a custom-designed testing system and light meter. Five samples of each disposable blade type were tested and compared with a standard re-usable stainless steel blade using three different handle/light sources (Vital Signs LED, Heine 2.5 V Xenon and 3.5 V Xenon). The light intensity delivered by the disposable blades ranged from 790 to 3846 lux for the different handle types. Overall, the 3.5 V Heine handle delivered the highest light output (p < 0.007) in comparison with the other handles. For the disposable blades, the overall light output was significantly higher from the plastic than the metal blades (p < 0.001). PMID:25040627

  5. Chromophore-immobilized luminescent metal-organic frameworks as potential lighting phosphors and chemical sensors.

    PubMed

    Wang, Fangming; Liu, Wei; Teat, Simon J; Xu, Feng; Wang, Hao; Wang, Xinlong; An, Litao; Li, Jing

    2016-08-11

    An organic chromophore H4tcbpe-F was synthesized and immobilized into metal-organic frameworks along with two bipyridine derivatives as co-ligands to generate two strongly luminescent materials [Zn2(tcbpe-F)(4,4'-bpy)·xDMA] (1) and [Zn2(tcbpe-F)(bpee)·xDMA] (2) [4,4'-bpy = 4,4'-bipyridine, bpee = 4,4'-bipyridyl-ethylene, tcbpe-F = 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(3-fluoro-[1,1'-biphenyl]-4-carboxylic acid), DMA = N,N-dimethylacetamide]. Compounds 1 and 2 are isoreticular and feature a 2-fold interpenetrated three-dimensional porous structure. Both compounds give green-yellow emission under blue light excitation. Compound 1 has a high internal quantum yield of ∼51% when excited at 455 nm and shows selective luminescence signal change (e.g. emission energy and/or intensity) towards different solvents, including both aromatic and nonaromatic volatile organic species. These properties make it potentially useful as a lighting phosphor and a chemical sensor. PMID:27465685

  6. Light-sensitized decontamination of ground-water hazardous chemicals. Technical report (Final)

    SciTech Connect

    Larson, R.A.; Schlauch, M.B.; Ellis, D.D.; Marley, K.A.; Ju, H.L.

    1988-01-01

    The use of sunlight, oxygen, and dissolved organic compounds active as 'photosensitizers' (substances capable of absorbing sunlight and transforming it into chemically useful forms) is a promising treatment for contaminated waters. Light is absorbed by the sensitizing substance, raising it to a higher energy excited state. Reaction with the excited state substance converts molecular oxygen to a form much more reactive with dissolved compounds. Riboflavin (Vitamin B2), a naturally occurring compound and a known photosensitizer, was investigated for use in this process. A series of kinetic experiments explored its ability to photodegrade several aromatic compounds, phenols and anilines, that are related to some herbicides (such as carbaryl, 2, 4-D, alachlor, atrazine, and trifluralin) commonly found in polluted waters. It was found that riboflavin when added to solutions of phenols or anilines greatly accelerated the rate of their loss in the presence of light. The sensitized photolysis rates increased in the absence of oxygen, suggesting a mechanism involving direct energy or electron transfer between flavin excited states and acceptor molecules. In addition, it was found that some iron salts were very significant promoters of photodestruction of the triazine herbicide, atrazine.

  7. Centrifugal photovoltaic and photogalvanic effects driven by structured light

    PubMed Central

    Wätzel, J.; Berakdar, J.

    2016-01-01

    Much efforts are devoted to material structuring in a quest to enhance the photovoltaic effect. We show that structuring light in a way it transfers orbital angular momentum to semiconductor-based rings results in a steady charge accumulation at the outer boundaries that can be utilized for the generation of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current. This effect which stems both from structuring light and matter confinement potentials, can be magnified even at fixed moderate intensities, by increasing the orbital angular momentum of light which strengthens the effective centrifugal potential that repels the charge outwards. Based on a full numerical time propagation of the carriers wave functions in the presence of light pulses we demonstrate how the charge buildup leads to a useable voltage or directed photocurrent whose amplitudes and directions are controllable by the light pulse parameters. PMID:26900105

  8. Effects of light on gravitaxis and velocity in Chlamydomonas reinhardtii.

    PubMed

    Sineshchekov, O; Lebert, M; Hader, D P

    2000-09-01

    The effects of light on gravitaxis and velocity in the bi-flagellated green alga Chlamydomonas reinhardtii were investigated using a real time automatic tracking system. Three distinct light effects on gravitaxis and velocity with parallel kinetics were found. Photosynthetically active continuous red light reversibly enhances the swimming velocity and increases or decreases the precision of gravitaxis, depending on its initial level. Blue light flashes induce fast transient increases in velocity immediately after the photophobic response, and transiently decrease or even reverse negative gravitaxis. The calcium dependence of this response, its fluence-response curve and its spectral characteristics strongly suggest the participation of chlamy-rhodopsin in this effect. The third response, a prolonged activation of velocity and gravitaxis, is also induced by blue light flashes, which can be observed even in calcium-free medium. PMID:12090268

  9. Centrifugal photovoltaic and photogalvanic effects driven by structured light

    NASA Astrophysics Data System (ADS)

    Wätzel, J.; Berakdar, J.

    2016-02-01

    Much efforts are devoted to material structuring in a quest to enhance the photovoltaic effect. We show that structuring light in a way it transfers orbital angular momentum to semiconductor-based rings results in a steady charge accumulation at the outer boundaries that can be utilized for the generation of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current. This effect which stems both from structuring light and matter confinement potentials, can be magnified even at fixed moderate intensities, by increasing the orbital angular momentum of light which strengthens the effective centrifugal potential that repels the charge outwards. Based on a full numerical time propagation of the carriers wave functions in the presence of light pulses we demonstrate how the charge buildup leads to a useable voltage or directed photocurrent whose amplitudes and directions are controllable by the light pulse parameters.

  10. Origins of light trans-Fe and r-process elements deduced from Galactic chemical evolution

    NASA Astrophysics Data System (ADS)

    Ishimaru, Yuhri; Arao, Sachie; Wanajo, Shinya; Prantzos, Nicolas

    2014-09-01

    Compact binary mergers are suggested to be the major site of the r-process elements by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however, that estimated long lifetimes of compact binaries are in conflict with the presence of large scatters in r-process elements of very metal-poor stars (MPS). To resolve this problem, we examine the role of compact binary mergers in the early Galactic chemical evolution on the assumption that our Galactic halo was formed from clusterings of sub-halos. We find that star-to-star scatters of [r/Fe] in MPS can be well explained with this scenario. Observations of MPS also show large enhancement of Sr relative to Ba, suggesting a distinct site of light trans-Fe elements. Recent nucleosynthesis studies show that electron-capture supernovae (ECSNe) can produce heavy elements up to Zr (Wanajo et al. 2011). Using our inhomogeneous chemical evolution model, we discuss that ECSNe can explain observed enhancement of Zn in MPS as well as of Sr, Y, and Zr.

  11. Non-Visual Effects of Classroom Lighting on Children.

    ERIC Educational Resources Information Center

    Hathaway, Warren E.

    1993-01-01

    A two-year study in Alberta on the effects of classroom lighting found that elementary school students exposed to full-spectrum lighting with measurable ultraviolet output had fewer dental caries, larger gains in height and weight, larger gains in achievement, and better attendance. Students exposed to high-pressure sodium vapor lamps had the…

  12. The Effects of Blue Light on Ocular Health.

    ERIC Educational Resources Information Center

    Kitchel, Elaine

    2000-01-01

    This review of the literature examines the effects of blue light (or near UV - ultraviolet), especially that given off by black-light tubes, often used with children with visual impairments. It finds a long-term danger of retinal and lens damage and offers six practical suggestions which emphasize using proper filters and limiting exposure to…

  13. Non-Visual Effects of Classroom Lighting on Children.

    ERIC Educational Resources Information Center

    Hathaway, Warren E.

    1994-01-01

    Results from a pilot study of four different lighting systems indicate that over a two-year period, light had measurable and significant effects on students. Under full-spectrum fluorescent lamps with ultraviolet enhancement, students developed fewer dental cavities and had better attendance, achievement, and growth and development than students…

  14. Quantifying phosphorus and light effects in stream algae

    SciTech Connect

    Hill, Walter; Fanta, S.E.; Roberts, Brian J

    2009-01-01

    Simultaneous gradients of phosphorus and light were applied in experimental streams to develop quantitative relationships between these two important abiotic variables and the growth and composition of benthic microalgae. Algal biovolume and whole-stream metabolism responded hyperbolically to phosphorus enrichment, increasing approximately two-fold over the 5-300 g L-1 range of experimental phosphorus concentrations. The saturation threshold for phosphorus effects occurred at 25 g L-1 of soluble reactive phosphorus (SRP). Light effects were much stronger than those of phosphorus, resulting in a nearly ten-fold increase in algal biovolume over the 10-400 mol photons m-2 s-1 range of experimental irradiances. Biovolume accrual was light-saturated at 100 mol photons m-2 s-1 (5 mol photons m-2 d-1). Light effects were diminished by low phosphorus concentrations, and phosphorus effects were diminished by low irradiances, but evidence of simultaneous limitation by both phosphorus and light at subsaturating irradiances was weak. Contrary to the light:nutrient hypothesis, algal phosphorus content was not significantly affected by light, even in the lowest SRP treatments. However, algal nitrogen content increased substantially at lower irradiances, and it was very highly correlated with algal chlorophyll a content. Phosphorus enrichment in streams is likely to have its largest effect at concentrations <25 g L-1 SRP, but the effect of enrichment is probably minimized when streambed irradiances are kept below 2 mol photons m-2 d-1 by riparian shading or turbidity

  15. Chemical amplification of magnetic field effects relevant to avian magnetoreception.

    PubMed

    Kattnig, Daniel R; Evans, Emrys W; Déjean, Victoire; Dodson, Charlotte A; Wallace, Mark I; Mackenzie, Stuart R; Timmel, Christiane R; Hore, P J

    2016-04-01

    Magnetic fields as weak as the Earth's can change the yields of radical pair reactions even though the energies involved are orders of magnitude smaller than the thermal energy, kBT, at room temperature. Proposed as the source of the light-dependent magnetic compass in migratory birds, the radical pair mechanism is thought to operate in cryptochrome flavoproteins in the retina. Here we demonstrate that the primary magnetic field effect on flavin photoreactions can be amplified chemically by slow radical termination reactions under conditions of continuous photoexcitation. The nature and origin of the amplification are revealed by studies of the intermolecular flavin-tryptophan and flavin-ascorbic acid photocycles and the closely related intramolecular flavin-tryptophan radical pair in cryptochrome. Amplification factors of up to 5.6 were observed for magnetic fields weaker than 1 mT. Substantial chemical amplification could have a significant impact on the viability of a cryptochrome-based magnetic compass sensor. PMID:27001735

  16. Tumorigenesis in athymic nude mouse skin by chemical carcinogens and ultraviolet light

    SciTech Connect

    Anderson, L.M.; Rice, J.M.

    1987-01-01

    A variety of established skin tumorigenesis protocols were tested for efficacy on athymic nu/nu mice (BALB/c background) and compared on euthymic nu/+ counterparts. Chemical carcinogens and UV light were applied to the ears of 10 mice of each sex and genotype for each group. Treatments were: 0.5 mg 7,12-dimethylbenz(a)anthracene ((DMBA) CAS: 57-97-6) to each ear; 0.125 mg DMBA to each ear, followed by 0.1 microgram 12-O-tetradecanoylphorbol-13-acetate ((TPA) CAS: 16561-29-8) twice weekly for 56 weeks; 0.2 mg N-nitroso-N-methylurea ((NMU) CAS: 684-93-5; 1% in acetone, 20 microliter) to each ear; 0.1 mg NMU to each ear weekly for 30 weeks; 0.2 mg NMU to each ear, followed by TPA twice weekly for 56 weeks; two ip doses of N-nitroso-N-ethylurea ((NEU) CAS: 759-73-9; 25 mg/kg each), followed by TPA twice weekly topically for 56 weeks; and exposure to sunlamps (250- to 400-nm emission) two or three times per week for 20 weeks, for a total dose of 3.7 X 10(5) J/m2. The chemical treatments caused mainly squamous papillomas and carcinomas, sebaceous adenomas and adenocarcinomas, and basal cell tumors, which appeared both on the skin of the ears and elsewhere. UV light caused squamous tumors, basal cell tumors, and sarcomas. Ear skin of the nu/nu mice developed significantly more squamous tumors than those of nu/+ mice after DMBA-TPA, NMU-TPA, NEU-TPA, repeated NMU, or UV light. Similar results were obtained for the skin of the heads and bodies. Even a single dose of NMU caused a few tumors on the nude, but not the euthymic, mice. A single dose of DMBA caused primarily sebaceous adenomas, distributed at random over the entire bodies. These results show that, contrary to previous reports, nude mice are sensitive to skin tumorigenesis, more so than euthymic nu/+ mice similarly exposed to diverse types of carcinogen and treatment protocols.

  17. Daily variation and effects of ambient light and circadian factors on the human light reflex.

    PubMed

    Fosnaugh, J S; Bunker, E B; Pickworth, W B

    1992-09-01

    Measures of pupillary size and the dynamic light reflex are safe and noninvasive methods to quantify and characterize the mechanism and site of drug action. The effects of variations in ambient light and time of day on pupillary measures were determined. In dark adapted volunteers (n = 13), ambient light was incrementally increased at < 0.1, 4, 40, 100 and 200 foot-candle (ftcd). Subjects adjusted to each light level for 1 min before the light reflex was elicited. Replicate measures were collected with the contralateral eye open and covered with an opaque patch. Data were collected every 3 h between 6 a.m. and 9 p.m. The prestimulus diameter of the dark adapted pupil averaged 6.4 mm at < 0.1 ftcd and 2.3 mm at 200 ftcd. Constriction amplitude decreased with increases in ambient light from 2.1 mm (< 0.1 ftcd) to 0.2 mm (200 ftcd) while constriction and dilatation velocities decreased from 7.7 to 2.8 mm/sec and 4.3 to 2.8 mm/sec, respectively. Time of day effects were small but statistically significant and the interaction of ambient light and time of recording suggests the pupil is differentially sensitive to ambient and phasic light stimuli over the course of the day. A patch over the contralateral eye increased pupil size and velocities of the light reflex. In a second study, 10 volunteers were tested twice a day at 4 and 80 ftcd for four days. While there was wide between subject variability, the within subject differences were small. Such baseline data may be useful in describing the normal variations in these increasingly popular indices of drug action. PMID:1287379

  18. Chemical effect on diffusion in intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Ting

    With the trend of big data and the Internet of things, we live in a world full of personal electronic devices and small electronic devices. In order to make the devices more powerful, advanced electronic packaging such as wafer level packaging or 3D IC packaging play an important role. Furthermore, ?-bumps, which connect silicon dies together with dimension less than 10 ?m, are crucial parts in advanced packaging. Owing to the dimension of ?-bumps, they transform into intermetallic compound from tin based solder after the liquid state bonding process. Moreover, many new reliability issues will occur in electronic packaging when the bonding materials change; in this case, we no longer have tin based solder joint, instead, we have intermetallic compound ?-bumps. Most of the potential reliability issues in intermetallic compounds are caused by the chemical reactions driven by atomic diffusion in the material; thus, to know the diffusivities of atoms inside a material is significant and can help us to further analyze the reliability issues. However, we are lacking these kinds of data in intermetallic compound because there are some problems if used traditional Darken's analysis. Therefore, we considered Wagner diffusivity in our system to solve the problems and applied the concept of chemical effect on diffusion by taking the advantage that large amount of energy will release when compounds formed. Moreover, by inventing the holes markers made by Focus ion beam (FIB), we can conduct the diffusion experiment and obtain the tracer diffusivities of atoms inside the intermetallic compound. We applied the technique on Ni3Sn4 and Cu3Sn, which are two of the most common materials in electronic packaging, and the tracer diffusivities are measured under several different temperatures; moreover, microstructure of the intermetallic compounds are investigated to ensure the diffusion environment. Additionally, the detail diffusion mechanism was also discussed in aspect of diffusion

  19. Effect of lighting conditions on zebrafish growth and development.

    PubMed

    Villamizar, Natalia; Vera, Luisa María; Foulkes, Nicholas Simon; Sánchez-Vázquez, Francisco Javier

    2014-04-01

    In the underwater environment, the properties of light (intensity and spectrum) change rapidly with depth and water quality. In this article, we have described how and to what extent lighting conditions can influence the development, growth, and survival of zebrafish. Fertilized eggs and the corresponding larvae were exposed to different visible light wavelengths (violet, blue, green, yellow, red, and white) in a 12-h light-12-h dark (LD) cycle until 30 days posthatching (dph), when the expression of morphometric parameters and growth (igf1a, igf2a)- and stress-related (crh and pomca) genes were examined. Another group of larvae was raised under constant darkness (DD) until 5 or 10 dph, after which they were transferred to a LD of white light. A third group remained under DD to investigate the effects of light deprivation upon zebrafish development. The results revealed that the hatching rate was highest under blue and violet light, while total length at 30 dph was greatest under blue, white, and violet light. Red light led to reduced feeding activity and poor survival (100% mortality). Larvae raised under constant white light (LL) showed a higher proportion of malformations, as did larvae raised under LD violet light. The expression of growth and stress factors was upregulated in the violet (igf1a, igf2a, pomca, and chr) and blue (igf2a) groups, which is consistent with the higher growth recorded and the higher proportion of malformations detected under the violet light. All larvae kept under DD died before 18 dph, but the survival rates improved in larvae transferred to LD at 5 dph and at 10 dph. In summary, these findings revealed that lighting conditions are crucial factors influencing zebrafish larval development and growth. PMID:24367902

  20. Potential Biological and Ecological Effects of Flickering Artificial Light

    PubMed Central

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

    2014-01-01

    Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered. PMID:24874801

  1. [Effect of Light Color Temperature on Human Concentration and Creativity].

    PubMed

    Weitbrecht, W U; Bärwolff, H; Lischke, A; Jünger, S

    2015-06-01

    Light has different biological effects depending on the color temperature and intensity. This may be the reason for its differing effects. We investigated the influence of color temperature (3000 K, 4500 K, 6000 K) under constant high intensity (1000 Lux) on concentration and creativity of 50 students and employees of the Cologne University of Applied Sciences, Campus Gummersbach (age: 30.9 +/- 10.8y.). As test method we used d2-bq-test, creativity test (mean of the number of ideas on 5 themes), word test and logic test. In addition, test subjects were asked to evaluate their impression of light by means of a questionnaire. To exclude the circadian influence and learning effects on the result, we performed tests at the same time of the day using a random order of color temperature. We found that creativity was better under warm light (3000 K) than under colder light (4500 K, 6000 K). Concentration was best under cold light (6000 K). Under the same light intensity conditions, subjects judged blue light (6000 K) to be brighter than red light (3000 K). PMID:26098084

  2. Effect of various visible light photoinitiators on the polymerization and color of light-activated resins.

    PubMed

    Arikawa, Hiroyuki; Takahashi, Hideo; Kanie, Takahito; Ban, Seiji

    2009-07-01

    The purpose of this study was to investigate effects of various visible light photoinitiators on the polymerization efficiency and color of the light-activated resins. Four photoinitiators, including camphorquinone, phenylpropanedione, monoacrylphosphine oxide (TPO), and bisacrylphosphine oxide (Ir819), were used. Each photoinitiator was dissolved in a Bis-GMA and TEGDMA monomer mixture. Materials were polymerized using dental quartz-tungsten halogen lamp (QTH), plasma-ark lamp and blue LED light-curing units, and a custom-made violet LED light unit. The degree of monomer conversion and CIE L*a*b* color values of the resins were measured using a FTIR and spectral transmittance meter. The degree of monomer conversions of TPO- and Ir819-containing resins polymerized with the violet-LED unit were higher than camphorquinone-containing resin polymerized with the QTH light-curing unit. The lowest color values were observed for the TPO-containing resin. Our results indicate that the TPO photoinitiator and the violet-LED light unit may provide a useful and improved photopolymerization system for dental light-activated resins. PMID:19721283

  3. Effects of weather conditions, light conditions, and road lighting on vehicle speed.

    PubMed

    Jägerbrand, Annika K; Sjöbergh, Jonas

    2016-01-01

    Light conditions are known to affect the number of vehicle accidents and fatalities but the relationship between light conditions and vehicle speed is not fully understood. This study examined whether vehicle speed on roads is higher in daylight and under road lighting than in darkness, and determined the combined effects of light conditions, posted speed limit and weather conditions on driving speed. The vehicle speed of passenger cars in different light conditions (daylight, twilight, darkness, artificial light) and different weather conditions (clear weather, rain, snow) was determined using traffic and weather data collected on an hourly basis for approximately 2 years (1 September 2012-31 May 2014) at 25 locations in Sweden (17 with road lighting and eight without). In total, the data included almost 60 million vehicle passes. The data were cleaned by removing June, July, and August, which have different traffic patterns than the rest of the year. Only data from the periods 10:00 A.M.-04:00 P.M. and 06:00 P.M.-10:00 P.M. were used, to remove traffic during rush hour and at night. Multivariate adaptive regression splines was used to evaluate the overall influence of independent variables on vehicle speed and nonparametric statistical testing was applied to test for speed differences between dark-daylight, dark-twilight, and twilight-daylight, on roads with and without road lighting. The results show that vehicle speed in general depends on several independent variables. Analyses of vehicle speed and speed differences between daylight, twilight and darkness, with and without road lighting, did not reveal any differences attributable to light conditions. However, vehicle speed decreased due to rain or snow and the decrease was higher on roads without road lighting than on roads with lighting. These results suggest that the strong association between traffic accidents and darkness or low light conditions could be explained by drivers failing to adjust their

  4. Chemical Effects during Storage of Frozen Foods.

    ERIC Educational Resources Information Center

    Powrie, W. D.

    1984-01-01

    Discusses (1) characteristics, interrelationships, and distribution of food constituents (including water) in unfrozen food systems; (2) the freezing process; and (3) chemical changes in food during frozen storage. Protein alterations and lipid oxidation are emphasized. (JN)

  5. Compression effects on electrons for chemical bonding

    NASA Astrophysics Data System (ADS)

    Hu, Anguang; Zhang, Fan

    2014-03-01

    How electrons move under compression as chemical bonds between atoms are broken and formed is central to a number of challenges on the performance of materials in extreme conditions. This is not only associated with the fundamental knowledge of material response to compressive loading but also would advance many aspects of material science towards future energy technologies. First-principles simulations of enthalpy minimization, in various target pressures on chemical transformation bonding pathways, reveal that high pressure can push electrons away from their denser regimes where the kinetic energy rises steeply on compression, causing a destabilization of intramolecular bonds. The high-pressure pushing of electrons from one regime to another thus leads to chemical bond destruction and formation with a cell volume collapse accompanied by a drop in stress components. Determination of such electron pathways following bonding conformations of molecular precursors would then result in a number of chemical transformations for novel materials, including high energy density materials.

  6. Demonstrating the Effects of Light Quality on Plant Growth.

    ERIC Educational Resources Information Center

    Whitesell, J. H.; Garcia, Maria

    1977-01-01

    Describes a lab demonstration that illustrates the effect of different colors or wavelengths of visible light on plant growth and development. This demonstration is appropriate for use in college biology, botany, or plant physiology courses. (HM)

  7. Visible Light Photocatalysis with Nitrogen-Doped Titanium Dioxide Nanoparticles Prepared by Plasma Assisted Chemical Vapor Deposition

    SciTech Connect

    Buzby,S.; Barakat, M.; Lin, H.; Ni, C.; Rykov, S.; Chen, J.; Shah, S.

    2006-01-01

    Nitrogen-doped TiO{sub 2} nanoparticles were synthesized via plasma assisted metal organic chemical vapor deposition. Nitrogen dopant concentration was varied from 0 to 1.61 at. %. The effect of nitrogen ion doping on visible light photocatalysis has been investigated. Samples were analyzed by various analytical techniques such as x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy, and near-edge x-ray absorption fine structure. Titanium tetraisopropoxide was used as the titanium precursor, while rf-plasma-decomposed ammonia was used as the source for nitrogen doping. The N-doped TiO{sub 2} nanoparticles were deposited on stainless steel mesh under a flow of Ar and O2 gases at 600 {sup o}C in a tube reactor. The photocatalytic activity of the prepared N-doped TiO{sub 2} samples was tested by the degradation of 2-chlorophenol (2-CP) in an aqueous solution using a visible lamp equipped with an UV filter. The efficiency of photocatalytic oxidation of 2-CP was measured using high performance liquid chromatography. Results obtained revealed the formation of N-doped TiO{sub 2} samples as TiO{sub 2-x}N{sub x}, and a corresponding increase in the visible light photocatalytic activity.

  8. Lighting

    SciTech Connect

    Audin, L.

    1994-12-31

    EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.

  9. Nondipole Effects in Chiral Systems Measured with Linearly Polarized Light

    NASA Astrophysics Data System (ADS)

    Bowen, K. P.; Hemmers, O.; Guillemin, R.; Stolte, W. C.; Piancastelli, M. N.; Lindle, D. W.

    2015-06-01

    With the advent of third-generation synchrotron light sources, it has been demonstrated that higher-order corrections to the dipole approximation are necessary for the description of light-matter interactions in the soft x-ray range. These effects, known as 'nondipole effects', present themselves as asymmetries in the angular distributions of photoelectrons. Chiral molecules, known to have asymmetries in photoelectron angular distributions when exposed to circularly polarized light, have been proposed to demonstrate a chiral-specific nondipole effect when exposed to linearly polarized light. We present the first-ever measurement of nondipole chiral angular distributions for the case of each enantiomer of camphor in the photon energy range 296-343eV.

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

    PubMed

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

    2016-04-01

    Programmable transcription factors can enable precise control of gene expression triggered by a chemical inducer or light. To obtain versatile transgene system with combined benefits of a chemical inducer and light inducer, we created various chimeric promoters through the assembly of different copies of thetetoperator andGal4operator module, which simultaneously responded to a tetracycline-responsive transcription factor and a light-switchable transactivator. The activities of these chimeric promoters can be regulated by tetracycline and blue light synergistically or antagonistically. Further studies of the antagonistic genetic circuit exhibited high spatiotemporal resolution and extremely low leaky expression, which therefore could be used to spatially and stringently control the expression of highly toxic protein Diphtheria toxin A for light regulated gene therapy. When transferring plasmids engineered for the gene switch-driven expression of a firefly luciferase (Fluc) into mice, the Fluc expression levels of the treated animals directly correlated with the tetracycline and light input program. We suggest that dual-input genetic circuits using TET and light that serve as triggers to achieve expression profiles may enable the design of robust therapeutic gene circuits for gene- and cell-based therapies. PMID:26673714

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

    PubMed Central

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

    2016-01-01

    Programmable transcription factors can enable precise control of gene expression triggered by a chemical inducer or light. To obtain versatile transgene system with combined benefits of a chemical inducer and light inducer, we created various chimeric promoters through the assembly of different copies of the tet operator and Gal4 operator module, which simultaneously responded to a tetracycline-responsive transcription factor and a light-switchable transactivator. The activities of these chimeric promoters can be regulated by tetracycline and blue light synergistically or antagonistically. Further studies of the antagonistic genetic circuit exhibited high spatiotemporal resolution and extremely low leaky expression, which therefore could be used to spatially and stringently control the expression of highly toxic protein Diphtheria toxin A for light regulated gene therapy. When transferring plasmids engineered for the gene switch-driven expression of a firefly luciferase (Fluc) into mice, the Fluc expression levels of the treated animals directly correlated with the tetracycline and light input program. We suggest that dual-input genetic circuits using TET and light that serve as triggers to achieve expression profiles may enable the design of robust therapeutic gene circuits for gene- and cell-based therapies. PMID:26673714

  12. Chemical leasing business models: a contribution to the effective risk management of chemical substances.

    PubMed

    Ohl, Cornelia; Moser, Frank

    2007-08-01

    Chemicals indisputably contribute greatly to the well-being of modern societies. Apart from such benefits, however, chemicals often pose serious threats to human health and the environment when improperly handled. Therefore, the European Commission has proposed a regulatory framework for the Registration, Evaluation and Authorization of Chemicals (REACH) that requires companies using chemicals to gather pertinent information on the properties of these substances. In this article, we argue that the crucial aspect of this information management may be the honesty and accuracy of the transfer of relevant knowledge from the producer of a chemical to its user. This may be particularly true if the application of potentially hazardous chemicals is not part of the user's core competency. Against this background, we maintain that the traditional sales concept provides no incentives for transferring this knowledge. The reason is that increased user knowledge of a chemical's properties may raise the efficiency of its application. That is, excessive and unnecessary usage will be eliminated. This, in turn, would lower the amount of chemicals sold and in competitive markets directly decrease profits of the producer. Through the introduction of chemical leasing business models, we attempt to present a strategy to overcome the incentive structure of classical sales models, which is counterproductive for the transfer of knowledge. By introducing two models (a Model A that differs least and a Model B that differs most from traditional sales concepts), we demonstrate that chemical leasing business models are capable of accomplishing the goal of Registration, Evaluation and Authorization of Chemicals: to effectively manage the risk of chemicals by reducing the total quantity of chemicals used, either by a transfer of applicable knowledge from the lessor to the lessee (Model A) or by efficient application of the chemical by the lessor him/herself (Model B). PMID:17958507

  13. Advanced Strategies for Outdoor LED Lighting Applications and Technologies to Curtail Regional Light Pollution Effects

    NASA Astrophysics Data System (ADS)

    Monrad, Christian Karl; Benya, James R.

    2015-08-01

    LED lighting systems for outdoor lighting applications continue to evolve as do strategies to mitigate related effects upon regional astronomical and ecological assets. The improving availability and relative lumen-per-watt efficiencies of blue-suppressed low correlated color temperature emitters, narrow band amber, phosphor converted amber, and various combinations of broadband emitters and sub-550NM and sub-500NM filters allow for a wide palette of choices to be assessed to suit site-specific and task-specific lighting needs. In addition to static spectral content options, readily available luminaire designs also include precise geometric beam shape selections and adaptive controls to include dimming, dynamic spectral shifting, motion detection, and dynamic beam shaping to minimize total environmental lumen emissions throughout the course of the nighttime hours.Regional and international light pollution mitigation regulations will also be briefly addressed in the context of luminaire shielding and spectral content control efforts to better protect human quality of life issues as well as astronomical and ecological interests.The presentation will include numerous spectral content graphs for various luminaire options as well as project-specific case studies to document comparisons of legacy lighting systems versus high-performance LED systems with regard to total lumen emissions, skyglow contributions, energy efficiency, and end-user satisfaction with the installed LED lighting systems. Physical samples of various luminaires will also be available for hands-on assessments.

  14. Light-Activated Amino Acid Transport Systems in Halobacterium halobium Envelope Vesicles: Role of Chemical and Electrical Gradients

    NASA Technical Reports Server (NTRS)

    MacDonald, Russell E.; Greene, Richard V.; Lanyi, Janos K.

    1977-01-01

    The accumulation of 20 commonly occurring L-amino acids by cell envelope vesicles of Halobacterium halobium, in response to light-induced membrane potential and an artificially created sodium gradient, has been studied. Nineteen of these amino acids are actively accumulated under either or both of these conditions. Glutamate is unique in that its uptake is driven only by a chemical gradient for sodium. Amino acid concentrations at half-maximal uptake rates (Km) and maximal transport rates (V(sub max) have been determined for the uptake of all 19 amino acids. The transport systems have been partially characterized with respect to groups of amino acids transported by common carriers, cation effects, and relative response to the electrical and chemical components of the sodium gradient, the driving forces for uptake. The data presented clearly show that the carrier systems, which are responsible for uptake of individual amino acids, are as variable in their properties as those found in other organisms, i. e., some are highly specific for individual amino acids, some transport several amino acids competitively, some are activated by a chemical gradient of sodium only, and some function also in the complete absence of such a gradient. For all amino acids, Na(+) and K(+) are both required for maximal rate of uptake. The carriers for L-leucine and L-histidine are symmetrical in that these amino acids are transported in both directions across the vesicle membrane. It is suggested that coupling of substrate transport to metabolic energy via transient ionic gradients may be a general phenomenon in procaryotes.

  15. Chemical methods for degradation of target proteins using designed light-activatable organic molecules.

    PubMed

    Tanimoto, Shuho; Takahashi, Daisuke; Toshima, Kazunobu

    2012-08-11

    Molecular design, chemical synthesis, and biological evaluation of several designed organic molecules, which target-selectively degrade proteins upon photo-irradiation, are introduced. The designed molecules for protein photo-degradation include 2-phenylquinoline-steroid hormone hybrids and porphyrin derivatives, both of which selectively photo-degrade estrogen receptor-α, and fullerene-sugar and -sulfonic acid hybrids, which selectively photo-degrade HIV-1 protease and amyloid β, respectively. The information will provide a novel and effective way to control specific functions of proteins, and contribute to the molecular design of novel protein photo-degrading agents, which should find wide application in chemistry, biology, and medicine. PMID:22739361

  16. Chemical effect on ozone deposition over seawater

    EPA Science Inventory

    Surface layer resistance plays an important role in determining ozone deposition velocity over seawater. Recent studies suggest that surface layer resistance over sea-water is influenced by wind-speed and chemical interaction at the air-water interface. Here, we investigate the e...

  17. Pathogenic effects of the human chemical biofield.

    PubMed

    Rumyantsev, S N; Grzeszczuk, J

    1995-07-01

    Organisms release their antigens into the environment. Some antigens are volatile and may pass into the blood of other organisms during respiration. Fetal antigens enter the mother's bloodstream through the placenta. Foreign antigens in the blood can cause various chemical changes and may initiate an immune reaction. PMID:8524190

  18. Effects of perfluorinated chemicals on adipocyte development

    EPA Science Inventory

    Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used ...

  19. Rayleigh light scattering measurements of transient gas temperature in a rapid chemical vapor deposition reactor

    SciTech Connect

    Horton, J.F.; Peterson, J.E.

    2000-02-01

    A laser-induced Rayleigh light scattering (RLS) system was used to measure transient gas temperatures in a simulated rapid chemical vapor deposition (RCVD) reactor. The test section geometry was an axisymmetric jet of carrier gas directed down, impinging on a heated water surface. RLS was used to measure instantaneous gas temperature at several locations above the wafer as it was heated from room temperature to 475 K. Gas flow rate and wafer temperature correspond to jet Reynolds number Re{sub i} = 60, wafer maximum Grashof number Gr{sub H} = 4.4 x 10{sup 6}, and a maximum mixed convection parameter Gr{sub H}/Re{sub i}{sup 2} = 1200; all conditions typical of impinging jet reactors common in the numerical literature. Uncertainty of RLS transient temperature from a propagated error analysis was {+-}2--4 K. Peak gas temperature fluctuations were large (in the order of 25 to 75 C). Both flow visualization and RLS measurements showed that the flow field was momentum dominated prior to heating initiation, but became unstable by Gr{sub H}/Re{sub i}{sup 2} = 5. It then consisted of buoyancy-induced plumes and recirculations. Up to the peak wafer temperature, the flow field continued to be highly three-dimensional, unsteady, and dominated by buoyancy. RLS measurements are shown to provide information on carrier gas instantaneous temperature and flow field stability, both critical issues in RCVD processing.

  20. Effect of Pulsing in Low-Level Light Therapy

    PubMed Central

    Hashmi, Javad T.; Huang, Ying-Ying; Sharma, Sulbha K.; Kurup, Divya Balachandran; De Taboada, Luis; Carroll, James D.; Hamblin, Michael R.

    2010-01-01

    Background and Objective Low level light (or laser) therapy (LLLT) is a rapidly growing modality used in physical therapy, chiropractic, sports medicine and increasingly in mainstream medicine. LLLT is used to increase wound healing and tissue regeneration, to relieve pain and inflammation, to prevent tissue death, to mitigate degeneration in many neurological indications. While some agreement has emerged on the best wavelengths of light and a range of acceptable dosages to be used (irradiance and fluence), there is no agreement on whether continuous wave or pulsed light is best and on what factors govern the pulse parameters to be chosen. Study Design/Materials and Methods The published peer-reviewed literature was reviewed between 1970 and 2010. Results The basic molecular and cellular mechanisms of LLLT are discussed. The type of pulsed light sources available and the parameters that govern their pulse structure are outlined. Studies that have compared continuous wave and pulsed light in both animals and patients are reviewed. Frequencies used in other pulsed modalities used in physical therapy and biomedicine are compared to those used in LLLT. Conclusion There is some evidence that pulsed light does have effects that are different from those of continuous wave light. However further work is needed to define these effects for different disease conditions and pulse structures. PMID:20662021

  1. Which chemicals drive biological effects in wastewater and recycled water?

    PubMed

    Tang, Janet Y M; Busetti, Francesco; Charrois, Jeffrey W A; Escher, Beate I

    2014-09-01

    Removal of organic micropollutants from wastewater during secondary treatment followed by reverse osmosis and UV disinfection was evaluated by a combination of four in-vitro cell-based bioassays and chemical analysis of 299 organic compounds. Concentrations detected in recycled water were below the Australian Guidelines for Water Recycling. Thus the detected chemicals were considered not to pose any health risk. The detected pesticides in the wastewater treatment plant effluent and partially advanced treated water explained all observed effects on photosynthesis inhibition. In contrast, mixture toxicity experiments with designed mixtures containing all detected chemicals at their measured concentrations demonstrated that the known chemicals explained less than 3% of the observed cytotoxicity and less than 1% of the oxidative stress response. Pesticides followed by pharmaceuticals and personal care products dominated the observed mixture effects. The detected chemicals were not related to the observed genotoxicity. The large proportion of unknown toxicity calls for effect monitoring complementary to chemical monitoring. PMID:24874944

  2. Display conditions and lesion detectability: effect of background light

    NASA Astrophysics Data System (ADS)

    Razavi, Mahmood; Hall, Theodore R.; Aberle, Denise R.; Hayrapetian, Alek S.; Loloyan, Mansur; Eldredge, Sandra L.

    1990-08-01

    We assessed the effect of high background light on observer performance for the detection of a variety of chest radiographic abnormalities. Five observers reviewed 66 digital hard copy chest images formatted to 1 1 x 14 inch size under two display conditions: 1) on a specially prepared 1 1 x 14 inch illuminated panel with no peripheral light and 2) on a standard viewing panel designed for 14 x 17 inch radiographs. The images contained one - or more of the following conditions: pneumothorax, interstitial disease, nodules, alveolar process, or no abnormality. The results of receiver operator characteristic analysis show that extraneous light does reduce observer performance and the detectability of nodules, interstitial disease.

  3. The effects of light on man and other mammals

    NASA Technical Reports Server (NTRS)

    Wurtman, R. J.

    1975-01-01

    The present article describes the best-studied extravisual effects of visible and ultraviolet light on humans and other mammals. It also considers the possible biological consequences to man of living in artificially lighted environments that differ significantly from the milieu in which he evolved. Cumulative evidence favors the beneficial influences of sunlight: vitamin D activation, plasma bilirubin elimination, inhibition of pineal melatonin synthesis, etc.

  4. Chemically Compatible Sacrificial Layer-Assisted Lift-Off Patterning Method for Fabrication of Organic Light-Emitting Displays

    NASA Astrophysics Data System (ADS)

    Choi, Wonsuk; Kim, Min-Hoi; Lee, Sin-Doo

    2011-08-01

    We developed a generic platform to pattern combinatorial functional layers composed of different classes of organic materials using a repetitive lift-off method based on a chemically compatible sacrificial layer (SL) for organic light-emitting diodes (OLEDs). The essential features come from the chemically compatible SL of a fluorous-polymer that can be generated by laser-inscription or transfer-printing. The precise registration of lateral patterns of different materials was achieved on a single substrate through a series of SL-assisted lift-off processes. The chemical compatibility of the SL and the stability of the light-emitting characteristics were shown in a fluorous-solvent treated monochrome OLEDs.

  5. Shining light on memory: Effects of bright light on working memory performance.

    PubMed

    Huiberts, L M; Smolders, K C H J; de Kort, Y A W

    2015-11-01

    This study examined whether diurnal non-image forming (NIF) effects of illuminance level on cognitive task performance depend on task difficulty and time of day. We employed a balanced crossover design with two 60-min sessions of 200 vs. 1000 lux at eye level. Digit-span task difficulty was manipulated within subjects (forward (FDST) vs. backward (BDST) digit-span task), n-back task difficulty was manipulated between subjects (n=1, 2, or 3). Bright light exposure improved FDST performance during the final measurement block, especially in the afternoon. In contrast, BDST performance deteriorated slightly under bright light in the afternoon. Two-back performance was significantly worse under bright light in the afternoon, while no effect of illuminance level was found on 3-back performance. Thus, the more difficult BDST was affected differently by light intensity as compared to the easier FDST. N-back accuracy, however, did not confirm this role of task difficulty. Future studies should investigate whether similar results hold for other types of tasks and how other variables (e.g., time of day, physiological arousal, or other task characteristics) may influence the direction and magnitude of NIF effects on performance. PMID:26215575

  6. The phantom light effects in modern car taillight combinations

    NASA Astrophysics Data System (ADS)

    Hahn, Norbert; Klinger, Karsten; Manz, Karl; Lemmer, Uli

    2008-04-01

    There are some interfering elements, which are able to influence the signal functions of a car's rear light. One of these elements is the sensitivity to external light sources, which is able to affect the intensity of the rear lamps by the impact of direct sunrays in a flat angle. Recognition of the signals could be made more difficult or impossible. This effect is called phantom light effect. Today the regulations of the ECE do not contain these influences. To investigate the meaning of the effects to the traffic safety, there has been a test with a sun simulator. The task of this test is to measure the luminance of signals from different actual taillights with and without sunlight. Another part of the investigations are some psychophysical tests involving about 20 persons. The dimension of phantom light effects at taillights will be quantified by the analysis of the luminance pictures. With these cognitions some possibilities to reduce the phantom light effect with little changes in the optical design of taillights will be performed. One example will be shown.

  7. Diurnal Spectral Sensitivity of the Acute Alerting Effects of Light

    PubMed Central

    Rahman, Shadab A.; Flynn-Evans, Erin E.; Aeschbach, Daniel; Brainard, George C.; Czeisler, Charles A.; Lockley, Steven W.

    2014-01-01

    Study Objectives: Previous studies have demonstrated short-wavelength sensitivity for the acute alerting response to nocturnal light exposure. We assessed daytime spectral sensitivity in alertness, performance, and waking electroencephalogram (EEG). Design: Between-subjects (n = 8 per group). Setting: Inpatient intensive physiologic monitoring unit. Participants: Sixteen healthy young adults (mean age ± standard deviation = 23.8 ± 2.7 y). Interventions: Equal photon density exposure (2.8 × 1013 photons/cm2/s) to monochromatic 460 nm (blue) or 555 nm (green) light for 6.5 h centered in the middle of the 16-h episode of wakefulness during the biological day. Results were compared retrospectively to 16 individuals who were administered the same light exposure during the night. Measurements and Results: Daytime and nighttime 460-nm light exposure significantly improved auditory reaction time (P < 0.01 and P < 0.05, respectively) and reduced attentional lapses (P < 0.05), and improved EEG correlates of alertness compared to 555-nm exposure. Whereas subjective sleepiness ratings did not differ between the two spectral conditions during the daytime (P > 0.05), 460-nm light exposure at night significantly reduced subjective sleepiness compared to 555-nm light exposure at night (P < 0.05). Moreover, nighttime 460-nm exposure improved alertness to near-daytime levels. Conclusions: The alerting effects of short-wavelength 460-nm light are mediated by counteracting both the circadian drive for sleepiness and homeostatic sleep pressure at night, but only via reducing the effects of homeostatic sleep pressure during the day. Citation: Rahman SA; Flynn-Evans EE; Aeschbach D; Brainard GC; Czeisler CA; Lockley SW. Diurnal spectral sensitivity of the acute alerting effects of light. SLEEP 2014;37(2):271-281. PMID:24501435

  8. Effects of light on the gravitropic response in plants.

    NASA Astrophysics Data System (ADS)

    Sakai, T.; Suzuki, G.; Ohgishi, M.; Saji, K.; Okada, K.

    Plants show changing of growth pattern responding to the environmental stimuli to adapt themselves to the environment. Our research purpose is to elucidate the function of genes participating in light-induced change of growth and movement in plants. By isolation and analyses of mutants showing defects in light-induced responses in model plants, Arabidopsis thaliana, genes involved in the response are identified. Previous studies reported that the negative gravitropic response in hypocotyl of Arabidopsis is suppressed by red light irradiation. We isolated a red-light hypersensitive mutant, flabby, which shows a random-hypocotyl bending by red light irradiation. The FLABBY gene encodes a protein, which is involved in the auxin transport in hypocotyls. On the other hand, our recent analysis showed that cryptochromes also induce a blue-light dependent, random-hypocotyl bending in the phototropins-defective mutants. Now we are studying on the genetic interactions between FLABBY and photoreceptors (phytochromes, cryptochromes, and phototropins). We discuss the effects of light on the gravitropic response in plants.

  9. Light-Front Holography and Novel Effects in QCD

    SciTech Connect

    Brodsky, Stanley J.; Teramond, Guy F. de

    2009-04-20

    The correspondence between theories in anti-de Sitter space and conformal field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. We identify the AdS coordinate z with an invariant light-front coordinate {zeta} which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schroedinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The mapping of electromagnetic and gravitational form factors in AdS space to their corresponding expressions in light-front theory confirms this correspondence. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates and the behavior of the QCD coupling in the infrared. The distinction between static structure functions such as the probability distributions computed from the square of the light-front wavefunctions versus dynamical structure functions which include the effects of rescattering is emphasized. A new method for computing the hadronization of quark and gluon jets at the amplitude level, an event amplitude generator, is outlined.

  10. Thermal effects of cold light sources used in otologic surgery.

    PubMed

    Aksoy, Fadlullah; Dogan, Remzi; Ozturan, Orhan; Eren, Sabri Baki; Veyseller, Bayram; Gedik, Ozge

    2015-10-01

    The objective of this study was to investigate the thermal effects of cold light sources and endoscopes on the inner ear. 25 male guinea pigs were assigned equally to five groups (1: Halogen-1 min, 2: Halogen-5 min, 3: Xenon-1 min, 4: Xenon-5 min, 5: Controls). After both bullae of the guinea pigs were opened, light sources and endoscopes were positioned in the middle ears of the first four groups for specific time periods. DPOAE and ABR tests were conducted on all animals at the beginning of the study, at the end of surgery, and 2 h after surgery. The temperatures of cold light sources were measured by a thermocouple thermometer, and the surface temperatures of the endoscopes were measured by an infrared thermometer. DPOAE and ABR measurements performed right after and 2 h after surgery in group 1, 2, 3, and 5 did not reveal any significant difference. In group 4, DPOAE values were significantly lower and ABR threshold values were significantly higher than those in the other groups, right after and 2 h after surgery. Thermocouple thermometer readings showed that, after the first minute, the Xenon light source generated significantly more temperature rise than the Halogen light source. The surface temperatures of all endoscopes returned to normal approximately 1 min after light sources were turned off. Our study demonstrated that when an endoscope using a Xenon light source was applied to the middle ear for a specific time periods, inner ear functions deteriorated, as reflected by audiologic tests. PMID:25118982

  11. Light-Front Holography and Novel Effects in QCD

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.

    2008-12-18

    The correspondence between theories in anti-de Sitter space and conformal field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. We identify the AdS coordinate z with an invariant light-front coordinate {zeta} which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schroedinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The mapping of electromagnetic and gravitational form factors in AdS space to their corresponding expressions in light-front theory confirms this correspondence. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates and the behavior of the QCD coupling in the infrared. The distinction between static structure functions such as the probability distributions computed from the square of the light-front wavefunctions versus dynamical structure functions which include the effects of rescattering is emphasized. A new method for computing the hadronization of quark and gluon jets at the amplitude level, an event amplitude generator, is outlined.

  12. Development of InAsSb-based light emitting diodes for chemical sensing systems

    SciTech Connect

    Allerman, A.A.; Kurtz, S.R.; Biefeld, R.M.; Baucom, K.C.; Burkhatt, J.H.

    1998-02-01

    Mid-infrared (3--6 {micro}m) LED`s are being developed for use in chemical sensor systems. As rich, InAsSb heterostructures are particularly suited for optical emitters in the mid-infrared region. The authors are investigating both InAsSb-InAs multiple quantum well (MQW) and InAsSb-InAsP strained layer superlattice (SLS) structures for use as the active region for light emitting diodes (LED`s). The addition of phosphorus to the InAs barriers increases the light and heavy hole splitting and hence reduces non-radiative Auger recombination and provides for better electron and hole confinement in the InAsSb quantum well. Low temperature (< 20 K) photoluminescence (PL) emission from MQW structures is observed between 3.2 to 6.0 {micro}m for InAsSb wells between 70 to 100 {angstrom} and antimony mole fractions between 0.04 to 0.18. Room temperature PL has been observed to 6.4 {micro}m in MQW structures. The additional confinement by InAsP barriers results in low temperature PL being observed over a narrower range (3.2 to 5.0 {micro}m) for the similar well thicknesses with antimony mole fractions between 0.10 to 0.24. Room temperature photoluminescence was observed to 5.8 {micro}m in SLS structures. The addition of a p-AlAsSb layer between the n-type active region (MQW or SLS) and a p-GaAsSb contact layer improves electron confinement of the active region and increases output power by a factor of 4. Simple LED emitters have been fabricated which exhibit an average power at room temperature of > 100 {micro}W at 4.0 {micro}m for SLS active regions. These LED`s have been used to detect CO{sub 2} concentrations down to 24 ppm in a first generation, non-cryogenic sensor system. They will report on the development of novel LED device designs that are expected to lead to further improvements in output power.

