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Sample records for high light conditions

  1. COP1/SPA ubiquitin ligase complexes repress anthocyanin accumulation under low light and high light conditions.

    PubMed

    Maier, Alexander; Hoecker, Ute

    2015-01-01

    In Arabidopsis and many other plant species, anthocyanin pigments accumulate only after light exposure and not in darkness. Excess light of very high fluence rates leads to a further, very strong increase in anthocyanin levels. How excess light is sensed is not well understood. Here, we show that mutations in the key repressor of light signaling, the COP1/SPA complex, cause a strong hyperaccumulation of anthocyanins not only under normal light but also under excess, high light conditions. Hence, normal light signaling via COP1/SPA is required to prevent hyperaccumulation of anthocyanins under these high light conditions. However, since cop1 and spa mutants show a similar high-light responsiveness of anthocyanin accumulation as the wild type it remains to be resolved whether COP1/SPA is directly involved in the high-light response itself.

  2. Plant Growth under Natural Light Conditions Provides Highly Flexible Short-Term Acclimation Properties toward High Light Stress

    PubMed Central

    Schumann, Tobias; Paul, Suman; Melzer, Michael; Dörmann, Peter; Jahns, Peter

    2017-01-01

    Efficient acclimation to different growth light intensities is essential for plant fitness. So far, most studies on light acclimation have been conducted with plants grown under different constant light regimes, but more recent work indicated that acclimation to fluctuating light or field conditions may result in different physiological properties of plants. Thale cress (Arabidopsis thaliana) was grown under three different constant light intensities (LL: 25 μmol photons m−2 s−1; NL: 100 μmol photons m−2 s−1; HL: 500 μmol photons m−2 s−1) and under natural fluctuating light (NatL) conditions. We performed a thorough characterization of the morphological, physiological, and biochemical properties focusing on photo-protective mechanisms. Our analyses corroborated the known properties of LL, NL, and HL plants. NatL plants, however, were found to combine characteristics of both LL and HL grown plants, leading to efficient and unique light utilization capacities. Strikingly, the high energy dissipation capacity of NatL plants correlated with increased dynamics of thylakoid membrane reorganization upon short-term acclimation to excess light. We conclude that the thylakoid membrane organization and particularly the light-dependent and reversible unstacking of grana membranes likely represent key factors that provide the basis for the high acclimation capacity of NatL grown plants to rapidly changing light intensities. PMID:28515734

  3. High tolerance to high-light conditions for the protected species Ariocarpus kotschoubeyanus (Cactaceae).

    PubMed

    Arroyo-Pérez, Erika; Flores, Joel; González-Salvatierra, Claudia; Matías-Palafox, María L; Jiménez-Sierra, Cecilia

    2017-01-01

    We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the 'living rock' cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (ΦPSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photosynthetically active photon flux density for PSII (PFDsat) were also determined from rapid light curves. We found that although the ΦPSII was higher in shaded sites under potential nurse plants than in exposed sites, all values were close to the optimal value of 0.83. The high ΦPSII found for A. kotschoubeyanus plants suggests that they use a great proportion of the absorbed light for photosynthesis, under nurse plants as well as in open spaces. We also found higher NPQ values in exposed sites than in shaded ones but only in Autumn, thus reducing the risk of photoinhibition. In addition, the PFDsat was higher in exposed sites than in shaded ones in Spring, Summer and Autumn, but in Winter there were no differences between treatments. We also found high saturating light levels for ETR (PFDsat higher than 1378 μmol m(-2) s(-1)) in all seasons but in winter for shaded and non-shaded plants. Our findings indicate that A. kotschoubeyanus plants use a great proportion of the light that they absorb for photosynthesis. This high tolerance to high-light conditions could explain why A. kotschoubeyanus do not show preferences for protected sites under nurse plants.

  4. High tolerance to high-light conditions for the protected species Ariocarpus kotschoubeyanus (Cactaceae)

    PubMed Central

    Arroyo-Pérez, Erika; González-Salvatierra, Claudia; Matías-Palafox, María L.; Jiménez-Sierra, Cecilia

    2017-01-01

    Abstract We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the ‘living rock’ cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (ΦPSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photosynthetically active photon flux density for PSII (PFDsat) were also determined from rapid light curves. We found that although the ΦPSII was higher in shaded sites under potential nurse plants than in exposed sites, all values were close to the optimal value of 0.83. The high ΦPSII found for A. kotschoubeyanus plants suggests that they use a great proportion of the absorbed light for photosynthesis, under nurse plants as well as in open spaces. We also found higher NPQ values in exposed sites than in shaded ones but only in Autumn, thus reducing the risk of photoinhibition. In addition, the PFDsat was higher in exposed sites than in shaded ones in Spring, Summer and Autumn, but in Winter there were no differences between treatments. We also found high saturating light levels for ETR (PFDsat higher than 1378 μmol m−2 s−1) in all seasons but in winter for shaded and non-shaded plants. Our findings indicate that A. kotschoubeyanus plants use a great proportion of the light that they absorb for photosynthesis. This high tolerance to high-light conditions could explain why A. kotschoubeyanus do not show preferences for protected sites under nurse plants. PMID:28729902

  5. Chlorophyll b degradation by chlorophyll b reductase under high-light conditions.

    PubMed

    Sato, Rei; Ito, Hisashi; Tanaka, Ayumi

    2015-12-01

    The light-harvesting chlorophyll a/b binding protein complex of photosystem II (LHCII) is the main antenna complex of photosystem II (PSII). Plants change their LHCII content depending on the light environment. Under high-light conditions, the content of LHCII should decrease because over-excitation damages the photosystem. Chlorophyll b is indispensable for accumulating LHCII, and chlorophyll b degradation induces LHCII degradation. Chlorophyll b degradation is initiated by chlorophyll b reductase (CBR). In land plants, NON-YELLOW COLORING 1 (NYC1) and NYC1-Like (NOL) are isozymes of CBR. We analyzed these mutants to determine their functions under high-light conditions. During high-light treatment, the chlorophyll a/b ratio was stable in the wild-type (WT) and nol plants, and the LHCII content decreased in WT plants. The chlorophyll a/b ratio decreased in the nyc1 and nyc1/nol plants, and a substantial degree of LHCII was retained in nyc1/nol plants after the high-light treatment. These results demonstrate that NYC1 degrades the chlorophyll b on LHCII under high-light conditions, thus decreasing the LHCII content. After the high-light treatment, the maximum quantum efficiency of the PSII photochemistry was lower in nyc1 and nyc1/nol plants than in WT and nol plants. A larger light-harvesting system would damage PSII in nyc1 and nyc1/nol plants. The fluorescence spectroscopy of the leaves indicated that photosystem I was also damaged by the excess LHCII in nyc1/nol plants. These observations suggest that chlorophyll b degradation by NYC1 is the initial reaction for the optimization of the light-harvesting capacity under high-light conditions.

  6. Growth condition-dependent sensitivity, photodamage and stress response of Chlamydomonas reinhardtii exposed to high light conditions.

    PubMed

    Fischer, Beat B; Wiesendanger, Manuela; Eggen, Rik I L

    2006-08-01

    Different substrate conditions, such as varying CO(2) concentrations or the presence of acetate, strongly influence the efficiency of photosynthesis in Chlamydomonas reinhardtii. Altered photosynthetic efficiencies affect the susceptibility of algae to the deleterious effects of high light stress, such as the production of reactive oxygen species (ROS) and PSII photodamage. In this study, we investigated the effect of high light on C. reinhardtii grown under photomixotrophy, i.e. in the presence of acetate, as well as under photoautotrophic growth conditions with either low or high CO(2) concentrations. Different parameters such as growth rate, chlorophyll bleaching, singlet oxygen generation, PSII photodamage and the total genomic stress response were analyzed. Although showing a similar degree of PSII photodamage, a much stronger singlet oxygen-specific response and a broader general stress response was observed in acetate and high CO(2)-supplemented cells compared with CO(2)-limited cells. These different photooxidative stress responses were correlated with the individual cellular PSII content and probably directly influenced the ROS production during exposure to high light. In addition, growth of high CO(2)-supplemented cells was more susceptible to high light stress compared with cells grown under CO(2) limitation. The growth of acetate-supplemented cultures, on the other hand, was less affected by high light treatment than cultures grown under high CO(2) concentrations, despite the similar cellular stress. This suggests that the production of ATP by mitochondrial acetate respiration protects the cells from the deleterious effects of high light stress, presumably by providing energy for an effective defense.

  7. Trehalose phosphate synthase overexpression in Parachlorella kessleri improves growth and photosynthetic performance under high light conditions.

    PubMed

    Rathod, Jayant Pralhad; Prakash, Gunjan; Vira, Chaitali; Lali, Arvind M

    2016-11-16

    Parachlorella kessleri is a promising oil-bearing marine alga which shows decreased growth under high light stress. Osmolytes are known to relieve stress by protecting the cell membrane, proteins, and enzymes. Enhanced production of osmolyte (trehalose) was thus used to relieve stress in P. kessleri by overexpression of trehalose phosphate synthase (TPS) gene. Transformed P. kessleri was grown under different light regimes to study the effect of trehalose overproduction on growth. Study of one of the TPS transformants showed increased trehalose as well as increased biomass and decreased pigments, reactive oxygen species, and lipid peroxidation of cell membrane. The improved photosynthetic performance of the transformant was also signified by pulse-amplitude-modulated fluorometric analysis. All of these factors reveal improved stress tolerance under high light conditions by increased trehalose accumulation due to TPS overexpression in P. kessleri.

  8. The significance of cysteine synthesis for acclimation to high light conditions

    PubMed Central

    Speiser, Anna; Haberland, Stefan; Watanabe, Mutsumi; Wirtz, Markus; Dietz, Karl-Josef; Saito, Kazuki; Hell, Rüdiger

    2015-01-01

    Situations of excess light intensity are known to result in the emergence of reactive oxygen species that originate from the electron transport chain in chloroplasts. The redox state of glutathione and its biosynthesis contribute importantly to the plant's response to this stress. In this study we analyzed the significance of cysteine synthesis for long-term acclimation to high light conditions in Arabidopsis thaliana. Emphasis was put on the rate-limiting step of cysteine synthesis, the formation of the precursor O-acetylserine (OAS) that is catalyzed by serine acetyltransferase (SERAT). Wild type Arabidopsis plants responded to the high light condition (800 μmol m−2 s−1 for 10 days) with synthesis of photo-protective anthocyanins, induction of total SERAT activity and elevated glutathione levels when compared to the control condition (100 μmol m−2 s−1). The role of cysteine synthesis in chloroplasts was probed in mutant plants lacking the chloroplast isoform SERAT2;1 (serat2;1) and two knock-out alleles of CYP20-3, a positive interactor of SERAT in the chloroplast. Acclimation to high light resulted in a smaller growth enhancement than wild type in the serat2;1 and cyp20-3 mutants, less induction of total SERAT activity and OAS levels but similar cysteine and glutathione concentrations. Expression analysis revealed no increase in mRNA of the chloroplast SERAT2;1 encoding SERAT2;1 gene but up to 4.4-fold elevated SERAT2;2 mRNA levels for the mitochondrial SERAT isoform. Thus, lack of chloroplast SERAT2;1 activity or its activation by CYP20-3 prevents the full growth response to high light conditions, but the enhanced demand for glutathione is likely mediated by synthesis of OAS in the mitochondria. In conclusion, cysteine synthesis in the chloroplast is important for performance but is dispensable for survival under long-term exposure to high light and can be partially complemented by cysteine synthesis in mitochondria. PMID:25653656

  9. The significance of cysteine synthesis for acclimation to high light conditions.

    PubMed

    Speiser, Anna; Haberland, Stefan; Watanabe, Mutsumi; Wirtz, Markus; Dietz, Karl-Josef; Saito, Kazuki; Hell, Rüdiger

    2014-01-01

    Situations of excess light intensity are known to result in the emergence of reactive oxygen species that originate from the electron transport chain in chloroplasts. The redox state of glutathione and its biosynthesis contribute importantly to the plant's response to this stress. In this study we analyzed the significance of cysteine synthesis for long-term acclimation to high light conditions in Arabidopsis thaliana. Emphasis was put on the rate-limiting step of cysteine synthesis, the formation of the precursor O-acetylserine (OAS) that is catalyzed by serine acetyltransferase (SERAT). Wild type Arabidopsis plants responded to the high light condition (800 μmol m(-2) s(-1) for 10 days) with synthesis of photo-protective anthocyanins, induction of total SERAT activity and elevated glutathione levels when compared to the control condition (100 μmol m(-2) s(-1)). The role of cysteine synthesis in chloroplasts was probed in mutant plants lacking the chloroplast isoform SERAT2;1 (serat2;1) and two knock-out alleles of CYP20-3, a positive interactor of SERAT in the chloroplast. Acclimation to high light resulted in a smaller growth enhancement than wild type in the serat2;1 and cyp20-3 mutants, less induction of total SERAT activity and OAS levels but similar cysteine and glutathione concentrations. Expression analysis revealed no increase in mRNA of the chloroplast SERAT2;1 encoding SERAT2;1 gene but up to 4.4-fold elevated SERAT2;2 mRNA levels for the mitochondrial SERAT isoform. Thus, lack of chloroplast SERAT2;1 activity or its activation by CYP20-3 prevents the full growth response to high light conditions, but the enhanced demand for glutathione is likely mediated by synthesis of OAS in the mitochondria. In conclusion, cysteine synthesis in the chloroplast is important for performance but is dispensable for survival under long-term exposure to high light and can be partially complemented by cysteine synthesis in mitochondria.

  10. Spring Ephemerals Adapt to Extremely High Light Conditions via an Unusual Stabilization of Photosystem II

    PubMed Central

    Tu, Wenfeng; Li, Yang; Liu, Wu; Wu, Lishuan; Xie, Xiaoyan; Zhang, Yuanming; Wilhelm, Christian; Yang, Chunhong

    2016-01-01

    Ephemerals, widely distributed in the Gobi desert, have developed significant characteristics to sustain high photosynthetic efficiency under high light (HL) conditions. Since the light reaction is the basis for photosynthetic conversion of solar energy to chemical energy, the photosynthetic performances in thylakoid membrane of the spring ephemerals in response to HL were studied. Three plant species, namely two C3 spring ephemeral species of Cruciferae: Arabidopsis pumila (A. pumila) and Sisymbrium altissimum (S. altissimum), and the model plant Arabidopsis thaliana (A. thaliana) were chosen for the study. The ephemeral A. pumila, which is genetically close to A. thaliana and ecologically in the same habitat as S. altissimum, was used to avoid complications arising from the superficial differences resulted from comparing plants from two extremely contrasting ecological groups. The findings manifested that the ephemerals showed significantly enhanced activities of photosystem (PS) II under HL conditions, while the activities of PSII in A. thaliana were markedly decreased under the same conditions. Detailed analyses of the electron transport processes revealed that the increased plastoquinone pool oxidization, together with the enhanced PSI activities, ensured a lowered excitation pressure to PSII of both ephemerals, and thus facilitated the photosynthetic control to avoid photodamage to PSII. The analysis of the reaction centers of the PSs, both in terms of D1 protein turnover kinetics and the long-term adaptation, revealed that the unusually stable PSs structure provided the basis for the ephemerals to carry out high photosynthetic performances. It is proposed that the characteristic photosynthetic performances of ephemerals were resulted from effects of the long-term adaptation to the harsh environments. PMID:26779223

  11. Photoacclimation of cultured strains of the cyanobacterium Microcystis aeruginosa to high-light and low-light conditions.

    PubMed

    Bañares-España, Elena; Kromkamp, Jacco C; López-Rodas, Victoria; Costas, Eduardo; Flores-Moya, Antonio

    2013-03-01

    The cyanobacterium Microcystis aeruginosa forms blooms that can consist of colonies. We have investigated how M. aeruginosa acclimatizes to changing light conditions such as can occur during blooms. Three different strains were exposed to two irradiance levels: lower (LL) and higher (HL) than the irradiance-onset saturation parameter. We measured the photosynthetic pigment concentrations, PSII photochemical efficiency, electron transport rate (ETR), irradiance-saturated ETR and ETR efficiency. The relationship between ETR and photosynthetic oxygen production and the excess in PSII capacity were also studied for one strain. Higher values of chlorophyll a and phycocyanin and lower values of total carotenoids were found under LL conditions in the three strains. The strains showed clear differences in the irradiance-saturated ETR and in ETR efficiency under both LL and HL treatments. No differences were found in the linear relationship between ETR and photosynthetic oxygen production under both irradiance treatments. LL-acclimated cells showed higher PSII excess capacity than HL ones, possibly because their higher pigment content could result in a higher light stress than HL cells when forming surface blooms. The fact that the genetically different strains show different photosynthetic physiologies suggests that the very dynamic light climate observed in lakes may allow their coexistence. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  12. Diminished photoinhibition is involved in high photosynthetic capacities in spring ephemeral Berteroa incana under strong light conditions.

    PubMed

    Tu, Wenfeng; Li, Yang; Zhang, Yuanming; Zhang, Lei; Liu, Huaying; Liu, Cheng; Yang, Chunhong

    2012-10-15

    Berteroa incana (B. incana), a spring ephemeral species of Brassicaceae, possesses very high photosynthetic capacities at high irradiances. Exploring the mechanism of the high light use efficiency of B. incana under strong light conditions may help to explore mechanisms of plants' survival strategies. Therefore, the photosynthetic characteristics of B. incana grown under three different light intensities (field conditions (field): 200-1500μmolphotonsm(-2)s(-1); greenhouse high light (HL) conditons: 600μmolphotonsm(-2)s(-1); and greenhouse low light (LL) conditions: 100μmolphotonsm(-2)s(-1)) were investigated and compared with those of the model plant Arabidopsis thaliana (A. thaliana). Our results revealed that B. incana behaved differently in adjusting its photosynthetic activities under both HL and LL conditions compared with what A. thaliana did under the same conditions, suggesting that the potential of photosynthetic capacity of B. incana might be enhanced under strong light conditions. Under LL conditions, B. incana reached its maximum photosynthetic activity at a much higher light intensity than A. thaliana did, although their maximum photochemical efficiency of photosystem II (PSII) (F(v)/F(m)) was almost the same. When grown under HL conditions, B. incana showed much higher photosynthetic capacity than A. thaliana. A detailed analysis of the OJIP transient kinetics of B. incana under HL and LL conditions revealed that HL-grown B. incana possessed not only a high ability in regulating photosystem stoichiometry that ensured high linear electron transport, but also an enhanced availability of oxidized plastoquinone (PQ) pool which reduced non-photochemical quenching (NPQ), especially its slow components qT and qI, and increased the photochemical efficiency, which in turn, increased the electron transport. We suggest that the high ability in regulating photosystem stoichiometry and the high level of the availability of oxidized PQ pool in B. incana under

  13. Tribological Evaluation of Candidate Gear Materials Operating Under Light Loads in Highly Humid Conditions

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Thomas, Fransua; Leak, Olivia Ann

    2015-01-01

    A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9N, 2.7ms) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via a secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed in these

  14. Tribological Evaluation of Candidate Gear Materials Operating Under Light Loads in Highly Humid Conditions

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Thomas, Fransua; Leak, Olivia Ann

    2015-01-01

    A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9 N, 2.7 m/s) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (approx. 0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via the secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed

  15. Energy dissipation pathways in Photosystem 2 of the diatom, Phaeodactylum tricornutum, under high-light conditions.

    PubMed

    Kuzminov, Fedor I; Gorbunov, Maxim Y

    2016-02-01

    To prevent photooxidative damage under supraoptimal light, photosynthetic organisms evolved mechanisms to thermally dissipate excess absorbed energy, known as non-photochemical quenching (NPQ). Here we quantify NPQ-induced alterations in light-harvesting processes and photochemical reactions in Photosystem 2 (PS2) in the pennate diatom Phaeodactylum tricornutum. Using a combination of picosecond lifetime analysis and variable fluorescence technique, we examined the dynamics of NPQ activation upon transition from dark to high light. Our analysis revealed that NPQ activation starts with a 2-3-fold increase in the rate constant of non-radiative charge recombination in the reaction center (RC); however, this increase is compensated with a proportional increase in the rate constant of back reactions. The resulting alterations in photochemical processes in PS2 RC do not contribute directly to quenching of antenna excitons by the RC, but favor non-radiative dissipation pathways within the RC, reducing the yields of spin conversion of the RC chlorophyll to the triplet state. The NPQ-induced changes in the RC are followed by a gradual ~ 2.5-fold increase in the yields of thermal dissipation in light-harvesting complexes. Our data suggest that thermal dissipation in light-harvesting complexes is the major sink for NPQ; RCs are not directly involved in the NPQ process, but could contribute to photoprotection via reduction in the probability of (3)Chl formation.

  16. Partitioning of absorbed light energy differed between the sun-exposed side and the shaded side of apple fruits under high light conditions.

    PubMed

    Chen, Changsheng; Zhang, Di; Li, Pengmin; Ma, Fengwang

    2012-11-01

    Fractions of absorbed light energy consumed via photochemistry and different thermal dissipation processes was quantified and compared between the sun-exposed peel and the shaded peel of apple fruits at different developmental stages. During fruit development, the fraction of absorbed light consumed via photochemistry was no more than 7% in the sun-exposed peel and no more than 5% in the shaded peel under high light conditions. Under high light, the fraction of absorbed light energy consumed via light dependent thermal dissipation was higher whereas that via constitutive thermal dissipation was lower in the sun-exposed peel. The light dependent thermal dissipation in the sun-exposed peel mainly depended on the xanthophyll cycle, and the xanthophyll cycle pool size was significantly larger in the sun-exposed peel than in the shaded peel. The light dependent thermal dissipation in the shaded peel was dependent on both the xanthophyll cycle and the presence of inactivated reaction centers. Under high light conditions, the densities of both Q(A)-reducing reaction centers and Q(B)-reducing reaction centers decreased faster in the shaded peel than in the sun-exposed peel. The thermal dissipation related to photoinhibition increased and then kept unchanged in the sun-exposed peel but decreased in the shaded peel during fruit development. We conclude that under high light intensities, fruit peel looses the excess energy in order of predominance: first by the xanthophyll cycle, then the thermal dissipation related to photoinhibition, next through inactivated reaction centers, and finally by constitutive thermal dissipation.

  17. Study of High Fluence Radiation-induced Swelling and Hardening under Light Water Reactor Conditions

    SciTech Connect

    Golubov, Stanislav I.; Barashev, Alexander V.; Stoller, Roger E.

    2016-09-01

    This report documents a comprehensive model that has been developed to enable simulations of microstructural evolution under the irradiation conditions typical of light water reactor (LWR) internal components. The model, which accounts cascade production of point defects and vacancy, interstitial faulted dislocation loops, interstitial clusters migrating one-dimensionally and the evolution of the network dislocation structure, has been parameterized to account damage accumulation in austenitic stainless steels. Nucleation and growth of an ensemble of cavities is based on accounting the residual and produced by irradiation He atoms and existence of the dislocation and production biases. Additional applications and potential future developments for the model are also discussed.

  18. Melt Conditioning of Light Metals by Application of High Shear for Improved Microstructure and Defect Control

    NASA Astrophysics Data System (ADS)

    Patel, Jayesh B.; Yang, Xinliang; Mendis, Chamini L.; Fan, Zhongyun

    2017-04-01

    Casting is the first step toward the production of majority of metal products whether the final processing step is casting or other thermomechanical processes such as extrusion or forging. The high shear melt conditioning provides an easily adopted pathway to producing castings with a more uniform fine-grained microstructure along with a more uniform distribution of the chemical composition leading to fewer defects as a result of reduced shrinkage porosities and the presence of large oxide films through the microstructure. The effectiveness of high shear melt conditioning in improving the microstructure of processes used in industry illustrates the versatility of the high shear melt conditioning technology. The application of high shear process to direct chill and twin roll casting process is demonstrated with examples from magnesium melts.

  19. High Efficiency Light Harvesting by Carotenoids in the LH2 Complex from Photosynthetic Bacteria: Unique Adaptation to Growth under Low-Light Conditions

    PubMed Central

    2015-01-01

    Rhodopin, rhodopinal, and their glucoside derivatives are carotenoids that accumulate in different amounts in the photosynthetic bacterium, Rhodoblastus (Rbl.) acidophilus strain 7050, depending on the intensity of the light under which the organism is grown. The different growth conditions also have a profound effect on the spectra of the bacteriochlorophyll (BChl) pigments that assemble in the major LH2 light-harvesting pigment–protein complex. Under high-light conditions the well-characterized B800-850 LH2 complex is formed and accumulates rhodopin and rhodopin glucoside as the primary carotenoids. Under low-light conditions, a variant LH2, denoted B800-820, is formed, and rhodopinal and rhodopinal glucoside are the most abundant carotenoids. The present investigation compares and contrasts the spectral properties and dynamics of the excited states of rhodopin and rhodopinal in solution. In addition, the systematic differences in pigment composition and structure of the chromophores in the LH2 complexes provide an opportunity to explore the effect of these factors on the rate and efficiency of carotenoid-to-BChl energy transfer. It is found that the enzymatic conversion of rhodopin to rhodopinal by Rbl. acidophilus 7050 grown under low-light conditions results in nearly 100% carotenoid-to-BChl energy transfer efficiency in the LH2 complex. This comparative analysis provides insight into how photosynthetic systems are able to adapt and survive under challenging environmental conditions. PMID:25171303

  20. High efficiency light harvesting by carotenoids in the LH2 complex from photosynthetic bacteria: unique adaptation to growth under low-light conditions.

    PubMed

    Magdaong, Nikki M; LaFountain, Amy M; Greco, Jordan A; Gardiner, Alastair T; Carey, Anne-Marie; Cogdell, Richard J; Gibson, George N; Birge, Robert R; Frank, Harry A

    2014-09-25

    Rhodopin, rhodopinal, and their glucoside derivatives are carotenoids that accumulate in different amounts in the photosynthetic bacterium, Rhodoblastus (Rbl.) acidophilus strain 7050, depending on the intensity of the light under which the organism is grown. The different growth conditions also have a profound effect on the spectra of the bacteriochlorophyll (BChl) pigments that assemble in the major LH2 light-harvesting pigment-protein complex. Under high-light conditions the well-characterized B800-850 LH2 complex is formed and accumulates rhodopin and rhodopin glucoside as the primary carotenoids. Under low-light conditions, a variant LH2, denoted B800-820, is formed, and rhodopinal and rhodopinal glucoside are the most abundant carotenoids. The present investigation compares and contrasts the spectral properties and dynamics of the excited states of rhodopin and rhodopinal in solution. In addition, the systematic differences in pigment composition and structure of the chromophores in the LH2 complexes provide an opportunity to explore the effect of these factors on the rate and efficiency of carotenoid-to-BChl energy transfer. It is found that the enzymatic conversion of rhodopin to rhodopinal by Rbl. acidophilus 7050 grown under low-light conditions results in nearly 100% carotenoid-to-BChl energy transfer efficiency in the LH2 complex. This comparative analysis provides insight into how photosynthetic systems are able to adapt and survive under challenging environmental conditions.

  1. Starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions.

    PubMed

    Takeshita, Tsuyoshi; Ota, Shuhei; Yamazaki, Tomokazu; Hirata, Aiko; Zachleder, Vilém; Kawano, Shigeyuki

    2014-04-01

    The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m(-2)s(-1)). The 12:12-h light-dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns.

  2. Synchrotron Radiation and High Pressure: New Light on Materials Under Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Hemley, Russell

    2005-03-01

    Current technological advances now make it possible to perform experiments on materials subjected to static or sustained conditions up to multimegabar pressures (>300 GPa) and from cryogenic temperatures to several thousand degrees (˜0.5 eV range). With these techniques, densities of condensed matter can be increased over an order of magnitude, causing numerous transformations and new physical and chemical phenomena to occur. Growth in this area largely been made possible by accelerating developments in diamond-anvil cell methods coupled with new synchrotron radiation techniques. Significant advances have occurred in x-ray diffraction, spectroscopy, inelastic scattering, radiography, and infrared spectroscopy. With recent developments, structure refinements based on polycrystalline data up to multimegabar pressures have been possible. Single-crystal methods have been extended to megabar pressure, with the prospect of full crystallographic refinements. `Three- dimensional' diffraction data can be collected for determining strength, deformation, and elastic tensors at high P-T conditions. Studies carried out during the past three years provide numerous breakthroughs in high-pressure x-ray spectroscopy and a broad range of inelastic scattering methods. Other experiments have exploited the use of x-ray radiography over a range of pressures. Finally, synchrotron infrared measurements have revealed a wealth of high-pressure phenomena, particularly for molecular systems. Examples to be discussed include investigations of dense hydrogen; transformations in molecular materials; novel ceramics; new types of superconductors, electronic, and magnetic materials; and liquids and amorphous materials.

  3. Synchrotron radiation and high pressure: new light on materials under extreme conditions.

    PubMed

    Hemley, Russell J; Mao, Ho-kwang; Struzhkin, Viktor V

    2005-03-01

    With the steady development of static high-pressure techniques in recent years, it is now possible to probe in increasing detail the novel behavior of materials subjected to extreme conditions of multimegabar pressures (>300 GPa) and temperatures from cryogenic states to thousands of degrees. By and large, the growth in this area has been made possible by accelerating developments in diamond-anvil cell methods coupled with new synchrotron radiation techniques. Significant advances have occurred in high-pressure powder and single-crystal diffraction, spectroscopy, inelastic scattering, radiography, and infrared spectroscopy. A brief overview of selected highlights in each of these classes of experiments is presented that illustrate both the state-of-the-art as well as current technical and scientific challenges. The experiments have been made possible by the development of a spectrum of new techniques at both third- and second-generation high-energy sources together with key advances in high-pressure technology. The results have implications for a variety of problems in physics, chemistry, materials science, geoscience, planetary science, and biology.

  4. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions

    PubMed Central

    Gu, Junfei; Zhou, Zhenxiang; Li, Zhikang; Chen, Ying; Wang, Zhiqin; Zhang, Hao; Yang, Jianchang

    2017-01-01

    Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS). Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ) to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl) and a normally pigmented control (Z802) were subjected to high (HL) and low light (LL). Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC) binding proteins, electron transport rates (ETR), photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size. PMID:28676818

  5. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions.

    PubMed

    Gu, Junfei; Zhou, Zhenxiang; Li, Zhikang; Chen, Ying; Wang, Zhiqin; Zhang, Hao; Yang, Jianchang

    2017-01-01

    Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS). Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ) to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl) and a normally pigmented control (Z802) were subjected to high (HL) and low light (LL). Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC) binding proteins, electron transport rates (ETR), photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size.

  6. High efficiency incandescent lighting

    SciTech Connect

    Bermel, Peter; Ilic, Ognjen; Chan, Walker R.; Musabeyoglu, Ahmet; Cukierman, Aviv Ruben; Harradon, Michael Robert; Celanovic, Ivan; Soljacic, Marin

    2014-09-02

    Incandescent lighting structure. The structure includes a thermal emitter that can, but does not have to, include a first photonic crystal on its surface to tailor thermal emission coupled to, in a high-view-factor geometry, a second photonic filter selected to reflect infrared radiation back to the emitter while passing visible light. This structure is highly efficient as compared to standard incandescent light bulbs.

  7. High Intensity Lights

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Xenon arc lamps developed during the Apollo program by Streamlight, Inc. are the basis for commercial flashlights and emergency handlights. These are some of the brightest portable lights made. They throw a light some 50 times brighter than automobile high beams and are primarily used by police and military. The light penetrates fog and smoke and returns less back-scatter light. They are operated on portable power packs as boat and auto batteries. An infrared model produces totally invisible light for covert surveillance.

  8. Light energy dissipation under water stress conditions

    SciTech Connect

    Stuhlfauth, T.; Scheuermann, R.; Fock, H.P. )

    1990-04-01

    Using {sup 14}CO{sub 2} gas exchange and metabolite analyses, stomatal as well as total internal CO{sub 2} uptake and evolution were estimated. Pulse modulated fluorescence was measured during induction and steady state of photosynthesis. Leaf water potential of Digitalis lanata EHRH. plants decreased to {minus}2.5 megapascals after withholding irrigation. By osmotic adjustment, leaves remained turgid and fully exposed to irradiance even at severe water stress. Due to the stress-induced reduction of stomatal conductance, the stomatal CO{sub 2} exchange was drastically reduced, whereas the total CO{sub 2} uptake and evolution were less affected. Stomatal closure induced an increase in the reassimilation of internally evolved CO{sub 2}. This CO{sub 2}-recycling consumes a significant amount of light energy in the form of ATP and reducing equivalents. As a consequence, the metabolic demand for light energy is only reduced by about 40%, whereas net photosynthesis is diminished by about 70% under severe stress conditions. By CO{sub 2} recycling, carbon flux, enzymatic substrate turnover and consumption of light energy were maintained at high levels, which enabled the plant to recover rapidly after rewatering. In stressed D. lanata plants a variable fluorescence quenching mechanism, termed coefficient of actinic light quenching, was observed. Besides water conservation, light energy dissipation is essential and involves regulated metabolic variations.

  9. High Brightness OLED Lighting

    SciTech Connect

    Spindler, Jeffrey; Kondakova, Marina; Boroson, Michael; Hamer, John

    2016-05-25

    In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

  10. Early Transcriptional Defense Responses in Arabidopsis Cell Suspension Culture under High-Light Conditions1[C][W][OA

    PubMed Central

    González-Pérez, Sergio; Gutiérrez, Jorge; García-García, Francisco; Osuna, Daniel; Dopazo, Joaquín; Lorenzo, Óscar; Revuelta, José L.; Arellano, Juan B.

    2011-01-01

    The early transcriptional defense responses and reactive oxygen species (ROS) production in Arabidopsis (Arabidopsis thaliana) cell suspension culture (ACSC), containing functional chloroplasts, were examined at high light (HL). The transcriptional analysis revealed that most of the ROS markers identified among the 449 transcripts with significant differential expression were transcripts specifically up-regulated by singlet oxygen (1O2). On the contrary, minimal correlation was established with transcripts specifically up-regulated by superoxide radical or hydrogen peroxide. The transcriptional analysis was supported by fluorescence microscopy experiments. The incubation of ACSC with the 1O2 sensor green reagent and 2′,7′-dichlorofluorescein diacetate showed that the 30-min-HL-treated cultures emitted fluorescence that corresponded with the production of 1O2 but not of hydrogen peroxide. Furthermore, the in vivo photodamage of the D1 protein of photosystem II indicated that the photogeneration of 1O2 took place within the photosystem II reaction center. Functional enrichment analyses identified transcripts that are key components of the ROS signaling transduction pathway in plants as well as others encoding transcription factors that regulate both ROS scavenging and water deficit stress. A meta-analysis examining the transcriptional profiles of mutants and hormone treatments in Arabidopsis showed a high correlation between ACSC at HL and the fluorescent mutant family of Arabidopsis, a producer of 1O2 in plastids. Intriguingly, a high correlation was also observed with ABA deficient1 and more axillary growth4, two mutants with defects in the biosynthesis pathways of two key (apo)carotenoid-derived plant hormones (i.e. abscisic acid and strigolactones, respectively). ACSC has proven to be a valuable system for studying early transcriptional responses to HL stress. PMID:21531897

  11. Terrain on Europa under Changing Lighting Conditions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These images obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft show the same region of Europa under different lighting conditions. The upper image was obtained on June 28th, 1996 during Galileo's first orbit around Jupiter under 'high-sun' conditions -- the equivalent of taking a picture from a high altitude at noon (with the sun directly overhead). Note that albedo (light/dark) features are emphasized. Compare this to the lower image containing a higher-resolution inset. This (inset) image was taken on November 6th, 1996 during the spacecraft's third orbit under 'low-sun' illumination -- the equivalent of taking a picture from a high altitude at sunrise or sunset. Note that in this image the albedo features are not readily apparent. Instead, the topography of the terrain is emphasized. Planetary geologists use information from images acquired under a variety of lighting conditions to identify different types of structures and interpret how they formed. Note that the bright linear features in the upper image are seen to be ridges in the lower image. The circular feature on the right side of both images, Cilix, is approximately 25 kilometers (15 miles) across.

    The area seen in the upper image is 312 kilometers (187 miles) by 570 kilometers (342 miles) across; the area covered by the inset is 36 kilometers (22 miles) by 315 kilometers (190 miles) across. Both of these images are centered near 2 South latitude, 185 West longitude. North is to the top of the frames.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  12. Lighting Condition Analysis for Mars Moon Phobos

    NASA Technical Reports Server (NTRS)

    Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; De Carufel, Guy

    2016-01-01

    A manned mission to Phobos may be an important precursor and catalyst for the human exploration of Mars, as it will fully demonstrate the technologies for a successful Mars mission. A comprehensive understanding of Phobos' environment such as lighting condition and gravitational acceleration are essential to the mission success. The lighting condition is one of many critical factors for landing zone selection, vehicle power subsystem design, and surface mobility vehicle path planning. Due to the orbital characteristic of Phobos, the lighting condition will change dramatically from one Martian season to another. This study uses high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, the Earth, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos' state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting condition over one Martian year are presented in this paper, which include length of solar eclipse, average solar radiation intensity, surface exposure time, total maximum solar energy, and total surface solar energy (constrained by incident angle). The results show that Phobos' solar eclipse time changes throughout the Martian year with the maximum eclipse time occurring during the Martian spring and fall equinox and no solar eclipse during the Martian summer and winter solstice. Solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice. Total surface exposure time is longer near the north pole and around the anti- Mars point. Total maximum solar energy is larger around the anti-Mars point. Total surface solar energy is higher around the anti-Mars point near the equator. The

  13. Redox-Dependent Modulation of Anthocyanin Biosynthesis by the TCP Transcription Factor TCP15 during Exposure to High Light Intensity Conditions in Arabidopsis.

    PubMed

    Viola, Ivana L; Camoirano, Alejandra; Gonzalez, Daniel H

    2016-01-01

    TCP proteins integrate a family of transcription factors involved in the regulation of developmental processes and hormone responses. It has been shown that most members of class I, one of the two classes in which the TCP family is divided, contain a conserved Cys that leads to inhibition of DNA binding when oxidized. In this work, we describe that the class-I TCP protein TCP15 inhibits anthocyanin accumulation during exposure of plants to high light intensity by modulating the expression of transcription factors involved in the induction of anthocyanin biosynthesis genes, as suggested by the study of plants that express TCP15 from the 35SCaMV promoter and mutants in TCP15 and the related gene TCP14. In addition, the effect of TCP15 on anthocyanin accumulation is lost after prolonged incubation under high light intensity conditions. We provide evidence that this is due to inactivation of TCP15 by oxidation of Cys-20 of the TCP domain. Thus, redox modulation of TCP15 activity in vivo by high light intensity may serve to adjust anthocyanin accumulation to the duration of exposure to high irradiation conditions.

  14. Object detectability at increased ambient lighting conditions

    SciTech Connect

    Pollard, Benjamin J.; Chawla, Amarpreet S.; Delong, David M.; Hashimoto, Noriyuki; Samei, Ehsan

    2008-06-15

    Under typical dark conditions encountered in diagnostic reading rooms, a reader's pupils will contract and dilate as the visual focus intermittently shifts between the high luminance display and the darker background wall, resulting in increased visual fatigue and the degradation of diagnostic performance. A controlled increase of ambient lighting may, however, reduce the severity of these pupillary adjustments by minimizing the difference between the luminance level to which the eyes adapt while viewing an image (L{sub adp}) and the luminance level of diffusely reflected light from the area surrounding the display (L{sub s}). Although ambient lighting in reading rooms has conventionally been kept at a minimum to maintain the perceived contrast of film images, proper Digital Imaging and Communications in Medicine (DICOM) calibration of modern medical-grade liquid crystal displays can compensate for minor lighting increases with very little loss of image contrast. This paper describes two psychophysical studies developed to evaluate and refine optimum reading room ambient lighting conditions through the use of observational tasks intended to simulate real clinical practices. The first study utilized the biologic contrast response of the human visual system to determine a range of representative L{sub adp} values for typical medical images. Readers identified low contrast horizontal objects in circular foregrounds of uniform luminance (5, 12, 20, and 30 cd/m{sup 2}) embedded within digitized mammograms. The second study examined the effect of increased ambient lighting on the detection of subtle objects embedded in circular foregrounds of uniform luminance (5, 12, and 35 cd/m{sup 2}) centered within a constant background of 12 cd/m{sup 2} luminance. The images were displayed under a dark room condition (1 lux) and an increased ambient lighting level (50 lux) such that the luminance level of the diffusely reflected light from the background wall was approximately

  15. Object detectability at increased ambient lighting conditions.

    PubMed

    Pollard, Benjamin J; Chawla, Amarpreet S; Delong, David M; Hashimoto, Noriyuki; Samei, Ehsan

    2008-06-01

    Under typical dark conditions encountered in diagnostic reading rooms, a reader's pupils will contract and dilate as the visual focus intermittently shifts between the high luminance display and the darker background wall, resulting in increased visual fatigue and the degradation of diagnostic performance. A controlled increase of ambient lighting may, however, reduce the severity of these pupillary adjustments by minimizing the difference between the luminance level to which the eyes adapt while viewing an image (L(adp)) and the luminance level of diffusely reflected light from the area surrounding the display (L(s)). Although ambient lighting in reading rooms has conventionally been kept at a minimum to maintain the perceived contrast of film images, proper Digital Imaging and Communications in Medicine (DICOM) calibration of modern medical-grade liquid crystal displays can compensate for minor lighting increases with very little loss of image contrast. This paper describes two psychophysical studies developed to evaluate and refine optimum reading room ambient lighting conditions through the use of observational tasks intended to simulate real clinical practices. The first study utilized the biologic contrast response of the human visual system to determine a range of representative L(adp) values for typical medical images. Readers identified low contrast horizontal objects in circular foregrounds of uniform luminance (5, 12, 20, and 30 cd/m2) embedded within digitized mammograms. The second study examined the effect of increased ambient lighting on the detection of subtle objects embedded in circular foregrounds of uniform luminance (5, 12, and 35 cd/m2) centered within a constant background of 12 cd/m2 luminance. The images were displayed under a dark room condition (1 lux) and an increased ambient lighting level (50 lux) such that the luminance level of the diffusely reflected light from the background wall was approximately equal to the image L(adp) value of

  16. Co-expression of cytochrome b561 and ascorbate oxidase in leaves of wild watermelon under drought and high light conditions.

    PubMed

    Nanasato, Yoshihiko; Akashi, Kinya; Yokota, Akiho

    2005-09-01

    Despite carrying out C3 photosynthesis, wild watermelon (Citrullus lanatus sp.) exhibits exceedingly good tolerance to severe drought at high light intensities. However, the mechanism(s) by which this plant protects itself from photodamage has yet to be elucidated. In this study, we characterized wild watermelon cytochrome b561 (cyt b561), which potentially mediates regeneration of apoplastic ascorbate by transferring electrons from cytosolic ascorbate across the plasma membrane. Two cDNA species for wild watermelon cyt b561, designated CLb561A and CLb561B, were isolated. Levels of both CLb561A mRNA and protein were significantly elevated in the leaves during drought at a light intensity of 700 micromol photons m(-2) s(-1). The transcript of CLb561B was detected to a much lesser extent, but no CLb561B protein was produced under any condition used in this study. A transient expression assay with the CLb561A::green fluorescent protein fusion construct showed clear fluorescence on the plasma membrane of onion epidermal cells. The CLb561A protein was enriched in the plasma membrane fraction in leaves of transgenic tobacco expressing CLb561A. Moreover, the high activity of apoplastic ascorbate oxidase (AO), which was able to dispose of cyt b561-transferred reducing equivalents, increased in leaves of wild watermelon grown at high light intensity, but not lower light intensities. Taken together, these observations suggest the occurrence of a novel pathway for excess light energy dissipation in wild watermelon leaves, where excessive energy absorbed by chloroplasts can be transported to and dissipated safely in the apoplasts through the cooperative action of cyt b561 and AO.

  17. Lighting Condition Analysis for Mars' Moon Phobos

    NASA Technical Reports Server (NTRS)

    Li, Zu Qun; de Carufel, Guy; Crues, Edwin Z.; Bielski, Paul

    2016-01-01

    This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, and radiant exposure for both sun tracking and fixed solar arrays. The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian northern spring and fall seasons and no eclipses during the Martian northern summer and winter seasons; solar radiation intensity is close to minimum in late spring and close to maximum in late fall; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility.

  18. Lighting Condition Analysis for Mars' Moon Phobos

    NASA Technical Reports Server (NTRS)

    Li, Zu Qun; de Carufel, Guy; Crues, Edwin Z.; Bielski, Paul

    2016-01-01

    This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, available energy per unit area for sun tracking arrays, and available energy per unit area for fixed arrays (constrained by incident angle). The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian spring and fall seasons and no eclipses during the Martian summer and winter seasons; solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility.

  19. High-resolution live imaging of plant growth in near physiological bright conditions using light sheet fluorescence microscopy.

    PubMed

    Maizel, Alexis; von Wangenheim, Daniel; Federici, Fernán; Haseloff, Jim; Stelzer, Ernst H K

    2011-10-01

    Most plant growth occurs post-embryonically and is characterized by the constant and iterative formation of new organs. Non-invasive time-resolved imaging of intact, fully functional organisms allows studies of the dynamics involved in shaping complex organisms. Conventional and confocal fluorescence microscopy suffer from limitations when whole living organisms are imaged at single-cell resolution. We applied light sheet-based fluorescence microscopy to overcome these limitations and study the dynamics of plant growth. We designed a special imaging chamber in which the plant is maintained vertically under controlled illumination with its leaves in the air and its root in the medium. We show that minimally invasive, multi-color, three-dimensional imaging of live Arabidopsis thaliana samples can be achieved at organ, cellular and subcellular scales over periods of time ranging from seconds to days with minimal damage to the sample. We illustrate the capabilities of the method by recording the growth of primary root tips and lateral root primordia over several hours. This allowed us to quantify the contribution of cell elongation to the early morphogenesis of lateral root primordia and uncover the diurnal growth rhythm of lateral roots. We demonstrate the applicability of our approach at varying spatial and temporal scales by following the division of plant cells as well as the movement of single endosomes in live growing root samples. This multi-dimensional approach will have an important impact on plant developmental and cell biology and paves the way to a truly quantitative description of growth processes at several scales. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  20. Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions

    PubMed Central

    Joubert, Chandré; Young, Philip R.; Eyéghé-Bickong, Hans A.; Vivier, Melané A.

    2016-01-01

    Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates. The primary objective was therefore to identify UVB-specific responses on berry processes and metabolites and distinguish them from those responses elicited by variations in light incidence. Canopy manipulation at the bunch zone via early leaf removal, combined with UVB-excluding acrylic sheets installed over the bunch zones resulted in four bunch microclimates: (1) HL (control); (2) LL (control); (3) HL with UVB attenuation and (4) LL with UVB attenuation. Metabolite profiles of three berry developmental stages showed predictable changes to known UV-responsive compound classes in a typical UV acclimation (versus UV damage) response. Interestingly, the berries employed carotenoids and the associated xanthophyll cycles to acclimate to UV exposure and the berry responses differed between HL and LL conditions, particularly in the developmental stages where berries are still photosynthetically active. The developmental stage of the berries was an important factor to consider in interpreting the data. The green berries responded to the different exposure and/or UVB attenuation signals with metabolites that indicate that the berries actively managed its metabolism in relation to the exposure levels, displaying metabolic plasticity in the photosynthesis-related metabolites. Core processes such as photosynthesis, photo-inhibition and acclimation were maintained by differentially modulating metabolites under the four treatments. Ripe berries also responded metabolically to the light quality and quantity, but mostly formed compounds (volatiles and polyphenols) that have direct antioxidant and/or

  1. Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions.

    PubMed

    Joubert, Chandré; Young, Philip R; Eyéghé-Bickong, Hans A; Vivier, Melané A

    2016-01-01

    Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates. The primary objective was therefore to identify UVB-specific responses on berry processes and metabolites and distinguish them from those responses elicited by variations in light incidence. Canopy manipulation at the bunch zone via early leaf removal, combined with UVB-excluding acrylic sheets installed over the bunch zones resulted in four bunch microclimates: (1) HL (control); (2) LL (control); (3) HL with UVB attenuation and (4) LL with UVB attenuation. Metabolite profiles of three berry developmental stages showed predictable changes to known UV-responsive compound classes in a typical UV acclimation (versus UV damage) response. Interestingly, the berries employed carotenoids and the associated xanthophyll cycles to acclimate to UV exposure and the berry responses differed between HL and LL conditions, particularly in the developmental stages where berries are still photosynthetically active. The developmental stage of the berries was an important factor to consider in interpreting the data. The green berries responded to the different exposure and/or UVB attenuation signals with metabolites that indicate that the berries actively managed its metabolism in relation to the exposure levels, displaying metabolic plasticity in the photosynthesis-related metabolites. Core processes such as photosynthesis, photo-inhibition and acclimation were maintained by differentially modulating metabolites under the four treatments. Ripe berries also responded metabolically to the light quality and quantity, but mostly formed compounds (volatiles and polyphenols) that have direct antioxidant and

  2. High Intensity Lighting

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Nightime illumination is an important part of round-the-clock pre-launch preparations because NASA uses TV and film cameras to monitor each step of the preliminaries and at times to identify the cause of malfunction during countdown. Generating a one billion candlepower beam visible 50 miles away, the lamps developed by Duro-Test Corporation provide daylight quality light that eliminates color distortion in film and TV coverage. The lighting system was first used at Kennedy Space Center in 1968 for the launch of Apollo 8. Modified versions are available in wide range of applications, such as the battery of spotlights with colored filters that light up Niagara Falls, as well as the lamps used in the projectors for the Smithsonian's IMAX Theatre, indoor theatres with supersized screens and outdoor projection systems.

  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. High voltage pulse conditioning

    DOEpatents

    Springfield, Ray M.; Wheat, Jr., Robert M.

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  5. Prevention of polymorphic light eruption with a sunscreen of very high protection level against UVB and UVA radiation under standardized photodiagnostic conditions.

    PubMed

    Schleyer, Verena; Weber, Oliver; Yazdi, Amir; Benedix, Frauke; Dietz, Klaus; Röcken, Martin; Berneburg, Mark

    2008-01-01

    Polymorphic light eruption (PLE), with an overall prevalence of 10-20%, is mainly provoked by ultraviolet A (UVA) (320-400 nm) and to a lesser degree by UVB (280-320 nm). The most effective prophylaxis of PLE, application of UV protection clothing, is not feasible for all sun-exposed areas of the skin and UV-hardening is time-consuming and may be associated with side-effects. Most sunscreens protect predominantly against UVB and therefore fail to prevent PLE. The protection level of potent UVA-protective filters remains unresolved. This single-centre, open, placebo-controlled, intra-individual, comparative study, analysed the efficacy of a sunscreen of very high protection level against UVB and UVA, containing methylene bis-benzotriazolyl tetramethylbutylphenol (Tinosorb M), bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S) and butyl methoxydibenzoylmethane as UVA absorbing filters, in the prevention of PLE under standardized photodiagnostic conditions. After determination of the minimal erythema dose at day 0, photoprovocation was performed in 12 patients with a clinical history of PLE, on days 1, 2 and 3 with 100 J/cm2 UVA and variable doses of UVB, starting with the 1.5-fold minimal erythema dose of UVB. Prior to irradiation, placebo was applied to the right and sunscreen to the left dorsal forearm under COLIPA (European Cosmetic, Toiletry and Perfumery Association) conditions. In 10 patients PLE could be provoked at the placebo site, with positive reactions in 90% of the UVA, 40% of the UVB and 90% of the UVA/UVB irradiated fields. At the site with the active treatment none of these patients developed PLE. These data demonstrate that a sunscreen with effective filters against UVA and UVB can successfully prevent the development of PLE. Further studies are needed to examine whether regular application of sunscreen under everyday conditions, especially in doses less than the tested COLIPA-norm, could be an equivalent alternative to UV-hardening therapy.

  6. 2-Cysteine Peroxiredoxins and Thylakoid Ascorbate Peroxidase Create a Water-Water Cycle That Is Essential to Protect the Photosynthetic Apparatus under High Light Stress Conditions1

    PubMed Central

    Awad, Jasmin; Stotz, Henrik U.; Fekete, Agnes; Krischke, Markus; Engert, Cornelia; Havaux, Michel; Berger, Susanne; Mueller, Martin J.

    2015-01-01

    Different peroxidases, including 2-cysteine (2-Cys) peroxiredoxins (PRXs) and thylakoid ascorbate peroxidase (tAPX), have been proposed to be involved in the water-water cycle (WWC) and hydrogen peroxide (H2O2)-mediated signaling in plastids. We generated an Arabidopsis (Arabidopsis thaliana) double-mutant line deficient in the two plastid 2-Cys PRXs (2-Cys PRX A and B, 2cpa 2cpb) and a triple mutant deficient in 2-Cys PRXs and tAPX (2cpa 2cpb tapx). In contrast to wild-type and tapx single-knockout plants, 2cpa 2cpb double-knockout plants showed an impairment of photosynthetic efficiency and became photobleached under high light (HL) growth conditions. In addition, double-mutant plants also generated elevated levels of superoxide anion radicals, H2O2, and carbonylated proteins but lacked anthocyanin accumulation under HL stress conditions. Under HL conditions, 2-Cys PRXs seem to be essential in maintaining the WWC, whereas tAPX is dispensable. By comparison, this HL-sensitive phenotype was more severe in 2cpa 2cpb tapx triple-mutant plants, indicating that tAPX partially compensates for the loss of functional 2-Cys PRXs by mutation or inactivation by overoxidation. In response to HL, H2O2- and photooxidative stress-responsive marker genes were found to be dramatically up-regulated in 2cpa 2cpb tapx but not 2cpa 2cpb mutant plants, suggesting that HL-induced plastid to nucleus retrograde photooxidative stress signaling takes place after loss or inactivation of the WWC enzymes 2-Cys PRX A, 2-Cys PRX B, and tAPX. PMID:25667319

  7. A mutant of Chlamydomonas without LHCSR maintains high rates of photosynthesis, but has reduced cell division rates in sinusoidal light conditions.

    PubMed

    Cantrell, Michael; Peers, Graham

    2017-01-01

    The LHCSR protein belongs to the light harvesting complex family of pigment-binding proteins found in oxygenic photoautotrophs. Previous studies have shown that this complex is required for the rapid induction and relaxation of excess light energy dissipation in a wide range of eukaryotic algae and moss. The ability of cells to rapidly regulate light harvesting between this dissipation state and one favoring photochemistry is believed to be important for reducing oxidative stress and maintaining high photosynthetic efficiency in a rapidly changing light environment. We found that a mutant of Chlamydomonas reinhardtii lacking LHCSR, npq4lhcsr1, displays minimal photoinhibition of photosystem II and minimal inhibition of short term oxygen evolution when grown in constant excess light compared to a wild type strain. We also investigated the impact of no LHCSR during growth in a sinusoidal light regime, which mimics daily changes in photosynthetically active radiation. The absence of LHCSR correlated with a slight reduction in the quantum efficiency of photosystem II and a stimulation of the maximal rates of photosynthesis compared to wild type. However, there was no reduction in carbon accumulation during the day. Another novel finding was that npq4lhcsr1 cultures underwent fewer divisions at night, reducing the overall growth rate compared to the wild type. Our results show that the rapid regulation of light harvesting mediated by LHCSR is required for high growth rates, but it is not required for efficient carbon accumulation during the day in a sinusoidal light environment. This finding has direct implications for engineering strategies directed at increasing photosynthetic productivity in mass cultures.

  8. Heat shock transcriptional responses in an MC-Producing Cyanobacterium (Planktothrix agardhii) and its MC-deficient mutant under high light conditions.

    PubMed

    Tran, Thi Du Chi; Bernard, Cecile; Ammar, Myriam; Chaouch, Soraya; Comte, Katia

    2013-01-01

    Microcystins (MCs) are the most commonly-reported hepatotoxins produced by various cyanobacterial taxa in fresh waters to constitute a potential threat to human and animal health. The biological role of MCs in the producer organisms is not known, and it would be very useful to understand the driving force behind the toxin production. Recent studies have suggested that MCs may have a protective function in cells facing environmental stress. Following this starting premise, we speculate that under adverse conditions the expression of stress-related genes coding for Heat Shock Proteins (Hsp) might be different in an MC-producing strain and its MC-deficient mutant. We therefore used RT-qPCR to compare the expression of 13 hsp genes of an MC-producing strain of Planktothrix agardhii (CYA126/8) and its MC-deficient ΔmcyD mutant over different periods of exposure to high light stress (HL). Three reference genes (RGs) were selected from six candidates to normalize the RT-qPCR data. Of these three RGs (rsh, rpoD, and gltA), gltA is used here for the first time as an RG in prokaryotes. Under HL stress, five genes were found to be strongly up-regulated in both strains (htpG, dnaK, hspA, groES, and groEL). Unexpectedly, we found that the MC-producing wild type strain accumulated higher levels of htpG and dnaK transcripts in response to HL stress than the MC-deficient mutant. In addition, a significant increase in the mcyE transcript was detected in the mutant, suggesting that MCs are required under HL conditions. We discuss several possible roles of MCs in the response to HL stress through their possible involvement in the protective mechanisms of the cells.

  9. Tocopherols in Sunflower Seedlings under Light and Dark Conditions

    PubMed Central

    del Moral, Lidia; Pérez-Vich, Begoña

    2015-01-01

    The objective of this study was to evaluate the dynamics of tocopherols in cotyledons and radicles from sunflower seeds with high and low total tocopherol content, mainly in the α-tocopherol form, and from seeds with increased proportions of β-, γ-, and δ-tocopherol, both under dark and light conditions. Tocopherol content was measured every 24 h from 1 to 12 days after sowing. In all cases, the content of individual tocopherol forms in the cotyledons and radicles was reduced along the sampling period, which was more pronounced under light conditions. The presence of light had a slightly greater effect on α- and γ-tocopherol than on β- and δ-tocopherol. A marked light effect was also observed on total tocopherol content, with light promoting the reduction of tocopherol content in cotyledons and radicles. The study revealed only slight differences in the patterns of tocopherol losses in lines with different tocopherol profiles, both under dark and light conditions, which suggested that the partial replacement of α-tocopherol by other tocopherol forms had no great impact on the protection against oxidative damage in seedlings. PMID:26347898

  10. Tocopherols in Sunflower Seedlings under Light and Dark Conditions.

    PubMed

    del Moral, Lidia; Pérez-Vich, Begoña; Velasco, Leonardo

    2015-01-01

    The objective of this study was to evaluate the dynamics of tocopherols in cotyledons and radicles from sunflower seeds with high and low total tocopherol content, mainly in the α-tocopherol form, and from seeds with increased proportions of β-, γ-, and δ-tocopherol, both under dark and light conditions. Tocopherol content was measured every 24 h from 1 to 12 days after sowing. In all cases, the content of individual tocopherol forms in the cotyledons and radicles was reduced along the sampling period, which was more pronounced under light conditions. The presence of light had a slightly greater effect on α- and γ-tocopherol than on β- and δ-tocopherol. A marked light effect was also observed on total tocopherol content, with light promoting the reduction of tocopherol content in cotyledons and radicles. The study revealed only slight differences in the patterns of tocopherol losses in lines with different tocopherol profiles, both under dark and light conditions, which suggested that the partial replacement of α-tocopherol by other tocopherol forms had no great impact on the protection against oxidative damage in seedlings.

  11. High power cladding light strippers

    NASA Astrophysics Data System (ADS)

    Wetter, Alexandre; Faucher, Mathieu; Sévigny, Benoit

    2008-02-01

    The ability to strip cladding light from double clad fiber (DCF) fibers is required for many different reasons, one example is to strip unwanted cladding light in fiber lasers and amplifiers. When removing residual pump light for example, this light is characterized by a large numerical aperture distribution and can reach power levels into the hundreds of watts. By locally changing the numerical aperture (N.A.) of the light to be stripped, it is possible to achieve significant attenuation even for the low N.A. rays such as escaped core modes in the same device. In order to test the power-handling capability of this device, one hundred watts of pump and signal light is launched from a tapered fusedbundle (TFB) 6+1x1 combiner into a high power-cladding stripper. In this case, the fiber used in the cladding stripper and the output fiber of the TFB was a 20/400 0.06/0.46 N.A. double clad fiber. Attenuation of over 20dB in the cladding was measured without signal loss. By spreading out the heat load generated by the unwanted light that is stripped, the package remained safely below the maximum operating temperature internally and externally. This is achieved by uniformly stripping the energy along the length of the fiber within the stripper. Different adhesive and heat sinking techniques are used to achieve this uniform removal of the light. This suggests that these cladding strippers can be used to strip hundreds of watts of light in high power fiber lasers and amplifiers.

  12. High intensity portable fluorescent light

    NASA Technical Reports Server (NTRS)

    Kendall, F. B.

    1972-01-01

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

  13. High performance light emitting transistors

    NASA Astrophysics Data System (ADS)

    Namdas, Ebinazar B.; Ledochowitsch, Peter; Yuen, Jonathan D.; Moses, Daniel; Heeger, Alan J.

    2008-05-01

    Solution processed light emitting field-effect transistors (LEFETs) with peak brightness exceeding 2500cd/m2 and external quantum efficiency of 0.15% are demonstrated. The devices utilized a bilayer film comprising a hole transporting polymer, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] thiophene) and a light emitting polymer, Super Yellow, a polyphenylenevinylene derivative. The LEFETs were fabricated in the bottom gate architecture with top-contact Ca /Ag as source/drain electrodes. Light emission was controlled by the gate voltage which controls the hole current. These results indicate that high brightness LEFETs can be made by using the bilayer film (hole transporting layer and a light emitting polymer).

  14. Long-duration animal tracking in difficult lighting conditions

    PubMed Central

    Stern, Ulrich; Zhu, Edward Y.; He, Ruo; Yang, Chung-Hui

    2015-01-01

    High-throughput analysis of animal behavior requires software to analyze videos. Such software typically depends on the experiments’ being performed in good lighting conditions, but this ideal is difficult or impossible to achieve for certain classes of experiments. Here, we describe techniques that allow long-duration positional tracking in difficult lighting conditions with strong shadows or recurring “on”/“off” changes in lighting. The latter condition will likely become increasingly common, e.g., for Drosophila due to the advent of red-shifted channelrhodopsins. The techniques enabled tracking with good accuracy in three types of experiments with difficult lighting conditions in our lab. Our technique handling shadows relies on single-animal tracking and on shadows’ and flies’ being accurately distinguishable by distance to the center of the arena (or a similar geometric rule); the other techniques should be broadly applicable. We implemented the techniques as extensions of the widely-used tracking software Ctrax; however, they are relatively simple, not specific to Drosophila, and could be added to other trackers as well. PMID:26130571

  15. Long-duration animal tracking in difficult lighting conditions.

    PubMed

    Stern, Ulrich; Zhu, Edward Y; He, Ruo; Yang, Chung-Hui

    2015-07-01

    High-throughput analysis of animal behavior requires software to analyze videos. Such software typically depends on the experiments' being performed in good lighting conditions, but this ideal is difficult or impossible to achieve for certain classes of experiments. Here, we describe techniques that allow long-duration positional tracking in difficult lighting conditions with strong shadows or recurring "on"/"off" changes in lighting. The latter condition will likely become increasingly common, e.g., for Drosophila due to the advent of red-shifted channel rhodopsins. The techniques enabled tracking with good accuracy in three types of experiments with difficult lighting conditions in our lab. Our technique handling shadows relies on single-animal tracking and on shadows' and flies' being accurately distinguishable by distance to the center of the arena (or a similar geometric rule); the other techniques should be broadly applicable. We implemented the techniques as extensions of the widely-used tracking software Ctrax; however, they are relatively simple, not specific to Drosophila, and could be added to other trackers as well.