  13. The investigation of chemical structure of coal macerals via transmitted-light FT-IR microspectroscopy

    NASA Astrophysics Data System (ADS)

    Xuguang, Sun

    2005-11-01

    The Late Permian coals from South China are characterized by high content of the unique maceral "barkinite" and elemental hydrogen, typically produce high yields of tar, and exhibit significant oil-producing potential. "Barkinite" has been identified as suberinite for a long time, but now many Chinese workers have concluded that "barkinite" is not suberinite, rather it is a distinct maceral. The term "barkinite" was formally certified and named by the State Bureau of Technical Supervision of PR China in 1991, 1995, and 1999, however, it has not been recognized as a scientific term by international coal geologists and the ICCP. Transmitted-light FT-IR microspectroscopy and curve-fitting analysis were used to investigate the chemical structure of "barkinite"; at the same time, parallel studies were also carried out on vitrinite, fusinite, and sporinite. In comparison with other maceral types, the micro-FT-IR spectra of "barkinite" are characterized by very strong intensities of aliphatic CH x stretching vibrations at 3000-2800 cm -1 and deformations at 1460-1450 cm -1, less intense bands from aromatic C dbnd C ring stretching at 1610-1600 cm -1 and aromatic CH out-of-plane deformations at 900-700 cm -1. The aliphatic side-chains in the molecular structure of "barkinite" are longer and less branched. In addition, there also appear intense aliphatic ether C sbnd O sbnd C and alcohol C sbnd O stretching bands at 1100-1000 cm -1, notable aromatic CH stretching vibrations at 3050-3030 cm -1, weak OH stretching bands of water in the 3600-3200 cm -1 range, and rare acid C dbnd O group absorption at 1740-1700 cm -1. Collectively the IR spectral characteristics indicate that "barkinite" is composed of great numbers of long chain aliphatics, a fewer of aromatics and rare of oxygenate components. The chemical structure of "barkinite" show that the high tar yields and the relatively high oil-producing potential of the Late Permian coals from South China are attributable to the

  14. Effect of melatonin on hyperlipidemic nephropathy under constant light exposure.

    PubMed

    Túnez, L; Muñoz, M C; Feijoo-López, A L; Valdvira, E; Bujalance-Arenas, L; Montilla, P

    2002-06-01

    Studies have shown anti-hyperlipidemic actions of melatonin, with pharmacological doses inducing changes in cholesterol levels. This study was designed to evaluate the effect of melatonin on adriamycin-induced (25mg/kg b.w., i.p.) hyperlipidemia under constant light exposure. Melatonin was injected i.p. (1,000 microg/kg b.w./day). Triglycerides, total cholesterol, high-density lipoprotein cholesterol, light-density lipoprotein cholesterol, non-proteic nitrogen compounds (urea and creatinine levels), total protein in serum, proteins eliminated in the urine and melatonin levels in serum and kidney were determined. Results show a decrease in melatonin levels induced by both adriamycin and constant light. Likewise, adriamycin induced significant increases in triglycerides, total cholesterol and light-density lipoprotein cholesterol, and lowered high-density lipoprotein cholesterol levels. Constant light exposure also prompted an increase in LDL-c levels and a decrease in HDL-c values, and intensified the effects of adriamycin on these two lipoproteins. All changes induced by adriamycin and constant light were reverted toward normality by melatonin administration. PMID:12435086

  15. Algorithm to illustrate context using dynamic lighting effects

    NASA Astrophysics Data System (ADS)

    John, Roshy M.; Balasubramanian, T.

    2007-09-01

    With the invention of Ultra-Bright LED, solid state lighting has come to something which is much more efficient and energy saving when compared to conventional incandescent or fluorescent lighting. With the use of proper driver electronics now a days it is possible to install solid state lighting systems with the cost same as that of any other lighting technology. This paper is a part of the research project we are doing in our lab, which deals with using ultra bright LEDs of different colors for lighting applications. The driver electronics are made in such a way that, the color and brightness of the lights will change according to context. For instance, if one of the users is reading a story or listening to music in a Personal Computer or in a hand held device such as a PDA, the lighting systems and the HVAC (Heating Ventilation Air-conditioning) systems will change dramatically according to the content of the story or the music. The vulnerability of solid-state lighting helps to accomplish such an effect. Such a type of system will help the reader to feel the story mentally and physically as well. We developed complete driver electronics for the system using multiple microcomputers and a full software suite which uses complex algorithms to decode the context from text or music and synchronize it to lighting and HVAC information. The paper also presents some case-study statistics which shows the advantage of using the system to teach kindergarten children, deaf and dumb children and for language learning classes.

  16. Effects of dust particle internal structure on light scattering

    NASA Astrophysics Data System (ADS)

    Kemppinen, O.; Nousiainen, T.; Jeong, G. Y.

    2015-07-01

    There is a large variety of internal structures inside atmospheric dust particles, making them inherently inhomogeneous. Such structures may have a large effect on ground-level and atmospheric radiation. So far, dust particle internal structures and their effect on the light scattering properties have proved to be hard to quantify, in part due to challenges in obtaining information about these structures. Recently, internal structures of individual dust particles were revealed through focused ion beam milling and analyzed. Here, we perform a sensitivity study to evaluate the optical impacts of some of the typical internal structures revealed. To obtain suitable model particles, the first step is to generate inhomogeneous particles with varying internal structures by using an algorithm that is based on three-dimensional Voronoi tessellation. The parameters for the particle generation are obtained from studies of real-world Asian dust particles. The second step is to generate homogeneous versions of the generated particles by using an effective-medium approximation, for comparison. Third, light scattering by both versions of these particles is simulated with discrete-dipole approximation code. This allows us to see how different internal structures affect light scattering, and how important it is to account for these structures explicitly. Further, this allows us to estimate the potential inaccuracies caused by using only homogeneous model particles for atmospheric studies and remote sensing measurements. The results show that the effects vary greatly between different kinds of internal structures and single-scattering quantity considered, but for most structure types the effects are overall notable. Most significantly, hematite inclusions in particles impact light scattering heavily. Furthermore, internal pores and hematite-rich coating both affect some form of light scattering noticeably. Based on this work, it seems that it is exceedingly important that the

  17. Effects of dust particle internal structure on light scattering

    NASA Astrophysics Data System (ADS)

    Kemppinen, O.; Nousiainen, T.; Jeong, G. Y.

    2015-10-01

    There is a large variety of internal structures inside atmospheric dust particles, making them inherently inhomogeneous. Such structures may have a large effect on ground-level and atmospheric radiation. So far, dust particle internal structures and their effect on the light scattering properties have proved to be hard to quantify, in part due to challenges in obtaining information about these structures. Recently, internal structures of individual dust particles were revealed through focused ion beam milling and analyzed. Here, we perform a sensitivity study to evaluate the optical impacts of some of the typical internal structures revealed. To obtain suitable model particles, the first step is to generate inhomogeneous particles with varying internal structures by using an algorithm that is based on three-dimensional Voronoi tessellation. The parameters for the particle generation are obtained from studies of real-world Asian dust particles. The second step is to generate homogeneous versions of the generated particles by using an effective-medium approximation, for comparison. Third, light scattering by both versions of these particles is simulated with discrete dipole approximation code. This allows us to see how different internal structures affect light scattering, and how important it is to account for these structures explicitly. Further, this allows us to estimate the potential inaccuracies caused by using only homogeneous model particles for atmospheric studies and remote-sensing measurements. The results show that the effects vary greatly between different kinds of internal structures and single-scattering quantity considered, but for most structure types the effects are overall notable. Most significantly, hematite inclusions in particles impact light scattering heavily. Furthermore, internal pores and hematite-rich coating both affect some form of light scattering noticeably. Based on this work, it seems that it is exceedingly important that the

  18. A rule-based expert system for chemical prioritization using effects-based chemical categories.

    PubMed

    Schmieder, P K; Kolanczyk, R C; Hornung, M W; Tapper, M A; Denny, J S; Sheedy, B R; Aladjov, H

    2014-01-01

    A rule-based expert system (ES) was developed to predict chemical binding to the estrogen receptor (ER) patterned on the research approaches championed by Gilman Veith to whom this article and journal issue are dedicated. The ERES was built to be mechanistically transparent and meet the needs of a specific application, i.e. predict for all chemicals within two well-defined inventories (industrial chemicals used as pesticide inerts and antimicrobial pesticides). These chemicals all lack structural features associated with high affinity binders and thus any binding should be low affinity. Similar to the high-quality fathead minnow database upon which Veith QSARs were built, the ERES was derived from what has been termed gold standard data, systematically collected in assays optimized to detect even low affinity binding and maximizing confidence in the negatives determinations. The resultant logic-based decision tree ERES, determined to be a robust model, contains seven major nodes with multiple effects-based chemicals categories within each. Predicted results are presented in the context of empirical data within local chemical structural groups facilitating informed decision-making. Even using optimized detection assays, the ERES applied to two inventories of >600 chemicals resulted in only ~5% of the chemicals predicted to bind ER. PMID:24779615

  19. EFFECTS OF ENVIRONMENTAL CHEMICALS ON FETAL TESTES TESTOSTERONE PRODUCTION

    EPA Science Inventory

    Effects of Environmental Chemicals on Fetal Testes Testosterone Production

    Lambright, CS , Wilson, VS , Furr, J, Wolf, CJ, Noriega, N, Gray, LE, Jr.
    US EPA, ORD/NHEERL/RTD, RTP, NC

    Exposure of pregnant rodents to certain environmental chemicals during criti...

  20. "EFFECT OF NON-TARGET ORGANICS ON ORGANIC CHEMICAL TRANSPORT."

    EPA Science Inventory

    NRMRL/IO BOOK NRMRL-CIN-1363 Enfield*, C.G., Lien*, B.K., and Wood*, A.L. "Effect of Non-Target Organics on Organic Chemical Transport." Published in: Humic Substances and Chemical Contaminants, Chapter 23, C.E. Clapp, M.H.B. Hayes, et al (Ed.), Madison, WI: So...

  1. Enhancing extraction of light from metal composite structures for plasmonic emitters using light-coupling effect.

    PubMed

    Chiu, Nan-Fu; Yang, Cheng-Du; Kao, Yi-Lun; Lu, Kuan-Lin

    2015-04-20

    This work demonstrates the efficiency and directionality of a method of extracting light from thin-film emissive devices by near-field evanescent waves in plasmonic emitters used in metal composite grating structures. A near-field evanescent wave can induce a surface plasmon wave on the surface of a metal under resonant conditions. Enhancing the near-field evanescent wave generates strong far-field nonlinear optical effects. This effect is highly efficient in some plasmonic emitter structures. Theoretical and experimental results demonstrate that such a metal composite grating structure exhibits good performance, a high coupling ratio, a small coupling angle, enhanced light extraction and a small FWHM. It also improves luminous efficiency, emitter angle, and directivity. PMID:25968996

  2. GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition

    SciTech Connect

    Xu, Kun; Xu, Chen Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei; Xie, Yiyang; Sun, Jie; Mikroteknologi och Nanovetenskap, Chalmers Tekniska Högskola AB, Göteborg 41296

    2013-11-25

    Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300 °C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

  3. Blue light dose–responses of leaf photosynthesis, morphology, and chemical composition of Cucumis sativus grown under different combinations of red and blue light

    PubMed Central

    Hogewoning, Sander W.; Trouwborst, Govert; Maljaars, Hans; Poorter, Hendrik; van Ieperen, Wim; Harbinson, Jeremy

    2010-01-01

    The blue part of the light spectrum has been associated with leaf characteristics which also develop under high irradiances. In this study blue light dose–response curves were made for the photosynthetic properties and related developmental characteristics of cucumber leaves that were grown at an equal irradiance under seven different combinations of red and blue light provided by light-emitting diodes. Only the leaves developed under red light alone (0% blue) displayed dysfunctional photosynthetic operation, characterized by a suboptimal and heterogeneously distributed dark-adapted Fv/Fm, a stomatal conductance unresponsive to irradiance, and a relatively low light-limited quantum yield for CO2 fixation. Only 7% blue light was sufficient to prevent any overt dysfunctional photosynthesis, which can be considered a qualitatively blue light effect. The photosynthetic capacity (Amax) was twice as high for leaves grown at 7% blue compared with 0% blue, and continued to increase with increasing blue percentage during growth measured up to 50% blue. At 100% blue, Amax was lower but photosynthetic functioning was normal. The increase in Amax with blue percentage (0–50%) was associated with an increase in leaf mass per unit leaf area (LMA), nitrogen (N) content per area, chlorophyll (Chl) content per area, and stomatal conductance. Above 15% blue, the parameters Amax, LMA, Chl content, photosynthetic N use efficiency, and the Chl:N ratio had a comparable relationship as reported for leaf responses to irradiance intensity. It is concluded that blue light during growth is qualitatively required for normal photosynthetic functioning and quantitatively mediates leaf responses resembling those to irradiance intensity. PMID:20504875

  4. Is part-night lighting an effective measure to limit the impacts of artificial lighting on bats?

    PubMed

    Azam, Clémentine; Kerbiriou, Christian; Vernet, Arthur; Julien, Jean-François; Bas, Yves; Plichard, Laura; Maratrat, Julie; Le Viol, Isabelle

    2015-12-01

    As light pollution is currently considered to be a major threat to biodiversity, different lighting management options are being explored to mitigate the impact of artificial lighting on wildlife. Although part-night lighting schemes have been adopted by many local authorities across Europe to reduce the carbon footprint and save energy, their effects on biodiversity are unknown. Through a paired, in situ experiment, we compared the activity levels of 8 bat species under unlit, part-night, and full-night lighting treatments in a rural area located 60 km south of Paris, France. We selected 36 study locations composed of 1 lit site and a paired unlit control site; 24 of these sites were located in areas subject to part-night lighting schemes, and 12 sites were in areas under standard, full-night lighting. There was significantly more activity on part-night lighting sites compared to full-night lighting sites for the late-emerging, light-sensitive Plecotus spp., and a similar pattern was observable for Myotis spp., although not significant. In contrast, part-night lighting did not influence the activity of early emerging bat species around streetlights, except for Pipistrellus pipistrellus for which there was significantly less activity on part-night lighting sites than on full-night lighting sites. Overall, no significant difference in activity between part- and full-night lighting sites were observed in 5 of the 8 species studied, suggesting that current part-night lighting schemes fail to encompass the range of activity of most bat species. We recommend that such schemes start earlier at night to effectively mitigate the adverse effects of artificial lighting on light-sensitive species, particularly along ecological corridors that are especially important to the persistence of biodiversity in urban landscapes. PMID:26179558

  5. BIOELECTRIC POTENTIALS IN HALICYSTIS : VIII. THE EFFECTS OF LIGHT.

    PubMed

    Blinks, L R

    1940-03-20

    The effects of light upon the potential difference across the protoplasm of impaled Halicystis cells are described. These effects are very slight upon the normal P.D., increasing it 3 or 4 per cent, or at most 10 per cent, with a characteristic cusped time course, and a corresponding decrease on darkening. Light effects become much greater when the P.D. has been decreased by low O(2) content of the sea water; light restores the P.D. in much the same time course as aeration, and doubtless acts by the photosynthetic production of O(2). There are in both cases anomalous cusps which decrease the P.D. before it rises. Short light exposures may give only this anomaly. Over part of the potential range the light effects are dependent upon intensity. Increased CO(2) content of the sea water likewise depresses the P.D. in the dark, and light overcomes this depression if it is not carried too far. Recovery is probably due to photosynthetic consumption of CO(2), unless there is too much present. Again there are anomalous cusps during the first moments of illumination, and these may be the only effect if the P.D. is too low. The presence of ammonium salts in the sea water markedly sensitizes the cells to light. Subthreshold NH(4) concentrations in the dark become effective in the light, and the P.D. reverses to a negative sign on illumination, recovering again in the dark. This is due to increase of pH outside the cell as CO(2) is photosynthetically reduced, with increase of undissociated NH(3) which penetrates the cell. Anomalous cusps which first carry the P.D. in the opposite direction to the later drift are very marked in the presence of ammonia, and may represent an increased acidity which precedes the alkaline drift of photosynthesis. This acid gush seems to be primarily within the protoplasm, persisting when the sea water is buffered. Glass electrode measurements also indicate anomalies in the pH drift. There are contrary cusps on darkening which suggest temporarily

  6. Effects on the Liver of Chemicals Encountered in the Workplace

    PubMed Central

    Pond, Susan M.

    1982-01-01

    The liver plays a central role in toxicology. It is the primary organ of detoxification and elimination by metabolism of many chemicals. Many workplace chemicals can affect the liver in animals; fewer have been proved to do so in humans. The diverse hepatic effects observed in humans from occupational exposure to chemicals range from fatty infiltration, acute hepatitis and cholestasis to cirrhosis and angiosarcoma. Three important workplace chemicals, prototypes for the toxicities of many others, are carbon tetrachloride, vinyl chloride and the polychlorinated biphenyls (PCB's). These three are described in some detail to highlight principles of occupational toxicology. Most of the hepatic effects produced by chemicals in the workplace have clinical, laboratory and morphological features common to many other forms of liver disease. Therefore, only an astute physician who takes an occupational history will recognize the association between a patient's workplace and liver disease. PMID:6819718

  7. The effect of light-activation sources on tooth bleaching

    PubMed Central

    Baroudi, Kusai; Hassan, Nadia Aly

    2014-01-01

    Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching. PMID:25298598

  8. In Vitro Profiling of Chemical Effects on Steroidogenesis (ASCCT)

    EPA Science Inventory

    Steroidogenesis, including both steroid hormone biosynthesis and metabolism, is critical for proper endocrine function. Disruption of steroidogenesis by environmental chemicals results in altered hormone levels that may cause adverse reproductive and developmental effects. This s...

  9. Engineering a Chemical Switch into the Light-driven Proton Pump Proteorhodopsin by Cysteine Mutagenesis and Thiol Modification.

    PubMed

    Harder, Daniel; Hirschi, Stephan; Ucurum, Zöhre; Goers, Roland; Meier, Wolfgang; Müller, Daniel J; Fotiadis, Dimitrios

    2016-07-25

    For applications in synthetic biology, for example, the bottom-up assembly of biomolecular nanofactories, modules of specific and controllable functionalities are essential. Of fundamental importance in such systems are energizing modules, which are able to establish an electrochemical gradient across a vesicular membrane as an energy source for powering other modules. Light-driven proton pumps like proteorhodopsin (PR) are excellent candidates for efficient energy conversion. We have extended the versatility of PR by implementing an on/off switch based on reversible chemical modification of a site-specifically introduced cysteine residue. The position of this cysteine residue in PR was identified by structure-based cysteine mutagenesis combined with a proton-pumping assay using E. coli cells overexpressing PR and PR proteoliposomes. The identified PR mutant represents the first light-driven proton pump that can be chemically switched on/off depending on the requirements of the molecular system. PMID:27294681

  10. The Effects of Lighting and Interpersonal Distance on Counseling Interactions

    ERIC Educational Resources Information Center

    Dumont, Florent; Lecomte, Conrad

    1975-01-01

    Results showed a significant interactive effect of lighting and distance on the communication of empathy. Requests for reprints should be sent to F. Dumont, McGill University, 3700 McTavish Street, Montreal, P.Q., H3A 1Y2. (Author)

  11. Prediction of Harmful Human Health Effects of Chemicals from Structure

    NASA Astrophysics Data System (ADS)

    Cronin, Mark T. D.

    There is a great need to assess the harmful effects of chemicals to which man is exposed. Various in silico techniques including chemical grouping and category formation, as well as the use of (Q)SARs can be applied to predict the toxicity of chemicals for a number of toxicological effects. This chapter provides an overview of the state of the art of the prediction of the harmful effects of chemicals to human health. A variety of existing data can be used to obtain information; many such data are formalized into freely available and commercial databases. (Q)SARs can be developed (as illustrated with reference to skin sensitization) for local and global data sets. In addition, chemical grouping techniques can be applied on "similar" chemicals to allow for read-across predictions. Many "expert systems" are now available that incorporate these approaches. With these in silico approaches available, the techniques to apply them successfully have become essential. Integration of different in silico approaches with each other, as well as with other alternative approaches, e.g., in vitro and -omics through the development of integrated testing strategies, will assist in the more efficient prediction of the harmful health effects of chemicals

  12. Chemical Exacerbation of Light-induced Retinal Degeneration in F344/N Rats in National Toxicology Program Rodent Bioassays.

    PubMed

    Yamashita, Haruhiro; Hoenerhoff, Mark J; Peddada, Shyamal D; Sills, Robert C; Pandiri, Arun R

    2016-08-01

    Retinal degeneration due to chronic ambient light exposure is a common spontaneous age-related finding in albino rats, but it can also be related to exposures associated with environmental chemicals and drugs. Typically, light-induced retinal degeneration has a central/hemispherical localization whereas chemical-induced retinal degeneration has a diffuse localization. This study was conducted to identify and characterize treatment-related retinal degeneration in National Toxicology Program rodent bioassays. A total of 3 chronic bioassays in F344/N rats (but not in B6C3F1/N mice) were identified that had treatment-related increases in retinal degeneration (kava kava extract, acrylamide, and leucomalachite green). A retrospective light microscopic evaluation of the retinas from rats in these 3 studies showed a dose-related increase in the frequencies of retinal degeneration, beginning with the loss of photoreceptor cells, followed by the inner nuclear layer cells. These dose-related increased frequencies of degenerative retinal lesions localized within the central/hemispherical region are suggestive of exacerbation of light-induced retinal degeneration. PMID:27230502

  13. Reflective liquid crystal light valve with hybrid field effect mode

    NASA Technical Reports Server (NTRS)

    Boswell, Donald D. (Inventor); Grinberg, Jan (Inventor); Jacobson, Alexander D. (Inventor); Myer, Gary D. (Inventor)

    1977-01-01

    There is disclosed a high performance reflective mode liquid crystal light valve suitable for general image processing and projection and particularly suited for application to real-time coherent optical data processing. A preferred example of the device uses a CdS photoconductor, a CdTe light absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The non-coherent light image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the AC voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state (voltage off the liquid crystal) and the optical birefringence effect to create the bright on-state. The liquid crystal thus modulates the polarization of the coherent read-out or projection light responsively to the non-coherent image. An analyzer is used to create an intensity modulated output beam.

  14. Climate-chemical interactions and greenhouse effects of trace gases

    NASA Technical Reports Server (NTRS)

    Shi, Guang-Yu; Fan, Xiao-Biao

    1994-01-01

    A completely coupled one-dimensional radiative-convective (RC) and photochemical-diffusion (PC) model has been developed recently and used to study the climate-chemical interactions. The importance of radiative-chemical interactions within the troposphere and stratosphere has been examined in some detail. We find that increases of radiatively and/or chemically active trace gases such as CO2, CH4 and N2O have both the direct effects and the indirect effects on climate change by changing the atmospheric O3 profile through their interaction with chemical processes in the atmosphere. It is also found that the climatic effect of ozone depends strongly on its vertical distribution throughout the troposphere and stratosphere, as well on its column amount in the atmosphere.

  15. The effects of clouds on the light produced by lightning

    NASA Technical Reports Server (NTRS)

    Thomason, L. W.; Krider, E. P.

    1981-01-01

    A Monte Carlo simulation of the effects of finite clouds on the light impulses was produced by point and finite lightning sources within cubical, cylindrical, and spherical clouds. It is shown that absorption is essentially negligible in the visible and near infrared. The fractions of photons which escape various cloud surfaces are a function of position and geometry of the source. The light emission is high for intracloud discharges and the incloud portion of cloud to ground discharges. It is concluded that the characteristic dimensions of the light escaping from a cloud surface are typically 60 to 70% of the cloud dimensions while the time broadening of an impulse by multiple scattering can be tens of microseconds or more.

  16. NOTE: Fluorescent light effects on FWT-60 radiochromic film

    NASA Astrophysics Data System (ADS)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.

    2005-08-01

    FWT-60 radiochromic film has been tested for colouration effects from fluorescent light sources and shown to produce a marked colouration when exposed to office fluorescent light sources showing an approximate 1 OD unit per 0.5 J m-2 exposure to a broad ultraviolet (UV) UVA + UVB spectrum at the peak absorption wavelength. This produces a measurable and quantifiable response to UV exposure. By choosing an appropriate wavelength of readout or band pass, the level of sensitivity can be changed to match the application or exposure level measurement required. These levels of UV response are significantly higher in sensitivity than other radiochromic films such as Gafchromic MD-55 by an order of magnitude. This feature may be of use for measurement of integrated UV exposure from fluorescent lights when required and produces a quantifiable history of total exposure.

  17. The Red Light District and Its Effects on Zebrafish Reproduction.

    PubMed

    Adatto, Isaac; Krug, Lauren; Zon, Leonard Ira

    2016-06-01

    Light-dark cycles mimicking natural settings in a zebrafish facility are crucial for maintaining fish with an entrained circadian clock making them an ideal vertebrate model to study such rhythms. However, failure to provide optimal conditions to include complete darkness can lead to a disturbed circadian pacemaker affecting physiology and behavior in zebrafish. To meet building code requirements, the aquatics facility in use was outfitted with EXIT signs emitting a constant light. To determine if light radiating from the EXIT sign has an effect on zebrafish embryo production, 100 fish (1:1 m/f ratio) were split and housed at 10 fish/L. Half were housed directly in front of the EXIT sign, whereas the other half (control) were housed under a true 14-h light-10-h dark cycle. Reproductive success was evaluated by recording fecundity and viability from 10 weekly matings under two light colors: red (640 nm) and green (560 nm). On average the control group spawned twice as many embryos compared to those housed in front of a red EXIT sign, whereas green EXIT sign showed no difference. This suggests the importance of providing a complete dark environment within the night cycle and a recommendation toward dim green EXIT signs to avoid a decline in reproductive performance. PMID:26978703

  18. Effects of blue light on pigment biosynthesis of Monascus.

    PubMed

    Chen, Di; Xue, Chunmao; Chen, Mianhua; Wu, Shufen; Li, Zhenjing; Wang, Changlu

    2016-04-01

    The influence of different illumination levels of blue light on the growth and intracellular pigment yields of Monascus strain M9 was investigated. Compared with darkness, constant exposure to blue light of 100 lux reduced the yields of six pigments, namely, rubropunctatamine (RUM), monascorubramine (MOM), rubropunctatin (RUN), monascorubrin (MON), monascin (MS), and ankaflavin (AK). However, exposure to varying levels of blue light had different effects on pigment production. Exposure to 100 lux of blue light once for 30 min/day and to 100 lux of blue light once and twice for 15 min/day could enhance RUM, MOM, MS, and AK production and reduce RUN and MON compared with non-exposure. Exposure to 100 lux twice for 30 min/day and to 200 lux once for 45 min/day decreased the RUM, MOM, MS, and AK yields and increased the RUN and MON. Meanwhile, the expression levels of pigment biosynthetic genes were analyzed by real-time quantitative PCR. Results indicated that gene MpPKS5, mppR1, mppA, mppB, mmpC, mppD, MpFasA, MpFasB, and mppF were positively correlated with the yields of RUN and MON, whereas mppE and mppR2 were associated with RUM, MOM, MS, and AK production. PMID:27033206

  19. New measurements of the EMC effect in light nuclei

    SciTech Connect

    A. Daniel

    2009-12-01

    Modifications of structure functions in nuclei (EMC effect) suggest that the nuclear quark distribution function is not just the incoherent sum of the proton and neutron distributions, and made clear the importance of nuclear effects even in high energy measurements. Jefferson Lab experiment E03-103 made precise measurements of the EMC effect in few-body and heavy nuclei with emphasis on the large x region. Data from the light nuclei suggests that the nuclear dependence of the high x quark distribution may depend on the nucleon's local environment, rather than being a purely bulk effect.

  20. Chemiluminescent Oscillating Demonstrations: The Chemical Buoy, the Lighting Wave, and the Ghostly Cylinder

    ERIC Educational Resources Information Center

    Prypsztejn, Hernan E.; Mulford, Douglas R.; Stratton, Doug

    2005-01-01

    Oscillating reactions have been extensively used in chemical demonstrations. They involve several chemical concepts about kinetics, catalysts, and thermodynamics. The spontaneous cyclic color change of a solution is an attraction in any educational-level course. Chemiluminescent reactions are also among the most fascinating demonstrations and have…

  1. Lead iodide perovskite light-emitting field-effect transistor

    PubMed Central

    Chin, Xin Yu; Cortecchia, Daniele; Yin, Jun; Bruno, Annalisa; Soci, Cesare

    2015-01-01

    Despite the widespread use of solution-processable hybrid organic–inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated by lowering the operating temperature of methylammonium lead iodide perovskite (CH3NH3PbI3) field-effect transistors. Field-effect carrier mobility is found to increase by almost two orders of magnitude below 200 K, consistent with phonon scattering-limited transport. Under balanced ambipolar carrier injection, gate-dependent electroluminescence is also observed from the transistor channel, with spectra revealing the tetragonal to orthorhombic phase transition. This demonstration of CH3NH3PbI3 light-emitting field-effect transistors provides intrinsic transport parameters to guide materials and solar cell optimization, and will drive the development of new electro-optic device concepts, such as gated light-emitting diodes and lasers operating at room temperature. PMID:26108967

  2. Lead iodide perovskite light-emitting field-effect transistor.

    PubMed

    Chin, Xin Yu; Cortecchia, Daniele; Yin, Jun; Bruno, Annalisa; Soci, Cesare

    2015-01-01

    Despite the widespread use of solution-processable hybrid organic-inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated by lowering the operating temperature of methylammonium lead iodide perovskite (CH3NH3PbI3) field-effect transistors. Field-effect carrier mobility is found to increase by almost two orders of magnitude below 200 K, consistent with phonon scattering-limited transport. Under balanced ambipolar carrier injection, gate-dependent electroluminescence is also observed from the transistor channel, with spectra revealing the tetragonal to orthorhombic phase transition. This demonstration of CH3NH3PbI3 light-emitting field-effect transistors provides intrinsic transport parameters to guide materials and solar cell optimization, and will drive the development of new electro-optic device concepts, such as gated light-emitting diodes and lasers operating at room temperature. PMID:26108967

  3. Lead iodide perovskite light-emitting field-effect transistor

    NASA Astrophysics Data System (ADS)

    Chin, Xin Yu; Cortecchia, Daniele; Yin, Jun; Bruno, Annalisa; Soci, Cesare

    2015-06-01

    Despite the widespread use of solution-processable hybrid organic-inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated by lowering the operating temperature of methylammonium lead iodide perovskite (CH3NH3PbI3) field-effect transistors. Field-effect carrier mobility is found to increase by almost two orders of magnitude below 200 K, consistent with phonon scattering-limited transport. Under balanced ambipolar carrier injection, gate-dependent electroluminescence is also observed from the transistor channel, with spectra revealing the tetragonal to orthorhombic phase transition. This demonstration of CH3NH3PbI3 light-emitting field-effect transistors provides intrinsic transport parameters to guide materials and solar cell optimization, and will drive the development of new electro-optic device concepts, such as gated light-emitting diodes and lasers operating at room temperature.

  4. Automatic instrument for chemical processing to detect microorganism in biological samples by measuring light reactions

    NASA Technical Reports Server (NTRS)

    Kelbaugh, B. N.; Picciolo, G. L.; Chappelle, E. W.; Colburn, M. E. (Inventor)

    1973-01-01

    An automated apparatus is reported for sequentially assaying urine samples for the presence of bacterial adenosine triphosphate (ATP) that comprises a rotary table which carries a plurality of sample containing vials and automatically dispenses fluid reagents into the vials preparatory to injecting a light producing luciferase-luciferin mixture into the samples. The device automatically measures the light produced in each urine sample by a bioluminescence reaction of the free bacterial adenosine triphosphate with the luciferase-luciferin mixture. The light measured is proportional to the concentration of bacterial adenosine triphosphate which, in turn, is proportional to the number of bacteria present in the respective urine sample.

  5. Ultraviolet-light-driven doping modulation in chemical vapor deposition grown graphene.

    PubMed

    Iqbal, M Z; Iqbal, M W; Khan, M F; Eom, Jonghwa

    2015-08-28

    The tuning of charge carrier density of graphene is an essential factor to achieve the integration of high-efficiency electronic and optoelectronic devices. We demonstrate the reversible doping in graphene using deep ultraviolet (UV) irradiation and treatment with O2 and N2 gases. The Dirac point shift towards a positive gate voltage of chemical vapor deposition grown graphene field-effect transistors confirms the p-type doping, which is observed under UV irradiation and treatment with O2 gas, while it restores its pristine state after treatment with N2 gas under UV irradiation. The emergence of an additional peak in the X-ray photoelectron spectra during UV irradiation and treatment with O2 gas represents the oxidation of graphene, and the elimination of this peak during UV irradiation and treatment with N2 gas reveals the restoration of graphene in its pristine state. The shift in the G and 2D bands in Raman spectra towards higher and then lower wavenumber also suggests p-type doping and then reversible doping in graphene. The controlled doping and its reversibility in large area grown graphene offer a new vision for electronic applications. PMID:26198203

  6. Ambipolar Light-Emitting Transistors on Chemical Vapor Deposited Monolayer MoS₂.

    PubMed

    Ponomarev, Evgeniy; Gutiérrez-Lezama, Ignacio; Ubrig, Nicolas; Morpurgo, Alberto F

    2015-12-01

    We realize and investigate ionic liquid gated field-effect transistors (FETs) on large-area MoS2 monolayers grown by chemical vapor deposition (CVD). Under electron accumulation, the performance of these devices is comparable to that of FETs based on exfoliated flakes. FETs on CVD-grown material, however, exhibit clear ambipolar transport, which for MoS2 monolayers had not been reported previously. We exploit this property to estimate the bandgap Δ of monolayer MoS2 directly from the device transfer curves and find Δ ≈ 2.4-2.7 eV. In the ambipolar injection regime, we observe electroluminescence due to exciton recombination in MoS2, originating from the region close to the hole-injecting contact. Both the observed transport properties and the behavior of the electroluminescence can be consistently understood as due to the presence of defect states at an energy of 250-300 meV above the top of the valence band, acting as deep traps for holes. Our results are of technological relevance, as they show that devices with useful optoelectronic functionality can be realized on large-area MoS2 monolayers produced by controllable and scalable techniques. PMID:26594892

  7. Circadian-effect engineering of solid-state lighting spectra for beneficial and tunable lighting.

    PubMed

    Dai, Qi; Shan, Qifeng; Lam, Hien; Hao, Luoxi; Lin, Yi; Cui, Zhe

    2016-09-01

    Optimization of solid-state lighting spectra is performed to achieve beneficial and tunable circadian effects. First, the minimum spectral circadian action factor (CAF) of 2700 K white light-emitting diodes (LEDs) is studied for applications where biologically active illumination is undesirable. It is found that white-LEDs based on (i) RGB chips, (ii) blue & red chips plus green phosphor, and (iii) blue chip plus green & red phosphors are the corresponding minimum-CAF solutions at color-rendering index (CRI) requirements of 80, 90, and 95, respectively. Second, maximum CAF tunability of LED clusters is studied for dynamic daylighting applications. A dichromatic phosphor-converted blue-centered LED, a dichromatic phosphor-converted green-centered LED, and a monochromatic red LED are grouped to obtain white spectra between 2700 K and 6500 K. A maximum CAF tunability of 3.25 times is achieved with CRI above 90 and luminous efficacy of radiation of 313 - 373 lm/W. We show that our approaches have advantages over previously reported solutions on system simplicity, minimum achievable CAF value, CAF tunability range, and light source efficacy. PMID:27607613

  8. Understanding the human health effects of chemical mixtures.

    PubMed Central

    Carpenter, David O; Arcaro, Kathleen; Spink, David C

    2002-01-01

    Most research on the effects of chemicals on biologic systems is conducted on one chemical at a time. However, in the real world people are exposed to mixtures, not single chemicals. Although various substances may have totally independent actions, in many cases two substances may act at the same site in ways that can be either additive or nonadditive. Many even more complex interactions may occur if two chemicals act at different but related targets. In the extreme case there may be synergistic effects, in which case the effects of two substances together are greater than the sum of either effect alone. In reality, most persons are exposed to many chemicals, not just one or two, and therefore the effects of a chemical mixture are extremely complex and may differ for each mixture depending on the chemical composition. This complexity is a major reason why mixtures have not been well studied. In this review we attempt to illustrate some of the principles and approaches that can be used to study effects of mixtures. By the nature of the state of the science, this discussion is more a presentation of what we do not know than of what we do know about mixtures. We approach the study of mixtures at three levels, using specific examples. First, we discuss several human diseases in relation to a variety of environmental agents believed to influence the development and progression of the disease. We present results of selected cellular and animal studies in which simple mixtures have been investigated. Finally, we discuss some of the effects of mixtures at a molecular level. PMID:11834461

  9. Integrated chemical treatment of municipal wastewater using waste hydrogen peroxide and ultraviolet light

    NASA Astrophysics Data System (ADS)

    Bhatti, Zulfiqar Ahmed; Mahmood, Qaisar; Raja, Iftikhar Ahmad; Malik, Amir Haider; Rashid, Naim; Wu, Donglei

    Dilemmas like water shortage, rapid industrialization, growing human population and related issues have seriously affected human health and environmental sustainability. For conservation and sustainable use of our water resources, innovative methods for wastewater treatment are continuously being explored. Advance Oxidation Processes (AOPs) show a promising approach to meet specific objectives of municipal wastewater treatment (MWW). The MWW samples were pretreated with Al 2(SO 4) 4·8H 2O (Alum) at different doses 4, 8, 12-50 mg/L to enhance the sedimentation. The maximum COD removal was observed at alum treatments in range of 28-32 mg/L without increasing total dissolved solids (TDS). TDS were found to increase when the alum dose was increased from 32-40 mg/L. In the present study, the optimum alum dose of 30 mg/L for 3 h of sedimentation and subsequent integrated H 2O 2/UV treatment was applied (using 2.5 mL/L of 40% waste H 2O 2 and 35% fresh H 2O 2 separately). Organic and inorganic pollutants, contributing towards chemical oxygen demand (COD), biological oxygen demand (BOD), turbidity and total dissolved solids were degraded by H 2O 2/UV. About 93% COD, 90% BOD and 83% turbidity reduction occurred when 40% waste H 2O 2 was used. When using fresh H 2O 2, 63% COD, 68% BOD and 86% turbidity reduction was detected. Complete disinfection of coliform bacteria occurred by using 40% H 2O 2/UV. The most interesting part of this research was to compare the effectiveness of waste H 2O 2 with fresh H 2O 2. Waste H 2O 2 generated from an industrial process of disinfection was found more effective in the treatment of MWW than fresh 35% H 2O 2.

  10. Reaction efficiency effects on binary chemical reactions

    NASA Astrophysics Data System (ADS)

    Lazaridis, Filippos; Savara, Aditya; Argyrakis, Panos

    2014-09-01

    We study the effect of the variation of reaction efficiency in binary reactions. We use the well-known A + B → 0 model, which has been extensively studied in the past. We perform simulations on this model where we vary the efficiency of reaction, i.e., when two particles meet they do not instantly react, as has been assumed in previous studies, but they react with a probability γ, where γ is in the range 0 < γ < 1. Our results show that at small γ values the system is reaction limited, but as γ increases it crosses over to a diffusion limited behavior. At early times, for small γ values, the particle density falls slower than for larger γ values. This fall-off goes over a crossover point, around the value of γ = 0.50 for high initial densities. Under a variety of conditions simulated, we find that the crossover point was dependent on the initial concentration but not on the lattice size. For intermediate and long times simulations, all γ values (in the depleted reciprocal density versus time plot) converge to the same behavior. These theoretical results are useful in models of epidemic reactions and epidemic spreading, where a contagion from one neighbor to the next is not always successful but proceeds with a certain probability, an analogous effect with the reaction probability examined in the current work.

  11. ENHANCED CHEMICAL CLEANING: EFFECTIVENESS OF THE UV LAMP TO DECOMPOSE OXALATES

    SciTech Connect

    Ketusky, E.; Huff, T.; Sudduth, C.

    2010-01-19

    Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

  12. Local and systemic effects of mechanico-chemical retraction.

    PubMed

    Donaldson, Mark; Goodchild, Jason H

    2013-09-01

    The process of recording an acceptable fixed prosthodontic impression must include appropriate tissue management. This article reviews the effects of mechanical and chemical tissue retraction for fixed prosthodontics, specifically discussing the use of retraction cord with or without chemicals to control sulcular hemorrhage and moisture. Common astringents, hemostatics, and vasoconstrictors used in dentistry as gingival retraction agents are discussed, and recommendations for modification of patient and treatment management are provided. PMID:24350912

  13. Potential Health Effects Associated with Dermal Exposure to Occupational Chemicals

    PubMed Central

    Anderson, Stacey E; Meade, B Jean

    2014-01-01

    There are a large number of workers in the United States, spanning a variety of occupational industries and sectors, who are potentially exposed to chemicals that can be absorbed through the skin. Occupational skin exposures can result in numerous diseases that can adversely affect an individual’s health and capacity to perform at work. In general, there are three types of chemical–skin interactions of concern: direct skin effects, immune-mediated skin effects, and systemic effects. While hundreds of chemicals (metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) present in virtually every industry have been identified to cause direct and immune-mediated effects such as contact dermatitis or urticaria, less is known about the number and types of chemicals contributing to systemic effects. In an attempt to raise awareness, skin notation assignments communicate the potential for dermal absorption; however, there is a need for standardization among agencies to communicate an accurate description of occupational hazards. Studies have suggested that exposure to complex mixtures, excessive hand washing, use of hand sanitizers, high frequency of wet work, and environmental or other factors may enhance penetration and stimulate other biological responses altering the outcomes of dermal chemical exposure. Understanding the hazards of dermal exposure is essential for the proper implementation of protective measures to ensure worker safety and health. PMID:25574139

  14. [Negotiating light therapy. Kellogg versus Finsen, and the controversy about the health effects of light rays around 1900].

    PubMed

    Ingold, Niklaus

    2015-07-01

    Western medicine has produced different rationales for the application of light rays to cure diseases in the 201h century. Since the 1980s, physicians have used bright light for treating mental disorders. In the interwar period, however, physicians regarded ultraviolet rays rather than bright light as medically relevant. This view goes back to the 1890s, when the physician (and later Nobel Price laureate) Niels R. Finsen started treating skin tuberculosis with light rays. However, Finsen was not the only physician who utilized the new electric light to develop effective therapies. Famous American inventor of the breakfast cereal and eugenicists, John Harvey Kellogg used incandescent lamps to heat a sweatbox. Consequently, two different therapeutic schools emerged from these therapeutic experiments. This article shows how these two schools negotiated the use of light therapy and how a specific idea of medically interesting light rays emerged thereby. PMID:26111841

  15. Effect of fixation positions on perception of lightness

    NASA Astrophysics Data System (ADS)

    Toscani, Matteo; Valsecchi, Matteo; Gegenfurtner, Karl R.

    2015-03-01

    Visual acuity, luminance sensitivity, contrast sensitivity, and color sensitivity are maximal in the fovea and decrease with retinal eccentricity. Therefore every scene is perceived by integrating the small, high resolution samples collected by moving the eyes around. Moreover, when viewing ambiguous figures the fixated position influences the dominance of the possible percepts. Therefore fixations could serve as a selection mechanism whose function is not confined to finely resolve the selected detail of the scene. Here this hypothesis is tested in the lightness perception domain. In a first series of experiments we demonstrated that when observers matched the color of natural objects they based their lightness judgments on objects' brightest parts. During this task the observers tended to fixate points with above average luminance, suggesting a relationship between perception and fixations that we causally proved using a gaze contingent display in a subsequent experiment. Simulations with rendered physical lighting show that higher values in an object's luminance distribution are particularly informative about reflectance. In a second series of experiments we considered a high level strategy that the visual system uses to segment the visual scene in a layered representation. We demonstrated that eye movement sampling mediates between the layer segregation and its effects on lightness perception. Together these studies show that eye fixations are partially responsible for the selection of information from a scene that allows the visual system to estimate the reflectance of a surface.

  16. Silicon-Based Chemical Motors: An Efficient Pump for Triggering and Guiding Fluid Motion Using Visible Light

    PubMed Central

    2015-01-01

    We report a simple yet highly efficient chemical motor that can be controlled with visible light. The motor made from a noble metal and doped silicon acts as a pump, which is driven through a light-activated catalytic reaction process. We show that the actuation is based on electro-osmosis with the electric field generated by chemical reactions at the metal and silicon surfaces, whereas the contribution of diffusio-osmosis to the actuation is negligible. Surprisingly, the pump can be operated using water as fuel. This is possible because of the large ζ-potential of silicon, which makes the electro-osmotic fluid motion sizable even though the electric field generated by the reaction is weak. The electro-hydrodynamic process is greatly amplified with the addition of reactive species, such as hydrogen peroxide, which generates higher electric fields. Another remarkable finding is the tunability of silicon-based pumps. That is, it is possible to control the speed of the fluid with light. We take advantage of this property to manipulate the spatial distribution of colloidal microparticles in the liquid and to pattern colloidal microparticle structures at specific locations on a wafer surface. Silicon-based pumps hold great promise for controlled mass transport in fluids. PMID:26349036

  17. Silicon-Based Chemical Motors: An Efficient Pump for Triggering and Guiding Fluid Motion Using Visible Light.

    PubMed

    Esplandiu, Maria J; Farniya, Ali Afshar; Bachtold, Adrian

    2015-11-24

    We report a simple yet highly efficient chemical motor that can be controlled with visible light. The motor made from a noble metal and doped silicon acts as a pump, which is driven through a light-activated catalytic reaction process. We show that the actuation is based on electro-osmosis with the electric field generated by chemical reactions at the metal and silicon surfaces, whereas the contribution of diffusio-osmosis to the actuation is negligible. Surprisingly, the pump can be operated using water as fuel. This is possible because of the large ζ-potential of silicon, which makes the electro-osmotic fluid motion sizable even though the electric field generated by the reaction is weak. The electro-hydrodynamic process is greatly amplified with the addition of reactive species, such as hydrogen peroxide, which generates higher electric fields. Another remarkable finding is the tunability of silicon-based pumps. That is, it is possible to control the speed of the fluid with light. We take advantage of this property to manipulate the spatial distribution of colloidal microparticles in the liquid and to pattern colloidal microparticle structures at specific locations on a wafer surface. Silicon-based pumps hold great promise for controlled mass transport in fluids. PMID:26349036

  18. Slow-light effect via Rayleigh anomaly and the effect of finite gratings

    PubMed Central

    Kim, Kyoung-Youm; Chong, Xinyuan; Ren, Fanghui; Wang, Alan X.

    2016-01-01

    In this Letter, we investigate the slow-light effect of sub-wavelength diffraction gratings via the Rayleigh anomaly using a fully analytical approach without needing to consider specific grating structures. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light–matter interactions for optical sensing and photodetection. However, the slow-light effect will diminish as the transmitted light propagates farther from the grating surface, and the slowdown factor decreases as the grating size shrinks. PMID:26565869

  19. Light-Induced Changes of the Circadian Clock of Humans: Increasing Duration is More Effective than Increasing Light Intensity

    PubMed Central

    Dewan, Karuna; Benloucif, Susan; Reid, Kathryn; Wolfe, Lisa F.; Zee, Phyllis C.

    2011-01-01

    Study Objectives: To evaluate the effect of increasing the intensity and/or duration of exposure on light-induced changes in the timing of the circadian clock of humans. Design: Multifactorial randomized controlled trial, between and within subject design Setting: General Clinical Research Center (GCRC) of an academic medical center Participants: 56 healthy young subjects (20-40 years of age) Interventions: Research subjects were admitted for 2 independent stays of 4 nights/3 days for treatment with bright or dim-light (randomized order) at a time known to induce phase delays in circadian timing. The intensity and duration of the bright light were determined by random assignment to one of 9 treatment conditions (duration of 1, 2, or 3 hours at 2000, 4000, or 8000 lux). Measurements and Results: Treatment-induced changes in the dim light melatonin onset (DLMO) and dim light melatonin offset (DLMOff) were measured from blood samples collected every 20-30 min throughout baseline and post-treatment nights. Comparison by multi-factor analysis of variance (ANOVA) of light-induced changes in the time of the circadian melatonin rhythm for the 9 conditions revealed that changing the duration of the light exposure from 1 to 3 h increased the magnitude of light-induced delays. In contrast, increasing from moderate (2,000 lux) to high (8,000 lux) intensity light did not alter the magnitude of phase delays of the circadian melatonin rhythm. Conclusions: Results from the present study suggest that for phototherapy of circadian rhythm sleep disorders in humans, a longer period of moderate intensity light may be more effective than a shorter exposure period of high intensity light. Citation: Dewan K; Benloucif S; Reid K; Wolfe LF; Zee PC. Light-induced changes of the circadian clock of humans: increasing duration is more effective than increasing light intensity. SLEEP 2011;34(5):593-599. PMID:21532952

  20. Health and environmental effects of complex chemical mixtures: proceedings

    SciTech Connect

    Not Available

    1985-01-01

    The Office of Health and Environmental Research (OHER) of the Department of Energy supports a broad long-term research program on human health and environmental effects from potential exposure to energy-related complex chemical mixtures. The program seeks basic mechanistic data on the effects of complex mixtures at the cellular, molecular, and whole animal levels to aid in predicting human health effects and seeks ecological data on biological and physical transformations in the mixtures, concentrations of the mixtures in various compartments of the environment, and potential routes for human exposure to these mixtures (e.g., food chain). On June 17-18, 1985, OHER held its First Annual Technical Meeting on the Complex Chemical Mixtures Program in Chicago, IL. The primary purpose of the meeting was to enable principal investigators to report the research status and accomplishments of ongoing complex chemical mixture studies supported by OHER. To help focus future research directions round table discussions were conducted.

  1. Effects of Chemically Modified Messenger RNA on Protein Expression.

    PubMed

    Li, Bin; Luo, Xiao; Dong, Yizhou

    2016-03-16

    Chemically modified nucleotides play significant roles in the effectiveness of mRNA translation. Here, we describe the synthesis of two sets of chemically modified mRNAs [encoding firefly Luciferase (FLuc) and enhanced green fluorescent protein (eGFP), respectively], evaluation of protein expression, and correlation analysis of expression level under various conditions. The results indicate that chemical modifications of mRNAs are able to significantly improve protein expression, which is dependent on cell types and coding sequences. Moreover, eGFP mRNAs with N1-methylpseudouridine (me(1)ψ), 5-methoxyuridine (5moU), and pseudouridine (ψ) modifications ranked top three in cell lines tested. Interestingly, 5moU-modified eGFP mRNA was more stable than other eGFP mRNAs. Consequently, me(1)ψ, 5moU, and ψ are promising nucleotides for chemical modification of mRNAs. PMID:26906521

  2. Effects of extracellular calcium and of light adaptation on the response to dim light in honey bee drone photoreceptors.

    PubMed Central

    Raggenbass, M

    1983-01-01

    Light responses in honey bee drone photoreceptors were recorded with intracellular micro-electrodes in superfused slices of retina. The effects of changes in extracellular calcium on the size and the shape of the response to dim light were studied and compared with the effects of light adaptation. Dim light stimuli were used so that the amplitude of the response was linearly related to the number of the photons absorbed, the effects of voltage-dependent mechanisms were negligible and no detectable light adaptation was produced by the stimulus. Lowering the extracellular calcium concentration increased the amplitude and the duration of the response. Raising the extracellular calcium concentration produced the opposite effects. Changing the extracellular calcium concentration modified the response without altering either the linearity of the intensity--response relation or the resting membrane potential in the dark. Light adaptation decreased the amplitude and the duration of the response in a manner that could be quantitatively simulated, in the same photoreceptors, by an increase in the extracellular calcium concentration. Changing the extracellular calcium concentration, or light-adapting the preparation, modified the response without altering its early depolarizing phase. Lowering external calcium either did not affect, or slightly increased, the maximum rate of the light-induced depolarization; raising external calcium, or light-adapting the preparation, either did not affect, or slightly decreased, the maximum rate of the light-induced depolarization. The experimental data can be quantitatively described by a mathematical model with the basic assumption that calcium acts in the process of light adaptation by decreasing the mean open time of the light-activated channels. PMID:6655592

  3. Chemical characteristics and light-absorbing property of water-soluble organic carbon in Beijing: Biomass burning contributions

    NASA Astrophysics Data System (ADS)

    Yan, Caiqing; Zheng, Mei; Sullivan, Amy P.; Bosch, Carme; Desyaterik, Yury; Andersson, August; Li, Xiaoying; Guo, Xiaoshuang; Zhou, Tian; Gustafsson, Örjan; Collett, Jeffrey L.

    2015-11-01

    Emissions from biomass burning contribute significantly to water-soluble organic carbon (WSOC) and light-absorbing organic carbon (brown carbon). Ambient atmospheric samples were collected at an urban site in Beijing during winter and summer, along with source samples from residential crop straw burning. Carbonaceous aerosol species, including organic carbon (OC), elemental carbon (EC), WSOC and multiple saccharides as well as water-soluble potassium (K+) in PM2.5 (fine particulate matter with size less than 2.5 μm) were measured. Chemical signatures of atmospheric aerosols in Beijing during winter and summer days with significant biomass burning influence were identified. Meanwhile, light absorption by WSOC was measured and quantitatively compared to EC at ground level. The results from this study indicated that levoglucosan exhibited consistently high concentrations (209 ± 145 ng m-3) in winter. Ratios of levoglucosan/mannosan (L/M) and levoglucosan/galacosan (L/G) indicated that residential biofuel use is an important source of biomass burning aerosol in winter in Beijing. Light absorption coefficient per unit ambient WSOC mass calculated at 365 nm is approximately 1.54 ± 0.16 m2 g-1 in winter and 0.73 ± 0.15 m2 g-1 in summer. Biomass burning derived WSOC accounted for 23 ± 7% and 16 ± 7% of total WSOC mass, and contributed to 17 ± 4% and 19 ± 5% of total WSOC light absorption in winter and summer, respectively. It is noteworthy that, up to 30% of total WSOC light absorption was attributed to biomass burning in significant biomass-burning-impacted summer day. Near-surface light absorption (over the range 300-400 nm) by WSOC was about ∼40% of that by EC in winter and ∼25% in summer.

  4. Radiation chemical effects of X-rays on liquids

    SciTech Connect

    Holroyd, R.A.; Preses, J.M.

    1998-11-01

    This review describes some of the chemical changes induced by photoelectrons which are released in liquids when X-rays are absorbed. Both experimental studies and theory are discussed. In part 1, the basic processes occurring upon absorption of X-rays are described. Parts 2 and 3 deal with hydrocarbon liquids; in part 2 the ion yields, including effects at K-edges, and in part 3, the yields of excited states. Part 4 discusses chemical effects of X-rays in aqueous solutions. The authors end with a summary of future needs and directions.

  5. Photo-oxidation effects of light-emitting porous Si

    NASA Astrophysics Data System (ADS)

    Tamura, Tomoyuki; Adachi, Sadao

    2009-06-01

    The effects of light illumination on porous silicon (PSi) properties have been studied using photoluminescence (PL), PL excitation (PLE), and x-ray photoelectron spectroscopy (XPS) measurements. The PL spectrum evolution in PSi sample under light illumination at various wavelengths indicates that the photo-oxidation occurs and causes a decrease in its intensity with increasing illumination time t. The decrease in the PL intensity IPL can be written as logarithmic expression, namely, the Elovich equation IPL∝-α ln t, where α is the quenching rate of the PL intensity associated with the native oxide growth. The α value is dependent on the illuminated photon energy Epo in a manner α =0.050Epo. Each PL spectrum can be deconvoluted into four Gaussian peaks. The higher the PL peak energy, the larger its photo-oxidation-induced blueshift. This fact and XPS results support that the light emission in a porous sample is due to the quantum-size effect, i.e., relaxation of the momentum conservation at and above the indirect absorption edge (supra-indirect-gap emission). The PLE spectra suggest that the surface hydrogen termination should influence the highly excited carrier dynamics in nanocrystalline PSi materials.

  6. The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching.

    PubMed

    Zhong, Hao; Guo, Anran; Guo, Guohui; Li, Wei; Jiang, Yadong

    2016-12-01

    We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm. Silicon nanocone arrays can be created using MCE treatment. These modified surfaces show higher light absorptance in the near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the variations in the absorption spectra of the nanostructured black silicon with different etching processes are obtained. The maximum light absorptance increases significantly up to 95 % in the wavelength range of 400 to 2500 nm. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has potential application in near-infrared photoelectronic detectors. PMID:27368764

  7. The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching

    NASA Astrophysics Data System (ADS)

    Zhong, Hao; Guo, Anran; Guo, Guohui; Li, Wei; Jiang, Yadong

    2016-07-01

    We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm. Silicon nanocone arrays can be created using MCE treatment. These modified surfaces show higher light absorptance in the near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the variations in the absorption spectra of the nanostructured black silicon with different etching processes are obtained. The maximum light absorptance increases significantly up to 95 % in the wavelength range of 400 to 2500 nm. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has potential application in near-infrared photoelectronic detectors.

  8. Exhaust emissions from gasoline-fuelled light duty vehicles operated in different driving conditions: A chemical and biological characterization

    NASA Astrophysics Data System (ADS)

    Westerholm, Roger; Almén, Jacob; Li, Hang; Rannug, Ulf; Rosén, Åke

    Chemical analysis and mutagenicity tests on Salmonella typtimurium strains TA 98 and TA 100 (Ames test) of exhaust emissions from five passengers vehicles, with or without a three-way catalyst, have been carried out to obtain emission factors and to characterize exhaust emissions. Both constant cruising speeds and transient driving conditions were investigated, regulated CO, HC, NO x and particulates, as well as unregulated pollutants, were analysed. The following unregulated pollutants were measured: particle-associated polycyclic aromatic hydrocarbons (PAH), 1-nitropyrene, light aromatics and light oxygenates. In total, 39 individual compounds were assayed. Emissions from catalyst-equipped vehicles showed a dramatic decrease compared with those from the vehicle without a catalyst. An emission dependency of both regulated and unregulated pollutants and biological activity on driving conditions were determined. An increased emission of PAH, 1-nitropyrene, particulates and mutagenic activity was found with a higher cruising speed.

  9. Synthesis of Graphene Films by Chemical Vapor Deposition for Transparent Conducting Electrodes of GaN Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Jo, Gunho; Choe, Minhyeok; Cho, Chu-Young; Kim, Jin Ho; Park, Woojin; Lee, Sangchul; Park, Seong-Ju; Hong, Byung Hee; Kahng, Yung Ho; Lee, Takhee

    2011-12-01

    This work demonstrales large-scale simultaneous fabrication of patterned graphene-based GaN light-emitting diodes (LEDs). Graphene sheets were synthesized using a chemical vapor deposition (CVD) technique on nickel films and showed typical CVD-synthesized film properties, possessing a sheet resistance of ˜605 Ω/⃞ with a transparency of more than 85% in the 400-800 nm wavelength range, and was applied as transparent condueting electrodes of GaN-based blue LHDs, The light output performance of GaN LEDs with graphene electrodes was comparable to that of conventional ITO-electrode LEDs over the range of input current up to 150 mA.

  10. Light-enhanced chemical whitening of teeth: new in vitro investigation

    NASA Astrophysics Data System (ADS)

    Todorovska, R.; Dimitrov, S.; Pavlova, P.; Todorov, G.

    2007-03-01

    We report new results on the light enhanced teeth whitening obtained in a research collaboration financed by the Medical Science Council of the Medical University of Sofia. The project is an extension of previous research and its basic goal is to develop new teeth bleaching substances and procedures, in which the activators are diode lamps (LED).

  11. Cognitive effects of endocrine-disrupting chemicals in animals.

    PubMed Central

    Schantz, S L; Widholm, J J

    2001-01-01

    A large number of chemical pollutants including phthalates, alkylphenolic compounds, polychlorinated biphenyls and polychlorinated dibenzodioxins, organochlorine pesticides, bisphenol A, and metals including lead, mercury, and cadmium have the ability to disrupt endocrine function in animals. Some of these same chemicals have been shown to alter cognitive function in animals and humans. Because hormonally mediated events play a central role in central nervous system development and function, a number of researchers have speculated that the changes in cognitive function are mediated by the endocrine-like actions of these chemicals. In this paper we review the evidence that cognitive effects of chemicals classified as environmental endocrine disruptors are mediated by changes in hormonal function. We begin by briefly reviewing the role of gonadal steroids, thyroid hormones, and glucocorticoids in brain development and brain function. We then review the endocrine changes and cognitive effects that have been reported for selected endocrine-disrupting chemicals, discuss the evidence for causal relationships between endocrine disruption and cognitive effects, and suggest directions for future research. PMID:11748026

  12. Effect of recycled light in two-beam interferometry

    SciTech Connect

    Cavagnero, Giovanni; Mana, Giovanni; Massa, Enrico

    2005-05-15

    We developed a laser interferometer allowing parts per million resolution to be achieved in fringe division for the measurement of the Si (220) lattice spacing by combined x-ray and optical interferometry. With the aim of obtaining 10{sup -9} measurement uncertainty, we pursued the study of a troublesome noise in interferometer operation and eventually identified its origin in a minute interferometer optical feedback. We investigated mathematically the feedback effect and verified predictions experimentally. Imperfect isolation and light recycling having been identified and subsequently experimentally proved, we took remedial steps in order to improve measurement capabilities. This investigation has brought into light and has made it possible to quantify an interferometer noise up to now overlooked.

  13. Slow-light enhanced absorption for bio-chemical sensing applications: potential of low-contrast lossy materials

    NASA Astrophysics Data System (ADS)

    Pedersen, J.; Xiao, S.; Mortensen, N. A.

    2008-02-01

    Slow-light enhanced absorption in liquid-infiltrated photonic crystals has recently been proposed as a route to compensate for the reduced optical path in typical lab-on-a-chip systems for bio-chemical sensing applications. A simple perturbative expression has been applied to ideal structures composed of lossless dielectrics. In this work we study the enhancement in structures composed of lossy dielectrics such as a polymer. For this particular sensing application we find that the material loss has an unexpected limited drawback and surprisingly, it may even add to increase the bandwidth for low-index contrast systems such as polymer devices.

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

    NASA Astrophysics Data System (ADS)

    Cope, K. R.; Bugbee, B.

    2011-12-01

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

  15. High Color-Purity Green, Orange, and Red Light-Emitting Didoes Based on Chemically Functionalized Graphene Quantum Dots.

    PubMed

    Kwon, Woosung; Kim, Young-Hoon; Kim, Ji-Hee; Lee, Taehyung; Do, Sungan; Park, Yoonsang; Jeong, Mun Seok; Lee, Tae-Woo; Rhee, Shi-Woo

    2016-01-01

    Chemically derived graphene quantum dots (GQDs) to date have showed very broad emission linewidth due to many kinds of chemical bondings with different energy levels, which significantly degrades the color purity and color tunability. Here, we show that use of aniline derivatives to chemically functionalize GQDs generates new extrinsic energy levels that lead to photoluminescence of very narrow linewidths. We use transient absorption and time-resolved photoluminescence spectroscopies to study the electronic structures and related electronic transitions of our GQDs, which reveals that their underlying carrier dynamics is strongly related to the chemical properties of aniline derivatives. Using these functionalized GQDs as lumophores, we fabricate light-emitting didoes (LEDs) that exhibit green, orange, and red electroluminescence that has high color purity. The maximum current efficiency of 3.47 cd A(-1) and external quantum efficiency of 1.28% are recorded with our LEDs; these are the highest values ever reported for LEDs based on carbon-nanoparticle phosphors. This functionalization of GQDs with aniline derivatives represents a new method to fabricate LEDs that produce natural color. PMID:27048887

  16. High Color-Purity Green, Orange, and Red Light-Emitting Didoes Based on Chemically Functionalized Graphene Quantum Dots

    PubMed Central

    Kwon, Woosung; Kim, Young-Hoon; Kim, Ji-Hee; Lee, Taehyung; Do, Sungan; Park, Yoonsang; Jeong, Mun Seok; Lee, Tae-Woo; Rhee, Shi-Woo

    2016-01-01

    Chemically derived graphene quantum dots (GQDs) to date have showed very broad emission linewidth due to many kinds of chemical bondings with different energy levels, which significantly degrades the color purity and color tunability. Here, we show that use of aniline derivatives to chemically functionalize GQDs generates new extrinsic energy levels that lead to photoluminescence of very narrow linewidths. We use transient absorption and time-resolved photoluminescence spectroscopies to study the electronic structures and related electronic transitions of our GQDs, which reveals that their underlying carrier dynamics is strongly related to the chemical properties of aniline derivatives. Using these functionalized GQDs as lumophores, we fabricate light-emitting didoes (LEDs) that exhibit green, orange, and red electroluminescence that has high color purity. The maximum current efficiency of 3.47 cd A−1 and external quantum efficiency of 1.28% are recorded with our LEDs; these are the highest values ever reported for LEDs based on carbon-nanoparticle phosphors. This functionalization of GQDs with aniline derivatives represents a new method to fabricate LEDs that produce natural color. PMID:27048887

  17. High Color-Purity Green, Orange, and Red Light-Emitting Didoes Based on Chemically Functionalized Graphene Quantum Dots

    NASA Astrophysics Data System (ADS)

    Kwon, Woosung; Kim, Young-Hoon; Kim, Ji-Hee; Lee, Taehyung; Do, Sungan; Park, Yoonsang; Jeong, Mun Seok; Lee, Tae-Woo; Rhee, Shi-Woo

    2016-04-01

    Chemically derived graphene quantum dots (GQDs) to date have showed very broad emission linewidth due to many kinds of chemical bondings with different energy levels, which significantly degrades the color purity and color tunability. Here, we show that use of aniline derivatives to chemically functionalize GQDs generates new extrinsic energy levels that lead to photoluminescence of very narrow linewidths. We use transient absorption and time-resolved photoluminescence spectroscopies to study the electronic structures and related electronic transitions of our GQDs, which reveals that their underlying carrier dynamics is strongly related to the chemical properties of aniline derivatives. Using these functionalized GQDs as lumophores, we fabricate light-emitting didoes (LEDs) that exhibit green, orange, and red electroluminescence that has high color purity. The maximum current efficiency of 3.47 cd A‑1 and external quantum efficiency of 1.28% are recorded with our LEDs; these are the highest values ever reported for LEDs based on carbon-nanoparticle phosphors. This functionalization of GQDs with aniline derivatives represents a new method to fabricate LEDs that produce natural color.

  18. Chemical Hair Relaxers Have Adverse Effects a Myth or Reality

    PubMed Central

    Shetty, Vinma H; Shetty, Narendra J; Nair, Dhanya Gopinath

    2013-01-01

    Context: Hair plays an important role in one's personality and builds confidence. Now-a-days, chemical hair relaxers are used very commonly in the society. We document the adverse effects reported by the sample that have used any one of the professional chemical hair relaxers. Aim: To study the adverse effects reported by the sample who underwent repeated chemical hair relaxing. Settings and Design: Cross-sectional questionnaire based study done on a sample taken from a medical college and hospital campus in Mangalore. Materials and Methods: The sample was restricted to females and to those who underwent it more than once. A questionnaire was given to a sample of 90, which matched our criteria. Statistical Analysis: SPSS software 17. Results: Adverse effects reported by the sample after undergoing the procedure were found to be a high 95.56%, out of which the following are the common adverse effects reported; frizzy hair in 67%, dandruff in 61%, hair loss in 47%, thinning and weakening of hair in 40%, greying of hair 22%, and split ends in only 17%. Conclusions: Very few studies have been conducted on the adverse effects of hair straightening products in India. From our study, it can be stated that most of the samples had adverse effects, which was as high as 95.56%. Hence from the details elicited from this study, we can conclude that, usage of chemical hair relaxers does cause adverse effects and is “not a myth.” Thus, it is necessary to make available a less harmful chemical hair relaxer to the society. PMID:23960393

  19. Effects of selenium and light wavelengths on liquid culture of Cordyceps militaris Link.

    PubMed

    Dong, J Z; Liu, M R; Lei, C; Zheng, X J; Wang, Y

    2012-04-01

    To investigate the effects of selenium and light wavelengths on the growth of liquid-cultured Cordyceps militaris and the main active components' accumulation, culture conditions as selenium selenite concentrations and light of different wavelengths were studied. The results are: adenosine accumulation proved to be significantly selenium dependent (R(2) = 0.9403) and cordycepin contents were determined to be not significantly selenium dependent (R(2) = 0.3845) but significantly enhanced by selenium except for 20 ppm; there were significant differences in cordycepin contents, adenosine contents, and mycelium growth caused by light wavelengths: cordycepin, blue light > pink light > daylight, darkness, red light; adenosine, red light > pink light, darkness, daylight, blue light; and mycelium growth, red light > pink light, darkness, daylight > blue light. In conclusion, light wavelength had a significant influence on production of mycelia, adenosine, and cordycepin, so lightening wavelength should be changed according to target products in the liquid culture of C. militaris. PMID:22434354

  20. Chemical contaminants in feedlot wastes: concentrations, effects and attenuation.

    PubMed

    Khan, S J; Roser, D J; Davies, C M; Peters, G M; Stuetz, R M; Tucker, R; Ashbolt, N J

    2008-08-01

    Commercial feedlots for beef cattle finishing are potential sources of a range of trace chemicals which have human health or environmental significance. To ensure adequate protection of human and environmental health from exposure to these chemicals, the application of effective manure and effluent management practices is warranted. The Australian meat and livestock industry has adopted a proactive approach to the identification of best management practices. Accordingly, this review was undertaken to identify key chemical species that may require consideration in the development of guidelines for feedlot manure and effluent management practices in Australia. Important classes of trace chemicals identified include steroidal hormones, antibiotics, ectoparasiticides, mycotoxins, heavy metals and dioxins. These are described in terms of their likely sources, expected concentrations and public health or environmental significance based on international data and research. Androgenic hormones such as testosterone and trenbolone are significantly active in feedlot wastes, but they are poorly understood in terms of fate and environmental implications. The careful management of residues of antibiotics including virginiamycin, tylosin and oxytetracycline appears prudent in terms of minimising the risk of potential public health impacts from resistant strains of bacteria. Good management of ectoparasiticides including synthetic pyrethroids, macrocyclic lactones, fluazuron, and amitraz is important for the prevention of potential ecological implications, particularly towards dung beetles. Very few of these individual chemical contaminants have been thoroughly investigated in terms of concentrations, effects and attenuation in Australian feedlot wastes. PMID:18055014

  1. Effect of light and sweeteners on color in an amaretto-type liqueur.

    PubMed

    Castañeda-Olivares, F; Pless, R C; González-Jasso, E

    2010-01-01

    Studies on the color loss in an amaretto-type liqueur under controlled light conditions showed a clear dependence of the decoloration rate on the light intensity, and complete color stability in the absence of light. The principal sweetener used in the preparation of the liqueur strongly affected the rate of color loss under irradiation, color stability being much greater for the formulations containing sucrose or no added sweetener instead of fructose 42. These differences were more pronounced in experiments conducted with chemically well-defined mixtures that contained either of the 2 azo dyes used in the coloration of the amaretto, tartrazine, and Allura Red, and various alternative sweeteners, in 28% (v/v) ethanol solution: D-fructose and, to a lesser extent, D-glucose, at concentrations of 14% (w/v), were effective in bringing about photodecoloration, while no color loss was detected in the presence of sucrose, or in the absence of any added sugar. The results are interpreted in terms of a redox reaction of reducing sugars with the diarylazo compounds, the function of the light being the conversion of the azo compound from the predominant trans configuration to the cis configuration, which on geometric grounds lends itself better to a concerted, cyclical redox reaction with the reducing sugar. PMID:21535589

  2. Effect of light polarization on holographic recording in glassy azocompounds and chalcogenides

    NASA Astrophysics Data System (ADS)

    Ozols, Andris; Kokars, Valdis; Augustovs, Peteris; Uiska, Ilze; Traskovskis, Kaspars; Saharov, Dmitry

    2011-04-01

    Light polarization effects on a holographic grating recording in a glassy chalcogenide a-As40S15Se45 film has been experimentally studied and compared with previously studied glassy molecular azobenzene film 8a at 633, using s - s,p - p, CE-1 and CE-2 circular-elliptic recording-beam polarizations (differing by light electric field rotation directions). The azocompound exhibited much higher self-diffraction efficiency (SDE) and diffraction efficiency whereas chalcogenide was more sensitive. Their recording efficiency polarization dependences also were different. SDE up to 45% was achieved in 8a with p - p and up to 2.6% in a-As40S15Se45 with CE-2 polarized recording beams. The polarization changes in the diffraction process were studied as well in these and other materials ( 11, 16, 19 and a-As2S3 film, LiTaO3:Fe crystal). It was found that light polarization changes in the process of diffraction from gratings recorded vectorially by s- p polarizations depended on chemical composition, wavelength, and exposure time. Vector gratings with SDE up to 25% were recorded in 8a, rotating a linear polarization by 90°. No light polarization changes were found in azobenzene 19 and chalcogenide films and in LiTaO3:Fe crystal, thus showing a vector recording of scalar holograms. The recording mechanisms in azocompounds and chalcogenides are discussed and compared.

  3. Effect of light polarization on holographic recording in glassy azocompounds and chalcogenides

    NASA Astrophysics Data System (ADS)

    Ozols, Andris; Kokars, Valdis; Augustovs, Peteris; Uiska, Ilze; Traskovskis, Kaspars; Saharov, Dmitry

    2011-04-01

    Light polarization effects on a holographic grating recording in a glassy chalcogenide a-As40S15Se45 film has been experimentally studied and compared with previously studied glassy molecular azobenzene film 8a at 633, using s - s,p - p, CE-1 and CE-2 circular-elliptic recording-beam polarizations (differing by light electric field rotation directions). The azocompound exhibited much higher self-diffraction efficiency (SDE) and diffraction efficiency whereas chalcogenide was more sensitive. Their recording efficiency polarization dependences also were different. SDE up to 45% was achieved in 8a with p - p and up to 2.6% in a-As40S15Se45 with CE-2 polarized recording beams. The polarization changes in the diffraction process were studied as well in these and other materials (11, 16, 19 and a-As2S3 film, LiTaO3:Fe crystal). It was found that light polarization changes in the process of diffraction from gratings recorded vectorially by s-p polarizations depended on chemical composition, wavelength, and exposure time. Vector gratings with SDE up to 25% were recorded in 8a, rotating a linear polarization by 90°. No light polarization changes were found in azobenzene 19 and chalcogenide films and in LiTaO3:Fe crystal, thus showing a vector recording of scalar holograms. The recording mechanisms in azocompounds and chalcogenides are discussed and compared.

  4. CHEMICAL MIXTURES AND HEALTH EFFECTS AT SUPERFUND SITES

    EPA Science Inventory

    Between 1991 and 1993, EPA's Office of Research and Development conducted a small health effects research program dedicated to the problem of chemical mixtures at Superfund sites. This paper summarizes key findings from the program. The studies covered a wide range of endpoints, ...

  5. EFFECTIVE RISK MANAGEMENT OF ENDOCRINE DISRUPTING CHEMICALS WORKSHOP NEWMEDIA CD

    EPA Science Inventory

    This product is a CD-ROM version of the workshop, Effective Risk Management of Endocrine Disrupting Chemicals, held in January 2002, in Cincinnati, Ohio. The goal of this workshop was to introduce the science and engineering behind managing the potential risk of suspected endocri...

  6. Chemical release and radiation effects experiment advanced planning and coordination

    NASA Technical Reports Server (NTRS)

    Vaughan, William W.; Alzmann, Melanie

    1991-01-01

    The efforts conducted to provide assessments and planning support for the Chemical Release and Radiation Effects Satellite (CRRES) Experiments are summarized. Included are activities regarding scientific working group and workshop development including the preparation of descriptive information on the CRRES Project.

  7. Environmental chemical mixtures: Assessing ecological exposure and effects in streams

    EPA Science Inventory

    This product is a USGS fact sheet that describes a collaborative effort between USGS and US EPA to characterize exposures to chemical mixtures and associated biological effects for a diverse range of US streams representing varying watershed size, land-use patterns, and ecotypes.

  8. Seeing Chemistry through Sound: A Submersible Audible Light Sensor for Observing Chemical Reactions for Students Who Are Blind or Visually Impaired

    ERIC Educational Resources Information Center

    Supalo, Cary A.; Kreuter, Rodney A.; Musser, Aaron; Han, Josh; Briody, Erika; McArtor, Chip; Gregory, Kyle; Mallouk, Thomas E.

    2006-01-01

    In order to enable students who are blind and visually impaired to observe chemical changes in solutions, a hand-held device was designed to output light intensity as an audible tone. The submersible audible light sensor (SALS) creates an audio signal by which one can observe reactions in a solution in real time, using standard laboratory…

  9. Modeling the Role of Selected Light Nonmethane Hydrocarbons on the Chemical Composition of Natural and Perturbed Troposphere

    NASA Astrophysics Data System (ADS)

    Gupta, Mohan Lal

    The original Oslo 2-dimensional global tropospheric photochemical model is modified by extending its vertical domain to 24.5 km with new transport coefficients to deduce the annual global source strengths of parent hydrocarbons (C-1 to C-3, or LHCs) and to study the role of photochemistry of these hydrocarbons and isoprene (rm C _5H_8) on the chemical composition of natural and perturbed troposphere. Model transport features are studied by comparing simulated atmospheric distributions and trends of CFC-11, CFC-12 and ^{85}Kr with corresponding long term observations. Four different photochemical schemes PC-1, PC -2, PC-3, and PC-5, that include C-1, C-2, C-3 hydrocarbons and rm C_5H_8 respectively, are developed. OH radical distributions calculated using these schemes and averaged surface observation data of LHCs as their respective lower boundary conditions are validated by comparing simulated atmospheric distribution and trends of rm CH_3CCl_3 with ALE/GAGE observations. Annual steady state source strengths of LHCs and rm C_2Cl _4 are calculated from their surface observations and above stated OH distributions. Comparison of modeled concentrations of C-2 and C-3 hydrocarbons in the lowest model layer with their corresponding observations shows that the sources of these species are seasonal in nature. The effects of photochemistry of light nonmethane hydrocarbons (NMHCs) on distributions of selected tropospheric species and ratio distributions of key species and on the budgets of O_3, CO, NOx and HNO _3 are also evaluated. Simulations of multiple changes in individual source strengths of NOx, CH_4, CO, NMHCs suggest that per molecule injected, NOx from aircraft emissions is the most efficient, the magnitude of which decreases with increase in emissions, in changing the global averaged O_3 concentration. Among NMHCs, changes in propane and ethane emissions are the most effective in changing the global average O _3 concentration and steady state lifetime of CH_4

  10. Techniques for Accurate Sizing of Gold Nanoparticles Using Dynamic Light Scattering with Particular Application to Chemical and Biological Sensing Based on Aggregate Formation.

    PubMed

    Zheng, Tianyu; Bott, Steven; Huo, Qun

    2016-08-24

    Gold nanoparticles (AuNPs) have found broad applications in chemical and biological sensing, catalysis, biomolecular imaging, in vitro diagnostics, cancer therapy, and many other areas. Dynamic light scattering (DLS) is an analytical tool used routinely for nanoparticle size measurement and analysis. Due to its relatively low cost and ease of operation in comparison to other more sophisticated techniques, DLS is the primary choice of instrumentation for analyzing the size and size distribution of nanoparticle suspensions. However, many DLS users are unfamiliar with the principles behind the DLS measurement and are unware of some of the intrinsic limitations as well as the unique capabilities of this technique. The lack of sufficient understanding of DLS often leads to inappropriate experimental design and misinterpretation of the data. In this study, we performed DLS analyses on a series of citrate-stabilized AuNPs with diameters ranging from 10 to 100 nm. Our study shows that the measured hydrodynamic diameters of the AuNPs can vary significantly with concentration and incident laser power. The scattered light intensity of the AuNPs has a nearly sixth order power law increase with diameter, and the enormous scattered light intensity of AuNPs with diameters around or exceeding 80 nm causes a substantial multiple scattering effect in conventional DLS instruments. The effect leads to significant errors in the reported average hydrodynamic diameter of the AuNPs when the measurements are analyzed in the conventional way, without accounting for the multiple scattering. We present here some useful methods to obtain the accurate hydrodynamic size of the AuNPs using DLS. We also demonstrate and explain an extremely powerful aspect of DLS-its exceptional sensitivity in detecting gold nanoparticle aggregate formation, and the use of this unique capability for chemical and biological sensing applications. PMID:27472008

  11. Integrated Light Chemical Abundance Analyses of 7 M31 Outer Halo Globular Clusters from the Pan-Andromeda Archaeological Survey

    NASA Astrophysics Data System (ADS)

    Sakari, Charli; Venn, Kim; Mackey, Dougal; Shetrone, Matthew D.; Dotter, Aaron L.; Wallerstein, George

    2015-01-01

    Detailed chemical abundances of globular clusters provide insight into the formation and evolution of galaxies and their globular cluster systems. This talk presents detailed chemical abundances for seven M31 outer halo globular clusters (with projected radii greater than 30 kpc), as derived from high resolution integrated light spectra. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS). The integrated abundances show that 4 of these clusters are metal-poor ([Fe/H] < -1.5) while the other 3 are more metal-rich. The most metal-poor globular clusters are α-enhanced, though 3 of the 4 are possibly less α-enhanced than MW stars (at the 1σ level). Other chemical abundance ratios ([Ba/Eu], [Eu/Ca], and [Ni/Fe]) are consistent with origins in low mass dwarf galaxies (similar to Fornax). The most metal-rich cluster ([Fe/H] ~ -1) stands out as being chemically distinct from Milky Way field stars of the same metallicity---its chemical abundance ratios agree best with the stars and clusters in the Large Magellanic Cloud (LMC) and the Sagittarius dwarf spheroidal (Sgr) than with the Milky Way field stars. The other metal-rich clusters, H10 and H23, look similar to the LMC and Milky Way field stars in all abundance ratios. These results indicate that M31's outer halo is being at least partially built up by the accretion of dwarf satellites, in agreement with previous observations.

  12. The effects of environmental chemicals on renal function

    PubMed Central

    Kataria, Anglina; Trasande, Leonardo; Trachtman, Howard

    2015-01-01

    The global incidence of chronic kidney disease (CKD) is increasing among individuals of all ages. Despite advances in proteomics, genomics and metabolomics, there remains a lack of safe and effective drugs to reverse or stabilize renal function in patients with glomerular or tubulointerstitial causes of CKD. Consequently, modifiable risk factors that are associated with a progressive decline in kidney function need to be identified. Numerous reports have documented the adverse effects that occur in response to graded exposure to a wide range of environmental chemicals. This Review summarizes the effects of such chemicals on four aspects of cardiorenal function: albuminuria, glomerular filtration rate, blood pressure and serum uric acid concentration. We focus on compounds that individuals are likely to be exposed to as a consequence of normal consumer activities or medical treatment, namely phthalates, bisphenol A, polyfluorinated alkyl acids, dioxins and furans, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. Environmental exposure to these chemicals during everyday life could have adverse consequences on renal function and might contribute to progressive cumulative renal injury over a lifetime. Regulatory efforts should be made to limit individual exposure to environmental chemicals in an attempt to reduce the incidence of cardiorenal disease. PMID:26100504

  13. The effects of environmental chemicals on renal function.

    PubMed

    Kataria, Anglina; Trasande, Leonardo; Trachtman, Howard

    2015-10-01

    The global incidence of chronic kidney disease (CKD) is increasing among individuals of all ages. Despite advances in proteomics, genomics and metabolomics, there remains a lack of safe and effective drugs to reverse or stabilize renal function in patients with glomerular or tubulointerstitial causes of CKD. Consequently, modifiable risk factors that are associated with a progressive decline in kidney function need to be identified. Numerous reports have documented the adverse effects that occur in response to graded exposure to a wide range of environmental chemicals. This Review summarizes the effects of such chemicals on four aspects of cardiorenal function: albuminuria, glomerular filtration rate, blood pressure and serum uric acid concentration. We focus on compounds that individuals are likely to be exposed to as a consequence of normal consumer activities or medical treatment, namely phthalates, bisphenol A, polyfluorinated alkyl acids, dioxins and furans, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. Environmental exposure to these chemicals during everyday life could have adverse consequences on renal function and might contribute to progressive cumulative renal injury over a lifetime. Regulatory efforts should be made to limit individual exposure to environmental chemicals in an attempt to reduce the incidence of cardiorenal disease. PMID:26100504

  14. Adiabatic separatrix crossing theory for heavy-light-heavy chemical reactions in three dimensions

    NASA Astrophysics Data System (ADS)

    Skodje, Rex T.

    1991-11-01

    The beautifully regular dynamics observed for the collinear I+HI reaction appears to be largely irrelevant for the three-dimensional reaction. The pronounced oscillations in the collinear reaction probability and other variables are suppressed in three dimensions due to the extreme instability of the collinear dynamics in directions orthogonal to the collinear subspace. A new theory is formulated for the three-dimensional classical dynamics of heavy-light-heavy (HLH) reactions. This theory is based on three ideas. First, the fastest time scale motion can be adiabatically eliminated with high accuracy. The fast motion corresponds to diatomic vibration in the asymptotic channels and to asymmetric stretch motion in the strong collision region. A composite set of ``α'' and ``β'' channel Jacobi coordinates properly captures the correct separation of time scales. Second, the reactive separatrix can be easily defined within the adiabatic approximation and is crucial in modeling the reactive dynamics. The separatrix is the boundary in phase space between the trajectories where the light atom is dynamically bound to one of the heavy atoms and those trajectories where the light atom is exchanging back and forth between the two heavy atoms. Third, trajectories which cross the separatrix behave statistically in three dimensions. For the I+HI reaction with J=0, it is found that the reaction probability is very accurately modeled by PR= (1)/(2) Px, where Px is the probability for trajectories to cross the separatrix in the adiabatic approximation. Numerical simulations on the I+HI reaction strongly support a statistical adiabatic separatrix crossing theory and suggest widespread chaotic scattering for reactive orbits.

  15. Chemical composition of aerosol particles and light extinction apportionment before and during the heating season in Beijing, China

    NASA Astrophysics Data System (ADS)

    Wang, Qingqing; Sun, Yele; Jiang, Qi; Du, Wei; Sun, Chengzhu; Fu, Pingqing; Wang, Zifa

    2015-12-01

    Despite extensive efforts into characterization of the sources and formation mechanisms of severe haze pollution in the megacity of Beijing, the response of aerosol composition and optical properties to coal combustion emissions in the heating season remain poorly understood. Here we conducted a 3 month real-time measurement of submicron aerosol (PM1) composition by an Aerosol Chemical Speciation Monitor and particle light extinction by a Cavity Attenuated Phase Shift extinction monitor in Beijing, China, from 1 October to 31 December 2012. The average (±σ) PM1 concentration was 82.4 (±73.1) µg/m3 during the heating period (HP, 15 November to 31 December), which was nearly 50% higher than that before HP (1 October to 14 November). While nitrate and secondary organic aerosol (SOA) showed relatively small changes, organics, sulfate, and chloride were observed to have significant increases during HP, indicating the dominant impacts of coal combustion sources on these three species. The relative humidity-dependent composition further illustrated an important role of aqueous-phase processing for the sulfate enhancement during HP. We also observed great increases of hydrocarbon-like OA (HOA) and coal combustion OA (CCOA) during HP, which was attributed to higher emissions at lower temperatures and coal combustion emissions, respectively. The relationship between light extinction and chemical composition was investigated using a multiple linear regression model. Our results showed that the largest contributors to particle extinction were ammonium nitrate (32%) and ammonium sulfate (28%) before and during HP, respectively. In addition, the contributions of SOA and primary OA to particle light extinction were quantified. The results showed that the OA extinction was mainly caused by SOA before HP and by SOA and CCOA during HP, yet with small contributions from HOA and cooking aerosol for the entire study period. Our results elucidate substantial changes of aerosol

  16. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1990-07-01

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies of NO adsorption, reaction probing, study state rate measurement, and transient kinetic study. A better understanding of the role of additive on the synthesis reaction may allow us to sue chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas. (VC)

  17. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1990-07-01

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies of NO adsorption, reaction probing, study state rate measurement, and transient kinetic study. A better understanding of the role of additive on the synthesis reaction may allow us to use chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas.

  18. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1988-11-14

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies including temperature programmed desorption, infrared study of NO adsorption, reactive probing, steady state rate measurement, and transient kinetic study. A better understanding of the role of additive on the synthesis reaction may allow us to use chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas.

  19. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.; Balakos, M.W.

    1991-09-20

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies of NO adsorption, reaction probing, study state rate measurement, and transient kinetic study. A better understanding of the role of additives on the synthesis reaction may allow us to use chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas. 27 refs. 7 figs., 2 tabs.

  20. Effects of chemically contaminated sewage sludge on an aphid population

    SciTech Connect

    Culliney, T.W.; Pimentel, D.

    1986-12-01

    Survival and fecundity of green peach aphids, Myzus persicae, were markedly reduced when they were fed on collard plants grown in pots of soil treated with chemically contaminated sewage sludge, as compared to populations on potted plants grown in uncontaminated sludge or on fertilized soil (control). Calculated demographic parameters differed significantly between the contaminated sludge and uncontaminated sludge populations and between the contaminated sludge and control populations. No significant differences were detected between the uncontaminated sludge and control populations. The ecological effects on the aphids suggest that plant uptake and translocation of chemicals from the contaminated sludge affected aphid fitness through direct toxicity and/or reduced nutritional value of the plant. These results indicate that phytophagous insects may be affected by chemical contaminants in sewage sludge used in agriculture.

  1. Impact of light on organic solar cells: evolution of the chemical structure, morphology, and photophysical properties of the active layer

    NASA Astrophysics Data System (ADS)

    Rivaton, Agnès; Chambon, Sylvain; Manceau, Matthieu; Gardette, Jean-Luc; Firon, Muriel; Lemaître, Noëlla; Guillerez, Stéphane; Cros, Stéphane

    2008-04-01

    Organic photovoltaic represents an emerging technology thanks to its ability to give flexible, light weight and large-area devices, with low production cost by simple solution process or printing technologies. But these devices are known to exhibit low resistance to the combined action of sunlight, oxygen and water. This paper is focused on the behaviour of the active layer of the devices under illumination in the presence and absence of oxygen. The monitoring of the evolution of the chemical structure of MDMO-PPV submitted to accelerated artificial ageing permitted the elucidation of the mechanisms by which the polymer degrades. Extrapolation of the data to natural ageing suggested that, if well protected from oxygen (encapsulation), MDMO-PPV:PCBM based active layer is photochemically stable for several years in use conditions. In addition the charge transfer between the two materials was observed to remain efficient under exposure. The study of P3HT:PCBM blends allowed to point out the Achilles heel of P3HT towards the impact of light. In addition, P3HT:PCBM blends were shown to be much more stable under illumination than MDMO:PCBM blends. Preliminary results devoted to the AFM monitoring of the morphological modifications of P3HT:PCBM blends under the impact of light are also reported.

  2. Qualifying lighting remodelling in a Hungarian city based on light pollution effects

    NASA Astrophysics Data System (ADS)

    Kolláth, Z.; Dömény, A.; Kolláth, K.; Nagy, B.

    2016-09-01

    The public lighting system has been remodelled in several Hungarian cities. In some cases the majority of the old luminaries were fitted with high pressure sodium lamps and they were replaced with white LED lighting with a typical correlated colour temperature of about 4500 K. Therefore, these remodelling works provide a testbed for methods in measurements and modelling. We measured the luminance of the light domes of selected cities by DSLR photometry before and after the remodelling. Thanks to the full cut off design of the new lighting fixtures we obtained a slight decrease even in the blue part of the sky dome spectra of a tested city. However, we have to note that this positive change is the result of the bad geometry (large ULR) of the previous lighting system. Based on Monte Carlo radiative transfer calculations we provide a comparison of different indicators that can be used to qualify the remodelling, and to predict the possible changes in light pollution.

  3. Once the Light Touch to the Brain: Cytotoxic Effects of Low-Dose Gamma-Ray, Laser Light, and Visible Light on Rat Neuronal Cell Culture

    PubMed Central

    Cakir, Murteza; Colak, Abdullah; Calikoglu, Cagatay; Taspinar, Numan; Sagsoz, Mustafa Erdem; Kadioglu, Hakan Hadi; Hacimuftuoglu, Ahmet; Seven, Sabriye

    2016-01-01

    Objective: We aimed to evaluate the effects of gamma-ray, laser light, and visible light, which neurons are commonly exposed to during treatment of various cranial diseases, on the viability of neurons. Materials and Methods: Neuronal cell culture was prepared from the frontal cortex of 9 newborn rats. Cultured cells were irradiated with gamma-ray for 1–10 min by 152Eu, 241Am, and 132Ba isotopes, visible light for 1–160 min, and laser light for 0.2–2 seconds. The MTT tetrazolium reduction assay was used to assess the number of viable cells in the neuronal cell cultures. Wavelength dispersive X-ray fluorescence spectrometer was used to determine Na, K, and Ca levels in cellular fluid obtained from neuronal cell culture plaques. Results: Under low-dose radiation with 152Eu, 241Am, and 132Ba isotopes, cell viability insignificantly decreased with time (p>0.05). On the other hand, exposure to visible light produced statistically significant decrease in cell viability at both short- (1–10 min) and long-term (20–160 min). Cell viability did not change with 2 seconds of laser exposure. Na, K, and Ca levels significantly decreased with gamma-ray and visible light. The level of oxidative stress markers significantly changed with gamma-ray. Conclusion: In conclusion, while low dose gamma-ray has slight to moderate apoptotic effect in neuronal cell cultures by oxidative stress, long-term visible light induces remarkable apoptosis and cell death. Laser light has no significant effect on neurons. Further genetic studies are needed to clarify the chronic effect of visible light on neuronal development and functions. PMID:27551168

  4. Infrared light gated MoS₂ field effect transistor.

    PubMed

    Fang, Huajing; Lin, Ziyuan; Wang, Xinsheng; Tang, Chun-Yin; Chen, Yan; Zhang, Fan; Chai, Yang; Li, Qiang; Yan, Qingfeng; Chan, H L W; Dai, Ji-Yan

    2015-12-14

    Molybdenum disulfide (MoS₂) as a promising 2D material has attracted extensive attentions due to its unique physical, optical and electrical properties. In this work, we demonstrate an infrared (IR) light gated MoS₂ transistor through a device composed of MoS₂ monolayer and a ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O₃-PbTiO₃ (PMN-PT). With a monolayer MoS₂ onto the top surface of (111) PMN-PT crystal, the drain current of MoS₂ channel can be modulated with infrared illumination and this modulation process is reversible. Thus, the transistor can work as a new kind of IR photodetector with a high IR responsivity of 114%/Wcm⁻². The IR response of MoS₂ transistor is attributed to the polarization change of PMN-PT single crystal induced by the pyroelectric effect which results in a field effect. Our result promises the application of MoS₂ 2D material in infrared optoelectronic devices. Combining with the intrinsic photocurrent feature of MoS₂ in the visible range, the MoS₂ on ferroelectric single crystal may be sensitive to a broadband wavelength of light. PMID:26698982

  5. Photo and Chemical Reduction of Copper onto Anatase-Type TiO2 Nanoparticles with Enhanced Surface Hydroxyl Groups as Efficient Visible Light Photocatalysts.

    PubMed

    Eskandarloo, Hamed; Badiei, Alireza; Behnajady, Mohammad A; Mohammadi Ziarani, Ghodsi

    2015-01-01

    In this study, the photocatalytic efficiency of anatase-type TiO2 nanoparticles synthesized using the sol-gel low-temperature method, were enhanced by a combined process of copper reduction and surface hydroxyl groups enhancement. UV-light-assisted photo and NaBH4 -assisted chemical reduction methods were used for deposition of copper onto TiO2. The surface hydroxyl groups of TiO2 were enhanced with the assistance of NaOH modification. The prepared catalysts were immobilized on glass plates and used as the fixed-bed systems for the removal of phenazopyridine as a model drug contaminant under visible light irradiation. NaOH-modified Cu/TiO2 nanoparticles demonstrated higher photocatalytic efficiency than that of pure TiO2 due to the extending of the charge carriers lifetime and enhancement of the adsorption capacity of TiO2 toward phenazopyridine. The relationship of structure and performance of prepared nanoparticles has been established by using various techniques, such as XRD, XPS, TEM, EDX, XRF, TGA, DRS and PL. The effects of preparation variables, including copper content, reducing agents rate (NaBH4 concentration and UV light intensity) and NaOH concentration were investigated on the photocatalytic efficiency of NaOH-modified Cu/TiO2 nanoparticles. PMID:25809844

  6. Angular distribution of polarized light and its effect on light extraction efficiency in AlGaN deep-ultraviolet light-emitting diodes.

    PubMed

    Chen, Xinjuan; Ji, Cheng; Xiang, Yong; Kang, Xiangning; Shen, Bo; Yu, Tongjun

    2016-05-16

    Angular distribution of polarized light and its effect on light extraction efficiency (LEE) in AlGaN deep-ultraviolet (DUV) light-emitting diodes (LEDs) are investigated in this paper. A united picture is presented to describe polarized light's emission and propagation processes. It is found that the electron-hole recombinations in AlGaN multiple quantum wells produce three kinds of angularly distributed polarized emissions and propagation process can change their intensity distributions. By investigation the change of angular distributions in 277nm and 215nm LEDs, this work reveals that LEE can be significantly enhanced by modulating the angular distributions of polarized light of DUV LEDs. PMID:27409966

  7. Ultraviolet light photobiology of the protozoan Tetrahymena pyriformis and chemical reactivation of DNA damage

    SciTech Connect

    Wheeler, J.S.

    1988-01-01

    The tunable dye laser was developed in order to perform UV-B and UV-C (254-320 nm) action spectra studies on several different organisms. Using the laser, action spectra studies have been performed for Escherichia coli, Saccharomyces, Chlamydomonas, Caenorhabditis elegans, Paramecium, and Tetrahymena pyriformis. Studies generally indicate increasing LD{sub 50} values with increasing wavelength. Two notable findings were made: (1) The action spectra does not follow the DNA absorption spectra at 280, 290 and 295 nm; (2) The repair competent/repair defective sensitization factor does not remain constant throughout the wavelength region. In addition it was found that the repair defective strain of E. coli, Bs-1, showed an increase in survival with increasing UV irradiation, at certain dose levels. Further experiments were designed to better characterize the reactivation. Tetrahymena were exposed to UV-C and reactivated with methyl methanesulfonate (MMS) and 4-nitro quinoline oxide (4-NQO). In both cases survival was seen to increase after chemical exposure. Likewise, UV-C was found to reactivate chemical damage (MMS).