  16. Long-duration animal tracking in difficult lighting conditions

    NASA Astrophysics Data System (ADS)

    Stern, Ulrich; Zhu, Edward Y.; He, Ruo; Yang, Chung-Hui

    2015-07-01

    High-throughput analysis of animal behavior requires software to analyze videos. Such software typically depends on the experiments’ being performed in good lighting conditions, but this ideal is difficult or impossible to achieve for certain classes of experiments. Here, we describe techniques that allow long-duration positional tracking in difficult lighting conditions with strong shadows or recurring “on”/“off” changes in lighting. The latter condition will likely become increasingly common, e.g., for Drosophila due to the advent of red-shifted channelrhodopsins. The techniques enabled tracking with good accuracy in three types of experiments with difficult lighting conditions in our lab. Our technique handling shadows relies on single-animal tracking and on shadows’ and flies’ being accurately distinguishable by distance to the center of the arena (or a similar geometric rule); the other techniques should be broadly applicable. We implemented the techniques as extensions of the widely-used tracking software Ctrax; however, they are relatively simple, not specific to Drosophila, and could be added to other trackers as well.

  17. Suboptimal Light Conditions Influence Source-Sink Metabolism during Flowering.

    PubMed

    Christiaens, Annelies; De Keyser, Ellen; Pauwels, Els; De Riek, Jan; Gobin, Bruno; Van Labeke, Marie-Christine

    2016-01-01

    Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7°C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed. Glucose and fructose concentrations and invertase activity increased in petals during flowering, while sucrose decreased. In suboptimal light conditions RsSUS expression in leaves increased as compared to optimal light conditions, indicating that plants in suboptimal light conditions have a strong demand for carbohydrates. However, carbohydrates in leaves were markedly lower in suboptimal light conditions compared to optimal light conditions. This resulted in poor flowering of plants in suboptimal light conditions. Post-production flowering relied on the stored leaf carbon, which could be accumulated under optimal light conditions in the greenhouse. These results show that flower opening in azalea relies on carbohydrates imported from leaves and is source-limiting under suboptimal light conditions.

  18. Suboptimal Light Conditions Influence Source-Sink Metabolism during Flowering

    PubMed Central

    Christiaens, Annelies; De Keyser, Ellen; Pauwels, Els; De Riek, Jan; Gobin, Bruno; Van Labeke, Marie-Christine

    2016-01-01

    Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7°C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed. Glucose and fructose concentrations and invertase activity increased in petals during flowering, while sucrose decreased. In suboptimal light conditions RsSUS expression in leaves increased as compared to optimal light conditions, indicating that plants in suboptimal light conditions have a strong demand for carbohydrates. However, carbohydrates in leaves were markedly lower in suboptimal light conditions compared to optimal light conditions. This resulted in poor flowering of plants in suboptimal light conditions. Post-production flowering relied on the stored leaf carbon, which could be accumulated under optimal light conditions in the greenhouse. These results show that flower opening in azalea relies on carbohydrates imported from leaves and is source-limiting under suboptimal light conditions. PMID:26973689

  19. Strategy Guideline: High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    The Strategy Guideline: High Performance Residential Lighting has been developed to provide a tool for the understanding and application of high performance lighting in the home. The high performance lighting strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner's expectations for high quality lighting.

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

    SciTech Connect

    McCullough, Jeffrey J.; Gordon, Kelly L.

    2002-08-30

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

  1. High-bay Lighting Energy Conservation Measures

    SciTech Connect

    Ian Metzger, Jesse Dean

    2010-12-31

    This software requires inputs of simple high-bay lighting system inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: 1000 Watt to 750 Watt High-pressure Sodium lighting retrofit, 400 Watt to 360 Watt High Pressure Sodium lighting retrofit, High Intensity Discharge to T5 lighting retrofit, High Intensity Discharge to T8 lighting retrofit, and Daylighting. This tool calculates energy savings, demand reduction, cost savings, building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  2. Supervised retinal biometrics in different lighting conditions.

    PubMed

    Azemin, Mohd Zulfaezal Che; Kumar, Dinesh K; Sugavaneswaran, Lakshmi; Krishnan, Sridhar

    2011-01-01

    Retinal image has been considered for number of health and biometrics applications. However, the reliability of these has not been investigated thoroughly. The variation observed in retina scans taken at different times is attributable to differences in illumination and positioning of the camera. It causes some missing bifurcations and crossovers from the retinal vessels. Exhaustive selection of optimal parameters is needed to construct the best similarity metrics equation to overcome the incomplete landmarks. In this paper, we extracted multiple features from the retina scans and employs supervised classification to overcome the shortcomings of the current techniques. The experimental results of 60 retina scans with different lightning conditions demonstrate the efficacy of this technique. The results were compared with the existing methods.

  3. Differential regulation of two sucrose transporters by defoliation and light conditions in perennial ryegrass.

    PubMed

    Furet, Pierre-Maxime; Berthier, Alexandre; Decau, Marie-Laure; Morvan-Bertrand, Annette; Prud'homme, Marie-Pascale; Noiraud-Romy, Nathalie; Meuriot, Frédéric

    2012-12-01

    Sucrose transport between source and sink tissues is supposed to be a key-step for an efficient regrowth of perennial rye-grass after defoliation and might be altered by light conditions. We assessed the effect of different light regimes (high vs low light applied before or after defoliation) on growth, fructans and sucrose mobilization, as well as on sucrose transporter expression during 14 days of regrowth. Our results reported that defoliation led to a mobilization of C reserves (first sucrose and then fructans), which was parallel to an induction of LpSUT1 sucrose transporter expression in source and sink tissues (i.e. leaf sheaths and elongating leaf bases, respectively) irrespective to light conditions. Light regime (high or low light) had little effects on regrowth and on C reserves mobilization during the first 48 h of regrowth after defoliation. Thereafter, low light conditions, delaying the recovery of photosynthetic capacities, had a negative effect on C reserves re-accumulation (especially sucrose). Surprisingly, high light did not enhance sucrose transporter expression. Indeed, while light conditions had no effect on LpSUT1 expression, LpSUT2 transcripts levels were enhanced for low light grown plants. These results indicate that two sucrose transporter currently identified in Lolium perenne L. are differentially regulated by light and sucrose.

  4. Strategy Guideline. High Performance Residential Lighting

    SciTech Connect

    Holton, J.

    2012-02-01

    This report has been developed to provide a tool for the understanding and application of high performance lighting in the home. The strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner’s expectations for high quality lighting.

  5. 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.

  6. 78 FR 27033 - Safety Zone; High Water Conditions; Illinois River

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; High Water Conditions; Illinois River... intended to place restrictions on vessels due to current extreme high-water conditions. This safety zone is... History and Information On April 18, 2013, in light of dangerously high water conditions, the Coast...

  7. High-resolution light microscopy of nanoforms

    NASA Astrophysics Data System (ADS)

    Vodyanoy, Vitaly; Pustovyy, Oleg; Vainrub, Arnold

    2007-09-01

    We developed a high resolution light imaging system. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects are clearly visible on a calibrated microscope test slide (Vainrub et al., Optics Letters, 2006, 31, 2855). The two-point resolution increase results from a known narrowing of the central diffraction peak for the annular aperture. Better visibility and advanced contrast of the smallest features in the image are due to enhancement of high spatial frequencies in the optical transfer function. The imaging system is portable, low energy, and battery operated. It has been adapted to use in both transmitting and reflecting light. It is particularly applicable for motile nanoform systems where structure and functions can be depicted in real time. We have isolated micrometer and submicrometer particles, termed proteons, from human and animal blood. Proteons form by reversible seeded aggregation of proteins around proteon nucleating centers (PNCs). PNCs are comprised of 1-2nm metallic nanoclusters containing 40-300 atoms. Proteons are capable of spontaneous assembling into higher nanoform systems assuming structure of complicated topology. The arrangement of complex proteon system mimics the structure of a small biological cell. It has structures that imitate membrane and nucleolus or nuclei. Some of these nanoforms are motile. They interact and divide. Complex nanoform systems can spontaneously reduce to simple proteons. The physical properties of these nanoforms could shed some light on the properties of early life forms or forms at extreme conditions.

  8. Light conditions affect the roll-induced vestibuloocular reflex in Xenopus laevis tadpoles

    NASA Astrophysics Data System (ADS)

    El-Yamany, Nabil A.

    2008-12-01

    In Xenopus laevis tadpoles, effects of asymmetrical light conditions on the roll-induced vestibuloocular reflex (rVOR) were tested for the developmental period between stage 47 and 49. For comparison, the rVOR was tested in dim- and high-symmetrical light environments. Test parameters were the rVOR gain and rVOR amplitude. Under all light conditions, the rVOR increased from tadpole stage 47 to 49. For all stages, the asymmetrical light field induced the strongest response, the dim light field the weakest one. The response for the left and right eye was identical, even if the tadpoles were tested under asymmetrical light conditions. The experiments can be considered as hints (1) for an age-dependent light sensitivity of vestibular neurons, and (2) for the existence of control systems for coordinated eye movements that has its origin in the proprioceptors of the extraocular eye muscles.

  9. Functional proteomics of light-harvesting complex proteins under varying light-conditions in diatoms.

    PubMed

    Büchel, Claudia; Wilhelm, Christian; Wagner, Volker; Mittag, Maria

    2017-10-01

    Comparative proteome analysis of subcellular compartments like thylakoid membranes and their associated supercomplexes can deliver important in-vivo information on the molecular basis of physiological functions which go far beyond to that what can be learnt from transcriptional-based gene expression studies. For instance, the finding that light intensity influences mainly the relative stoichiometry of subunits could be obtained only by high resolution proteome analysis. The high sensitivity of LC-ESI-MS/MS based proteome analysis allows the determination of proteins in very small subfractions along with their non-labeled semi quantitative analysis. This provides insights in the protein-protein interactions of supercomplexes that are the operative units in intact cells. Here, we have focused on functional proteome approaches for the identification of microalgal light-harvesting complex proteins in chloroplasts and the eyespot in general and in detail for those of diatoms that are exposed to varying light conditions. Copyright © 2017 Elsevier GmbH. All rights reserved.

  10. Antibacterial effect and mechanism of high-intensity 405 ± 5 nm light emitting diode on Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus under refrigerated condition.

    PubMed

    Kim, Min-Jeong; Mikš-Krajnik, Marta; Kumar, Amit; Ghate, Vinayak; Yuk, Hyun-Gyun

    2015-12-01

    This study investigated the antibacterial effect of 405 ± 5 nm light emitting diode (LED) on Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus, and examined its antibacterial mechanism by determining the bacterial membrane and DNA damages. A 405 ± 5 nm LED illuminated the Gram-positive pathogens until 486 J/cm(2) at 4 °C. Weibull model was used to calculate reliable life (tR) to compare bacterial sensitivities to LED illumination. The membrane damage was determined by NaCl and LIVE/DEAD® assay, while comet assay and DNA ladder analysis were conducted to determine DNA degradation. The illumination resulted in 1.9, 2.1, and 1.0 log reductions for B. cereus, L. monocytogenes, and S. aureus at 486 J/cm(2), respectively. The comparison of tR values revealed that L. monocytogenes was identified as the most susceptible strain to LED illumination. The percentage of the bacterial sensitivity to NaCl remarkably increased in LED-illuminated cells compared to non-illuminated cells. Moreover, loss of membrane integrity was confirmed for LED-illuminated cells by LIVE/DEAD® assay, whereas no DNA breakage was indicated by comet assay and DNA ladder analysis. Thus, these findings suggest that the antibacterial effect of 405 ± 5 nm LED illumination on these pathogens might be due to physical damage to bacterial membrane rather than DNA degradation.

  11. Disposable indicators for monitoring lighting conditions in museums.

    PubMed

    Bacci, Mauro; Cucci, Costanza; Dupont, Anne-Laurence; Lavédrine, Bertrand; Picollo, Marcello; Porcinai, Simone

    2003-12-15

    Photoinduced alterations of light-sensitive artifacts represent one of the main problems that conservators and curators have to face for environmental control in museums and galleries. Therefore, increasing attention has been recently devoted to developing strategies of indoor light monitoring, especially aimed at minimizing the cumulated light exposure for the objects on exhibit. In this work a prototype of a light dosimeter, constituted by a photosensitive dyes/polymer mixture applied on a paper substrate, is presented. This indicator, specially designed for a preventive assessment of the risk of damage for highly light-sensitive objects, undergoes a progressive color variation as its exposure to the light increases. Different, easily distinguishable color steps are exhibited depending on the light dose received, so that the dosimeter can be used straightforwardly to have a first, instrumentation-free estimation of the total light exposure. A reflectance spectroscopy study in the 350-860 nm range was carried out on prototype dosimeters exposed to light emitted from a tungsten-halogen lamp to investigate the response of the dosimeter to the light and to study the fading mechanism. Two different approaches were evaluated for the calibration of the prototype: colorimetry and principal component analysis of the reflectance spectra. The usefulness of the two methods in providing a quantitative indication of the light dose received was evaluated.

  12. [Comparison of light response models of photosynthesis in Nelumbo nucifera leaves under different light conditions].

    PubMed

    Leng, Han-Bing; Qin, Jun; Ye, King; Feng, Shu-Cheng; Gao, Kai

    2014-10-01

    The light responses of Nelumbo nucifera 'Boli Furen', a local N. nucifera species was investigated under full light and 50% shading conditions in Shanghai. The net photosynthetic rate-light response curves of N. nucifera leaves were fitted and analyzed through four light response models to identify the best-fit models of different light conditions and explore the adaptability of N. nucifera to shading environment. The results showed that the sequence of fitting effect of the four light response models was in descending order of modified rectangular hyperbola model > exponential model > non-rectangular hyperbola model > rectangular hyperbola model. The latter three models had no extreme values, and could not directly and accurately provide values of light saturation point (LSP) and maximum net photosynthetic rate (Pn max). In contrast, the modified rectangular hyperbola model showed the best fit for LSP, Pn max, dark respiration rate (Rd) and LCP resulting in the minimum relative errors between the measured and fitted values. Light response parameters of N. nucifera declined with the decreasing light. There were no significant differences between full light and shade treatments except for Rd. It was indicated that N. nucifera had good photosynthetic adaptive response and adjustment to weak light to maintain normal growth.

  13. Transitioning to Low-GWP Alternatives in Residential and Light Commercial Air Conditioning

    EPA Pesticide Factsheets

    This fact sheet provides current information on low global warming potential (GWP) alternatives for new equipment in residential and light commercial air conditioning (AC), in lieu of high-GWP hydrofluorocarbons (HFCs).

  14. Boundary conditions on faster-than-light transportation systems

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.; Knowles, H. B.

    1993-01-01

    In order to be consistent with current physical theories, any proposal of a faster-than light (FTL) transportation system must satisfy several critical conditions. It must predict the mass, space, and time dimensional changes predicted by relativity physics when velocity falls below the speed of light. It must also not violate causality, and remain consistent with quantum physics in the limit of microscopic systems. It is also essential that the proposal conserve energy.

  15. Boundary conditions on faster-than-light transportation systems

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.; Knowles, H. B.

    1993-01-01

    In order to be consistent with current physical theories, any proposal of a faster-than light (FTL) transportation system must satisfy several critical conditions. It must predict the mass, space, and time dimensional changes predicted by relativity physics when velocity falls below the speed of light. It must also not violate causality, and remain consistent with quantum physics in the limit of microscopic systems. It is also essential that the proposal conserve energy.

  16. Exposure to high- and low-light conditions in an open-field test of anxiety increases c-Fos expression in specific subdivisions of the rat basolateral amygdaloid complex.

    PubMed

    Hale, Matthew W; Bouwknecht, J Adriaan; Spiga, Francesca; Shekhar, Anantha; Lowry, Christopher A

    2006-12-11

    Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of forebrain structures including the basolateral amygdaloid complex (basolateral amygdala). Despite a wealth of research examining the role of the basolateral amygdala in anxiety-related behaviors and anxiety states, the specific subdivisions of the basolateral amygdala that are involved in responses to anxiogenic stimuli have not been examined. In this study, we investigated the effects of exposure to a novel open-field environment, with either low- or high-levels of illumination, on expression of the protein product of the immediate-early gene c-Fos in subdivisions of the rat basolateral amygdala. The subdivisions studied included the lateral, ventrolateral and ventromedial parts of the lateral amygdaloid nucleus, the anterior, posterior and ventral parts of the basolateral amygdaloid nucleus and the anterior and posterior part of the basomedial amygdaloid nucleus. Small increases in the number of c-Fos-immunoreactive cells were observed in several, but not all, of the subdivisions of the basolateral amygdala studied following exposure of rats to either the high- or low-light conditions, compared to home cage or handled control groups. Open-field exposure in both the high- and low-light conditions resulted in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus compared to either home cage or handled control groups. These findings point toward anatomical and functional heterogeneity within the basolateral amygdaloid complex and an important role of the anterior part of the basolateral amygdaloid nucleus in the neural mechanisms underlying physiological or behavioral responses to this anxiety-related stimulus.

  17. Gene expression by Onoclea Sensibilis gametophytes under different light conditions

    SciTech Connect

    Chansa-ngavej, K.; Raghavan, V.

    1987-04-01

    Gametophytes of the fern Onoclea sensibilis grow as filaments in red light or in complete darkness by divisions perpendicular to the long axis of the cell. When transferred to blue light the gametophytes exhibit a plate-like structure as a result of both transverse and longitudinal cell divisions. Both 1-D and 2-D SDS-polyacrylamide gel electrophoresis revealed quantitative and qualitative differences in the polypeptide patterns of the gametophytes grown in red and blue light regimes and in complete darkness. NAD/sup +/-Glyceraldehyde-3-phosphate dehydrogenase activity was found to increase sharply within 4 hours of transfer of the gametophytes from red light to blue light and to complete darkness. /sup 3/H-Leucine was incorporated at a higher rate into proteins of gametophytes after 2 hours of transfer from red light to blue light and to complete darkness. These results seem to indicate possible involvement of differential protein synthesis and hence differential gene expression during growth of gametophytes under different light conditions.

  18. [Effects of different water, fertility, and light conditions on allelopathic traits of rice].

    PubMed

    Hu, Fei; Kong, Chuihua; Chen, Xonghui; Zhang, Zhaoxian

    2003-12-01

    The allelochemicals and allelopathic potentials of rice (Huahang No. 1) were investigated under different water, fertility, and light conditions with pot culture. The results showed that the allelopathic potential of Huahang No. 1 was stronger at high levels of water and fertility, but its specific allelochemicals contents had no significant variation at both levels. The numbers of the total secondary metabolites and the contents of some anti-pathogenic chemicals were increased at low level of water or fertility. Furthermore, the contents of specific allelochemicals in Huahang No. 1 were lower under strong light than under weak light condition. Similarity, the allelopathic potential decreased, and the contents of some anti-pathogenic chemicals maintained unchanged under weak light condition. No matter what levels of water, fertility or light conditions were, the allelopathic potential of Huahang No. 1 on associated weeds was weaker than that on non-associated ones.

  19. Efficient color face detection algorithm under different lighting conditions

    NASA Astrophysics Data System (ADS)

    Chow, Tze-Yin; Lam, Kin-Man; Wong, Kwok-Wai

    2006-01-01

    We present an efficient and reliable algorithm to detect human faces in an image under different lighting conditions. In our algorithm, skin-colored pixels are identified using a region-based approach, which can provide more reliable skin color segmentation under various lighting conditions. In addition, to compensate for extreme lighting conditions, a color compensation scheme is proposed, and the distributions of the skin-color components under various illuminations are modeled by means of the maximum-likelihood method. With the skin-color regions detected, a ratio method is proposed to determine the possible positions of the eyes in the image. Two eye candidates form a possible face region, which is then verified as a face or not by means of a two-stage procedure with an eigenmask. Finally, the face boundary region of a face candidate is further verified by a probabilistic approach to reduce the chance of false alarms. Experimental results based on the HHI MPEG-7 face database, the AR face database, and the CMU pose, illumination, and expression (PIE) database show that this face detection algorithm is efficient and reliable under different lighting conditions and facial expressions.

  20. High-fidelity teleportation between light and atoms

    SciTech Connect

    Hammerer, K.; Polzik, E. S.; Cirac, J. I.

    2006-12-15

    We show how high-fidelity quantum teleportation of light to atoms can be achieved in the same setup as was used in the recent experiment [J. Sherson et al., Nature 443, 557, 2006], where such an interspecies quantum state transfer was demonstrated for the first time. Our improved protocol takes advantage of the rich multimode entangled structure of the state of atoms and scattered light and requires simple postprocessing of homodyne detection signals and squeezed light in order to achieve fidelities up to 90% (85%) for teleportation of coherent (qubit) states under realistic experimental conditions. The remaining limitation is due to atomic decoherence and light losses.

  1. Acclimation strategy of Rhodopseudomonas palustris to high light irradiance.

    PubMed

    Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

    2017-04-01

    The ability of Rhodopseudomonas palustris cells to rapidly acclimate to high light irradiance is an essential issue when cells are grown under sunlight. The aim of this study was to investigate the photo-acclimation process in Rhodopseudomonas palustris 42OL under different culturing conditions: (i) anaerobic (AnG), (ii) aerobic (AG), and (iii) under H2-producing (HP) conditions both at low (LL) and high light (HL) irradiances. The results obtained clearly showed that the photosynthetic unit was significantly affected by the light irradiance at which Rp. palustris 42OL was grown. The synthesis of carotenoids was affected by both illumination and culturing conditions. At LL, lycopene was the main carotenoid synthetized under all conditions tested, while at HL under HP conditions, it resulted the predominant carotenoid. Oppositely, under AnG and AG at HL, rhodovibrin was the major carotenoid detected. The increase in light intensity produced a deeper variation in light-harvesting complexes (LHC) ratio. These findings are important for understanding the ecological distribution of PNSB in natural environments, mostly characterized by high light intensities, and for its growth outdoors.

  2. Intermittent exposure to bright light in field conditions.

    PubMed

    Boivin, Diane B; James, Francine O

    2004-03-01

    The Interactive Neurobehavioral Model integrates Kronauer's and Jewett's latest mathematical model of the resetting effect of light on the human circadian pacemaker. This model is based on several lines of experimental evidence and considers the endogenous circadian pacemaker as a complex oscillatory system that responds dynamically to the resetting effect of light. This model can help us understand the results of an experiment using intermittent bright light exposure in the workplace environment. Intermittent exposure to bright light was effectively used as part of an intervention to promote circadian re-entrainment of a group of nurses to their permanent night work schedule. Regular exposure to lower light levels and darkness also provided a significant phase delay of endogenous circadian rhythms, although the adaptation was incomplete in this group of workers. These last results are consistent with the intensity-dependent component of the model. The development of better tools to measure retinal exposure to light throughout the 24-h day is required to adequately test modeling predictions under field conditions.

  3. Lighting conditions affect testosterone feedback sensitivity in castrated rats.

    PubMed

    Porkka-Heiskanen, T; Laakso, M L; Stenberg, D; Johansson, G; Peder, M

    1989-01-01

    It has been shown in the Syrian hamster that a short photoperiod sensitizes the hypothalamo-hypophyseal axis of castrated animals to the negative feedback effect of testosterone. There is some evidence that even the reproductive system of the rat, which is generally considered not to be very sensitive to light, can respond to changes in illumination. Therefore, we found it of interest to examine whether alterations in lighting conditions produce changes of sensitivity in the negative feedback effect of testosterone in the rat. We kept intact, castrated, and castrated testosterone-treated animals either in periodic (L:D 12:12) or constant light for 7 days starting 4 weeks after castration. In all 3 testosterone-injected groups, serum luteinizing hormone (LH) was lower in constant than in periodic light. Exogenous testosterone did not decrease the castration-induced elevations of pituitary LH and follicle-stimulating hormone (FSH). On the contrary, testosterone increased the pituitary contents of LH and FSH, especially in constant light. We conclude that, in constant light, the hypothalamo-hypophyseal axis of the castrated rat becomes more sensitive to the negative feedback action of testosterone.

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

    PubMed

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

    2009-07-01

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

  5. High-aperture cryogenic light microscopy.

    PubMed

    Le Gros, M A; McDermott, G; Uchida, M; Knoechel, C G; Larabell, C A

    2009-07-01

    We report here the development of instruments and protocols for carrying out high numerical aperture immersion light microscopy on cryogenic specimens. Imaging by this modality greatly increases the lifetimes of fluorescence probes, including those commonly used for protein localization studies, while retaining the ability to image the specimen with high fidelity and spatial resolution. The novel use of a cryogenic immersion fluid also minimizes the refractive index mismatch between the sample and lens, leading to a more efficient coupling of the light from the sample to the image forming system. This enhancement is applicable to both fluorescence and transmitted light microscopy techniques. The design concepts used for the cryogenic microscope can be applied to virtually any existing light-based microscopy technique. This prospect is particularly exciting in the context of 'super-resolution' techniques, where enhanced fluorescence lifetime probes are especially useful. Thus, using this new modality it is now possible to observe dynamic events in a live cell, and then rapidly vitrify the specimen at a specific time point prior to carrying out high-resolution imaging. The techniques described can be used in conjunction with other imaging modalities in correlated studies. We have also developed instrumentation to perform cryo-light imaging together with soft X-ray tomography on the same cryo-fixed specimen as a means of carrying out high content, quantifiable correlated imaging analyses. These methods are equally applicable to correlated light and electron microscopy of frozen biological objects.

  6. High-aperture cryogenic light microscopy

    PubMed Central

    LE GROS, M.A.; McDERMOTT, G.; UCHIDA, M.; KNOECHEL, C.G.; LARABELL, C.A.

    2012-01-01

    Summary We report here the development of instruments and protocols for carrying out high numerical aperture immersion light microscopy on cryogenic specimens. Imaging by this modality greatly increases the lifetimes of fluorescence probes, including those commonly used for protein localization studies, while retaining the ability to image the specimen with high fidelity and spatial resolution. The novel use of a cryogenic immersion fluid also minimizes the refractive index mismatch between the sample and lens, leading to a more efficient coupling of the light from the sample to the image forming system. This enhancement is applicable to both fluorescence and transmitted light microscopy techniques. The design concepts used for the cryogenic microscope can be applied to virtually any existing light-based microscopy technique. This prospect is particularly exciting in the context of ‘super-resolution’ techniques, where enhanced fluorescence lifetime probes are especially useful. Thus, using this new modality it is now possible to observe dynamic events in a live cell, and then rapidly vitrify the specimen at a specific time point prior to carrying out high-resolution imaging. The techniques described can be used in conjunction with other imaging modalities in correlated studies. We have also developed instrumentation to perform cryo-light imaging together with soft X-ray tomography on the same cryo-fixed specimen as a means of carrying out high content, quantifiable correlated imaging analyses. These methods are equally applicable to correlated light and electron microscopy of frozen biological objects. PMID:19566622

  7. Photoacclimation supports environmental tolerance of a sponge to turbid low-light conditions

    NASA Astrophysics Data System (ADS)

    Biggerstaff, A.; Smith, D. J.; Jompa, J.; Bell, J. J.

    2015-12-01

    Changes to coral reefs are occurring worldwide, often resulting in declining environmental quality which can be in the form of higher sedimentation rates and increased turbidity. While environmental acclimation to turbid and low-light conditions has been extensively studied in corals, far less is known about other phototrophic reef invertebrates. The photosynthetic cyanobacteria containing sponge Lamellodysidea herbacea is one of the most abundant sponges in the Wakatobi Marine National Park (WMNP, Indonesia), and its abundance is greatest at highly disturbed, turbid sites. This study investigated photoacclimation of L. herbacea symbionts to turbid reef sites using in situ PAM fluorometry combined with shading and transplant experiments at environmental extremes of light availability for this species. We found in situ photoacclimation of L. herbacea to both shallow, clear, high-light environments and deep, turbid, low-light environments. Shading experiments provide some evidence that L. herbacea are dependent on nutrition from their photosymbionts as significant tissue loss was seen in shaded sponges. Symbionts within surviving shaded tissue showed evidence of photoacclimation. Lamellodysidea herbacea transplanted from high- to low-light conditions appeared to have photoacclimated within 5 d with no significant effect of the lowered light level on survival. This ability of L. herbacea to photoacclimate to rapid and extreme changes in light availability may be one of the factors contributing to their survival on more turbid reef sites in the WMNP. Our study highlights the ability of some sponge species to acclimate to changes in light levels as a result of increased turbidity.

  8. Identification of traffic accident risk-prone areas under low-light conditions

    NASA Astrophysics Data System (ADS)

    Ivan, K.; Haidu, I.; Benedek, J.; Ciobanu, S. M.

    2015-09-01

    Besides other non-behavioural factors, low-light conditions significantly influence the frequency of traffic accidents in an urban environment. This paper intends to identify the impact of low-light conditions on traffic accidents in the city of Cluj-Napoca, Romania. The dependence degree between light and the number of traffic accidents was analysed using the Pearson correlation, and the relation between the spatial distribution of traffic accidents and the light conditions was determined by the frequency ratio model. The vulnerable areas within the city were identified based on the calculation of the injury rate for the 0.5 km2 areas uniformly distributed within the study area. The results show a strong linear correlation between the low-light conditions and the number of traffic accidents in terms of three seasonal variations and a high probability of traffic accident occurrence under the above-mentioned conditions at the city entrances/exits, which represent vulnerable areas within the study area. Knowing the linear dependence and the spatial relation between the low light and the number of traffic accidents, as well as the consequences induced by their occurrence, enabled us to identify the areas of high traffic accident risk in Cluj-Napoca.

  9. Identification of traffic accident risk-prone areas under low lighting conditions

    NASA Astrophysics Data System (ADS)

    Ivan, K.; Haidu, I.; Benedek, J.; Ciobanu, S. M.

    2015-02-01

    Besides other non-behavioural factors, the low lighting conditions significantly influence the frequency of the traffic accidents in the urban environment. This paper intends to identify the impact of low lighting conditions on the traffic accidents in the city of Cluj-Napoca. The dependence degree between lighting and the number of traffic accidents was analyzed by the Pearson's correlation and the relation between the spatial distribution of traffic accidents and the lighting conditions was determined by the frequency ratio model. The vulnerable areas within the city were identified based on the calculation of the injured persons rate for the 0.5 km2 equally-sized areas uniformly distributed within the study area. The results have shown a strong linear dependence between the low lighting conditions and the number of traffic accidents in terms of three seasonal variations and a high probability of traffic accidents occurrence under the above-mentioned conditions, at the city entrances-exits, which represent also vulnerable areas within the study area. Knowing the linear dependence and the spatial relation between the low lighting and the number of traffic accidents, as well as the consequences induced by their occurrence enabled us to identify the high traffic accident risk areas in the city of Cluj-Napoca.

  10. Highly efficient white OLEDs for lighting applications

    NASA Astrophysics Data System (ADS)

    Murano, Sven; Burghart, Markus; Birnstock, Jan; Wellmann, Philipp; Vehse, Martin; Werner, Ansgar; Canzler, Tobias; Stübinger, Thomas; He, Gufeng; Pfeiffer, Martin; Boerner, Herbert

    2005-10-01

    The use of organic light-emitting diodes (OLEDs) for large area general lighting purposes is gaining increasing interest during the recent years. Especially small molecule based OLEDs have already shown their potential for future applications. For white light emission OLEDs, power efficiencies exceeding that of incandescent bulbs could already be demonstrated, however additional improvements are needed to further mature the technology allowing for commercial applications as general purpose illuminating sources. Ultimately the efficiencies of fluorescent tubes should be reached or even excelled, a goal which could already be achieved in the past for green OLEDs.1 In this publication the authors will present highly efficient white OLEDs based on an intentional doping of the charge carrier transport layers and the usage of different state of the art emission principles. This presentation will compare white PIN-OLEDs based on phosphorescent emitters, fluorescent emitters and stacked OLEDs. It will be demonstrated that the reduction of the operating voltage by the use of intentionally doped transport layers leads to very high power efficiencies for white OLEDs, demonstrating power efficiencies of well above 20 lm/W @ 1000 cd/m2. The color rendering properties of the emitted light is very high and CRIs between 85 and 95 are achieved, therefore the requirements for standard applications in the field of lighting applications could be clearly fulfilled. The color coordinates of the light emission can be tuned within a wide range through the implementation of minor structural changes.

  11. High Pressure Microwave Powered UV Light Sources

    NASA Astrophysics Data System (ADS)

    Cekic, M.; Frank, J. D.; Popovic, S.; Wood, C. H.

    1997-10-01

    Industrial microwave powered (*electrodeless*) light sources have been limited to quiescent pressures of 300 Torr of buffer gas and metal- halide fills. Recently developed multi-atmospheric electronegative bu lb fills (noble gas-halide excimers, metal halide) require electric field s for ionization that are often large multiples of the breakdown voltage for air. For these fills an auxiliary ignition system is necessary. The most successful scheme utilizes a high voltage pulse power supply and a novel field emission source. Acting together they create localized condition of pressure reduction and high free electron density. This allows the normal microwave fields to drive this small region into avalanche, ignite the bulb, and heat the plasma to it's operating poin t Standard diagnostic techniques of high density discharges are inapplicable to the excimer bulbs, because of the ionic molecular exci ted state structure and absence of self-absorption. The method for temperature determination is based on the equilibrium population of certain vibrational levels of excimer ionic excited states. Electron d ensity was determined from the measurements of Stark profiles of H_β radiation from a small amount of hydrogen mixed with noble gas and halogens. At the present time, high pressure (Te 0.5eV, ne 3 x 10^17 cm-3) production bulbs produce over 900W of radiation in a 30nm band, centered at 30nm. Similarly, these prototypes when loaded with metal-halide bulb fills produce 1 kW of radiation in 30nm wide bands, centered about the wavelength of interest.

  12. Muscular pre-conditioning using light-emitting diode therapy (LEDT) for high-intensity exercise: a randomized double-blind placebo-controlled trial with a single elite runner.

    PubMed

    Ferraresi, Cleber; Beltrame, Thomas; Fabrizzi, Fernando; do Nascimento, Eduardo Sanches Pereira; Karsten, Marlus; Francisco, Cristina de Oliveira; Borghi-Silva, Audrey; Catai, Aparecida Maria; Cardoso, Daniel Rodrigues; Ferreira, Antonio Gilberto; Hamblin, Michael R; Bagnato, Vanderlei Salvador; Parizotto, Nivaldo Antonio

    2015-07-01

    Recently, low-level laser (light) therapy (LLLT) has been used to improve muscle performance. This study aimed to evaluate the effectiveness of near-infrared light-emitting diode therapy (LEDT) and its mechanisms of action to improve muscle performance in an elite athlete. The kinetics of oxygen uptake (VO2), blood and urine markers of muscle damage (creatine kinase--CK and alanine), and fatigue (lactate) were analyzed. Additionally, some metabolic parameters were assessed in urine using proton nuclear magnetic resonance spectroscopy ((1)H NMR). A LED cluster with 50 LEDs (λ = 850 nm; 50 mW 15 s; 37.5 J) was applied on legs, arms and trunk muscles of a single runner athlete 5 min before a high-intense constant workload running exercise on treadmill. The athlete received either Placebo-1-LEDT; Placebo-2-LEDT; or Effective-LEDT in a randomized double-blind placebo-controlled trial with washout period of 7 d between each test. LEDT improved the speed of the muscular VO2 adaptation (∼-9 s), decreased O2 deficit (∼-10 L), increased the VO2 from the slow component phase (∼+348 ml min(-1)), and increased the time limit of exercise (∼+589 s). LEDT decreased blood and urine markers of muscle damage and fatigue (CK, alanine and lactate levels). The results suggest that a muscular pre-conditioning regimen using LEDT before intense exercises could modulate metabolic and renal function to achieve better performance.

  13. Color snakes for dynamic lighting conditions on mobile manipulation platforms.

    SciTech Connect

    Schaub, Hanspeter; Smith, Christopher Elmer (University of New Mexico, Albuquerque, NM)

    2003-03-01

    Statistical active contour models (aka statistical pressure snakes) have attractive properties for use in mobile manipulation platforms as both a method for use in visual servoing and as a natural component of a human-computer interface. Unfortunately, the constantly changing illumination expected in outdoor environments presents problems for statistical pressure snakes and for their image gradient-based predecessors. This paper introduces a new color-based variant of statistical pressure snakes that gives superior performance under dynamic lighting conditions and improves upon the previously published results of attempts to incorporate color imagery into active deformable models.

  14. High Intensity Organic Light-emitting Diodes

    NASA Astrophysics Data System (ADS)

    Qi, Xiangfei

    This thesis is dedicated to the fabrication, modeling, and characterization to achieve high efficiency organic light-emitting diodes (OLEDs) for illumination applications. Compared to conventional lighting sources, OLEDs enabled the direct conversion of electrical energy into light emission and have intrigued the world's lighting designers with the long-lasting, highly efficient illumination. We begin with a brief overview of organic technology, from basic organic semiconductor physics, to its application in optoelectronics, i.e. light-emitting diodes, photovoltaics, photodetectors and thin-film transistors. Due to the importance of phosphorescent materials, we will focus on the photophysics of metal complexes that is central to high efficiency OLED technology, followed by a transient study to examine the radiative decay dynamics in a series of phosphorescent platinum binuclear complexes. The major theme of this thesis is the design and optimization of a novel architecture where individual red, green and blue phosphorescent OLEDs are vertically stacked and electrically interconnected by the compound charge generation layers. We modeled carrier generation from the metal-oxide/doped organic interface based on a thermally assisted tunneling mechanism. The model provides insights to the optimization of a stacked OLED from both electrical and optical point of view. To realize the high intensity white lighting source, the efficient removal of heat is of a particular concern, especially in large-area devices. A fundamental transfer matrix analysis is introduced to predict the thermal properties in the devices. The analysis employs Laplace transforms to determine the response of the system to the combined effects of conduction, convection, and radiation. This perspective of constructing transmission matrices greatly facilitates the calculation of transient coupled heat transfer in a general multi-layer composite. It converts differential equations to algebraic forms, and

  15. Isoprenoid emission response to changing light conditions of English oak, European beech and Norway spruce

    NASA Astrophysics Data System (ADS)

    van Meeningen, Ylva; Schurgers, Guy; Rinnan, Riikka; Holst, Thomas

    2017-09-01

    Light is an important environmental factor controlling biogenic volatile organic compound (BVOC) emissions, but in natural conditions its impact is hard to separate from other influential factors such as temperature. We studied the light response of foliar BVOC emissions, photosynthesis and stomatal conductance on three common European tree species, namely English oak (Quercus robur), European beech (Fagus sylvatica) and two provenances of Norway spruce (Picea abies) in Taastrup, Denmark. Leaf scale measurements were performed on the lowest positioned branches of the tree in July 2015. Light intensity was increased in four steps (0, 500, 1000 and 1500 µmol m-2 s-1), whilst other chamber conditions such as temperature, humidity and CO2 levels were fixed. Whereas the emission rate differed between individuals of the same species, the relative contributions of compounds to the total isoprenoid emission remained similar. Whilst some compounds were species specific, the compounds α-pinene, camphene, 3-carene, limonene and eucalyptol were emitted by all of the measured tree species. Some compounds, like isoprene and sabinene, showed an increasing emission response with increasing light intensity, whereas other compounds, like camphene, had no significant emission response to light for most of the measured trees. English oak and European beech showed high light-dependent emission fractions from isoprene and sabinene, but other emitted compounds were light independent. For the two provenances of Norway spruce, the compounds α-pinene, 3-carene and eucalyptol showed high light-dependent fractions for many of the measured trees. This study highlights differences between compound emissions in their response to a change in light and a possible light independence for certain compounds, which might be valid for a wider range of tree species. This information could be of importance when improving emission models and to further emphasize the discussion regarding light or

  16. High Energy Efficiency Air Conditioning

    SciTech Connect

    Edward McCullough; Patrick Dhooge; Jonathan Nimitz

    2003-12-31

    This project determined the performance of a new high efficiency refrigerant, Ikon B, in a residential air conditioner designed to use R-22. The refrigerant R-22, used in residential and small commercial air conditioners, is being phased out of production in developed countries beginning this year because of concerns regarding its ozone depletion potential. Although a replacement refrigerant, R-410A, is available, it operates at much higher pressure than R-22 and requires new equipment. R-22 air conditioners will continue to be in use for many years to come. Air conditioning is a large part of expensive summer peak power use in many parts of the U.S. Previous testing and computer simulations of Ikon B indicated that it would have 20 - 25% higher coefficient of performance (COP, the amount of cooling obtained per energy used) than R-22 in an air-cooled air conditioner. In this project, a typical new R-22 residential air conditioner was obtained, installed in a large environmental chamber, instrumented, and run both with its original charge of R-22 and then with Ikon B. In the environmental chamber, controlled temperature and humidity could be maintained to obtain repeatable and comparable energy use results. Tests with Ikon B included runs with and without a power controller, and an extended run for several months with subsequent analyses to check compatibility of Ikon B with the air conditioner materials and lubricant. Baseline energy use of the air conditioner with its original R-22 charge was measured at 90 deg F and 100 deg F. After changeover to Ikon B and a larger expansion orifice, energy use was measured at 90 deg F and 100 deg F. Ikon B proved to have about 19% higher COP at 90 deg F and about 26% higher COP at 100 deg F versus R-22. Ikon B had about 20% lower cooling capacity at 90 deg F and about 17% lower cooling capacity at 100 deg F versus R-22 in this system. All results over multiple runs were within 1% relative standard deviation (RSD). All of these

  17. Rapidly pulsed, high intensity, incoherent light source

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Brandhorst, H. W., Jr. (Inventor)

    1974-01-01

    A rapid pulsing, high intensity, incoherent light is produced by selectively energizing a plurality of discharge lamps with a triggering circuit. Each lamp is connected to a capacitor, and a power supply is electrically connected to all but one of the capacitors. This last named capacitor is electrically connected to a discharge lamp which is connected to the triggering circuit.

  18. Melatonin administration modifies circadian motor activity under constant light depending on the lighting conditions during suckling.

    PubMed

    Carpentieri, Agata R; Oliva, Clara; Díez-Noguera, Antoni; Cambras, Trinitat

    2015-01-01

    Early lighting conditions have been described to produce long-term effects on circadian behavior, which may also influence the response to agents acting on the circadian system. It has been suggested that melatonin (MEL) may act on the circadian pacemaker and as a scavenger of reactive oxygen and nitrogen species. Here, we studied the oxidative and behavioral changes caused by prolonged exposure to constant light (LL) in groups of rats that differed in MEL administration and in lighting conditions during suckling. The rats were exposed to either a light-dark cycle (LD) or LL. At 40 days old, rats were treated for 2 weeks with a daily subcutaneous injection of MEL (10 mg/kg body weight) or a vehicle at activity onset. Blood samples were taken before and after treatment, to determine catalase (CAT) activity and nitrite level in plasma. As expected, LL-reared rats showed a more stable motor activity circadian rhythm than LD rats. MEL treatment produced more reactivity in LD- than in LL rats, and was also able to alter the phase of the rhythm in LD rats. There were no significant differences in nitrite levels or CAT activity between the groups, although both variables increased with time. Finally, we also tested depressive signs by means of sucrose consumption, and anhedonia was found in LD males treated with MEL. The results suggest that the lighting conditions in early infancy are important for the long-term functionality of the circadian system, including rhythm manifestation, responses to MEL and mood alterations.

  19. HPLC analysis of ballpoint pen inks stored at different light conditions.

    PubMed

    Andrasko, J

    2001-01-01

    A method for comparison of ink entries on documents stored in different light conditions is presented. Various blue inks were exposed to light, both daylight and artificial light from fluorescent tubes. Inks were then extracted from the document and analyzed by HPLC (high performance liquid chromatography). Significant changes in composition were noted on exposure to light. These changes were followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. Also, the amount of the various compounds formed by decomposition of these dyes on exposure to light was measured and employed for comparison of inks. An example of the use of the proposed method in casework is given.

  20. Control of Laser High-Harmonic Generation with Counterpropagating Light

    NASA Astrophysics Data System (ADS)

    Voronov, S. L.; Kohl, I.; Madsen, J. B.; Simmons, J.; Terry, N.; Titensor, J.; Wang, Q.; Peatross, J.

    2001-09-01

    Relatively weak counterpropagating light is shown to disrupt the emission of laser high-harmonic generation. Harmonic orders ranging from the teens to the low thirties produced by a 30-femtosecond pulse in a narrow argon jet are ``shut down'' with a contrast as high as 2 orders of magnitude by a chirped 1-picosecond counterpropagating laser pulse (60 times less intense). Alternatively, under poor phase-matching conditions, the counterpropagating light boosts harmonic production by similar contrast through quasiphase matching where out-of-phase emission is suppressed.

  1. Circadian Oscillation of the Lettuce Transcriptome under Constant Light and Light-Dark Conditions.

    PubMed

    Higashi, Takanobu; Aoki, Koh; Nagano, Atsushi J; Honjo, Mie N; Fukuda, Hirokazu

    2016-01-01

    Although, the circadian clock is a universal biological system in plants and it orchestrates important role of plant production such as photosynthesis, floral induction and growth, there are few such studies on cultivated species. Lettuce is one major cultivated species for both open culture and plant factories and there is little information concerning its circadian clock system. In addition, most of the relevant genes have not been identified. In this study, we detected circadian oscillation in the lettuce transcriptome using time-course RNA sequencing (RNA-Seq) data. Constant light (LL) and light-dark (LD) conditions were used to detect circadian oscillation because the circadian clock has some basic properties: one is self-sustaining oscillation under constant light and another is entrainment to environmental cycles such as light and temperature. In the results, 215 contigs were detected as common oscillating contigs under both LL and LD conditions. The 215 common oscillating contigs included clock gene-like contigs CCA1 (CIRCADIAN CLOCK ASSOCIATED 1)-like, TOC1 (TIMING OF CAB EXPRESSION 1)-like and LHY (LATE ELONGATED HYPOCOTYL)-like, and their expression patterns were similar to those of Arabidopsis. Functional enrichment analysis by GO (gene ontology) Slim and GO Fat showed that the GO terms of response to light stimulus, response to stress, photosynthesis and circadian rhythms were enriched in the 215 common oscillating contigs and these terms were actually regulated by circadian clocks in plants. The 215 common oscillating contigs can be used to evaluate whether the gene expression pattern related to photosynthesis and optical response performs normally in lettuce.

  2. Employees' perception of lighting conditions in manufacturing plants: associations with illuminance measurements.

    PubMed

    Vahedi, Abdollah; Dianat, Iman

    2014-01-01

    The aims of this study were to evaluate the employees' subjective assessments of different aspects of lighting condition as well as task area illuminance in manufacturing plants. This field study was conducted between March and May 2013, in three packing plants (Saveh, central Iran). Data were collected by questionnaire and measurement of the task area illuminance levels. Data were analysed using contingency coefficient test, Spearman's correlation analysis and non-parametric Friedman tests. The recommended illuminance levels were not met in 46.9% of the work areas. This finding was in agreement with the employees' perception of light level, and with low satisfaction with lighting in the work environment. Adverse effects of lighting condition on job performance, changing posture for better viewing of the work area and eye tiredness were reported as 64%, 33% and 31% of the employees, respectively. Satisfaction with lighting was negatively correlated with the age of respondents (r=-0.229; P<0.010). The employees' satisfaction with lighting was also highly correlated with the employees' subjective assessments of the light level (r=0.779; P<0.001), type of artificial light sources (r=0.591; P<0.001), light colour (r=0.50; P<0.001) and use of daylight (r=0.254; P<0.004). The type of artificial light sources was correlated with job performance (r=0.311, P<0.001) and eye tiredness (r=0.273; P<0.002). The findings highlight the potential usefulness of subjective assessments to supplement objective measures and provide a more holistic approach to lighting design and planning.

  3. Blue light is essential for high light acclimation and photoprotection in the diatom Phaeodactylum tricornutum

    PubMed Central

    Wilhelm, Christian

    2013-01-01

    The objective of the present study was to test the hypothesis that the acclimation to different light intensities in the diatom Phaeodactylum tricornutum is controlled by light quality perception mechanisms. Therefore, semi-continuous cultures of P. tricornutum were illuminated with equal amounts of photosynthetically absorbed radiation of blue (BL), white (WL), and red light (RL) and in combination of two intensities of irradiance, low (LL) and medium light (ML). Under LL conditions, growth rates and photosynthesis rates were similar for all cultures. However, BL cultures were found to be in an acclimation state with an increased photoprotective potential. This was deduced from an increased capacity of non-photochemical quenching, a larger pool of xanthophyll cycle pigments, and a higher de-epoxidation state of xanthophyll cycle pigments compared to WL and RL cultures. Furthermore, in the chloroplast membrane proteome of BL cells, an upregulation of proteins involved in photoprotection, e.g. the Lhcx1 protein and zeaxanthin epoxidase, was evident. ML conditions induced increased photosynthesis rates and a further enhanced photoprotective potential for algae grown under BL and WL. In contrast, RL cultures exhibited no signs of acclimation towards increased irradiance. The data implicate that in diatoms the photoacclimation to high light intensities requires the perception of blue light. PMID:23183259

  4. High-definition imaging system based on spatial light modulators with light-scattering mode.

    PubMed

    Kikuchi, Hiroshi; Fujii, Takanori; Kawakita, Masahiro; Hirano, Yoshiyuki; Fujikake, Hideo; Sato, Fumio; Takizawa, Kuniharu

    2004-01-01

    We have developed a prototype high-definition imaging system using polymer-dispersed liquid-crystal (PDLC) light valves, which can modulate unpolarized light with high spatial resolution and exhibit a high optical efficiency, based on the light-scattering effect. We fabricated high-definition light valves with a fine polymer-matrix structure in a PDLC film by controlling the curing conditions used during the photopolymerization-induced phase separation and formation process. This device has excellent characteristics, such as a high resolution, with 50 lp/mm for a limiting resolution and greater than 20 lp/mm at the 50% modulation transfer function point, and a reflectivity of greater than 60%. An optically addressable full-color projection display was designed, consisting of three PDLC light valves, a schlieren optical system based on shift-decentralization optics with a xenon lamp illumination and input-image sources with 1.5 million pixels, including electrical image compensation of the gamma characteristics. We succeeded in displaying pictures on a 110-inch screen with a resolution of 810 TV lines and a luminous flux of 1900-2100 American National Standards Institute lumens.

  5. Neuroleptics under high risk conditions.

    PubMed

    Oyewumi, L K

    1983-08-01

    A critical review of various high risk situations in which neuroleptics could be used and have been used in clinical practice is presented. These high risk situations include: women of child bearing age (pregnant women, lactating and/or nursing mothers), the two extremes of life (children and the elderly), patients with sexual dysfunction, patients with tardive dyskinesia, non-psychotic psychiatric patients, physically ill and suicidal patients. The extraordinary applications of these drugs, such as for rapid tranquilization and megadose regimens are examined. The author provides guidelines for the use of neuroleptics in these clinical situations.

  6. Morph specific foraging behavior by a polymorphic raptor under variable light conditions.

    PubMed

    Tate, Gareth J; Amar, Arjun

    2017-08-22

    Colour polymorphism may be maintained within a population by disruptive-selection. One hypothesis proposes that different morphs are adapted to different ambient light conditions, with lighter morphs having a selective advantage in bright conditions and darker morphs having advantages in darker conditions. The mechanism for this advantage is proposed to be through enhanced crypsis via background-matching. We explore this hypothesis in a polymorphic raptor, the black sparrowhawk Accipiter melanoleucus, which exhibits a discrete dark and white-morph. We use GPS-tracking data to contrast the foraging behaviour and habitat selection of morphs. As predicted, we found that light-levels influenced foraging behaviour in different ways for morphs: Dark-morphs showed a decrease in foraging with increasing light-levels; whereas no relationship was found for white-morphs. Furthermore, we found differential-degrees of habitat selection, with dark-morphs selecting more enclosed habitats compared to white-morphs. This suggests that different morphs may be better adapted to foraging under different light-conditions, potentially playing a role in maintaining colour polymorphism in this species. Our results may also help explain why dark-morphs predominate in this study region, which experiences high rainfall and lower light-levels during the breeding-period. This study suggests that avian morphs may allocate/partition foraging activity by weather conditions/habitat, which maximise their concealment from prey.

  7. Thermostability of plants in various light conditions of cultivation

    NASA Astrophysics Data System (ADS)

    Zavorueva, Elena

    2004-12-01

    At various levels of PHAR with the help of measurement of parameters of a slow induction of chlorophyll fluorescence at 682 and 734 nm in light culture conditions the thermostable estimation of cenosises of plants of wheat and radish in reply to action of the raise and damaging temperatures of air (35°C 20 hours, 45°C 7 hours) is carried out. Without dependence from a level of light exposure, the exposition of cenosises at 35°C did not result in irreversible changes of the photosynthetic device of plants. The minimal damage of cenosises of wheat and radish at influence of temperature of 45°C is observed at 150W/m2 of PHAR, and maximal - at intensities, close to a level of a compensatory point of photosynthesis of cenosises (50-70 W/m2 PHAR at a temperature of air of 24°C). The index of viability is most sensitive parameter in comparison with other parameters determined by a method of a slow induction of fluorescence at 682 and 734 nm. The character of its change in reply to action of the stress-factor coincides with changes of intensity of photosynthesis researched of cenosises.

  8. [Effects of light condition on structure and photosynthetic characteristics of leaves in 'Hanfu' apple].

    PubMed

    Ma, Hui-Li; Lu, De-Guo

    2014-07-01

    By using microscope technique and gas exchange method, the effects of light conditions on structure and photosynthetic characteristics of the leaves were studied with potted and fielded 'Hanfu' apple as materials. The results showed that the palisade tissue, spongy tissue and the total leaf thickness of 'Hanfu' apple was declined under the weak light environment, the palisade tissue were declined by 34.5% (pot) and 25.0% (field), and the total leaf thickness were declined by 27.1% (pot) and 18.3% (field). The light compensation point (LCP) of the field shading leaves was lowest (30.8 +/- 1.3 micromol x m(-2) x s(-1)), the saturation point (LSP) in full light was 22.7% (pot) and 48.2% (field) higher than in shading, respectively. The adaptability of the potted 'Hanfu' apple leaves built under different light conditions had different resistivity after exposing to high light, the startup time of maximum photosynthetic rates (15.4 micromol x m(-2) x s(-1) in full light and 12.7 micromol x m(-2) x s(-1) in shading) were different, which was 23 min and 33 min, respectively. Long-time shading impacted on the quality and photosynthetic capacity of 'Hanfu' apple leaves.

  9. High-intensity sources for light ions

    SciTech Connect

    Leung, K.N.

    1995-10-01

    The use of the multicusp plasma generator as a source of light ions is described. By employing radio-frequency induction discharge, the performance of the multicusp source is greatly improved, both in lifetime and in high brightness H{sup +} and H{sup {minus}} beam production. A new technique for generating multiply-charged ions in this type of ion source is also presented.

  10. High gradient accelerators for linear light sources

    SciTech Connect

    Barletta, W.A.

    1988-09-26

    Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.

  11. Conditioned and battery standby power for traffic light systems

    SciTech Connect

    Higgins, A.N. )

    1989-10-01

    Electronic devices and control systems are found in every facet of our high-tech society. They derive their operating power from conventional utility service or battery power. Included among such high-tech electronics are traffic signal lights and their control systems, which use microprocessors and other sophisticated electronics for their operation. Unfortunately, like most other electrically operated equipment traffic equipment is also at the mercy of the utility company, weather, construction operations, automobile accidents, and a variety of other sources of noise and interruptions to the power source. In addition to the quality of the power (i.e., its regulation and freedom from noise and transients), there are often times when complete outages occur. This article proposes using a ferroresonant transformer combined with a battery standby power system to solve the problems of poor quality utility power and power outages. This system would reduce manpower requirements during short power outages, protect traffic equipment from transients and noise, and minimize possible safety hazards caused by inoperative traffic light systems.

  12. High Quantum Efficiency OLED Lighting Systems

    SciTech Connect

    Shiang, Joseph

    2011-09-30

    The overall goal of the program was to apply improvements in light outcoupling technology to a practical large area plastic luminaire, and thus enable the product vision of an extremely thin form factor high efficiency large area light source. The target substrate was plastic and the baseline device was operating at 35 LPW at the start of the program. The target LPW of the program was a >2x improvement in the LPW efficacy and the overall amount of light to be delivered was relatively high 900 lumens. Despite the extremely difficult challenges associated with scaling up a wet solution process on plastic substrates, the program was able to make substantial progress. A small molecule wet solution process was successfully implemented on plastic substrates with almost no loss in efficiency in transitioning from the laboratory scale glass to large area plastic substrates. By transitioning to a small molecule based process, the LPW entitlement increased from 35 LPW to 60 LPW. A further 10% improvement in outcoupling efficiency was demonstrated via the use of a highly reflecting cathode, which reduced absorptive loss in the OLED device. The calculated potential improvement in some cases is even larger, ~30%, and thus there is considerable room for optimism in improving the net light coupling efficacy, provided absorptive loss mechanisms are eliminated. Further improvements are possible if scattering schemes such as the silver nanowire based hard coat structure are fully developed. The wet coating processes were successfully scaled to large area plastic substrate and resulted in the construction of a 900 lumens luminaire device.

  13. Physiological and pathological clinical conditions and light scattering in brain

    NASA Astrophysics Data System (ADS)

    Kurata, Tsuyoshi; Iwata, Sachiko; Tsuda, Kennosuke; Kinoshita, Masahiro; Saikusa, Mamoru; Hara, Naoko; Oda, Motoki; Ohmae, Etsuko; Araki, Yuko; Sugioka, Takashi; Takashima, Sachio; Iwata, Osuke

    2016-08-01

    MRI of preterm infants at term commonly reveals subtle brain lesions such as diffuse white matter injury, which are linked with later cognitive impairments. The timing and mechanism of such injury remains unclear. The reduced scattering coefficient of near-infrared light (μs’) has been shown to correlate linearly with gestational age in neonates. To identify clinical variables associated with brain μs’, 60 preterm and full-term infants were studied within 7 days of birth. Dependence of μs’ obtained from the frontal head on clinical variables was assessed. In the univariate analysis, smaller μs’ was associated with antenatal glucocorticoid, emergency Caesarean section, requirement for mechanical ventilation, smaller gestational age, smaller body sizes, low 1- and 5-minute Apgar scores, higher cord blood pH and PO2, and higher blood HCO3- at the time of study. Multivariate analysis revealed that smaller gestational age, requirement for mechanical ventilation, and higher HCO3- at the time of study were correlated with smaller μs’. Brain μs’ depended on variables associated with physiological maturation and pathological conditions of the brain. Further longitudinal studies may help identify pathological events and clinical conditions responsible for subtle brain injury and subsequent cognitive impairments following preterm birth.

  14. Aural-Nondetectability Model Predictions for Night-Vision Goggles across Ambient Lighting Conditions

    DTIC Science & Technology

    2015-12-01

    The present work by the US Army Research Laboratory (ARL) measures the acoustic output of 6 NVGs under 3 different lighting conditions that...Ambient Lighting Conditions by Jeremy Gaston, Ashley Foots, Christopher Stachowiak, and Samantha Chambers Approved for...Lighting Conditions Jeremy Gaston, Ashley Foots, Christopher Stachowiak, and Samantha Chambers Human Research and Engineering Directorate, ARL

  15. Physiological and antioxidant responses of two accessions of Arabidopsis thaliana in different light and temperature conditions.

    PubMed

    Szymańska, Renata; Nowicka, Beatrycze; Gabruk, Michał; Glińska, Sława; Michlewska, Sylwia; Dłużewska, Jolanta; Sawicka, Anna; Kruk, Jerzy; Laitinen, Roosa

    2015-06-01

    During their lifetime, plants need to adapt to a changing environment, including light and temperature. To understand how these factors influence plant growth, we investigated the physiological and antioxidant responses of two Arabidopsis accessions, Shahdara (Sha) from the Shahdara valley (Tajikistan, Central Asia) in a mountainous area and Lovvik-5 (Lov-5) from northern Sweden to different light and temperature conditions. These accessions originate from different latitudes and have different life strategies, both of which are known to be influenced by light and temperature. We showed that both accessions grew better in high-light and at a lower temperature (16°C) than in low light and at 23°C. Interestingly, Sha had a lower chlorophyll content but more efficient non-photochemical quenching than Lov-5. Sha, also showed a higher expression of vitamin E biosynthetic genes. We did not observe any difference in the antioxidant prenyllipid level under these conditions. Our results suggest that the mechanisms that keep the plastoquinone (PQ)-pool in more oxidized state could play a role in the adaptation of these accessions to their local climatic conditions.

  16. Improving the range of UHF RFID transponders using solar energy harvesting under low light conditions

    NASA Astrophysics Data System (ADS)

    Ascher, A.; Lehner, M.; Eberhardt, M.; Biebl, E.

    2015-11-01

    The sensitivity of passive UHF RFID transponders (Radio Frequency Identification) is the key issue, which determines the maximum read range of an UHF RFID system. During this work the ability of improving the sensitivity using solar energy harvesting, especially for low light conditions, is shown. To use the additional energy harvested from the examined silicon and organic solar cells, the passive RFID system is changed into a semi-active one. This needs no changes on the reader hardware itself, only the used RFIC (Radio Frequency Integrated Circuit) of the transponder has to possess an additional input pin for an external supply voltage. The silicon and organic cells are evaluated and compared to each other regarding their low light performance. The different cells are examined in a shielded box, which is protected from the environmental lighting. Additionally, a demonstrator is shown, which makes the measurement of the extended read range with respect to the lighting conditions possible. If the cells are completely darkened, the sensitivity gain is ascertained using high capacity super caps. Due to the measurements an enhancement in range up to 70 % could be guaranteed even under low light conditions.