  8. Life in the light: nucleic acid photoproperties as a legacy of chemical evolution.

    PubMed

    Beckstead, Ashley A; Zhang, Yuyuan; de Vries, Mattanjah S; Kohler, Bern

    2016-09-21

    Photophysical investigations of the canonical nucleobases that make up DNA and RNA during the past 15 years have revealed that excited states formed by the absorption of UV radiation decay with subpicosecond lifetimes (i.e., <10(-12) s). Ultrashort lifetimes are a general property of absorbing sunscreen molecules, suggesting that the nucleobases are molecular survivors of a harsh UV environment. Encoding the genome using photostable building blocks is an elegant solution to the threat of photochemical damage. Ultrafast excited-state deactivation strongly supports the hypothesis that UV radiation played a major role in shaping molecular inventories on the early Earth before the emergence of life and the subsequent development of a protective ozone shield. Here, we review the general physical and chemical principles that underlie the photostability, or "UV hardiness", of modern nucleic acids and discuss the possible implications of these findings for prebiotic chemical evolution. In RNA and DNA strands, much longer-lived excited states are observed, which at first glance appear to increase the risk of photochemistry. It is proposed that the dramatically different photoproperties that emerge from assemblies of photostable building blocks may explain the transition from a world of molecular survival to a world in which energy-rich excited electronic states were eventually tamed for biological purposes such as energy transduction, signaling, and repair of the genetic machinery. PMID:27539809

  9. Spin Hall effect of light in photon tunneling

    SciTech Connect

    Luo Hailu; Wen Shuangchun; Shu Weixing; Fan Dianyuan

    2010-10-15

    We resolve the breakdown of angular momentum conservation on two-dimensional photon tunneling by considering the spin Hall effect (SHE) of light. This effect manifests itself as polarization-dependent transverse shifts of the field centroid when a classic wave packet tunnels through a prism-air-prism barrier. For the left or the right circularly polarized component, the transverse shift can be modulated by altering the refractive index gradient associated with the two prisms. We find that the SHE in conventional beam refraction can be evidently enhanced via photon tunneling mechanism. The transverse spatial shift is governed by the total angular momentum conservation law, while the transverse angular shift is governed by the total linear momentum conservation law. These findings open the possibility for developing new nanophotonic devices and can be extrapolated to other physical systems.

  10. Neuroprotective effects of PKC inhibition against chemical hypoxia.

    PubMed

    Pavlaković, G; Eyer, C L; Isom, G E

    1995-04-01

    The effect of potassium cyanide-induced chemical hypoxia on protein kinase C (PKC) translocation and cell injury was studied in differentiated PC12 cells. The cellular distribution of PKC in control cells and cells exposed to 100 microM and 1 mM KCN for 30 min. was visualized by use of an anti-PKC antibody and confocal laser scanning microscope. In control differentiated PC12 cells, PKC was localized perinuclearly, while following 12-phorbol 13-myristate acetate (PMA) or KCN it was translocated to the plasma and organelle membranes. Western blot analysis was used to quantify the translocation. Chemical hypoxia increased the membrane-bound PKC to 210% of control levels, while chelerythrine, a PKC inhibitor, and block of calcium influx into the cells (with calcium channel blocker and calcium-free medium) prevented this effect. Cyanide-induced PKC translocation persisted for at least 120 min. Cell injury was monitored by measuring lactate dehydrogenase (LDH) efflux from the cells 24 hr after addition of cyanide. PKC activation plays a role in hypoxic damage, since PKC down-regulation (by overnight exposure to PMA) or inhibition (with chelerythrine or staurosporine) conferred protection against KCN-induced cytotoxicity. Ca2+ channel blocker nifedipine also protected against chemical hypoxia. None of the pretreatments rendered complete protection against cyanide-induced hypoxia, indicating that PKC-independent mechanism(s) are also activated during chemical hypoxia and contribute to cell injury. PMID:7796171

  11. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration γ-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ≳ +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  12. Light-controlled modulation of gene expression by chemical optoepigenetic probes.

    PubMed

    Reis, Surya A; Ghosh, Balaram; Hendricks, J Adam; Szantai-Kis, D Miklos; Törk, Lisa; Ross, Kenneth N; Lamb, Justin; Read-Button, Willis; Zheng, Baixue; Wang, Hongtao; Salthouse, Christopher; Haggarty, Stephen J; Mazitschek, Ralph

    2016-05-01

    Epigenetic gene regulation is a dynamic process orchestrated by chromatin-modifying enzymes. Many of these master regulators exert their function through covalent modification of DNA and histone proteins. Aberrant epigenetic processes have been implicated in the pathophysiology of multiple human diseases. Small-molecule inhibitors have been essential to advancing our understanding of the underlying molecular mechanisms of epigenetic processes. However, the resolution offered by small molecules is often insufficient to manipulate epigenetic processes with high spatiotemporal control. Here we present a generalizable approach, referred to as 'chemo-optical modulation of epigenetically regulated transcription' (COMET), enabling high-resolution, optical control of epigenetic mechanisms based on photochromic inhibitors of human histone deacetylases using visible light. COMET probes may be translated into new therapeutic strategies for diseases where conditional and selective epigenome modulation is required. PMID:26974814

  13. A novel photobioreactor structure using optical fibers as inner light source to fulfill flashing light effects of microalgae.

    PubMed

    Xue, Shengzhang; Zhang, Qinghua; Wu, Xia; Yan, Chenghu; Cong, Wei

    2013-06-01

    In this work, a novel photobioreactor structure using optical fibers being fixed vertically to culture flow direction as inner light source was proposed to fulfill flashing light effects (FLE) of microalgae, so as to obtain high light efficiency. Three types of optical-fiber photobioreactor fulfilling FLE of microalgae, i.e. air-driven panel, pump-driven panel and stirred tank type, were proposed and a 130 L airlift panel one was practically constructed on which both cold (light profile, liquid velocity) and hot model tests were carried out. Results demonstrated that it could produce uniformed light/dark frequencies being over 10 Hz and microalgae productivity increased by 43% and 38% for Spirulina platensis and Scenedesmus dimorphus respectively, compared with the control. This suggested the structure to be a viable and promising option for future photobioreactors. PMID:23612173

  14. Reproductive effects in birds exposed to pesticides and industrial chemicals.

    PubMed

    Fry, D M

    1995-10-01

    Environmental contamination by agricultural chemicals and industrial waste disposal results in adverse effects on reproduction of exposed birds. The diversity of pollutants results in physiological effects at several levels, including direct effects on breeding adults as well as developmental effects on embryos. The effects on embryos include mortality or reduced hatchability, failure of chicks to thrive (wasting syndrome), and teratological effects producing skeletal abnormalities and impaired differentiation of the reproductive and nervous systems through mechanisms of hormonal mimicking of estrogens. The range of chemical effects on adult birds covers acute mortality, sublethal stress, reduced fertility, suppression of egg formation, eggshell thinning, and impaired incubation and chick rearing behaviors. The types of pollutants shown to cause reproductive effects include organochlorine pesticides and industrial pollutants, organophosphate pesticides, petroleum hydrocarbons, heavy metals, and in a fewer number of reports, herbicides, and fungicides. o,p'-DDT, polychlorinated biphenyls (PCBs), and mixtures of organochlorines have been identified as environmental estrogens affecting populations of gulls breeding in polluted "hot spots" in southern California, the Great Lakes, and Puget Sound. Estrogenic organochlorines represent an important class of toxicants to birds because differentiation of the avian reproductive system is estrogen dependent. PMID:8593865

  15. Reproductive effects in birds exposed to pesticides and industrial chemicals

    SciTech Connect

    Fry, D.M.

    1995-10-01

    Environmental contamination by agricultural chemicals and industrial waste disposal results in adverse effects on reproduction of exposed birds. The diversity of pollutants results in physiological effects at several levels, including direct effects on breeding adults as well as developmental effects on embryos. The effects on embryos include mortality or reduced hatchability, failure of chicks to thrive (wasting syndrome), and teratological effects producing skeletal abnormalities and impaired differentiation of the reproductive and nervous systems through mechanisms of hormonal mimicking of estrogens. The range of chemical effects on adult birds covers acute mortality, sublethal stress, reduced fertility, suppression of egg formation, eggshell thinning, and impaired incubation and chick rearing behaviors. The types of pollutants shown to cause reproductive effects include organochlorine pesticides and industrial pollutants, organophosphate pesticides, petroleum hydrocarbons, heavy metals, and in a fewer number of reports, herbicides, and fungicides. o,p`-DDT, polychlorinated biphenyls (PCBs), and mixtures of organochlorines have been identified as environmental estrogens affecting populations of gulls breeding in polluted {open_quotes}hot spots{close_quotes} in southern California, the Great Lakes, and Puget Sound. Estrogenic organochlorines represent an important class of toxicants to birds because differentiation of the avian reproductive system is estrogen dependent. 85 refs.

  16. Reproductive effects in birds exposed to pesticides and industrial chemicals.

    PubMed Central

    Fry, D M

    1995-01-01

    Environmental contamination by agricultural chemicals and industrial waste disposal results in adverse effects on reproduction of exposed birds. The diversity of pollutants results in physiological effects at several levels, including direct effects on breeding adults as well as developmental effects on embryos. The effects on embryos include mortality or reduced hatchability, failure of chicks to thrive (wasting syndrome), and teratological effects producing skeletal abnormalities and impaired differentiation of the reproductive and nervous systems through mechanisms of hormonal mimicking of estrogens. The range of chemical effects on adult birds covers acute mortality, sublethal stress, reduced fertility, suppression of egg formation, eggshell thinning, and impaired incubation and chick rearing behaviors. The types of pollutants shown to cause reproductive effects include organochlorine pesticides and industrial pollutants, organophosphate pesticides, petroleum hydrocarbons, heavy metals, and in a fewer number of reports, herbicides, and fungicides. o,p'-DDT, polychlorinated biphenyls (PCBs), and mixtures of organochlorines have been identified as environmental estrogens affecting populations of gulls breeding in polluted "hot spots" in southern California, the Great Lakes, and Puget Sound. Estrogenic organochlorines represent an important class of toxicants to birds because differentiation of the avian reproductive system is estrogen dependent. PMID:8593865

  17. The effect of environmental chemicals on the tumor microenvironment

    PubMed Central

    Casey, Stephanie C.; Vaccari, Monica; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Barcellos-Hoff, Mary Helen; Brown, Dustin G.; Chapellier, Marion; Christopher, Joseph; Curran, Colleen S.; Forte, Stefano; Hamid, Roslida A.; Heneberg, Petr; Koch, Daniel C.; Krishnakumar, P.K.; Laconi, Ezio; Maguer-Satta, Veronique; Marongiu, Fabio; Memeo, Lorenzo; Mondello, Chiara; Raju, Jayadev; Roman, Jesse; Roy, Rabindra; Ryan, Elizabeth P.; Ryeom, Sandra; Salem, Hosni K.; Scovassi, A.Ivana; Singh, Neetu; Soucek, Laura; Vermeulen, Louis; Whitfield, Jonathan R.; Woodrick, Jordan; Colacci, Anna Maria; Bisson, William H.; Felsher, Dean W.

    2015-01-01

    Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis. PMID:26106136

  18. The effect of environmental chemicals on the tumor microenvironment.

    PubMed

    Casey, Stephanie C; Vaccari, Monica; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Barcellos-Hoff, Mary Helen; Brown, Dustin G; Chapellier, Marion; Christopher, Joseph; Curran, Colleen S; Forte, Stefano; Hamid, Roslida A; Heneberg, Petr; Koch, Daniel C; Krishnakumar, P K; Laconi, Ezio; Maguer-Satta, Veronique; Marongiu, Fabio; Memeo, Lorenzo; Mondello, Chiara; Raju, Jayadev; Roman, Jesse; Roy, Rabindra; Ryan, Elizabeth P; Ryeom, Sandra; Salem, Hosni K; Scovassi, A Ivana; Singh, Neetu; Soucek, Laura; Vermeulen, Louis; Whitfield, Jonathan R; Woodrick, Jordan; Colacci, Annamaria; Bisson, William H; Felsher, Dean W

    2015-06-01

    Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis. PMID:26106136

  19. Restorative Lighting Environments—Does the Focus of Light Have an Effect on Restorative Experiences?

    NASA Astrophysics Data System (ADS)

    Nikunen, Heli Johanna; Korpela, Kalevi Mikael

    This study investigated how focusing light on different elements of a scene affects the stress-alleviating, restorative experience. Three night time scenes were created with the Lightscape computer program. Each scene was illuminated in two different ways, one focusing light on roads and parking lots and the other on vegetation, resulting altogether in six views. It was expected that focusing light on vegetation would result in higher ratings of restorative experience. The simulated views were rated by 35 participants using the Perceived Restorativeness Scale (PRS) and the Restoration Outcome Scale (ROS). In accordance with our hypothesis, focusing light towards greenery vs. parking lots and roads resulted in higher PRS and ROS ratings. The results suggest that lighting offers considerable potential for enhancing the restorativeness of urban night time environments.

  20. Effect of Monochromic Light-emitting Diode Light with Different Color on the Growth and Reproductive Performances of Breeder Geese.

    PubMed

    Chang, S C; Lin, M J; Zhuang, Z X; Huang, S Y; Lin, T Y; Jea, Y S; Fan, Y K; Lee, T T

    2016-06-01

    The purpose of this study was to investigate the effect of monochromic light-emitting diode (LED) light with different color on the growth and reproductive performances of white Roman breeder geese. A randomized complete batch design was utilized for the trial, and the replicate was regarded as one batch. Twenty ganders and fifty-five dames were used in batch 1 (started on 2011/6/17 and ended on 2012/1/31), thirty ganders and eighty-four dames were used in batch 2 (started on 2012/3/23 and ended on 2012/10/26), and thirty ganders and seventy-two dames were used in batch 3 (started on 2013/3/12 and ended on 2013/12/20). Two hundred and ninety-one geese were randomly assigned to 6 rooms in an environmentally controlled house. They were randomly allotted into one of three monochromatic light treatments: Blue, red, or white. The results showed that there was no significant difference in body weight among the three lighting groups at any point throughout the experimental period. However, compared to the blue light group, significantly more eggs were produced by the red and white light groups (p<0.05). Furthermore, the laying period of the red light group was significantly longer than that of other two groups (p<0.05). In conclusion, our results suggested that red LED-light has the best effect on reproductive performance (i.e. longer laying period and higher total eggs number) at 30 lux light intensity, and is therefore a better choice for the management of breeding geese than blue or white LED-light. PMID:26954165

  1. Effect of Monochromic Light-emitting Diode Light with Different Color on the Growth and Reproductive Performances of Breeder Geese

    PubMed Central

    Chang, S. C.; Lin, M. J.; Zhuang, Z. X.; Huang, S. Y.; Lin, T. Y.; Jea, Y. S.; Fan, Y. K.; Lee, T. T.

    2016-01-01

    The purpose of this study was to investigate the effect of monochromic light-emitting diode (LED) light with different color on the growth and reproductive performances of white Roman breeder geese. A randomized complete batch design was utilized for the trial, and the replicate was regarded as one batch. Twenty ganders and fifty-five dames were used in batch 1 (started on 2011/6/17 and ended on 2012/1/31), thirty ganders and eighty-four dames were used in batch 2 (started on 2012/3/23 and ended on 2012/10/26), and thirty ganders and seventy-two dames were used in batch 3 (started on 2013/3/12 and ended on 2013/12/20). Two hundred and ninety-one geese were randomly assigned to 6 rooms in an environmentally controlled house. They were randomly allotted into one of three monochromatic light treatments: Blue, red, or white. The results showed that there was no significant difference in body weight among the three lighting groups at any point throughout the experimental period. However, compared to the blue light group, significantly more eggs were produced by the red and white light groups (p<0.05). Furthermore, the laying period of the red light group was significantly longer than that of other two groups (p<0.05). In conclusion, our results suggested that red LED-light has the best effect on reproductive performance (i.e. longer laying period and higher total eggs number) at 30 lux light intensity, and is therefore a better choice for the management of breeding geese than blue or white LED-light. PMID:26954165

  2. The effects of specified chemical meals on food intake.

    PubMed

    Koopmans, H S; Maggio, C A

    1978-10-01

    Rats received intragastric infusions of various specified chemical meals and were subsequently tested for a reduction in food intake. A second experiment, using a novel technique, tested for conditioned aversion to the meal infusions. The nonnutritive substances, kaolin clay and emulsified fluorocarbon, had no significant effect on food intake. Infusions of 1 M glucose and 1 M sorbitol reduced feeding behavior, but the 1 M sorbitol infusion also produced a conditioned aversion to flavored pellets paired with the sorbitol infusion, showing that the reduced feeding could have been caused by discomfort. Infusion of a high-fat meal consisting of emulsified triolein mixed with small amounts of sugar and protein or the rat's normal liquid diet, Nutrament, also reduced food intake, and both infusions failed to produce a conditioned aversion. The use of specified meals to understand the chemical basis of satiety requires a sensitive behavioral test to establish that the meal does not cause discomfort or other nonspecific effects. PMID:707387

  3. The Effect of Surface Chemical Functionality Upon Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Joseph G., Jr.; Wohl, Christopher J.; Doss, Jereme; Spence, Destiny; Kreeger, Richard E.; Palacios, Jose; Knuth, Taylor; Hadley, Kevin R.; McDougal, Nicholas D.

    2015-01-01

    In nature, anti-freeze proteins present in fish utilize specific organic functionalities to disrupt ice crystal formation and propagation. Based on these structures, surfaces with controlled chemical functionality and chain length were evaluated both experimentally and computationally to assess the effect of both parameters in mitigating ice formation. Linear aliphatic dimethylethoxysilanes terminated with methyl or hydroxyl groups were prepared, characterized, and used to coat aluminum. The effect upon icing using a microdroplet freezing apparatus and the Adverse Environment Rotor Test Stand found hydroxyl-terminated materials exhibited a greater propensity for ice formation and adhesion. Molecular dynamics simulations of a silica substrate bearing functionalized species of similar composition were brought into contact with a pre-equilibrated ice crystal. Several parameters including chain mobility were monitored to ascertain the size of a quasi-liquid layer. The studies suggested that chain mobility affected the interface between ice and the surface more than terminal group chemical composition.

  4. Vertical Microcavity Organic Light-emitting Field-effect Transistors

    PubMed Central

    Hu, Yongsheng; Lin, Jie; Song, Li; Lu, Qipeng; Zhu, Wanbin; Liu, Xingyuan

    2016-01-01

    Organic light-emitting field-effect transistors (OLEFETs) are regarded as a novel kind of device architecture for fulfilling electrical-pumped organic lasers. However, the realization of OLEFETs with high external quantum efficiency (EQE) and high brightness simultaneously is still a tough task. Moreover, the design of the resonator structure in LED is far from satisfactory. Here, OLEFETs with EQE of 1.5% at the brightness of 2600 cdm−2, and the corresponding ON/OFF ratio and current efficiency reaches above 104 and 3.1 cdA−1, respectively, were achieved by introducing 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN) as a charge generation layer. Moreover, a vertical microcavity based on distributed Bragg reflector (DBR) and Ag source/drain electrodes is successfully introduced into the high performance OLEFETs, which results in electroluminescent spectrum linewidth narrowing from 96 nm to 6.9 nm. The results manifest the superiority of the vertical microcavity as an optical resonator in OLEFETs, which sheds some light on achieving the electrically pumped organic lasers. PMID:26986944

  5. Vertical Microcavity Organic Light-emitting Field-effect Transistors.

    PubMed

    Hu, Yongsheng; Lin, Jie; Song, Li; Lu, Qipeng; Zhu, Wanbin; Liu, Xingyuan

    2016-01-01

    Organic light-emitting field-effect transistors (OLEFETs) are regarded as a novel kind of device architecture for fulfilling electrical-pumped organic lasers. However, the realization of OLEFETs with high external quantum efficiency (EQE) and high brightness simultaneously is still a tough task. Moreover, the design of the resonator structure in LED is far from satisfactory. Here, OLEFETs with EQE of 1.5% at the brightness of 2600 cdm(-2), and the corresponding ON/OFF ratio and current efficiency reaches above 10(4) and 3.1 cdA(-1), respectively, were achieved by introducing 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN) as a charge generation layer. Moreover, a vertical microcavity based on distributed Bragg reflector (DBR) and Ag source/drain electrodes is successfully introduced into the high performance OLEFETs, which results in electroluminescent spectrum linewidth narrowing from 96 nm to 6.9 nm. The results manifest the superiority of the vertical microcavity as an optical resonator in OLEFETs, which sheds some light on achieving the electrically pumped organic lasers. PMID:26986944

  6. Vertical Microcavity Organic Light-emitting Field-effect Transistors

    NASA Astrophysics Data System (ADS)

    Hu, Yongsheng; Lin, Jie; Song, Li; Lu, Qipeng; Zhu, Wanbin; Liu, Xingyuan

    2016-03-01

    Organic light-emitting field-effect transistors (OLEFETs) are regarded as a novel kind of device architecture for fulfilling electrical-pumped organic lasers. However, the realization of OLEFETs with high external quantum efficiency (EQE) and high brightness simultaneously is still a tough task. Moreover, the design of the resonator structure in LED is far from satisfactory. Here, OLEFETs with EQE of 1.5% at the brightness of 2600 cdm‑2, and the corresponding ON/OFF ratio and current efficiency reaches above 104 and 3.1 cdA‑1, respectively, were achieved by introducing 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN) as a charge generation layer. Moreover, a vertical microcavity based on distributed Bragg reflector (DBR) and Ag source/drain electrodes is successfully introduced into the high performance OLEFETs, which results in electroluminescent spectrum linewidth narrowing from 96 nm to 6.9 nm. The results manifest the superiority of the vertical microcavity as an optical resonator in OLEFETs, which sheds some light on achieving the electrically pumped organic lasers.

  7. Morphogenesis in Schizophyllum commune. II. Effects of Monochromatic Light 1

    PubMed Central

    Perkins, John H.; Gordon, Solon A.

    1969-01-01

    The photoinduction of fruiting bodies by light of defined wavelengths was studied in the fungus Schizophyllum commune Fr. Several properties of the induction were established. (1) The exposure-response relationship for induced fruiting was determined for light of 448 nm. (2) The Bunsen-Roscoe Law of Reciprocity was found to hold for the photoinduction of fruiting bodies for the interval 36 to 2000 sec with light of 448 nm. (3) Light of wavelengths from 320 nm to 525 nm induced fruiting bodies. Although the photoreceptor is unknown, it may be a flavin rather than a carotenoid, because light in the near ultraviolet (350 nm-400 nm) was inductive. (4) Neither red light (660 nm) nor far-red light (730 nm) induced fruiting bodies or affected the sensitivity of the fungus toward photoinduction by blue light (448 nm). PMID:5380928

  8. Toxic effects of occupational and environmental chemicals on the testes

    SciTech Connect

    Sever, L.E.; Hessol, N.A.

    1983-01-01

    This paper examines evidence for effects of occupational chemicals on male reproduction. We consider primarily human data, and much of that from epidemiologic studies. We use animal studies to illustrate points, but the theme is the human experience. The approach is based on examining reproductive function as an indicator of toxic effects. Testicular structure and function is briefly discussed. We provide a brief review of relevant structure, function and hormonal control. We describe the anatomy of the testis and its histological structure. We then discuss the testis from the point of view of exocrine and endocrine function and the relationship of the testis to other endocrinological organs. This is followed by a review of methods for assessing human testicular function, including reproductive histories, sperm analysis, assessment of hormonal status, and histological studies. Although the primary focus is on human studies, we consider briefly general categories of chemicals shown to have a testicular effect in animal studies and also animal evidence of mechanisms of action associated with testicular toxicology. Specific chemicals shown to affect reproduction in the human male are reviewed and directions for future research in this area discussed.

  9. Mechanical and chemical effects of ion-texturing biomedical polymers

    NASA Technical Reports Server (NTRS)

    Weigand, A. J.; Cenkus, M. A.

    1979-01-01

    To determine whether sputter etching may provide substantial polymer surface texturing with insignificant changes in chemical and mechanical properties, an 8 cm beam diameter, electron bombardment, argon ion source was used to sputter etch (ion-texture process) nine biomedical polymers. The materials included silicone rubber, 32% carbon impregnated polyolefin, polyoxymethylene, polytetrafluoroethylene, ultrahigh molecular weight (UHMW) polyethylene, UHMW polyethylene with carbon fibers (10%), and several polyurethanes (bioelectric, segmented, and cross linked). Ion textured microtensile specimens of each material except UHMW polyethylene and UHMW polyethylene with 10% carbon fibers were used to determine the effect of ion texturing on tensile properties. Scanning electron microscopy was used to determine surface morphology changes, and electron spectroscopy for chemical analysis was used to analyze the near surface chemical changes that result from ion texturing. Ion energies of 500 eV with beam current densities ranging from 0.08 to 0.19 mA/sq cm were used to ion texture the various materials. Standard microtensile specimens of seven polymers were exposed to a saline environment for 24 hours prior to and during the tensile testing. The surface chemical changes resulting from sputter etching are minimal in spite of the often significant changes in the surface morphology.

  10. Effects of absorption and desorption on the chemical stress field

    NASA Astrophysics Data System (ADS)

    Zhang, Tong-Yi; Ko, Sun-Chien; Lee, Sanboh

    2002-02-01

    The present work studies the effects of absorption and desorption on the chemical stress field in a membrane during permeation or both-side charging of a diffusing species. The permeation and both-side charging processes are analyzed with the consideration of the absorption and desorption processes, wherein the flux continuity boundary conditions are adopted. The results show that the chemical stresses are compressive near the surfaces and tensile in the center of the membrane. The maximum magnitude of stress occurs at the entry surface for the permeation process and at both surfaces for the both-side charging process. For the permeation process, the compressive stress at the entry surface increases with time to a maximum and then decreases with time gradually to zero. A similar phenomenon is found at both surfaces in the both-side charging process. In both processes, the stress magnitude depends upon the ratio of the drift velocity through surface to the drift velocity through bulk. When this ratio approaches infinity, the flux continuity boundary conditions reduce to the concentration boundary condition and the highest chemical stress field will be produced. Therefore, reducing the drift velocity through surface would be an efficient means to reduce the strength of the chemical stress. In general, designed surface alloying can introduce diffusing species traps at the surfaces of a membrane, which may efficiently decrease the drift velocity through surface.

  11. Performance of the VUV high resolution and high flux beamline for chemical dynamics studies at the Advanced Light Source

    SciTech Connect

    Heimann, P.A.; Koike, M. Hsu, C.W.

    1996-07-01

    At the Advanced Light Source an undulator beamline, with an energy range from 6 to 30 eV, has been constructed for chemical dynamics experiments. The higher harmonics of the undulator are suppressed by a novel, windowless gas filter. In one branchline high flux, 2 % bandwidth radiation is directed toward an end station for photodissociation and crossed molecular beam experiments. A photon flux of photon/sec has been measured at this end station. In a second branchline a 6.65 m off- plane Eagle monochromator delivers narrow bandwidth radiation to an end station for photoionization studies. At this second end station a peak flux of 3 x 10{sup 11} was observed for 25,000 resolving power. This monochromator has achieved a resolving power of 70,000 using a 4800 grooves/mm grating, one of the highest resolving powers obtained by a VUV monochromator.

  12. Using light to shape chemical gradients for parallel and automated analysis of chemotaxis

    PubMed Central

    Collins, Sean R; Yang, Hee Won; Bonger, Kimberly M; Guignet, Emmanuel G; Wandless, Thomas J; Meyer, Tobias

    2015-01-01

    Numerous molecular components have been identified that regulate the directed migration of eukaryotic cells toward sources of chemoattractant. However, how the components of this system are wired together to coordinate multiple aspects of the response, such as directionality, speed, and sensitivity to stimulus, remains poorly understood. Here we developed a method to shape chemoattractant gradients optically and analyze cellular chemotaxis responses of hundreds of living cells per well in 96-well format by measuring speed changes and directional accuracy. We then systematically characterized migration and chemotaxis phenotypes for 285 siRNA perturbations. A key finding was that the G-protein Giα subunit selectively controls the direction of migration while the receptor and Gβ subunit proportionally control both speed and direction. Furthermore, we demonstrate that neutrophils chemotax persistently in response to gradients of fMLF but only transiently in response to gradients of ATP. The method we introduce is applicable for diverse chemical cues and systematic perturbations, can be used to measure multiple cell migration and signaling parameters, and is compatible with low- and high-resolution fluorescence microscopy. PMID:25908733

  13. Ginger: Measuring Gravitomagnetic Effects by Means of Light

    NASA Astrophysics Data System (ADS)

    Tartaglia, Angelo

    2015-01-01

    GINGER is a proposal for a new experiment aimed to the detection of the gravito-magnetic Lense-Thirring effect at the surface of the Earth. A three-dimensional set of ring lasers will be mounted on a rigid "monument". In a ring laser a light beam traveling counterclockwise is superposed to another beam traveling in the opposite sense. The anisotropy in the propagation leads to standing waves with slightly different frequencies in the two directions; the resulting beat frequency is proportional to the absolute rotation rate in space, including the gravito-magnetic drag. The experiment is planned to be built in the Gran Sasso National Laboratories in Italy and is based on an international collaboration among four Italian groups, the Technische Universität München and the University of Canterbury in Christchurch (NZ).

  14. Reduced product yield in chemical processes by second law effects

    NASA Technical Reports Server (NTRS)

    England, C.; Funk, J. E.

    1980-01-01

    An analysis of second law effects in chemical processes, where product yield is explicitly related to the individual irreversibilities within the process to indicate a maximum theoretical yield, is presented. Examples are given that indicate differences between first and second law approaches toward process efficiency and process yield. This analysis also expresses production capacity in terms of the heating value of a product. As a result, it is particularly convenient in analyzing fuel conversion plants and their potential for improvement. Relationships are also given for the effects of irreversibilities on requirements for process heat and for feedstocks.

  15. Road crossing behavior under traffic light conflict: Modulating effects of green light duration and signal congruency.

    PubMed

    Lange, Florian; Haiduk, Michael; Boos, Moritz; Tinschert, Peter; Schwarze, Anke; Eggert, Frank

    2016-10-01

    A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced by slightly adjusting its color. Our findings highlight that the observation of real-world behavior at intersections and the experimental analysis of psychological processes under controlled laboratory conditions can complement each other in identifying risk factors of risky road crossing behavior. Based on this combination, our study elaborates on promising measures to improve safety at signalized intersections. PMID:27474874

  16. The darkening of zinc yellow: XANES speciation of chromium in artist;s paints after light and chemical exposures

    SciTech Connect

    Zanella, Luciana; Casadio, Francesca; Gray, Kimberly A.; Warta, Richard; Ma, Qing; Gaillard, Jean-François

    2012-03-14

    The color darkening of selected brushstrokes of the masterpiece A Sunday on La Grande Jatte - 1884 (by Georges Seurat) has been attributed to the alteration of the chromate pigment zinc yellow. The pigment originally displays a bright greenish-yellow color but may undergo, after aging, darkening to a dull, ocher tone. We used XANES to probe the oxidation state of Cr on paint reconstructions, and show that color changes are associated with the reduction of Cr(VI) to Cr(III). Paint mixtures containing the pigment and linseed oil to mimic mixtures used in La Grande Jatte were subjected to artificial aging in the presence of light, SO{sub 2}, and variable air humidity - 50 and 90% relative humidity. High relative humidity led to the largest degree of Cr(VI) reduction whereas low relative humidity promoted light-induced alterations. These results are corroborated by visible reflectance measurements on the same laboratory samples and contribute to a better understanding of the chemical reactivity of chromate pigments, which are present in many historical works of art.

  17. Effects of chemical disturbances on intertidal benthic assemblages.

    PubMed

    Mayer-Pinto, Mariana; Ignacio, Barbara Lage

    2015-02-15

    Contamination is a particular harmful type of chemical disturbance and predicting their effects on natural systems is very complex. Effects of disturbances vary in space and time and depend, among other things, on the type and age of organisms, the habitat being studied and the complex interactions occurring in the systems. Most impact analyses of contaminants are however still done with limited number of selected organisms under laboratory conditions. Manipulative experiments done in situ are important to measure ecologically relevant responses of contaminant effects on marine systems. Ecological approaches on contamination studies, accounting for interactions among species and the environment are essential to understand how such disturbances affect systems. We evaluated the effects of bleach and permethrin, two common and pervasive contaminants, on intertidal benthic assemblages in two different successional stages, mature and young. There were no impacts on the overall structure of assemblages, regardless of their age. The lack of effects on the structure of assemblages might be due to the intrinsic characteristic of the habitat studied, which provide few sinks for contaminants, as well as the inherent features of the organisms themselves. Bleach did cause, however, a decrease in the abundance of limpets, which can have further consequences to these systems. This study shows the importance of studies on chemical disturbances done under relevant natural scenarios and that efficient management policies of natural systems will only achieve successful responses with properly designed experiments under natural conditions. PMID:25460934

  18. Light and Plants. A Series of Experiments Demonstrating Light Effects on Seed Germination, Plant Growth, and Plant Development.

    ERIC Educational Resources Information Center

    Downs, R. J.; And Others

    A brief summary of the effects of light on plant germination, growth and development, including photoperiodism and pigment formation, introduces 18 experiments and demonstrations which illustrate aspects of these effects. Detailed procedures for each exercise are given, the expected results outlined, and possible sources of difficulty discussed.…

  19. Long-term effects of chemical disasters. Lessons and results from Seveso.

    PubMed

    Bertazzi, P A

    1991-07-01

    Fourteen years after its occurrence (10 July 1976) the Seveso accident is still considered the prototype for chemical disasters. Thousands of persons were potentially exposed to dioxin after an uncontrolled development during the manufacture of trichlorophenol in a chemical plant. The most evident adverse health effect ascertained was chloracne (193 cases). Other reversible early effects noted were peripheral neuropathy and liver enzyme induction. The ascertainment of other, possibly severe sequelae of dioxin exposure (e.g., birth defects) was hampered by inadequate information; however, generally, no increased risks were evident. Mortality studies shed some light on the long-term effects. An unusual cardiovascular mortality pattern was reported in the exposed population. Cancer mortality findings after 10 years do not allow firm conclusions to be drawn, but are suggestive of a departure from expectations for certain types of cancer; the ongoing cancer incidence study will further explore these hypotheses. A variety of lessons were learned after this accident, and some have been incorporated into international regulations regarding industrial activities and environmental safety. This paper focuses on lessons relevant to the design and conduct of health studies in the aftermath of chemical disasters, with special emphasis given to identification of the study population, ascertainment of individual exposure, and attainment of information. PMID:1835132

  20. Spin Hall effect of light in inhomogeneous nonlinear medium

    NASA Astrophysics Data System (ADS)

    Li, Hehe; Li, Xinzhong

    2016-01-01

    In this paper, we investigate the spin Hall effect of a polarized Gaussian beam (GB) in a smoothly inhomogeneous isotropic and nonlinear medium using the method of the eikonal-based complex geometrical optics which describes the phase front and cross-section of a light beam using the quadratic expansion of a complex-valued eikonal. The linear complex-valued eikonal terms are introduced to describe the polarization-dependent transverse shifts of the beam in inhomogeneous nonlinear medium which is called the spin Hall effect of beam. We know that the spin Hall effect of beam is affected by the nonlinearity of medium and include two parts, one originates from the coupling between the spin angular momentum and the extrinsic orbital angular momentum due to the curve trajectory of the center of gravity of the polarized GB and the other from the coupling between the spin angular momentum and the intrinsic orbital angular momentum due to the rotation of the beam with respect to the central ray.

  1. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals

    USGS Publications Warehouse

    Calfee, R.D.; Little, E.E.

    2003-01-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol?? GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity.

  2. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals.

    PubMed

    Calfee, Robin D; Little, Edward E

    2003-07-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity. PMID:12836977

  3. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1990-11-01

    The objective of this research is to elucidate the role of additives on the ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies of NO adsorption, reaction probing, study state rate measurement, and transient kinetic study. A better understanding of the role of additive on the synthesis reaction may allow them to use chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas. 49 refs., 6 figs., 3 tabs.

  4. Modeling complex chemical effects in turbulent nonpremixed combustion

    NASA Technical Reports Server (NTRS)

    Smith, Nigel S. A.

    1995-01-01

    Virtually all of the energy derived from the consumption of combustibles occurs in systems which utilize turbulent fluid motion. Since combustion is largely related to the mixing of fluids and mixing processes are orders of magnitude more rapid when enhanced by turbulent motion, efficiency criteria dictate that chemically powered devices necessarily involve fluid turbulence. Where combustion occurs concurrently with mixing at an interface between two reactive fluid bodies, this mode of combustion is called nonpremixed combustion. This is distinct from premixed combustion where flame-fronts propagate into a homogeneous mixture of reactants. These two modes are limiting cases in the range of temporal lag between mixing of reactants and the onset of reaction. Nonpremixed combustion occurs where this lag tends to zero, while premixed combustion occurs where this lag tends to infinity. Many combustion processes are hybrids of these two extremes with finite non-zero lag times. Turbulent nonpremixed combustion is important from a practical standpoint because it occurs in gas fired boilers, furnaces, waste incinerators, diesel engines, gas turbine combustors, and afterburners etc. To a large extent, past development of these practical systems involved an empirical methodology. Presently, efficiency standards and emission regulations are being further tightened (Correa 1993), and empiricism has had to give way to more fundamental research in order to understand and effectively model practical combustion processes (Pope 1991). A key element in effective modeling of turbulent combustion is making use of a sufficiently detailed chemical kinetic mechanism. The prediction of pollutant emission such as oxides of nitrogen (NO(x)) and sulphur (SO(x)) unburned hydrocarbons, and particulates demands the use of detailed chemical mechanisms. It is essential that practical models for turbulent nonpremixed combustion are capable of handling large numbers of 'stiff' chemical species

  5. The effect of monochromatic light on broiler growth and development.

    PubMed

    Rozenboim, I; Biran, I; Uni, Z; Robinzon, B; Halevy, O

    1999-01-01

    Artificial illumination, including light quality, is crucial in modem broiler management. In the present study, a new, highly efficient, monochromatic light system has been developed for broilers. One hundred and eighty male broiler chicks (Anak) were divided into four light treatment groups (n = 45) in three replicates each. All birds were housed in a single room previously divided by wooden bars into 12 sealed cells of 1 m2. Feed and water were provided for ad libitum consumption. Light intensity was 0.1 W/m2 at the height of birds' heads and was scheduled for 23 h of light and 1 h of dark during the entire experimental period. Light treatments were: control white (mini-incandescent light bulbs), blue (480 nm), green (560 nm), and red (660 nm). Body weight was recorded periodically, feed consumption was measured daily, and feed efficiency was calculated. Blood samples were taken at 1, 9, and 32 d of age and plasma testosterone was determined. Two necropsies were conducted, at 23 and 35 d of age, and selected glands and organs were weighed. In the group reared under green light, a significant enhancement in weight gain was observed as early as 3 d of age; this gain was maintained during the entire experimental period. Broilers reared under blue light had a later onset of growth enhancement and were significantly heavier than those reared under white and red light at 20 d of age. Plasma testosterone levels were significantly higher in birds reared under blue light. Breast muscle weights were significantly higher in the birds reared under green light at 23 and 35 d of age. These results suggest that green and blue light stimulate growth. PMID:10023760

  6. The effect of age and pre-light melatonin concentration on the melatonin sensitivity to dim light.

    PubMed

    Nathan, P J; Burrows, G D; Norman, T R

    1999-05-01

    The hormone melatonin is secreted at night from the pineal gland, with light being a potent inhibitor of its secretion. Age related decreases in plasma melatonin concentrations have indicated that this may be related to pineal calcification with aging. Recently, it was shown that the melatonin sensitivity to light may be a biological marker of bipolar disorder. However, on average, patients were older than the control group in most studies, and it is not known if age has an effect on the melatonin suppression by light. To test this hypothesis, the present study investigated the effect of age on the melatonin sensitivity to dim light (200 lux). Participants were grouped into three age groups. On the testing night, they were placed in a dark room from 21.00 h to 02.30 h. Light exposure was for an hour from midnight to 01.00 h. Blood samples were collected at regular intervals for measurement of plasma melatonin. No significant differences were found in the percentage suppression of melatonin within the age groups defined in the present study (P > 0.5). No correlation was also found between age and percentage suppression of melatonin (r2 = 0.007; P > 0.1). Our results suggest that the melatonin suppression by light (200 lux) is not affected by age. PMID:10435774

  7. Impurities in sodium thiocyanate liquors and their effect on light adsorption

    SciTech Connect

    Voitkovskii, B.F.

    1982-01-01

    The adsorption of ultraviolet light by aqueous solutions of sodium thiocyanate was investigated. The effects of impurities on the light adsorption were of particular interest. Data on the light adsorption in the 254-365 nm wavelength range of various sodium salts, as well as iron, nickel, copper, lead, and chromium thiocyanates, were presented in tabular form. It was concluded that the light adsorption was effected by impurities that were products of decomposition, polymerization and other conversions of sodium thiocyanate.

  8. Effects of blue light on the circadian system and eye physiology

    PubMed Central

    Ferguson, Ian; Tsubota, Kazuo

    2016-01-01

    Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400–490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health. PMID:26900325

  9. Performance effects of chemical warfare antidotes: A perspective

    SciTech Connect

    Caldwell, J.A.

    1992-07-01

    The threat that enemy forces may use chemical warfare against United States military troops has caused the medical research and development community to find effective antidotes. Particularly in the case of nerve agent poisoning, the timely use of antidote therapies represents the key to survival in contaminated environments. Current training doctrine instructs soldiers how to recognize the symptoms of nerve agent exposure, and then how to counteract the life-threatening effects with the administration of atropine sulfate and pralidoxime chloride. However, these compounds can produce performance degrading effects on their own even when no chemical agent is present. Particularly in the case of the aviator, who is expected to exercise very precise control over an inherently complex vehicle such as a helicopter, the impact of self-administered antidotes should be fully appreciated. The present review briefly summarizes what is known about the actions and performance effects of both atropine and pralidoxime chloride, and recommendations are made concerning the need for additional research.

  10. Effects of chemical additives on microbial enhanced oil recovery processes

    SciTech Connect

    Bryant, R.S.; Chase, K.L.; Bertus, K.M.; Stepp, A.K.

    1989-12-01

    An extensive laboratory study has been conducted to determine (1) the role of the microbial cells and products in oil displacement, (2) the relative rates of transport of microbial cells and chemical products from the metabolism of nutrient in porous media, and (3) the effects of chemical additives on the oil recovery efficiency of microbial formulations. This report describes experiments relating to the effects of additives on oil recovery efficiency of microbial formulations. The effects of additives on the oil recovery efficiency of microbial formulations were determined by conducting oil displacement experiments in 1-foot-long Berea sandstone cores. Sodium tripolyphosphate (STPP), a low-molecular-weight polyacrylamide polymer, a lignosulfonate surfactant, and sodium bicarbonate were added to a microbial formulation at a concentration of 1%. The effects of using these additives in a preflush prior to injection of the microbial formulation were also evaluated. Oil-displacement experiments with and without a sodium bicarbonate preflush were conducted in 4-foot-long Berea sandstone cores, and samples of in situ fluids were collected at various times at four intermediate points along the core. The concentrations of metabolic products and microbes in the fluid samples were determined. 9 refs., 22 figs., 8 tabs.

  11. Interpretation of light scattering and turbidity measurements in aggregated systems: effect of intra-cluster multiple-light scattering.

    PubMed

    Soos, Miroslav; Lattuada, Marco; Sefcik, Jan

    2009-11-12

    In this work we studied the effect of intracluster multiple-light scattering on the scattering properties of a population of fractal aggregates. To do so, experimental data of diffusion-limited aggregation for three polystyrene latexes with similar surface properties but different primary particle diameters (equal to 118, 420, and 810 nm) were obtained by static light scattering and by means of a spectrophotometer. In parallel, a population balance equation (PBE) model, which takes into account the effect of intracluster multiple-light scattering by solving the T-matrix and the mean-field version of T-matrix, was formulated and validated against time evolution of the root mean radius of gyration, , of the zero angle intensity of scattered light, I(0), and of the turbidity, tau. It was found that the mean-field version of the T-matrix theory is able to correctly predict the time evolution of all measured light scattering quantities for all sizes of primary particles without any adjustable parameter. The structure of the aggregates, characterized by fractal dimension, d(f), was independent of the primary particle size and equal to 1.7, which is in agreement with values found in literature. Since the mean-field version of the T-matrix theory used is rather complicated and requires advanced knowledge of cluster structure (i.e., the particle-particle correlation function), a simplified version of the light scattering model was proposed and tested. It was found that within the range of operating conditions investigated, the simplified version of the light scattering model was able to describe with reasonable accuracy the time evolution of all measured light scattering quantities of the cluster mass distribution (CMD) for all three sizes of primary particles and two values of the laser wavelength. PMID:19845324

  12. Cost effective flat plate photovoltaic modules using light trapping

    NASA Technical Reports Server (NTRS)

    Bain, C. N.; Gordon, B. A.; Knasel, T. M.; Malinowski, R. L.

    1981-01-01

    Work in optical trapping in 'thick films' is described to form a design guide for photovoltaic engineers. A thick optical film can trap light by diffusive reflection and total internal reflection. Light can be propagated reasonably long distances compared with layer thicknesses by this technique. This makes it possible to conduct light from inter-cell and intra-cell areas now not used in photovoltaic modules onto active cell areas.

  13. Green light effects on biological systems: a new biophysical phenomenon.

    PubMed

    Comorosan, Sorin; Kappel, Wilhelm; Constantinescu, Ileana; Gheorghe, Marin; Ionescu, Elena; Pîrvu, Cristian; Cinca, Sabin; Cristache, Ligia

    2009-08-01

    This paper reports a new phenomenon connected with the influence of green light (GL) on biological systems. Our experiments have revealed an antioxidant effect of GL on cells subjected to lethal doses of UV at the cellular level and a protective effect of GL on DNA denatured by UV, coupled with a structural modification of DNA macromolecules under GL irradiation, at the molecular level. Mouse melanocyte cultures are subjected to UV irradiations with L(50) fluxes of 16.0 J m(-2) s(-1). GL is obtained from a strontium aluminate pigment, which emits GL under UV activation. Cells grown in GL, prior to UV irradiation, present a clear surprising protective effect with surviving values close to the controls. A GL antioxidant effect is suggested to be mediated through GL influence on cellular water cluster dynamics. To test this hypothesis, reactive oxygen species (ROS) are determined in cell cultures. The results revealed a decrease of cellular ROS generation in the UV-irradiated samples protected by a previous 24 h of GL irradiation. At the DNA level, the same type of GL protection against UV damage is recorded by gel electrophoresis and by UV spectroscopy of the irradiated DNA molecules. Two physical methods, impedance spectroscopy and chronoamperometry, have revealed at the level of GL-irradiated DNA molecules spectral modifications that correlate with the UV spectroscopy results. The interaction between the chargeless photons and the field of water molecules from the cellular compartments is discussed in relation with the new field of macroscopic quantum coherence phenomena. PMID:19669578

  14. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1989-02-04

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used will include S, P, Ag, Cu, Mn, and Na. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of studies including temperature programmed desorption, infrared study of NO adsorption, reactive probing, steady state rate measurement, and transient kinetic study. A better understanding of the role of additive may allow us to use chemical additives to manipulate the catalytic properties of Rh- and Ni-based catalysts for producing high yields of ethanol from syngas. CO insertion is known to be a key step to the formation of acetaldehyde and ethanol from CO hydrogenation over Rh catalysts. Ethylene hydroformylation has often served as a probe to determine CO insertion capabilities of Rh catalysts. The mechanism of CO insertion in ethylene hydroformylation over Rh/SiO{sub 2} was investigated.

  15. Effects of climate on chemical weathering in watersheds

    USGS Publications Warehouse

    White, A.F.; Blum, A.E.

    1995-01-01

    Climatic effects on chemical weathering are evaluated by correlating variations in solute concentrations and fluxes with temperature, precipitation, runoff, and evapotranspiration (ET) for a worldwide distribution of sixty-eight watersheds underlain by granitoid rock types. Stream solute concentrations are strongly correlated with proportional ET loss, and evaporative concentration makes stream solute concentrations an inapprorpiate surrogate for chemical weathering. Chemical fluxes are unaffected by ET, and SiO2 and Na weathering fluxes exhibit systematic increases with precipitation, runoff, and temperature. However, warm and wet watersheds produce anomalously rapid weathering rates. A proposed model that provides an improved prediction of weathering rates over climatic extremes is the product of linear precipitation and Arrhenius temperature functions. The resulting apparent activation energies based on SiO2 and Na fluxes are 59.4 and 62.5 kJ.mol-1, respectively. The coupling between temperature and precipitation emphasizes the importance of tropical regions in global silicate weathering fluxes, and suggests it is not representative to use continental averages for temperature and precipitation in the weathering rate functions of global carbon cycling and climatic change models. Fluxes of K, Ca, and Mg exhibit no climatic correlation, implying that other processes, such as ion exchange, nutrient cycling, and variations in lithology, obscure any climatic signal. -from Authors

  16. The chemical and radiative effects of the Mount Pinatubo eruption

    NASA Technical Reports Server (NTRS)

    Kinneson, Douglas E.; Grant, Keith E.; Connell, Peter S.; Rotman, Douglas A.; Wuebbles, Donald J.

    1994-01-01

    To clarify the mechanisms leading to effects on stratospheric ozone, time-dependent stratospheric aerosol and gas experiment II (SAGE II) and cryogenic limb array elaton spectrometer (CLAES) aerosol optical extinction data and SAGE II surface area density are used as parameters in a two-dimensional (2-D) zonally averaged chemical radiative transport model. The model was integrated with time from before the eruption through December 1993. The modeled impact on global ozone results from increased rates of heterogeneous reactions on sulfate aerosols and from the increased radiative heating and scattering caused by these aerosols. When the aerosol heating is allowed to modify the temperature distribution, the maximum change calculated in equatorial column ozone is -1.6%. The calculated equatorial temperature change and peak local ozone change in October 1991 are +6K and -4%, respectively. When aerosol heating perturbs the circulation in the model, the maximum change in equatorial column ozone is -6%. Increased heterogeneous processing on sulfate aerosols is calculated to have changed equatorial column ozone in late 1991 by -1.5%. Global column ozone in the model in 1992 and 1993 changed by -2.8% and -2.4%, respectively. The relationship of ozone-controlling processes in the lower stratosphere is altered as well; HO(x) becomes the most important catalytic cycle, followed by ClO(x) and NO(x). This is driven by significant changes in trace gas concentrations. In October 1991, lower stratospheric, equatorial NO(x) decreased by 40%, ClO(x) increased by 60%, and HO(x) increased by 25%. When the effect of heterogeneous chemical processing on sulfate aerosols is combined with aerosol heating, modifying either circulation or temperature, dramatically different ozone fingerprints with time and latitude are predicted. Model-derived changes in the equatorial region in column ozone best represented the observed data when perturbed circulation was combined with heterogeneous

  17. Interfacial chemical reaction and multiple gap state formation on three layer cathode in organic light-emitting diode: Ca/BaF{sub 2}/Alq{sub 3}

    SciTech Connect

    Kim, Tae Gun; Kim, Jeong Won; Lee, Hyunbok; Yi, Yeonjin; Lee, Seung Mi

    2015-07-14

    A three layer cathode is a promising stack structure for long lifetime and high efficiency in organic light-emitting diodes. The interfacial chemical reactions and their effects on electronic structures for alkaline-earth metal (Ca, Ba)/Alq{sub 3} [tris(8-hydroxyquinolinato)aluminum] and Ca/BaF{sub 2}/Alq{sub 3} are investigated using in-situ X-ray and ultraviolet photoelectron spectroscopy, as well as molecular model calculation. The BaF{sub 2} interlayer initially prevents direct contact between Alq{sub 3} and the reactive Ca metal, but it is dissociated into Ba and CaF{sub 2} by the addition of Ca. As the Ca thickness increases, the Ca penetrates the interlayer to directly participate in the reaction with the underlying Alq{sub 3}. This series of chemical reactions takes place irrespective of the BaF{sub 2} buffer layer thickness as long as the Ca overlayer thickness is sufficient. The interface reaction between the alkaline-earth metal and Alq{sub 3} generates two energetically separated gap states in a sequential manner. This phenomenon is explained by step-by-step charge transfer from the alkaline-earth metal to the lowest unoccupied molecular orbital states of Alq{sub 3}, forming new occupied states below the Fermi level.

  18. The effect of sterilisation on the light intensity of the reusable Trachlight™.

    PubMed

    Milne, A D; Cave, A L; Brousseau, P A; Hung, O R

    2012-01-01

    We examined the light intensity delivered by the Trachlight™ reusable lightwand and the effect of repeated sterilisation on this light intensity. Using a light meter and test chamber, the light intensity of 12 new Trachlights and 31 Trachlights available in operating theatres was measured. In addition, five new devices underwent 30 repeated sterilisations with light intensity measurement after each cleaning. There was no difference between the light intensity of new Trachlights (median (IQR [range]) 2282 (2202-2780 [1970-4400])) lux and the devices currently in service (2295 (2018-2796 [1649-3280]) lux (p = 0.27)). The median (range) number of uses for devices currently in service was only 3 (0-9). There was, however, significant light intensity loss after 10, 20 and 30 cleanings (p = 0.001). After 10 cleanings, the mean light intensity was 75% of initial output, and after 30 cycles, light intensity was 59% of initial output. PMID:21991929

  19. PM2.5 mass, chemical composition, and light extinction before and during the 2008 Beijing Olympics

    NASA Astrophysics Data System (ADS)

    Li, Xinghua; He, Kebin; Li, Chengcai; Yang, Fumo; Zhao, Qing; Ma, Yongliang; Cheng, Yuan; Ouyang, Wenjuan; Chen, Gangcai

    2013-11-01

    contrast of air quality and visibility before and during the 2008 Beijing Olympic Games provides a rare opportunity to investigate the links between PM2.5 mass, chemical composition, and light extinction in this megacity. Twenty-four hour integrated PM2.5 samples were collected, and light scattering coefficients and the concentrations of black carbon were measured at urban Beijing for this purpose during a measurement campaign from 1 July to 20 September 2008, which was classed into four stages according to the levels of emission control measures. Daily PM2.5 concentrations ranged from 15.9 to 156.7 µg m-3 with an average of 66.0 ± 35.1 µg m-3. The average PM2.5 mass during the Olympics decreased by 49% from the second stage (20 July to 7 August), mainly due to the reduction of secondary inorganic aerosols (i.e., sulfate, nitrate, and ammonium (SNA)). The counterintuitive increase of PM2.5 mass (by 27% on average) during the second stage with two most serious haze episodes, although more rigorous emission control measures were in place, compared to the first stage (1-19 July), was mainly explained by the unfavorable meteorology and input of sulfate aerosols. A daily PM2.5 mass threshold of 50 µg m-3 was extracted for frequent haze occurrence. The extinction fractions of SNA and organic material were each approximately 30% during the 20% best visibility days but changed to 81.7% and 8.4%, respectively, during the 20% worst visibility days. The results indicated that the role of SNA was magnified in haze formation during the 2008 summer in Beijing.

  20. Phosphorylation by protein kinase C of the 20,000-dalton light chain of myosin in intact and chemically skinned vascular smooth muscle.

    PubMed

    Sutton, T A; Haeberle, J R

    1990-02-15

    In the present study we tested the hypothesis that phosphorylation of the 20,000-dalton light chain subunit of smooth muscle myosin (LC20) by the calcium-activated and phospholipid-dependent protein kinase C regulates contraction of chemically-permeabilized (glycerinated) porcine carotid artery smooth muscle. Purified protein kinase C and oleic acid were used to phosphorylate LC20 in glycerinated muscles in the presence of a CaEGTA/EGTA buffer system (pCa 8) to prevent activation of myosin light chain kinase. Phosphorylation of the light chain to 1.3 mol of PO4/mol of LC20 did not stimulate contraction. Tryptic digests of glycerinated carotid artery LC20 contained two major phosphopeptides which contained phosphoserine but not phosphothreonine. Incubation of glycerinated muscles with calcium (20 microM) and calmodulin (10 microM) resulted in contraction and LC20 phosphorylation to 1.1 mol of PO4/mol of LC20; tryptic digests of LC20 from these muscles contained a single phosphopeptide which could be distinguished by phosphopeptide mapping from the two phosphopeptides derived from muscles phosphorylated with protein kinase C. Further phosphorylation of Ca2+/calmodulin-activated muscles to 2.0 mol of PO4/mol of LC20, by incubation with protein kinase C, had no effect on either the level of isometric force or the lightly-loaded shortening velocity (after-load = 0.1 peak active force); removal of Ca2+ and calmodulin, but not protein kinase C and oleic acid, resulted in normal relaxation in spite of maintained phosphorylation to 1.2 mol of PO4/mol of LC20. Comparison of LC20 phosphopeptide maps from glycerinated muscles incubated with protein kinase C plus Ca2+/calmodulin (2.0 mol of PO4/mol of LC20) to maps from intact muscles stimulated with 10(-6) M phorbol 12,13-dibutyrate (0.05 mol of PO4/mol of LC20) showed that the same three phosphopeptides were present in both the intact and glycerinated muscles. These findings show that phosphorylation of LC20 by protein kinase

  1. EFFECTS OF IN SITU LIGHT REDUCTION ON WILD CELERY, VALLISNERIA AMERICANA, IN PERDIDO BAY, AL

    EPA Science Inventory

    The effects of reducing available light using commercially available shade cloth were examined in a densely populated grassbed of wild celery, Vallisneria americana. Grassbeds were shaded in treatments of 92% light reduction and 79% light reduction with control treatments (0% lig...

  2. EFFECTS OF IN SITU LIGHT REDUCTION ON WILD CELERY, VALLISNERIA AMERICANA, IN PERDIDO BAY, ALABAMA

    EPA Science Inventory

    The effects of reducing ambient light using commercially available shade cloth were examined in a densely populated grassbed of wild celerly, Vallisneria americana. Grassbeds were shaded in treatments of 92% light reduction and 79% light reduction with control treatments (0% ligh...

  3. Light-, pH- and thermal-responsive hydrogels with the triple-shape memory effect.

    PubMed

    Xiao, Yao-Yu; Gong, Xiao-Lei; Kang, Yang; Jiang, Zhi-Chao; Zhang, Sheng; Li, Bang-Jing

    2016-08-23

    Light-, pH- and thermal-responsive hydrogels were prepared by introducing dansyl-aggregations and azo-cyclodextrin inclusion complexes as switches. The resulting material showed dual shape memory behavior in response to light, pH or temperature, respectively, and exhibits the triple-shape memory effect in response to light and pH sequentially. PMID:27366796

  4. EVALUATION OF THE EFFECTIVENESS OF CHEMICAL DUST SUPPRESSANTS ON UNPAVED ROADS

    EPA Science Inventory

    The report gives results of measurements of the long-term effectiveness of five unpaved-road chemical dust suppressants. Effectiveness at controlling total particulate emissions in three size fractions was determined over several cycles of chemical application, control effectiven...

  5. CONTINUOUS-FLOW METHOD FOR MEASURING EFFECTS OF CHEMICALS ON SOIL NITRIFICATION

    EPA Science Inventory

    Because the productivity of terrestrial ecosystems is directly related to microbial nutrient cycling, understanding the effects of chemical contaminants on soil microbial processes is important. his study examined the effects of two model chemicals - Roundup (glyphosate) and N-Se...

  6. Effects of Convective Transport on Chemical Signal Propagation in Epithelia

    PubMed Central

    Nebyla, Marek; Přibyl, Michal; Schreiber, Igor

    2012-01-01

    We study effects of convective transport on a chemical front wave representing a signal propagation at a simple (single layer) epithelium by means of mathematical modeling. Plug flow and laminar flow regimes were considered. We observed a nonmonotonous dependence of the propagation velocity on the ligand receptor binding constant under influence of the convective transport. If the signal propagates downstream, the region of high velocities becomes much broader and spreads over several orders of magnitude of the binding constant. When the convective transport is oriented against the propagating signal, either velocity of the traveling front wave is slowed down or the traveling front wave can stop or reverse the direction of propagation. More importantly, chemical signal in epithelial systems influenced by the convective transport can propagate almost independently of the ligand-receptor binding constant in a broad range of this parameter. Furthermore, we found that the effects of the convective transport becomes more significant in systems where either the characteristic dimension of the extracellular space is larger/comparable with the spatial extent of the ligand diffusion trafficking or the ligand-receptor binding/ligand diffusion rate ratio is high. PMID:22404921

  7. Integrated light chemical tagging analyses of seven M31 outer halo globular clusters from the Pan-Andromeda Archaeological Survey

    NASA Astrophysics Data System (ADS)

    Sakari, Charli M.; Venn, Kim A.; Mackey, Dougal; Shetrone, Matthew D.; Dotter, Aaron; Ferguson, Annette M. N.; Huxor, Avon

    2015-04-01

    Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated light spectra taken with the Hobby-Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS) - this paper presents the first determinations of integrated Fe, Na, Mg, Ca, Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target clusters (PA06, PA53, PA54, and PA56) are metal poor ([Fe/H] < -1.5), α-enhanced (though they are possibly less α-enhanced than Milky Way stars at the 1σ level), and show signs of star-to-star Na and Mg variations. The other three globular clusters (H10, H23, and PA17) are more metal rich, with metallicities ranging from [Fe/H] = -1.4 to -0.9. While H23 is chemically similar to Milky Way field stars, Milky Way globular clusters, and other M31 clusters, H10 and PA17, have moderately low [Ca/Fe], compared to Milky Way field stars and clusters. Additionally, PA17's high [Mg/Ca] and [Ba/Eu] ratios are distinct from Milky Way stars, and are in better agreement with the stars and clusters in the Large Magellanic Cloud. None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS; however, based on their locations, kinematics, metallicities, and detailed abundances, the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream, H10 may be associated with the SW cloud, and PA53 and PA56 may be associated with the eastern cloud.

  8. Light-Emitting Diodes with Hierarchical and Multifunctional Surface Structures for High Light Extraction and an Antifouling Effect.

    PubMed

    Leem, Young-Chul; Park, Jung Su; Kim, Joon Heon; Myoung, NoSoung; Yim, Sang-Youp; Jeong, Sehee; Lim, Wantae; Kim, Sung-Tae; Park, Seong-Ju

    2016-01-13

    Bioinspired hierarchical structures on the surface of vertical light-emitting diodes (VLEDs) are demonstrated by combining a self-assembled dip-coating process and nanopatterning transfer method using thermal release tape. This versatile surface structure can efficiently reduce the total internal reflection and add functions, such as superhydrophobicity and high oleophobicity, to achieve an antifouling effect for VLEDs. PMID:26573888

  9. Effects of full-spectrum lighting in submarines. Interim report

    SciTech Connect

    Luria, S.M.

    1987-04-09

    Crewmen on a nuclear submarine were monitored during two patrols, one during which the submarine was lighted with standard fluorescent lights and a second during which it was equipped with full-spectrum lights whose spectral distribution is much more similar to sunlight and emit a greater amount of high-energy ultraviolet light. The levels of 25-OH vitamin D in their blood was measured at the start and during the sixth week of each patrol. In addition, the men kept daily logs during the patrols noting such things as their health and mood. There was no evidence that the full-spectrum lights prevent the typical decline of vitamin D levels in the blood during a patrol. However, the initial levels of vitamin D in the blood were quite different, and it is difficult to interpret the results. The men preferred the full-spectrum light and rated their health as being better under this light, but this was not accompanied by higher ratings of mood or quality of sleep.

  10. Daytime light exposure: effects on biomarkers, measures of alertness, and performance.

    PubMed

    Sahin, Levent; Wood, Brittany M; Plitnick, Barbara; Figueiro, Mariana G

    2014-11-01

    Light can elicit an alerting response in humans, independent from acute melatonin suppression. Recent studies have shown that red light significantly increases daytime and nighttime alertness. The main goal of the present study was to further investigate the effects of daytime light exposure on performance, biomarkers and measures of alertness. It was hypothesized that, compared to remaining in dim light, daytime exposure to narrowband long-wavelength (red) light or polychromatic (2568K) light would induce greater alertness and shorter response times. Thirteen subjects experienced three lighting conditions: dim light (<5lux), red light (λmax=631nm, 213lux, 1.1W/m(2)), and white light (2568K, 361lux, 1.1W/m(2)). The presentation order of the lighting conditions was counterbalanced across the participants and each participant saw a different lighting condition each week. Our results demonstrate, for the first time, that red light can increase short-term performance as shown by the significant (p<0.05) reduced response time and higher throughput in performance tests during the daytime. There was a significant decrease (p<0.05) in alpha power and alpha-theta power after exposure to the white light, but this alerting effect did not translate to better performance. Alpha power was significantly reduced after red light exposure in the middle of the afternoon. There was no significant effect of light on cortisol and alpha amylase. The present results suggest that red light can be used to increase daytime performance. PMID:25131505

  11. Effects of chemical treatments on fresh-cut papaya.

    PubMed

    Albertini, Silvana; Lai Reyes, Andrés Enrique; Trigo, Juliana Moreno; Sarriés, Gabriel Adrián; Spoto, Marta Helena Fillet

    2016-01-01

    Four treatments (control, 0.1% cinnamaldehyde, 0.75% calcium chloride and combination of 0.1% cinnamaldehyde and 0.75% calcium chloride) were used to evaluate chemical effects on shelf life, quality and sensory acceptability of fresh-cut papaya (Carica papaya L.). Papaya slices were packed and covered with polypropylene film, stored at 5 °C; and evaluated after 1, 3, 6, 9, 12, and 15 days for microbiological and physicochemical changes. A sensory evaluation was performed at 1, 3, 6, 9, and 12 days. There was no occurrence of Salmonella, Escherichia coli or psychotropic bacteria. The cinnamaldehyde alone and a combination of cinnamaldehyde and calcium chloride treatments yielded better control of the total coliforms. The combination treatment decreased the CO2 concentration and increased the maintenance of papaya firmness. All the treatments had acceptability. The combination treatment was the most effective treatment for flavor, taste, and preservation until day 12. PMID:26213093

  12. Effects of light intensity light quality and air velocity on temperature in plant reproductive organs

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Hirai, H.

    Excess temperature increase in plant reproductive organs such as anthers and stigmata could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions in closed plant growth facilities There is a possibility that the aberration was caused by an excess increase in temperatures of reproductive organs in Bioregenerative Life Support Systems under microgravity conditions in space The fundamental study was conducted to know the thermal situation of the plant reproductive organs as affected by light intensity light quality and air velocity on the earth and to estimate the excess temperature increase in the reproductive organs in closed plant growth facilities in space Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at an air temperature of 10 r C The temperatures in flowers at 300 mu mol m -2 s -1 PPFD under the lights from red LEDs white LEDs blue LEDs fluorescent lamps and incandescent lamps increased by 1 4 1 7 1 9 6 0 and 25 3 r C respectively for rice and by 2 8 3 4 4 1 7 8 and 43 4 r C respectively for strawberry The flower temperatures increased with increasing PPFD levels The temperatures in petals anthers and stigmas of strawberry at 300 mu mol m -2 s -1 PPFD under incandescent lamps increased by 32 7 29 0 and 26 6 r C respectively at 0 1 m s -1 air velocity and by 20 6 18 5 and 15 9 r C respectively at 0 8 m s -1 air velocity The temperatures of reproductive organs decreased with increasing

  13. An investigation into particle shape effects on the light scattering properties of mineral dust aerosol

    NASA Astrophysics Data System (ADS)

    Meland, Brian Steven

    Mineral dust aerosol plays an important role in determining the physical and chemical equilibrium of the atmosphere. The radiative balance of the Earth's atmosphere can be affected by mineral dust through both direct and indirect means. Mineral dust can directly scatter or absorb incoming visible solar radiation and outgoing terrestrial IR radiation. Dust particles can also serve as cloud condensation nuclei, thereby increasing albedo, or provide sites for heterogeneous reactions with trace gas species, which are indirect effects. Unfortunately, many of these processes are poorly understood due to incomplete knowledge of the physical and chemical characteristics of the particles including dust concentration and global distribution, as well as aerosol composition, mixing state, and size and shape distributions. Much of the information about mineral dust aerosol loading and spatial distribution is obtained from remote sensing measurements which often rely on measuring the scattering or absorption of light from these particles and are thus subject to errors arising from an incomplete understanding of the scattering processes. The light scattering properties of several key mineral components of atmospheric dust have been measured at three different wavelengths in the visible. In addition, measurements of the scattering were performed for several authentic mineral dust aerosols, including Saharan sand, diatomaceous earth, Iowa loess soil, and palagonite. These samples include particles that are highly irregular in shape. Using known optical constants along with measured size distributions, simulations of the light scattering process were performed using both Mie and T-Matrix theories. Particle shapes were approximated as a distribution of spheroids for the T-Matrix calculations. It was found that the theoretical model simulations differed markedly from experimental measurements of the light scattering, particularly near the mid-range and near backscattering angles. In

  14. Marine organics effect on sea-spray light scattering

    NASA Astrophysics Data System (ADS)

    Vaishya, Aditya; Ovadnevaite, Jurgita; Bialek, Jakub; Jennings, S. G.; Ceburnis, Darius; O'Dowd, Colin

    2013-05-01

    Primary-produced sea-spray is typically composed of sea-salt, but in biologically-active regions, the spray can become enriched with organic matter which reduces hygroscopicity of sea-spray, thereby having a potential impact on aerosol scattering. This study shows that scattering enhancement of marine aerosol, as a function of increasing relative humidity, is reduced when enriched with organics whose results are used to develop a new hygroscopicity growth-factor parameterization for sea-spray enriched in organic matter. The parameterization reveals a dual state which flips from high-hygroscopicity and high-scattering enhancement to low-hygroscopicity and low-scattering enhancement as the organic volume fraction increases from below ˜ 0.55 to above ˜ 0.55. In terms of organic enrichment, the effect on Top of Atmosphere (TOA) direct radiative forcing (ΔF) is to reduce the cooling contribution of sea-spray by ˜ 5.5 times compared to pure sea-salt spray. The results presented here highlight a significant coupling between the marine biosphere and the direct radiative budget through alteration of sea-spray chemical composition, potentially leading to accelerated global warming should biological activity increase with future projected temperature increases.

  15. Effects of nitrogen-related defects on visible light photocatalytic response in N+ implanted TiO2: A first-principles study

    NASA Astrophysics Data System (ADS)

    Senga, Junya; Tatsumi, Kazuyoshi; Muto, Shunsuke; Yoshida, Tomoko

    2015-09-01

    It was found that the visible-light responsiveness of a nitrogen ion-implanted TiO2 photocatalyst was attributable to the predominant chemical states of nitrogen, depending on the local nitrogen concentration near the surface. In the present study, we examined the effects of conceivable nitrogen-related defects on the visible light responsiveness, based on electronic structures calculated from first principles. Possible chemical states were proposed by comparing previously reported experiments with the present theoretical N-K X-ray absorption spectra. The theoretically predicted visible light absorption spectra and carrier trap states due to the bandgap states associated with the defects well explained the relationship between the catalytic reactivity and the proposed chemical states.

  16. Effects of nitrogen-related defects on visible light photocatalytic response in N{sup +} implanted TiO{sub 2}: A first-principles study

    SciTech Connect

    Senga, Junya; Tatsumi, Kazuyoshi Muto, Shunsuke; Yoshida, Tomoko

    2015-09-21

    It was found that the visible-light responsiveness of a nitrogen ion-implanted TiO{sub 2} photocatalyst was attributable to the predominant chemical states of nitrogen, depending on the local nitrogen concentration near the surface. In the present study, we examined the effects of conceivable nitrogen-related defects on the visible light responsiveness, based on electronic structures calculated from first principles. Possible chemical states were proposed by comparing previously reported experiments with the present theoretical N-K X-ray absorption spectra. The theoretically predicted visible light absorption spectra and carrier trap states due to the bandgap states associated with the defects well explained the relationship between the catalytic reactivity and the proposed chemical states.

  17. Effect of light-exposure duration on the amount of leachable monomers from light-activated reline material.

    PubMed

    Kawaguchi, M; Takahashi, Y; Fukushima, T; Habu, T

    1996-02-01

    Leaching of monomers from light-activated direct intraoral reline material (Lebaron LC) was determined by means of high-pressure liquid chromatography analysis. This study evaluated the effects of exposure duration and thickness to determine appropriate curing conditions that reduce the levels of unreacted monomeric components. Prolonged duration of exposure (30 minutes) reduced the amount of leached monomer. However, the results of this study indicated that the amount of leached monomeric components increased with an increasing reline material thickness. The results suggest that the light-activated reline material should be cured for sufficient prolonged exposure duration. PMID:8667278

  18. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Podhorodecki, A.; Zatryb, G.; Misiewicz, J.; Wojcik, J.; Wilson, P. R. J.; Mascher, P.

    2012-11-01

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  19. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition.

    PubMed

    Podhorodecki, A; Zatryb, G; Misiewicz, J; Wojcik, J; Wilson, P R J; Mascher, P

    2012-11-30

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature. PMID:23110801

  20. Selective antagonistic effects of exposure to bright light on the hypothermic action of ethanol.

    PubMed

    Overstreet, D H; Dilsaver, S C; Rezvani, A H; Janowsky, D S

    1990-01-01

    Flinders Sensitive and Resistant Lines of rats, which are differentially sensitive to the hypothermic effects of both muscarinic agonists and ethanol, were exposed to full spectrum artificial bright light for eight days, because exposure to bright light has been shown to blunt hypothermic responses to muscarinic agonists. There was a selective blunting of the hypothermic effects of ethanol, but no significant change in the intoxicating effects of ethanol, as measured by evaluation of the righting reflex. The selective effect of exposure to bright light on the hypothermic actions of ethanol suggests that bright light may be modifying the function of only a limited number of brain regions, including the hypothalamus. PMID:2085349

  1. Berkeley Accelerator Space Effects (BASE) Light Ion FacilityUpgrade

    SciTech Connect

    Johnson, Michael B.; McMahan, Margaret A.; Gimpel, Thomas L.; Tiffany, William S.

    2006-07-07

    The BASE Light Ion Facility upgrades have been completed. All proton beams are now delivered to Cave 4A. New control software, a larger diameter beam window, and improved quality assurance measures have been added.

  2. Diffusion filter eliminates fringe effects of coherent laser light source

    NASA Technical Reports Server (NTRS)

    Olsasky, M. J.

    1970-01-01

    Diffusion filter comprised of small particles in colloidal suspension reduces the coherence of a laser beam used as a photographic light source. Interference patterns which obscure details in photographic film are eliminated, the intensity and collimation are moderately affected.

  3. Paterno`-Bu¨chi Reaction as a Demonstration of Chemical Kinetics and Synthetic Photochemistry Using a Light Emitting Diode Apparatus

    ERIC Educational Resources Information Center

    Thompson, Matthew P.; Agger, Jonathan; Wong, Lu Shin

    2015-01-01

    The Paterno`-Bu¨chi photocycloaddition reaction is used as the basis for physical-organic final-year undergraduate laboratory experiments designed to emphasize the multidisciplinary approach to modern-day chemical practice. These reactions are performed using commercially available LED-based light sources, which offer a convenient and safe tool…

  4. A comparative study of blue, green and yellow light emitting diode structures grown by metal organic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Ramaiah, Kodigala Subba; Su, Y. K.; Chang, S. J.; Chen, C. H.

    2006-02-01

    The blue, green and yellow light emitting diode (LED) structures have been fabricated by metal organic chemical vapor deposition (MOCVD), and characterized by using different techniques, in order to understand the mechanism between these LEDs. Atomic force microscopy (AFM) analysis revealed that the surface roughness value and density of etch pits were different in the blue, green and yellow LEDs. The threading, misfit dislocations, interfacial dislocations, nano-pipe-like structures and quantum dot-like structures, which determine quality of the structures, were observed by transmission electron microscope (TEM) in the LED structures. The reasons for their formation in the layers are now elucidated. The indium composition, period width such as well and barrier widths were determined by simulating experimental high resolution X-ray diffraction (HRXRD) spectra. The In composition obtained by HRXRD and photoluminescence (PL) measurements for the same LED structure was not one and the same due to several reasons. In fact, the InGaN quantum well emission peaks at 2.667 and 2.544 eV of the blue and green LEDs, respectively showed S-shaped character shift, whereas the quantum well peak at 2.219 eV of yellow LEDs did not show any shift in the PL spectra with decreasing temperature. The blue, green and yellow LEDs showed different activation energies.

  5. Chemical analysis and ozone formation potential of exhaust from dual-fuel (liquefied petroleum gas/gasoline) light duty vehicles

    NASA Astrophysics Data System (ADS)

    Adam, T. W.; Astorga, C.; Clairotte, M.; Duane, M.; Elsasser, M.; Krasenbrink, A.; Larsen, B. R.; Manfredi, U.; Martini, G.; Montero, L.; Sklorz, M.; Zimmermann, R.; Perujo, A.

    2011-06-01

    Measures must be undertaken to lower the transport sector's contribution to anthropogenic emissions. Vehicles powered by liquefied petroleum gas (LPG) are an option due to their reduced emissions of air pollutants compared to engines with conventional fuels. In the present study, ten different dual-fuel LPG/gasoline light duty vehicles were tested, which all complied with European emission level legislation EURO-4. Tests with LPG and gasoline were performed on a chassis dynamometer by applying the New European Driving Cycle (NEDC) and emission factors and ozone formation potentials of both kinds of fuels were compared. The components investigated comprised regulated compounds, CO 2, volatile hydrocarbons and carbonyls. On-line analysis of aromatic species was carried out by resonance-enhanced multiphoton ionization-time-of-flight mass spectrometry (REMPI-TOFMS). We demonstrate that utilization of LPG can entail some environmental benefits by reducing emissions. However, for dual-fuel LPG/gasoline vehicles running on LPG the benefits are less than expected. The main reason is that dual-fuel vehicles usually start the engine up on gasoline even when LPG is selected as fuel. This cold-start phase is crucial for the quality of the emissions. Moreover, we demonstrate an influence on the chemical composition of emissions of vehicle performance, fuel and the evaporative emission system of the vehicles.

  6. Removal and fate of endocrine disruptors chemicals under lab-scale postreatment stage. Removal assessment using light, oxygen and microalgae.

    PubMed

    Abargues, M R; Ferrer, J; Bouzas, A; Seco, A

    2013-12-01

    The aim of this study was to assess the effect of light, oxygen and microalgae on micropollutants removal. The studied micropollutants were 4-(1,1,3,3-tetramethylbutyl)phenol (OP), technical-nonylphenol (t-NP), 4-n-nonylphenol (4-NP), Bisphenol-A (BPA). In order to study the effect of the three variables on the micropollutants removal, a factorial design was developed. The experiments were carried out in four batch reactors which treated the effluent of an anaerobic membrane bioreactor. The gas chromatography mass spectrometry was used for the measurement of the micropollutants. The results showed that light, oxygen and microalgae affected differently to the degradation ratios of each micropollutant. The results showed that under aerated conditions removal ratios higher than 91% were achieved, whereas for non-aerated conditions the removal ratios were between 50% and 80%, except for 4-NP which achieved removal ratios close to 100%. Besides, mass balance showed that the degradation processes were more important than the sorption processes. PMID:24096281

  7. Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands National Park, St. John, U.S. Virgin Islands

    USGS Publications Warehouse

    Bargar, Timothy A.; Alvarez, David; Garrison, Virginia H.

    2015-01-01

    Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and the sea surface microlayer (SML) were also examined. The UV filter chemicals 4-methylbenzylidene camphor, benzophenone-3, octinoxate, homosalate, and octocrylene were detected at concentrations up to 6073 ng/L (benzophenone-3). Concentrations for benzophenone-3 and homosalate declined exponentially (r2 = 0.86 to 0.98) with distance from the beach. Limited data indicate that some UV filter chemicals may partition to the SML relative to the subsurface waters. Contamination of VINP coastal waters by UV filter chemicals may be a significant issue, but an improved understanding of the temporal and spatial variability of their concentrations would be necessary to better understand the risk they present.

  8. Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands national park, St. John, U.S. Virgin Islands.

    PubMed

    Bargar, Timothy A; Alvarez, David A; Garrison, Virginia H

    2015-12-15

    Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and the sea surface microlayer (SML) were also examined. The UV filter chemicals 4-methylbenzylidene camphor, benzophenone-3, octinoxate, homosalate, and octocrylene were detected at concentrations up to 6073 ng/L (benzophenone-3). Concentrations for benzophenone-3 and homosalate declined exponentially (r(2)=0.86 to 0.98) with distance from the beach. Limited data indicate that some UV filter chemicals may partition to the SML relative to the subsurface waters. Contamination of VINP coastal waters by UV filter chemicals may be a significant issue, but an improved understanding of the temporal and spatial variability of their concentrations would be necessary to better understand the risk they present. PMID:26581812

  9. New chemical evolution analytical solutions including environment effects

    NASA Astrophysics Data System (ADS)

    Spitoni, E.

    2015-07-01

    In the last years, more and more interest has been devoted to analytical solutions, including inflow and outflow, to study the metallicity enrichment in galaxies. In this framework, we assume a star formation rate which follows a linear Schmidt law, and we present new analytical solutions for the evolution of the metallicity (Z) in galaxies. In particular, we take into account environmental effects including primordial and enriched gas infall, outflow, different star formation efficiencies and galactic fountains. The enriched infall is included to take into account galaxy-galaxy interactions. Our main results can be summarized as: (i) when a linear Schmidt law of star formation is assumed, the resulting time evolution of the metallicity Z is the same either for a closed-box model or for an outflow model. (ii) The mass-metallicity relation for galaxies which suffer a chemically enriched infall, originating from another evolved galaxy with no pre-enriched gas, is shifted down in parallel at lower Z values, if compared to the closed box model. (iii) When a galaxy suffers at the same time a primordial infall and a chemically enriched one, the primordial infall always dominates the chemical evolution. (iv) We present new solutions for the metallicity evolution in a galaxy which suffers galactic fountains and an enriched infall from another galaxy at the same time. The analytical solutions presented here can be very important to study the metallicity (oxygen), which is measured in high-redshift objects. These solutions can be very useful: (a) in the context of cosmological semi-analytical models for galaxy formation and evolution, and (b) for the study of compact groups of galaxies.

  10. Effects of scalp dermatitis on chemical property of hair keratin

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Sook; Shin, Min Kyung; Park, Hun-Kuk

    2013-05-01

    The effects of scalp dermatitis (seborrheic dermatitis (SD), psoriasis, and atopic dermatitis (AD)) on chemical properties of hair keratin were investigated by Fourier transform infrared (FT-IR) spectroscopy. Hairs were collected from lesional regions affected by SD, psoriasis, and AD and non-lesional regions separately. The hairs with SD were taken from patients with ages of 16-80 years. The ages of patients with psoriasis ranged from 8 to 67 years, and all patients exhibited moderate disease. Hairs with AD were taken from the patients with ages of 24-45 years and the average SCORing atopic dermatitis (SCORAD) was 48.75. Hairs from 20 normal adults were collected as a control. The FT-IR absorbance bands were analyzed by the Gaussian model to obtain the center frequency, half width, height, and area of each band. The height and area of all bands in the spectra were normalized to the amide I centered at 1652 cm-1 to quantitatively analyze the chemical composition of keratin. The spectra of hair with scalp dermatitis were different with that of control, the amide A components centered at 3278 cm-1 were smaller than those of the control. The psoriasis hair showed a large difference in the IR absorbance band between lesional and non-lesional hairs indicating good agreement with the morphological changes. The hairs with diseases did not show differences in the content of cystine, which was centered at 1054 cm-1, from the control. The chemical properties of keratin were not significantly different between the hairs affected by SD, psoriasis, and AD. However, the changes induced by scalp dermatitis were different with weathering. Therefore, FT-IR analysis could be used to screen differences between the physiological and pathological conditions of scalp hair.

  11. Light shift effects in the Rb-87 maser

    NASA Technical Reports Server (NTRS)

    Busca, G.; Tetu, M.; Vanier, J.

    1973-01-01

    Previous work has shown the possibility to overcome the dependence of the Rb-87 maser frequency on light intensity by tuning the cavity at a proper setting. The conditions for this setting, called the light-independent frequency setting (LIFS), are carefully investigated. The results presented prove the existence of the LIFS and provide a new criterion for an automatic cavity tuning of the Rb maser.

  12. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    NASA Astrophysics Data System (ADS)

    Gupta, Susanta K. Sen

    2015-12-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma-liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining.

  13. Effect of UV-C light on the microbial and sensory quality of seasoned dried seafood.

    PubMed

    Lee, Eun-Seon; Park, Shin Young; Ha, Sang-Do

    2016-04-01

    This study investigated the effects of different doses of UV-C light at 253.7 nm (0-18 kJ/m(2)) on the reduction of Escherichia coli,Staphylococcus aureus and Bacillus cereus in contaminated seasoned dried filefish (Thamnaconus modestus) and sliced squid (Todarodes pacificus) surfaces and sensory quality. The counts of all three bacteria were significantly (P < 0.05) reduced by the increase of UV-C dosage.E. coli,S. aureus and B. cereus on filefish with 18 kJ/m(2)of UV-C maximally reduced by 2.70, 2.55 and 2.57 log CFU/g, respectively; however, on the sliced squid using the same UV dose reduced the same bacteria by 1.35, 0.54 and 1.05 log CFU/g, respectively. However, the results suggest that 6 to 9 kJ/m(2)of UV-C could be used for the inactivation of E. coli and B. cereus in these dried fishery products without any changes in sensory quality. However, S. aureus levels on sliced squid will require a combination of UV-C light and chemical treatment. PMID:25967394

  14. Realization of effective light trapping and omnidirectional antireflection in smooth surface silicon nanowire arrays.

    PubMed

    Xie, W Q; Oh, J I; Shen, W Z

    2011-02-11

    We have successfully fabricated well-ordered silicon nanowire (SiNW) arrays of smooth surface by using a low-cost and facile Ag-assisted chemical etching technique. We have experimentally found that the reflectance can be significantly suppressed (<1%) over a wide solar spectrum (300-1000 nm) in the as-grown samples. Also, based on our bundled model, we have used rigorous coupled-wave analysis to simulate the reflectance in SiNW arrays, and found that the calculated results are in good agreement with the experimental data. From a further simulation study on the light absorption in SiNW arrays, we have obtained a photocurrent enhancement of up to 425% per unit volume of material as compared to crystalline Si, implying that effective light trapping can be realized in the as-grown samples. In addition, we have demonstrated experimentally and theoretically that the as-grown samples have an omnidirectional high-efficiency antireflection property. PMID:21212474

  15. Effect of Lysine Modification on the Stability and Cellular Binding of Human Amyloidogenic Light Chains

    SciTech Connect

    O'Neill, Hugh Michael; Davern, Sandra M.; Murphy, Charles L.; Wall, Jonathan; Deborah, Weiss T.; Solomon, Alan

    2011-01-01

    AL amyloidosis is characterized by the pathologic deposition as fibrils of monoclonal light chains (i.e., Bence Jones proteins [BJPs]) in particular organs and tissues. This phenomenon has been attributed to the presence in amyloidogenic proteins of particular amino acids that cause these molecules to become unstable, as well as post-translational modifications and, in regard to the latter, we have investigated the effect of biotinylation of lysyl residues on cell binding. We utilized an experimental system designed to test if BJPs obtained from patients with AL amyloidosis or, as a control, multiple myeloma (MM), bound human fibroblasts and renal epithelial cells. As documented by fluorescent microscopy and ELISA, the amyloidogenic BJPs, as compared with MM components, bound preferentially and this reactivity increased significantly after chemical modification of their lysyl residues with sulfo-NHS-biotin. Further, based on tryptophan fluorescence and circular dichorism data, it was apparent that their conformation was altered, which we hypothesize exposed a binding site not accessible on the native protein. The results of our studies indicate that post-translational structural modifications of pathologic light chains can enhance their capacity for cellular interaction and thus may contribute to the pathogenesis of AL amyloidosis and multiple myeloma.

  16. Transient optical angular momentum effects in light-matter interactions

    NASA Astrophysics Data System (ADS)

    Carter, A. R.; Babiker, M.; Al-Amri, M.; Andrews, D. L.

    2005-10-01

    The time evolution of the radiation pressure forces due to the action of laser light on matter in the form of neutral molecules, atoms, and ions is considered when the frequency of the light is comparable to a dipole-allowed transition frequency. We find that the transient regime, applicable from the instant the laser is switched on, is important for the gross motion, provided that the upper-state lifetime Γ-1 is relatively long, while the steady-state regime, formally such that t≫ Γ-1 , is appropriate for the evaluation of the forces and the dynamics for large Γ . With a focus on the orbital-angular-momentum-endowed laser light, the light-induced time-dependent forces and torques are determined and their full time dependence utilized to determine trajectories. Marked differences are found in both translational and rotational features in comparison with the results emerging when the steady-state forces are assumed from the outset. Intricate and detailed atom trajectories are plotted for Laguerre-Gaussian light at near resonance for a transition of Eu3+ that has a particularly small Γ . The implications of the results for trapping and manipulating atoms and ions using laser light are pointed out and discussed.

  17. Sensitivity of feedback effects in CBMZ/MOSAIC chemical mechanism

    NASA Astrophysics Data System (ADS)

    San José, R.; Pérez, J. L.; Balzarini, A.; Baró, R.; Curci, G.; Forkel, R.; Galmarini, S.; Grell, G.; Hirtl, M.; Honzak, L.; Im, U.; Jiménez-Guerrero, P.; Langer, M.; Pirovano, G.; Tuccella, P.; Werhahn, J.; Žabkar, R.

    2015-08-01

    To investigate the impact of the aerosol effects on meteorological variables and pollutant concentrations two simulations with the WRF-Chem model have been performed over Europe for year 2010. We have performed a baseline simulation without any feedback effects and a second simulation including the direct as well as the indirect aerosol effect. The paper describes the full configuration of the model, the simulation design, special impacts and evaluation. Although low aerosol particle concentrations are detected, the inclusion of the feedback effects results in an increase of solar radiation at the surface over cloudy areas (North-West, including the Atlantic) and decrease over more sunny locations (South-East). Aerosol effects produce an increase of the water vapor and decrease the planet boundary layer height over the whole domain except in the Sahara area, where the maximum particle concentrations are detected. Significant ozone concentrations are found over the Mediterranean area. Simulated feedback effects between aerosol concentrations and meteorological variables and on pollutant distributions strongly depend on the aerosol concentrations and the clouds. Further investigations are necessary with higher aerosol particle concentrations. WRF-Chem variables are evaluated using available hourly observations in terms of performance statistics. Standardized observations from the ENSEMBLE system web-interface were used. The research was developed under the second phase of Air Quality Model Evaluation International Initiative (AQMEII). WRF-Chem demonstrates its capability in capturing temporal and spatial variations of the major meteorological variables and pollutants, except the wind speed over complex terrain. The wind speed bias may affect the accuracy in the chemical predictions (NO2, SO2). The analysis of the correlations between simulated data sets and observational data sets indicates that the simulation with aerosol effects performs slightly better. These

  18. [Effects of different LED light qualities on growth, photosynthetic characteristics and nutritional quality of savoy].

    PubMed

    Chen, Xiang-Wei; Liu, Shi-Qi; Wang, Yue; Liu, Jing-Kai; Feng, Lei

    2014-07-01

    LED lighting has several unique advantages over traditional lighting, including the ability to control spectral composition, the ability to produce very high light levels with low radiant heat output when cooled properly, and the ability to maintain useful light output for years without replacement. LED light sources have the capability of controlling true spectral composition, allowing wavelengths to match plant photoreceptors to provide more optimal production to regulate plant morphology and nutritional quality. In this paper, the effects of different light qualities on the growth, photosynthetic response and nutritional quality of savoy were studied. With 'Juhua-Xiaobaye' savoy as the test plant, full red light, full blue light, red/blue (3/1) light, red/blue (7/1) light and white/red/blue (3/2/1) light generated by light-emitting diodes were applied with white light generated by fluorescent lamps as control. The results showed that red light could increase biomass and stem diameter, but blue light showed the opposite effect. The chlorophyll (a+b) content was the highest in the red/blue (7/1) light treatment, and chlorophyll (a+b) content was correlated with the red/blue ratio positively. Blue light decreased chlorophyll (a + b) content of savoy, and increased chlorophyll a/b. The photosynthetic rate (Pn) and transpiration rate under red light were the highest, and increased by 43.8% and 55.1% compared with the control. Intercellular CO2 concentration and conductance were the highest under blue light. The fluorescence parameters of the plant were significantly affected by light quality. Values of the maximal photochemical efficiency of PS II (Fv/Fm), Fv/Fo and Phi(PS II) were the highest under white light. Soluble sugar, soluble protein and vitamin C contents were the highest under red, blue and white light, respectively. Comprehensive analysis indicated that red/blue (7/1) light was the best light combination to increase leaf chlorophyll (a+b) content and net

  19. Lau Effect: AN Interference Phenomenon in Partially Coherent Light.

    NASA Astrophysics Data System (ADS)

    Sudol, Ronald J.

    for discussing the observed intensity patterns in the partially coherent experiment. Experiments are performed to test the theory. Finally, two applications of the Lau effect are examined. The first is a shearing-type interferometer which demonstrates the sampling nature of the grating structures. The second employs the Lau experiment as a method for detecting low frequency object periodicity. Limits for the applicability of this technique are investigated. Recognizing that each of these applications involves wavefront sampling with finite apertures, the effect of finite sampling apertures is examined within the context of two-beam interference of partially coherent light.

  20. Additive Mixture Effects of Estrogenic Chemicals in Human Cell-Based Assays Can Be Influenced by Inclusion of Chemicals with Differing Effect Profiles

    PubMed Central

    Evans, Richard Mark; Scholze, Martin; Kortenkamp, Andreas

    2012-01-01

    A growing body of experimental evidence indicates that the in vitro effects of mixtures of estrogenic chemicals can be well predicted from the estrogenicity of their components by the concentration addition (CA) concept. However, some studies have observed small deviations from CA. Factors affecting the presence or observation of deviations could include: the type of chemical tested; number of mixture components; mixture design; and assay choice. We designed mixture experiments that address these factors, using mixtures with high numbers of components, chemicals from diverse chemical groups, assays with different in vitro endpoints and different mixture designs and ratios. Firstly, the effects of mixtures composed of up to 17 estrogenic chemicals were examined using estrogenicity assays with reporter-gene (ERLUX) and cell proliferation (ESCREEN) endpoints. Two mixture designs were used: 1) a ‘balanced’ design with components present in proportion to a common effect concentration (e.g. an EC10) and 2) a ‘non-balanced’ design with components in proportion to potential human tissue concentrations. Secondly, the individual and simultaneous ability of 16 potential modulator chemicals (each with minimal estrogenicity) to influence the assay outcome produced by a reference mixture of estrogenic chemicals was examined. Test chemicals included plasticizers, phthalates, metals, PCBs, phytoestrogens, PAHs, heterocyclic amines, antioxidants, UV filters, musks, PBDEs and parabens. In all the scenarios tested, the CA concept provided a good prediction of mixture effects. Modulation studies revealed that chemicals possessing minimal estrogenicity themselves could reduce (negatively modulate) the effect of a mixture of estrogenic chemicals. Whether the type of modulation we observed occurs in practice most likely depends on the chemical concentrations involved, and better information is required on likely human tissue concentrations of estrogens and of potential modulators

  1. Effects-based chemical category approach for prioritization of low affinity estrogenic chemicals

    EPA Science Inventory

    Regulatory agencies are charged with addressing the endocrine disrupting potential of a large number of chemicals for which there is often little or no data on which to make decisions. Prioritizing the chemicals of greatest concern for potential hazard to humans and wildlife is a...

  2. Potential effects of environmental chemical contamination in congenital heart disease.

    PubMed

    Gorini, Francesca; Chiappa, Enrico; Gargani, Luna; Picano, Eugenio

    2014-04-01

    There is compelling evidence that prenatal exposures to environmental xenobiotics adversely affect human development and childhood. Among all birth defects, congenital heart disease (CHD) is the most prevalent of all congenital malformations and remains the leading cause of death. It has been estimated that in most cases the causes of heart defects remain unknown, while a growing number of studies have indicated the potential role of environmental agents as risk factors in CHD occurrence. In particular, maternal exposure to chemicals during the first trimester of pregnancy represents the most critical window of exposure for CHD. Specific classes of xenobiotics (e.g. organochlorine pesticides, organic solvents, air pollutants) have been identified as potential risk factors for CHD. Nonetheless, the knowledge gained is currently still incomplete as a consequence of the frequent heterogeneity of the methods applied and the difficulty in estimating the net effect of environmental pollution on the pregnant mother. The presence of multiple sources of pollution, both indoor and outdoor, together with individual lifestyle factors, may represent a further confounding element for association with the disease. A future new approach for research should probably focus on individual measurements of professional, domestic, and urban exposure to physical and chemical pollutants in order to accurately retrace the environmental exposure of parents of affected offspring during the pre-conceptional and pregnancy periods. PMID:24452958

  3. Review of Wildfire Effects on Chemical Water Quality

    SciTech Connect

    Kelly Bitner; Bruce Gallaher; Ken Mullen

    2001-05-01

    The Cerro Grande Fire of May 2000 burned almost 43,000 acres of forested land within the Pajarito Plateau watershed in northern New Mexico. Runoff events after the fire were monitored and sampled by Los Alamos National Laboratory. Changes in the composition of runoff water were noted when compared to runoff water composition of the previous 20 years. In order to understand the chemical water quality changes noted in runoff water after the Cerro Grande Fire, a summary of the reported effects of fire on runoff water chemistry and on soils that contribute to runoff water chemistry was compiled. The focus of this report is chemical water quality, so it does not address changes in sediment transport or water quantity associated with fires. Within the general inorganic parameters, increases of dissolved calcium, magnesium, nitrogen, phosphorus, and potassium and pH in runoff water have been observed as a result of fire. However, the dissolved sodium, carbon, and sulfate have been observed to increase and decrease as a result of fire. Metals have been much less studied, but manganese, copper, zinc, and cesium-137 have been observed to increase as a result of fire.

  4. Environmental chamber studies of atmospheric reactivities of volatile organic compounds: Effects of varying chamber and light source

    SciTech Connect

    Carter, W.; Luo, D.; Malkina, I.; Pierce, J.

    1995-05-01

    Photochemical oxidant models are essential tools for assessing effects of emissions changes on ground-level ozone formation. Such models are needed for predicting the ozone impacts of increased alternative fuel use. The gas-phase photochemical mechanism is an important component of these models because ozone is not emitted directly, but is formed from the gas-phase photochemical reactions of the emitted volatile organic compounds (VOCs) and oxides of nitrogen (NO{sub x}) in air. The chemistry of ground level ozone formation is complex; hundreds of types of VOCs being emitted into the atmosphere, and most of their atmospheric reactions are not completely understood. Because of this, no chemical model can be relied upon to give even approximately accurate predictions unless it has been evaluated by comparing its predictions with experimental data. Therefore an experimental and modeling study was conducted to assess how chemical mechanism evaluations using environmental chamber data are affected by the light source and other chamber characteristics. Xenon arc lights appear to give the best artificial representation of sunlight currently available, and experiments were conducted in a new Teflon chamber constructed using such a light source. Experiments were also conducted in an outdoor Teflon Chamber using new procedures to improve the light characterization, and in Teflon chambers using blacklights. These results, and results of previous runs other chambers, were compared with model predictions using an updated detailed chemical mechanism. The magnitude of the chamber radical source assumed when modeling the previous runs were found to be too high; this has implications in previous mechanism evaluations. Temperature dependencies of chamber effects can explain temperature dependencies in chamber experiments when Ta-300{degree}K, but not at temperatures below that.