  17. Influence of Light Conditions and Light Sources on Clinical Measurement of Natural Teeth Color using VITA Easyshade Advance 4,0® Spectrophotometer. Pilot Study.

    PubMed Central

    Posavec, Ivona; Prpić, Vladimir

    2016-01-01

    Objectives The purpose of this study was to evaluate and compare lightness (L), chroma (C) and hue (h), green-red (a) and blue-yellow (b) character of the color of maxillary right central incisors in different light conditions and light sources. Materials and methods Two examiners who were well trained in digital color evaluation participated in the research. Intraclass correlation coefficients (ICCs) were used to analyze intra- and interobserver reliability. The LCh and L*a*b* values were determined at 08.15 and at 10.00 in the morning under three different light conditions. Tooth color was assessed in 10 subjects using intraoral spectrophotometer VITA Easyshade Advance 4.0® set at the central region of the vestibular surface of the measured tooth. Results Intra- and interobserver ICC values were high for both examiners and ranged from 0.57 to 0.99. Statistically significant differences in LCh and L*a*b* values measured in different time of the day and certain light condition were not found (p>0.05). Statistically significant differences in LCh and L*a*b* values measured under three different light conditions were not found, too (p>0.05). Conclusions VITA Easyshade Advance 4.0® is reliable enough for daily clinical work in order to assess tooth color during the fabrication of esthtic appliances because it is not dependent on light conditions and light sources. PMID:28275281

  18. Influence of Light Conditions and Light Sources on Clinical Measurement of Natural Teeth Color using VITA Easyshade Advance 4,0(®) Spectrophotometer. Pilot Study.

    PubMed

    Posavec, Ivona; Prpić, Vladimir; Zlatarić, Dubravka Knezović

    2016-12-01

    The purpose of this study was to evaluate and compare lightness (L), chroma (C) and hue (h), green-red (a) and blue-yellow (b) character of the color of maxillary right central incisors in different light conditions and light sources. Two examiners who were well trained in digital color evaluation participated in the research. Intraclass correlation coefficients (ICCs) were used to analyze intra- and interobserver reliability. The LCh and L*a*b* values were determined at 08.15 and at 10.00 in the morning under three different light conditions. Tooth color was assessed in 10 subjects using intraoral spectrophotometer VITA Easyshade Advance 4.0(®) set at the central region of the vestibular surface of the measured tooth. Intra- and interobserver ICC values were high for both examiners and ranged from 0.57 to 0.99. Statistically significant differences in LCh and L*a*b* values measured in different time of the day and certain light condition were not found (p>0.05). Statistically significant differences in LCh and L*a*b* values measured under three different light conditions were not found, too (p>0.05). VITA Easyshade Advance 4.0(®) is reliable enough for daily clinical work in order to assess tooth color during the fabrication of esthtic appliances because it is not dependent on light conditions and light sources.

  19. Pre-conditioning with low-level laser (light) therapy: light before the storm.

    PubMed

    Agrawal, Tanupriya; Gupta, Gaurav K; Rai, Vikrant; Carroll, James D; Hamblin, Michael R

    2014-12-01

    Pre-conditioning by ischemia, hyperthermia, hypothermia, hyperbaric oxygen (and numerous other modalities) is a rapidly growing area of investigation that is used in pathological conditions where tissue damage may be expected. The damage caused by surgery, heart attack, or stroke can be mitigated by pre-treating the local or distant tissue with low levels of a stress-inducing stimulus, that can induce a protective response against subsequent major damage. Low-level laser (light) therapy (LLLT) has been used for nearly 50 years to enhance tissue healing and to relieve pain, inflammation and swelling. The photons are absorbed in cytochrome(c) oxidase (unit four in the mitochondrial respiratory chain), and this enzyme activation increases electron transport, respiration, oxygen consumption and ATP production. A complex signaling cascade is initiated leading to activation of transcription factors and up- and down-regulation of numerous genes. Recently it has become apparent that LLLT can also be effective if delivered to normal cells or tissue before the actual insult or trauma, in a pre-conditioning mode. Muscles are protected, nerves feel less pain, and LLLT can protect against a subsequent heart attack. These examples point the way to wider use of LLLT as a pre-conditioning modality to prevent pain and increase healing after surgical/medical procedures and possibly to increase athletic performance.

  20. Pre-Conditioning with Low-Level Laser (Light) Therapy: Light Before the Storm

    PubMed Central

    Agrawal, Tanupriya; Gupta, Gaurav K.; Rai, Vikrant; Carroll, James D.; Hamblin, Michael R.

    2014-01-01

    Pre-conditioning by ischemia, hyperthermia, hypothermia, hyperbaric oxygen (and numerous other modalities) is a rapidly growing area of investigation that is used in pathological conditions where tissue damage may be expected. The damage caused by surgery, heart attack, or stroke can be mitigated by pre-treating the local or distant tissue with low levels of a stress-inducing stimulus, that can induce a protective response against subsequent major damage. Low-level laser (light) therapy (LLLT) has been used for nearly 50 years to enhance tissue healing and to relieve pain, inflammation and swelling. The photons are absorbed in cytochrome(c) oxidase (unit four in the mitochondrial respiratory chain), and this enzyme activation increases electron transport, respiration, oxygen consumption and ATP production. A complex signaling cascade is initiated leading to activation of transcription factors and up- and down-regulation of numerous genes. Recently it has become apparent that LLLT can also be effective if delivered to normal cells or tissue before the actual insult or trauma, in a pre-conditioning mode. Muscles are protected, nerves feel less pain, and LLLT can protect against a subsequent heart attack. These examples point the way to wider use of LLLT as a pre-conditioning modality to prevent pain and increase healing after surgical/medical procedures and possibly to increase athletic performance. PMID:25552961

  1. The JLab high power ERL light source

    SciTech Connect

    G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

    2005-03-19

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made

  2. The JLab high power ERL light source

    NASA Astrophysics Data System (ADS)

    Neil, G. R.; Behre, C.; Benson, S. V.; Bevins, M.; Biallas, G.; Boyce, J.; Coleman, J.; Dillon-Townes, L. A.; Douglas, D.; Dylla, H. F.; Evans, R.; Grippo, A.; Gruber, D.; Gubeli, J.; Hardy, D.; Hernandez-Garcia, C.; Jordan, K.; Kelley, M. J.; Merminga, L.; Mammosser, J.; Moore, W.; Nishimori, N.; Pozdeyev, E.; Preble, J.; Rimmer, R.; Shinn, M.; Siggins, T.; Tennant, C.; Walker, R.; Williams, G. P.; Zhang, S.

    2006-02-01

    A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz ˜ half cycle pulse whose average brightness is >5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted [Carr, et al., Nature 420 (2002) 153]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [Neil, et al., Phys. Rev. Lett. 84 (2000) 662]: up to 10 kW of average power in the IR from 1 to 14 μm in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 ms long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the

  3. Chloroplast Distribution in Arabidopsis thaliana (L.) Depends on Light Conditions during Growth.

    PubMed Central

    Trojan, A.; Gabrys, H.

    1996-01-01

    Chloroplasts of Arabidopsis thaliana move in response to blue light. Sensitivity to light and the range of fluence rates to which the chloroplasts respond were found to be comparable to those of other higher plants studied. We investigated typical chloroplast distributions in Arabidopsis grown under three different light conditions:standard-light conditions, similar to natural light intensities; weak-light intensities, close to the compensation point of photosynthesis; and strong-light intensities, close to the saturation of the light-response curve of photosynthesis. We observed a striking difference in chloroplast arrangement in darkness between plants grown under weak- and strong-light conditions. There was a slight difference after weak-light pretreatment, and the arrangements of chloroplasts after strong-light pretreatment in both plant groups were very similar. These results support the ecological significance of chloroplast movements. PMID:12226297

  4. Light shield and cooling apparatus. [high intensity ultraviolet lamp

    NASA Technical Reports Server (NTRS)

    Meador, T. G., Jr. (Inventor)

    1974-01-01

    A light shield and cooling apparatus was developed for a high intensity ultraviolet lamp including water and high pressure air for cooling and additional apparatus for shielding the light and suppressing the high pressure air noise.

  5. High-fat feeding alters the clock synchronization to light.

    PubMed

    Mendoza, Jorge; Pévet, Paul; Challet, Etienne

    2008-12-15

    High-fat feeding in rodents leads to metabolic abnormalities mimicking the human metabolic syndrome, including obesity and insulin resistance. These metabolic diseases are associated with altered temporal organization of many physiological functions. The master circadian clock located in the suprachiasmatic nuclei controls most physiological functions and metabolic processes. Furthermore, under certain conditions of feeding (hypocaloric diet), metabolic cues are capable of altering the suprachiasmatic clock's responses to light. To determine whether high-fat feeding (hypercaloric diet) can also affect resetting properties of the suprachiasmatic clock, we investigated photic synchronization in mice fed a high-fat or chow (low-fat) diet for 3 months, using wheel-running activity and body temperature rhythms as daily phase markers (i.e. suprachiasmatic clock's hands). Compared with the control diet, mice fed with the high-fat diet exhibited increased body mass index, hyperleptinaemia, higher blood glucose, and increased insulinaemia. Concomitantly, high-fat feeding led to impaired adjustment to local time by photic resetting. At the behavioural and physiological levels, these alterations include slower rate of re-entrainment of behavioural and body temperature rhythms after 'jet-lag' test (6 h advanced light-dark cycle) and reduced phase-advancing responses to light. At a molecular level, light-induced phase shifts have been correlated, within suprachiasmatic cells, with a high induction of c-FOS, the protein product of immediate early gene c-fos, and phosphorylation of the extracellular signal-regulated kinases I/II (P-ERK). In mice fed a high-fat diet, photic induction of both c-FOS and P-ERK in the suprachiasmatic nuclei was markedly reduced. Taken together, the present data demonstrate that high-fat feeding modifies circadian synchronization to light.

  6. Very high numerical aperture light transmitting device

    DOEpatents

    Allison, Stephen W.; Boatner, Lynn A.; Sales, Brian C.

    1998-01-01

    A new light-transmitting device using a SCIN glass core and a novel calcium sodium cladding has been developed. The very high index of refraction, radiation hardness, similar solubility for rare earths and similar melt and viscosity characteristics of core and cladding materials makes them attractive for several applications such as high-numerical-aperture optical fibers and specialty lenses. Optical fibers up to 60 m in length have been drawn, and several simple lenses have been designed, ground, and polished. Preliminary results on the ability to directly cast optical components of lead-indium phosphate glass are also discussed as well as the suitability of these glasses as a host medium for rare-earth ion lasers and amplifiers.

  7. Light weight high-stiffness stage platen

    DOEpatents

    Spence, Paul A.

    2001-01-01

    An improved light weight, stiff stage platen for photolithography is provided. The high stiffness of the stage platen is exemplified by a relatively high first resonant vibrational mode as determined, for instance, by finite element modal analysis. The stage platen can be employed to support a chuck that is designed to secure a mask or wafer. The stage platen includes a frame that has interior walls that define an interior region and that has exterior walls wherein the outer surfaces of at least two adjacent walls are reflective mirror surfaces; and a matrix of ribs within the interior region that is connected to the interior walls wherein the stage platen exhibits a first vibrational mode at a frequency of greater than about 1000 Hz.

  8. High Efficiency, Illumination Quality OLEDs for Lighting

    SciTech Connect

    Joseph Shiang; James Cella; Kelly Chichak; Anil Duggal; Kevin Janora; Chris Heller; Gautam Parthasarathy; Jeffery Youmans; Joseph Shiang

    2008-03-31

    The goal of the program was to demonstrate a 45 lumen per watt white light device based upon the use of multiple emission colors through the use of solution processing. This performance level is a dramatic extension of the team's previous 15 LPW large area illumination device. The fundamental material system was based upon commercial polymer materials. The team was largely able to achieve these goals, and was able to deliver to DOE a 90 lumen illumination source that had an average performance of 34 LPW a 1000 cd/m{sup 2} with peak performances near 40LPW. The average color temperature is 3200K and the calculated CRI 85. The device operated at a brightness of approximately 1000cd/m{sup 2}. The use of multiple emission colors particularly red and blue, provided additional degrees of design flexibility in achieving white light, but also required the use of a multilayered structure to separate the different recombination zones and prevent interconversion of blue emission to red emission. The use of commercial materials had the advantage that improvements by the chemical manufacturers in charge transport efficiency, operating life and material purity could be rapidly incorporated without the expenditure of additional effort. The program was designed to take maximum advantage of the known characteristics of these material and proceeded in seven steps. (1) Identify the most promising materials, (2) assemble them into multi-layer structures to control excitation and transport within the OLED, (3) identify materials development needs that would optimize performance within multilayer structures, (4) build a prototype that demonstrates the potential entitlement of the novel multilayer OLED architecture (5) integrate all of the developments to find the single best materials set to implement the novel multilayer architecture, (6) further optimize the best materials set, (7) make a large area high illumination quality white OLED. A photo of the final deliverable is shown. In

  9. Light conditions affect the performance of Yponomeuta evonymellus on its native host Prunus padus and the alien Prunus serotina.

    PubMed

    Łukowski, A; Giertych, M J; Walczak, U; Baraniak, E; Karolewski, P

    2017-04-01

    The bird cherry ermine moth, Yponomeuta evonymellus L., is considered an obligatory monophagous insect pest that feeds only on native European Prunus padus L. In recent years, however, increased larval feeding on alien P. serotina Ehrh. has been observed. In both species, general defoliation is extensive for shade grown trees, whereas it is high in P. padus, but very low in P. serotina, when trees are grown in full light conditions. The aim of the present study was to identify how the plant host species and light conditions affect the performance of Y. evonymellus. The influence of host species and light condition on their growth and development, characterized by the parameters of pupation, adult eclosion, body mass, potential fecundity, and wing size, was measured in a 2 × 2 experimental design (two light treatments, two hosts). In comparison with high light (HL) conditions, a greater percentage of pupation and a longer period and less dynamic adult emerge was observed under low light (LL) conditions. The effect of host species on these parameters was not significant. In contrast, mass, fecundity and all of the studied wing parameters were higher in larvae that grazed on P. padus than on P. serotina. Similarly the same parameters were also higher on shrubs in HL as compared with those grown under LL conditions. In general, light conditions, rather than plant species, were more often and to a greater extent, responsible for differences in the observed parameters of insect development and potential fecundity.

  10. Energy Effective Courtroom Lighting: An Analysis of Existing Conditions and Recommended Improvements

    SciTech Connect

    Jones, Carol C.; Richman, Eric E.

    2006-03-31

    Providing high quality and energy efficient lighting in courtrooms is a complex task, and it represents a greater challenge than most other Federal space types. Energy efficient lighting in courtrooms must be accomplished with no sacrifice in quality; efficiency must be effectively invisible to the occupants. The Whole Building Design Guide puts forth the goals well: “As the preeminent symbol of Federal authority in local communities, a Federal courthouse must express solemnity, stability, integrity, rigor and fairness.” The courtrooms themselves must have a sense of majesty and be aesthetically inspiring. When paired with the visual needs in a courtroom—given the wide variety of tasks and the critical nature of the courtroom proceedings—one has a challenge indeed. In consideration of these issue, this report reviews existing conditions in courtrooms and provides specific guidance about solutions that will accomplish the dual objectives of high quality and energy efficiency. The material covers all aspects of courtroom lighting, including design criteria, design and application strategies, energy efficient technologies, procurement and team selection, design process and implementation, and education. A detailed energy analysis was performed to develop a baseline for energy consumption in courtroom lighting, and the primary root cause was found to be a high use of incandescent technology. Point-by-point calculations were completed to provide an energy efficient alternative that met the high level of criteria for performance in courtrooms. Additional detailed guidance has been provided in the spirit of a holistic solution. It is hoped and anticipated that the recommended solutions will transform courtroom lighting towards both energy efficiency and high quality lighting. This is more important than ever before given the passage of the Energy Policy Act of 2005, which significantly changes the energy usage requirements in Federal Buildings. Ultimately it is

  11. Adaptation of light-harvesting systems of Arthrospira platensis to light conditions, probed by time-resolved fluorescence spectroscopy.

    PubMed

    Akimoto, Seiji; Yokono, Makio; Hamada, Fumiya; Teshigahara, Ayaka; Aikawa, Shimpei; Kondo, Akihiko

    2012-08-01

    Cyanobacteria change the quantity and/or quality of their pigment-protein complexes in response to light conditions. In the present study, we analyzed excitation relaxation dynamics in the cyanobacterium, Arthrospira (Spirulina) platensis, grown under lights exhibiting different spectral profiles, by means of steady-state absorption and picosecond time-resolved fluorescence spectroscopies. It was found that F760, which is the PSI red-chlorophyll characteristic of A. platensis, contributes to slower energy-transfer phase in the PSI of A. platensis. Excitation energy transfers in phycobilisome and those from PSII to PSI were modified depending on the light quality. Existence of quencher was suggested in PSI of the blue-light grown cells. Phycobilisomes in the green-light grown cells and the far-red-light grown cells transferred excitation energy from phycobilisome to chlorophyll without loss of energy. In these cells, excitation energy was shared between two photosystems. Fast energy transfer was established in phycobilisome under the yellow-light condition where only the phycobilisome can absorb the cultivation light. Differences in light-harvesting and energy-transfer processes under different cultivation-light conditions are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Deterioration of the high-mounted brake light.

    PubMed

    Cameron, D L

    1995-10-01

    An unusually high failure rate in the high-mounted, center brake light was observed in a survey of normal local traffic. Such failure increases the potential for delay or error in perception of the rear lights by following drivers.

  13. Vertical Stand Transparent Light-Emitting Diode Architecture for High-Efficiency and High-Power Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Pan, Chih-Chien; Koslow, Ingrid; Sonoda, Junichi; Ohta, Hiroaki; Ha, Jun-Seok; Nakamura, Shuji; DenBaars, Steven P.

    2010-08-01

    Using a transparent ZnO vertical stand as a submount, a novel Light-emitting diode architecture, which is similar to conventional lighting bulbs, was proposed. The emission power of a blue LED based on c-plane (0001) bulk GaN was increased by 14.2 and 5.1% compared with those of conventional and suspended die packages, respectively. The output power and external quantum efficiency of LEDs respectively reached 31.7 mW and 57.1% at a forward current of 20 mA under direct current conditions. The high thermal conductivity and refractive index of the transparent submount simultaneously resulted in high current operation and high external efficiency.

  14. The Jefferson Lab High Power Light Source

    SciTech Connect

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  15. The Jefferson Lab High Power Light Source

    SciTech Connect

    Boyce, James R.

    2006-01-03

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  16. Highly Automated Module Production Incorporating Advanced Light Management

    SciTech Connect

    Perelli-Minetti, Michael; Roof, Kyle

    2015-08-11

    The objective was to enable a high volume, cost effective solution for increasing the amount of light captured by PV modules through utilization of an advanced Light Re-directing Film and to follow a phased approach to develop and implement this new technology in order to achieve an expected power gain of up to 12 watts per module. Full size PV modules were manufactured using a new Light Redirecting Film (LRF) material applied to two different areas of PV modules in order to increase the amount of light captured by the modules. One configuration involved applying thin strips of LRF film over the tabbing ribbon on the cells in order to redirect the light that is normally absorbed by the tabbing ribbon to the active areas of the cells. A second configuration involved applying thin strips of LRF film over the white spaces between cells within a module in order to capture some of the light that is normally reflected from the white areas back through the front glass of the modules. Significant power increases of 1.4% (3.9 watts) and 1.0% (3.2 watts), respectively, compared to standard PV modules were measured under standard test conditions. The performance of PV modules with LRF applied to the tabbing ribbon was modeled. The results showed that the power increase provided by LRF depended greatly on the angle of incident light with the optimum performance only occurring when the light was within a narrow range of being perpendicular to the solar module. The modeling showed that most of the performance gain would be lost when the angle of incident light was greater than 28 degrees off axis. This effect made the orientation of modules with LRF applied to tabbing ribbons very important as modules mounted in “portrait” mode were predicted to provide little to no power gain from LRF under real world conditions. Based on these results, modules with LRF on tabbing ribbons would have to be mounted in “landscape” mode to realize a performance advantage. In addition

  17. On High-Order Radiation Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Hagstrom, Thomas

    1995-01-01

    In this paper we develop the theory of high-order radiation boundary conditions for wave propagation problems. In particular, we study the convergence of sequences of time-local approximate conditions to the exact boundary condition, and subsequently estimate the error in the solutions obtained using these approximations. We show that for finite times the Pade approximants proposed by Engquist and Majda lead to exponential convergence if the solution is smooth, but that good long-time error estimates cannot hold for spatially local conditions. Applications in fluid dynamics are also discussed.

  18. Light-Emitting Diodes (LED) for Primary Animal Habitat Lighting in Highly Controlled Environments

    NASA Technical Reports Server (NTRS)

    Winget, C. M.; Syrkin, N.; Heeke, D.; Mele, G.; Holley, D. C.; Dalton, Bonnie P. (Technical Monitor)

    1996-01-01

    Significant alterations in Biological Clock responses have been reported following sidereal time changes (e.g., Jet-lag), and exposure to microgravity (e.g., daytime sleepiness). Additionally, light reduces circulating melatonin (spectral specificity greatest between 450-500 nm). It was hypothesized that LEDs can replace the current light sources used in zero gravity and terrestrial research laboratories because of their small size, low mass, low energy consumption and long functional life. This report evaluates the capacity of LEDs to entrain the circadian system of rats as judged by measurement of overt behavioral circadian rhythms (activity, feeding, drinking). These data were collected in highly controlled environments similar to the shuttle Animal Enclosure Modules. Two groups were compared: control - animals exposed to standard cool-white fluorescent lights, and test - animals exposed to LEDs with a spectral power distribution matching the fluorescent lights. Gross locomotor activity, feeding and drinking frequencies were continuously monitored and stored at 10 minute intervals. Animals were exposed to the following photoperiods: 28 days of 12L:12D, 19 days of 24L:0D and 16 days of 12L:12D. Light intensities tested varied between 0.1 to 100 lux. Rats received food and water ad libitum, and temperature and humidity were controlled throughout the study. The general health status of all rats was acceptable for each day of this study. No incidents of aggressive behavior were observed. Growth, locomotor activity, food and water consumption were comparable for all groups of animals, i.e, the circadian characteristics of the animals under these conditions were comparable. These results indicate that LED arrays are as effective in maintaining circadian rhythm stability as the commonly used cool-white fluorescent light sources. LEDs with their flexible spectrum, low energy requirements and minimal heat production have advantages for some chronopharmacology studies and

  19. Light-Emitting Diodes (LED) for Primary Animal Habitat Lighting in Highly Controlled Environments

    NASA Technical Reports Server (NTRS)

    Winget, C. M.; Syrkin, N.; Heeke, D.; Mele, G.; Holley, D. C.; Dalton, Bonnie P. (Technical Monitor)

    1996-01-01

    Significant alterations in Biological Clock responses have been reported following sidereal time changes (e.g., Jet-lag), and exposure to microgravity (e.g., daytime sleepiness). Additionally, light reduces circulating melatonin (spectral specificity greatest between 450-500 nm). It was hypothesized that LEDs can replace the current light sources used in zero gravity and terrestrial research laboratories because of their small size, low mass, low energy consumption and long functional life. This report evaluates the capacity of LEDs to entrain the circadian system of rats as judged by measurement of overt behavioral circadian rhythms (activity, feeding, drinking). These data were collected in highly controlled environments similar to the shuttle Animal Enclosure Modules. Two groups were compared: control - animals exposed to standard cool-white fluorescent lights, and test - animals exposed to LEDs with a spectral power distribution matching the fluorescent lights. Gross locomotor activity, feeding and drinking frequencies were continuously monitored and stored at 10 minute intervals. Animals were exposed to the following photoperiods: 28 days of 12L:12D, 19 days of 24L:0D and 16 days of 12L:12D. Light intensities tested varied between 0.1 to 100 lux. Rats received food and water ad libitum, and temperature and humidity were controlled throughout the study. The general health status of all rats was acceptable for each day of this study. No incidents of aggressive behavior were observed. Growth, locomotor activity, food and water consumption were comparable for all groups of animals, i.e, the circadian characteristics of the animals under these conditions were comparable. These results indicate that LED arrays are as effective in maintaining circadian rhythm stability as the commonly used cool-white fluorescent light sources. LEDs with their flexible spectrum, low energy requirements and minimal heat production have advantages for some chronopharmacology studies and

  20. Effects of VDT workstation lighting conditions on operator visual workload.

    PubMed

    Lin, Chiuhsiang Joe; Feng, Wen-Yang; Chao, Chin-Jung; Tseng, Feng-Yi

    2008-04-01

    Industrial lighting covers a wide range of different characteristics of working interiors and work tasks. This study investigated the effects of illumination on visual workload in visual display terminal (VDT) workstation. Ten college students (5 males and 5 females) were recruited as participants to perform VDT signal detection tasks. A randomized block design was utilized with four light colors (red, blue, green and white), two ambient illumination levels (20 lux and 340 lux), with the subject as the block. The dependent variables were the change of critical fusion frequency (CFF), visual acuity, reaction time of targets detection, error rates, and rating scores in a subjective questionnaire. The study results showed that both visual acuity and the subjective visual fatigue were significantly affected by the color of light. The illumination had significant effect on CFF threshold change and reaction time. Subjects prefer to perform VDT task under blue and white lights than green and red. Based on these findings, the study discusses and suggests ways of color lighting and ambient illumination to promote operators' visual performance and prevent visual fatigue effectively.

  1. Stable motor cortex excitability in red and green lighting conditions.

    PubMed

    Langguth, Berthold; Eichhammer, Peter; Pickert, Karin; Frank, Ulrike; Perna, Martin; Landgrebe, Michael; Frick, Ulrich; Hajak, Goeran; Sand, Philipp

    2009-08-21

    Illumination science has long established effects of coloured light on emotional state, cognitive performance, plus tactile, gustatory and olfactory perception. To explore the neurobiological mechanisms underlying these crossmodal phenomena, cortical excitability was addressed by single and paired-pulse transcranial magnetic stimulation (TMS) in 23 men with normal colour vision, and in 10 subjects with red-green blindness. Using a sequential challenge, excitability measures were recorded at baseline and during exposure to either red or green light. Dichromacy did not predict any of the electrophysiological parameters under study regardless of the spectral paradigm. In both dichromats and trichromats, red and green illumination did not induce any significant effects on resting motor threshold, short intracortical inhibition, intracortical facilitation and cortical silent periods. Our results suggest that motor cortex excitability as assessed by TMS is not sensitive to the modulatory effects of context-independent red and green light.

  2. Analysis of the injury severity of crashes by considering different lighting conditions on two-lane rural roads.

    PubMed

    Jafari Anarkooli, A; Hadji Hosseinlou, M

    2016-02-01

    Many studies have examined different factors contributing to the injury severity of crashes; however, relatively few studies have focused on the crashes by considering the specific effects of lighting conditions. This research investigates lighting condition differences in the injury severity of crashes using 3-year (2009-2011) crash data of two-lane rural roads of the state of Washington. Separate ordered-probit models were developed to predict the effects of a set of factors expected to influence injury severity in three lighting conditions; daylight, dark, and dark with street lights. A series of likelihood ratio tests were conducted to determine if these lighting condition models were justified. The modeling results suggest that injury severity in specific lighting conditions are associated with contributing factors in different ways, and that such differences cannot be uncovered by focusing merely on one aggregate model. Key differences include crash location, speed limit, shoulder width, driver action, and three collision types (head-on, rear-end, and right-side impact collisions). This paper highlights the importance of deploying street lights at and near intersections (or access points) on two-lane rural roads because injury severity highly increases when crashes occur at these points in dark conditions. Copyright © 2016 Elsevier Ltd and National Safety Council. All rights reserved.

  3. Photocathodes for High Repetition Rate Light Sources

    SciTech Connect

    Ben-Zvi, Ilan

    2014-04-20

    This proposal brought together teams at Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL) and Stony Brook University (SBU) to study photocathodes for high repetition rate light sources such as Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). Below details the Principal Investigators and contact information. Each PI submits separately for a budget through his corresponding institute. The work done under this grant comprises a comprehensive program on critical aspects of the production of the electron beams needed for future user facilities. Our program pioneered in situ and in operando diagnostics for alkali antimonide growth. The focus is on development of photocathodes for high repetition rate Free Electron Lasers (FELs) and Energy Recovery Linacs (ERLs), including testing SRF photoguns, both normal-­conducting and superconducting. Teams from BNL, LBNL and Stony Brook University (SBU) led this research, and coordinated their work over a range of topics. The work leveraged a robust infrastructure of existing facilities and the support was used for carrying out the research at these facilities. The program concentrated in three areas: a) Physics and chemistry of alkali-­antimonide cathodes (BNL – LBNL) b) Development and testing of a diamond amplifier for photocathodes (SBU -­ BNL) c) Tests of both cathodes in superconducting RF photoguns (SBU) and copper RF photoguns (LBNL) Our work made extensive use of synchrotron radiation materials science techniques, such as powder-­ and single-­crystal diffraction, x-­ray fluorescence, EXAFS and variable energy XPS. BNL and LBNL have many complementary facilities at the two light sources associated with these laboratories (NSLS and ALS, respectively); use of these will be a major thrust of our program and bring our understanding of these complex materials to a new level. In addition, CHESS at Cornell will be used to continue seamlessly throughout the NSLS dark period and

  4. Isorefractive high internal phase emulsion organogels for light induced reactions.

    PubMed

    Zhang, Tao; Guo, Qipeng

    2016-03-25

    Isorefractive high internal phase emulsion (HIPE) organogels have been fabricated and investigated for light induced reactions. High transparency facilitates both the UV and visible light induced reactions within HIPE organogels. Transparent HIPE organogels are advantageous for light induced polymerizations, accelerating such polymerizations and enabling the preparation of large polyHIPE monoliths.

  5. National Term and Condition for Light Refreshments and Meals

    EPA Pesticide Factsheets

    Unless the event(s) are specified in the approved workplan, the recipient agrees to obtain prior approval from EPA for the use of grant funds for light refreshments and/or meals served at meetings, conferences, training workshops, and outreach activities.

  6. HELIX: The High Energy Light Isotope Experiment

    NASA Astrophysics Data System (ADS)

    Musser, Jim

    This is the lead proposal for a new suborbital program, HELIX (High-Energy Light Isotope eXperiment), designed to make measurements of the isotopic composition of light cosmic-ray nuclei from ~200 MeV/nuc to ~10 GeV/nuc. Past measurements of this kind have provided profound insights into the nature and origin of cosmic rays, revealing, for instance, information on acceleration and confinement time scales, and exposing some conspicuous discrepancies between solar and cosmic-ray abundances. The most detailed information currently available comes from the ACE/CRIS mission, but is restricted to energies below a few 100 MeV/nuc. HELIX aims at extending this energy range by over an order of magnitude, where, in most cases, no measurements of any kind exist, and where relativistic time dilation affects the apparent lifetime of radioactive clock nuclei. The HELIX measurements will provide essential information for understanding the propagation history of cosmic rays in the galaxy. This is crucial for properly interpreting several intriguing anomalies reported in recent cosmic-ray measurements, pertaining to the energy spectra of protons, helium, and heavier nuclei, and to the anomalous rise in the positron fraction at higher energy. HELIX employs a high-precision magnet spectrometer to provide measurements which are not achievable by any current or planned instrument. The superconducting magnet originally used for the HEAT payload in five successful high-altitude flights will be combined with state-of-the-art detectors to measure the charge, time-of-flight, magnetic rigidity, and velocity of cosmic-ray particles with high precision. The instrumentation includes plastic scintillators, silicon-strip detectors repurposed from Fermilab's CDF detector, a high-performance gas drift chamber, and a ring-imaging Cherenkov counter employing aerogel radiators and silicon photomultipliers. To reduce cost and technical risk, the HELIX program will be structured in two stages. The first

  7. HELIX: The High Energy Light Isotope Experiment

    NASA Astrophysics Data System (ADS)

    Wakely, Scott

    This is the lead proposal for a new suborbital program, HELIX (High-Energy Light Isotope eXperiment), designed to make measurements of the isotopic composition of light cosmic-ray nuclei from ~200 MeV/nuc to ~10 GeV/nuc. Past measurements of this kind have provided profound insights into the nature and origin of cosmic rays, revealing, for instance, information on acceleration and confinement time scales, and exposing some conspicuous discrepancies between solar and cosmic-ray abundances. The most detailed information currently available comes from the ACE/CRIS mission, but is restricted to energies below a few 100 MeV/nuc. HELIX aims at extending this energy range by over an order of magnitude, where, in most cases, no measurements of any kind exist, and where relativistic time dilation affects the apparent lifetime of radioactive clock nuclei. The HELIX measurements will provide essential information for understanding the propagation history of cosmic rays in the galaxy. This is crucial for properly interpreting several intriguing anomalies reported in recent cosmic-ray measurements, pertaining to the energy spectra of protons, helium, and heavier nuclei, and to the anomalous rise in the positron fraction at higher energy. HELIX employs a high-precision magnet spectrometer to provide measurements which are not achievable by any current or planned instrument. The superconducting magnet originally used for the HEAT payload in five successful high-altitude flights will be combined with state-of-the-art detectors to measure the charge, time-of-flight, magnetic rigidity, and velocity of cosmic-ray particles with high precision. The instrumentation includes plastic scintillators, silicon-strip detectors repurposed from Fermilab's CDF detector, a high-performance gas drift chamber, and a ring-imaging Cherenkov counter employing aerogel radiators and silicon photomultipliers. To reduce cost and technical risk, the HELIX program will be structured in two stages. The first

  8. Organic light-emitting diodes: High-throughput virtual screening

    NASA Astrophysics Data System (ADS)

    Hirata, Shuzo; Shizu, Katsuyuki

    2016-10-01

    Computer networks, trained with data from delayed-fluorescence materials that have been successfully used in organic light-emitting diodes, facilitate the high-speed prediction of good emitters for display and lighting applications.

  9. Light Initiated High Explosives (LIHE) Test Technique and Capabilities

    NASA Astrophysics Data System (ADS)

    Covert, Timothy

    2009-06-01

    The Light Initiated High Explosives (LIHE) test facility has been re-established and chartered to impart impulsive loads to a variety of targets. This loading is achieved through the detonation of a primary explosive applied directly to the target surface using a robotic spraying system. Using light as the initiating mechanism ensures virtually simultaneous loading. Uniform, discontinuous, or graded explosive loading conditions are achievable over complex shapes with the LIHE process. This direct detonation technique is a demonstrated capability at the LIHE facility. Test results will be presented. In addition to the direct detonation technique, the LIHE facility is developing the capability to explosively accelerate a thin flyer plate to impact various test targets. This explosively accelerated flyer plate (X-Flyer) will enable pressure control during impulsive loading. By controlling flyer density (material), thickness, velocity, and acceleration gap, the impact pressure amplitude and pulse duration can be controlled. Similar to the direct detonation technique, a primary explosive is robotically sprayed onto the flyer plate and subsequently detonated using an intense flash of light. Through the control of the explosive deposition and flyer gap, virtually simultaneous impact is achievable for either uniform or graded loading conditions. X-Flyer test results will be presented.

  10. High flexibility, noncollapsing light weight hose

    SciTech Connect

    Williams, D.A.

    1991-02-01

    This invention relates generally to a high-flexibility, light weight, noncollapsing hose and more particularly to such a hose having a large size and particularly useful as equipment draining a radioactively contaminated fluid through a noncontaiminated, isolated and restricted space with high confidence against kinking, collapse, or leaking even with large relative motion between the inlet and outlet ends of the hose. In the operation of nuclear facilities, such as nuclear reactors, processing plants for nuclear fuels and related materials, and chemical processing plants, for example, it is necessary to handle radioactively and/or chemically contaminated fluids which in many instances must be conducted, such as for draining purposes, through a noncontaminated, isolated area. Conduction of such contaminated fluids through uncontaminated environments in practice requires the highest confidence that the hose will not kink, collapse, break, or leak even though the hose may be subject to a large amount of motion relative to the inlet and outlet ends of the hose. Any such breaking, or leaking would result in undesirable contamination of the area through which the hose passes which could result in major damage and/or in the requirement to shut down the operation for cleanup and decontamination processing of the area. Additional problems are also encountered in processing plants for contaminated materials due to the fact that hoses conducting the contaminated liquids or gases pass through inaccessible, restricted spaces requiring extreme flexibility in the hose, but with the assurance that the hose will neither kink nor collapse to close off the flow.

  11. High Efficient OLEDs and Their Application to Lighting

    NASA Astrophysics Data System (ADS)

    Komoda, Takuya; Ide, Nobuhiro; Kido, Junji

    Organic Light Emitting Diode (OLED) is one of the strongest candidates for the next generation solid state lighting alternative to conventional incandescent bulbs and fluorescent lamps. There are still a lot of issues to overcome in order to commercialize OLED lighting, but a number of elemental technologies indispensable for OLED lighting such as high efficiency, long lifetime at high luminance and large area uniform emission have been developed.

  12. Optogenetics, the intersection between physics and neuroscience: light stimulation of neurons in physiological conditions.

    PubMed

    Deng, Wei; Goldys, Ewa M; Farnham, Melissa M J; Pilowsky, Paul M

    2014-12-01

    Neuronal stimulation by light is a novel approach in the emerging field of optogenetics, where genetic engineering is used to introduce light-activated channels. However, light is also capable of stimulating neurons even in the absence of genetic modifications through a range of physical and biological mechanisms. As a result, rigorous design of optogenetic experiments needs to take note of alternative and parallel effects of light illumination of neuronal tissues. Thus all matters relating to light penetration are critical to the development of studies using light-activated proteins. This paper discusses ways to quantify light, light penetration in tissue, as well as light stimulation of neurons in physiological conditions. We also describe the direct effect of light on neurons investigated at different sites. Copyright © 2014 the American Physiological Society.

  13. Vacuum fluctuations and the conditional homodyne detection of squeezed light

    NASA Astrophysics Data System (ADS)

    Carmichael, H. J.; Nha, Hyunchul

    2004-08-01

    Conditional homodyne detection of quadrature squeezing is compared with standard nonconditional detection. Whereas the latter identifies nonclassicality in a quantitative way, as a reduction of the noise power below the shot noise level, conditional detection makes a qualitative distinction between vacuum state squeezing and squeezed classical noise. Implications of this comparison for the realistic interpretation of vacuum fluctuations (stochastic electrodynamics) are discussed.

  14. High Extraction Phosphors for Solid State Lighting

    SciTech Connect

    Summers, Chris; Menkara, Hisham; Wagner, Brent

    2011-09-01

    We have developed high-index, high efficiency bulk luminescent materials and novel nano-sized phosphors for improved solid-state white LED lamps. These advances can potentially contribute to reducing the loss in luminous efficiencies due to scattering, re-absorption, and thermal quenching. The bulk and nanostructured luminescent materials investigated are index matched to GaN and have broad and size-tunable absorption bands, size and impurity tuned emission bands, size-driven elimination of scattering effects, and a separation between absorption and emission bands. These innovations were accomplished through the use of novel synthesis techniques suitable for high volume production for LED lamp applications. The program produced a full-color set of high quantum yield phosphors with high chemical stability. In the bulk phosphor study, the ZnSeS:Cu,Ag phosphor was optimized to achieve >91% efficiency using erbium (Er) and other activators as sensitizers. Detailed analysis of temperature quenching effects on a large number of ZnSeS:Cu,Ag,X and strontium- and calcium-thiogallate phosphors lead to a breakthrough in the understanding of the anti-quenching behavior and a physical bandgap model was developed of this phenomena. In a follow up to this study, optimized phosphor blends for high efficiency and color performance were developed and demonstrated a 2-component phosphor system with good white chromaticity, color temperature, and high color rendering. By extending the protocols of quantum dot synthesis, large nanocrystals, greater than 20 nm in diameter were synthesized and exhibited bulk-like behavior and blue light absorption. The optimization of ZnSe:Mn nanophosphors achieved ~85% QE The limitations of core-shell nanocrystal systems were addressed by investigating alternative deltadoped structures. To address the manufacturability of these systems, a one-pot manufacturing protocol was developed for ZnSe:Mn nanophosphors. To enhance the stability of these material

  15. Alleviation of high light-induced photoinhibition in cyanobacteria by artificially conferred biosilica shells.

    PubMed

    Xiong, Wei; Yang, Zhou; Zhai, Hailei; Wang, Guangchuan; Xu, Xurong; Ma, Weimin; Tang, Ruikang

    2013-09-04

    Bioinspired by diatoms, biomimetic silicification confers an artificial shell on cyanobacteria to alleviate photoinhibition; thus, the photosynthesis of the resulting cyanobacteria@SiO2 becomes more efficient under high light conditions.

  16. A squeezed light source operated under high vacuum

    PubMed Central

    Wade, Andrew R.; Mansell, Georgia L.; Chua, Sheon S. Y.; Ward, Robert L.; Slagmolen, Bram J. J.; Shaddock, Daniel A.; McClelland, David E.

    2015-01-01

    Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments. PMID:26657616

  17. Lighting and Nurses at Medical-Surgical Units: Impact of Lighting Conditions on Nurses' Performance and Satisfaction.

    PubMed

    Hadi, Khatereh; DuBose, Jennifer R; Ryherd, Erica

    2016-04-01

    This study investigates the perception of nurses about their lighting environment at medical-surgical hospital units in order to understand areas of improvement for lighting at these units. The bulk of the research about nurses and lighting is focused on nighttime nursing, exploring the disruptions of nurses' circadian rhythm and maintaining alertness. The understanding of nurses' perception about lighting and its impact on nurses' task performance and patient examination remains imprecise. This study used an online survey to ask a set of questions about lighting in medical-surgical units at five key locations including centralized nurse stations, decentralized nurse stations (DCNS), patient bedsides, patient bathrooms, and corridors from 393 survey participants. It then explored the survey findings in more depth through conducting focus groups with eight volunteer nurses. Lighting conditions at patient besides and DCNSs were significantly less desirable for nurses compared to other locations. A significant relationship between nurses' access to lighting controls (switches and dimmers) and satisfaction about the lighting environment was found. No significant relationship was observed between the individual characteristics of nurses (such as age, years of experience, etc.) and findings of this study. Thoughtful design of the lighting environment can improve nurses' satisfaction and perception about their working environment. © The Author(s) 2015.

  18. Conditional homodyne detection of light with squeezed quadrature fluctuations

    SciTech Connect

    Vines, Justin; Vyas, Reeta; Singh, Surendra

    2006-08-15

    We discuss the detection of field quadrature fluctuations in conditional homodyne detection experiments and possible sources of error in such an experiment. We also present modifications to these experiments to help eliminate such errors and extend their range of applicability.

  19. Natural light-micro aerobic condition for PSB wastewater treatment: a flexible, simple, and effective resource recovery wastewater treatment process.

    PubMed

    Lu, Haifeng; Han, Ting; Zhang, Guangming; Ma, Shanshan; Zhang, Yuanhui; Li, Baoming; Cao, Wei

    2017-03-13

    Photosynthetic bacteria (PSB) have two sets of metabolic pathways. They can degrade pollutants through light metabolic under light-anaerobic or oxygen metabolic pathways under dark-aerobic conditions. Both metabolisms function under natural light-microaerobic condition, which demands less energy input. This work investigated the characteristics of PSB wastewater treatment process under that condition. Results showed that PSB had very strong adaptability to chemical oxygen demand (COD) concentration; with F/M of 5.2-248.5 mg-COD/mg-biomass, the biomass increased three times and COD removal reached above 91.5%. PSB had both advantages of oxygen metabolism in COD removal and light metabolism in resource recovery under natural light-microaerobic condition. For pollutants' degradation, COD, total organic carbon, nitrogen, and phosphorus removal reached 96.2%, 91.0%, 70.5%, and 92.7%, respectively. For resource recovery, 74.2% of C in wastewater was transformed into biomass. Especially, coexistence of light and oxygen promote N recovery ratio to 70.9%, higher than with the other two conditions. Further, 93.7% of N-removed was synthesized into biomass. Finally, CO2 emission reduced by 62.6% compared with the traditional process. PSB wastewater treatment under this condition is energy-saving, highly effective, and environment friendly, and can achieve pollution control and resource recovery.

  20. Novel Characteristics of Photodamage to PSII in a High-Light-Sensitive Symbiodinium Phylotype.

    PubMed

    Karim, Widiastuti; Seidi, Azadeh; Hill, Ross; Chow, Wah S; Minagawa, Jun; Hidaka, Michio; Takahashi, Shunichi

    2015-06-01

    Dinoflagellates from the genus Symbiodinium form symbiotic relationships with many marine invertebrates, including reef-building corals. Symbiodinium is genetically diverse, and acquiring suitable Symbiodinium phylotypes is crucial for the host to survive in habitat environments, such as high-light conditions. The sensitivity of Symbiodinium to high light differs among Symbiodinium phylotypes, but the mechanism that controls light sensitivity has not yet been fully resolved. In the present study using high-light-tolerant and -sensitive Symbiodinium phylotypes, we examined what determines sensitivity to high light. In growth experiments under different light intensities, Symbiodinium CS-164 (clade B1) and CCMP2459 (clade B2) were identified as high-light-tolerant and -sensitive phylotypes, respectively. Measurements of the maximum quantum yield of photosystem II (PSII) and the maximum photosynthetic oxygen production rate after high-light exposure demonstrated that CCMP2459 is more sensitive to photoinhibition of PSII than CS-164, and tends to lose maximum photosynthetic activity faster. Measurement of photodamage to PSII under light of different wavelength ranges demonstrated that PSII in both Symbiodinium phylotypes was significantly more sensitive to photodamage under shorter wavelength regions of light spectra (<470 nm). Importantly, PSII in CCMP2459, but not CS-164, was also sensitive to photodamage under the regions of light spectra around 470-550 and 630-710 nm, where photosynthetic antenna proteins of Symbiodinium have light absorption peaks. This finding indicates that the high-light-sensitive CCMP2459 has an extra component of photodamage to PSII, resulting in higher sensitivity to high light. Our results demonstrate that sensitivity of PSII to photodamage differs among Symbiodinium phylotypes and this determines their sensitivity to high light.

  1. Planar light bullets under conditions of second-harmonic generation

    NASA Astrophysics Data System (ADS)

    Sazonov, Sergey V.; Mamaikin, Mikhail S.; Komissarova, Maria V.; Zakharova, Irina G.

    2017-08-01

    We study solutions to second-harmonic-generation equations in two-dimensional media with anomalous dispersion. The analytical solution is obtained in an approximate form of the planar spatiotemporal two-component soliton by means of the averaged Lagrangian method. It is shown that a decrease in the amplitudes of both soliton components and an increase in the value of the transverse coordinate are accompanied by an increase in their temporal duration. Within this variational approach, we have managed to find a stability criterion for the light bullet and a period of oscillations of soliton parameters. Then, we use the obtained form as an initial configuration to carry out the direct numerical simulation of soliton dynamics. We demonstrate stable propagation of spatiotemporal solitons undergoing small oscillations predicted analytically for a long distance. The formation of a two-component light bullet is shown when we launch a pulse only at the fundamental frequency. In addition, we investigate the phase and group-velocity mismatch effects on the propagation of pulses.

  2. High-accuracy Propagation of Light Rays

    NASA Astrophysics Data System (ADS)

    Teyssandier, Pierre

    2009-05-01

    We recall the relativistic definition of the angle between a light ray and a given direction or between two light rays as measured by an observer moving with a given unit 4-velocity. Then we present a review of the different methods currently used to determine the deflection of light in a gravitational field. In almost all the works devoted to this problem, the deflection of light is determined by integrating the differential equations of null geodesics of the metric. For example, this procedure is the basis of the different models proposed to exploit the data furnished by GAIA. However, very different approaches have been developed in recent years. These new procedures are particularly convenient for treating the cases where both the source of the ray and the observer are located at a finite distance. Moreover, these alternative approaches avoid integrating the geodesic equations. After a brief discussion of the advantages and disadvantages of each method, we summarize some recent results enabling new tests of relativity, especially the bending of light due to the mass-multipoles of a giant planet.

  3. LIGHT SCATTERING: Fast path-integration technique in simulation of light propagation through highly scattering objects

    NASA Astrophysics Data System (ADS)

    Voronov, Aleksandr V.; Tret'yakov, Evgeniy V.; Shuvalov, Vladimir V.

    2004-06-01

    Based on the path-integration technique and the Metropolis method, the original calculation scheme is developed for solving the problem of light propagation through highly scattering objects. The elimination of calculations of 'unnecessary' realisations and the phenomenological description of processes of multiple small-angle scattering provided a drastic increase (by nine and more orders of magnitude) in the calculation rate, retaining the specific features of the problem (consideration of spatial inhomogeneities, boundary conditions, etc.). The scheme allows one to verify other fast calculation algorithms and to obtain information required to reconstruct the internal structure of highly scattering objects (of size ~1000 scattered lengths and more) by the method of diffusion optical tomography.

  4. Delineation of the southern elephant seal's main foraging environments defined by temperature and light conditions

    NASA Astrophysics Data System (ADS)

    Vacquié-Garcia, Jade; Guinet, Christophe; Laurent, Cécile; Bailleul, Frédéric

    2015-03-01

    Changes in marine environments, induced by the global warming, are likely to influence the prey field distribution and consequently the foraging behaviour and the distribution of top marine predators. Thanks to bio-logging, the simultaneous measurements of fine-scale foraging behaviors and oceanographic parameters by predators allow characterizing their foraging environments and provide insights into their prey distribution. In this context, we propose to delimit and to characterize the foraging environments of a marine predator, the Southern Elephant Seal (SES). To do so, the relationship between oceanographic factors and prey encounter events (PEE) was investigated in 12 females SES from Kerguelen Island simultaneously equipped with accelerometers and with a range of physical sensors (temperature, light and depth). PEEs were assessed from the accelerometer data at high spatio-temporal precision while the physical sensors allowed the continuous monitoring of environmental conditions encountered by the SES when diving. First, visited and foraging environments were distinguished according to the oceanographic conditions encountered in the absence and in presence of PEE. Then, a hierarchical classification of the physical parameters recorded during PEEs led to the distinction of five different foraging environments. These foraging environments were structured according to the main frontal systems of the SO. One was located north to the subantarctic front (SAF) and characterized by high temperature and depth, and low light levels. Another, characterized by intermediate levels of temperature, light and depth, was located between the SAF and the polar front (PF). And finally, the last three environments were all found south to the PF and, characterized by low temperature but highly variable depth and light levels. The large physical and/or spatial differences found between these environments suggest that, depending on the location, different prey communities are

  5. Loss of alpha-tocopherol in tobacco plants with decreased geranylgeranyl reductase activity does not modify photosynthesis in optimal growth conditions but increases sensitivity to high-light stress.

    PubMed

    Grasses, T; Grimm, B; Koroleva, O; Jahns, P

    2001-08-01

    The enzyme geranylgeranyl reductase (CHL P) catalyses the reduction of geranylgeranyl diphosphate to phytyl diphosphate in higher-plant chloroplasts and provides phytol for both chlorophyll (Chl) and tocopherol synthesis. The reduction in CHL P activity in transgenic tobacco (Nicotiana tabacum L.) plants is accompanied by the reduction in total Chl and tocopherol content and the accumulation of geranylgeranylated Chl (ChlGG). The photosynthetic performance and the susceptibility to photo-oxidative stress have been investigated in these transgenic plants. The reduced total Chl content in Chl P antisense plants resulted in the reduction of electron transport chains per leaf area without a concomitant effect on the stoichiometry, composition and activity of both photosystems. However, Chl P antisense plants were much more sensitive to light stress. Analyses of Chl fluorescence quenching indicated an increased photoinhibitory quenching at the expense of the pH-dependent fluorescence quenching after short illumination (15 min) at moderate light intensities. Prolonged illumination (up to 1 h) at saturating light intensities induced an increased photoinactivation from which the Chl P antisense plants could not recover or could only partially recover during a subsequent low light phase. Our data imply that the presence of ChlGG has no influence on harvesting and transfer of light energy in either photosystem. However, the reduced tocopherol content of the thylakoid membrane is a limiting factor for defensive reactions to photo-oxidative stress.

  6. Denoising Algorithm for the Pixel-Response Non-Uniformity Correction of a Scientific CMOS Under Low Light Conditions

    NASA Astrophysics Data System (ADS)

    Hu, Changmiao; Bai, Yang; Tang, Ping

    2016-06-01

    We present a denoising algorithm for the pixel-response non-uniformity correction of a scientific complementary metal-oxide-semiconductor (CMOS) image sensor, which captures images under extremely low-light conditions. By analyzing the integrating sphere experimental data, we present a pixel-by-pixel flat-field denoising algorithm to remove this fixed pattern noise, which occur in low-light conditions and high pixel response readouts. The response of the CMOS image sensor imaging system to the uniform radiance field shows a high level of spatial uniformity after the denoising algorithm has been applied.

  7. High-resolution record of sea ice conditions in Fram Strait sheds new light on ice-ocean interactions and climate variability during the late glacial and Termination 1

    NASA Astrophysics Data System (ADS)

    Müller, Juliane; Stein, Ruediger

    2014-05-01

    Abrupt shifts in the palaeoceanographic setting in the subpolar North Atlantic and a hence significant climate variability characterised the transition from last glacial to deglacial and current interglacial conditions. Knowledge about the crucial role of sea ice coverage during these rapid climate reversals, however, is still limited. Herein we present a high-resolution reconstruction of the sea ice conditions that prevailed in eastern Fram Strait - the only deepwater passage permitting a substantial exchange of water and ice masses between the Arctic and the Atlantic Ocean - during the late glacial and deglacial period (i.e. from 29 ka to 9 ka BP). The joint analysis of the sea ice biomarker IP25 (Belt et al., 2007) and phytoplankton derived biomarkers allows to distinguish between different sea ice conditions and we further provide an even semi-quantitative assessment of the sea ice cover by means of the PIP25 index (Müller et al., 2011). Information about relative sea surface temperature changes is derived from the so-called DIP25 index (Cabedo-Sanz et al., 2013; Fahl & Stein, 2012). Importantly, the exceptional high temporal resolution of the studied sediment core permits the identification of a hitherto unknown variability in the sea ice coverage throughout the late glacial, which finally culminates in a permanent sea ice cover at the end of the Last Glacial Maximum (LGM). We suggest that the heat flow to the Nordic Seas during this critical time interval of Northern Hemisphere ice-sheet growth was rather pulse-like than continuous as is commonly assumed. This new observation of late glacial short-term fluctuations in the sea ice cover has considerable implications for palaeoceanographic proxy and model studies that focus on the LGM. Furthermore, we consider that the abrupt breakup of the perennial sea ice cover in Fram Strait at about 18 ka BP directly contributed to the weakening of the Atlantic Meridional Overturning Circulation (AMOC) during Heinrich

  8. Photosystem II cycle activity and alternative electron transport in the diatom Phaeodactylum tricornutum under dynamic light conditions and nitrogen limitation.

    PubMed

    Wagner, Heiko; Jakob, Torsten; Lavaud, Johann; Wilhelm, Christian

    2016-05-01

    Alternative electron sinks are an important regulatory mechanism to dissipate excessively absorbed light energy particularly under fast changing dynamic light conditions. In diatoms, the cyclic electron transport (CET) around Photosystem II (PS II) is an alternative electron transport pathway (AET) that contributes to avoidance of overexcitation under high light illumination. The combination of nitrogen limitation and high-intensity irradiance regularly occurs under natural conditions and is expected to force the imbalance between light absorption and the metabolic use of light energy. The present study demonstrates that under N limitation, the amount of AET and the activity of CETPSII in the diatom Phaeodactylum tricornutum were increased. Thereby, the activity of CETPSII was linearly correlated with the amount of AET rates. It is concluded that CETPSII significantly contributes to AET in P. tricornutum. Surprisingly, CETPSII was found to be activated already at the end of the dark period under N-limited conditions. This coincided with a significantly increased degree of reduction of the plastoquinone (PQ) pool. The analysis of the macromolecular composition of cells of P. tricornutum under N-limited conditions revealed a carbon allocation in favor of carbohydrates during the light period and their degradation during the dark phase. A possible linkage between the activity of CETPSII and degree of reduction of the PQ pool on the one side and the macromolecular changes on the other is discussed.

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

    PubMed

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

    2017-01-01

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

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

    PubMed Central

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

    2017-01-01

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

  11. Truck-involved crashes injury severity analysis for different lighting conditions on rural and urban roadways.

    PubMed

    Uddin, Majbah; Huynh, Nathan

    2017-11-01

    This paper investigates factors affecting injury severity of crashes involving trucks for different lighting conditions on rural and urban roadways. It uses 2009-2013 Ohio crash data from the Highway Safety Information System. The explanatory factors include the occupant, vehicle, collision, roadway, temporal and environmental characteristics. Six separate mixed logit models were developed considering three lighting conditions (daylight, dark, and dark-lighted) on two area types (rural and urban). A series of log-likelihood ratio tests were conducted to validate that these six separate models by lighting conditions and area types are warranted. The model results suggest major differences in both the combination and the magnitude of impact of variables included in each model. Some variables were significant only in one lighting condition but not in other conditions. Similarly, some variables were found to be significant in one area type but not in other area type. These differences show that the different lighting conditions and area types do in fact have different contributing effects on injury severity in truck-involved crashes, further highlighting the importance of examining crashes based on lighting conditions on rural and urban roadways. Age and gender of occupant (who is the most severely injured in a crash), truck types, AADT, speed, and weather condition were found to be factors that have significantly different levels of impact on injury severity in truck-involved crashes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Dementia screening in light of the diversity of the condition.

    PubMed

    Gualtieri, C Thomas

    2004-01-01

    Dementia is a general term, not a specific diagnosis. There are many different causes of dementia, and the different etiologies are associated with different neuropsychological profiles. This complicates the problem of dementia screening. Detection of dementing conditions at the earliest possible stage requires batteries of tests, rather than a single test. The cognitive domains that must be addressed include the following: visual and verbal memory, sustained attention and complex attention, working memory, processing speed, reaction time, psychomotor speed and executive function.

  13. Effect of lighting conditions on brain network complexity associated with response learning.

    PubMed

    Fidalgo, Camino; Conejo, Nélida M; González-Pardo, Héctor; Arias, Jorge L

    2013-10-25

    Several studies have reported the brain regions involved in response learning. However, there is discrepancy regarding the lighting conditions in the experimental setting (i.e. under dark or light conditions). In this regard, it would be relevant to know if the presence/absence of visual cues in the environment has any effect in the brain networks involved in a response learning task. Animals were trained in a water T-maze under two different lighting conditions (light versus dark). All subjects reached the learning criterion of 80% correct arm choices. Quantitative cytochrome oxidase (CO) histochemistry was used as a metabolic brain mapping technique. Our results show that the ventral hippocampus and the parietal cortex are associated with the acquisition of a response learning task regardless of lighting conditions. In addition, when the same task is run in the dark, widespread recruitment of structures involving cortical, limbic and striatal regions was found.

  14. Evaluation of Different Light Conditions in the Working Environment for Handling Photosensitive and Thermolabile Compounds.

    PubMed

    Hernandez Duran, Tania; Ravela, Neel; Sanchez Rivero, Sandra; De Jesus Castro Sandoval, Teresita; Hoogmartens, Jos; Pendela, Murali

    2015-01-01

    Lighting in the working environment plays a significant role on the degree of degradation of photosensitive, thermolabile compounds and on working efficiency. Light emitting diodes (LEDs) are semiconductor light emitting devices that are promising artificial light sources with easy modulation of light wave signals and are also known for low heat generation. Therefore, the effect of polychromatic LED light was tested in the working environment using the drug compounds montelukast, nifedipine, and clavulanic acid, which are known to be photosensitive or thermolabile. As a control, other lighting sources like a sodium lamp, a classic (incandescent, tungsten) lamp, and indirect sunlight were also used in this study. All the experiments were carried out with methanolic solutions at room temperature. An Acquity UPLC/MS/MS system was used for quantification of the main analytes and degradation products. Under the tested conditions, LED lighting proved to be more suitable for handling photosensitive and thermolabile compounds.

  15. High extraction efficiency ultraviolet light-emitting diode

    DOEpatents

    Wierer, Jonathan; Montano, Ines; Allerman, Andrew A.

    2015-11-24

    Ultraviolet light-emitting diodes with tailored AlGaN quantum wells can achieve high extraction efficiency. For efficient bottom light extraction, parallel polarized light is preferred, because it propagates predominately perpendicular to the QW plane and into the typical and more efficient light escape cones. This is favored over perpendicular polarized light that propagates along the QW plane which requires multiple, lossy bounces before extraction. The thickness and carrier density of AlGaN QW layers have a strong influence on the valence subband structure, and the resulting optical polarization and light extraction of ultraviolet light-emitting diodes. At Al>0.3, thinner QW layers (<2.5 nm are preferred) result in light preferentially polarized parallel to the QW plane. Also, active regions consisting of six or more QWs, to reduce carrier density, and with thin barriers, to efficiently inject carriers in all the QWs, are preferred.

  16. High-Efficiency Nitride-Base Photonic Crystal Light Sources

    SciTech Connect

    James Speck; Evelyn Hu; Claude Weisbuch; Yong-Seok Choi; Kelly McGroddy; Gregor Koblmuller; Elison Matioli; Elizabeth Rangel; Fabian Rol; Dobri Simeonov

    2010-01-31

    The research activities performed in the framework of this project represent a major breakthrough in the demonstration of Photonic Crystals (PhC) as a competitive technology for LEDs with high light extraction efficiency. The goals of the project were to explore the viable approaches to manufacturability of PhC LEDS through proven standard industrial processes, establish the limits of light extraction by various concepts of PhC LEDs, and determine the possible advantages of PhC LEDs over current and forthcoming LED extraction concepts. We have developed three very different geometries for PhC light extraction in LEDs. In addition, we have demonstrated reliable methods for their in-depth analysis allowing the extraction of important parameters such as light extraction efficiency, modal extraction length, directionality, internal and external quantum efficiency. The information gained allows better understanding of the physical processes and the effect of the design parameters on the light directionality and extraction efficiency. As a result, we produced LEDs with controllable emission directionality and a state of the art extraction efficiency that goes up to 94%. Those devices are based on embedded air-gap PhC - a novel technology concept developed in the framework of this project. They rely on a simple and planar fabrication process that is very interesting for industrial implementation due to its robustness and scalability. In fact, besides the additional patterning and regrowth steps, the process is identical as that for standard industrially used p-side-up LEDs. The final devices exhibit the same good electrical characteristics and high process yield as a series of test standard LEDs obtained in comparable conditions. Finally, the technology of embedded air-gap patterns (PhC) has significant potential in other related fields such as: increasing the optical mode interaction with the active region in semiconductor lasers; increasing the coupling of the incident

  17. Quality control of PSII: behavior of PSII in the highly crowded grana thylakoids under excessive light.

    PubMed

    Yamamoto, Yasusi; Kai, Suguru; Ohnishi, Atsuki; Tsumura, Nodoka; Ishikawa, Tomomi; Hori, Haruka; Morita, Noriko; Ishikawa, Yasuo

    2014-07-01

    The grana thylakoids of higher plant chloroplasts are crowded with PSII and the associated light-harvesting complexes (LHCIIs). They constitute supercomplexes, and often form semi-crystalline arrays in the grana. The crowded condition of the grana may be necessary for efficient trapping of excitation energy by LHCII under weak light, but it might hinder proper movement of LHCII necessary for reversible aggregation of LHCII in the energy-dependent quenching of Chl fluorescence under moderate high light. When the thylakoids are illuminated with extreme high light, the reaction center-binding D1 protein of PSII is photodamaged, and the damaged protein migrates to the grana margins for degradation and subsequent repair. In both moderate and extreme high-light conditions, fluidity of the thylakoid membrane is crucial. In this review, we first provide an overview of photoprotective processes, then discuss changes in membrane fluidity and mobility of the protein complexes in the grana under excessive light, which are closely associated with photoprotection of PSII. We hypothesize that reversible aggregation of LHCII, which is necessary to avoid light stress under moderate high light, and swift turnover of the photodamaged D1 protein under extreme high light are threatened by irreversible protein aggregation induced by reactive oxygen species in photochemical reactions.

  18. Quality Control of PSII: Behavior of PSII in the Highly Crowded Grana Thylakoids Under Excessive Light

    PubMed Central

    Yamamoto, Yasusi; Kai, Suguru; Ohnishi, Atsuki; Tsumura, Nodoka; Ishikawa, Tomomi; Hori, Haruka; Morita, Noriko; Ishikawa, Yasuo

    2014-01-01

    The grana thylakoids of higher plant chloroplasts are crowded with PSII and the associated light-harvesting complexes (LHCIIs). They constitute supercomplexes, and often form semi-crystalline arrays in the grana. The crowded condition of the grana may be necessary for efficient trapping of excitation energy by LHCII under weak light, but it might hinder proper movement of LHCII necessary for reversible aggregation of LHCII in the energy-dependent quenching of Chl fluorescence under moderate high light. When the thylakoids are illuminated with extreme high light, the reaction center-binding D1 protein of PSII is photodamaged, and the damaged protein migrates to the grana margins for degradation and subsequent repair. In both moderate and extreme high-light conditions, fluidity of the thylakoid membrane is crucial. In this review, we first provide an overview of photoprotective processes, then discuss changes in membrane fluidity and mobility of the protein complexes in the grana under excessive light, which are closely associated with photoprotection of PSII. We hypothesize that reversible aggregation of LHCII, which is necessary to avoid light stress under moderate high light, and swift turnover of the photodamaged D1 protein under extreme high light are threatened by irreversible protein aggregation induced by reactive oxygen species in photochemical reactions. PMID:24610582

  19. High-flux focusable color-tunable and efficient white-light-emitting diode light engine for stage lighting

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Maumita; Pedersen, Henrik Chresten; Petersen, Paul Michael; Poulsen, Christian; Poulsen, Peter Behrensdorff; Dam-Hansen, Carsten

    2016-08-01

    A color mixing light-emitting diode (LED) light engine that can replace 2-kW halogen-Fresnel spotlight with high-luminous flux in excess of 20,000 lm is reported for applications in professional stage and studio lighting. The light engine focuses and mixes the light from 210 LEDs of five different colors through a microlens array (MA) at the gate of Ø50 mm. Hence, it produces homogeneous color-mixed tunable white light from 3000 to 6000 K that can be adjustable from flood to spot position providing 10% translational loss, whereas the corresponding loss from the halogen-Fresnel spotlight is 37%. The design, simulation, and optimization of the light engine is described and compared to the experimental characterization of a prototype. The light engine is optimized through the simulated design of reflector, total internal reflection lens, and MA, as well as the number of LEDs. An optical efficiency of 59% and a luminous efficacy of 33 lm/W are achieved, which is three times higher than the 2-kW halogen-Fresnel spotlight. In addition to having color rendering of color rendering index Ra>85 and television lighting consistency index 12>70, the dimmable and tunable white light can be color controlled during the operational time.

  20. Diurnal variations of hormonal secretion, alertness and cognition in extreme chronotypes under different lighting conditions

    PubMed Central

    Maierova, L.; Borisuit, A.; Scartezzini, J.-L.; Jaeggi, S. M.; Schmidt, C.; Münch, M.

    2016-01-01

    Circadian rhythms in physiology and behavior are modulated by external factors such as light or temperature. We studied whether self-selected office lighting during the habitual waking period had a different impact on alertness, cognitive performance and hormonal secretion in extreme morning and evening chronotypes (N = 32), whose preferred bed- and wake-up times differed by several hours. The self-selected lighting condition was compared with constant bright light and a control condition in dim light. Saliva samples for hormonal analyses, subjective ratings of alertness, wellbeing, visual comfort and cognitive performance were regularly collected. Between the self-selected and the bright, but not the dim lighting condition, the onset of melatonin secretion in the evening (as marker for circadian phase) was significantly different for both chronotypes. Morning chronotypes reported a faster increase in sleepiness during the day than evening chronotypes, which was associated with higher cortisol secretion. Wellbeing, mood and performance in more difficult cognitive tasks were better in bright and self-selected lighting than in dim light for both chronotypes, whereas visual comfort was best in the self-selected lighting. To conclude, self-selection of lighting at work might positively influence biological and cognitive functions, and allow for inter-individual differences. PMID:27646174

  1. Quality indicators for high acuity pediatric conditions.

    PubMed

    Stang, Antonia S; Straus, Sharon E; Crotts, Jennifer; Johnson, David W; Guttmann, Astrid

    2013-10-01

    Identifying gaps in care and improving outcomes for severely ill children requires the development of evidence-based performance measures. We used a systematic process involving multiple stakeholders to identify and develop evidence-based quality indicators for high acuity pediatric conditions relevant to any emergency department (ED) setting where children are seen. A prioritized list of clinical conditions was selected by an advisory panel. A systematic review of the literature was conducted to identify existing indicators, as well as guidelines and evidence that could be used to inform the creation of new indicators. A multiphase, Rand-modified Delphi method consisting of anonymous questionnaires and a face-to-face meeting of an expert panel was used for indicator selection. Measure specifications and evidence grading were created for each indicator, and the feasibility and reliability of measurement was assessed in a tertiary care pediatric ED. The conditions selected for indicator development were diabetic ketoacidosis, status asthmaticus, anaphylaxis, status epilepticus, severe head injury, and sepsis. The majority of the 62 selected indicators reflect ED processes (84%) with few indicators reflecting structures (11%) or outcomes (5%). Thirty-seven percent (n = 23) of the selected indicators are based on moderate or high quality evidence. Data were available and interrater reliability acceptable for the majority of indicators. A systematic process involving multiple stakeholders was used to develop evidence-based quality indicators for high acuity pediatric conditions. Future work will test the reliability and feasibility of data collection on these indicators across the spectrum of ED settings that provide care for children.

  2. Light modulated toxicity of isoproturon toward natural stream periphyton photosynthesis: a comparison between constant and dynamic light conditions.

    PubMed

    Laviale, Martin; Prygiel, Jean; Créach, Anne

    2010-05-10

    This study tested if a variation in light intensity, in comparison to constant light required in well-designed toxicity test, could have measurable consequences on the sensitivity of phototrophic biofilms (periphyton) to isoproturon. Two independent experiments were carried out to investigate the combined effects of light and isoproturon on the photochemical behavior of intact natural biofilms by measurements of chlorophyll fluorescence and pigment composition. Experiment 1 consisted of exposing biofilms to series of isoproturon concentrations (0-2 mg L(-1)) for 7 h under constant light at different irradiance levels (25-300 micromol m(-2) s(-1)). In experiment 2, biofilms were exposed using more environmentally realistic conditions to three selected concentrations of isoproturon (2, 6 and 20 microg L(-1)) during a 7-h-simulated daily light cycle. Our results demonstrated that light, considered here as a direct physical stressor, slightly modulated the acute toxicity of isoproturon on these diatom dominated communities. This was attributed to the fact that these two factors act specifically on the photosynthetic activity. Furthermore, it was shown that a dynamic light regime increased periphyton sensitivity to isoproturon by challenging its photoprotective mechanisms such as the xanthophyll cycle, therefore implying that traditional ecotoxicological bioassays lead to underestimate the effect of isoproturon.

  3. Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle.

    PubMed

    Qin, Zong; Wang, Kai; Chen, Fei; Luo, Xiaobing; Liu, Sheng

    2010-08-02

    In this research, the condition for uniform lighting generated by array of LEDs with large view angle was studied. The luminous intensity distribution of LED is not monotone decreasing with view angle. A LED with freeform lens was designed as an example for analysis. In a system based on LEDs designed in house with a thickness of 20mm and rectangular arrangement, the condition for uniform lighting was derived and the analytical results demonstrated that the uniformity was not decreasing monotonously with the increasing of LED-to-LED spacing. The illuminance uniformities were calculated with Monte Carlo ray tracing simulations and the uniformity was found to increase with the increasing of certain LED-to-LED spacings anomalously. Another type of large view angle LED and different arrangements were discussed in addition. Both analysis and simulation results showed that the method is available for LED array lighting system design on the basis of large view angle LED..

  4. Bactericidal Mechanisms of Ag2O/TNBs under both Dark and Light Conditions

    NASA Astrophysics Data System (ADS)

    Jin, Yinjia; Dai, Zhaoyi; Liu, Fei; Kim, Hyunjung; Tong, Meiping; Hou, Yanglong

    2013-04-01

    Ag2O deposited titanium dioxides nanobelts (Ag2O/TNBs) were fabricated and used to investigate the toxic effects on aquatic microorganisms. The disinfection activities of Ag2O/TNBs on two representative bacterial strains: Gram-negative E. coli and Gram-positive B. subtilis, were examined under both dark and light conditions. Ag2O/TNBs exhibited stronger bactericidal activities than TNBs under both dark and light conditions. For both cell types, disinfection effects of Ag2O/TNBs were greater under light conditions relative to those under dark conditions. The bactericidal mechanisms of Ag2O/TNBs under both dark and light conditions were explored. Under dark conditions, neither Ag+ ions released from Ag2O/TNBs nor TNBs contributed to the bactericidal activities of Ag2O/TNBs. Under light conditions, both the released Ag+ions and TNBs yet were found to have contributions to the bactericidal effects of Ag2O/TNBs. Active species (H2O2, ?O2-, ande-) generated by Ag2O/TNBs played important roles in the disinfection processes under both dark and light conditions. Without the presence of active species, the direct contact of Ag2O/TNBs with bacterial cells had no bactericidal effect.

  5. Highly transparent light-harvesting window film.

    PubMed

    Cocilovo, Byron; Hashimura, Aki; Tweet, Douglas J; Voutsas, Tolis; Norwood, Robert A

    2015-10-20

    We have simulated unique textured window films that capture solar radiation without compromising the window's transparency by scattering infrared light toward photovoltaic strips located at the edges of the window. These films are ideal for powering electrochromic glass, which is difficult to install as each window requires its own power source. Our most promising design consists of an embedded array of 35° cones coated with a five-layer SiO2-Ag stack that was simulated to direct 1.4% of the incident light toward the edges and generate 1 W of power under a collimated 1000  W/m2 AM1.5G source at 60° and an average of 0.5 W over a full year when applied to a 1  m×1  m window. The internal visible transmittance of the window with the applied film is 95% at normal incidence, and remains above 85% for viewing angles up to 60°. The haze is 0.6% at normal incidence and 3.9% at 60°.

  6. Visible light metasurfaces based on gallium nitride high contrast gratings

    NASA Astrophysics Data System (ADS)

    Wang, Zhenhai; He, Shumin; Liu, Qifa; Wang, Wei

    2016-05-01

    We propose visible-light metasurfaces (VLMs) capable of serving as lens and beam deflecting element based on gallium nitride (GaN) high contrast gratings (HCGs). By precisely manipulating the wavefront of the transmitted light, we theoretically demonstrate an HCG focusing lens with transmissivity of 86.3%, and a VLM with beam deflection angle of 6.09° and transmissivity as high as 91.4%. The proposed all-dielectric metasurfaces are promising for GaN-based visible light-emitting diodes (LEDs), which would be robust and versatile for controlling the output light propagation and polarization, as well as enhancing the extraction efficiency of the LEDs.

  7. Age- and Wavelength-Dependency of Drosophila Larval Phototaxis and Behavioral Responses to Natural Lighting Conditions.

    PubMed

    Humberg, Tim-Henning; Sprecher, Simon G

    2017-01-01

    Animals use various environmental cues as key determinant for their behavioral decisions. Visual systems are hereby responsible to translate light-dependent stimuli into neuronal encoded information. Even though the larval eyes of the fruit fly Drosophila melanogaster are comparably simple, they comprise two types of photoreceptor neurons (PRs), defined by different Rhodopsin genes expressed. Recent findings support that for light avoidance Rhodopsin5 (Rh5) expressing photoreceptors are crucial, while Rhodopsin6 (Rh6) expressing photoreceptors are dispensable under laboratory conditions. However, it remains debated how animals change light preference during larval live. We show that larval negative phototaxis is age-independent as it persists in larvae from foraging to wandering developmental stages. Moreover, if spectrally different Rhodopsins are employed for the detection of different wavelength of light remains unexplored. We found that negative phototaxis can be elicit by light with wavelengths ranging from ultraviolet (UV) to green. This behavior is uniquely mediated by Rh5 expressing photoreceptors, and therefore suggest that this photoreceptor-type is able to perceive UV up to green light. In contrast to laboratory our field experiments revealed that Drosophila larvae uses both types of photoreceptors under natural lighting conditions. All our results, demonstrate that Drosophila larval eyes mediate avoidance of light stimuli with a wide, ecological relevant range of quantity (intensities) and quality (wavelengths). Thus, the two photoreceptor-types appear more likely to play a role in different aspects of phototaxis under natural lighting conditions, rather than color discrimination.

  8. Age- and Wavelength-Dependency of Drosophila Larval Phototaxis and Behavioral Responses to Natural Lighting Conditions

    PubMed Central

    Humberg, Tim-Henning; Sprecher, Simon G.

    2017-01-01

    Animals use various environmental cues as key determinant for their behavioral decisions. Visual systems are hereby responsible to translate light-dependent stimuli into neuronal encoded information. Even though the larval eyes of the fruit fly Drosophila melanogaster are comparably simple, they comprise two types of photoreceptor neurons (PRs), defined by different Rhodopsin genes expressed. Recent findings support that for light avoidance Rhodopsin5 (Rh5) expressing photoreceptors are crucial, while Rhodopsin6 (Rh6) expressing photoreceptors are dispensable under laboratory conditions. However, it remains debated how animals change light preference during larval live. We show that larval negative phototaxis is age-independent as it persists in larvae from foraging to wandering developmental stages. Moreover, if spectrally different Rhodopsins are employed for the detection of different wavelength of light remains unexplored. We found that negative phototaxis can be elicit by light with wavelengths ranging from ultraviolet (UV) to green. This behavior is uniquely mediated by Rh5 expressing photoreceptors, and therefore suggest that this photoreceptor-type is able to perceive UV up to green light. In contrast to laboratory our field experiments revealed that Drosophila larvae uses both types of photoreceptors under natural lighting conditions. All our results, demonstrate that Drosophila larval eyes mediate avoidance of light stimuli with a wide, ecological relevant range of quantity (intensities) and quality (wavelengths). Thus, the two photoreceptor-types appear more likely to play a role in different aspects of phototaxis under natural lighting conditions, rather than color discrimination. PMID:28473759

  9. Does anatoxin-a influence the physiology of Microcystis aeruginosa and Acutodesmus acuminatus under different light and nitrogen conditions?

    PubMed

    Chia, Mathias Ahii; Cordeiro-Araújo, Micheline Kézia; Lorenzi, Adriana Sturion; Bittencourt-Oliveira, Maria do Carmo

    2016-11-01

    Due to changing global climatic conditions, a lot of attention has been given to cyanobacteria and their bioactive secondary metabolites. These conditions are expected to increase the frequency of cyanobacterial blooms, and consequently, the concentrations of cyanotoxins in aquatic ecosystems. Unfortunately, there are very few studies that address the effects of cyanotoxins on the physiology of phytoplankton species under different environmental conditions. In the present study, we investigated the effect of the cyanotoxin anatoxin-a (ATX-A) on Microcystis aeruginosa (cyanobacteria) and Acutodesmus acuminatus (chlorophyta) under varying light and nitrogen conditions. Low light (LL) and nitrogen limitation (LN) resulted in significant cell density reduction of the two species, while the effect of ATX-A on M. aeruginosa was not significant. However, under normal (NN) and high nitrogen (HN) concentrations, exposure to ATX-A resulted in significantly (p < 0.05) lower cell density of A. acuminatus. Pigment content of M. aeruginosa significantly (p < 0.05) declined in the presence of ATX-A, regardless of the light condition. Under each light condition, exposure to ATX-A caused a reduction in total microcystin (MC) content of M. aeruginosa. The detected MC levels varied as a function of nitrogen and ATX-A concentrations. The production of reactive oxygen species (H2O2) and antioxidant enzyme activities of both species were significantly altered by ATX-A under different light and nitrogen conditions. Our results revealed that under different light and nitrogen conditions, the response of M. aeruginosa and A. acuminatus to ATX-A was variable, which demonstrated the need for different endpoints of environmental factors during ecotoxicological investigations.

  10. Stray-light suppression with high-collection efficiency in laser light-scattering experiments

    NASA Technical Reports Server (NTRS)

    Deilamian, K.; Gillaspy, J. D.; Kelleher, D. E.

    1992-01-01

    An optical system is described for collecting a large fraction of fluorescent light emitted isotropically from a cylindrical interaction region. While maintaining an overall detection efficiency of 9 percent, the system rejects, by more than 12 orders of magnitude, incident laser light along a single axis that intersects the interaction region. Such a system is useful for a wide variety of light-scattering experiments in which high-collection efficiency is desirable, but in which light from an incident laser beam must be rejected without resorting to spectral filters.

  11. White-light LED clusters with high color rendering.

    PubMed

    He, Guoxing; Zheng, Lihong

    2010-09-01

    We established a model for spectra of LEDs at different drive currents. The simulation program of color rendering of white-light LED clusters has been developed, according to the principle of additive color mixture. The experimental results show that white/red LED clusters can realize color temperature untunable white light with a high color rendering index and high luminous efficacy and that neutral-white/red/blue LED clusters can realize color temperature tunable white light with a high color rendering index and high luminous efficacy.

  12. Analysis of light emitting diode array lighting system based on human vision: normal and abnormal uniformity condition.

    PubMed

    Qin, Zong; Ji, Chuangang; Wang, Kai; Liu, Sheng

    2012-10-08

    In this paper, condition for uniform lighting generated by light emitting diode (LED) array was systematically studied. To take human vision effect into consideration, contrast sensitivity function (CSF) was novelly adopted as critical criterion for uniform lighting instead of conventionally used Sparrow's Criterion (SC). Through CSF method, design parameters including system thickness, LED pitch, LED's spatial radiation distribution and viewing condition can be analytically combined. In a specific LED array lighting system (LALS) with foursquare LED arrangement, different types of LEDs (Lambertian and Batwing type) and given viewing condition, optimum system thicknesses and LED pitches were calculated and compared with those got through SC method. Results show that CSF method can achieve more appropriate optimum parameters than SC method. Additionally, an abnormal phenomenon that uniformity varies with structural parameters non-monotonically in LALS with non-Lambertian LEDs was found and analyzed. Based on the analysis, a design method of LALS that can bring about better practicability, lower cost and more attractive appearance was summarized.

  13. Structure light telecentric stereoscopic vision 3D measurement system based on Scheimpflug condition

    NASA Astrophysics Data System (ADS)

    Mei, Qing; Gao, Jian; Lin, Hui; Chen, Yun; Yunbo, He; Wang, Wei; Zhang, Guanjin; Chen, Xin

    2016-11-01

    We designed a new three-dimensional (3D) measurement system for micro components: a structure light telecentric stereoscopic vision 3D measurement system based on the Scheimpflug condition. This system creatively combines the telecentric imaging model and the Scheimpflug condition on the basis of structure light stereoscopic vision, having benefits of a wide measurement range, high accuracy, fast speed, and low price. The system measurement range is 20 mm×13 mm×6 mm, the lateral resolution is 20 μm, and the practical vertical resolution reaches 2.6 μm, which is close to the theoretical value of 2 μm and well satisfies the 3D measurement needs of micro components such as semiconductor devices, photoelectron elements, and micro-electromechanical systems. In this paper, we first introduce the principle and structure of the system and then present the system calibration and 3D reconstruction. We then present an experiment that was performed for the 3D reconstruction of the surface topography of a wafer, followed by a discussion. Finally, the conclusions are presented.

  14. Proteins involved in biophoton emission and flooding-stress responses in soybean under light and dark conditions.

    PubMed

    Kamal, Abu Hena Mostafa; Komatsu, Setsuko

    2016-02-01

    To know the molecular systems basically flooding conditions in soybean, biophoton emission measurements and proteomic analyses were carried out for flooding-stressed roots under light and dark conditions. Photon emission was analyzed using a photon counter. Gel-free quantitative proteomics were performed to identify significant changes proteins using the nano LC-MS along with SIEVE software. Biophoton emissions were significantly increased in both light and dark conditions after flooding stress, but gradually decreased with continued flooding exposure compared to the control plants. Among the 120 significantly identified proteins in the roots of soybean plants, 73 and 19 proteins were decreased and increased in the light condition, respectively, and 4 and 24 proteins were increased and decreased, respectively, in the dark condition. The proteins were mainly functionally grouped into cell organization, protein degradation/synthesis, and glycolysis. The highly abundant lactate/malate dehydrogenase proteins were decreased in flooding-stressed roots exposed to light, whereas the lysine ketoglutarate reductase/saccharopine dehydrogenase bifunctional enzyme was increased in both light and dark conditions. Notably, however, specific enzyme assays revealed that the activities of these enzymes and biophoton emission were sharply increased after 3 days of flooding stress. This finding suggests that the source of biophoton emission in roots might involve the chemical excitation of electron or proton through enzymatic or non-enzymatic oxidation and reduction reactions. Moreover, the lysine ketoglutarate reductase/saccharopine dehydrogenase bifunctional enzyme may play important roles in responses in flooding stress of soybean under the light condition and as a contributing factor to biophoton emission.

  15. Resin-based composite light-cured properties assessed by laboratory standards and simulated clinical conditions.

    PubMed

    Ilie, N; Bauer, H; Draenert, M; Hickel, R

    2013-01-01

    SUMMARY The following parameters were varied: 1) irradiation technique: top and bottom polymerization according to the ISO standard, and polymerization from only the top, simulating clinical situations; 2) polymerization time: 5, 10, 20, and 40 seconds; 3) storage conditions: 24 hours in distilled water, thermocycling followed by storage for four weeks in artificial saliva or alcohol. Flexural strength (FS), flexural modulus (Eflexural), indentation modulus (E), Vickers hardness (HV), and degree of conversion (DC) were measured. The laboratory results were similar to those measured by mimicking clinical conditions only at high polymerization times and mild storage conditions (20 seconds and 40 seconds and storage for 24 hours in water, and 40 seconds with aging and storing in saliva). Significantly higher DC values were measured on the top than on the bottom of a 2-mm layer for all polymerization times. Overall, 5-second and 10-second irradiation times induced significantly lower DC values compared to the currently recommended polymerization times of 20 and 40 seconds at both the top and bottom of the samples. The initial DC differences as a function of irradiation time are leveled at 24 hours of storage but seem to do well in predicting long-term material behavior. A minimum irradiation time of 20 seconds is necessary clinically to achieve the best mechanical properties with modern high-intensity light emitting diode (LED) units.

  16. Symbiodinium transcriptome and global responses of cells to immediate changes in light intensity when grown under autotrophic or mixotrophic conditions.

    PubMed

    Xiang, Tingting; Nelson, William; Rodriguez, Jesse; Tolleter, Dimitri; Grossman, Arthur R

    2015-04-01

    Symbiosis between unicellular dinoflagellates (genus Symbiodinium) and their cnidarian hosts (e.g. corals, sea anemones) is the foundation of coral reef ecosystems. Dysfunction of this symbiosis under changing environmental conditions has led to global reef decline. Little information is known about Symbiodinium gene expression and mechanisms by which light impacts host-symbiont associations. To address these issues, we generated a transcriptome from axenic Symbiodinium strain SSB01. Here we report features of the transcriptome, including occurrence and length distribution of spliced leader sequences, the functional landscape of encoded proteins and the impact of light on gene expression. Expression of many Symbiodinium genes appears to be significantly impacted by light. Transcript encoding cryptochrome 2 declined in high light while some transcripts for Regulators of Chromatin Condensation (RCC1) declined in the dark. We also identified a transcript encoding a light harvesting AcpPC protein with homology to Chlamydomonas LHCSR2. The level of this transcript increased in high light autotrophic conditions, suggesting that it is involved in photo-protection and the dissipation of excess absorbed light energy. The most extensive changes in transcript abundances occurred when the algae were transferred from low light to darkness. Interestingly, transcripts encoding several cell adhesion proteins rapidly declined following movement of cultures to the dark, which correlated with a dramatic change in cell surface morphology, likely reflecting the complexity of the extracellular matrix. Thus, light-sensitive cell adhesion proteins may play a role in establishing surface architecture, which may in turn alter interactions between the endosymbiont and its host.

  17. Thiol-Capped Gold Nanoparticles Swell-Encapsulated into Polyurethane as Powerful Antibacterial Surfaces Under Dark and Light Conditions

    PubMed Central

    Macdonald, Thomas J.; Wu, Ke; Sehmi, Sandeep K.; Noimark, Sacha; Peveler, William J.; du Toit, Hendrik; Voelcker, Nicolas H.; Allan, Elaine; MacRobert, Alexander J.; Gavriilidis, Asterios; Parkin, Ivan P.

    2016-01-01

    A simple procedure to develop antibacterial surfaces using thiol-capped gold nanoparticles (AuNPs) is shown, which effectively kill bacteria under dark and light conditions. The effect of AuNP size and concentration on photo-activated antibacterial surfaces is reported and we show significant size effects, as well as bactericidal activity with crystal violet (CV) coated polyurethane. These materials have been proven to be powerful antibacterial surfaces against both Gram-positive and Gram-negative bacteria. AuNPs of 2, 3 or 5 nm diameter were swell-encapsulated into PU before a coating of CV was applied (known as PU-AuNPs-CV). The antibacterial activity of PU-AuNPs-CV samples was tested against Staphylococcus aureus and Escherichia coli as representative Gram-positive and Gram-negative bacteria under dark and light conditions. All light conditions in this study simulated a typical white-light hospital environment. This work demonstrates that the antibacterial activity of PU-AuNPs-CV samples and the synergistic enhancement of photoactivity of triarylmethane type dyes is highly dependent on nanoparticle size and concentration. The most powerful PU-AuNPs-CV antibacterial surfaces were achieved using 1.0 mg mL−1 swell encapsulation concentrations of 2 nm AuNPs. After two hours, Gram-positive and Gram-negative bacteria were reduced to below the detection limit (>4 log) under dark and light conditions. PMID:27982122

  18. Thiol-Capped Gold Nanoparticles Swell-Encapsulated into Polyurethane as Powerful Antibacterial Surfaces Under Dark and Light Conditions

    NASA Astrophysics Data System (ADS)

    MacDonald, Thomas J.; Wu, Ke; Sehmi, Sandeep K.; Noimark, Sacha; Peveler, William J.; Du Toit, Hendrik; Voelcker, Nicolas H.; Allan, Elaine; MacRobert, Alexander J.; Gavriilidis, Asterios; Parkin, Ivan P.

    2016-12-01

    A simple procedure to develop antibacterial surfaces using thiol-capped gold nanoparticles (AuNPs) is shown, which effectively kill bacteria under dark and light conditions. The effect of AuNP size and concentration on photo-activated antibacterial surfaces is reported and we show significant size effects, as well as bactericidal activity with crystal violet (CV) coated polyurethane. These materials have been proven to be powerful antibacterial surfaces against both Gram-positive and Gram-negative bacteria. AuNPs of 2, 3 or 5 nm diameter were swell-encapsulated into PU before a coating of CV was applied (known as PU-AuNPs-CV). The antibacterial activity of PU-AuNPs-CV samples was tested against Staphylococcus aureus and Escherichia coli as representative Gram-positive and Gram-negative bacteria under dark and light conditions. All light conditions in this study simulated a typical white-light hospital environment. This work demonstrates that the antibacterial activity of PU-AuNPs-CV samples and the synergistic enhancement of photoactivity of triarylmethane type dyes is highly dependent on nanoparticle size and concentration. The most powerful PU-AuNPs-CV antibacterial surfaces were achieved using 1.0 mg mL‑1 swell encapsulation concentrations of 2 nm AuNPs. After two hours, Gram-positive and Gram-negative bacteria were reduced to below the detection limit (>4 log) under dark and light conditions.

  19. Metabolomic analysis indicates a pivotal role of the hepatotoxin microcystin in high light adaptation of Microcystis.

    PubMed

    Meissner, Sven; Steinhauser, Dirk; Dittmann, Elke

    2015-05-01

    Microcystis is a freshwater cyanobacterium frequently forming nuisance blooms in the summer months. The genus belongs to the predominant producers of the potent hepatotoxin microcystin. The success of Microcystis and its remarkable resistance to high light conditions are not well understood. Here, we have compared the metabolic response of Microcystis aeruginosa PCC7806, its microcystin-deficient ΔmcyB mutant (Mut) and the cyanobacterial model organism Synechocystis PCC6803 to high light exposure of 250 μmol photons m(-2)  s(-1) using GC/MS-based metabolomics. Microcystis wild type and Mut show pronounced differences in their metabolic reprogramming upon high light. Seventeen per cent of the detected metabolites showed significant differences between the two genotypes after high light exposure. Whereas the microcystin-producing wild type shows a faster accumulation of glycolate upon high light illumination, loss of microcystin leads to an accumulation of general stress markers such as trehalose and sucrose. The study further uncovers differences in the high light adaptation of the bloom-forming cyanobacterium Microcystis and the model cyanobacterium Synechocystis. Most notably, Microcystis invests more into carbon reserves such as glycogen after high light exposure. Our data shed new light on the lifestyle of bloom-forming cyanobacteria, the role of the widespread toxin microcystin and the metabolic diversity of cyanobacteria.

  20. Observations of swash under highly dissipative conditions

    NASA Astrophysics Data System (ADS)

    Ruessink, B. G.; Kleinhans, M. G.; van den Beukel, P. G. L.

    1998-02-01

    Video measurements of swash were made at the low-sloping beach of the multiple bar system at Terschelling, Netherlands. The majority of the measurements were conducted under highly dissipative conditions with Iribarren numbers ξ0 (the ratio of beach slope to the square root of offshore wave steepness) less than 0.2. Infragravity (0.004-0.05 Hz) waves dominated the swash with an average ratio of infragravity and total swash height Rig/R of 0.85. Using linear regression we investigated the dependence of swash parameters on environmental conditions such as short-wave height, period, and local beach slope. On average, Rig was about 30% of the offshore wave height H0; the slope in the linear H0 dependence of Rig amounted to only 0.18, considerably smaller than that observed on steeper beaches. The data set shows evidence for saturation of the higher infragravity frequencies for ξ0 less than, roughly, 0.27. In our opinion, this saturation caused the constant of proportionality in the linear relationship between Rig/H0 and ξ0 to be significantly larger than that observed under higher Iribarren number regimes. The saturated tails of the swash spectra had an approximate f-3 roll-off (where f is frequency), whereas, in general, the nonsaturated parts were white. This lack of significant peaks casts doubt on the causality between infragravity waves and nearshore bars.

  1. πSPIM: high NA high resolution isotropic light-sheet imaging in cell culture dishes

    PubMed Central

    Theer, Patrick; Dragneva, Denitsa; Knop, Michael

    2016-01-01

    Light-sheet fluorescence microscopy (LSFM), also termed single plane illumination microscopy (SPIM), enables live cell fluorescence imaging with optical sectioning capabilities superior to confocal microscopy and without any out-of-focus exposure of the specimen. However, the need of two objective lenses, one for light-sheet illumination and one for imaging, imposes geometrical constraints that require LSFM setups to be adapted to the specific needs of different types of specimen in order to obtain optimal imaging conditions. Here we demonstrate the use of an oblique light-sheet configuration adapted to provide the highest possible Gaussian beam enabled resolution in LSFM. The oblique light-sheet configuration furthermore enables LSFM imaging at the surface of a cover slip, without the need of specific sample mounting. In addition, the system is compatible with simultaneous high NA wide-field epi-fluorescence imaging of the specimen contained in a glass-bottom cell culture dish. This prevents cumbersome sample mounting and enables rapid screening of large areas of the specimen followed by high-resolution LSFM imaging of selected cells. We demonstrate the application of this microscope for in toto imaging of endocytosis in yeast, showing for the first time imaging of all endocytic events of a given cell over a period of >5 minutes with sub-second resolution. PMID:27619647

  2. High-performance LED street lighting using microlens arrays.

    PubMed

    Lee, Xuan-Hao; Moreno, Ivan; Sun, Ching-Cherng

    2013-05-06

    An efficient LED lamp that illuminates the street with high quality is presented. The luminaire shows high optical efficiency, high optical utilization factor, low glare, and illuminates the street with high uniformity. The concept is simple but effective: a cluster of LEDs with TIR lenses are put inside a reflective box, which is covered with a microlens sheet; the reflective cavity improves efficiency by light recycling; each TIR lens collimates the LED light for the microlens array; and the microlens sheet uniformly distributes light only into the street. We verify its feasibility by Monte Carlo ray-tracing for the main types of road lighting arrangements: central, zigzag, and single-side pole positions.

  3. Effectiveness of dye sensitised solar cell under low light condition using wide band dye

    SciTech Connect

    Sahmer, Ahmad Zahrin Mohamed, Norani Muti Zaine, Siti Nur Azella

    2015-07-22

    Dye sensistised solar cell (DSC) based on nanocrystalline TiO{sub 2} has the potential to be used in indoor consumer power application. In realizing this, the DSC must be optimized to generate power under low lighting condition and under wider visible light range. The use of wide band dye N749 which has a wider spectrum sensitivity increases the photon conversion to electron between the visible light spectrums of 390nm to 700nm. This paper reports the study on the effectiveness of the dye solar cell with N749 dye under low light condition in generating usable power which can be used for indoor consumer application. The DSC was fabricated using fluorine doped tin oxide (FTO) glass with screen printing method and the deposited TiO{sub 2} film was sintered at 500°C. The TiO{sub 2} coated FTO glass was then soaked in the N749 dye, assembled into test cell, and tested under the standard test condition at irradiance of 1000 W/m{sup 2} with AM1.5 solar soaker. The use of the 43T mesh for the dual pass screen printing TiO{sub 2} paste gives a uniform TiO{sub 2} film layer of 16 µm. The low light condition was simulated using 1/3 filtered irradiance with the solar soaker. The fabricated DSC test cell with the N749 dye was found to have a higher efficiency of 6.491% under low light condition compared to the N719 dye. Under the standard test condition at 1 sun the N749 test cell efficiency is 4.55%. The increases in efficiency is attributed to the wider spectral capture of photon of the DSC with N749 dye. Furthermore, the use of N749 dye is more effective under low light condition as the V{sub OC} decrement is less significant compared to the latter.

  4. MORPHOLOGICAL AND PHYSIOLOGICAL EFFECTS IN PROBOSCIA ALATA (BACILLARIOPHYCEAE) GROWN UNDER DIFFERENT LIGHT AND CO2 CONDITIONS OF THE MODERN SOUTHERN OCEAN(1).

    PubMed

    Hoogstraten, Astrid; Timmermans, Klaas R; de Baar, Hein J W

    2012-06-01

    The combined effects of different light and aqueous CO2 conditions were assessed for the Southern Ocean diatom Proboscia alata (Brightwell) Sundström in laboratory experiments. Selected culture conditions (light and CO2(aq) ) were representative for the natural ranges in the modern Southern Ocean. Light conditions were 40 (low) and 240 (high) μmol photons · m(-2)  · s(-1) . The three CO2(aq) conditions ranged from 8 to 34 μmol · kg(-1) CO2(aq) (equivalent to a pCO2 from 137 to 598 μatm, respectively). Clear morphological changes were induced by these different CO2(aq) conditions. Cells in low [CO2(aq) ] formed spirals, while many cells in high [CO2(aq) ] disintegrated. Cell size and volume were significantly affected by the different CO2(aq) concentrations. Increasing CO2(aq) concentrations led to an increase in particulate organic carbon concentrations per cell in the high light cultures, with exactly the opposite happening in the low light cultures. However, other parameters measured were not influenced by the range of CO2(aq) treatments. This included growth rates, chlorophyll a concentration and photosynthetic yield (FV /FM ). Different light treatments had a large effect on nutrient uptake. High light conditions caused an increased nutrient uptake rate compared to cells grown in low light conditions. Light and CO2 conditions co-determined in various ways the response of P. alata to changing environmental conditions. Overall P. alata appeared to be well adapted to the natural variability in light availability and CO2(aq) concentration of the modern Southern Ocean. Nevertheless, our results showed that P. alata is susceptible to future changes in inorganic carbon concentrations in the Southern Ocean.

  5. High illuminance light-emitting diode headlight for medical applications

    NASA Astrophysics Data System (ADS)

    Lee, Ui-Hyung; Jung, Jae-hun; Park, Seung Hyun; Lee, Gye Seon; Ju, Young-Gu

    2010-11-01

    High brightness light emitting diodes have been used to develop high illuminance headlight for medical applications. It provides various advantages such as high illuminance, long life time, reduced infra red light, extended operation time with battery and light weight. A 3 W LED was employed to achieve the high performance medical headlight. The optical design includes two lenses for high energy transmission and high illuminance. The LED headlight shows 42,000 lux with spot diameter of 80 mm at the distance of 300 mm. For comparison purpose, 5 W LED was also used to obtain the high illuminance headlight. However, the large divergence angle and large spot size of the 5 W LED limits the illuminance to 31,000 lux with increased burden on heat dissipation. The thermal images of the heat sinks indicate that the temperature of the headlight using a 3 W LED is below 50 degree C, which is suitable for medical applications.

  6. Directional orientation of birds by the magnetic field under different light conditions.

    PubMed

    Wiltschko, Roswitha; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2010-04-06

    This paper reviews the directional orientation of birds with the help of the geomagnetic field under various light conditions. Two fundamentally different types of response can be distinguished. (i) Compass orientation controlled by the inclination compass that allows birds to locate courses of different origin. This is restricted to a narrow functional window around the total intensity of the local geomagnetic field and requires light from the short-wavelength part of the spectrum. The compass is based on radical-pair processes in the right eye; magnetite-based receptors in the beak are not involved. Compass orientation is observed under 'white' and low-level monochromatic light from ultraviolet (UV) to about 565 nm green light. (ii) 'Fixed direction' responses occur under artificial light conditions such as more intense monochromatic light, when 590 nm yellow light is added to short-wavelength light, and in total darkness. The manifestation of these responses depends on the ambient light regime and is 'fixed' in the sense of not showing the normal change between spring and autumn; their biological significance is unclear. In contrast to compass orientation, fixed-direction responses are polar magnetic responses and occur within a wide range of magnetic intensities. They are disrupted by local anaesthesia of the upper beak, which indicates that the respective magnetic information is mediated by iron-based receptors located there. The influence of light conditions on the two types of response suggests complex interactions between magnetoreceptors in the right eye, those in the upper beak and the visual system.

  7. Directional orientation of birds by the magnetic field under different light conditions

    PubMed Central

    Wiltschko, Roswitha; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2010-01-01

    This paper reviews the directional orientation of birds with the help of the geomagnetic field under various light conditions. Two fundamentally different types of response can be distinguished. (i) Compass orientation controlled by the inclination compass that allows birds to locate courses of different origin. This is restricted to a narrow functional window around the total intensity of the local geomagnetic field and requires light from the short-wavelength part of the spectrum. The compass is based on radical-pair processes in the right eye; magnetite-based receptors in the beak are not involved. Compass orientation is observed under ‘white’ and low-level monochromatic light from ultraviolet (UV) to about 565 nm green light. (ii) ‘Fixed direction’ responses occur under artificial light conditions such as more intense monochromatic light, when 590 nm yellow light is added to short-wavelength light, and in total darkness. The manifestation of these responses depends on the ambient light regime and is ‘fixed’ in the sense of not showing the normal change between spring and autumn; their biological significance is unclear. In contrast to compass orientation, fixed-direction responses are polar magnetic responses and occur within a wide range of magnetic intensities. They are disrupted by local anaesthesia of the upper beak, which indicates that the respective magnetic information is mediated by iron-based receptors located there. The influence of light conditions on the two types of response suggests complex interactions between magnetoreceptors in the right eye, those in the upper beak and the visual system. PMID:19864263

  8. Intraocular pressure fluctuations of growing chick eyes are suppressed in constant light conditions.

    PubMed

    Wahl, Christina; Li, Tong; Howland, Howard C

    2016-07-01

    We report measurements of intraocular pressure (IOP) in growing domestic chicks at 12 h intervals, with three different lighting conditions. One group of chicks was raised in 12 h light and 12 h darkness (N), another in constant light (CL), and the third group was initially exposed to CL for three weeks then returned to N for either one week or four weeks (CLN). Pressures were measured in the middle of the light and dark periods (noon and midnight) for N and CLN birds, and at corresponding 12 h intervals for CL birds (also noon and midnight). The IOP of N chicks fluctuated from a light period average value of 25 mm Hg ( ±1.3 SD), to a dark period average value of 17.5 mm Hg ( ±1.1 SD mm Hg; P < 0.0001). These pressures were established by 4 days of age. At 7 weeks, (N) IOP continued to fluctuate: light values were 21.7 mm Hg (±1.2 SD), and dark values were 18.3 mm Hg ( ±0.7 SD). The IOP of CL birds did not fluctuate, remaining steady at 17 mm Hg ( ±1.4 SD). Chicks exposed to CL for 3 weeks required more than one week in N to re-establish (N) IOP values. We conclude that IOP fluctuates in hatchling chicks under N light conditions, that fluctuation is suppressed in CL light conditions, and that IOP recovery from 3 weeks suppression in CL requires more than one week in N light conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Accumulation of phenylpropanoids and correlated gene expression in hairy roots of tartary buckwheat under light and dark conditions.

    PubMed

    Thwe, Aye Aye; Kim, YeJi; Li, Xiaohua; Kim, Yeon Bok; Park, Nam-Il; Kim, Haeng Hoon; Kim, Sun-Ju; Park, Sang Un

    2014-12-01

    Differential expression patterns of flavonoid biosynthetic pathway genes in the hairy roots of tartary buckwheat cultivars "Hokkai T8" and "Hokkai T10" were studied over a time course of the light-dark cycle. The Agrobacterium rhizogenes-mediated transformation system was applied for inducing hairy roots. Further, a total of six phenolic compounds and two anthocyanins were analyzed in the hairy roots which were exposed to both light and dark conditions, and their amounts were estimated by HPLC. The gene expression levels peaked on day 5 of culture during the time course of both dark and light conditions. Notably, FtPAL, Ft4CL, FtC4H, FtCHI, FtF3H, FtF3'H-1, and FtFLS-1 were more highly expressed in Hokkai T10 than in Hokkai T8 under dark conditions, among which FtPAL and FtCHI were found to be significantly upregulated, except on day 20 of culture. Significantly higher levels of phenolic compound, rutin, along with two anthocyanins were detected in the hairy roots of Hokkai T10 under both conditions. Furthermore, among all the phenolic compounds detected, the amount of rutin in Hokkai T10 hairy roots was found to be ∼5-fold (59,01 mg/g dry weight) higher than that in the control (12.45 mg/g dry weight) at the respective time periods under light and dark conditions.

  10. High efficiency III-nitride light-emitting diodes

    DOEpatents

    Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

    2013-05-28

    Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

  11. Comparative efficiency of plasma and halogen light sources on composite micro-hardness in different curing conditions.

    PubMed

    Dietschi, D; Marret, N; Krejci, I

    2003-09-01

    Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions. Vicker's micro-hardness values were performed on 1 and 2 mm thick composite discs cured in a natural tooth mold by direct irradiation or indirect irradiation through composite material (2 or 4 mm) and dental tissues (1 mm enamel or 2 mm enamel-dentin). Measures were, respectively, performed after a 1, 3, 6 s (SC, step curing mode) or 18 s (3xSC) exposure to the plasma light, and a 5, 10, 20 or 40 s exposure to the halogen light. With the PAC light used, a 3 s irradiation in the direct curing condition was necessary to reach hardness values similar to those obtained after a 40 s exposure to the halogen light. Using the indirect curing condition, hardness values reached after an 18 s exposure (3xSC mode) with the plasma light were either equivalent or inferior to those obtained with 40 s halogen irradiation. Direct polymerization with the plasma light used requires longer exposure times than those initially proposed by the manufacturer. The effectiveness of plasma generated light was lowered by composite or natural tissues, and therefore requires an important increase in the irradiation time when applied to indirect polymerization. The practical advantage of this polymerization method is less than expected, when compared to traditional halogen curing.

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

    In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed. PMID:26327154

  14. Characterization of lighted upflow anaerobic sludge blanket (LUASB) method under sulfate-rich conditions.

    PubMed

    Sawayama, S; Tsukahara, K; Yagishita, T; Hanada, S

    2001-01-01

    Growth of phototrophic bacteria was induced from granules in a lighted upflow anaerobic sludge blanket (LUASB) reactor supplied with an organic-acid-based medium containing 141.7 mg S.l(-1) of SO4(2-) under light conditions (100 microE.m(-2).s(-1)). We investigated the population dynamics of phototrophic bacteria in the LUASB reactor and the performance of the LUASB reactor for wastewater treatment and poly-beta-hydroxybutyrate (PHB) production under anaerobic light and sulfate-rich conditions. In vivo absorption spectra and a colony count suggested that populations of Rhodopseudomonas palustris and Blastochloris sulfoviridis in the LUASB reactor supplied with a medium containing 574.4 mg S.l(-1) of SO4(2-) under light conditions were lower than those supplied with a medium containing 1.0 or 141.7 mg S.l(-1) of SO4(2-) under parallel conditions. Removal efficiencies of ammonium and phosphate in the LUASB reactor supplied with the medium containing 141.7 mg S.l(-1) of SO4(2-) under light conditions were higher than those under parallel conditions but without illumination. The difference in the results of runs under light or dark conditions suggested that the ammonium and phosphate ion removal efficiencies were improved by increasing the amount of phototrophic bacterial biomass in the LUASB reactor under sulfate-rich conditions. The average PHB production rates of the bacterial cells recovered from the effluent of the LUASB reactor supplied with a medium containing 141.7, 283.5 or 574.4 mg S.l(-1) of SO4(2-) were 1.0-2.9 mg.l(-1)-reactor.d(-1) and the average PHB content based on the dry bacterial biomass was 1.4-3.6%.

  15. High-output LED-based light engine for profile lighting fixtures with high color uniformity using freeform reflectors.

    PubMed

    Gadegaard, Jesper; Jensen, Thøger Kari; Jørgensen, Dennis Thykjær; Kristensen, Peter Kjær; Søndergaard, Thomas; Pedersen, Thomas Garm; Pedersen, Kjeld

    2016-02-20

    In the stage lighting and entertainment market, light engines (LEs) for lighting fixtures are often based on high-intensity discharge (HID) bulbs. Switching to LED-based light engines gives possibilities for fast switching, additive color mixing, a longer lifetime, and potentially, more energy-efficient systems. The lumen output of a single LED is still not sufficient to replace an HID source in high-output profile fixtures, but combining multiple LEDs can create an LE with a similar output, but with added complexity. This paper presents the results of modeling and testing such a light engine. Custom ray-tracing software was used to design a high-output red, green and blue LED-based light engine with twelve CBT-90 LEDs using a dual-reflector principle. The simulated optical system efficiency was 0.626 with a perfect (R=1) reflector coating for light delivered on a target surface through the entire optical system. A profile lighting fixture prototype was created, and provided an output of 6744 lumen and an efficiency of 0.412. The lower efficiency was mainly due to a non-optimal reflector coating, and the optimized design is expected to reach a significantly higher efficiency.

  16. Biological dinitrogen fixation by selected soil cyanobacteria as affected by strain origin, morphotype, and light conditions.

    PubMed

    Hrčková, K; Simek, M; Hrouzek, P; Lukešová, A

    2010-09-01

    The potential for N(2) fixation by heterocystous cyanobacteria isolated from soils of different geographical areas was determined as nitrogenase activity (NA) using the acetylene reduction assay. Morphology of cyanobacteria had the largest influence on NA determined under light conditions. NA was generally higher in species lacking thick slime sheaths. The highest value (1446 nmol/h C(2)H(4) per g fresh biomass) was found in the strain of branched cyanobacterium Hassalia (A Has1) from the polar region. A quadratic relationship between NA and biomass was detected in the Tolypothrix group under light conditions. The decline of NA in dark relative to light conditions ranged from 37 to 100 % and differed among strains from distinct geographical areas. Unlike the NA of temperate and tropical strains, whose decline in dark relative to light was 24 and 17 %, respectively, the NA of polar strains declined to 1 % in the dark. This difference was explained by adaptation to different light conditions in temperate, tropical, and polar habitats. NA was not related to the frequency of heterocysts in strains of the colony-forming cyanobacterium Nostoc. Colony morphology and life cycle are therefore more important for NA then heterocyst frequency. NA values probably reflect the environmental conditions where the cyanobacterium was isolated and the physiological and morphological state of the strain.

  17. Face relighting from a single image under arbitrary unknown lighting conditions.

    PubMed

    Wang, Yang; Zhang, Lei; Liu, Zicheng; Hua, Gang; Wen, Zhen; Zhang, Zhengyou; Samaras, Dimitris

    2009-11-01

    In this paper, we present a new method to modify the appearance of a face image by manipulating the illumination condition, when the face geometry and albedo information is unknown. This problem is particularly difficult when there is only a single image of the subject available. Recent research demonstrates that the set of images of a convex Lambertian object obtained under a wide variety of lighting conditions can be approximated accurately by a low-dimensional linear subspace using a spherical harmonic representation. Moreover, morphable models are statistical ensembles of facial properties such as shape and texture. In this paper, we integrate spherical harmonics into the morphable model framework by proposing a 3D spherical harmonic basis morphable model (SHBMM). The proposed method can represent a face under arbitrary unknown lighting and pose simply by three low-dimensional vectors, i.e., shape parameters, spherical harmonic basis parameters, and illumination coefficients, which are called the SHBMM parameters. However, when the image was taken under an extreme lighting condition, the approximation error can be large, thus making it difficult to recover albedo information. In order to address this problem, we propose a subregion-based framework that uses a Markov random field to model the statistical distribution and spatial coherence of face texture, which makes our approach not only robust to extreme lighting conditions, but also insensitive to partial occlusions. The performance of our framework is demonstrated through various experimental results, including the improved rates for face recognition under extreme lighting conditions.

  18. High root temperature affects the tolerance to high light intensity in Spathiphyllum plants.

    PubMed

    Soto, Adriana; Hernández, Laura; Quiles, María José

    2014-10-01

    Spathiphyllum wallisii plants were sensitive to temperature stress under high illumination, although the susceptibility of leaves to stress may be modified by root temperature. Leaves showed higher tolerance to high illumination, in both cold and heat conditions, when the roots were cooled, probably because the chloroplast were protected by excess excitation energy dissipation mechanisms such as cyclic electron transport. When the roots were cooled both the activity of electron donation by NADPH and ferredoxin to plastoquinone and the amount of PGR5 polypeptide, an essential component of cyclic electron flow around PSI, increased. However, when the stems were heated or cooled under high illumination, but the roots were heated, the quantum yield of PSII decreased considerably and neither the electron donation activity by NADPH and ferredoxin to plastoquinone nor the amount of PGR5 polypeptide increased. In such conditions, the cyclic electron flow cannot be enhanced by high light and PSII is damaged as a result of insufficient dissipation of excess light energy. Additionally, the damage to PSII induced the increase in both chlororespiratory enzymes, NDH complex and PTOX. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Depth of cure of sealants polymerized with high-power light emitting diode curing lights.

    PubMed

    Kitchens, Brandon; Wells, Martha; Tantbirojn, Daranee; Versluis, Antheunis

    2015-03-01

    To determine whether recommended short curing times of three high-power light emitting diode (LED) curing lights are sufficient to polymerize sealant materials. Opaque-unfilled sealant (Delton LC Opaque), opaque-filled sealant (UltraSeal XT plus), and clear-filled sealant (FluroShield) were light cured in a covered slot-mold using the manufacturers' shortest recommended curing times with three high-power LED lights (3-s VALO, 5-s Fusion, 10-s Smartlite). A 40-s cure with a quartz-tungsten halogen (QTH) light was used as control. Vickers hardness was measured 24 h after curing at the sealant surface and through the depth (0.5 mm increments) (N = 10). Results were analyzed with two-way anova (pair-wise multiple comparisons, significance level 0.05). The high-power LEDs did not cure the sealants as deep as the QTH. Delton LC Opaque showed the least depth of cure as hardness values beyond a depth of 0.5 mm were not measurable regardless of the curing light. Even for UltraSeal XT plus, when surface hardness was about the same with all lights, hardness decreased more rapidly with depth for the LEDs. FluroShield showed the slowest decline in hardness through the depth for all lights. Manufacturers' recommendations for shortest possible curing time with high-power LEDs were not sufficient for adequate polymerization of the tested sealants. © 2014 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Effect of BPA on the germination, root development, seedling growth and leaf differentiation under different light conditions in Arabidopsis thaliana.

    PubMed

    Pan, Wen-Juan; Xiong, Can; Wua, Qiu-Ping; Liu, Jin-Xia; Liao, Hong-Mei; Chen, Wei; Liu, Yong-Sheng; Zheng, Lei

    2013-11-01

    Bisphenol A (BPA) is a well-known environmental toxic substance, which exerts unfavorable effects through endocrine disruptor (ER)-dependent and ER-independent mechanisms to threaten ecological systems seriously. BPA may also interact with other environmental factors, such as light and heavy metals, to have a synergetic effect in plants. However, there is little data concerning the toxic effect of BPA on the primary producers-plants and its possible interaction with light-dependent response. Here, the effects of BPA on germination, fresh weight, tap root length, and leaf differentiation were studied in Arabidopsis thaliana under different parts of light spectrum (dark, red, yellow, green, blue, and white light). Our results showed that low-dose BPA (1.0, 5.0 µM) caused an increase in the fresh weight, the tap root length and the lateral root formation of A. thaliana seedlings, while high-dose BPA (10.0, 25.0 µM) show an inhibition effect in a dose-dependent manner. Unlike karrikins, the effects of BPA on germination fresh weight and tap roots length under various light conditions are similar, which imply that BPA has no notable role in priming light response in germination and early seedling growth in A. thaliana. Meanwhile, BPA exposure influences the differentiation of A. thaliana leaf blade significantly in a light-dependent manner with little to no effect in dark and clear effect under red illumination.

  1. High-intensity environmental light in dementia: effect on sleep and activity.

    PubMed

    Sloane, Philip D; Williams, Christianna S; Mitchell, C Madeline; Preisser, John S; Wood, Wendy; Barrick, Ann Louise; Hickman, Susan E; Gill, Karminder S; Connell, Bettye Rose; Edinger, Jack; Zimmerman, Sheryl

    2007-10-01

    To determine whether high-intensity ambient light in public areas of long-term care facilities will improve sleeping patterns and circadian rhythms of persons with dementia. A cluster-unit crossover intervention trial involving four conditions: morning bright light, evening bright light, all-day bright light, and minimum standard light. The common areas of two geriatric units in a psychiatric hospital and a dementia-specific residential care facility. Sixty-six older adults with dementia. Ambient bright light of approximately 2,500 lux, delivered through a low-glare lighting system installed in the dining and activity areas. Participant exposure averaged 2.5 to 3.0 hours for the morning and evening interventions and 8.4 hours for the all-day intervention. Nighttime sleep using wrist actigraphy and daytime activity using nonobtrusive daytime observations. Night-time sleep increased significantly in participants exposed to morning and all-day light, with the increase most prominent in participants with severe or very severe dementia (mean increase 16 minutes (P=.008) for morning, and 14 minutes (P=.01) for all-day). Morning light produced a mean phase advance of 29 minutes (P=.02) and evening light a mean phase delay of 15 minutes (P=.06). Effects on daytime sleepiness were inconsistent, and the number of sleep bouts, mesor, amplitude, intradaily variability, and interdaily stability were not significantly different, indicating that the overall strength of day and night activity rhythms did not change significantly under any treatment condition. Bright light appears to have a modest but measurable effect on sleep in this population, and ambient light may be preferable to stationary devices such as light boxes.

  2. A guideline for analyzing circadian wheel-running behavior in rodents under different lighting conditions

    PubMed Central

    Jud, Corinne; Schmutz, Isabelle; Hampp, Gabriele; Oster, Henrik

    2005-01-01

    Most behavioral experiments within circadian research are based on the analysis of locomotor activity. This paper introduces scientists to chronobiology by explaining the basic terminology used within the field. Furthermore, it aims to assist in designing, carrying out, and evaluating wheel-running experiments with rodents, particularly mice. Since light is an easily applicable stimulus that provokes strong effects on clock phase, the paper focuses on the application of different lighting conditions. PMID:16136228

  3. Nanosecond high-power dense microplasma switch for visible light

    SciTech Connect

    Bataller, A. Koulakis, J.; Pree, S.; Putterman, S.

    2014-12-01

    Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

  4. New lighting for the design of high quality biomedical devices

    NASA Astrophysics Data System (ADS)

    Jaffe, Claudia B.; Jaffe, Steven M.; Conner, Arlie R.

    2009-02-01

    Among the trends redefining 21st century biomedical diagnostics and therapeutics are the advent of low-cost portable analyzers. Because light is a powerful tool in many of today's most widely used life science instruments, high intensity, low cost light engines are essential to the design and proliferation of the newest bioanalytical instruments, medical devices and miniaturized analyzers. The development of new light technology represents a critical technical hurdle in the realization of point-of-care analysis. Lumencor has developed an inexpensive lighting solution, uniquely well suited to the production of safe, effective and commercially viable life science tools and biomedical devices. Lumencor's proprietary, solid-state light engine provides powerful, pure, stable, inexpensive light across the UV-Vis- NIR. Light engines are designed to directly replace the entire configuration of light management components with a single, simple unit. Power, spectral breadth and purity, stability and reliability data will demonstrate the advantages of these light engines for today's bioanalytical needs. Performance and cost analyses will be compared to traditional optical subsystems based on lamps, lasers and LEDs with respect to their suitability as sources for biomedical applications, implementation for development/evaluation of novel measurement tools and overall superior reliability. Next generation products based on such sources will be described to fulfill the demand for portable, hand-held analyzers and affordable devices with highly integrated light sources. A four color violet/cyan/green/red product will be demonstrated. A variety of multicolor prototypes, their spectral outputs and facile modulation will be discussed and their performance capabilities disclosed.

  5. Photomorphogenesis and pigment induction in lentil seedling roots exposed to low light conditions.

    PubMed

    Vollsnes, A V; Melø, T B; Futsaether, C M

    2012-05-01

    Although roots are normally hidden in soil, they may inadvertently be exposed to low light levels in experiments or in natural conditions through cracks or light transmittance through the soil. Light has been implicated in root morphogenesis. Thus, effects of low light conditions on lentil (Lens culinaris L. cv. Verte du Puy) root morphology and root pigmentation were studied. Lentil seedlings were grown in peat or transparent, nutrient-fortified agar at a 12-h light (PAR 240 μmol · m(-2) · s(-1)), 12-h dark cycle. Roots were exposed to low levels (≈ 1-10 μmol · m(-2) · s(-1)) of broadband white light, either directly or indirectly by aboveground light penetrating the growth medium. Control roots were grown in darkness. In situ spectroscopy was used to measure transmittance and reflectance spectra of intact root tissue by mounting the upper part of the primary root directly in a spectrophotometer equipped with an integrating sphere attachment. The transmittance and reflectance spectra were used to calculate the in situ root absorbance spectrum. Absorbance bands were found in the regions 480-500 nm and 650-680 nm, possibly due to low levels of root-localised carotenoids and chlorophylls, respectively. Low light levels (≈ 1-10 μmol · m(-2) · s(-1) ) transmitted through the growth medium significantly increased root pigment concentration and root biomass, and altered root morphology by enhancing lateral root formation and inhibiting root elongation relative to roots grown in complete darkness. The light-induced changes in root morphogenesis and pigmentation appear to be primarily due to upper root light perception. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  6. Light emission of metal halide lamps under micro- and hypergravity conditions

    SciTech Connect

    Stoffels, W.W.; Kemps, P.C.M.; Beckers, J.; Kroesen, G.M.W.; Haverlag, M.

    2005-12-12

    The wavelength-integrated light output from a metal halide discharge lamp is measured for gravity conditions varying from 0 to 1.8 g during parabolic flights. The results show that the changing gravity affects the convection flow in the lamp, which in turn changes the total light output. For vertically burning lamps, the sign and magnitude of the effect can be predicted using the demixing parameter: the ratio of typical diffusion to convection times. In horizontally burning lamps at 0 g, the absence of convective mixing results in a reduced light emission.

  7. Adaptations in rod outer segment disc membranes in response to environmental lighting conditions.

    PubMed

    Rakshit, Tatini; Senapati, Subhadip; Parmar, Vipul M; Sahu, Bhubanananda; Maeda, Akiko; Park, Paul S-H

    2017-10-01

    The light-sensing rod photoreceptor cell exhibits several adaptations in response to the lighting environment. While adaptations to short-term changes in lighting conditions have been examined in depth, adaptations to long-term changes in lighting conditions are less understood. Atomic force microscopy was used to characterize the structure of rod outer segment disc membranes, the site of photon absorption by the pigment rhodopsin, to better understand how photoreceptor cells respond to long-term lighting changes. Structural properties of the disc membrane changed in response to housing mice in constant dark or light conditions and these adaptive changes required output from the phototransduction cascade initiated by rhodopsin. Among these were changes in the packing density of rhodopsin in the membrane, which was independent of rhodopsin synthesis and specifically affected scotopic visual function as assessed by electroretinography. Studies here support the concept of photostasis, which maintains optimal photoreceptor cell function with implications in retinal degenerations. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Effects of blue light deficiency on acclimation of light energy partitioning in PSII and CO2 assimilation capacity to high irradiance in spinach leaves.