  5. Chemical and light absorption properties of humic-like substances from biomass burning emissions under controlled combustion experiments

    NASA Astrophysics Data System (ADS)

    Park, Seung Shik; Yu, Jaemyeong

    2016-07-01

    PM2.5 samples from biomass burning (BB) emissions of three types - rice straw (RS), pine needles (PN), and sesame stems (SS) - were collected through laboratory-controlled combustion experiments and analyzed for the mass, organic and elemental carbon (OC and EC), water-soluble organic carbon (WSOC), humic-like substances (HULIS), and water soluble inorganic species (Na+, NH4+, K+, Ca2+, Mg2+, Cl-, NO3-, SO42-, and oxalate). The combustion experiments were carried out at smoldering conditions. Water-soluble HULIS in BB samples was isolated using a one-step solid phase extraction method, followed by quantification with a total organic carbon analyzer. This study aims to explore chemical and light absorption characteristics of HULIS from BB emissions. The contributions of HULIS (=1.94 × HULIS-C) to PM2.5 emissions were observed to be 29.5 ± 2.0, 15.3 ± 3.1, and 25.8 ± 4.0%, respectively, for RS, PN, and SS smoke samples. Contributions of HULIS-C to OC and WSOC for the RS, PN, and SS burning emissions were 0.26 ± 0.03 and 0.63 ± 0.05, 0.15 ± 0.04 and 0.36 ± 0.08, and 0.29 ± 0.08 and 0.51 ± 0.08, respectively. Light absorption by the water extracts from BB aerosols exhibited strong wavelength dependence, which is characteristic of brown carbon spectra with a sharply increasing absorption as wavelength decreases. The average absorption Ångström exponents (AAE) of the water extracts (WSOC) fitted between wavelengths of 300-400 nm were 8.3 (7.4-9.0), 7.4 (6.2-8.5), and 8.0 (7.1-9.3) for the RS, PN, and SS burning samples, which are comparable to the AAE values of BB samples reported in previous publications (e.g., field and laboratory chamber studies). The average mass absorption efficiencies of WSOC measured at 365 nm (MAE365) were 1.37 ± 0.23, 0.86 ± 0.09, and 1.38 ± 0.21 m2/gṡC for RS, PN, and SS burning aerosols, respectively. Correlations of total WSOC, hydrophilic WSOC (= total WSOC-HULIS-C), and HULIS-C concentrations in solution with the light

  6. Antagonistic and synergistic effects of light irradiation on the effects of copper on Chlamydomonas reinhardtii.

    PubMed

    Cheloni, Giulia; Cosio, Claudia; Slaveykova, Vera I

    2014-10-01

    The present study showed the important role of light intensity and spectral composition on Cu uptake and effects on green alga Chlamydomonas reinhardtii. High-intenisty light (HL) increased cellular Cu concentrations, but mitigated the Cu-induced decrease in chlorophyll fluorescence, oxidative stress and lipid peroxidation at high Cu concentrations, indicating that Cu and HL interact in an antagonistic manner. HL up-regulated the transcription of genes involved in the antioxidant response in C. reinhardtii and thus reduced the oxidative stress upon exposure to Cu and HL. Combined exposure to Cu and UVBR resulted in an increase of cellular Cu contents and caused severe oxidative damage to the cells. The observed effects were higher than the sum of the effects corresponding to exposure to UVBR or Cu alone suggesting a synergistic interaction. PMID:25072593

  7. Chemical Effect on Wellbore Instability of Nahr Umr Shale

    PubMed Central

    Nie, Zhen

    2013-01-01

    Wellbore instability is one of the major problems that hamper the drilling speed in Halfaya Oilfield. Comprehensive analysis of geological and engineering data indicates that Halfaya Oilfield features fractured shale in the Nahr Umr Formation. Complex accidents such as wellbore collapse and sticking emerged frequently in this formation. Tests and theoretical analysis revealed that wellbore instability in the Halfaya Oilfield was influenced by chemical effect of fractured shale and the formation water with high ionic concentration. The influence of three types of drilling fluids on the rock mechanical properties of Nahr Umr Shale is tested, and time-dependent collapse pressure is calculated. Finally, we put forward engineering countermeasures for safety drilling in Halfaya Oilfield and point out that increasing the ionic concentration and improving the sealing capacity of the drilling fluid are the way to keep the wellbore stable. PMID:24282391

  8. Chemical release and radiation effects (CRRES) data directory

    NASA Astrophysics Data System (ADS)

    Miller, George P.

    1993-04-01

    The following tasks were completed under this contract: a revision and update of the Chemical Release and Radiation Effects (CRRES) data directory was performed taking into account the corrections and suggests for improvements obtained from the participants at the final CRRES IWG meeting held at SAIC on 14-16 Dec. 1992. A draft copy of the report was then circulated to as many as possible of the relevant CRRES Principal Investigators, co-Investigators, and technicians with a request for a final check on accuracy and completion. A copy of the mailing list is given in Appendix A. All corrections and updates received were implemented. A hard copy together with a floppy disk version was forwarded to Richard Howard, NASA Headquarters, who is arranging for the archiving of the CRRES Data Summary at NSSDC. Final copies were sent where possible.

  9. Chemically amplified resist using self-solubility acceleration effect

    NASA Astrophysics Data System (ADS)

    Kihara, Naoko; Ushirogouchi, Tohru; Tada, Tsukasa; Naito, Takuya; Saito, Satoshi; Nakase, Makoto

    1994-11-01

    This paper concerns a novel three-component chemically amplified positive tone resist system for EB lithography composed of a novolak resin, an acid generator, and a newly synthesized dissolution inhibitor. To obtain resist materials with high sensitivity and high contrast, the authors synthesized four 1-(3H)-isobenzofuranone derivatives as novel dissolution inhibitors, which contain a tert-butoxycarbonyl (t-Boc) group and a lactone ring. The t-Boc group of these dissolution inhibitors was effectively decomposed by an acid catalyzed thermal reaction. In addition to this decomposition, the lactone ring of the decomposed product was spontaneously cleft in an aqueous base to generate carboxylic acid. Among these synthesized substances, only the t-Boc derivative of o-cresolphthalein, named CP-TBOC, showed an excellent solubility in 1-acetoxy-2-ethoxyethane. The subsequent cleavage in an aqueous developer was investigated by UV-visible spectroscopy.

  10. Chemical release and radiation effects (CRRES) data directory

    NASA Technical Reports Server (NTRS)

    Miller, George P.

    1993-01-01

    The following tasks were completed under this contract: a revision and update of the Chemical Release and Radiation Effects (CRRES) data directory was performed taking into account the corrections and suggests for improvements obtained from the participants at the final CRRES IWG meeting held at SAIC on 14-16 Dec. 1992. A draft copy of the report was then circulated to as many as possible of the relevant CRRES Principal Investigators, co-Investigators, and technicians with a request for a final check on accuracy and completion. A copy of the mailing list is given in Appendix A. All corrections and updates received were implemented. A hard copy together with a floppy disk version was forwarded to Richard Howard, NASA Headquarters, who is arranging for the archiving of the CRRES Data Summary at NSSDC. Final copies were sent where possible.

  11. Non-cancer effects of chemical agents on children's health.

    PubMed

    Röösli, Martin

    2011-12-01

    This paper provides an overview about the non-cancer health effects for children from relevant chemical agents in our environment. In addition, a meta-analysis was conducted on the association between sudden infant death syndrome (SIDS) and maternal smoking during pregnancy as well as postnatal exposure to environmental tobacco smoke (ETS). In children, birth deformities, neurodevelopment, reproductive outcomes and respiratory system are mainly affected by chemical exposures. According to recent systematic reviews, evidence is sufficient for cognitive impairments caused by low lead exposure levels. Evidence for neurotoxicity from prenatal methylmercury exposure is sufficient for high exposure levels and limited for low levels. Prenatal exposure to polychlorinated biphenyls (PCB) and related toxicants results in cognitive and motor deficits. Maternal smoking during pregnancy is a risk factor for preterm birth, foetal growth deficit and SIDS. The meta-analytic pooled risk estimate for SIDS based on 15 studies is 2.94 (95% confidence interval: 2.43-3.57). Postnatal exposure to ETS was found to increase the SIDS risk by a factor of 1.72 (95% CI: 1.28-2.30) based on six studies which took into account maternal smoking during pregnancy. Additionally, postnatal ETS exposure causes acute respiratory infections, ear problems, respiratory symptoms, more severe asthma, and it slows lung growth. These health effects are also of concern for postnatal exposure to ambient and indoor air pollution. Children differ from adults with respect to several aspects which are relevant for assessing their health risk. Thus, independent evaluation of toxicity in childhood populations is essential. PMID:21906619

  12. Effect of SO/sub 2/ on light modulation of plant metabolism. Progress report

    SciTech Connect

    Anderson, L.E.

    1985-01-01

    This progress report briefly notes conclusions of work done on SO/sub 2/ effect on light modulation of plant metabolism. Conclusions include: effect of light activation on kinetic parameters of fructosebisphosphatase - for this enzyme K/sub m/ decreases and V/sub max/ increases as a result of light activation; and the effect of sulfite and arsenite on light activation in 2 Pisum cultivars - the differences in sensitivity to SO/sub 2/ is directly reflected in differences in a thylakoid bound factor (LEM) to SO/sub 2/.

  13. [Study on Chemical Kinetic Effect of Dielectric Barrier Discharge Plasma].

    PubMed

    Zrang, Peng; Hong, Yan-ji; Shen, Shuang-yan; Ding, Xiao-yu; Ma, Di

    2015-03-01

    To reveal the mechanism of plasma (assisted the ignition process of methane/air further, schematic of dielectric barrier discharge plasma system with atmospheric air was designed and set up, the emission spectrum of dielectric barrier discharge plasma with atmospheric air was measured, and the active particles produced by the interaction of dielectric barrier discharge plasma with atmospheric air were analyzed with the spectrum technology, the ignition model and calculation methods of sensitivity analysis and reaction path analysis were given, effects of NO and O3 on the ignition delay time were simulated, and the chemical kinetics mechanism of NO and O3 assisted ignition was revealed via sensitivity analysis and reaction path analysis. The results show that main excited particles of N2 and O3 are generated via effect of plasma on the atmospheric air, which are converted into active particles of NO(ξ) and O3 in the end, the life of which are longer than any other active particles, effects of plasma on the ignition is simplified as effects of NO(ξ) and O3 on the ignition; NO and O3 could reduce the ignition delay time significantly, but the amplitude decrease with increase of the initial temperature, this is because the rate of ignition is decided by the oxidation rate of CH3, the oxidized pathway of CH3 is R155 and R156 for auto-ignition and their rates are slower when temperature is low, so the ignition delay time of methane/air is longer; NO could reduce the ignition delay time significantly because of the oxidized pathway of CH3 is changed to R327 CH3O2 + NO = CH3O + NO2, R328 CH3 + NO2 = CH3O + NO for NO(ξ) (assisted ignition process from R155 and R156 for auto-ignition; and the chemical kinetic effect is the dominating factor of O3 on the ignition and which change the reaction path. PMID:26117883

  14. Effect of light irradiation on the characteristics of organic field-effect transistors

    SciTech Connect

    Noh, Yong-Young; Ghim, Jieun; Kang, Seok-Ju; Baeg, Kang-Jun; Kim, Dong-Yu; Yase, Kiyoshi

    2006-11-01

    The effect of light irradiation on the characteristics of organic field-effect transistors containing sexithiophene (6-T) and pentacene was examined. Organic phototransistors (OPTs) in which 6-T and pentacene were incorporated were fabricated. Their response behaviors were investigated under conditions of irradiation by either modulated or continuous ultraviolet light with various intensities. Both devices showed two distinguishable responses, i.e., fast and slow responses from photoconductive and photovoltaic effects, respectively. The fast response is mainly the result of the generation of mobile carriers by the absorption of a photon energy higher than the band gap energy of the semiconductor and, subsequently, an increase in conductance via a greater flow of photogenerated mobile carriers into the channel layer. On the other hand, the slow response, which was confirmed by a light induced shift in the threshold voltage (V{sub th}) or the switch-on voltage (V{sub O}), is the result of a slow release of accumulated and trapped electrons in the semiconductor-gate dielectric interface. The V{sub O} is defined as the flatband voltage of devices. Below the V{sub O}, the channel current with the gate voltage is off current, and the channel current increases with the gate voltage above the V{sub O}. The speed of release of the accumulated charge was dependent on the type of semiconductor used. Pentacene OPTs showed a particularly long retention time. Even after storage for ten days, the shifted V{sub O} (or V{sub th}) for the pentacene OPTs by light irradiation was not restored to the original value of the fresh devices. We conclude that this long sustained V{sub th} shift renders them attractive for use in ''light-addressable nonvolatile memory devices.''.

  15. Effect of silicon resistivity on its porosification using metal induced chemical etching: morphology and photoluminescence studies

    NASA Astrophysics Data System (ADS)

    Saxena, Shailendra K.; Sahu, Gayatri; Kumar, Vivek; Sahoo, P. K.; Sagdeo, Pankaj R.; Kumar, Rajesh

    2015-03-01

    The structure and light-emitting properties of porous Si nanowires (Si NWs) fabricated by metal induced chemical etching (MIE) process on two different Si substrates of different resistivities have been investigated here. The surface morphological studies have been carried out using scanning electron microscopy. It is observed that porous Si containing well aligned Si NWs is formed from high resistivity (1-20 Ωcm) Si wafer, whereas interconnected pores or cheese-like structures are formed from low resistivity (0.2 Ωcm) Si wafers after MIE. An explanation for the different porosification processes has been proposed based on the initial doping level, where number of dopants seems to be playing an important role in the etching process. Visible photoluminescence (PL) has been observed from all the porous Si samples, that are attributed due to quantum confinement effect.

  16. Effect of selected spices on chemical and sensory markers in fortified rye-buckwheat cakes.

    PubMed

    Przygodzka, Małgorzata; Zieliński, Henryk; Ciesarová, Zuzana; Kukurová, Kristina; Lamparski, Grzegorz

    2016-07-01

    The aim of this study was to find out the effect of selected spices on chemical and sensorial markers in cakes formulated on rye and light buckwheat flour fortified with spices. Among collection of spices, rye-buckwheat cakes fortified individually with cloves, nutmeg, allspice, cinnamon, vanilla, and spice mix revealed the highest sensory characteristics and overall quality. Cakes fortified with cloves, allspice, and spice mix showed the highest antioxidant capacity, total phenolics, rutin, and almost threefold higher available lysine contents. The reduced furosine content as well as free and total fluorescent intermediatory compounds were observed as compared to nonfortified cakes. The FAST index was significantly lowered in all cakes enriched with spices, especially with cloves, allspice, and mix. In contrast, browning index increased in compare to cakes without spices. It can be suggested that clove, allspice, vanilla, and spice mix should be used for production of safety and good quality cakes. PMID:27386114

  17. Effects of various LED light wavelengths and intensities on microalgae-based simultaneous biogas upgrading and digestate nutrient reduction process.

    PubMed

    Zhao, Yongjun; Wang, Juan; Zhang, Hui; Yan, Cheng; Zhang, Yuejin

    2013-05-01

    Biogas is a well-known, primary renewable energy source, but its utilizations are possible only after upgrading. The microalgae-based bag photo-bioreactor utilized in this research could effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. Red light was determined as the optimal light wavelength for microalgae growth, biogas upgrading, and digestate nutrient reduction. In the range of moderate light intensities (i.e., 800, 1200, 1600, and 2000 μmol m(-2) s(-1)), higher light intensities achieved higher biogas upgrade and larger digestate nutrient reduction. Methane content attained the highest value of 92.74±3.56% (v/v). The highest chemical oxygen demand, total nitrogen, and total phosphorus reduction efficiency of digestate were 85.35±1.04%, 77.98±1.84%, and 73.03±2.14%, respectively. Considering the reduction and economic efficiencies of the carbon dioxide content of biogas and digestate nutrient as well as the biogas upgrading standard, the optimal light intensity range was determined to be from 1200 to 1600 μmol m(-2) s(-1). PMID:23567717

  18. Modeling the effects of chemical exposure on avian seasonal productivity: Importance of differences in breeding strategies

    EPA Science Inventory

    Agencies that regulate the use of chemicals are increasingly interested in understanding the magnitude of effects of those chemicals on wildlife populations. While laboratory toxicity tests provide insights into the types of effects caused by chemical exposure, they do not alway...

  19. The Effects of Hazardous Chemical Exposure on Cardiovascular Disease in Chemical Products Manufacturing Workers

    PubMed Central

    Won, Yong Lim; Ko, Kyung Sun; Heo, Kyung-Hwa; Chung, Yong Hyun

    2012-01-01

    The purpose of this study was to understand the mechanism of cardiovascular disease (CVD) caused by exposure to hazardous chemicals. We investigated changes in the symptoms of metabolic syndrome, which is strongly related to CVD, and in levels of other CVD risk factors, with a special emphasis on the roles of catecholamines and oxidative stress. The results revealed that neither body mass index (BMI) nor waist and hip circumferences were associated with exposure to hazardous chemicals. Among metabolic syndrome criteria, only HDL-cholesterol level increased on exposure to hazardous chemicals. Levels of epinephrine (EP) and norepinephrine (NEP) were not influenced by exposure to hazardous chemicals; however, the total antioxidative capacity (TAC) reduced because of increased oxidative stress. Both hazardous chemical exposure level and metabolite excretion were related to EP, NEP, and the oxidative stress index (OSI). Logistic regression analysis with these factors as independent variables and metabolic syndrome criteria as dependent variables revealed that EP was associated with blood pressure, and NEP with metabolic syndrome in the chemicalexposed group. In conclusion, the results suggest that reactive oxygen species generated and oxidative stress due to exposure to hazardous chemicals act as mediators and cause changes in the physiological levels of EP and NEP to increase blood pressure. This ultimately leads to the development of CVD through increase in cholesterol, triglyceride, and blood glucose levels by lipid peroxidation. PMID:24278620

  20. The effects of hazardous chemical exposure on cardiovascular disease in chemical products manufacturing workers.

    PubMed

    Kim, Ki-Woong; Won, Yong Lim; Ko, Kyung Sun; Heo, Kyung-Hwa; Chung, Yong Hyun

    2012-12-01

    The purpose of this study was to understand the mechanism of cardiovascular disease (CVD) caused by exposure to hazardous chemicals. We investigated changes in the symptoms of metabolic syndrome, which is strongly related to CVD, and in levels of other CVD risk factors, with a special emphasis on the roles of catecholamines and oxidative stress. The results revealed that neither body mass index (BMI) nor waist and hip circumferences were associated with exposure to hazardous chemicals. Among metabolic syndrome criteria, only HDL-cholesterol level increased on exposure to hazardous chemicals. Levels of epinephrine (EP) and norepinephrine (NEP) were not influenced by exposure to hazardous chemicals; however, the total antioxidative capacity (TAC) reduced because of increased oxidative stress. Both hazardous chemical exposure level and metabolite excretion were related to EP, NEP, and the oxidative stress index (OSI). Logistic regression analysis with these factors as independent variables and metabolic syndrome criteria as dependent variables revealed that EP was associated with blood pressure, and NEP with metabolic syndrome in the chemicalexposed group. In conclusion, the results suggest that reactive oxygen species generated and oxidative stress due to exposure to hazardous chemicals act as mediators and cause changes in the physiological levels of EP and NEP to increase blood pressure. This ultimately leads to the development of CVD through increase in cholesterol, triglyceride, and blood glucose levels by lipid peroxidation. PMID:24278620

  1. Graphene oxide/α-Bi(2)O(3) composites for visible-light photocatalysis, chemical catalysis, and solar energy conversion.

    PubMed

    Som, Tirtha; Troppenz, Gerald V; Wendt, R Robert; Wollgarten, Markus; Rappich, Jörg; Emmerling, Franziska; Rademann, Klaus

    2014-03-01

    The growing challenges of environmental purification by solar photocatalysis, precious-metal-free catalysis, and photocurrent generation in photovoltaic cells receive the utmost global attention. Here we demonstrate a one-pot, green chemical synthesis of a new stable heterostructured, ecofriendly, multifunctional microcomposite that consists of α-Bi2 O3 microneedles intercalated with anchored graphene oxide (GO) microsheets (1.0 wt %) for the above-mentioned applications on a large economical scale. The bare α-Bi2 O3 microneedles display two times better photocatalytic activities than commercial TiO2 (Degussa-P25), whereas the GO-hybridized composite exhibits approximately four to six times enhanced photocatalytic activities than the neat TiO2 photocatalyst in the degradation of colored aromatic organic dyes (crystal violet and rhodamine 6G) under visible-light irradiation (300 W tungsten lamp). The highly efficient activity is associated with the strong surface adsorption ability of GO for aromatic dye molecules, the high carrier acceptability, and the efficient electron-hole pair separation in Bi2 O3 by individual adjoining GO sheets. The introduction of Ag nanoparticles (2.0 wt %) further enhances the photocatalytic performance of the composite over eightfold because of a plasmon-induced electron-transfer process from Ag nanoparticles through the GO sheets into the conduction band of Bi2 O3 . The new composites are also catalytically active and catalyze the reduction of 4-nitrophenol to 4-aminophenol in the presence of borohydride ions. Photoanodes assembled from GO/α-Bi2 O3 and Ag/GO/α-Bi2 O3 composites display an improved photocurrent response (power conversion efficiency ∼20 % higher) over those prepared without GO in dye-sensitized solar cells. PMID:24578169

  2. Incorporation of a Doubly Functionalized Synthetic Amino Acid into Proteins for Creating Chemical and Light-Induced Conjugates.

    PubMed

    Yamaguchi, Atsushi; Matsuda, Takayoshi; Ohtake, Kazumasa; Yanagisawa, Tatsuo; Yokoyama, Shigeyuki; Fujiwara, Yoshihisa; Watanabe, Takayoshi; Hohsaka, Takahiro; Sakamoto, Kensaku

    2016-01-20

    Z-Lysine (ZLys) is a lysine derivative with a benzyloxycarbonyl group linked to the ε-nitrogen. It has been genetically encoded with the UAG stop codon, using the pair of an engineered variant of pyrrolysyl-tRNA synthetase (PylRS) and tRNA(Pyl). In the present study, we designed a novel Z-lysine derivative (AmAzZLys), which is doubly functionalized with amino and azido substituents at the meta positions of the benzyl moiety, and demonstrated its applicability for creating protein conjugates. AmAzZLys was incorporated into proteins in Escherichia coli, by using the ZLys-specific PylRS variant. AmAzZLys was then site-specifically incorporated into a camelid single-domain antibody specific to the epidermal growth factor receptor (EGFR). A one-pot reaction demonstrated that the phenyl amine and azide were efficiently linked to the 5 kDa polyethylene glycol and a fluorescent probe, respectively, through specific bio-orthogonal chemistry. The antibody was then tested for the ability to form a photo-cross-link between its phenylazide moiety and the antigen, while the amino group on the same ring was used for chemical labeling. When incorporated at a selected position in the antibody and exposed to 365 nm light, AmAzZLys formed a covalent bond with the EGFR ectodomain, with the phenylamine moiety labeled fluorescently prior to the reaction. The present results illuminated the versatility of the ZLys scaffold, which can accommodate multiple reactive groups useful for protein conjugation. PMID:26625213

  3. Physiological effects of light on the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Shanahan, T. L.; Czeisler, C. A.

    2000-01-01

    The physiology of the human circadian pacemaker and its influence and on the daily organization of sleep, endocrine and behavioral processes is an emerging interest in science and medicine. Understanding the development, organization and fundamental properties underlying the circadian timing system may provide insight for the application of circadian principles to the practice of clinical medicine, both diagnostically (interpretation of certain clinical tests are dependent on time of day) and therapeutically (certain pharmacological responses vary with the time of day). The light-dark cycle is the most powerful external influence acting upon the human circadian pacemaker. It has been shown that timed exposure to light can both synchronize and reset the phase of the circadian pacemaker in a predictable manner. The emergence of detectable circadian rhythmicity in the neonatal period is under investigation (as described elsewhere in this issue). Therefore, the pattern of light exposure provided in the neonatal intensive care setting has implications. One recent study identified differences in both amount of sleep time and weight gain in infants maintained in a neonatal intensive care environment that controlled the light-dark cycle. Unfortunately, neither circadian phase nor the time of day has been considered in most clinical investigations. Further studies with knowledge of principles characterizing the human circadian timing system, which governs a wide array of physiological processes, are required to integrate these findings with the practice of clinical medicine.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The activity of blue light (470nm) alone on (1) bacterial viability, and (2) with a food grade photosensitizer on filamentous fungal viability, was studied. Suspensions of the bacteria Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA), and Pseudomonas aeruginosa (PA) were prepared and aliquo...

  5. New effective chemically synthesized anti-smallpox compound NIOCH-14.

    PubMed

    Mazurkov, Oleg Yu; Kabanov, Alexey S; Shishkina, Larisa N; Sergeev, Alexander A; Skarnovich, Maksim O; Bormotov, Nikolay I; Skarnovich, Maria A; Ovchinnikova, Alena S; Titova, Ksenya A; Galahova, Darya O; Bulychev, Leonid E; Sergeev, Artemiy A; Taranov, Oleg S; Selivanov, Boris A; Tikhonov, Alexey Ya; Zavjalov, Evgenii L; Agafonov, Alexander P; Sergeev, Alexander N

    2016-05-01

    Antiviral activity of the new chemically synthesized compound NIOCH-14 (a derivative of tricyclodicarboxylic acid) in comparison with ST-246 (the condensed derivative of pyrroledione) was observed in experiments in vitro and in vivo using orthopoxviruses including highly pathogenic ones. After oral administration of NIOCH-14 to outbred ICR mice infected intranasally with 100 % lethal dose of ectromelia virus, it was shown that 50 % effective doses of NIOCH-14 and ST-246 did not significantly differ. The 'therapeutic window' varied from 1 day before infection to 6 days post-infection (p.i.) to achieve 100-60 % survival rate. The administration of NIOCH-14 and ST-246 to mice resulted in a significant reduction of ectromelia virus titres in organs examined as compared with the control and also reduced pathological changes in the lungs 6 days p.i. Oral administration of NIOCH-14 and ST-246 to ICR mice and marmots challenged with monkeypox virus as compared with the control resulted in a significant reduction of virus production in the lungs and the proportion of infected mice 7 days p.i. as well as the absence of disease in marmots. Significantly lower proportions of infected mice and virus production levels in the lungs as compared with the control were demonstrated in experiments after oral administration of NIOCH-14 and ST-246 to ICR mice and immunodeficient SCID mice challenged with variola virus 3 and 4 days p.i., respectively. The results obtained suggest good prospects for further study of the chemical compound NIOCH-14 to create a new smallpox drug on its basis. PMID:26861777

  6. Effects of incomplete mixing on chemical reactions under flow heterogeneities.

    NASA Astrophysics Data System (ADS)

    Perez, Lazaro; Hidalgo, Juan J.; Dentz, Marco

    2016-04-01

    Evaluation of the mixing process in aquifers is of primary importance when assessing attenuation of pollutants. In aquifers different hydraulic and chemical properties can increase mixing and spreading of the transported species. Mixing processes control biogeochemical transformations such as precipitation/dissolution reactions or degradation reactions that are fast compared to mass transfer processes. Reactions are local phenomena that fluctuate at the pore scale, but predictions are often made at much larger scales. However, aquifer heterogeities are found at all scales and generates flow heterogeneities which creates complex concentration distributions that enhances mixing. In order to assess the impact of spatial flow heterogeneities at pore scale we study concentration profiles, gradients and reaction rates using a random walk particle tracking (RWPT) method and kernel density estimators to reconstruct concentrations and gradients in two setups. First, we focus on a irreversible bimolecular reaction A+B → C under homogeneous flow to distinguish phenomena of incomplete mixing of reactants from finite-size sampling effects. Second, we analise a fast reversible bimolecular chemical reaction A+B rightleftharpoons C in a laminar Poiseuille flow reactor to determine the difference between local and global reaction rates caused by the incomplete mixing under flow heterogeneities. Simulation results for the first setup differ from the analytical solution of the continuum scale advection-dispersion-reaction equation studied by Gramling et al. (2002), which results in an overstimation quantity of reaction product (C). In the second setup, results show that actual reaction rates are bigger than the obtained from artificially mixing the system by averaging the concentration vertically. - LITERATURE Gramling, C. M.,Harvey, C. F., Meigs, and L. C., (2002). Reactive transport in porous media: A comparison of model prediction with laboratory visualization, Environ. Sci

  7. The effect of chemical additives on the synthesis of ethanol

    SciTech Connect

    Chuang, S.S.C.

    1989-04-30

    The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativeities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimental studies of NO adsorption, reactive probing, steady state rate measurement, and transient kinetic study. CO insertion is known to be a key step to the formation of acetaldehyde and ethanol from CO hydrogenation. Reaction of ethylene with syngas is used as a probe to determine CO insertion capabilities of metal catalysts. During the sixth quarter of the project, the mechanism of CO insertion on Ni/SiO{sub 2} was investigated by in-situ infrared spectroscopy. Ni/SiO{sub 2}, a methanation catalyst, has been shown to exhibit CO insertion activity. In situ infrared studies of CO/H{sub 2} and C{sub 2}H{sub 4}/CO/H{sub 2} reactions show that the carbonylation of Ni/SiO{sub 2} to Ni(CO){sub 4} leads to an inhibition of methanation in CO hydrogenation but an enhancement of formation of propionaldehyde in C{sub 2}H{sub 4}/CO/H{sub 2} reaction. The results suggest that the sites for propionaldehyde formation is different from those for methanation.

  8. Light and Gravity Effects on Circadian Rhythms of Rhesus Macaques

    NASA Technical Reports Server (NTRS)

    Fuller, Charles

    1997-01-01

    Temporal integration of a biological organism's physiological, behavioral and biochemical systems depends upon its circadian timing system. The endogenous period of this timing system is typically synchronized to the 24- hour day by environmental cues. The daily alternation of light and dark has long been known as one of the most potent environmental synchronizers influencing the circadian timing system. Alterations in the lighting environment (length or intensity of light exposure) can also affect the homeostatic state of the organism. A series of experiments was performed using rhesus monkeys with the objective of defining the fundamental properties of the circadian rhythm of body temperature. Three major experiments were performed in addition to several preliminary studies. These experiments explored 1.) the response of the rhesus body temperature rhythm to varying day length and light intensity; 2.) the response of the body temperature rhythm to light exposure as a function of time of day; and 3.) the characteristics of the metabolic heat production rhythm which is responsible for the daily cycle in body temperature. Results of these three completed experiments will be reported here. In addition, preliminary experiments were also performed in social entrainment of rhesus circadian rhythms and the properties of rhesus body temperature rhythms in constant conditions, where no external time cues were provided. Four adult male rhesus monkeys served as subjects in all experiments. All experiments were performed at the California Regional Primate Research Center. Each animal was implanted with a biotelemetry unit that measured deep body temperature. All surgeries were performed by a board certified veterinary surgeon under sterile conditions. The biotelemetry implants also provided an index of activity level in each animal. For metabolic heat production measurements, oxygen consumption and carbon dioxide production were measured and the caloric equivalent of these

  9. Effects of spectral parameters on the light properties of red-green-blue white light-emitting diodes.

    PubMed

    Xu, Mingsheng; Zhang, Haoxiang; Zhou, Quanbin; Wang, Hong

    2016-06-01

    Red-green-blue white light-emitting diodes (RGB-WLEDs) have great potential as commercial solid-state lighting devices, as well as visible light communication because of their high color-rendering index (CRI) and high response frequency. The quality of light of an RGB-WLED strongly depends on its spectral parameters. In this study, we fabricated RGB-WLEDs with red, blue, and green LEDs and measured the spectral power distribution (SPD). The experimental SPD is consistent with the calculated spectrum. We also measured the SPDs of LEDs with different peak wavelengths and extracted the spectral parameters, which were then used for modeling. We studied the effect of the wavelength and the full width at half-maximum (FWHM) on both the color rendering index and the luminous efficiency (LE) of the RGB-WLED using simulations. We find that the LE improves as the wavelength of the blue LED increases and the wavelength of the red LED decreases. When the wavelength of the green LED increases, the LE increases first, but later decreases. The CRI of the RGB-WLED increases with the wavelengths of the red, blue, and green LEDs first, but then decreases. The optimal wavelengths and FWHMs for maximum color-rendering and LE of the blue, green, and red LEDs are 466, 536, 606 nm; and 26.0, 34.0, and 19.5 nm, respectively. PMID:27411203

  10. Coriolis effect and spin Hall effect of light in an inhomogeneous chiral medium.

    PubMed

    Zhang, Yongliang; Shi, Lina; Xie, Changqing

    2016-07-01

    We theoretically investigate the spin Hall effect of spinning light in an inhomogeneous chiral medium. The Hamiltonian equations of the photon are analytically obtained within eikonal approximation in the noninertial orthogonal frame. Besides the usual spin curvature coupling, the chiral parameter enters the Hamiltonian as a spin-torsion-like interaction. We reveal that both terms have parallel geometric origins as the Coriolis terms of Maxwell's equations in nontrivial frames. PMID:27367104

  11. A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans

    PubMed Central

    Beaven, C. Martyn; Ekström, Johan

    2013-01-01

    The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention. PMID:24282477

  12. Chemicals and lemon essential oil effect on Alicyclobacillus acidoterrestris viability.

    PubMed

    Maldonado, Maria Cristina; Aban, Marina Paola; Navarro, Antonio Roberto

    2013-12-01

    Alicyclobacillus acidoterrestris is considered to be one of the important target microorganisms in the quality control of acidic canned foods. There is an urgent need to develop a suitable method for inhibiting or controlling the germination and outgrowth of A.acidoterrestris in acidic drinks. The aim of this work was to evaluate the chemicals used in the lemon industry (sodium benzoate, potassium sorbate), and lemon essential oil as a natural compound, against a strain of A.acidoterrestris in MEB medium and in lemon juice concentrate. The results pointed out that sodium benzoate (500-1000-2000 ppm) and lemon essential oil (0.08-0.12-0.16%) completely inhibited the germination of A. acidoterrestris spores in MEB medium and LJC for 11 days. Potassium sorbate (600-1200 ppm) was more effective to inhibit the growth of the microbial target in lemon juice than in MEB medium. The effect of sodium benzoate, potassium sorbate and essential oil was sporostatic in MEB and LJC as they did not affect spore viability. PMID:24688502

  13. Effect of flares on the chemical composition of exoplanets atmospheres

    NASA Astrophysics Data System (ADS)

    Venot, O.; Decin, L.

    2015-10-01

    M stars are very abundant in our Galaxy, and very likely harbour the majority of planetary systems. But a particularity of M stars is that they are the most active class of stars. Indeed, they experience stellar variability such as flares. These violent and unpredictable outbursts originate from the photosphere and are caused by magnetic processus. During such an event, the energy emitted by the star can vary by several orders of magnitude for the whole wavelength range. It results in an enhancement of the H# emission and of the continuum. Different studies on the effect of flares on exoplanets have already been conducted [1, 2]. Here we are interested in the effect of a flare on the atmospheric composition of a warm Neptune orbiting around an M star. Using the stellar flux of AD Leo recorded during a flare event [1] and the chemical model of [3], we have studied the impact on the atmosphere. We have also computed the synthetic spectra assuming that such an event occurs during a transit. We will present these results.

  14. Chemicals and lemon essential oil effect on Alicyclobacillus acidoterrestris viability

    PubMed Central

    Maldonado, Maria Cristina; Aban, Marina Paola; Navarro, Antonio Roberto

    2013-01-01

    Alicyclobacillus acidoterrestris is considered to be one of the important target microorganisms in the quality control of acidic canned foods. There is an urgent need to develop a suitable method for inhibiting or controlling the germination and outgrowth of A.acidoterrestris in acidic drinks. The aim of this work was to evaluate the chemicals used in the lemon industry (sodium benzoate, potassium sorbate), and lemon essential oil as a natural compound, against a strain of A.acidoterrestris in MEB medium and in lemon juice concentrate. The results pointed out that sodium benzoate (500–1000–2000 ppm) and lemon essential oil (0.08–0.12–0.16%) completely inhibited the germination of A. acidoterrestris spores in MEB medium and LJC for 11 days. Potassium sorbate (600–1200 ppm) was more effective to inhibit the growth of the microbial target in lemon juice than in MEB medium. The effect of sodium benzoate, potassium sorbate and essential oil was sporostatic in MEB and LJC as they did not affect spore viability. PMID:24688502

  15. Comparative effectiveness of light emitting diodes (LEDs) and Lasers in near infrared photoimmunotherapy.

    PubMed

    Sato, Kazuhide; Watanabe, Rira; Hanaoka, Hirofumi; Nakajima, Takahito; Choyke, Peter L; Kobayashi, Hisataka

    2016-03-22

    Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two NIR-light sources; light emitting diodes (LEDs) and Lasers, for their effectiveness in NIR-PIT. A photosensitizer, IRDye-700DX, conjugated to panitumumab (pan-IR700), was incubated with EGFR-expressing A431 and MDA-MB-468-luc cells. NIR-light was provided by LEDs or Lasers at the same light dose. Laser-light produced more cytotoxicity and greater reductions in IR700-fluorescence intensity than LED-light. Laser-light also produced more cytotoxicity in vivo in both cell lines. Assessment of super-enhanced permeability and retention (SUPR) effects were stronger with Laser than LED. These results suggest that Laser-light produced significantly more cytotoxic effects compared to LEDs. Although LED is less expensive, Laser-light produces superior results in NIR-PIT. PMID:26885688

  16. Comparative effectiveness of light emitting diodes (LEDs) and Lasers in near infrared photoimmunotherapy

    PubMed Central

    Sato, Kazuhide; Watanabe, Rira; Hanaoka, Hirofumi; Nakajima, Takahito; Choyke, Peter L.; Kobayashi, Hisataka

    2016-01-01

    Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photosensitizers after exposure to near infrared (NIR) light. Herein we compare two NIR-light sources; light emitting diodes (LEDs) and Lasers, for their effectiveness in NIR-PIT. A photosensitizer, IRDye-700DX, conjugated to panitumumab (pan-IR700), was incubated with EGFR-expressing A431 and MDA-MB-468-luc cells. NIR-light was provided by LEDs or Lasers at the same light dose. Laser-light produced more cytotoxicity and greater reductions in IR700-fluorescence intensity than LED-light. Laser-light also produced more cytotoxicity in vivo in both cell lines. Assessment of super-enhanced permeability and retention (SUPR) effects were stronger with Laser than LED. These results suggest that Laser-light produced significantly more cytotoxic effects compared to LEDs. Although LED is less expensive, Laser-light produces superior results in NIR-PIT. PMID:26885688

  17. Effects of ultraviolet light on the eye: Role of protective glasses

    SciTech Connect

    Kuijk, F.J.G.M. van )

    1991-12-01

    Global atmospheric changes such as depletion of ozone in the stratosphere are though to lead to increased levels of ultraviolet radiation on earth. This can have adverse effects on human health, and long-term effects of ultraviolet light on the eye are of increasing concern. Ultraviolet light exposure to the eye has been associated with cataract formation and retinal degeneration. In both cases, it is hypothesized that ultraviolet light can initiate formation of free radicals, which can cause protein modification and lipid peroxidation. Several procedures can be recommended to prevent ultraviolet light damage to the eye, such as the use of suitable protective glasses when outdoors. 101 refs., 2 figs. 1 tab.

  18. Exhaust emissions from light- and heavy-duty vehicles: chemical composition, impact of exhaust after treatment, and fuel parameters.

    PubMed Central

    Westerholm, R; Egebäck, K E

    1994-01-01

    This paper presents results from the characterization of vehicle exhaust that were obtained primarily within the Swedish Urban Air Project, "Tätortsprojektet." Exhaust emissions from both gasoline- and diesel-fueled vehicles have been investigated with respect to regulated pollutants (carbon monoxide [CO], hydrocarbon [HC], nitrogen oxides [NOx], and particulate), unregulated pollutants, and in bioassay tests (Ames test, TCDD receptor affinity tests). Unregulated pollutants present in both the particle- and the semi-volatile phases were characterized. Special interest was focused on the impact of fuel composition on heavy-duty diesel vehicle emissions. It was confirmed that there exists a quantifiable relationship between diesel-fuel variables of the fuel blends, the chemical composition of the emissions, and their biological effects. According to the results from the multivariate analysis, the most important fuel parameters are: polycyclic aromatic hydrocarbons (PAH) content, 90% distillation point, final boiling point, specific heat, aromatic content, density, and sulfur content. PMID:7529699

  19. [Effects of maize-peanut intercropping on economic yield and light response of photosynthesis].

    PubMed

    Jiao, Nian-Yuan; Zhao, Chun; Ning, Tang-Yuan; Hou, Lian-Tao; Fu, Guo-Zhan; Li, Zeng-Jia; Chen, Ming-Can

    2008-05-01

    A field experiment was conducted to study the effects of maize-peanut intercropping on the economic yield of the two crops and the light response of their functional leaves' photosynthesis. The results showed that maize-peanut intercropping had an obvious yield advantage, with the total economic yield being 2,896 kg hm(-2) in 2004 and 2,894 kg hm(-2) in 2005, and enhanced the land utilization rate by 14%-17%. For maize's functional leaves, the intercropping enhanced their light saturation point, compensation point, and photosynthetic rate under strong light; while for peanut's functional leaves, it reduced their light saturation point and compensation point but enhanced the apparent quantum yield of photosynthesis and photosynthetic rate under weak light, indicating that maize-peanut intercropping enhanced the utilization efficiency of strong light by maize and that of weak light by peanut, making this intercropping system present an obvious yield advantage. PMID:18655581

  20. Effect of blue light radiation on curcumin-induced cell death of breast cancer cells

    NASA Astrophysics Data System (ADS)

    Zeng, X. B.; Leung, A. W. N.; Xia, X. S.; Yu, H. P.; Bai, D. Q.; Xiang, J. Y.; Jiang, Y.; Xu, C. S.

    2010-06-01

    In the present study, we have successfully set up a novel blue light source with the power density of 9 mW/cm2 and the wavelength of 435.8 nm and then the novel light source was used to investigate the effect of light radiation on curcumin-induced cell death. The cytotoxicity was investigated 24 h after the treatment of curcumin and blue light radiation together using MTT reduction assay. Nuclear chromatin was observed using a fluorescent microscopy with Hoechst33258 staining. The results showed blue light radiation could significantly enhance the cytotoxicity of curcumin on the MCF-7 cells and apoptosis induction. These findings demonstrated that blue light radiation could enhance curcumin-induced cell death of breast cancer cells, suggesting light radiation may be an efficient enhancer of curcumin in the management of breast cancer.

  1. Effects of relative humidity on aerosol light scattering: results from different European sites

    NASA Astrophysics Data System (ADS)

    Zieger, P.; Fierz-Schmidhauser, R.; Weingartner, E.; Baltensperger, U.

    2013-04-01

    The effect of aerosol water uptake on the aerosol particle light scattering coefficient (σsp) is described in this study by comparing measurements from five European sites: the Jungfraujoch, located in the Swiss Alps at 3580 m a.s.l., Ny-Ålesund, located on Spitsbergen in the Arctic, Mace Head, a coastal site in Ireland, Cabauw, a rural site in the Netherlands and Melpitz, a regional background site in Eastern Germany. These sites were selected according to the aerosol type usually encountered at that location. The scattering enhancement factor f(RH,λ) is the key parameter to describe the effect of water uptake on the particle light scattering. It is defined as the σsp(RH) at a certain relative humidity (RH) and wavelength λ divided by its dry value. f(RH) largely varied at the five sites starting from very low values of f(RH = 85%,λ = 550 nm) around 1.28 for mineral dust to 3.41 for Arctic aerosol. Hysteresis behavior was observed at all sites except at the Jungfraujoch due to the absence of sea salt. Closure studies and Mie simulations showed that both size and chemical composition determine the magnitude of f(RH). Both parameters are also needed to successfully predict f(RH). Finally, the measurement results were compared to the widely used aerosol model OPAC (Hess et al., 1998). Significant discrepancies were seen especially at intermediate RH ranges, which were mainly attributed to inappropriate implemented hygroscopic growth within OPAC. Replacement of the hygroscopic growth with recent literature values showed a clear improvement of the OPAC model.

  2. Effects of relative humidity on aerosol light scattering: results from different European sites

    NASA Astrophysics Data System (ADS)

    Zieger, P.; Fierz-Schmidhauser, R.; Weingartner, E.; Baltensperger, U.

    2013-11-01

    The effect of aerosol water uptake on the aerosol particle light scattering coefficient (σsp) is described in this study by comparing measurements from five European sites: the Jungfraujoch, located in the Swiss Alps at 3580 m a.s.l.; Ny-Ålesund, located on Spitsbergen in the Arctic; Mace Head, a coastal site in Ireland; Cabauw, a rural site in the Netherlands; and Melpitz, a regional background site in Eastern Germany. These sites were selected according to the aerosol type usually encountered at that location. The scattering enhancement factor f(RH, λ) is the key parameter to describe the effect of water uptake on the particle light scattering. It is defined as the σsp(RH) at a certain relative humidity (RH) and wavelength λ divided by its dry value. f(RH) at the five sites varied widely, starting at very low values of f(RH = 85%, λ = 550 nm) around 1.28 for mineral dust, and reaching up to 3.41 for Arctic aerosol. Hysteresis behavior was observed at all sites except at the Jungfraujoch (due to the absence of sea salt). Closure studies and Mie simulations showed that both size and chemical composition determine the magnitude of f(RH). Both parameters are also needed to successfully predict f(RH). Finally, the measurement results were compared to the widely used aerosol model, OPAC (Hess et al., 1998). Significant discrepancies were seen, especially at intermediate RH ranges; these were mainly attributed to inappropriate implementation of hygroscopic growth in the OPAC model. Replacement of the hygroscopic growth with values from the recent literature resulted in a clear improvement of the OPAC model.

  3. Effect of light quality and light-dark cycle on sporulation patterns of the mite pathogenic fungus Neozygites floridana (Neozygitales: Entomophthoromycota), a natural enemy of Tetranychus urticae.

    PubMed

    Klingen, Ingeborg; Holthe, Maren Pindsle; Westrum, Karin; Suthaparan, Aruppillai; Torp, Torfinn

    2016-06-01

    A controlled climatic chamber microcosm experiment was conducted to examine how light affects the hourly sporulation pattern of the beneficial mite pathogenic fungus Neozygites floridana during a 24h cyclus over a period of eight consecutive days. This was done by inoculating two-spotted spider mites (Tetranychus urticae) with N. floridana and placing them on strawberry plants for death and sporulation. Spore (primary conidia) discharge was observed by using a spore trap. Two light regimes were tested: Plant growth light of 150μmolm(-2)s(-1) for 12h supplied by high pressure sodium lamps (HPS), followed by either; (i) 4h of 50μmolm(-2)s(-1) light with similar HPS lamps followed by 8h darkness (full HPS light+reduced HPS light+darkness) or (ii) 4h of 50μmolm(-2)s(-1) red light followed by 8h darkness (full HPS light+red light+darkness). A clear difference in hourly primary conidia discharge pattern between the two different light treatments was seen and a significant interaction effect between light treatment and hour in day during the 24h cycle was observed. The primary conidia discharge peak for treatment (ii) that included red light was mainly reached within the red light hours (19:00-23:00) and the dark hours (23:00-07:00). The primary conidia discharge peak for treatment (i) with HPS light only was mainly reached within the dark hours (23:00-07:00). PMID:27142576

  4. Deducing effective light transport parameters in optically thin systems

    NASA Astrophysics Data System (ADS)

    Mazzamuto, G.; Pattelli, L.; Toninelli, C.; Wiersma, D. S.

    2016-02-01

    We present an extensive Monte Carlo study on light transport in optically thin slabs, addressing both axial and transverse propagation. We systematically characterize diffusive transport in this intermediate scattering regime, notably in terms of the spatial variance of the transmitted/reflected profile. Focusing on late, multiply scattered light, we test the validity of the prediction cast by diffusion theory that the spatial variance should grow independently of absorption and, to a first approximation, of the sample thickness and refractive index contrast. Based on a large set of simulated data, we build a freely available look-up table routine enabling reliable and precise determination of the microscopic transport parameters starting from robust observables which are independent from absolute intensity measurements. We also present the Monte Carlo software package that was developed for the purpose of this study.

  5. Effect of light intensity on broiler production, processing characteristics, and welfare.

    PubMed

    Deep, A; Schwean-Lardner, K; Crowe, T G; Fancher, B I; Classen, H L

    2010-11-01

    Manipulation of light intensity is an important management tool affecting broiler production and well being. Despite considerable research on light intensity, there is still a debate on the optimum level to be used for intensively housed broilers. Two trials were conducted with the objective of investigating the effect of light intensity, within the practical levels at confinement barns (1, 10, 20, and 40 lx), on production, processing characteristics, and welfare of broilers raised to 35 d of age. Each light intensity treatment was replicated in 2 environmentally controlled rooms in each trial with 950 Ross × Ross 308 chicks per room. Data were analyzed as a randomized complete block design with trial serving as a block. All chicks were exposed to 40 lx of light intensity and 23 h of light for the first 7 d followed by treatment light intensity and 17 h of day length thereafter. Body weight and feed consumption were determined at 7, 14, and 35 d of age. At the end of each trial, 60 birds per treatment were processed to determine the detailed meat yield. Skeletal and footpad and ocular health were monitored at 31 and 32 d of age, respectively. Body weight, feed consumption, feed:gain ratio, and mortality were unaffected by light intensity. Carcass, thigh, and drum yield as a percentage of live weight decreased linearly with increasing light intensity. The 1 lx treatment resulted in heavier wings as a percentage of live weight. Light intensity had no effect on skeletal health, but ulcerative footpad lesions decreased linearly with increasing light intensity. Birds exposed to the 1 lx treatment had heavier and larger eyes. In conclusion, light intensity did not affect broiler production and mortality but did affect carcass characteristics. The 1 lx light intensity treatment had a negative effect on broiler welfare as demonstrated by increased ulcerative footpad lesions and eye size. PMID:20952694

  6. Effect of different colored background lighting on LED discomfort glare perception

    NASA Astrophysics Data System (ADS)

    Sweater Hickcox, K.; Narendran, N.; Bullough, J. D.; Freyssinier, J. P.