    PubMed

    Matsuda, Ryo; Ohashi-Kaneko, Keiko; Fujiwara, Kazuhiro; Kurata, Kenji

    2008-04-01

    Blue light effects on the acclimation of energy partitioning characteristics in PSII and CO2 assimilation capacity in spinach to high growth irradiance were investigated. Plants were grown hydroponically in different light treatments that were a combination of two light qualities and two irradiances,i.e. white light and blue-deficient light at photosynthetic photon flux densities (PPFDs) of 100 and 500 micromol m(-2) s(-1). The CO2 assimilation rate, the quantum efficiency of PSII(PhiPSII) and thermal dissipation activity (F(v)/F(m)-F'(v)/F'(m)) in young, fully expanded leaves were measured under 1,600 micromol m(-2) s(-1) white light. The CO2 assimilation rate and (PhiPSII) were higher, while F(v)/F(m)-F'(v)/F'(m) was lower in plants grown under high irradiance than in plants grown under low irradiance. These responses were observed irrespective of the presence or absence of blue light during growth. The extent of the increase in the CO2 assimilation rate and PhiPSII and the decrease in F(v)/F(m)-F'(v)/F'(m) by high growth irradiance was smaller under blue light-deficient conditions. These results indicate that blue light helps to boost the acclimation responses of energy partitioning in PSII and CO2 assimilation to high irradiance. Similarly, leaf N, Cyt f and Chl contents per unit leaf area increased by high growth irradiance, and the extent of the increment in leaf N, Cyt f and Chl was smaller under blue light-deficient conditions. Regression analysis showed that the differences in energy partitioning in PSIIand CO2 assimilation between plants grown under high white light and high blue-deficient light were closely related to the difference in leaf N.

  9. LED light engine concept with ultra-high scalable luminance

    NASA Astrophysics Data System (ADS)

    Hoelen, Christoph; de Boer, Dick; Bruls, Dominique; van der Eyden, Joost; Koole, Rolf; Li, Yun; Mirsadeghi, Mo; Vanbroekhoven, Vincent; Van den Bergh, John-John; Van de Voorde, Patrick

    2016-03-01

    Although LEDs have been introduced successfully in many general lighting applications during the past decade, high brightness light source applications are still suffering from the limited luminance of LEDs. High power LEDs are generally limited in luminance to ca 100 Mnit (108 lm/m2sr) or less, while dedicated devices for projection may achieve luminance values up to ca 300 Mnit with phosphor converted green. In particular for high luminous flux applications with limited étendue, like in front projection systems, only very modest luminous flux values in the beam can be achieved with LEDs compared to systems based on discharge lamps. In this paper we introduce a light engine concept based on a light converter rod pumped with blue LEDs that breaks through the étendue and brightness limits of LEDs, enabling LED light source luminance values that are more than 4 times higher than what can be achieved with LEDs so far. In LED front projection systems, green LEDs are the main limiting factor. With our green light emitting modules, peak luminance values well above 1.2 Gnit have been achieved, enabling doubling of the screen brightness of LED based DLP projection systems, and even more when this technology is applied to other colors as well. This light source concept, introduced as the ColorSpark High Lumen Density (HLD) LED technology, enables a breakthrough in the performance of LED-based light engines not only for projection, where >2700 ANSI lm was demonstrated, but for a wide variety of high brightness applications.

  10. Matter under extreme conditions experiments at the Linac Coherent Light Source

    DOE PAGES

    Glenzer, S. H.; Fletcher, L. B.; Galtier, E.; ...

    2015-12-10

    The Matter in Extreme Conditions end station at the Linac Coherent Light Source (LCLS) is a new tool enabling accurate pump-probe measurements for studying the physical properties of matter in the high-energy density physics regime. This instrument combines the world’s brightest x-ray source, the LCLS x-ray beam, with high-power lasers consisting of two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These lasers produce short-lived states of matter with high pressures, high temperatures or high densities with properties that are important for applications in nuclear fusion research, laboratory astrophysics and the development of intense radiation sources. In the firstmore » experiments, we have performed highly accurate x-ray diffraction and x-ray Thomson scattering techniques on shock-compressed matter resolving the transition from compressed solid matter to a co-existence regime and into the warm dense matter state. Furthermore, these complex charged-particle systems are dominated by strong correlations and quantum effects. They exist in planetary interiors and laboratory experiments, e.g., during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions. Applying record peak brightness X rays resolves the ionic interactions at atomic (Ångstrom) scale lengths and measure the static structure factor, which is a key quantity for determining equation of state data and important transport coefficients. Simultaneously, spectrally resolved measurements of plasmon features provide dynamic structure factor information that yield temperature and density with unprecedented precision at micron-scale resolution in dynamic compression experiments. This set of studies demonstrates our ability to measure fundamental thermodynamic properties that determine the state of matter in the high-energy density physics regime.« less

  11. Highly efficient light management for perovskite solar cells.

    PubMed

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-06

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  12. Highly efficient light management for perovskite solar cells

    PubMed Central

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells. PMID:26733112

  13. Increased collection efficiency of LIFI high intensity electrodeless light source

    NASA Astrophysics Data System (ADS)

    Hafidi, Abdeslam; DeVincentis, Marc; Duelli, Markus; Gilliard, Richard

    2008-02-01

    Recently, RF driven electrodeless high intensity light sources have been implemented successfully in the projection display systems for HDTV and videowall applications. This paper presents advances made in the RF waveguide and electric field concentrator structures with the purpose of reducing effective arc size and increasing light collection. In addition, new optical designs are described that further improve system efficiency. The results of this work demonstrate that projection system light throughput is increased relative to previous implementations and performance is optimized for home theater and other front projector applications that maintain multi-year lifetime without re-lamping, complete spectral range, fast start times and high levels of dynamic contrast due to dimming flexibility in the light source system.

  14. Highly efficient light management for perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  15. High-resolution light microscopy for interpretation of renal biopsies.

    PubMed

    Hoffmann, E O

    1995-12-01

    Routine transmission electron microscopy is recommended for all renal biopsies. However, most of the diagnostic lesions in renal pathology are 0.2 micron or larger, and are therefore visible by light microscopy. These lesions are difficult to evaluate in paraffin sections due to problems inherent in the method itself. Full utilization of the resolving power of the light microscope or high-resolution light microscopy is possible with resin (plastic) histotechnology. The replacement of conventional histotechnology by epoxy histotechnology allows the visualization of most subcellular structures needed for accurate diagnosis in renal pathology. Electron microscopy remains a very helpful tool for selected morphological problems.

  16. Lead paint removal with high-intensity light pulses.

    PubMed

    Grapperhaus, Michael J; Schaefer, Raymond B

    2006-12-15

    This paper presents the results of an initial investigation into using high-intensity incoherent light pulses to strip paint. Measurements of light pulse characteristics, the reflectivity of different paints and initial experiments on the threshold for paint removal, and paint removal are presented, along with an approximate model consistent with experimental results. Paint removal tests include lead paint, the reduction of lead levels to below levels required for lead abatement, as well as air and light emissions measurements that are within regulatory guidelines.

  17. Microbial Thiocyanate Utilization under Highly Alkaline Conditions

    PubMed Central

    Sorokin, Dimitry Y.; Tourova, Tatyana P.; Lysenko, Anatoly M.; Kuenen, J. Gijs

    2001-01-01

    Three kinds of alkaliphilic bacteria able to utilize thiocyanate (CNS−) at pH 10 were found in highly alkaline soda lake sediments and soda soils. The first group included obligate heterotrophs that utilized thiocyanate as a nitrogen source while growing at pH 10 with acetate as carbon and energy sources. Most of the heterotrophic strains were able to oxidize sulfide and thiosulfate to tetrathionate. The second group included obligately autotrophic sulfur-oxidizing alkaliphiles which utilized thiocyanate nitrogen during growth with thiosulfate as the energy source. Genetic analysis demonstrated that both the heterotrophic and autotrophic alkaliphiles that utilized thiocyanate as a nitrogen source were related to the previously described sulfur-oxidizing alkaliphiles belonging to the gamma subdivision of the division Proteobacteria (the Halomonas group for the heterotrophs and the genus Thioalkalivibrio for autotrophs). The third group included obligately autotrophic sulfur-oxidizing alkaliphilic bacteria able to utilize thiocyanate as a sole source of energy. These bacteria could be enriched on mineral medium with thiocyanate at pH 10. Growth with thiocyanate was usually much slower than growth with thiosulfate, although the biomass yield on thiocyanate was higher. Of the four strains isolated, the three vibrio-shaped strains were genetically closely related to the previously described sulfur-oxidizing alkaliphiles belonging to the genus Thioalkalivibrio. The rod-shaped isolate differed from the other isolates by its ability to accumulate large amounts of elemental sulfur inside its cells and by its ability to oxidize carbon disulfide. Despite its low DNA homology with and substantial phenotypic differences from the vibrio-shaped strains, this isolate also belonged to the genus Thioalkalivibrio according to a phylogenetic analysis. The heterotrophic and autotrophic alkaliphiles that grew with thiocyanate as an N source possessed a relatively high level of cyanase

  18. Photorespiration participates in the assimilation of acetate in Chlorella sorokiniana under high light.

    PubMed

    Xie, Xiujun; Huang, Aiyou; Gu, Wenhui; Zang, Zhengrong; Pan, Guanghua; Gao, Shan; He, Linwen; Zhang, Baoyu; Niu, Jianfeng; Lin, Apeng; Wang, Guangce

    2016-02-01

    The development of microalgae on an industrial scale largely depends on the economic feasibility of mass production. High light induces productive suspensions during cultivation in a tubular photobioreactor. Herein, we report that high light, which inhibited the growth of Chlorella sorokiniana under autotrophic conditions, enhanced the growth of this alga in the presence of acetate. We compared pigments, proteomics and the metabolic flux ratio in C. sorokiniana cultivated under high light (HL) and under low light (LL) in the presence of acetate. Our results showed that high light induced the synthesis of xanthophyll and suppressed the synthesis of chlorophylls. Acetate in the medium was exhausted much more rapidly in HL than in LL. The data obtained from LC-MS/MS indicated that high light enhanced photorespiration, the Calvin cycle and the glyoxylate cycle of mixotrophic C. sorokiniana. The results of metabolic flux ratio analysis showed that the majority of the assimilated carbon derived from supplemented acetate, and photorespiratory glyoxylate could enter the glyoxylate cycle. Based on these data, we conclude that photorespiration provides glyoxylate to speed up the glyoxylate cycle, and releases acetate-derived CO2 for the Calvin cycle. Thus, photorespiration connects the glyoxylate cycle and the Calvin cycle, and participates in the assimilation of supplemented acetate in C. sorokiniana under high light. © 2015 Institute of Oceanography, Chinese Academy of Sciences (IOCAS). New Phytologist © 2015 New Phytologist Trust.

  19. Photo acoustic study of plants exposed to varying light intensity growth conditions: Spectral and morphological changes

    NASA Astrophysics Data System (ADS)

    Mesquita, R. C.; Barja, P. R.; da Silva, E. C.; Mansanares, A. M.

    2005-06-01

    In this paper we describe results of photo acoustic (PA) measurements carried out on various plants exposed to varying light intensity conditions. Depending on the species and light intensity conditions, the PA absorption spectra show differences in peaks associated with pigments and the cuticle. These differences are related to the spatial distribution of the pigments that differs from plant to plant. We have also performed systematic study of oxygen evolution at different wavelengths. The obtained oxygen spectra are equivalent to the action spectra usually acquired by determining the CO2 uptake and energy storage. The intensities of oxygen spectra exhibit differences depending on distinct morphology of plant.

  20. H2 production in Rhodopseudomonas palustris as a way to cope with high light intensities.

    PubMed

    Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

    2016-06-01

    The ability of coping with the damaging effects of high light intensity represents an essential issue when purple non-sulfur bacteria (PNSB) are grown under direct sunlight for photobiological hydrogen production. This study was aimed at investigating whether H2 photo-evolution could represent, for Rhodopseudomonas palustris 42OL, a safety valve to dissipate an excess of reducing power generated under high light intensities. The physiological status of this strain was assessed under anaerobic (AnG) and aerobic (AG) growing conditions and under H2-producing (HP) conditions at low and high light intensities. The results obtained clearly showed that Fv/Fm ratio was significantly affected by the light intensity under which R. palustris 42OL cells were grown, under either AnG or AG conditions, while, under HP, it constantly remained at its highest value. The increase in light intensity significantly increased the H2 production rate, which showed a positive correlation with the maximum electron transfer rate (rETRmax). These findings are important for optimization of hydrogen production by PNSB under solar light.

  1. Matter under extreme conditions experiments at the Linac Coherent Light Source

    NASA Astrophysics Data System (ADS)

    Glenzer, S. H.; Fletcher, L. B.; Galtier, E.; Nagler, B.; Alonso-Mori, R.; Barbrel, B.; Brown, S. B.; Chapman, D. A.; Chen, Z.; Curry, C. B.; Fiuza, F.; Gamboa, E.; Gauthier, M.; Gericke, D. O.; Gleason, A.; Goede, S.; Granados, E.; Heimann, P.; Kim, J.; Kraus, D.; MacDonald, M. J.; Mackinnon, A. J.; Mishra, R.; Ravasio, A.; Roedel, C.; Sperling, P.; Schumaker, W.; Tsui, Y. Y.; Vorberger, J.; Zastrau, U.; Fry, A.; White, W. E.; Hasting, J. B.; Lee, H. J.

    2016-05-01

    The matter in extreme conditions end station at the Linac Coherent Light Source (LCLS) is a new tool enabling accurate pump-probe measurements for studying the physical properties of matter in the high-energy density (HED) physics regime. This instrument combines the world’s brightest x-ray source, the LCLS x-ray beam, with high-power lasers consisting of two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These lasers produce short-lived states of matter with high pressures, high temperatures or high densities with properties that are important for applications in nuclear fusion research, laboratory astrophysics and the development of intense radiation sources. In the first experiments, we have performed highly accurate x-ray diffraction and x-ray Thomson scattering measurements on shock-compressed matter resolving the transition from compressed solid matter to a co-existence regime and into the warm dense matter state. These complex charged-particle systems are dominated by strong correlations and quantum effects. They exist in planetary interiors and laboratory experiments, e.g., during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions. Applying record peak brightness x-rays resolves the ionic interactions at atomic (Ångstrom) scale lengths and measure the static structure factor, which is a key quantity for determining equation of state data and important transport coefficients. Simultaneously, spectrally resolved measurements of plasmon features provide dynamic structure factor information that yield temperature and density with unprecedented precision at micron-scale resolution in dynamic compression experiments. These studies have demonstrated our ability to measure fundamental thermodynamic properties that determine the state of matter in the HED physics regime.

  2. Light management for photovoltaics using high-index nanostructures

    NASA Astrophysics Data System (ADS)

    Brongersma, Mark L.; Cui, Yi; Fan, Shanhui

    2014-05-01

    High-performance photovoltaic cells use semiconductors to convert sunlight into clean electrical power, and transparent dielectrics or conductive oxides as antireflection coatings. A common feature of these materials is their high refractive index. Whereas high-index materials in a planar form tend to produce a strong, undesired reflection of sunlight, high-index nanostructures afford new ways to manipulate light at a subwavelength scale. For example, nanoscale wires, particles and voids support strong optical resonances that can enhance and effectively control light absorption and scattering processes. As such, they provide ideal building blocks for novel, broadband antireflection coatings, light-trapping layers and super-absorbing films. This Review discusses some of the recent developments in the design and implementation of such photonic elements in thin-film photovoltaic cells.

  3. Physiological functions of PsbS-dependent and PsbS-independent NPQ under naturally fluctuating light conditions.

    PubMed

    Ikeuchi, Masahiro; Uebayashi, Nozomu; Sato, Fumihiko; Endo, Tsuyoshi

    2014-07-01

    The PsbS protein plays an important role in dissipating excess light energy as heat in photosystem II (PSII). However, the physiological importance of PsbS under naturally fluctuating light has not been quantitatively estimated. Here we investigated energy allocation in PSII in PsbS-suppressed rice transformants (ΔpsbS) under both naturally fluctuating and constant light conditions. Under constant light, PsbS was essential for inducing the rapid formation of light-inducible thermal dissipation (Φ(NPQ)), which consequently suppressed the rapid formation of basal intrinsic decay (Φ(f,D)), while the quantum yield of electron transport (Φ(II)) did not change. In the steady state phase, the difference between the wild type (WT) and ΔpsbS was minimized. Under regularly fluctuating light, the reduced PsbS resulted in higher Φ(II) upon the transition from high light to low light and in lower Φ(II) upon the transition from low light to high light, indicating that Φ(II) was, to some extent, controlled by PsbS. Under naturally fluctuating light in a greenhouse, rapid changes in Φ(II) were compensated by Φ(NPQ) in the WT, but by Φ(f,D) in ΔpsbS. As a consequence, a significantly lower ΣNPQ integrated Φ(NPQ) over a whole day) and higher Σf,D were found in ΔpsbS. Furthermore, thermal dissipation associated with photoinhibtion was enhanced in ΔpsbS. These results suggest that PsbS plays an important role in photoprotective process at the induction phase of photosynthesis as well as under field conditions. The physiological relevance of PsbS as a photoprotection mechanism and the identities of Φ(NPQ) and Φ(f,D) are discussed. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. Nonlinear light scattering by high-index dielectric nanoparticles

    NASA Astrophysics Data System (ADS)

    Smirnova, Daria A.

    2017-09-01

    Recently emerged new platform for nanophotonics based on high-index dielectric nanoparticles utilizes optically-induced magnetic response via multipolar resonances, and provides many novel opportunities for subwavelength nonlinear optics. Here, we summarize our studies on nonlinear light scattering by high-permittivity dielectric nanoparticles and oligomers, and demonstrate approaches for achieving highly-efficient frequency conversion and directional harmonic radiation at the nanoscale. We analyze the multipolar nature of the generated electromagnetic fields by combining analytical and numerical methods. Our results delineate a roadmap towards design of miniature light sources and nonlinear photonic metadevices with exceptional characteristics.

  5. High Resolution Measurement of Light in Terrestrial Ecosystems Using Photodegrading Dyes

    PubMed Central

    Roales, Javier; Durán, Jorge; Bechtold, Heather A.; Groffman, Peter M.; Rosi-Marshall, Emma J.

    2013-01-01

    Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT) and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem. PMID:24069440

  6. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    PubMed

    Roales, Javier; Durán, Jorge; Bechtold, Heather A; Groffman, Peter M; Rosi-Marshall, Emma J

    2013-01-01

    Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT) and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  7. Effects of light shading and climatic conditions on the metabolic behavior of flonicamid in red bell pepper.

    PubMed

    Jung, Da-I; Farha, Waziha; Abd El-Aty, A M; Kim, Sung-Woo; Rahman, Md Musfiqur; Choi, Jeong-Heui; Kabir, Md Humayun; Im, So Jeong; Lee, Young-Jun; Truong, Lieu T B; Shin, Ho-Chul; Im, Geon-Jae; Shim, Jae-Han

    2016-03-01

    The degradation behavior of flonicamid and its metabolites (4-trifluoromethylnicotinic acid (TFNA) and N-(4-trifluoromethylnicotinoyl) glycine (TFNG)) was evaluated in red bell pepper over a period of 90 days under glass house conditions, including high temperature, low and high humidity, and in a vinyl house covered with high density polyethylene light shade covering film (35 and 75%). Flonicamid (10% active ingredient) was applied (via foliar application) to all fruits, including those groups grown under normal conditions (glass house) or under no shade cover (vinyl house). Samples were extracted using a Quick, Easy, Cheap, Effective, Rugged, and Safe "QuEChERS" method and analyzed using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The method performance, including linearity, recovery, limits of detection (LOD), and quantitation (LOQ), was satisfactory. Throughout the experimental period, the residual levels of flonicamid and TFNG were not uniform, whereas that of TFNA remained constant. The total sum of the residues (flonicamid and its metabolites) was higher in the vinyl house with shade cover than in the glass house, under various conditions. The total residues were significantly higher when the treatment was applied under high light shade (75%). The flonicamid half-life decreased from 47.2 days (under normal conditions) to 28.4 days (at high temperatures) in the glass house, while it increased from 47.9 days (no shade cover) to 66 days (75% light shading) in the vinyl house. High humidity leads to decreases in the total sum of flonicamid residues in red bell pepper grown in a glass house, because it leads to an increase in the rate of water loss, which in turn accelerates the volatilization of the pesticide. For safety reasons, it is advisable to grow red bell pepper under glass house conditions because of the effects of solar radiation, which increases the rate of flonicamid degradation into its metabolites.

  8. Angle of sky light polarization derived from digital images of the sky under various conditions.

    PubMed

    Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Yang, Yi; Ning, Yu

    2017-01-20

    Skylight polarization is used for navigation by some birds and insects. Skylight polarization also has potential for human navigation applications. Its advantages include relative immunity from interference and the absence of error accumulation over time. However, there are presently few examples of practical applications for polarization navigation technology. The main reason is its weak robustness during cloudy weather conditions. In this paper, the real-time measurement of the sky light polarization pattern across the sky has been achieved with a wide field of view camera. The images were processed under a new reference coordinate system to clearly display the symmetrical distribution of angle of polarization with respect to the solar meridian. A new algorithm for the extraction of the image axis of symmetry is proposed, in which the real-time azimuth angle between the camera and the solar meridian is accurately calculated. Our experimental results under different weather conditions show that polarization navigation has high accuracy, is strongly robust, and performs well during fog and haze, clouds, and strong sunlight.

  9. High light intensity protects photosynthetic apparatus of pea plants against exposure to lead.

    PubMed

    Romanowska, E; Wróblewska, B; Drozak, A; Siedlecka, M

    2006-01-01

    The electron transport rates and coupling factor activity in the chloroplasts; adenylate contents, rates of photosynthesis and respiration in the leaves as well as activity of isolated mitochondria were investigated in Pisum sativum L. leaves of plants grown under low or high light intensity and exposed after detachment to 5 mM Pb(NO(3))(2). The presence of Pb(2+) reduced rate of photosynthesis in the leaves from plants grown under the high light (HL) and low light (LL) conditions, whereas the respiration was enhanced in the leaves from HL plants. Mitochondria from Pb(2+) treated HL-leaves oxidized glycine at a higher rate than those isolated from LL leaves. ATP content in the Pb-treated leaves increased to a greater extend in the HL than LL grown plants. Similarly ATP synthase activity increased markedly when chloroplasts isolated from control and Pb-treated leaves of HL and LL grown plants were subjected to high intensity light. The presence of Pb ions was found inhibit ATP synthase activity only in chloroplasts from LL grown plants or those illuminated with low intensity light. Low light intensity during growth also lowered PSI electron transport rates and the Pb(2+) induced changes in photochemical activity of this photosystem were visible only in the chloroplasts isolated from LL grown plants. The activity of PSII was influenced by Pb ions on similar manner in both light conditions. This study demonstrates that leaves from plants grown under HL conditions were more resistant to lead toxicity than those obtained from the LL grown plants. The data indicate that light conditions during growth might play a role in regulation of photosynthetic and respiratory energy conservation in heavy metal stressed plants by increasing the flexibility of the stoichiometry of ATP to ADP production.

  10. Scalable Light Module for Low-Cost, High-Efficiency Light- Emitting Diode Luminaires

    SciTech Connect

    Tarsa, Eric

    2015-08-31

    During this two-year program Cree developed a scalable, modular optical architecture for low-cost, high-efficacy light emitting diode (LED) luminaires. Stated simply, the goal of this architecture was to efficiently and cost-effectively convey light from LEDs (point sources) to broad luminaire surfaces (area sources). By simultaneously developing warm-white LED components and low-cost, scalable optical elements, a high system optical efficiency resulted. To meet program goals, Cree evaluated novel approaches to improve LED component efficacy at high color quality while not sacrificing LED optical efficiency relative to conventional packages. Meanwhile, efficiently coupling light from LEDs into modular optical elements, followed by optimally distributing and extracting this light, were challenges that were addressed via novel optical design coupled with frequent experimental evaluations. Minimizing luminaire bill of materials and assembly costs were two guiding principles for all design work, in the effort to achieve luminaires with significantly lower normalized cost ($/klm) than existing LED fixtures. Chief project accomplishments included the achievement of >150 lm/W warm-white LEDs having primary optics compatible with low-cost modular optical elements. In addition, a prototype Light Module optical efficiency of over 90% was measured, demonstrating the potential of this scalable architecture for ultra-high-efficacy LED luminaires. Since the project ended, Cree has continued to evaluate optical element fabrication and assembly methods in an effort to rapidly transfer this scalable, cost-effective technology to Cree production development groups. The Light Module concept is likely to make a strong contribution to the development of new cost-effective, high-efficacy luminaries, thereby accelerating widespread adoption of energy-saving SSL in the U.S.

  11. Spatial light modulators for high-brightness projection displays.

    PubMed

    Takizawa, K; Fujii, T; Kikuchi, H; Fujikake, H; Kawakita, M; Hirano, Y; Sato, F

    1999-09-10

    We fabricated polymer-dispersed liquid-crystal light valves (PDLCLV's) consisting of a 30-microm-thick hydrogenated amorphous-silicon film and a 10-microm-thick polymer-dispersed liquid-crystal (PDLC) film composed of nematic liquid-crystal (LC) microdroplets surrounded by polymer. The device can modulate high-power reading light, because the PDLC becomes transparent or opalescent independent of the polarization state of the reading light when either sufficient or no writing light is incident on the PDLCLV. This device has a limiting resolution of 50 lp/mm (lp indicates line pairs), a reading light efficiency of 60%, a ratio of intensity of light incident on the PDLC layer to intensity of light radiated from the layer, and an extinction ratio of 130:1. The optically addressed video projection system with three PDLCLV's, LC panels of 1048 x 480 pixels as input image sources, a 1-kW Xe lamp, and a schlieren optical system projected television (TV) pictures of 600 and 450 TV lines in the horizontal and the vertical directions on a screen with a diagonal length of 100 in. The total output flux of this system was 1500 lm.

  12. High light induced changes in organization, protein profile and function of photosynthetic machinery in Chlamydomonas reinhardtii.

    PubMed

    Nama, Srilatha; Madireddi, Sai Kiran; Devadasu, Elsin Raju; Subramanyam, Rajagopal

    2015-11-01

    The green alga Chlamydomonas (C.) reinhardtii is used as a model organism to understand the efficiency of photosynthesis along with the organization and protein profile of photosynthetic apparatus under various intensities of high light exposure for 1h. Chlorophyll (Chl) a fluorescence induction, OJIPSMT transient was decreased with increase in light intensity indicating the reduction in photochemical efficiency. Further, circular dichroism studies of isolated thylakoids from high light exposed cells showed considerable change in the pigment-pigment interactions and pigment-proteins interactions. Furthermore, the organization of supercomplexes from thylakoids is studied, in which, one of the hetero-trimer of light harvesting complex (LHC) II is affected significantly in comparison to other complexes of LHC's monomers. Also, other supercomplexes, photosystem (PS)II reaction center dimer and PSI complexes are reduced. Additionally, immunoblot analysis of thylakoid proteins revealed that PSII core proteins D1 and D2 were significantly decreased during high light treatment. Similarly, the PSI core proteins PsaC, PsaD and PsaG were drastically changed. Further, the LHC antenna proteins of PSI and PSII were differentially affected. From our results it is clear that LHCs are damaged significantly, consequently the excitation energy is not efficiently transferred to the reaction center. Thus, the photochemical energy transfer from PSII to PSI is reduced. The inference of the study deciphers the structural and functional changes driven by light may therefore provide plants/alga to regulate the light harvesting capacity in excess light conditions.

  13. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    DOEpatents

    Li, Ting

    2013-08-13

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  14. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    DOEpatents

    Li, Ting [Ventura, CA

    2011-04-26

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  15. PROTON GRADIENT REGULATION5 Is Essential for Proper Acclimation of Arabidopsis Photosystem I to Naturally and Artificially Fluctuating Light Conditions[W

    PubMed Central

    Suorsa, Marjaana; Järvi, Sari; Grieco, Michele; Nurmi, Markus; Pietrzykowska, Malgorzata; Rantala, Marjaana; Kangasjärvi, Saijaliisa; Paakkarinen, Virpi; Tikkanen, Mikko; Jansson, Stefan; Aro, Eva-Mari

    2012-01-01

    In nature, plants are challenged by constantly changing light conditions. To reveal the molecular mechanisms behind acclimation to sometimes drastic and frequent changes in light intensity, we grew Arabidopsis thaliana under fluctuating light conditions, in which the low light periods were repeatedly interrupted with high light peaks. Such conditions had only marginal effect on photosystem II but induced damage to photosystem I (PSI), the damage being most severe during the early developmental stages. We showed that PROTON GRADIENT REGULATION5 (PGR5)–dependent regulation of electron transfer and proton motive force is crucial for protection of PSI against photodamage, which occurred particularly during the high light phases of fluctuating light cycles. Contrary to PGR5, the NAD(P)H dehydrogenase complex, which mediates cyclic electron flow around PSI, did not contribute to acclimation of the photosynthetic apparatus, particularly PSI, to rapidly changing light intensities. Likewise, the Arabidopsis pgr5 mutant exhibited a significantly higher mortality rate compared with the wild type under outdoor field conditions. This shows not only that regulation of PSI under natural growth conditions is crucial but also the importance of PGR5 in PSI protection. PMID:22822205

  16. Propagation of coherent polarized light in turbid highly scattering medium.

    PubMed

    Doronin, Alexander; Macdonald, Callum; Meglinski, Igor

    2014-02-01

    Within the framework of further development of unified Monte Carlo code for the needs of biomedical optics and biophotonics, we present an approach for modeling of coherent polarized light propagation in highly scattering turbid media, such as biological tissues. The temporal coherence of light, linear and circular polarization, interference, and the helicity flip of circularly polarized light due to reflection at the medium boundary and/or backscattering events are taken into account. To achieve higher accuracy in the results and to speed up the modeling, the implementation of the code utilizes parallel computing on NVIDIA graphics processing units using Compute Unified Device Architecture. The results of the simulation of coherent linearly and circularly polarized light are presented in comparison with the results of known theoretical studies and the results of alternative modelings.

  17. Examination of the interaction of different lighting conditions and chronic mild stress in animal model.

    PubMed

    Muller, A; Gal, N; Betlehem, J; Fuller, N; Acs, P; Kovacs, G L; Fusz, K; Jozsa, R; Olah, A

    2015-09-01

    We examined the effects of different shift work schedules and chronic mild stress (CMS) on mood using animal model. The most common international shift work schedules in nursing were applied by three groups of Wistar-rats and a control group with normal light-dark cycle. One subgroup from each group was subjected to CMS. Levels of anxiety and emotional life were evaluated in light-dark box. Differences between the groups according to independent and dependent variables were examined with one- and two-way analysis of variance, with a significance level defined at p < 0.05. Interaction of lighting regimen and CMS was proved to be significant according to time spent in the light compartment and the average number of changes between the light and dark compartments. Results of our examination confirm that the changes of lighting conditions evocate anxiety more prominently than CMS. No significant differences were found between the results of the low rotating group and the control group, supposing that this schedule is the least harmful to health. Our results on the association between the use of lighting regimens and the level of CMS provide evidence that the fast rotating shift work schedule puts the heaviest load on the organism of animals.

  18. Cost and Energy Savings Opportunities with Heating, Air Conditioning and Lighting Systems in Schools.

    ERIC Educational Resources Information Center

    Electric Energy Association, New York, NY.

    Great potential exists for saving energy and operating costs with a wide variety of heat conservation systems. Two major electric services--space conditioning and lighting--afford cost and energy savings opportunities. These services are detailed in checklist fashion in this brochure, with the suggestions included under space conditioning…

  19. Modeling the impact of roadway emissions in light wind, stable and transition conditions

    EPA Science Inventory

    This paper examines the processes that govern air pollution dispersion under light wind, stable and transition conditions by using a state-of-the-art dispersion model to interpret measurements from a tracer experiment conducted next to US highway 99 in Sacramento in 1981–1982 dur...

  20. Modeling the impact of roadway emissions in light wind, stable and transition conditions

    EPA Science Inventory

    This paper examines the processes that govern air pollution dispersion under light wind, stable and transition conditions by using a state-of-the-art dispersion model to interpret measurements from a tracer experiment conducted next to US highway 99 in Sacramento in 1981–1982 dur...

  1. Asymmetric radical alkylation of N-sulfinimines under visible light photocatalytic conditions.

    PubMed

    Garrido-Castro, Alberto F; Choubane, Houcine; Daaou, Mortada; Maestro, M Carmen; Alemán, José

    2017-07-06

    In this communication, a new photocatalytic strategy for the addition of alkyl-radical derivatives to N-sulfinimines with complete diastereoselectivity and moderate to good yields is presented. This is the first asymmetric photocatalytic addition to N-sulfinimines under visible light irradiation with smooth conditions and functional group tolerance.

  2. Carbon and Nitrogen dynamics in forest soils depending on light conditions and tree species

    NASA Astrophysics Data System (ADS)

    Veselinovic, Bojana; Hager, Herbert

    2013-04-01

    Climate change mitigation actions under the Kyoto Protocol apply among other decreases of CO2-emissions and/or increases of carbon (C) stocks. As soils represent the second biggest C-reservoir on Earth, an exact estimation of the stocks and reliable knowledge on C-dynamics in forest soils is of high importance. Anyhow, here, the accurate GHG-accounting, emission reductions and increase in C stocks is hampered due to lack of reliable data and solid statistical methods for the factors which influence C-sequestration in and its release from these systems. In spite of good progress in the scientific research, these factors are numerous and diverse in their interactions. This work focuses on influence of the economically relevant tree species - Picea abies, Fagus sylvatica and Quercus spp. - and light conditions on forest floor and mineral soil C and N dynamics in forest soils. Spruce monocultures have been widely used management practices in central European forests during the past century. Such stands are in lower altitudes and on heavy and water logged soils unstable and prone to disturbances, especially to windthrows. We hypothesize that windthrow areas loose C & N and that the establishment of the previous nutrient stocks is, if at all, only possible to be reached over the longer periods of time. We research also how the increased OM depletion affects the change of C & N stocks in forest floor vs. mineral soil. Conversion of such secondary spruce monocultures to site adequate beech and oak forests may enable higher stocks allocated predominantly as stable organic carbon and as plant available nitrogen. For this purpose sites at 300-700 m altitude with planosols were chosen in the region of the Northern Alpine Foothills. A false chronosequence approach was used in order to evaluate the impacts of the tree species and change in light conditions on dynamic of C & N in the forest floor and mineral soil, over the period 0-100 (for oak 120 y.) years. The C- and N

  3. High-NOON states by mixing quantum and classical light.

    PubMed

    Afek, Itai; Ambar, Oron; Silberberg, Yaron

    2010-05-14

    Precision measurements can be brought to their ultimate limit by harnessing the principles of quantum mechanics. In optics, multiphoton entangled states, known as NOON states, can be used to obtain high-precision phase measurements, becoming more and more advantageous as the number of photons grows. We generated "high-NOON" states (N = 5) by multiphoton interference of quantum down-converted light with a classical coherent state in an approach that is inherently scalable. Super-resolving phase measurements with up to five entangled photons were produced with a visibility higher than that obtainable using classical light only.

  4. Light-weight, high-performance metal matrix composites

    NASA Technical Reports Server (NTRS)

    Rack, H. J.

    1988-01-01

    Recent years have seen the development of a wide range of light-weight, high-performance aluminum powder metallurgy composites that combine both standard (6061 and 2124) and specialty matrix compositions (Al-Mg-Cu-Li and Al-Fe-Ce) with a wide variety of discontinuous reinforcements (Al2O3, B4C, and SiC). This paper reviews the fabrication and damage tolerance performance of these light-weight, high-performance composites. Particular attention is given to developing a general framework for understanding the interrelationship existing between microstructure, thermomechanical processing and ductility/fracture toughness behavior in these composite systems.

  5. Status and Future of High-Power Light-Emitting Diodes for Solid-State Lighting

    NASA Astrophysics Data System (ADS)

    Krames, Michael R.; Shchekin, Oleg B.; Mueller-Mach, Regina; Mueller, Gerd O.; Zhou, Ling; Harbers, Gerard; Craford, M. George

    2007-06-01

    Status and future outlook of III-V compound semiconductor visible-spectrum light-emitting diodes (LEDs) are presented. Light extraction techniques are reviewed and extraction efficiencies are quantified in the 60%+ (AlGaInP) and ~80% (InGaN) regimes for state-of-the-art devices. The phosphor-based white LED concept is reviewed and recent performance discussed, showing that high-power white LEDs now approach the 100-lm/W regime. Devices employing multiple phosphors for “warm” white color temperatures (~3000 4000 K) and high color rendering (CRI > 80), which provide properties critical for many illumination applications, are discussed. Recent developments in chip design, packaging, and high current performance lead to very high luminance devices (~50 Mcd/m2 white at 1 A forward current in 1 x 1 mm2 chip) that are suitable for application to automotive forward lighting. A prognosis for future LED performance levels is considered given further improvements in internal quantum efficiency, which to date lag achievements in light extraction efficiency for InGaN LEDs.

  6. High Efficiency LED Lamp for Solid-State Lighting

    SciTech Connect

    James Ibbetson

    2006-12-31

    This report contains a summary of technical achievements during a three-year project to demonstrate high efficiency, solid-state lamps based on gallium nitride/silicon carbide light-emitting diodes. Novel chip designs and fabrication processes are described for a new type of nitride light-emitting diode with the potential for very high efficiency. This work resulted in the demonstration of blue light-emitting diodes in the one watt class that achieved up to 495 mW of light output at 350 mA drive current, corresponding to quantum and wall plug efficiencies of 51% and 45%, respectively. When combined with a phosphor in Cree's 7090 XLamp package, these advanced blue-emitting devices resulted in white light-emitting diodes whose efficacy exceeded 85 lumens per watt. In addition, up to 1040 lumens at greater than 85 lumens per watt was achieved by combining multiple devices to make a compact white lamp module with high optical efficiency.

  7. High Energy Density Science at the Linac Coherent Light Source

    SciTech Connect

    Lee, R W

    2007-10-19

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded descriptions (Ch. V), and a

  8. Photosynthetic acclimation responses of maize seedlings grown under artificial laboratory light gradients mimicking natural canopy conditions.

    PubMed

    Hirth, Matthias; Dietzel, Lars; Steiner, Sebastian; Ludwig, Robert; Weidenbach, Hannah; And, Jeannette Pfalz; Pfannschmidt, Thomas

    2013-01-01

    In this study we assessed the ability of the C4 plant maize to perform long-term photosynthetic acclimation in an artificial light quality system previously used for analyzing short-term and long-term acclimation responses (LTR) in C3 plants. We aimed to test if this light system could be used as a tool for analyzing redox-regulated acclimation processes in maize seedlings. Photosynthetic parameters obtained from maize samples harvested in the field were used as control. The results indicated that field grown maize performed a pronounced LTR with significant differences between the top and the bottom levels of the plant stand corresponding to the strong light gradients occurring in it. We compared these data to results obtained from maize seedlings grown under artificial light sources preferentially exciting either photosystem II or photosystem I. In C3 plants, this light system induces redox signals within the photosynthetic electron transport chain which trigger state transitions and differential phosphorylation of LHCII (light harvesting complexes of photosystem II). The LTR to these redox signals induces changes in the accumulation of plastid psaA transcripts, in chlorophyll (Chl) fluorescence values F \\rm s/F \\rm m, in Chl a/b ratios and in transient starch accumulation in C3 plants. Maize seedlings grown in this light system exhibited a pronounced ability to perform both short-term and long-term acclimation at the level of psaA transcripts, Chl fluorescence values F \\rm s/F \\rm m and Chl a/b ratios. Interestingly, maize seedlings did not exhibit redox-controlled variations of starch accumulation probably because of its specific differences in energy metabolism. In summary, the artificial laboratory light system was found to be well-suited to mimic field light conditions and provides a physiological tool for studying the molecular regulation of the LTR of maize in more detail.

  9. High light decreases xylem contribution to fruit growth in tomato.

    PubMed

    Hanssens, Jochen; DE Swaef, Tom; Steppe, Kathy

    2015-03-01

    Recently, contradicting evidence has been reported on the contribution of xylem and phloem influx into tomato fruits, urging the need for a better understanding of the mechanisms involved in fruit growth. So far, little research has been performed on quantifying the effect of light intensity on the different contributors to the fruit water balance. However, as light intensity affects both transpiration and photosynthesis, it might be expected to induce important changes in the fruit water balance. In this study, tomato plants (Solanum lycopersicum L.) were grown in light and shade conditions and the fruit water balance was studied by measuring fruit growth of girdled and intact fruits with linear variable displacement transducers combined with a model-based approach. Results indicated that the relative xylem contribution significantly increased when shading lowered light intensity. This resulted from both a higher xylem influx and a lower phloem influx during the daytime. Plants from the shade treatment were able to maintain a stronger gradient in total water potential between stem and fruits during daytime, thereby promoting xylem influx. It appeared that the xylem pathway was still functional at 35 days after anthesis and that relative xylem contribution was strongly affected by environmental conditions.

  10. High-intensity urban light installation dramatically alters nocturnal bird migration.

    PubMed

    Van Doren, Benjamin M; Horton, Kyle G; Dokter, Adriaan M; Klinck, Holger; Elbin, Susan B; Farnsworth, Andrew

    2017-10-02

    Billions of nocturnally migrating birds move through increasingly photopolluted skies, relying on cues for navigation and orientation that artificial light at night (ALAN) can impair. However, no studies have quantified avian responses to powerful ground-based light sources in urban areas. We studied effects of ALAN on migrating birds by monitoring the beams of the National September 11 Memorial & Museum's "Tribute in Light" in New York, quantifying behavioral responses with radar and acoustic sensors and modeling disorientation and attraction with simulations. This single light source induced significant behavioral alterations in birds, even in good visibility conditions, in this heavily photopolluted environment, and to altitudes up to 4 km. We estimate that the installation influenced ≈1.1 million birds during our study period of 7 d over 7 y. When the installation was illuminated, birds aggregated in high densities, decreased flight speeds, followed circular flight paths, and vocalized frequently. Simulations revealed a high probability of disorientation and subsequent attraction for nearby birds, and bird densities near the installation exceeded magnitudes 20 times greater than surrounding baseline densities during each year's observations. However, behavioral disruptions disappeared when lights were extinguished, suggesting that selective removal of light during nights with substantial bird migration is a viable strategy for minimizing potentially fatal interactions among ALAN, structures, and birds. Our results also highlight the value of additional studies describing behavioral patterns of nocturnally migrating birds in powerful lights in urban areas as well as conservation implications for such lighting installations.

  11. Diurnal photosynthesis, water use efficiency and light use efficiency of wheat under Mediterranean field conditions.

    PubMed

    Evrendilek, Fatih; Ben Asher, Jiftah; Aydin, Mehmet

    2008-05-01

    Photosynthesis and transpiration rates of wheat leaves (Triticum aestivum L.) were measured at 30 min intervals under Mediterranean field conditions, using Photosynthesis Monitor system (PM-48M). The dynamics of net photosynthetic rate (P(N)), transpiration rate (E(T)), water use efficiency (WUE), light use efficiency (LUE), stomatal conductance (g(s)), photosynthetically active radiation (PAR), air temperature (T), relative humidity (RH), and atmospheric CO2 concentration (Catm) were quantified at five rainfed wheat sites with the same stages of development (midflowering) along south-to-north and east-to-west transects for eight days in April. Diurnal P(N) (3.6 to 6.6 micromol m(-2) s(-1)), PAR (392 to 564 micromol m2 sec(-1)), LUE (0.006 to 0.015) and WUE (0.0001 to 0.011) did not vary significantly across all five wheat sites (p > 0.05). P(N) and E(T) were strongly coupled and highly correlated with PAR (p < 0.001). Best multiple linear regression (MLR) models accounted for 92% of variations in P(N) as a function of PAR and E(T), and 90% in E(T) as a function of PAR and RH (p < 0.001). P(N) exhibited a peak at mid-morning, and a photosynthetic midday depression under the limiting effects of high evaporative demand. Diurnal variations in WUE and LUE showed a bimodal behavior with the maximum values in early morning and late afternoon. As the impacts of global climate change become increasingly felt, continuous measurements of climate-crop-soil-managementinteractions under natural conditions play a pivotal role not only in exploring changes in ecophysiological properties of strategic crops for food security such as wheat but also in devising preventive and mitigative management practices to ensure sustained agricultural productivity.

  12. High-performance OLEDs and their application to lighting

    NASA Astrophysics Data System (ADS)

    Ide, Nobuhiro; Tsuji, Hiroya; Ito, Norihiro; Sasaki, Hiroyuki; Nishimori, Taisuke; Kuzuoka, Yoshikazu; Fujihara, Koki; Miyai, Takao; Komoda, Takuya

    2008-08-01

    Organic light emitting diodes (OLED) are expected to be used in next generation solid state lighting sources serving as an alternative to conventional incandescent bulbs and fluorescent lamps. OLEDs will provide the environmental benefits of possible considerable energy savings and elimination of mercury, as well as some other advantages such as thin flat shape, planar emission, and no UV emission. Recently, important properties of OLEDs such as efficiency and lifetime have been greatly improved. Additionally, for lighting applications, a high color rendering index (CRI) at the desired CIE chromaticity coordinates, high luminance and large area uniform emission, and high stability over long time operation are also required. In this paper, we describe the development and performance of our high CRI OLEDs: the conventional OLED with multiple emissive layers and the multi-unit OLED with only two emissive units (a fluorescent blue emissive unit and a phosphorescent green / red emissive unit). Related technologies for OLED lighting to obtain uniform emission at high luminance in large areas are also described.

  13. High efficiency air cycle air conditioning system

    SciTech Connect

    Rannenberg, G. C.

    1985-11-19

    An air cycle air conditioning system is provided with regenerative heat exchangers upstream and downstream of an expansion turbine. A closedloop liquid circulatory system serially connects the two regenerative heat exchangers for regeneration without the bulk associated with air-to-air heat exchange. The liquid circulatory system may also provide heat transport to a remote sink heat exchanger and from a remote load as well as heat exchange within the sink heat exchanger and load for enhanced compactness and efficiency.

  14. High resolution map of light pollution over Poland

    NASA Astrophysics Data System (ADS)

    Netzel, Henryka; Netzel, Paweł

    2016-09-01

    In 1976 Berry introduced a simple mathematical equation to calculate artificial night sky brightness at zenith. In the original model cities, considered as points with given population, are only sources of light emission. In contrary to Berry's model, we assumed that all terrain surface can be a source of light. Emission of light depends on percent of built up area in a given cell. We based on Berry's model. Using field measurements and high-resolution data we obtained the map of night sky brightness over Poland in 100-m resolution. High resolution input data, combined with a very simple model, makes it possible to obtain detailed structures of the night sky brightness without complicating the calculations.

  15. Strontium and barium iodide high light yield scintillators

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Hull, Giulia; Drobshoff, Alexander D.; Payne, Stephen A.; van Loef, Edgar; Wilson, Cody M.; Shah, Kanai S.; Roy, Utpal N.; Burger, Arnold; Boatner, Lynn A.; Choong, Woon-Seng; Moses, William W.

    2008-02-01

    Europium-doped strontium and barium iodide are found to be readily growable by the Bridgman method and to produce high scintillation light yields. SrI2(Eu ) emits into the Eu2+ band, centered at 435nm, with a decay time of 1.2μs and a light yield of ˜90000photons/MeV. It offers energy resolution better than 4% full width at half maximum at 662keV, and exhibits excellent light yield proportionality. BaI2(Eu ) produces >30000photons/MeV into the Eu2+ band at 420nm (<1μs decay). An additional broad impurity-mediated recombination band is present at 550nm (>3μs decay), unless high-purity feedstock is used.

  16. Implementation of focusing and redirecting light through highly scattering media

    NASA Astrophysics Data System (ADS)

    Coyotl-Ocelotl, B.; Porras-Aguilar, R.; Ramos-Garcia, R.; Ramirez-San-Juan, J. C.

    2015-08-01

    Optical imaging through highly scattering media such as biological tissue is limited by light scattering. Recently, it has been shown that wavefront shaping is a powerful tool to overcome this problem. In this work, wavefront shaping using spatial light modulators is used to compensate static scattering media (piece of translucent tape) to allow focusing of different intensity distributions. Light propagation is engineered into a specific region of interest. For this purpose, a sequential phase shape algorithm was implemented experimentally. This algorithm is used to encode a phase distribution on an incident beam to pre-compensate phase distortions acquired by the beam after propagating through the tape. The sequential algorithm combined with a spatial light modulator is used to synthesize a phase distribution required for redirecting light using wavefront shaping. The scattered light was re-directed at the detector plane, in order to be: i) focused at a single pixel, ii) at squared regions of 3×3 and 5×5 pixeles and iii) a line pattern of 41 pixels of the camera. Furthermore, the region of interest was placed outside the central area of the camera opening the possibility of image formation.

  17. New technologies in lighting systems for high-speed film and photography regarding high-intensity and heat problems

    NASA Astrophysics Data System (ADS)

    Severon, Burkhard

    1991-04-01

    Increasing frame rates and the heat sensibility of test objects forced the development of new lighting systems. For example at the automotive industry, where continuous light sources are indispensable for the high speed photography of car crash tests and automobile components tests, the further development of high efficient safety systems, so as Air-Bag systems, needs very datailed analysis of the accelerated motions. Frame rates from 2.000 up to 10.000 frames per second are requested and beside adequate camera systems and film material, this also means high intensive lighting systems. The need for high intensity could be easy achieved by the use of additional light fixtures but the request for more intensity comes along with the problem of heat. The test objects and the auxiliary materials become more and more temperature- sensitive. Very offen they have to be used under strict climate conditions. Mainly there where the test objects are already placed inside the illuminated area, the heat radiation of the light sources to the test objects have to be reduced. So high intensive, flicker free and less heat are today's requirements of light performance. This paper will present solutions to meet those demands.

  18. Highly stable superhydrophobic surfaces under flow conditions

    NASA Astrophysics Data System (ADS)

    Lee, Moonchan; Yim, Changyong; Jeon, Sangmin

    2015-01-01

    We synthesized hydrophobic anodic aluminum oxide nanostructures with pore diameters of 35, 50, 65, and 80 nm directly on quartz crystal microresonators, and the stability of the resulting superhydrophobicity was investigated under flow conditions by measuring changes in the resonance frequency and dissipation factor. When the quartz substrates were immersed in water, their hydrophobic surfaces did not wet due to the presence of an air interlayer. The air interlayer was gradually replaced by water over time, which caused decreases in the resonance frequency (i.e., increases in mass) and increases in the dissipation factor (i.e., increases in viscous damping). Although the water contact angles of the nanostructures increased with increasing pore size, the stability of their superhydrophobicity increased with decreasing pore size under both static conditions (without flow) and dynamic conditions (with flow); this increase can be attributed to an increase in the solid surface area that interacts with the air layer above the nanopores as the pore size decreases. Further, the effects of increasing the flow rate on the stability of the superhydrophobicity were quantitatively determined.

  19. Different colors of light lead to different adaptation and activation as determined by high-density EEG.

    PubMed

    Münch, M; Plomp, G; Thunell, E; Kawasaki, A; Scartezzini, J L; Herzog, M H

    2014-11-01

    Light adaptation is crucial for coping with the varying levels of ambient light. Using high-density electroencephalography (EEG), we investigated how adaptation to light of different colors affects brain responsiveness. In a within-subject design, sixteen young participants were adapted first to dim white light and then to blue, green, red, or white bright light (one color per session in a randomized order). Immediately after both dim and bright light adaptation, we presented brief light pulses and recorded event-related potentials (ERPs). We analyzed ERP response strengths and brain topographies and determined the underlying sources using electrical source imaging. Between 150 and 261 ms after stimulus onset, the global field power (GFP) was higher after dim than bright light adaptation. This effect was most pronounced with red light and localized in the frontal lobe, the fusiform gyrus, the occipital lobe and the cerebellum. After bright light adaptation, within the first 100 ms after light onset, stronger responses were found than after dim light adaptation for all colors except for red light. Differences between conditions were localized in the frontal lobe, the cingulate gyrus, and the cerebellum. These results indicate that very short-term EEG brain responses are influenced by prior light adaptation and the spectral quality of the light stimulus. We show that the early EEG responses are differently affected by adaptation to different colors of light which may contribute to known differences in performance and reaction times in cognitive tests.

  20. Characterization of light-dependent hydrogen production by new green microalga Parachlorella kessleri in various conditions.

    PubMed

    Gabrielyan, Lilit; Hakobyan, Lusine; Trchounian, Armen

    2017-10-01

    Nowadays, hydrogen (H2) production by green microalgae seems to be a very perspective, as stocks of water and solar energy are practically inexhaustible and renewable. The aim of this study was the optimization of conditions (organic carbon sources and lighting regime), which can provide light-dependent H2 production by green microalga Parachlorella kessleri RA-002 newly isolated in Armenia. The results indicated that carbon sources and lighting regimes affected H2 production. In the presence of used carbon sources H2 production was observed, but the highest yield of H2 was obtained in the presence of acetate. It was 2-fold higher than the H2 yield determined in the presence of glucose. The increase of H2 production might be connected with the stimulation of H2-producing enzyme - [Fe]-hydrogenase synthesis. The data obtained show that acetate can be used as an effective carbon source in H2 production. H2 production by microalga (in the presence of acetate and glucose) was enhanced by 1.5-2.5-fold in comparison with continuously illuminated algal cells, when P. kessleri was illuminated during 24h, and then was moved in the darkness. H2 yield increase is possible due to hydrogenase activation and the creation of anaerobic conditions. This study was significant to find out available effective substrates and optimal lighting regime to provide with light-dependent H2 production by microalgae. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Individual differences in circadian waveform of Siberian hamsters under multiple lighting conditions.

    PubMed

    Evans, Jennifer A; Elliott, Jeffrey A; Gorman, Michael R

    2012-10-01

    Because the circadian clock in the mammalian brain derives from a network of interacting cellular oscillators, characterizing the nature and bases of circadian coupling is fundamental to understanding how the pacemaker operates. Various phenomena involving plasticity in circadian waveform have been theorized to reflect changes in oscillator coupling; however, it remains unclear whether these different behavioral paradigms reference a unitary underlying process. To test whether disparate coupling assays index a common mechanism, we examined whether there is covariation among behavioral responses to various lighting conditions that produce changes in circadian waveform. Siberian hamsters, Phodopus sungorus, were transferred from long to short photoperiods to distinguish short photoperiod responders (SP-R) from nonresponders (SP-NR). Short photoperiod chronotyped hamsters were subsequently transferred, along with unselected controls, to 24-h light:dark:light: dark cycles (LDLD) with dim nighttime illumination, a procedure that induces bifurcated entrainment. Under LDLD, SP-R hamsters were more likely to bifurcate their rhythms than were SP-NR hamsters or unselected controls. After transfer from LDLD to constant dim light, SP-R hamsters were also more likely to become arrhythmic compared to SP-NR hamsters and unselected controls. In contrast, short photoperiod chronotype did not influence more transient changes in circadian waveform. The present data reveal a clear relationship in the plasticity of circadian waveform across 3 distinct lighting conditions, suggesting a common mechanism wherein individual differences reflect variation in circadian coupling.

  2. The study of LED light source illumination conditions for ideal algae cultivation

    NASA Astrophysics Data System (ADS)

    Tsai, Chun-Chin; Huang, Chien-Fu; Chen, Cin-Fu; Yue, Cheng-Feng

    2017-02-01

    Utilizing LED light source modules with 3 different RGB colors, the illumination effect of different wavelengths had been investigated on the growth curve of the same kind of micro algae. It was found that the best micro algae culturing status came out with long wavelength light such as red light (650 670 nm). Based on the same condition for a period of 3 weeks , the grown micro algae population density ratio represented by Optical Density (O.D.) ratio is 1?0.4?0.7 corresponding to growth with Red, Green, Blue light sources, respectively. Mixing 3 types and 2 types of LEDs with different parameters, the grown micro algae population densities were compared in terms of O.D. Interestingly enough, different light sources resulted in significant discoloration on micro algae growth, appearing yellow, brown, green, etc. Our experiments results showed such discoloration effect is reversible. Based on the same lighting condition, micro algae growth can be also affected by incubator size, nutrition supply, and temperature variation. In recent years, micro algae related technologies have been international wise a hot topic of energy and environmental protection for research and development institutes, and big energy companies among those developed countries. There will be an economically prosperous future. From this study of LED lighting to ideal algae cultivation, it was found that such built system would be capable of optimizing artificial cultivation system, leading to economic benefits for its continuous development. Since global warming causing weather change, accompanying with reducing energy sources and agriculture growth shortage are all threatening human being survival.

  3. Simplified Generation of High-Angular-Momentum Light Beams

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Strekalov, Dmitry; Grudinin, Ivan

    2007-01-01

    A simplified method of generating a beam of light having a relatively high value of angular momentum (see figure) involves the use of a compact apparatus consisting mainly of a laser, a whispering- gallery-mode (WGM) resonator, and optical fibers. The method also can be used to generate a Bessel beam. ( Bessel beam denotes a member of a class of non-diffracting beams, so named because their amplitudes are proportional to Bessel functions of the radii from their central axes. High-order Bessel beams can have high values of angular momentum.) High-angular-momentum light beams are used in some applications in biology and nanotechnology, wherein they are known for their ability to apply torque to make microscopic objects rotate. High-angular-momentum light beams could also be used to increase bandwidths of fiber-optic communication systems. The present simplified method of generating a high-angular-momentum light beam was conceived as an alternative to prior such methods, which are complicated and require optical setups that include, variously, holograms, modulating Fabry-Perot cavities, or special microstructures. The present simplified method exploits a combination of the complex structure of the electromagnetic field inside a WGM resonator, total internal reflection in the WGM resonator, and the electromagnetic modes supported by an optical fiber. The optical fiber used to extract light from the WGM resonator is made of fused quartz. The output end of this fiber is polished flat and perpendicular to the fiber axis. The input end of this fiber is cut on a slant and placed very close to the WGM resonator at an appropriate position and orientation. To excite the resonant whispering- gallery modes, light is introduced into the WGM resonator via another optical fiber that is part of a pigtailed fiber-optic coupler. Light extracted from the WGM resonator is transformed into a high-angular- momentum beam inside the extraction optical fiber and this beam is emitted from the

  4. Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions.

    PubMed

    Lima, Vandimilli A; Pacheco, Fernanda V; Avelar, Rafaella P; Alvarenga, Ivan C A; Pinto, José Eduardo B P; Alvarenga, Amauri A DE

    2017-01-01

    Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN) and blue (BN) both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade). The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

  5. The classical theory of dispersion of high-intensity light

    SciTech Connect

    Kozlov, S.A.

    1995-08-01

    The dependence of the nonlinear refractive index of an optical medium on the optical wave frequency in the classical theory of dispersion of high-intensity light is shown to have the same form as in the quantum theory if a structural unit of substance in the Lorentz model is considered as two parametrically coupled nonlinear oscillators rather than one oscillator. 13 refs.

  6. Light-intensity modulator withstands high heat fluxes

    NASA Technical Reports Server (NTRS)

    Maples, H. G.; Strass, H. K.

    1966-01-01

    Mechanism modulates and controls the intensity of luminous radiation in light beams associated with high-intensity heat flux. This modulator incorporates two fluid-cooled, externally grooved, contracting metal cylinders which when rotated about their longitudinal axes present a circular aperture of varying size depending on the degree of rotation.

  7. Overexpression of Glycolate Oxidase Confers Improved Photosynthesis under High Light and High Temperature in Rice.

    PubMed

    Cui, Li-Li; Lu, Yu-Sheng; Li, Yong; Yang, Chengwei; Peng, Xin-Xiang

    2016-01-01

    While glycolate oxidase (GLO) is well known as a key enzyme for the photorespiratory metabolism in plants, its physiological function and mechanism remains to be further clarified. Our previous studies have shown that suppression of GLO in rice leads to stunted growth and inhibited photosynthesis (Pn) which is positively and linearly correlated with decreased GLO activities. It is, therefore, of interest to further understand whether Pn can be improved when GLO is up-regulated? In this study, four independent overexpression rice lines, with gradient increases in GLO activity, were generated and functionally analyzed. Phenotypic observations showed that the growth could be improved when GLO activities were increased by 60 or 100%, whereas reduced growth was noticed when the activity was further increased by 150 or 210%. As compared with WT plants, all the overexpression plants exhibited significantly improved Pn under conditions of high light and high temperature, but not under normal conditions. In addition, the overexpression plants were more resistant to the MV-induced photooxidative stress. It was further demonstrated that the antioxidant enzymes, and the antioxidant metabolite glutathione was not significantly altered in the overexpression plants. In contrast, H2O2 and salicylic acid (SA) were correspondingly induced upon the GLO overexpression. Taken together, the results suggest that GLO may play an important role for plants to cope with high light and high temperature, and that H2O2 and SA may serve as signaling molecules to trigger stress defense responses but antioxidant reactions appear not to be involved in the defense.

  8. Overexpression of Glycolate Oxidase Confers Improved Photosynthesis under High Light and High Temperature in Rice

    PubMed Central

    Cui, Li-Li; Lu, Yu-sheng; Li, Yong; Yang, Chengwei; Peng, Xin-Xiang

    2016-01-01

    While glycolate oxidase (GLO) is well known as a key enzyme for the photorespiratory metabolism in plants, its physiological function and mechanism remains to be further clarified. Our previous studies have shown that suppression of GLO in rice leads to stunted growth and inhibited photosynthesis (Pn) which is positively and linearly correlated with decreased GLO activities. It is, therefore, of interest to further understand whether Pn can be improved when GLO is up-regulated? In this study, four independent overexpression rice lines, with gradient increases in GLO activity, were generated and functionally analyzed. Phenotypic observations showed that the growth could be improved when GLO activities were increased by 60 or 100%, whereas reduced growth was noticed when the activity was further increased by 150 or 210%. As compared with WT plants, all the overexpression plants exhibited significantly improved Pn under conditions of high light and high temperature, but not under normal conditions. In addition, the overexpression plants were more resistant to the MV-induced photooxidative stress. It was further demonstrated that the antioxidant enzymes, and the antioxidant metabolite glutathione was not significantly altered in the overexpression plants. In contrast, H2O2 and salicylic acid (SA) were correspondingly induced upon the GLO overexpression. Taken together, the results suggest that GLO may play an important role for plants to cope with high light and high temperature, and that H2O2 and SA may serve as signaling molecules to trigger stress defense responses but antioxidant reactions appear not to be involved in the defense. PMID:27540387

  9. Nanoimprint lithography for green water-repellent film derived from biomass with high-light transparency

    NASA Astrophysics Data System (ADS)

    Takei, Satoshi; Hanabata, Makoto

    2015-03-01

    Newly eco-friendly high light transparency film with plant-based materials was investigated to future development of liquid crystal displays and optical devices with water repellency as a chemical design concept of nanoimprint lithography. This procedure is proven to be suitable for material design and the process conditions of ultraviolet curing nanoimprint lithography for green water-repellent film derived from biomass with high-light transparency. The developed formulation of advanced nanoimprinted materials design derived from lactulose and psicose, and the development of suitable UV nanoimprint conditions produced high resolutions of the conical shaped moth-eye regularly-nanostructure less than approximately 200 nm diameter, and acceptable patterning dimensional accuracy by the replication of 100 times of UV nanoimprint lithography cycles. The newly plant-based materials and the process conditions are expected as one of the defect less nanoimprint lithographic technologies in next generation electronic devices.

  10. Light energy allocation at PSII under field light conditions: how much energy is lost in NPQ-associated dissipation?

    PubMed

    Endo, Tsuyoshi; Uebayashi, Nozomu; Ishida, Satoshi; Ikeuchi, Masahiro; Sato, Fumihiko

    2014-08-01

    In the field, plants are exposed to fluctuating light, where photosynthesis occurs under conditions far from a steady state. Excess energy dissipation associated with energy quenching of chlorophyll fluorescence (qE) functions as an efficient photo-protection mechanism in photosystem II. PsbS is an important regulator of qE, especially for the induction phase of qE. Beside the regulatory energy dissipation, some part of energy is lost through relaxation of excited chlorophyll molecules. To date, several models to quantify energy loss through these dissipative pathways in PSII have been proposed. In this short review, we compare and evaluate these models for PSII energy allocation when they are applied to non-steady state photosynthesis. As a case study, an investigation on energy allocation to qE-associated dissipation at PSII under non-steady state photosynthesis using PsbS-deficient rice transformants is introduced. Diurnal and seasonal changes in PSII energy allocation in rice under natural light are also presented. Future perspective of studies on PSII energy allocation is discussed.

  11. Optical power splitter for splitting high power light

    DOEpatents

    English, R.E. Jr.; Christensen, J.J.

    1995-04-18

    An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is substantially coaxial to the central axis is incident on the prisms and at least partially strikes a surface area of each prism input face. The incident beam also partially passes through the central channel. 5 figs.

  12. Optical power splitter for splitting high power light

    DOEpatents

    English, Jr., Ronald E.; Christensen, John J.

    1995-01-01

    An optical power splitter for the distribution of high-power light energy has a plurality of prisms arranged about a central axis to form a central channel. The input faces of the prisms are in a common plane which is substantially perpendicular to the central axis. A beam of light which is substantially coaxial to the central axis is incident on the prisms and at least partially strikes a surface area of each prism input face. The incident beam also partially passes through the central channel.

  13. N-formylkynurenine as a marker of high light stress in photosynthesis.

    PubMed

    Dreaden, Tina M; Chen, Jun; Rexroth, Sascha; Barry, Bridgette A

    2011-06-24

    Photosystem II (PSII) is the membrane protein complex that catalyzes the photo-induced oxidation of water at a manganese-calcium active site. Light-dependent damage and repair occur in PSII under conditions of high light stress. The core reaction center complex is composed of the D1, D2, CP43, and CP47 intrinsic polypeptides. In this study, a new chromophore formed from the oxidative post-translational modification of tryptophan is identified in the CP43 subunit. Tandem mass spectrometry peptide sequencing is consistent with the oxidation of the CP43 tryptophan side chain, Trp-365, to produce N-formylkynurenine (NFK). Characterization with ultraviolet visible absorption and ultraviolet resonance Raman spectroscopy supports this assignment. An optical assay suggests that the yield of NFK increases 2-fold (2.2 ± 0.5) under high light illumination. A concomitant 2.4 ± 0.5-fold decrease is observed in the steady-state rate of oxygen evolution under the high light conditions. NFK is the product formed from reaction of tryptophan with singlet oxygen, which can be produced under high light stress in PSII. Reactive oxygen species reactions lead to oxidative damage of the reaction center, D1 protein turnover, and inhibition of electron transfer. Our results are consistent with a role for the CP43 NFK modification in photoinhibition.

  14. High light acclimation of Chromera velia points to photoprotective NPQ.

    PubMed

    Belgio, Erica; Trsková, Eliška; Kotabová, Eva; Ewe, Daniela; Prášil, Ondřej; Kaňa, Radek

    2017-04-12

    It has previously been shown that the long-term treatment of Arabidopsis thaliana with the chloroplast inhibitor lincomycin leads to photosynthetic membranes enriched in antennas, strongly reduced in photosystem II reaction centers (PSII) and with enhanced nonphotochemical quenching (NPQ) (Belgio et al. Biophys J 102:2761-2771, 2012). Here, a similar physiological response was found in the microalga Chromera velia grown under high light (HL). In comparison to cells acclimated to low light, HL cells displayed a severe re-organization of the photosynthetic membrane characterized by (1) a reduction of PSII but similar antenna content; (2) partial uncoupling of antennas from PSII; (3) enhanced NPQ. The decrease in the number of PSII represents a rather unusual acclimation response compared to other phototrophs, where a smaller PSII antenna size is more commonly found under high light. Despite the diminished PSII content, no net damage could be detected on the basis of the Photosynthesis versus irradiance curve and electron transport rates pointing at the excess capacity of PSII. We therefore concluded that the photoinhibition is minimized under high light by a lower PSII content and that cells are protected by NPQ in the antennas.

  15. Laser surface texturization for high power cladding light stripper

    NASA Astrophysics Data System (ADS)

    Berisset, Michael; Lebrun, Léo.; Faucon, Marc; Kling, Rainer; Boullet, Johan; Aguergaray, Claude

    2016-03-01

    We demonstrated herein a new type of cladding light strippers suitable for high power systems. By precisely micro-machining the surface of the fiber we create CLS with efficiencies as high as 97 % for large NA, multi-mode, cladding light (NA = 0.3), and 70 % for single-mode, low NA, light. The NA of the cladding light is reduced from 0.3 down to 0.08. The CLS exhibit a 1°C/stripped-Watt temperature elevation making them very suitable for high power applications. This fabrication method is simple and reliable. We have tested different texturization geometries on several different fibers: 20/400 from Nufern, KAGOME, and LMA 10 and LMA 15 fibers (results not shown herein) and we observed good efficiencies and temperature elevation behavior for all of them. Finally, large scale production of CLS with this method is possible since the time necessary to prepare on CLS is very small, in the order of few seconds.

  16. Modeling light and temperature influence on ammonium removal by Scenedesmus sp. under outdoor conditions.

    PubMed

    Ruiz-Martínez, Ana; Serralta, Joaquin; Seco, Aurora; Ferrer, Jose

    2016-10-01

    The ammonium removal rate of the microalga Scenedesmus sp. was studied under outdoor conditions. Microalgae were grown in a 500 L flat-plate photobioreactor and fed with the effluent of a submerged anaerobic membrane bioreactor. Temperature ranged between 9.5 °C and 32.5 °C and maximum light intensity was 1,860 μmol·m(-2)·s(-1). A maximum specific ammonium removal rate of 3.71 mg NH4(+)-N·g TSS(-1)·h(-1) was measured (at 22.6 °C and with a light intensity of 1,734 μmol·m(-2)·s(-1)). A mathematical model considering the influence of ammonium concentration, light and temperature was validated. The model successfully reproduced the observed values of ammonium removal rate obtained and it is thus presented as a useful tool for plant operation.

  17. Optical anisotropy of cubic photonic crystals under conditions of multiple-mode light propagation

    NASA Astrophysics Data System (ADS)

    Ukleev, T. A.; Yurasova, D. I.; Shevchenko, N. N.; Sel'kin, A. V.

    2016-11-01

    Bragg reflection spectra of light are studied for opal-like photonic crystals made of polystyrene spheres. A resonant enhancement of reflectivity is observed in cross-polarization configuration of the analyzer and polarizer when varying the azimuthal orientation of a sample in respect to the incidence plane. The cross-polarization effect takes place at oblique incidence of light on the lateral (111) crystal plane with the plane of incidence being non-perpendicular to the inclined (11-1) crystal plane. The effect is shown to be due to the multiple Bragg diffraction of light when the resonant Bragg conditions are fulfilled at a certain angle of incidence and azimuth for the lateral and inclined crystal planes simultaneously.

  18. Stress response of OsETHE1 is altered in response to light and dark conditions.

    PubMed

    Kaur, Charanpreet; Singla-Pareek, Sneh Lata; Sopory, Sudhir K

    2014-01-01

    ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1), encoding sulfur dioxygenase activity is believed to be an important candidate in sulfur metabolism, where it is involved in amino acid catabolism during carbohydrate starvation and embryo development as seen in Arabidopsis thaliana. OsETHE1, an ETHE1-encoding gene from rice, is in fact induced in response to abiotic stresses, condition which affects nutritional status of the plant, reflecting the need for nutrient remobilization. Sulfur reduction and assimilation are believed to be light-dependent processes and so the genes involved in sulfur oxidation must also be investigated for light-dependent regulatory effects. To this end, we show that the stress response of OsETHE1 is dependent on light and that darkness largely suppresses the stress response of this gene. However, the observed regulatory effect is intricate, varying according to the stress imposed; thereby suggesting the involvement of various aspects of signaling in this process.

  19. Alteration of media composition and light conditions change morphology, metabolic profile, and beauvericin biosynthesis in Cordyceps bassiana mycelium.

    PubMed

    Hyun, Sun-Hee; Lee, Seok-Young; Park, Shin Jung; Kim, Da Yeon; Chun, Young-Jin; Sung, Gi-Ho; Kim, Seong Hwan; Choi, Hyung-Kyoon

    2013-01-01

    Metabolic alterations of Cordyceps bassiana mycelium were investigated under the following culture medium and light conditions: dextrose agar supplemented with 0.5% yeast extract (SDAY) medium with light (SL), SDAY medium without light (SD), nut medium without light (ND), and iron-supplemented SDAY medium without light (FD). The levels of asparagine, aspartic acid, glutamic acid, glutamine, histidine, lysine, ornithine, and proline were significantly higher under SD and SL conditions. The levels of most of the alcohols, saturated fatty acids, unsaturated fatty acids, fatty acid esters, sterols, and terpenes were higher under the ND condition than in the other conditions, but beauvericin was not detectable under the ND condition. The FD condition was favorable for the enhanced production of aminomalonic acid, malic acid, mannonic acid, and erythritol. Thus, the metabolic characteristics of C. bassiana can be manipulated by varying the cultivation conditions, rendering this fungus potentially favorable as a nutraceutical and medicinal resource.

  20. High-Efficiency Nitride-Based Solid-State Lighting

    SciTech Connect

    Paul T. Fini; Shuji Nakamura

    2005-07-30

    In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 {micro}m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of {approx} 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light emitting diodes, and packaging them to produce a white

  1. 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.

  2. The influence of canopy, sky condition, and solar angle on light quality in a longleaf pine woodland

    Treesearch

    Stephen D. Pecot; Stephen B. Horsley; Michael A. Battaglia; Robert J. Mitchell

    2005-01-01

    Light transmittance estimates under open, heterogeneous woodland canopies such as those of longleaf pine (Pinus palustris Mill.) forests report high spatial and temporal variation in the quantity of the light environment. In addition, light quality, that is, the ratio of red to far-red light (R:FR), regulates important aspects of plant...

  3. The high-order quantum coherence of thermal light

    NASA Astrophysics Data System (ADS)

    Chen, Hui

    Thermal light, such as sunlight, is usually considered classical light. In a macroscopic picture, classical theory successfully explained the first-order coherence phenomena of thermal light. The macroscopic theory, based on the statistical behavior of light intensity fluctuations, however, can only phenomenologically explain the second- or higher-order coherence phenomena of thermal light. This thesis introduces a microscopic quantum picture, based on the interferences of a large number of randomly distributed and randomly radiated subfields, wavepackets or photons, to the study of high-order coherence of thermal light. This thesis concludes that the second-order intensity fluctuation correlation is caused by nonlocal interference: a pair of wavepackets, which are randomly paired together, interferes with the pair itself at two distant space-time coordinates. This study has the following practical motivations: (1) to simulate N-qbits. Practical quantum computing requires quantum bits(qubits) of N-digit to represent all possible integers from 0 to 2N-1 simultaneously. A large number of independent particles can be prepared to represent a large set of N orthogonal |0> and |1> bits. In fact, based on our recent experiments of simulating the high-order correlation of entangled photons, thermal radiation is suggested as a promising source for quantum information processing. (2) to achieve sunlight ghost imaging. Ghost imaging has three attractive non-classical features: (a) the ghost camera can "see" targets that can never be seen by a classic camera; (2) it is turbulence-free; and (3) its spatial resolution is mainly determined by the angular diameter of the light source. For example, a sunlight ghost image of an object on earth may achieve a spatial resolution of 200 micrometer because the angular diameter of sun is 0.53 degree with respect to Earth. Although ghost imaging has been experimental demonstrated by using entangled photon pairs and "pseudo-thermal light

  4. Modes of antibacterial action of curcumin under dark and light conditions: A toxicoproteomics approach.

    PubMed

    Shlar, Ilya; Droby, Samir; Rodov, Victor

    2017-03-15

    Curcumin is a potent natural food-grade antimicrobial compound. Exposure to light further enhances its antimicrobial capacity. Proteomic methods were used in this study for investigating the mechanistic aspects of the antibacterial curcumin effects in the dark and upon illumination. Escherichia coli cells exposed to water-dispersible curcumin-methyl-β-cyclodextrin inclusion complex under dark and light conditions were compared with the non-treated cells kept under the same illumination regimes. Curcumin treatment in the dark evoked adaptive responses aimed at mitigation of oxidative stress, DNA protection, proteostasis, modulation of redox state via changing NADH level, and gasotransmitter (H2S and NH3) biosynthesis. Although part of these phenomena were also present in E. coli treated under light, the light-induced curcumin toxicity was prevailed by maladaptive responses. The ROS burst induced upon curcumin treatment under light overrode the cellular adaptive mechanisms disrupting the iron metabolism, deregulating the iron-sulfur cluster biosynthesis and eventually leading to cell death. The toxicoproteomic findings were validated by transcriptomic analysis and by assessment of intracellular ROS, NADH, NADPH and iron levels.

  5. 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.

  6. On final conditions in high energy heavy ion Collisions

    SciTech Connect

    Sinyukov, Yu.M.; Akkelin, S.V.; Xu, N.

    1998-06-01

    Motivated by the recent experimental observations, wediscuss the freeze-out properties of the fireball created in centralheavy ion collisions. We find that the freeze-out conditions, liketemperature, velocity gradient near center of the fireball, are similarfor different colliding systems and beam energies. This means that thetransverse flow is stronger in the collisions of heavy nuclei than thatof the light ones.

  7. NANOSTRUCTURED HIGH PERFORMANCE ULTRAVIOLET AND BLUE LIGHT EMITTING DIODES FOR SOLID STATE LIGHTING

    SciTech Connect

    Arto V. Nurmikko; Jung Han

    2004-10-01

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the first 12 month contract period include (1) new means of synthesizing zero- and one-dimensional GaN nanostructures, (2) establishment of the building blocks for making GaN-based microcavity devices, and (3) demonstration of top-down approach to nano-scale photonic devices for enhanced spontaneous emission and light extraction. These include a demonstration of eight-fold enhancement of the external emission efficiency in new InGaN QW photonic crystal structures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  8. Energy Harvesting for GaAs Photovoltaics Under Low-Flux Indoor Lighting Conditions.

    PubMed

    Teran, Alan S; Moon, Eunseong; Lim, Wootaek; Kim, Gyouho; Lee, Inhee; Blaauw, David; Phillips, Jamie D

    2016-07-01

    GaAs photovoltaics are promising candidates for indoor energy harvesting to power small-scale (≈1 mm(2)) electronics. This application has stringent requirements on dark current, recombination, and shunt leakage paths due to low-light conditions and small device dimensions. The power conversion efficiency and the limiting mechanisms in GaAs photovoltaic cells under indoor lighting conditions are studied experimentally. Voltage is limited by generation-recombination dark current attributed to perimeter sidewall surface recombination based on the measurements of variable cell area. Bulk and perimeter recombination coefficients of 1.464 pA/mm(2) and 0.2816 pA/mm, respectively, were extracted from dark current measurements. Resulting power conversion efficiency is strongly dependent on cell area, where current GaAs of 1-mm(2) indoor photovoltaic cells demonstrates power conversion efficiency of approximately 19% at 580 lx of white LED illumination. Reductions in both bulk and perimeter sidewall recombination are required to increase maximum efficiency (while maintaining small cell area near 1 mm(2)) to approach the theoretical power conversion efficiency of 40% for GaAs cells under typical indoor lighting conditions.

  9. Energy Harvesting for GaAs Photovoltaics Under Low-Flux Indoor Lighting Conditions

    PubMed Central

    Teran, Alan S.; Moon, Eunseong; Lim, Wootaek; Kim, Gyouho; Lee, Inhee; Blaauw, David; Phillips, Jamie D.

    2016-01-01

    GaAs photovoltaics are promising candidates for indoor energy harvesting to power small-scale (≈1 mm2) electronics. This application has stringent requirements on dark current, recombination, and shunt leakage paths due to low-light conditions and small device dimensions. The power conversion efficiency and the limiting mechanisms in GaAs photovoltaic cells under indoor lighting conditions are studied experimentally. Voltage is limited by generation–recombination dark current attributed to perimeter sidewall surface recombination based on the measurements of variable cell area. Bulk and perimeter recombination coefficients of 1.464 pA/mm2 and 0.2816 pA/mm, respectively, were extracted from dark current measurements. Resulting power conversion efficiency is strongly dependent on cell area, where current GaAs of 1-mm2 indoor photovoltaic cells demonstrates power conversion efficiency of approximately 19% at 580 lx of white LED illumination. Reductions in both bulk and perimeter sidewall recombination are required to increase maximum efficiency (while maintaining small cell area near 1 mm2) to approach the theoretical power conversion efficiency of 40% for GaAs cells under typical indoor lighting conditions. PMID:28133394

  10. Effects of light condition after simulated acid snow stress on leaves of winter wheat.

    PubMed

    Inada, Hidetoshi; Fujikawa, Seizo; Saito, Hideyuki; Arakawa, Keita

    2007-01-01

    Winter plants regrow after freeze-thawing in acidic meltwater from the acid-snow layer in early winter or early spring. In this study, the responses of cold-acclimated wheat seedlings to different light conditions during the regrowth period after simulated acid snow (SAS) stress were investigated. After freeze-thawing in sulfuric acid (SAS stress) of pH 2.0, dry weight and the maximal quantum yield of photosystem II (PSII) decreased more in mature leaves than in young leaves. In a subsequent regrowth period under light condition, dry weight, relative water content, and the maximal quantum yield of PSII were severely affected in mature leaves but were only slightly affected in SAS (pH 2.0)-stressed young leaves. The levels of membrane lipid peroxidation and hydrogen peroxide in mature leaves of SAS (pH 2.0)-stressed seedlings were significantly higher than those in young leaves during the regrowth period under light condition. The superoxide dismutase activity in young leaves was higher than that in mature leaves during the regrowth period. These results indicate that mature leaves of seedlings during the snow melt season are more sensitive than young leaves to photooxidative stress because of their low acid snow stress tolerance and low capacity for the detoxification of superoxide.

  11. Multilayer surface albedo for face recognition with reference images in bad lighting conditions.

    PubMed

    Lai, Zhao-Rong; Dai, Dao-Qing; Ren, Chuan-Xian; Huang, Ke-Kun

    2014-11-01

    In this paper, we propose a multilayer surface albedo (MLSA) model to tackle face recognition in bad lighting conditions, especially with reference images in bad lighting conditions. Some previous researches conclude that illumination variations mainly lie in the large-scale features of an image and extract small-scale features in the surface albedo (or surface texture). However, this surface albedo is not robust enough, which still contains some detrimental sharp features. To improve robustness of the surface albedo, MLSA further decomposes it as a linear sum of several detailed layers, to separate and represent features of different scales in a more specific way. Then, the layers are adjusted by separate weights, which are global parameters and selected for only once. A criterion function is developed to select these layer weights with an independent training set. Despite controlled illumination variations, MLSA is also effective to uncontrolled illumination variations, even mixed with other complicated variations (expression, pose, occlusion, and so on). Extensive experiments on four benchmark data sets show that MLSA has good receiver operating characteristic curve and statistical discriminating capability. The refined albedo improves recognition performance, especially with reference images in bad lighting conditions.

  12. Performance and trends of high power light emitting diodes

    NASA Astrophysics Data System (ADS)

    Bierhuizen, Serge; Krames, Michael; Harbers, Gerard; Weijers, Gon

    2007-09-01

    We will discuss the performance, progress and trend of High Power Light Emitting Diodes (HP-LEDs), suitable for high luminance applications like micro-display projection, car headlamps, spot lamps, theatre lamps, etc. Key drivers for the high luminance applications are LED parameters such as internal quantum efficiency, extraction efficiency, drive current, operating temperature and optical coupling efficiency, which are important for most applications as they also enable higher lumen/$ ratios. Historical progress, prospects for improving these parameters and potential optical luminance enhancement methods to meet the demands for the various illumination applications are presented.

  13. 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.

  14. Light extinction method on high-pressure diesel injection

    SciTech Connect

    Su, T.F.; El-Beshbeeshy, M.S.; Corradini, M.L.; Farrell, P.V.

    1995-12-31

    A two dimensional optical diagnostic technique based on light extinction was improved and demonstrated in an investigation of diesel spray characteristics at high injection pressures. Traditional light extinction methods require the spray image to be perpendicular to the light path. In the improved light extinction scheme, a tilted spray image which has an angle with the light path is still capable of being processed. This technique utilizes high speed photography and digital image analysis to obtain qualitative and quantitative information of the spray characteristics. The injection system used was an electronically controlled common rail unit injector system with injection pressures up to 100 MPa. The nozzle of the injector was a mini-sac type with six holes on the nozzle tip. Two different injection angle nozzles, 125{degree} and 140{degree}, producing an in-plane tilted spray and an out of plane tilted spray were investigated. The experiments were conducted on a constant volume spray chamber with the injector mounted tilted at an angle of 62.5{degree}. Only one spray plume was viewed, and other sprays were free to inject to the chamber. The spray chamber was pressurized with argon and air under room temperature to match the combustion chamber density at the start of the injection. The experimental results show that the difference in the spray tip penetration length, spray angle, and overall average Sauter mean diameter is small between the in-plane tilted spray and the out of plane tilted spray. The results also show that in-plane tilted spray has a slightly larger axial cross-section average Sauter mean diameter than the out of plane tilted spray.

  15. Season-dependent and independent responses of Mediterranean scrub to light conditions.

    PubMed

    Zunzunegui, María; Díaz-Barradas, Mari Cruz; Jáuregui, Juan; Rodríguez, Herminia; Álvarez-Cansino, Leonor

    2016-05-01

    Semi-arid plant species cope with excess of solar radiation with morphological and physiological adaptations that assure their survival when other abiotic stressors interact. At the leaf level, sun and shade plants may differ in the set of traits that regulate environmental stressors. Here, we evaluated if leaf-level physiological seasonal response of Mediterranean scrub species (Myrtus communis, Halimium halimifolium, Rosmarinus officinalis, and Cistus salvifolius) depended on light availability conditions. We aimed to determine which of these responses prevailed independently of the marked seasonality of Mediterranean climate, to define a leaf-level strategy in the scrub community. Thirty six leaf response variables - involving gas exchange, water status, photosystem II photochemical efficiency, photosynthetic pigments and leaf structure - were seasonally measured in sun exposed and shaded plants under field conditions. Physiological responses showed a common pattern throughout the year, in spite of the marked seasonality of the Mediterranean climate and of species-specific differences in the response to light intensity. Variables related to light use, CO2 assimilation, leaf pigment content, and LMA (leaf mass area) presented differences that were consistent throughout the year, although autumn was the season with greater contrast between sun and shade plants. Our data suggest that in Mediterranean scrub shade plants the lutein pool could have an important role in the photoprotection of the photosynthetic tissues. There was a negative linear correlation between the ratio lutein/total chlorophylls and the majority of leaf level variables. The combined effect of abiotic stress factors (light and drought or light and cold) was variable-specific, in some cases enhancing differences between sun and shade plants, while in others leading to unified strategies in all scrub species.

  16. Morning sleep inertia in alertness and performance: effect of cognitive domain and white light conditions.

    PubMed

    Santhi, Nayantara; Groeger, John A; Archer, Simon N; Gimenez, Marina; Schlangen, Luc J M; Dijk, Derk-Jan

    2013-01-01

    The transition from sleep to wakefulness entails a temporary period of reduced alertness and impaired performance known as sleep inertia. The extent to which its severity varies with task and cognitive processes remains unclear. We examined sleep inertia in alertness, attention, working memory and cognitive throughput with the Karolinska Sleepiness Scale (KSS), the Psychomotor Vigilance Task (PVT), n-back and add tasks, respectively. The tasks were administered 2 hours before bedtime and at regular intervals for four hours, starting immediately after awakening in the morning, in eleven participants, in a four-way cross-over laboratory design. We also investigated whether exposure to Blue-Enhanced or Bright Blue-Enhanced white light would reduce sleep inertia. Alertness and all cognitive processes were impaired immediately upon awakening (p<0.01). However, alertness and sustained attention were more affected than cognitive throughput and working memory. Moreover, speed was more affected than accuracy of responses. The light conditions had no differential effect on performance except in the 3-back task (p<0.01), where response times (RT) at the end of four hours in the two Blue-Enhanced white light conditions were faster (200 ms) than at wake time. We conclude that the effect of sleep inertia varies with cognitive domain and that it's spectral/intensity response to light is different from that of sleepiness. That is, just increasing blue-wavelength in light may not be sufficient to reduce sleep inertia. These findings have implications for critical professions like medicine, law-enforcement etc., in which, personnel routinely wake up from night-time sleep to respond to emergency situations.

  17. Morning Sleep Inertia in Alertness and Performance: Effect of Cognitive Domain and White Light Conditions

    PubMed Central

    Santhi, Nayantara; Groeger, John A.; Archer, Simon N.; Gimenez, Marina; Schlangen, Luc J. M.; Dijk, Derk-Jan

    2013-01-01

    The transition from sleep to wakefulness entails a temporary period of reduced alertness and impaired performance known as sleep inertia. The extent to which its severity varies with task and cognitive processes remains unclear. We examined sleep inertia in alertness, attention, working memory and cognitive throughput with the Karolinska Sleepiness Scale (KSS), the Psychomotor Vigilance Task (PVT), n-back and add tasks, respectively. The tasks were administered 2 hours before bedtime and at regular intervals for four hours, starting immediately after awakening in the morning, in eleven participants, in a four-way cross-over laboratory design. We also investigated whether exposure to Blue-Enhanced or Bright Blue-Enhanced white light would reduce sleep inertia. Alertness and all cognitive processes were impaired immediately upon awakening (p<0.01). However, alertness and sustained attention were more affected than cognitive throughput and working memory. Moreover, speed was more affected than accuracy of responses. The light conditions had no differential effect on performance except in the 3-back task (p<0.01), where response times (RT) at the end of four hours in the two Blue-Enhanced white light conditions were faster (200 ms) than at wake time. We conclude that the effect of sleep inertia varies with cognitive domain and that it’s spectral/intensity response to light is different from that of sleepiness. That is, just increasing blue-wavelength in light may not be sufficient to reduce sleep inertia. These findings have implications for critical professions like medicine, law-enforcement etc., in which, personnel routinely wake up from night-time sleep to respond to emergency situations. PMID:24260280

  18. A high dynamic range structured light means for the 3D measurement of specular surface

    NASA Astrophysics Data System (ADS)

    Song, Zhan; Jiang, Hualie; Lin, Haibo; Tang, Suming

    2017-08-01

    This paper presents a novel structured light approach for the 3D reconstruction of specular surface. The binary shifting strip is adopted as structured light pattern instead of conventional sinusoidal pattern. Based on the framework of conventional High Dynamic Range (HDR) imaging technique, an efficient means is first introduced to estimate the camera response function. And then, dynamic range of the generated radiance map is compressed in the gradient domain by introducing an attenuation function. Subject to the change of lighting conditions caused by projecting different structured light patterns, the structure light image with middle exposure level is selected as the reference image and used for the slight adjustment of the primary fused image. Finally, the regenerated structured light images with well exposing condition are used for 3D reconstruction of the specular surface. To evaluate performance of the method, some stainless stamping parts with strong reflectivity are used for the experiments. And the results showed that, different specular targets with various shapes can be precisely reconstructed by the proposed method.

  19. Influence of iron precipitated condition and light intensity on microalgae activated sludge based wastewater remediation.

    PubMed

    Anbalagan, Anbarasan; Schwede, Sebastian; Lindberg, Carl-Fredrik; Nehrenheim, Emma

    2017-02-01

    The indigenous microalgae-activated sludge (MAAS) process during remediation of municipal wastewater was investigated by studying the influence of iron flocculation step and light intensity. In addition, availability of total phosphorous (P) and photosynthetic activity was examined in fed-batch and batch mode under northern climatic conditions and limited lighting. This was followed by a semi-continuous operation with 4 d of hydraulic retention time and mean cell residence time of 6.75 d in a photo-bioreactor (PBR) with varying P availability. The fed-batch condition showed that P concentrations of 3-4 mg L(-1) were effective for photosynthetic chl. a development in iron flocculated conditions. In the PBR, the oxygen evolution rate increased with increase in the concentration of MAAS (from 258 to 573 mg TSS L(-1)) at higher surface photosynthetic active radiation (250 and 500 μmol m(-2) s(-1)). Additionally, the rate approached a saturation phase at low MAAS (110 mg L(-1)) with higher light intensities. Semi-continuous operation with luxury P uptake and effective P condition showed stable average total nitrogen removal of 88 and 92% respectively, with residual concentrations of 3.77 and 2.21 mg L(-1). The corresponding average P removal was 68 and 59% with residual concentrations of 2.32 and 1.75 mg L(-1). The semi-continuous operation produced a rapidly settleable MAAS under iron flocculated condition with a settling velocity of 92-106 m h(-1) and sludge volume index of 31-43 ml g(-1) in the studied cases.

  20. High light transmission through thin absorptive corrugated films.

    PubMed

    Dmitruk, Nicolas L; Korovin, Alexander V

    2008-05-01

    The enhancement of light transmittance through periodically relief thin absorptive film at surface plasmon polariton excitation conditions, as a function of relief interrelation, was considered theoretically. Our calculation of transmittance-reflectance through periodically relief thin absorptive film was performed in the framework of differential formalism. There are two basic relief interrelation forms, namely, correlated and anticorrelated ones. The obtained spectral and angular dependencies demonstrate an essential increase of surface plasmon polariton peaks in the case of anticorrelated corrugation of film in comparison with the correlated ones.

  1. High-speed OCT light sources and systems [Invited

    PubMed Central

    Klein, Thomas; Huber, Robert

    2017-01-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems. PMID:28270988

  2. Interactions between lighting and space conditioning energy use in U.S. commercial buildings

    SciTech Connect

    Sezgen, O.; Koomey, J.G.

    1998-04-01

    Reductions in lighting energy have secondary effects on cooling and heating energy consumption. In general, lighting energy reductions increase heating and decrease cooling requirements of a building. The net change in a building`s annual energy requirements, however, is difficult to quantify and depends on the building characteristics, operating conditions, and climate. This paper characterizes the effects of lighting/HVAC interactions on the annual heating/cooling requirements of prototypical US commercial buildings through computer simulations using the DOE-2.1E building energy analysis program. Twelve building types of two vintages and five climates are chosen to represent the US commercial building stock. For each combination of building type, vintage, and climate, a prototypical building is simulated with varying lighting power densities, and the resultant changes in heating and cooling loads are recorded. These loads are used together with market information on the saturation of the different HVAC equipment in the commercial buildings to determine the changes i energy use and expenditures for heating and cooling. Results are presented by building type for the US as a whole. Therefore, the data presented in this paper can be utilized to assess the secondary effects of lighting-related federal policies with widespread impacts, like minimum efficiency standards. Generally, in warm climates the interactions will induce monetary savings and in cold climates the interactions will induce monetary penalties. For the commercial building stock in the US, a reduction in lighting energy that is well distributed geographically will induce neither significant savings nor significant penalties from associated changes in HVAC primary energy and energy expenditures.

  3. HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING

    SciTech Connect

    Dr. Paul T. Fini; Prof. Shuji Nakamura

    2002-09-01

    In this annual report we summarize the progress obtained in the first year with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

  4. HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING

    SciTech Connect

    Dr. Paul T. Fini; Prof. Shuji Nakamura

    2002-04-30

    In this semiannual report we summarize the progress obtained in the first six months with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

  5. The effect of lighting conditions on caries interpretation with a laptop computer in a clinical setting.

    PubMed

    Kutcher, Mark J; Kalathingal, Sajitha; Ludlow, John B; Abreu, Murillo; Platin, Enrique

    2006-10-01

    To test the null hypothesis of no difference in caries detection in dim, bright, and hooded environments for laptop viewing of intraoral radiographs. Extracted posterior teeth were imaged with posterior bite wing geometry by using storage phosphor plates. Images were displayed on a laptop computer placed in 3 lighting environments. Six dental students and 6 faculty observers scored the caries status of proximal surfaces. Responses were compared to histologic ground truth by using receiver operating characteristic (ROC) analysis and other measures of accuracy. Performance was also compared to photometer-measured light levels and time spent in observation. ROC A(Z) was significantly higher for faculty using hooded displays (0.87) than in a bright clinical environment (0.79; P = .04). Student performance was highly variable and not significantly different in any of the lighting environments. The ability to detect caries by experienced clinicians may be improved by hooding laptop displays in bright clinical environments.

  6. Successful "First Light" for VLT High-Resolution Spectrograph

    NASA Astrophysics Data System (ADS)

    1999-10-01

    with UVES at KUEYEN was of SN 1987A , the famous supernova that exploded in the Large Magellanic Cloud (LMC) in February 1987, and the brightest supernova of the last 400 years. ESO PR Photo 37a/99 ESO PR Photo 37a/99 [Preview - JPEG: 400 x 455 pix - 87k] [Normal - JPEG: 645 x 733 pix - 166k] Caption to ESO PR Photo 37a/99 : This is a direct image of SN1987A, flanked by two nearby stars. The distance between these two is 4.5 arcsec. The slit (2.0 arcsec wide) through which the echelle spectrum shown in PR Photo 37b/99 was obtained, is outlined. This reproduction is from a 2-min exposure through a R(ed) filter with the FORS1 multi-mode instrument at VLT ANTU, obtained in 0.55 arcsec seeing on September 20, 1998. North is up and East is left. ESO PR Photo 37b/99 ESO PR Photo 37b/99 [Preview - JPEG: 400 x 459 pix - 130k] [Normal - JPEG: 800 x 917 pix - 470k] [High-Res - JPEG: 3000 x 3439 pix - 6.5M] Caption to ESO PR Photo 37b/99 : This shows the raw image, as read from the CCD, with the recorded echelle spectrum of SN1987A. With this technique, the supernova spectrum is divided into many individual parts ( spectral orders , each of which appears as a narrow horizontal line) that together cover the wavelength interval from 479 to 682 nm (from the bottom to the top), i.e. from blue to red light. Many bright emission lines from different elements are visible, e.g. the strong H-alpha line from hydrogen near the centre of the fourth order from the top. Emission lines from the terrestrial atmosphere are seen as vertical bright lines that cover the full width of the individual horizontal bands. Since this exposure was done with the nearly Full Moon above the horizon, an underlying, faint absorption-line spectrum of reflected sunlight is also visible. The exposure time was 30 min and the seeing conditions were excellent (0.5 arcsec). ESO PR Photo 37c/99 ESO PR Photo 37c/99 [Preview - JPEG: 400 x 355 pix - 156k] [Normal - JPEG: 800 x 709 pix - 498k] [High-Res - JPEG: 1074 x 952

  7. The effects of lighting conditions on responses of cells selective for face views in the macaque temporal cortex.

    PubMed

    Hietanen, J K; Perrett, D I; Oram, M W; Benson, P J; Dittrich, W H

    1992-01-01

    Neural mechanisms underlying recognition of objects must overcome the changes in an object's appearance caused by inconsistent viewing conditions, particularly those that occur with changes in lighting. In humans, lesions to the posterior visual association cortex can impair the ability to recognize objects and faces across different lighting conditions. Inferotemporal lesions in monkey have been shown to produce a similar difficulty in object matching tasks. Here we report on the extent to which cell responses selective for the face and other views of the head in monkey temporal cortex tolerate changes in lighting. For each cell studied the (preferred) head view eliciting maximal response was first established under normal lighting. Cells were then tested with the preferred head view lit from different directions (i.e. front, above, below or from the side). Responses of some cells failed to show complete generalization across all lighting conditions but together as a "population" they responded equally strongly under all four lighting conditions. Further tests on sub-groups of cells revealed that stimulus selectivity was maintained despite unusual lighting. The cells discriminated between head and control stimuli and between different views of the head independent of the lighting direction. The results indicate that constancy of recognition across different lighting conditions is apparent in the responses of single cells in the temporal cortex. Lighting constancy appears to be established by matching the retinal image to view-specific descriptions of objects (i.e. neurons which compute object structure from a limited range of perspective views).

  8. Effects of lighting and air-conditioning systems on growth weight and functional composition of frill-lettuce produced in plant factory

    NASA Astrophysics Data System (ADS)

    Yoshida, Atsumasa; Okamura, Nobuya; Furukawa, Hajime; Myojin, Chiho; Moriuchi, Koji; Kinoshita, Shinichi

    2017-06-01

    The aim of the present study was to develop optimal air-conditioning systems for plant factories. To verify the effect of particular air-conditioning and lighting systems, cultivation experiments were performed with frill-lettuce for two weeks. In the present study, the relationship between the cultivation condition, the yield (i.e., increase in edible portion weight), and the functional components were discussed. Based on the measured data, increased photosynthetic photon flux density increased antioxidative activity and edible portion weight, possibly because high light intensities are stressful for frill lettuce. Antioxidative activity also increased under conditions of low CO2 concentration, weak and strong winds, and high air temperature because these conditions became stresses for the plants. However, a decrease in edible portion weight was observed under these conditions, implying there is a negative correlation between antioxidative activity and edible portion weight.

  9. Retinal Pre-Conditioning by CD59a Knockout Protects against Light-Induced Photoreceptor Degeneration

    PubMed Central

    Wilson, Brooks; Zhao, Liangliang; Bhuyan, Rupak; Bandyopadhyay, Mausumi; Lyubarsky, Arkady; Yu, Chen; Li, Yafeng; Kanu, Levi; Miwa, Takashi; Song, Wen-Chao; Finnemann, Silvia C.; Rohrer, Bärbel; Dunaief, Joshua L.

    2016-01-01

    Complement dysregulation plays a key role in the pathogenesis of age-related macular degeneration (AMD), but the specific mechanisms are incompletely understood. Complement also potentiates retinal degeneration in the murine light damage model. To test the retinal function of CD59a, a complement inhibitor, CD59a knockout (KO) mice were used for light damage (LD) experiments. Retinal degeneration and function were compared in WT versus KO mice following light damage. Gene expression changes, endoplasmic reticulum (ER) stress, and glial cell activation were also compared. At baseline, the ERG responses and rhodopsin levels were lower in CD59aKO compared to wild-type (WT) mice. Following LD, the ERG responses were better preserved in CD59aKO compared to WT mice. Correspondingly, the number of photoreceptors was higher in CD59aKO retinas than WT controls after LD. Under normal light conditions, CD59aKO mice had higher levels than WT for GFAP immunostaining in Müller cells, mRNA and protein levels of two ER-stress markers, and neurotrophic factors. The reduction in photon capture, together with the neurotrophic factor upregulation, may explain the structural and functional protection against LD in the CD59aKO. PMID:27893831

  10. Metabolomic Responses of Arabidopsis Suspension Cells to Bicarbonate under Light and Dark Conditions

    PubMed Central

    Misra, Biswapriya B.; Yin, Zepeng; Geng, Sisi; de Armas, Evaldo; Chen, Sixue

    2016-01-01

    Global CO2 level presently recorded at 400 ppm is expected to reach 550 ppm in 2050, an increment likely to impact plant growth and productivity. Using targeted LC-MS and GC-MS platforms we quantified 229 and 29 metabolites, respectively in a time-course study to reveal short-term responses to different concentrations (1, 3, and 10 mM) of bicarbonate (HCO3−) under light and dark conditions. Results indicate that HCO3− treatment responsive metabolomic changes depend on the HCO3− concentration, time of treatment, and light/dark. Interestingly, 3 mM HCO3− concentration treatment induced more significantly changed metabolites than either lower or higher concentrations used. Flavonoid biosynthesis and glutathione metabolism were common to both light and dark-mediated responses in addition to showing concentration-dependent changes. Our metabolomics results provide insights into short-term plant cellular responses to elevated HCO3− concentrations as a result of ambient increases in CO2 under light and dark. PMID:27762345

  11. Metabolomic Responses of Arabidopsis Suspension Cells to Bicarbonate under Light and Dark Conditions.

    PubMed

    Misra, Biswapriya B; Yin, Zepeng; Geng, Sisi; de Armas, Evaldo; Chen, Sixue

    2016-10-20

    Global CO2 level presently recorded at 400 ppm is expected to reach 550 ppm in 2050, an increment likely to impact plant growth and productivity. Using targeted LC-MS and GC-MS platforms we quantified 229 and 29 metabolites, respectively in a time-course study to reveal short-term responses to different concentrations (1, 3, and 10 mM) of bicarbonate (HCO3(-)) under light and dark conditions. Results indicate that HCO3(-) treatment responsive metabolomic changes depend on the HCO3(-) concentration, time of treatment, and light/dark. Interestingly, 3 mM HCO3(-) concentration treatment induced more significantly changed metabolites than either lower or higher concentrations used. Flavonoid biosynthesis and glutathione metabolism were common to both light and dark-mediated responses in addition to showing concentration-dependent changes. Our metabolomics results provide insights into short-term plant cellular responses to elevated HCO3(-) concentrations as a result of ambient increases in CO2 under light and dark.

  12. The effect of ambient light condition on road traffic collisions involving pedestrians on pedestrian crossings.

    PubMed

    Uttley, Jim; Fotios, Steve

    2017-11-01

    Previous research suggests darkness increases the risk of a collision involving a pedestrian and the severity of any injury suffered. Pedestrian crossings are intended to make it safer to cross the road, but it is not clear whether they are effective at doing this after-dark, compared with during daylight. Biannual clock changes resulting from transitions to and from daylight saving time were used to compare RTCs in the UK during daylight and darkness but at the same time of day, thus controlling for potential influences on RTC numbers not related to the ambient light condition. Odds ratios and regression discontinuity analysis suggested there was a significantly greater risk of a pedestrian RTC at a crossing after-dark than during daylight. Results also suggested the risk of an RTC after-dark was greater at a pedestrian crossing than at a location at least 50m away from a crossing. Whilst these results show the increased danger to pedestrians using a designated crossing after-dark, this increased risk is not due to a lack of lighting at these locations as 98% of RTCs at pedestrian crossings after-dark were lit by road lighting. This raises questions about the adequacy and effectiveness of the lighting used at pedestrian crossings. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  13. Retinal Pre-Conditioning by CD59a Knockout Protects against Light-Induced Photoreceptor Degeneration.

    PubMed

    Song, Delu; Wilson, Brooks; Zhao, Liangliang; Bhuyan, Rupak; Bandyopadhyay, Mausumi; Lyubarsky, Arkady; Yu, Chen; Li, Yafeng; Kanu, Levi; Miwa, Takashi; Song, Wen-Chao; Finnemann, Silvia C; Rohrer, Bärbel; Dunaief, Joshua L

    2016-01-01

    Complement dysregulation plays a key role in the pathogenesis of age-related macular degeneration (AMD), but the specific mechanisms are incompletely understood. Complement also potentiates retinal degeneration in the murine light damage model. To test the retinal function of CD59a, a complement inhibitor, CD59a knockout (KO) mice were used for light damage (LD) experiments. Retinal degeneration and function were compared in WT versus KO mice following light damage. Gene expression changes, endoplasmic reticulum (ER) stress, and glial cell activation were also compared. At baseline, the ERG responses and rhodopsin levels were lower in CD59aKO compared to wild-type (WT) mice. Following LD, the ERG responses were better preserved in CD59aKO compared to WT mice. Correspondingly, the number of photoreceptors was higher in CD59aKO retinas than WT controls after LD. Under normal light conditions, CD59aKO mice had higher levels than WT for GFAP immunostaining in Müller cells, mRNA and protein levels of two ER-stress markers, and neurotrophic factors. The reduction in photon capture, together with the neurotrophic factor upregulation, may explain the structural and functional protection against LD in the CD59aKO.

  14. Distribution of light in the human retina under natural viewing conditions

    NASA Astrophysics Data System (ADS)

    Gibert, Jorge C.

    Age-related macular degeneration (AMD) is the leading cause of blindness inAmerica. The fact that AMD wreaks most of the damage in the center of the retina raises the question of whether light, integrated over long periods, is more concentrated in the macula. A method, based on eye-tracking, was developed to measure the distribution of light in the retina under natural viewing conditions. The hypothesis was that integrated over time, retinal illumination peaked in the macula. Additionally a possible relationship between age and retinal illumination was investigated. The eye tracker superimposed the subject's gaze position on a video recorded by a scene camera. Five informed subjects were employed in feasibility tests, and 58 naive subjects participated in 5 phases. In phase 1 the subjects viewed a gray-scale image. In phase 2, they observed a sequence of photographic images. In phase 3 they viewed a video. In phase 4, they worked on a computer; in phase 5, the subjects walked around freely. The informed subjects were instructed to gaze at bright objects in the field of view and then at dark objects. Naive subjects were allowed to gaze freely for all phases. Using the subject's gaze coordinates, and the video provided by the scene camera, the cumulative light distribution on the retina was calculated for ˜15° around the fovea. As expected for control subjects, cumulative retinal light distributions peaked and dipped in the fovea when they gazed at bright or dark objects respectively. The light distribution maps obtained from the naive subjects presented a tendency to peak in the macula for phases 1, 2, and 3, a consistent tendency in phase 4 and a variable tendency in phase 5. The feasibility of using an eye-tracker system to measure the distribution of light in the retina was demonstrated, thus helping to understand the role played by light exposure in the etiology of AMD. Results showed that a tendency for light to peak in the macula is a characteristic of some

  15. Differential gene expression in Ulva prolifera under low light and low temperature conditions.

    PubMed

    Li, Youxun; Zhang, Xiaowen; Xu, Dong; Zhuang, Zhimeng; Ye, Naihao

    2012-08-01

    The past several years witnessed the increasing global interest in the marine green macroalga Ulva prolifera as it is a key causative species of the massive green tides successively occurring in the Yellow Sea. Accurate localization of the 'seed' source is one of the principal scientific concerns to be solved before it is possible to manage these algal blooms. It has been suggested that somatic cells of Ulva prolifera which settled in cold benthic sediments might serve as one of the major propagule banks. To identify the molecular mechanisms underlying this hypothesis, PCR-based suppression subtractive hybridization was employed to analyze the differential gene expression of Ulva prolifera under low light and low temperature conditions (matching the cold benthic sediments conditions, 6 °C, 30 μmol photons m(-2) s(-1)). 137 ESTs representing 88 unigenes (80 singletons and 8 contigs) were detected as being over-expressed, whereas 109 unigenes (96 singletons and 13 contigs) in 130 ESTs were found to be down-regulated in this study. BLASTX analysis revealed that 65 % of the over-expressed and 59 % of the down-regulated genes did not belong to any documented functionally annotated or hypothetical proteins in the public database. However, analysis of the functional defined sequences displayed (1) an obvious sign of senescence, (2) enhancements of the photosynthesis system and the pentose phosphate pathway, (3) slow-down of activities in a wide range of processes including the DNA replication, the transcription, the translation, the glycolysis, the citrate cycle and the pyruvate metabolism in Ulva prolifera cells under low light and low temperature conditions. This work disclosed some basic information of the molecular mechanisms of Ulva prolifera cells under low light and low temperature conditions and provides useful clues for future studies on the "seed" source of the massive green tides.

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

    SciTech Connect

    Arto V. Nurmikko; Jung Han

    2007-03-31

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

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

    SciTech Connect

    Arto V. Nurmikko; Jung Han

    2005-09-30

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the second 12 month contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  18. High fluence light emitting diode-generated red light modulates characteristics associated with skin fibrosis.

    PubMed

    Mamalis, Andrew; Koo, Eugene; Garcha, Manveer; Murphy, William J; Isseroff, R Rivkah; Jagdeo, Jared

    2016-12-01

    Skin fibrosis, often referred to as skin scarring, is a significant international health problem with limited treatment options. The hallmarks of skin fibrosis are increased fibroblast proliferation, collagen production, and migration speed. Recently published clinical observations indicate that visible red light may improve skin fibrosis. In this study we hypothesize that high-fluence light-emitting diode-generated red light (HF-LED-RL) modulates the key cellular features of skin fibrosis by decreasing cellular proliferation, collagen production, and migration speed of human skin fibroblasts. Herein, we demonstrate that HF-LED-RL increases reactive oxygen species (ROS) generation for up to 4 hours, inhibits fibroblast proliferation without increasing apoptosis, inhibits collagen production, and inhibits migration speed through modulation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. We demonstrate that HF-LED-RL is capable of inhibiting the unifying cellular processes involved in skin fibrosis including fibroblast proliferation, collagen production, and migration speed. These findings suggest that HF-LED-RL may represent a new approach to treat skin fibrosis. LED advantages include low cost, portability, and ease of use. Further characterizing the photobiomodulatory effects of HF-LED-RL on fibroblasts and investigating the anti-fibrotic effects of HF-LED-RL in human subjects may provide new insight into the utility of this therapeutic approach for skin fibrosis.

  19. High light-induced hydrogen peroxide production in Chlamydomonas reinhardtii is increased by high CO2 availability.

    PubMed

    Roach, Thomas; Na, Chae Sun; Krieger-Liszkay, Anja

    2015-03-01

    The production of reactive oxygen species (ROS) is an unavoidable part of photosynthesis. Stress that accompanies high light levels and low CO2 availability putatively includes enhanced ROS production in the so-called Mehler reaction. Such conditions are thought to encourage O2 to become an electron acceptor at photosystem I, producing the ROS superoxide anion radical (O2·-) and hydrogen peroxide (H2 O2 ). In contrast, here it is shown in Chlamydomonas reinhardtii that CO2 depletion under high light levels lowered cellular H2 O2 production, and that elevated CO2 levels increased H2 O2 production. Using various photosynthetic and mitochondrial mutants of C. reinhardtii, the chloroplast was identified as the main source of elevated H2 O2 production under high CO2 availability. High light levels under low CO2 availability induced photoprotective mechanisms called non-photochemical quenching, or NPQ, including state transitions (qT) and high energy state quenching (qE). The qE-deficient mutant npq4 produced more H2 O2 than wild-type cells under high light levels, although less so under high CO2 availability, whereas it demonstrated equal or greater enzymatic H2 O2 -degrading capacity. The qT-deficient mutant stt7-9 produced the same H2 O2 as wild-type cells under high CO2 availability. Physiological levels of H2 O2 were able to hinder qT and the induction of state 2, providing an explanation for why under high light levels and high CO2 availability wild-type cells behaved like stt7-9 cells stuck in state 1. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  20. Effect of light and oxygen and adaptation to changing light conditions in a photosynthetic mutant in which the LHII complex of Rhv. sulfidophilum was heterologously expressed in a strain of Rb. capsulatus whose puc operon was deleted.

    PubMed

    Barbieri Md, María del Rosario; Kerber, Norma L; Pucheu, Norma L; Tadros, Monier H; García, Augusto F

    2002-09-01

    In this paper we show the effect of oxygen and light on the expression of the photosynthetic apparatus of a mutant heterologously expressing the puc operon. This mutant was obtained by introducing in trans an expression plasmid, bearing the puc A, B, and C genes of Rhv. sulfidophilum, as well as its own promoter, in an LHII(-) mutant of Rb. capsulatus. The results showed that oxygen and light repressed LHII expression. Even low-light intensities lowered the LHII content to undetectable levels by spectrophotometry or by SDS-PAGE. In high-light grown cells, where the relative ratios of LHI and LHII complexes were significantly diminished, we were able to detect LHII complexes. Under the latter condition, the absorption spectrum showed that some pigment accumulated in the membrane even in the absence of cell division. These pigments were used in a later step to assemble LHII complexes, when the high-light grown cells were transferred to semiaerobiosis in the dark. Transition of high-light grown cells to low-light conditions allowed us to study the adaptability of these heterologous mutant cells. We observed that adaptation never occurred, in part probably owing to energy limitation.

  1. Constant Light Output Ballasting For High Intensity Discharge Lamps

    NASA Astrophysics Data System (ADS)

    Donkin, Adrian

    1988-02-01

    Since the commercial introduction some twenty years ago of HMI* (Hydragyrum-mercury, Medium, Iodide) type lamps, as a source intended primarily for floodlighting applications, their attraction as a cinematographic light source has been apparent due to their largely desirable characteristics. Use in this field has been restricted due to the absolute requirement for an alternating current supply - with a sine wave supply frame rates are limited to a sub-multiple of the supply frequency with the supply frequency phase locked to the camera frame rate. This has effectively barred metal halide HID lighting from use in high speed photography. The general characteristics of metal halide HID lamps are presented alongside a sample of other light sources. An electronic ballast which has been proven to 12000 Watts in the motion picture industry is then described which overcomes the limitations of the conventional magnetic ballast - the square wave output of the electronic ballast theoretically allows the use of any camera frame rate/shutter angle combination. Finally the suitability of luminaires for high speed photography is discussed.

  2. Changes in the photosynthetic apparatus of diatoms in response to low and high light intensities.

    PubMed

    Janssen, M; Bathke, L; Marquardt, J; Krumbein, W E; Rhiel, E

    2001-03-01

    The centric diatom Cyclotella cryptica and two strains of the pennate diatom Phaeodactylum tricornutum were grown under low and high light intensities (300 lux and 3,000 lux) over 4-6 weeks. Growth was monitored by repetitive cell count. The culture media were replaced weekly to avoid morphological and biochemical alterations caused by nutrient depletion. The ultrastructure of the cells was examined by transmission electron microscopy. Alterations in the light-harvesting antenna systems were investigated by Western immunoblotting. Both diatoms reduced the plastid area, i.e. decreased the amount of thylakoid lamellae, under high light intensity. The thylakoids still ran in groups of three with parallel orientation within the chloroplasts. The girdle band lamellae were not affected. The amounts of storage compounds and vacuoles increased. SDS-PAGE of total cell protein followed by Western immunoblotting with antisera directed against subunits of the light-harvesting antenna systems of C. cryptica (cc-antiserum) and the cryptophyte Cryptomonas maculata (cmac-antiserum) revealed that both diatoms reduced the amount of antenna polypeptides under increased light intensity. The cc-antiserum immunodecorated two bands with relative molecular masses (Mr) of 18,000 and 22,000 in C. cryptica. Both decreased under high light conditions to 67.2 +/- 6.1%. Five to seven bands in the Mr range of 14,000-27,000 were recognized in P. tricornutum. They decreased to 83 +/- 5.3%. Furthermore, the immunolabeling pattern for both strains differed under the two light regimes. The cmac-antiserum immunodecorated two polypeptides with Mr of 24,000 and 23,000 in C. cryptica, while both strains of P. tricornutum had five polypeptides in the Mr range of 14,000-24,000 that showed some differences in staining intensities between the two strains and in response to the light intensity applied.

  3. High brightness formamidinium lead bromide perovskite nanocrystal light emitting devices

    PubMed Central

    Perumal, Ajay; Shendre, Sushant; Li, Mingjie; Tay, Yong Kang Eugene; Sharma, Vijay Kumar; Chen, Shi; Wei, Zhanhua; Liu, Qing; Gao, Yuan; Buenconsejo, Pio John S.; Tan, Swee Tiam; Gan, Chee Lip; Xiong, Qihua; Sum, Tze Chien; Demir, Hilmi Volkan

    2016-01-01

    Formamidinium lead halide (FAPbX3) has attracted greater attention and is more prominent recently in photovoltaic devices due to its broad absorption and higher thermal stability in comparison to more popular methylammonium lead halide MAPbX3. Herein, a simple and highly reproducible room temperature synthesis of device grade high quality formamidinium lead bromide CH(NH2)2PbBr3 (FAPbBr3) colloidal nanocrystals (NC) having high photoluminescence quantum efficiency (PLQE) of 55–65% is reported. In addition, we demonstrate high brightness perovskite light emitting device (Pe-LED) with these FAPbBr3 perovskite NC thin film using 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) commonly known as TPBi and 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) as electron transport layers (ETL). The Pe-LED device with B3PYMPM as ETL has bright electroluminescence of up to 2714 cd/m2, while the Pe-LED device with TPBi as ETL has higher peak luminous efficiency of 6.4 cd/A and peak luminous power efficiency of 5.7 lm/W. To our knowledge this is the first report on high brightness light emitting device based on CH(NH2)2PbBr3 widely known as FAPbBr3 nanocrystals in literature. PMID:27827424

  4. High brightness formamidinium lead bromide perovskite nanocrystal light emitting devices

    NASA Astrophysics Data System (ADS)

    Perumal, Ajay; Shendre, Sushant; Li, Mingjie; Tay, Yong Kang Eugene; Sharma, Vijay Kumar; Chen, Shi; Wei, Zhanhua; Liu, Qing; Gao, Yuan; Buenconsejo, Pio John S.; Tan, Swee Tiam; Gan, Chee Lip; Xiong, Qihua; Sum, Tze Chien; Demir, Hilmi Volkan

    2016-11-01

    Formamidinium lead halide (FAPbX3) has attracted greater attention and is more prominent recently in photovoltaic devices due to its broad absorption and higher thermal stability in comparison to more popular methylammonium lead halide MAPbX3. Herein, a simple and highly reproducible room temperature synthesis of device grade high quality formamidinium lead bromide CH(NH2)2PbBr3 (FAPbBr3) colloidal nanocrystals (NC) having high photoluminescence quantum efficiency (PLQE) of 55–65% is reported. In addition, we demonstrate high brightness perovskite light emitting device (Pe-LED) with these FAPbBr3 perovskite NC thin film using 2,2‧,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) commonly known as TPBi and 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) as electron transport layers (ETL). The Pe-LED device with B3PYMPM as ETL has bright electroluminescence of up to 2714 cd/m2, while the Pe-LED device with TPBi as ETL has higher peak luminous efficiency of 6.4 cd/A and peak luminous power efficiency of 5.7 lm/W. To our knowledge this is the first report on high brightness light emitting device based on CH(NH2)2PbBr3 widely known as FAPbBr3 nanocrystals in literature.

  5. High brightness formamidinium lead bromide perovskite nanocrystal light emitting devices.

    PubMed

    Perumal, Ajay; Shendre, Sushant; Li, Mingjie; Tay, Yong Kang Eugene; Sharma, Vijay Kumar; Chen, Shi; Wei, Zhanhua; Liu, Qing; Gao, Yuan; Buenconsejo, Pio John S; Tan, Swee Tiam; Gan, Chee Lip; Xiong, Qihua; Sum, Tze Chien; Demir, Hilmi Volkan

    2016-11-09

    Formamidinium lead halide (FAPbX3) has attracted greater attention and is more prominent recently in photovoltaic devices due to its broad absorption and higher thermal stability in comparison to more popular methylammonium lead halide MAPbX3. Herein, a simple and highly reproducible room temperature synthesis of device grade high quality formamidinium lead bromide CH(NH2)2PbBr3 (FAPbBr3) colloidal nanocrystals (NC) having high photoluminescence quantum efficiency (PLQE) of 55-65% is reported. In addition, we demonstrate high brightness perovskite light emitting device (Pe-LED) with these FAPbBr3 perovskite NC thin film using 2,2',2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) commonly known as TPBi and 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PYMPM) as electron transport layers (ETL). The Pe-LED device with B3PYMPM as ETL has bright electroluminescence of up to 2714 cd/m(2), while the Pe-LED device with TPBi as ETL has higher peak luminous efficiency of 6.4 cd/A and peak luminous power efficiency of 5.7 lm/W. To our knowledge this is the first report on high brightness light emitting device based on CH(NH2)2PbBr3 widely known as FAPbBr3 nanocrystals in literature.

  6. Drivers' eye movements as a function of collision avoidance warning conditions in red light running scenarios.

    PubMed

    Zhang, Yuting; Yan, Xuedong; Li, Xiaomeng; Xue, Qingwan

    2016-11-01

    The intersection collision avoidance warning systems (ICAWSs) have substantial potentials in improving driving performance and reducing the number and severity of intersection collisions, through helping drivers timely detect hazardous conflicting vehicles in precrash scenarios. However, the influences of ICAWS on drivers' visual performance have barely been discussed. This study focuses on exploring the patterns in drivers' eye movements as a function of ICAWS's warning conditions in red light running scenarios based on a driving simulation experiment. Two types of speech warning conditions including warning timings (varied form 2.5s to 5.5s) and directional information (with or without) are examined, and the no-warning condition is the baseline. The results revealed that more subjects would be likely to benefit from the ICWAS under the earlier warning timings. The warning condition of 4.5s ahead of a collision had the best effectiveness in terms of visual performances. Under such a warning timing, drivers had shorter fixation duration and higher frequency of searching for the red light running (RLR) vehicles. Compared to the warning condition without directional information, the directional warning information could capture drivers' attention more efficiently, help driver direct fixations toward the RLR vehicles more quickly and lead to more scanning activities. Compared to female drivers, male drivers had more scanning activities when approaching intersections, detected the RLR vehicles more quickly and were more likely to avoid the RLR collisions. Besides, the experiment results indicated that the female drivers were more inclined to trust the warning information and got more benefits from the RLR-ICAWS in terms of the crash risk reduction rate than male drivers. Finally, the conclusions lead the way toward warning condition design recommendations for improving the effectiveness of the RLR-ICAWSs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Edaphic and light conditions of sympatric plant morphotypes in western Amazonia.

    PubMed

    Roncal, Julissa

    2014-01-01

    Here I present a dataset of edaphic and light conditions associated with the occurrence of sympatric morphotypes of Geonomamacrostachys (Arecaceae/Palmae), a candidate case study from Amazonia hypothesized to have evolved under ecological speciation. Transects were established in three lowland rainforests in Peru, and the abundance of each local morphotype of this species was recorded in a total area of 4.95 hectares. Composite soil samples and hemispherical photographs were taken along the transects were the species occurred to obtain information on soil nutrients, soil texture, and indirect measurements of light availability. The raw and summary tables disclose the characteristics of each study site and habitats within them, which could be useful to soil scientists, ecologists, and conservationists engaged in similar research activities or meta-analyses in Amazonia.