    2012-10-01

    In the past decade, there has been increased interest in energy-efficient lighting as energy resources become higher in demand. Street lighting and outdoor lighting are applications that are rapidly changing from the incumbent high-pressure sodium (HPS) to newer technologies such as light-emitting diode (LED) or induction-type lamps. There is evidence that certain populations believe LED streetlights and area lights to produce more glare than HPS luminaires. A number of differences exist between new and traditional light sources besides efficiency. These include spectral power distribution (SPD), source luminance, beam intensity distribution, and the number of sources needed to achieve intended light levels. Many field studies and laboratory studies have shown a relationship between glare and SPD, with most studies suggesting that sources more weighted in short wavelengths have an increased likelihood of discomfort glare. A study to assess the effect of different SPDs on perception of discomfort glare was conducted. Subjects were shown a white-light LED array against a luminous background with one of three different SPDs (blue, white, or yellow). As well, different intensities of light from the array and from the background were used. For the range of conditions evaluated, the presence of any luminous background significantly reduced the perception of discomfort glare from the LED array. The blue background reduced perception significantly less than the white or the yellow backgrounds. The implications for solid-state lighting systems such as outdoor array lighting are discussed.

  7. Is it effective to harvest visible light by decreasing the band gap of photocatalytic materials?

    NASA Astrophysics Data System (ADS)

    Fu, Ning; Tang, Xinhu; Li, Dongyang

    2012-02-01

    In situ variations in the electron work function and photo-current of TiO2 nanotubes demonstrate that long-wavelength illumination only has a minor effect on the excitation of electrons in the nanotubes after being exposed to short-wavelength light or when the short-wavelength light coexisted, indicating that the solar spectrum may not be utilized as efficiently as expected by extending the absorption spectrum of the photocatalytic material to visible light range with decreased band gaps.

  8. Improvement of the chemical content prediction of a model powder system by reducing multiple scattering using polarized light spectroscopy.

    PubMed

    Bendoula, Ryad; Gobrecht, Alexia; Moulin, Benoit; Roger, Jean-Michel; Bellon-Maurel, Veronique

    2015-01-01

    Near-infrared spectroscopy (NIRS) is a powerful non-destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in line in industries, in vivo with biomedical applications, or in field for agricultural and environmental applications. However, highly scattering samples subvert Beer-Lambert law's linear relationship between spectral absorbance and the concentration. Instead of spectral pre-processing, which is commonly used by NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, i.e., coupling polarized light with NIR spectrometry, to free spectra from scattering effect. This should allow us to retrieve linear and steady conditions for spectral analysis. When tested in visible-NIR (Vis-NIR) range (400-800 nm) on model media, mixtures of scattering and absorbing particles, the setup provided significant improvements in absorber concentration estimation precision as well as in the quality and robustness of the calibration model. PMID:25498765

  9. A rule-based expert system for chemical prioritization using effects-based chemical categories

    EPA Science Inventory

    A rule-based expert system (ES) was developed to predict chemical binding to the estrogen receptor (ER) patterned on the research approaches championed by Gilman Veith to whom this article and journal issue are dedicated. The ERES was built to be mechanistically-transparent and m...

  10. Effects of irrigation with treated wastewater on chemical soil properties

    NASA Astrophysics Data System (ADS)

    Parvan, M.; Danesh, S.; Alizadeh, A.

    2009-04-01

    The use of treated wastewater, as a marginal quality water, in agriculture is a justified practice, yet care should be taken to minimize adverse environmental impacts and to prevent soil deterioration. The objective of this research was to investigate the long-term effects of irrigation with treated wastewater on soil properties. The investigation was carried out by comparison of soil properties in two different fields; one irrigated with the effluent from Parkand Abad Wastewater Treatment Plant over a period of six years and the other one irrigated with water over the same period of time. Soil samples were taken from different depths of 0-25, 25-50, 50-100, 100-150 and 150-200 cm in both fields, and analyzed for various chemical properties. The results indicated that EC, TDS and Chlorine were increased significantly, in all depths, in the soil irrigated with the treated wastewater. The use of treated wastewater increased exchangeable potassium, magnesium and phosphorous significantly in the top soil layer (0-25), while the increase in calcium was occurred up to depth of 50 cm. Irrigation with the treated wastewater increased soil sodium content in all depths except for the depth of 100-150 cm. Irrigation with the treated wastewater did not affect the soil pH and nitrogen content significantly.

  11. Effective protective surveillance for waterside-located chemical plants

    NASA Astrophysics Data System (ADS)

    Love, John; Van Dover, Doug

    2006-05-01

    Millions of citizens live and work in the dangerous proximity of chemical plants, at ports and along waterways, which are under-protected and whose security is under-regulated, according to findings of the Congressional Research Service (CRS). There is a new and intense focus on the security of the nation's critical infrastructure. Thanks to recent philosophy and policy shifts within our federal government, the alarming situations in which we find ourselves will be mitigated somewhat a) by setting priorities based on proper threat analysis that considers event likelihoods and consequential impacts, and b) by employing effective systems design and engineering that will make it possible to address the highest priority threats with affordable solutions. It is the latter concern that we address, especially as it is relates to design and engineering of solutions for maintaining vigilance night and day. We begin by reviewing the nature of the facilities we wish to protect, our assumptions, and an accepted framework for analysis. Next we outline a hypothetical design case involving a representative facility and a plausible design basis threat. We then derive requirements for surveillance and examine the interrelationships among key design variables. Finally, we describe a solution involving multiple sensor types coupled with intelligent video. The end result is a significant increase in interdiction probability with a minimum of required assets.

  12. Effects of Temperature on Polymer/Carbon Chemical Sensors

    NASA Technical Reports Server (NTRS)

    Manfireda, Allison; Lara, Liana; Homer, Margie; Yen, Shiao-Pin; Kisor, Adam; Ryan, Margaret; Zhou, Hanying; Shevade, Abhijit; James, Lim; Manatt, Kenneth

    2009-01-01

    Experiments were conducted on the effects of temperature, polymer molecular weight, and carbon loading on the electrical resistances of polymer/carbon-black composite films. The experiment were performed in a continuing effort to develop such films as part of the JPL Electronic Nose (ENose), that would be used to detect, identify, and quantify parts-per-million (ppm) concentration levels of airborne chemicals in the space shuttle/space station environments. The polymers used in this study were three formulations of poly(ethylene oxide) [PEO] that had molecular weights of 20 kilodaltons, 600 kilodaltons, and 1 megadalton, respectively. The results of one set of experiments showed a correlation between the polymer molecular weight and the percolation threshold. In a second set of experiments, differences among the temperature dependences of resistance were observed for different carbon loadings; these differences could be explained by a change in the conduction mechanism. In a third set of experiments, the responses of six different polymer/carbon composite sensors to three analytes (water vapor, methanol, methane) were measured as a function of temperature (28 to 36 C). For a given concentration of each analyte, the response of each sensor decreased with increasing temperature, in a manner different from those of the other sensors.

  13. Thermal and chemical effects of turkey feathers pyrolysis.

    PubMed

    Kluska, Jacek; Kardaś, Dariusz; Heda, Łukasz; Szumowski, Mateusz; Szuszkiewicz, Jarosław

    2016-03-01

    This study examines the thermal and chemical effects of the pyrolysis of turkey feathers. Research of feathers pyrolysis is important because of their increasing production and difficulties of their utilization. The experiments were carried out by means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and two pyrolytic reactors. The experimental investigation indicated that the feather material liquefies at temperatures between 210 and 240°C. This liquefaction together with the agglomeration of various dispersed and porous elements of the feathers into larger droplets leads to the volume reduction. Moreover, this work presents characteristics of the composition of the solid, liquid and gaseous products of turkey feathers pyrolysis at different temperatures. The higher heating value (HHV) of gaseous products in temperature 900°C equals 19.28 MJ/Nm(3) making the gases suitable for use as a fuel. The thermochemical conversion of turkey feathers leads to the formation of poisonous compounds such as hydrogen cyanide (HCN) in the liquid (0.13%) and gaseous (88 mg/Nm(3)) products. The phenomenon of liquefaction of feathers is important because it can lead to rapid degradation of the walls of reactors, and the formation of deposits. PMID:26783100

  14. Physical and chemical pressure effects on magnetic spinels

    NASA Astrophysics Data System (ADS)

    Kiswandhi, Andhika O.

    Transition metal oxides and chalcogenides have been the major focus of studies in condensed matter physics. The complexity of the system, involving spin and orbital effects, as well as lattice degree of freedom, makes them intriguing subjects not only because of these individual effects, but also the effects due to the interaction among them. In AB2X4 materials (A = Mn2+, Co2+, Fe2+; B = V3+, Cr3+; X = O2--, S2--) which crystallize in spinel structure (space group Fd3m), these effects and their interactions manifest in their transport properties, magnetic ordering, itinerant electron magnetism, structural distortion, and geometrical frustration effect due to the antiferromagnetically coupled B-sites. These effects are dependent on the distance between the interacting cations, which can be varied by chemical substitution or pressure. The main objective of this dissertation is to study the physical properties of Mott-insulator spinels in approaching their critical inter-cationic distances where an insulator-metal transition occurs. Studying the insulator-metal transition in Mott insulators is important in advancing our understanding, especially in the field of fundamental physics and materials engineering, on the intricate relationships between the transport and magnetic properties and the emergence of new behaviors that arise from such properties in these materials. In this dissertation, the behavior of the physical properties of Mn 1--xCoxV2O4, AV2O 4 (A = Cd, Mg, Zn), and the transport properties of FeCr2S 4 in approaching the insulator-metal transition are reported. Mn 1--xCoxV2O4, AV2O 4, and FeCr2S4 are chosen for this study due to their dominant V-V or Cr-Cr interactions, which are responsible for their transport properties. In Mn1--xCoxV2O 4, the vanadium-vanadium distance is varied by means of chemical pressure (chemical substitution) to bring the system closer to the itinerant electron limit given by the critical V-V distance of 2.94 A. In Mn1--x CoxV2O4

  15. Dissecting the Mechanisms of a Class of Chemical Glycosylation Using Primary 13C Kinetic Isotope Effects

    PubMed Central

    Huang, Min; Garrett, Graham E.; Birlirakis, Nicolas; Bohé, Luis

    2012-01-01

    Although arguably the most important reaction in glycoscience, chemical glycosylations are among the least well understood of organic chemical reactions resulting in an unnecessarily high degree of empiricism and a brake on rational development in this critical area. To address this problem primary 13C kinetic isotope effects now have been determined for the formation of β- and α-manno- and glucopyranosides by a natural abundance NMR method. In contrast to the common current assumption, for three of the four cases studied the experimental values concur with those computed for associative displacement of the intermediate covalent glycosyl trifluoromethanesulfonates. For the formation of the α-mannopyranosides the experimentally determined KIE differs significantly from that computed for an associative displacement, which is strongly suggestive of a dissociative mechanism that approaches the intermediacy of a glycosyl oxocarbenium ion. The application of comparable experiments to other glycosylation systems should shed further light on their glycosylation mechanisms and thus assist in the design of better reactions conditions with improved stereoselectivity. PMID:22824899

  16. Dissecting the mechanisms of a class of chemical glycosylation using primary 13C kinetic isotope effects

    NASA Astrophysics Data System (ADS)

    Huang, Min; Garrett, Graham E.; Birlirakis, Nicolas; Bohé, Luis; Pratt, Derek A.; Crich, David

    2012-08-01

    Although arguably the most important reaction in glycoscience, chemical glycosylations are among the least well understood of organic chemical reactions, resulting in an unnecessarily high degree of empiricism and a brake on rational development in this critical area. To address this problem, primary 13C kinetic isotope effects have now been determined for the formation of β- and α-manno- and glucopyranosides using a natural abundance NMR method. In contrast to the common current assumption, for three of the four cases studied the experimental and computed values are indicative of associative displacement of the intermediate covalent glycosyl trifluoromethanesulfonates. For the formation of the α-mannopyranosides, the experimentally determined KIE differs significantly from that computed for an associative displacement, which is strongly suggestive of a dissociative mechanism that approaches the intermediacy of a glycosyl oxocarbenium ion. The application of analogous experiments to other glycosylation systems should shed further light on their mechanisms and thus assist in the design of better reactions conditions with improved stereoselectivity.

  17. Effect of chemical modifications on allergenic potency of peanut proteins

    PubMed Central

    Bencharitiwong, Ramon; van der Kleij, Hanneke P.M.; Koppelman, Stef J.

    2015-01-01

    Background: Modification of native peanut extracts could reduce adverse effects of peanut immunotherapy. Objective: We sought to compare native and chemically modified crude peanut extract (CPE) and major peanut allergens Ara h 2 and Ara h 6 in a mediator-release assay based on the rat basophilic leukemia (RBL) cell line transfected with human Fcε receptor. Methods: Native Ara h 2/6 was reduced and alkylated (RA), with or without additional glutaraldehyde treatment (RAGA). CPE was reduced and alkylated. Sera of subjects with peanut allergy (16 males; median age 7 years) were used for overnight RBL-passive sensitization. Cells were stimulated with 0.1 pg/mL to 10 μg/mL of peanut. β-N-acetylhexosaminidase release (NHR) was used as a marker of RBL degranulation, expressed as a percentage of total degranulation caused by Triton X. Results: Median peanut-specific immunoglobulin E was 233 kUA/L. Nineteen subjects were responders, NHR ≥ 10% in the mediator release assay. Responders had reduced NHR by RA and RAGA compared with the native Ara h 2/6. Modification resulted in a later onset of activation by 10- to 100-fold in concentration and a lowering of the maximum release. Modified RA-Ara h 2/6 and RAGA-Ara h 2/6 caused significantly lower maximum mediator release than native Ara h 2/6, at protein concentrations 0.1, 1, and 10 ng/mL (p < 0.001, < 0.001, and < 0.001, respectively, for RA; and < 0.001, 0.026, and 0.041, respectively, for RAGA). RA-CPE caused significantly lower maximum NHR than native CPE, at protein concentration 1 ng/mL (p < 0.001) and 10 ng/mL (p < 0.002). Responders had high rAra h 2 immunoglobulin E (mean, 61.1 kUA/L; p < 0.001) and higher NHR in mediator release assay to native Ara h 2/6 than CPE, which indicates that Ara h 2/6 were the most relevant peanut allergens in these responders. Conclusions: Chemical modification of purified native Ara h 2 and Ara h 6 reduced mediator release in an in vitro assay ∼100-fold, which indicates decreased

  18. Locally Derived Sediment, Yet Chemically and Chronologically Unique - Overcoming the "Stepladder Effect" in Provenance Studies

    NASA Astrophysics Data System (ADS)

    Bonich, M. B.; Samson, S. D.; Fedo, C.

    2014-12-01

    The trace element composition of clastic sedimentary rocks has frequently been used to characterize sediment provenance. To test the efficacy of whole-rock chemical composition as a provenance indicator, researchers examined alluvium solely derived from the 74 Ma Stepladder pluton (SP), in the Mojave Desert of SE California. Despite the low degree of chemical alteration and minimal transport distance neither trace element concentration or immobile elements ratios accurately reflected that of the source pluton. Furthermore, there is a considerable discrepancy between the frequency of zircon U-Pb ages from the SP and its derived alluvium. The majority (~ 75%) of the zircon grains from the SP are ~ 74 Ma and the remaining 25% are ~ 1.65 Ga. In contrast, ~ 50 to 85% of the detrital zircon, of varying grain sizes, yielded Proterozoic ages. Both the Kolmogorov-Smirnov (KS) and Likeness tests were used to compare all 120 possible samples pairs; the KS test rejected the null hypothesis that the zircon are derived from the same population, and the likeness test showed that most sediments are not like the source. These results, which we refer to as the "Stepladder effect", led us to consider Sr isotopic composition as a potentially more robust metric of provenance. Several of the sediment samples have similar present-day 87Sr/86Sr to that determined for four SP samples which range from 0.71055 to 0.71129. However, three sediment samples are distinctly different, suggesting a sedimentary sorting effect (e.g. concentration of biotite in finer sediments). To minimize this confounding effect we will determine the Sr isotopic composition of detrital apatite and biotite to compare with the same minerals of SP source. Using these specific minerals, which represent end-members of Rb-Sr spectrum, may help to constrain the degree of mixing with an externally sourced material (e.g. aeolian-derived grains) that have been added to the alluvium shedding further light on the Stepladder

  19. Unified studies of chemical bonding structures and resonant scattering in light neutron-excess systems, 10,12Be.

    PubMed

    Ito, Makoto; Ikeda, Kiyomi

    2014-09-01

    The generalized two-center cluster model (GTCM), which can treat covalent, ionic and atomic configurations in general systems with two inert cores plus valence nucleons, is formulated in the basis of the microscopic cluster model. In this model, the covalent configurations constructed by the molecular orbital (MO) method and the atomic (or ionic) configuration obtained by the valence bonding (VB) method can be handled in a consistent manner. The GTCM is applied to the light neutron-rich system (10,12)Be = α + α + Xn (X = 2, 4). The continuous and smooth changes of the neutron orbits from the covalent MO states to the ionic VB states are clearly observed in the adiabatic energy surfaces (AESs), which are the energy curves obtained with a variation of the α-α distance. The energy levels obtained from the AESs nicely reproduce the recent observations over a wide energy region. The individual spectra are characterized in terms of chemical-bonding-like structures, such as the covalent MO or ionic VB structures, according to analysis of their intrinsic wave functions. From the analysis of AESs, the formation of the mysterious 0(2)(+) states in (10,12)Be, which have anomalously small excitation energies in comparison to a naive shell-model prediction, is investigated. A large enhancement in a monopole transition from a ground MO state to an ionic α + (6,8)He VB state is found, which seems to be consistent with a recent observation. In the unbound region, the structure problem, which handles the total system of α + α + Xn (X = 2, 4) as a bound or quasi-bound state, and the reaction problem, induced by the collision of an asymptotic VB state of α + (6,8)He, are combined by the GTCM. The properties of unbound resonant states are discussed in close connection to the reaction mechanism, and some enhancement factors originating from the properties of the intrinsic states are predicted in the reaction observables. PMID:25222183

  20. The effect of a green and blue monochromatic light combination on broiler growth and development.

    PubMed

    Rozenboim, I; Biran, I; Chaiseha, Y; Yahav, S; Rosenstrauch, A; Sklan, D; Halevy, O

    2004-05-01

    Previous reports have suggested that green light enhances broiler growth at an early age, whereas blue light enhances growth at older ages. The aim of this study was to examine the effect of a switch in monochromatic light at 2 ages on growth and development of broilers. Male chicks (Anak, n = 640) were used. After hatch, chicks were weighed, wing-banded, and blocked into treatment groups. Chicks were grown in 1-m2 pens in 8 isolated light-proof rooms (20 birds/pen). The light treatments were (1) Control white (mini-incandescent lamps), 2) blue light-emitting diode (LED) lamps, 3) green LED lamps, 4) blue LED switching to green at 10 d of age, 5) blue LED switching to green at 20 d of age, 6) green LED switching to blue at 10 d of age, and 7) green LED switching to blue at 20 d of age. There were 8 pens for treatment 1, and 4 pens for each of the other treatments. The light schedule was 23L:1D, and intensity was 0.1 watts/m2. BW and feed consumption were recorded. Green light birds were significantly heavier at 4 d of age. Switching light at 10 d of age from green to blue caused a further increase in BW. This improved growth was maintained until the end of the experiment. Light switching from blue to green at 20 d of age also improved growth as compared with white light. Average feed efficiency and mortality rate did not differ between groups. No association was observed among light treatment, performance, and plasma triiodothyronine concentration. We suggest that green light stimulated growth of birds at early age, and shifting birds to a different light environment at 10 or 20 d of age might further stimulate growth. PMID:15141845

  1. Climatic and Chemical Effects of Punctuated Volcanism on Early Mars

    NASA Astrophysics Data System (ADS)

    Halevy, I.; Head, J. W.

    2012-12-01

    The geological record of Mars shows a pronounced peak in volcanic activity during the transition between the late Noachian and early Hesperian epochs. This peak appears coeval with profound climatic and chemical changes in the surface environment, including the formation of the majority of known valley networks, open-basin lakes and the deposition of massive sulfate-bearing deposits of aqueous origin. It has been suggested that volcanism maintained a warmer climate and an active hydrological cycle through the radiative effect of volcanically emitted greenhouse gases, such as CO2, H2O and SO2. However, previous model attempts at explaining overland flow with CO2-H2O greenhouse atmospheres required several bars of CO2, even including the warming effect of infrared scattering by CO2 ice clouds. This amount of CO2 is in apparent disagreement with recent estimates of volcanic outgassing on Mars. The net climatic effect of volcanic SO2 emissions into the atmosphere of early Mars has been the topic of recent debate, because it is unclear whether strong greenhouse warming by SO2 or strong cooling by scattering sulfate aerosols should dominate. To address this problem, we considered two previously neglected phenomena: i) the punctuated, rather than continuous, nature of volcanic eruptions, and ii) the role of preexisting dust grains and volcanic ash as condensation nuclei for sulfuric acid. For this purpose we developed a coupled model of volcanic eruption and atmospheric response, including detailed aerosol microphysics. We find that while SO2 concentrations increase rapidly and dramatically with the initiation of a strong volcanic eruption, the dynamics of sulfate aerosol formation in the martian atmosphere results in a delay of aerosol-related cooling by several months to years. Moreover, the existence of dust in the atmosphere prior to the volcanic eruption, as well as the emission and global distribution of fine volcanic ash particles, results in the formation of H2SO4

  2. Strong geometrical effects in submillimeter selective area growth and light extraction of GaN light emitting diodes on sapphire

    DOE PAGESBeta

    Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; Dayeh, Shadi A.

    2015-11-27

    Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. Our detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates is reported here, and we utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO2. We show that the mask opening diameter leads to as much as 4 times increase inmore » the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We also observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Lastly, such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures.« less

  3. Strong Geometrical Effects in Submillimeter Selective Area Growth and Light Extraction of GaN Light Emitting Diodes on Sapphire

    PubMed Central

    Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; Dayeh, Shadi A.

    2015-01-01

    Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. We report here detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates and utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO2. We show that the mask opening diameter leads to as much as 4 times increase in the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures. PMID:26611405

  4. Strong geometrical effects in submillimeter selective area growth and light extraction of GaN light emitting diodes on sapphire

    SciTech Connect

    Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; Dayeh, Shadi A.

    2015-11-27

    Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. Our detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates is reported here, and we utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO2. We show that the mask opening diameter leads to as much as 4 times increase in the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We also observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Lastly, such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures.

  5. The effect of surface fog on the transmittance of light

    SciTech Connect

    Briscoe, B.J.; Galvin, K.P. )

    1991-01-01

    It is shown theoretically that surface fog can reduce the transmittance of normally incident light through transparent materials from about 90% to nearly 50%. This result is also confirmed experimentally by reflectance measurements. The most important parameter is the contact angle which the droplets make with the surface. For contact angles less than about 40{degree}, there is almost no loss in transmission. For larger contact angles, there is a significant decrease in the transmittance, with the worst case occurring for a contact angle of 90{degree}.

  6. The effect of photometric and geometric context on photometric and geometric lightness effects

    PubMed Central

    Lee, Thomas Y.; Brainard, David H.

    2014-01-01

    We measured the lightness of probe tabs embedded at different orientations in various contextual images presented on a computer-controlled stereo display. Two background context planes met along a horizontal roof-like ridge. Each plane was a graphic rendering of a set of achromatic surfaces with the simulated illumination for each plane controlled independently. Photometric context was varied by changing the difference in simulated illumination intensity between the two background planes. Geometric context was varied by changing the angle between them. We parsed the data into separate photometric effects and geometric effects. For fixed geometry, varying photometric context led to linear changes in both the photometric and geometric effects. Varying geometric context did not produce a statistically reliable change in either the photometric or geometric effects. PMID:24464163

  7. Light diffusing effects of nano and micro-structures on OLED with microcavity.

    PubMed

    Cho, Doo-Hee; Shin, Jin-Wook; Joo, Chul Woong; Lee, Jonghee; Park, Seung Koo; Moon, Jaehyun; Cho, Nam Sung; Chu, Hye Yong; Lee, Jeong-Ik

    2014-10-20

    We examined the light diffusing effects of nano and micro-structures on microcavity designed OLEDs. The results of FDTD simulations and experiments showed that the pillar shaped nano-structure was more effective than the concave micro-structure for light diffusing of microcavity OLEDs. The sharp luminance distribution of the microcavity OLED was changed to near Lambertian luminance distribution by the nano-structure, and light diffusing effects increased with the height of the nano-structure. Furthermore, the nano-structure has advantages including light extraction of the substrate mode, reproducibility of manufacturing process, and minimizing pixel blur problems in an OLED display panel. The nano-structure is a promising candidate for a light diffuser, resolving the viewing angle problems in microcavity OLEDs. PMID:25607307

  8. The Chemical Aquatic Fate and Effects database (CAFE), a tool that supports assessments of chemical spills in aquatic environments.

    PubMed

    Bejarano, Adriana C; Farr, James K; Jenne, Polly; Chu, Valerie; Hielscher, Al

    2016-06-01

    The Chemical Aquatic Fate and Effects (CAFE) database is a centralized repository that allows for rapid and unrestricted access to data. Information in CAFE is integrated into a user-friendly tool with modules containing fate and effects data for 32 377 and 4498 chemicals, respectively. Toxicity data are summarized in the form of species sensitivity distributions (SSDs) with associated 1st and 5th percentile hazard concentrations (HCs). An assessment of data availability relative to reported chemical incidents showed that CAFE had fate and toxicity data for 32 and 20 chemicals, respectively, of 55 chemicals reported in the US National Response Center database (2000-2014), and fate and toxicity data for 86 and 103, respectively, of 205 chemicals reported by the National Oceanic and Atmospheric Administration (2003-2014). Modeled environmental concentrations of 2 hypothetical spills (acrylonitrile, 625 barrels; and denatured ethanol, 857 barrels) were used to demonstrate CAFE's practical application. Most species in the 24-h SSD could be potentially impacted by acrylonitrile and denatured ethanol during the first 35 min and 15 h post spill, respectively, with concentrations falling below their HC5s (17 mg/L and 2676 mg/L) at 45 min and 60 h post spill, respectively. Comparisons of CAFE-based versus published HC5 values for 100 chemicals showed that nearly half of values were within a 2-fold difference, with a relatively small number of comparisons exceeding a 10-fold difference. The development of CAFE facilitates access to relevant environmental information, with potential uses likely expanding beyond those related to assessment of spills in aquatic environments. Environ Toxicol Chem 2016;35:1576-1586. © 2015 SETAC. PMID:26497000

  9. Cumulative effects of anti-androgenic chemical mixtures and their relevance to human health risk assessment

    EPA Science Inventory

    Kembra L. Howdeshell and L. Earl Gray, Jr.Toxicological studies of defined chemical mixtures assist human health risk assessment by characterizing the joint action of chemicals. This presentation will review the effects of anti-androgenic chemical mixtures on reproductive tract d...

  10. A Novel Effect of Scattered-Light Interference in Misted Mirrors

    ERIC Educational Resources Information Center

    Bridge, N. James

    2005-01-01

    Interference rings can be observed in mirrors clouded by condensation, even in diffuse lighting. The effect depends on individual droplets acting as point sources by refracting light into the mirror, so producing coherent wave-trains which are reflected and then scattered again by diffraction round the same source droplet. The secondary wave-train…

  11. Effects of light intensity, oxygen concentration, and carbon dioxide concentration on photosynthesis in algae.

    PubMed

    Pope, D H

    1975-03-01

    The effects of various combinations of light intensity, oxygen concentration, and CO2 concentration on photosynthesis and growth in several algal types were studied. The results suggest the following. (1) Different algae show different responses to high oxygen concentrations and high light intensities. (2) Inhibition of photosynthesis (CO2 fixation and growth), if seen, increases with increasing oxygen concentration and with increasing light intensity (at light intensities greater than saturation). (3) The inhibition of net photosynthesis observed cannot be attributed to high light intensity alone. (4) The inhibition cannot be attributed to increased rates of excretion of organic materials under conditions of high oxygen concentration and high light intensity. (5) Increased concentrations of CO2 can decrease the effect of high oxygen and light in some algae. (6) The decrease in net photosynthesis observed is probably the result of photorespiration. (7) The effect of light intensity, oxygen concentration, or CO2 concentration on algal photosynthesis should not be studied without considering the effect of the other factors. Some implications of these results, as related to primary productivity measurements, are also discussed. PMID:24241158

  12. The Effects on Visually Impaired Children of Viewing Fluorescent Stimuli under Black-Light Conditions.

    ERIC Educational Resources Information Center

    LaGrow, S. J.; Leung, J-P.; Leung, S.; Yeung, P.

    1998-01-01

    This study compared effects of four visual conditions of stimuli and light on the visual performance of 30 children with low vision (divided into high, and low, visual-acuity groups). Orange stimuli viewed under black light resulted in the best overall performance, benefitted the low-acuity group more than the high-acuity group, and was the…

  13. Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

    NASA Astrophysics Data System (ADS)

    Ji, Chen; Hernandez, Oscar Javier; Nevo Dinur, Nir; Bacca, Sonia; Barnea, Nir

    2016-03-01

    We present calculations of nuclear structure effects to the Lamb shift in light muonic atoms. We adopt a modern ab-initio approach by combining state-of-the-art nuclear potentials with the hyperspherical harmonics method. Our calculations are instrumental to the determination of nuclear charge radii in the Lamb shift measurements, which will shed light on the proton radius puzzle.

  14. Light-soaking effects on photoconductivity in a-Si:H thin films

    SciTech Connect

    Morgado, E.; Da Silva, M.R.; Henriques, R.T.

    1997-07-01

    Metastable defects have been created by light exposure in thin films of a-Si:H. The samples have been characterized by Photothermal Deflection Spectroscopy, Electron Spin Resonance, dark- and photo-conductivity. The experimental results are consistent with numerical calculations with a recombination model involving band tails and one class of correlated dangling-bond states. The effects of light-soaking on the light intensity and defect density dependences of photoconductivity are reproduced by the calculations. The model allows to explain the experimental trends by changes in the electronic occupation of the gap states produced by light-induced defects.

  15. Light Effect on Water Viscosity: Implication for ATP Biosynthesis

    NASA Astrophysics Data System (ADS)

    Sommer, Andrei P.; Haddad, Mike Kh.; Fecht, Hans-Jörg

    2015-07-01

    Previous work assumed that ATP synthase, the smallest known rotary motor in nature, operates at 100% efficiency. Calculations which arrive to this result assume that the water viscosity inside mitochondria is constant and corresponds to that of bulk water. In our opinion this assumption is not satisfactory for two reasons: (1) There is evidence that the water in mitochondria prevails to 100% as interfacial water. (2) Laboratory experiments which explore the properties of interfacial water suggest viscosities which exceed those of bulk water, specifically at hydrophilic interfaces. Here, we wish to suggest a physicochemical mechanism which assumes intramitochondrial water viscosity gradients and consistently explains two cellular responses: The decrease and increase in ATP synthesis in response to reactive oxygen species and non-destructive levels of near-infrared (NIR) laser light, respectively. The mechanism is derived from the results of a new experimental method, which combines the technique of nanoindentation with the modulation of interfacial water layers by laser irradiation. Results, including the elucidation of the principle of light-induced ATP production, are expected to have broad implications in all fields of medicine.

  16. Effects of acetic acid on light scattering from cells

    PubMed Central

    Marina, Oana C.; Sanders, Claire K.

    2012-01-01

    Abstract. Acetic acid has been used for decades as an aid for the detection of precancerous cervical lesions, and the use of acetic acid is being investigated in several other tissues. Nonetheless, the mechanism of acetowhitening is unclear. This work tests some of the hypotheses in the literature and measures changes in light scattering specific to the nucleus and the cytoplasm. Wide angle side scattering from both the nucleus and the cytoplasm increases with acetic application to tumorigenic cells, with the increase in nuclear scattering being greater. In one cell line, the changes in nuclear scattering are likely due to an increase in number or scattering efficiency of scattering centers smaller than the wavelength of excitation light. There are likely several cellular changes that cause acetowhitening and the cellular changes may differ with cell type. These results should lead to a better understanding of acetowhitening and potentially the development of adjunct techniques to improve the utility of acetic acid application. For the well-studied case of cervical tissue, acetowhitening has been shown to be sensitive, but not specific for oncogenic changes needing treatment. PMID:23224185

  17. Benthic effects on the polarization of light in shallow waters.

    PubMed

    Gilerson, Alexander A; Stepinski, Jan; Ibrahim, Amir I; You, Yu; Sullivan, James M; Twardowski, Michael S; Dierssen, Heidi M; Russell, Brandon; Cummings, Molly E; Brady, Parrish; Ahmed, Samir A; Kattawar, George W

    2013-12-20

    Measurements of the upwelling polarized radiance in relatively shallow waters of varying depths and benthic conditions are compared to simulations, revealing the depolarizing nature of the seafloor. The simulations, executed with the software package RayXP, are solutions to the vector radiative transfer equation, which depends on the incident light field and three types of parameters: inherent optical properties, the scattering matrix, and the benthic reflectance. These were measured directly or calculated from measurements with additional assumptions. Specifically, the Lambertian model used to simulate benthic reflectances is something of a simplification of reality, but the bottoms used in this study are found to be crucial for accurate simulations of polarization. Comparisons of simulations with and without bottom contributions show that only the former corroborate measurements of the Stokes components and the degree of linear polarization (DoLP) collected by the polarimeter developed at the City College of New York. Because this polarimeter is multiangular and hyperspectral, errors can be computed point-wise over a large range of scattering angles and wavelengths. Trends also become apparent. DoLP is highly sensitive to the benthic reflectance and to the incident wavelength, peaking in the red band, but the angle of linear polarization is almost spectrally constant and independent of the bottom. These results can thus facilitate the detection of benthic materials as well as future studies of camouflage by benthic biota; to hide underwater successfully, animals must reflect light just as depolarized as that reflected by benthic materials. PMID:24513934

  18. Light Effect on Water Viscosity: Implication for ATP Biosynthesis

    PubMed Central

    Sommer, Andrei P.; Haddad, Mike Kh.; Fecht, Hans-Jörg

    2015-01-01

    Previous work assumed that ATP synthase, the smallest known rotary motor in nature, operates at 100% efficiency. Calculations which arrive to this result assume that the water viscosity inside mitochondria is constant and corresponds to that of bulk water. In our opinion this assumption is not satisfactory for two reasons: (1) There is evidence that the water in mitochondria prevails to 100% as interfacial water. (2) Laboratory experiments which explore the properties of interfacial water suggest viscosities which exceed those of bulk water, specifically at hydrophilic interfaces. Here, we wish to suggest a physicochemical mechanism which assumes intramitochondrial water viscosity gradients and consistently explains two cellular responses: The decrease and increase in ATP synthesis in response to reactive oxygen species and non-destructive levels of near-infrared (NIR) laser light, respectively. The mechanism is derived from the results of a new experimental method, which combines the technique of nanoindentation with the modulation of interfacial water layers by laser irradiation. Results, including the elucidation of the principle of light-induced ATP production, are expected to have broad implications in all fields of medicine. PMID:26154113

  19. The contribution of the diffuse light component to the topographic effect on remotely sensed data

    NASA Technical Reports Server (NTRS)

    Justice, C.; Holben, B.

    1980-01-01

    The topographic effect is measured by the difference between the global radiance from inclined surfaces as a function of their orientation relative to the sensor position and light source. The short wave radiant energy incident on a surface is composed of direct sunlight, scattered skylight, and light reflected from surrounding terrain. The latter two components are commonly known as the diffuse component. The contribution of the diffuse light component to the topographic effect was examined and the significance of this diffuse component with respect to two direct radiance models was assessed. Diffuse and global spectral radiances were measured for a series of slopes and aspects of a uniform and surface in the red and photographic infrared parts of the spectrum, using a nadir pointing two channel handheld radiometer. The diffuse light was found to produce a topographic effect which varied from the topographic effect for direct light. The topographic effect caused by diffuse light was found to increase slightly with solar elevation and wavelength for the channels examined. The correlations between data derived from two simple direct radiance simulation models and the field data were not significantly affected when the diffuse component was removed from the radiances. Radiances from a 60 percent reflective surface, assuming no atmospheric path radiance, the diffuse light topographic effect contributed a maximum range of 3 pixel values in simulated LANDSAT data from all aspects with slopes up to 30 degrees.

  20. Simulations of light effects on the human circadian pacemaker: implications for assessment of intrinsic period

    NASA Technical Reports Server (NTRS)

    Klerman, E. B.; Dijk, D. J.; Kronauer, R. E.; Czeisler, C. A.

    1996-01-01

    The sensitivity of the human circadian system to light has been the subject of considerable debate. Using computer simulations of a recent quantitative model for the effects of light on the human circadian system, we investigated these effects of light during different experimental protocols. The results of the simulations indicate that the nonuniform distribution over the circadian cycle of exposure to ordinary room light seen in classical free-run studies, in which subjects select their exposure to light and darkness, can result in an observed period of approximately 25 h, even when the intrinsic period of the subject's endogenous circadian pacemaker is much closer to 24 h. Other simulation results suggest that accurate assessment of the true intrinsic period of the human circadian pacemaker requires low ambient light intensities (approximately 10-15 lx) during scheduled wake episodes, desynchrony of the imposed light-dark cycle from the endogenous circadian oscillator, and a study length of at least 20 days. Although these simulations await further experimental substantiation, they highlight the sensitivity to light of the human circadian system and the potential confounding influence of light on the assessment of the intrinsic period of the circadian pacemaker.

  1. The effect of light direction and suspended cell concentrations on algal biofilm growth rates.

    PubMed

    Schnurr, Peter J; Espie, George S; Allen, D Grant

    2014-10-01

    Algae biofilms were grown in a semicontinuous flat plate biofilm photobioreactor to study the effects of light direction and suspended algal cell populations on algal biofilm growth. It was determined that, under the growth conditions and biofilm thicknesses studied, light direction had no effect on long-term algal biofilm growth (26 days); however, light direction did affect the concentration of suspended algal cells by influencing the photon flux density in the growth medium in the photobioreactors. This suspended algal cell population affected short-term (7 days) algae cell recruitment and algal biofilm growth, but additional studies showed that enhanced suspended algal cell populations did not affect biofilm growth rates over the long term (26 days). Studying profiles of light transmittance through biofilms as they grew showed that most of the light became attenuated by the biomass after just a few days of growth (88 % after 3 days). The estimated biofilm thicknesses after these few days of growth were approximately 150 μm. The light attenuation data suggests that, although the biofilms grew to 700-900 μm, under these light intensities, only the first few hundred micrometers of the biofilm is receiving enough light to be photosynthetically active. We postulate that this photosynthetically active layer of the biofilm grows adjacent to the light source, while the rest of the biofilm is in a stationary growth phase. The results of this study have implications for algal biofilm photobioreactor design and operation. PMID:25149444

  2. Effects of light wavelength on MEG ERD/ERS during a working memory task.

    PubMed

    Okamoto, Yosuke; Nakagawa, Seiji

    2016-06-01

    We investigated the effects of light wavelengths on cortical oscillatory activity associated with working memory processes. Cortical activity responses were measured using magnetoencephalography (MEG) while participants performed an auditory Sternberg memory task during exposure to light of different wavelength. Each trial of the memory task consisted of four words presented as a memory set and one word presented as a probe. All words were presented audibly. Participants were instructed to indicate whether the probe word was or was not presented within the memory set. A total of 90 trials were conducted under the light exposure. Event-related synchronization (ERS) and event-related desynchronization responses in the alpha frequency range during the task were analyzed. Results showed that, during memory encoding, ERS responses were significantly greater in the short-wavelength (blue) light condition than in the middle-wavelength (green) light condition, approximately 20-30min after the onset of light exposure. Behavioral performance was very high throughout the experiment and there was no difference between the light conditions. Although the light effects were not observed in behavior, the result of ERS suggests that 20-30min of exposure to blue light enhances cortical activity related to active memory maintenance and/or attention to auditory stimuli. PMID:27040560

  3. The Effect of Environmental Chemicals on Human Health -- CJA

    EPA Science Inventory

    Humans and animals have always been exposed to chemicals in our environment - natural products in foods, smoke from cooking fires, sewage in drinking water, pesticides from plants. However, the dramatic increases in industrialization over the past three centuries have dramatical...

  4. THE EFFECT OF ENVIRONMENTAL CHEMICALS ON HUMAN HEALTH -- USCF

    EPA Science Inventory

    Humans and animals have always been exposed to chemicals in our environment - natural products in foods, smoke from cooking fires, sewage in drinking water, pesticides from plants. However, the dramatic increases in industrialization over the past three centuries have dramatical...

  5. THE EFFECT OF ENVIRONMENTAL CHEMICALS ON HUMAN HEALTH

    EPA Science Inventory

    Humans and animals have always been exposed to chemicals in our environments - natural products in foods, smoke from cooking fires, sewage in drinking water, pesticides from plants. However, the dramatic increases in industrialization over the past three centuries have dramatica...

  6. Effect of chemical polishing in titanium materials for low outgassing

    NASA Astrophysics Data System (ADS)

    Ishizawa, K.; Kurisu, H.; Yamamoto, S.; Nomura, T.; Murashige, N.

    2008-03-01

    A chemical polishing using a nitric acid solution was found to be the most suitable for the titanium materials. 1.8 nm of small surface roughness was observed in a microscopic range in 1 μm square, and 7 nm of a thin oxide layer was shown to exist for the chemically polished titanium. The surface processing for the titanium was developed combining the chemical polishing and the precision cleaning. The chemically polished pure titanium of JIS grade 2 showed extremely low outgassing rate below 10-12 Pams-1 after baking process, which is two orders of magnitude smaller than that for standard vacuum materials under the same baking condition. Outgassing rates of the titanium is about 1/5 of that for a stainless steel without baking process.

  7. Chemical fingerprinting of Shexiang Baoxin Pill and simultaneous determination of its major constituents by HPLC with evaporative light scattering detection and electrospray mass spectrometric detection.

    PubMed

    Yan, Shi-Kai; Zhang, Wei-Dong; Liu, Run-Hui; Zhan, Yong-Cheng

    2006-07-01

    High-performance Liquid Chromatography (HPLC) with evaporative light scattered detection (ELSD) and electrospray ionization mass spectrometric detection (ESI-MS) was employed to establish chemical fingerprint of Shexiang Baoxin Pill (SBP) and to simultaneously determinate its seven major constituents, including cholic acid, deoxycholic acid, ursodeoxycholic acid, chenodeoxycholic acid, cinobufagin, recibufogenin, and ginsenoside Rb1. The analysis was performed on a C18 column with water-acetonitrile gradient elution, and the investigated constituents were authenticated by comparing their retention times and mass spectra with those of reference compounds. The proposed method was applied to analyze nine SBP samples and produced data with acceptable linearity, precision, stability and accuracy. Both the chemical fingerprints and quantification data were used to evaluate the quality of various SBP products. The proposed method allows obtaining chemical fingerprint and quantification of multi-components in one run, and therefore can be readily utilized as a comprehensive quality control approach for traditional Chinese medicine. PMID:16819233

  8. A new index to assess chemicals increasing the greenhouse effect based on their toxicity to algae.

    PubMed

    Wang, Ting; Zhang, Xiaoxian; Tian, Dayong; Gao, Ya; Lin, Zhifen; Liu, Ying; Kong, Lingyun

    2015-11-01

    CO2, as the typical greenhouse gas causing the greenhouse effect, is a major global environmental problem and has attracted increasing attention from governments. Using algae to eliminate CO2, which has been proposed as an effective way to reduce the greenhouse effect in the past decades, can be disturbed by a growing number of artificial chemicals. Thus, seven types of chemicals and Selenastrum capricornutum (algae) were examined in this study, and the good consistency between the toxicity of artificial chemicals to algae and the disturbance of carbon fixation by the chemicals was revealed. This consistency showed that the disturbance of an increasing number of artificial chemicals to the carbon fixation of algae might be a "malware" worsening the global greenhouse effect. Therefore, this study proposes an original, promising index to assess the risk of deepening the greenhouse effect by artificial chemicals before they are produced and marketed. PMID:26520250

  9. Physico-chemical properties and biological effects of diesel and biomass particles.

    PubMed

    Longhin, Eleonora; Gualtieri, Maurizio; Capasso, Laura; Bengalli, Rossella; Mollerup, Steen; Holme, Jørn A; Øvrevik, Johan; Casadei, Simone; Di Benedetto, Cristiano; Parenti, Paolo; Camatini, Marina

    2016-08-01

    Diesel combustion and solid biomass burning are the major sources of ultrafine particles (UFP) in urbanized areas. Cardiovascular and pulmonary diseases, including lung cancer, are possible outcomes of combustion particles exposure, but differences in particles properties seem to influence their biological effects. Here the physico-chemical properties and biological effects of diesel and biomass particles, produced under controlled laboratory conditions, have been characterized. Diesel UFP were sampled from a Euro 4 light duty vehicle without DPF fuelled by commercial diesel and run over a chassis dyno. Biomass UFP were collected from a modern automatic 25 kW boiler propelled by prime quality spruce pellet. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of both diesel and biomass samples showed aggregates of soot particles, but in biomass samples ash particles were also present. Chemical characterization showed that metals and PAHs total content was higher in diesel samples compared to biomass ones. Human bronchial epithelial (HBEC3) cells were exposed to particles for up to 2 weeks. Changes in the expression of genes involved in xenobiotic metabolism were observed after exposure to both UFP already after 24 h. However, only diesel particles modulated the expression of genes involved in inflammation, oxidative stress and epithelial-to-mesenchymal transition (EMT), increased the release of inflammatory mediators and caused phenotypical alterations, mostly after two weeks of exposure. These results show that diesel UFP affected cellular processes involved in lung and cardiovascular diseases and cancer. Biomass particles exerted low biological activity compared to diesel UFP. This evidence emphasizes that the study of different emission sources contribution to ambient PM toxicity may have a fundamental role in the development of more effective strategies for air quality improvement. PMID:27194366

  10. The Effect of Neutrino Oscillations on Supernova Light Element Synthesis

    SciTech Connect

    Yoshida, Takashi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H.

    2006-07-12

    We investigate light element synthesis through the {nu}-process during supernova explosions considering neutrino oscillations and investigate the dependence of 7Li and 11B yields on neutrino oscillation parameters mass hierarchy and {theta}13. The adopted supernova explosion model for explosive nucleosynthesis corresponds to SN 1987A. The 7Li and 11B yields increase by about factors of 1.9 and 1.3 in the case of normal mass hierarchy and adiabatic 13-mixing resonance compared with the case without neutrino oscillations. In the case of inverted mass hierarchy or nonadiabatic 13-mixing resonance, the increase in 7Li and 11B yields is much smaller. Astronomical observations of 7Li/11B ratio in stars formed in regions strongly affected by prior generations of supernovae would constrain mass hierarchy and the range of {theta}13.

  11. Light induced tunnel effect in CNT-Si photodiode

    NASA Astrophysics Data System (ADS)

    Aramo, C.; Ambrosio, M.; Bonavolontà, C.; Boscardin, M.; Castrucci, P.; Crivellari, M.; De Crescenzi, M.; de Lisio, C.; Fiandrini, E.; Grossi, V.; Maddalena, P.; Passacantando, M.; Santucci, S.; Scarselli, M.; Valentini, A.; Valentino, M.

    2016-07-01

    Negative differential resistance (NDR), for which the current is a decreasing function of the voltage, has been observed in the current-voltage curves of several types of structures. We measured tunnelling current and NDR by illuminating large area heterojunction obtained by growing Multi Wall Carbon Nanotubes on the surface of n-doped Silicon substrate. In the absence of light, the current flow is null until a junction threshold of about 2.4 V is reached, beyond which the dark current flows at room temperature with a very low intensity of few nA. When illuminated, a current of tens nA is observed at a drain voltage of about 1.5 V. At higher voltage the current intensity decreases according to a negative resistance of the order of MΩ. In the following we report details of tunneling photodiode realized and negative resistance characteristics.

  12. Light-induced pyroelectric effect as an effective approach for ultrafast ultraviolet nanosensing

    NASA Astrophysics Data System (ADS)

    Wang, Zhaona; Yu, Ruomeng; Pan, Caofeng; Li, Zhaoling; Yang, Jin; Yi, Fang; Wang, Zhong Lin

    2015-09-01

    Zinc oxide is potentially a useful material for ultraviolet detectors; however, a relatively long response time hinders practical implementation. Here by designing and fabricating a self-powered ZnO/perovskite-heterostructured ultraviolet photodetector, the pyroelectric effect, induced in wurtzite ZnO nanowires on ultraviolet illumination, has been utilized as an effective approach for high-performance photon sensing. The response time is improved from 5.4 s to 53 μs at the rising edge, and 8.9 s to 63 μs at the falling edge, with an enhancement of five orders in magnitudes. The specific detectivity and the responsivity are both enhanced by 322%. This work provides a novel design to achieve ultrafast ultraviolet sensing at room temperature via light-self-induced pyroelectric effect. The newly designed ultrafast self-powered ultraviolet nanosensors may find promising applications in ultrafast optics, nonlinear optics, optothermal detections, computational memories and biocompatible optoelectronic probes.

  13. New auxin analogs with growth-promoting effects in intact plants reveal a chemical strategy to improve hormone delivery

    PubMed Central

    Savaldi-Goldstein, Sigal; Baiga, Thomas J.; Pojer, Florence; Dabi, Tsegeye; Butterfield, Cristina; Parry, Geraint; Santner, Aaron; Dharmasiri, Nihal; Tao, Yi; Estelle, Mark; Noel, Joseph P.; Chory, Joanne

    2008-01-01

    Plant growth depends on the integration of environmental cues and phytohormone-signaling pathways. During seedling emergence, elongation of the embryonic stem (hypocotyl) serves as a readout for light and hormone-dependent responses. We screened 10,000 chemicals provided exogenously to light-grown seedlings and identified 100 compounds that promote hypocotyl elongation. Notably, one subset of these chemicals shares structural characteristics with the synthetic auxins, 2,4-dichlorophenoxyacetic acid (2,4-D), and 1-naphthaleneacetic acid (1-NAA); however, traditional auxins (e.g., indole-3-acetic acid [IAA], 2,4-D, 1-NAA) have no effect on hypocotyl elongation. We show that the new compounds act as “proauxins” akin to prodrugs. Our data suggest that these compounds diffuse efficiently to the hypocotyls, where they undergo cleavage at varying rates, releasing functional auxins. To investigate this principle, we applied a masking strategy and designed a pro-2,4-D. Unlike 2,4-D alone, this pro-2,4-D enhanced hypocotyl elongation. We further demonstrated the utility of the proauxins by characterizing auxin responses in light-grown hypocotyls of several auxin receptor mutants. These new compounds thus provide experimental access to a tissue previously inaccessible to exogenous application of auxins. Our studies exemplify the combined power of chemical genetics and biochemical analyses for discovering and refining prohormone analogs with selective activity in specific plant tissues. In addition to the utility of these compounds for addressing questions related to auxin and light-signaling interactions, one can envision using these simple principles to study other plant hormone and small molecule responses in temporally and spatially controlled ways. PMID:18818305

  14. An assessment of the effects of crude oil pollution on soil properties, germination and growth of maize (Zea mays) using two crude types--Forcados light and Escravos light.

    PubMed

    Ogboghodo, I A; Iruaga, E K; Osemwota, I O; Chokor, J U

    2004-01-01

    The effect of crude oil pollution on soil properties, germination and height of maize (Zea mays) was investigated under natural environment in three separate pot experiments. Two crude oil types--Forcados light and Escravos light were used. In Experiment 1, the effect of crude oil application on germination using high pollution levels of 5, 15, 25 and 40 mL kg(-1) of soil was assessed. In Experiment 2, the effect of crude oil application on maize plant height using the same pollution levels was assessed. The last experiment (Experiment 3) was used to test for the effects of crude oil application on maize plant height using lower levels of pollution (1.0, 1.5, 2.0 and 2.5 mL kg(-1) of soil). Soil samples were collected before, during and after the experiment and analyzed for some physical and chemical properties. Results obtained showed variation in chemical properties of soil. % organic matter increased from 1.34 to 2.62% in polluted soils. Available P decreased from 15.00 ppm in control to between 7.34 and 5.42 in soils polluted with 'high' levels of crude oil. Statistical analysis of height data showed that crude oil inhibited the growth of maize at high pollution levels. High levels of pollution also inhibited germination and for Escravos light there was no germination at 40 mL kg(-1) soil level of crude oil pollution. PMID:15327154

  15. A chemical mechanism to explain matrix effects in multi-collector ICP-MS

    NASA Astrophysics Data System (ADS)

    Mueller, B.

    2012-12-01

    A chemical mechanism is presented to explain many of the matrix effects observed in multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). It suggests that breakdown products of the ion exchange resins used to remove sample matrix co-elute with samples and subsequently contaminates the uptake tubing and nebulizer of the ICP-MS. The sample path then contains stationary ligands and acts as a mini-column causing memory or carry-over that lead to the observed matrix effects. The minicolumn mechanism is used to explain: variations in sensitivity between samples and standards, variations in sensitivity on the addition of inorganic or organic matrix, changes in mass bias on the addition of matrix elements or column matrix, the coupling of sensitivity changes with mass bias changes, light isotope backgrounds, changes in mass bias with changes in analyte concentration, the poor reproducibility of the matrix effects, the reduction of mass bias with increasing matrix load and variations in mass bias across isotopes of the same element.

  16. Exploring the performance of indoor localization systems based on VLC-RSSI, including the effect of NLOS components using two light-emitting diode lighting systems

    NASA Astrophysics Data System (ADS)

    Elkarim, Mohammed Abd; Mohammed, Nazmi A.; Aly, Moustafa H.

    2015-10-01

    We analyze the effect of diffuse reflection on indoor localization systems based on visible light communication. The target position is estimated using a received signal strength indication technique. Two lighting systems are considered: distinct and uniform lighting systems. Each utilizes commercially available light-emitting diodes and photodiodes with an illumination level conforming to standards. We introduce a comparative study between the two lighting systems through different transmitter (Tx) and receiver (Rx) essential parameters. The results show that the uniform lighting system achieves less localization error (≤20.43 cm) than a distinct lighting system (≤45.9 cm). The uniform lighting system is well adapted to low-Rx field of view (FOV) and narrow radiation angle (error=1 mm when semiradiation angle=5 deg). In the case of a distinct lighting system, low-Rx FOV is also required, while the Tx semiradiation angle needs to be determined carefully (error≤3.08 cm when semiradiation angle=20 deg). Finally, the uniform lighting system shows flexibility in the process of Tx and Rx designs. A uniform lighting system can utilize Rxs with narrow FOVs (≥8.6 deg), while a distinct lighting system is limited to Rx with a wide FOV (≥53.96 deg).

  17. The effects of light therapy on sleep problems: A systematic review and meta-analysis.

    PubMed

    van Maanen, Annette; Meijer, Anne Marie; van der Heijden, Kristiaan B; Oort, Frans J

    2016-10-01

    Although bright light therapy seems a promising treatment for sleep problems, research shows inconclusive results. This meta-analysis is the first to systematically review the effect of light therapy on sleep problems in general and on specific types of sleep problems in particular (circadian rhythm sleep disorders, insomnia, sleep problems related to Alzheimer's disease and dementia). Fifty-three studies with a total of 1154 participants were included. Overall effects and effects on separate circadian and sleep outcomes were examined. We calculated Hedges' g effect sizes and we investigated the effects of twelve moderators (design-related, treatment-related, participant-related). Light therapy was found effective in the treatment of sleep problems in general (g = 0.39), and for circadian rhythm sleep disorders (g = 0.41), insomnia (g = 0.47), and sleep problems related to Alzheimer's disease/dementia (g = 0.30) specifically. For circadian rhythm sleep disorders, effects were smaller for randomised controlled trials. For insomnia, we found larger effects for studies using a higher light intensity, and for sleep problems related to Alzheimer's disease/dementia larger effects were found for studies with more female participants. There was indication of publication bias. To conclude, light therapy is effective for sleep problems in general, particularly for circadian outcomes and insomnia symptoms. However, most effect sizes are small to medium. PMID:26606319

  18. Micromotors with asymmetric shape that efficiently convert light into work by thermocapillary effects

    PubMed Central

    Maggi, Claudio; Saglimbeni, Filippo; Dipalo, Michele; De Angelis, Francesco; Di Leonardo, Roberto

    2015-01-01

    The direct conversion of light into work allows the driving of micron-sized motors in a contactless, controllable and continuous way. Light-to-work conversion can involve either direct transfer of optical momentum or indirect opto-thermal effects. Both strategies have been implemented using different coupling mechanisms. However, the resulting efficiencies are always very low, and high power densities, generally obtained by focused laser beams, are required. Here we show that microfabricated gears, sitting on a liquid–air interface, can efficiently convert absorbed light into rotational motion through a thermocapillary effect. We demonstrate rotation rates up to 300 r.p.m. under wide-field illumination with incoherent light. Our analysis shows that thermocapillary propulsion is one of the strongest mechanisms for light actuation at the micron- and nanoscale. PMID:26220862

  19. Effects of green and red light in βL-crystallin and ovalbumin

    PubMed Central

    Espinoza, J. Horacio; Reynaga-Hernández, Elizabeth; Ruiz-García, Jaime; Montero-Morán, Gabriela; Sanchez-Dominguez, Margarita; Mercado-Uribe, Hilda

    2015-01-01

    The effects of visible light on biological systems have been widely studied. In particular, the alterations of blue light on the ocular lens have recently attracted much attention. Here, we present a study about the effects produced by green and red light on two different proteins: βL-crystallin and ovalbumin. Based on differential scanning calorimetry (DSC), circular dichroism (CD), dynamic light scattering (DLS), and fluorescence emission measurements, we found that both wavelengths induce structural changes in these proteins. We also observed that βL-crystallin aggregates. Our work may advance our understanding about conformational and aggregation processes in proteins subjected to visible radiation and the possible relationship with cataracts. While blue light has been considered the only harmful component in the visible espectrum, our findings show the possibility that lower energy components may be also of some concern. PMID:26656181

  20. Effective phase function of light scattered at small angles by polydisperse particulate media

    NASA Astrophysics Data System (ADS)

    Turcu, I.

    2008-06-01

    Particles with typical dimensions higher than the light wavelength and relative refraction indexes close to one, scatter light mainly in the forward direction where the scattered light intensity has a narrow peak. For particulate media accomplishing these requirements the light scattered at small angles in a far-field detecting set-up can be described analytically by an effective phase function (EPF) even in the multiple scattering regime. The EPF model which was built for monodispersed systems has been extended to polydispersed media. The main ingredients consist in the replacement of the single particle phase function and of the optical thickness with their corresponding averaged values. Using a Gamma particle size distribution (PSD) as a testing model, the effect of polydispersity was systematically investigated. The increase of the average radius or/and of the PSD standard deviation leads to the decrease of the angular spreading of the small angle scattered light.

  1. Effects of green and red light in βL-crystallin and ovalbumin

    NASA Astrophysics Data System (ADS)

    Espinoza, J. Horacio; Reynaga-Hernández, Elizabeth; Ruiz-García, Jaime; Montero-Morán, Gabriela; Sanchez-Dominguez, Margarita; Mercado-Uribe, Hilda

    2015-12-01

    The effects of visible light on biological systems have been widely studied. In particular, the alterations of blue light on the ocular lens have recently attracted much attention. Here, we present a study about the effects produced by green and red light on two different proteins: βL-crystallin and ovalbumin. Based on differential scanning calorimetry (DSC), circular dichroism (CD), dynamic light scattering (DLS), and fluorescence emission measurements, we found that both wavelengths induce structural changes in these proteins. We also observed that βL-crystallin aggregates. Our work may advance our understanding about conformational and aggregation processes in proteins subjected to visible radiation and the possible relationship with cataracts. While blue light has been considered the only harmful component in the visible espectrum, our findings show the possibility that lower energy components may be also of some concern.

  2. Effects of polychromatic visible and infrared light on biological liquid media.

    PubMed

    Zilov, V G; Khadartsev, A A; Bitsoev, V D

    2014-08-01

    Experimental study of the effects of polychromatic visible and infrared light on biological fluids was carried out in order to validate the new approaches to phototherapy. Polychromatic light generated by Bioptron device at different modes and frequencies was released through the fiberoptic cable, including the exposure paralleled by CO2 saturation of water and exposure from a device placed 10 cm above the water surface, which ensured maximum light absorption. The effects of irradiation were recorded in 26 and 15 min, while the increase of light absorption by blood plasma in vivo was recorded 1 h after a bath with water pre-exposed to polarized light. Absorption bands corresponding to those for immunomodulatory, anti-inflammatory, and antiviral drugs, were detected. Changes in the spectra of valency oscillations, depending on the oscillation anharmonism values, were detected. PMID:25110085

  3. Effects of native herbs and light on garlic mustard (Alliaria petiolata) invasion

    USGS Publications Warehouse

    Phillips-Mao, Laura; Larson, Diane L.; Jordan, Nicholas R.

    2014-01-01

    The degree to which invasive species drive or respond to environmental change has important implications for conservation and invasion management. Often characterized as a driver of change in North American woodlands, the invasive herb garlic mustard may instead respond to declines in native plant cover and diversity. We tested effects of native herb cover, richness, and light availability on garlic mustard invasion in a Minnesota oak woodland. We planted 50 garlic mustard seeds into plots previously planted with 0 to 10 native herb species. We measured garlic mustard seedling establishment, survival to rosette and adult stages, and average (per plant) and total (per plot) biomass and silique production. With the use of structural equation models, we analyzed direct, indirect, and net effects of native cover, richness, and light on successive garlic mustard life stages. Native plant cover had a significant negative effect on all life stages. Species richness had a significant positive effect on native cover, resulting in indirect negative effects on all garlic mustard stages, and net negative effects on adult numbers, total biomass, and silique production. Light had a strong negative effect on garlic mustard seedling establishment and a positive effect on native herb cover, resulting in significant negative net effects on garlic mustard rosette and adult numbers. However, light's net effect on total garlic mustard biomass and silique production was positive; reproductive output was high even in low-light/high-cover conditions. Combined effects of cover, richness, and light suggest that native herbs provide biotic resistance to invasion by responding to increased light availability and suppressing garlic mustard responses, although this resistance may be overwhelmed by high propagule pressure. Garlic mustard invasion may occur, in part, in response to native plant decline. Restoring native herbs and controlling garlic mustard seed production may effectively reduce

  4. Seed-mass effects in four Mediterranean Quercus species (Fagaceae) growing in contrasting light environments.

    PubMed

    Quero, José Luis; Villar, Rafael; Marañón, Teodoro; Zamora, Regino; Poorter, Lourens

    2007-11-01

    Three hypotheses have been proposed to explain the functional relationship between seed mass and seedling performance: the reserve effect (larger seeds retain a larger proportion of reserves after germinating), the metabolic effect (seedlings from larger seeds have slower relative growth rates), and the seedling-size effect (larger seeds produce larger seedlings). We tested these hypotheses by growing four Mediterranean Quercus species under different light conditions (3, 27, and 100% of available radiation). We found evidence for two of the three hypotheses, but none of the four species complied with all three hypotheses at the same time. The reserve effect was not found in any species, the metabolic effect was found in three species (Q. ilex, Q. pyrenaica, and Q. suber), and the seedling-size effect in all species. Light availability significantly affected the relationships between seed size and seedling traits. For Q. ilex and Q. canariensis, a seedling-size effect was found under all three light conditions, but only under the lowest light (3%) for Q. suber and Q. pyrenaica. In all species, the correlation between seed mass and seedling mass increased with a decrease in light, suggesting that seedlings growing in low light depend more upon their seed reserves. A causal model integrates the three hypotheses, suggesting that larger seeds generally produced larger seedlings. PMID:21636374

  5. Chemical mixtures and environmental effects: a pilot study to assess ecological exposure and effects in streams

    USGS Publications Warehouse

    Buxton, Herbert T.; Reilly, Timothy J.; Kuivila, Kathryn M.; Kolpin, Dana W.; Bradley, Paul M.; Villeneuve, Daniel L.; Mills, Marc A.

    2015-01-01

    Assessment and management of the risks of exposure to complex chemical mixtures in streams are priorities for human and environmental health organizations around the world. The current lack of information on the composition and variability of environmental mixtures and a limited understanding of their combined effects are fundamental obstacles to timely identification and prevention of adverse human and ecological effects of exposure. This report describes the design of a field-based study of the composition and biological activity of chemical mixtures in U.S. stream waters affected by a wide range of human activities and contaminant sources. The study is a collaborative effort by the U.S. Geological Survey and the U.S. Environmental Protection Agency. Scientists sampled 38 streams spanning 24 States and Puerto Rico. Thirty-four of the sites were located in watersheds impacted by multiple contaminant sources, including industrial and municipal wastewater discharges, crop and animal agricultural runoff, urban runoff, and other point and nonpoint contaminant sources. The remaining four sites were minimally development reference watersheds. All samples underwent comprehensive chemical and biological characterization, including sensitive and specific direct analysis for over 700 dissolved organic and inorganic chemicals and field parameters, identification of unknown contaminants (environmental diagnostics), and a variety of bioassays to evaluate biological activity and toxicity.

  6. Chemical Magnetoreception: Bird Cryptochrome 1a Is Excited by Blue Light and Forms Long-Lived Radical-Pairs

    PubMed Central

    Liedvogel, Miriam; Maeda, Kiminori; Henbest, Kevin; Schleicher, Erik; Simon, Thomas; Timmel, Christiane R.; Hore, P. J.; Mouritsen, Henrik

    2007-01-01

    Cryptochromes (Cry) have been suggested to form the basis of light-dependent magnetic compass orientation in birds. However, to function as magnetic compass sensors, the cryptochromes of migratory birds must possess a number of key biophysical characteristics. Most importantly, absorption of blue light must produce radical pairs with lifetimes longer than about a microsecond. Cryptochrome 1a (gwCry1a) and the photolyase-homology-region of Cry1 (gwCry1-PHR) from the migratory garden warbler were recombinantly expressed and purified from a baculovirus/Sf9 cell expression system. Transient absorption measurements show that these flavoproteins are indeed excited by light in the blue spectral range leading to the formation of radicals with millisecond lifetimes. These biophysical characteristics suggest that gwCry1a is ideally suited as a primary light-mediated, radical-pair-based magnetic compass receptor. PMID:17971869

  7. Effects of various runway lighting parameters upon the relation between runway visual range and visual range of centerline and edge lights in fog

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1973-01-01

    Thirty six students and 54 commercial airline pilots were tested in the fog chamber to determine the effect of runway edge and centerline light intensity and spacing, fog density, ambient luminance level, and lateral and vertical offset distance of the subject from the runway's centerline upon horizontal visual range. These data were obtained to evaluate the adequacy of a balanced lighting system to provide maximum visual range in fog viewing both centerline and runway edge lights. The daytime system was compared against two other candidate lighting systems; the nighttime system was compared against other candidate lighting systems. The second objective was to determine if visual range is affected by lights between the subject and the farthestmost light visible through the fog. The third objective was to determine if college student subjects differ from commercial airline pilots in their horizontal visual range through fog. Two studies were conducted.

  8. Genotoxic and developmental effects in sea urchins are sensitive indicators of effects of genotoxic chemicals

    SciTech Connect

    Anderson, S.L. . Energy and Environment Division); Hose, J.E. . Dept. of Biology); Knezovich, J.P. . Health and Ecological Assessment Division)

    1994-07-01

    Purple sea urchin (Strongylocentrotus purpuratus) gametes and embryos were exposed to three known mutagenic chemicals (phenol, benzidine,and pentachlorophenol) over concentration ranges bracketing the effect levels for fertilization success. Normal development and cytogenetic effects (anaphase aberrations) were assessed after the cultures were allowed to develop for 48 h. Using radiolabeled chemicals, the authors also characterized concentrations in the test water as well as doses in the embryos following 2- and 48-h exposures. The authors observed dose responses for all chemicals and all responses, except for phenol, which showed no significant effect on development. Fertilization success was never the most sensitive end point. anaphase aberrations were the most sensitive response for phenol, with an LOEC of 2.5 mg/L exposure concentration. Anaphase aberrations and development were equivalent in sensitivity for benzidine within the tested dose range, and an LOEC of <0.1 mg/L was observed. Development was the most sensitive reasons for pentachlorophenol (LOEC 1 mg/L). the LOEC values for this study were generally lower than comparable data for aquatic life or human health protection. The authors conclude that genotoxicity and development evaluations should be included in environmental management applications and that tests developed primarily for human health protection do not reliably predict the effects of toxic substances on aquatic life.

  9. The study of light waveguide effects on ZnO nanorod arrays

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Un; Gang, Myeng-Gil; Kim, Jin-A.; Moon, Jong-Ha; Kim, Doo-Gun; Kim, Seon-Hoon; Ki, Hyun-Chul; Choi, Ju-hyeon; Kim, Jin-Hyeok

    2016-03-01

    Two different types of ZnO nanorods (hexagonal pyramid-shaped nanorod and hexagonal prism-shaped nanorod) were integrated on light emitting diodes (LEDs) for the investigation of light waveguide effects, which were evaluated using electroluminescence (EL) and current-voltage ( I- V) characteristics. EL intensity in LEDs with hexagonal prism-shaped ZnO nanorod arrays were improved by 18% while EL intensity in LEDs with hexagonal pyramid-shaped ZnO nanorods were reduced by 25% compared to bare LEDs. 3D-finite dimension time domain (3D-FDTD) programs were used to simulate the light waveguide effect on the two different shapes of ZnO nanorods. In addition, photonic crystals (PCs) effects in ZnO nanorod arrays were simulated to verify the light waveguide effect. It was found that light in a hexagonal prism-shaped ZnO nanorod propagated from the bottom to the top end. However, the light in a hexagonal pyramid-shaped ZnO nanorod was dissipated on the lateral face. The light extraction efficiency in ZnO nanorod arrays was dominated by the top end shape and planar density of ZnO nanorods. [Figure not available: see fulltext.

  10. Pollination by nocturnal Lepidoptera, and the effects of light pollution: a review

    PubMed Central

    MacGregor, Callum J; Pocock, Michael J O; Fox, Richard; Evans, Darren M

    2015-01-01

    1. Moths (Lepidoptera) are the major nocturnal pollinators of flowers. However, their importance and contribution to the provision of pollination ecosystem services may have been under-appreciated. Evidence was identified that moths are important pollinators of a diverse range of plant species in diverse ecosystems across the world. 2. Moth populations are known to be undergoing significant declines in several European countries. Among the potential drivers of this decline is increasing light pollution. The known and possible effects of artificial night lighting upon moths were reviewed, and suggest how artificial night lighting might in turn affect the provision of pollination by moths. The need for studies of the effects of artificial night lighting upon whole communities of moths was highlighted. 3. An ecological network approach is one valuable method to consider the effects of artificial night lighting upon the provision of pollination by moths, as it provides useful insights into ecosystem functioning and stability, and may help elucidate the indirect effects of artificial light upon communities of moths and the plants they pollinate. 4. It was concluded that nocturnal pollination is an ecosystem process that may potentially be disrupted by increasing light pollution, although the nature of this disruption remains to be tested. PMID:25914438

  11. Regulation of lipid peroxidation in the retina under the effect of bright light.

    PubMed

    Dzhafarov, A I; Kasimov, E M; Mamedov, Sh Y

    2011-04-01

    Changes in LPO intensity under the effect of exposure to bright light and the possibility of their correction with antioxidants were studied on rabbits with diabetic retinopathy. It was found that enhanced LPO caused by exposure to bright light in rabbits with diabetic retinopathy can be corrected with antioxidants. Phenosan potassium salt, α-tocopherol, and oxypyridine were more effective than SOD and taurine in preventing MDA accumulation. A complex of natural and synthetic antioxidants was most efficient in correcting LPO under conditions of exposure to bright light. PMID:22235421

  12. Lighting effects rendering in three-dimensional computer-generated holographic display

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Cao, Liangcai; Jin, Guofan

    2016-07-01

    We present a technique for generating three-dimensional (3-D) computer-generated holograms (CGHs) with realistic lighting effects based on a phase-only spatial light modulator (SLM). Phong reflection model is employed in the calculation of reflectance distribution for CGH synthesizing. Directional point-based algorithm produces realistic lighting effects of the 3-D scenes in processing the ambient, diffuse and specular reflections. A phase-only SLM is used to perform the optical experiments, and the results show that the proposed technique can perform quality reconstructions of the 3-D scenes with high optical efficiency and efficient utilization of the system space-bandwidth product.

  13. Aerosol optical thickness from Brewer spectrophotometers and an investigation into the stray-light effect.

    PubMed

    Silva, Abel A; Kirchhoff, Volker W J H

    2004-04-20

    The Langley method has been applied to the measurements of direct solar radiation made by Brewer spectrophotometers to obtain the aerosol optical thickness (AOT) of the atmosphere in the ultraviolet-B range. In several cases the AOT increased with wavelength, which raises suspicion about the stray-light effect. To investigate the quality of the AOT measurements and the possibility of stray light, we conducted a campaign by using single- and double-monochromator Brewers. The campaign's results have shown that both Brewers' AOT values are in good agreement and that stray light is not an important effect for AOT at wavelengths above 306 nm. PMID:15119618

  14. Chemical potential effects on neutrino diffusion in supernovae

    NASA Technical Reports Server (NTRS)

    Mazurek, T. J.

    1975-01-01

    The validity of imposing a zero chemical potential for neutrinos in hydrodynamic calculations of collapsing supernovae is investigated in the diffusion approximation of neutrino transport. A coupled system of equations is solved for neutrino and energy diffusion fluxes as well as lepton diffusion in a collapsing supernovae ambient medium, and the results indicate a substantial growth in the neutrino chemical potential for densities greater than 10 to the 12th power gm/cu cm. The rate of energy transport is shown to be significantly affected by increases in Fermi integrals and chemical-potential gradients accompanied by decreases in temperature, and the extent of neutrino particle/antiparticle reactions is found also to affect energy diffusion rates. It is concluded that the photon-like behavior usually assumed for neutrinos may be incorrect and that an extension of the Sn transport approximation to include lepton characteristics is necessary for a definitive answer to the question of neutrino transport in supernovae.

  15. Magma zonation - Effects of chemical buoyancy and diffusion

    NASA Technical Reports Server (NTRS)

    Spera, Frank J.; Oldenburg, Curtis M.; Yuen, David A.

    1989-01-01

    Numerical simulations and scale analysis are used to assess the viability of the marginal box-filling mechanism for producing compositional zonation in magma bodies. Scale analysis and two-dimensional numerical experiments both show that box-filling occurs provided a critical ratio of compositional-to-thermal buoyancy is exceeded. This critical ratio depends on the ratio of thermal-to-chemical diffusivity; application of this result to magma bodies suggests that box-filling may occur for components with relatively high-chemical diffusivities such as water. However, box-filling will not produce significant zonation for components with small chemical diffusivities, such as silica, unless diffusive coupling increases silica diffusivity.

  16. Investigation and modeling of the effects of light spectrum and incident angle on the growth of Chlorella vulgaris in photobioreactors.

    PubMed

    Souliès, Antoine; Legrand, Jack; Marec, Hélène; Pruvost, Jérémy; Castelain, Cathy; Burghelea, Teodor; Cornet, Jean-François

    2016-03-01

    An in-depth investigation of how various illumination conditions influence microalgal growth in photobioreactors (PBR) has been presented. Effects of both the light emission spectrum (white and red) and the light incident angle (0° and 60°) on the PBR surface were investigated. The experiments were conducted in two fully controlled lab-scale PBRs, a torus PBR and a thin flat-panel PBR for high cell density culture. The results obtained in the torus PBR were used to build the kinetic growth model of Chlorella vulgaris taken as a model species. The PBR model was then applied to the thin flat-panel PBR, which was run with various illumination conditions. Its detailed representation of local rate of photon absorption under various conditions (spectral calculation of light attenuation, incident angle influence) enabled the model to take into account all the tested conditions with no further adjustment. This allowed a detailed investigation of the coupling between radiation field and photosynthetic growth. Effects of all the radiation conditions together with pigment acclimation, which was found to be relevant, were investigated in depth. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:247-261, 2016. PMID:26871260

  17. Effects of Diffuse Light on Radiation Use Efficiency of Two Anthurium Cultivars Depend on the Response of Stomatal Conductance to Dynamic Light Intensity

    PubMed Central

    Li, Tao; Kromdijk, Johannes; Heuvelink, Ep; van Noort, F. R.; Kaiser, Elias; Marcelis, Leo F. M.

    2016-01-01

    The stimulating effect of diffuse light on radiation use efficiency (RUE) of crops is often explained by the more homogeneous spatial light distribution, while rarely considering differences in temporal light distribution at leaf level. This study investigated whether diffuse light effects on crop RUE can be explained by dynamic responses of leaf photosynthesis to temporal changes of photosynthetic photon flux density (PPFD). Two Anthurium andreanum cultivars (‘Pink Champion’ and ‘Royal Champion’) were grown in two glasshouses covered by clear (control) and diffuse glass, with similar light transmission. On clear days, diffusing the light resulted in less temporal fluctuations of PPFD. Stomatal conductance (gs) varied strongly in response to transient PPFD in ‘Royal Champion,’ whereas it remained relatively constant in ‘Pink Champion.’ Instantaneous net leaf photosynthesis (Pn) in both cultivars approached steady state Pn in diffuse light treatment. In control treatment this only occurred in ‘Pink Champion.’ These cultivar differences were reflected by a higher RUE (8%) in ‘Royal Champion’ in diffuse light treatment compared with control, whereas no effect on RUE was observed in ‘Pink Champion.’ We conclude that the stimulating effect of diffuse light on RUE depends on the stomatal response to temporal PPFD fluctuations, which response is cultivar dependent. PMID:26870071

  18. Effects of Diffuse Light on Radiation Use Efficiency of Two Anthurium Cultivars Depend on the Response of Stomatal Conductance to Dynamic Light Intensity.

    PubMed

    Li, Tao; Kromdijk, Johannes; Heuvelink, Ep; van Noort, F R; Kaiser, Elias; Marcelis, Leo F M

    2016-01-01

    The stimulating effect of diffuse light on radiation use efficiency (RUE) of crops is often explained by the more homogeneous spatial light distribution, while rarely considering differences in temporal light distribution at leaf level. This study investigated whether diffuse light effects on crop RUE can be explained by dynamic responses of leaf photosynthesis to temporal changes of photosynthetic photon flux density (PPFD). Two Anthurium andreanum cultivars ('Pink Champion' and 'Royal Champion') were grown in two glasshouses covered by clear (control) and diffuse glass, with similar light transmission. On clear days, diffusing the light resulted in less temporal fluctuations of PPFD. Stomatal conductance (g s) varied strongly in response to transient PPFD in 'Royal Champion,' whereas it remained relatively constant in 'Pink Champion.' Instantaneous net leaf photosynthesis (P n) in both cultivars approached steady state P n in diffuse light treatment. In control treatment this only occurred in 'Pink Champion.' These cultivar differences were reflected by a higher RUE (8%) in 'Royal Champion' in diffuse light treatment compared with control, whereas no effect on RUE was observed in 'Pink Champion.' We conclude that the stimulating effect of diffuse light on RUE depends on the stomatal response to temporal PPFD fluctuations, which response is cultivar dependent. PMID:26870071

  19. Effect of different exposed lights on quercetin and quercetin glucoside content in onion (Allium cepa L.)

    PubMed Central

    Ko, Eun Young; Nile, Shivraj Hariram; Sharma, Kavita; Li, Guan Hao; Park, Se Won

    2014-01-01

    Quercetin and quercetin glucosides are the major flavonols present in onion (Allium cepa L.) and are predominantly present as quercetin, quercetin-3,4′-diglucoside and quercetin-4′-glucoside. Effect of different light wavelengths on onion after harvest and storage, with fluorescent, blue, red and ultra violet light influenced the quercetin and quercetin glucosides profile. In a peeled onion, all the light treatments elevated quercetin content in bulb. Among them, particularly fluorescent light effect was more eminent which stimulates the maximum synthesis of quercetin in onion. In case of whole onion bulb, skin and pulp showed different responses to light treatment, respectively. The pulp had the highest quercetin glucosides under blue light, whereas the lowest under fluorescent light. Onion skin showed nearly opposite pattern as compared to the pulp. In particular, light treatment proved to be a better way to increase the level of quercetin content in onions which might be utilized for industrial production of bioactive compounds from onion and onion waste products. PMID:26150744

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

    PubMed

    Lafuente, María T; Alférez, Fernando

    2015-11-01

    Studies on the antimicrobial properties of light have considerably increased due in part to the development of resistance to actual control methods. This study investigates the potential of light-emitting diodes (LED) blue light for controlling Penicillium digitatum and Penicillium italicum. These fungi are the most devastating postharvest pathogens of citrus fruit and cause important losses due to contaminations and the development of resistant strains against fungicides. The effect of different periods and quantum fluxes, delaying light application on the growth and morphology of P. digitatum strains resistant and sensitive to fungicides, and P. italicum cultured at 20°C was examined. Results showed that blue light controls the growth of all strains and that its efficacy increases with the quantum flux. Spore germination was always avoided by exposing the cultures to high quantum flux (700 μmol m(-2) s(-1) ) for 18 h. Continuous light had an important impact on the fungus morphology and a fungicidal effect when applied at a lower quantum flux (120 μmol m(-2) s(-1) ) to a growing fungus. Sensitivity to light increased with mycelium age. Results show that blue light may be a tool for P. digitatum and P. italicum infection prevention during handling of citrus fruits. PMID:26288067

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  2. Effect of different exposed lights on quercetin and quercetin glucoside content in onion (Allium cepa L.).

    PubMed

    Ko, Eun Young; Nile, Shivraj Hariram; Sharma, Kavita; Li, Guan Hao; Park, Se Won

    2015-07-01

    Quercetin and quercetin glucosides are the major flavonols present in onion (Allium cepa L.) and are predominantly present as quercetin, quercetin-3,4'-diglucoside and quercetin-4'-glucoside. Effect of different light wavelengths on onion after harvest and storage, with fluorescent, blue, red and ultra violet light influenced the quercetin and quercetin glucosides profile. In a peeled onion, all the light treatments elevated quercetin content in bulb. Among them, particularly fluorescent light effect was more eminent which stimulates the maximum synthesis of quercetin in onion. In case of whole onion bulb, skin and pulp showed different responses to light treatment, respectively. The pulp had the highest quercetin glucosides under blue light, whereas the lowest under fluorescent light. Onion skin showed nearly opposite pattern as compared to the pulp. In particular, light treatment proved to be a better way to increase the level of quercetin content in onions which might be utilized for industrial production of bioactive compounds from onion and onion waste products. PMID:26150744

  3. Effect of ambient humidity on light transmittance through skin phantoms during cryogen spray cooling.

    PubMed

    Ramirez-San-Juan, Julio C; Choi, Bernard; Franco, Walfre; Nelson, J Stuart; Aguilar, Guillermo

    2006-01-01

    Cryogen spray cooling (CSC) is a technique employed to reduce the risk of epidermal damage during dermatologic laser surgery. However, while CSC protects the epidermis from non-specific thermal damage, it might reduce the effective fluence reaching the target chromophore due to scattering of light by the spray droplets and subsequent water condensation/freezing on the skin surface. The objective of this work was to study the effect of ambient humidity (omega) on light transmittance during CSC. An integrating sphere was employed to measure the dynamics of light transmittance through a deformable agar phantom during CSC. The study included two representative CSC spurt patterns studied using four omega: 57, 40, 20 and 12%. Results show that during CSC, as omega increased, light transmittance decreased. For the highest humidity level (57%) studied, light transmittance reached a minimum of 55% approximately 30 ms after spurt termination. In a controlled environment with omega = 12%, light transmittance reached a minimum of 87% approximately 30 ms after spurt termination. The reduced light transmittance immediately after spurt termination was most likely because of scattering of light caused by condensation of water vapour due to aggressive cooling of ambient air in the wake of the cryogen spurt. PMID:16357434

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

    PubMed

    Cavazzoni, James; Volk, Tyler; Tubiello, Francesco; Monje, Oscar

    2002-01-01

    A layered canopy model was used to analyze the effects of diffuse light on canopy gross photosynthesis in controlled environment plant growth chambers, where, in contrast to the field, highly diffuse light can occur at high irradiance. The model suggests that high diffuse light fractions (approximately 0.7) and irradiance (1400 micromoles m-2 s-1) may enhance crop life-cycle canopy gross photosynthesis for hydroponic wheat by about 20% compared to direct light at the same irradiance. Our simulations suggest that high accuracy is not needed in specifying diffuse light fractions in chambers between approximately 0.7 and 1, because simulated photosynthesis for closed canopies plateau in this range. We also examined the effect of leaf angle distribution on canopy photosynthesis under growth chamber conditions, as these distributions determine canopy extinction coefficients for direct and diffuse light. We show that the spherical leaf angle distribution is not suitable for modeling photosynthesis of planophile canopies (e.g., soybean and peanut) in growth chambers. Also, the absorption of the light reflected from the surface below the canopy should generally be included in model simulations, as the corresponding albedo values in the photosynthetically active range may be quite high in growth chambers (e.g., approximately 0.5). In addition to the modeling implications, our results suggest that diffuse light conditions should be considered when drawing conclusions from experiments in controlled environments. PMID:12882223

  5. Theory of light quenching: effects of fluorescence polarization, intensity, and anisotropy decays.

    PubMed Central

    Kuśba, J; Bogdanov, V; Gryczynski, I; Lakowicz, J R

    1994-01-01

    Experimental studies have recently demonstrated that fluorescence emission can be quenched by laser light pulses from modern high repetition rate lasers, a phenomenon we call "light quenching." We now describe the theory of light quenching and some of its effects on the steady-state and time-resolved intensity and anisotropy decays of fluorophores. Light quenching can decrease or increase the steady-state or time-zero anisotropy. Remarkably, the light quenching can break the usual z axis symmetry of the excited-state population, and the emission polarization can range from -1 to +1 under selected conditions. The measured anisotropy (or polarization) depends upon whether the observation axis is parallel or perpendicular to the propagation direction of the light quenching beam. The effects of light quenching are different for a single pulse, which results in both excitation and quenching, as compared with a time-delayed quenching pulse. Time-delayed light quenching pulses can result in step-like changes in the time-dependent intensity or anisotropy and are predicted to cause oscillations in the frequency-domain intensity and anisotropy decays. The increasing availability of pulsed laser sources offers the opportunity for a new class of two-pulse or multiple-pulse experiments where the sample is prepared by an excitation pulse, the excited state population is modified by the quenching pulse(s), followed by time- or frequency-domain measurements of the resulting emission. PMID:7858140

  6. Ultra low fluence rate photodynamic therapy: simulation of light emitted by the Cerenkov effect

    NASA Astrophysics Data System (ADS)

    Gonzales, Jonathan; Wang, Fred; Zamora, Genesis; Trinidad, Anthony; Marcu, Laura; Cherry, Simon; Hirschberg, Henry

    2014-03-01

    PDT has been shown to be most effective at low fluence rates. Many radionuclides used for both diagnostic and therapeutic purposes produce measurable amounts of visible radiation when they decay via the Cerenkov effect which occurs when a charged particle travels faster in a dielectric medium than the speed of light in that medium. Cerenkov radiation from radiopharmaceuticals could serve as a source of extended duration, low level "internal" light, to mediate PDT, with the ultimate goals of overcoming some its current limitations. Using laser light, we are exploring the effects of fluence rates that could be generated by Cerenkov radiation on PDT efficacy. ALA or TPPS2a mediated PDT of rat gliomas monolayers or multicell spheroids ( F98, C6) was performed with 410 nm laser light exposure over an extended period of 24-96hrs. Photosensitizers were delivered either as a bolus or continuously with light exposure. At fluence rate of 20μW/cm2 effective PDT was obtained as measured by decrease in cell viability or inhibition of spheroid growth. PDT is effective at ultra low fluence rates if given over long time periods. No lower threshold has been ascertained. Since the half-life of 90Y, a radionuclide with a high Cherenkov yield is 64 hrs it is a good candidate to supply sufficient light activation for PDT. The combination of radionuclide and photodynamic therapies could improve the effectiveness of cancer treatment by exploiting synergies between these two modalities.

  7. Non-equilibrium effects in high temperature chemical reactions

    NASA Technical Reports Server (NTRS)

    Johnson, Richard E.

    1987-01-01

    Reaction rate data were collected for chemical reactions occurring at high temperatures during reentry of space vehicles. The principle of detailed balancing is used in modeling kinetics of chemical reactions at high temperatures. Although this principle does not hold for certain transient or incubation times in the initial phase of the reaction, it does seem to be valid for the rates of internal energy transitions that occur within molecules and atoms. That is, for every rate of transition within the internal energy states of atoms or molecules, there is an inverse rate that is related through an equilibrium expression involving the energy difference of the transition.

  8. Effects of HZE irradiation on chemical neurotransmission in rodent hippocampus

    NASA Astrophysics Data System (ADS)

    Machida, Mayumi

    Space radiation represents a significant risk to the CNS (central nervous system) during space missions. Most harmful are the HZE (high mass, highly charged (Z), high energy) particles, e.g. 56Fe, which possess high ionizing ability, dense energy deposition pattern, and high penetrance. Accumulating evidence suggests that radiation has significant impact on cognitive functions. In ground-base experiments, HZE radiation induces pronounced deficits in hippocampus dependent learning and memory in rodents. However, the mechanisms underlying these impairments are mostly unknown. Exposure to HZE radiation elevates the level of oxidation, resulting in cell loss, tissue damage and functional deficits through direct ionization and generation of reactive oxygen species (ROS). When hippocampal slices were exposed to ROS, neuronal excitability was reduced. My preliminary results showed enhanced radio-vulnerability of the hippocampus and reduction in basal and depolarization-evoked [3H]-norepinephrine release after HZE exposure. These results raised the possibility that HZE radiation deteriorates cognitive function through radiation-induced impairments in hippocampal chemical neurotransmission, the hypothesis of this dissertation. In Aim 1 I have focused on the effects of HZE radiation on release of major neurotransmitter systems in the hippocampus. I have further extended my research on the levels of receptors of these systems in Aim 2. In Aim 3, I have studied the level of oxidation in membranes of my samples. My research reveals that HZE radiation significantly reduces hyperosmotic sucrose evoked [3H]-glutamate and [14C]-GABA release both three and six months post irradiation. The same radiation regimen also significantly enhances oxidative stress as indicated by increased levels of lipid peroxidation in the hippocampus, suggesting that increased levels of lipid peroxidation may play a role in reduction of neurotransmitter release. HZE radiation also significantly reduces

  9. Synergistic and antagonistic effects on genotoxicity of chemicals commonly found in hazardous waste sites

    SciTech Connect

    Ma, T.H.; Sandhu, S.S.; Peng, Y.; Chen, T.D.; Kim, T.W.

    1992-01-01

    Synergistic and antagonistic effects on genotoxicity of mixtures of four chemicals; i.e., lead tetraacetate (LTA), arsenic trioxide (ATO), dieldrin (DED), and tetrachloroethylene (TCE), were evaluated by the Tradescantia-micronucleus (Trad-MCN) assay. The chemicals were mixed in ratios of 1:1, 1:2 and 2:1 for mixtures of two chemicals and 1:1:1 each for three chemicals. The concentration of stock solution of these chemicals was around the minimum effective dose (MED) or below the MED for these chemicals as reported by Sandhu et al. (1989). Treatments were applied to plant cuttings by hydroponic uptake of the mixed solutions through the stems of the plant for 30 h followed by fixation of the flower buds in aceto-alcohol (1:3 ratio) without a recovery period. Microslides were prepared for scoring MCN frequencies. Results of two series of repeated experiments indicated that all mixtures of LTA/ATO exhibited antagonistic effects. On the other hand, all mixtures of TCE and DED exhibited synergistic effect. These data indicate that for evaluating biological hazards at chemical waste sites, it is prudent to evaluate the genotoxicity of complex chemical mixtures as these exist in nature because the biological effects based on evaluating individual chemicals may not be true predictors of the interactive effects of the pollutants.

  10. Effects of light sources on growth and carotenoid content of photosynthetic bacteria Rhodopseudomonas palustris.

    PubMed

    Kuo, Fu-Shiu; Chien, Yew-Hu; Chen, Chang-Jiang

    2012-06-01

    This study investigated the effects of eight light sources on photosynthetic bacteria (Rhodopseudomonas palustris) growth and carotenoid content (CD), cultured for 144 h. Light sources were incandescent lamp (IL), halogen lamp (HL), fluorescence lamp (FL), and light-emitting diodes (LEDs) of white (LW), yellow (LY), red (LR), blue (LB), and green (LG). Dark condition served as the control. Under around 2000 lux, light sources ranked greatest to least bacterial growth effect were (LB=IL) > FL > LW ≥ HL ≥ LR ≥ (LG=LY=DK). Ranking effect on CD content was LB > IL ≥ LY ≥ (HL=LR=LG) ≥ LW ≥ DK ≥ FL. Energy efficiency for bacterial growth was LB > LW > LY > IL > LG > HL > FL > LR. CD productivity ranking was LB > LY > LW > LG > IL > HL > LR > FL. Results revealed that LB saved 75% energy and increased CD productivity by 348% compared with IL. PMID:22330604

  11. Aharonov-Bohm effect induced by circularly polarized light

    NASA Astrophysics Data System (ADS)

    Sigurdsson, H.; Kibis, O. V.; Shelykh, I. A.

    2015-11-01

    We demonstrated theoretically that the strong electron interaction with circularly polarized photons in ring-like nanostructures changes the phase of electron wave. This optically-induced effect is caused by the breaking of time-reversal symmetry and is similar to the Aharonov-Bohm effect. As a consequence of this phenomenon, the conductance of mesoscopic rings irradiated by a circularly polarized electromagnetic wave behaves as an oscillating function of the intensity and frequency of the wave.

  12. (77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects.

    PubMed

    Struppe, Jochem; Zhang, Yong; Rozovsky, Sharon

    2015-03-01

    The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest

  13. 77Se Chemical Shift Tensor of L-selenocystine: Experimental NMR Measurements and Quantum Chemical Investigations of Structural Effects

    PubMed Central

    Struppe, Jochem; Zhang, Yong; Rozovsky, Sharon

    2015-01-01

    The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine’s specialized biological roles, it is of interest to examine their 77Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state 77Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information of selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on 77Se L-selenocystine’s chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10–20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of −180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. −90°, the energy costs to alter the dihedral angle in the range from −120° to −60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. 77Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272±30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3–9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results

  14. Variable sensitivity of organic light-emitting diodes to operation-induced chemical degradation: Nature of the antagonistic relationship between lifetime and efficiency

    NASA Astrophysics Data System (ADS)

    Kondakov, Denis Y.; Young, Ralph H.

    2010-10-01

    The efficiency of any organic light-emitting diode (OLED) decreases with prolonged operation. In fluorescent OLEDs containing the standard hole-transporting material NPB [N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine], prolonged operation also results in chemical degradation of the NPB. Qualitatively and quantitatively, the extent and location of chemical changes are consistent with the hypothesis that chemical degradation of NPB is largely responsible for the loss of device efficiency and that the degradation is initiated by bond-breaking in excited-state NPB. Blue fluorescent OLEDs with low operating voltages and high luminance efficiencies tend to lose efficiency much faster than OLEDs with higher operating voltages and lower efficiencies. Even so, the two types exhibit approximately the same kind and degree of chemical degradation after operation for equal times at equal current densities. In the low-voltage OLEDs, the electric field in the light-emitting layer is weaker, and the concentration of NPB radical-cations near the emission zone is smaller than in the higher-voltage devices. Apparently for this reason, degradation products impair the luminescent efficiency more severely in the low-voltage OLEDs. Such differing sensitivity of low-voltage and high-voltage OLEDs to the same amount of chemical degradation is further demonstrated by experiments with OLEDs that have been doped intentionally with a contaminant modeling a degradation product at realistic concentrations. It is also supported by a substantial recovery of efficiency after a conversion of a degraded low-voltage device into a high-voltage device by replacement of the cathode and electron-injecting interface.

  15. NMR chemical shifts in amino acids: Effects of environments, electric field, and amine group rotation

    SciTech Connect

    Yoon, Young-Gui; Pfrommer, Bernd G.; Louie, Steven G.; Canning, Andrew

    2002-03-03

    The authors present calculations of NMR chemical shifts in crystalline phases of some representative amino acids such as glycine, alanine, and alanyl-alanine. To get an insight on how different environments affect the chemical shifts, they study the transition from the crystalline phase to completely isolated molecules of glycine. In the crystalline limit, the shifts are dominated by intermolecular hydrogen-bonds. In the molecular limit, however, dipole electric field effects dominate the behavior of the chemical shifts. They show that it is necessary to average the chemical shifts in glycine over geometries. Tensor components are analyzed to get the angle dependent proton chemical shifts, which is a more refined characterization method.

  16. Effect Size Estimates in Chemical Aversion Treatments of Alcoholism.

    ERIC Educational Resources Information Center

    Thurber, Steven

    1985-01-01

    Reports that aggregate studies on alcohol aversion therapy tended to support a moderate level of treatment impact that may have noteworthy practical import. Emetics appeared to generate fairly consistent findings; a paralysis-inducing chemical may produce variable results. (Author/NRB)

  17. Chemical Effects in Food Stored at Room Temperature.

    ERIC Educational Resources Information Center

    Karel, Marcus

    1984-01-01

    Nonenzymatic browning and lipid oxidation, two important chemical deteriorative mechanisms, are discussed. The first is the major cause of darkening of concentrated and dehydrated stored foods and is also the cause of various cooked and stale flavors in food. The second is the major cause of rancidity in foods. (JN)

  18. Effects of chemical amendments to swine manure on runoff quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land-applied swine manure can be an environmental concern when runoff losses of manure constituents occur. The use of chemical amendments to mitigate these losses has been investigated for poultry litter, but materials such as swine manure have received less attention in this context, particularly ...

  19. Microsieving in primary treatment: effect of chemical dosing.

    PubMed

    Väänänen, J; Cimbritz, M; la Cour Jansen, J

    2016-01-01

    Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20-65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al(3+)/L or 30 mg Fe(3+)/L. When comparing sieve pore sizes of 30-40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95-97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter. PMID:27438249

  20. EFFECT OF CHEMICAL CARRIERS ON AVIAN LC(50) TOXICITY TESTS

    EPA Science Inventory

    The subacute dietary (LC50) toxicity of a pesticide as prescribed by the Federal Insecticide Fungicide and Rodenticide Act and of toxic substances as defined by the Toxic Substances Control Act is a routine data point for many chemicals. The methods under which the LC50 data are ...