  8. Introduction of correlative light and airSEMTM microscopy imaging for tissue research under ambient conditions

    PubMed Central

    Solomonov, Inna; Talmi-Frank, Dalit; Milstein, Yonat; Addadi, Sefi; Aloshin, Anna; Sagi, Irit

    2014-01-01

    A complete fingerprint of a tissue sample requires a detailed description of its cellular and extracellular components while minimizing artifacts. We introduce the application of a novel scanning electron microscope (airSEMTM) in conjunction with light microscopy for functional analysis of tissue preparations at nanometric resolution (<10 nm) and under ambient conditions. Our metal-staining protocols enable easy and detailed visualization of tissues and their extracellular scaffolds. A multimodality imaging setup, featuring airSEMTM and a light microscope on the same platform, provides a convenient and easy-to-use system for obtaining structural and functional correlative data. The airSEMTM imaging station complements other existing imaging solutions and shows great potential for studies of complex biological systems. PMID:25100357

  9. Edaphic and light conditions of sympatric plant morphotypes in western Amazonia

    PubMed Central

    2014-01-01

    Abstract Here I present a dataset of edaphic and light conditions associated with the occurrence of sympatric morphotypes of Geonoma macrostachys (Arecaceae/Palmae), a candidate case study from Amazonia hypothesized to have evolved under ecological speciation. Transects were established in three lowland rainforests in Peru, and the abundance of each local morphotype of this species was recorded in a total area of 4.95 hectares. Composite soil samples and hemispherical photographs were taken along the transects were the species occurred to obtain information on soil nutrients, soil texture, and indirect measurements of light availability. The raw and summary tables disclose the characteristics of each study site and habitats within them, which could be useful to soil scientists, ecologists, and conservationists engaged in similar research activities or meta-analyses in Amazonia. PMID:24891831

  10. New robust and highly customizable light source management system

    NASA Astrophysics Data System (ADS)

    Minegishi, Yuji; Takahisa, Kenji; Ochiai, Hideyuki; Ohta, Takeshi; Enami, Tatsuo

    2015-03-01

    In semiconductor lithography, light sources play a significant role in the wafer production process as well as impacting the manufacturing cost per wafer. Chip manufacturers going forward will be challenged to develop new ways to become more cost effective than their competitors, and the software tools necessary to compete in this environment must be capable of effectively adapting to the unique needs of each manufacturer. Gigaphoton has developed a new highly customizable software system for managing light sources. It not only offers a simple and intuitive user interface that can be operated using a standard web browser on PCs, tablets, and smartphones, but also a platform for users and third parties to develop unique extensions and optimizations.

  11. Chlamydomonas reinhardtii responding to high light: A role for 2-propenal (acrolein).

    PubMed

    Roach, Thomas; Baur, Theresa; Stöggl, Wolfgang; Krieger-Liszkay, Anja

    2017-03-21

    High light causes photosystem II to generate singlet oxygen ((1) O2 ), a reactive oxygen species (ROS) that can react with membrane lipids, releasing reactive electrophile species (RES), such as acrolein. To investigate how RES may contribute to light stress responses, Chlamydomonas reinhardtii was high light-treated in photoautotrophic and mixotrophic conditions and also in an oxygen-enriched atmosphere to elevate ROS production. The responses were compared to exogenous acrolein. Non-photochemical quenching (NPQ) was higher in photoautotrophic cells, as a consequence of a more de-epoxidized state of the xanthophyll cycle pool and more LHCSR3 protein, showing that photosynthesis was under more pressure than in mixotrophic cells. Photoautotrophic cells had lowered α-tocopherol and β-carotene contents and a higher level of protein carbonylation, indicators of elevated (1) O2 production. Levels of glutathione, glutathione peroxidase (GPX5) and glutathione-S-transferase (GST1), important antioxidants against RES, were also increased in photoautotrophic cells. In parallel to wild-type, the LHCSR3-deficient npq4 mutant was high light-treated, which in photoautotrophic conditions exhibited particular sensitivity under elevated oxygen, the treatment that induced the highest RES levels, including acrolein. The npq4 mutant had more GPX5 and GST1 alongside higher levels of carbonylated protein and a more oxidized glutathione redox state. In wild-type cells glutathione contents doubled after 4 h treatment, either with high light under elevated oxygen or with a non-critical dose (600 ppm) of acrolein. Exogenous acrolein also increased GST1 levels, but not GPX5. Overall, RES-associated oxidative damage and glutathione metabolism are prominently associated with light stress and potentially in signaling responses of C. reinhardtii.

  12. Circadian Oscillation of the Lettuce Transcriptome under Constant Light and Light–Dark Conditions

    PubMed Central

    Higashi, Takanobu; Aoki, Koh; Nagano, Atsushi J.; Honjo, Mie N.; Fukuda, Hirokazu

    2016-01-01

    Although, the circadian clock is a universal biological system in plants and it orchestrates important role of plant production such as photosynthesis, floral induction and growth, there are few such studies on cultivated species. Lettuce is one major cultivated species for both open culture and plant factories and there is little information concerning its circadian clock system. In addition, most of the relevant genes have not been identified. In this study, we detected circadian oscillation in the lettuce transcriptome using time-course RNA sequencing (RNA-Seq) data. Constant light (LL) and light–dark (LD) conditions were used to detect circadian oscillation because the circadian clock has some basic properties: one is self-sustaining oscillation under constant light and another is entrainment to environmental cycles such as light and temperature. In the results, 215 contigs were detected as common oscillating contigs under both LL and LD conditions. The 215 common oscillating contigs included clock gene-like contigs CCA1 (CIRCADIAN CLOCK ASSOCIATED 1)-like, TOC1 (TIMING OF CAB EXPRESSION 1)-like and LHY (LATE ELONGATED HYPOCOTYL)-like, and their expression patterns were similar to those of Arabidopsis. Functional enrichment analysis by GO (gene ontology) Slim and GO Fat showed that the GO terms of response to light stimulus, response to stress, photosynthesis and circadian rhythms were enriched in the 215 common oscillating contigs and these terms were actually regulated by circadian clocks in plants. The 215 common oscillating contigs can be used to evaluate whether the gene expression pattern related to photosynthesis and optical response performs normally in lettuce. PMID:27512400

  13. Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO2 Partial Pressure Conditions

    PubMed Central

    Pierangelini, Mattia; Sinha, Rati; Burford, Michele A.; Neilan, Brett A.

    2015-01-01

    Cylindrospermopsin (CYN) and 7-deoxy-cylindrospermopsin (dCYN) are potent hepatotoxic alkaloids produced by numerous species of cyanobacteria, including the freshwater Cylindrospermopsis raciborskii. C. raciborskii is an invasive cyanobacterium, and the study of how environmental parameters drive CYN production has received significant interest from water managers and health authorities. Light and CO2 affect cell growth and physiology in photoautotrophs, and these are potential regulators of cyanotoxin biosynthesis. In this study, we investigated how light and CO2 affect CYN and dCYN pool size as well as the expression of the key genes, cyrA and cyrK, involved in CYN biosynthesis in a toxic C. raciborskii strain. For cells growing at different light intensities (10 and 100 μmol photons m−2 s−1), we observed that the rate of CYN pool size production (μCYN) was coupled to the cell division rate (μc) during batch culture. This indicated that CYN pool size under our experimental conditions is constant and cell quotas of CYN (QCYN) and dCYN (QdCYN) are fixed. Moreover, a lack of correlation between expression of cyrA and total CYN cell quotas (QCYNs) suggests that the CYN biosynthesis is regulated posttranscriptionally. Under elevated CO2 (1,300 ppm), we observed minor effects on QCYN and no effects on expression of cyrA and cyrK. We conclude that the CYN pool size is constitutive and not affected by light and CO2 conditions. Thus, C. raciborskii bloom toxicity is determined by the absolute abundance of C. raciborskii cells within the water column and the relative abundance of toxic and nontoxic strains. PMID:25724956

  14. Thin Film Packaging Solutions for High Efficiency OLED Lighting Products

    SciTech Connect

    2008-06-30

    The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology was characterized

  15. High voltage ignition of high pressure microwave powered UV light sources

    SciTech Connect

    Frank, J.D.; Cekic, M.; Wood, C.H.

    1997-12-31

    Industrial microwave powered (electrodeless) light sources have been limited to quiescent pressures of {approximately}300 Torr of buffer gas and metal-halide fills. The predominant reason for such restrictions has been the inability to microwave ignite the plasma due to the collisionality of higher pressure fills and/or the electronegativity of halide bulb chemistries. Commercially interesting bulb fills require electric fields for ionization that are often large multiples of the breakdown voltage for air. Many auxiliary ignition methods are evaluated for efficiency and practicality before the choice of a high-voltage system with a retractable external electrode. The scheme utilizes a high voltage pulse power supply and a novel field emission source. Acting together they create localized condition of pressure reduction and high free electron density. This allows the normal microwave fields to drive this small region into avalanche, ignite the bulb, and heat the plasma to its operating point (T{sub e} {approx} 0.5 eV). This process is currently being used in a new generation of lamps, which are using multi-atmospheric excimer laser chemistries and pressure and constituent enhanced metal-halide systems. At the present time, production prototypes produce over 900 W of radiation in a 30 nm band, centered at 308 nm. Similarly, these prototypes when loaded with metal-halide bulb fills produce over 1 kW of radiation in 30 nm wide bands, centered about the wavelength of interest.

  16. Unregulated gaseous exhaust emission from modern ethanol fuelled light duty vehicles in cold ambient condition

    NASA Astrophysics Data System (ADS)

    Clairotte, M.; Adam, T. W.; Zardini, A. A.; Astorga, C.

    2011-12-01

    the first minutes of the cycle, before the light-off of the Three-Way Catalyst (TWC). Less ammonia has been emitted with ethanol fuel, in particular in low ambient condition (E75 versus E5). Ammonia is a harmful compound for human health and vegetation, and is a precursor of secondary aerosol. Even if agricultural activities are the main source of anthropogenic ammonia, the contribution from the transport sector increases significantly during the cold season. Consequently, using high concentrated ethanol as fuel may have a positive impact on ammonia emission in urban area. However, ethanol fuel had a negative impact on formaldehyde and acetaldehyde. The latter together with methane was notably emitted in low ambient temperature, in comparison with gasoline fuel (E5). Moreover, the OFP at -7°C was influenced by the amount of ethanol in gasoline, mainly because of the increase of ozone precursors linked to ethanol (ethylene, acetylene, and acetaldehyde). Even if ozone concentration levels are generally lower during the cold seasons these results show that the issue should be considered globally before promoting the use of high concentrated ethanol fuel in a large scale.

  17. In vivo cytochrome and alternative pathway respiration in leaves of Arabidopsis thaliana plants with altered alternative oxidase under different light conditions.

    PubMed

    Florez-Sarasa, Igor; Flexas, Jaume; Rasmusson, Allan G; Umbach, Ann L; Siedow, James N; Ribas-Carbo, Miquel

    2011-08-01

    The in vivo activity of the alternative pathway (ν(alt)) has been studied using the oxygen isotope fractionation method in leaves of Arabidopsis thaliana modified for the expression of the AtAOX1a gene by anti-sense (AS-12) or overexpression (XX-2). Under non-stressful conditions, ν(alt) was similar in all plant lines regardless of its different alternative pathway capacities (V(alt)). Total leaf respiration (V(t)) and V(alt) were directly related to growth light conditions while electron partitioning between the cytochrome pathway (CP) and alternative pathway (AP) was unchanged by light levels. Interestingly, the AP functioned at full capacity in anti-sense plants under both growth light conditions. The role of the AP in response to a high light stress induced by short-term high light treatment (HLT) was also studied. In wild type and XX-2, both CP and AP rates increased proportionally after HLT while in AS-12, where the AP was unable to increase its rate, the CP accommodated all the increase in respiration. The results obtained under high light stress suggest that flexibility in the response of the mitochondrial electron transport chain is involved in sustaining photosynthetic rates in response to this stress while the saturated AP in AS-12 plants may contribute to the observed increase in photoinhibition. © 2011 Blackwell Publishing Ltd.

  18. Cylindrospermopsin induced changes in growth, toxin production and antioxidant response of Acutodesmus acuminatus and Microcystis aeruginosa under differing light and nitrogen conditions.

    PubMed

    Chia, Mathias Ahii; Cordeiro-Araújo, Micheline Kézia; Lorenzi, Adriana Sturion; Bittencourt-Oliveira, Maria do Carmo

    2017-08-01

    Growing evidence suggests that some bioactive metabolites (e.g. cyanotoxins) produced by cyanobacteria have allelopathic potential, due to their inhibitory or stimulatory effects on competing species. Although a number of studies have shown that the cyanotoxin cylindrospermopsin (CYN) has variable effects on phytoplankton species, the impact of changing physicochemical conditions on its allelopathic potential is yet to be investigated. We investigated the physiological response of Microcystis aeruginosa (Cyanobacteria) and Acutodesmus acuminatus (Chlorophyta) to CYN under varying nitrogen and light conditions. At 24h, higher microcystins content of M. aeruginosa was recorded under limited light in the presence of CYN, while at 120h the lower levels of the toxins were observed in the presence of CYN under optimum light. Total MCs concentration was significantly (p<0.05) lowered by CYN after 120h of exposure under limited and optimum nitrogen conditions. On the other hand, there were no significant (p>0.05) changes in total MCs concentrations after exposure to CYN under high nitrogen conditions. As expected, limited light and limited nitrogen conditions resulted in lower cell density of both species, while CYN only significantly (p<0.05) inhibited the growth of M. aeruginosa. Regardless of the light or nitrogen condition, the presence of CYN increased internal H2O2 content of both species, which resulted in significant (p<0.05) changes in antioxidant enzyme (catalase, peroxidase, superoxide dismutase and glutathione S-transferase) activities. The oxidative stress caused by CYN was higher under limited light and limited nitrogen. These results showed that M. aeruginosa and A. acuminatus have variable response to CYN under changing light and nitrogen conditions, and demonstrate that need to consider changes in physicochemical conditions during ecotoxicological and ecophysiological investigations. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Interactive effects of juvenile defoliation, light conditions, and interspecific competition on growth and ectomycorrhizal colonization of Fagus sylvatica and Pinus sylvestris seedlings.

    PubMed

    Trocha, Lidia K; Weiser, Ewa; Robakowski, Piotr

    2016-01-01

    Seedlings of forest tree species are exposed to a number of abiotic (organ loss or damage, light shortage) and biotic (interspecific competition) stress factors, which may lead to an inhibition of growth and reproduction and, eventually, to plant death. Growth of the host and its mycorrhizal symbiont is often closely linked, and hence, host damage may negatively affect the symbiont. We designed a pot experiment to study the response of light-demanding Pinus sylvestris and shade-tolerant Fagus sylvatica seedlings to a set of abiotic and biotic stresses and subsequent effects on ectomycorrhizal (ECM) root tip colonization, seedling biomass, and leaf nitrogen content. The light regime had a more pronounced effect on ECM colonization than did juvenile damage. The interspecific competition resulted in higher ECM root tip abundance for Pinus, but this effect was insignificant in Fagus. Low light and interspecific competition resulted in lower seedling biomass compared to high light, and the effect of the latter was partially masked by high light. Leaf nitrogen responded differently in Fagus and Pinus when they grew in interspecific competition. Our results indicated that for both light-demanding (Pinus) and shade-tolerant (Fagus) species, the light environment was a major factor affecting seedling growth and ECM root tip abundance. The light conditions favorable for the growth of seedlings may to some extent compensate for the harmful effects of juvenile organ loss or damage and interspecific competition.

  20. Combined selective emitter and filter for high performance incandescent lighting

    DOE PAGES

    Leroy, Arny; Bhatia, Bikram; Wilke, Kyle; ...

    2017-09-01

    The efficiency of incandescent light bulbs (ILBs) is inherently low due to the dominant emission at infrared wavelengths, diminishing its popularity today. ILBs with cold-side filters that transmit visible light but reflect infrared radiation back to the filament can surpass the efficiency of state-of-the- art light-emitting diodes (LEDs). However, practical challenges such as imperfect geometrical alignment (view factor) between the filament and cold-side filters can limit the maximum achievable efficiency and make the use of cold-side filters ineffective. Here in this work, we show that by combining a cold-side optical filter with a selective emitter, the effect of the imperfectmore » view factor between the filament and filter on the system efficiency can be minimized. We experimentally and theoretically demonstrate energy savings of up to 67% compared to a bare tungsten emitter at 2000 K, representing a 34% improvement over a bare tungsten filament with a filter. Our work suggests that this approach can be competitive with LEDs in both luminous efficiency and color rendering index (CRI) when using selective emitters and filters already demonstrated in the literature, thus paving the way for next-generation high-efficiency ILBs.« less

  1. Combined selective emitter and filter for high performance incandescent lighting

    NASA Astrophysics Data System (ADS)

    Leroy, Arny; Bhatia, Bikram; Wilke, Kyle; Ilic, Ognjen; Soljačić, Marin; Wang, Evelyn N.

    2017-08-01

    The efficiency of incandescent light bulbs (ILBs) is inherently low due to the dominant emission at infrared wavelengths, diminishing its popularity today. ILBs with cold-side filters that transmit visible light but reflect infrared radiation back to the filament can surpass the efficiency of state-of-the-art light-emitting diodes (LEDs). However, practical challenges such as imperfect geometrical alignment (view factor) between the filament and cold-side filters can limit the maximum achievable efficiency and make the use of cold-side filters ineffective. In this work, we show that by combining a cold-side optical filter with a selective emitter, the effect of the imperfect view factor between the filament and filter on the system efficiency can be minimized. We experimentally and theoretically demonstrate energy savings of up to 67% compared to a bare tungsten emitter at 2000 K, representing a 34% improvement over a bare tungsten filament with a filter. Our work suggests that this approach can be competitive with LEDs in both luminous efficiency and color rendering index (CRI) when using selective emitters and filters already demonstrated in the literature, thus paving the way for next-generation high-efficiency ILBs.

  2. Light masking in the field: an experiment with nocturnal and diurnal spiny mice under semi-natural field conditions.

    PubMed

    Rotics, Shay; Dayan, Tamar; Levy, Ofir; Kronfeld-Schor, Noga

    2011-02-01

    Light masking has been studied almost exclusively in the laboratory. The authors populated four field enclosures with locally coexisting nocturnal Acomys cahirinus and diurnal A. russatus, and monitored their body temperatures (T(b)) using implanted temperature-sensitive radio transmitters. A 3-h light pulse was initiated at the beginning of two consecutive nights; preceding nights were controls. A. cahirinus T(b) and calculated activity levels decreased significantly during the light pulse, demonstrating a negative light masking response (light effect on T(b): -0.32 °C ± 0.15 °C; average calculated activity records during the light pulse: 7 ± 1.53, control: 9.8 ± 1.62). Diurnal A. russatus did not respond to the light pulse. We conclude that light masking is not an artifact of laboratory conditions but represents a natural adaptive response in free-living populations.

  3. Benefits of high energy UV185 nm light to inactivate bacteria.

    PubMed

    Liu, Yi; Ogden, Kimberly

    2010-01-01

    Inactivating and eliminating bacteria from ultra pure water (UPW) systems is always a significant problem for semiconductor and pharmaceutical industries. To alleviate the problem, ultraviolet (UV) radiation-both monochromatic UV254 light and high pressure UV185 light-is traditionally used for bacterial sterilization and in the case of the later, breakdown of trace organic molecules. The focus of this work is to understand the factors that influence the effectiveness of these UV treatments on Xanthomonas sp. bacteria typically found in UPW systems. In particular, the factors associated with the reactor condition, such as the light source and environment were investigated. It is shown that inactivation follows first order kinetics, and that the rates are comparable to others found in the literature for gram negative bacteria. Also, growth phase and harvesting conditions are shown to influence inactivation rate. Furthermore, it was determined that UV185 radiation, although limited by water absorption, significantly enhances the inactivation rate of bacteria if given suitable transmission distance. Rates of inactivation were enhanced by 40% when UV185 light is used in addition to UV254 light.

  4. High-definition projection screen based on multiple light scattering technique

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiromasa; Okumura, Takamitsu; Tagaya, Akihiro; Higuchi, Eizaburo; Koike, Yasuhiro

    2004-05-01

    A novel rear projection screen (Blue Ocean screen, Nitto Jyushi Kogyo, Co., Ltd.) has been developed. Blue Ocean screen is a single polymer plate requiring no lens element. The projected image is formed on the screen surface by the multiple light scattering. An image light is multiply scattered and is converted into homogeneous light distribution efficiently due to the internal particles of micron order dispersed in the acrylic polymer matrix. An ambient light is reduced by the dye molecules doped in the polymer and the anti-reflective coating on the screen surface. The condition of the particles and the concentration of the dye molecules have been optimized by the ray tracing simulation program based on Mie scattering theory using a Monte Carlo method. The screen containing the particles of optimum condition exhibits the wide viewing angle, the well-controlled color balance, and the high sharpness level at the same time. The contrast level of the projected image in ambient light is improved by controlling the concentration of the dye molecules. This paper describes the optimization obtained theoretically and experimentally, and demonstrates the advantage of Blue Ocean screen.

  5. High-speed multilevel 512x512 spatial light modulator

    NASA Astrophysics Data System (ADS)

    Bauchert, Kipp A.; Serati, Steven A.

    2000-03-01

    Recent advances in our high-speed multi-level (analog) 512 X 512 liquid crystal spatial light modulator (SLM) will be presented. These advancements include smaller pixel pitch, greatly improved optical efficiency, and higher speed operation. The new VLSI SLM can utilize Ferroelectric Liquid Crystal to Nematic Liquid Crystal to achieve phase-only, amplitude-only, and phase-amplitude-coupled modulation. This device has applications in optical processing, optical storage, holographic display, and beam steering. Design criteria and experimental data will be presented.

  6. Total funneling of light in high aspect ratio plasmonic nanoresonators

    NASA Astrophysics Data System (ADS)

    Bouchon, Patrick; Pardo, Fabrice; Portier, Benjamin; Ferlazzo, Laurence; Ghenuche, Petru; Dagher, Gulnar; Dupuis, Christophe; Bardou, Nathalie; Haïdar, Riad; Pelouard, Jean-Luc

    2011-05-01

    We demonstrate the total extinction of the reflectivity for a transverse magnetic polarized wave on a gold surface etched on 6% of its area by both narrow (150 nm) and deep (2 μm) grooves. These high aspect ratio metallic grooves were fabricated using a mold cast technique based on an electrolytic growth of gold. They exhibit two resonance peaks corresponding to the first and second cavity modes inside the grooves. We also evidence the incidence-invariance of their spectral response, which undoubtedly shows the localized nature of the resonances. These experimental results confirm the prediction of total funneling of light in very narrow grooves.

  7. Highly efficient exciplex phosphorescence from organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Virgili, D.; Cocchi, M.; Fattori, V.; Sabatini, C.; Kalinowski, J.; Williams, J. A. G.

    2006-12-01

    The efficiency of organic exciplex light-emitting-devices (EXLEDs) can be greatly improved by introduction of a phosphorescent sensitizer with a high electronic affinity. In the electron-hole combination process at the electron donor/acceptor interface, solely singlet exciplexes are generated producing the exciplex fluorescence. A phosphor sensitizer allows the formation in the emitter bulk of triplet exciplexes, which yield highly efficient exciplex phosphorescence. As an example, we use a Pt-based phosphor (PtL 2Cl) doped into a star-burst amine hole transporting donor (m-MTDATA) and bathophenanthroline (BPT) electron-transporting acceptor system which in a bi-layer EXLED reveals an exciplex high electro-phosphorescence external quantum yield of 2.4% photon/carrier.

  8. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition

    PubMed Central

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Yan, Zuoqin; Qian, Ruizhe

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation. PMID:27631008

  9. Altered Clock and Lipid Metabolism-Related Genes in Atherosclerotic Mice Kept with Abnormal Lighting Condition.

    PubMed

    Zhu, Zhu; Hua, Bingxuan; Shang, Zhanxian; Yuan, Gongsheng; Xu, Lirong; Li, Ermin; Li, Xiaobo; Sun, Ning; Yan, Zuoqin; Qian, Ruizhe; Lu, Chao

    2016-01-01

    Background. The risk of atherosclerosis is elevated in abnormal lipid metabolism and circadian rhythm disorder. We investigated whether abnormal lighting condition would have influenced the circadian expression of clock genes and clock-controlled lipid metabolism-related genes in ApoE-KO mice. Methods. A mouse model of atherosclerosis with circadian clock genes expression disorder was established using ApoE-KO mice (ApoE-KO LD/DL mice) by altering exposure to light. C57 BL/6J mice (C57 mice) and ApoE-KO mice (ApoE-KO mice) exposed to normal day and night and normal diet served as control mice. According to zeitgeber time samples were acquired, to test atheromatous plaque formation, serum lipids levels and rhythmicity, clock genes, and lipid metabolism-related genes along with Sirtuin 1 (Sirt1) levels and rhythmicity. Results. Atherosclerosis plaques were formed in the aortic arch of ApoE-KO LD/DL mice. The serum lipids levels and oscillations in ApoE-KO LD/DL mice were altered, along with the levels and diurnal oscillations of circadian genes, lipid metabolism-associated genes, and Sirt1 compared with the control mice. Conclusions. Abnormal exposure to light aggravated plaque formation and exacerbated disorders of serum lipids and clock genes, lipid metabolism genes and Sirt1 levels, and circadian oscillation.

  10. Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures.

    PubMed

    Nelson, Jacob A; Bugbee, Bruce

    2014-01-01

    Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400-700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture.

  11. Economic Analysis of Greenhouse Lighting: Light Emitting Diodes vs. High Intensity Discharge Fixtures

    PubMed Central

    Nelson, Jacob A.; Bugbee, Bruce

    2014-01-01

    Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400–700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture. PMID:24905835

  12. Acclimation responses to high light by Guazuma ulmifolia Lam. (Malvaceae) leaves at different stages of development.

    PubMed

    Calzavara, A K; Rocha, J S; Lourenço, G; Sanada, K; Medri, C; Bianchini, E; Pimenta, J A; Stolf-Moreira, R; Oliveira, H C

    2017-09-01

    The re-composition of deforested environments requires the prior acclimation of seedlings to full sun in nurseries. Seedlings can overcome excess light either through the acclimation of pre-existing fully expanded leaves or through the development of new leaves that are acclimated to the new light environment. Here, we compared the acclimation capacity of mature (MatL, fully expanded at the time of transfer) and newly expanded (NewL, expanded after the light shift) leaves of Guazuma ulmifolia Lam. (Malvaceae) seedlings to high light. The seedlings were initially grown under shade and then transferred to full sunlight. MatL and NewL were used for chlorophyll fluorescence and gas exchange analyses, pigment extraction and morpho-anatomical measurements. After the transfer of seedlings to full sun, the MatL persisted and acclimated to some extent to the new light condition, since they underwent alterations in some morpho-physiological traits and maintained a functional electron transport chain and positive net photosynthesis rate. However, long-term exposure to high light led to chronic photoinhibition in MatL, which could be related to the limited plasticity of leaf morpho-anatomical attributes. However, the NewL showed a high capacity to use the absorbed energy in photochemistry and dissipate excess energy harmlessly, attributes that were favoured by the high structural plasticity exhibited by these leaves. Both the maintenance of mature, photosynthetically active leaves and the production of new leaves with a high capacity to cope with excess energy were important for acclimation of G. ulmifolia seedlings. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. A newly proposed disease condition produced by light exposure during night: asynchronization.

    PubMed

    Kohyama, Jun

    2009-04-01

    The bedtime of preschoolers/pupils/students in Japan has become progressively later with the result sleep duration has become progressively shorter. With these changes, more than half of the preschoolers/pupils/students in Japan recently have complained of daytime sleepiness, while approximately one quarter of junior and senior high school students in Japan reportedly suffer from insomnia. These preschoolers/pupils/students may be suffering from behaviorally induced insufficient sleep syndrome due to inadequate sleep hygiene. If this diagnosis is correct, they should be free from these complaints after obtaining sufficient sleep by avoiding inadequate sleep hygiene. However, such a therapeutic approach often fails. Although social factors are often involved in these sleep disturbances, a novel clinical notion--asynchronization--can further a deeper understanding of the pathophysiology of these disturbances. The essence of asynchronization is a disturbance in various aspects (e.g., cycle, amplitude, phase and interrelationship) of the biological rhythms that normally exhibit circadian oscillation, presumably involving decreased activity of the serotonergic system. The major trigger of asynchronization is hypothesized to be a combination of light exposure during the night and a lack of light exposure in the morning. In addition to basic principles of morning light and an avoidance of nocturnal light exposure, presumable potential therapeutic approaches for asynchronization involve both conventional ones (light therapy, medications (hypnotics, antidepressants, melatonin, vitamin B12), physical activation, chronotherapy) and alternative ones (kampo, pulse therapy, direct contact, control of the autonomic nervous system, respiration (qigong, tanden breathing), chewing, crawling). A morning-type behavioral preference is described in several of the traditional textbooks for good health. The author recommends a morning-type behavioral lifestyle as a way to reduce

  14. Seagrass dynamics in shallow coastal lagoons: Interactions with fluid dynamics, sediment resuspension and light conditions

    NASA Astrophysics Data System (ADS)

    Carr, J. A.; D'Odorico, P.; McGlathery, K.; Wiberg, P. L.

    2010-12-01

    Sea grasses have been recognized for their ability to stabilize the benthic sediments of shallow coastal lagoons, thereby reducing the turbidity of the water column and providing a light environment that is more favorable for sea grass establishment and growth. Sea grasses are complex, in that they involve different strategies of carbon allocation between below and above ground biomass, and the partitioning of the overall biomass into a discrete number of stems and leaves. Stem density and canopy height, in turn, modify the flow field, sediment resuspension, and the light environment. It is still unclear how these seasonal and interannual dynamics of seagrass vegetation may be affected by and interact with the process of sediment resuspension under fluctuating climatic and hydrologic conditions. To this end, a coupled model hydrodynamic model of vegetation-sediment-water flow interactions and vegetation growth is developed and used to examine the feedback between seagrass vegetation density and sediment resuspension and water column turbidity. The daily growth model is designed to capture underground biomass and the growth and senescence of above ground biomass structural components (e.g., leaves and stems). This allows for investigating how the interseasonal and seasonal variability in shoot and leaf density within a meadow affects the strength of positive feedback between seagrass and their light environment. Eight years of hourly wind, light, tides and water temperature are used to drive the coupled model from an initial mature meadow state as well as a seedling state. The model demonstrates both the emergence of bistable behavior as well as the limited resilience of seagrass meadows due to the strength of the positive feedback. The effects of increased water depths and water temperatures on the health and resilience of a seagrass meadow were also investigated. As both water depth and water temperatures increase, the system only exhibits bistable behavior with

  15. Light-induced disulfide dimerization of recoverin under ex vivo and in vivo conditions.

    PubMed

    Zernii, Evgeni Yu; Nazipova, Aliya A; Gancharova, Olga S; Kazakov, Alexey S; Serebryakova, Marina V; Zinchenko, Dmitry V; Tikhomirova, Natalya K; Senin, Ivan I; Philippov, Pavel P; Permyakov, Eugene A; Permyakov, Sergei E

    2015-06-01

    Despite vast knowledge of the molecular mechanisms underlying photochemical damage of photoreceptors, linked to progression of age-related macular degeneration, information on specific protein targets of the light-induced oxidative stress is scarce. Here, we demonstrate that prolonged intense illumination (halogen bulb, 1500 lx, 1-5 h) of mammalian eyes under ex vivo (cow) or in vivo (rabbit) conditions induces disulfide dimerization of recoverin, a Ca(2+)-dependent inhibitor of rhodopsin kinase. Western blotting and mass spectrometry analysis of retinal extracts reveals illumination time-dependent accumulation of disulfide homodimers of recoverin and its higher order disulfide cross-linked species, including a minor fraction of mixed disulfides with intracellular proteins (tubulins, etc.). Meanwhile, monomeric bovine recoverin remains mostly reduced. These effects are accompanied by accumulation of disulfide homodimers of visual arrestin. Histological studies demonstrate that the light-induced oxidation of recoverin and arrestin occurs in intact retina (illumination for 2 h), while illumination for 5 h is associated with damage of the photoreceptor layer. A comparison of ex vivo levels of disulfide homodimers of bovine recoverin with redox dependence of its in vitro thiol-disulfide equilibrium (glutathione redox pair) gives the lowest estimate of redox potential in rod outer segments under illumination from -160 to -155 mV. Chemical crosslinking and dynamic light scattering data demonstrate an increased propensity of disulfide dimer of bovine recoverin to multimerization/aggregation. Overall, the oxidative stress caused by the prolonged intense illumination of retina might affect rhodopsin desensitization via concerted disulfide dimerization of recoverin and arrestin. The developed herein models of eye illumination are useful for studies of the light-induced thiol oxidation of visual proteins.

  16. Effects of post-harvest light conditions on quality and aromatic volatile formation in 'Hakuho' peach (Prunus persica Batsch) fruits.

    PubMed

    Li, Bin; Jia, Hui-Juan; Okamoto, Goro

    2007-06-01

    The effect of light condition during post-harvest storage on fruit quality of 'Hakuho' peach (Prunus persica Batsch) was examined. Fruits were harvested at the immature stage (7 d before the tree-ripening stage) and firm-ripe (3 d before the tree-ripening) stage and stored at 25 degrees C under light (ca 80 micromol m(-2) s(-1) at the fruit top by a fluorescent lamp) and in darkness. The light and dark conditions did not significantly influence the ethylene production rate except for the fully ripened fruits harvested at firm-ripe stage and stored under light. However, no difference in fruit firmness was detected among treatments at full-ripe stage. The skin anthocyanin content increased significantly during storage under light. Total soluble solid (TSS) content of juice at the full ripe stage was not affected significantly by the storage condition, although titratable acidity (TA) in immature harvested fruits decreased more quickly during storage under light compared with those stored in darkness. Dark storage limited the decrease in juice asparagine to some extent. Aromatic lactones, such as gamma-decalactone and gamma-dodecalactone, both in skin and in flesh tissues increased more rapidly when the fruits were stored under a light condition, irrespective of fruit harvest stage. From these results, we conclude that fruit storage under a light condition is better for fruit quality of the 'Hakuho' peaches than storage in darkness.

  17. Hydrogen production by the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142 under conditions of continuous light.

    PubMed

    Min, Hongtao; Sherman, Louis A

    2010-07-01

    We report on the hydrogen production properties of the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142. This organism has a versatile metabolism and can grow in the presence or absence of combined nitrogen and can grow photosynthetically or mixotrophically and heterotrophically in the presence of glycerol. The strain produces a bidirectional hydrogenase (encoded by the hox genes), an uptake hydrogenase (hupLS), and nitrogenase (nifHDK). We demonstrated hydrogen production by both the hydrogenase and the nitrogenase under appropriate metabolic conditions. The highest rates of hydrogen production were produced under nitrogen-fixing conditions when cells were grown and incubated under continuous light conditions, in either the presence or absence of glycerol. Under such nitrogen-fixing conditions, we have achieved rates of 300 micromol H(2)/mg chloramphenicol (Chl)/hr during the first 24 h of incubation. The levels of H(2) measured were dependent upon the incubation conditions, such as sparging with argon, which generated anaerobic conditions. We demonstrated that the same conditions led to high levels of H(2) production and N(2) fixation, indicating that low-oxygen conditions favor nitrogenase activity for both processes. The levels of hydrogen produced by the hydrogenase are much lower, typically 5 to 10 micromol H(2)/mg Chl/hr. Hydrogenase activity was dependent upon electron transport through photosystem II (PS II), whereas nitrogenase activity was more dependent on PS I, as well as on respiration. Although cells do not double under the incubation conditions when sparged with argon to provide a low-oxygen environment, the cells are metabolically active, and hydrogen production can be inhibited by the addition of chloramphenicol to inhibit protein synthesis.

  18. High-performance lighting evaluated by photobiological parameters.

    PubMed

    Rebec, Katja Malovrh; Gunde, Marta Klanjšek

    2014-08-10

    The human reception of light includes image-forming and non-image-forming effects which are triggered by spectral distribution and intensity of light. Ideal lighting is similar to daylight, which could be evaluated by spectral or chromaticity match. LED-based and CFL-based lighting were analyzed here, proposed according to spectral and chromaticity match, respectively. The photobiological effects were expressed by effectiveness for blue light hazard, cirtopic activity, and photopic vision. Good spectral match provides light with more similar effects to those obtained by the chromaticity match. The new parameters are useful for better evaluation of complex human responses caused by lighting.

  19. High-Voltage LED Light Engine with Integrated Driver

    SciTech Connect

    Soer, Wouter

    2016-02-29

    LED luminaires have seen dramatic changes in cost breakdown over the past few years. The LED component cost, which until recently was the dominant portion of luminaire cost, has fallen to a level of the same order as the other luminaire components, such as the driver, housing, optics etc. With the current state of the technology, further luminaire performance improvement and cost reduction is realized most effectively by optimization of the whole system, rather than a single component. This project focuses on improving the integration between LEDs and drivers. Lumileds has developed a light engine platform based on low-cost high-power LEDs and driver topologies optimized for integration with these LEDs on a single substrate. The integration of driver and LEDs enables an estimated luminaire cost reduction of about 25% for targeted applications, mostly due to significant reductions in driver and housing cost. The high-power LEDs are based on Lumileds’ patterned sapphire substrate flip-chip (PSS-FC) technology, affording reduced die fabrication and packaging cost compared to existing technology. Two general versions of PSS-FC die were developed in order to create the desired voltage and flux increments for driver integration: (i) small single-junction die (0.5 mm2), optimal for distributed lighting applications, and (ii) larger multi-junction die (2 mm2 and 4 mm2) for high-power directional applications. Two driver topologies were developed: a tapped linear driver topology and a single-stage switch-mode topology, taking advantage of the flexible voltage configurations of the new PSS-FC die and the simplification opportunities enabled by integration of LEDs and driver on the same board. A prototype light engine was developed for an outdoor “core module” application based on the multi-junction PSS-FC die and the single-stage switch-mode driver. The light engine meets the project efficacy target of 128 lm/W at a luminous flux

  20. Digital image database processing to simulate image formation in ideal lighting conditions of the human eye

    NASA Astrophysics Data System (ADS)

    Castañeda-Santos, Jessica; Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Hernández-Méndez, Arturo

    2015-09-01

    The pupil size of the human eye has a large effect in the image quality due to inherent aberrations. Several studies have been performed to calculate its size relative to the luminance as well as considering other factors, i.e., age, size of the adapting field and mono and binocular vision. Moreover, ideal lighting conditions are known, but software suited to our specific requirements, low cost and low computational consumption, in order to simulate radiation adaptation and image formation in the retina with ideal lighting conditions has not yet been developed. In this work, a database is created consisting of 70 photographs corresponding to the same scene with a fixed target at different times of the day. By using this database, characteristics of the photographs are obtained by measuring the luminance average initial threshold value of each photograph by means of an image histogram. Also, we present the implementation of a digital filter for both, image processing on the threshold values of our database and generating output images with the threshold values reported for the human eye in ideal cases. Some potential applications for this kind of filters may be used in artificial vision systems.

  1. Automatic exposure for panoramic systems in uncontrolled lighting conditions: a football stadium case study

    NASA Astrophysics Data System (ADS)

    Gaddam, Vamsidhar Reddy; Griwodz, Carsten; Halvorsen, Pâl.

    2014-02-01

    One of the most common ways of capturing wide eld-of-view scenes is by recording panoramic videos. Using an array of cameras with limited overlapping in the corresponding images, one can generate good panorama images. Using the panorama, several immersive display options can be explored. There is a two fold synchronization problem associated to such a system. One is the temporal synchronization, but this challenge can easily be handled by using a common triggering solution to control the shutters of the cameras. The other synchronization challenge is the automatic exposure synchronization which does not have a straight forward solution, especially in a wide area scenario where the light conditions are uncontrolled like in the case of an open, outdoor football stadium. In this paper, we present the challenges and approaches for creating a completely automatic real-time panoramic capture system with a particular focus on the camera settings. One of the main challenges in building such a system is that there is not one common area of the pitch that is visible to all the cameras that can be used for metering the light in order to nd appropriate camera parameters. One approach we tested is to use the green color of the eld grass. Such an approach provided us with acceptable results only in limited light conditions.A second approach was devised where the overlapping areas between adjacent cameras are exploited, thus creating pairs of perfectly matched video streams. However, there still existed some disparity between di erent pairs. We nally developed an approach where the time between two temporal frames is exploited to communicate the exposures among the cameras where we achieve a perfectly synchronized array. An analysis of the system and some experimental results are presented in this paper. In summary, a pilot-camera approach running in auto-exposure mode and then distributing the used exposure values to the other cameras seems to give best visual results.

  2. High average power solid state laser power conditioning system

    SciTech Connect

    Steinkraus, R.F.

    1987-03-03

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers.

  3. Responses of Ulva prolifera to short-term nutrient enrichment under light and dark conditions

    NASA Astrophysics Data System (ADS)

    Sun, Kai-Ming; Li, Ruixiang; Li, Yan; Xin, Ming; Xiao, Jie; Wang, Zongling; Tang, Xuexi; Pang, Min

    2015-09-01

    To define responses of short-term nutrient uptake in Ulva prolifera, we measured uptake rates, enzyme activity, and tissue nutrient content in lab experiments where we manipulated nutrient supply and irradiation. Nitrate uptake of U. prolifera was significantly impacted by the external nitrate concentrations, and ammonium uptake was mainly determined by the light availability. The measured nitrogen contents in tissues were higher than the calculated values from the uptake of dissolve inorganic nitrogen, indicating that U. prolifera might use multiple nitrogen sources. High external phosphate concentrations and sufficient light can accelerate the phosphate uptake of U. prolifera, while the measured phosphorus contents in tissues were lower than the calculated values from the uptake of phosphate, suggesting a possibility of internal phosphorus release. The enzymatic activities of nitrate reductase (NR), acid phosphatase (AcP) and alkaline phosphatase (AP) showed little changes, indicating that enzymatic activity might not a direct factor determining the short-term nutrient uptake of U. prolifera.

  4. Ghrelin receptor-knockout mice display alterations in circadian rhythms of activity and feeding under constant lighting conditions.

    PubMed

    Lamont, E Waddington; Bruton, J; Blum, I D; Abizaid, A

    2014-01-01

    Ghrelin is an orexigenic hormone produced by the stomach. Ghrelin, however, may also be a modulator of the circadian system given that ghrelin receptors are expressed in the master clock, the suprachiasmatic nucleus (SCN) and several outputs of this region. To investigate this, we performed analyses of running wheel activity and neuronal activation in wild type (WT) and growth hormone secretagogue receptor-knockout (GHSR-KO) mice under various lighting conditions. GHSR-KO and WT mice were maintained under constant dark (DD) or constant light (LL) with ad libitum access to food before being placed on a schedule of temporally restricted access to food (4 h/day) for 2 weeks. There were no differences between KO and WT mice in free-running period under DD, but GHSR-KO mice required more days to develop a high level of food anticipatory activity, and this was lower than that observed in WT mice. Under LL, GHSR-KO mice showed greater activity overall, lengthening of their circadian period, and more resistance to the disorganisational effects of LL. Furthermore, GHSR-KO mice showed greater activity overall, and greater activity in anticipation of a scheduled meal under LL. These behavioral effects were not correlated with changes in the circadian expression of the Fos, Per1 or Per2 proteins under any lighting conditions. These results suggest that the ghrelin receptor plays a role in modulating the activity of the circadian system under normal conditions and under restricted feeding schedules, but does so through mechanisms that remain to be determined.

  5. Systemic regulation of leaf anatomical structure, photosynthetic performance, and high-light tolerance in sorghum.

    PubMed

    Jiang, Chuang-Dao; Wang, Xin; Gao, Hui-Yuan; Shi, Lei; Chow, Wah Soon

    2011-03-01

    Leaf anatomy of C3 plants is mainly regulated by a systemic irradiance signal. Since the anatomical features of C4 plants are different from that of C3 plants, we investigated whether the systemic irradiance signal regulates leaf anatomical structure and photosynthetic performance in sorghum (Sorghum bicolor), a C4 plant. Compared with growth under ambient conditions (A), no significant changes in anatomical structure were observed in newly developed leaves by shading young leaves alone (YS). Shading mature leaves (MS) or whole plants (S), on the other hand, caused shade-leaf anatomy in newly developed leaves. By contrast, chloroplast ultrastructure in developing leaves depended only on their local light conditions. Functionally, shading young leaves alone had little effect on their net photosynthetic capacity and stomatal conductance, but shading mature leaves or whole plants significantly decreased these two parameters in newly developed leaves. Specifically, the net photosynthetic rate in newly developed leaves exhibited a positive linear correlation with that of mature leaves, as did stomatal conductance. In MS and S treatments, newly developed leaves exhibited severe photoinhibition under high light. By contrast, newly developed leaves in A and YS treatments were more resistant to high light relative to those in MS- and S-treated seedlings. We suggest that (1) leaf anatomical structure, photosynthetic capacity, and high-light tolerance in newly developed sorghum leaves were regulated by a systemic irradiance signal from mature leaves; and (2) chloroplast ultrastructure only weakly influenced the development of photosynthetic capacity and high-light tolerance. The potential significance of the regulation by a systemic irradiance signal is discussed.

  6. Expression profiling of the bloom-forming cyanobacterium Nodularia CCY9414 under light and oxidative stress conditions

    PubMed Central

    Kopf, Matthias; Möke, Fred; Bauwe, Hermann; Hess, Wolfgang R; Hagemann, Martin

    2015-01-01

    Massive blooms of toxic cyanobacteria frequently occur in the central Baltic Sea during the summer. In the surface scum, cyanobacterial cells are exposed to high light (HL) intensity, high oxygen partial pressure and other stresses. To mimic these conditions, cultures of Nodularia spumigena CCY9414, which is a strain isolated from a cyanobacterial summer bloom in the Baltic Sea, were incubated at a HL intensity of 1200 μmol photons m−2 s−1 or a combination of HL and increased oxygen partial pressure. Using differential RNA sequencing, we compared the global primary transcriptomes of control and stressed cells. The combination of oxidative and light stresses induced the expression of twofold more genes compared with HL stress alone. In addition to the induction of known stress-responsive genes, such as psbA, ocp and sodB, Nodularia cells activated the expression of genes coding for many previously unknown light- and oxidative stress-related proteins. In addition, the expression of non-protein-coding RNAs was found to be stimulated by these stresses. Among them was an antisense RNA to the phycocyanin-encoding mRNA cpcBAC and the trans-encoded regulator of photosystem I, PsrR1. The large genome capacity allowed Nodularia to harbor more copies of stress-relevant genes such as psbA and small chlorophyll-binding protein genes, combined with the coordinated induction of these and many additional genes for stress acclimation. Our data provide a first insight on how N. spumigena became adapted to conditions relevant for a cyanobacterial bloom in the Baltic Sea. PMID:25689027

  7. Differences in photosynthetic responses of NADP-ME type C4 species to high light.

    PubMed

    Romanowska, Elżbieta; Buczyńska, Alicja; Wasilewska, Wioleta; Krupnik, Tomasz; Drożak, Anna; Rogowski, Paweł; Parys, Eugeniusz; Zienkiewicz, Maksymilian

    2017-03-01

    Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m(-2) s(-1)) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m(-2) s(-1)). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H2O2 suggests that antioxidant defense is not

  8. Melanocytes from dark and light skin respond differently after ultraviolet B irradiation: effect of keratinocyte-conditioned medium.

    PubMed

    López, Saioa; Alonso, Santos; García de Galdeano, Alicia; Smith-Zubiaga, Isabel

    2015-05-01

    The response to the damage provoked by exposure to UV radiation is mediated by melanocytes and a network of paracrine factors produced by keratinocytes, and it varies among individuals of different geographical origin and skin colour. The mechanisms underlying this differential response, however, have not been completely elucidated. We characterized the differential behaviour of melanocytes (proliferation and differentiation/melanogenesis) from both dark- and light-skinned individuals in response to ultraviolet B (UVB) irradiation, cultured with and without keratinocyte-conditioned medium (KCM). ELISA assays and real-time quantitative PCR were used to assess the production of keratinocyte-derived factors. After UVB irradiation, dark melanocytes showed a decreased proliferation consistent with the highly differentiated state inferred by the increased dendricity of the cells and higher levels of melanogenic genes expression, whereas light melanocytes showed an increase in proliferation in accord with a less differentiated state and decreased melanogenesis levels. KCM induced melanogenesis in dark melanocytes after UVB irradiation, but not in light-pigmented melanocytes. Proliferation and differentiation are coordinated in response to UVB. A lower proliferative rate and a higher differentiation state in dark melanocytes could account for more effective photoprotective mechanisms that would prevent from cell damage against UVB irradiation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Highly conductive copper nano/microparticles ink via flash light sintering for printed electronics

    NASA Astrophysics Data System (ADS)

    Joo, Sung-Jun; Hwang, Hyun-Jun; Kim, Hak-Sung

    2014-07-01

    In this study, the size effect of copper particles on the flash light sintering of copper (Cu) ink was investigated using Cu nanoparticles (20-50 nm diameter) and microparticles (2 μm diameter). Also, the mixed Cu nano-/micro-inks were fabricated, and the synergetic effects between the Cu nano-ink and micro-ink on flash light sintering were assessed. The ratio of nanoparticles to microparticles in Cu ink and the several flash light irradiation conditions (irradiation energy density, pulse number, on-time, and off-time) were optimized to obtain high conductivity of Cu films. In order to precisely monitor the milliseconds-long flash light sintering process, in situ monitoring of electrical resistance and temperature changes of Cu films was conducted during the flash light irradiation using a real-time Wheatstone bridge electrical circuit, thermocouple-based circuit, and a high-rate data acquisition system. Also, several microscopic and spectroscopic characterization techniques such as scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the flash light sintered Cu nano-/micro-films. In addition, the sheet resistance of Cu film was measured using a four-point probe method. This work revealed that the optimal ratio of nanoparticles to microparticles is 50:50 wt%, and the optimally fabricated and flash light sintered Cu nano-/micro-ink films have the lowest resistivity (80 μΩ cm) among nano-ink, micro-ink, or nano-micro mixed films.

  10. Highly conductive copper nano/microparticles ink via flash light sintering for printed electronics.

    PubMed

    Joo, Sung-Jun; Hwang, Hyun-Jun; Kim, Hak-Sung

    2014-07-04

    In this study, the size effect of copper particles on the flash light sintering of copper (Cu) ink was investigated using Cu nanoparticles (20-50 nm diameter) and microparticles (2 μm diameter). Also, the mixed Cu nano-/micro-inks were fabricated, and the synergetic effects between the Cu nano-ink and micro-ink on flash light sintering were assessed. The ratio of nanoparticles to microparticles in Cu ink and the several flash light irradiation conditions (irradiation energy density, pulse number, on-time, and off-time) were optimized to obtain high conductivity of Cu films. In order to precisely monitor the milliseconds-long flash light sintering process, in situ monitoring of electrical resistance and temperature changes of Cu films was conducted during the flash light irradiation using a real-time Wheatstone bridge electrical circuit, thermocouple-based circuit, and a high-rate data acquisition system. Also, several microscopic and spectroscopic characterization techniques such as scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the flash light sintered Cu nano-/micro-films. In addition, the sheet resistance of Cu film was measured using a four-point probe method. This work revealed that the optimal ratio of nanoparticles to microparticles is 50:50 wt%, and the optimally fabricated and flash light sintered Cu nano-/micro-ink films have the lowest resistivity (80 μΩ cm) among nano-ink, micro-ink, or nano-micro mixed films.

  11. The matter in extreme conditions instrument at the Linac Coherent Light Source

    SciTech Connect

    Nagler, Bob; Arnold, Brice; Bouchard, Gary; Boyce, Richard F.; Boyce, Richard M.; Callen, Alice; Campell, Marc; Curiel, Ruben; Galtier, Eric; Garofoli, Justin; Granados, Eduardo; Hastings, Jerry; Hays, Greg; Heimann, Philip; Lee, Richard W.; Milathianaki, Despina; Plummer, Lori; Schropp, Andreas; Wallace, Alex; Welch, Marc; White, William; Xing, Zhou; Yin, Jing; Young, James; Zastrau, Ulf; Lee, Hae Ja

    2015-04-21

    The LCLS beam provides revolutionary capabilities for studying the transient behavior of matter in extreme conditions. The particular strength of the Matter in Extreme Conditions instrument is that it combines the unique LCLS beam with high-power optical laser beams, and a suite of dedicated diagnostics tailored for this field of science. In this paper an overview of the beamline, the capabilities of the instrumentation, and selected highlights of experiments and commissioning results are presented.

  12. The Matter in Extreme Conditions instrument at the Linac Coherent Light Source

    PubMed Central

    Nagler, Bob; Arnold, Brice; Bouchard, Gary; Boyce, Richard F.; Boyce, Richard M.; Callen, Alice; Campell, Marc; Curiel, Ruben; Galtier, Eric; Garofoli, Justin; Granados, Eduardo; Hastings, Jerry; Hays, Greg; Heimann, Philip; Lee, Richard W.; Milathianaki, Despina; Plummer, Lori; Schropp, Andreas; Wallace, Alex; Welch, Marc; White, William; Xing, Zhou; Yin, Jing; Young, James; Zastrau, Ulf; Lee, Hae Ja

    2015-01-01

    The LCLS beam provides revolutionary capabilities for studying the transient behavior of matter in extreme conditions. The particular strength of the Matter in Extreme Conditions instrument is that it combines the unique LCLS beam with high-power optical laser beams, and a suite of dedicated diagnostics tailored for this field of science. In this paper an overview of the beamline, the capabilities of the instrumentation, and selected highlights of experiments and commissioning results are presented. PMID:25931063

  13. Photocatalytic Properties of g-C₃N₄-TiO₂ Heterojunctions under UV and Visible Light Conditions.

    PubMed

    Fagan, Rachel; McCormack, Declan E; Hinder, Steven J; Pillai, Suresh C

    2016-04-14

    Graphitic carbon nitride (g-C₃N₄) and titanium dioxide (TiO₂) were chosen as a model system to investigate photocatalytic abilities of heterojunction system under UV and visible light conditions. The use of g-C₃N₄ has been shown to be effective in the reduction in recombination through the interaction between the two interfaces of TiO₂ and g-C₃N₄. A simple method of preparing g-C₃N₄ through the pyrolysis of melamine was employed, which was then added to undoped TiO₂ material to form the g-C₃N₄-TiO₂ system. These materials were then fully characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and various spectroscopic techniques including Raman, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), diffuse absorbance, and photoluminescence analysis. Photocatalysis studies were conducted using the model dye, rhodamine 6G utilizing visible and UV light irradiation. Raman spectroscopy confirmed that a composite of the materials was formed as opposed to a mixture of the two. Using XPS analysis, a shift in the nitrogen peak to that indicative of substitutional nitrogen was detected for all doped samples. This is then mirrored in the diffuse absorbance results, which show a clear decrease in band gap values for these samples, showing the effective band gap alteration achieved through this preparation process. When g-C₃N₄-TiO₂ samples were analyzed under visible light irradiation, no significant improvement was observed compared that of pure TiO₂. However, under UV light irradiation conditions, the photocatalytic ability of the doped samples exhibited an increased reactivity when compared to the undoped TiO₂ (0.130 min(-1)), with 4% g-C₃N₄-TiO₂ (0.187 min(-1)), showing a 43.9% increase in reactivity. Further doping to 8% g-C₃N₄-TiO₂ lead to a decrease in reactivity against rhodamine 6G. BET analysis determined that the surface area of the 4% and 8% g

  14. In High-Light-Acclimated Coffee Plants the Metabolic Machinery Is Adjusted to Avoid Oxidative Stress Rather than to Benefit from Extra Light Enhancement in Photosynthetic Yield

    PubMed Central

    Martins, Samuel C. V.; Araújo, Wagner L.; Tohge, Takayuki; Fernie, Alisdair R.; DaMatta, Fábio M.

    2014-01-01

    Coffee (Coffea arabica L.) has been traditionally considered as shade-demanding, although it performs well without shade and even out-yields shaded coffee. Here we investigated how coffee plants adjust their metabolic machinery to varying light supply and whether these adjustments are supported by a reprogramming of the primary and secondary metabolism. We demonstrate that coffee plants are able to adjust its metabolic machinery to high light conditions through marked increases in its antioxidant capacity associated with enhanced consumption of reducing equivalents. Photorespiration and alternative pathways are suggested to be key players in reductant-consumption under high light conditions. We also demonstrate that both primary and secondary metabolism undergo extensive reprogramming under high light supply, including depression of the levels of intermediates of the tricarboxylic acid cycle that were accompanied by an up-regulation of a range of amino acids, sugars and sugar alcohols, polyamines and flavonoids such as kaempferol and quercetin derivatives. When taken together, the entire dataset is consistent with these metabolic alterations being primarily associated with oxidative stress avoidance rather than representing adjustments in order to facilitate the plants from utilizing the additional light to improve their photosynthetic performance. PMID:24733284

  15. In high-light-acclimated coffee plants the metabolic machinery is adjusted to avoid oxidative stress rather than to benefit from extra light enhancement in photosynthetic yield.

    PubMed

    Martins, Samuel C V; Araújo, Wagner L; Tohge, Takayuki; Fernie, Alisdair R; DaMatta, Fábio M

    2014-01-01

    Coffee (Coffea arabica L.) has been traditionally considered as shade-demanding, although it performs well without shade and even out-yields shaded coffee. Here we investigated how coffee plants adjust their metabolic machinery to varying light supply and whether these adjustments are supported by a reprogramming of the primary and secondary metabolism. We demonstrate that coffee plants are able to adjust its metabolic machinery to high light conditions through marked increases in its antioxidant capacity associated with enhanced consumption of reducing equivalents. Photorespiration and alternative pathways are suggested to be key players in reductant-consumption under high light conditions. We also demonstrate that both primary and secondary metabolism undergo extensive reprogramming under high light supply, including depression of the levels of intermediates of the tricarboxylic acid cycle that were accompanied by an up-regulation of a range of amino acids, sugars and sugar alcohols, polyamines and flavonoids such as kaempferol and quercetin derivatives. When taken together, the entire dataset is consistent with these metabolic alterations being primarily associated with oxidative stress avoidance rather than representing adjustments in order to facilitate the plants from utilizing the additional light to improve their photosynthetic performance.

  16. Features of anthocyanin biosynthesis in pap1-D and wild-type Arabidopsis thaliana plants grown in different light intensity and culture media conditions.

    PubMed

    Shi, Ming-Zhu; Xie, De-Yu

    2010-05-01

    The number of different anthocyanin molecules potentially produced by Arabidopsis thaliana and which anthocyanin molecule is the first product of anthocyanidin modification remain unknown. To accelerate the understanding of these questions, we investigated anthocyanin biosynthesis in rosette leaves of both pap1-D and wild-type (WT) A. thaliana plants grown in nine growth conditions, which were composed of three light intensities (low light, middle light, and high light) and three media derived from MS medium (medium-1, 2, and 3). These nine growth conditions differentially affected the levels of anthocyanins and pigmentation patterns of rosette leaves, which were closely related to the diversification levels of cyanin structures. The combined growth conditions of high light and either medium-2 or medium-1 induced the most molecular diversity of anthocyanin structures in rosette leaves of pap1-D plants. Twenty cyanin molecules, including five that were previously unknown, were characterized by HPLC-ESI-MS and HPLC-TOF-MS analyses. We detected that the A. thaliana anthocyanin molecule A11 was most likely the first cyanin derived from the multiple modification steps of cyanidin. In addition, in the same growth condition, rosette leaves of pap1-D plants produced much higher levels and more diverse molecular profiling of cyanins than those of WT plants. The transcript levels of PAP1, PAL1, CHS, DFR, and ANS cDNAs were much higher in pap1-D rosette leaves than in WT ones. Furthermore, on the same agar-solidified medium, an enhancement of light intensity increased levels and molecular diversity of cyanins in both pap1-D and WT rosette leaves. In the same light intensity condition, the responses of anthocyanin levels and profiling to medium alternation were different between pap1-D and WT plants.

  17. Quality evaluation of green tea leaf cultured under artificial light condition using gas chromatography/mass spectrometry.

    PubMed

    Miyauchi, Shunsuke; Yonetani, Tsutomu; Yuki, Takayuki; Tomio, Ayako; Bamba, Takeshi; Fukusaki, Eiichiro

    2017-02-01

    For an experimental model to elucidate the relationship between light quality during plant culture conditions and plant quality of crops or vegetables, we cultured tea plants (Camellia sinensis) and analyzed their leaves as tea material. First, metabolic profiling of teas from a tea contest in Japan was performed with gas chromatography/mass spectrometry (GC/MS), and then a ranking predictive model was made which predicted tea rankings from their metabolite profile. Additionally, the importance of some compounds (glutamine, glutamic acid, oxalic acid, epigallocatechin, phosphoric acid, and inositol) was elucidated for measurement of the quality of tea leaf. Subsequently, tea plants were cultured in artificial conditions to control these compounds. From the result of prediction by the ranking predictive model, the tea sample supplemented with ultraviolet-A (315-399 nm) showed the highest ranking. The improvement in quality was thought to come from the high amino-acid and decreased epigallocatechin content in tea leaves. The current study shows the use and value of metabolic profiling in the field of high-quality crops and vegetables production that has been conventionally evaluated by human sensory analysis. Metabolic profiling enables us to form hypothesis to understand and develop high quality plant cultured under artificial condition.

  18. High light-induced switch from C(3)-photosynthesis to Crassulacean acid metabolism is mediated by UV-A/blue light.

    PubMed

    Grams, Thorsten E E; Thiel, Stephan

    2002-06-01

    The high light-induced switch in Clusia minor from C(3)-photosynthesis to Crassulacean acid metabolism (CAM) is fast (within a few days) and reversible. Although this C(3)/CAM transition has been studied intensively, the nature of the photoreceptor at the beginning of the CAM-induction signal chain is still unknown. Using optical filters that only transmit selected wavelengths, the CAM light induction of single leaves was tested. As controls the opposite leaf of the same leaf pair was studied in which CAM was induced by high unfiltered radiation (c. 2100 micromol m(-2) s(-1)). To evaluate the C(3)-photosynthesis/CAM transition, nocturnal CO(2) uptake, daytime stomatal closure and organic acid levels were monitored. Light at wavelengths longer than 530 nm was not effective for the induction of the C(3)/CAM switch in C. minor. In this case CAM was present in the control leaf while the opposite leaf continued performing C(3)-photosynthesis, indicating that CAM induction triggered by high light conditions is wavelength-dependent and a leaf internal process. Leaves subjected to wavelengths in the range of 345-530 nm performed nocturnal CO(2) uptake, (partial) stomatal closure during the day (CAM-phase III), and decarboxylation of citric acid within the first 2 d after the switch to high light conditions. Based on these experiments and evidence from the literature, it is suggested that a UV-A/blue light receptor mediates the light-induced C(3)-photosynthesis/CAM switch in C. minor.

  19. Photosynthetic responses of sun- and shade-grown barley leaves to high light: is the lower PSII connectivity in shade leaves associated with protection against excess of light?

    PubMed

    Zivcak, Marek; Brestic, Marian; Kalaji, Hazem M; Govindjee

    2014-03-01

    In this study, we have compared photosynthetic performance of barley leaves (Hordeum vulgare L.) grown under sun and shade light regimes during their entire growth period, under field conditions. Analyses were based on measurements of both slow and fast chlorophyll (Chl) a fluorescence kinetics, gas exchange, pigment composition; and of light incident on leaves during their growth. Both the shade and the sun barley leaves had similar Chl a/b and Chl/carotenoid ratios. The fluorescence induction analyses uncovered major functional differences between the sun and the shade leaves: lower connectivity among Photosystem II (PSII), decreased number of electron carriers, and limitations in electron transport between PSII and PSI in the shade leaves; but only low differences in the size of PSII antenna. We discuss the possible protective role of low connectivity between PSII units in shade leaves in keeping the excitation pressure at a lower, physiologically more acceptable level under high light conditions.

  20. New application of superconductors: High sensitivity cryogenic light detectors

    NASA Astrophysics Data System (ADS)

    Cardani, L.; Bellini, F.; Casali, N.; Castellano, M. G.; Colantoni, I.; Coppolecchia, A.; Cosmelli, C.; Cruciani, A.; D'Addabbo, A.; Di Domizio, S.; Martinez, M.; Tomei, C.; Vignati, M.

    2017-02-01

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs) that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2×2 cm2 substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement.

  1. HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING

    SciTech Connect

    Paul T. Fini; Shuji Nakamura

    2003-10-30

    In this second annual report we summarize the progress in the second-year period of Department of Energy contract DE-FC26-01NT41203, entitled ''High- Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has recently made significant progress in the development of light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV), resonant-cavity LEDs (RCLEDs), as well as lateral epitaxial overgrowth (LEO) techniques to obtain large-area non-polar GaN films with low average dislocation density. The Rensselaer team has benchmarked the performance of commercially available LED systems and has also conducted efforts to develop an optimized RCLED packaging scheme, including development of advanced epoxy encapsulant chemistries.

  2. Fluorescence lifetime analyses reveal how the high light-responsive protein LHCSR3 transforms PSII light-harvesting complexes into an energy-dissipative state.

    PubMed

    Kim, Eunchul; Akimoto, Seiji; Tokutsu, Ryutaro; Yokono, Makio; Minagawa, Jun

    2017-09-27

    In green algae, light-harvesting complex stress-related 3 (LHCSR3) is responsible for the pH-dependent dissipation of absorbed light energy, a function vital for survival under high-light conditions. LHCSR3 binds the photosystem II and light-harvesting complex II (PSII-LHCII) supercomplex and transforms it into an energy-dissipative form under acidic conditions, but the molecular mechanism remains unclear. Here we show that in the green alga Chlamydomonas reinhardtii, LHCSR3 modulates the excitation energy flow and dissipates the excitation energy within the light-harvesting complexes of the PSII supercomplex. Using fluorescence decay-associated spectra analysis, we found that, when the PSII supercomplex is associated with LHCSR3 under high-light conditions, excitation energy transfer from light-harvesting complexes to the chlorophyll-binding protein CP43 is selectively inhibited compared with that to CP47, preventing excess excitation energy from overloading the reaction center. By analyzing femtosecond upconversion fluorescence kinetics, we further found that pH- and LHCSR3-dependent quenching of the PSII-LHCII-LHCSR3 supercomplex is accompanied by a fluorescence emission centered at 684 nm, with a decay time constant of 18.6 ps, which is equivalent to the rise time constant of the lutein radical cation generated within a chlorophyll-lutein heterodimer. These results suggest a mechanism in which LHCSR3 transforms the PSII supercomplex into an energy-dissipative state and provide critical insight into the molecular events and characteristics in LHCSR3-dependent energy quenching. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  3. The High School Strength and Conditioning Professional: A Job Description.

    ERIC Educational Resources Information Center

    Best, Randy

    2001-01-01

    Presents a job description for the high school strength and conditioning professional, who is in a unique position to integrate athletics and academics, highlighting: minimum qualifications; school-related benefits derived from employing a strength and conditioning professional; whom the professional reports to and works with; job…

  4. Determination of light absorption, scattering and anisotropy factor of a highly scattering medium using backscattered circularly polarized light

    NASA Astrophysics Data System (ADS)

    Xu, M.; Alrubaiee, M.; Gayen, S. K.; Alfano, R. R.

    2007-02-01

    The absorption coefficient, the scattering coefficient and the anisotropy factor of a highly scattering medium are determined using the diffuse reflectance of an obliquely incident beam of circularly polarized light. This approach determines both the anisotropy factor and the cutoff size parameter for the fractal continuous scattering medium such as biological tissue and tissue phantoms from depolarization of the backscattered light.

  5. Temperature and light conditions at different latitudes affect sensory quality of broccoli florets (Brassica oleracea L. var. italica).

    PubMed

    Johansen, Tor J; Mølmann, Jørgen Ab; Bengtsson, Gunnar B; Schreiner, Monica; Velasco, Pablo; Hykkerud, Anne L; Cartea, Elena; Lea, Per; Skaret, Josefine; Seljåsen, Randi

    2017-08-01

    Broccoli (Brassica oleracea L. var. italica) is a popular vegetable grown at a wide range of latitudes. Plants were grown in 2009-2011 in pots with standardized soil, irrigation and nutrient supply under natural temperature and light conditions at four locations (42-70° N). A descriptive sensory analysis of broccoli florets was performed by a trained panel to examine any differences along the latitudinal gradient for 30 attributes within appearance, odour, taste/flavour and texture. Average results over three summer seasons in Germany, southern Norway and northern Norway showed that the northernmost location with low temperatures and long days had highest scores for bud coarseness and uniform colour, while broccoli from the German location, with high temperatures and shorter days, had highest intensity of colour hue, whiteness, bitter taste, cabbage flavour, stale flavour and watery flavour. Results from two autumn seasons at the fourth location (42° N, Spain), with low temperatures and short days, tended toward results from the two northernmost locations, with an exception for most texture attributes. Results clearly demonstrate that temperature and light conditions related to latitude and season affect the sensory quality of broccoli florets. Results may be used in marketing special quality regional or seasonal products. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. Light

    NASA Astrophysics Data System (ADS)

    Vernon, C. G.

    2016-09-01

    Preface; 1. Historical; 2. Waves and wave-motion; 3. The behaviour of ripples; 4. The behaviour of light; 5. Refraction through glass blocks and prisms; 6. The imprinting of curvatures; 7. Simple mathematical treatment; 8. More advanced mathematical treatment; 9. The velocity of light; 10. The spectrum and colour; 11. Geometrical optics; 12. The eye and optical instruments; 13. Sources of light; 14. Interference, diffraction and polarisation; 15. Suggestions for class experiments; Index.

  7. Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell.

    PubMed

    Choe, Se-Woon; Park, Kitae; Park, Chulwoo; Ryu, Jaemyung; Choi, Hojong

    2017-09-28

    Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors. We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells. Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%). We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

  8. Light Conditions Affect the Measurement of Oceanic Bacterial Production via Leucine Uptake

    PubMed Central

    Morán, Xosé Anxelu G.; Massana, Ramon; Gasol, Josep M.

    2001-01-01

    The effect of irradiance in the range of 400 to 700 nm or photosynthetically active radiation (PAR) on bacterial heterotrophic production estimated by the incorporation of 3H-leucine (referred to herein as Leu) was investigated in the northwestern Mediterranean Sea and in a coastal North Atlantic site, with Leu uptake rates ranging over 3 orders of magnitude. We performed in situ incubations under natural irradiance levels of Mediterranean samples taken from five depths around solar noon and compared them to incubations in the dark. In two of the three stations large differences were found between light and dark uptake rates for the surfacemost samples, with dark values being on average 133 and 109% higher than in situ ones. Data obtained in coastal North Atlantic waters confirmed that dark enclosure may increase Leu uptake rates more than threefold. To explain these differences, on-board experiments of Leu uptake versus irradiance were performed with Mediterranean samples from depths of 5 and 40 m. Incubations under a gradient of 12 to 1,731 μmol of photons m−2 s−1 evidenced a significant increase in incorporation rates with increasing PAR in most of the experiments, with dark-incubated samples departing from this pattern. These results were not attributed to inhibition of Leu uptake in the light but to enhanced bacterial response when transferred to dark conditions. The ratio of dark to light uptake rates increased as dissolved inorganic nitrogen concentrations decreased, suggesting that bacterial nutrient deficiency was overcome by some process occurring only in the dark bottles. PMID:11525969

  9. High-performance next-generation EUV lithography light source

    NASA Astrophysics Data System (ADS)

    Choi, Peter; Zakharov, Sergey V.; Aliaga-Rossel, Raul; Benali, Otman; Duffy, Grainne; Sarroukh, Ouassima; Wyndham, Edmund; Zakharov, Vasily S.

    2009-03-01

    EUVL solution for HVM at the 22 nm node requires a high power long-term EUV source operation with hundreds of watts at the intermediate focus output. EUV mask blank and mask defects inspections require at-wavelength tools with high brightness. Theoretical analysis with a 2-D radiation MHD code Z* has been performed to address key issues in EUV plasma sources with radiation transfer. The study shows that self-absorption defines the limiting brightness of a single EUV source, which cannot meet the requirements of the HVM tool with high efficiency and is not sufficient for critical metrology applications, given the limiting etendue of the optics. It is shown that the required irradiance can be achieved by spatial multiplexing, using multiple small sources. We present here details of the study, as well as experimental results from a novel EUV light source with an intrinsic photon collector demonstrating high brightness, the i-SoCoMo concept, where an impulse micro discharge plasma source is integrated to a photon collector based on an active plasma structure. The small physical size and low etendue properties of the i-SoCoMo unit allows a large number of such sources to be put together in one physical package and be operated in a multiplexed fashion to meet necessary power requirements.

  10. Modifying the high rate algal pond light environment and its effects on light absorption and photosynthesis.

    PubMed

    Sutherland, Donna L; Montemezzani, Valerio; Howard-Williams, Clive; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

    2015-03-01

    The combined use of high rate algal ponds (HRAPs) for wastewater treatment and commercial algal production is considered to be an economically viable option. However, microalgal photosynthesis and biomass productivity is constrained in HRAPs due to light limitation. This paper investigates how the light climate in the HRAP can be modified through changes in pond depth, hydraulic retention time (HRT) and light/dark turnover rate and how this impacts light absorption and utilisation by the microalgae. Wastewater treatment HRAPs were operated at three different pond depth and HRT during autumn. Light absorption by the microalgae was most affected by HRT, significantly decreasing with increasing HRT, due to increased internal self-shading. Photosynthetic performance (as defined by Pmax, Ek and α), significantly increased with increasing pond depth and decreasing HRT. Despite this, increasing pond depth and/or HRT, resulted in decreased pond light climate and overall integrated water column net oxygen production. However, increased light/dark turnover was able to compensate for this decrease, bringing the net oxygen production in line with shallower ponds operated at shorter HRT. On overcast days, modelled daily net photosynthesis significantly increased with increased light/dark turnover, however, on clear days such increased turnover did not enhance photosynthesis. This study has showed that light absorption and photosynthetic performance of wastewater microalgae can be modified through changes to pond depth, HRT and light/dark turnover.

  11. Rhodobacter capsulatus Catalyzes Light-Dependent Fe(II) Oxidation under Anaerobic Conditions as a Potential Detoxification Mechanism▿

    PubMed Central

    Poulain, Alexandre J.; Newman, Dianne K.

    2009-01-01

    Diverse bacteria are known to oxidize millimolar concentrations of ferrous iron [Fe(II)] under anaerobic conditions, both phototrophically and chemotrophically. Yet whether they can do this under conditions that are relevant to natural systems is understood less well. In this study, we tested how light, Fe(II) speciation, pH, and salinity affected the rate of Fe(II) oxidation by Rhodobacter capsulatus SB1003. Although R. capsulatus cannot grow photoautotrophically on Fe(II), it oxidizes Fe(II) at rates comparable to those of bacteria that do grow photoautotrophically on Fe(II) as soon as it is exposed to light, provided it has a functional photosystem. Chelation of Fe(II) by diverse organic ligands promotes Fe(II) oxidation, and as the pH increases, so does the oxidation rate, except in the presence of nitrilotriacetate; nonchelated forms of Fe(II) are also more rapidly oxidized at higher pH. Salt concentrations typical of marine environments inhibit Fe(II) oxidation. When growing photoheterotrophically on humic substances, R. capsulatus is highly sensitive to low concentrations of Fe(II); it is inhibited in the presence of concentrations as low as 5 μM. The product of Fe(II) oxidation, ferric iron, does not hamper growth under these conditions. When other parameters, such as pH or the presence of chelators, are adjusted to promote Fe(II) oxidation, the growth inhibition effect of Fe(II) is alleviated. Together, these results suggest that Fe(II) is toxic to R. capsulatus growing under strictly anaerobic conditions and that Fe(II) oxidation alleviates this toxicity. PMID:19717624

  12. Dorsal light response and changes of its responses under varying acceleration conditions.

    PubMed

    Watanabe, S; Takabayashi, A; Takagi, S; von Baumgarten, R; Wetzig, J

    1989-01-01

    In order to improve our understanding about functions of the gravity sensors, we have conducted four experiments in goldfish: 1) To define the effect of visual information influx on the static labyrinthine response, the dorsal light response (DLR) which had been proposed by von Holst as a model for postural adjustment in fish was reexamined with a newly designed, rotatory illumination device. The fish responded to illumination from the upper half of the visual field and a narrow range around 180 degrees of the lower half visual field. The maximal tilting angle of normal fish was about 40 degrees under horizontal illumination. 2) Under the changes of the gravito-inertial force level produced by a linear sled, the threshold of the gravity sensors was determined from postural adjustment responses. 3) Under hypogravic conditions during the parabolic flight of an airplane, the light-dependent behavior was investigated in intact and labyrinthectomized goldfish. 4) As one of the most likely candidates of the neural centers for the DLR, the valvula cerebelli, which receives its visual information not through the optic tectum but through the pretectal areas, is confirmed by the brain lesion experiments.

  13. High Incidence of Breast Cancer in Light-Polluted Areas with Spatial Effects in Korea.

    PubMed

    Kim, Yun Jeong; Park, Man Sik; Lee, Eunil; Choi, Jae Wook

    2016-01-01

    We have reported a high prevalence of breast cancer in light-polluted areas in Korea. However, it is necessary to analyze the spatial effects of light polluted areas on breast cancer because light pollution levels are correlated with region proximity to central urbanized areas in studied cities. In this study, we applied a spatial regression method (an intrinsic conditional autoregressive [iCAR] model) to analyze the relationship between the incidence of breast cancer and artificial light at night (ALAN) levels in 25 regions including central city, urbanized, and rural areas. By Poisson regression analysis, there was a significant correlation between ALAN, alcohol consumption rates, and the incidence of breast cancer. We also found significant spatial effects between ALAN and the incidence of breast cancer, with an increase in the deviance information criterion (DIC) from 374.3 to 348.6 and an increase in R2 from 0.574 to 0.667. Therefore, spatial analysis (an iCAR model) is more appropriate for assessing ALAN effects on breast cancer. To our knowledge, this study is the first to show spatial effects of light pollution on breast cancer, despite the limitations of an ecological study. We suggest that a decrease in ALAN could reduce breast cancer more than expected because of spatial effects.

  14. Experimental demonstration of parallel phase-shifting digital holography under weak light condition

    NASA Astrophysics Data System (ADS)

    Miao, Lin; Tahara, Tatsuki; Xia, Peng; Ito, Yasunori; Nitta, Kouichi; Awatsuji, Yasuhiro; Matoba, Osamu

    2014-03-01

    One of advantages of parallel phase-shifting digital holography (PPSDH) compared with other digital holography techniques is the fast recording of three-dimensional (3D) objects. During the fast recording of a multiplexed hologram that contains at least three amounts of phase retardation, the optical energy of the hologram becomes smaller. Therefore, it is important to assess the minimum optical energy that can reconstruct the object with moderate reconstruction error. In this paper, we investigate experimentally the optical energy to reconstruct the object under weak light condition in PPSDH. We compare the numerical and experimental results. The experiment is in good agreement with numerical results when the sensitivity of the image sensor is taken into account.

  15. Active imaging systems to see through adverse conditions: Light-scattering based models and experimental validation

    NASA Astrophysics Data System (ADS)

    Riviere, Nicolas; Ceolato, Romain; Hespel, Laurent

    2014-10-01

    Onera, the French aerospace lab, develops and models active imaging systems to understand the relevant physical phenomena affecting these systems performance. As a consequence, efforts have been done on the propagation of a pulse through the atmosphere and on target geometries and surface properties. These imaging systems must operate at night in all ambient illumination and weather conditions in order to perform strategic surveillance for various worldwide operations. We have implemented codes for 2D and 3D laser imaging systems. As we aim to image a scene in the presence of rain, snow, fog or haze, we introduce such light-scattering effects in our numerical models and compare simulated images with measurements provided by commercial laser scanners.

  16. Environmental degradation of polyacrylamides. 1. Effects of artificial environmental conditions: temperature, light, and pH.

    PubMed

    Smith, E A; Prues, S L; Oehme, F W

    1996-11-01

    A polyacrylamide thickening agent (PATA) was formulated at four concentrations in distilled-deionized water, without and with a glyphosate-surfactant herbicide (GH). Over a 6-week period, these mixtures were exposed to various controlled temperature and light conditions. Acrylamide concentration, ammonium concentration, and pH were measured at weekly intervals to assess the degradation of polyacrylamide and acrylamide. Satellite studies were conducted to examine the effect of altered pH on solutions of PATA (i.e., does pH promote polyacrylamide depolymerization?) and GH binding to amine groups (i.e., protection from degradation). The results of these studies suggest that polyacrylamide can degrade to acrylamide by thermal and photolytic effects, that changes in pH do not promote the depolymerization of polyacrylamide, and that GH does protect polyacrylamide and acrylamide from environmental degradation. Statistically there was no linear correlation between the various parameters measured.

  17. Three dimensional imaging by partially coherent light under non-paraxial condition

    PubMed Central

    Sung, Yongjin; Sheppard, Colin J. R.

    2012-01-01

    In this paper, we present the theory of 3-D imaging using partially coherent light under the non-paraxial condition. Using the linear system approach, we derive the image intensity in terms of the 3-D non-paraxial transmission cross-coefficient (TCC) and the transmission function defined in this paper. We present that the 3-D TCC can be calculated by multiple applications of the 3-D FFT instead of the 6-D integral in the original formula. Using the simplified formula, we simulate phase contrast and Nomarski-DIC (differential interference contrast) imaging of a transparent 3-D object. Within our knowledge, the 3-D model for the DIC based on the 3-D non-paraxial TCC is the most rigorous approach that has been suggested. It demonstrates clearly the optical sectioning effect of DIC. PMID:21478949

  18. High efficiency quantum dot light emitting diodes from positive aging.

    PubMed

    Acharya, Krishna P; Titov, Alexandre; Hyvonen, Jake; Wang, Chenggong; Tokarz, Jean; Holloway, Paul H

    2017-10-05

    Colloidal quantum dot-polymer hybrid light emitting diodes (QLEDs) that exhibit external quantum efficiencies >12% for all three primary colors (21% from green) have been demonstrated. These high efficiencies result in part from a positive aging effect reported here for the first time, where positive aging means the efficiency of the QLED increased with time. We have achieved 470 h operational life time (T90) at 2550 nits for red QLEDs. At longer times, negative aging phenomena lead to lower luminance and limit the lifetime of the QLEDs. It is concluded that we have reasonable control over the efficiency of QLEDs. The next challenge is to achieve lifetimes sufficiently long for all three primary colors for applications such as in television and illumination.

  19. High-order harmonics in light curves of Kepler planets

    NASA Astrophysics Data System (ADS)

    Armstrong, Caden; Rein, Hanno

    2015-10-01

    The Kepler mission was launched in 2009 and has discovered thousands of planet candidates. In a recent paper, Esteves et al. found a periodic signal in the light curves of KOI-13 and HAT-P-7, with a frequency triple the orbital frequency of a transiting planet. We found similar harmonics in many systems with a high occurrence rate. At this time, the origins of the signal are not entirely certain. We look carefully at the possibility of errors being introduced through our data processing routines but conclude that the signal is real. The harmonics on multiples of the orbital frequency are a result of non-sinusoidal periodic signals. We speculate on their origin and generally caution that these harmonics could lead to wrong estimates of planet albedos, beaming mass estimates, and ellipsoidal variations.

  20. Developmental expression of violaxanthin de-epoxidase in leaves of tobacco growing under high and low light

    SciTech Connect

    Bugos, R.C.; Chang, S.H.; Yamamoto, H.Y.

    1999-09-01

    Violaxanthin de-epoxidase (BDE) is a lumen-localized enzyme that catalyzes the de-epoxidation of violaxanthin in the thylakoid membrane upon formation of a transthylakoin pH gradient. The authors investigated the developmental expression of VDE in leaves of mature tobacco (Nicotiana tabacum) plants grown under high-light conditions (in the field) and low-light conditions (in a growth chamber). The difference in light conditions was evident by the increased pool size (violaxanthin + antheraxanthin - zeaxanthin, VAZ) throughout leaf development in field-grown plants. VDE activity based on chlorophyll or leaf area was low in the youngest leaves, with the levels increasing with increasing leaf age in both high- and low-light-grown plants. However, in high-light-grown plants, the younger leaves in early leaf expansion showed a more rapid increase in VDE activity and maintained higher levels of VDE transcript in more leaves, indicating that high light may induce greater levels of VDE. VDE transcript levels deceased substantially in leaves of mid-leaf expansion, which the levels of enzyme continued to increase, suggesting that the VDE enzyme does not turn over rapidly. The level of VDE changed in an inverse, nonlinear relationship with respect to the VAZ pool, suggesting that enzyme levels could be indirectly regulated by the VAZ pool.

  1. Retinal isomer composition in some bacteriorhodopsin mutants under light and dark adaptation conditions

    SciTech Connect

    Song, L.; Yang, D.; El-Sayed, M.A.; Lanyi, J.K.

    1995-06-15

    The isomeric composition of retinal was measured in a number of bacteriorhodopsin (bR) mutants (D85N, D212N, R82A, Y185F, and D115N) under various conditions, using a rapid retinal extraction technique followed by HPLC analysis. Besides the 13-cis and the all-trans retinal isomers observed in wild type (wt) bR under physiological conditions, the 11-cis and 9-cis retinal isomers were observed in variable but minor amounts in the bR mutants. In addition, the values of the equilibrium constant at two temperatures and the enthalpy change for the all-trans to 13-cis isomerization process in the dark-adapted state of D212N, D85N, deionized blue bR, and wt bR were determined. We find that perturbation of the retinal cavity (pocket) by residue replacement changes the relative thermal stability of the different retinal isomers, allowing for thermal-and/or photoisomerization of the retinal chromophore along C{sub 9}-C{sub 10} and C{sub 11}-C{sub 12} bonds to moderately compete with the isomerization around the C{sub 13}-C{sub 14} bond. The bR mutants expressed in Halobacterium salinarium studied in the present work showed normal 13-cis to all-trans light adaptation, in contrast with abnormal all-trans to 13-cis light adaptation observed for D212E, D212A, and D212N expressed in Escherichia coli, suggesting an influence of the purple membrane lattice and/or the lipids on the stability of the different retinal isomers within the protein. 38 refs., 2 tabs.

  2. Light and water are not simple conditions: fine tuning of animal housing in male C57BL/6 mice.

    PubMed

    Langgartner, Dominik; Foertsch, Sandra; Füchsl, Andrea M; Reber, Stefan O

    2017-01-01

    While animal housing conditions are highly controlled and standardized between different laboratories, there are still many subtle differences that unavoidably influence the host organisms and, consequently, interlaboratory reproducibility. Here, we investigated the physiological and immunological consequences between two light/dark cycle (LDC) lengths (14-h/10-h vs. 12-h/12-h LDC) and two commonly used forms of drinking water (acidified drinking water (AW) versus normal tap water (NW)) in single-housed (SH) mice. Our results indicate that SH mice bred under a 12-h/12-h LDC and NW at the supplier's facility showed increased basal morning plasma corticosterone (CORT) levels even 4 weeks after arrival at our animal facility employing a 14-h/10-h LDC and AW. This effect was even more pronounced two weeks after arrival and had abated after 8 weeks. In agreement, increased plasma adrenocorticotropic hormone (ACTH), adrenal in vitro ACTH sensitivity, as well as relative and absolute adrenal weight normalized during this 8-week exposure to the novel and unfamiliar 14-h/10-h LDC and AW. Employment of a 12-h/12-h LDC in our facility completely abrogated the CORT-elevating effects of the 14-h/10-h LDC, despite these animals drinking AW. When both the water and light conditions were matched to those at the supplier's facility, we observed a further reduction in adrenal weight, increased thymus weight, and decreased pro-inflammatory cytokine secretion of isolated and anti-CD3/28-stimulated mesenteric lymph node cells. In summary, our results indicate that prolonged alteration of both the light phase and drinking water represent severe and long-lasting stressors for laboratory rodents. These findings are of general interest for all scientists obtaining their experimental animals from conventional suppliers.

  3. Nonreflective boundary conditions for high-order methods

    NASA Technical Reports Server (NTRS)

    Atkins, H.; Casper, Jay

    1994-01-01

    A different approach to nonreflective boundary conditions for the Euler equations is presented. This work is motivated by a need for inflow and outflow boundary conditions that do not limit the useful accuracy of high-order accurate methods. The primary interest is in the propagation and convection of continuous acoustic and convective waves. This new approach employs the exact solution to finite waves to relate interior values and ambient conditions to boundary values. The method is first presented in one dimension and then generalized to multidimensions. Grid refinement studies are used to demonstrate high-order convergence for both one-dimensional and two-dimensional flows.

  4. Nonreflective boundary conditions for high-order methods

    NASA Technical Reports Server (NTRS)

    Atkins, H. L.; Casper, Jay

    1993-01-01

    A different approach to nonreflective boundary conditions for the Euler equations is presented. This work is motivated by a need for in and outflow boundary conditions that do not limit the useful accuracy of high-order accurate methods. The primary interest is in the propagation and convection of continuous acoustic and convective waves. This new approach employs the exact solution to finite waves to relate interior values and ambient conditions to boundary values. The method is first presented in one dimension and then generalized to multidimensions. Grid refinement studies are used to demonstrate high-order convergence for both one-dimensional and two-dimensional flows.

  5. High-speed Light Peak optical link for high energy applications

    NASA Astrophysics Data System (ADS)

    Chang, F. X.; Chiang, F.; Deng, B.; Hou, J.; Hou, S.; Liu, C.; Liu, T.; Teng, P. K.; Wang, C. H.; Xu, T.; Ye, J.

    2014-11-01

    Optical links provide high speed data transmission with low mass fibers favorable for applications in high energy experiments. We report investigation of a compact Light Peak optical engine designed for data transmission at 4.8 Gbps. The module is assembled with bare die VCSEL, PIN diodes and a control IC aligned within a prism receptacle for light coupling to fiber ferrule. Radiation damage in the receptacle was examined with 60Co gamma ray. Radiation induced single event effects in the optical engine were studied with protons, neutrons and X-ray tests.

  6. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    PubMed

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings.

  7. Highly reactive light-dependent monoterpenes in the Amazon

    DOE PAGES

    Jardine, A. B.; Jardine, K. J.; Fuentes, J. D.; ...

    2015-03-06

    Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. Here we report vertically resolved ambient air mixing ratios for 12 monoterpenes in a central Amazon rainforest including observations of the highly reactive cis-β-ocimene (160 ppt), trans-β-ocimene (79 ppt), and terpinolene (32 ppt) which accounted for an estimated 21% of total monoterpene composition yet 55% of the upper canopy monoterpene ozonolysis rate. All 12 monoterpenes showed a mixing ratio peak in the upper canopy, with three demonstrating subcanopy peaks in 7 of 11 profiles. Leaf level emissionsmore » of highly reactive monoterpenes accounted for up to 1.9% of photosynthesis confirming light-dependent emissions across several Amazon tree genera. These results suggest that highly reactive monoterpenes play important antioxidant roles during photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation via ozonolysis.« less

  8. Handling high data rate detectors at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Pedersen, U. K.; Rees, N.; Basham, M.; Ferner, F. J. K.

    2013-03-01

    An increasing number of area detectors, in use at Diamond Light Source, produce high rates of data. In order to capture, store and process this data High Performance Computing (HPC) systems have been implemented. This paper will present the architecture and usage for handling high rate data: detector data capture, large volume storage and parallel processing. The EPICS area Detector frame work has been adopted to abstract the detectors for common tasks including live processing, file format and storage. The chosen data format is HDF5 which provides multidimensional data storage and NeXuS compatibility. The storage system and related computing infrastructure include: a centralised Lustre based parallel file system, a dedicated network and a HPC cluster. A well defined roadmap is in place for the evolution of this to meet demand as the requirements and technology advances. For processing the science data the HPC cluster allow efficient parallel computing, on a mixture of ×86 and GPU processing units. The nature of the Lustre storage system in combination with the parallel HDF5 library allow efficient disk I/O during computation jobs. Software developments, which include utilising optimised parallel file reading for a variety of post processing techniques, are being developed in collaboration as part of the Pan-Data EU Project (www.pan-data.eu). These are particularly applicable to tomographic reconstruction and processing of non crystalline diffraction data.

  9. Super high power mid-infrared femtosecond light bullet

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, Paris; Whalen, Patrick; Kolesik, Miroslav; Moloney, Jerome V.

    2015-08-01

    Mid-infrared ultrashort high energy laser sources are opening up new opportunities in science, including keV-class high harmonic generation and monoenergetic MeV-class proton acceleration. As new higher energy sources become available, potential applications for atmospheric propagation can dramatically grow to include stand-off detection, laser communications, shock-driven remote terahertz enhancement and extended long-lived thermal waveguides to transport high power microwave and radiofrequency waves. We reveal a new paradigm for long-range, low-loss, ultrahigh power ultrashort pulse propagation at mid-infrared wavelengths in the atmosphere. Before the onset of critical self-focusing, energy in the fundamental wave continually leaks into shock-driven spectrally broadened higher harmonics. A persistent near-invariant solitonic leading edge on the multi-terawatt pulse waveform transports most of the power over hundred-metre-long distances. Such light bullets are resistant to uncontrolled multiple filamentation and are expected to spark extensive research in optics, where the use of mid-infrared lasers is currently much under-utilized.

  10. Rapid Changes in the Light/Dark Cycle Disrupt Memory of Conditioned Fear in Mice

    PubMed Central

    Loh, Dawn H.; Navarro, Juliana; Hagopian, Arkady; Wang, Louisa M.; Deboer, Tom; Colwell, Christopher S.

    2010-01-01

    Background Circadian rhythms govern many aspects of physiology and behavior including cognitive processes. Components of neural circuits involved in learning and memory, e.g., the amygdala and the hippocampus, exhibit circadian rhythms in gene expression and signaling pathways. The functional significance of these rhythms is still not understood. In the present study, we sought to determine the impact of transiently disrupting the circadian system by shifting the light/dark (LD) cycle. Such “jet lag” treatments alter daily rhythms of gene expression that underlie circadian oscillations as well as disrupt the synchrony between the multiple oscillators found within the body. Methodology/Principal Findings We subjected adult male C57Bl/6 mice to a contextual fear conditioning protocol either before or after acute phase shifts of the LD cycle. As part of this study, we examined the impact of phase advances and phase delays, and the effects of different magnitudes of phase shifts. Under all conditions tested, we found that recall of fear conditioned behavior was specifically affected by the jet lag. We found that phase shifts potentiated the stress-evoked corticosterone response without altering baseline levels of this hormone. The jet lag treatment did not result in overall sleep deprivation, but altered the temporal distribution of sleep. Finally, we found that prior experience of jet lag helps to compensate for the reduced recall due to acute phase shifts. Conclusions/Significance Acute changes to the LD cycle affect the recall of fear-conditioned behavior. This suggests that a synchronized circadian system may be broadly important for normal cognition and that the consolidation of memories may be particularly sensitive to disruptions of circadian timing. PMID:20824058

  11. 15 CFR 14.14 - High risk special award conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false High risk special award conditions. 14.14 Section 14.14 Commerce and Foreign Trade Office of the Secretary of Commerce UNIFORM...-PROFIT, AND COMMERCIAL ORGANIZATIONS Pre-Award Requirements § 14.14 High risk special award...

  12. Investigation of gender- and age-related preferences of men and women regarding lighting conditions for activation and relaxation

    NASA Astrophysics Data System (ADS)

    Schweitzer, S.; Schinagl, C.; Djuras, G.; Frühwirth, M.; Hoschopf, H.; Wagner, F.; Schulz, B.; Nemitz, W.; Grote, V.; Reidl, S.; Pritz, P.; Moser, M.; Wenzl, F. P.

    2016-09-01

    In recent years, LED lighting became an indispensable alternative to conventional lighting systems. Sophisticated solutions offer not only comfortable white light with a good color rendering. They also provide the possibility of changing illuminance and color temperature. Some systems even simulate daylight over the entire day, some including natural variations as due to clouds. Such systems are supposed to support the chronobiological needs of human and to have a positive effect on well-being, performance, sleep-quality and health. Lighting can also be used to support specific aims in a situation, like to improve productivity in activation or to support recreation in relaxation. Research regarding suitable light-settings for such situations and superordinate questions like their influence on well-being and health is still incomplete. We investigated the subjective preferences of men and women regarding light-settings for activation and relaxation. We supplied two rooms and four cubes with light sources that provide the possibility of tuning illuminance, color temperature and deviation from Plackian locus. More than 80 individuals - belonging to four groups differing in gender and age - were asked to imagine activating and recovering situations for which they should adjust suitable and pleasant lighting by tuning the above mentioned light properties. It was shown that there are clear differences in the lighting conditions preferred for these two situations. Also some combined gender- and age-specific differences became apparent.

  13. Methodology of high-resolution photography for mural condition database

    NASA Astrophysics Data System (ADS)

    Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

    2015-08-01

    Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

  14. Effects of Formulation Variables and Storage Conditions on Light Protected Vitamin B12 Mixed Parenteral Formulations

    PubMed Central

    Monajjemzadeh, Farnaz; Ebrahimi, Fatemeh; Zakeri-Milani, Parvin; Valizadeh, Hadi

    2014-01-01

    Purpose: In this research the effect of vitamin B1 and B6 on cyanocobalamin stability in commercial light protected parenteral formulations and upon adding stabilizing agents will be investigated and best formulation composition and proper storage condition will be introduced. Methods: In this research some additives such as co solvents and tonicity adjusters, surfactants, antioxidants and chelating agents as well as buffer solutions, were used to improve the stability of the parenteral mixed formulations of B12 in the presence of other B vitamins (B1 and B6). Screening tests and accelerated stability tests were performed according to ICH guidelines Q1A (R2). Results: Shelf life evaluation revealed the best formulation and the proper storage condition. The results indicated the first kinetic models for all tested formulations and the optimum pH value was determined to be 5.8. There was no evidence of B12 loss when mixed with B1 and B6 in a medical syringe at room temperature for maximum of 8 hours. Conclusion: It is necessary to formulate vitamin B12 mixed parenteral solutions using proper phosphate buffers (pH=5.8) and to indicate “Store in refrigerator” on the mixed parenteral formulations of vitamin B12 with other B vitamins, which has not been expressed on the label of tested Brand formulations at the time of this study. PMID:25436187

  15. Encoding high-order cylindrically polarized light beams.

    PubMed

    Moreno, Ignacio; Davis, Jeffrey A; Cottrell, Don M; Donoso, Ramiro

    2014-08-20

    In this work we present a setup for the experimental production of cylindrically polarized beams, as well as other variations of polarized light beams. The optical system uses a single transmissive phase-only spatial light modulator, which is used to apply different spatial phase modulation to two output collinear R and L circularly polarized components. Different cylindrically polarized light beams can be obtained by applying different phase shifts to these two circularly polarized components. The system is very efficient since modulation is directly applied to the light beam (as opposed to other common methods operating in the first order of encoded diffraction gratings). Different variations to the cylindrically polarized light beams are also reported, obtained by adding linear or quadratic relative phase shifts between the two circular polarization components of the light beam. Experimental results are provided in all cases.

  16. Germination of dimorphic seeds of Suaeda aralocaspica in response to light and salinity conditions during and after cold stratification.

    PubMed

    Wang, Hong-Ling; Tian, Chang-Yan; Wang, Lei

    2017-01-01

    Cold stratification is a requirement for seed dormancy breaking in many species, and thus it is one of the important factors for the regulation of timing of germination. However, few studies have examined the influence of various environmental conditions during cold stratification on subsequent germination, and no study has compared such effects on the performance of dormant versus non-dormant seeds. Seeds of halophytes in the cold desert might experience different light and salinity conditions during and after cold stratification. As such, dimorphic seeds (non-dormant brown seeds and black seeds with non-deep physiological dormancy) of Suaeda aralocaspica were cold stratified under different light (12 h light-12 h darkness photoperiod or continuous darkness) or salinity (0, 200 or 1,000 mmol L(-1) NaCl) conditions for 20 or 40 days. Then stratified seeds were incubated under different light or salinity conditions at daily (12/12 h) temperature regime of 10:25 °C for 20 days. For brown seeds, cold stratification was also part of the germination period. In contrast, almost no black seeds germinated during cold stratification. The longer the cold stratification, the better the subsequent germination of black seeds, regardless of light or salinity conditions. Light did not influence germination of brown seeds. Germination of cold-stratified black seeds was inhibited by darkness, especially when they were stratified in darkness. With an increase in salinity at the stage of cold stratification or germination, germination percentages of both seed morphs decreased. Combinational pre-treatments of cold stratification and salinity did not increase salt tolerance of dimorphic seeds in germination phase. Thus, light and salinity conditions during cold stratification partly interact with these conditions during germination stage and differentially affect germination of dimorphic seeds of S. aralocaspica.

  17. Electric signalling in fruit trees in response to water applications and light-darkness conditions.

    PubMed

    Gurovich, Luis A; Hermosilla, Paulo

    2009-02-15

    A fundamental property of all living organisms is the generation and conduction of electrochemical impulses throughout their different tissues and organs, resulting from abiotic and biotic changes in environmental conditions. In plants and animals, signal transmission can occur over long and short distances, and it can correspond to intra- and inter-cellular communication mechanisms that determine the physiological behaviour of the organism. Rapid plant and animal responses to environmental changes are associated with electrical excitability and signalling. The same molecules and pathways are used to drive physiological responses, which are characterized by movement (physical displacement) in animals and by continuous growth in plants. In the field of environmental plant electrophysiology, automatic and continuous measurements of electrical potential differences (DeltaEP) between plant tissues can be effectively used to study information transport mechanisms and physiological responses that result from external stimuli on plants. A critical mass of data on electrical behaviour in higher plants has accumulated in the last 5 years, establishing plant neurobiology as the most recent discipline of plant science. In this work, electrical potential differences were monitored continuously using Ag/AgCl microelectrodes, which were inserted 15mm deep into sapwood at various positions in the trunks of several fruit-bearing trees. Electrodes were referenced to an unpolarisable Ag/AgCl microelectrode, which was installed 5cm deep in the soil. Systematic patterns of DeltaEP during day-night cycles and at different conditions of soil water availability are discussed as alternative tools to assess early plant stress conditions. This research relates to the adaptive response of trees to soil water availability and light-darkness cycles.

  18. Socially adjusted synchrony in the activity profiles of common marmosets in light-dark conditions.

    PubMed

    Melo, Paula; Gonçalves, Bruno; Menezes, Alexandre; Azevedo, Carolina

    2013-07-01

    Synchronized state of activity and rest might be attained by mechanisms of entrainment and masking. Most zeitgebers not only act to entrain but also to mask circadian rhythms. Although the light-dark (LD) cycle is the main zeitgeber of circadian rhythms in marmosets, social cues can act as weaker zeitgebers. Evidence on the effects of social entrainment in marmosets has been collected in isolated animals or in pairs where activity is not individually recorded. To characterize the synchronization between the daily activity profiles of individuals in groups under LD conditions, the motor activity of animals from five groups was continuously monitored using actiwatches for 15 days during the 5th, 8th, and 11th months of life of juveniles. Families consisting of twins (4 ♂♀/1 ♂♂) and their parents were maintained under controlled lighting (LD 12:12 h), temperature, and humidity conditions. Synchronization was evaluated through the synchrony between the circadian activity profiles obtained from the Pearson correlation index between possible pairs of activity profiles in the light and dark phases. We also calculated the phase-angle differences between the activity onset of one animal in relation to the activity onset of each animal in the group (ψ(on)). A similar procedure was performed for activity offset (ψ(off)). By visual analysis, the correlation between the activity profiles of individuals within each family was stronger than that of individuals from different families. A mixed-model analysis showed that within the group, the correlation was stronger between twins than between twins and their parents in all families, except for the family in which both juveniles were males. Because a twin is an important social partner for juveniles, a sibling is likely to have a stronger influence on its twin's activity rhythm than other family members. Considering only the light phase, the second strongest correlation was observed between the activity profiles of the

  19. Influence of light colours on growth and stress response of rainbow trout (Oncorhynchus mykiss) under laboratory conditions.

    PubMed

    Heydarnejad, M Saeed; Parto, M; Pilevarian, A A

    2013-02-01

    The influence of light colours on growth and stress response in rainbow trout Oncorhyncus mykiss (15.16 ± 0.29 cm; 32.27 ± 1.18 g) was studied. Fish were reared in 16 glass aquaria (140 × 30 × 80 cm) each with 12 fish under one of four different lighting spectra: yellow (546 nm), red (605 nm), blue (470 nm) and white (full spectrum, control). Experiments lasted 125 days. The stress response was evaluated by measuring cortisol levels. Body weight and total length of the fish reared under yellow light were greater compared with the other colour regimes while feed conversion ratio significantly lowers. Condition factor and specific growth rate, however, were not differentiated among experimental light treatments. Stressed fish showed lower cortisol levels under yellow light compared with other light exposures. The study indicates that under laboratory conditions, rainbow trout grow best under yellow light and that yellow light lowers the stress-induced cortisol response in this fish species. © 2011 Blackwell Verlag GmbH.

  20. Plants Actively Avoid State Transitions upon Changes in Light Intensity: Role of Light-Harvesting Complex II Protein Dephosphorylation in High Light.

    PubMed

    Mekala, Nageswara Rao; Suorsa, Marjaana; Rantala, Marjaana; Aro, Eva-Mari; Tikkanen, Mikko

    2015-06-01

    Photosystem II (PSII) core and light-harvesting complex II (LHCII) proteins in plant chloroplasts undergo reversible phosphorylation upon changes in light intensity (being under control of redox-regulated STN7 and STN8 kinases and TAP38/PPH1 and PSII core phosphatases). Shift of plants from growth light to high light results in an increase of PSII core phosphorylation, whereas LHCII phosphorylation concomitantly decreases. Exactly the opposite takes place when plants are shifted to lower light intensity. Despite distinct changes occurring in thylakoid protein phosphorylation upon light intensity changes, the excitation balance between PSII and photosystem I remains unchanged. This differs drastically from the canonical-state transition model induced by artificial states 1 and 2 lights that concomitantly either dephosphorylate or phosphorylate, respectively, both the PSII core and LHCII phosphoproteins. Analysis of the kinase and phosphatase mutants revealed that TAP38/PPH1 phosphatase is crucial in preventing state transition upon increase in light intensity. Indeed, tap38/pph1 mutant revealed strong concomitant phosphorylation of both the PSII core and LHCII proteins upon transfer to high light, thus resembling the wild type under state 2 light. Coordinated function of thylakoid protein kinases and phosphatases is shown to secure balanced excitation energy for both photosystems by preventing state transitions upon changes in light intensity. Moreover, proton gradient regulation5 (PGR5) is required for proper regulation of thylakoid protein kinases and phosphatases, and the pgr5 mutant mimics phenotypes of tap38/pph1. This shows that there is a close cooperation between the redox- and proton gradient-dependent regulatory mechanisms for proper function of the photosynthetic machinery. © 2015 American Society of Plant Biologists. All Rights Reserved.

  1. Plants Actively Avoid State Transitions upon Changes in Light Intensity: Role of Light-Harvesting Complex II Protein Dephosphorylation in High Light1[OPEN

    PubMed Central

    Suorsa, Marjaana; Rantala, Marjaana; Aro, Eva-Mari

    2015-01-01

    Photosystem II (PSII) core and light-harvesting complex II (LHCII) proteins in plant chloroplasts undergo reversible phosphorylation upon changes in light intensity (being under control of redox-regulated STN7 and STN8 kinases and TAP38/PPH1 and PSII core phosphatases). Shift of plants from growth light to high light results in an increase of PSII core phosphorylation, whereas LHCII phosphorylation concomitantly decreases. Exactly the opposite takes place when plants are shifted to lower light intensity. Despite distinct changes occurring in thylakoid protein phosphorylation upon light intensity changes, the excitation balance between PSII and photosystem I remains unchanged. This differs drastically from the canonical-state transition model induced by artificial states 1 and 2 lights that concomitantly either dephosphorylate or phosphorylate, respectively, both the PSII core and LHCII phosphoproteins. Analysis of the kinase and phosphatase mutants revealed that TAP38/PPH1 phosphatase is crucial in preventing state transition upon increase in light intensity. Indeed, tap38/pph1 mutant revealed strong concomitant phosphorylation of both the PSII core and LHCII proteins upon transfer to high light, thus resembling the wild type under state 2 light. Coordinated function of thylakoid protein kinases and phosphatases is shown to secure balanced excitation energy for both photosystems by preventing state transitions upon changes in light intensity. Moreover, PROTON GRADIENT REGULATION5 (PGR5) is required for proper regulation of thylakoid protein kinases and phosphatases, and the pgr5 mutant mimics phenotypes of tap38/pph1. This shows that there is a close cooperation between the redox- and proton gradient-dependent regulatory mechanisms for proper function of the photosynthetic machinery. PMID:25902812

  2. The study of initial conditions in collisions of light, intermediate and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Loctionov, A. A.; Arginova, A. Kh.; Gaitinov, A. Sh.; Kvochkina, T. N.

    2017-06-01

    The system size dependence for multiparticle processes has been recognized in both cosmic ray ("Stratosphere" collaboration) and at accelerator ("EMU" collaboration) experiments. The strong enhancement in multiplicity fluctuations for the most central light-light - (C, O, Ne) + (C/N/O) - collisions has been revealed at JINR-AGS-SPS energies. The sharp difference of light nuclear interactions are interpreted as the sign of intrinsic alpha-clustering in light nuclei.

  3. High light extraction efficiency in bulk-GaN based volumetric violet light-emitting diodes

    SciTech Connect

    David, Aurelien Hurni, Christophe A.; Aldaz, Rafael I.; Cich, Michael J.; Ellis, Bryan; Huang, Kevin; Steranka, Frank M.; Krames, Michael R.

    2014-12-08

    We report on the light extraction efficiency of III-Nitride violet light-emitting diodes with a volumetric flip-chip architecture. We introduce an accurate optical model to account for light extraction. We fabricate a series of devices with varying optical configurations and fit their measured performance with our model. We show the importance of second-order optical effects like photon recycling and residual surface roughness to account for data. We conclude that our devices reach an extraction efficiency of 89%.

  4. Dual design resistor for high voltage conditioning and transmission lines

    DOEpatents

    Siggins, Timothy Lynn [Newport News, VA; Murray, Charles W [Hayes, VA; Walker, Richard L [Norfolk, VA

    2007-01-23

    A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

  5. Intensive Plasmonic Flash Light Sintering of Copper Nanoinks Using a Band-Pass Light Filter for Highly Electrically Conductive Electrodes in Printed Electronics.

    PubMed

    Hwang, Yeon-Taek; Chung, Wan-Ho; Jang, Yong-Rae; Kim, Hak-Sung

    2016-04-06

    In this work, an intensive plasmonic flash light sintering technique was developed by using a band-pass light filter matching the plasmonic wavelength of the copper nanoparticles. The sintering characteristics, such as resistivity and microstructure, of the copper nanoink films were studied as a function of the range of the wavelength employed in the flash white light sintering. The flash white light irradiation conditions (e.g., wavelength range, irradiation energy, pulse number, on-time, and off-time) were optimized to obtain a high conductivity of the copper nanoink films without causing damage to the polyimide substrate. The wavelength range corresponding to the plasmonic wavelength of the copper nanoparticles could efficiently sinter the copper nanoink and enhance its conductivity. Ultimately, the sintered copper nanoink films under optimal light sintering conditions showed the lowest resistivity (6.97 μΩ·cm), which was only 4.1 times higher than that of bulk copper films (1.68 μΩ·cm).

  6. MISR empirical stray light corrections in high-contrast scenes

    NASA Astrophysics Data System (ADS)

    Limbacher, J. A.; Kahn, R. A.

    2015-07-01

    We diagnose the potential causes for the Multi-angle Imaging SpectroRadiometer's (MISR) persistent high aerosol optical depth (AOD) bias at low AOD with the aid of coincident MODerate-resolution Imaging Spectroradiometer (MODIS) imagery from NASA's Terra satellite. Stray light in the MISR instrument is responsible for a large portion of the high AOD bias in high-contrast scenes, such as broken-cloud scenes that are quite common over ocean. Discrepancies among MODIS and MISR nadir-viewing blue, green, red, and near-infrared images are used to optimize seven parameters individually for each wavelength, along with a background reflectance modulation term that is modeled separately, to represent the observed features. Independent surface-based AOD measurements from the AErosol RObotic NETwork (AERONET) and the Marine Aerosol Network (MAN) are compared with MISR research aerosol retrieval algorithm (RA) AOD retrievals for 1118 coincidences to validate the corrections when applied to the nadir and off-nadir cameras. With these corrections, plus the baseline RA corrections and enhanced cloud screening applied, the median AOD bias for all data in the mid-visible (green, 558 nm) band decreases from 0.006 (0.020 for the MISR standard algorithm (SA)) to 0.000, and the RMSE decreases by 5 % (27 % compared to the SA). For AOD558 nm < 0.10, which includes about half the validation data, 68th percentile absolute AOD558 nm errors for the RA have dropped from 0.022 (0.034 for the SA) to < 0.02 (~ 0.018).

  7. Optical design of an adaptive front-lighting system with high energy efficiency

    NASA Astrophysics Data System (ADS)

    Zhu, Xiangbing; Wang, Cheng; Wu, Han; Jiang, Long

    2014-07-01

    To meet the demands of safe and comfortable driving, we present a new design of a highly energy-efficient Adaptive Front-lighting System (AFS) that can automatically adjust the shape, range, and light distribution of the illumination. The AFS system consists of a lamp, a reflector, light pipes, a Digital Micromirror Device (DMD), a condenser, and a lens. Our simulations show that this system can achieve different beams, such as basic passing beams, town beams, motorway beams, and corner lighting. By using the second light pipe to collect light, the illumination efficiency is increased by 10 points, accordingly reducing the generated heat of the lighting system.

  8. Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol.

    PubMed

    Martinsson, J; Eriksson, A C; Nielsen, I Elbæk; Malmborg, V Berg; Ahlberg, E; Andersen, C; Lindgren, R; Nyström, R; Nordin, E Z; Brune, W H; Svenningsson, B; Swietlicki, E; Boman, C; Pagels, J H

    2015-12-15

    The aim was to identify relationships between combustion conditions, particle characteristics, and optical properties of fresh and photochemically processed emissions from biomass combustion. The combustion conditions included nominal and high burn rate operation and individual combustion phases from a conventional wood stove. Low temperature pyrolysis upon fuel addition resulted in "tar-ball" type particles dominated by organic aerosol with an absorption Ångström exponent (AAE) of 2.5-2.7 and estimated Brown Carbon contributions of 50-70% to absorption at the climate relevant aethalometer-wavelength (520 nm). High temperature combustion during the intermediate (flaming) phase was dominated by soot agglomerates with AAE 1.0-1.2 and 85-100% of absorption at 520 nm attributed to Black Carbon. Intense photochemical processing of high burn rate flaming combustion emissions in an oxidation flow reactor led to strong formation of Secondary Organic Aerosol, with no or weak absorption. PM1 mass emission factors (mg/kg) of fresh emissions were about an order of magnitude higher for low temperature pyrolysis compared to high temperature combustion. However, emission factors describing the absorption cross section emitted per kg of fuel consumed (m(2)/kg) were of similar magnitude at 520 nm for the diverse combustion conditions investigated in this study. These results provide a link between biomass combustion conditions, emitted particle types, and their optical properties in fresh and processed plumes which can be of value for source apportionment and balanced mitigation of biomass combustion emissions from a climate and health perspective.

  9. Reading performance of monofocal pseudophakic patients with and without glasses under normal and dim light conditions.

    PubMed

    Radner, Wolfgang; Radner, Stephan; Raunig, Valerian; Diendorfer, Gabriela

    2014-03-01

    To evaluate reading performance of patients with monofocal intraocular lenses (IOLs) (Acrysof SN60WF) with or without reading glasses under bright and dim light conditions. Austrian Academy of Ophthalmology, Vienna, Austria. Evaluation of a diagnostic test or technology. In pseudophakic patients, the spherical refractive error was limited to between +0.50 diopter (D) and -0.75 D with astigmatism of 0.75 D (mean spherical equivalent: right eye, -0.08 ± 0.43 [SD]; left eye, -0.15 ± 0.35). Near addition was +2.75 D. Reading performance was assessed binocularly with or without reading glasses at an illumination of 100 candelas (cd)/m(2) and 4 cd/m(2) using the Radner Reading Charts. In the 25 patients evaluated, binocularly, the mean corrected distance visual acuity was -0.07 ± 0.06 logMAR and the mean uncorrected distance visual acuity was 0.01 ± 0.11 logMAR. The mean reading acuity with reading glasses was 0.02 ± 0.10 logRAD at 100 cd/m(2) and 0.12 ± 0.14 logRAD at 4 cd/m(2). Without reading glasses, it was 0.44 ± 0.13 logRAD and 0.56 ± 0.16 logRAD, respectively (P < .05). Without reading glasses and at 100 cd/m(2), 40% of patients read 0.4 logRAD at more than 80 words per minute (wpm), 68% exceeded this limit at 0.5 logRAD, and 92% exceeded it at 0.6 logRAD. The mean reading speed at 0.5 logRAD was 134.76 ± 48.22 wpm; with reading glasses it was 167.65 ± 32.77 wpm (P < .05). A considerable percentage of patients with monofocal IOLs read newspaper print size without glasses under good light conditions. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions.

    PubMed

    Da Silva, Arnaud; Kempenaers, Bart

    2017-08-10

    Animals breeding at northern latitudes experience drastic changes in daily light conditions during the breeding season with decreasing periods of darkness, whereas those living at lower latitudes are exposed to naturally dark nights throughout the year. Nowadays, many animals are also exposed to artificial night lighting (often referred to as light pollution). Animals strongly rely on variation in light levels to time their daily and seasonal behaviour. Previous work on passerine birds showed that artificial night lighting leads to earlier onset of dawn song. However, these studies were carried out at intermediate latitudes with more limited seasonal changes in daylength, and we still lack an understanding of the impact of artificial night lighting in relation to variation in natural light conditions. We investigated the influence of natural and artificial light conditions on the timing of dawn singing in five common songbird species in each of three regions in Europe that differed in natural variation in daylength (northern Finland, 65°N; southern Germany, 48°N; southern Spain, 37°N). In each region, we selected five peri-urban forest sites with and five without street lighting, and we recorded dawn singing at the beginning of the local breeding season. Our results show that the earliest natural singers, that is, European robins (Erithacus rubecula) and common blackbirds (Turdus merula), started dawn singing earlier along with the natural increase in night brightness in Finland, with no additional effects of artificial night lighting. In contrast, the later singers, such as, great tits (Parus major), blue tits (Cyanistes caeruleus) and chaffinches (Fringilla coelebs), showed similar onsets of dawn song relative to sunrise across the season and similar effects of artificial night lighting at all latitudes. Artificial night lighting affected great tits, blue tits and chaffinches even in northern Finland where nights became very bright. Proximate factors such as

  11. An assessment of high-power light-emitting diodes for high frame rate schlieren imaging

    NASA Astrophysics Data System (ADS)

    Willert, Christian E.; Mitchell, Daniel M.; Soria, Julio

    2012-08-01

    The feasibility of using high-power light-emitting diodes (LED) as a light source for high frame rate schlieren imaging is investigated. Continuous sequences of high-intensity light pulses are achieved by overdriving the LED with current pulses up to a factor of ten beyond its specifications. In comparison to commonly used pulsed light sources such as gas discharge lamps and pulsed lasers, the pulsed LED has several attractive advantages: the pulse-to-pulse intensity variation is on the same order of magnitude as the detector (camera) noise permitting quantitative intensity measurements. The LED's narrow emission bandwidth reduces chromatic abberations, yet it is spectrally wide enough to prevent the appearance of speckle and diffraction effects in the images. Most importantly, the essentially lag-free light emission within tens of nanoseconds of the applied current pulse allows the LED to be operated at varying frequencies (i.e., asynchronously), which generally is not possible with neither lasers nor discharge lamps. The pulsed LED source, driven by a simple driver circuit, is demonstrated on two schlieren imaging setups. The first configuration visualizes the temporal evolution of shock structures and sound waves of an under-expanded jet that is impinging on a rigid surface at frame rates of 500 kHz to 1 MHz. In a second application, long sequences of several thousand high-resolution images are acquired on a free jet at a frame rate of 1 kHz. The low-intensity fluctuation and large sample number allow a reliable computation of two-point correlation data from the image sequences.

  12. Role of multiphoton bunching in high-order ghost imaging with thermal light sources

    SciTech Connect

    Liu Qian; Chen Xihao; Luo Kaihong; Wu Lingan; Wu Wei

    2009-05-15

    The intrinsic higher-order correlation of intensities which gives a measure of 'pure' correlations among photons (corresponding to multiphoton bunching) is investigated with regard to ghost imaging with thermal light. The synchronous detection of the same light field by all reference detectors, which is a necessary condition for achieving an Nth-order ghost image based on N-photon bunching, is discussed. Furthermore, it is found that the enhanced high visibility of Nth-order ghost imaging is a consequence of the contribution of N-photon bunching, which is not a small value but is equal to the sum of all contributions from (N-1)-photon bunching. These results differ from those obtained by certain other groups.

  13. Structural changes of the thylakoid membrane network induced by high light stress in plant chloroplasts.

    PubMed

    Kirchhoff, Helmut

    2014-04-19

    Land plants live in a challenging environment dominated by unpredictable changes. A particular problem is fluctuation in sunlight intensity that can cause irreversible damage of components of the photosynthetic apparatus in thylakoid membranes under high light conditions. Although a battery of photoprotective mechanisms minimize damage, photoinhibition of the photosystem II (PSII) complex occurs. Plants have evolved a multi-step PSII repair cycle that allows efficient recovery from photooxidative PSII damage. An important feature of the repair cycle is its subcompartmentalization to stacked grana thylakoids and unstacked thylakoid regions. Thus, understanding the crosstalk between stacked and unstacked thylakoid membranes is essential to understand the PSII repair cycle. This review summarizes recent progress in our understanding of high-light-induced structural changes of the thylakoid membrane system and correlates these changes to the efficiency of the PSII repair cycle. The role of reversible protein phosphorylation for structural alterations is discussed. It turns out that dynamic changes in thylakoid membrane architecture triggered by high light exposure are central for efficient repair of PSII.

  14. Evolution of quality characteristics of minimally processed asparagus during storage in different lighting conditions.

    PubMed

    Sanz, S; Olarte, C; Ayala, F; Echávarri, J F

    2009-08-01

    The effect of different types of lighting (white, green, red, and blue light) on minimally processed asparagus during storage at 4 degrees C was studied. The gas concentrations in the packages, pH, mesophilic counts, and weight loss were also determined. Lighting caused an increase in physiological activity. Asparagus stored under lighting achieved atmospheres with higher CO(2) and lower O(2) content than samples kept in the dark. This activity increase explains the greater deterioration experienced by samples stored under lighting, which clearly affected texture and especially color, accelerating the appearance of greenish hues in the tips and reddish-brown hues in the spears. Exposure to light had a negative effect on the quality parameters of the asparagus and it caused a significant reduction in shelf life. Hence, the 11 d shelf life of samples kept in the dark was reduced to only 3 d in samples kept under red and green light, and to 7 d in those kept under white and blue light. However, quality indicators such as the color of the tips and texture showed significantly better behavior under blue light than with white light, which allows us to state that it is better to use this type of light or blue-tinted packaging film for the display of minimally processed asparagus to consumers.

  15. 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

  16. Design and optimization of a back-flow limiter for the high performance light water reactor

    SciTech Connect

    Fischer, Kai; Laurien, Eckart; Claas, Andreas G.; Schulenberg, Thomas

    2007-07-01

    Design and Analysis of a back-flow limiter are presented, which is implemented as a safety device in the four inlet lines of the Reactor Pressure Vessel (RPV) of the High Performance Light Water Reactor (HPLWR). As a passive component, the back-flow limiter has no moving parts and belongs to the group of fluid diodes. It has low flow resistance for regular operation condition and a high flow resistance when the flow direction is reversed which is the case if a break of the feedwater line occurs. The increased flow resistance is due to a substantially increased swirl for reverse flow condition. The design is optimized employing 1D flow analyses in combination with 3D CFD analyses with respect to geometrical modifications, like the nozzle shape and swirler angles. (authors)

  17. Prospects for high-gain, high yield NIF targets driven by 2ω (green) light

    NASA Astrophysics Data System (ADS)

    Suter, L. J.; Glenzer, S.; Haan, S.; Hammel, B.; Manes, K.; Meezan, N.; Moody, J.; Spaeth, M.; Oades, K.; Stevenson, M.

    2016-10-01

    For several years we have been exploring the possibility of using green (2w) light for indirect drive ignition on NIF. The rationale for this work is the possibility of extracting significantly more energy from NIF in green light, as compared to blue (3w) light, and driving far more energetic capsules than we originally envisioned when we started planning NIF in the early 1990's. This paper attempts to provide a comprehensive picture of the progress we have made exploring 2w for NIF ignition. First we describe the potential operating regim